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Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]6 <title>Source Level Debugging with LLVM</title>
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10
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]11<h1>Source Level Debugging with LLVM</h1>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]12
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]13<table class="layout" style="width:100%">
14 <tr class="layout">
15 <td class="left">
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]16<ul>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]17 <li><a href="#introduction">Introduction</a>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]18 <ol>
19 <li><a href="#phil">Philosophy behind LLVM debugging information</a></li>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]20 <li><a href="#consumers">Debug information consumers</a></li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]21 <li><a href="#debugopt">Debugging optimized code</a></li>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]22 </ol></li>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]23 <li><a href="#format">Debugging information format</a>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]24 <ol>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]25 <li><a href="#debug_info_descriptors">Debug information descriptors</a>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]26 <ul>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]27 <li><a href="#format_compile_units">Compile unit descriptors</a></li>
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]28 <li><a href="#format_files">File descriptors</a></li>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]29 <li><a href="#format_global_variables">Global variable descriptors</a></li>
30 <li><a href="#format_subprograms">Subprogram descriptors</a></li>
Jim Laskey9dcffe72006-03-15 19:10:52 +0000[diff] [blame]31 <li><a href="#format_blocks">Block descriptors</a></li>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]32 <li><a href="#format_basic_type">Basic type descriptors</a></li>
33 <li><a href="#format_derived_type">Derived type descriptors</a></li>
34 <li><a href="#format_composite_type">Composite type descriptors</a></li>
35 <li><a href="#format_subrange">Subrange descriptors</a></li>
36 <li><a href="#format_enumeration">Enumerator descriptors</a></li>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]37 <li><a href="#format_variables">Local variables</a></li>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]38 </ul></li>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]39 <li><a href="#format_common_intrinsics">Debugger intrinsic functions</a>
40 <ul>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]41 <li><a href="#format_common_declare">llvm.dbg.declare</a></li>
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000[diff] [blame]42 <li><a href="#format_common_value">llvm.dbg.value</a></li>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]43 </ul></li>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]44 </ol></li>
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]45 <li><a href="#format_common_lifetime">Object lifetimes and scoping</a></li>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]46 <li><a href="#ccxx_frontend">C/C++ front-end specific debug information</a>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]47 <ol>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]48 <li><a href="#ccxx_compile_units">C/C++ source file information</a></li>
49 <li><a href="#ccxx_global_variable">C/C++ global variable information</a></li>
50 <li><a href="#ccxx_subprogram">C/C++ function information</a></li>
51 <li><a href="#ccxx_basic_types">C/C++ basic types</a></li>
52 <li><a href="#ccxx_derived_types">C/C++ derived types</a></li>
53 <li><a href="#ccxx_composite_types">C/C++ struct/union types</a></li>
54 <li><a href="#ccxx_enumeration_types">C/C++ enumeration types</a></li>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]55 </ol></li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]56</ul>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]57</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]58<td class="right">
Misha Brukman3c1f8e72004-05-12 21:26:16 +0000[diff] [blame]59<img src="img/venusflytrap.jpg" alt="A leafy and green bug eater" width="247"
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]60height="369">
61</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]62</tr></table>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]63
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]64<div class="doc_author">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]65 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
Jim Laskey6e8a2f42007-03-14 19:32:21 +0000[diff] [blame]66 and <a href="mailto:jlaskey@mac.com">Jim Laskey</a></p>
Chris Lattner020e1fc2004-05-23 21:07:27 +0000[diff] [blame]67</div>
68
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]69
70<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]71<h2><a name="introduction">Introduction</a></h2>
Misha Brukmancda6a9b2004-12-09 20:27:37 +0000[diff] [blame]72<!-- *********************************************************************** -->
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]73
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]74<div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]75
76<p>This document is the central repository for all information pertaining to
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]77 debug information in LLVM. It describes the <a href="#format">actual format
78 that the LLVM debug information</a> takes, which is useful for those
79 interested in creating front-ends or dealing directly with the information.
Chris Lattnercb3f64f2009-07-18 21:47:15 +0000[diff] [blame]80 Further, this document provides specific examples of what debug information
Chris Lattner92ec3d12011-01-18 06:12:10 +0000[diff] [blame]81 for C/C++ looks like.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]82
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]83<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]84<h3>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]85 <a name="phil">Philosophy behind LLVM debugging information</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]86</h3>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]87
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]88<div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]89
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]90<p>The idea of the LLVM debugging information is to capture how the important
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]91 pieces of the source-language's Abstract Syntax Tree map onto LLVM code.
92 Several design aspects have shaped the solution that appears here. The
93 important ones are:</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]94
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]95<ul>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]96 <li>Debugging information should have very little impact on the rest of the
97 compiler. No transformations, analyses, or code generators should need to
98 be modified because of debugging information.</li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]99
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]100 <li>LLVM optimizations should interact in <a href="#debugopt">well-defined and
101 easily described ways</a> with the debugging information.</li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]102
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]103 <li>Because LLVM is designed to support arbitrary programming languages,
104 LLVM-to-LLVM tools should not need to know anything about the semantics of
105 the source-level-language.</li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]106
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]107 <li>Source-level languages are often <b>widely</b> different from one another.
108 LLVM should not put any restrictions of the flavor of the source-language,
109 and the debugging information should work with any language.</li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]110
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]111 <li>With code generator support, it should be possible to use an LLVM compiler
112 to compile a program to native machine code and standard debugging
113 formats. This allows compatibility with traditional machine-code level
114 debuggers, like GDB or DBX.</li>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]115</ul>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]116
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]117<p>The approach used by the LLVM implementation is to use a small set
118 of <a href="#format_common_intrinsics">intrinsic functions</a> to define a
119 mapping between LLVM program objects and the source-level objects. The
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]120 description of the source-level program is maintained in LLVM metadata
121 in an <a href="#ccxx_frontend">implementation-defined format</a>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]122 (the C/C++ front-end currently uses working draft 7 of
123 the <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3
124 standard</a>).</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]125
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]126<p>When a program is being debugged, a debugger interacts with the user and
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]127 turns the stored debug information into source-language specific information.
128 As such, a debugger must be aware of the source-language, and is thus tied to
129 a specific language or family of languages.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]130
131</div>
132
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]133<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]134<h3>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]135 <a name="consumers">Debug information consumers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]136</h3>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]137
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]138<div>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]139
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]140<p>The role of debug information is to provide meta information normally
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]141 stripped away during the compilation process. This meta information provides
142 an LLVM user a relationship between generated code and the original program
143 source code.</p>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]144
Chris Lattner904f2172010-04-05 04:11:11 +0000[diff] [blame]145<p>Currently, debug information is consumed by DwarfDebug to produce dwarf
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]146 information used by the gdb debugger. Other targets could use the same
147 information to produce stabs or other debug forms.</p>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]148
149<p>It would also be reasonable to use debug information to feed profiling tools
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]150 for analysis of generated code, or, tools for reconstructing the original
151 source from generated code.</p>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]152
153<p>TODO - expound a bit more.</p>
154
155</div>
156
157<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]158<h3>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]159 <a name="debugopt">Debugging optimized code</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]160</h3>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]161
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]162<div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]163
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]164<p>An extremely high priority of LLVM debugging information is to make it
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]165 interact well with optimizations and analysis. In particular, the LLVM debug
166 information provides the following guarantees:</p>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]167
168<ul>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]169 <li>LLVM debug information <b>always provides information to accurately read
170 the source-level state of the program</b>, regardless of which LLVM
171 optimizations have been run, and without any modification to the
172 optimizations themselves. However, some optimizations may impact the
173 ability to modify the current state of the program with a debugger, such
174 as setting program variables, or calling functions that have been
175 deleted.</li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]176
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]177 <li>LLVM optimizations gracefully interact with debugging information. If
178 they are not aware of debug information, they are automatically disabled
179 as necessary in the cases that would invalidate the debug info. This
180 retains the LLVM features, making it easy to write new
181 transformations.</li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]182
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]183 <li>As desired, LLVM optimizations can be upgraded to be aware of the LLVM
184 debugging information, allowing them to update the debugging information
185 as they perform aggressive optimizations. This means that, with effort,
186 the LLVM optimizers could optimize debug code just as well as non-debug
187 code.</li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]188
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]189 <li>LLVM debug information does not prevent many important optimizations from
190 happening (for example inlining, basic block reordering/merging/cleanup,
191 tail duplication, etc), further reducing the amount of the compiler that
192 eventually is "aware" of debugging information.</li>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]193
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]194 <li>LLVM debug information is automatically optimized along with the rest of
195 the program, using existing facilities. For example, duplicate
196 information is automatically merged by the linker, and unused information
197 is automatically removed.</li>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]198</ul>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]199
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]200<p>Basically, the debug information allows you to compile a program with
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]201 "<tt>-O0 -g</tt>" and get full debug information, allowing you to arbitrarily
202 modify the program as it executes from a debugger. Compiling a program with
203 "<tt>-O3 -g</tt>" gives you full debug information that is always available
204 and accurate for reading (e.g., you get accurate stack traces despite tail
205 call elimination and inlining), but you might lose the ability to modify the
206 program and call functions where were optimized out of the program, or
207 inlined away completely.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]208
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]209<p><a href="TestingGuide.html#quicktestsuite">LLVM test suite</a> provides a
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]210 framework to test optimizer's handling of debugging information. It can be
211 run like this:</p>
Devang Patelb885a912008-11-21 19:35:57 +0000[diff] [blame]212
213<div class="doc_code">
214<pre>
215% cd llvm/projects/test-suite/MultiSource/Benchmarks # or some other level
216% make TEST=dbgopt
217</pre>
218</div>
219
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]220<p>This will test impact of debugging information on optimization passes. If
221 debugging information influences optimization passes then it will be reported
222 as a failure. See <a href="TestingGuide.html">TestingGuide</a> for more
223 information on LLVM test infrastructure and how to run various tests.</p>
Devang Patelb885a912008-11-21 19:35:57 +0000[diff] [blame]224
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]225</div>
226
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]227</div>
228
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]229<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]230<h2>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]231 <a name="format">Debugging information format</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]232</h2>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]233<!-- *********************************************************************** -->
234
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]235<div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]236
237<p>LLVM debugging information has been carefully designed to make it possible
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]238 for the optimizer to optimize the program and debugging information without
239 necessarily having to know anything about debugging information. In
John Criswell2a4b0802010-03-17 15:01:50 +0000[diff] [blame]240 particular, the use of metadata avoids duplicated debugging information from
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]241 the beginning, and the global dead code elimination pass automatically
242 deletes debugging information for a function if it decides to delete the
243 function. </p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]244
245<p>To do this, most of the debugging information (descriptors for types,
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]246 variables, functions, source files, etc) is inserted by the language
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]247 front-end in the form of LLVM metadata. </p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]248
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]249<p>Debug information is designed to be agnostic about the target debugger and
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]250 debugging information representation (e.g. DWARF/Stabs/etc). It uses a
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]251 generic pass to decode the information that represents variables, types,
252 functions, namespaces, etc: this allows for arbitrary source-language
253 semantics and type-systems to be used, as long as there is a module
254 written for the target debugger to interpret the information. </p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]255
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]256<p>To provide basic functionality, the LLVM debugger does have to make some
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]257 assumptions about the source-level language being debugged, though it keeps
258 these to a minimum. The only common features that the LLVM debugger assumes
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]259 exist are <a href="#format_files">source files</a>,
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]260 and <a href="#format_global_variables">program objects</a>. These abstract
261 objects are used by a debugger to form stack traces, show information about
262 local variables, etc.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]263
264<p>This section of the documentation first describes the representation aspects
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]265 common to any source-language. The <a href="#ccxx_frontend">next section</a>
266 describes the data layout conventions used by the C and C++ front-ends.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]267
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]268<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]269<h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]270 <a name="debug_info_descriptors">Debug information descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]271</h3>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]272
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]273<div>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]274
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]275<p>In consideration of the complexity and volume of debug information, LLVM
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]276 provides a specification for well formed debug descriptors. </p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]277
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]278<p>Consumers of LLVM debug information expect the descriptors for program
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]279 objects to start in a canonical format, but the descriptors can include
280 additional information appended at the end that is source-language
281 specific. All LLVM debugging information is versioned, allowing backwards
282 compatibility in the case that the core structures need to change in some
283 way. Also, all debugging information objects start with a tag to indicate
284 what type of object it is. The source-language is allowed to define its own
285 objects, by using unreserved tag numbers. We recommend using with tags in
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]286 the range 0x1000 through 0x2000 (there is a defined enum DW_TAG_user_base =
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]287 0x1000.)</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]288
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]289<p>The fields of debug descriptors used internally by LLVM
Nick Lewyckya87014f2010-03-31 07:50:17 +0000[diff] [blame]290 are restricted to only the simple data types <tt>i32</tt>, <tt>i1</tt>,
291 <tt>float</tt>, <tt>double</tt>, <tt>mdstring</tt> and <tt>mdnode</tt>. </p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]292
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]293<div class="doc_code">
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]294<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]295!1 = metadata !{
Nick Lewyckya87014f2010-03-31 07:50:17 +0000[diff] [blame]296 i32, ;; A tag
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]297 ...
298}
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]299</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]300</div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]301
Jim Laskeyb2ff2d42006-06-16 13:14:03 +0000[diff] [blame]302<p><a name="LLVMDebugVersion">The first field of a descriptor is always an
Nick Lewyckya87014f2010-03-31 07:50:17 +0000[diff] [blame]303 <tt>i32</tt> containing a tag value identifying the content of the
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]304 descriptor. The remaining fields are specific to the descriptor. The values
305 of tags are loosely bound to the tag values of DWARF information entries.
306 However, that does not restrict the use of the information supplied to DWARF
307 targets. To facilitate versioning of debug information, the tag is augmented
Nick Lewyckya87014f2010-03-31 07:50:17 +0000[diff] [blame]308 with the current debug version (LLVMDebugVersion = 8 &lt;&lt; 16 or 0x80000 or
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]309 524288.)</a></p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]310
Jim Laskeyb2ff2d42006-06-16 13:14:03 +0000[diff] [blame]311<p>The details of the various descriptors follow.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]312
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]313<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]314<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]315 <a name="format_compile_units">Compile unit descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]316</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]317
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]318<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]319
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]320<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]321<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]322!0 = metadata !{
323 i32, ;; Tag = 17 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
324 ;; (DW_TAG_compile_unit)
325 i32, ;; Unused field.
326 i32, ;; DWARF language identifier (ex. DW_LANG_C89)
327 metadata, ;; Source file name
328 metadata, ;; Source file directory (includes trailing slash)
329 metadata ;; Producer (ex. "4.0.1 LLVM (LLVM research group)")
330 i1, ;; True if this is a main compile unit.
331 i1, ;; True if this is optimized.
332 metadata, ;; Flags
333 i32 ;; Runtime version
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]334}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]335</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]336</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]337
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]338<p>These descriptors contain a source language ID for the file (we use the DWARF
339 3.0 ID numbers, such as <tt>DW_LANG_C89</tt>, <tt>DW_LANG_C_plus_plus</tt>,
340 <tt>DW_LANG_Cobol74</tt>, etc), three strings describing the filename,
341 working directory of the compiler, and an identifier string for the compiler
342 that produced it.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]343
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]344<p>Compile unit descriptors provide the root context for objects declared in a
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]345 specific compilation unit. File descriptors are defined using this context.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]346
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]347</div>
348
349<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]350<h4>
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]351 <a name="format_files">File descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]352</h4>
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]353
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]354<div>
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]355
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)
363 metadata ;; Reference to compile unit where defined
364}
365</pre>
366</div>
367
John Criswell2a4b0802010-03-17 15:01:50 +0000[diff] [blame]368<p>These descriptors contain information for a file. Global variables and top
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]369 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
373 information output. Each file descriptor would be defined using a
374 compile unit. </p>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]375
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]376</div>
377
378<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]379<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]380 <a name="format_global_variables">Global variable descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]381</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]382
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]383<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]384
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]385<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]386<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]387!1 = metadata !{
388 i32, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
389 ;; (DW_TAG_variable)
390 i32, ;; Unused field.
391 metadata, ;; Reference to context descriptor
392 metadata, ;; Name
393 metadata, ;; Display name (fully qualified C++ name)
394 metadata, ;; MIPS linkage name (for C++)
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]395 metadata, ;; Reference to file where defined
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]396 i32, ;; Line number where defined
397 metadata, ;; Reference to type descriptor
398 i1, ;; True if the global is local to compile unit (static)
399 i1, ;; True if the global is defined in the compile unit (not extern)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]400 {}* ;; Reference to the global variable
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]401}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]402</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]403</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]404
405<p>These descriptors provide debug information about globals variables. The
Devang Patel1c6b6812011-03-29 17:27:08 +0000[diff] [blame]406provide details such as name, type and where the variable is defined. All
407global variables are collected by named metadata <tt>!llvm.dbg.gv</tt>.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]408
409</div>
410
411<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]412<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]413 <a name="format_subprograms">Subprogram descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]414</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]415
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]416<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]417
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]418<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]419<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]420!2 = metadata !{
421 i32, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
422 ;; (DW_TAG_subprogram)
423 i32, ;; Unused field.
424 metadata, ;; Reference to context descriptor
425 metadata, ;; Name
426 metadata, ;; Display name (fully qualified C++ name)
427 metadata, ;; MIPS linkage name (for C++)
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]428 metadata, ;; Reference to file where defined
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]429 i32, ;; Line number where defined
430 metadata, ;; Reference to type descriptor
431 i1, ;; True if the global is local to compile unit (static)
Devang Patel1d6bbd42011-04-22 23:10:17 +0000[diff] [blame]432 i1, ;; True if the global is defined in the compile unit (not extern)
433 i32, ;; Virtuality, e.g. dwarf::DW_VIRTUALITY__virtual
434 i32, ;; Index into a virtual function
Devang Patele89b7592010-06-04 22:49:55 +0000[diff] [blame]435 metadata, ;; indicates which base type contains the vtable pointer for the
436 ;; derived class
Devang Patel1d6bbd42011-04-22 23:10:17 +0000[diff] [blame]437 i1, ;; isArtificial
438 i1, ;; isOptimized
439 Function *,;; Pointer to LLVM function
440 metadata, ;; Lists function template parameters
441 metadata ;; Function declaration descriptor
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]442}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]443</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]444</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]445
446<p>These descriptors provide debug information about functions, methods and
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]447 subprograms. They provide details such as name, return types and the source
Devang Patel1c6b6812011-03-29 17:27:08 +0000[diff] [blame]448 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 +0000[diff] [blame]452
453</div>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]454
Jim Laskey9dcffe72006-03-15 19:10:52 +0000[diff] [blame]455<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]456<h4>
Jim Laskey9dcffe72006-03-15 19:10:52 +0000[diff] [blame]457 <a name="format_blocks">Block descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]458</h4>
Jim Laskey9dcffe72006-03-15 19:10:52 +0000[diff] [blame]459
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]460<div>
Jim Laskey9dcffe72006-03-15 19:10:52 +0000[diff] [blame]461
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]462<div class="doc_code">
Jim Laskey9dcffe72006-03-15 19:10:52 +0000[diff] [blame]463<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]464!3 = metadata !{
Devang Patel9fbc6802010-10-04 16:51:59 +0000[diff] [blame]465 i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
Devang Patelcac38902010-10-01 22:45:00 +0000[diff] [blame]466 metadata,;; Reference to context descriptor
467 i32, ;; Line number
Devang Patelfb30b852011-03-08 16:25:29 +0000[diff] [blame]468 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 +0000[diff] [blame]471}
Jim Laskey9dcffe72006-03-15 19:10:52 +0000[diff] [blame]472</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]473</div>
Jim Laskey9dcffe72006-03-15 19:10:52 +0000[diff] [blame]474
475<p>These descriptors provide debug information about nested blocks within a
Devang Patelcac38902010-10-01 22:45:00 +0000[diff] [blame]476 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 +0000[diff] [blame]478
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]479</div>
480
481<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]482<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]483 <a name="format_basic_type">Basic type descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]484</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]485
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]486<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]487
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]488<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]489<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]490!4 = metadata !{
491 i32, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
492 ;; (DW_TAG_base_type)
493 metadata, ;; Reference to context (typically a compile unit)
494 metadata, ;; Name (may be "" for anonymous types)
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]495 metadata, ;; Reference to file where defined (may be NULL)
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]496 i32, ;; Line number where defined (may be 0)
497 i64, ;; Size in bits
498 i64, ;; Alignment in bits
499 i64, ;; Offset in bits
500 i32, ;; Flags
501 i32 ;; DWARF type encoding
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]502}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]503</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]504</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]505
506<p>These descriptors define primitive types used in the code. Example int, bool
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]507 and float. The context provides the scope of the type, which is usually the
508 top level. Since basic types are not usually user defined the compile unit
509 and line number can be left as NULL and 0. The size, alignment and offset
510 are expressed in bits and can be 64 bit values. The alignment is used to
511 round the offset when embedded in a
512 <a href="#format_composite_type">composite type</a> (example to keep float
513 doubles on 64 bit boundaries.) The offset is the bit offset if embedded in
514 a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]515
516<p>The type encoding provides the details of the type. The values are typically
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]517 one of the following:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]518
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]519<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]520<pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]521DW_ATE_address = 1
522DW_ATE_boolean = 2
523DW_ATE_float = 4
524DW_ATE_signed = 5
525DW_ATE_signed_char = 6
526DW_ATE_unsigned = 7
527DW_ATE_unsigned_char = 8
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]528</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]529</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]530
531</div>
532
533<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]534<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]535 <a name="format_derived_type">Derived type descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]536</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]537
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]538<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]539
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]540<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]541<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]542!5 = metadata !{
543 i32, ;; Tag (see below)
544 metadata, ;; Reference to context
545 metadata, ;; Name (may be "" for anonymous types)
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]546 metadata, ;; Reference to file where defined (may be NULL)
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]547 i32, ;; Line number where defined (may be 0)
Devang Patelbed5e7d2010-10-01 19:19:30 +0000[diff] [blame]548 i64, ;; Size in bits
549 i64, ;; Alignment in bits
550 i64, ;; Offset in bits
Devang Patel514b4002011-04-16 00:11:51 +0000[diff] [blame]551 metadata, ;; Reference to type derived from
552 metadata, ;; (optional) Name of the Objective C property assoicated with
553 ;; Objective-C an ivar
554 metadata, ;; (optional) Name of the Objective C property getter selector.
555 metadata, ;; (optional) Name of the Objective C property setter selector.
556 i32 ;; (optional) Objective C property attributes.
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]557}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]558</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]559</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]560
561<p>These descriptors are used to define types derived from other types. The
562value of the tag varies depending on the meaning. The following are possible
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]563tag values:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]564
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]565<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]566<pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]567DW_TAG_formal_parameter = 5
568DW_TAG_member = 13
569DW_TAG_pointer_type = 15
570DW_TAG_reference_type = 16
571DW_TAG_typedef = 22
572DW_TAG_const_type = 38
573DW_TAG_volatile_type = 53
574DW_TAG_restrict_type = 55
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]575</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]576</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]577
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]578<p><tt>DW_TAG_member</tt> is used to define a member of
579 a <a href="#format_composite_type">composite type</a>
580 or <a href="#format_subprograms">subprogram</a>. The type of the member is
581 the <a href="#format_derived_type">derived
582 type</a>. <tt>DW_TAG_formal_parameter</tt> is used to define a member which
583 is a formal argument of a subprogram.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]584
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]585<p><tt>DW_TAG_typedef</tt> is used to provide a name for the derived type.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]586
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]587<p><tt>DW_TAG_pointer_type</tt>,<tt>DW_TAG_reference_type</tt>,
588 <tt>DW_TAG_const_type</tt>, <tt>DW_TAG_volatile_type</tt>
589 and <tt>DW_TAG_restrict_type</tt> are used to qualify
590 the <a href="#format_derived_type">derived type</a>. </p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]591
592<p><a href="#format_derived_type">Derived type</a> location can be determined
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]593 from the compile unit and line number. The size, alignment and offset are
594 expressed in bits and can be 64 bit values. The alignment is used to round
595 the offset when embedded in a <a href="#format_composite_type">composite
596 type</a> (example to keep float doubles on 64 bit boundaries.) The offset is
597 the bit offset if embedded in a <a href="#format_composite_type">composite
598 type</a>.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]599
Devang Patel7846c1e2011-02-03 00:22:17 +0000[diff] [blame]600<p>Note that the <tt>void *</tt> type is expressed as a type derived from NULL.
601</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]602
603</div>
604
605<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]606<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]607 <a name="format_composite_type">Composite type descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]608</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]609
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]610<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]611
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]612<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]613<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]614!6 = metadata !{
615 i32, ;; Tag (see below)
616 metadata, ;; Reference to context
617 metadata, ;; Name (may be "" for anonymous types)
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]618 metadata, ;; Reference to file where defined (may be NULL)
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]619 i32, ;; Line number where defined (may be 0)
620 i64, ;; Size in bits
621 i64, ;; Alignment in bits
622 i64, ;; Offset in bits
623 i32, ;; Flags
624 metadata, ;; Reference to type derived from
625 metadata, ;; Reference to array of member descriptors
626 i32 ;; Runtime languages
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]627}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]628</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]629</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]630
631<p>These descriptors are used to define types that are composed of 0 or more
632elements. The value of the tag varies depending on the meaning. The following
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]633are possible tag values:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]634
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]635<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]636<pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]637DW_TAG_array_type = 1
638DW_TAG_enumeration_type = 4
639DW_TAG_structure_type = 19
640DW_TAG_union_type = 23
641DW_TAG_vector_type = 259
Bruno Cardoso Lopes9d809ca2009-05-29 17:08:57 +0000[diff] [blame]642DW_TAG_subroutine_type = 21
643DW_TAG_inheritance = 28
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]644</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]645</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]646
Jim Laskey19f964e2006-06-15 20:51:43 +0000[diff] [blame]647<p>The vector flag indicates that an array type is a native packed vector.</p>
648
Jim Laskeyb2ff2d42006-06-16 13:14:03 +0000[diff] [blame]649<p>The members of array types (tag = <tt>DW_TAG_array_type</tt>) or vector types
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]650 (tag = <tt>DW_TAG_vector_type</tt>) are <a href="#format_subrange">subrange
651 descriptors</a>, each representing the range of subscripts at that level of
652 indexing.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]653
654<p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]655 <a href="#format_enumeration">enumerator descriptors</a>, each representing
Devang Patel1c6b6812011-03-29 17:27:08 +0000[diff] [blame]656 the definition of enumeration value for the set. All enumeration type
657 descriptors are collected by named metadata <tt>!llvm.dbg.enum</tt>.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]658
659<p>The members of structure (tag = <tt>DW_TAG_structure_type</tt>) or union (tag
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]660 = <tt>DW_TAG_union_type</tt>) types are any one of
661 the <a href="#format_basic_type">basic</a>,
662 <a href="#format_derived_type">derived</a>
663 or <a href="#format_composite_type">composite</a> type descriptors, each
664 representing a field member of the structure or union.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]665
Jim Laskey4771cca2006-08-21 21:21:06 +0000[diff] [blame]666<p>For C++ classes (tag = <tt>DW_TAG_structure_type</tt>), member descriptors
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]667 provide information about base classes, static members and member
668 functions. If a member is a <a href="#format_derived_type">derived type
669 descriptor</a> and has a tag of <tt>DW_TAG_inheritance</tt>, then the type
670 represents a base class. If the member of is
671 a <a href="#format_global_variables">global variable descriptor</a> then it
672 represents a static member. And, if the member is
673 a <a href="#format_subprograms">subprogram descriptor</a> then it represents
674 a member function. For static members and member
675 functions, <tt>getName()</tt> returns the members link or the C++ mangled
676 name. <tt>getDisplayName()</tt> the simplied version of the name.</p>
Jim Laskey4771cca2006-08-21 21:21:06 +0000[diff] [blame]677
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]678<p>The first member of subroutine (tag = <tt>DW_TAG_subroutine_type</tt>) type
679 elements is the return type for the subroutine. The remaining elements are
680 the formal arguments to the subroutine.</p>
Jim Laskey4810c262006-06-20 21:13:20 +0000[diff] [blame]681
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]682<p><a href="#format_composite_type">Composite type</a> location can be
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]683 determined from the compile unit and line number. The size, alignment and
684 offset are expressed in bits and can be 64 bit values. The alignment is used
685 to round the offset when embedded in
686 a <a href="#format_composite_type">composite type</a> (as an example, to keep
687 float doubles on 64 bit boundaries.) The offset is the bit offset if embedded
688 in a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]689
690</div>
691
692<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]693<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]694 <a name="format_subrange">Subrange descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]695</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]696
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]697<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]698
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]699<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]700<pre>
Devang Patel7846c1e2011-02-03 00:22:17 +0000[diff] [blame]701!42 = metadata !{
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]702 i32, ;; Tag = 33 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subrange_type)
703 i64, ;; Low value
704 i64 ;; High value
705}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]706</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]707</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]708
709<p>These descriptors are used to define ranges of array subscripts for an array
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]710 <a href="#format_composite_type">composite type</a>. The low value defines
711 the lower bounds typically zero for C/C++. The high value is the upper
712 bounds. Values are 64 bit. High - low + 1 is the size of the array. If low
Devang Patel778947c2011-04-08 23:39:38 +0000[diff] [blame]713 > high the array bounds are not included in generated debugging information.
714</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]715
716</div>
717
718<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]719<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]720 <a name="format_enumeration">Enumerator descriptors</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]721</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]722
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]723<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]724
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]725<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]726<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]727!6 = metadata !{
728 i32, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
729 ;; (DW_TAG_enumerator)
730 metadata, ;; Name
731 i64 ;; Value
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]732}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]733</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]734</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]735
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]736<p>These descriptors are used to define members of an
737 enumeration <a href="#format_composite_type">composite type</a>, it
738 associates the name to the value.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]739
740</div>
741
742<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]743<h4>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]744 <a name="format_variables">Local variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]745</h4>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]746
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]747<div>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]748
749<div class="doc_code">
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]750<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]751!7 = metadata !{
752 i32, ;; Tag (see below)
753 metadata, ;; Context
754 metadata, ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]755 metadata, ;; Reference to file where defined
Devang Patele1aa67c2011-03-08 16:29:40 +0000[diff] [blame]756 i32, ;; 24 bit - Line number where defined
757 ;; 8 bit - Argument number. 1 indicates 1st argument.
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]758 metadata ;; Type descriptor
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]759}
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]760</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]761</div>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]762
763<p>These descriptors are used to define variables local to a sub program. The
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]764 value of the tag depends on the usage of the variable:</p>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]765
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]766<div class="doc_code">
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]767<pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]768DW_TAG_auto_variable = 256
769DW_TAG_arg_variable = 257
770DW_TAG_return_variable = 258
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]771</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]772</div>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]773
774<p>An auto variable is any variable declared in the body of the function. An
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]775 argument variable is any variable that appears as a formal argument to the
776 function. A return variable is used to track the result of a function and
777 has no source correspondent.</p>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]778
Jim Laskey3481e122006-03-24 09:20:27 +0000[diff] [blame]779<p>The context is either the subprogram or block where the variable is defined.
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]780 Name the source variable name. Compile unit and line indicate where the
781 variable was defined. Type descriptor defines the declared type of the
782 variable.</p>
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]783
784</div>
785
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]786</div>
787
Jim Laskey5dcfd562006-03-23 17:54:33 +0000[diff] [blame]788<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]789<h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]790 <a name="format_common_intrinsics">Debugger intrinsic functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]791</h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]792
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]793<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]794
795<p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]796 provide debug information at various points in generated code.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]797
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]798<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]799<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]800 <a name="format_common_declare">llvm.dbg.declare</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]801</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]802
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]803<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]804<pre>
Devang Patel6df452c2010-10-01 19:22:16 +0000[diff] [blame]805 void %<a href="#format_common_declare">llvm.dbg.declare</a>(metadata, metadata)
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]806</pre>
807
Jim Laskey3481e122006-03-24 09:20:27 +0000[diff] [blame]808<p>This intrinsic provides information about a local element (ex. variable.) The
NAKAMURA Takumi6bd36d52011-04-09 09:51:57 +0000[diff] [blame]809 first argument is metadata holding alloca for the variable. The
Devang Patel9a8539c2011-02-01 17:22:12 +0000[diff] [blame]810 second argument is metadata containing description of the variable. </p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]811</div>
812
813<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]814<h4>
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000[diff] [blame]815 <a name="format_common_value">llvm.dbg.value</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]816</h4>
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000[diff] [blame]817
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]818<div>
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000[diff] [blame]819<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]820 void %<a href="#format_common_value">llvm.dbg.value</a>(metadata, i64, metadata)
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000[diff] [blame]821</pre>
822
823<p>This intrinsic provides information when a user source variable is set to a
824 new value. The first argument is the new value (wrapped as metadata). The
825 second argument is the offset in the user source variable where the new value
Devang Patel9a8539c2011-02-01 17:22:12 +0000[diff] [blame]826 is written. The third argument is metadata containing description of the
827 user source variable. </p>
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000[diff] [blame]828</div>
829
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]830</div>
831
Victor Hernandez0b62cc62010-01-11 22:53:48 +0000[diff] [blame]832<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]833<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]834 <a name="format_common_lifetime">Object lifetimes and scoping</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]835</h3>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]836
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]837<div>
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]838<p>In many languages, the local variables in functions can have their lifetimes
839 or scopes limited to a subset of a function. In the C family of languages,
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]840 for example, variables are only live (readable and writable) within the
841 source block that they are defined in. In functional languages, values are
842 only readable after they have been defined. Though this is a very obvious
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]843 concept, it is non-trivial to model in LLVM, because it has no notion of
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]844 scoping in this sense, and does not want to be tied to a language's scoping
845 rules.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]846
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]847<p>In order to handle this, the LLVM debug format uses the metadata attached to
Nick Lewyckya87014f2010-03-31 07:50:17 +0000[diff] [blame]848 llvm instructions to encode line number and scoping information. Consider
849 the following C fragment, for example:</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]850
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]851<div class="doc_code">
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]852<pre>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]8531. void foo() {
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]8542. int X = 21;
8553. int Y = 22;
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]8564. {
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]8575. int Z = 23;
8586. Z = X;
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]8597. }
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]8608. X = Y;
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]8619. }
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]862</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]863</div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]864
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]865<p>Compiled to LLVM, this function would be represented like this:</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]866
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]867<div class="doc_code">
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]868<pre>
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]869define void @foo() nounwind ssp {
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]870entry:
Bill Wendling05252352009-12-01 00:59:58 +0000[diff] [blame]871 %X = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
872 %Y = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
873 %Z = alloca i32, align 4 ; &lt;i32*&gt; [#uses=3]
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]874 %0 = bitcast i32* %X to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel7846c1e2011-02-03 00:22:17 +0000[diff] [blame]875 call void @llvm.dbg.declare(metadata !{i32 * %X}, metadata !0), !dbg !7
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]876 store i32 21, i32* %X, !dbg !8
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]877 %1 = bitcast i32* %Y to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel7846c1e2011-02-03 00:22:17 +0000[diff] [blame]878 call void @llvm.dbg.declare(metadata !{i32 * %Y}, metadata !9), !dbg !10
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]879 store i32 22, i32* %Y, !dbg !11
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]880 %2 = bitcast i32* %Z to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel7846c1e2011-02-03 00:22:17 +0000[diff] [blame]881 call void @llvm.dbg.declare(metadata !{i32 * %Z}, metadata !12), !dbg !14
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]882 store i32 23, i32* %Z, !dbg !15
Bill Wendling05252352009-12-01 00:59:58 +0000[diff] [blame]883 %tmp = load i32* %X, !dbg !16 ; &lt;i32&gt; [#uses=1]
884 %tmp1 = load i32* %Y, !dbg !16 ; &lt;i32&gt; [#uses=1]
885 %add = add nsw i32 %tmp, %tmp1, !dbg !16 ; &lt;i32&gt; [#uses=1]
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]886 store i32 %add, i32* %Z, !dbg !16
Bill Wendling05252352009-12-01 00:59:58 +0000[diff] [blame]887 %tmp2 = load i32* %Y, !dbg !17 ; &lt;i32&gt; [#uses=1]
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]888 store i32 %tmp2, i32* %X, !dbg !17
889 ret void, !dbg !18
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]890}
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]891
Devang Patel7846c1e2011-02-03 00:22:17 +0000[diff] [blame]892declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]893
894!0 = metadata !{i32 459008, metadata !1, metadata !"X",
895 metadata !3, i32 2, metadata !6}; [ DW_TAG_auto_variable ]
896!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
897!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo", metadata !"foo",
898 metadata !"foo", metadata !3, i32 1, metadata !4,
899 i1 false, i1 true}; [DW_TAG_subprogram ]
900!3 = metadata !{i32 458769, i32 0, i32 12, metadata !"foo.c",
901 metadata !"/private/tmp", metadata !"clang 1.1", i1 true,
902 i1 false, metadata !"", i32 0}; [DW_TAG_compile_unit ]
903!4 = metadata !{i32 458773, metadata !3, metadata !"", null, i32 0, i64 0, i64 0,
904 i64 0, i32 0, null, metadata !5, i32 0}; [DW_TAG_subroutine_type ]
905!5 = metadata !{null}
906!6 = metadata !{i32 458788, metadata !3, metadata !"int", metadata !3, i32 0,
907 i64 32, i64 32, i64 0, i32 0, i32 5}; [DW_TAG_base_type ]
908!7 = metadata !{i32 2, i32 7, metadata !1, null}
909!8 = metadata !{i32 2, i32 3, metadata !1, null}
910!9 = metadata !{i32 459008, metadata !1, metadata !"Y", metadata !3, i32 3,
911 metadata !6}; [ DW_TAG_auto_variable ]
912!10 = metadata !{i32 3, i32 7, metadata !1, null}
913!11 = metadata !{i32 3, i32 3, metadata !1, null}
914!12 = metadata !{i32 459008, metadata !13, metadata !"Z", metadata !3, i32 5,
915 metadata !6}; [ DW_TAG_auto_variable ]
916!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
917!14 = metadata !{i32 5, i32 9, metadata !13, null}
918!15 = metadata !{i32 5, i32 5, metadata !13, null}
919!16 = metadata !{i32 6, i32 5, metadata !13, null}
920!17 = metadata !{i32 8, i32 3, metadata !1, null}
921!18 = metadata !{i32 9, i32 1, metadata !2, null}
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]922</pre>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]923</div>
924
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]925<p>This example illustrates a few important details about LLVM debugging
926 information. In particular, it shows how the <tt>llvm.dbg.declare</tt>
927 intrinsic and location information, which are attached to an instruction,
928 are applied together to allow a debugger to analyze the relationship between
929 statements, variable definitions, and the code used to implement the
930 function.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]931
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]932<div class="doc_code">
Bill Wendling05252352009-12-01 00:59:58 +0000[diff] [blame]933<pre>
Devang Patel7846c1e2011-02-03 00:22:17 +0000[diff] [blame]934call void @llvm.dbg.declare(metadata, metadata !0), !dbg !7
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]935</pre>
936</div>
937
938<p>The first intrinsic
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]939 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]940 encodes debugging information for the variable <tt>X</tt>. The metadata
941 <tt>!dbg !7</tt> attached to the intrinsic provides scope information for the
942 variable <tt>X</tt>.</p>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]943
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]944<div class="doc_code">
945<pre>
946!7 = metadata !{i32 2, i32 7, metadata !1, null}
947!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
948!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo",
949 metadata !"foo", metadata !"foo", metadata !3, i32 1,
950 metadata !4, i1 false, i1 true}; [DW_TAG_subprogram ]
951</pre>
952</div>
953
954<p>Here <tt>!7</tt> is metadata providing location information. It has four
955 fields: line number, column number, scope, and original scope. The original
956 scope represents inline location if this instruction is inlined inside a
957 caller, and is null otherwise. In this example, scope is encoded by
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]958 <tt>!1</tt>. <tt>!1</tt> represents a lexical block inside the scope
959 <tt>!2</tt>, where <tt>!2</tt> is a
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]960 <a href="#format_subprograms">subprogram descriptor</a>. This way the
961 location information attached to the intrinsics indicates that the
962 variable <tt>X</tt> is declared at line number 2 at a function level scope in
963 function <tt>foo</tt>.</p>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]964
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]965<p>Now lets take another example.</p>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]966
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]967<div class="doc_code">
Bill Wendling05252352009-12-01 00:59:58 +0000[diff] [blame]968<pre>
Devang Patel7846c1e2011-02-03 00:22:17 +0000[diff] [blame]969call void @llvm.dbg.declare(metadata, metadata !12), !dbg !14
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]970</pre>
971</div>
972
973<p>The second intrinsic
Devang Patel4da997b2009-11-25 23:28:01 +0000[diff] [blame]974 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]975 encodes debugging information for variable <tt>Z</tt>. The metadata
976 <tt>!dbg !14</tt> attached to the intrinsic provides scope information for
977 the variable <tt>Z</tt>.</p>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]978
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]979<div class="doc_code">
980<pre>
981!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
982!14 = metadata !{i32 5, i32 9, metadata !13, null}
983</pre>
984</div>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]985
John Criswell2a4b0802010-03-17 15:01:50 +0000[diff] [blame]986<p>Here <tt>!14</tt> indicates that <tt>Z</tt> is declared at line number 5 and
Bill Wendling991b84e2009-12-01 00:53:11 +0000[diff] [blame]987 column number 9 inside of lexical scope <tt>!13</tt>. The lexical scope
988 itself resides inside of lexical scope <tt>!1</tt> described above.</p>
989
990<p>The scope information attached with each instruction provides a
991 straightforward way to find instructions covered by a scope.</p>
992
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]993</div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]994
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]995</div>
996
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]997<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]998<h2>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]999 <a name="ccxx_frontend">C/C++ front-end specific debug information</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1000</h2>
Misha Brukmancda6a9b2004-12-09 20:27:37 +0000[diff] [blame]1001<!-- *********************************************************************** -->
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1002
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1003<div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1004
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]1005<p>The C and C++ front-ends represent information about the program in a format
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1006 that is effectively identical
1007 to <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3.0</a> in
1008 terms of information content. This allows code generators to trivially
1009 support native debuggers by generating standard dwarf information, and
1010 contains enough information for non-dwarf targets to translate it as
1011 needed.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1012
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1013<p>This section describes the forms used to represent C and C++ programs. Other
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1014 languages could pattern themselves after this (which itself is tuned to
1015 representing programs in the same way that DWARF 3 does), or they could
1016 choose to provide completely different forms if they don't fit into the DWARF
1017 model. As support for debugging information gets added to the various LLVM
1018 source-language front-ends, the information used should be documented
1019 here.</p>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1020
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1021<p>The following sections provide examples of various C/C++ constructs and the
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1022 debug information that would best describe those constructs.</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1023
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1024<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1025<h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1026 <a name="ccxx_compile_units">C/C++ source file information</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1027</h3>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1028
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1029<div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1030
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1031<p>Given the source files <tt>MySource.cpp</tt> and <tt>MyHeader.h</tt> located
1032 in the directory <tt>/Users/mine/sources</tt>, the following code:</p>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]1033
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1034<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1035<pre>
1036#include "MyHeader.h"
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]1037
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1038int main(int argc, char *argv[]) {
1039 return 0;
1040}
1041</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1042</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]1043
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1044<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1045
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1046<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1047<pre>
1048...
1049;;
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1050;; Define the compile unit for the main source file "/Users/mine/sources/MySource.cpp".
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1051;;
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1052!2 = metadata !{
1053 i32 524305, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1054 i32 0, ;; Unused
1055 i32 4, ;; Language Id
1056 metadata !"MySource.cpp",
1057 metadata !"/Users/mine/sources",
1058 metadata !"4.2.1 (Based on Apple Inc. build 5649) (LLVM build 00)",
1059 i1 true, ;; Main Compile Unit
1060 i1 false, ;; Optimized compile unit
1061 metadata !"", ;; Compiler flags
1062 i32 0} ;; Runtime version
1063
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1064;;
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1065;; Define the file for the file "/Users/mine/sources/MySource.cpp".
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1066;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1067!1 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1068 i32 524329, ;; Tag
1069 metadata !"MySource.cpp",
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1070 metadata !"/Users/mine/sources",
Devang Patel4a7904d62010-07-13 16:53:20 +0000[diff] [blame]1071 metadata !2 ;; Compile unit
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1072}
1073
1074;;
1075;; Define the file for the file "/Users/mine/sources/Myheader.h"
1076;;
1077!3 = metadata !{
1078 i32 524329, ;; Tag
1079 metadata !"Myheader.h"
1080 metadata !"/Users/mine/sources",
Devang Patel4a7904d62010-07-13 16:53:20 +0000[diff] [blame]1081 metadata !2 ;; Compile unit
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1082}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1083
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1084...
1085</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1086</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1087
Devang Patel5bc1c4b2010-03-26 19:08:36 +0000[diff] [blame]1088<p>llvm::Instruction provides easy access to metadata attached with an
1089instruction. One can extract line number information encoded in LLVM IR
1090using <tt>Instruction::getMetadata()</tt> and
1091<tt>DILocation::getLineNumber()</tt>.
1092<pre>
1093 if (MDNode *N = I->getMetadata("dbg")) { // Here I is an LLVM instruction
1094 DILocation Loc(N); // DILocation is in DebugInfo.h
1095 unsigned Line = Loc.getLineNumber();
1096 StringRef File = Loc.getFilename();
1097 StringRef Dir = Loc.getDirectory();
1098 }
1099</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]1100</div>
1101
1102<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1103<h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1104 <a name="ccxx_global_variable">C/C++ global variable information</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1105</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]1106
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1107<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1108
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1109<p>Given an integer global variable declared as follows:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1110
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1111<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1112<pre>
1113int MyGlobal = 100;
1114</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1115</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1116
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1117<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1118
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1119<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1120<pre>
1121;;
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1122;; Define the global itself.
1123;;
1124%MyGlobal = global int 100
1125...
1126;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1127;; List of debug info of globals
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1128;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1129!llvm.dbg.gv = !{!0}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1130
1131;;
1132;; Define the global variable descriptor. Note the reference to the global
1133;; variable anchor and the global variable itself.
1134;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1135!0 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1136 i32 524340, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1137 i32 0, ;; Unused
1138 metadata !1, ;; Context
1139 metadata !"MyGlobal", ;; Name
1140 metadata !"MyGlobal", ;; Display Name
1141 metadata !"MyGlobal", ;; Linkage Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1142 metadata !3, ;; Compile Unit
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1143 i32 1, ;; Line Number
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1144 metadata !4, ;; Type
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1145 i1 false, ;; Is a local variable
1146 i1 true, ;; Is this a definition
1147 i32* @MyGlobal ;; The global variable
1148}
1149
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1150;;
1151;; Define the basic type of 32 bit signed integer. Note that since int is an
1152;; intrinsic type the source file is NULL and line 0.
1153;;
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1154!4 = metadata !{
1155 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1156 metadata !1, ;; Context
1157 metadata !"int", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1158 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1159 i32 0, ;; Line number
1160 i64 32, ;; Size in Bits
1161 i64 32, ;; Align in Bits
1162 i64 0, ;; Offset in Bits
1163 i32 0, ;; Flags
1164 i32 5 ;; Encoding
1165}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1166
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1167</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1168</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1169
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]1170</div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1171
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1172<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1173<h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1174 <a name="ccxx_subprogram">C/C++ function information</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1175</h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1176
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1177<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1178
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1179<p>Given a function declared as follows:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1180
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1181<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1182<pre>
1183int main(int argc, char *argv[]) {
1184 return 0;
1185}
1186</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1187</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1188
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1189<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1190
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1191<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1192<pre>
1193;;
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1194;; Define the anchor for subprograms. Note that the second field of the
1195;; anchor is 46, which is the same as the tag for subprograms
1196;; (46 = DW_TAG_subprogram.)
1197;;
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1198!6 = metadata !{
1199 i32 524334, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1200 i32 0, ;; Unused
1201 metadata !1, ;; Context
1202 metadata !"main", ;; Name
1203 metadata !"main", ;; Display name
1204 metadata !"main", ;; Linkage name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1205 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1206 i32 1, ;; Line number
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1207 metadata !4, ;; Type
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1208 i1 false, ;; Is local
Devang Patel9f738842011-04-05 22:52:06 +0000[diff] [blame]1209 i1 true, ;; Is definition
1210 i32 0, ;; Virtuality attribute, e.g. pure virtual function
1211 i32 0, ;; Index into virtual table for C++ methods
1212 i32 0, ;; Type that holds virtual table.
1213 i32 0, ;; Flags
1214 i1 false, ;; True if this function is optimized
1215 Function *, ;; Pointer to llvm::Function
1216 null ;; Function template parameters
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1217}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1218;;
1219;; Define the subprogram itself.
1220;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1221define i32 @main(i32 %argc, i8** %argv) {
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1222...
1223}
1224</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1225</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1226
1227</div>
1228
1229<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1230<h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1231 <a name="ccxx_basic_types">C/C++ basic types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1232</h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1233
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1234<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1235
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1236<p>The following are the basic type descriptors for C/C++ core types:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1237
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1238<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1239<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1240 <a name="ccxx_basic_type_bool">bool</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1241</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1242
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1243<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1244
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1245<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1246<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1247!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1248 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1249 metadata !1, ;; Context
1250 metadata !"bool", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1251 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1252 i32 0, ;; Line number
1253 i64 8, ;; Size in Bits
1254 i64 8, ;; Align in Bits
1255 i64 0, ;; Offset in Bits
1256 i32 0, ;; Flags
1257 i32 2 ;; Encoding
1258}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1259</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1260</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1261
1262</div>
1263
1264<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1265<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1266 <a name="ccxx_basic_char">char</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1267</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1268
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1269<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1270
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1271<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1272<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1273!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1274 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1275 metadata !1, ;; Context
1276 metadata !"char", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1277 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1278 i32 0, ;; Line number
1279 i64 8, ;; Size in Bits
1280 i64 8, ;; Align in Bits
1281 i64 0, ;; Offset in Bits
1282 i32 0, ;; Flags
1283 i32 6 ;; Encoding
1284}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1285</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1286</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1287
1288</div>
1289
1290<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1291<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1292 <a name="ccxx_basic_unsigned_char">unsigned char</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1293</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1294
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1295<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1296
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1297<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1298<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1299!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1300 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1301 metadata !1, ;; Context
1302 metadata !"unsigned char",
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1303 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1304 i32 0, ;; Line number
1305 i64 8, ;; Size in Bits
1306 i64 8, ;; Align in Bits
1307 i64 0, ;; Offset in Bits
1308 i32 0, ;; Flags
1309 i32 8 ;; Encoding
1310}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1311</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1312</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1313
1314</div>
1315
1316<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1317<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1318 <a name="ccxx_basic_short">short</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1319</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1320
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1321<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1322
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1323<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1324<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1325!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1326 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1327 metadata !1, ;; Context
1328 metadata !"short int",
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1329 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1330 i32 0, ;; Line number
1331 i64 16, ;; Size in Bits
1332 i64 16, ;; Align in Bits
1333 i64 0, ;; Offset in Bits
1334 i32 0, ;; Flags
1335 i32 5 ;; Encoding
1336}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1337</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1338</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1339
1340</div>
1341
1342<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1343<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1344 <a name="ccxx_basic_unsigned_short">unsigned short</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1345</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1346
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1347<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1348
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1349<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1350<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1351!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1352 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1353 metadata !1, ;; Context
1354 metadata !"short unsigned int",
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1355 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1356 i32 0, ;; Line number
1357 i64 16, ;; Size in Bits
1358 i64 16, ;; Align in Bits
1359 i64 0, ;; Offset in Bits
1360 i32 0, ;; Flags
1361 i32 7 ;; Encoding
1362}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1363</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1364</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1365
1366</div>
1367
1368<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1369<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1370 <a name="ccxx_basic_int">int</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1371</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1372
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1373<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1374
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1375<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1376<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1377!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1378 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1379 metadata !1, ;; Context
1380 metadata !"int", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1381 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1382 i32 0, ;; Line number
1383 i64 32, ;; Size in Bits
1384 i64 32, ;; Align in Bits
1385 i64 0, ;; Offset in Bits
1386 i32 0, ;; Flags
1387 i32 5 ;; Encoding
1388}
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1389</pre></div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1390
1391</div>
1392
1393<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1394<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1395 <a name="ccxx_basic_unsigned_int">unsigned int</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1396</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1397
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1398<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1399
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1400<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1401<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1402!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1403 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1404 metadata !1, ;; Context
1405 metadata !"unsigned int",
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1406 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1407 i32 0, ;; Line number
1408 i64 32, ;; Size in Bits
1409 i64 32, ;; Align in Bits
1410 i64 0, ;; Offset in Bits
1411 i32 0, ;; Flags
1412 i32 7 ;; Encoding
1413}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1414</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1415</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1416
1417</div>
1418
1419<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1420<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1421 <a name="ccxx_basic_long_long">long long</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1422</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1423
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1424<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1425
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1426<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1427<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1428!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1429 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1430 metadata !1, ;; Context
1431 metadata !"long long int",
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1432 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1433 i32 0, ;; Line number
1434 i64 64, ;; Size in Bits
1435 i64 64, ;; Align in Bits
1436 i64 0, ;; Offset in Bits
1437 i32 0, ;; Flags
1438 i32 5 ;; Encoding
1439}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1440</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1441</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1442
1443</div>
1444
1445<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1446<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1447 <a name="ccxx_basic_unsigned_long_long">unsigned long long</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1448</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1449
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1450<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1451
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1452<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1453<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1454!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1455 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1456 metadata !1, ;; Context
1457 metadata !"long long unsigned int",
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1458 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1459 i32 0, ;; Line number
1460 i64 64, ;; Size in Bits
1461 i64 64, ;; Align in Bits
1462 i64 0, ;; Offset in Bits
1463 i32 0, ;; Flags
1464 i32 7 ;; Encoding
1465}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1466</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1467</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1468
1469</div>
1470
1471<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1472<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1473 <a name="ccxx_basic_float">float</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1474</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1475
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1476<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1477
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1478<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1479<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1480!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1481 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1482 metadata !1, ;; Context
1483 metadata !"float",
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1484 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1485 i32 0, ;; Line number
1486 i64 32, ;; Size in Bits
1487 i64 32, ;; Align in Bits
1488 i64 0, ;; Offset in Bits
1489 i32 0, ;; Flags
1490 i32 4 ;; Encoding
1491}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1492</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1493</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1494
1495</div>
1496
1497<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1498<h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1499 <a name="ccxx_basic_double">double</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1500</h4>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1501
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1502<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1503
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1504<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1505<pre>
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1506!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1507 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1508 metadata !1, ;; Context
1509 metadata !"double",;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1510 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1511 i32 0, ;; Line number
1512 i64 64, ;; Size in Bits
1513 i64 64, ;; Align in Bits
1514 i64 0, ;; Offset in Bits
1515 i32 0, ;; Flags
1516 i32 4 ;; Encoding
1517}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1518</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1519</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1520
1521</div>
1522
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1523</div>
1524
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1525<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1526<h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1527 <a name="ccxx_derived_types">C/C++ derived types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1528</h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1529
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1530<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1531
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1532<p>Given the following as an example of C/C++ derived type:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1533
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1534<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1535<pre>
1536typedef const int *IntPtr;
1537</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1538</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1539
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1540<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1541
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1542<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1543<pre>
1544;;
1545;; Define the typedef "IntPtr".
1546;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1547!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1548 i32 524310, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1549 metadata !1, ;; Context
1550 metadata !"IntPtr", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1551 metadata !3, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1552 i32 0, ;; Line number
1553 i64 0, ;; Size in bits
1554 i64 0, ;; Align in bits
1555 i64 0, ;; Offset in bits
1556 i32 0, ;; Flags
1557 metadata !4 ;; Derived From type
1558}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1559
1560;;
1561;; Define the pointer type.
1562;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1563!4 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1564 i32 524303, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1565 metadata !1, ;; Context
1566 metadata !"", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1567 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1568 i32 0, ;; Line number
1569 i64 64, ;; Size in bits
1570 i64 64, ;; Align in bits
1571 i64 0, ;; Offset in bits
1572 i32 0, ;; Flags
1573 metadata !5 ;; Derived From type
1574}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1575;;
1576;; Define the const type.
1577;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1578!5 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1579 i32 524326, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1580 metadata !1, ;; Context
1581 metadata !"", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1582 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1583 i32 0, ;; Line number
1584 i64 32, ;; Size in bits
1585 i64 32, ;; Align in bits
1586 i64 0, ;; Offset in bits
1587 i32 0, ;; Flags
1588 metadata !6 ;; Derived From type
1589}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1590;;
1591;; Define the int type.
1592;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1593!6 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1594 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1595 metadata !1, ;; Context
1596 metadata !"int", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1597 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1598 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 5 ;; Encoding
1604}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1605</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1606</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1607
1608</div>
1609
1610<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1611<h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1612 <a name="ccxx_composite_types">C/C++ struct/union types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1613</h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1614
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1615<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1616
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1617<p>Given the following as an example of C/C++ struct type:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1618
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1619<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1620<pre>
1621struct Color {
1622 unsigned Red;
1623 unsigned Green;
1624 unsigned Blue;
1625};
1626</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1627</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1628
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1629<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1630
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1631<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1632<pre>
1633;;
1634;; Define basic type for unsigned int.
1635;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1636!5 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1637 i32 524324, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1638 metadata !1, ;; Context
1639 metadata !"unsigned int",
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1640 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1641 i32 0, ;; Line number
1642 i64 32, ;; Size in Bits
1643 i64 32, ;; Align in Bits
1644 i64 0, ;; Offset in Bits
1645 i32 0, ;; Flags
1646 i32 7 ;; Encoding
1647}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1648;;
1649;; Define composite type for struct Color.
1650;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1651!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1652 i32 524307, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1653 metadata !1, ;; Context
1654 metadata !"Color", ;; Name
1655 metadata !1, ;; Compile unit
1656 i32 1, ;; Line number
1657 i64 96, ;; Size in bits
1658 i64 32, ;; Align in bits
1659 i64 0, ;; Offset in bits
1660 i32 0, ;; Flags
1661 null, ;; Derived From
1662 metadata !3, ;; Elements
1663 i32 0 ;; Runtime Language
1664}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1665
1666;;
1667;; Define the Red field.
1668;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1669!4 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1670 i32 524301, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1671 metadata !1, ;; Context
1672 metadata !"Red", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1673 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1674 i32 2, ;; Line number
1675 i64 32, ;; Size in bits
1676 i64 32, ;; Align in bits
1677 i64 0, ;; Offset in bits
1678 i32 0, ;; Flags
1679 metadata !5 ;; Derived From type
1680}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1681
1682;;
1683;; Define the Green field.
1684;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1685!6 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1686 i32 524301, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1687 metadata !1, ;; Context
1688 metadata !"Green", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1689 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1690 i32 3, ;; Line number
1691 i64 32, ;; Size in bits
1692 i64 32, ;; Align in bits
1693 i64 32, ;; Offset in bits
1694 i32 0, ;; Flags
1695 metadata !5 ;; Derived From type
1696}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1697
1698;;
1699;; Define the Blue field.
1700;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1701!7 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1702 i32 524301, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1703 metadata !1, ;; Context
1704 metadata !"Blue", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1705 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1706 i32 4, ;; Line number
1707 i64 32, ;; Size in bits
1708 i64 32, ;; Align in bits
1709 i64 64, ;; Offset in bits
1710 i32 0, ;; Flags
1711 metadata !5 ;; Derived From type
1712}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1713
1714;;
1715;; Define the array of fields used by the composite type Color.
1716;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1717!3 = metadata !{metadata !4, metadata !6, metadata !7}
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1718</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1719</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1720
1721</div>
1722
1723<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1724<h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1725 <a name="ccxx_enumeration_types">C/C++ enumeration types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1726</h3>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1727
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1728<div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1729
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1730<p>Given the following as an example of C/C++ enumeration type:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1731
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1732<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1733<pre>
1734enum Trees {
1735 Spruce = 100,
1736 Oak = 200,
1737 Maple = 300
1738};
1739</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1740</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1741
Misha Brukman39dcddf2008-12-16 02:54:22 +0000[diff] [blame]1742<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1743
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1744<div class="doc_code">
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1745<pre>
1746;;
1747;; Define composite type for enum Trees
1748;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1749!2 = metadata !{
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1750 i32 524292, ;; Tag
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1751 metadata !1, ;; Context
1752 metadata !"Trees", ;; Name
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1753 metadata !1, ;; File
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1754 i32 1, ;; Line number
1755 i64 32, ;; Size in bits
1756 i64 32, ;; Align in bits
1757 i64 0, ;; Offset in bits
1758 i32 0, ;; Flags
1759 null, ;; Derived From type
1760 metadata !3, ;; Elements
1761 i32 0 ;; Runtime language
1762}
Devang Patel02aac922009-08-25 05:24:07 +0000[diff] [blame]1763
Devang Patelf08e35d2009-08-26 05:01:18 +0000[diff] [blame]1764;;
1765;; Define the array of enumerators used by composite type Trees.
1766;;
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1767!3 = metadata !{metadata !4, metadata !5, metadata !6}
1768
1769;;
1770;; Define Spruce enumerator.
1771;;
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1772!4 = metadata !{i32 524328, metadata !"Spruce", i64 100}
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1773
1774;;
1775;; Define Oak enumerator.
1776;;
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1777!5 = metadata !{i32 524328, metadata !"Oak", i64 200}
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1778
1779;;
1780;; Define Maple enumerator.
1781;;
Devang Patel59445db2010-03-09 00:44:10 +0000[diff] [blame]1782!6 = metadata !{i32 524328, metadata !"Maple", i64 300}
Devang Patel80ae3492009-08-28 23:24:31 +0000[diff] [blame]1783
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1784</pre>
Bill Wendlinge9353d72009-05-17 05:52:39 +0000[diff] [blame]1785</div>
Jim Laskey14edc932006-03-14 18:08:46 +0000[diff] [blame]1786
1787</div>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1788
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1789</div>
1790
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1791<!-- *********************************************************************** -->
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]1792
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1793<hr>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]1794<address>
1795 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1796 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]1797 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]1798 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]1799
1800 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]1801 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1802 Last modified: $Date$
Misha Brukmanf91d9942004-05-12 19:21:57 +0000[diff] [blame]1803</address>
Chris Lattner1811fca2004-01-05 05:06:33 +0000[diff] [blame]1804
1805</body>
1806</html>