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Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]6 <title>Source Level Debugging with LLVM</title>
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10
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]11<h1>Source Level Debugging with LLVM</h1>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]12
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]13<table class="layout" style="width:100%">
14 <tr class="layout">
15 <td class="left">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]16<ul>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]17 <li><a href="#introduction">Introduction</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]18 <ol>
19 <li><a href="#phil">Philosophy behind LLVM debugging information</a></li>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]20 <li><a href="#consumers">Debug information consumers</a></li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]21 <li><a href="#debugopt">Debugging optimized code</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]22 </ol></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]23 <li><a href="#format">Debugging information format</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]24 <ol>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]25 <li><a href="#debug_info_descriptors">Debug information descriptors</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]26 <ul>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]27 <li><a href="#format_compile_units">Compile unit descriptors</a></li>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]28 <li><a href="#format_files">File descriptors</a></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]29 <li><a href="#format_global_variables">Global variable descriptors</a></li>
30 <li><a href="#format_subprograms">Subprogram descriptors</a></li>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]31 <li><a href="#format_blocks">Block descriptors</a></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]32 <li><a href="#format_basic_type">Basic type descriptors</a></li>
33 <li><a href="#format_derived_type">Derived type descriptors</a></li>
34 <li><a href="#format_composite_type">Composite type descriptors</a></li>
35 <li><a href="#format_subrange">Subrange descriptors</a></li>
36 <li><a href="#format_enumeration">Enumerator descriptors</a></li>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]37 <li><a href="#format_variables">Local variables</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]38 </ul></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]39 <li><a href="#format_common_intrinsics">Debugger intrinsic functions</a>
40 <ul>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]41 <li><a href="#format_common_declare">llvm.dbg.declare</a></li>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]42 <li><a href="#format_common_value">llvm.dbg.value</a></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]43 </ul></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]44 </ol></li>
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]45 <li><a href="#format_common_lifetime">Object lifetimes and scoping</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]46 <li><a href="#ccxx_frontend">C/C++ front-end specific debug information</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]47 <ol>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]48 <li><a href="#ccxx_compile_units">C/C++ source file information</a></li>
49 <li><a href="#ccxx_global_variable">C/C++ global variable information</a></li>
50 <li><a href="#ccxx_subprogram">C/C++ function information</a></li>
51 <li><a href="#ccxx_basic_types">C/C++ basic types</a></li>
52 <li><a href="#ccxx_derived_types">C/C++ derived types</a></li>
53 <li><a href="#ccxx_composite_types">C/C++ struct/union types</a></li>
54 <li><a href="#ccxx_enumeration_types">C/C++ enumeration types</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]55 </ol></li>
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]56 <li><a href="#llvmdwarfextension">LLVM Dwarf Extensions</a>
57 <ol>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]58 <li><a href="#objcproperty">Debugging Information Extension
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]59 for Objective C Properties</a></li>
60 <ul>
61 <li><a href="#objcpropertyintroduction">Introduction</a></li>
62 <li><a href="#objcpropertyproposal">Proposal</a></li>
63 <li><a href="#objcpropertynewattributes">New DWARF Attributes</a></li>
64 <li><a href="#objcpropertynewconstants">New DWARF Constants</a></li>
65 </ul>
Eric Christopher25e63292012-03-06 02:25:38 +0000[diff] [blame^]66 <li><a href="#acceltable">Name Accelerator Tables</a></li>
67 <ul>
68 <li><a href="#acceltableintroduction">Introduction</a></li>
69 <li><a href="#acceltablehashes">Hash Tables</a></li>
70 <li><a href="#acceltabledetails">Details</a></li>
71 <li><a href="#acceltablecontents">Contents</a></li>
72 <li><a href="#acceltableextensions">Language Extensions and File Format Changes</a></li>
73 </ul>
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]74 </ol>
75 </li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]76</ul>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]77</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]78<td class="right">
Misha Brukmane849a1a2004-05-12 21:26:16 +0000[diff] [blame]79<img src="img/venusflytrap.jpg" alt="A leafy and green bug eater" width="247"
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]80height="369">
81</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]82</tr></table>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]83
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]84<div class="doc_author">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]85 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
Jim Laskeyc760a922007-03-14 19:32:21 +0000[diff] [blame]86 and <a href="mailto:jlaskey@mac.com">Jim Laskey</a></p>
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]87</div>
88
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]89
90<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]91<h2><a name="introduction">Introduction</a></h2>
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]92<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]93
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]94<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]95
96<p>This document is the central repository for all information pertaining to
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]97 debug information in LLVM. It describes the <a href="#format">actual format
98 that the LLVM debug information</a> takes, which is useful for those
99 interested in creating front-ends or dealing directly with the information.
Chris Lattner8ad2f982009-07-18 21:47:15 +0000[diff] [blame]100 Further, this document provides specific examples of what debug information
Chris Lattner89940752011-01-18 06:12:10 +0000[diff] [blame]101 for C/C++ looks like.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]102
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]103<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]104<h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]105 <a name="phil">Philosophy behind LLVM debugging information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]106</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]107
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]108<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]109
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]110<p>The idea of the LLVM debugging information is to capture how the important
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]111 pieces of the source-language's Abstract Syntax Tree map onto LLVM code.
112 Several design aspects have shaped the solution that appears here. The
113 important ones are:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]114
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]115<ul>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]116 <li>Debugging information should have very little impact on the rest of the
117 compiler. No transformations, analyses, or code generators should need to
118 be modified because of debugging information.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]119
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]120 <li>LLVM optimizations should interact in <a href="#debugopt">well-defined and
121 easily described ways</a> with the debugging information.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]122
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]123 <li>Because LLVM is designed to support arbitrary programming languages,
124 LLVM-to-LLVM tools should not need to know anything about the semantics of
125 the source-level-language.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]126
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]127 <li>Source-level languages are often <b>widely</b> different from one another.
128 LLVM should not put any restrictions of the flavor of the source-language,
129 and the debugging information should work with any language.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]130
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]131 <li>With code generator support, it should be possible to use an LLVM compiler
132 to compile a program to native machine code and standard debugging
133 formats. This allows compatibility with traditional machine-code level
134 debuggers, like GDB or DBX.</li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]135</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]136
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]137<p>The approach used by the LLVM implementation is to use a small set
138 of <a href="#format_common_intrinsics">intrinsic functions</a> to define a
139 mapping between LLVM program objects and the source-level objects. The
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]140 description of the source-level program is maintained in LLVM metadata
141 in an <a href="#ccxx_frontend">implementation-defined format</a>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]142 (the C/C++ front-end currently uses working draft 7 of
143 the <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3
144 standard</a>).</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]145
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]146<p>When a program is being debugged, a debugger interacts with the user and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]147 turns the stored debug information into source-language specific information.
148 As such, a debugger must be aware of the source-language, and is thus tied to
149 a specific language or family of languages.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]150
151</div>
152
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]153<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]154<h3>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]155 <a name="consumers">Debug information consumers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]156</h3>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]157
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]158<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]159
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]160<p>The role of debug information is to provide meta information normally
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]161 stripped away during the compilation process. This meta information provides
162 an LLVM user a relationship between generated code and the original program
163 source code.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]164
Chris Lattnerc3107782010-04-05 04:11:11 +0000[diff] [blame]165<p>Currently, debug information is consumed by DwarfDebug to produce dwarf
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]166 information used by the gdb debugger. Other targets could use the same
167 information to produce stabs or other debug forms.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]168
169<p>It would also be reasonable to use debug information to feed profiling tools
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]170 for analysis of generated code, or, tools for reconstructing the original
171 source from generated code.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]172
173<p>TODO - expound a bit more.</p>
174
175</div>
176
177<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]178<h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]179 <a name="debugopt">Debugging optimized code</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]180</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]181
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]182<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]183
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]184<p>An extremely high priority of LLVM debugging information is to make it
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]185 interact well with optimizations and analysis. In particular, the LLVM debug
186 information provides the following guarantees:</p>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]187
188<ul>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]189 <li>LLVM debug information <b>always provides information to accurately read
190 the source-level state of the program</b>, regardless of which LLVM
191 optimizations have been run, and without any modification to the
192 optimizations themselves. However, some optimizations may impact the
193 ability to modify the current state of the program with a debugger, such
194 as setting program variables, or calling functions that have been
195 deleted.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]196
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]197 <li>As desired, LLVM optimizations can be upgraded to be aware of the LLVM
198 debugging information, allowing them to update the debugging information
199 as they perform aggressive optimizations. This means that, with effort,
200 the LLVM optimizers could optimize debug code just as well as non-debug
201 code.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]202
Devang Patele0bdc592011-05-31 17:45:27 +0000[diff] [blame]203 <li>LLVM debug information does not prevent optimizations from
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]204 happening (for example inlining, basic block reordering/merging/cleanup,
Devang Patelf729e912011-05-31 18:06:14 +0000[diff] [blame]205 tail duplication, etc).</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]206
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]207 <li>LLVM debug information is automatically optimized along with the rest of
208 the program, using existing facilities. For example, duplicate
209 information is automatically merged by the linker, and unused information
210 is automatically removed.</li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]211</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]212
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]213<p>Basically, the debug information allows you to compile a program with
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]214 "<tt>-O0 -g</tt>" and get full debug information, allowing you to arbitrarily
215 modify the program as it executes from a debugger. Compiling a program with
216 "<tt>-O3 -g</tt>" gives you full debug information that is always available
217 and accurate for reading (e.g., you get accurate stack traces despite tail
218 call elimination and inlining), but you might lose the ability to modify the
219 program and call functions where were optimized out of the program, or
220 inlined away completely.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]221
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]222<p><a href="TestingGuide.html#quicktestsuite">LLVM test suite</a> provides a
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]223 framework to test optimizer's handling of debugging information. It can be
224 run like this:</p>
Devang Patela5c05aa2008-11-21 19:35:57 +0000[diff] [blame]225
226<div class="doc_code">
227<pre>
228% cd llvm/projects/test-suite/MultiSource/Benchmarks # or some other level
229% make TEST=dbgopt
230</pre>
231</div>
232
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]233<p>This will test impact of debugging information on optimization passes. If
234 debugging information influences optimization passes then it will be reported
235 as a failure. See <a href="TestingGuide.html">TestingGuide</a> for more
236 information on LLVM test infrastructure and how to run various tests.</p>
Devang Patela5c05aa2008-11-21 19:35:57 +0000[diff] [blame]237
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]238</div>
239
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]240</div>
241
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]242<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]243<h2>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]244 <a name="format">Debugging information format</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]245</h2>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]246<!-- *********************************************************************** -->
247
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]248<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]249
250<p>LLVM debugging information has been carefully designed to make it possible
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]251 for the optimizer to optimize the program and debugging information without
252 necessarily having to know anything about debugging information. In
John Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]253 particular, the use of metadata avoids duplicated debugging information from
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]254 the beginning, and the global dead code elimination pass automatically
255 deletes debugging information for a function if it decides to delete the
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]256 function. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]257
258<p>To do this, most of the debugging information (descriptors for types,
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]259 variables, functions, source files, etc) is inserted by the language
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]260 front-end in the form of LLVM metadata. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]261
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]262<p>Debug information is designed to be agnostic about the target debugger and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]263 debugging information representation (e.g. DWARF/Stabs/etc). It uses a
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]264 generic pass to decode the information that represents variables, types,
265 functions, namespaces, etc: this allows for arbitrary source-language
266 semantics and type-systems to be used, as long as there is a module
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]267 written for the target debugger to interpret the information. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]268
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]269<p>To provide basic functionality, the LLVM debugger does have to make some
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]270 assumptions about the source-level language being debugged, though it keeps
271 these to a minimum. The only common features that the LLVM debugger assumes
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]272 exist are <a href="#format_files">source files</a>,
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]273 and <a href="#format_global_variables">program objects</a>. These abstract
274 objects are used by a debugger to form stack traces, show information about
275 local variables, etc.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]276
277<p>This section of the documentation first describes the representation aspects
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]278 common to any source-language. The <a href="#ccxx_frontend">next section</a>
279 describes the data layout conventions used by the C and C++ front-ends.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]280
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]281<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]282<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]283 <a name="debug_info_descriptors">Debug information descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]284</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]285
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]286<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]287
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]288<p>In consideration of the complexity and volume of debug information, LLVM
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]289 provides a specification for well formed debug descriptors. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]290
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]291<p>Consumers of LLVM debug information expect the descriptors for program
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]292 objects to start in a canonical format, but the descriptors can include
293 additional information appended at the end that is source-language
294 specific. All LLVM debugging information is versioned, allowing backwards
295 compatibility in the case that the core structures need to change in some
296 way. Also, all debugging information objects start with a tag to indicate
297 what type of object it is. The source-language is allowed to define its own
298 objects, by using unreserved tag numbers. We recommend using with tags in
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]299 the range 0x1000 through 0x2000 (there is a defined enum DW_TAG_user_base =
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]300 0x1000.)</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]301
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]302<p>The fields of debug descriptors used internally by LLVM
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]303 are restricted to only the simple data types <tt>i32</tt>, <tt>i1</tt>,
304 <tt>float</tt>, <tt>double</tt>, <tt>mdstring</tt> and <tt>mdnode</tt>. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]305
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]306<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]307<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]308!1 = metadata !{
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]309 i32, ;; A tag
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]310 ...
311}
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]312</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]313</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]314
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]315<p><a name="LLVMDebugVersion">The first field of a descriptor is always an
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]316 <tt>i32</tt> containing a tag value identifying the content of the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]317 descriptor. The remaining fields are specific to the descriptor. The values
318 of tags are loosely bound to the tag values of DWARF information entries.
319 However, that does not restrict the use of the information supplied to DWARF
320 targets. To facilitate versioning of debug information, the tag is augmented
Nick Lewyckyf3379da2011-07-25 21:13:23 +0000[diff] [blame]321 with the current debug version (LLVMDebugVersion = 8 &lt;&lt; 16 or
322 0x80000 or 524288.)</a></p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]323
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]324<p>The details of the various descriptors follow.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]325
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]326<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]327<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]328 <a name="format_compile_units">Compile unit descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]329</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]330
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]331<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]332
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]333<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]334<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]335!0 = metadata !{
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]336 i32, ;; Tag = 17 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]337 ;; (DW_TAG_compile_unit)
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]338 i32, ;; Unused field.
339 i32, ;; DWARF language identifier (ex. DW_LANG_C89)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]340 metadata, ;; Source file name
341 metadata, ;; Source file directory (includes trailing slash)
342 metadata ;; Producer (ex. "4.0.1 LLVM (LLVM research group)")
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]343 i1, ;; True if this is a main compile unit.
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]344 i1, ;; True if this is optimized.
345 metadata, ;; Flags
346 i32 ;; Runtime version
Devang Patel9b4a2ac2011-09-09 17:07:15 +0000[diff] [blame]347 metadata ;; List of enums types
348 metadata ;; List of retained types
349 metadata ;; List of subprograms
350 metadata ;; List of global variables
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]351}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]352</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]353</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]354
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]355<p>These descriptors contain a source language ID for the file (we use the DWARF
356 3.0 ID numbers, such as <tt>DW_LANG_C89</tt>, <tt>DW_LANG_C_plus_plus</tt>,
357 <tt>DW_LANG_Cobol74</tt>, etc), three strings describing the filename,
358 working directory of the compiler, and an identifier string for the compiler
359 that produced it.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]360
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]361<p>Compile unit descriptors provide the root context for objects declared in a
Devang Patel464f4ef2011-05-03 16:18:28 +0000[diff] [blame]362 specific compilation unit. File descriptors are defined using this context.
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]363 These descriptors are collected by a named metadata
Devang Patel9b4a2ac2011-09-09 17:07:15 +0000[diff] [blame]364 <tt>!llvm.dbg.cu</tt>. Compile unit descriptor keeps track of subprograms,
365 global variables and type information.
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]366
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]367</div>
368
369<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]370<h4>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]371 <a name="format_files">File descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]372</h4>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]373
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]374<div>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]375
376<div class="doc_code">
377<pre>
378!0 = metadata !{
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]379 i32, ;; Tag = 41 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]380 ;; (DW_TAG_file_type)
381 metadata, ;; Source file name
382 metadata, ;; Source file directory (includes trailing slash)
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]383 metadata ;; Unused
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]384}
385</pre>
386</div>
387
John Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]388<p>These descriptors contain information for a file. Global variables and top
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]389 level functions would be defined using this context.k File descriptors also
390 provide context for source line correspondence. </p>
391
392<p>Each input file is encoded as a separate file descriptor in LLVM debugging
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]393 information output. </p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]394
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]395</div>
396
397<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]398<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]399 <a name="format_global_variables">Global variable descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]400</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]401
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]402<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]403
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]404<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]405<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]406!1 = metadata !{
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]407 i32, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]408 ;; (DW_TAG_variable)
409 i32, ;; Unused field.
410 metadata, ;; Reference to context descriptor
411 metadata, ;; Name
412 metadata, ;; Display name (fully qualified C++ name)
413 metadata, ;; MIPS linkage name (for C++)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]414 metadata, ;; Reference to file where defined
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]415 i32, ;; Line number where defined
416 metadata, ;; Reference to type descriptor
417 i1, ;; True if the global is local to compile unit (static)
418 i1, ;; True if the global is defined in the compile unit (not extern)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]419 {}* ;; Reference to the global variable
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]420}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]421</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]422</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]423
424<p>These descriptors provide debug information about globals variables. The
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]425provide details such as name, type and where the variable is defined. All
426global variables are collected by named metadata <tt>!llvm.dbg.gv</tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]427
428</div>
429
430<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]431<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]432 <a name="format_subprograms">Subprogram descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]433</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]434
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]435<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]436
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]437<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]438<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]439!2 = metadata !{
440 i32, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
441 ;; (DW_TAG_subprogram)
442 i32, ;; Unused field.
443 metadata, ;; Reference to context descriptor
444 metadata, ;; Name
445 metadata, ;; Display name (fully qualified C++ name)
446 metadata, ;; MIPS linkage name (for C++)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]447 metadata, ;; Reference to file where defined
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]448 i32, ;; Line number where defined
449 metadata, ;; Reference to type descriptor
450 i1, ;; True if the global is local to compile unit (static)
Devang Patel5e06bb82011-04-22 23:10:17 +0000[diff] [blame]451 i1, ;; True if the global is defined in the compile unit (not extern)
452 i32, ;; Virtuality, e.g. dwarf::DW_VIRTUALITY__virtual
453 i32, ;; Index into a virtual function
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]454 metadata, ;; indicates which base type contains the vtable pointer for the
Devang Patel80ecc152010-06-04 22:49:55 +0000[diff] [blame]455 ;; derived class
Devang Patel473f95f2011-12-16 17:50:04 +0000[diff] [blame]456 i32, ;; Flags - Artifical, Private, Protected, Explicit, Prototyped.
Devang Patel5e06bb82011-04-22 23:10:17 +0000[diff] [blame]457 i1, ;; isOptimized
458 Function *,;; Pointer to LLVM function
459 metadata, ;; Lists function template parameters
460 metadata ;; Function declaration descriptor
Devang Patel93d39be2011-08-19 23:28:12 +0000[diff] [blame]461 metadata ;; List of function variables
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]462}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]463</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]464</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]465
466<p>These descriptors provide debug information about functions, methods and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]467 subprograms. They provide details such as name, return types and the source
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]468 location where the subprogram is defined.
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]469</p>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]470
471</div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]472
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]473<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]474<h4>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]475 <a name="format_blocks">Block descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]476</h4>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]477
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]478<div>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]479
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]480<div class="doc_code">
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]481<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]482!3 = metadata !{
Devang Patelc79dda22010-10-04 16:51:59 +0000[diff] [blame]483 i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
Devang Patel7f271fc2010-10-01 22:45:00 +0000[diff] [blame]484 metadata,;; Reference to context descriptor
485 i32, ;; Line number
Devang Patel90d81f12011-03-08 16:25:29 +0000[diff] [blame]486 i32, ;; Column number
487 metadata,;; Reference to source file
488 i32 ;; Unique ID to identify blocks from a template function
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]489}
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]490</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]491</div>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]492
Eric Christopher6618a242011-10-11 22:59:11 +0000[diff] [blame]493<p>This descriptor provides debug information about nested blocks within a
Devang Patel7f271fc2010-10-01 22:45:00 +0000[diff] [blame]494 subprogram. The line number and column numbers are used to dinstinguish
495 two lexical blocks at same depth. </p>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]496
Eric Christopher6618a242011-10-11 22:59:11 +0000[diff] [blame]497<div class="doc_code">
498<pre>
499!3 = metadata !{
500 i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
501 metadata ;; Reference to the scope we're annotating with a file change
502 metadata,;; Reference to the file the scope is enclosed in.
503}
504</pre>
505</div>
506
507<p>This descriptor provides a wrapper around a lexical scope to handle file
508 changes in the middle of a lexical block.</p>
509
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]510</div>
511
512<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]513<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]514 <a name="format_basic_type">Basic type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]515</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]516
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]517<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]518
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]519<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]520<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]521!4 = metadata !{
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]522 i32, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]523 ;; (DW_TAG_base_type)
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]524 metadata, ;; Reference to context
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]525 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]526 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]527 i32, ;; Line number where defined (may be 0)
528 i64, ;; Size in bits
529 i64, ;; Alignment in bits
530 i64, ;; Offset in bits
531 i32, ;; Flags
532 i32 ;; DWARF type encoding
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]533}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]534</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]535</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]536
537<p>These descriptors define primitive types used in the code. Example int, bool
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]538 and float. The context provides the scope of the type, which is usually the
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]539 top level. Since basic types are not usually user defined the context
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]540 and line number can be left as NULL and 0. The size, alignment and offset
541 are expressed in bits and can be 64 bit values. The alignment is used to
542 round the offset when embedded in a
543 <a href="#format_composite_type">composite type</a> (example to keep float
544 doubles on 64 bit boundaries.) The offset is the bit offset if embedded in
545 a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]546
547<p>The type encoding provides the details of the type. The values are typically
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]548 one of the following:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]549
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]550<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]551<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]552DW_ATE_address = 1
553DW_ATE_boolean = 2
554DW_ATE_float = 4
555DW_ATE_signed = 5
556DW_ATE_signed_char = 6
557DW_ATE_unsigned = 7
558DW_ATE_unsigned_char = 8
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]559</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]560</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]561
562</div>
563
564<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]565<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]566 <a name="format_derived_type">Derived type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]567</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]568
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]569<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]570
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]571<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]572<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]573!5 = metadata !{
574 i32, ;; Tag (see below)
575 metadata, ;; Reference to context
576 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]577 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]578 i32, ;; Line number where defined (may be 0)
Devang Patel0ffd10b2010-10-01 19:19:30 +0000[diff] [blame]579 i64, ;; Size in bits
580 i64, ;; Alignment in bits
581 i64, ;; Offset in bits
Eric Christopher402e12a2011-12-16 23:42:33 +0000[diff] [blame]582 i32, ;; Flags to encode attributes, e.g. private
Devang Patele9db5e22011-04-16 00:11:51 +0000[diff] [blame]583 metadata, ;; Reference to type derived from
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]584 metadata, ;; (optional) Name of the Objective C property associated with
585 ;; Objective-C an ivar
Devang Patele9db5e22011-04-16 00:11:51 +0000[diff] [blame]586 metadata, ;; (optional) Name of the Objective C property getter selector.
587 metadata, ;; (optional) Name of the Objective C property setter selector.
588 i32 ;; (optional) Objective C property attributes.
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]589}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]590</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]591</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]592
593<p>These descriptors are used to define types derived from other types. The
594value of the tag varies depending on the meaning. The following are possible
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]595tag values:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]596
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]597<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]598<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]599DW_TAG_formal_parameter = 5
600DW_TAG_member = 13
601DW_TAG_pointer_type = 15
602DW_TAG_reference_type = 16
603DW_TAG_typedef = 22
604DW_TAG_const_type = 38
605DW_TAG_volatile_type = 53
606DW_TAG_restrict_type = 55
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]607</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]608</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]609
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]610<p><tt>DW_TAG_member</tt> is used to define a member of
611 a <a href="#format_composite_type">composite type</a>
612 or <a href="#format_subprograms">subprogram</a>. The type of the member is
613 the <a href="#format_derived_type">derived
614 type</a>. <tt>DW_TAG_formal_parameter</tt> is used to define a member which
615 is a formal argument of a subprogram.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]616
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]617<p><tt>DW_TAG_typedef</tt> is used to provide a name for the derived type.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]618
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]619<p><tt>DW_TAG_pointer_type</tt>, <tt>DW_TAG_reference_type</tt>,
620 <tt>DW_TAG_const_type</tt>, <tt>DW_TAG_volatile_type</tt> and
Eric Christopheradfc1ef2011-12-16 23:42:35 +0000[diff] [blame]621 <tt>DW_TAG_restrict_type</tt> are used to qualify
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]622 the <a href="#format_derived_type">derived type</a>. </p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]623
624<p><a href="#format_derived_type">Derived type</a> location can be determined
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]625 from the context and line number. The size, alignment and offset are
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]626 expressed in bits and can be 64 bit values. The alignment is used to round
627 the offset when embedded in a <a href="#format_composite_type">composite
628 type</a> (example to keep float doubles on 64 bit boundaries.) The offset is
629 the bit offset if embedded in a <a href="#format_composite_type">composite
630 type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]631
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]632<p>Note that the <tt>void *</tt> type is expressed as a type derived from NULL.
633</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]634
635</div>
636
637<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]638<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]639 <a name="format_composite_type">Composite type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]640</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]641
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]642<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]643
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]644<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]645<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]646!6 = metadata !{
647 i32, ;; Tag (see below)
648 metadata, ;; Reference to context
649 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]650 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]651 i32, ;; Line number where defined (may be 0)
652 i64, ;; Size in bits
653 i64, ;; Alignment in bits
654 i64, ;; Offset in bits
655 i32, ;; Flags
656 metadata, ;; Reference to type derived from
657 metadata, ;; Reference to array of member descriptors
658 i32 ;; Runtime languages
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]659}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]660</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]661</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]662
663<p>These descriptors are used to define types that are composed of 0 or more
664elements. The value of the tag varies depending on the meaning. The following
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]665are possible tag values:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]666
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]667<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]668<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]669DW_TAG_array_type = 1
670DW_TAG_enumeration_type = 4
671DW_TAG_structure_type = 19
672DW_TAG_union_type = 23
673DW_TAG_vector_type = 259
Bruno Cardoso Lopesd80ddc02009-05-29 17:08:57 +0000[diff] [blame]674DW_TAG_subroutine_type = 21
675DW_TAG_inheritance = 28
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]676</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]677</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]678
Jim Laskeyf8a01a92006-06-15 20:51:43 +0000[diff] [blame]679<p>The vector flag indicates that an array type is a native packed vector.</p>
680
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]681<p>The members of array types (tag = <tt>DW_TAG_array_type</tt>) or vector types
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]682 (tag = <tt>DW_TAG_vector_type</tt>) are <a href="#format_subrange">subrange
683 descriptors</a>, each representing the range of subscripts at that level of
684 indexing.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]685
686<p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]687 <a href="#format_enumeration">enumerator descriptors</a>, each representing
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]688 the definition of enumeration value for the set. All enumeration type
689 descriptors are collected by named metadata <tt>!llvm.dbg.enum</tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]690
691<p>The members of structure (tag = <tt>DW_TAG_structure_type</tt>) or union (tag
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]692 = <tt>DW_TAG_union_type</tt>) types are any one of
693 the <a href="#format_basic_type">basic</a>,
694 <a href="#format_derived_type">derived</a>
695 or <a href="#format_composite_type">composite</a> type descriptors, each
696 representing a field member of the structure or union.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]697
Jim Laskey4a9df242006-08-21 21:21:06 +0000[diff] [blame]698<p>For C++ classes (tag = <tt>DW_TAG_structure_type</tt>), member descriptors
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]699 provide information about base classes, static members and member
700 functions. If a member is a <a href="#format_derived_type">derived type
701 descriptor</a> and has a tag of <tt>DW_TAG_inheritance</tt>, then the type
702 represents a base class. If the member of is
703 a <a href="#format_global_variables">global variable descriptor</a> then it
704 represents a static member. And, if the member is
705 a <a href="#format_subprograms">subprogram descriptor</a> then it represents
706 a member function. For static members and member
707 functions, <tt>getName()</tt> returns the members link or the C++ mangled
708 name. <tt>getDisplayName()</tt> the simplied version of the name.</p>
Jim Laskey4a9df242006-08-21 21:21:06 +0000[diff] [blame]709
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]710<p>The first member of subroutine (tag = <tt>DW_TAG_subroutine_type</tt>) type
711 elements is the return type for the subroutine. The remaining elements are
712 the formal arguments to the subroutine.</p>
Jim Laskey094ee722006-06-20 21:13:20 +0000[diff] [blame]713
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]714<p><a href="#format_composite_type">Composite type</a> location can be
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]715 determined from the context and line number. The size, alignment and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]716 offset are expressed in bits and can be 64 bit values. The alignment is used
717 to round the offset when embedded in
718 a <a href="#format_composite_type">composite type</a> (as an example, to keep
719 float doubles on 64 bit boundaries.) The offset is the bit offset if embedded
720 in a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]721
722</div>
723
724<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]725<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]726 <a name="format_subrange">Subrange descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]727</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]728
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]729<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]730
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]731<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]732<pre>
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]733!42 = metadata !{
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]734 i32, ;; Tag = 33 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subrange_type)
735 i64, ;; Low value
736 i64 ;; High value
737}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]738</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]739</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]740
741<p>These descriptors are used to define ranges of array subscripts for an array
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]742 <a href="#format_composite_type">composite type</a>. The low value defines
743 the lower bounds typically zero for C/C++. The high value is the upper
744 bounds. Values are 64 bit. High - low + 1 is the size of the array. If low
Devang Patel3f932a72011-04-08 23:39:38 +0000[diff] [blame]745 > high the array bounds are not included in generated debugging information.
746</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]747
748</div>
749
750<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]751<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]752 <a name="format_enumeration">Enumerator descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]753</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]754
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]755<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]756
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]757<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]758<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]759!6 = metadata !{
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]760 i32, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]761 ;; (DW_TAG_enumerator)
762 metadata, ;; Name
763 i64 ;; Value
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]764}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]765</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]766</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]767
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]768<p>These descriptors are used to define members of an
769 enumeration <a href="#format_composite_type">composite type</a>, it
770 associates the name to the value.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]771
772</div>
773
774<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]775<h4>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]776 <a name="format_variables">Local variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]777</h4>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]778
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]779<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]780
781<div class="doc_code">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]782<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]783!7 = metadata !{
784 i32, ;; Tag (see below)
785 metadata, ;; Context
786 metadata, ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]787 metadata, ;; Reference to file where defined
Devang Patela83688f2011-03-08 16:29:40 +0000[diff] [blame]788 i32, ;; 24 bit - Line number where defined
789 ;; 8 bit - Argument number. 1 indicates 1st argument.
Devang Patel0a2a3062011-07-27 18:14:50 +0000[diff] [blame]790 metadata, ;; Type descriptor
791 i32, ;; flags
792 metadata ;; (optional) Reference to inline location
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]793}
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]794</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]795</div>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]796
797<p>These descriptors are used to define variables local to a sub program. The
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]798 value of the tag depends on the usage of the variable:</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]799
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]800<div class="doc_code">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]801<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]802DW_TAG_auto_variable = 256
803DW_TAG_arg_variable = 257
804DW_TAG_return_variable = 258
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]805</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]806</div>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]807
808<p>An auto variable is any variable declared in the body of the function. An
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]809 argument variable is any variable that appears as a formal argument to the
810 function. A return variable is used to track the result of a function and
811 has no source correspondent.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]812
Jim Laskey2d395d92006-03-24 09:20:27 +0000[diff] [blame]813<p>The context is either the subprogram or block where the variable is defined.
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]814 Name the source variable name. Context and line indicate where the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]815 variable was defined. Type descriptor defines the declared type of the
816 variable.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]817
818</div>
819
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]820</div>
821
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]822<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]823<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]824 <a name="format_common_intrinsics">Debugger intrinsic functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]825</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]826
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]827<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]828
829<p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]830 provide debug information at various points in generated code.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]831
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]832<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]833<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]834 <a name="format_common_declare">llvm.dbg.declare</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]835</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]836
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]837<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]838<pre>
Devang Patel4c7c0c62010-10-01 19:22:16 +0000[diff] [blame]839 void %<a href="#format_common_declare">llvm.dbg.declare</a>(metadata, metadata)
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]840</pre>
841
Chad Rosier5bfd9692012-02-18 01:38:41 +0000[diff] [blame]842<p>This intrinsic provides information about a local element (e.g., variable). The
843 first argument is metadata holding the alloca for the variable. The
844 second argument is metadata containing a description of the variable.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]845</div>
846
847<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]848<h4>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]849 <a name="format_common_value">llvm.dbg.value</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]850</h4>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]851
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]852<div>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]853<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]854 void %<a href="#format_common_value">llvm.dbg.value</a>(metadata, i64, metadata)
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]855</pre>
856
857<p>This intrinsic provides information when a user source variable is set to a
858 new value. The first argument is the new value (wrapped as metadata). The
859 second argument is the offset in the user source variable where the new value
Chad Rosier5bfd9692012-02-18 01:38:41 +0000[diff] [blame]860 is written. The third argument is metadata containing a description of the
861 user source variable.</p>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]862</div>
863
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]864</div>
865
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]866<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]867<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]868 <a name="format_common_lifetime">Object lifetimes and scoping</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]869</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]870
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]871<div>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]872<p>In many languages, the local variables in functions can have their lifetimes
873 or scopes limited to a subset of a function. In the C family of languages,
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]874 for example, variables are only live (readable and writable) within the
875 source block that they are defined in. In functional languages, values are
876 only readable after they have been defined. Though this is a very obvious
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]877 concept, it is non-trivial to model in LLVM, because it has no notion of
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]878 scoping in this sense, and does not want to be tied to a language's scoping
879 rules.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]880
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]881<p>In order to handle this, the LLVM debug format uses the metadata attached to
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]882 llvm instructions to encode line number and scoping information. Consider
883 the following C fragment, for example:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]884
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]885<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]886<pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8871. void foo() {
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8882. int X = 21;
8893. int Y = 22;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8904. {
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8915. int Z = 23;
8926. Z = X;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8937. }
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8948. X = Y;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8959. }
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]896</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]897</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]898
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]899<p>Compiled to LLVM, this function would be represented like this:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]900
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]901<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]902<pre>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]903define void @foo() nounwind ssp {
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]904entry:
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]905 %X = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
906 %Y = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
907 %Z = alloca i32, align 4 ; &lt;i32*&gt; [#uses=3]
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]908 %0 = bitcast i32* %X to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]909 call void @llvm.dbg.declare(metadata !{i32 * %X}, metadata !0), !dbg !7
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]910 store i32 21, i32* %X, !dbg !8
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]911 %1 = bitcast i32* %Y to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]912 call void @llvm.dbg.declare(metadata !{i32 * %Y}, metadata !9), !dbg !10
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]913 store i32 22, i32* %Y, !dbg !11
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]914 %2 = bitcast i32* %Z to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]915 call void @llvm.dbg.declare(metadata !{i32 * %Z}, metadata !12), !dbg !14
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]916 store i32 23, i32* %Z, !dbg !15
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]917 %tmp = load i32* %X, !dbg !16 ; &lt;i32&gt; [#uses=1]
918 %tmp1 = load i32* %Y, !dbg !16 ; &lt;i32&gt; [#uses=1]
919 %add = add nsw i32 %tmp, %tmp1, !dbg !16 ; &lt;i32&gt; [#uses=1]
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]920 store i32 %add, i32* %Z, !dbg !16
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]921 %tmp2 = load i32* %Y, !dbg !17 ; &lt;i32&gt; [#uses=1]
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]922 store i32 %tmp2, i32* %X, !dbg !17
923 ret void, !dbg !18
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]924}
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]925
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]926declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]927
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]928!0 = metadata !{i32 459008, metadata !1, metadata !"X",
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]929 metadata !3, i32 2, metadata !6}; [ DW_TAG_auto_variable ]
930!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]931!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo", metadata !"foo",
932 metadata !"foo", metadata !3, i32 1, metadata !4,
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]933 i1 false, i1 true}; [DW_TAG_subprogram ]
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]934!3 = metadata !{i32 458769, i32 0, i32 12, metadata !"foo.c",
935 metadata !"/private/tmp", metadata !"clang 1.1", i1 true,
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]936 i1 false, metadata !"", i32 0}; [DW_TAG_compile_unit ]
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]937!4 = metadata !{i32 458773, metadata !3, metadata !"", null, i32 0, i64 0, i64 0,
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]938 i64 0, i32 0, null, metadata !5, i32 0}; [DW_TAG_subroutine_type ]
939!5 = metadata !{null}
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]940!6 = metadata !{i32 458788, metadata !3, metadata !"int", metadata !3, i32 0,
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]941 i64 32, i64 32, i64 0, i32 0, i32 5}; [DW_TAG_base_type ]
942!7 = metadata !{i32 2, i32 7, metadata !1, null}
943!8 = metadata !{i32 2, i32 3, metadata !1, null}
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]944!9 = metadata !{i32 459008, metadata !1, metadata !"Y", metadata !3, i32 3,
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]945 metadata !6}; [ DW_TAG_auto_variable ]
946!10 = metadata !{i32 3, i32 7, metadata !1, null}
947!11 = metadata !{i32 3, i32 3, metadata !1, null}
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]948!12 = metadata !{i32 459008, metadata !13, metadata !"Z", metadata !3, i32 5,
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]949 metadata !6}; [ DW_TAG_auto_variable ]
950!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
951!14 = metadata !{i32 5, i32 9, metadata !13, null}
952!15 = metadata !{i32 5, i32 5, metadata !13, null}
953!16 = metadata !{i32 6, i32 5, metadata !13, null}
954!17 = metadata !{i32 8, i32 3, metadata !1, null}
955!18 = metadata !{i32 9, i32 1, metadata !2, null}
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]956</pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]957</div>
958
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]959<p>This example illustrates a few important details about LLVM debugging
960 information. In particular, it shows how the <tt>llvm.dbg.declare</tt>
961 intrinsic and location information, which are attached to an instruction,
962 are applied together to allow a debugger to analyze the relationship between
963 statements, variable definitions, and the code used to implement the
964 function.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]965
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]966<div class="doc_code">
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]967<pre>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]968call void @llvm.dbg.declare(metadata, metadata !0), !dbg !7
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]969</pre>
970</div>
971
972<p>The first intrinsic
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]973 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]974 encodes debugging information for the variable <tt>X</tt>. The metadata
975 <tt>!dbg !7</tt> attached to the intrinsic provides scope information for the
976 variable <tt>X</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]977
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]978<div class="doc_code">
979<pre>
980!7 = metadata !{i32 2, i32 7, metadata !1, null}
981!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]982!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo",
983 metadata !"foo", metadata !"foo", metadata !3, i32 1,
984 metadata !4, i1 false, i1 true}; [DW_TAG_subprogram ]
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]985</pre>
986</div>
987
988<p>Here <tt>!7</tt> is metadata providing location information. It has four
989 fields: line number, column number, scope, and original scope. The original
990 scope represents inline location if this instruction is inlined inside a
991 caller, and is null otherwise. In this example, scope is encoded by
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]992 <tt>!1</tt>. <tt>!1</tt> represents a lexical block inside the scope
993 <tt>!2</tt>, where <tt>!2</tt> is a
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]994 <a href="#format_subprograms">subprogram descriptor</a>. This way the
995 location information attached to the intrinsics indicates that the
996 variable <tt>X</tt> is declared at line number 2 at a function level scope in
997 function <tt>foo</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]998
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]999<p>Now lets take another example.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1000
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]1001<div class="doc_code">
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]1002<pre>
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]1003call void @llvm.dbg.declare(metadata, metadata !12), !dbg !14
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]1004</pre>
1005</div>
1006
1007<p>The second intrinsic
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]1008 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1009 encodes debugging information for variable <tt>Z</tt>. The metadata
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]1010 <tt>!dbg !14</tt> attached to the intrinsic provides scope information for
1011 the variable <tt>Z</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1012
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]1013<div class="doc_code">
1014<pre>
1015!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
1016!14 = metadata !{i32 5, i32 9, metadata !13, null}
1017</pre>
1018</div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1019
John Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]1020<p>Here <tt>!14</tt> indicates that <tt>Z</tt> is declared at line number 5 and
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]1021 column number 9 inside of lexical scope <tt>!13</tt>. The lexical scope
1022 itself resides inside of lexical scope <tt>!1</tt> described above.</p>
1023
1024<p>The scope information attached with each instruction provides a
1025 straightforward way to find instructions covered by a scope.</p>
1026
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1027</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1028
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1029</div>
1030
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1031<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1032<h2>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1033 <a name="ccxx_frontend">C/C++ front-end specific debug information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1034</h2>
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]1035<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1036
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1037<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1038
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1039<p>The C and C++ front-ends represent information about the program in a format
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1040 that is effectively identical
1041 to <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3.0</a> in
1042 terms of information content. This allows code generators to trivially
1043 support native debuggers by generating standard dwarf information, and
1044 contains enough information for non-dwarf targets to translate it as
1045 needed.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1046
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1047<p>This section describes the forms used to represent C and C++ programs. Other
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1048 languages could pattern themselves after this (which itself is tuned to
1049 representing programs in the same way that DWARF 3 does), or they could
1050 choose to provide completely different forms if they don't fit into the DWARF
1051 model. As support for debugging information gets added to the various LLVM
1052 source-language front-ends, the information used should be documented
1053 here.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1054
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1055<p>The following sections provide examples of various C/C++ constructs and the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1056 debug information that would best describe those constructs.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1057
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1058<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1059<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1060 <a name="ccxx_compile_units">C/C++ source file information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1061</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1062
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1063<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1064
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1065<p>Given the source files <tt>MySource.cpp</tt> and <tt>MyHeader.h</tt> located
1066 in the directory <tt>/Users/mine/sources</tt>, the following code:</p>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1067
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1068<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1069<pre>
1070#include "MyHeader.h"
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1071
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1072int main(int argc, char *argv[]) {
1073 return 0;
1074}
1075</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1076</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1077
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1078<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1079
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1080<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1081<pre>
1082...
1083;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1084;; Define the compile unit for the main source file "/Users/mine/sources/MySource.cpp".
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1085;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1086!2 = metadata !{
1087 i32 524305, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1088 i32 0, ;; Unused
1089 i32 4, ;; Language Id
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1090 metadata !"MySource.cpp",
1091 metadata !"/Users/mine/sources",
1092 metadata !"4.2.1 (Based on Apple Inc. build 5649) (LLVM build 00)",
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1093 i1 true, ;; Main Compile Unit
1094 i1 false, ;; Optimized compile unit
1095 metadata !"", ;; Compiler flags
1096 i32 0} ;; Runtime version
1097
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1098;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1099;; Define the file for the file "/Users/mine/sources/MySource.cpp".
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1100;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1101!1 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1102 i32 524329, ;; Tag
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1103 metadata !"MySource.cpp",
1104 metadata !"/Users/mine/sources",
Devang Patel9fea9c22010-07-13 16:53:20 +0000[diff] [blame]1105 metadata !2 ;; Compile unit
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1106}
1107
1108;;
1109;; Define the file for the file "/Users/mine/sources/Myheader.h"
1110;;
1111!3 = metadata !{
1112 i32 524329, ;; Tag
1113 metadata !"Myheader.h"
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1114 metadata !"/Users/mine/sources",
Devang Patel9fea9c22010-07-13 16:53:20 +0000[diff] [blame]1115 metadata !2 ;; Compile unit
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1116}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1117
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1118...
1119</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1120</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1121
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1122<p>llvm::Instruction provides easy access to metadata attached with an
Devang Pateld98ec5f2010-03-26 19:08:36 +0000[diff] [blame]1123instruction. One can extract line number information encoded in LLVM IR
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1124using <tt>Instruction::getMetadata()</tt> and
Devang Pateld98ec5f2010-03-26 19:08:36 +0000[diff] [blame]1125<tt>DILocation::getLineNumber()</tt>.
1126<pre>
1127 if (MDNode *N = I->getMetadata("dbg")) { // Here I is an LLVM instruction
1128 DILocation Loc(N); // DILocation is in DebugInfo.h
1129 unsigned Line = Loc.getLineNumber();
1130 StringRef File = Loc.getFilename();
1131 StringRef Dir = Loc.getDirectory();
1132 }
1133</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1134</div>
1135
1136<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1137<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1138 <a name="ccxx_global_variable">C/C++ global variable information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1139</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1140
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1141<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1142
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1143<p>Given an integer global variable declared as follows:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1144
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1145<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1146<pre>
1147int MyGlobal = 100;
1148</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1149</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1150
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1151<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1152
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1153<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1154<pre>
1155;;
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1156;; Define the global itself.
1157;;
1158%MyGlobal = global int 100
1159...
1160;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1161;; List of debug info of globals
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1162;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1163!llvm.dbg.gv = !{!0}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1164
1165;;
1166;; Define the global variable descriptor. Note the reference to the global
1167;; variable anchor and the global variable itself.
1168;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1169!0 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1170 i32 524340, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1171 i32 0, ;; Unused
1172 metadata !1, ;; Context
1173 metadata !"MyGlobal", ;; Name
1174 metadata !"MyGlobal", ;; Display Name
1175 metadata !"MyGlobal", ;; Linkage Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1176 metadata !3, ;; Compile Unit
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1177 i32 1, ;; Line Number
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1178 metadata !4, ;; Type
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1179 i1 false, ;; Is a local variable
1180 i1 true, ;; Is this a definition
1181 i32* @MyGlobal ;; The global variable
1182}
1183
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1184;;
1185;; Define the basic type of 32 bit signed integer. Note that since int is an
1186;; intrinsic type the source file is NULL and line 0.
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1187;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1188!4 = metadata !{
1189 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1190 metadata !1, ;; Context
1191 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1192 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1193 i32 0, ;; Line number
1194 i64 32, ;; Size in Bits
1195 i64 32, ;; Align in Bits
1196 i64 0, ;; Offset in Bits
1197 i32 0, ;; Flags
1198 i32 5 ;; Encoding
1199}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1200
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1201</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1202</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1203
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1204</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1205
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1206<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1207<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1208 <a name="ccxx_subprogram">C/C++ function information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1209</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1210
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1211<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1212
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1213<p>Given a function declared as follows:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1214
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1215<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1216<pre>
1217int main(int argc, char *argv[]) {
1218 return 0;
1219}
1220</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1221</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1222
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1223<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1224
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1225<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1226<pre>
1227;;
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1228;; Define the anchor for subprograms. Note that the second field of the
1229;; anchor is 46, which is the same as the tag for subprograms
1230;; (46 = DW_TAG_subprogram.)
1231;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1232!6 = metadata !{
1233 i32 524334, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1234 i32 0, ;; Unused
1235 metadata !1, ;; Context
1236 metadata !"main", ;; Name
1237 metadata !"main", ;; Display name
1238 metadata !"main", ;; Linkage name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1239 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1240 i32 1, ;; Line number
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1241 metadata !4, ;; Type
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1242 i1 false, ;; Is local
Devang Patelda194752011-04-05 22:52:06 +0000[diff] [blame]1243 i1 true, ;; Is definition
1244 i32 0, ;; Virtuality attribute, e.g. pure virtual function
1245 i32 0, ;; Index into virtual table for C++ methods
1246 i32 0, ;; Type that holds virtual table.
1247 i32 0, ;; Flags
1248 i1 false, ;; True if this function is optimized
1249 Function *, ;; Pointer to llvm::Function
1250 null ;; Function template parameters
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1251}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1252;;
1253;; Define the subprogram itself.
1254;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1255define i32 @main(i32 %argc, i8** %argv) {
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1256...
1257}
1258</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1259</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1260
1261</div>
1262
1263<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1264<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1265 <a name="ccxx_basic_types">C/C++ basic types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1266</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1267
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1268<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1269
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1270<p>The following are the basic type descriptors for C/C++ core types:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1271
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1272<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1273<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1274 <a name="ccxx_basic_type_bool">bool</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1275</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1276
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1277<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1278
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1279<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1280<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1281!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1282 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1283 metadata !1, ;; Context
1284 metadata !"bool", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1285 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1286 i32 0, ;; Line number
1287 i64 8, ;; Size in Bits
1288 i64 8, ;; Align in Bits
1289 i64 0, ;; Offset in Bits
1290 i32 0, ;; Flags
1291 i32 2 ;; Encoding
1292}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1293</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1294</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1295
1296</div>
1297
1298<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1299<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1300 <a name="ccxx_basic_char">char</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1301</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1302
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1303<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1304
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1305<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1306<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1307!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1308 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1309 metadata !1, ;; Context
1310 metadata !"char", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1311 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1312 i32 0, ;; Line number
1313 i64 8, ;; Size in Bits
1314 i64 8, ;; Align in Bits
1315 i64 0, ;; Offset in Bits
1316 i32 0, ;; Flags
1317 i32 6 ;; Encoding
1318}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1319</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1320</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1321
1322</div>
1323
1324<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1325<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1326 <a name="ccxx_basic_unsigned_char">unsigned char</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1327</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1328
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1329<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1330
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1331<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1332<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1333!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1334 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1335 metadata !1, ;; Context
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1336 metadata !"unsigned char",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1337 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1338 i32 0, ;; Line number
1339 i64 8, ;; Size in Bits
1340 i64 8, ;; Align in Bits
1341 i64 0, ;; Offset in Bits
1342 i32 0, ;; Flags
1343 i32 8 ;; Encoding
1344}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1345</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1346</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1347
1348</div>
1349
1350<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1351<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1352 <a name="ccxx_basic_short">short</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1353</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1354
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1355<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1356
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1357<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1358<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1359!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1360 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1361 metadata !1, ;; Context
1362 metadata !"short int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1363 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1364 i32 0, ;; Line number
1365 i64 16, ;; Size in Bits
1366 i64 16, ;; Align in Bits
1367 i64 0, ;; Offset in Bits
1368 i32 0, ;; Flags
1369 i32 5 ;; Encoding
1370}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1371</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1372</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1373
1374</div>
1375
1376<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1377<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1378 <a name="ccxx_basic_unsigned_short">unsigned short</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1379</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1380
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1381<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1382
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1383<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1384<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1385!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1386 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1387 metadata !1, ;; Context
1388 metadata !"short unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1389 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1390 i32 0, ;; Line number
1391 i64 16, ;; Size in Bits
1392 i64 16, ;; Align in Bits
1393 i64 0, ;; Offset in Bits
1394 i32 0, ;; Flags
1395 i32 7 ;; Encoding
1396}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1397</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1398</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1399
1400</div>
1401
1402<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1403<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1404 <a name="ccxx_basic_int">int</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1405</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1406
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1407<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1408
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1409<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1410<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1411!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1412 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1413 metadata !1, ;; Context
1414 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1415 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1416 i32 0, ;; Line number
1417 i64 32, ;; Size in Bits
1418 i64 32, ;; Align in Bits
1419 i64 0, ;; Offset in Bits
1420 i32 0, ;; Flags
1421 i32 5 ;; Encoding
1422}
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1423</pre></div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1424
1425</div>
1426
1427<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1428<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1429 <a name="ccxx_basic_unsigned_int">unsigned int</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1430</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1431
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1432<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1433
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1434<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1435<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1436!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1437 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1438 metadata !1, ;; Context
1439 metadata !"unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1440 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1441 i32 0, ;; Line number
1442 i64 32, ;; Size in Bits
1443 i64 32, ;; Align in Bits
1444 i64 0, ;; Offset in Bits
1445 i32 0, ;; Flags
1446 i32 7 ;; Encoding
1447}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1448</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1449</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1450
1451</div>
1452
1453<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1454<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1455 <a name="ccxx_basic_long_long">long long</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1456</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1457
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1458<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1459
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1460<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1461<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1462!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1463 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1464 metadata !1, ;; Context
1465 metadata !"long long int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1466 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1467 i32 0, ;; Line number
1468 i64 64, ;; Size in Bits
1469 i64 64, ;; Align in Bits
1470 i64 0, ;; Offset in Bits
1471 i32 0, ;; Flags
1472 i32 5 ;; Encoding
1473}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1474</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1475</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1476
1477</div>
1478
1479<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1480<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1481 <a name="ccxx_basic_unsigned_long_long">unsigned long long</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1482</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1483
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1484<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1485
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1486<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1487<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1488!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1489 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1490 metadata !1, ;; Context
1491 metadata !"long long unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1492 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1493 i32 0, ;; Line number
1494 i64 64, ;; Size in Bits
1495 i64 64, ;; Align in Bits
1496 i64 0, ;; Offset in Bits
1497 i32 0, ;; Flags
1498 i32 7 ;; Encoding
1499}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1500</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1501</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1502
1503</div>
1504
1505<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1506<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1507 <a name="ccxx_basic_float">float</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1508</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1509
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1510<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1511
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1512<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1513<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1514!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1515 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1516 metadata !1, ;; Context
1517 metadata !"float",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1518 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1519 i32 0, ;; Line number
1520 i64 32, ;; Size in Bits
1521 i64 32, ;; Align in Bits
1522 i64 0, ;; Offset in Bits
1523 i32 0, ;; Flags
1524 i32 4 ;; Encoding
1525}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1526</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1527</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1528
1529</div>
1530
1531<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1532<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1533 <a name="ccxx_basic_double">double</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1534</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1535
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1536<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1537
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1538<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1539<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1540!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1541 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1542 metadata !1, ;; Context
1543 metadata !"double",;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1544 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1545 i32 0, ;; Line number
1546 i64 64, ;; Size in Bits
1547 i64 64, ;; Align in Bits
1548 i64 0, ;; Offset in Bits
1549 i32 0, ;; Flags
1550 i32 4 ;; Encoding
1551}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1552</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1553</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1554
1555</div>
1556
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1557</div>
1558
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1559<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1560<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1561 <a name="ccxx_derived_types">C/C++ derived types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1562</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1563
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1564<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1565
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1566<p>Given the following as an example of C/C++ derived type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1567
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1568<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1569<pre>
1570typedef const int *IntPtr;
1571</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1572</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1573
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1574<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1575
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1576<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1577<pre>
1578;;
1579;; Define the typedef "IntPtr".
1580;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1581!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1582 i32 524310, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1583 metadata !1, ;; Context
1584 metadata !"IntPtr", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1585 metadata !3, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1586 i32 0, ;; Line number
1587 i64 0, ;; Size in bits
1588 i64 0, ;; Align in bits
1589 i64 0, ;; Offset in bits
1590 i32 0, ;; Flags
1591 metadata !4 ;; Derived From type
1592}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1593
1594;;
1595;; Define the pointer type.
1596;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1597!4 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1598 i32 524303, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1599 metadata !1, ;; Context
1600 metadata !"", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1601 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1602 i32 0, ;; Line number
1603 i64 64, ;; Size in bits
1604 i64 64, ;; Align in bits
1605 i64 0, ;; Offset in bits
1606 i32 0, ;; Flags
1607 metadata !5 ;; Derived From type
1608}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1609;;
1610;; Define the const type.
1611;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1612!5 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1613 i32 524326, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1614 metadata !1, ;; Context
1615 metadata !"", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1616 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1617 i32 0, ;; Line number
1618 i64 32, ;; Size in bits
1619 i64 32, ;; Align in bits
1620 i64 0, ;; Offset in bits
1621 i32 0, ;; Flags
1622 metadata !6 ;; Derived From type
1623}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1624;;
1625;; Define the int type.
1626;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1627!6 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1628 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1629 metadata !1, ;; Context
1630 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1631 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1632 i32 0, ;; Line number
1633 i64 32, ;; Size in bits
1634 i64 32, ;; Align in bits
1635 i64 0, ;; Offset in bits
1636 i32 0, ;; Flags
1637 5 ;; Encoding
1638}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1639</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1640</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1641
1642</div>
1643
1644<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1645<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1646 <a name="ccxx_composite_types">C/C++ struct/union types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1647</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1648
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1649<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1650
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1651<p>Given the following as an example of C/C++ struct type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1652
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1653<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1654<pre>
1655struct Color {
1656 unsigned Red;
1657 unsigned Green;
1658 unsigned Blue;
1659};
1660</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1661</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1662
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1663<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1664
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1665<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1666<pre>
1667;;
1668;; Define basic type for unsigned int.
1669;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1670!5 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1671 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1672 metadata !1, ;; Context
1673 metadata !"unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1674 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1675 i32 0, ;; Line number
1676 i64 32, ;; Size in Bits
1677 i64 32, ;; Align in Bits
1678 i64 0, ;; Offset in Bits
1679 i32 0, ;; Flags
1680 i32 7 ;; Encoding
1681}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1682;;
1683;; Define composite type for struct Color.
1684;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1685!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1686 i32 524307, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1687 metadata !1, ;; Context
1688 metadata !"Color", ;; Name
1689 metadata !1, ;; Compile unit
1690 i32 1, ;; Line number
1691 i64 96, ;; Size in bits
1692 i64 32, ;; Align in bits
1693 i64 0, ;; Offset in bits
1694 i32 0, ;; Flags
1695 null, ;; Derived From
1696 metadata !3, ;; Elements
1697 i32 0 ;; Runtime Language
1698}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1699
1700;;
1701;; Define the Red field.
1702;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1703!4 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1704 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1705 metadata !1, ;; Context
1706 metadata !"Red", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1707 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1708 i32 2, ;; Line number
1709 i64 32, ;; Size in bits
1710 i64 32, ;; Align in bits
1711 i64 0, ;; Offset in bits
1712 i32 0, ;; Flags
1713 metadata !5 ;; Derived From type
1714}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1715
1716;;
1717;; Define the Green field.
1718;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1719!6 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1720 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1721 metadata !1, ;; Context
1722 metadata !"Green", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1723 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1724 i32 3, ;; Line number
1725 i64 32, ;; Size in bits
1726 i64 32, ;; Align in bits
1727 i64 32, ;; Offset in bits
1728 i32 0, ;; Flags
1729 metadata !5 ;; Derived From type
1730}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1731
1732;;
1733;; Define the Blue field.
1734;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1735!7 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1736 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1737 metadata !1, ;; Context
1738 metadata !"Blue", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1739 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1740 i32 4, ;; Line number
1741 i64 32, ;; Size in bits
1742 i64 32, ;; Align in bits
1743 i64 64, ;; Offset in bits
1744 i32 0, ;; Flags
1745 metadata !5 ;; Derived From type
1746}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1747
1748;;
1749;; Define the array of fields used by the composite type Color.
1750;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1751!3 = metadata !{metadata !4, metadata !6, metadata !7}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1752</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1753</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1754
1755</div>
1756
1757<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1758<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1759 <a name="ccxx_enumeration_types">C/C++ enumeration types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1760</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1761
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1762<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1763
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1764<p>Given the following as an example of C/C++ enumeration type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1765
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1766<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1767<pre>
1768enum Trees {
1769 Spruce = 100,
1770 Oak = 200,
1771 Maple = 300
1772};
1773</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1774</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1775
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1776<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1777
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1778<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1779<pre>
1780;;
1781;; Define composite type for enum Trees
1782;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1783!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1784 i32 524292, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1785 metadata !1, ;; Context
1786 metadata !"Trees", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1787 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1788 i32 1, ;; Line number
1789 i64 32, ;; Size in bits
1790 i64 32, ;; Align in bits
1791 i64 0, ;; Offset in bits
1792 i32 0, ;; Flags
1793 null, ;; Derived From type
1794 metadata !3, ;; Elements
1795 i32 0 ;; Runtime language
1796}
Devang Patel2a610c72009-08-25 05:24:07 +0000[diff] [blame]1797
Devang Patel82459882009-08-26 05:01:18 +0000[diff] [blame]1798;;
1799;; Define the array of enumerators used by composite type Trees.
1800;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1801!3 = metadata !{metadata !4, metadata !5, metadata !6}
1802
1803;;
1804;; Define Spruce enumerator.
1805;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1806!4 = metadata !{i32 524328, metadata !"Spruce", i64 100}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1807
1808;;
1809;; Define Oak enumerator.
1810;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1811!5 = metadata !{i32 524328, metadata !"Oak", i64 200}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1812
1813;;
1814;; Define Maple enumerator.
1815;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1816!6 = metadata !{i32 524328, metadata !"Maple", i64 300}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1817
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1818</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1819</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1820
1821</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1822
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1823</div>
1824
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1825
1826<!-- *********************************************************************** -->
1827<h2>
1828 <a name="llvmdwarfextension">Debugging information format</a>
1829</h2>
1830<!-- *********************************************************************** -->
1831<div>
1832<!-- ======================================================================= -->
1833<h3>
1834 <a name="objcproperty">Debugging Information Extension for Objective C
1835Properties</a></li>
1836</h3>
1837<div>
1838<!-- *********************************************************************** -->
1839<h4>
1840 <a name="objcpropertyintroduction">Introduction</a>
1841</h4>
1842<!-- *********************************************************************** -->
1843
1844<div>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1845<p>Objective C provides a simpler way to declare and define accessor methods
1846using declared properties. The language provides features to declare a
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1847property and to let compiler synthesize accessor methods.
1848</p>
1849
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1850<p>The debugger lets developer inspect Objective C interfaces and their
1851instance variables and class variables. However, the debugger does not know
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1852anything about the properties defined in Objective C interfaces. The debugger
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1853consumes information generated by compiler in DWARF format. The format does
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1854not support encoding of Objective C properties. This proposal describes DWARF
1855extensions to encode Objective C properties, which the debugger can use to let
1856developers inspect Objective C properties.
1857</p>
1858
1859</div>
1860
1861
1862<!-- *********************************************************************** -->
1863<h4>
1864 <a name="objcpropertyproposal">Proposal</a>
1865</h4>
1866<!-- *********************************************************************** -->
1867
1868<div>
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1869<p>Objective C properties exist separately from class members. A property
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1870can be defined only by &quot;setter&quot; and &quot;getter&quot; selectors, and
1871be calculated anew on each access. Or a property can just be a direct access
1872to some declared ivar. Finally it can have an ivar &quot;automatically
1873synthesized&quot; for it by the compiler, in which case the property can be
1874referred to in user code directly using the standard C dereference syntax as
1875well as through the property &quot;dot&quot; syntax, but there is no entry in
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1876the @interface declaration corresponding to this ivar.
1877</p>
1878<p>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1879To facilitate debugging, these properties we will add a new DWARF TAG into the
1880DW_TAG_structure_type definition for the class to hold the description of a
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1881given property, and a set of DWARF attributes that provide said description.
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1882The property tag will also contain the name and declared type of the property.
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1883</p>
1884<p>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1885If there is a related ivar, there will also be a DWARF property attribute placed
1886in the DW_TAG_member DIE for that ivar referring back to the property TAG for
1887that property. And in the case where the compiler synthesizes the ivar directly,
1888the compiler is expected to generate a DW_TAG_member for that ivar (with the
1889DW_AT_artificial set to 1), whose name will be the name used to access this
1890ivar directly in code, and with the property attribute pointing back to the
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1891property it is backing.
1892</p>
1893<p>
1894The following examples will serve as illustration for our discussion:
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1895</p>
1896
1897<div class="doc_code">
1898<pre>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1899@interface I1 {
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1900 int n2;
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1901}
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1902
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1903@property int p1;
1904@property int p2;
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1905@end
1906
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1907@implementation I1
1908@synthesize p1;
1909@synthesize p2 = n2;
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1910@end
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1911</pre>
1912</div>
1913
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1914<p>
1915This produces the following DWARF (this is a &quot;pseudo dwarfdump&quot; output):
1916</p>
1917<div class="doc_code">
1918<pre>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]19190x00000100: TAG_structure_type [7] *
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1920 AT_APPLE_runtime_class( 0x10 )
1921 AT_name( "I1" )
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1922 AT_decl_file( "Objc_Property.m" )
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1923 AT_decl_line( 3 )
1924
19250x00000110 TAG_APPLE_property
1926 AT_name ( "p1" )
1927 AT_type ( {0x00000150} ( int ) )
1928
19290x00000120: TAG_APPLE_property
1930 AT_name ( "p2" )
1931 AT_type ( {0x00000150} ( int ) )
1932
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]19330x00000130: TAG_member [8]
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1934 AT_name( "_p1" )
1935 AT_APPLE_property ( {0x00000110} "p1" )
1936 AT_type( {0x00000150} ( int ) )
1937 AT_artificial ( 0x1 )
1938
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]19390x00000140: TAG_member [8]
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1940 AT_name( "n2" )
1941 AT_APPLE_property ( {0x00000120} "p2" )
1942 AT_type( {0x00000150} ( int ) )
1943
19440x00000150: AT_type( ( int ) )
1945</pre>
1946</div>
1947
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1948<p> Note, the current convention is that the name of the ivar for an
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1949auto-synthesized property is the name of the property from which it derives with
1950an underscore prepended, as is shown in the example.
1951But we actually don't need to know this convention, since we are given the name
1952of the ivar directly.
1953</p>
1954
1955<p>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1956Also, it is common practice in ObjC to have different property declarations in
1957the @interface and @implementation - e.g. to provide a read-only property in
1958the interface,and a read-write interface in the implementation. In that case,
1959the compiler should emit whichever property declaration will be in force in the
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1960current translation unit.
1961</p>
1962
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1963<p> Developers can decorate a property with attributes which are encoded using
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1964DW_AT_APPLE_property_attribute.
1965</p>
1966
1967<div class="doc_code">
1968<pre>
1969@property (readonly, nonatomic) int pr;
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1970</pre>
1971</div>
1972<p>
1973Which produces a property tag:
1974<p>
1975<div class="doc_code">
1976<pre>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1977TAG_APPLE_property [8]
1978 AT_name( "pr" )
1979 AT_type ( {0x00000147} (int) )
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1980 AT_APPLE_property_attribute (DW_APPLE_PROPERTY_readonly, DW_APPLE_PROPERTY_nonatomic)
1981</pre>
1982</div>
1983
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1984<p> The setter and getter method names are attached to the property using
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1985DW_AT_APPLE_property_setter and DW_AT_APPLE_property_getter attributes.
1986</p>
1987<div class="doc_code">
1988<pre>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1989@interface I1
1990@property (setter=myOwnP3Setter:) int p3;
1991-(void)myOwnP3Setter:(int)a;
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1992@end
1993
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1994@implementation I1
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1995@synthesize p3;
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]1996-(void)myOwnP3Setter:(int)a{ }
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1997@end
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]1998</pre>
1999</div>
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]2000
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]2001<p>
2002The DWARF for this would be:
2003</p>
2004<div class="doc_code">
2005<pre>
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]20060x000003bd: TAG_structure_type [7] *
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]2007 AT_APPLE_runtime_class( 0x10 )
2008 AT_name( "I1" )
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]2009 AT_decl_file( "Objc_Property.m" )
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]2010 AT_decl_line( 3 )
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]2011
20120x000003cd TAG_APPLE_property
2013 AT_name ( "p3" )
2014 AT_APPLE_property_setter ( "myOwnP3Setter:" )
2015 AT_type( {0x00000147} ( int ) )
Eric Christopherfc7243a2012-03-06 02:25:36 +0000[diff] [blame]2016
20170x000003f3: TAG_member [8]
2018 AT_name( "_p3" )
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]2019 AT_type ( {0x00000147} ( int ) )
2020 AT_APPLE_property ( {0x000003cd} )
2021 AT_artificial ( 0x1 )
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]2022</pre>
2023</div>
2024
2025</div>
2026
2027<!-- *********************************************************************** -->
2028<h4>
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]2029 <a name="objcpropertynewtags">New DWARF Tags</a>
2030</h4>
2031<!-- *********************************************************************** -->
2032
2033<div>
2034<table border="1" cellspacing="0">
2035 <tr>
2036 <th width=200 >TAG</th>
2037 <th width=200 >Value</th>
2038 </tr>
2039 <tr>
2040 <td width=200 >DW_TAG_APPLE_property</td>
2041 <td width=200 >0x4200</td>
2042 </tr>
2043</table>
2044
2045</div>
2046
2047<!-- *********************************************************************** -->
2048<h4>
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]2049 <a name="objcpropertynewattributes">New DWARF Attributes</a>
2050</h4>
2051<!-- *********************************************************************** -->
2052
2053<div>
2054<table border="1" cellspacing="0">
2055 <tr>
2056 <th width=200 >Attribute</th>
2057 <th width=200 >Value</th>
2058 <th width=200 >Classes</th>
2059 </tr>
2060 <tr>
Devang Patelba98b6b2012-02-06 18:18:25 +0000[diff] [blame]2061 <td width=200 >DW_AT_APPLE_property</td>
2062 <td width=200 >0x3fed</td>
2063 <td width=200 >Reference</td>
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]2064 </tr>
2065 <tr>
2066 <td width=200 >DW_AT_APPLE_property_getter</td>
2067 <td width=200 >0x3fe9</td>
2068 <td width=200 >String</td>
2069 </tr>
2070 <tr>
2071 <td width=200 >DW_AT_APPLE_property_setter</td>
2072 <td width=200 >0x3fea</td>
2073 <td width=200 >String</td>
2074 </tr>
2075 <tr>
2076 <td width=200 >DW_AT_APPLE_property_attribute</td>
2077 <td width=200 >0x3feb</td>
2078 <td width=200 >Constant</td>
2079 </tr>
2080</table>
2081
2082</div>
2083
2084<!-- *********************************************************************** -->
2085<h4>
2086 <a name="objcpropertynewconstants">New DWARF Constants</a>
2087</h4>
2088<!-- *********************************************************************** -->
2089
2090<div>
2091<table border="1" cellspacing="0">
2092 <tr>
2093 <th width=200 >Name</th>
2094 <th width=200 >Value</th>
2095 </tr>
2096 <tr>
2097 <td width=200 >DW_AT_APPLE_PROPERTY_readonly</td>
2098 <td width=200 >0x1</td>
2099 </tr>
2100 <tr>
2101 <td width=200 >DW_AT_APPLE_PROPERTY_readwrite</td>
2102 <td width=200 >0x2</td>
2103 </tr>
2104 <tr>
2105 <td width=200 >DW_AT_APPLE_PROPERTY_assign</td>
2106 <td width=200 >0x4</td>
2107 </tr>
2108 <tr>
2109 <td width=200 >DW_AT_APPLE_PROPERTY_retain</td>
2110 <td width=200 >0x8</td>
2111 </tr>
2112 <tr>
2113 <td width=200 >DW_AT_APPLE_PROPERTY_copy</td>
2114 <td width=200 >0x10</td>
2115 </tr>
2116 <tr>
2117 <td width=200 >DW_AT_APPLE_PROPERTY_nonatomic</td>
2118 <td width=200 >0x20</td>
2119 </tr>
2120</table>
2121
2122</div>
2123</div>
2124</div>
2125
Eric Christopher25e63292012-03-06 02:25:38 +0000[diff] [blame^]2126<div>
2127<!-- ======================================================================= -->
2128<h3>
2129 <a name="acceltable">Name Accelerator Tables</a>
2130</h3>
2131<!-- ======================================================================= -->
2132<!-- ======================================================================= -->
2133<h4>
2134 <a name="acceltableintro">Introduction</a>
2135</h4>
2136<!-- ======================================================================= -->
2137<div>
2138<p>The .debug_pubnames and .debug_pubtypes formats are not what a debugger
2139 needs. The "pub" in the section name indicates that the entries in the
2140 table are publicly visible names only. This means no static or hidden
2141 functions show up in the .debug_pubnames. No static variables or private class
2142 variables are in the .debug_pubtypes. Many compilers add different things to
2143 these tables, so we can't rely upon the contents between gcc, icc, or clang.
2144
2145<p>The typical query given by users tends not to match up with the contents of
2146 these tables. For example, the DWARF spec states that "In the case of the
2147 name of a function member or static data member of a C++ structure, class or
2148 union, the name presented in the .debug_pubnames section is not the simple
2149 name given by the DW_AT_name attribute of the referenced debugging information
2150 entry, but rather the fully qualified name of the data or function member."
2151 So the only names in these tables for complex C++ entries is a fully
2152 qualified name. Debugger users tend not to enter their search strings as
2153 "a::b::c(int,const Foo&) const", but rather as "c", "b::c" , or "a::b::c". So
2154 the name entered in the name table must be demangled in order to chop it up
2155 appropriately and additional names must be manually entered into the table
2156 to make it effective as a name lookup table for debuggers to use.
2157
2158<p>All debuggers currently ignore the .debug_pubnames table as a result of
2159 its inconsistent and useless public-only name content making it a waste of
2160 space in the object file. These tables, when they are written to disk, are
2161 not sorted in any way, leaving every debugger to do its own parsing
2162 and sorting. These tables also include an inlined copy of the string values
2163 in the table itself making the tables much larger than they need to be on
2164 disk, especially for large C++ programs.
2165
2166<p>Can't we just fix the sections by adding all of the names we need to this
2167 table? No, because that is not what the tables are defined to contain and we
2168 won't know the difference between the old bad tables and the new good tables.
2169 At best we could make our own renamed sections that contain all of the data
2170 we need.
2171
2172<p>These tables are also insufficient for what a debugger like LLDB needs.
2173 LLDB uses clang for its expression parsing where LLDB acts as a PCH. LLDB is
2174 then often asked to look for type "foo" or namespace "bar", or list items in
2175 namespace "baz". Namespaces are not included in the pubnames or pubtypes
2176 tables. Since clang asks a lot of questions when it is parsing an expression,
2177 we need to be very fast when looking up names, as it happens a lot. Having new
2178 accelerator tables that are optimized for very quick lookups will benefit
2179 this type of debugging experience greatly.
2180
2181<p>We would like to generate name lookup tables that can be mapped into
2182 memory from disk, and used as is, with little or no up-front parsing. We would
2183 also be able to control the exact content of these different tables so they
2184 contain exactly what we need. The Name Accelerator Tables were designed
2185 to fix these issues. In order to solve these issues we need to:
2186<ul>
2187 <li>Have a format that can be mapped into memory from disk and used as is</li>
2188 <li>Lookups should be very fast</li>
2189 <li>Extensible table format so these tables can be made by many producers</li>
2190 <li>Contain all of the names needed for typical lookups out of the box</li>
2191 <li>Strict rules for the contents of tables</li>
2192</ul>
2193<p>Table size is important and the accelerator table format should allow the
2194 reuse of strings from common string tables so the strings for the names are
2195 not duplicated. We also want to make sure the table is ready to be used as-is
2196 by simply mapping the table into memory with minimal header parsing.
2197
2198<p>The name lookups need to be fast and optimized for the kinds of lookups
2199 that debuggers tend to do. Optimally we would like to touch as few parts of
2200 the mapped table as possible when doing a name lookup and be able to quickly
2201 find the name entry we are looking for, or discover there are no matches. In
2202 the case of debuggers we optimized for lookups that fail most of the time.
2203
2204<p>Each table that is defined should have strict rules on exactly what is in
2205 the accelerator tables and documented so clients can rely on the content.
2206</div>
2207<!-- ======================================================================= -->
2208<h4>
2209 <a name="acceltablehashes">Hash Tables</a>
2210</h4>
2211<!-- ======================================================================= -->
2212<div>
2213<h5>Standard Hash Tables</h5>
2214<p>Typical hash tables have a header, buckets, and each bucket points to the
2215bucket contents:
2216<div class="doc_code">
2217<pre>
2218.------------.
2219| HEADER |
2220|------------|
2221| BUCKETS |
2222|------------|
2223| DATA |
2224`------------'
2225</pre>
2226</div>
2227<p>The BUCKETS are an array of offsets to DATA for each hash:
2228<div class="doc_code">
2229<pre>
2230.------------.
2231| 0x00001000 | BUCKETS[0]
2232| 0x00002000 | BUCKETS[1]
2233| 0x00002200 | BUCKETS[2]
2234| 0x000034f0 | BUCKETS[3]
2235| | ...
2236| 0xXXXXXXXX | BUCKETS[n_buckets]
2237'------------'
2238</pre>
2239</div>
2240<p>So for bucket[3] in the example above, we have an offset into the table
2241 0x000034f0 which points to a chain of entries for the bucket. Each bucket
2242 must contain a next pointer, full 32 bit hash value, the string itself,
2243 and the data for the current string value.
2244<div class="doc_code">
2245<pre>
2246 .------------.
22470x000034f0: | 0x00003500 | next pointer
2248 | 0x12345678 | 32 bit hash
2249 | "erase" | string value
2250 | data[n] | HashData for this bucket
2251 |------------|
22520x00003500: | 0x00003550 | next pointer
2253 | 0x29273623 | 32 bit hash
2254 | "dump" | string value
2255 | data[n] | HashData for this bucket
2256 |------------|
22570x00003550: | 0x00000000 | next pointer
2258 | 0x82638293 | 32 bit hash
2259 | "main" | string value
2260 | data[n] | HashData for this bucket
2261 `------------'
2262</pre>
2263</div>
2264<p>The problem with this layout for debuggers is that we need to optimize for
2265 the negative lookup case where the symbol we're searching for is not present.
2266 So if we were to lookup "printf" in the table above, we would make a 32 hash
2267 for "printf", it might match bucket[3]. We would need to go to the offset
2268 0x000034f0 and start looking to see if our 32 bit hash matches. To do so, we
2269 need to read the next pointer, then read the hash, compare it, and skip to
2270 the next bucket. Each time we are skipping many bytes in memory and touching
2271 new cache pages just to do the compare on the full 32 bit hash. All of these
2272 accesses then tell us that we didn't have a match.
2273
2274<h5>Name Hash Tables</h5>
2275
2276<p>To solve the issues mentioned above we have structured the hash tables
2277 a bit differently: a header, buckets, an array of all unique 32 bit hash
2278 values, followed by an array of hash value data offsets, one for each hash
2279 value, then the data for all hash values:
2280<div class="doc_code">
2281<pre>
2282.-------------.
2283| HEADER |
2284|-------------|
2285| BUCKETS |
2286|-------------|
2287| HASHES |
2288|-------------|
2289| OFFSETS |
2290|-------------|
2291| DATA |
2292`-------------'
2293</pre>
2294</div>
2295<p>The BUCKETS in the Apple tables is an index into the HASHES array. By
2296 making all of the full 32 bit hash values contiguous in memory, we allow
2297 ourselves to efficiently check for a match while touching as little
2298 memory as possible. Most often, checking the 32 bit hash values is as far as
2299 the lookup goes. If it does match, it usually is a match with no collisions.
2300 So for a table with "n_buckets" buckets, and "n_hashes" unique 32 bit hash
2301 values, we can clarify the contents of the BUCKETS, HASHES and OFFSETS as:
2302<div class="doc_code">
2303<pre>
2304.-------------------------.
2305| HEADER.magic | uint32_t
2306| HEADER.version | uint16_t
2307| HEADER.hash_function | uint16_t
2308| HEADER.bucket_count | uint32_t
2309| HEADER.hashes_count | uint32_t
2310| HEADER.header_data_len | uint32_t
2311| HEADER_DATA | HeaderData
2312|-------------------------|
2313| BUCKETS | uint32_t[n_buckets] // 32 bit hash indexes
2314|-------------------------|
2315| HASHES | uint32_t[n_buckets] // 32 bit hash values
2316|-------------------------|
2317| OFFSETS | uint32_t[n_buckets] // 32 bit offsets to hash value data
2318|-------------------------|
2319| ALL HASH DATA |
2320`-------------------------'
2321</pre>
2322</div>
2323<p>So taking the exact same data from the standard hash example above we end up
2324 with:
2325<div class="doc_code">
2326<pre>
2327 .------------.
2328 | HEADER |
2329 |------------|
2330 | 0 | BUCKETS[0]
2331 | 2 | BUCKETS[1]
2332 | 5 | BUCKETS[2]
2333 | 6 | BUCKETS[3]
2334 | | ...
2335 | ... | BUCKETS[n_buckets]
2336 |------------|
2337 | 0x........ | HASHES[0]
2338 | 0x........ | HASHES[1]
2339 | 0x........ | HASHES[2]
2340 | 0x........ | HASHES[3]
2341 | 0x........ | HASHES[4]
2342 | 0x........ | HASHES[5]
2343 | 0x12345678 | HASHES[6] hash for BUCKETS[3]
2344 | 0x29273623 | HASHES[7] hash for BUCKETS[3]
2345 | 0x82638293 | HASHES[8] hash for BUCKETS[3]
2346 | 0x........ | HASHES[9]
2347 | 0x........ | HASHES[10]
2348 | 0x........ | HASHES[11]
2349 | 0x........ | HASHES[12]
2350 | 0x........ | HASHES[13]
2351 | 0x........ | HASHES[n_hashes]
2352 |------------|
2353 | 0x........ | OFFSETS[0]
2354 | 0x........ | OFFSETS[1]
2355 | 0x........ | OFFSETS[2]
2356 | 0x........ | OFFSETS[3]
2357 | 0x........ | OFFSETS[4]
2358 | 0x........ | OFFSETS[5]
2359 | 0x000034f0 | OFFSETS[6] offset for BUCKETS[3]
2360 | 0x00003500 | OFFSETS[7] offset for BUCKETS[3]
2361 | 0x00003550 | OFFSETS[8] offset for BUCKETS[3]
2362 | 0x........ | OFFSETS[9]
2363 | 0x........ | OFFSETS[10]
2364 | 0x........ | OFFSETS[11]
2365 | 0x........ | OFFSETS[12]
2366 | 0x........ | OFFSETS[13]
2367 | 0x........ | OFFSETS[n_hashes]
2368 |------------|
2369 | |
2370 | |
2371 | |
2372 | |
2373 | |
2374 |------------|
23750x000034f0: | 0x00001203 | .debug_str ("erase")
2376 | 0x00000004 | A 32 bit array count - number of HashData with name "erase"
2377 | 0x........ | HashData[0]
2378 | 0x........ | HashData[1]
2379 | 0x........ | HashData[2]
2380 | 0x........ | HashData[3]
2381 | 0x00000000 | String offset into .debug_str (terminate data for hash)
2382 |------------|
23830x00003500: | 0x00001203 | String offset into .debug_str ("collision")
2384 | 0x00000002 | A 32 bit array count - number of HashData with name "collision"
2385 | 0x........ | HashData[0]
2386 | 0x........ | HashData[1]
2387 | 0x00001203 | String offset into .debug_str ("dump")
2388 | 0x00000003 | A 32 bit array count - number of HashData with name "dump"
2389 | 0x........ | HashData[0]
2390 | 0x........ | HashData[1]
2391 | 0x........ | HashData[2]
2392 | 0x00000000 | String offset into .debug_str (terminate data for hash)
2393 |------------|
23940x00003550: | 0x00001203 | String offset into .debug_str ("main")
2395 | 0x00000009 | A 32 bit array count - number of HashData with name "main"
2396 | 0x........ | HashData[0]
2397 | 0x........ | HashData[1]
2398 | 0x........ | HashData[2]
2399 | 0x........ | HashData[3]
2400 | 0x........ | HashData[4]
2401 | 0x........ | HashData[5]
2402 | 0x........ | HashData[6]
2403 | 0x........ | HashData[7]
2404 | 0x........ | HashData[8]
2405 | 0x00000000 | String offset into .debug_str (terminate data for hash)
2406 `------------'
2407</pre>
2408</div>
2409<p>So we still have all of the same data, we just organize it more efficiently
2410 for debugger lookup. If we repeat the same "printf" lookup from above, we
2411 would hash "printf" and find it matches BUCKETS[3] by taking the 32 bit hash
2412 value and modulo it by n_buckets. BUCKETS[3] contains "6" which is the index
2413 into the HASHES table. We would then compare any consecutive 32 bit hashes
2414 values in the HASHES array as long as the hashes would be in BUCKETS[3]. We
2415 do this by verifying that each subsequent hash value modulo n_buckets is still
2416 3. In the case of a failed lookup we would access the memory for BUCKETS[3], and
2417 then compare a few consecutive 32 bit hashes before we know that we have no match.
2418 We don't end up marching through multiple words of memory and we really keep the
2419 number of processor data cache lines being accessed as small as possible.
2420
2421<p>The string hash that is used for these lookup tables is the Daniel J.
2422 Bernstein hash which is also used in the ELF GNU_HASH sections. It is a very
2423 good hash for all kinds of names in programs with very few hash collisions.
2424
2425<p>Empty buckets are designated by using an invalid hash index of UINT32_MAX.
2426</div>
2427<!-- ======================================================================= -->
2428<h4>
2429 <a name="acceltabledetails">Details</a>
2430</h4>
2431<!-- ======================================================================= -->
2432<div>
2433<p>These name hash tables are designed to be generic where specializations of
2434 the table get to define additional data that goes into the header
2435 ("HeaderData"), how the string value is stored ("KeyType") and the content
2436 of the data for each hash value.
2437
2438<h5>Header Layout</h5>
2439<p>The header has a fixed part, and the specialized part. The exact format of
2440 the header is:
2441<div class="doc_code">
2442<pre>
2443struct Header
2444{
2445 uint32_t magic; // 'HASH' magic value to allow endian detection
2446 uint16_t version; // Version number
2447 uint16_t hash_function; // The hash function enumeration that was used
2448 uint32_t bucket_count; // The number of buckets in this hash table
2449 uint32_t hashes_count; // The total number of unique hash values and hash data offsets in this table
2450 uint32_t header_data_len; // The bytes to skip to get to the hash indexes (buckets) for correct alignment
2451 // Specifically the length of the following HeaderData field - this does not
2452 // include the size of the preceding fields
2453 HeaderData header_data; // Implementation specific header data
2454};
2455</pre>
2456</div>
2457<p>The header starts with a 32 bit "magic" value which must be 'HASH' encoded as
2458 an ASCII integer. This allows the detection of the start of the hash table and
2459 also allows the table's byte order to be determined so the table can be
2460 correctly extracted. The "magic" value is followed by a 16 bit version number
2461 which allows the table to be revised and modified in the future. The current
2462 version number is 1. "hash_function" is a uint16_t enumeration that specifies
2463 which hash function was used to produce this table. The current values for the
2464 hash function enumerations include:
2465<div class="doc_code">
2466<pre>
2467enum HashFunctionType
2468{
2469 eHashFunctionDJB = 0u, // Daniel J Bernstein hash function
2470};
2471</pre>
2472</div>
2473<p>"bucket_count" is a 32 bit unsigned integer that represents how many buckets
2474 are in the BUCKETS array. "hashes_count" is the number of unique 32 bit hash
2475 values that are in the HASHES array, and is the same number of offsets are
2476 contained in the OFFSETS array. "header_data_len" specifies the size in
2477 bytes of the HeaderData that is filled in by specialized versions of this
2478 table.
2479
2480<h5>Fixed Lookup</h5>
2481<p>The header is followed by the buckets, hashes, offsets, and hash value
2482 data.
2483<div class="doc_code">
2484<pre>
2485struct FixedTable
2486{
2487 uint32_t buckets[Header.bucket_count]; // An array of hash indexes into the "hashes[]" array below
2488 uint32_t hashes [Header.hashes_count]; // Every unique 32 bit hash for the entire table is in this table
2489 uint32_t offsets[Header.hashes_count]; // An offset that corresponds to each item in the "hashes[]" array above
2490};
2491</pre>
2492</div>
2493<p>"buckets" is an array of 32 bit indexes into the "hashes" array. The
2494 "hashes" array contains all of the 32 bit hash values for all names in the
2495 hash table. Each hash in the "hashes" table has an offset in the "offsets"
2496 array that points to the data for the hash value.
2497
2498<p>This table setup makes it very easy to repurpose these tables to contain
2499 different data, while keeping the lookup mechanism the same for all tables.
2500 This layout also makes it possible to save the table to disk and map it in
2501 later and do very efficient name lookups with little or no parsing.
2502
2503<p>DWARF lookup tables can be implemented in a variety of ways and can store
2504 a lot of information for each name. We want to make the DWARF tables
2505 extensible and able to store the data efficiently so we have used some of the
2506 DWARF features that enable efficient data storage to define exactly what kind
2507 of data we store for each name.
2508
2509<p>The "HeaderData" contains a definition of the contents of each HashData
2510 chunk. We might want to store an offset to all of the debug information
2511 entries (DIEs) for each name. To keep things extensible, we create a list of
2512 items, or Atoms, that are contained in the data for each name. First comes the
2513 type of the data in each atom:
2514<div class="doc_code">
2515<pre>
2516enum AtomType
2517{
2518 eAtomTypeNULL = 0u,
2519 eAtomTypeDIEOffset = 1u, // DIE offset, check form for encoding
2520 eAtomTypeCUOffset = 2u, // DIE offset of the compiler unit header that contains the item in question
2521 eAtomTypeTag = 3u, // DW_TAG_xxx value, should be encoded as DW_FORM_data1 (if no tags exceed 255) or DW_FORM_data2
2522 eAtomTypeNameFlags = 4u, // Flags from enum NameFlags
2523 eAtomTypeTypeFlags = 5u, // Flags from enum TypeFlags
2524};
2525</pre>
2526</div>
2527<p>The enumeration values and their meanings are:
2528<div class="doc_code">
2529<pre>
2530 eAtomTypeNULL - a termination atom that specifies the end of the atom list
2531 eAtomTypeDIEOffset - an offset into the .debug_info section for the DWARF DIE for this name
2532 eAtomTypeCUOffset - an offset into the .debug_info section for the CU that contains the DIE
2533 eAtomTypeDIETag - The DW_TAG_XXX enumeration value so you don't have to parse the DWARF to see what it is
2534 eAtomTypeNameFlags - Flags for functions and global variables (isFunction, isInlined, isExternal...)
2535 eAtomTypeTypeFlags - Flags for types (isCXXClass, isObjCClass, ...)
2536</pre>
2537</div>
2538<p>Then we allow each atom type to define the atom type and how the data for
2539 each atom type data is encoded:
2540<div class="doc_code">
2541<pre>
2542struct Atom
2543{
2544 uint16_t type; // AtomType enum value
2545 uint16_t form; // DWARF DW_FORM_XXX defines
2546};
2547</pre>
2548</div>
2549<p>The "form" type above is from the DWARF specification and defines the
2550 exact encoding of the data for the Atom type. See the DWARF specification for
2551 the DW_FORM_ definitions.
2552<div class="doc_code">
2553<pre>
2554struct HeaderData
2555{
2556 uint32_t die_offset_base;
2557 uint32_t atom_count;
2558 Atoms atoms[atom_count0];
2559};
2560</pre>
2561</div>
2562<p>"HeaderData" defines the base DIE offset that should be added to any atoms
2563 that are encoded using the DW_FORM_ref1, DW_FORM_ref2, DW_FORM_ref4,
2564 DW_FORM_ref8 or DW_FORM_ref_udata. It also defines what is contained in
2565 each "HashData" object -- Atom.form tells us how large each field will be in
2566 the HashData and the Atom.type tells us how this data should be interpreted.
2567
2568<p>For the current implementations of the ".apple_names" (all functions + globals),
2569 the ".apple_types" (names of all types that are defined), and the
2570 ".apple_namespaces" (all namespaces), we currently set the Atom array to be:
2571<div class="doc_code">
2572<pre>
2573HeaderData.atom_count = 1;
2574HeaderData.atoms[0].type = eAtomTypeDIEOffset;
2575HeaderData.atoms[0].form = DW_FORM_data4;
2576</pre>
2577</div>
2578<p>This defines the contents to be the DIE offset (eAtomTypeDIEOffset) that is
2579 encoded as a 32 bit value (DW_FORM_data4). This allows a single name to have
2580 multiple matching DIEs in a single file, which could come up with an inlined
2581 function for instance. Future tables could include more information about the
2582 DIE such as flags indicating if the DIE is a function, method, block,
2583 or inlined.
2584
2585<p>The KeyType for the DWARF table is a 32 bit string table offset into the
2586 ".debug_str" table. The ".debug_str" is the string table for the DWARF which
2587 may already contain copies of all of the strings. This helps make sure, with
2588 help from the compiler, that we reuse the strings between all of the DWARF
2589 sections and keeps the hash table size down. Another benefit to having the
2590 compiler generate all strings as DW_FORM_strp in the debug info, is that
2591 DWARF parsing can be made much faster.
2592
2593<p>After a lookup is made, we get an offset into the hash data. The hash data
2594 needs to be able to deal with 32 bit hash collisions, so the chunk of data
2595 at the offset in the hash data consists of a triple:
2596<div class="doc_code">
2597<pre>
2598uint32_t str_offset
2599uint32_t hash_data_count
2600HashData[hash_data_count]
2601</pre>
2602</div>
2603<p>If "str_offset" is zero, then the bucket contents are done. 99.9% of the
2604 hash data chunks contain a single item (no 32 bit hash collision):
2605<div class="doc_code">
2606<pre>
2607.------------.
2608| 0x00001023 | uint32_t KeyType (.debug_str[0x0001023] => "main")
2609| 0x00000004 | uint32_t HashData count
2610| 0x........ | uint32_t HashData[0] DIE offset
2611| 0x........ | uint32_t HashData[1] DIE offset
2612| 0x........ | uint32_t HashData[2] DIE offset
2613| 0x........ | uint32_t HashData[3] DIE offset
2614| 0x00000000 | uint32_t KeyType (end of hash chain)
2615`------------'
2616</pre>
2617</div>
2618<p>If there are collisions, you will have multiple valid string offsets:
2619<div class="doc_code">
2620<pre>
2621.------------.
2622| 0x00001023 | uint32_t KeyType (.debug_str[0x0001023] => "main")
2623| 0x00000004 | uint32_t HashData count
2624| 0x........ | uint32_t HashData[0] DIE offset
2625| 0x........ | uint32_t HashData[1] DIE offset
2626| 0x........ | uint32_t HashData[2] DIE offset
2627| 0x........ | uint32_t HashData[3] DIE offset
2628| 0x00002023 | uint32_t KeyType (.debug_str[0x0002023] => "print")
2629| 0x00000002 | uint32_t HashData count
2630| 0x........ | uint32_t HashData[0] DIE offset
2631| 0x........ | uint32_t HashData[1] DIE offset
2632| 0x00000000 | uint32_t KeyType (end of hash chain)
2633`------------'
2634</pre>
2635</div>
2636<p>Current testing with real world C++ binaries has shown that there is around 1
2637 32 bit hash collision per 100,000 name entries.
2638</div>
2639<!-- ======================================================================= -->
2640<h4>
2641 <a name="acceltablecontents">Contents</a>
2642</h4>
2643<!-- ======================================================================= -->
2644<div>
2645<p>As we said, we want to strictly define exactly what is included in the
2646 different tables. For DWARF, we have 3 tables: ".apple_names", ".apple_types",
2647 and ".apple_namespaces".
2648
2649<p>".apple_names" sections should contain an entry for each DWARF DIE whose
2650 DW_TAG is a DW_TAG_label, DW_TAG_inlined_subroutine, or DW_TAG_subprogram that
2651 has address attributes: DW_AT_low_pc, DW_AT_high_pc, DW_AT_ranges or
2652 DW_AT_entry_pc. It also contains DW_TAG_variable DIEs that have a DW_OP_addr
2653 in the location (global and static variables). All global and static variables
2654 should be included, including those scoped withing functions and classes. For
2655 example using the following code:
2656<div class="doc_code">
2657<pre>
2658static int var = 0;
2659
2660void f ()
2661{
2662 static int var = 0;
2663}
2664</pre>
2665</div>
2666<p>Both of the static "var" variables would be included in the table. All
2667 functions should emit both their full names and their basenames. For C or C++,
2668 the full name is the mangled name (if available) which is usually in the
2669 DW_AT_MIPS_linkage_name attribute, and the DW_AT_name contains the function
2670 basename. If global or static variables have a mangled name in a
2671 DW_AT_MIPS_linkage_name attribute, this should be emitted along with the
2672 simple name found in the DW_AT_name attribute.
2673
2674<p>".apple_types" sections should contain an entry for each DWARF DIE whose
2675 tag is one of:
2676<ul>
2677 <li>DW_TAG_array_type</li>
2678 <li>DW_TAG_class_type</li>
2679 <li>DW_TAG_enumeration_type</li>
2680 <li>DW_TAG_pointer_type</li>
2681 <li>DW_TAG_reference_type</li>
2682 <li>DW_TAG_string_type</li>
2683 <li>DW_TAG_structure_type</li>
2684 <li>DW_TAG_subroutine_type</li>
2685 <li>DW_TAG_typedef</li>
2686 <li>DW_TAG_union_type</li>
2687 <li>DW_TAG_ptr_to_member_type</li>
2688 <li>DW_TAG_set_type</li>
2689 <li>DW_TAG_subrange_type</li>
2690 <li>DW_TAG_base_type</li>
2691 <li>DW_TAG_const_type</li>
2692 <li>DW_TAG_constant</li>
2693 <li>DW_TAG_file_type</li>
2694 <li>DW_TAG_namelist</li>
2695 <li>DW_TAG_packed_type</li>
2696 <li>DW_TAG_volatile_type</li>
2697 <li>DW_TAG_restrict_type</li>
2698 <li>DW_TAG_interface_type</li>
2699 <li>DW_TAG_unspecified_type</li>
2700 <li>DW_TAG_shared_type</li>
2701</ul>
2702<p>Only entries with a DW_AT_name attribute are included, and the entry must
2703 not be a forward declaration (DW_AT_declaration attribute with a non-zero value).
2704 For example, using the following code:
2705<div class="doc_code">
2706<pre>
2707int main ()
2708{
2709 int *b = 0;
2710 return *b;
2711}
2712</pre>
2713</div>
2714<p>We get a few type DIEs:
2715<div class="doc_code">
2716<pre>
27170x00000067: TAG_base_type [5]
2718 AT_encoding( DW_ATE_signed )
2719 AT_name( "int" )
2720 AT_byte_size( 0x04 )
2721
27220x0000006e: TAG_pointer_type [6]
2723 AT_type( {0x00000067} ( int ) )
2724 AT_byte_size( 0x08 )
2725</pre>
2726</div>
2727<p>The DW_TAG_pointer_type is not included because it does not have a DW_AT_name.
2728
2729<p>".apple_namespaces" section should contain all DW_TAG_namespace DIEs. If
2730 we run into a namespace that has no name this is an anonymous namespace,
2731 and the name should be output as "(anonymous namespace)" (without the quotes).
2732 Why? This matches the output of the abi::cxa_demangle() that is in the standard
2733 C++ library that demangles mangled names.
2734</div>
2735
2736<!-- ======================================================================= -->
2737<h4>
2738 <a name="acceltableextensions">Language Extensions and File Format Changes</a>
2739</h4>
2740<!-- ======================================================================= -->
2741<div>
2742<h5>Objective-C Extensions</h5>
2743<p>".apple_objc" section should contain all DW_TAG_subprogram DIEs for an
2744 Objective-C class. The name used in the hash table is the name of the
2745 Objective-C class itself. If the Objective-C class has a category, then an
2746 entry is made for both the class name without the category, and for the class
2747 name with the category. So if we have a DIE at offset 0x1234 with a name
2748 of method "-[NSString(my_additions) stringWithSpecialString:]", we would add
2749 an entry for "NSString" that points to DIE 0x1234, and an entry for
2750 "NSString(my_additions)" that points to 0x1234. This allows us to quickly
2751 track down all Objective-C methods for an Objective-C class when doing
2752 expressions. It is needed because of the dynamic nature of Objective-C where
2753 anyone can add methods to a class. The DWARF for Objective-C methods is also
2754 emitted differently from C++ classes where the methods are not usually
2755 contained in the class definition, they are scattered about across one or more
2756 compile units. Categories can also be defined in different shared libraries.
2757 So we need to be able to quickly find all of the methods and class functions
2758 given the Objective-C class name, or quickly find all methods and class
2759 functions for a class + category name. This table does not contain any selector
2760 names, it just maps Objective-C class names (or class names + category) to all
2761 of the methods and class functions. The selectors are added as function
2762 basenames in the .debug_names section.
2763
2764<p>In the ".apple_names" section for Objective-C functions, the full name is the
2765 entire function name with the brackets ("-[NSString stringWithCString:]") and the
2766 basename is the selector only ("stringWithCString:").
2767
2768<h5>Mach-O Changes</h5>
2769<p>The sections names for the apple hash tables are for non mach-o files. For
2770 mach-o files, the sections should be contained in the "__DWARF" segment with
2771 names as follows:
2772<ul>
2773 <li>".apple_names" -> "__apple_names"</li>
2774 <li>".apple_types" -> "__apple_types"</li>
2775 <li>".apple_namespaces" -> "__apple_namespac" (16 character limit)</li>
2776 <li> ".apple_objc" -> "__apple_objc"</li>
2777</ul>
2778</div>
2779</div>
2780
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]2781<!-- *********************************************************************** -->
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]2782
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]2783<hr>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]2784<address>
2785 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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2790 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]2791 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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2795</body>
2796</html>