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NAKAMURA Takumifc8d9302011-04-18 23:59:50 +000011<h1>Source Level Debugging with LLVM</h1>
Chris Lattner1811fca2004-01-05 05:06:33 +000012
Reid Spencerc3c4c4f2004-11-01 08:19:36 +000013<table class="layout" style="width:100%">
14 <tr class="layout">
15 <td class="left">
Chris Lattner1811fca2004-01-05 05:06:33 +000016<ul>
Misha Brukmanf91d9942004-05-12 19:21:57 +000017 <li><a href="#introduction">Introduction</a>
Chris Lattner1811fca2004-01-05 05:06:33 +000018 <ol>
19 <li><a href="#phil">Philosophy behind LLVM debugging information</a></li>
Jim Laskey5dcfd562006-03-23 17:54:33 +000020 <li><a href="#consumers">Debug information consumers</a></li>
Chris Lattner1811fca2004-01-05 05:06:33 +000021 <li><a href="#debugopt">Debugging optimized code</a></li>
Misha Brukmanf91d9942004-05-12 19:21:57 +000022 </ol></li>
Misha Brukmanf91d9942004-05-12 19:21:57 +000023 <li><a href="#format">Debugging information format</a>
Chris Lattner1811fca2004-01-05 05:06:33 +000024 <ol>
Jim Laskey14edc932006-03-14 18:08:46 +000025 <li><a href="#debug_info_descriptors">Debug information descriptors</a>
Chris Lattner1811fca2004-01-05 05:06:33 +000026 <ul>
Jim Laskey14edc932006-03-14 18:08:46 +000027 <li><a href="#format_compile_units">Compile unit descriptors</a></li>
Devang Patel59445db2010-03-09 00:44:10 +000028 <li><a href="#format_files">File descriptors</a></li>
Jim Laskey14edc932006-03-14 18:08:46 +000029 <li><a href="#format_global_variables">Global variable descriptors</a></li>
30 <li><a href="#format_subprograms">Subprogram descriptors</a></li>
Jim Laskey9dcffe72006-03-15 19:10:52 +000031 <li><a href="#format_blocks">Block descriptors</a></li>
Jim Laskey14edc932006-03-14 18:08:46 +000032 <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 Laskey5dcfd562006-03-23 17:54:33 +000037 <li><a href="#format_variables">Local variables</a></li>
Misha Brukmanf91d9942004-05-12 19:21:57 +000038 </ul></li>
Jim Laskey14edc932006-03-14 18:08:46 +000039 <li><a href="#format_common_intrinsics">Debugger intrinsic functions</a>
40 <ul>
Jim Laskey14edc932006-03-14 18:08:46 +000041 <li><a href="#format_common_declare">llvm.dbg.declare</a></li>
Victor Hernandez0b62cc62010-01-11 22:53:48 +000042 <li><a href="#format_common_value">llvm.dbg.value</a></li>
Jim Laskey14edc932006-03-14 18:08:46 +000043 </ul></li>
Misha Brukmanf91d9942004-05-12 19:21:57 +000044 </ol></li>
Devang Patel4da997b2009-11-25 23:28:01 +000045 <li><a href="#format_common_lifetime">Object lifetimes and scoping</a></li>
Misha Brukmanf91d9942004-05-12 19:21:57 +000046 <li><a href="#ccxx_frontend">C/C++ front-end specific debug information</a>
Chris Lattner1811fca2004-01-05 05:06:33 +000047 <ol>
Jim Laskey14edc932006-03-14 18:08:46 +000048 <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 Brukmanf91d9942004-05-12 19:21:57 +000055 </ol></li>
Chris Lattner1811fca2004-01-05 05:06:33 +000056</ul>
Misha Brukmanf91d9942004-05-12 19:21:57 +000057</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +000058<td class="right">
Misha Brukman3c1f8e72004-05-12 21:26:16 +000059<img src="img/venusflytrap.jpg" alt="A leafy and green bug eater" width="247"
Misha Brukmanf91d9942004-05-12 19:21:57 +000060height="369">
61</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +000062</tr></table>
Misha Brukmanf91d9942004-05-12 19:21:57 +000063
Chris Lattner020e1fc2004-05-23 21:07:27 +000064<div class="doc_author">
Jim Laskey14edc932006-03-14 18:08:46 +000065 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
Jim Laskey6e8a2f42007-03-14 19:32:21 +000066 and <a href="mailto:jlaskey@mac.com">Jim Laskey</a></p>
Chris Lattner020e1fc2004-05-23 21:07:27 +000067</div>
68
Chris Lattner1811fca2004-01-05 05:06:33 +000069
70<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +000071<h2><a name="introduction">Introduction</a></h2>
Misha Brukmancda6a9b2004-12-09 20:27:37 +000072<!-- *********************************************************************** -->
Chris Lattner1811fca2004-01-05 05:06:33 +000073
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +000074<div>
Chris Lattner1811fca2004-01-05 05:06:33 +000075
76<p>This document is the central repository for all information pertaining to
Bill Wendlinge9353d72009-05-17 05:52:39 +000077 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 Lattnercb3f64f2009-07-18 21:47:15 +000080 Further, this document provides specific examples of what debug information
Chris Lattner92ec3d12011-01-18 06:12:10 +000081 for C/C++ looks like.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +000082
Chris Lattner1811fca2004-01-05 05:06:33 +000083<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +000084<h3>
Chris Lattner1811fca2004-01-05 05:06:33 +000085 <a name="phil">Philosophy behind LLVM debugging information</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +000086</h3>
Chris Lattner1811fca2004-01-05 05:06:33 +000087
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +000088<div>
Chris Lattner1811fca2004-01-05 05:06:33 +000089
Misha Brukmanf91d9942004-05-12 19:21:57 +000090<p>The idea of the LLVM debugging information is to capture how the important
Bill Wendlinge9353d72009-05-17 05:52:39 +000091 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 Lattner1811fca2004-01-05 05:06:33 +000094
Misha Brukmanf91d9942004-05-12 19:21:57 +000095<ul>
Bill Wendlinge9353d72009-05-17 05:52:39 +000096 <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 Lattner1811fca2004-01-05 05:06:33 +000099
Bill Wendlinge9353d72009-05-17 05:52:39 +0000100 <li>LLVM optimizations should interact in <a href="#debugopt">well-defined and
101 easily described ways</a> with the debugging information.</li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000102
Bill Wendlinge9353d72009-05-17 05:52:39 +0000103 <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 Lattner1811fca2004-01-05 05:06:33 +0000106
Bill Wendlinge9353d72009-05-17 05:52:39 +0000107 <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 Lattner1811fca2004-01-05 05:06:33 +0000110
Bill Wendlinge9353d72009-05-17 05:52:39 +0000111 <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 Brukmanf91d9942004-05-12 19:21:57 +0000115</ul>
Chris Lattner1811fca2004-01-05 05:06:33 +0000116
Bill Wendlinge9353d72009-05-17 05:52:39 +0000117<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 Patel80ae3492009-08-28 23:24:31 +0000120 description of the source-level program is maintained in LLVM metadata
121 in an <a href="#ccxx_frontend">implementation-defined format</a>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000122 (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 Lattner1811fca2004-01-05 05:06:33 +0000125
Jim Laskey14edc932006-03-14 18:08:46 +0000126<p>When a program is being debugged, a debugger interacts with the user and
Bill Wendlinge9353d72009-05-17 05:52:39 +0000127 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 Lattner1811fca2004-01-05 05:06:33 +0000130
131</div>
132
Chris Lattner1811fca2004-01-05 05:06:33 +0000133<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000134<h3>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000135 <a name="consumers">Debug information consumers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000136</h3>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000137
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000138<div>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000139
Jim Laskey5dcfd562006-03-23 17:54:33 +0000140<p>The role of debug information is to provide meta information normally
Bill Wendlinge9353d72009-05-17 05:52:39 +0000141 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 Laskey5dcfd562006-03-23 17:54:33 +0000144
Chris Lattner904f2172010-04-05 04:11:11 +0000145<p>Currently, debug information is consumed by DwarfDebug to produce dwarf
Bill Wendlinge9353d72009-05-17 05:52:39 +0000146 information used by the gdb debugger. Other targets could use the same
147 information to produce stabs or other debug forms.</p>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000148
149<p>It would also be reasonable to use debug information to feed profiling tools
Bill Wendlinge9353d72009-05-17 05:52:39 +0000150 for analysis of generated code, or, tools for reconstructing the original
151 source from generated code.</p>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000152
153<p>TODO - expound a bit more.</p>
154
155</div>
156
157<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000158<h3>
Chris Lattner1811fca2004-01-05 05:06:33 +0000159 <a name="debugopt">Debugging optimized code</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000160</h3>
Chris Lattner1811fca2004-01-05 05:06:33 +0000161
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000162<div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000163
Misha Brukmanf91d9942004-05-12 19:21:57 +0000164<p>An extremely high priority of LLVM debugging information is to make it
Bill Wendlinge9353d72009-05-17 05:52:39 +0000165 interact well with optimizations and analysis. In particular, the LLVM debug
166 information provides the following guarantees:</p>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000167
168<ul>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000169 <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 Lattner1811fca2004-01-05 05:06:33 +0000176
Bill Wendlinge9353d72009-05-17 05:52:39 +0000177 <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 Lattner1811fca2004-01-05 05:06:33 +0000182
Devang Patel5c26a852011-05-31 17:45:27 +0000183 <li>LLVM debug information does not prevent optimizations from
Bill Wendlinge9353d72009-05-17 05:52:39 +0000184 happening (for example inlining, basic block reordering/merging/cleanup,
Devang Patel1d81ea82011-05-31 18:06:14 +0000185 tail duplication, etc).</li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000186
Bill Wendlinge9353d72009-05-17 05:52:39 +0000187 <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 Brukmanf91d9942004-05-12 19:21:57 +0000191</ul>
Chris Lattner1811fca2004-01-05 05:06:33 +0000192
Misha Brukmanf91d9942004-05-12 19:21:57 +0000193<p>Basically, the debug information allows you to compile a program with
Bill Wendlinge9353d72009-05-17 05:52:39 +0000194 "<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 Lattner1811fca2004-01-05 05:06:33 +0000201
Misha Brukman39dcddf2008-12-16 02:54:22 +0000202<p><a href="TestingGuide.html#quicktestsuite">LLVM test suite</a> provides a
Bill Wendlinge9353d72009-05-17 05:52:39 +0000203 framework to test optimizer's handling of debugging information. It can be
204 run like this:</p>
Devang Patelb885a912008-11-21 19:35:57 +0000205
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 Wendlinge9353d72009-05-17 05:52:39 +0000213<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 Patelb885a912008-11-21 19:35:57 +0000217
Chris Lattner1811fca2004-01-05 05:06:33 +0000218</div>
219
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000220</div>
221
Chris Lattner1811fca2004-01-05 05:06:33 +0000222<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000223<h2>
Chris Lattner941515c2004-01-06 05:31:32 +0000224 <a name="format">Debugging information format</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000225</h2>
Chris Lattner1811fca2004-01-05 05:06:33 +0000226<!-- *********************************************************************** -->
227
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000228<div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000229
230<p>LLVM debugging information has been carefully designed to make it possible
Bill Wendlinge9353d72009-05-17 05:52:39 +0000231 for the optimizer to optimize the program and debugging information without
232 necessarily having to know anything about debugging information. In
John Criswell2a4b0802010-03-17 15:01:50 +0000233 particular, the use of metadata avoids duplicated debugging information from
Devang Patel80ae3492009-08-28 23:24:31 +0000234 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 Lattner1811fca2004-01-05 05:06:33 +0000237
238<p>To do this, most of the debugging information (descriptors for types,
Bill Wendlinge9353d72009-05-17 05:52:39 +0000239 variables, functions, source files, etc) is inserted by the language
Devang Patel80ae3492009-08-28 23:24:31 +0000240 front-end in the form of LLVM metadata. </p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000241
Jim Laskey14edc932006-03-14 18:08:46 +0000242<p>Debug information is designed to be agnostic about the target debugger and
Bill Wendlinge9353d72009-05-17 05:52:39 +0000243 debugging information representation (e.g. DWARF/Stabs/etc). It uses a
Devang Patel80ae3492009-08-28 23:24:31 +0000244 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 Lattner1811fca2004-01-05 05:06:33 +0000248
Misha Brukmanf91d9942004-05-12 19:21:57 +0000249<p>To provide basic functionality, the LLVM debugger does have to make some
Bill Wendlinge9353d72009-05-17 05:52:39 +0000250 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 Patel59445db2010-03-09 00:44:10 +0000252 exist are <a href="#format_files">source files</a>,
Bill Wendlinge9353d72009-05-17 05:52:39 +0000253 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 Lattner1811fca2004-01-05 05:06:33 +0000256
257<p>This section of the documentation first describes the representation aspects
Bill Wendlinge9353d72009-05-17 05:52:39 +0000258 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 Lattner1811fca2004-01-05 05:06:33 +0000260
Chris Lattner1811fca2004-01-05 05:06:33 +0000261<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000262<h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000263 <a name="debug_info_descriptors">Debug information descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000264</h3>
Chris Lattner1811fca2004-01-05 05:06:33 +0000265
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000266<div>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000267
Jim Laskey14edc932006-03-14 18:08:46 +0000268<p>In consideration of the complexity and volume of debug information, LLVM
Devang Patel80ae3492009-08-28 23:24:31 +0000269 provides a specification for well formed debug descriptors. </p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000270
Jim Laskey14edc932006-03-14 18:08:46 +0000271<p>Consumers of LLVM debug information expect the descriptors for program
Bill Wendlinge9353d72009-05-17 05:52:39 +0000272 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 Kramer0f420382009-10-12 14:46:08 +0000279 the range 0x1000 through 0x2000 (there is a defined enum DW_TAG_user_base =
Bill Wendlinge9353d72009-05-17 05:52:39 +0000280 0x1000.)</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000281
Devang Patel80ae3492009-08-28 23:24:31 +0000282<p>The fields of debug descriptors used internally by LLVM
Nick Lewyckya87014f2010-03-31 07:50:17 +0000283 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 Lattner1811fca2004-01-05 05:06:33 +0000285
Bill Wendlinge9353d72009-05-17 05:52:39 +0000286<div class="doc_code">
Misha Brukmanf91d9942004-05-12 19:21:57 +0000287<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000288!1 = metadata !{
Nick Lewyckya87014f2010-03-31 07:50:17 +0000289 i32, ;; A tag
Bill Wendlinge9353d72009-05-17 05:52:39 +0000290 ...
291}
Misha Brukmanf91d9942004-05-12 19:21:57 +0000292</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000293</div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000294
Jim Laskeyb2ff2d42006-06-16 13:14:03 +0000295<p><a name="LLVMDebugVersion">The first field of a descriptor is always an
Nick Lewyckya87014f2010-03-31 07:50:17 +0000296 <tt>i32</tt> containing a tag value identifying the content of the
Bill Wendlinge9353d72009-05-17 05:52:39 +0000297 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 Lewyckyf6e37112011-07-25 21:13:23 +0000301 with the current debug version (LLVMDebugVersion = 8 &lt;&lt; 16 or
302 0x80000 or 524288.)</a></p>
Jim Laskey14edc932006-03-14 18:08:46 +0000303
Jim Laskeyb2ff2d42006-06-16 13:14:03 +0000304<p>The details of the various descriptors follow.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000305
Jim Laskey14edc932006-03-14 18:08:46 +0000306<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000307<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000308 <a name="format_compile_units">Compile unit descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000309</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000310
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000311<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000312
Bill Wendlinge9353d72009-05-17 05:52:39 +0000313<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000314<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000315!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
Devang Patel24a674b2011-09-09 17:07:15 +0000327 metadata ;; List of enums types
328 metadata ;; List of retained types
329 metadata ;; List of subprograms
330 metadata ;; List of global variables
Bill Wendlinge9353d72009-05-17 05:52:39 +0000331}
Jim Laskey14edc932006-03-14 18:08:46 +0000332</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000333</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000334
Bill Wendlinge9353d72009-05-17 05:52:39 +0000335<p>These descriptors contain a source language ID for the file (we use the DWARF
336 3.0 ID numbers, such as <tt>DW_LANG_C89</tt>, <tt>DW_LANG_C_plus_plus</tt>,
337 <tt>DW_LANG_Cobol74</tt>, etc), three strings describing the filename,
338 working directory of the compiler, and an identifier string for the compiler
339 that produced it.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000340
Bill Wendlinge9353d72009-05-17 05:52:39 +0000341<p>Compile unit descriptors provide the root context for objects declared in a
Devang Patel09fa69e2011-05-03 16:18:28 +0000342 specific compilation unit. File descriptors are defined using this context.
343 These descriptors are collected by a named metadata
Devang Patel24a674b2011-09-09 17:07:15 +0000344 <tt>!llvm.dbg.cu</tt>. Compile unit descriptor keeps track of subprograms,
345 global variables and type information.
Jim Laskey14edc932006-03-14 18:08:46 +0000346
Devang Patel59445db2010-03-09 00:44:10 +0000347</div>
348
349<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000350<h4>
Devang Patel59445db2010-03-09 00:44:10 +0000351 <a name="format_files">File descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000352</h4>
Devang Patel59445db2010-03-09 00:44:10 +0000353
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000354<div>
Devang Patel59445db2010-03-09 00:44:10 +0000355
356<div class="doc_code">
357<pre>
358!0 = metadata !{
359 i32, ;; Tag = 41 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
360 ;; (DW_TAG_file_type)
361 metadata, ;; Source file name
362 metadata, ;; Source file directory (includes trailing slash)
Devang Pateleb1bb4e2011-08-16 22:09:43 +0000363 metadata ;; Unused
Devang Patel59445db2010-03-09 00:44:10 +0000364}
365</pre>
366</div>
367
John Criswell2a4b0802010-03-17 15:01:50 +0000368<p>These descriptors contain information for a file. Global variables and top
Devang Patel59445db2010-03-09 00:44:10 +0000369 level functions would be defined using this context.k File descriptors also
370 provide context for source line correspondence. </p>
371
372<p>Each input file is encoded as a separate file descriptor in LLVM debugging
Devang Pateleb1bb4e2011-08-16 22:09:43 +0000373 information output. </p>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000374
Jim Laskey14edc932006-03-14 18:08:46 +0000375</div>
376
377<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000378<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000379 <a name="format_global_variables">Global variable descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000380</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000381
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000382<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000383
Bill Wendlinge9353d72009-05-17 05:52:39 +0000384<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000385<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000386!1 = metadata !{
387 i32, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
388 ;; (DW_TAG_variable)
389 i32, ;; Unused field.
390 metadata, ;; Reference to context descriptor
391 metadata, ;; Name
392 metadata, ;; Display name (fully qualified C++ name)
393 metadata, ;; MIPS linkage name (for C++)
Devang Patel59445db2010-03-09 00:44:10 +0000394 metadata, ;; Reference to file where defined
Devang Patel80ae3492009-08-28 23:24:31 +0000395 i32, ;; Line number where defined
396 metadata, ;; Reference to type descriptor
397 i1, ;; True if the global is local to compile unit (static)
398 i1, ;; True if the global is defined in the compile unit (not extern)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000399 {}* ;; Reference to the global variable
Bill Wendlinge9353d72009-05-17 05:52:39 +0000400}
Jim Laskey14edc932006-03-14 18:08:46 +0000401</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000402</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000403
404<p>These descriptors provide debug information about globals variables. The
Devang Patel1c6b6812011-03-29 17:27:08 +0000405provide details such as name, type and where the variable is defined. All
406global variables are collected by named metadata <tt>!llvm.dbg.gv</tt>.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000407
408</div>
409
410<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000411<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000412 <a name="format_subprograms">Subprogram descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000413</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000414
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000415<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000416
Bill Wendlinge9353d72009-05-17 05:52:39 +0000417<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000418<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000419!2 = metadata !{
420 i32, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
421 ;; (DW_TAG_subprogram)
422 i32, ;; Unused field.
423 metadata, ;; Reference to context descriptor
424 metadata, ;; Name
425 metadata, ;; Display name (fully qualified C++ name)
426 metadata, ;; MIPS linkage name (for C++)
Devang Patel59445db2010-03-09 00:44:10 +0000427 metadata, ;; Reference to file where defined
Devang Patel80ae3492009-08-28 23:24:31 +0000428 i32, ;; Line number where defined
429 metadata, ;; Reference to type descriptor
430 i1, ;; True if the global is local to compile unit (static)
Devang Patel1d6bbd42011-04-22 23:10:17 +0000431 i1, ;; True if the global is defined in the compile unit (not extern)
432 i32, ;; Virtuality, e.g. dwarf::DW_VIRTUALITY__virtual
433 i32, ;; Index into a virtual function
Devang Patele89b7592010-06-04 22:49:55 +0000434 metadata, ;; indicates which base type contains the vtable pointer for the
435 ;; derived class
Devang Patel1d6bbd42011-04-22 23:10:17 +0000436 i1, ;; isArtificial
437 i1, ;; isOptimized
438 Function *,;; Pointer to LLVM function
439 metadata, ;; Lists function template parameters
440 metadata ;; Function declaration descriptor
Devang Patel59e27c52011-08-19 23:28:12 +0000441 metadata ;; List of function variables
Bill Wendlinge9353d72009-05-17 05:52:39 +0000442}
Jim Laskey14edc932006-03-14 18:08:46 +0000443</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000444</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000445
446<p>These descriptors provide debug information about functions, methods and
Bill Wendlinge9353d72009-05-17 05:52:39 +0000447 subprograms. They provide details such as name, return types and the source
Devang Patel1c6b6812011-03-29 17:27:08 +0000448 location where the subprogram is defined.
449 All subprogram descriptors are collected by a named metadata
450 <tt>!llvm.dbg.sp</tt>.
451</p>
Jim Laskey9dcffe72006-03-15 19:10:52 +0000452
453</div>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000454
Jim Laskey9dcffe72006-03-15 19:10:52 +0000455<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000456<h4>
Jim Laskey9dcffe72006-03-15 19:10:52 +0000457 <a name="format_blocks">Block descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000458</h4>
Jim Laskey9dcffe72006-03-15 19:10:52 +0000459
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000460<div>
Jim Laskey9dcffe72006-03-15 19:10:52 +0000461
Bill Wendlinge9353d72009-05-17 05:52:39 +0000462<div class="doc_code">
Jim Laskey9dcffe72006-03-15 19:10:52 +0000463<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000464!3 = metadata !{
Devang Patel9fbc6802010-10-04 16:51:59 +0000465 i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
Devang Patelcac38902010-10-01 22:45:00 +0000466 metadata,;; Reference to context descriptor
467 i32, ;; Line number
Devang Patelfb30b852011-03-08 16:25:29 +0000468 i32, ;; Column number
469 metadata,;; Reference to source file
470 i32 ;; Unique ID to identify blocks from a template function
Bill Wendlinge9353d72009-05-17 05:52:39 +0000471}
Jim Laskey9dcffe72006-03-15 19:10:52 +0000472</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000473</div>
Jim Laskey9dcffe72006-03-15 19:10:52 +0000474
Eric Christopher6647b832011-10-11 22:59:11 +0000475<p>This descriptor provides debug information about nested blocks within a
Devang Patelcac38902010-10-01 22:45:00 +0000476 subprogram. The line number and column numbers are used to dinstinguish
477 two lexical blocks at same depth. </p>
Jim Laskey9dcffe72006-03-15 19:10:52 +0000478
Eric Christopher6647b832011-10-11 22:59:11 +0000479<div class="doc_code">
480<pre>
481!3 = metadata !{
482 i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
483 metadata ;; Reference to the scope we're annotating with a file change
484 metadata,;; Reference to the file the scope is enclosed in.
485}
486</pre>
487</div>
488
489<p>This descriptor provides a wrapper around a lexical scope to handle file
490 changes in the middle of a lexical block.</p>
491
Jim Laskey14edc932006-03-14 18:08:46 +0000492</div>
493
494<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000495<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000496 <a name="format_basic_type">Basic type descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000497</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000498
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000499<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000500
Bill Wendlinge9353d72009-05-17 05:52:39 +0000501<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000502<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000503!4 = metadata !{
504 i32, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
505 ;; (DW_TAG_base_type)
Devang Pateleb1bb4e2011-08-16 22:09:43 +0000506 metadata, ;; Reference to context
Devang Patel80ae3492009-08-28 23:24:31 +0000507 metadata, ;; Name (may be "" for anonymous types)
Devang Patel59445db2010-03-09 00:44:10 +0000508 metadata, ;; Reference to file where defined (may be NULL)
Devang Patel80ae3492009-08-28 23:24:31 +0000509 i32, ;; Line number where defined (may be 0)
510 i64, ;; Size in bits
511 i64, ;; Alignment in bits
512 i64, ;; Offset in bits
513 i32, ;; Flags
514 i32 ;; DWARF type encoding
Bill Wendlinge9353d72009-05-17 05:52:39 +0000515}
Jim Laskey14edc932006-03-14 18:08:46 +0000516</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000517</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000518
519<p>These descriptors define primitive types used in the code. Example int, bool
Bill Wendlinge9353d72009-05-17 05:52:39 +0000520 and float. The context provides the scope of the type, which is usually the
Devang Pateleb1bb4e2011-08-16 22:09:43 +0000521 top level. Since basic types are not usually user defined the context
Bill Wendlinge9353d72009-05-17 05:52:39 +0000522 and line number can be left as NULL and 0. The size, alignment and offset
523 are expressed in bits and can be 64 bit values. The alignment is used to
524 round the offset when embedded in a
525 <a href="#format_composite_type">composite type</a> (example to keep float
526 doubles on 64 bit boundaries.) The offset is the bit offset if embedded in
527 a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000528
529<p>The type encoding provides the details of the type. The values are typically
Bill Wendlinge9353d72009-05-17 05:52:39 +0000530 one of the following:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000531
Bill Wendlinge9353d72009-05-17 05:52:39 +0000532<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000533<pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000534DW_ATE_address = 1
535DW_ATE_boolean = 2
536DW_ATE_float = 4
537DW_ATE_signed = 5
538DW_ATE_signed_char = 6
539DW_ATE_unsigned = 7
540DW_ATE_unsigned_char = 8
Jim Laskey14edc932006-03-14 18:08:46 +0000541</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000542</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000543
544</div>
545
546<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000547<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000548 <a name="format_derived_type">Derived type descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000549</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000550
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000551<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000552
Bill Wendlinge9353d72009-05-17 05:52:39 +0000553<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000554<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000555!5 = metadata !{
556 i32, ;; Tag (see below)
557 metadata, ;; Reference to context
558 metadata, ;; Name (may be "" for anonymous types)
Devang Patel59445db2010-03-09 00:44:10 +0000559 metadata, ;; Reference to file where defined (may be NULL)
Devang Patel80ae3492009-08-28 23:24:31 +0000560 i32, ;; Line number where defined (may be 0)
Devang Patelbed5e7d2010-10-01 19:19:30 +0000561 i64, ;; Size in bits
562 i64, ;; Alignment in bits
563 i64, ;; Offset in bits
Devang Patel514b4002011-04-16 00:11:51 +0000564 metadata, ;; Reference to type derived from
565 metadata, ;; (optional) Name of the Objective C property assoicated with
566 ;; Objective-C an ivar
567 metadata, ;; (optional) Name of the Objective C property getter selector.
568 metadata, ;; (optional) Name of the Objective C property setter selector.
569 i32 ;; (optional) Objective C property attributes.
Bill Wendlinge9353d72009-05-17 05:52:39 +0000570}
Jim Laskey14edc932006-03-14 18:08:46 +0000571</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000572</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000573
574<p>These descriptors are used to define types derived from other types. The
575value of the tag varies depending on the meaning. The following are possible
Misha Brukman39dcddf2008-12-16 02:54:22 +0000576tag values:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000577
Bill Wendlinge9353d72009-05-17 05:52:39 +0000578<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000579<pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000580DW_TAG_formal_parameter = 5
581DW_TAG_member = 13
582DW_TAG_pointer_type = 15
583DW_TAG_reference_type = 16
584DW_TAG_typedef = 22
585DW_TAG_const_type = 38
586DW_TAG_volatile_type = 53
587DW_TAG_restrict_type = 55
Jim Laskey14edc932006-03-14 18:08:46 +0000588</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000589</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000590
Bill Wendlinge9353d72009-05-17 05:52:39 +0000591<p><tt>DW_TAG_member</tt> is used to define a member of
592 a <a href="#format_composite_type">composite type</a>
593 or <a href="#format_subprograms">subprogram</a>. The type of the member is
594 the <a href="#format_derived_type">derived
595 type</a>. <tt>DW_TAG_formal_parameter</tt> is used to define a member which
596 is a formal argument of a subprogram.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000597
Bill Wendlinge9353d72009-05-17 05:52:39 +0000598<p><tt>DW_TAG_typedef</tt> is used to provide a name for the derived type.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000599
Bill Wendlinge9353d72009-05-17 05:52:39 +0000600<p><tt>DW_TAG_pointer_type</tt>,<tt>DW_TAG_reference_type</tt>,
601 <tt>DW_TAG_const_type</tt>, <tt>DW_TAG_volatile_type</tt>
602 and <tt>DW_TAG_restrict_type</tt> are used to qualify
603 the <a href="#format_derived_type">derived type</a>. </p>
Jim Laskey14edc932006-03-14 18:08:46 +0000604
605<p><a href="#format_derived_type">Derived type</a> location can be determined
Devang Pateleb1bb4e2011-08-16 22:09:43 +0000606 from the context and line number. The size, alignment and offset are
Bill Wendlinge9353d72009-05-17 05:52:39 +0000607 expressed in bits and can be 64 bit values. The alignment is used to round
608 the offset when embedded in a <a href="#format_composite_type">composite
609 type</a> (example to keep float doubles on 64 bit boundaries.) The offset is
610 the bit offset if embedded in a <a href="#format_composite_type">composite
611 type</a>.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000612
Devang Patel7846c1e2011-02-03 00:22:17 +0000613<p>Note that the <tt>void *</tt> type is expressed as a type derived from NULL.
614</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000615
616</div>
617
618<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000619<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000620 <a name="format_composite_type">Composite type descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000621</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000622
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000623<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000624
Bill Wendlinge9353d72009-05-17 05:52:39 +0000625<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000626<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000627!6 = metadata !{
628 i32, ;; Tag (see below)
629 metadata, ;; Reference to context
630 metadata, ;; Name (may be "" for anonymous types)
Devang Patel59445db2010-03-09 00:44:10 +0000631 metadata, ;; Reference to file where defined (may be NULL)
Devang Patel80ae3492009-08-28 23:24:31 +0000632 i32, ;; Line number where defined (may be 0)
633 i64, ;; Size in bits
634 i64, ;; Alignment in bits
635 i64, ;; Offset in bits
636 i32, ;; Flags
637 metadata, ;; Reference to type derived from
638 metadata, ;; Reference to array of member descriptors
639 i32 ;; Runtime languages
Bill Wendlinge9353d72009-05-17 05:52:39 +0000640}
Jim Laskey14edc932006-03-14 18:08:46 +0000641</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000642</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000643
644<p>These descriptors are used to define types that are composed of 0 or more
645elements. The value of the tag varies depending on the meaning. The following
Misha Brukman39dcddf2008-12-16 02:54:22 +0000646are possible tag values:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000647
Bill Wendlinge9353d72009-05-17 05:52:39 +0000648<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000649<pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000650DW_TAG_array_type = 1
651DW_TAG_enumeration_type = 4
652DW_TAG_structure_type = 19
653DW_TAG_union_type = 23
654DW_TAG_vector_type = 259
Bruno Cardoso Lopes9d809ca2009-05-29 17:08:57 +0000655DW_TAG_subroutine_type = 21
656DW_TAG_inheritance = 28
Jim Laskey14edc932006-03-14 18:08:46 +0000657</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000658</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000659
Jim Laskey19f964e2006-06-15 20:51:43 +0000660<p>The vector flag indicates that an array type is a native packed vector.</p>
661
Jim Laskeyb2ff2d42006-06-16 13:14:03 +0000662<p>The members of array types (tag = <tt>DW_TAG_array_type</tt>) or vector types
Bill Wendlinge9353d72009-05-17 05:52:39 +0000663 (tag = <tt>DW_TAG_vector_type</tt>) are <a href="#format_subrange">subrange
664 descriptors</a>, each representing the range of subscripts at that level of
665 indexing.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000666
667<p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are
Bill Wendlinge9353d72009-05-17 05:52:39 +0000668 <a href="#format_enumeration">enumerator descriptors</a>, each representing
Devang Patel1c6b6812011-03-29 17:27:08 +0000669 the definition of enumeration value for the set. All enumeration type
670 descriptors are collected by named metadata <tt>!llvm.dbg.enum</tt>.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000671
672<p>The members of structure (tag = <tt>DW_TAG_structure_type</tt>) or union (tag
Bill Wendlinge9353d72009-05-17 05:52:39 +0000673 = <tt>DW_TAG_union_type</tt>) types are any one of
674 the <a href="#format_basic_type">basic</a>,
675 <a href="#format_derived_type">derived</a>
676 or <a href="#format_composite_type">composite</a> type descriptors, each
677 representing a field member of the structure or union.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000678
Jim Laskey4771cca2006-08-21 21:21:06 +0000679<p>For C++ classes (tag = <tt>DW_TAG_structure_type</tt>), member descriptors
Bill Wendlinge9353d72009-05-17 05:52:39 +0000680 provide information about base classes, static members and member
681 functions. If a member is a <a href="#format_derived_type">derived type
682 descriptor</a> and has a tag of <tt>DW_TAG_inheritance</tt>, then the type
683 represents a base class. If the member of is
684 a <a href="#format_global_variables">global variable descriptor</a> then it
685 represents a static member. And, if the member is
686 a <a href="#format_subprograms">subprogram descriptor</a> then it represents
687 a member function. For static members and member
688 functions, <tt>getName()</tt> returns the members link or the C++ mangled
689 name. <tt>getDisplayName()</tt> the simplied version of the name.</p>
Jim Laskey4771cca2006-08-21 21:21:06 +0000690
Bill Wendlinge9353d72009-05-17 05:52:39 +0000691<p>The first member of subroutine (tag = <tt>DW_TAG_subroutine_type</tt>) type
692 elements is the return type for the subroutine. The remaining elements are
693 the formal arguments to the subroutine.</p>
Jim Laskey4810c262006-06-20 21:13:20 +0000694
Jim Laskey14edc932006-03-14 18:08:46 +0000695<p><a href="#format_composite_type">Composite type</a> location can be
Devang Pateleb1bb4e2011-08-16 22:09:43 +0000696 determined from the context and line number. The size, alignment and
Bill Wendlinge9353d72009-05-17 05:52:39 +0000697 offset are expressed in bits and can be 64 bit values. The alignment is used
698 to round the offset when embedded in
699 a <a href="#format_composite_type">composite type</a> (as an example, to keep
700 float doubles on 64 bit boundaries.) The offset is the bit offset if embedded
701 in a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000702
703</div>
704
705<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000706<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000707 <a name="format_subrange">Subrange descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000708</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000709
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000710<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000711
Bill Wendlinge9353d72009-05-17 05:52:39 +0000712<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000713<pre>
Devang Patel7846c1e2011-02-03 00:22:17 +0000714!42 = metadata !{
Bill Wendlinge9353d72009-05-17 05:52:39 +0000715 i32, ;; Tag = 33 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subrange_type)
716 i64, ;; Low value
717 i64 ;; High value
718}
Jim Laskey14edc932006-03-14 18:08:46 +0000719</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000720</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000721
722<p>These descriptors are used to define ranges of array subscripts for an array
Bill Wendlinge9353d72009-05-17 05:52:39 +0000723 <a href="#format_composite_type">composite type</a>. The low value defines
724 the lower bounds typically zero for C/C++. The high value is the upper
725 bounds. Values are 64 bit. High - low + 1 is the size of the array. If low
Devang Patel778947c2011-04-08 23:39:38 +0000726 > high the array bounds are not included in generated debugging information.
727</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000728
729</div>
730
731<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000732<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000733 <a name="format_enumeration">Enumerator descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000734</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000735
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000736<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000737
Bill Wendlinge9353d72009-05-17 05:52:39 +0000738<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000739<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000740!6 = metadata !{
741 i32, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
742 ;; (DW_TAG_enumerator)
743 metadata, ;; Name
744 i64 ;; Value
Bill Wendlinge9353d72009-05-17 05:52:39 +0000745}
Jim Laskey14edc932006-03-14 18:08:46 +0000746</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000747</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000748
Bill Wendlinge9353d72009-05-17 05:52:39 +0000749<p>These descriptors are used to define members of an
750 enumeration <a href="#format_composite_type">composite type</a>, it
751 associates the name to the value.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000752
753</div>
754
755<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000756<h4>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000757 <a name="format_variables">Local variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000758</h4>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000759
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000760<div>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000761
762<div class="doc_code">
Jim Laskey5dcfd562006-03-23 17:54:33 +0000763<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000764!7 = metadata !{
765 i32, ;; Tag (see below)
766 metadata, ;; Context
767 metadata, ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000768 metadata, ;; Reference to file where defined
Devang Patele1aa67c2011-03-08 16:29:40 +0000769 i32, ;; 24 bit - Line number where defined
770 ;; 8 bit - Argument number. 1 indicates 1st argument.
Devang Patelac0a1f62011-07-27 18:14:50 +0000771 metadata, ;; Type descriptor
772 i32, ;; flags
773 metadata ;; (optional) Reference to inline location
Bill Wendlinge9353d72009-05-17 05:52:39 +0000774}
Jim Laskey5dcfd562006-03-23 17:54:33 +0000775</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000776</div>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000777
778<p>These descriptors are used to define variables local to a sub program. The
Bill Wendlinge9353d72009-05-17 05:52:39 +0000779 value of the tag depends on the usage of the variable:</p>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000780
Bill Wendlinge9353d72009-05-17 05:52:39 +0000781<div class="doc_code">
Jim Laskey5dcfd562006-03-23 17:54:33 +0000782<pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000783DW_TAG_auto_variable = 256
784DW_TAG_arg_variable = 257
785DW_TAG_return_variable = 258
Jim Laskey5dcfd562006-03-23 17:54:33 +0000786</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000787</div>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000788
789<p>An auto variable is any variable declared in the body of the function. An
Bill Wendlinge9353d72009-05-17 05:52:39 +0000790 argument variable is any variable that appears as a formal argument to the
791 function. A return variable is used to track the result of a function and
792 has no source correspondent.</p>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000793
Jim Laskey3481e122006-03-24 09:20:27 +0000794<p>The context is either the subprogram or block where the variable is defined.
Devang Pateleb1bb4e2011-08-16 22:09:43 +0000795 Name the source variable name. Context and line indicate where the
Bill Wendlinge9353d72009-05-17 05:52:39 +0000796 variable was defined. Type descriptor defines the declared type of the
797 variable.</p>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000798
799</div>
800
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000801</div>
802
Jim Laskey5dcfd562006-03-23 17:54:33 +0000803<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000804<h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000805 <a name="format_common_intrinsics">Debugger intrinsic functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000806</h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000807
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000808<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000809
810<p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to
Bill Wendlinge9353d72009-05-17 05:52:39 +0000811 provide debug information at various points in generated code.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000812
Jim Laskey14edc932006-03-14 18:08:46 +0000813<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000814<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000815 <a name="format_common_declare">llvm.dbg.declare</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000816</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000817
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000818<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000819<pre>
Devang Patel6df452c2010-10-01 19:22:16 +0000820 void %<a href="#format_common_declare">llvm.dbg.declare</a>(metadata, metadata)
Jim Laskey14edc932006-03-14 18:08:46 +0000821</pre>
822
Jim Laskey3481e122006-03-24 09:20:27 +0000823<p>This intrinsic provides information about a local element (ex. variable.) The
NAKAMURA Takumi6bd36d52011-04-09 09:51:57 +0000824 first argument is metadata holding alloca for the variable. The
Devang Patel9a8539c2011-02-01 17:22:12 +0000825 second argument is metadata containing description of the variable. </p>
Jim Laskey14edc932006-03-14 18:08:46 +0000826</div>
827
828<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000829<h4>
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000830 <a name="format_common_value">llvm.dbg.value</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000831</h4>
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000832
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000833<div>
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000834<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000835 void %<a href="#format_common_value">llvm.dbg.value</a>(metadata, i64, metadata)
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000836</pre>
837
838<p>This intrinsic provides information when a user source variable is set to a
839 new value. The first argument is the new value (wrapped as metadata). The
840 second argument is the offset in the user source variable where the new value
Devang Patel9a8539c2011-02-01 17:22:12 +0000841 is written. The third argument is metadata containing description of the
842 user source variable. </p>
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000843</div>
844
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000845</div>
846
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000847<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000848<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000849 <a name="format_common_lifetime">Object lifetimes and scoping</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000850</h3>
Chris Lattner1811fca2004-01-05 05:06:33 +0000851
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000852<div>
Bill Wendling991b84e2009-12-01 00:53:11 +0000853<p>In many languages, the local variables in functions can have their lifetimes
854 or scopes limited to a subset of a function. In the C family of languages,
Bill Wendlinge9353d72009-05-17 05:52:39 +0000855 for example, variables are only live (readable and writable) within the
856 source block that they are defined in. In functional languages, values are
857 only readable after they have been defined. Though this is a very obvious
Bill Wendling991b84e2009-12-01 00:53:11 +0000858 concept, it is non-trivial to model in LLVM, because it has no notion of
Bill Wendlinge9353d72009-05-17 05:52:39 +0000859 scoping in this sense, and does not want to be tied to a language's scoping
860 rules.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000861
Bill Wendling991b84e2009-12-01 00:53:11 +0000862<p>In order to handle this, the LLVM debug format uses the metadata attached to
Nick Lewyckya87014f2010-03-31 07:50:17 +0000863 llvm instructions to encode line number and scoping information. Consider
864 the following C fragment, for example:</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000865
Bill Wendlinge9353d72009-05-17 05:52:39 +0000866<div class="doc_code">
Misha Brukmanf91d9942004-05-12 19:21:57 +0000867<pre>
Chris Lattner1811fca2004-01-05 05:06:33 +00008681. void foo() {
Devang Patel4da997b2009-11-25 23:28:01 +00008692. int X = 21;
8703. int Y = 22;
Chris Lattner1811fca2004-01-05 05:06:33 +00008714. {
Devang Patel4da997b2009-11-25 23:28:01 +00008725. int Z = 23;
8736. Z = X;
Chris Lattner1811fca2004-01-05 05:06:33 +00008747. }
Devang Patel4da997b2009-11-25 23:28:01 +00008758. X = Y;
Chris Lattner1811fca2004-01-05 05:06:33 +00008769. }
Misha Brukmanf91d9942004-05-12 19:21:57 +0000877</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000878</div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000879
Jim Laskey14edc932006-03-14 18:08:46 +0000880<p>Compiled to LLVM, this function would be represented like this:</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000881
Bill Wendlinge9353d72009-05-17 05:52:39 +0000882<div class="doc_code">
Misha Brukmanf91d9942004-05-12 19:21:57 +0000883<pre>
Bill Wendling991b84e2009-12-01 00:53:11 +0000884define void @foo() nounwind ssp {
Jim Laskey14edc932006-03-14 18:08:46 +0000885entry:
Bill Wendling05252352009-12-01 00:59:58 +0000886 %X = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
887 %Y = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
888 %Z = alloca i32, align 4 ; &lt;i32*&gt; [#uses=3]
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000889 %0 = bitcast i32* %X to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel7846c1e2011-02-03 00:22:17 +0000890 call void @llvm.dbg.declare(metadata !{i32 * %X}, metadata !0), !dbg !7
Devang Patel4da997b2009-11-25 23:28:01 +0000891 store i32 21, i32* %X, !dbg !8
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000892 %1 = bitcast i32* %Y to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel7846c1e2011-02-03 00:22:17 +0000893 call void @llvm.dbg.declare(metadata !{i32 * %Y}, metadata !9), !dbg !10
Devang Patel4da997b2009-11-25 23:28:01 +0000894 store i32 22, i32* %Y, !dbg !11
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000895 %2 = bitcast i32* %Z to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel7846c1e2011-02-03 00:22:17 +0000896 call void @llvm.dbg.declare(metadata !{i32 * %Z}, metadata !12), !dbg !14
Devang Patel4da997b2009-11-25 23:28:01 +0000897 store i32 23, i32* %Z, !dbg !15
Bill Wendling05252352009-12-01 00:59:58 +0000898 %tmp = load i32* %X, !dbg !16 ; &lt;i32&gt; [#uses=1]
899 %tmp1 = load i32* %Y, !dbg !16 ; &lt;i32&gt; [#uses=1]
900 %add = add nsw i32 %tmp, %tmp1, !dbg !16 ; &lt;i32&gt; [#uses=1]
Devang Patel4da997b2009-11-25 23:28:01 +0000901 store i32 %add, i32* %Z, !dbg !16
Bill Wendling05252352009-12-01 00:59:58 +0000902 %tmp2 = load i32* %Y, !dbg !17 ; &lt;i32&gt; [#uses=1]
Devang Patel4da997b2009-11-25 23:28:01 +0000903 store i32 %tmp2, i32* %X, !dbg !17
904 ret void, !dbg !18
Chris Lattner1811fca2004-01-05 05:06:33 +0000905}
Devang Patel4da997b2009-11-25 23:28:01 +0000906
Devang Patel7846c1e2011-02-03 00:22:17 +0000907declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
Devang Patel4da997b2009-11-25 23:28:01 +0000908
909!0 = metadata !{i32 459008, metadata !1, metadata !"X",
910 metadata !3, i32 2, metadata !6}; [ DW_TAG_auto_variable ]
911!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
912!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo", metadata !"foo",
913 metadata !"foo", metadata !3, i32 1, metadata !4,
914 i1 false, i1 true}; [DW_TAG_subprogram ]
915!3 = metadata !{i32 458769, i32 0, i32 12, metadata !"foo.c",
916 metadata !"/private/tmp", metadata !"clang 1.1", i1 true,
917 i1 false, metadata !"", i32 0}; [DW_TAG_compile_unit ]
918!4 = metadata !{i32 458773, metadata !3, metadata !"", null, i32 0, i64 0, i64 0,
919 i64 0, i32 0, null, metadata !5, i32 0}; [DW_TAG_subroutine_type ]
920!5 = metadata !{null}
921!6 = metadata !{i32 458788, metadata !3, metadata !"int", metadata !3, i32 0,
922 i64 32, i64 32, i64 0, i32 0, i32 5}; [DW_TAG_base_type ]
923!7 = metadata !{i32 2, i32 7, metadata !1, null}
924!8 = metadata !{i32 2, i32 3, metadata !1, null}
925!9 = metadata !{i32 459008, metadata !1, metadata !"Y", metadata !3, i32 3,
926 metadata !6}; [ DW_TAG_auto_variable ]
927!10 = metadata !{i32 3, i32 7, metadata !1, null}
928!11 = metadata !{i32 3, i32 3, metadata !1, null}
929!12 = metadata !{i32 459008, metadata !13, metadata !"Z", metadata !3, i32 5,
930 metadata !6}; [ DW_TAG_auto_variable ]
931!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
932!14 = metadata !{i32 5, i32 9, metadata !13, null}
933!15 = metadata !{i32 5, i32 5, metadata !13, null}
934!16 = metadata !{i32 6, i32 5, metadata !13, null}
935!17 = metadata !{i32 8, i32 3, metadata !1, null}
936!18 = metadata !{i32 9, i32 1, metadata !2, null}
Misha Brukmanf91d9942004-05-12 19:21:57 +0000937</pre>
Chris Lattner1811fca2004-01-05 05:06:33 +0000938</div>
939
Bill Wendling991b84e2009-12-01 00:53:11 +0000940<p>This example illustrates a few important details about LLVM debugging
941 information. In particular, it shows how the <tt>llvm.dbg.declare</tt>
942 intrinsic and location information, which are attached to an instruction,
943 are applied together to allow a debugger to analyze the relationship between
944 statements, variable definitions, and the code used to implement the
945 function.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000946
Bill Wendling991b84e2009-12-01 00:53:11 +0000947<div class="doc_code">
Bill Wendling05252352009-12-01 00:59:58 +0000948<pre>
Devang Patel7846c1e2011-02-03 00:22:17 +0000949call void @llvm.dbg.declare(metadata, metadata !0), !dbg !7
Bill Wendling991b84e2009-12-01 00:53:11 +0000950</pre>
951</div>
952
953<p>The first intrinsic
Devang Patel4da997b2009-11-25 23:28:01 +0000954 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendling991b84e2009-12-01 00:53:11 +0000955 encodes debugging information for the variable <tt>X</tt>. The metadata
956 <tt>!dbg !7</tt> attached to the intrinsic provides scope information for the
957 variable <tt>X</tt>.</p>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000958
Bill Wendling991b84e2009-12-01 00:53:11 +0000959<div class="doc_code">
960<pre>
961!7 = metadata !{i32 2, i32 7, metadata !1, null}
962!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
963!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo",
964 metadata !"foo", metadata !"foo", metadata !3, i32 1,
965 metadata !4, i1 false, i1 true}; [DW_TAG_subprogram ]
966</pre>
967</div>
968
969<p>Here <tt>!7</tt> is metadata providing location information. It has four
970 fields: line number, column number, scope, and original scope. The original
971 scope represents inline location if this instruction is inlined inside a
972 caller, and is null otherwise. In this example, scope is encoded by
Devang Patel4da997b2009-11-25 23:28:01 +0000973 <tt>!1</tt>. <tt>!1</tt> represents a lexical block inside the scope
974 <tt>!2</tt>, where <tt>!2</tt> is a
Bill Wendling991b84e2009-12-01 00:53:11 +0000975 <a href="#format_subprograms">subprogram descriptor</a>. This way the
976 location information attached to the intrinsics indicates that the
977 variable <tt>X</tt> is declared at line number 2 at a function level scope in
978 function <tt>foo</tt>.</p>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000979
Devang Patel4da997b2009-11-25 23:28:01 +0000980<p>Now lets take another example.</p>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000981
Bill Wendling991b84e2009-12-01 00:53:11 +0000982<div class="doc_code">
Bill Wendling05252352009-12-01 00:59:58 +0000983<pre>
Devang Patel7846c1e2011-02-03 00:22:17 +0000984call void @llvm.dbg.declare(metadata, metadata !12), !dbg !14
Bill Wendling991b84e2009-12-01 00:53:11 +0000985</pre>
986</div>
987
988<p>The second intrinsic
Devang Patel4da997b2009-11-25 23:28:01 +0000989 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendling991b84e2009-12-01 00:53:11 +0000990 encodes debugging information for variable <tt>Z</tt>. The metadata
991 <tt>!dbg !14</tt> attached to the intrinsic provides scope information for
992 the variable <tt>Z</tt>.</p>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000993
Bill Wendling991b84e2009-12-01 00:53:11 +0000994<div class="doc_code">
995<pre>
996!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
997!14 = metadata !{i32 5, i32 9, metadata !13, null}
998</pre>
999</div>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001000
John Criswell2a4b0802010-03-17 15:01:50 +00001001<p>Here <tt>!14</tt> indicates that <tt>Z</tt> is declared at line number 5 and
Bill Wendling991b84e2009-12-01 00:53:11 +00001002 column number 9 inside of lexical scope <tt>!13</tt>. The lexical scope
1003 itself resides inside of lexical scope <tt>!1</tt> described above.</p>
1004
1005<p>The scope information attached with each instruction provides a
1006 straightforward way to find instructions covered by a scope.</p>
1007
Bill Wendlinge9353d72009-05-17 05:52:39 +00001008</div>
Chris Lattner1811fca2004-01-05 05:06:33 +00001009
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001010</div>
1011
Chris Lattner1811fca2004-01-05 05:06:33 +00001012<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001013<h2>
Chris Lattner941515c2004-01-06 05:31:32 +00001014 <a name="ccxx_frontend">C/C++ front-end specific debug information</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001015</h2>
Misha Brukmancda6a9b2004-12-09 20:27:37 +00001016<!-- *********************************************************************** -->
Chris Lattner1811fca2004-01-05 05:06:33 +00001017
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001018<div>
Chris Lattner1811fca2004-01-05 05:06:33 +00001019
Misha Brukmanf91d9942004-05-12 19:21:57 +00001020<p>The C and C++ front-ends represent information about the program in a format
Bill Wendlinge9353d72009-05-17 05:52:39 +00001021 that is effectively identical
1022 to <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3.0</a> in
1023 terms of information content. This allows code generators to trivially
1024 support native debuggers by generating standard dwarf information, and
1025 contains enough information for non-dwarf targets to translate it as
1026 needed.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +00001027
Jim Laskey14edc932006-03-14 18:08:46 +00001028<p>This section describes the forms used to represent C and C++ programs. Other
Bill Wendlinge9353d72009-05-17 05:52:39 +00001029 languages could pattern themselves after this (which itself is tuned to
1030 representing programs in the same way that DWARF 3 does), or they could
1031 choose to provide completely different forms if they don't fit into the DWARF
1032 model. As support for debugging information gets added to the various LLVM
1033 source-language front-ends, the information used should be documented
1034 here.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +00001035
Jim Laskey14edc932006-03-14 18:08:46 +00001036<p>The following sections provide examples of various C/C++ constructs and the
Bill Wendlinge9353d72009-05-17 05:52:39 +00001037 debug information that would best describe those constructs.</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001038
Chris Lattner1811fca2004-01-05 05:06:33 +00001039<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001040<h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001041 <a name="ccxx_compile_units">C/C++ source file information</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001042</h3>
Chris Lattner1811fca2004-01-05 05:06:33 +00001043
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001044<div>
Chris Lattner1811fca2004-01-05 05:06:33 +00001045
Bill Wendlinge9353d72009-05-17 05:52:39 +00001046<p>Given the source files <tt>MySource.cpp</tt> and <tt>MyHeader.h</tt> located
1047 in the directory <tt>/Users/mine/sources</tt>, the following code:</p>
Chris Lattner941515c2004-01-06 05:31:32 +00001048
Bill Wendlinge9353d72009-05-17 05:52:39 +00001049<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001050<pre>
1051#include "MyHeader.h"
Chris Lattner941515c2004-01-06 05:31:32 +00001052
Jim Laskey14edc932006-03-14 18:08:46 +00001053int main(int argc, char *argv[]) {
1054 return 0;
1055}
1056</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001057</div>
Chris Lattner941515c2004-01-06 05:31:32 +00001058
Misha Brukman39dcddf2008-12-16 02:54:22 +00001059<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001060
Bill Wendlinge9353d72009-05-17 05:52:39 +00001061<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001062<pre>
1063...
1064;;
Devang Patel59445db2010-03-09 00:44:10 +00001065;; Define the compile unit for the main source file "/Users/mine/sources/MySource.cpp".
Jim Laskey14edc932006-03-14 18:08:46 +00001066;;
Devang Patel59445db2010-03-09 00:44:10 +00001067!2 = metadata !{
1068 i32 524305, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001069 i32 0, ;; Unused
1070 i32 4, ;; Language Id
1071 metadata !"MySource.cpp",
1072 metadata !"/Users/mine/sources",
1073 metadata !"4.2.1 (Based on Apple Inc. build 5649) (LLVM build 00)",
1074 i1 true, ;; Main Compile Unit
1075 i1 false, ;; Optimized compile unit
1076 metadata !"", ;; Compiler flags
1077 i32 0} ;; Runtime version
1078
Jim Laskey14edc932006-03-14 18:08:46 +00001079;;
Devang Patel59445db2010-03-09 00:44:10 +00001080;; Define the file for the file "/Users/mine/sources/MySource.cpp".
Jim Laskey14edc932006-03-14 18:08:46 +00001081;;
Devang Patel80ae3492009-08-28 23:24:31 +00001082!1 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001083 i32 524329, ;; Tag
1084 metadata !"MySource.cpp",
Devang Patel80ae3492009-08-28 23:24:31 +00001085 metadata !"/Users/mine/sources",
Devang Patel4a7904d62010-07-13 16:53:20 +00001086 metadata !2 ;; Compile unit
Devang Patel59445db2010-03-09 00:44:10 +00001087}
1088
1089;;
1090;; Define the file for the file "/Users/mine/sources/Myheader.h"
1091;;
1092!3 = metadata !{
1093 i32 524329, ;; Tag
1094 metadata !"Myheader.h"
1095 metadata !"/Users/mine/sources",
Devang Patel4a7904d62010-07-13 16:53:20 +00001096 metadata !2 ;; Compile unit
Devang Patel59445db2010-03-09 00:44:10 +00001097}
Jim Laskey14edc932006-03-14 18:08:46 +00001098
Jim Laskey14edc932006-03-14 18:08:46 +00001099...
1100</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001101</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001102
Devang Patel5bc1c4b2010-03-26 19:08:36 +00001103<p>llvm::Instruction provides easy access to metadata attached with an
1104instruction. One can extract line number information encoded in LLVM IR
1105using <tt>Instruction::getMetadata()</tt> and
1106<tt>DILocation::getLineNumber()</tt>.
1107<pre>
1108 if (MDNode *N = I->getMetadata("dbg")) { // Here I is an LLVM instruction
1109 DILocation Loc(N); // DILocation is in DebugInfo.h
1110 unsigned Line = Loc.getLineNumber();
1111 StringRef File = Loc.getFilename();
1112 StringRef Dir = Loc.getDirectory();
1113 }
1114</pre>
Chris Lattner941515c2004-01-06 05:31:32 +00001115</div>
1116
1117<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001118<h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001119 <a name="ccxx_global_variable">C/C++ global variable information</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001120</h3>
Chris Lattner941515c2004-01-06 05:31:32 +00001121
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001122<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001123
Misha Brukman39dcddf2008-12-16 02:54:22 +00001124<p>Given an integer global variable declared as follows:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001125
Bill Wendlinge9353d72009-05-17 05:52:39 +00001126<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001127<pre>
1128int MyGlobal = 100;
1129</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001130</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001131
Misha Brukman39dcddf2008-12-16 02:54:22 +00001132<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001133
Bill Wendlinge9353d72009-05-17 05:52:39 +00001134<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001135<pre>
1136;;
Jim Laskey14edc932006-03-14 18:08:46 +00001137;; Define the global itself.
1138;;
1139%MyGlobal = global int 100
1140...
1141;;
Devang Patel80ae3492009-08-28 23:24:31 +00001142;; List of debug info of globals
Jim Laskey14edc932006-03-14 18:08:46 +00001143;;
Devang Patel80ae3492009-08-28 23:24:31 +00001144!llvm.dbg.gv = !{!0}
Jim Laskey14edc932006-03-14 18:08:46 +00001145
1146;;
1147;; Define the global variable descriptor. Note the reference to the global
1148;; variable anchor and the global variable itself.
1149;;
Devang Patel80ae3492009-08-28 23:24:31 +00001150!0 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001151 i32 524340, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001152 i32 0, ;; Unused
1153 metadata !1, ;; Context
1154 metadata !"MyGlobal", ;; Name
1155 metadata !"MyGlobal", ;; Display Name
1156 metadata !"MyGlobal", ;; Linkage Name
Devang Patel59445db2010-03-09 00:44:10 +00001157 metadata !3, ;; Compile Unit
Devang Patel80ae3492009-08-28 23:24:31 +00001158 i32 1, ;; Line Number
Devang Patel59445db2010-03-09 00:44:10 +00001159 metadata !4, ;; Type
Devang Patel80ae3492009-08-28 23:24:31 +00001160 i1 false, ;; Is a local variable
1161 i1 true, ;; Is this a definition
1162 i32* @MyGlobal ;; The global variable
1163}
1164
Jim Laskey14edc932006-03-14 18:08:46 +00001165;;
1166;; Define the basic type of 32 bit signed integer. Note that since int is an
1167;; intrinsic type the source file is NULL and line 0.
1168;;
Devang Patel59445db2010-03-09 00:44:10 +00001169!4 = metadata !{
1170 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001171 metadata !1, ;; Context
1172 metadata !"int", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001173 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001174 i32 0, ;; Line number
1175 i64 32, ;; Size in Bits
1176 i64 32, ;; Align in Bits
1177 i64 0, ;; Offset in Bits
1178 i32 0, ;; Flags
1179 i32 5 ;; Encoding
1180}
Jim Laskey14edc932006-03-14 18:08:46 +00001181
Jim Laskey14edc932006-03-14 18:08:46 +00001182</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001183</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001184
Chris Lattner941515c2004-01-06 05:31:32 +00001185</div>
Chris Lattner1811fca2004-01-05 05:06:33 +00001186
Jim Laskey14edc932006-03-14 18:08:46 +00001187<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001188<h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001189 <a name="ccxx_subprogram">C/C++ function information</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001190</h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001191
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001192<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001193
Misha Brukman39dcddf2008-12-16 02:54:22 +00001194<p>Given a function declared as follows:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001195
Bill Wendlinge9353d72009-05-17 05:52:39 +00001196<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001197<pre>
1198int main(int argc, char *argv[]) {
1199 return 0;
1200}
1201</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001202</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001203
Misha Brukman39dcddf2008-12-16 02:54:22 +00001204<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001205
Bill Wendlinge9353d72009-05-17 05:52:39 +00001206<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001207<pre>
1208;;
Jim Laskey14edc932006-03-14 18:08:46 +00001209;; Define the anchor for subprograms. Note that the second field of the
1210;; anchor is 46, which is the same as the tag for subprograms
1211;; (46 = DW_TAG_subprogram.)
1212;;
Devang Patel59445db2010-03-09 00:44:10 +00001213!6 = metadata !{
1214 i32 524334, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001215 i32 0, ;; Unused
1216 metadata !1, ;; Context
1217 metadata !"main", ;; Name
1218 metadata !"main", ;; Display name
1219 metadata !"main", ;; Linkage name
Devang Patel59445db2010-03-09 00:44:10 +00001220 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001221 i32 1, ;; Line number
Devang Patel59445db2010-03-09 00:44:10 +00001222 metadata !4, ;; Type
Devang Patel80ae3492009-08-28 23:24:31 +00001223 i1 false, ;; Is local
Devang Patel9f738842011-04-05 22:52:06 +00001224 i1 true, ;; Is definition
1225 i32 0, ;; Virtuality attribute, e.g. pure virtual function
1226 i32 0, ;; Index into virtual table for C++ methods
1227 i32 0, ;; Type that holds virtual table.
1228 i32 0, ;; Flags
1229 i1 false, ;; True if this function is optimized
1230 Function *, ;; Pointer to llvm::Function
1231 null ;; Function template parameters
Devang Patel80ae3492009-08-28 23:24:31 +00001232}
Jim Laskey14edc932006-03-14 18:08:46 +00001233;;
1234;; Define the subprogram itself.
1235;;
Devang Patel80ae3492009-08-28 23:24:31 +00001236define i32 @main(i32 %argc, i8** %argv) {
Jim Laskey14edc932006-03-14 18:08:46 +00001237...
1238}
1239</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001240</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001241
1242</div>
1243
1244<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001245<h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001246 <a name="ccxx_basic_types">C/C++ basic types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001247</h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001248
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001249<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001250
Misha Brukman39dcddf2008-12-16 02:54:22 +00001251<p>The following are the basic type descriptors for C/C++ core types:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001252
Jim Laskey14edc932006-03-14 18:08:46 +00001253<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001254<h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001255 <a name="ccxx_basic_type_bool">bool</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001256</h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001257
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001258<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001259
Bill Wendlinge9353d72009-05-17 05:52:39 +00001260<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001261<pre>
Devang Patel80ae3492009-08-28 23:24:31 +00001262!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001263 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001264 metadata !1, ;; Context
1265 metadata !"bool", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001266 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001267 i32 0, ;; Line number
1268 i64 8, ;; Size in Bits
1269 i64 8, ;; Align in Bits
1270 i64 0, ;; Offset in Bits
1271 i32 0, ;; Flags
1272 i32 2 ;; Encoding
1273}
Jim Laskey14edc932006-03-14 18:08:46 +00001274</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001275</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001276
1277</div>
1278
1279<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001280<h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001281 <a name="ccxx_basic_char">char</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001282</h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001283
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001284<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001285
Bill Wendlinge9353d72009-05-17 05:52:39 +00001286<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001287<pre>
Devang Patel80ae3492009-08-28 23:24:31 +00001288!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001289 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001290 metadata !1, ;; Context
1291 metadata !"char", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001292 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001293 i32 0, ;; Line number
1294 i64 8, ;; Size in Bits
1295 i64 8, ;; Align in Bits
1296 i64 0, ;; Offset in Bits
1297 i32 0, ;; Flags
1298 i32 6 ;; Encoding
1299}
Jim Laskey14edc932006-03-14 18:08:46 +00001300</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001301</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001302
1303</div>
1304
1305<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001306<h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001307 <a name="ccxx_basic_unsigned_char">unsigned char</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001308</h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001309
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001310<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001311
Bill Wendlinge9353d72009-05-17 05:52:39 +00001312<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001313<pre>
Devang Patel80ae3492009-08-28 23:24:31 +00001314!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001315 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001316 metadata !1, ;; Context
1317 metadata !"unsigned char",
Devang Patel59445db2010-03-09 00:44:10 +00001318 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001319 i32 0, ;; Line number
1320 i64 8, ;; Size in Bits
1321 i64 8, ;; Align in Bits
1322 i64 0, ;; Offset in Bits
1323 i32 0, ;; Flags
1324 i32 8 ;; Encoding
1325}
Jim Laskey14edc932006-03-14 18:08:46 +00001326</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001327</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001328
1329</div>
1330
1331<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001332<h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001333 <a name="ccxx_basic_short">short</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001334</h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001335
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001336<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001337
Bill Wendlinge9353d72009-05-17 05:52:39 +00001338<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001339<pre>
Devang Patel80ae3492009-08-28 23:24:31 +00001340!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001341 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001342 metadata !1, ;; Context
1343 metadata !"short int",
Devang Patel59445db2010-03-09 00:44:10 +00001344 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001345 i32 0, ;; Line number
1346 i64 16, ;; Size in Bits
1347 i64 16, ;; Align in Bits
1348 i64 0, ;; Offset in Bits
1349 i32 0, ;; Flags
1350 i32 5 ;; Encoding
1351}
Jim Laskey14edc932006-03-14 18:08:46 +00001352</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001353</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001354
1355</div>
1356
1357<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001358<h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001359 <a name="ccxx_basic_unsigned_short">unsigned short</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001360</h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001361
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001362<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001363
Bill Wendlinge9353d72009-05-17 05:52:39 +00001364<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001365<pre>
Devang Patel80ae3492009-08-28 23:24:31 +00001366!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001367 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001368 metadata !1, ;; Context
1369 metadata !"short unsigned int",
Devang Patel59445db2010-03-09 00:44:10 +00001370 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001371 i32 0, ;; Line number
1372 i64 16, ;; Size in Bits
1373 i64 16, ;; Align in Bits
1374 i64 0, ;; Offset in Bits
1375 i32 0, ;; Flags
1376 i32 7 ;; Encoding
1377}
Jim Laskey14edc932006-03-14 18:08:46 +00001378</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001379</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001380
1381</div>
1382
1383<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001384<h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001385 <a name="ccxx_basic_int">int</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001386</h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001387
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001388<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001389
Bill Wendlinge9353d72009-05-17 05:52:39 +00001390<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001391<pre>
Devang Patel80ae3492009-08-28 23:24:31 +00001392!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001393 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001394 metadata !1, ;; Context
1395 metadata !"int", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001396 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001397 i32 0, ;; Line number
1398 i64 32, ;; Size in Bits
1399 i64 32, ;; Align in Bits
1400 i64 0, ;; Offset in Bits
1401 i32 0, ;; Flags
1402 i32 5 ;; Encoding
1403}
Bill Wendlinge9353d72009-05-17 05:52:39 +00001404</pre></div>
Jim Laskey14edc932006-03-14 18:08:46 +00001405
1406</div>
1407
1408<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001409<h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001410 <a name="ccxx_basic_unsigned_int">unsigned int</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001411</h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001412
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001413<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001414
Bill Wendlinge9353d72009-05-17 05:52:39 +00001415<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001416<pre>
Devang Patel80ae3492009-08-28 23:24:31 +00001417!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001418 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001419 metadata !1, ;; Context
1420 metadata !"unsigned int",
Devang Patel59445db2010-03-09 00:44:10 +00001421 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001422 i32 0, ;; Line number
1423 i64 32, ;; Size in Bits
1424 i64 32, ;; Align in Bits
1425 i64 0, ;; Offset in Bits
1426 i32 0, ;; Flags
1427 i32 7 ;; Encoding
1428}
Jim Laskey14edc932006-03-14 18:08:46 +00001429</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001430</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001431
1432</div>
1433
1434<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001435<h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001436 <a name="ccxx_basic_long_long">long long</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001437</h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001438
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001439<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001440
Bill Wendlinge9353d72009-05-17 05:52:39 +00001441<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001442<pre>
Devang Patel80ae3492009-08-28 23:24:31 +00001443!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001444 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001445 metadata !1, ;; Context
1446 metadata !"long long int",
Devang Patel59445db2010-03-09 00:44:10 +00001447 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001448 i32 0, ;; Line number
1449 i64 64, ;; Size in Bits
1450 i64 64, ;; Align in Bits
1451 i64 0, ;; Offset in Bits
1452 i32 0, ;; Flags
1453 i32 5 ;; Encoding
1454}
Jim Laskey14edc932006-03-14 18:08:46 +00001455</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001456</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001457
1458</div>
1459
1460<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001461<h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001462 <a name="ccxx_basic_unsigned_long_long">unsigned long long</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001463</h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001464
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001465<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001466
Bill Wendlinge9353d72009-05-17 05:52:39 +00001467<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001468<pre>
Devang Patel80ae3492009-08-28 23:24:31 +00001469!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001470 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001471 metadata !1, ;; Context
1472 metadata !"long long unsigned int",
Devang Patel59445db2010-03-09 00:44:10 +00001473 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001474 i32 0, ;; Line number
1475 i64 64, ;; Size in Bits
1476 i64 64, ;; Align in Bits
1477 i64 0, ;; Offset in Bits
1478 i32 0, ;; Flags
1479 i32 7 ;; Encoding
1480}
Jim Laskey14edc932006-03-14 18:08:46 +00001481</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001482</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001483
1484</div>
1485
1486<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001487<h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001488 <a name="ccxx_basic_float">float</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001489</h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001490
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001491<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001492
Bill Wendlinge9353d72009-05-17 05:52:39 +00001493<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001494<pre>
Devang Patel80ae3492009-08-28 23:24:31 +00001495!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001496 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001497 metadata !1, ;; Context
1498 metadata !"float",
Devang Patel59445db2010-03-09 00:44:10 +00001499 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001500 i32 0, ;; Line number
1501 i64 32, ;; Size in Bits
1502 i64 32, ;; Align in Bits
1503 i64 0, ;; Offset in Bits
1504 i32 0, ;; Flags
1505 i32 4 ;; Encoding
1506}
Jim Laskey14edc932006-03-14 18:08:46 +00001507</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001508</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001509
1510</div>
1511
1512<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001513<h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001514 <a name="ccxx_basic_double">double</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001515</h4>
Jim Laskey14edc932006-03-14 18:08:46 +00001516
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001517<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001518
Bill Wendlinge9353d72009-05-17 05:52:39 +00001519<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001520<pre>
Devang Patel80ae3492009-08-28 23:24:31 +00001521!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001522 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001523 metadata !1, ;; Context
1524 metadata !"double",;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001525 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001526 i32 0, ;; Line number
1527 i64 64, ;; Size in Bits
1528 i64 64, ;; Align in Bits
1529 i64 0, ;; Offset in Bits
1530 i32 0, ;; Flags
1531 i32 4 ;; Encoding
1532}
Jim Laskey14edc932006-03-14 18:08:46 +00001533</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001534</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001535
1536</div>
1537
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001538</div>
1539
Jim Laskey14edc932006-03-14 18:08:46 +00001540<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001541<h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001542 <a name="ccxx_derived_types">C/C++ derived types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001543</h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001544
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001545<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001546
Misha Brukman39dcddf2008-12-16 02:54:22 +00001547<p>Given the following as an example of C/C++ derived type:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001548
Bill Wendlinge9353d72009-05-17 05:52:39 +00001549<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001550<pre>
1551typedef const int *IntPtr;
1552</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001553</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001554
Misha Brukman39dcddf2008-12-16 02:54:22 +00001555<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001556
Bill Wendlinge9353d72009-05-17 05:52:39 +00001557<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001558<pre>
1559;;
1560;; Define the typedef "IntPtr".
1561;;
Devang Patel80ae3492009-08-28 23:24:31 +00001562!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001563 i32 524310, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001564 metadata !1, ;; Context
1565 metadata !"IntPtr", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001566 metadata !3, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001567 i32 0, ;; Line number
1568 i64 0, ;; Size in bits
1569 i64 0, ;; Align in bits
1570 i64 0, ;; Offset in bits
1571 i32 0, ;; Flags
1572 metadata !4 ;; Derived From type
1573}
Jim Laskey14edc932006-03-14 18:08:46 +00001574
1575;;
1576;; Define the pointer type.
1577;;
Devang Patel80ae3492009-08-28 23:24:31 +00001578!4 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001579 i32 524303, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001580 metadata !1, ;; Context
1581 metadata !"", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001582 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001583 i32 0, ;; Line number
1584 i64 64, ;; Size in bits
1585 i64 64, ;; Align in bits
1586 i64 0, ;; Offset in bits
1587 i32 0, ;; Flags
1588 metadata !5 ;; Derived From type
1589}
Jim Laskey14edc932006-03-14 18:08:46 +00001590;;
1591;; Define the const type.
1592;;
Devang Patel80ae3492009-08-28 23:24:31 +00001593!5 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001594 i32 524326, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001595 metadata !1, ;; Context
1596 metadata !"", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001597 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001598 i32 0, ;; Line number
1599 i64 32, ;; Size in bits
1600 i64 32, ;; Align in bits
1601 i64 0, ;; Offset in bits
1602 i32 0, ;; Flags
1603 metadata !6 ;; Derived From type
1604}
Jim Laskey14edc932006-03-14 18:08:46 +00001605;;
1606;; Define the int type.
1607;;
Devang Patel80ae3492009-08-28 23:24:31 +00001608!6 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001609 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001610 metadata !1, ;; Context
1611 metadata !"int", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001612 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001613 i32 0, ;; Line number
1614 i64 32, ;; Size in bits
1615 i64 32, ;; Align in bits
1616 i64 0, ;; Offset in bits
1617 i32 0, ;; Flags
1618 5 ;; Encoding
1619}
Jim Laskey14edc932006-03-14 18:08:46 +00001620</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001621</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001622
1623</div>
1624
1625<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001626<h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001627 <a name="ccxx_composite_types">C/C++ struct/union types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001628</h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001629
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001630<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001631
Misha Brukman39dcddf2008-12-16 02:54:22 +00001632<p>Given the following as an example of C/C++ struct type:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001633
Bill Wendlinge9353d72009-05-17 05:52:39 +00001634<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001635<pre>
1636struct Color {
1637 unsigned Red;
1638 unsigned Green;
1639 unsigned Blue;
1640};
1641</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001642</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001643
Misha Brukman39dcddf2008-12-16 02:54:22 +00001644<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001645
Bill Wendlinge9353d72009-05-17 05:52:39 +00001646<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001647<pre>
1648;;
1649;; Define basic type for unsigned int.
1650;;
Devang Patel80ae3492009-08-28 23:24:31 +00001651!5 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001652 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001653 metadata !1, ;; Context
1654 metadata !"unsigned int",
Devang Patel59445db2010-03-09 00:44:10 +00001655 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001656 i32 0, ;; Line number
1657 i64 32, ;; Size in Bits
1658 i64 32, ;; Align in Bits
1659 i64 0, ;; Offset in Bits
1660 i32 0, ;; Flags
1661 i32 7 ;; Encoding
1662}
Jim Laskey14edc932006-03-14 18:08:46 +00001663;;
1664;; Define composite type for struct Color.
1665;;
Devang Patel80ae3492009-08-28 23:24:31 +00001666!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001667 i32 524307, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001668 metadata !1, ;; Context
1669 metadata !"Color", ;; Name
1670 metadata !1, ;; Compile unit
1671 i32 1, ;; Line number
1672 i64 96, ;; Size in bits
1673 i64 32, ;; Align in bits
1674 i64 0, ;; Offset in bits
1675 i32 0, ;; Flags
1676 null, ;; Derived From
1677 metadata !3, ;; Elements
1678 i32 0 ;; Runtime Language
1679}
Jim Laskey14edc932006-03-14 18:08:46 +00001680
1681;;
1682;; Define the Red field.
1683;;
Devang Patel80ae3492009-08-28 23:24:31 +00001684!4 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001685 i32 524301, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001686 metadata !1, ;; Context
1687 metadata !"Red", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001688 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001689 i32 2, ;; Line number
1690 i64 32, ;; Size in bits
1691 i64 32, ;; Align in bits
1692 i64 0, ;; Offset in bits
1693 i32 0, ;; Flags
1694 metadata !5 ;; Derived From type
1695}
Jim Laskey14edc932006-03-14 18:08:46 +00001696
1697;;
1698;; Define the Green field.
1699;;
Devang Patel80ae3492009-08-28 23:24:31 +00001700!6 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001701 i32 524301, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001702 metadata !1, ;; Context
1703 metadata !"Green", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001704 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001705 i32 3, ;; Line number
1706 i64 32, ;; Size in bits
1707 i64 32, ;; Align in bits
1708 i64 32, ;; Offset in bits
1709 i32 0, ;; Flags
1710 metadata !5 ;; Derived From type
1711}
Jim Laskey14edc932006-03-14 18:08:46 +00001712
1713;;
1714;; Define the Blue field.
1715;;
Devang Patel80ae3492009-08-28 23:24:31 +00001716!7 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001717 i32 524301, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001718 metadata !1, ;; Context
1719 metadata !"Blue", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001720 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001721 i32 4, ;; Line number
1722 i64 32, ;; Size in bits
1723 i64 32, ;; Align in bits
1724 i64 64, ;; Offset in bits
1725 i32 0, ;; Flags
1726 metadata !5 ;; Derived From type
1727}
Jim Laskey14edc932006-03-14 18:08:46 +00001728
1729;;
1730;; Define the array of fields used by the composite type Color.
1731;;
Devang Patel80ae3492009-08-28 23:24:31 +00001732!3 = metadata !{metadata !4, metadata !6, metadata !7}
Jim Laskey14edc932006-03-14 18:08:46 +00001733</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001734</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001735
1736</div>
1737
1738<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001739<h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001740 <a name="ccxx_enumeration_types">C/C++ enumeration types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +00001741</h3>
Jim Laskey14edc932006-03-14 18:08:46 +00001742
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +00001743<div>
Jim Laskey14edc932006-03-14 18:08:46 +00001744
Misha Brukman39dcddf2008-12-16 02:54:22 +00001745<p>Given the following as an example of C/C++ enumeration type:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001746
Bill Wendlinge9353d72009-05-17 05:52:39 +00001747<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001748<pre>
1749enum Trees {
1750 Spruce = 100,
1751 Oak = 200,
1752 Maple = 300
1753};
1754</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001755</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001756
Misha Brukman39dcddf2008-12-16 02:54:22 +00001757<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +00001758
Bill Wendlinge9353d72009-05-17 05:52:39 +00001759<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +00001760<pre>
1761;;
1762;; Define composite type for enum Trees
1763;;
Devang Patel80ae3492009-08-28 23:24:31 +00001764!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +00001765 i32 524292, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +00001766 metadata !1, ;; Context
1767 metadata !"Trees", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +00001768 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +00001769 i32 1, ;; Line number
1770 i64 32, ;; Size in bits
1771 i64 32, ;; Align in bits
1772 i64 0, ;; Offset in bits
1773 i32 0, ;; Flags
1774 null, ;; Derived From type
1775 metadata !3, ;; Elements
1776 i32 0 ;; Runtime language
1777}
Devang Patel02aac922009-08-25 05:24:07 +00001778
Devang Patelf08e35d2009-08-26 05:01:18 +00001779;;
1780;; Define the array of enumerators used by composite type Trees.
1781;;
Devang Patel80ae3492009-08-28 23:24:31 +00001782!3 = metadata !{metadata !4, metadata !5, metadata !6}
1783
1784;;
1785;; Define Spruce enumerator.
1786;;
Devang Patel59445db2010-03-09 00:44:10 +00001787!4 = metadata !{i32 524328, metadata !"Spruce", i64 100}
Devang Patel80ae3492009-08-28 23:24:31 +00001788
1789;;
1790;; Define Oak enumerator.
1791;;
Devang Patel59445db2010-03-09 00:44:10 +00001792!5 = metadata !{i32 524328, metadata !"Oak", i64 200}
Devang Patel80ae3492009-08-28 23:24:31 +00001793
1794;;
1795;; Define Maple enumerator.
1796;;
Devang Patel59445db2010-03-09 00:44:10 +00001797!6 = metadata !{i32 524328, metadata !"Maple", i64 300}
Devang Patel80ae3492009-08-28 23:24:31 +00001798
Jim Laskey14edc932006-03-14 18:08:46 +00001799</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +00001800</div>
Jim Laskey14edc932006-03-14 18:08:46 +00001801
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1805
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1815 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
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