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Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]6 <title>Source Level Debugging with LLVM</title>
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10
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]11<h1>Source Level Debugging with LLVM</h1>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]12
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]13<table class="layout" style="width:100%">
14 <tr class="layout">
15 <td class="left">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]16<ul>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]17 <li><a href="#introduction">Introduction</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]18 <ol>
19 <li><a href="#phil">Philosophy behind LLVM debugging information</a></li>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]20 <li><a href="#consumers">Debug information consumers</a></li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]21 <li><a href="#debugopt">Debugging optimized code</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]22 </ol></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]23 <li><a href="#format">Debugging information format</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]24 <ol>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]25 <li><a href="#debug_info_descriptors">Debug information descriptors</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]26 <ul>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]27 <li><a href="#format_compile_units">Compile unit descriptors</a></li>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]28 <li><a href="#format_files">File descriptors</a></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]29 <li><a href="#format_global_variables">Global variable descriptors</a></li>
30 <li><a href="#format_subprograms">Subprogram descriptors</a></li>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]31 <li><a href="#format_blocks">Block descriptors</a></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]32 <li><a href="#format_basic_type">Basic type descriptors</a></li>
33 <li><a href="#format_derived_type">Derived type descriptors</a></li>
34 <li><a href="#format_composite_type">Composite type descriptors</a></li>
35 <li><a href="#format_subrange">Subrange descriptors</a></li>
36 <li><a href="#format_enumeration">Enumerator descriptors</a></li>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]37 <li><a href="#format_variables">Local variables</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]38 </ul></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]39 <li><a href="#format_common_intrinsics">Debugger intrinsic functions</a>
40 <ul>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]41 <li><a href="#format_common_declare">llvm.dbg.declare</a></li>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]42 <li><a href="#format_common_value">llvm.dbg.value</a></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]43 </ul></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]44 </ol></li>
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]45 <li><a href="#format_common_lifetime">Object lifetimes and scoping</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]46 <li><a href="#ccxx_frontend">C/C++ front-end specific debug information</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]47 <ol>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]48 <li><a href="#ccxx_compile_units">C/C++ source file information</a></li>
49 <li><a href="#ccxx_global_variable">C/C++ global variable information</a></li>
50 <li><a href="#ccxx_subprogram">C/C++ function information</a></li>
51 <li><a href="#ccxx_basic_types">C/C++ basic types</a></li>
52 <li><a href="#ccxx_derived_types">C/C++ derived types</a></li>
53 <li><a href="#ccxx_composite_types">C/C++ struct/union types</a></li>
54 <li><a href="#ccxx_enumeration_types">C/C++ enumeration types</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]55 </ol></li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]56</ul>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]57</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]58<td class="right">
Misha Brukmane849a1a2004-05-12 21:26:16 +0000[diff] [blame]59<img src="img/venusflytrap.jpg" alt="A leafy and green bug eater" width="247"
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]60height="369">
61</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]62</tr></table>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]63
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]64<div class="doc_author">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]65 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
Jim Laskeyc760a922007-03-14 19:32:21 +0000[diff] [blame]66 and <a href="mailto:jlaskey@mac.com">Jim Laskey</a></p>
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]67</div>
68
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]69
70<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]71<h2><a name="introduction">Introduction</a></h2>
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]72<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]73
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]74<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]75
76<p>This document is the central repository for all information pertaining to
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]77 debug information in LLVM. It describes the <a href="#format">actual format
78 that the LLVM debug information</a> takes, which is useful for those
79 interested in creating front-ends or dealing directly with the information.
Chris Lattner8ad2f982009-07-18 21:47:15 +0000[diff] [blame]80 Further, this document provides specific examples of what debug information
Chris Lattner89940752011-01-18 06:12:10 +0000[diff] [blame]81 for C/C++ looks like.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]82
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]83<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]84<h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]85 <a name="phil">Philosophy behind LLVM debugging information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]86</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]87
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]88<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]89
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]90<p>The idea of the LLVM debugging information is to capture how the important
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]91 pieces of the source-language's Abstract Syntax Tree map onto LLVM code.
92 Several design aspects have shaped the solution that appears here. The
93 important ones are:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]94
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]95<ul>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]96 <li>Debugging information should have very little impact on the rest of the
97 compiler. No transformations, analyses, or code generators should need to
98 be modified because of debugging information.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]99
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]100 <li>LLVM optimizations should interact in <a href="#debugopt">well-defined and
101 easily described ways</a> with the debugging information.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]102
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]103 <li>Because LLVM is designed to support arbitrary programming languages,
104 LLVM-to-LLVM tools should not need to know anything about the semantics of
105 the source-level-language.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]106
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]107 <li>Source-level languages are often <b>widely</b> different from one another.
108 LLVM should not put any restrictions of the flavor of the source-language,
109 and the debugging information should work with any language.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]110
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]111 <li>With code generator support, it should be possible to use an LLVM compiler
112 to compile a program to native machine code and standard debugging
113 formats. This allows compatibility with traditional machine-code level
114 debuggers, like GDB or DBX.</li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]115</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]116
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]117<p>The approach used by the LLVM implementation is to use a small set
118 of <a href="#format_common_intrinsics">intrinsic functions</a> to define a
119 mapping between LLVM program objects and the source-level objects. The
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]120 description of the source-level program is maintained in LLVM metadata
121 in an <a href="#ccxx_frontend">implementation-defined format</a>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]122 (the C/C++ front-end currently uses working draft 7 of
123 the <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3
124 standard</a>).</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]125
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]126<p>When a program is being debugged, a debugger interacts with the user and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]127 turns the stored debug information into source-language specific information.
128 As such, a debugger must be aware of the source-language, and is thus tied to
129 a specific language or family of languages.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]130
131</div>
132
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]133<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]134<h3>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]135 <a name="consumers">Debug information consumers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]136</h3>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]137
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]138<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]139
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]140<p>The role of debug information is to provide meta information normally
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]141 stripped away during the compilation process. This meta information provides
142 an LLVM user a relationship between generated code and the original program
143 source code.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]144
Chris Lattnerc3107782010-04-05 04:11:11 +0000[diff] [blame]145<p>Currently, debug information is consumed by DwarfDebug to produce dwarf
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]146 information used by the gdb debugger. Other targets could use the same
147 information to produce stabs or other debug forms.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]148
149<p>It would also be reasonable to use debug information to feed profiling tools
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]150 for analysis of generated code, or, tools for reconstructing the original
151 source from generated code.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]152
153<p>TODO - expound a bit more.</p>
154
155</div>
156
157<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]158<h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]159 <a name="debugopt">Debugging optimized code</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]160</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]161
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]162<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]163
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]164<p>An extremely high priority of LLVM debugging information is to make it
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]165 interact well with optimizations and analysis. In particular, the LLVM debug
166 information provides the following guarantees:</p>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]167
168<ul>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]169 <li>LLVM debug information <b>always provides information to accurately read
170 the source-level state of the program</b>, regardless of which LLVM
171 optimizations have been run, and without any modification to the
172 optimizations themselves. However, some optimizations may impact the
173 ability to modify the current state of the program with a debugger, such
174 as setting program variables, or calling functions that have been
175 deleted.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]176
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]177 <li>As desired, LLVM optimizations can be upgraded to be aware of the LLVM
178 debugging information, allowing them to update the debugging information
179 as they perform aggressive optimizations. This means that, with effort,
180 the LLVM optimizers could optimize debug code just as well as non-debug
181 code.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]182
Devang Patele0bdc592011-05-31 17:45:27 +0000[diff] [blame]183 <li>LLVM debug information does not prevent optimizations from
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]184 happening (for example inlining, basic block reordering/merging/cleanup,
Devang Patelf729e912011-05-31 18:06:14 +0000[diff] [blame]185 tail duplication, etc).</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]186
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]187 <li>LLVM debug information is automatically optimized along with the rest of
188 the program, using existing facilities. For example, duplicate
189 information is automatically merged by the linker, and unused information
190 is automatically removed.</li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]191</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]192
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]193<p>Basically, the debug information allows you to compile a program with
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]194 "<tt>-O0 -g</tt>" and get full debug information, allowing you to arbitrarily
195 modify the program as it executes from a debugger. Compiling a program with
196 "<tt>-O3 -g</tt>" gives you full debug information that is always available
197 and accurate for reading (e.g., you get accurate stack traces despite tail
198 call elimination and inlining), but you might lose the ability to modify the
199 program and call functions where were optimized out of the program, or
200 inlined away completely.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]201
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]202<p><a href="TestingGuide.html#quicktestsuite">LLVM test suite</a> provides a
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]203 framework to test optimizer's handling of debugging information. It can be
204 run like this:</p>
Devang Patela5c05aa2008-11-21 19:35:57 +0000[diff] [blame]205
206<div class="doc_code">
207<pre>
208% cd llvm/projects/test-suite/MultiSource/Benchmarks # or some other level
209% make TEST=dbgopt
210</pre>
211</div>
212
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]213<p>This will test impact of debugging information on optimization passes. If
214 debugging information influences optimization passes then it will be reported
215 as a failure. See <a href="TestingGuide.html">TestingGuide</a> for more
216 information on LLVM test infrastructure and how to run various tests.</p>
Devang Patela5c05aa2008-11-21 19:35:57 +0000[diff] [blame]217
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]218</div>
219
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]220</div>
221
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]222<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]223<h2>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]224 <a name="format">Debugging information format</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]225</h2>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]226<!-- *********************************************************************** -->
227
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]228<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]229
230<p>LLVM debugging information has been carefully designed to make it possible
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]231 for the optimizer to optimize the program and debugging information without
232 necessarily having to know anything about debugging information. In
John Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]233 particular, the use of metadata avoids duplicated debugging information from
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]234 the beginning, and the global dead code elimination pass automatically
235 deletes debugging information for a function if it decides to delete the
236 function. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]237
238<p>To do this, most of the debugging information (descriptors for types,
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]239 variables, functions, source files, etc) is inserted by the language
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]240 front-end in the form of LLVM metadata. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]241
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]242<p>Debug information is designed to be agnostic about the target debugger and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]243 debugging information representation (e.g. DWARF/Stabs/etc). It uses a
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]244 generic pass to decode the information that represents variables, types,
245 functions, namespaces, etc: this allows for arbitrary source-language
246 semantics and type-systems to be used, as long as there is a module
247 written for the target debugger to interpret the information. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]248
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]249<p>To provide basic functionality, the LLVM debugger does have to make some
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]250 assumptions about the source-level language being debugged, though it keeps
251 these to a minimum. The only common features that the LLVM debugger assumes
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]252 exist are <a href="#format_files">source files</a>,
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]253 and <a href="#format_global_variables">program objects</a>. These abstract
254 objects are used by a debugger to form stack traces, show information about
255 local variables, etc.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]256
257<p>This section of the documentation first describes the representation aspects
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]258 common to any source-language. The <a href="#ccxx_frontend">next section</a>
259 describes the data layout conventions used by the C and C++ front-ends.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]260
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]261<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]262<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]263 <a name="debug_info_descriptors">Debug information descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]264</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]265
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]266<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]267
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]268<p>In consideration of the complexity and volume of debug information, LLVM
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]269 provides a specification for well formed debug descriptors. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]270
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]271<p>Consumers of LLVM debug information expect the descriptors for program
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]272 objects to start in a canonical format, but the descriptors can include
273 additional information appended at the end that is source-language
274 specific. All LLVM debugging information is versioned, allowing backwards
275 compatibility in the case that the core structures need to change in some
276 way. Also, all debugging information objects start with a tag to indicate
277 what type of object it is. The source-language is allowed to define its own
278 objects, by using unreserved tag numbers. We recommend using with tags in
Benjamin Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]279 the range 0x1000 through 0x2000 (there is a defined enum DW_TAG_user_base =
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]280 0x1000.)</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]281
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]282<p>The fields of debug descriptors used internally by LLVM
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]283 are restricted to only the simple data types <tt>i32</tt>, <tt>i1</tt>,
284 <tt>float</tt>, <tt>double</tt>, <tt>mdstring</tt> and <tt>mdnode</tt>. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]285
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]286<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]287<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]288!1 = metadata !{
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]289 i32, ;; A tag
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]290 ...
291}
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]292</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]293</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]294
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]295<p><a name="LLVMDebugVersion">The first field of a descriptor is always an
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]296 <tt>i32</tt> containing a tag value identifying the content of the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]297 descriptor. The remaining fields are specific to the descriptor. The values
298 of tags are loosely bound to the tag values of DWARF information entries.
299 However, that does not restrict the use of the information supplied to DWARF
300 targets. To facilitate versioning of debug information, the tag is augmented
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]301 with the current debug version (LLVMDebugVersion = 8 &lt;&lt; 16 or 0x80000 or
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]302 524288.)</a></p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]303
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]304<p>The details of the various descriptors follow.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]305
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]306<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]307<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]308 <a name="format_compile_units">Compile unit descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]309</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]310
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]311<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]312
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]313<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]314<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]315!0 = metadata !{
316 i32, ;; Tag = 17 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
317 ;; (DW_TAG_compile_unit)
318 i32, ;; Unused field.
319 i32, ;; DWARF language identifier (ex. DW_LANG_C89)
320 metadata, ;; Source file name
321 metadata, ;; Source file directory (includes trailing slash)
322 metadata ;; Producer (ex. "4.0.1 LLVM (LLVM research group)")
323 i1, ;; True if this is a main compile unit.
324 i1, ;; True if this is optimized.
325 metadata, ;; Flags
326 i32 ;; Runtime version
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]327}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]328</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]329</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]330
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]331<p>These descriptors contain a source language ID for the file (we use the DWARF
332 3.0 ID numbers, such as <tt>DW_LANG_C89</tt>, <tt>DW_LANG_C_plus_plus</tt>,
333 <tt>DW_LANG_Cobol74</tt>, etc), three strings describing the filename,
334 working directory of the compiler, and an identifier string for the compiler
335 that produced it.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]336
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]337<p>Compile unit descriptors provide the root context for objects declared in a
Devang Patel464f4ef2011-05-03 16:18:28 +0000[diff] [blame]338 specific compilation unit. File descriptors are defined using this context.
339 These descriptors are collected by a named metadata
340 <tt>!llvm.dbg.cu</tt>.
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]341
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]342</div>
343
344<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]345<h4>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]346 <a name="format_files">File descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]347</h4>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]348
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]349<div>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]350
351<div class="doc_code">
352<pre>
353!0 = metadata !{
354 i32, ;; Tag = 41 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
355 ;; (DW_TAG_file_type)
356 metadata, ;; Source file name
357 metadata, ;; Source file directory (includes trailing slash)
358 metadata ;; Reference to compile unit where defined
359}
360</pre>
361</div>
362
John Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]363<p>These descriptors contain information for a file. Global variables and top
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]364 level functions would be defined using this context.k File descriptors also
365 provide context for source line correspondence. </p>
366
367<p>Each input file is encoded as a separate file descriptor in LLVM debugging
368 information output. Each file descriptor would be defined using a
369 compile unit. </p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]370
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]371</div>
372
373<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]374<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]375 <a name="format_global_variables">Global variable descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]376</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]377
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]378<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]379
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]380<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]381<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]382!1 = metadata !{
383 i32, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
384 ;; (DW_TAG_variable)
385 i32, ;; Unused field.
386 metadata, ;; Reference to context descriptor
387 metadata, ;; Name
388 metadata, ;; Display name (fully qualified C++ name)
389 metadata, ;; MIPS linkage name (for C++)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]390 metadata, ;; Reference to file where defined
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]391 i32, ;; Line number where defined
392 metadata, ;; Reference to type descriptor
393 i1, ;; True if the global is local to compile unit (static)
394 i1, ;; True if the global is defined in the compile unit (not extern)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]395 {}* ;; Reference to the global variable
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]396}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]397</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]398</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]399
400<p>These descriptors provide debug information about globals variables. The
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]401provide details such as name, type and where the variable is defined. All
402global variables are collected by named metadata <tt>!llvm.dbg.gv</tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]403
404</div>
405
406<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]407<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]408 <a name="format_subprograms">Subprogram descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]409</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]410
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]411<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]412
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]413<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]414<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]415!2 = metadata !{
416 i32, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
417 ;; (DW_TAG_subprogram)
418 i32, ;; Unused field.
419 metadata, ;; Reference to context descriptor
420 metadata, ;; Name
421 metadata, ;; Display name (fully qualified C++ name)
422 metadata, ;; MIPS linkage name (for C++)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]423 metadata, ;; Reference to file where defined
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]424 i32, ;; Line number where defined
425 metadata, ;; Reference to type descriptor
426 i1, ;; True if the global is local to compile unit (static)
Devang Patel5e06bb82011-04-22 23:10:17 +0000[diff] [blame]427 i1, ;; True if the global is defined in the compile unit (not extern)
428 i32, ;; Virtuality, e.g. dwarf::DW_VIRTUALITY__virtual
429 i32, ;; Index into a virtual function
Devang Patel80ecc152010-06-04 22:49:55 +0000[diff] [blame]430 metadata, ;; indicates which base type contains the vtable pointer for the
431 ;; derived class
Devang Patel5e06bb82011-04-22 23:10:17 +0000[diff] [blame]432 i1, ;; isArtificial
433 i1, ;; isOptimized
434 Function *,;; Pointer to LLVM function
435 metadata, ;; Lists function template parameters
436 metadata ;; Function declaration descriptor
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]437}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]438</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]439</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]440
441<p>These descriptors provide debug information about functions, methods and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]442 subprograms. They provide details such as name, return types and the source
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]443 location where the subprogram is defined.
444 All subprogram descriptors are collected by a named metadata
445 <tt>!llvm.dbg.sp</tt>.
446</p>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]447
448</div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]449
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]450<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]451<h4>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]452 <a name="format_blocks">Block descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]453</h4>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]454
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]455<div>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]456
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]457<div class="doc_code">
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]458<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]459!3 = metadata !{
Devang Patelc79dda22010-10-04 16:51:59 +0000[diff] [blame]460 i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
Devang Patel7f271fc2010-10-01 22:45:00 +0000[diff] [blame]461 metadata,;; Reference to context descriptor
462 i32, ;; Line number
Devang Patel90d81f12011-03-08 16:25:29 +0000[diff] [blame]463 i32, ;; Column number
464 metadata,;; Reference to source file
465 i32 ;; Unique ID to identify blocks from a template function
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]466}
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]467</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]468</div>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]469
470<p>These descriptors provide debug information about nested blocks within a
Devang Patel7f271fc2010-10-01 22:45:00 +0000[diff] [blame]471 subprogram. The line number and column numbers are used to dinstinguish
472 two lexical blocks at same depth. </p>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]473
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]474</div>
475
476<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]477<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]478 <a name="format_basic_type">Basic type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]479</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]480
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]481<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]482
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]483<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]484<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]485!4 = metadata !{
486 i32, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
487 ;; (DW_TAG_base_type)
488 metadata, ;; Reference to context (typically a compile unit)
489 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]490 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]491 i32, ;; Line number where defined (may be 0)
492 i64, ;; Size in bits
493 i64, ;; Alignment in bits
494 i64, ;; Offset in bits
495 i32, ;; Flags
496 i32 ;; DWARF type encoding
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]497}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]498</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]499</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]500
501<p>These descriptors define primitive types used in the code. Example int, bool
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]502 and float. The context provides the scope of the type, which is usually the
503 top level. Since basic types are not usually user defined the compile unit
504 and line number can be left as NULL and 0. The size, alignment and offset
505 are expressed in bits and can be 64 bit values. The alignment is used to
506 round the offset when embedded in a
507 <a href="#format_composite_type">composite type</a> (example to keep float
508 doubles on 64 bit boundaries.) The offset is the bit offset if embedded in
509 a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]510
511<p>The type encoding provides the details of the type. The values are typically
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]512 one of the following:</p>
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>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]516DW_ATE_address = 1
517DW_ATE_boolean = 2
518DW_ATE_float = 4
519DW_ATE_signed = 5
520DW_ATE_signed_char = 6
521DW_ATE_unsigned = 7
522DW_ATE_unsigned_char = 8
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]523</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]524</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]525
526</div>
527
528<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]529<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]530 <a name="format_derived_type">Derived type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]531</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]532
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]533<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]534
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]535<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]536<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]537!5 = metadata !{
538 i32, ;; Tag (see below)
539 metadata, ;; Reference to context
540 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]541 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]542 i32, ;; Line number where defined (may be 0)
Devang Patel0ffd10b2010-10-01 19:19:30 +0000[diff] [blame]543 i64, ;; Size in bits
544 i64, ;; Alignment in bits
545 i64, ;; Offset in bits
Devang Patele9db5e22011-04-16 00:11:51 +0000[diff] [blame]546 metadata, ;; Reference to type derived from
547 metadata, ;; (optional) Name of the Objective C property assoicated with
548 ;; Objective-C an ivar
549 metadata, ;; (optional) Name of the Objective C property getter selector.
550 metadata, ;; (optional) Name of the Objective C property setter selector.
551 i32 ;; (optional) Objective C property attributes.
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]552}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]553</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]554</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]555
556<p>These descriptors are used to define types derived from other types. The
557value of the tag varies depending on the meaning. The following are possible
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]558tag values:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]559
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]560<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]561<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]562DW_TAG_formal_parameter = 5
563DW_TAG_member = 13
564DW_TAG_pointer_type = 15
565DW_TAG_reference_type = 16
566DW_TAG_typedef = 22
567DW_TAG_const_type = 38
568DW_TAG_volatile_type = 53
569DW_TAG_restrict_type = 55
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]570</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]571</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]572
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]573<p><tt>DW_TAG_member</tt> is used to define a member of
574 a <a href="#format_composite_type">composite type</a>
575 or <a href="#format_subprograms">subprogram</a>. The type of the member is
576 the <a href="#format_derived_type">derived
577 type</a>. <tt>DW_TAG_formal_parameter</tt> is used to define a member which
578 is a formal argument of a subprogram.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]579
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]580<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]581
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]582<p><tt>DW_TAG_pointer_type</tt>,<tt>DW_TAG_reference_type</tt>,
583 <tt>DW_TAG_const_type</tt>, <tt>DW_TAG_volatile_type</tt>
584 and <tt>DW_TAG_restrict_type</tt> are used to qualify
585 the <a href="#format_derived_type">derived type</a>. </p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]586
587<p><a href="#format_derived_type">Derived type</a> location can be determined
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]588 from the compile unit and line number. The size, alignment and offset are
589 expressed in bits and can be 64 bit values. The alignment is used to round
590 the offset when embedded in a <a href="#format_composite_type">composite
591 type</a> (example to keep float doubles on 64 bit boundaries.) The offset is
592 the bit offset if embedded in a <a href="#format_composite_type">composite
593 type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]594
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]595<p>Note that the <tt>void *</tt> type is expressed as a type derived from NULL.
596</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]597
598</div>
599
600<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]601<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]602 <a name="format_composite_type">Composite type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]603</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]604
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]605<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]606
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]607<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]608<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]609!6 = metadata !{
610 i32, ;; Tag (see below)
611 metadata, ;; Reference to context
612 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]613 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]614 i32, ;; Line number where defined (may be 0)
615 i64, ;; Size in bits
616 i64, ;; Alignment in bits
617 i64, ;; Offset in bits
618 i32, ;; Flags
619 metadata, ;; Reference to type derived from
620 metadata, ;; Reference to array of member descriptors
621 i32 ;; Runtime languages
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]622}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]623</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]624</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]625
626<p>These descriptors are used to define types that are composed of 0 or more
627elements. The value of the tag varies depending on the meaning. The following
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]628are possible tag values:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]629
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]630<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]631<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]632DW_TAG_array_type = 1
633DW_TAG_enumeration_type = 4
634DW_TAG_structure_type = 19
635DW_TAG_union_type = 23
636DW_TAG_vector_type = 259
Bruno Cardoso Lopesd80ddc02009-05-29 17:08:57 +0000[diff] [blame]637DW_TAG_subroutine_type = 21
638DW_TAG_inheritance = 28
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]639</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]640</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]641
Jim Laskeyf8a01a92006-06-15 20:51:43 +0000[diff] [blame]642<p>The vector flag indicates that an array type is a native packed vector.</p>
643
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]644<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]645 (tag = <tt>DW_TAG_vector_type</tt>) are <a href="#format_subrange">subrange
646 descriptors</a>, each representing the range of subscripts at that level of
647 indexing.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]648
649<p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]650 <a href="#format_enumeration">enumerator descriptors</a>, each representing
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]651 the definition of enumeration value for the set. All enumeration type
652 descriptors are collected by named metadata <tt>!llvm.dbg.enum</tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]653
654<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]655 = <tt>DW_TAG_union_type</tt>) types are any one of
656 the <a href="#format_basic_type">basic</a>,
657 <a href="#format_derived_type">derived</a>
658 or <a href="#format_composite_type">composite</a> type descriptors, each
659 representing a field member of the structure or union.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]660
Jim Laskey4a9df242006-08-21 21:21:06 +0000[diff] [blame]661<p>For C++ classes (tag = <tt>DW_TAG_structure_type</tt>), member descriptors
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]662 provide information about base classes, static members and member
663 functions. If a member is a <a href="#format_derived_type">derived type
664 descriptor</a> and has a tag of <tt>DW_TAG_inheritance</tt>, then the type
665 represents a base class. If the member of is
666 a <a href="#format_global_variables">global variable descriptor</a> then it
667 represents a static member. And, if the member is
668 a <a href="#format_subprograms">subprogram descriptor</a> then it represents
669 a member function. For static members and member
670 functions, <tt>getName()</tt> returns the members link or the C++ mangled
671 name. <tt>getDisplayName()</tt> the simplied version of the name.</p>
Jim Laskey4a9df242006-08-21 21:21:06 +0000[diff] [blame]672
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]673<p>The first member of subroutine (tag = <tt>DW_TAG_subroutine_type</tt>) type
674 elements is the return type for the subroutine. The remaining elements are
675 the formal arguments to the subroutine.</p>
Jim Laskey094ee722006-06-20 21:13:20 +0000[diff] [blame]676
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]677<p><a href="#format_composite_type">Composite type</a> location can be
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]678 determined from the compile unit and line number. The size, alignment and
679 offset are expressed in bits and can be 64 bit values. The alignment is used
680 to round the offset when embedded in
681 a <a href="#format_composite_type">composite type</a> (as an example, to keep
682 float doubles on 64 bit boundaries.) The offset is the bit offset if embedded
683 in a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]684
685</div>
686
687<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]688<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]689 <a name="format_subrange">Subrange descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]690</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]691
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]692<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]693
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]694<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]695<pre>
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]696!42 = metadata !{
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]697 i32, ;; Tag = 33 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subrange_type)
698 i64, ;; Low value
699 i64 ;; High value
700}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]701</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]702</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]703
704<p>These descriptors are used to define ranges of array subscripts for an array
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]705 <a href="#format_composite_type">composite type</a>. The low value defines
706 the lower bounds typically zero for C/C++. The high value is the upper
707 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]708 > high the array bounds are not included in generated debugging information.
709</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]710
711</div>
712
713<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]714<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]715 <a name="format_enumeration">Enumerator descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]716</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]717
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]718<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]719
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]720<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]721<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]722!6 = metadata !{
723 i32, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
724 ;; (DW_TAG_enumerator)
725 metadata, ;; Name
726 i64 ;; Value
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]727}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]728</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]729</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]730
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]731<p>These descriptors are used to define members of an
732 enumeration <a href="#format_composite_type">composite type</a>, it
733 associates the name to the value.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]734
735</div>
736
737<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]738<h4>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]739 <a name="format_variables">Local variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]740</h4>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]741
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]742<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]743
744<div class="doc_code">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]745<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]746!7 = metadata !{
747 i32, ;; Tag (see below)
748 metadata, ;; Context
749 metadata, ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]750 metadata, ;; Reference to file where defined
Devang Patela83688f2011-03-08 16:29:40 +0000[diff] [blame]751 i32, ;; 24 bit - Line number where defined
752 ;; 8 bit - Argument number. 1 indicates 1st argument.
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]753 metadata ;; Type descriptor
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]754}
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]755</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]756</div>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]757
758<p>These descriptors are used to define variables local to a sub program. The
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]759 value of the tag depends on the usage of the variable:</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]760
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]761<div class="doc_code">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]762<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]763DW_TAG_auto_variable = 256
764DW_TAG_arg_variable = 257
765DW_TAG_return_variable = 258
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]766</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]767</div>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]768
769<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]770 argument variable is any variable that appears as a formal argument to the
771 function. A return variable is used to track the result of a function and
772 has no source correspondent.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]773
Jim Laskey2d395d92006-03-24 09:20:27 +0000[diff] [blame]774<p>The context is either the subprogram or block where the variable is defined.
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]775 Name the source variable name. Compile unit and line indicate where the
776 variable was defined. Type descriptor defines the declared type of the
777 variable.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]778
779</div>
780
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]781</div>
782
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]783<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]784<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]785 <a name="format_common_intrinsics">Debugger intrinsic functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]786</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]787
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]788<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]789
790<p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]791 provide debug information at various points in generated code.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]792
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]793<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]794<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]795 <a name="format_common_declare">llvm.dbg.declare</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]796</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]797
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]798<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]799<pre>
Devang Patel4c7c0c62010-10-01 19:22:16 +0000[diff] [blame]800 void %<a href="#format_common_declare">llvm.dbg.declare</a>(metadata, metadata)
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]801</pre>
802
Jim Laskey2d395d92006-03-24 09:20:27 +0000[diff] [blame]803<p>This intrinsic provides information about a local element (ex. variable.) The
NAKAMURA Takumi4d6deb02011-04-09 09:51:57 +0000[diff] [blame]804 first argument is metadata holding alloca for the variable. The
Devang Patele136e502011-02-01 17:22:12 +0000[diff] [blame]805 second argument is metadata containing description of the variable. </p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]806</div>
807
808<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]809<h4>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]810 <a name="format_common_value">llvm.dbg.value</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]811</h4>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]812
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]813<div>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]814<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]815 void %<a href="#format_common_value">llvm.dbg.value</a>(metadata, i64, metadata)
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]816</pre>
817
818<p>This intrinsic provides information when a user source variable is set to a
819 new value. The first argument is the new value (wrapped as metadata). The
820 second argument is the offset in the user source variable where the new value
Devang Patele136e502011-02-01 17:22:12 +0000[diff] [blame]821 is written. The third argument is metadata containing description of the
822 user source variable. </p>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]823</div>
824
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]825</div>
826
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]827<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]828<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]829 <a name="format_common_lifetime">Object lifetimes and scoping</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]830</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]831
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]832<div>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]833<p>In many languages, the local variables in functions can have their lifetimes
834 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]835 for example, variables are only live (readable and writable) within the
836 source block that they are defined in. In functional languages, values are
837 only readable after they have been defined. Though this is a very obvious
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]838 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]839 scoping in this sense, and does not want to be tied to a language's scoping
840 rules.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]841
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]842<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]843 llvm instructions to encode line number and scoping information. Consider
844 the following C fragment, for example:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]845
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]846<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]847<pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8481. void foo() {
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8492. int X = 21;
8503. int Y = 22;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8514. {
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8525. int Z = 23;
8536. Z = X;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8547. }
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8558. X = Y;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8569. }
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]857</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]858</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]859
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]860<p>Compiled to LLVM, this function would be represented like this:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]861
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]862<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]863<pre>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]864define void @foo() nounwind ssp {
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]865entry:
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]866 %X = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
867 %Y = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
868 %Z = alloca i32, align 4 ; &lt;i32*&gt; [#uses=3]
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]869 %0 = bitcast i32* %X to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]870 call void @llvm.dbg.declare(metadata !{i32 * %X}, metadata !0), !dbg !7
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]871 store i32 21, i32* %X, !dbg !8
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]872 %1 = bitcast i32* %Y to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]873 call void @llvm.dbg.declare(metadata !{i32 * %Y}, metadata !9), !dbg !10
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]874 store i32 22, i32* %Y, !dbg !11
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]875 %2 = bitcast i32* %Z to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]876 call void @llvm.dbg.declare(metadata !{i32 * %Z}, metadata !12), !dbg !14
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]877 store i32 23, i32* %Z, !dbg !15
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]878 %tmp = load i32* %X, !dbg !16 ; &lt;i32&gt; [#uses=1]
879 %tmp1 = load i32* %Y, !dbg !16 ; &lt;i32&gt; [#uses=1]
880 %add = add nsw i32 %tmp, %tmp1, !dbg !16 ; &lt;i32&gt; [#uses=1]
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]881 store i32 %add, i32* %Z, !dbg !16
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]882 %tmp2 = load i32* %Y, !dbg !17 ; &lt;i32&gt; [#uses=1]
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]883 store i32 %tmp2, i32* %X, !dbg !17
884 ret void, !dbg !18
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]885}
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]886
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]887declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]888
889!0 = metadata !{i32 459008, metadata !1, metadata !"X",
890 metadata !3, i32 2, metadata !6}; [ DW_TAG_auto_variable ]
891!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
892!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo", metadata !"foo",
893 metadata !"foo", metadata !3, i32 1, metadata !4,
894 i1 false, i1 true}; [DW_TAG_subprogram ]
895!3 = metadata !{i32 458769, i32 0, i32 12, metadata !"foo.c",
896 metadata !"/private/tmp", metadata !"clang 1.1", i1 true,
897 i1 false, metadata !"", i32 0}; [DW_TAG_compile_unit ]
898!4 = metadata !{i32 458773, metadata !3, metadata !"", null, i32 0, i64 0, i64 0,
899 i64 0, i32 0, null, metadata !5, i32 0}; [DW_TAG_subroutine_type ]
900!5 = metadata !{null}
901!6 = metadata !{i32 458788, metadata !3, metadata !"int", metadata !3, i32 0,
902 i64 32, i64 32, i64 0, i32 0, i32 5}; [DW_TAG_base_type ]
903!7 = metadata !{i32 2, i32 7, metadata !1, null}
904!8 = metadata !{i32 2, i32 3, metadata !1, null}
905!9 = metadata !{i32 459008, metadata !1, metadata !"Y", metadata !3, i32 3,
906 metadata !6}; [ DW_TAG_auto_variable ]
907!10 = metadata !{i32 3, i32 7, metadata !1, null}
908!11 = metadata !{i32 3, i32 3, metadata !1, null}
909!12 = metadata !{i32 459008, metadata !13, metadata !"Z", metadata !3, i32 5,
910 metadata !6}; [ DW_TAG_auto_variable ]
911!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
912!14 = metadata !{i32 5, i32 9, metadata !13, null}
913!15 = metadata !{i32 5, i32 5, metadata !13, null}
914!16 = metadata !{i32 6, i32 5, metadata !13, null}
915!17 = metadata !{i32 8, i32 3, metadata !1, null}
916!18 = metadata !{i32 9, i32 1, metadata !2, null}
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]917</pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]918</div>
919
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]920<p>This example illustrates a few important details about LLVM debugging
921 information. In particular, it shows how the <tt>llvm.dbg.declare</tt>
922 intrinsic and location information, which are attached to an instruction,
923 are applied together to allow a debugger to analyze the relationship between
924 statements, variable definitions, and the code used to implement the
925 function.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]926
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]927<div class="doc_code">
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]928<pre>
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]929call void @llvm.dbg.declare(metadata, metadata !0), !dbg !7
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]930</pre>
931</div>
932
933<p>The first intrinsic
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]934 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]935 encodes debugging information for the variable <tt>X</tt>. The metadata
936 <tt>!dbg !7</tt> attached to the intrinsic provides scope information for the
937 variable <tt>X</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]938
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]939<div class="doc_code">
940<pre>
941!7 = metadata !{i32 2, i32 7, metadata !1, null}
942!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
943!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo",
944 metadata !"foo", metadata !"foo", metadata !3, i32 1,
945 metadata !4, i1 false, i1 true}; [DW_TAG_subprogram ]
946</pre>
947</div>
948
949<p>Here <tt>!7</tt> is metadata providing location information. It has four
950 fields: line number, column number, scope, and original scope. The original
951 scope represents inline location if this instruction is inlined inside a
952 caller, and is null otherwise. In this example, scope is encoded by
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]953 <tt>!1</tt>. <tt>!1</tt> represents a lexical block inside the scope
954 <tt>!2</tt>, where <tt>!2</tt> is a
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]955 <a href="#format_subprograms">subprogram descriptor</a>. This way the
956 location information attached to the intrinsics indicates that the
957 variable <tt>X</tt> is declared at line number 2 at a function level scope in
958 function <tt>foo</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]959
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]960<p>Now lets take another example.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]961
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]962<div class="doc_code">
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]963<pre>
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]964call void @llvm.dbg.declare(metadata, metadata !12), !dbg !14
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]965</pre>
966</div>
967
968<p>The second intrinsic
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]969 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]970 encodes debugging information for variable <tt>Z</tt>. The metadata
971 <tt>!dbg !14</tt> attached to the intrinsic provides scope information for
972 the variable <tt>Z</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]973
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]974<div class="doc_code">
975<pre>
976!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
977!14 = metadata !{i32 5, i32 9, metadata !13, null}
978</pre>
979</div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]980
John Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]981<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]982 column number 9 inside of lexical scope <tt>!13</tt>. The lexical scope
983 itself resides inside of lexical scope <tt>!1</tt> described above.</p>
984
985<p>The scope information attached with each instruction provides a
986 straightforward way to find instructions covered by a scope.</p>
987
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]988</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]989
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]990</div>
991
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]992<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]993<h2>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]994 <a name="ccxx_frontend">C/C++ front-end specific debug information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]995</h2>
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]996<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]997
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]998<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]999
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1000<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]1001 that is effectively identical
1002 to <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3.0</a> in
1003 terms of information content. This allows code generators to trivially
1004 support native debuggers by generating standard dwarf information, and
1005 contains enough information for non-dwarf targets to translate it as
1006 needed.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1007
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1008<p>This section describes the forms used to represent C and C++ programs. Other
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1009 languages could pattern themselves after this (which itself is tuned to
1010 representing programs in the same way that DWARF 3 does), or they could
1011 choose to provide completely different forms if they don't fit into the DWARF
1012 model. As support for debugging information gets added to the various LLVM
1013 source-language front-ends, the information used should be documented
1014 here.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1015
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1016<p>The following sections provide examples of various C/C++ constructs and the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1017 debug information that would best describe those constructs.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1018
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1019<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1020<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1021 <a name="ccxx_compile_units">C/C++ source file information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1022</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1023
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1024<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1025
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1026<p>Given the source files <tt>MySource.cpp</tt> and <tt>MyHeader.h</tt> located
1027 in the directory <tt>/Users/mine/sources</tt>, the following code:</p>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1028
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1029<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1030<pre>
1031#include "MyHeader.h"
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1032
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1033int main(int argc, char *argv[]) {
1034 return 0;
1035}
1036</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1037</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1038
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1039<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1040
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1041<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1042<pre>
1043...
1044;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1045;; Define the compile unit for the main source file "/Users/mine/sources/MySource.cpp".
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1046;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1047!2 = metadata !{
1048 i32 524305, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1049 i32 0, ;; Unused
1050 i32 4, ;; Language Id
1051 metadata !"MySource.cpp",
1052 metadata !"/Users/mine/sources",
1053 metadata !"4.2.1 (Based on Apple Inc. build 5649) (LLVM build 00)",
1054 i1 true, ;; Main Compile Unit
1055 i1 false, ;; Optimized compile unit
1056 metadata !"", ;; Compiler flags
1057 i32 0} ;; Runtime version
1058
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1059;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1060;; Define the file for the file "/Users/mine/sources/MySource.cpp".
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1061;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1062!1 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1063 i32 524329, ;; Tag
1064 metadata !"MySource.cpp",
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1065 metadata !"/Users/mine/sources",
Devang Patel9fea9c22010-07-13 16:53:20 +0000[diff] [blame]1066 metadata !2 ;; Compile unit
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1067}
1068
1069;;
1070;; Define the file for the file "/Users/mine/sources/Myheader.h"
1071;;
1072!3 = metadata !{
1073 i32 524329, ;; Tag
1074 metadata !"Myheader.h"
1075 metadata !"/Users/mine/sources",
Devang Patel9fea9c22010-07-13 16:53:20 +0000[diff] [blame]1076 metadata !2 ;; Compile unit
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1077}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1078
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1079...
1080</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1081</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1082
Devang Pateld98ec5f2010-03-26 19:08:36 +0000[diff] [blame]1083<p>llvm::Instruction provides easy access to metadata attached with an
1084instruction. One can extract line number information encoded in LLVM IR
1085using <tt>Instruction::getMetadata()</tt> and
1086<tt>DILocation::getLineNumber()</tt>.
1087<pre>
1088 if (MDNode *N = I->getMetadata("dbg")) { // Here I is an LLVM instruction
1089 DILocation Loc(N); // DILocation is in DebugInfo.h
1090 unsigned Line = Loc.getLineNumber();
1091 StringRef File = Loc.getFilename();
1092 StringRef Dir = Loc.getDirectory();
1093 }
1094</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1095</div>
1096
1097<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1098<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1099 <a name="ccxx_global_variable">C/C++ global variable information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1100</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1101
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1102<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1103
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1104<p>Given an integer global variable declared as follows:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1105
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1106<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1107<pre>
1108int MyGlobal = 100;
1109</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1110</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1111
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1112<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1113
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1114<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1115<pre>
1116;;
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1117;; Define the global itself.
1118;;
1119%MyGlobal = global int 100
1120...
1121;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1122;; List of debug info of globals
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1123;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1124!llvm.dbg.gv = !{!0}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1125
1126;;
1127;; Define the global variable descriptor. Note the reference to the global
1128;; variable anchor and the global variable itself.
1129;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1130!0 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1131 i32 524340, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1132 i32 0, ;; Unused
1133 metadata !1, ;; Context
1134 metadata !"MyGlobal", ;; Name
1135 metadata !"MyGlobal", ;; Display Name
1136 metadata !"MyGlobal", ;; Linkage Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1137 metadata !3, ;; Compile Unit
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1138 i32 1, ;; Line Number
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1139 metadata !4, ;; Type
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1140 i1 false, ;; Is a local variable
1141 i1 true, ;; Is this a definition
1142 i32* @MyGlobal ;; The global variable
1143}
1144
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1145;;
1146;; Define the basic type of 32 bit signed integer. Note that since int is an
1147;; intrinsic type the source file is NULL and line 0.
1148;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1149!4 = metadata !{
1150 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1151 metadata !1, ;; Context
1152 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1153 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1154 i32 0, ;; Line number
1155 i64 32, ;; Size in Bits
1156 i64 32, ;; Align in Bits
1157 i64 0, ;; Offset in Bits
1158 i32 0, ;; Flags
1159 i32 5 ;; Encoding
1160}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1161
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1162</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1163</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1164
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1165</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1166
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1167<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1168<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1169 <a name="ccxx_subprogram">C/C++ function information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1170</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1171
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1172<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1173
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1174<p>Given a function declared as follows:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1175
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1176<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1177<pre>
1178int main(int argc, char *argv[]) {
1179 return 0;
1180}
1181</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1182</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1183
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1184<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1185
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1186<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1187<pre>
1188;;
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1189;; Define the anchor for subprograms. Note that the second field of the
1190;; anchor is 46, which is the same as the tag for subprograms
1191;; (46 = DW_TAG_subprogram.)
1192;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1193!6 = metadata !{
1194 i32 524334, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1195 i32 0, ;; Unused
1196 metadata !1, ;; Context
1197 metadata !"main", ;; Name
1198 metadata !"main", ;; Display name
1199 metadata !"main", ;; Linkage name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1200 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1201 i32 1, ;; Line number
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1202 metadata !4, ;; Type
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1203 i1 false, ;; Is local
Devang Patelda194752011-04-05 22:52:06 +0000[diff] [blame]1204 i1 true, ;; Is definition
1205 i32 0, ;; Virtuality attribute, e.g. pure virtual function
1206 i32 0, ;; Index into virtual table for C++ methods
1207 i32 0, ;; Type that holds virtual table.
1208 i32 0, ;; Flags
1209 i1 false, ;; True if this function is optimized
1210 Function *, ;; Pointer to llvm::Function
1211 null ;; Function template parameters
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1212}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1213;;
1214;; Define the subprogram itself.
1215;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1216define i32 @main(i32 %argc, i8** %argv) {
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1217...
1218}
1219</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1220</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1221
1222</div>
1223
1224<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1225<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1226 <a name="ccxx_basic_types">C/C++ basic types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1227</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1228
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1229<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1230
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1231<p>The following are the basic type descriptors for C/C++ core types:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1232
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1233<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1234<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1235 <a name="ccxx_basic_type_bool">bool</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1236</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1237
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1238<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1239
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1240<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1241<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1242!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1243 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1244 metadata !1, ;; Context
1245 metadata !"bool", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1246 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1247 i32 0, ;; Line number
1248 i64 8, ;; Size in Bits
1249 i64 8, ;; Align in Bits
1250 i64 0, ;; Offset in Bits
1251 i32 0, ;; Flags
1252 i32 2 ;; Encoding
1253}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1254</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1255</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1256
1257</div>
1258
1259<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1260<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1261 <a name="ccxx_basic_char">char</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1262</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1263
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1264<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1265
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1266<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1267<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1268!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1269 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1270 metadata !1, ;; Context
1271 metadata !"char", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1272 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1273 i32 0, ;; Line number
1274 i64 8, ;; Size in Bits
1275 i64 8, ;; Align in Bits
1276 i64 0, ;; Offset in Bits
1277 i32 0, ;; Flags
1278 i32 6 ;; Encoding
1279}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1280</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1281</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1282
1283</div>
1284
1285<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1286<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1287 <a name="ccxx_basic_unsigned_char">unsigned char</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1288</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1289
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1290<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1291
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1292<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1293<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1294!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1295 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1296 metadata !1, ;; Context
1297 metadata !"unsigned char",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1298 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1299 i32 0, ;; Line number
1300 i64 8, ;; Size in Bits
1301 i64 8, ;; Align in Bits
1302 i64 0, ;; Offset in Bits
1303 i32 0, ;; Flags
1304 i32 8 ;; Encoding
1305}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1306</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1307</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1308
1309</div>
1310
1311<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1312<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1313 <a name="ccxx_basic_short">short</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1314</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1315
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1316<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1317
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1318<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1319<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1320!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1321 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1322 metadata !1, ;; Context
1323 metadata !"short int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1324 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1325 i32 0, ;; Line number
1326 i64 16, ;; Size in Bits
1327 i64 16, ;; Align in Bits
1328 i64 0, ;; Offset in Bits
1329 i32 0, ;; Flags
1330 i32 5 ;; Encoding
1331}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1332</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1333</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1334
1335</div>
1336
1337<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1338<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1339 <a name="ccxx_basic_unsigned_short">unsigned short</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1340</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1341
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1342<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1343
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1344<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1345<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1346!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1347 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1348 metadata !1, ;; Context
1349 metadata !"short unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1350 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1351 i32 0, ;; Line number
1352 i64 16, ;; Size in Bits
1353 i64 16, ;; Align in Bits
1354 i64 0, ;; Offset in Bits
1355 i32 0, ;; Flags
1356 i32 7 ;; Encoding
1357}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1358</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1359</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1360
1361</div>
1362
1363<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1364<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1365 <a name="ccxx_basic_int">int</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1366</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1367
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1368<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1369
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1370<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1371<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1372!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1373 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1374 metadata !1, ;; Context
1375 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1376 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1377 i32 0, ;; Line number
1378 i64 32, ;; Size in Bits
1379 i64 32, ;; Align in Bits
1380 i64 0, ;; Offset in Bits
1381 i32 0, ;; Flags
1382 i32 5 ;; Encoding
1383}
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1384</pre></div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1385
1386</div>
1387
1388<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1389<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1390 <a name="ccxx_basic_unsigned_int">unsigned int</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1391</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1392
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1393<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1394
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1395<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1396<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1397!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1398 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1399 metadata !1, ;; Context
1400 metadata !"unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1401 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1402 i32 0, ;; Line number
1403 i64 32, ;; Size in Bits
1404 i64 32, ;; Align in Bits
1405 i64 0, ;; Offset in Bits
1406 i32 0, ;; Flags
1407 i32 7 ;; Encoding
1408}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1409</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1410</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1411
1412</div>
1413
1414<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1415<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1416 <a name="ccxx_basic_long_long">long long</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1417</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1418
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1419<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1420
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1421<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1422<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1423!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1424 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1425 metadata !1, ;; Context
1426 metadata !"long long int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1427 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1428 i32 0, ;; Line number
1429 i64 64, ;; Size in Bits
1430 i64 64, ;; Align in Bits
1431 i64 0, ;; Offset in Bits
1432 i32 0, ;; Flags
1433 i32 5 ;; Encoding
1434}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1435</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1436</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1437
1438</div>
1439
1440<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1441<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1442 <a name="ccxx_basic_unsigned_long_long">unsigned long long</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1443</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1444
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1445<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1446
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1447<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1448<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1449!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1450 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1451 metadata !1, ;; Context
1452 metadata !"long long unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1453 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1454 i32 0, ;; Line number
1455 i64 64, ;; Size in Bits
1456 i64 64, ;; Align in Bits
1457 i64 0, ;; Offset in Bits
1458 i32 0, ;; Flags
1459 i32 7 ;; Encoding
1460}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1461</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1462</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1463
1464</div>
1465
1466<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1467<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1468 <a name="ccxx_basic_float">float</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1469</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1470
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1471<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1472
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1473<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1474<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1475!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1476 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1477 metadata !1, ;; Context
1478 metadata !"float",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1479 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1480 i32 0, ;; Line number
1481 i64 32, ;; Size in Bits
1482 i64 32, ;; Align in Bits
1483 i64 0, ;; Offset in Bits
1484 i32 0, ;; Flags
1485 i32 4 ;; Encoding
1486}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1487</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1488</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1489
1490</div>
1491
1492<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1493<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1494 <a name="ccxx_basic_double">double</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1495</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1496
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1497<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1498
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1499<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1500<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1501!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1502 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1503 metadata !1, ;; Context
1504 metadata !"double",;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1505 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1506 i32 0, ;; Line number
1507 i64 64, ;; Size in Bits
1508 i64 64, ;; Align in Bits
1509 i64 0, ;; Offset in Bits
1510 i32 0, ;; Flags
1511 i32 4 ;; Encoding
1512}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1513</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1514</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1515
1516</div>
1517
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1518</div>
1519
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1520<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1521<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1522 <a name="ccxx_derived_types">C/C++ derived types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1523</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1524
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1525<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1526
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1527<p>Given the following as an example of C/C++ derived type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1528
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1529<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1530<pre>
1531typedef const int *IntPtr;
1532</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1533</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1534
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1535<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1536
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1537<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1538<pre>
1539;;
1540;; Define the typedef "IntPtr".
1541;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1542!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1543 i32 524310, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1544 metadata !1, ;; Context
1545 metadata !"IntPtr", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1546 metadata !3, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1547 i32 0, ;; Line number
1548 i64 0, ;; Size in bits
1549 i64 0, ;; Align in bits
1550 i64 0, ;; Offset in bits
1551 i32 0, ;; Flags
1552 metadata !4 ;; Derived From type
1553}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1554
1555;;
1556;; Define the pointer type.
1557;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1558!4 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1559 i32 524303, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1560 metadata !1, ;; Context
1561 metadata !"", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1562 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1563 i32 0, ;; Line number
1564 i64 64, ;; Size in bits
1565 i64 64, ;; Align in bits
1566 i64 0, ;; Offset in bits
1567 i32 0, ;; Flags
1568 metadata !5 ;; Derived From type
1569}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1570;;
1571;; Define the const type.
1572;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1573!5 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1574 i32 524326, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1575 metadata !1, ;; Context
1576 metadata !"", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1577 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1578 i32 0, ;; Line number
1579 i64 32, ;; Size in bits
1580 i64 32, ;; Align in bits
1581 i64 0, ;; Offset in bits
1582 i32 0, ;; Flags
1583 metadata !6 ;; Derived From type
1584}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1585;;
1586;; Define the int type.
1587;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1588!6 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1589 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1590 metadata !1, ;; Context
1591 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1592 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1593 i32 0, ;; Line number
1594 i64 32, ;; Size in bits
1595 i64 32, ;; Align in bits
1596 i64 0, ;; Offset in bits
1597 i32 0, ;; Flags
1598 5 ;; Encoding
1599}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1600</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1601</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1602
1603</div>
1604
1605<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1606<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1607 <a name="ccxx_composite_types">C/C++ struct/union types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1608</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1609
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1610<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1611
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1612<p>Given the following as an example of C/C++ struct type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1613
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1614<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1615<pre>
1616struct Color {
1617 unsigned Red;
1618 unsigned Green;
1619 unsigned Blue;
1620};
1621</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1622</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1623
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1624<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1625
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1626<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1627<pre>
1628;;
1629;; Define basic type for unsigned int.
1630;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1631!5 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1632 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1633 metadata !1, ;; Context
1634 metadata !"unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1635 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1636 i32 0, ;; Line number
1637 i64 32, ;; Size in Bits
1638 i64 32, ;; Align in Bits
1639 i64 0, ;; Offset in Bits
1640 i32 0, ;; Flags
1641 i32 7 ;; Encoding
1642}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1643;;
1644;; Define composite type for struct Color.
1645;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1646!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1647 i32 524307, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1648 metadata !1, ;; Context
1649 metadata !"Color", ;; Name
1650 metadata !1, ;; Compile unit
1651 i32 1, ;; Line number
1652 i64 96, ;; Size in bits
1653 i64 32, ;; Align in bits
1654 i64 0, ;; Offset in bits
1655 i32 0, ;; Flags
1656 null, ;; Derived From
1657 metadata !3, ;; Elements
1658 i32 0 ;; Runtime Language
1659}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1660
1661;;
1662;; Define the Red field.
1663;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1664!4 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1665 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1666 metadata !1, ;; Context
1667 metadata !"Red", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1668 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1669 i32 2, ;; Line number
1670 i64 32, ;; Size in bits
1671 i64 32, ;; Align in bits
1672 i64 0, ;; Offset in bits
1673 i32 0, ;; Flags
1674 metadata !5 ;; Derived From type
1675}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1676
1677;;
1678;; Define the Green field.
1679;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1680!6 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1681 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1682 metadata !1, ;; Context
1683 metadata !"Green", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1684 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1685 i32 3, ;; Line number
1686 i64 32, ;; Size in bits
1687 i64 32, ;; Align in bits
1688 i64 32, ;; Offset in bits
1689 i32 0, ;; Flags
1690 metadata !5 ;; Derived From type
1691}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1692
1693;;
1694;; Define the Blue field.
1695;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1696!7 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1697 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1698 metadata !1, ;; Context
1699 metadata !"Blue", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1700 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1701 i32 4, ;; Line number
1702 i64 32, ;; Size in bits
1703 i64 32, ;; Align in bits
1704 i64 64, ;; Offset in bits
1705 i32 0, ;; Flags
1706 metadata !5 ;; Derived From type
1707}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1708
1709;;
1710;; Define the array of fields used by the composite type Color.
1711;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1712!3 = metadata !{metadata !4, metadata !6, metadata !7}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1713</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1714</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1715
1716</div>
1717
1718<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1719<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1720 <a name="ccxx_enumeration_types">C/C++ enumeration types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1721</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1722
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1723<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1724
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1725<p>Given the following as an example of C/C++ enumeration type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1726
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1727<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1728<pre>
1729enum Trees {
1730 Spruce = 100,
1731 Oak = 200,
1732 Maple = 300
1733};
1734</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1735</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1736
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1737<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1738
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1739<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1740<pre>
1741;;
1742;; Define composite type for enum Trees
1743;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1744!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1745 i32 524292, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1746 metadata !1, ;; Context
1747 metadata !"Trees", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1748 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1749 i32 1, ;; Line number
1750 i64 32, ;; Size in bits
1751 i64 32, ;; Align in bits
1752 i64 0, ;; Offset in bits
1753 i32 0, ;; Flags
1754 null, ;; Derived From type
1755 metadata !3, ;; Elements
1756 i32 0 ;; Runtime language
1757}
Devang Patel2a610c72009-08-25 05:24:07 +0000[diff] [blame]1758
Devang Patel82459882009-08-26 05:01:18 +0000[diff] [blame]1759;;
1760;; Define the array of enumerators used by composite type Trees.
1761;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1762!3 = metadata !{metadata !4, metadata !5, metadata !6}
1763
1764;;
1765;; Define Spruce enumerator.
1766;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1767!4 = metadata !{i32 524328, metadata !"Spruce", i64 100}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1768
1769;;
1770;; Define Oak enumerator.
1771;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1772!5 = metadata !{i32 524328, metadata !"Oak", i64 200}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1773
1774;;
1775;; Define Maple enumerator.
1776;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1777!6 = metadata !{i32 524328, metadata !"Maple", i64 300}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1778
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1779</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1780</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1781
1782</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1783
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1784</div>
1785
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1786<!-- *********************************************************************** -->
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1787
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1788<hr>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1789<address>
1790 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]1791 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1792 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]1793 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1794
1795 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]1796 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1797 Last modified: $Date$
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1798</address>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1799
1800</body>
1801</html>