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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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9<body>
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>
58 <li><a href="#objcproperty">Debugging Information Extension
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>
66
67 </ol>
68 </li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]69</ul>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]70</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]71<td class="right">
Misha Brukmane849a1a2004-05-12 21:26:16 +0000[diff] [blame]72<img src="img/venusflytrap.jpg" alt="A leafy and green bug eater" width="247"
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]73height="369">
74</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]75</tr></table>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]76
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]77<div class="doc_author">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]78 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
Jim Laskeyc760a922007-03-14 19:32:21 +0000[diff] [blame]79 and <a href="mailto:jlaskey@mac.com">Jim Laskey</a></p>
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]80</div>
81
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]82
83<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]84<h2><a name="introduction">Introduction</a></h2>
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]85<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]86
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]87<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]88
89<p>This document is the central repository for all information pertaining to
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]90 debug information in LLVM. It describes the <a href="#format">actual format
91 that the LLVM debug information</a> takes, which is useful for those
92 interested in creating front-ends or dealing directly with the information.
Chris Lattner8ad2f982009-07-18 21:47:15 +0000[diff] [blame]93 Further, this document provides specific examples of what debug information
Chris Lattner89940752011-01-18 06:12:10 +0000[diff] [blame]94 for C/C++ looks like.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]95
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]96<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]97<h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]98 <a name="phil">Philosophy behind LLVM debugging information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]99</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]100
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]101<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]102
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]103<p>The idea of the LLVM debugging information is to capture how the important
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]104 pieces of the source-language's Abstract Syntax Tree map onto LLVM code.
105 Several design aspects have shaped the solution that appears here. The
106 important ones are:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]107
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]108<ul>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]109 <li>Debugging information should have very little impact on the rest of the
110 compiler. No transformations, analyses, or code generators should need to
111 be modified because of debugging information.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]112
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]113 <li>LLVM optimizations should interact in <a href="#debugopt">well-defined and
114 easily described ways</a> with the debugging information.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]115
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]116 <li>Because LLVM is designed to support arbitrary programming languages,
117 LLVM-to-LLVM tools should not need to know anything about the semantics of
118 the source-level-language.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]119
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]120 <li>Source-level languages are often <b>widely</b> different from one another.
121 LLVM should not put any restrictions of the flavor of the source-language,
122 and the debugging information should work with any language.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]123
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]124 <li>With code generator support, it should be possible to use an LLVM compiler
125 to compile a program to native machine code and standard debugging
126 formats. This allows compatibility with traditional machine-code level
127 debuggers, like GDB or DBX.</li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]128</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]129
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]130<p>The approach used by the LLVM implementation is to use a small set
131 of <a href="#format_common_intrinsics">intrinsic functions</a> to define a
132 mapping between LLVM program objects and the source-level objects. The
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]133 description of the source-level program is maintained in LLVM metadata
134 in an <a href="#ccxx_frontend">implementation-defined format</a>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]135 (the C/C++ front-end currently uses working draft 7 of
136 the <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3
137 standard</a>).</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]138
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]139<p>When a program is being debugged, a debugger interacts with the user and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]140 turns the stored debug information into source-language specific information.
141 As such, a debugger must be aware of the source-language, and is thus tied to
142 a specific language or family of languages.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]143
144</div>
145
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]146<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]147<h3>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]148 <a name="consumers">Debug information consumers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]149</h3>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]150
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]151<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]152
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]153<p>The role of debug information is to provide meta information normally
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]154 stripped away during the compilation process. This meta information provides
155 an LLVM user a relationship between generated code and the original program
156 source code.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]157
Chris Lattnerc3107782010-04-05 04:11:11 +0000[diff] [blame]158<p>Currently, debug information is consumed by DwarfDebug to produce dwarf
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]159 information used by the gdb debugger. Other targets could use the same
160 information to produce stabs or other debug forms.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]161
162<p>It would also be reasonable to use debug information to feed profiling tools
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]163 for analysis of generated code, or, tools for reconstructing the original
164 source from generated code.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]165
166<p>TODO - expound a bit more.</p>
167
168</div>
169
170<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]171<h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]172 <a name="debugopt">Debugging optimized code</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]173</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]174
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]175<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]176
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]177<p>An extremely high priority of LLVM debugging information is to make it
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]178 interact well with optimizations and analysis. In particular, the LLVM debug
179 information provides the following guarantees:</p>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]180
181<ul>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]182 <li>LLVM debug information <b>always provides information to accurately read
183 the source-level state of the program</b>, regardless of which LLVM
184 optimizations have been run, and without any modification to the
185 optimizations themselves. However, some optimizations may impact the
186 ability to modify the current state of the program with a debugger, such
187 as setting program variables, or calling functions that have been
188 deleted.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]189
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]190 <li>As desired, LLVM optimizations can be upgraded to be aware of the LLVM
191 debugging information, allowing them to update the debugging information
192 as they perform aggressive optimizations. This means that, with effort,
193 the LLVM optimizers could optimize debug code just as well as non-debug
194 code.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]195
Devang Patele0bdc592011-05-31 17:45:27 +0000[diff] [blame]196 <li>LLVM debug information does not prevent optimizations from
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]197 happening (for example inlining, basic block reordering/merging/cleanup,
Devang Patelf729e912011-05-31 18:06:14 +0000[diff] [blame]198 tail duplication, etc).</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]199
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]200 <li>LLVM debug information is automatically optimized along with the rest of
201 the program, using existing facilities. For example, duplicate
202 information is automatically merged by the linker, and unused information
203 is automatically removed.</li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]204</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]205
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]206<p>Basically, the debug information allows you to compile a program with
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]207 "<tt>-O0 -g</tt>" and get full debug information, allowing you to arbitrarily
208 modify the program as it executes from a debugger. Compiling a program with
209 "<tt>-O3 -g</tt>" gives you full debug information that is always available
210 and accurate for reading (e.g., you get accurate stack traces despite tail
211 call elimination and inlining), but you might lose the ability to modify the
212 program and call functions where were optimized out of the program, or
213 inlined away completely.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]214
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]215<p><a href="TestingGuide.html#quicktestsuite">LLVM test suite</a> provides a
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]216 framework to test optimizer's handling of debugging information. It can be
217 run like this:</p>
Devang Patela5c05aa2008-11-21 19:35:57 +0000[diff] [blame]218
219<div class="doc_code">
220<pre>
221% cd llvm/projects/test-suite/MultiSource/Benchmarks # or some other level
222% make TEST=dbgopt
223</pre>
224</div>
225
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]226<p>This will test impact of debugging information on optimization passes. If
227 debugging information influences optimization passes then it will be reported
228 as a failure. See <a href="TestingGuide.html">TestingGuide</a> for more
229 information on LLVM test infrastructure and how to run various tests.</p>
Devang Patela5c05aa2008-11-21 19:35:57 +0000[diff] [blame]230
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]231</div>
232
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]233</div>
234
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]235<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]236<h2>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]237 <a name="format">Debugging information format</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]238</h2>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]239<!-- *********************************************************************** -->
240
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]241<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]242
243<p>LLVM debugging information has been carefully designed to make it possible
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]244 for the optimizer to optimize the program and debugging information without
245 necessarily having to know anything about debugging information. In
John Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]246 particular, the use of metadata avoids duplicated debugging information from
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]247 the beginning, and the global dead code elimination pass automatically
248 deletes debugging information for a function if it decides to delete the
249 function. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]250
251<p>To do this, most of the debugging information (descriptors for types,
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]252 variables, functions, source files, etc) is inserted by the language
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]253 front-end in the form of LLVM metadata. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]254
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]255<p>Debug information is designed to be agnostic about the target debugger and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]256 debugging information representation (e.g. DWARF/Stabs/etc). It uses a
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]257 generic pass to decode the information that represents variables, types,
258 functions, namespaces, etc: this allows for arbitrary source-language
259 semantics and type-systems to be used, as long as there is a module
260 written for the target debugger to interpret the information. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]261
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]262<p>To provide basic functionality, the LLVM debugger does have to make some
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]263 assumptions about the source-level language being debugged, though it keeps
264 these to a minimum. The only common features that the LLVM debugger assumes
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]265 exist are <a href="#format_files">source files</a>,
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]266 and <a href="#format_global_variables">program objects</a>. These abstract
267 objects are used by a debugger to form stack traces, show information about
268 local variables, etc.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]269
270<p>This section of the documentation first describes the representation aspects
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]271 common to any source-language. The <a href="#ccxx_frontend">next section</a>
272 describes the data layout conventions used by the C and C++ front-ends.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]273
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]274<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]275<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]276 <a name="debug_info_descriptors">Debug information descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]277</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]278
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]279<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]280
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]281<p>In consideration of the complexity and volume of debug information, LLVM
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]282 provides a specification for well formed debug descriptors. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]283
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]284<p>Consumers of LLVM debug information expect the descriptors for program
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]285 objects to start in a canonical format, but the descriptors can include
286 additional information appended at the end that is source-language
287 specific. All LLVM debugging information is versioned, allowing backwards
288 compatibility in the case that the core structures need to change in some
289 way. Also, all debugging information objects start with a tag to indicate
290 what type of object it is. The source-language is allowed to define its own
291 objects, by using unreserved tag numbers. We recommend using with tags in
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]292 the range 0x1000 through 0x2000 (there is a defined enum DW_TAG_user_base =
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]293 0x1000.)</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]294
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]295<p>The fields of debug descriptors used internally by LLVM
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]296 are restricted to only the simple data types <tt>i32</tt>, <tt>i1</tt>,
297 <tt>float</tt>, <tt>double</tt>, <tt>mdstring</tt> and <tt>mdnode</tt>. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]298
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]299<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]300<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]301!1 = metadata !{
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]302 i32, ;; A tag
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]303 ...
304}
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]305</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]306</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]307
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]308<p><a name="LLVMDebugVersion">The first field of a descriptor is always an
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]309 <tt>i32</tt> containing a tag value identifying the content of the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]310 descriptor. The remaining fields are specific to the descriptor. The values
311 of tags are loosely bound to the tag values of DWARF information entries.
312 However, that does not restrict the use of the information supplied to DWARF
313 targets. To facilitate versioning of debug information, the tag is augmented
Nick Lewyckyf3379da2011-07-25 21:13:23 +0000[diff] [blame]314 with the current debug version (LLVMDebugVersion = 8 &lt;&lt; 16 or
315 0x80000 or 524288.)</a></p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]316
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]317<p>The details of the various descriptors follow.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]318
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]319<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]320<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]321 <a name="format_compile_units">Compile unit descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]322</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]323
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]324<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]325
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]326<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]327<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]328!0 = metadata !{
329 i32, ;; Tag = 17 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
330 ;; (DW_TAG_compile_unit)
331 i32, ;; Unused field.
332 i32, ;; DWARF language identifier (ex. DW_LANG_C89)
333 metadata, ;; Source file name
334 metadata, ;; Source file directory (includes trailing slash)
335 metadata ;; Producer (ex. "4.0.1 LLVM (LLVM research group)")
336 i1, ;; True if this is a main compile unit.
337 i1, ;; True if this is optimized.
338 metadata, ;; Flags
339 i32 ;; Runtime version
Devang Patel9b4a2ac2011-09-09 17:07:15 +0000[diff] [blame]340 metadata ;; List of enums types
341 metadata ;; List of retained types
342 metadata ;; List of subprograms
343 metadata ;; List of global variables
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]344}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]345</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]346</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]347
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]348<p>These descriptors contain a source language ID for the file (we use the DWARF
349 3.0 ID numbers, such as <tt>DW_LANG_C89</tt>, <tt>DW_LANG_C_plus_plus</tt>,
350 <tt>DW_LANG_Cobol74</tt>, etc), three strings describing the filename,
351 working directory of the compiler, and an identifier string for the compiler
352 that produced it.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]353
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]354<p>Compile unit descriptors provide the root context for objects declared in a
Devang Patel464f4ef2011-05-03 16:18:28 +0000[diff] [blame]355 specific compilation unit. File descriptors are defined using this context.
356 These descriptors are collected by a named metadata
Devang Patel9b4a2ac2011-09-09 17:07:15 +0000[diff] [blame]357 <tt>!llvm.dbg.cu</tt>. Compile unit descriptor keeps track of subprograms,
358 global variables and type information.
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]359
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]360</div>
361
362<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]363<h4>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]364 <a name="format_files">File descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]365</h4>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]366
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]367<div>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]368
369<div class="doc_code">
370<pre>
371!0 = metadata !{
372 i32, ;; Tag = 41 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
373 ;; (DW_TAG_file_type)
374 metadata, ;; Source file name
375 metadata, ;; Source file directory (includes trailing slash)
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]376 metadata ;; Unused
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]377}
378</pre>
379</div>
380
John Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]381<p>These descriptors contain information for a file. Global variables and top
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]382 level functions would be defined using this context.k File descriptors also
383 provide context for source line correspondence. </p>
384
385<p>Each input file is encoded as a separate file descriptor in LLVM debugging
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]386 information output. </p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]387
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]388</div>
389
390<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]391<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]392 <a name="format_global_variables">Global variable descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]393</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]394
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]395<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]396
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]397<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]398<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]399!1 = metadata !{
400 i32, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
401 ;; (DW_TAG_variable)
402 i32, ;; Unused field.
403 metadata, ;; Reference to context descriptor
404 metadata, ;; Name
405 metadata, ;; Display name (fully qualified C++ name)
406 metadata, ;; MIPS linkage name (for C++)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]407 metadata, ;; Reference to file where defined
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]408 i32, ;; Line number where defined
409 metadata, ;; Reference to type descriptor
410 i1, ;; True if the global is local to compile unit (static)
411 i1, ;; True if the global is defined in the compile unit (not extern)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]412 {}* ;; Reference to the global variable
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]413}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]414</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]415</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]416
417<p>These descriptors provide debug information about globals variables. The
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]418provide details such as name, type and where the variable is defined. All
419global variables are collected by named metadata <tt>!llvm.dbg.gv</tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]420
421</div>
422
423<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]424<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]425 <a name="format_subprograms">Subprogram descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]426</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]427
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]428<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]429
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]430<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]431<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]432!2 = metadata !{
433 i32, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
434 ;; (DW_TAG_subprogram)
435 i32, ;; Unused field.
436 metadata, ;; Reference to context descriptor
437 metadata, ;; Name
438 metadata, ;; Display name (fully qualified C++ name)
439 metadata, ;; MIPS linkage name (for C++)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]440 metadata, ;; Reference to file where defined
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]441 i32, ;; Line number where defined
442 metadata, ;; Reference to type descriptor
443 i1, ;; True if the global is local to compile unit (static)
Devang Patel5e06bb82011-04-22 23:10:17 +0000[diff] [blame]444 i1, ;; True if the global is defined in the compile unit (not extern)
445 i32, ;; Virtuality, e.g. dwarf::DW_VIRTUALITY__virtual
446 i32, ;; Index into a virtual function
Devang Patel80ecc152010-06-04 22:49:55 +0000[diff] [blame]447 metadata, ;; indicates which base type contains the vtable pointer for the
448 ;; derived class
Devang Patel473f95f2011-12-16 17:50:04 +0000[diff] [blame]449 i32, ;; Flags - Artifical, Private, Protected, Explicit, Prototyped.
Devang Patel5e06bb82011-04-22 23:10:17 +0000[diff] [blame]450 i1, ;; isOptimized
451 Function *,;; Pointer to LLVM function
452 metadata, ;; Lists function template parameters
453 metadata ;; Function declaration descriptor
Devang Patel93d39be2011-08-19 23:28:12 +0000[diff] [blame]454 metadata ;; List of function variables
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]455}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]456</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]457</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]458
459<p>These descriptors provide debug information about functions, methods and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]460 subprograms. They provide details such as name, return types and the source
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]461 location where the subprogram is defined.
462 All subprogram descriptors are collected by a named metadata
463 <tt>!llvm.dbg.sp</tt>.
464</p>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]465
466</div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]467
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]468<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]469<h4>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]470 <a name="format_blocks">Block descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]471</h4>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]472
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]473<div>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]474
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]475<div class="doc_code">
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]476<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]477!3 = metadata !{
Devang Patelc79dda22010-10-04 16:51:59 +0000[diff] [blame]478 i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
Devang Patel7f271fc2010-10-01 22:45:00 +0000[diff] [blame]479 metadata,;; Reference to context descriptor
480 i32, ;; Line number
Devang Patel90d81f12011-03-08 16:25:29 +0000[diff] [blame]481 i32, ;; Column number
482 metadata,;; Reference to source file
483 i32 ;; Unique ID to identify blocks from a template function
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]484}
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]485</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]486</div>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]487
Eric Christopher6618a242011-10-11 22:59:11 +0000[diff] [blame]488<p>This descriptor provides debug information about nested blocks within a
Devang Patel7f271fc2010-10-01 22:45:00 +0000[diff] [blame]489 subprogram. The line number and column numbers are used to dinstinguish
490 two lexical blocks at same depth. </p>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]491
Eric Christopher6618a242011-10-11 22:59:11 +0000[diff] [blame]492<div class="doc_code">
493<pre>
494!3 = metadata !{
495 i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
496 metadata ;; Reference to the scope we're annotating with a file change
497 metadata,;; Reference to the file the scope is enclosed in.
498}
499</pre>
500</div>
501
502<p>This descriptor provides a wrapper around a lexical scope to handle file
503 changes in the middle of a lexical block.</p>
504
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]505</div>
506
507<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]508<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]509 <a name="format_basic_type">Basic type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]510</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]511
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]512<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]513
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]514<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]515<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]516!4 = metadata !{
517 i32, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
518 ;; (DW_TAG_base_type)
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]519 metadata, ;; Reference to context
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]520 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]521 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]522 i32, ;; Line number where defined (may be 0)
523 i64, ;; Size in bits
524 i64, ;; Alignment in bits
525 i64, ;; Offset in bits
526 i32, ;; Flags
527 i32 ;; DWARF type encoding
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]528}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]529</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]530</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]531
532<p>These descriptors define primitive types used in the code. Example int, bool
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]533 and float. The context provides the scope of the type, which is usually the
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]534 top level. Since basic types are not usually user defined the context
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]535 and line number can be left as NULL and 0. The size, alignment and offset
536 are expressed in bits and can be 64 bit values. The alignment is used to
537 round the offset when embedded in a
538 <a href="#format_composite_type">composite type</a> (example to keep float
539 doubles on 64 bit boundaries.) The offset is the bit offset if embedded in
540 a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]541
542<p>The type encoding provides the details of the type. The values are typically
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]543 one of the following:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]544
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]545<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]546<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]547DW_ATE_address = 1
548DW_ATE_boolean = 2
549DW_ATE_float = 4
550DW_ATE_signed = 5
551DW_ATE_signed_char = 6
552DW_ATE_unsigned = 7
553DW_ATE_unsigned_char = 8
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]554</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]555</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]556
557</div>
558
559<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]560<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]561 <a name="format_derived_type">Derived type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]562</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]563
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]564<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]565
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]566<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]567<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]568!5 = metadata !{
569 i32, ;; Tag (see below)
570 metadata, ;; Reference to context
571 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]572 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]573 i32, ;; Line number where defined (may be 0)
Devang Patel0ffd10b2010-10-01 19:19:30 +0000[diff] [blame]574 i64, ;; Size in bits
575 i64, ;; Alignment in bits
576 i64, ;; Offset in bits
Eric Christopher402e12a2011-12-16 23:42:33 +0000[diff] [blame]577 i32, ;; Flags to encode attributes, e.g. private
Devang Patele9db5e22011-04-16 00:11:51 +0000[diff] [blame]578 metadata, ;; Reference to type derived from
579 metadata, ;; (optional) Name of the Objective C property assoicated with
580 ;; Objective-C an ivar
581 metadata, ;; (optional) Name of the Objective C property getter selector.
582 metadata, ;; (optional) Name of the Objective C property setter selector.
583 i32 ;; (optional) Objective C property attributes.
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]584}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]585</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]586</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]587
588<p>These descriptors are used to define types derived from other types. The
589value of the tag varies depending on the meaning. The following are possible
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]590tag values:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]591
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]592<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]593<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]594DW_TAG_formal_parameter = 5
595DW_TAG_member = 13
596DW_TAG_pointer_type = 15
597DW_TAG_reference_type = 16
598DW_TAG_typedef = 22
599DW_TAG_const_type = 38
600DW_TAG_volatile_type = 53
601DW_TAG_restrict_type = 55
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]602</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]603</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]604
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]605<p><tt>DW_TAG_member</tt> is used to define a member of
606 a <a href="#format_composite_type">composite type</a>
607 or <a href="#format_subprograms">subprogram</a>. The type of the member is
608 the <a href="#format_derived_type">derived
609 type</a>. <tt>DW_TAG_formal_parameter</tt> is used to define a member which
610 is a formal argument of a subprogram.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]611
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]612<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]613
Eric Christopheradfc1ef2011-12-16 23:42:35 +0000[diff] [blame]614<p><tt>DW_TAG_pointer_type</tt>, <tt>DW_TAG_reference_type</tt>,
615 <tt>DW_TAG_const_type</tt>, <tt>DW_TAG_volatile_type</tt> and
616 <tt>DW_TAG_restrict_type</tt> are used to qualify
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]617 the <a href="#format_derived_type">derived type</a>. </p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]618
619<p><a href="#format_derived_type">Derived type</a> location can be determined
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]620 from the context and line number. The size, alignment and offset are
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]621 expressed in bits and can be 64 bit values. The alignment is used to round
622 the offset when embedded in a <a href="#format_composite_type">composite
623 type</a> (example to keep float doubles on 64 bit boundaries.) The offset is
624 the bit offset if embedded in a <a href="#format_composite_type">composite
625 type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]626
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]627<p>Note that the <tt>void *</tt> type is expressed as a type derived from NULL.
628</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]629
630</div>
631
632<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]633<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]634 <a name="format_composite_type">Composite type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]635</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]636
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]637<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]638
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]639<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]640<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]641!6 = metadata !{
642 i32, ;; Tag (see below)
643 metadata, ;; Reference to context
644 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]645 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]646 i32, ;; Line number where defined (may be 0)
647 i64, ;; Size in bits
648 i64, ;; Alignment in bits
649 i64, ;; Offset in bits
650 i32, ;; Flags
651 metadata, ;; Reference to type derived from
652 metadata, ;; Reference to array of member descriptors
653 i32 ;; Runtime languages
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]654}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]655</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]656</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]657
658<p>These descriptors are used to define types that are composed of 0 or more
659elements. The value of the tag varies depending on the meaning. The following
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]660are possible tag values:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]661
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]662<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]663<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]664DW_TAG_array_type = 1
665DW_TAG_enumeration_type = 4
666DW_TAG_structure_type = 19
667DW_TAG_union_type = 23
668DW_TAG_vector_type = 259
Bruno Cardoso Lopesd80ddc02009-05-29 17:08:57 +0000[diff] [blame]669DW_TAG_subroutine_type = 21
670DW_TAG_inheritance = 28
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]671</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]672</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]673
Jim Laskeyf8a01a92006-06-15 20:51:43 +0000[diff] [blame]674<p>The vector flag indicates that an array type is a native packed vector.</p>
675
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]676<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]677 (tag = <tt>DW_TAG_vector_type</tt>) are <a href="#format_subrange">subrange
678 descriptors</a>, each representing the range of subscripts at that level of
679 indexing.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]680
681<p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]682 <a href="#format_enumeration">enumerator descriptors</a>, each representing
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]683 the definition of enumeration value for the set. All enumeration type
684 descriptors are collected by named metadata <tt>!llvm.dbg.enum</tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]685
686<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]687 = <tt>DW_TAG_union_type</tt>) types are any one of
688 the <a href="#format_basic_type">basic</a>,
689 <a href="#format_derived_type">derived</a>
690 or <a href="#format_composite_type">composite</a> type descriptors, each
691 representing a field member of the structure or union.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]692
Jim Laskey4a9df242006-08-21 21:21:06 +0000[diff] [blame]693<p>For C++ classes (tag = <tt>DW_TAG_structure_type</tt>), member descriptors
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]694 provide information about base classes, static members and member
695 functions. If a member is a <a href="#format_derived_type">derived type
696 descriptor</a> and has a tag of <tt>DW_TAG_inheritance</tt>, then the type
697 represents a base class. If the member of is
698 a <a href="#format_global_variables">global variable descriptor</a> then it
699 represents a static member. And, if the member is
700 a <a href="#format_subprograms">subprogram descriptor</a> then it represents
701 a member function. For static members and member
702 functions, <tt>getName()</tt> returns the members link or the C++ mangled
703 name. <tt>getDisplayName()</tt> the simplied version of the name.</p>
Jim Laskey4a9df242006-08-21 21:21:06 +0000[diff] [blame]704
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]705<p>The first member of subroutine (tag = <tt>DW_TAG_subroutine_type</tt>) type
706 elements is the return type for the subroutine. The remaining elements are
707 the formal arguments to the subroutine.</p>
Jim Laskey094ee722006-06-20 21:13:20 +0000[diff] [blame]708
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]709<p><a href="#format_composite_type">Composite type</a> location can be
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]710 determined from the context and line number. The size, alignment and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]711 offset are expressed in bits and can be 64 bit values. The alignment is used
712 to round the offset when embedded in
713 a <a href="#format_composite_type">composite type</a> (as an example, to keep
714 float doubles on 64 bit boundaries.) The offset is the bit offset if embedded
715 in a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]716
717</div>
718
719<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]720<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]721 <a name="format_subrange">Subrange descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]722</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]723
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]724<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]725
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]726<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]727<pre>
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]728!42 = metadata !{
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]729 i32, ;; Tag = 33 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subrange_type)
730 i64, ;; Low value
731 i64 ;; High value
732}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]733</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]734</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]735
736<p>These descriptors are used to define ranges of array subscripts for an array
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]737 <a href="#format_composite_type">composite type</a>. The low value defines
738 the lower bounds typically zero for C/C++. The high value is the upper
739 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]740 > high the array bounds are not included in generated debugging information.
741</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]742
743</div>
744
745<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]746<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]747 <a name="format_enumeration">Enumerator descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]748</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]749
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]750<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]751
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]752<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]753<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]754!6 = metadata !{
755 i32, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
756 ;; (DW_TAG_enumerator)
757 metadata, ;; Name
758 i64 ;; Value
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]759}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]760</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]761</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]762
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]763<p>These descriptors are used to define members of an
764 enumeration <a href="#format_composite_type">composite type</a>, it
765 associates the name to the value.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]766
767</div>
768
769<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]770<h4>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]771 <a name="format_variables">Local variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]772</h4>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]773
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]774<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]775
776<div class="doc_code">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]777<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]778!7 = metadata !{
779 i32, ;; Tag (see below)
780 metadata, ;; Context
781 metadata, ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]782 metadata, ;; Reference to file where defined
Devang Patela83688f2011-03-08 16:29:40 +0000[diff] [blame]783 i32, ;; 24 bit - Line number where defined
784 ;; 8 bit - Argument number. 1 indicates 1st argument.
Devang Patel0a2a3062011-07-27 18:14:50 +0000[diff] [blame]785 metadata, ;; Type descriptor
786 i32, ;; flags
787 metadata ;; (optional) Reference to inline location
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]788}
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]789</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]790</div>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]791
792<p>These descriptors are used to define variables local to a sub program. The
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]793 value of the tag depends on the usage of the variable:</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]794
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]795<div class="doc_code">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]796<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]797DW_TAG_auto_variable = 256
798DW_TAG_arg_variable = 257
799DW_TAG_return_variable = 258
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]800</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]801</div>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]802
803<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]804 argument variable is any variable that appears as a formal argument to the
805 function. A return variable is used to track the result of a function and
806 has no source correspondent.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]807
Jim Laskey2d395d92006-03-24 09:20:27 +0000[diff] [blame]808<p>The context is either the subprogram or block where the variable is defined.
Devang Patel94c7ddb2011-08-16 22:09:43 +0000[diff] [blame]809 Name the source variable name. Context and line indicate where the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]810 variable was defined. Type descriptor defines the declared type of the
811 variable.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]812
813</div>
814
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]815</div>
816
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]817<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]818<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]819 <a name="format_common_intrinsics">Debugger intrinsic functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]820</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]821
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]822<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]823
824<p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]825 provide debug information at various points in generated code.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]826
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]827<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]828<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]829 <a name="format_common_declare">llvm.dbg.declare</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]830</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]831
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]832<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]833<pre>
Devang Patel4c7c0c62010-10-01 19:22:16 +0000[diff] [blame]834 void %<a href="#format_common_declare">llvm.dbg.declare</a>(metadata, metadata)
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]835</pre>
836
Jim Laskey2d395d92006-03-24 09:20:27 +0000[diff] [blame]837<p>This intrinsic provides information about a local element (ex. variable.) The
NAKAMURA Takumi4d6deb02011-04-09 09:51:57 +0000[diff] [blame]838 first argument is metadata holding alloca for the variable. The
Devang Patele136e502011-02-01 17:22:12 +0000[diff] [blame]839 second argument is metadata containing description of the variable. </p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]840</div>
841
842<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]843<h4>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]844 <a name="format_common_value">llvm.dbg.value</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]845</h4>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]846
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]847<div>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]848<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]849 void %<a href="#format_common_value">llvm.dbg.value</a>(metadata, i64, metadata)
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]850</pre>
851
852<p>This intrinsic provides information when a user source variable is set to a
853 new value. The first argument is the new value (wrapped as metadata). The
854 second argument is the offset in the user source variable where the new value
Devang Patele136e502011-02-01 17:22:12 +0000[diff] [blame]855 is written. The third argument is metadata containing description of the
856 user source variable. </p>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]857</div>
858
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]859</div>
860
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]861<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]862<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]863 <a name="format_common_lifetime">Object lifetimes and scoping</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]864</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]865
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]866<div>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]867<p>In many languages, the local variables in functions can have their lifetimes
868 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]869 for example, variables are only live (readable and writable) within the
870 source block that they are defined in. In functional languages, values are
871 only readable after they have been defined. Though this is a very obvious
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]872 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]873 scoping in this sense, and does not want to be tied to a language's scoping
874 rules.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]875
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]876<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]877 llvm instructions to encode line number and scoping information. Consider
878 the following C fragment, for example:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]879
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]880<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]881<pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8821. void foo() {
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8832. int X = 21;
8843. int Y = 22;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8854. {
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8865. int Z = 23;
8876. Z = X;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8887. }
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8898. X = Y;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8909. }
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]891</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]892</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]893
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]894<p>Compiled to LLVM, this function would be represented like this:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]895
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]896<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]897<pre>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]898define void @foo() nounwind ssp {
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]899entry:
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]900 %X = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
901 %Y = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
902 %Z = alloca i32, align 4 ; &lt;i32*&gt; [#uses=3]
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]903 %0 = bitcast i32* %X to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]904 call void @llvm.dbg.declare(metadata !{i32 * %X}, metadata !0), !dbg !7
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]905 store i32 21, i32* %X, !dbg !8
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]906 %1 = bitcast i32* %Y to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]907 call void @llvm.dbg.declare(metadata !{i32 * %Y}, metadata !9), !dbg !10
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]908 store i32 22, i32* %Y, !dbg !11
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]909 %2 = bitcast i32* %Z to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]910 call void @llvm.dbg.declare(metadata !{i32 * %Z}, metadata !12), !dbg !14
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]911 store i32 23, i32* %Z, !dbg !15
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]912 %tmp = load i32* %X, !dbg !16 ; &lt;i32&gt; [#uses=1]
913 %tmp1 = load i32* %Y, !dbg !16 ; &lt;i32&gt; [#uses=1]
914 %add = add nsw i32 %tmp, %tmp1, !dbg !16 ; &lt;i32&gt; [#uses=1]
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]915 store i32 %add, i32* %Z, !dbg !16
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]916 %tmp2 = load i32* %Y, !dbg !17 ; &lt;i32&gt; [#uses=1]
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]917 store i32 %tmp2, i32* %X, !dbg !17
918 ret void, !dbg !18
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]919}
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]920
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]921declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]922
923!0 = metadata !{i32 459008, metadata !1, metadata !"X",
924 metadata !3, i32 2, metadata !6}; [ DW_TAG_auto_variable ]
925!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
926!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo", metadata !"foo",
927 metadata !"foo", metadata !3, i32 1, metadata !4,
928 i1 false, i1 true}; [DW_TAG_subprogram ]
929!3 = metadata !{i32 458769, i32 0, i32 12, metadata !"foo.c",
930 metadata !"/private/tmp", metadata !"clang 1.1", i1 true,
931 i1 false, metadata !"", i32 0}; [DW_TAG_compile_unit ]
932!4 = metadata !{i32 458773, metadata !3, metadata !"", null, i32 0, i64 0, i64 0,
933 i64 0, i32 0, null, metadata !5, i32 0}; [DW_TAG_subroutine_type ]
934!5 = metadata !{null}
935!6 = metadata !{i32 458788, metadata !3, metadata !"int", metadata !3, i32 0,
936 i64 32, i64 32, i64 0, i32 0, i32 5}; [DW_TAG_base_type ]
937!7 = metadata !{i32 2, i32 7, metadata !1, null}
938!8 = metadata !{i32 2, i32 3, metadata !1, null}
939!9 = metadata !{i32 459008, metadata !1, metadata !"Y", metadata !3, i32 3,
940 metadata !6}; [ DW_TAG_auto_variable ]
941!10 = metadata !{i32 3, i32 7, metadata !1, null}
942!11 = metadata !{i32 3, i32 3, metadata !1, null}
943!12 = metadata !{i32 459008, metadata !13, metadata !"Z", metadata !3, i32 5,
944 metadata !6}; [ DW_TAG_auto_variable ]
945!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
946!14 = metadata !{i32 5, i32 9, metadata !13, null}
947!15 = metadata !{i32 5, i32 5, metadata !13, null}
948!16 = metadata !{i32 6, i32 5, metadata !13, null}
949!17 = metadata !{i32 8, i32 3, metadata !1, null}
950!18 = metadata !{i32 9, i32 1, metadata !2, null}
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]951</pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]952</div>
953
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]954<p>This example illustrates a few important details about LLVM debugging
955 information. In particular, it shows how the <tt>llvm.dbg.declare</tt>
956 intrinsic and location information, which are attached to an instruction,
957 are applied together to allow a debugger to analyze the relationship between
958 statements, variable definitions, and the code used to implement the
959 function.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]960
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]961<div class="doc_code">
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]962<pre>
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]963call void @llvm.dbg.declare(metadata, metadata !0), !dbg !7
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]964</pre>
965</div>
966
967<p>The first intrinsic
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]968 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]969 encodes debugging information for the variable <tt>X</tt>. The metadata
970 <tt>!dbg !7</tt> attached to the intrinsic provides scope information for the
971 variable <tt>X</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]972
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]973<div class="doc_code">
974<pre>
975!7 = metadata !{i32 2, i32 7, metadata !1, null}
976!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
977!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo",
978 metadata !"foo", metadata !"foo", metadata !3, i32 1,
979 metadata !4, i1 false, i1 true}; [DW_TAG_subprogram ]
980</pre>
981</div>
982
983<p>Here <tt>!7</tt> is metadata providing location information. It has four
984 fields: line number, column number, scope, and original scope. The original
985 scope represents inline location if this instruction is inlined inside a
986 caller, and is null otherwise. In this example, scope is encoded by
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]987 <tt>!1</tt>. <tt>!1</tt> represents a lexical block inside the scope
988 <tt>!2</tt>, where <tt>!2</tt> is a
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]989 <a href="#format_subprograms">subprogram descriptor</a>. This way the
990 location information attached to the intrinsics indicates that the
991 variable <tt>X</tt> is declared at line number 2 at a function level scope in
992 function <tt>foo</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]993
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]994<p>Now lets take another example.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]995
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]996<div class="doc_code">
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]997<pre>
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]998call void @llvm.dbg.declare(metadata, metadata !12), !dbg !14
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]999</pre>
1000</div>
1001
1002<p>The second intrinsic
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]1003 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]1004 encodes debugging information for variable <tt>Z</tt>. The metadata
1005 <tt>!dbg !14</tt> attached to the intrinsic provides scope information for
1006 the variable <tt>Z</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1007
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]1008<div class="doc_code">
1009<pre>
1010!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
1011!14 = metadata !{i32 5, i32 9, metadata !13, null}
1012</pre>
1013</div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1014
John Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]1015<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]1016 column number 9 inside of lexical scope <tt>!13</tt>. The lexical scope
1017 itself resides inside of lexical scope <tt>!1</tt> described above.</p>
1018
1019<p>The scope information attached with each instruction provides a
1020 straightforward way to find instructions covered by a scope.</p>
1021
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1022</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1023
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1024</div>
1025
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1026<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1027<h2>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1028 <a name="ccxx_frontend">C/C++ front-end specific debug information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1029</h2>
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]1030<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1031
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1032<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1033
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1034<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]1035 that is effectively identical
1036 to <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3.0</a> in
1037 terms of information content. This allows code generators to trivially
1038 support native debuggers by generating standard dwarf information, and
1039 contains enough information for non-dwarf targets to translate it as
1040 needed.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1041
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1042<p>This section describes the forms used to represent C and C++ programs. Other
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1043 languages could pattern themselves after this (which itself is tuned to
1044 representing programs in the same way that DWARF 3 does), or they could
1045 choose to provide completely different forms if they don't fit into the DWARF
1046 model. As support for debugging information gets added to the various LLVM
1047 source-language front-ends, the information used should be documented
1048 here.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1049
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1050<p>The following sections provide examples of various C/C++ constructs and the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1051 debug information that would best describe those constructs.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1052
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1053<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1054<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1055 <a name="ccxx_compile_units">C/C++ source file information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1056</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1057
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1058<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1059
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1060<p>Given the source files <tt>MySource.cpp</tt> and <tt>MyHeader.h</tt> located
1061 in the directory <tt>/Users/mine/sources</tt>, the following code:</p>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1062
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1063<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1064<pre>
1065#include "MyHeader.h"
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1066
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1067int main(int argc, char *argv[]) {
1068 return 0;
1069}
1070</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1071</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1072
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1073<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1074
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1075<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1076<pre>
1077...
1078;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1079;; Define the compile unit for the main source file "/Users/mine/sources/MySource.cpp".
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1080;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1081!2 = metadata !{
1082 i32 524305, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1083 i32 0, ;; Unused
1084 i32 4, ;; Language Id
1085 metadata !"MySource.cpp",
1086 metadata !"/Users/mine/sources",
1087 metadata !"4.2.1 (Based on Apple Inc. build 5649) (LLVM build 00)",
1088 i1 true, ;; Main Compile Unit
1089 i1 false, ;; Optimized compile unit
1090 metadata !"", ;; Compiler flags
1091 i32 0} ;; Runtime version
1092
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1093;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1094;; Define the file for the file "/Users/mine/sources/MySource.cpp".
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1095;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1096!1 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1097 i32 524329, ;; Tag
1098 metadata !"MySource.cpp",
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1099 metadata !"/Users/mine/sources",
Devang Patel9fea9c22010-07-13 16:53:20 +0000[diff] [blame]1100 metadata !2 ;; Compile unit
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1101}
1102
1103;;
1104;; Define the file for the file "/Users/mine/sources/Myheader.h"
1105;;
1106!3 = metadata !{
1107 i32 524329, ;; Tag
1108 metadata !"Myheader.h"
1109 metadata !"/Users/mine/sources",
Devang Patel9fea9c22010-07-13 16:53:20 +0000[diff] [blame]1110 metadata !2 ;; Compile unit
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1111}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1112
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1113...
1114</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1115</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1116
Devang Pateld98ec5f2010-03-26 19:08:36 +0000[diff] [blame]1117<p>llvm::Instruction provides easy access to metadata attached with an
1118instruction. One can extract line number information encoded in LLVM IR
1119using <tt>Instruction::getMetadata()</tt> and
1120<tt>DILocation::getLineNumber()</tt>.
1121<pre>
1122 if (MDNode *N = I->getMetadata("dbg")) { // Here I is an LLVM instruction
1123 DILocation Loc(N); // DILocation is in DebugInfo.h
1124 unsigned Line = Loc.getLineNumber();
1125 StringRef File = Loc.getFilename();
1126 StringRef Dir = Loc.getDirectory();
1127 }
1128</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1129</div>
1130
1131<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1132<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1133 <a name="ccxx_global_variable">C/C++ global variable information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1134</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1135
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1136<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1137
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1138<p>Given an integer global variable declared as follows:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1139
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1140<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1141<pre>
1142int MyGlobal = 100;
1143</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1144</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1145
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1146<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1147
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1148<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1149<pre>
1150;;
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1151;; Define the global itself.
1152;;
1153%MyGlobal = global int 100
1154...
1155;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1156;; List of debug info of globals
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1157;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1158!llvm.dbg.gv = !{!0}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1159
1160;;
1161;; Define the global variable descriptor. Note the reference to the global
1162;; variable anchor and the global variable itself.
1163;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1164!0 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1165 i32 524340, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1166 i32 0, ;; Unused
1167 metadata !1, ;; Context
1168 metadata !"MyGlobal", ;; Name
1169 metadata !"MyGlobal", ;; Display Name
1170 metadata !"MyGlobal", ;; Linkage Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1171 metadata !3, ;; Compile Unit
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1172 i32 1, ;; Line Number
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1173 metadata !4, ;; Type
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1174 i1 false, ;; Is a local variable
1175 i1 true, ;; Is this a definition
1176 i32* @MyGlobal ;; The global variable
1177}
1178
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1179;;
1180;; Define the basic type of 32 bit signed integer. Note that since int is an
1181;; intrinsic type the source file is NULL and line 0.
1182;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1183!4 = metadata !{
1184 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1185 metadata !1, ;; Context
1186 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1187 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1188 i32 0, ;; Line number
1189 i64 32, ;; Size in Bits
1190 i64 32, ;; Align in Bits
1191 i64 0, ;; Offset in Bits
1192 i32 0, ;; Flags
1193 i32 5 ;; Encoding
1194}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1195
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1196</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1197</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1198
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1199</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1200
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1201<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1202<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1203 <a name="ccxx_subprogram">C/C++ function information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1204</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1205
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1206<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1207
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1208<p>Given a function declared as follows:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1209
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1210<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1211<pre>
1212int main(int argc, char *argv[]) {
1213 return 0;
1214}
1215</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1216</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1217
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1218<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1219
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1220<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1221<pre>
1222;;
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1223;; Define the anchor for subprograms. Note that the second field of the
1224;; anchor is 46, which is the same as the tag for subprograms
1225;; (46 = DW_TAG_subprogram.)
1226;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1227!6 = metadata !{
1228 i32 524334, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1229 i32 0, ;; Unused
1230 metadata !1, ;; Context
1231 metadata !"main", ;; Name
1232 metadata !"main", ;; Display name
1233 metadata !"main", ;; Linkage name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1234 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1235 i32 1, ;; Line number
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1236 metadata !4, ;; Type
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1237 i1 false, ;; Is local
Devang Patelda194752011-04-05 22:52:06 +0000[diff] [blame]1238 i1 true, ;; Is definition
1239 i32 0, ;; Virtuality attribute, e.g. pure virtual function
1240 i32 0, ;; Index into virtual table for C++ methods
1241 i32 0, ;; Type that holds virtual table.
1242 i32 0, ;; Flags
1243 i1 false, ;; True if this function is optimized
1244 Function *, ;; Pointer to llvm::Function
1245 null ;; Function template parameters
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1246}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1247;;
1248;; Define the subprogram itself.
1249;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1250define i32 @main(i32 %argc, i8** %argv) {
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1251...
1252}
1253</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1254</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1255
1256</div>
1257
1258<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1259<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1260 <a name="ccxx_basic_types">C/C++ basic types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1261</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1262
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1263<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1264
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1265<p>The following are the basic type descriptors for C/C++ core types:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1266
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1267<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1268<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1269 <a name="ccxx_basic_type_bool">bool</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1270</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1271
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1272<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1273
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1274<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1275<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1276!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1277 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1278 metadata !1, ;; Context
1279 metadata !"bool", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1280 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1281 i32 0, ;; Line number
1282 i64 8, ;; Size in Bits
1283 i64 8, ;; Align in Bits
1284 i64 0, ;; Offset in Bits
1285 i32 0, ;; Flags
1286 i32 2 ;; Encoding
1287}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1288</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1289</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1290
1291</div>
1292
1293<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1294<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1295 <a name="ccxx_basic_char">char</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1296</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1297
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1298<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1299
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1300<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1301<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1302!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1303 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1304 metadata !1, ;; Context
1305 metadata !"char", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1306 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1307 i32 0, ;; Line number
1308 i64 8, ;; Size in Bits
1309 i64 8, ;; Align in Bits
1310 i64 0, ;; Offset in Bits
1311 i32 0, ;; Flags
1312 i32 6 ;; Encoding
1313}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1314</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1315</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1316
1317</div>
1318
1319<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1320<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1321 <a name="ccxx_basic_unsigned_char">unsigned char</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1322</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1323
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1324<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1325
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1326<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1327<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1328!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1329 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1330 metadata !1, ;; Context
1331 metadata !"unsigned char",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1332 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1333 i32 0, ;; Line number
1334 i64 8, ;; Size in Bits
1335 i64 8, ;; Align in Bits
1336 i64 0, ;; Offset in Bits
1337 i32 0, ;; Flags
1338 i32 8 ;; Encoding
1339}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1340</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1341</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1342
1343</div>
1344
1345<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1346<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1347 <a name="ccxx_basic_short">short</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1348</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1349
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1350<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1351
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1352<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1353<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1354!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1355 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1356 metadata !1, ;; Context
1357 metadata !"short int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1358 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1359 i32 0, ;; Line number
1360 i64 16, ;; Size in Bits
1361 i64 16, ;; Align in Bits
1362 i64 0, ;; Offset in Bits
1363 i32 0, ;; Flags
1364 i32 5 ;; Encoding
1365}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1366</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1367</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1368
1369</div>
1370
1371<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1372<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1373 <a name="ccxx_basic_unsigned_short">unsigned short</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1374</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1375
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1376<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1377
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1378<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1379<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1380!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1381 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1382 metadata !1, ;; Context
1383 metadata !"short unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1384 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1385 i32 0, ;; Line number
1386 i64 16, ;; Size in Bits
1387 i64 16, ;; Align in Bits
1388 i64 0, ;; Offset in Bits
1389 i32 0, ;; Flags
1390 i32 7 ;; Encoding
1391}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1392</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1393</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1394
1395</div>
1396
1397<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1398<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1399 <a name="ccxx_basic_int">int</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1400</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1401
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1402<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1403
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1404<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1405<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1406!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1407 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1408 metadata !1, ;; Context
1409 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1410 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1411 i32 0, ;; Line number
1412 i64 32, ;; Size in Bits
1413 i64 32, ;; Align in Bits
1414 i64 0, ;; Offset in Bits
1415 i32 0, ;; Flags
1416 i32 5 ;; Encoding
1417}
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1418</pre></div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1419
1420</div>
1421
1422<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1423<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1424 <a name="ccxx_basic_unsigned_int">unsigned int</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1425</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1426
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1427<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1428
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1429<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1430<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1431!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1432 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1433 metadata !1, ;; Context
1434 metadata !"unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1435 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1436 i32 0, ;; Line number
1437 i64 32, ;; Size in Bits
1438 i64 32, ;; Align in Bits
1439 i64 0, ;; Offset in Bits
1440 i32 0, ;; Flags
1441 i32 7 ;; Encoding
1442}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1443</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1444</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1445
1446</div>
1447
1448<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1449<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1450 <a name="ccxx_basic_long_long">long long</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1451</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1452
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1453<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1454
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1455<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1456<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1457!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1458 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1459 metadata !1, ;; Context
1460 metadata !"long long int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1461 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1462 i32 0, ;; Line number
1463 i64 64, ;; Size in Bits
1464 i64 64, ;; Align in Bits
1465 i64 0, ;; Offset in Bits
1466 i32 0, ;; Flags
1467 i32 5 ;; Encoding
1468}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1469</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1470</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1471
1472</div>
1473
1474<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1475<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1476 <a name="ccxx_basic_unsigned_long_long">unsigned long long</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1477</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1478
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1479<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1480
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1481<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1482<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1483!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1484 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1485 metadata !1, ;; Context
1486 metadata !"long long unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1487 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1488 i32 0, ;; Line number
1489 i64 64, ;; Size in Bits
1490 i64 64, ;; Align in Bits
1491 i64 0, ;; Offset in Bits
1492 i32 0, ;; Flags
1493 i32 7 ;; Encoding
1494}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1495</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1496</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1497
1498</div>
1499
1500<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1501<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1502 <a name="ccxx_basic_float">float</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1503</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1504
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1505<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1506
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1507<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1508<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1509!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1510 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1511 metadata !1, ;; Context
1512 metadata !"float",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1513 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1514 i32 0, ;; Line number
1515 i64 32, ;; Size in Bits
1516 i64 32, ;; Align in Bits
1517 i64 0, ;; Offset in Bits
1518 i32 0, ;; Flags
1519 i32 4 ;; Encoding
1520}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1521</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1522</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1523
1524</div>
1525
1526<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1527<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1528 <a name="ccxx_basic_double">double</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1529</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1530
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1531<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1532
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1533<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1534<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1535!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1536 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1537 metadata !1, ;; Context
1538 metadata !"double",;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1539 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1540 i32 0, ;; Line number
1541 i64 64, ;; Size in Bits
1542 i64 64, ;; Align in Bits
1543 i64 0, ;; Offset in Bits
1544 i32 0, ;; Flags
1545 i32 4 ;; Encoding
1546}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1547</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1548</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1549
1550</div>
1551
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1552</div>
1553
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1554<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1555<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1556 <a name="ccxx_derived_types">C/C++ derived types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1557</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1558
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1559<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1560
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1561<p>Given the following as an example of C/C++ derived type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1562
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1563<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1564<pre>
1565typedef const int *IntPtr;
1566</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1567</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1568
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1569<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1570
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1571<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1572<pre>
1573;;
1574;; Define the typedef "IntPtr".
1575;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1576!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1577 i32 524310, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1578 metadata !1, ;; Context
1579 metadata !"IntPtr", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1580 metadata !3, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1581 i32 0, ;; Line number
1582 i64 0, ;; Size in bits
1583 i64 0, ;; Align in bits
1584 i64 0, ;; Offset in bits
1585 i32 0, ;; Flags
1586 metadata !4 ;; Derived From type
1587}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1588
1589;;
1590;; Define the pointer type.
1591;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1592!4 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1593 i32 524303, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1594 metadata !1, ;; Context
1595 metadata !"", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1596 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1597 i32 0, ;; Line number
1598 i64 64, ;; Size in bits
1599 i64 64, ;; Align in bits
1600 i64 0, ;; Offset in bits
1601 i32 0, ;; Flags
1602 metadata !5 ;; Derived From type
1603}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1604;;
1605;; Define the const type.
1606;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1607!5 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1608 i32 524326, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1609 metadata !1, ;; Context
1610 metadata !"", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1611 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1612 i32 0, ;; Line number
1613 i64 32, ;; Size in bits
1614 i64 32, ;; Align in bits
1615 i64 0, ;; Offset in bits
1616 i32 0, ;; Flags
1617 metadata !6 ;; Derived From type
1618}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1619;;
1620;; Define the int type.
1621;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1622!6 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1623 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1624 metadata !1, ;; Context
1625 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1626 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1627 i32 0, ;; Line number
1628 i64 32, ;; Size in bits
1629 i64 32, ;; Align in bits
1630 i64 0, ;; Offset in bits
1631 i32 0, ;; Flags
1632 5 ;; Encoding
1633}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1634</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1635</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1636
1637</div>
1638
1639<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1640<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1641 <a name="ccxx_composite_types">C/C++ struct/union types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1642</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1643
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1644<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1645
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1646<p>Given the following as an example of C/C++ struct type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1647
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1648<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1649<pre>
1650struct Color {
1651 unsigned Red;
1652 unsigned Green;
1653 unsigned Blue;
1654};
1655</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1656</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1657
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1658<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1659
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1660<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1661<pre>
1662;;
1663;; Define basic type for unsigned int.
1664;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1665!5 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1666 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1667 metadata !1, ;; Context
1668 metadata !"unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1669 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1670 i32 0, ;; Line number
1671 i64 32, ;; Size in Bits
1672 i64 32, ;; Align in Bits
1673 i64 0, ;; Offset in Bits
1674 i32 0, ;; Flags
1675 i32 7 ;; Encoding
1676}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1677;;
1678;; Define composite type for struct Color.
1679;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1680!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1681 i32 524307, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1682 metadata !1, ;; Context
1683 metadata !"Color", ;; Name
1684 metadata !1, ;; Compile unit
1685 i32 1, ;; Line number
1686 i64 96, ;; Size in bits
1687 i64 32, ;; Align in bits
1688 i64 0, ;; Offset in bits
1689 i32 0, ;; Flags
1690 null, ;; Derived From
1691 metadata !3, ;; Elements
1692 i32 0 ;; Runtime Language
1693}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1694
1695;;
1696;; Define the Red field.
1697;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1698!4 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1699 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1700 metadata !1, ;; Context
1701 metadata !"Red", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1702 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1703 i32 2, ;; Line number
1704 i64 32, ;; Size in bits
1705 i64 32, ;; Align in bits
1706 i64 0, ;; Offset in bits
1707 i32 0, ;; Flags
1708 metadata !5 ;; Derived From type
1709}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1710
1711;;
1712;; Define the Green field.
1713;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1714!6 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1715 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1716 metadata !1, ;; Context
1717 metadata !"Green", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1718 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1719 i32 3, ;; Line number
1720 i64 32, ;; Size in bits
1721 i64 32, ;; Align in bits
1722 i64 32, ;; Offset in bits
1723 i32 0, ;; Flags
1724 metadata !5 ;; Derived From type
1725}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1726
1727;;
1728;; Define the Blue field.
1729;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1730!7 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1731 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1732 metadata !1, ;; Context
1733 metadata !"Blue", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1734 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1735 i32 4, ;; Line number
1736 i64 32, ;; Size in bits
1737 i64 32, ;; Align in bits
1738 i64 64, ;; Offset in bits
1739 i32 0, ;; Flags
1740 metadata !5 ;; Derived From type
1741}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1742
1743;;
1744;; Define the array of fields used by the composite type Color.
1745;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1746!3 = metadata !{metadata !4, metadata !6, metadata !7}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1747</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1748</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1749
1750</div>
1751
1752<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1753<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1754 <a name="ccxx_enumeration_types">C/C++ enumeration types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1755</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1756
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1757<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1758
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1759<p>Given the following as an example of C/C++ enumeration type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1760
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1761<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1762<pre>
1763enum Trees {
1764 Spruce = 100,
1765 Oak = 200,
1766 Maple = 300
1767};
1768</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1769</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1770
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1771<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1772
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1773<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1774<pre>
1775;;
1776;; Define composite type for enum Trees
1777;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1778!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1779 i32 524292, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1780 metadata !1, ;; Context
1781 metadata !"Trees", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1782 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1783 i32 1, ;; Line number
1784 i64 32, ;; Size in bits
1785 i64 32, ;; Align in bits
1786 i64 0, ;; Offset in bits
1787 i32 0, ;; Flags
1788 null, ;; Derived From type
1789 metadata !3, ;; Elements
1790 i32 0 ;; Runtime language
1791}
Devang Patel2a610c72009-08-25 05:24:07 +0000[diff] [blame]1792
Devang Patel82459882009-08-26 05:01:18 +0000[diff] [blame]1793;;
1794;; Define the array of enumerators used by composite type Trees.
1795;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1796!3 = metadata !{metadata !4, metadata !5, metadata !6}
1797
1798;;
1799;; Define Spruce enumerator.
1800;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1801!4 = metadata !{i32 524328, metadata !"Spruce", i64 100}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1802
1803;;
1804;; Define Oak enumerator.
1805;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1806!5 = metadata !{i32 524328, metadata !"Oak", i64 200}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1807
1808;;
1809;; Define Maple enumerator.
1810;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1811!6 = metadata !{i32 524328, metadata !"Maple", i64 300}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1812
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1813</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1814</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1815
1816</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1817
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1818</div>
1819
Devang Patel6ac5b162011-11-15 22:59:54 +0000[diff] [blame]1820
1821<!-- *********************************************************************** -->
1822<h2>
1823 <a name="llvmdwarfextension">Debugging information format</a>
1824</h2>
1825<!-- *********************************************************************** -->
1826<div>
1827<!-- ======================================================================= -->
1828<h3>
1829 <a name="objcproperty">Debugging Information Extension for Objective C
1830Properties</a></li>
1831</h3>
1832<div>
1833<!-- *********************************************************************** -->
1834<h4>
1835 <a name="objcpropertyintroduction">Introduction</a>
1836</h4>
1837<!-- *********************************************************************** -->
1838
1839<div>
1840<p>Objective C provides a simpler way to declare and define accessor methods
1841using declared properties. The language provides features to declare a
1842property and to let compiler synthesize accessor methods.
1843</p>
1844
1845<p>The debugger lets developer inspect Objective C interfaces and their
1846instance variables and class variables. However, the debugger does not know
1847anything about the properties defined in Objective C interfaces. The debugger
1848consumes information generated by compiler in DWARF format. The format does
1849not support encoding of Objective C properties. This proposal describes DWARF
1850extensions to encode Objective C properties, which the debugger can use to let
1851developers inspect Objective C properties.
1852</p>
1853
1854</div>
1855
1856
1857<!-- *********************************************************************** -->
1858<h4>
1859 <a name="objcpropertyproposal">Proposal</a>
1860</h4>
1861<!-- *********************************************************************** -->
1862
1863<div>
1864<p>Objective C properties are always backed by an instance variable. The
1865instance variables backing properties are identified using
1866DW_AT_APPLE_property_name attribute. The instance variables with this
1867attribute may not have data location attributes. The location of instance
1868variables is determined by debugger only after consulting Objective C runtime.
1869</p>
1870
1871<div class="doc_code">
1872<pre>
1873@interface I1 {
1874 int n2;
1875}
1876
1877@property p1;
1878@property p2;
1879@end
1880
1881@implementation I1
1882@synthesize p1;
1883@synthesize p2 = n2;
1884@end
1885
1886
1887TAG_structure_type [7] *
1888 AT_APPLE_runtime_class( 0x10 )
1889 AT_name( "I1" )
1890 AT_decl_file( "Objc_Property.m" )
1891 AT_decl_line( 3 )
1892
1893 TAG_member [8]
1894 AT_name( "p1" )
1895 AT_APPLE_property_name(“p1”)
1896 AT_type( {0x00000147} ( int ) )
1897
1898 TAG_member [8]
1899 AT_name( "n2" )
1900 AT_APPLE_property_name(“p2”)
1901 AT_type( {0x00000147} ( int ) )
1902</pre>
1903</div>
1904
1905<p> Developers can decorate a property with attributes which are encoded using
1906DW_AT_APPLE_property_attribute.
1907</p>
1908
1909<div class="doc_code">
1910<pre>
1911@property (readonly, nonatomic) int pr;
1912
1913
1914TAG_member [8]
1915 AT_name(“pr”)
1916 AT_APPLE_property_name(“pr”)
1917 AT_type ( {0x00000147} (int) )
1918 AT_APPLE_property_attribute (DW_APPLE_PROPERTY_readonly, DW_APPLE_PROPERTY_nonatomic)
1919</pre>
1920</div>
1921
1922<p> The setter and getter method names are attached to the property using
1923DW_AT_APPLE_property_setter and DW_AT_APPLE_property_getter attributes.
1924</p>
1925<div class="doc_code">
1926<pre>
1927@interface I1
1928@property (setter=myOwnP3Setter:) int p3;
1929-(void)myOwnP3Setter:(int)a;
1930@end
1931
1932@implementation I1
1933@synthesize p3;
1934-(void)myOwnP3Setter:(int)a{ }
1935@end
1936
19370x000003bd: TAG_structure_type [7] *
1938 AT_APPLE_runtime_class( 0x10 )
1939 AT_name( "I1" )
1940 AT_decl_file( "Objc_Property.m" )
1941 AT_decl_line( 3 )
19420x000003f3: TAG_member [8]
1943 AT_name( "p3" )
1944 AT_APPLE_property_name(“p3”)
1945 AT_APPLE_property_setter(“myOwnP3Setter:”)
1946 AT_type( {0x00000147} ( int ) )
1947</pre>
1948</div>
1949
1950</div>
1951
1952<!-- *********************************************************************** -->
1953<h4>
1954 <a name="objcpropertynewattributes">New DWARF Attributes</a>
1955</h4>
1956<!-- *********************************************************************** -->
1957
1958<div>
1959<table border="1" cellspacing="0">
1960 <tr>
1961 <th width=200 >Attribute</th>
1962 <th width=200 >Value</th>
1963 <th width=200 >Classes</th>
1964 </tr>
1965 <tr>
1966 <td width=200 >DW_AT_APPLE_property_name</td>
1967 <td width=200 >0x3fe8</td>
1968 <td width=200 >String</td>
1969 </tr>
1970 <tr>
1971 <td width=200 >DW_AT_APPLE_property_getter</td>
1972 <td width=200 >0x3fe9</td>
1973 <td width=200 >String</td>
1974 </tr>
1975 <tr>
1976 <td width=200 >DW_AT_APPLE_property_setter</td>
1977 <td width=200 >0x3fea</td>
1978 <td width=200 >String</td>
1979 </tr>
1980 <tr>
1981 <td width=200 >DW_AT_APPLE_property_attribute</td>
1982 <td width=200 >0x3feb</td>
1983 <td width=200 >Constant</td>
1984 </tr>
1985</table>
1986
1987</div>
1988
1989<!-- *********************************************************************** -->
1990<h4>
1991 <a name="objcpropertynewconstants">New DWARF Constants</a>
1992</h4>
1993<!-- *********************************************************************** -->
1994
1995<div>
1996<table border="1" cellspacing="0">
1997 <tr>
1998 <th width=200 >Name</th>
1999 <th width=200 >Value</th>
2000 </tr>
2001 <tr>
2002 <td width=200 >DW_AT_APPLE_PROPERTY_readonly</td>
2003 <td width=200 >0x1</td>
2004 </tr>
2005 <tr>
2006 <td width=200 >DW_AT_APPLE_PROPERTY_readwrite</td>
2007 <td width=200 >0x2</td>
2008 </tr>
2009 <tr>
2010 <td width=200 >DW_AT_APPLE_PROPERTY_assign</td>
2011 <td width=200 >0x4</td>
2012 </tr>
2013 <tr>
2014 <td width=200 >DW_AT_APPLE_PROPERTY_retain</td>
2015 <td width=200 >0x8</td>
2016 </tr>
2017 <tr>
2018 <td width=200 >DW_AT_APPLE_PROPERTY_copy</td>
2019 <td width=200 >0x10</td>
2020 </tr>
2021 <tr>
2022 <td width=200 >DW_AT_APPLE_PROPERTY_nonatomic</td>
2023 <td width=200 >0x20</td>
2024 </tr>
2025</table>
2026
2027</div>
2028</div>
2029</div>
2030
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]2031<!-- *********************************************************************** -->
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Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]2033<hr>
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2040 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]2041 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
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