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gerrit-public.fairphone.software / platform / external / llvm / 901b5750b2af095bb0e359f4d2c3debef3ad57e6 / . / docs / SourceLevelDebugging.html
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Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6 <title>Source Level Debugging with LLVM</title>
7 <link rel="stylesheet" href="llvm.css" type="text/css">
8</head>
9<body>
10
11<div class="doc_title">Source Level Debugging with LLVM</div>
12
13<table class="layout" style="width:100%">
14 <tr class="layout">
15 <td class="left">
16<ul>
17 <li><a href="#introduction">Introduction</a>
18 <ol>
19 <li><a href="#phil">Philosophy behind LLVM debugging information</a></li>
20 <li><a href="#consumers">Debug information consumers</a></li>
21 <li><a href="#debugopt">Debugging optimized code</a></li>
22 </ol></li>
23 <li><a href="#format">Debugging information format</a>
24 <ol>
25 <li><a href="#debug_info_descriptors">Debug information descriptors</a>
26 <ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]27 <li><a href="#format_compile_units">Compile unit descriptors</a></li>
28 <li><a href="#format_global_variables">Global variable descriptors</a></li>
29 <li><a href="#format_subprograms">Subprogram descriptors</a></li>
30 <li><a href="#format_blocks">Block descriptors</a></li>
31 <li><a href="#format_basic_type">Basic type descriptors</a></li>
32 <li><a href="#format_derived_type">Derived type descriptors</a></li>
33 <li><a href="#format_composite_type">Composite type descriptors</a></li>
34 <li><a href="#format_subrange">Subrange descriptors</a></li>
35 <li><a href="#format_enumeration">Enumerator descriptors</a></li>
36 <li><a href="#format_variables">Local variables</a></li>
37 </ul></li>
38 <li><a href="#format_common_intrinsics">Debugger intrinsic functions</a>
39 <ul>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]40 <li><a href="#format_common_declare">llvm.dbg.declare</a></li>
Victor Hernandez128bf422010-01-11 22:53:48 +0000[diff] [blame]41 <li><a href="#format_common_value">llvm.dbg.value</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]42 </ul></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]43 </ol></li>
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]44 <li><a href="#format_common_lifetime">Object lifetimes and scoping</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]45 <li><a href="#ccxx_frontend">C/C++ front-end specific debug information</a>
46 <ol>
47 <li><a href="#ccxx_compile_units">C/C++ source file information</a></li>
48 <li><a href="#ccxx_global_variable">C/C++ global variable information</a></li>
49 <li><a href="#ccxx_subprogram">C/C++ function information</a></li>
50 <li><a href="#ccxx_basic_types">C/C++ basic types</a></li>
51 <li><a href="#ccxx_derived_types">C/C++ derived types</a></li>
52 <li><a href="#ccxx_composite_types">C/C++ struct/union types</a></li>
53 <li><a href="#ccxx_enumeration_types">C/C++ enumeration types</a></li>
54 </ol></li>
55</ul>
56</td>
57<td class="right">
58<img src="img/venusflytrap.jpg" alt="A leafy and green bug eater" width="247"
59height="369">
60</td>
61</tr></table>
62
63<div class="doc_author">
64 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
65 and <a href="mailto:jlaskey@mac.com">Jim Laskey</a></p>
66</div>
67
68
69<!-- *********************************************************************** -->
70<div class="doc_section"><a name="introduction">Introduction</a></div>
71<!-- *********************************************************************** -->
72
73<div class="doc_text">
74
75<p>This document is the central repository for all information pertaining to
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]76 debug information in LLVM. It describes the <a href="#format">actual format
77 that the LLVM debug information</a> takes, which is useful for those
78 interested in creating front-ends or dealing directly with the information.
Chris Lattner990e7652009-07-18 21:47:15 +0000[diff] [blame]79 Further, this document provides specific examples of what debug information
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]80 for C/C++.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]81
82</div>
83
84<!-- ======================================================================= -->
85<div class="doc_subsection">
86 <a name="phil">Philosophy behind LLVM debugging information</a>
87</div>
88
89<div class="doc_text">
90
91<p>The idea of the LLVM debugging information is to capture how the important
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]92 pieces of the source-language's Abstract Syntax Tree map onto LLVM code.
93 Several design aspects have shaped the solution that appears here. The
94 important ones are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]95
96<ul>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]97 <li>Debugging information should have very little impact on the rest of the
98 compiler. No transformations, analyses, or code generators should need to
99 be modified because of debugging information.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]100
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]101 <li>LLVM optimizations should interact in <a href="#debugopt">well-defined and
102 easily described ways</a> with the debugging information.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]103
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]104 <li>Because LLVM is designed to support arbitrary programming languages,
105 LLVM-to-LLVM tools should not need to know anything about the semantics of
106 the source-level-language.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]107
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]108 <li>Source-level languages are often <b>widely</b> different from one another.
109 LLVM should not put any restrictions of the flavor of the source-language,
110 and the debugging information should work with any language.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]111
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]112 <li>With code generator support, it should be possible to use an LLVM compiler
113 to compile a program to native machine code and standard debugging
114 formats. This allows compatibility with traditional machine-code level
115 debuggers, like GDB or DBX.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]116</ul>
117
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]118<p>The approach used by the LLVM implementation is to use a small set
119 of <a href="#format_common_intrinsics">intrinsic functions</a> to define a
120 mapping between LLVM program objects and the source-level objects. The
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]121 description of the source-level program is maintained in LLVM metadata
122 in an <a href="#ccxx_frontend">implementation-defined format</a>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]123 (the C/C++ front-end currently uses working draft 7 of
124 the <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3
125 standard</a>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]126
127<p>When a program is being debugged, a debugger interacts with the user and
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]128 turns the stored debug information into source-language specific information.
129 As such, a debugger must be aware of the source-language, and is thus tied to
130 a specific language or family of languages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]131
132</div>
133
134<!-- ======================================================================= -->
135<div class="doc_subsection">
136 <a name="consumers">Debug information consumers</a>
137</div>
138
139<div class="doc_text">
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]140
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]141<p>The role of debug information is to provide meta information normally
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]142 stripped away during the compilation process. This meta information provides
143 an LLVM user a relationship between generated code and the original program
144 source code.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]145
146<p>Currently, debug information is consumed by the DwarfWriter to produce dwarf
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]147 information used by the gdb debugger. Other targets could use the same
148 information to produce stabs or other debug forms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]149
150<p>It would also be reasonable to use debug information to feed profiling tools
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]151 for analysis of generated code, or, tools for reconstructing the original
152 source from generated code.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]153
154<p>TODO - expound a bit more.</p>
155
156</div>
157
158<!-- ======================================================================= -->
159<div class="doc_subsection">
160 <a name="debugopt">Debugging optimized code</a>
161</div>
162
163<div class="doc_text">
164
165<p>An extremely high priority of LLVM debugging information is to make it
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]166 interact well with optimizations and analysis. In particular, the LLVM debug
167 information provides the following guarantees:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]168
169<ul>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]170 <li>LLVM debug information <b>always provides information to accurately read
171 the source-level state of the program</b>, regardless of which LLVM
172 optimizations have been run, and without any modification to the
173 optimizations themselves. However, some optimizations may impact the
174 ability to modify the current state of the program with a debugger, such
175 as setting program variables, or calling functions that have been
176 deleted.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]177
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]178 <li>LLVM optimizations gracefully interact with debugging information. If
179 they are not aware of debug information, they are automatically disabled
180 as necessary in the cases that would invalidate the debug info. This
181 retains the LLVM features, making it easy to write new
182 transformations.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]183
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]184 <li>As desired, LLVM optimizations can be upgraded to be aware of the LLVM
185 debugging information, allowing them to update the debugging information
186 as they perform aggressive optimizations. This means that, with effort,
187 the LLVM optimizers could optimize debug code just as well as non-debug
188 code.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]189
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]190 <li>LLVM debug information does not prevent many important optimizations from
191 happening (for example inlining, basic block reordering/merging/cleanup,
192 tail duplication, etc), further reducing the amount of the compiler that
193 eventually is "aware" of debugging information.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]194
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]195 <li>LLVM debug information is automatically optimized along with the rest of
196 the program, using existing facilities. For example, duplicate
197 information is automatically merged by the linker, and unused information
198 is automatically removed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]199</ul>
200
201<p>Basically, the debug information allows you to compile a program with
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]202 "<tt>-O0 -g</tt>" and get full debug information, allowing you to arbitrarily
203 modify the program as it executes from a debugger. Compiling a program with
204 "<tt>-O3 -g</tt>" gives you full debug information that is always available
205 and accurate for reading (e.g., you get accurate stack traces despite tail
206 call elimination and inlining), but you might lose the ability to modify the
207 program and call functions where were optimized out of the program, or
208 inlined away completely.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]209
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]210<p><a href="TestingGuide.html#quicktestsuite">LLVM test suite</a> provides a
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]211 framework to test optimizer's handling of debugging information. It can be
212 run like this:</p>
Devang Patel7717e542008-11-21 19:35:57 +0000[diff] [blame]213
214<div class="doc_code">
215<pre>
216% cd llvm/projects/test-suite/MultiSource/Benchmarks # or some other level
217% make TEST=dbgopt
218</pre>
219</div>
220
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]221<p>This will test impact of debugging information on optimization passes. If
222 debugging information influences optimization passes then it will be reported
223 as a failure. See <a href="TestingGuide.html">TestingGuide</a> for more
224 information on LLVM test infrastructure and how to run various tests.</p>
Devang Patel7717e542008-11-21 19:35:57 +0000[diff] [blame]225
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]226</div>
227
228<!-- *********************************************************************** -->
229<div class="doc_section">
230 <a name="format">Debugging information format</a>
231</div>
232<!-- *********************************************************************** -->
233
234<div class="doc_text">
235
236<p>LLVM debugging information has been carefully designed to make it possible
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]237 for the optimizer to optimize the program and debugging information without
238 necessarily having to know anything about debugging information. In
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]239 particular, te use of metadadta avoids duplicated dubgging information from
240 the beginning, and the global dead code elimination pass automatically
241 deletes debugging information for a function if it decides to delete the
242 function. </p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]243
244<p>To do this, most of the debugging information (descriptors for types,
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]245 variables, functions, source files, etc) is inserted by the language
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]246 front-end in the form of LLVM metadata. </p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]247
248<p>Debug information is designed to be agnostic about the target debugger and
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]249 debugging information representation (e.g. DWARF/Stabs/etc). It uses a
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]250 generic pass to decode the information that represents variables, types,
251 functions, namespaces, etc: this allows for arbitrary source-language
252 semantics and type-systems to be used, as long as there is a module
253 written for the target debugger to interpret the information. </p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]254
255<p>To provide basic functionality, the LLVM debugger does have to make some
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]256 assumptions about the source-level language being debugged, though it keeps
257 these to a minimum. The only common features that the LLVM debugger assumes
258 exist are <a href="#format_compile_units">source files</a>,
259 and <a href="#format_global_variables">program objects</a>. These abstract
260 objects are used by a debugger to form stack traces, show information about
261 local variables, etc.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]262
263<p>This section of the documentation first describes the representation aspects
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]264 common to any source-language. The <a href="#ccxx_frontend">next section</a>
265 describes the data layout conventions used by the C and C++ front-ends.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]266
267</div>
268
269<!-- ======================================================================= -->
270<div class="doc_subsection">
271 <a name="debug_info_descriptors">Debug information descriptors</a>
272</div>
273
274<div class="doc_text">
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]275
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]276<p>In consideration of the complexity and volume of debug information, LLVM
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]277 provides a specification for well formed debug descriptors. </p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]278
279<p>Consumers of LLVM debug information expect the descriptors for program
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]280 objects to start in a canonical format, but the descriptors can include
281 additional information appended at the end that is source-language
282 specific. All LLVM debugging information is versioned, allowing backwards
283 compatibility in the case that the core structures need to change in some
284 way. Also, all debugging information objects start with a tag to indicate
285 what type of object it is. The source-language is allowed to define its own
286 objects, by using unreserved tag numbers. We recommend using with tags in
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]287 the range 0x1000 through 0x2000 (there is a defined enum DW_TAG_user_base =
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]288 0x1000.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]289
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]290<p>The fields of debug descriptors used internally by LLVM
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]291 are restricted to only the simple data types <tt>int</tt>, <tt>uint</tt>,
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]292 <tt>bool</tt>, <tt>float</tt>, <tt>double</tt>, <tt>mdstring</tt> and
293 <tt>mdnode</tt>. </p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]294
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]295<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]296<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]297!1 = metadata !{
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]298 uint, ;; A tag
299 ...
300}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]301</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]302</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]303
304<p><a name="LLVMDebugVersion">The first field of a descriptor is always an
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]305 <tt>uint</tt> containing a tag value identifying the content of the
306 descriptor. The remaining fields are specific to the descriptor. The values
307 of tags are loosely bound to the tag values of DWARF information entries.
308 However, that does not restrict the use of the information supplied to DWARF
309 targets. To facilitate versioning of debug information, the tag is augmented
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]310 with the current debug version (LLVMDebugVersion = 7 << 16 or 0x70000 or
311 458752.)</a></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]312
313<p>The details of the various descriptors follow.</p>
314
315</div>
316
317<!-- ======================================================================= -->
318<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]319 <a name="format_compile_units">Compile unit descriptors</a>
320</div>
321
322<div class="doc_text">
323
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]324<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]325<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]326!0 = metadata !{
327 i32, ;; Tag = 17 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
328 ;; (DW_TAG_compile_unit)
329 i32, ;; Unused field.
330 i32, ;; DWARF language identifier (ex. DW_LANG_C89)
331 metadata, ;; Source file name
332 metadata, ;; Source file directory (includes trailing slash)
333 metadata ;; Producer (ex. "4.0.1 LLVM (LLVM research group)")
334 i1, ;; True if this is a main compile unit.
335 i1, ;; True if this is optimized.
336 metadata, ;; Flags
337 i32 ;; Runtime version
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]338}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]339</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]340</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]341
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]342<p>These descriptors contain a source language ID for the file (we use the DWARF
343 3.0 ID numbers, such as <tt>DW_LANG_C89</tt>, <tt>DW_LANG_C_plus_plus</tt>,
344 <tt>DW_LANG_Cobol74</tt>, etc), three strings describing the filename,
345 working directory of the compiler, and an identifier string for the compiler
346 that produced it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]347
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]348<p>Compile unit descriptors provide the root context for objects declared in a
349 specific source file. Global variables and top level functions would be
350 defined using this context. Compile unit descriptors also provide context
351 for source line correspondence.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]352
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]353<p>Each input file is encoded as a separate compile unit in LLVM debugging
354 information output. However, many target specific tool chains prefer to
355 encode only one compile unit in an object file. In this situation, the LLVM
356 code generator will include debugging information entities in the compile
357 unit that is marked as main compile unit. The code generator accepts maximum
358 one main compile unit per module. If a module does not contain any main
359 compile unit then the code generator will emit multiple compile units in the
360 output object file.</p>
361
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]362</div>
363
364<!-- ======================================================================= -->
365<div class="doc_subsubsection">
366 <a name="format_global_variables">Global variable descriptors</a>
367</div>
368
369<div class="doc_text">
370
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]371<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]372<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]373!1 = metadata !{
374 i32, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
375 ;; (DW_TAG_variable)
376 i32, ;; Unused field.
377 metadata, ;; Reference to context descriptor
378 metadata, ;; Name
379 metadata, ;; Display name (fully qualified C++ name)
380 metadata, ;; MIPS linkage name (for C++)
381 metadata, ;; Reference to compile unit where defined
382 i32, ;; Line number where defined
383 metadata, ;; Reference to type descriptor
384 i1, ;; True if the global is local to compile unit (static)
385 i1, ;; True if the global is defined in the compile unit (not extern)
386 { }* ;; Reference to the global variable
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]387}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]388</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]389</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]390
391<p>These descriptors provide debug information about globals variables. The
392provide details such as name, type and where the variable is defined.</p>
393
394</div>
395
396<!-- ======================================================================= -->
397<div class="doc_subsubsection">
398 <a name="format_subprograms">Subprogram descriptors</a>
399</div>
400
401<div class="doc_text">
402
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]403<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]404<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]405!2 = metadata !{
406 i32, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
407 ;; (DW_TAG_subprogram)
408 i32, ;; Unused field.
409 metadata, ;; Reference to context descriptor
410 metadata, ;; Name
411 metadata, ;; Display name (fully qualified C++ name)
412 metadata, ;; MIPS linkage name (for C++)
413 metadata, ;; Reference to compile unit where defined
414 i32, ;; Line number where defined
415 metadata, ;; Reference to type descriptor
416 i1, ;; True if the global is local to compile unit (static)
417 i1 ;; True if the global is defined in the compile unit (not extern)
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]418}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]419</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]420</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]421
422<p>These descriptors provide debug information about functions, methods and
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]423 subprograms. They provide details such as name, return types and the source
424 location where the subprogram is defined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]425
426</div>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]427
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]428<!-- ======================================================================= -->
429<div class="doc_subsubsection">
430 <a name="format_blocks">Block descriptors</a>
431</div>
432
433<div class="doc_text">
434
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]435<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]436<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]437!3 = metadata !{
438 i32, ;; Tag = 13 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
439 metadata ;; Reference to context descriptor
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]440}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]441</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]442</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]443
444<p>These descriptors provide debug information about nested blocks within a
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]445 subprogram. The array of member descriptors is used to define local
446 variables and deeper nested blocks.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]447
448</div>
449
450<!-- ======================================================================= -->
451<div class="doc_subsubsection">
452 <a name="format_basic_type">Basic type descriptors</a>
453</div>
454
455<div class="doc_text">
456
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]457<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]459!4 = metadata !{
460 i32, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
461 ;; (DW_TAG_base_type)
462 metadata, ;; Reference to context (typically a compile unit)
463 metadata, ;; Name (may be "" for anonymous types)
464 metadata, ;; Reference to compile unit where defined (may be NULL)
465 i32, ;; Line number where defined (may be 0)
466 i64, ;; Size in bits
467 i64, ;; Alignment in bits
468 i64, ;; Offset in bits
469 i32, ;; Flags
470 i32 ;; DWARF type encoding
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]471}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]472</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]473</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]474
475<p>These descriptors define primitive types used in the code. Example int, bool
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]476 and float. The context provides the scope of the type, which is usually the
477 top level. Since basic types are not usually user defined the compile unit
478 and line number can be left as NULL and 0. The size, alignment and offset
479 are expressed in bits and can be 64 bit values. The alignment is used to
480 round the offset when embedded in a
481 <a href="#format_composite_type">composite type</a> (example to keep float
482 doubles on 64 bit boundaries.) The offset is the bit offset if embedded in
483 a <a href="#format_composite_type">composite type</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]484
485<p>The type encoding provides the details of the type. The values are typically
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]486 one of the following:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]487
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]488<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]489<pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]490DW_ATE_address = 1
491DW_ATE_boolean = 2
492DW_ATE_float = 4
493DW_ATE_signed = 5
494DW_ATE_signed_char = 6
495DW_ATE_unsigned = 7
496DW_ATE_unsigned_char = 8
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]497</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]498</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]499
500</div>
501
502<!-- ======================================================================= -->
503<div class="doc_subsubsection">
504 <a name="format_derived_type">Derived type descriptors</a>
505</div>
506
507<div class="doc_text">
508
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]509<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]510<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]511!5 = metadata !{
512 i32, ;; Tag (see below)
513 metadata, ;; Reference to context
514 metadata, ;; Name (may be "" for anonymous types)
515 metadata, ;; Reference to compile unit where defined (may be NULL)
516 i32, ;; Line number where defined (may be 0)
517 i32, ;; Size in bits
518 i32, ;; Alignment in bits
519 i32, ;; Offset in bits
520 metadata ;; Reference to type derived from
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]521}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]522</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]523</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]524
525<p>These descriptors are used to define types derived from other types. The
526value of the tag varies depending on the meaning. The following are possible
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]527tag values:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]528
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]529<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]530<pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]531DW_TAG_formal_parameter = 5
532DW_TAG_member = 13
533DW_TAG_pointer_type = 15
534DW_TAG_reference_type = 16
535DW_TAG_typedef = 22
536DW_TAG_const_type = 38
537DW_TAG_volatile_type = 53
538DW_TAG_restrict_type = 55
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]539</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]540</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]541
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]542<p><tt>DW_TAG_member</tt> is used to define a member of
543 a <a href="#format_composite_type">composite type</a>
544 or <a href="#format_subprograms">subprogram</a>. The type of the member is
545 the <a href="#format_derived_type">derived
546 type</a>. <tt>DW_TAG_formal_parameter</tt> is used to define a member which
547 is a formal argument of a subprogram.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]548
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]549<p><tt>DW_TAG_typedef</tt> is used to provide a name for the derived type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]550
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]551<p><tt>DW_TAG_pointer_type</tt>,<tt>DW_TAG_reference_type</tt>,
552 <tt>DW_TAG_const_type</tt>, <tt>DW_TAG_volatile_type</tt>
553 and <tt>DW_TAG_restrict_type</tt> are used to qualify
554 the <a href="#format_derived_type">derived type</a>. </p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]555
556<p><a href="#format_derived_type">Derived type</a> location can be determined
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]557 from the compile unit and line number. The size, alignment and offset are
558 expressed in bits and can be 64 bit values. The alignment is used to round
559 the offset when embedded in a <a href="#format_composite_type">composite
560 type</a> (example to keep float doubles on 64 bit boundaries.) The offset is
561 the bit offset if embedded in a <a href="#format_composite_type">composite
562 type</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]563
564<p>Note that the <tt>void *</tt> type is expressed as a
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]565 <tt>llvm.dbg.derivedtype.type</tt> with tag of <tt>DW_TAG_pointer_type</tt>
566 and <tt>NULL</tt> derived type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]567
568</div>
569
570<!-- ======================================================================= -->
571<div class="doc_subsubsection">
572 <a name="format_composite_type">Composite type descriptors</a>
573</div>
574
575<div class="doc_text">
576
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]577<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]578<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]579!6 = metadata !{
580 i32, ;; Tag (see below)
581 metadata, ;; Reference to context
582 metadata, ;; Name (may be "" for anonymous types)
583 metadata, ;; Reference to compile unit where defined (may be NULL)
584 i32, ;; Line number where defined (may be 0)
585 i64, ;; Size in bits
586 i64, ;; Alignment in bits
587 i64, ;; Offset in bits
588 i32, ;; Flags
589 metadata, ;; Reference to type derived from
590 metadata, ;; Reference to array of member descriptors
591 i32 ;; Runtime languages
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]592}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]593</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]594</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]595
596<p>These descriptors are used to define types that are composed of 0 or more
597elements. The value of the tag varies depending on the meaning. The following
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]598are possible tag values:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]599
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]600<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]601<pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]602DW_TAG_array_type = 1
603DW_TAG_enumeration_type = 4
604DW_TAG_structure_type = 19
605DW_TAG_union_type = 23
606DW_TAG_vector_type = 259
Bruno Cardoso Lopes7ad46092009-05-29 17:08:57 +0000[diff] [blame]607DW_TAG_subroutine_type = 21
608DW_TAG_inheritance = 28
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]609</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]610</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]611
612<p>The vector flag indicates that an array type is a native packed vector.</p>
613
614<p>The members of array types (tag = <tt>DW_TAG_array_type</tt>) or vector types
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]615 (tag = <tt>DW_TAG_vector_type</tt>) are <a href="#format_subrange">subrange
616 descriptors</a>, each representing the range of subscripts at that level of
617 indexing.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]618
619<p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]620 <a href="#format_enumeration">enumerator descriptors</a>, each representing
621 the definition of enumeration value for the set.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]622
623<p>The members of structure (tag = <tt>DW_TAG_structure_type</tt>) or union (tag
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]624 = <tt>DW_TAG_union_type</tt>) types are any one of
625 the <a href="#format_basic_type">basic</a>,
626 <a href="#format_derived_type">derived</a>
627 or <a href="#format_composite_type">composite</a> type descriptors, each
628 representing a field member of the structure or union.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]629
630<p>For C++ classes (tag = <tt>DW_TAG_structure_type</tt>), member descriptors
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]631 provide information about base classes, static members and member
632 functions. If a member is a <a href="#format_derived_type">derived type
633 descriptor</a> and has a tag of <tt>DW_TAG_inheritance</tt>, then the type
634 represents a base class. If the member of is
635 a <a href="#format_global_variables">global variable descriptor</a> then it
636 represents a static member. And, if the member is
637 a <a href="#format_subprograms">subprogram descriptor</a> then it represents
638 a member function. For static members and member
639 functions, <tt>getName()</tt> returns the members link or the C++ mangled
640 name. <tt>getDisplayName()</tt> the simplied version of the name.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]641
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]642<p>The first member of subroutine (tag = <tt>DW_TAG_subroutine_type</tt>) type
643 elements is the return type for the subroutine. The remaining elements are
644 the formal arguments to the subroutine.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]645
646<p><a href="#format_composite_type">Composite type</a> location can be
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]647 determined from the compile unit and line number. The size, alignment and
648 offset are expressed in bits and can be 64 bit values. The alignment is used
649 to round the offset when embedded in
650 a <a href="#format_composite_type">composite type</a> (as an example, to keep
651 float doubles on 64 bit boundaries.) The offset is the bit offset if embedded
652 in a <a href="#format_composite_type">composite type</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]653
654</div>
655
656<!-- ======================================================================= -->
657<div class="doc_subsubsection">
658 <a name="format_subrange">Subrange descriptors</a>
659</div>
660
661<div class="doc_text">
662
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]663<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]664<pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]665%<a href="#format_subrange">llvm.dbg.subrange.type</a> = type {
666 i32, ;; Tag = 33 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subrange_type)
667 i64, ;; Low value
668 i64 ;; High value
669}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]670</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]671</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]672
673<p>These descriptors are used to define ranges of array subscripts for an array
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]674 <a href="#format_composite_type">composite type</a>. The low value defines
675 the lower bounds typically zero for C/C++. The high value is the upper
676 bounds. Values are 64 bit. High - low + 1 is the size of the array. If low
677 == high the array will be unbounded.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]678
679</div>
680
681<!-- ======================================================================= -->
682<div class="doc_subsubsection">
683 <a name="format_enumeration">Enumerator descriptors</a>
684</div>
685
686<div class="doc_text">
687
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]688<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]689<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]690!6 = metadata !{
691 i32, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
692 ;; (DW_TAG_enumerator)
693 metadata, ;; Name
694 i64 ;; Value
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]695}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]696</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]697</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]698
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]699<p>These descriptors are used to define members of an
700 enumeration <a href="#format_composite_type">composite type</a>, it
701 associates the name to the value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]702
703</div>
704
705<!-- ======================================================================= -->
706<div class="doc_subsubsection">
707 <a name="format_variables">Local variables</a>
708</div>
709
710<div class="doc_text">
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]711
712<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]713<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]714!7 = metadata !{
715 i32, ;; Tag (see below)
716 metadata, ;; Context
717 metadata, ;; Name
718 metadata, ;; Reference to compile unit where defined
719 i32, ;; Line number where defined
720 metadata ;; Type descriptor
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]721}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]722</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]723</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]724
725<p>These descriptors are used to define variables local to a sub program. The
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]726 value of the tag depends on the usage of the variable:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]727
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]728<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]729<pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]730DW_TAG_auto_variable = 256
731DW_TAG_arg_variable = 257
732DW_TAG_return_variable = 258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]733</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]734</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]735
736<p>An auto variable is any variable declared in the body of the function. An
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]737 argument variable is any variable that appears as a formal argument to the
738 function. A return variable is used to track the result of a function and
739 has no source correspondent.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]740
741<p>The context is either the subprogram or block where the variable is defined.
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]742 Name the source variable name. Compile unit and line indicate where the
743 variable was defined. Type descriptor defines the declared type of the
744 variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]745
746</div>
747
748<!-- ======================================================================= -->
749<div class="doc_subsection">
750 <a name="format_common_intrinsics">Debugger intrinsic functions</a>
751</div>
752
753<div class="doc_text">
754
755<p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]756 provide debug information at various points in generated code.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]757
758</div>
759
760<!-- ======================================================================= -->
761<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]762 <a name="format_common_declare">llvm.dbg.declare</a>
763</div>
764
765<div class="doc_text">
766<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]767 void %<a href="#format_common_declare">llvm.dbg.declare</a>( { } *, metadata )
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]768</pre>
769
770<p>This intrinsic provides information about a local element (ex. variable.) The
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]771 first argument is the alloca for the variable, cast to a <tt>{ }*</tt>. The
772 second argument is
773 the <tt>%<a href="#format_variables">llvm.dbg.variable</a></tt> containing
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]774 the description of the variable. </p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]775
776</div>
777
778<!-- ======================================================================= -->
Victor Hernandez128bf422010-01-11 22:53:48 +0000[diff] [blame]779<div class="doc_subsubsection">
780 <a name="format_common_value">llvm.dbg.value</a>
781</div>
782
783<div class="doc_text">
784<pre>
785 void %<a href="#format_common_value">llvm.dbg.value</a>( metadata, i64, metadata )
786</pre>
787
788<p>This intrinsic provides information when a user source variable is set to a
789 new value. The first argument is the new value (wrapped as metadata). The
790 second argument is the offset in the user source variable where the new value
791 is written. The third argument is
792 the <tt>%<a href="#format_variables">llvm.dbg.variable</a></tt> containing
793 the description of the user source variable. </p>
794
795</div>
796
797<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]798<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]799 <a name="format_common_lifetime">Object lifetimes and scoping</a>
800</div>
801
802<div class="doc_text">
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]803<p>In many languages, the local variables in functions can have their lifetimes
804 or scopes limited to a subset of a function. In the C family of languages,
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]805 for example, variables are only live (readable and writable) within the
806 source block that they are defined in. In functional languages, values are
807 only readable after they have been defined. Though this is a very obvious
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]808 concept, it is non-trivial to model in LLVM, because it has no notion of
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]809 scoping in this sense, and does not want to be tied to a language's scoping
810 rules.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]811
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]812<p>In order to handle this, the LLVM debug format uses the metadata attached to
813 llvm instructions to encode line nuber and scoping information. Consider the
814 following C fragment, for example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]815
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]816<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]817<pre>
8181. void foo() {
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]8192. int X = 21;
8203. int Y = 22;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]8214. {
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]8225. int Z = 23;
8236. Z = X;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]8247. }
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]8258. X = Y;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]8269. }
827</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]828</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]829
830<p>Compiled to LLVM, this function would be represented like this:</p>
831
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]832<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]833<pre>
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]834define void @foo() nounwind ssp {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]835entry:
Bill Wendling05837cd2009-12-01 00:59:58 +0000[diff] [blame]836 %X = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
837 %Y = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
838 %Z = alloca i32, align 4 ; &lt;i32*&gt; [#uses=3]
839 %0 = bitcast i32* %X to { }* ; &lt;{ }*&gt; [#uses=1]
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]840 call void @llvm.dbg.declare({ }* %0, metadata !0), !dbg !7
841 store i32 21, i32* %X, !dbg !8
Bill Wendling05837cd2009-12-01 00:59:58 +0000[diff] [blame]842 %1 = bitcast i32* %Y to { }* ; &lt;{ }*&gt; [#uses=1]
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]843 call void @llvm.dbg.declare({ }* %1, metadata !9), !dbg !10
844 store i32 22, i32* %Y, !dbg !11
Bill Wendling05837cd2009-12-01 00:59:58 +0000[diff] [blame]845 %2 = bitcast i32* %Z to { }* ; &lt;{ }*&gt; [#uses=1]
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]846 call void @llvm.dbg.declare({ }* %2, metadata !12), !dbg !14
847 store i32 23, i32* %Z, !dbg !15
Bill Wendling05837cd2009-12-01 00:59:58 +0000[diff] [blame]848 %tmp = load i32* %X, !dbg !16 ; &lt;i32&gt; [#uses=1]
849 %tmp1 = load i32* %Y, !dbg !16 ; &lt;i32&gt; [#uses=1]
850 %add = add nsw i32 %tmp, %tmp1, !dbg !16 ; &lt;i32&gt; [#uses=1]
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]851 store i32 %add, i32* %Z, !dbg !16
Bill Wendling05837cd2009-12-01 00:59:58 +0000[diff] [blame]852 %tmp2 = load i32* %Y, !dbg !17 ; &lt;i32&gt; [#uses=1]
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]853 store i32 %tmp2, i32* %X, !dbg !17
854 ret void, !dbg !18
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]855}
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]856
857declare void @llvm.dbg.declare({ }*, metadata) nounwind readnone
858
859!0 = metadata !{i32 459008, metadata !1, metadata !"X",
860 metadata !3, i32 2, metadata !6}; [ DW_TAG_auto_variable ]
861!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
862!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo", metadata !"foo",
863 metadata !"foo", metadata !3, i32 1, metadata !4,
864 i1 false, i1 true}; [DW_TAG_subprogram ]
865!3 = metadata !{i32 458769, i32 0, i32 12, metadata !"foo.c",
866 metadata !"/private/tmp", metadata !"clang 1.1", i1 true,
867 i1 false, metadata !"", i32 0}; [DW_TAG_compile_unit ]
868!4 = metadata !{i32 458773, metadata !3, metadata !"", null, i32 0, i64 0, i64 0,
869 i64 0, i32 0, null, metadata !5, i32 0}; [DW_TAG_subroutine_type ]
870!5 = metadata !{null}
871!6 = metadata !{i32 458788, metadata !3, metadata !"int", metadata !3, i32 0,
872 i64 32, i64 32, i64 0, i32 0, i32 5}; [DW_TAG_base_type ]
873!7 = metadata !{i32 2, i32 7, metadata !1, null}
874!8 = metadata !{i32 2, i32 3, metadata !1, null}
875!9 = metadata !{i32 459008, metadata !1, metadata !"Y", metadata !3, i32 3,
876 metadata !6}; [ DW_TAG_auto_variable ]
877!10 = metadata !{i32 3, i32 7, metadata !1, null}
878!11 = metadata !{i32 3, i32 3, metadata !1, null}
879!12 = metadata !{i32 459008, metadata !13, metadata !"Z", metadata !3, i32 5,
880 metadata !6}; [ DW_TAG_auto_variable ]
881!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
882!14 = metadata !{i32 5, i32 9, metadata !13, null}
883!15 = metadata !{i32 5, i32 5, metadata !13, null}
884!16 = metadata !{i32 6, i32 5, metadata !13, null}
885!17 = metadata !{i32 8, i32 3, metadata !1, null}
886!18 = metadata !{i32 9, i32 1, metadata !2, null}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]887</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]888</div>
889
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]890<p>This example illustrates a few important details about LLVM debugging
891 information. In particular, it shows how the <tt>llvm.dbg.declare</tt>
892 intrinsic and location information, which are attached to an instruction,
893 are applied together to allow a debugger to analyze the relationship between
894 statements, variable definitions, and the code used to implement the
895 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]896
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]897<div class="doc_code">
Bill Wendling05837cd2009-12-01 00:59:58 +0000[diff] [blame]898<pre>
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]899call void @llvm.dbg.declare({ }* %0, metadata !0), !dbg !7
900</pre>
901</div>
902
903<p>The first intrinsic
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]904 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]905 encodes debugging information for the variable <tt>X</tt>. The metadata
906 <tt>!dbg !7</tt> attached to the intrinsic provides scope information for the
907 variable <tt>X</tt>.</p>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]908
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]909<div class="doc_code">
910<pre>
911!7 = metadata !{i32 2, i32 7, metadata !1, null}
912!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
913!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo",
914 metadata !"foo", metadata !"foo", metadata !3, i32 1,
915 metadata !4, i1 false, i1 true}; [DW_TAG_subprogram ]
916</pre>
917</div>
918
919<p>Here <tt>!7</tt> is metadata providing location information. It has four
920 fields: line number, column number, scope, and original scope. The original
921 scope represents inline location if this instruction is inlined inside a
922 caller, and is null otherwise. In this example, scope is encoded by
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]923 <tt>!1</tt>. <tt>!1</tt> represents a lexical block inside the scope
924 <tt>!2</tt>, where <tt>!2</tt> is a
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]925 <a href="#format_subprograms">subprogram descriptor</a>. This way the
926 location information attached to the intrinsics indicates that the
927 variable <tt>X</tt> is declared at line number 2 at a function level scope in
928 function <tt>foo</tt>.</p>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]929
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]930<p>Now lets take another example.</p>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]931
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]932<div class="doc_code">
Bill Wendling05837cd2009-12-01 00:59:58 +0000[diff] [blame]933<pre>
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]934call void @llvm.dbg.declare({ }* %2, metadata !12), !dbg !14
935</pre>
936</div>
937
938<p>The second intrinsic
Devang Patelcacef072009-11-25 23:28:01 +0000[diff] [blame]939 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]940 encodes debugging information for variable <tt>Z</tt>. The metadata
941 <tt>!dbg !14</tt> attached to the intrinsic provides scope information for
942 the variable <tt>Z</tt>.</p>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]943
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]944<div class="doc_code">
945<pre>
946!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
947!14 = metadata !{i32 5, i32 9, metadata !13, null}
948</pre>
949</div>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]950
Bill Wendlingd90060e2009-12-01 00:53:11 +0000[diff] [blame]951<p>Here <tt>!14</tt> indicates that <tt>Z</tt> is declaread at line number 5 and
952 column number 9 inside of lexical scope <tt>!13</tt>. The lexical scope
953 itself resides inside of lexical scope <tt>!1</tt> described above.</p>
954
955<p>The scope information attached with each instruction provides a
956 straightforward way to find instructions covered by a scope.</p>
957
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]958</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]959
960<!-- *********************************************************************** -->
961<div class="doc_section">
962 <a name="ccxx_frontend">C/C++ front-end specific debug information</a>
963</div>
964<!-- *********************************************************************** -->
965
966<div class="doc_text">
967
968<p>The C and C++ front-ends represent information about the program in a format
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]969 that is effectively identical
970 to <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3.0</a> in
971 terms of information content. This allows code generators to trivially
972 support native debuggers by generating standard dwarf information, and
973 contains enough information for non-dwarf targets to translate it as
974 needed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]975
976<p>This section describes the forms used to represent C and C++ programs. Other
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]977 languages could pattern themselves after this (which itself is tuned to
978 representing programs in the same way that DWARF 3 does), or they could
979 choose to provide completely different forms if they don't fit into the DWARF
980 model. As support for debugging information gets added to the various LLVM
981 source-language front-ends, the information used should be documented
982 here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]983
984<p>The following sections provide examples of various C/C++ constructs and the
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]985 debug information that would best describe those constructs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]986
987</div>
988
989<!-- ======================================================================= -->
990<div class="doc_subsection">
991 <a name="ccxx_compile_units">C/C++ source file information</a>
992</div>
993
994<div class="doc_text">
995
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]996<p>Given the source files <tt>MySource.cpp</tt> and <tt>MyHeader.h</tt> located
997 in the directory <tt>/Users/mine/sources</tt>, the following code:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]998
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]999<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1000<pre>
1001#include "MyHeader.h"
1002
1003int main(int argc, char *argv[]) {
1004 return 0;
1005}
1006</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1007</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1008
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1009<p>a C/C++ front-end would generate the following descriptors:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1010
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1011<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1012<pre>
1013...
1014;;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1015;; Define the compile unit for the source file "/Users/mine/sources/MySource.cpp".
1016;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1017!3 = metadata !{
1018 i32 458769, ;; Tag
1019 i32 0, ;; Unused
1020 i32 4, ;; Language Id
1021 metadata !"MySource.cpp",
1022 metadata !"/Users/mine/sources",
1023 metadata !"4.2.1 (Based on Apple Inc. build 5649) (LLVM build 00)",
1024 i1 true, ;; Main Compile Unit
1025 i1 false, ;; Optimized compile unit
1026 metadata !"", ;; Compiler flags
1027 i32 0} ;; Runtime version
1028
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1029;;
1030;; Define the compile unit for the header file "/Users/mine/sources/MyHeader.h".
1031;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1032!1 = metadata !{
1033 i32 458769, ;; Tag
1034 i32 0, ;; Unused
1035 i32 4, ;; Language Id
1036 metadata !"MyHeader.h",
1037 metadata !"/Users/mine/sources",
1038 metadata !"4.2.1 (Based on Apple Inc. build 5649) (LLVM build 00)",
1039 i1 false, ;; Main Compile Unit
1040 i1 false, ;; Optimized compile unit
1041 metadata !"", ;; Compiler flags
1042 i32 0} ;; Runtime version
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1044...
1045</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1046</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1047
1048</div>
1049
1050<!-- ======================================================================= -->
1051<div class="doc_subsection">
1052 <a name="ccxx_global_variable">C/C++ global variable information</a>
1053</div>
1054
1055<div class="doc_text">
1056
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1057<p>Given an integer global variable declared as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1058
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1059<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1060<pre>
1061int MyGlobal = 100;
1062</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1063</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1064
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1065<p>a C/C++ front-end would generate the following descriptors:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1066
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1067<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1068<pre>
1069;;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1070;; Define the global itself.
1071;;
1072%MyGlobal = global int 100
1073...
1074;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1075;; List of debug info of globals
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1076;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1077!llvm.dbg.gv = !{!0}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1078
1079;;
1080;; Define the global variable descriptor. Note the reference to the global
1081;; variable anchor and the global variable itself.
1082;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1083!0 = metadata !{
1084 i32 458804, ;; Tag
1085 i32 0, ;; Unused
1086 metadata !1, ;; Context
1087 metadata !"MyGlobal", ;; Name
1088 metadata !"MyGlobal", ;; Display Name
1089 metadata !"MyGlobal", ;; Linkage Name
1090 metadata !1, ;; Compile Unit
1091 i32 1, ;; Line Number
1092 metadata !2, ;; Type
1093 i1 false, ;; Is a local variable
1094 i1 true, ;; Is this a definition
1095 i32* @MyGlobal ;; The global variable
1096}
1097
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1098;;
1099;; Define the basic type of 32 bit signed integer. Note that since int is an
1100;; intrinsic type the source file is NULL and line 0.
1101;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1102!2 = metadata !{
1103 i32 458788, ;; Tag
1104 metadata !1, ;; Context
1105 metadata !"int", ;; Name
1106 metadata !1, ;; Compile Unit
1107 i32 0, ;; Line number
1108 i64 32, ;; Size in Bits
1109 i64 32, ;; Align in Bits
1110 i64 0, ;; Offset in Bits
1111 i32 0, ;; Flags
1112 i32 5 ;; Encoding
1113}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1114
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1115</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1116</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1117
1118</div>
1119
1120<!-- ======================================================================= -->
1121<div class="doc_subsection">
1122 <a name="ccxx_subprogram">C/C++ function information</a>
1123</div>
1124
1125<div class="doc_text">
1126
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1127<p>Given a function declared as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1128
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1129<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1130<pre>
1131int main(int argc, char *argv[]) {
1132 return 0;
1133}
1134</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1135</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1136
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1137<p>a C/C++ front-end would generate the following descriptors:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1138
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1139<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1140<pre>
1141;;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1142;; Define the anchor for subprograms. Note that the second field of the
1143;; anchor is 46, which is the same as the tag for subprograms
1144;; (46 = DW_TAG_subprogram.)
1145;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1146!0 = metadata !{
1147 i32 458798, ;; Tag
1148 i32 0, ;; Unused
1149 metadata !1, ;; Context
1150 metadata !"main", ;; Name
1151 metadata !"main", ;; Display name
1152 metadata !"main", ;; Linkage name
1153 metadata !1, ;; Compile unit
1154 i32 1, ;; Line number
1155 metadata !2, ;; Type
1156 i1 false, ;; Is local
1157 i1 true ;; Is definition
1158}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1159;;
1160;; Define the subprogram itself.
1161;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1162define i32 @main(i32 %argc, i8** %argv) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1163...
1164}
1165</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1166</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1167
1168</div>
1169
1170<!-- ======================================================================= -->
1171<div class="doc_subsection">
1172 <a name="ccxx_basic_types">C/C++ basic types</a>
1173</div>
1174
1175<div class="doc_text">
1176
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1177<p>The following are the basic type descriptors for C/C++ core types:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1178
1179</div>
1180
1181<!-- ======================================================================= -->
1182<div class="doc_subsubsection">
1183 <a name="ccxx_basic_type_bool">bool</a>
1184</div>
1185
1186<div class="doc_text">
1187
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1188<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1189<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1190!2 = metadata !{
1191 i32 458788, ;; Tag
1192 metadata !1, ;; Context
1193 metadata !"bool", ;; Name
1194 metadata !1, ;; Compile Unit
1195 i32 0, ;; Line number
1196 i64 8, ;; Size in Bits
1197 i64 8, ;; Align in Bits
1198 i64 0, ;; Offset in Bits
1199 i32 0, ;; Flags
1200 i32 2 ;; Encoding
1201}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1202</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1203</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1204
1205</div>
1206
1207<!-- ======================================================================= -->
1208<div class="doc_subsubsection">
1209 <a name="ccxx_basic_char">char</a>
1210</div>
1211
1212<div class="doc_text">
1213
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1214<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1215<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1216!2 = metadata !{
1217 i32 458788, ;; Tag
1218 metadata !1, ;; Context
1219 metadata !"char", ;; Name
1220 metadata !1, ;; Compile Unit
1221 i32 0, ;; Line number
1222 i64 8, ;; Size in Bits
1223 i64 8, ;; Align in Bits
1224 i64 0, ;; Offset in Bits
1225 i32 0, ;; Flags
1226 i32 6 ;; Encoding
1227}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1228</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1229</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1230
1231</div>
1232
1233<!-- ======================================================================= -->
1234<div class="doc_subsubsection">
1235 <a name="ccxx_basic_unsigned_char">unsigned char</a>
1236</div>
1237
1238<div class="doc_text">
1239
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1240<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1241<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1242!2 = metadata !{
1243 i32 458788, ;; Tag
1244 metadata !1, ;; Context
1245 metadata !"unsigned char",
1246 metadata !1, ;; Compile Unit
1247 i32 0, ;; Line number
1248 i64 8, ;; Size in Bits
1249 i64 8, ;; Align in Bits
1250 i64 0, ;; Offset in Bits
1251 i32 0, ;; Flags
1252 i32 8 ;; Encoding
1253}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1254</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1255</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1256
1257</div>
1258
1259<!-- ======================================================================= -->
1260<div class="doc_subsubsection">
1261 <a name="ccxx_basic_short">short</a>
1262</div>
1263
1264<div class="doc_text">
1265
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1266<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1267<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1268!2 = metadata !{
1269 i32 458788, ;; Tag
1270 metadata !1, ;; Context
1271 metadata !"short int",
1272 metadata !1, ;; Compile Unit
1273 i32 0, ;; Line number
1274 i64 16, ;; Size in Bits
1275 i64 16, ;; Align in Bits
1276 i64 0, ;; Offset in Bits
1277 i32 0, ;; Flags
1278 i32 5 ;; Encoding
1279}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1280</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1281</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1282
1283</div>
1284
1285<!-- ======================================================================= -->
1286<div class="doc_subsubsection">
1287 <a name="ccxx_basic_unsigned_short">unsigned short</a>
1288</div>
1289
1290<div class="doc_text">
1291
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1292<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1293<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1294!2 = metadata !{
1295 i32 458788, ;; Tag
1296 metadata !1, ;; Context
1297 metadata !"short unsigned int",
1298 metadata !1, ;; Compile Unit
1299 i32 0, ;; Line number
1300 i64 16, ;; Size in Bits
1301 i64 16, ;; Align in Bits
1302 i64 0, ;; Offset in Bits
1303 i32 0, ;; Flags
1304 i32 7 ;; Encoding
1305}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1306</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1307</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1308
1309</div>
1310
1311<!-- ======================================================================= -->
1312<div class="doc_subsubsection">
1313 <a name="ccxx_basic_int">int</a>
1314</div>
1315
1316<div class="doc_text">
1317
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1318<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1319<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1320!2 = metadata !{
1321 i32 458788, ;; Tag
1322 metadata !1, ;; Context
1323 metadata !"int", ;; Name
1324 metadata !1, ;; Compile Unit
1325 i32 0, ;; Line number
1326 i64 32, ;; Size in Bits
1327 i64 32, ;; Align in Bits
1328 i64 0, ;; Offset in Bits
1329 i32 0, ;; Flags
1330 i32 5 ;; Encoding
1331}
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1332</pre></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1333
1334</div>
1335
1336<!-- ======================================================================= -->
1337<div class="doc_subsubsection">
1338 <a name="ccxx_basic_unsigned_int">unsigned int</a>
1339</div>
1340
1341<div class="doc_text">
1342
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1343<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1344<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1345!2 = metadata !{
1346 i32 458788, ;; Tag
1347 metadata !1, ;; Context
1348 metadata !"unsigned int",
1349 metadata !1, ;; Compile Unit
1350 i32 0, ;; Line number
1351 i64 32, ;; Size in Bits
1352 i64 32, ;; Align in Bits
1353 i64 0, ;; Offset in Bits
1354 i32 0, ;; Flags
1355 i32 7 ;; Encoding
1356}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1357</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1358</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1359
1360</div>
1361
1362<!-- ======================================================================= -->
1363<div class="doc_subsubsection">
1364 <a name="ccxx_basic_long_long">long long</a>
1365</div>
1366
1367<div class="doc_text">
1368
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1369<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1370<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1371!2 = metadata !{
1372 i32 458788, ;; Tag
1373 metadata !1, ;; Context
1374 metadata !"long long int",
1375 metadata !1, ;; Compile Unit
1376 i32 0, ;; Line number
1377 i64 64, ;; Size in Bits
1378 i64 64, ;; Align in Bits
1379 i64 0, ;; Offset in Bits
1380 i32 0, ;; Flags
1381 i32 5 ;; Encoding
1382}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1383</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1384</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1385
1386</div>
1387
1388<!-- ======================================================================= -->
1389<div class="doc_subsubsection">
1390 <a name="ccxx_basic_unsigned_long_long">unsigned long long</a>
1391</div>
1392
1393<div class="doc_text">
1394
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1395<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1396<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1397!2 = metadata !{
1398 i32 458788, ;; Tag
1399 metadata !1, ;; Context
1400 metadata !"long long unsigned int",
1401 metadata !1, ;; Compile Unit
1402 i32 0, ;; Line number
1403 i64 64, ;; Size in Bits
1404 i64 64, ;; Align in Bits
1405 i64 0, ;; Offset in Bits
1406 i32 0, ;; Flags
1407 i32 7 ;; Encoding
1408}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1409</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1410</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1411
1412</div>
1413
1414<!-- ======================================================================= -->
1415<div class="doc_subsubsection">
1416 <a name="ccxx_basic_float">float</a>
1417</div>
1418
1419<div class="doc_text">
1420
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1421<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1422<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1423!2 = metadata !{
1424 i32 458788, ;; Tag
1425 metadata !1, ;; Context
1426 metadata !"float",
1427 metadata !1, ;; Compile Unit
1428 i32 0, ;; Line number
1429 i64 32, ;; Size in Bits
1430 i64 32, ;; Align in Bits
1431 i64 0, ;; Offset in Bits
1432 i32 0, ;; Flags
1433 i32 4 ;; Encoding
1434}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1435</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1436</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1437
1438</div>
1439
1440<!-- ======================================================================= -->
1441<div class="doc_subsubsection">
1442 <a name="ccxx_basic_double">double</a>
1443</div>
1444
1445<div class="doc_text">
1446
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1447<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1448<pre>
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1449!2 = metadata !{
1450 i32 458788, ;; Tag
1451 metadata !1, ;; Context
1452 metadata !"double",;; Name
1453 metadata !1, ;; Compile Unit
1454 i32 0, ;; Line number
1455 i64 64, ;; Size in Bits
1456 i64 64, ;; Align in Bits
1457 i64 0, ;; Offset in Bits
1458 i32 0, ;; Flags
1459 i32 4 ;; Encoding
1460}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1461</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1462</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1463
1464</div>
1465
1466<!-- ======================================================================= -->
1467<div class="doc_subsection">
1468 <a name="ccxx_derived_types">C/C++ derived types</a>
1469</div>
1470
1471<div class="doc_text">
1472
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1473<p>Given the following as an example of C/C++ derived type:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1474
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1475<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1476<pre>
1477typedef const int *IntPtr;
1478</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1479</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1480
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1481<p>a C/C++ front-end would generate the following descriptors:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1482
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1483<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1484<pre>
1485;;
1486;; Define the typedef "IntPtr".
1487;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1488!2 = metadata !{
1489 i32 458774, ;; Tag
1490 metadata !1, ;; Context
1491 metadata !"IntPtr", ;; Name
1492 metadata !3, ;; Compile unit
1493 i32 0, ;; Line number
1494 i64 0, ;; Size in bits
1495 i64 0, ;; Align in bits
1496 i64 0, ;; Offset in bits
1497 i32 0, ;; Flags
1498 metadata !4 ;; Derived From type
1499}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1500
1501;;
1502;; Define the pointer type.
1503;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1504!4 = metadata !{
1505 i32 458767, ;; Tag
1506 metadata !1, ;; Context
1507 metadata !"", ;; Name
1508 metadata !1, ;; Compile unit
1509 i32 0, ;; Line number
1510 i64 64, ;; Size in bits
1511 i64 64, ;; Align in bits
1512 i64 0, ;; Offset in bits
1513 i32 0, ;; Flags
1514 metadata !5 ;; Derived From type
1515}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1516;;
1517;; Define the const type.
1518;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1519!5 = metadata !{
1520 i32 458790, ;; Tag
1521 metadata !1, ;; Context
1522 metadata !"", ;; Name
1523 metadata !1, ;; Compile unit
1524 i32 0, ;; Line number
1525 i64 32, ;; Size in bits
1526 i64 32, ;; Align in bits
1527 i64 0, ;; Offset in bits
1528 i32 0, ;; Flags
1529 metadata !6 ;; Derived From type
1530}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1531;;
1532;; Define the int type.
1533;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1534!6 = metadata !{
1535 i32 458788, ;; Tag
1536 metadata !1, ;; Context
1537 metadata !"int", ;; Name
1538 metadata !1, ;; Compile unit
1539 i32 0, ;; Line number
1540 i64 32, ;; Size in bits
1541 i64 32, ;; Align in bits
1542 i64 0, ;; Offset in bits
1543 i32 0, ;; Flags
1544 5 ;; Encoding
1545}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1546</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1547</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1548
1549</div>
1550
1551<!-- ======================================================================= -->
1552<div class="doc_subsection">
1553 <a name="ccxx_composite_types">C/C++ struct/union types</a>
1554</div>
1555
1556<div class="doc_text">
1557
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1558<p>Given the following as an example of C/C++ struct type:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1559
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1560<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1561<pre>
1562struct Color {
1563 unsigned Red;
1564 unsigned Green;
1565 unsigned Blue;
1566};
1567</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1568</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1569
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1570<p>a C/C++ front-end would generate the following descriptors:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1571
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1572<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1573<pre>
1574;;
1575;; Define basic type for unsigned int.
1576;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1577!5 = metadata !{
1578 i32 458788, ;; Tag
1579 metadata !1, ;; Context
1580 metadata !"unsigned int",
1581 metadata !1, ;; Compile Unit
1582 i32 0, ;; Line number
1583 i64 32, ;; Size in Bits
1584 i64 32, ;; Align in Bits
1585 i64 0, ;; Offset in Bits
1586 i32 0, ;; Flags
1587 i32 7 ;; Encoding
1588}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1589;;
1590;; Define composite type for struct Color.
1591;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1592!2 = metadata !{
1593 i32 458771, ;; Tag
1594 metadata !1, ;; Context
1595 metadata !"Color", ;; Name
1596 metadata !1, ;; Compile unit
1597 i32 1, ;; Line number
1598 i64 96, ;; Size in bits
1599 i64 32, ;; Align in bits
1600 i64 0, ;; Offset in bits
1601 i32 0, ;; Flags
1602 null, ;; Derived From
1603 metadata !3, ;; Elements
1604 i32 0 ;; Runtime Language
1605}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1606
1607;;
1608;; Define the Red field.
1609;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1610!4 = metadata !{
1611 i32 458765, ;; Tag
1612 metadata !1, ;; Context
1613 metadata !"Red", ;; Name
1614 metadata !1, ;; Compile Unit
1615 i32 2, ;; Line number
1616 i64 32, ;; Size in bits
1617 i64 32, ;; Align in bits
1618 i64 0, ;; Offset in bits
1619 i32 0, ;; Flags
1620 metadata !5 ;; Derived From type
1621}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1622
1623;;
1624;; Define the Green field.
1625;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1626!6 = metadata !{
1627 i32 458765, ;; Tag
1628 metadata !1, ;; Context
1629 metadata !"Green", ;; Name
1630 metadata !1, ;; Compile Unit
1631 i32 3, ;; Line number
1632 i64 32, ;; Size in bits
1633 i64 32, ;; Align in bits
1634 i64 32, ;; Offset in bits
1635 i32 0, ;; Flags
1636 metadata !5 ;; Derived From type
1637}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1638
1639;;
1640;; Define the Blue field.
1641;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1642!7 = metadata !{
1643 i32 458765, ;; Tag
1644 metadata !1, ;; Context
1645 metadata !"Blue", ;; Name
1646 metadata !1, ;; Compile Unit
1647 i32 4, ;; Line number
1648 i64 32, ;; Size in bits
1649 i64 32, ;; Align in bits
1650 i64 64, ;; Offset in bits
1651 i32 0, ;; Flags
1652 metadata !5 ;; Derived From type
1653}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1654
1655;;
1656;; Define the array of fields used by the composite type Color.
1657;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1658!3 = metadata !{metadata !4, metadata !6, metadata !7}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1659</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1660</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1661
1662</div>
1663
1664<!-- ======================================================================= -->
1665<div class="doc_subsection">
1666 <a name="ccxx_enumeration_types">C/C++ enumeration types</a>
1667</div>
1668
1669<div class="doc_text">
1670
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1671<p>Given the following as an example of C/C++ enumeration type:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1672
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1673<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1674<pre>
1675enum Trees {
1676 Spruce = 100,
1677 Oak = 200,
1678 Maple = 300
1679};
1680</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1681</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1682
Misha Brukmane5b22d42008-12-16 02:54:22 +0000[diff] [blame]1683<p>a C/C++ front-end would generate the following descriptors:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1684
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1685<div class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1686<pre>
1687;;
1688;; Define composite type for enum Trees
1689;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1690!2 = metadata !{
1691 i32 458756, ;; Tag
1692 metadata !1, ;; Context
1693 metadata !"Trees", ;; Name
1694 metadata !1, ;; Compile unit
1695 i32 1, ;; Line number
1696 i64 32, ;; Size in bits
1697 i64 32, ;; Align in bits
1698 i64 0, ;; Offset in bits
1699 i32 0, ;; Flags
1700 null, ;; Derived From type
1701 metadata !3, ;; Elements
1702 i32 0 ;; Runtime language
1703}
Devang Patel57b83c72009-08-25 05:24:07 +0000[diff] [blame]1704
Devang Patel94060422009-08-26 05:01:18 +0000[diff] [blame]1705;;
1706;; Define the array of enumerators used by composite type Trees.
1707;;
Devang Patel15e723d2009-08-28 23:24:31 +0000[diff] [blame]1708!3 = metadata !{metadata !4, metadata !5, metadata !6}
1709
1710;;
1711;; Define Spruce enumerator.
1712;;
1713!4 = metadata !{i32 458792, metadata !"Spruce", i64 100}
1714
1715;;
1716;; Define Oak enumerator.
1717;;
1718!5 = metadata !{i32 458792, metadata !"Oak", i64 200}
1719
1720;;
1721;; Define Maple enumerator.
1722;;
1723!6 = metadata !{i32 458792, metadata !"Maple", i64 300}
1724
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1725</pre>
Bill Wendlingde024832009-05-17 05:52:39 +0000[diff] [blame]1726</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1727
1728</div>
1729
1730<!-- *********************************************************************** -->
1731
1732<hr>
1733<address>
1734 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1738
1739 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1740 <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br>
1741 Last modified: $Date$
1742</address>
1743
1744</body>
1745</html>