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Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]6 <title>Source Level Debugging with LLVM</title>
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9<body>
10
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]11<h1>Source Level Debugging with LLVM</h1>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]12
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]13<table class="layout" style="width:100%">
14 <tr class="layout">
15 <td class="left">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]16<ul>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]17 <li><a href="#introduction">Introduction</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]18 <ol>
19 <li><a href="#phil">Philosophy behind LLVM debugging information</a></li>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]20 <li><a href="#consumers">Debug information consumers</a></li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]21 <li><a href="#debugopt">Debugging optimized code</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]22 </ol></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]23 <li><a href="#format">Debugging information format</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]24 <ol>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]25 <li><a href="#debug_info_descriptors">Debug information descriptors</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]26 <ul>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]27 <li><a href="#format_compile_units">Compile unit descriptors</a></li>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]28 <li><a href="#format_files">File descriptors</a></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]29 <li><a href="#format_global_variables">Global variable descriptors</a></li>
30 <li><a href="#format_subprograms">Subprogram descriptors</a></li>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]31 <li><a href="#format_blocks">Block descriptors</a></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]32 <li><a href="#format_basic_type">Basic type descriptors</a></li>
33 <li><a href="#format_derived_type">Derived type descriptors</a></li>
34 <li><a href="#format_composite_type">Composite type descriptors</a></li>
35 <li><a href="#format_subrange">Subrange descriptors</a></li>
36 <li><a href="#format_enumeration">Enumerator descriptors</a></li>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]37 <li><a href="#format_variables">Local variables</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]38 </ul></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]39 <li><a href="#format_common_intrinsics">Debugger intrinsic functions</a>
40 <ul>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]41 <li><a href="#format_common_declare">llvm.dbg.declare</a></li>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]42 <li><a href="#format_common_value">llvm.dbg.value</a></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]43 </ul></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]44 </ol></li>
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]45 <li><a href="#format_common_lifetime">Object lifetimes and scoping</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]46 <li><a href="#ccxx_frontend">C/C++ front-end specific debug information</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]47 <ol>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]48 <li><a href="#ccxx_compile_units">C/C++ source file information</a></li>
49 <li><a href="#ccxx_global_variable">C/C++ global variable information</a></li>
50 <li><a href="#ccxx_subprogram">C/C++ function information</a></li>
51 <li><a href="#ccxx_basic_types">C/C++ basic types</a></li>
52 <li><a href="#ccxx_derived_types">C/C++ derived types</a></li>
53 <li><a href="#ccxx_composite_types">C/C++ struct/union types</a></li>
54 <li><a href="#ccxx_enumeration_types">C/C++ enumeration types</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]55 </ol></li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]56</ul>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]57</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]58<td class="right">
Misha Brukmane849a1a2004-05-12 21:26:16 +0000[diff] [blame]59<img src="img/venusflytrap.jpg" alt="A leafy and green bug eater" width="247"
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]60height="369">
61</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]62</tr></table>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]63
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]64<div class="doc_author">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]65 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
Jim Laskeyc760a922007-03-14 19:32:21 +0000[diff] [blame]66 and <a href="mailto:jlaskey@mac.com">Jim Laskey</a></p>
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]67</div>
68
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]69
70<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]71<h2><a name="introduction">Introduction</a></h2>
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]72<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]73
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]74<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]75
76<p>This document is the central repository for all information pertaining to
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]77 debug information in LLVM. It describes the <a href="#format">actual format
78 that the LLVM debug information</a> takes, which is useful for those
79 interested in creating front-ends or dealing directly with the information.
Chris Lattner8ad2f982009-07-18 21:47:15 +0000[diff] [blame]80 Further, this document provides specific examples of what debug information
Chris Lattner89940752011-01-18 06:12:10 +0000[diff] [blame]81 for C/C++ looks like.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]82
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]83<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]84<h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]85 <a name="phil">Philosophy behind LLVM debugging information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]86</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]87
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]88<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]89
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]90<p>The idea of the LLVM debugging information is to capture how the important
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]91 pieces of the source-language's Abstract Syntax Tree map onto LLVM code.
92 Several design aspects have shaped the solution that appears here. The
93 important ones are:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]94
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]95<ul>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]96 <li>Debugging information should have very little impact on the rest of the
97 compiler. No transformations, analyses, or code generators should need to
98 be modified because of debugging information.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]99
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]100 <li>LLVM optimizations should interact in <a href="#debugopt">well-defined and
101 easily described ways</a> with the debugging information.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]102
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]103 <li>Because LLVM is designed to support arbitrary programming languages,
104 LLVM-to-LLVM tools should not need to know anything about the semantics of
105 the source-level-language.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]106
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]107 <li>Source-level languages are often <b>widely</b> different from one another.
108 LLVM should not put any restrictions of the flavor of the source-language,
109 and the debugging information should work with any language.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]110
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]111 <li>With code generator support, it should be possible to use an LLVM compiler
112 to compile a program to native machine code and standard debugging
113 formats. This allows compatibility with traditional machine-code level
114 debuggers, like GDB or DBX.</li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]115</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]116
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]117<p>The approach used by the LLVM implementation is to use a small set
118 of <a href="#format_common_intrinsics">intrinsic functions</a> to define a
119 mapping between LLVM program objects and the source-level objects. The
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]120 description of the source-level program is maintained in LLVM metadata
121 in an <a href="#ccxx_frontend">implementation-defined format</a>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]122 (the C/C++ front-end currently uses working draft 7 of
123 the <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3
124 standard</a>).</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]125
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]126<p>When a program is being debugged, a debugger interacts with the user and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]127 turns the stored debug information into source-language specific information.
128 As such, a debugger must be aware of the source-language, and is thus tied to
129 a specific language or family of languages.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]130
131</div>
132
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]133<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]134<h3>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]135 <a name="consumers">Debug information consumers</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]136</h3>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]137
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]138<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]139
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]140<p>The role of debug information is to provide meta information normally
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]141 stripped away during the compilation process. This meta information provides
142 an LLVM user a relationship between generated code and the original program
143 source code.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]144
Chris Lattnerc3107782010-04-05 04:11:11 +0000[diff] [blame]145<p>Currently, debug information is consumed by DwarfDebug to produce dwarf
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]146 information used by the gdb debugger. Other targets could use the same
147 information to produce stabs or other debug forms.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]148
149<p>It would also be reasonable to use debug information to feed profiling tools
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]150 for analysis of generated code, or, tools for reconstructing the original
151 source from generated code.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]152
153<p>TODO - expound a bit more.</p>
154
155</div>
156
157<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]158<h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]159 <a name="debugopt">Debugging optimized code</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]160</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]161
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]162<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]163
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]164<p>An extremely high priority of LLVM debugging information is to make it
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]165 interact well with optimizations and analysis. In particular, the LLVM debug
166 information provides the following guarantees:</p>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]167
168<ul>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]169 <li>LLVM debug information <b>always provides information to accurately read
170 the source-level state of the program</b>, regardless of which LLVM
171 optimizations have been run, and without any modification to the
172 optimizations themselves. However, some optimizations may impact the
173 ability to modify the current state of the program with a debugger, such
174 as setting program variables, or calling functions that have been
175 deleted.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]176
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]177 <li>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 Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]182
Bill Wendling48839d92009-05-17 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 Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]188
Bill Wendling48839d92009-05-17 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 Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]193
Bill Wendling48839d92009-05-17 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 Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]198</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]199
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]200<p>Basically, the debug information allows you to compile a program with
Bill Wendling48839d92009-05-17 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 Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]208
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]209<p><a href="TestingGuide.html#quicktestsuite">LLVM test suite</a> provides a
Bill Wendling48839d92009-05-17 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 Patela5c05aa2008-11-21 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 Wendling48839d92009-05-17 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 Patela5c05aa2008-11-21 19:35:57 +0000[diff] [blame]224
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]225</div>
226
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]227</div>
228
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]229<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]230<h2>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]231 <a name="format">Debugging information format</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]232</h2>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]233<!-- *********************************************************************** -->
234
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]235<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]236
237<p>LLVM debugging information has been carefully designed to make it possible
Bill Wendling48839d92009-05-17 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 Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]240 particular, the use of metadata avoids duplicated debugging information from
Devang Patele4b27562009-08-28 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 Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]244
245<p>To do this, most of the debugging information (descriptors for types,
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]246 variables, functions, source files, etc) is inserted by the language
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]247 front-end in the form of LLVM metadata. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]248
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]249<p>Debug information is designed to be agnostic about the target debugger and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]250 debugging information representation (e.g. DWARF/Stabs/etc). It uses a
Devang Patele4b27562009-08-28 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 Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]255
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]256<p>To provide basic functionality, the LLVM debugger does have to make some
Bill Wendling48839d92009-05-17 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 Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]259 exist are <a href="#format_files">source files</a>,
Bill Wendling48839d92009-05-17 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 Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]263
264<p>This section of the documentation first describes the representation aspects
Bill Wendling48839d92009-05-17 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 Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]267
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]268<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]269<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]270 <a name="debug_info_descriptors">Debug information descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]271</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]272
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]273<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]274
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]275<p>In consideration of the complexity and volume of debug information, LLVM
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]276 provides a specification for well formed debug descriptors. </p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]277
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]278<p>Consumers of LLVM debug information expect the descriptors for program
Bill Wendling48839d92009-05-17 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 Kramer8040cd32009-10-12 14:46:08 +0000[diff] [blame]286 the range 0x1000 through 0x2000 (there is a defined enum DW_TAG_user_base =
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]287 0x1000.)</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]288
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]289<p>The fields of debug descriptors used internally by LLVM
Nick Lewycky655fd032010-03-31 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 Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]292
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]293<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]294<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]295!1 = metadata !{
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]296 i32, ;; A tag
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]297 ...
298}
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]299</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]300</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]301
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]302<p><a name="LLVMDebugVersion">The first field of a descriptor is always an
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]303 <tt>i32</tt> containing a tag value identifying the content of the
Bill Wendling48839d92009-05-17 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 Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]308 with the current debug version (LLVMDebugVersion = 8 &lt;&lt; 16 or 0x80000 or
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]309 524288.)</a></p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]310
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]311<p>The details of the various descriptors follow.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]312
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]313<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]314<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]315 <a name="format_compile_units">Compile unit descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]316</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]317
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]318<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]319
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]320<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]321<pre>
Devang Patele4b27562009-08-28 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 Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]334}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]335</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]336</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]337
Bill Wendling48839d92009-05-17 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 Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]343
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]344<p>Compile unit descriptors provide the root context for objects declared in a
Devang Patel464f4ef2011-05-03 16:18:28 +0000[diff] [blame]345 specific compilation unit. File descriptors are defined using this context.
346 These descriptors are collected by a named metadata
347 <tt>!llvm.dbg.cu</tt>.
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]348
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]349</div>
350
351<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]352<h4>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]353 <a name="format_files">File descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]354</h4>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]355
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]356<div>
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]357
358<div class="doc_code">
359<pre>
360!0 = metadata !{
361 i32, ;; Tag = 41 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
362 ;; (DW_TAG_file_type)
363 metadata, ;; Source file name
364 metadata, ;; Source file directory (includes trailing slash)
365 metadata ;; Reference to compile unit where defined
366}
367</pre>
368</div>
369
John Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]370<p>These descriptors contain information for a file. Global variables and top
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]371 level functions would be defined using this context.k File descriptors also
372 provide context for source line correspondence. </p>
373
374<p>Each input file is encoded as a separate file descriptor in LLVM debugging
375 information output. Each file descriptor would be defined using a
376 compile unit. </p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]377
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]378</div>
379
380<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]381<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]382 <a name="format_global_variables">Global variable descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]383</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]384
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]385<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]386
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]387<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]388<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]389!1 = metadata !{
390 i32, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
391 ;; (DW_TAG_variable)
392 i32, ;; Unused field.
393 metadata, ;; Reference to context descriptor
394 metadata, ;; Name
395 metadata, ;; Display name (fully qualified C++ name)
396 metadata, ;; MIPS linkage name (for C++)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]397 metadata, ;; Reference to file where defined
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]398 i32, ;; Line number where defined
399 metadata, ;; Reference to type descriptor
400 i1, ;; True if the global is local to compile unit (static)
401 i1, ;; True if the global is defined in the compile unit (not extern)
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]402 {}* ;; Reference to the global variable
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]403}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]404</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]405</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]406
407<p>These descriptors provide debug information about globals variables. The
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]408provide details such as name, type and where the variable is defined. All
409global variables are collected by named metadata <tt>!llvm.dbg.gv</tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]410
411</div>
412
413<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]414<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]415 <a name="format_subprograms">Subprogram descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]416</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]417
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]418<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]419
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]420<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]421<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]422!2 = metadata !{
423 i32, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
424 ;; (DW_TAG_subprogram)
425 i32, ;; Unused field.
426 metadata, ;; Reference to context descriptor
427 metadata, ;; Name
428 metadata, ;; Display name (fully qualified C++ name)
429 metadata, ;; MIPS linkage name (for C++)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]430 metadata, ;; Reference to file where defined
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]431 i32, ;; Line number where defined
432 metadata, ;; Reference to type descriptor
433 i1, ;; True if the global is local to compile unit (static)
Devang Patel5e06bb82011-04-22 23:10:17 +0000[diff] [blame]434 i1, ;; True if the global is defined in the compile unit (not extern)
435 i32, ;; Virtuality, e.g. dwarf::DW_VIRTUALITY__virtual
436 i32, ;; Index into a virtual function
Devang Patel80ecc152010-06-04 22:49:55 +0000[diff] [blame]437 metadata, ;; indicates which base type contains the vtable pointer for the
438 ;; derived class
Devang Patel5e06bb82011-04-22 23:10:17 +0000[diff] [blame]439 i1, ;; isArtificial
440 i1, ;; isOptimized
441 Function *,;; Pointer to LLVM function
442 metadata, ;; Lists function template parameters
443 metadata ;; Function declaration descriptor
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]444}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]445</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]446</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]447
448<p>These descriptors provide debug information about functions, methods and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]449 subprograms. They provide details such as name, return types and the source
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]450 location where the subprogram is defined.
451 All subprogram descriptors are collected by a named metadata
452 <tt>!llvm.dbg.sp</tt>.
453</p>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]454
455</div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]456
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]457<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]458<h4>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]459 <a name="format_blocks">Block descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]460</h4>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]461
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]462<div>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]463
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]464<div class="doc_code">
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]465<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]466!3 = metadata !{
Devang Patelc79dda22010-10-04 16:51:59 +0000[diff] [blame]467 i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
Devang Patel7f271fc2010-10-01 22:45:00 +0000[diff] [blame]468 metadata,;; Reference to context descriptor
469 i32, ;; Line number
Devang Patel90d81f12011-03-08 16:25:29 +0000[diff] [blame]470 i32, ;; Column number
471 metadata,;; Reference to source file
472 i32 ;; Unique ID to identify blocks from a template function
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]473}
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]474</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]475</div>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]476
477<p>These descriptors provide debug information about nested blocks within a
Devang Patel7f271fc2010-10-01 22:45:00 +0000[diff] [blame]478 subprogram. The line number and column numbers are used to dinstinguish
479 two lexical blocks at same depth. </p>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]480
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]481</div>
482
483<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]484<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]485 <a name="format_basic_type">Basic type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]486</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]487
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]488<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]489
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]490<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]491<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]492!4 = metadata !{
493 i32, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
494 ;; (DW_TAG_base_type)
495 metadata, ;; Reference to context (typically a compile unit)
496 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]497 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]498 i32, ;; Line number where defined (may be 0)
499 i64, ;; Size in bits
500 i64, ;; Alignment in bits
501 i64, ;; Offset in bits
502 i32, ;; Flags
503 i32 ;; DWARF type encoding
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]504}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]505</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]506</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]507
508<p>These descriptors define primitive types used in the code. Example int, bool
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]509 and float. The context provides the scope of the type, which is usually the
510 top level. Since basic types are not usually user defined the compile unit
511 and line number can be left as NULL and 0. The size, alignment and offset
512 are expressed in bits and can be 64 bit values. The alignment is used to
513 round the offset when embedded in a
514 <a href="#format_composite_type">composite type</a> (example to keep float
515 doubles on 64 bit boundaries.) The offset is the bit offset if embedded in
516 a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]517
518<p>The type encoding provides the details of the type. The values are typically
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]519 one of the following:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]520
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]521<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]522<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]523DW_ATE_address = 1
524DW_ATE_boolean = 2
525DW_ATE_float = 4
526DW_ATE_signed = 5
527DW_ATE_signed_char = 6
528DW_ATE_unsigned = 7
529DW_ATE_unsigned_char = 8
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]530</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]531</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]532
533</div>
534
535<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]536<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]537 <a name="format_derived_type">Derived type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]538</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]539
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]540<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]541
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]542<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]543<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]544!5 = metadata !{
545 i32, ;; Tag (see below)
546 metadata, ;; Reference to context
547 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]548 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]549 i32, ;; Line number where defined (may be 0)
Devang Patel0ffd10b2010-10-01 19:19:30 +0000[diff] [blame]550 i64, ;; Size in bits
551 i64, ;; Alignment in bits
552 i64, ;; Offset in bits
Devang Patele9db5e22011-04-16 00:11:51 +0000[diff] [blame]553 metadata, ;; Reference to type derived from
554 metadata, ;; (optional) Name of the Objective C property assoicated with
555 ;; Objective-C an ivar
556 metadata, ;; (optional) Name of the Objective C property getter selector.
557 metadata, ;; (optional) Name of the Objective C property setter selector.
558 i32 ;; (optional) Objective C property attributes.
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]559}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]560</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]561</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]562
563<p>These descriptors are used to define types derived from other types. The
564value of the tag varies depending on the meaning. The following are possible
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]565tag values:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]566
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]567<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]568<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]569DW_TAG_formal_parameter = 5
570DW_TAG_member = 13
571DW_TAG_pointer_type = 15
572DW_TAG_reference_type = 16
573DW_TAG_typedef = 22
574DW_TAG_const_type = 38
575DW_TAG_volatile_type = 53
576DW_TAG_restrict_type = 55
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]577</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]578</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]579
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]580<p><tt>DW_TAG_member</tt> is used to define a member of
581 a <a href="#format_composite_type">composite type</a>
582 or <a href="#format_subprograms">subprogram</a>. The type of the member is
583 the <a href="#format_derived_type">derived
584 type</a>. <tt>DW_TAG_formal_parameter</tt> is used to define a member which
585 is a formal argument of a subprogram.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]586
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]587<p><tt>DW_TAG_typedef</tt> is used to provide a name for the derived type.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]588
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]589<p><tt>DW_TAG_pointer_type</tt>,<tt>DW_TAG_reference_type</tt>,
590 <tt>DW_TAG_const_type</tt>, <tt>DW_TAG_volatile_type</tt>
591 and <tt>DW_TAG_restrict_type</tt> are used to qualify
592 the <a href="#format_derived_type">derived type</a>. </p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]593
594<p><a href="#format_derived_type">Derived type</a> location can be determined
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]595 from the compile unit and line number. The size, alignment and offset are
596 expressed in bits and can be 64 bit values. The alignment is used to round
597 the offset when embedded in a <a href="#format_composite_type">composite
598 type</a> (example to keep float doubles on 64 bit boundaries.) The offset is
599 the bit offset if embedded in a <a href="#format_composite_type">composite
600 type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]601
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]602<p>Note that the <tt>void *</tt> type is expressed as a type derived from NULL.
603</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]604
605</div>
606
607<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]608<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]609 <a name="format_composite_type">Composite type descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]610</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]611
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]612<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]613
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]614<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]615<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]616!6 = metadata !{
617 i32, ;; Tag (see below)
618 metadata, ;; Reference to context
619 metadata, ;; Name (may be "" for anonymous types)
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]620 metadata, ;; Reference to file where defined (may be NULL)
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]621 i32, ;; Line number where defined (may be 0)
622 i64, ;; Size in bits
623 i64, ;; Alignment in bits
624 i64, ;; Offset in bits
625 i32, ;; Flags
626 metadata, ;; Reference to type derived from
627 metadata, ;; Reference to array of member descriptors
628 i32 ;; Runtime languages
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]629}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]630</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]631</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]632
633<p>These descriptors are used to define types that are composed of 0 or more
634elements. The value of the tag varies depending on the meaning. The following
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]635are possible tag values:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]636
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]637<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]638<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]639DW_TAG_array_type = 1
640DW_TAG_enumeration_type = 4
641DW_TAG_structure_type = 19
642DW_TAG_union_type = 23
643DW_TAG_vector_type = 259
Bruno Cardoso Lopesd80ddc02009-05-29 17:08:57 +0000[diff] [blame]644DW_TAG_subroutine_type = 21
645DW_TAG_inheritance = 28
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]646</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]647</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]648
Jim Laskeyf8a01a92006-06-15 20:51:43 +0000[diff] [blame]649<p>The vector flag indicates that an array type is a native packed vector.</p>
650
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]651<p>The members of array types (tag = <tt>DW_TAG_array_type</tt>) or vector types
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]652 (tag = <tt>DW_TAG_vector_type</tt>) are <a href="#format_subrange">subrange
653 descriptors</a>, each representing the range of subscripts at that level of
654 indexing.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]655
656<p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]657 <a href="#format_enumeration">enumerator descriptors</a>, each representing
Devang Patelda6eed32011-03-29 17:27:08 +0000[diff] [blame]658 the definition of enumeration value for the set. All enumeration type
659 descriptors are collected by named metadata <tt>!llvm.dbg.enum</tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]660
661<p>The members of structure (tag = <tt>DW_TAG_structure_type</tt>) or union (tag
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]662 = <tt>DW_TAG_union_type</tt>) types are any one of
663 the <a href="#format_basic_type">basic</a>,
664 <a href="#format_derived_type">derived</a>
665 or <a href="#format_composite_type">composite</a> type descriptors, each
666 representing a field member of the structure or union.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]667
Jim Laskey4a9df242006-08-21 21:21:06 +0000[diff] [blame]668<p>For C++ classes (tag = <tt>DW_TAG_structure_type</tt>), member descriptors
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]669 provide information about base classes, static members and member
670 functions. If a member is a <a href="#format_derived_type">derived type
671 descriptor</a> and has a tag of <tt>DW_TAG_inheritance</tt>, then the type
672 represents a base class. If the member of is
673 a <a href="#format_global_variables">global variable descriptor</a> then it
674 represents a static member. And, if the member is
675 a <a href="#format_subprograms">subprogram descriptor</a> then it represents
676 a member function. For static members and member
677 functions, <tt>getName()</tt> returns the members link or the C++ mangled
678 name. <tt>getDisplayName()</tt> the simplied version of the name.</p>
Jim Laskey4a9df242006-08-21 21:21:06 +0000[diff] [blame]679
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]680<p>The first member of subroutine (tag = <tt>DW_TAG_subroutine_type</tt>) type
681 elements is the return type for the subroutine. The remaining elements are
682 the formal arguments to the subroutine.</p>
Jim Laskey094ee722006-06-20 21:13:20 +0000[diff] [blame]683
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]684<p><a href="#format_composite_type">Composite type</a> location can be
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]685 determined from the compile unit and line number. The size, alignment and
686 offset are expressed in bits and can be 64 bit values. The alignment is used
687 to round the offset when embedded in
688 a <a href="#format_composite_type">composite type</a> (as an example, to keep
689 float doubles on 64 bit boundaries.) The offset is the bit offset if embedded
690 in a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]691
692</div>
693
694<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]695<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]696 <a name="format_subrange">Subrange descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]697</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]698
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]699<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]700
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]701<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]702<pre>
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]703!42 = metadata !{
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]704 i32, ;; Tag = 33 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subrange_type)
705 i64, ;; Low value
706 i64 ;; High value
707}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]708</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]709</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]710
711<p>These descriptors are used to define ranges of array subscripts for an array
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]712 <a href="#format_composite_type">composite type</a>. The low value defines
713 the lower bounds typically zero for C/C++. The high value is the upper
714 bounds. Values are 64 bit. High - low + 1 is the size of the array. If low
Devang Patel3f932a72011-04-08 23:39:38 +0000[diff] [blame]715 > high the array bounds are not included in generated debugging information.
716</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]717
718</div>
719
720<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]721<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]722 <a name="format_enumeration">Enumerator descriptors</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]723</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]724
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]725<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]726
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]727<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]728<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]729!6 = metadata !{
730 i32, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
731 ;; (DW_TAG_enumerator)
732 metadata, ;; Name
733 i64 ;; Value
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]734}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]735</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]736</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]737
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]738<p>These descriptors are used to define members of an
739 enumeration <a href="#format_composite_type">composite type</a>, it
740 associates the name to the value.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]741
742</div>
743
744<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]745<h4>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]746 <a name="format_variables">Local variables</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]747</h4>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]748
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]749<div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]750
751<div class="doc_code">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]752<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]753!7 = metadata !{
754 i32, ;; Tag (see below)
755 metadata, ;; Context
756 metadata, ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]757 metadata, ;; Reference to file where defined
Devang Patela83688f2011-03-08 16:29:40 +0000[diff] [blame]758 i32, ;; 24 bit - Line number where defined
759 ;; 8 bit - Argument number. 1 indicates 1st argument.
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]760 metadata ;; Type descriptor
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]761}
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]762</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]763</div>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]764
765<p>These descriptors are used to define variables local to a sub program. The
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]766 value of the tag depends on the usage of the variable:</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]767
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]768<div class="doc_code">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]769<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]770DW_TAG_auto_variable = 256
771DW_TAG_arg_variable = 257
772DW_TAG_return_variable = 258
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]773</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]774</div>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]775
776<p>An auto variable is any variable declared in the body of the function. An
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]777 argument variable is any variable that appears as a formal argument to the
778 function. A return variable is used to track the result of a function and
779 has no source correspondent.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]780
Jim Laskey2d395d92006-03-24 09:20:27 +0000[diff] [blame]781<p>The context is either the subprogram or block where the variable is defined.
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]782 Name the source variable name. Compile unit and line indicate where the
783 variable was defined. Type descriptor defines the declared type of the
784 variable.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]785
786</div>
787
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]788</div>
789
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]790<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]791<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]792 <a name="format_common_intrinsics">Debugger intrinsic functions</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]793</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]794
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]795<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]796
797<p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]798 provide debug information at various points in generated code.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]799
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]800<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]801<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]802 <a name="format_common_declare">llvm.dbg.declare</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]803</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]804
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]805<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]806<pre>
Devang Patel4c7c0c62010-10-01 19:22:16 +0000[diff] [blame]807 void %<a href="#format_common_declare">llvm.dbg.declare</a>(metadata, metadata)
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]808</pre>
809
Jim Laskey2d395d92006-03-24 09:20:27 +0000[diff] [blame]810<p>This intrinsic provides information about a local element (ex. variable.) The
NAKAMURA Takumi4d6deb02011-04-09 09:51:57 +0000[diff] [blame]811 first argument is metadata holding alloca for the variable. The
Devang Patele136e502011-02-01 17:22:12 +0000[diff] [blame]812 second argument is metadata containing description of the variable. </p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]813</div>
814
815<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]816<h4>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]817 <a name="format_common_value">llvm.dbg.value</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]818</h4>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]819
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]820<div>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]821<pre>
Dan Gohman3dfb3cf2010-05-28 17:07:41 +0000[diff] [blame]822 void %<a href="#format_common_value">llvm.dbg.value</a>(metadata, i64, metadata)
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]823</pre>
824
825<p>This intrinsic provides information when a user source variable is set to a
826 new value. The first argument is the new value (wrapped as metadata). The
827 second argument is the offset in the user source variable where the new value
Devang Patele136e502011-02-01 17:22:12 +0000[diff] [blame]828 is written. The third argument is metadata containing description of the
829 user source variable. </p>
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]830</div>
831
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]832</div>
833
Victor Hernandez67a1a542010-01-11 22:53:48 +0000[diff] [blame]834<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]835<h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]836 <a name="format_common_lifetime">Object lifetimes and scoping</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]837</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]838
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]839<div>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]840<p>In many languages, the local variables in functions can have their lifetimes
841 or scopes limited to a subset of a function. In the C family of languages,
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]842 for example, variables are only live (readable and writable) within the
843 source block that they are defined in. In functional languages, values are
844 only readable after they have been defined. Though this is a very obvious
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]845 concept, it is non-trivial to model in LLVM, because it has no notion of
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]846 scoping in this sense, and does not want to be tied to a language's scoping
847 rules.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]848
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]849<p>In order to handle this, the LLVM debug format uses the metadata attached to
Nick Lewycky655fd032010-03-31 07:50:17 +0000[diff] [blame]850 llvm instructions to encode line number and scoping information. Consider
851 the following C fragment, for example:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]852
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]853<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]854<pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8551. void foo() {
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8562. int X = 21;
8573. int Y = 22;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8584. {
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8595. int Z = 23;
8606. Z = X;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8617. }
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]8628. X = Y;
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8639. }
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]864</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]865</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]866
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]867<p>Compiled to LLVM, this function would be represented like this:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]868
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]869<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]870<pre>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]871define void @foo() nounwind ssp {
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]872entry:
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]873 %X = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
874 %Y = alloca i32, align 4 ; &lt;i32*&gt; [#uses=4]
875 %Z = alloca i32, align 4 ; &lt;i32*&gt; [#uses=3]
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]876 %0 = bitcast i32* %X to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]877 call void @llvm.dbg.declare(metadata !{i32 * %X}, metadata !0), !dbg !7
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]878 store i32 21, i32* %X, !dbg !8
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]879 %1 = bitcast i32* %Y to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]880 call void @llvm.dbg.declare(metadata !{i32 * %Y}, metadata !9), !dbg !10
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]881 store i32 22, i32* %Y, !dbg !11
Dan Gohmanfe47aae2010-05-28 17:13:49 +0000[diff] [blame]882 %2 = bitcast i32* %Z to {}* ; &lt;{}*&gt; [#uses=1]
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]883 call void @llvm.dbg.declare(metadata !{i32 * %Z}, metadata !12), !dbg !14
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]884 store i32 23, i32* %Z, !dbg !15
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]885 %tmp = load i32* %X, !dbg !16 ; &lt;i32&gt; [#uses=1]
886 %tmp1 = load i32* %Y, !dbg !16 ; &lt;i32&gt; [#uses=1]
887 %add = add nsw i32 %tmp, %tmp1, !dbg !16 ; &lt;i32&gt; [#uses=1]
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]888 store i32 %add, i32* %Z, !dbg !16
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]889 %tmp2 = load i32* %Y, !dbg !17 ; &lt;i32&gt; [#uses=1]
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]890 store i32 %tmp2, i32* %X, !dbg !17
891 ret void, !dbg !18
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]892}
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]893
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]894declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]895
896!0 = metadata !{i32 459008, metadata !1, metadata !"X",
897 metadata !3, i32 2, metadata !6}; [ DW_TAG_auto_variable ]
898!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
899!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo", metadata !"foo",
900 metadata !"foo", metadata !3, i32 1, metadata !4,
901 i1 false, i1 true}; [DW_TAG_subprogram ]
902!3 = metadata !{i32 458769, i32 0, i32 12, metadata !"foo.c",
903 metadata !"/private/tmp", metadata !"clang 1.1", i1 true,
904 i1 false, metadata !"", i32 0}; [DW_TAG_compile_unit ]
905!4 = metadata !{i32 458773, metadata !3, metadata !"", null, i32 0, i64 0, i64 0,
906 i64 0, i32 0, null, metadata !5, i32 0}; [DW_TAG_subroutine_type ]
907!5 = metadata !{null}
908!6 = metadata !{i32 458788, metadata !3, metadata !"int", metadata !3, i32 0,
909 i64 32, i64 32, i64 0, i32 0, i32 5}; [DW_TAG_base_type ]
910!7 = metadata !{i32 2, i32 7, metadata !1, null}
911!8 = metadata !{i32 2, i32 3, metadata !1, null}
912!9 = metadata !{i32 459008, metadata !1, metadata !"Y", metadata !3, i32 3,
913 metadata !6}; [ DW_TAG_auto_variable ]
914!10 = metadata !{i32 3, i32 7, metadata !1, null}
915!11 = metadata !{i32 3, i32 3, metadata !1, null}
916!12 = metadata !{i32 459008, metadata !13, metadata !"Z", metadata !3, i32 5,
917 metadata !6}; [ DW_TAG_auto_variable ]
918!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
919!14 = metadata !{i32 5, i32 9, metadata !13, null}
920!15 = metadata !{i32 5, i32 5, metadata !13, null}
921!16 = metadata !{i32 6, i32 5, metadata !13, null}
922!17 = metadata !{i32 8, i32 3, metadata !1, null}
923!18 = metadata !{i32 9, i32 1, metadata !2, null}
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]924</pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]925</div>
926
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]927<p>This example illustrates a few important details about LLVM debugging
928 information. In particular, it shows how the <tt>llvm.dbg.declare</tt>
929 intrinsic and location information, which are attached to an instruction,
930 are applied together to allow a debugger to analyze the relationship between
931 statements, variable definitions, and the code used to implement the
932 function.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]933
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]934<div class="doc_code">
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]935<pre>
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]936call void @llvm.dbg.declare(metadata, metadata !0), !dbg !7
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]937</pre>
938</div>
939
940<p>The first intrinsic
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]941 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]942 encodes debugging information for the variable <tt>X</tt>. The metadata
943 <tt>!dbg !7</tt> attached to the intrinsic provides scope information for the
944 variable <tt>X</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]945
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]946<div class="doc_code">
947<pre>
948!7 = metadata !{i32 2, i32 7, metadata !1, null}
949!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
950!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo",
951 metadata !"foo", metadata !"foo", metadata !3, i32 1,
952 metadata !4, i1 false, i1 true}; [DW_TAG_subprogram ]
953</pre>
954</div>
955
956<p>Here <tt>!7</tt> is metadata providing location information. It has four
957 fields: line number, column number, scope, and original scope. The original
958 scope represents inline location if this instruction is inlined inside a
959 caller, and is null otherwise. In this example, scope is encoded by
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]960 <tt>!1</tt>. <tt>!1</tt> represents a lexical block inside the scope
961 <tt>!2</tt>, where <tt>!2</tt> is a
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]962 <a href="#format_subprograms">subprogram descriptor</a>. This way the
963 location information attached to the intrinsics indicates that the
964 variable <tt>X</tt> is declared at line number 2 at a function level scope in
965 function <tt>foo</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]966
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]967<p>Now lets take another example.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]968
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]969<div class="doc_code">
Bill Wendling02216ff2009-12-01 00:59:58 +0000[diff] [blame]970<pre>
Devang Patel37280782011-02-03 00:22:17 +0000[diff] [blame]971call void @llvm.dbg.declare(metadata, metadata !12), !dbg !14
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]972</pre>
973</div>
974
975<p>The second intrinsic
Devang Patel744950d2009-11-25 23:28:01 +0000[diff] [blame]976 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]977 encodes debugging information for variable <tt>Z</tt>. The metadata
978 <tt>!dbg !14</tt> attached to the intrinsic provides scope information for
979 the variable <tt>Z</tt>.</p>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]980
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]981<div class="doc_code">
982<pre>
983!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
984!14 = metadata !{i32 5, i32 9, metadata !13, null}
985</pre>
986</div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]987
John Criswellb34500f2010-03-17 15:01:50 +0000[diff] [blame]988<p>Here <tt>!14</tt> indicates that <tt>Z</tt> is declared at line number 5 and
Bill Wendlingcf493b82009-12-01 00:53:11 +0000[diff] [blame]989 column number 9 inside of lexical scope <tt>!13</tt>. The lexical scope
990 itself resides inside of lexical scope <tt>!1</tt> described above.</p>
991
992<p>The scope information attached with each instruction provides a
993 straightforward way to find instructions covered by a scope.</p>
994
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]995</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]996
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]997</div>
998
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]999<!-- *********************************************************************** -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1000<h2>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1001 <a name="ccxx_frontend">C/C++ front-end specific debug information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1002</h2>
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]1003<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1004
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1005<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1006
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1007<p>The C and C++ front-ends represent information about the program in a format
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1008 that is effectively identical
1009 to <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3.0</a> in
1010 terms of information content. This allows code generators to trivially
1011 support native debuggers by generating standard dwarf information, and
1012 contains enough information for non-dwarf targets to translate it as
1013 needed.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1014
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1015<p>This section describes the forms used to represent C and C++ programs. Other
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1016 languages could pattern themselves after this (which itself is tuned to
1017 representing programs in the same way that DWARF 3 does), or they could
1018 choose to provide completely different forms if they don't fit into the DWARF
1019 model. As support for debugging information gets added to the various LLVM
1020 source-language front-ends, the information used should be documented
1021 here.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1022
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1023<p>The following sections provide examples of various C/C++ constructs and the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1024 debug information that would best describe those constructs.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1025
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1026<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1027<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1028 <a name="ccxx_compile_units">C/C++ source file information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1029</h3>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1030
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1031<div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1032
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1033<p>Given the source files <tt>MySource.cpp</tt> and <tt>MyHeader.h</tt> located
1034 in the directory <tt>/Users/mine/sources</tt>, the following code:</p>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1035
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1036<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1037<pre>
1038#include "MyHeader.h"
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1039
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1040int main(int argc, char *argv[]) {
1041 return 0;
1042}
1043</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1044</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1045
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1046<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1047
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1048<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1049<pre>
1050...
1051;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1052;; Define the compile unit for the main source file "/Users/mine/sources/MySource.cpp".
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1053;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1054!2 = metadata !{
1055 i32 524305, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1056 i32 0, ;; Unused
1057 i32 4, ;; Language Id
1058 metadata !"MySource.cpp",
1059 metadata !"/Users/mine/sources",
1060 metadata !"4.2.1 (Based on Apple Inc. build 5649) (LLVM build 00)",
1061 i1 true, ;; Main Compile Unit
1062 i1 false, ;; Optimized compile unit
1063 metadata !"", ;; Compiler flags
1064 i32 0} ;; Runtime version
1065
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1066;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1067;; Define the file for the file "/Users/mine/sources/MySource.cpp".
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1068;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1069!1 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1070 i32 524329, ;; Tag
1071 metadata !"MySource.cpp",
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1072 metadata !"/Users/mine/sources",
Devang Patel9fea9c22010-07-13 16:53:20 +0000[diff] [blame]1073 metadata !2 ;; Compile unit
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1074}
1075
1076;;
1077;; Define the file for the file "/Users/mine/sources/Myheader.h"
1078;;
1079!3 = metadata !{
1080 i32 524329, ;; Tag
1081 metadata !"Myheader.h"
1082 metadata !"/Users/mine/sources",
Devang Patel9fea9c22010-07-13 16:53:20 +0000[diff] [blame]1083 metadata !2 ;; Compile unit
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1084}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1085
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1086...
1087</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1088</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1089
Devang Pateld98ec5f2010-03-26 19:08:36 +0000[diff] [blame]1090<p>llvm::Instruction provides easy access to metadata attached with an
1091instruction. One can extract line number information encoded in LLVM IR
1092using <tt>Instruction::getMetadata()</tt> and
1093<tt>DILocation::getLineNumber()</tt>.
1094<pre>
1095 if (MDNode *N = I->getMetadata("dbg")) { // Here I is an LLVM instruction
1096 DILocation Loc(N); // DILocation is in DebugInfo.h
1097 unsigned Line = Loc.getLineNumber();
1098 StringRef File = Loc.getFilename();
1099 StringRef Dir = Loc.getDirectory();
1100 }
1101</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1102</div>
1103
1104<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1105<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1106 <a name="ccxx_global_variable">C/C++ global variable information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1107</h3>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1108
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1109<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1110
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1111<p>Given an integer global variable declared as follows:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1112
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1113<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1114<pre>
1115int MyGlobal = 100;
1116</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1117</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1118
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1119<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1120
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1121<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1122<pre>
1123;;
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1124;; Define the global itself.
1125;;
1126%MyGlobal = global int 100
1127...
1128;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1129;; List of debug info of globals
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1130;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1131!llvm.dbg.gv = !{!0}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1132
1133;;
1134;; Define the global variable descriptor. Note the reference to the global
1135;; variable anchor and the global variable itself.
1136;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1137!0 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1138 i32 524340, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1139 i32 0, ;; Unused
1140 metadata !1, ;; Context
1141 metadata !"MyGlobal", ;; Name
1142 metadata !"MyGlobal", ;; Display Name
1143 metadata !"MyGlobal", ;; Linkage Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1144 metadata !3, ;; Compile Unit
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1145 i32 1, ;; Line Number
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1146 metadata !4, ;; Type
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1147 i1 false, ;; Is a local variable
1148 i1 true, ;; Is this a definition
1149 i32* @MyGlobal ;; The global variable
1150}
1151
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1152;;
1153;; Define the basic type of 32 bit signed integer. Note that since int is an
1154;; intrinsic type the source file is NULL and line 0.
1155;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1156!4 = metadata !{
1157 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1158 metadata !1, ;; Context
1159 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1160 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1161 i32 0, ;; Line number
1162 i64 32, ;; Size in Bits
1163 i64 32, ;; Align in Bits
1164 i64 0, ;; Offset in Bits
1165 i32 0, ;; Flags
1166 i32 5 ;; Encoding
1167}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1168
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1169</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1170</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1171
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1172</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1173
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1174<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1175<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1176 <a name="ccxx_subprogram">C/C++ function information</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1177</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1178
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1179<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1180
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1181<p>Given a function declared as follows:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1182
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1183<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1184<pre>
1185int main(int argc, char *argv[]) {
1186 return 0;
1187}
1188</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1189</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1190
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1191<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1192
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1193<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1194<pre>
1195;;
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1196;; Define the anchor for subprograms. Note that the second field of the
1197;; anchor is 46, which is the same as the tag for subprograms
1198;; (46 = DW_TAG_subprogram.)
1199;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1200!6 = metadata !{
1201 i32 524334, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1202 i32 0, ;; Unused
1203 metadata !1, ;; Context
1204 metadata !"main", ;; Name
1205 metadata !"main", ;; Display name
1206 metadata !"main", ;; Linkage name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1207 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1208 i32 1, ;; Line number
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1209 metadata !4, ;; Type
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1210 i1 false, ;; Is local
Devang Patelda194752011-04-05 22:52:06 +0000[diff] [blame]1211 i1 true, ;; Is definition
1212 i32 0, ;; Virtuality attribute, e.g. pure virtual function
1213 i32 0, ;; Index into virtual table for C++ methods
1214 i32 0, ;; Type that holds virtual table.
1215 i32 0, ;; Flags
1216 i1 false, ;; True if this function is optimized
1217 Function *, ;; Pointer to llvm::Function
1218 null ;; Function template parameters
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1219}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1220;;
1221;; Define the subprogram itself.
1222;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1223define i32 @main(i32 %argc, i8** %argv) {
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1224...
1225}
1226</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1227</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1228
1229</div>
1230
1231<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1232<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1233 <a name="ccxx_basic_types">C/C++ basic types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1234</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1235
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1236<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1237
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1238<p>The following are the basic type descriptors for C/C++ core types:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1239
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1240<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1241<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1242 <a name="ccxx_basic_type_bool">bool</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1243</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1244
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1245<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1246
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1247<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1248<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1249!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1250 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1251 metadata !1, ;; Context
1252 metadata !"bool", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1253 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1254 i32 0, ;; Line number
1255 i64 8, ;; Size in Bits
1256 i64 8, ;; Align in Bits
1257 i64 0, ;; Offset in Bits
1258 i32 0, ;; Flags
1259 i32 2 ;; Encoding
1260}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1261</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1262</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1263
1264</div>
1265
1266<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1267<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1268 <a name="ccxx_basic_char">char</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1269</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1270
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1271<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1272
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1273<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1274<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1275!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1276 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1277 metadata !1, ;; Context
1278 metadata !"char", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1279 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1280 i32 0, ;; Line number
1281 i64 8, ;; Size in Bits
1282 i64 8, ;; Align in Bits
1283 i64 0, ;; Offset in Bits
1284 i32 0, ;; Flags
1285 i32 6 ;; Encoding
1286}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1287</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1288</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1289
1290</div>
1291
1292<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1293<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1294 <a name="ccxx_basic_unsigned_char">unsigned char</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1295</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1296
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1297<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1298
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1299<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1300<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1301!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1302 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1303 metadata !1, ;; Context
1304 metadata !"unsigned char",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1305 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1306 i32 0, ;; Line number
1307 i64 8, ;; Size in Bits
1308 i64 8, ;; Align in Bits
1309 i64 0, ;; Offset in Bits
1310 i32 0, ;; Flags
1311 i32 8 ;; Encoding
1312}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1313</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1314</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1315
1316</div>
1317
1318<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1319<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1320 <a name="ccxx_basic_short">short</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1321</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1322
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1323<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1324
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1325<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1326<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1327!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1328 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1329 metadata !1, ;; Context
1330 metadata !"short int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1331 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1332 i32 0, ;; Line number
1333 i64 16, ;; Size in Bits
1334 i64 16, ;; Align in Bits
1335 i64 0, ;; Offset in Bits
1336 i32 0, ;; Flags
1337 i32 5 ;; Encoding
1338}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1339</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1340</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1341
1342</div>
1343
1344<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1345<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1346 <a name="ccxx_basic_unsigned_short">unsigned short</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1347</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1348
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1349<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1350
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1351<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1352<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1353!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1354 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1355 metadata !1, ;; Context
1356 metadata !"short unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1357 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1358 i32 0, ;; Line number
1359 i64 16, ;; Size in Bits
1360 i64 16, ;; Align in Bits
1361 i64 0, ;; Offset in Bits
1362 i32 0, ;; Flags
1363 i32 7 ;; Encoding
1364}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1365</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1366</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1367
1368</div>
1369
1370<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1371<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1372 <a name="ccxx_basic_int">int</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1373</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1374
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1375<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1376
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1377<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1378<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1379!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1380 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1381 metadata !1, ;; Context
1382 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1383 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1384 i32 0, ;; Line number
1385 i64 32, ;; Size in Bits
1386 i64 32, ;; Align in Bits
1387 i64 0, ;; Offset in Bits
1388 i32 0, ;; Flags
1389 i32 5 ;; Encoding
1390}
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1391</pre></div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1392
1393</div>
1394
1395<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1396<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1397 <a name="ccxx_basic_unsigned_int">unsigned int</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1398</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1399
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1400<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1401
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1402<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1403<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1404!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1405 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1406 metadata !1, ;; Context
1407 metadata !"unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1408 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1409 i32 0, ;; Line number
1410 i64 32, ;; Size in Bits
1411 i64 32, ;; Align in Bits
1412 i64 0, ;; Offset in Bits
1413 i32 0, ;; Flags
1414 i32 7 ;; Encoding
1415}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1416</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1417</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1418
1419</div>
1420
1421<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1422<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1423 <a name="ccxx_basic_long_long">long long</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1424</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1425
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1426<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1427
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1428<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1429<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1430!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1431 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1432 metadata !1, ;; Context
1433 metadata !"long long int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1434 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1435 i32 0, ;; Line number
1436 i64 64, ;; Size in Bits
1437 i64 64, ;; Align in Bits
1438 i64 0, ;; Offset in Bits
1439 i32 0, ;; Flags
1440 i32 5 ;; Encoding
1441}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1442</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1443</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1444
1445</div>
1446
1447<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1448<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1449 <a name="ccxx_basic_unsigned_long_long">unsigned long long</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1450</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1451
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1452<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1453
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1454<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1455<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1456!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1457 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1458 metadata !1, ;; Context
1459 metadata !"long long unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1460 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1461 i32 0, ;; Line number
1462 i64 64, ;; Size in Bits
1463 i64 64, ;; Align in Bits
1464 i64 0, ;; Offset in Bits
1465 i32 0, ;; Flags
1466 i32 7 ;; Encoding
1467}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1468</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1469</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1470
1471</div>
1472
1473<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1474<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1475 <a name="ccxx_basic_float">float</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1476</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1477
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1478<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1479
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1480<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1481<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1482!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1483 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1484 metadata !1, ;; Context
1485 metadata !"float",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1486 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1487 i32 0, ;; Line number
1488 i64 32, ;; Size in Bits
1489 i64 32, ;; Align in Bits
1490 i64 0, ;; Offset in Bits
1491 i32 0, ;; Flags
1492 i32 4 ;; Encoding
1493}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1494</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1495</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1496
1497</div>
1498
1499<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1500<h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1501 <a name="ccxx_basic_double">double</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1502</h4>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1503
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1504<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1505
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1506<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1507<pre>
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1508!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1509 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1510 metadata !1, ;; Context
1511 metadata !"double",;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1512 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1513 i32 0, ;; Line number
1514 i64 64, ;; Size in Bits
1515 i64 64, ;; Align in Bits
1516 i64 0, ;; Offset in Bits
1517 i32 0, ;; Flags
1518 i32 4 ;; Encoding
1519}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1520</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1521</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1522
1523</div>
1524
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1525</div>
1526
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1527<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1528<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1529 <a name="ccxx_derived_types">C/C++ derived types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1530</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1531
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1532<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1533
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1534<p>Given the following as an example of C/C++ derived type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1535
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1536<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1537<pre>
1538typedef const int *IntPtr;
1539</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1540</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1541
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1542<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1543
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1544<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1545<pre>
1546;;
1547;; Define the typedef "IntPtr".
1548;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1549!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1550 i32 524310, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1551 metadata !1, ;; Context
1552 metadata !"IntPtr", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1553 metadata !3, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1554 i32 0, ;; Line number
1555 i64 0, ;; Size in bits
1556 i64 0, ;; Align in bits
1557 i64 0, ;; Offset in bits
1558 i32 0, ;; Flags
1559 metadata !4 ;; Derived From type
1560}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1561
1562;;
1563;; Define the pointer type.
1564;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1565!4 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1566 i32 524303, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1567 metadata !1, ;; Context
1568 metadata !"", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1569 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1570 i32 0, ;; Line number
1571 i64 64, ;; Size in bits
1572 i64 64, ;; Align in bits
1573 i64 0, ;; Offset in bits
1574 i32 0, ;; Flags
1575 metadata !5 ;; Derived From type
1576}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1577;;
1578;; Define the const type.
1579;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1580!5 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1581 i32 524326, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1582 metadata !1, ;; Context
1583 metadata !"", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1584 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1585 i32 0, ;; Line number
1586 i64 32, ;; Size in bits
1587 i64 32, ;; Align in bits
1588 i64 0, ;; Offset in bits
1589 i32 0, ;; Flags
1590 metadata !6 ;; Derived From type
1591}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1592;;
1593;; Define the int type.
1594;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1595!6 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1596 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1597 metadata !1, ;; Context
1598 metadata !"int", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1599 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1600 i32 0, ;; Line number
1601 i64 32, ;; Size in bits
1602 i64 32, ;; Align in bits
1603 i64 0, ;; Offset in bits
1604 i32 0, ;; Flags
1605 5 ;; Encoding
1606}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1607</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1608</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1609
1610</div>
1611
1612<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1613<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1614 <a name="ccxx_composite_types">C/C++ struct/union types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1615</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1616
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1617<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1618
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1619<p>Given the following as an example of C/C++ struct type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1620
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1621<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1622<pre>
1623struct Color {
1624 unsigned Red;
1625 unsigned Green;
1626 unsigned Blue;
1627};
1628</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1629</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1630
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1631<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1632
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1633<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1634<pre>
1635;;
1636;; Define basic type for unsigned int.
1637;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1638!5 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1639 i32 524324, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1640 metadata !1, ;; Context
1641 metadata !"unsigned int",
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1642 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1643 i32 0, ;; Line number
1644 i64 32, ;; Size in Bits
1645 i64 32, ;; Align in Bits
1646 i64 0, ;; Offset in Bits
1647 i32 0, ;; Flags
1648 i32 7 ;; Encoding
1649}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1650;;
1651;; Define composite type for struct Color.
1652;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1653!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1654 i32 524307, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1655 metadata !1, ;; Context
1656 metadata !"Color", ;; Name
1657 metadata !1, ;; Compile unit
1658 i32 1, ;; Line number
1659 i64 96, ;; Size in bits
1660 i64 32, ;; Align in bits
1661 i64 0, ;; Offset in bits
1662 i32 0, ;; Flags
1663 null, ;; Derived From
1664 metadata !3, ;; Elements
1665 i32 0 ;; Runtime Language
1666}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1667
1668;;
1669;; Define the Red field.
1670;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1671!4 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1672 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1673 metadata !1, ;; Context
1674 metadata !"Red", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1675 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1676 i32 2, ;; Line number
1677 i64 32, ;; Size in bits
1678 i64 32, ;; Align in bits
1679 i64 0, ;; Offset in bits
1680 i32 0, ;; Flags
1681 metadata !5 ;; Derived From type
1682}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1683
1684;;
1685;; Define the Green field.
1686;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1687!6 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1688 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1689 metadata !1, ;; Context
1690 metadata !"Green", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1691 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1692 i32 3, ;; Line number
1693 i64 32, ;; Size in bits
1694 i64 32, ;; Align in bits
1695 i64 32, ;; Offset in bits
1696 i32 0, ;; Flags
1697 metadata !5 ;; Derived From type
1698}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1699
1700;;
1701;; Define the Blue field.
1702;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1703!7 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1704 i32 524301, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1705 metadata !1, ;; Context
1706 metadata !"Blue", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1707 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1708 i32 4, ;; Line number
1709 i64 32, ;; Size in bits
1710 i64 32, ;; Align in bits
1711 i64 64, ;; Offset in bits
1712 i32 0, ;; Flags
1713 metadata !5 ;; Derived From type
1714}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1715
1716;;
1717;; Define the array of fields used by the composite type Color.
1718;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1719!3 = metadata !{metadata !4, metadata !6, metadata !7}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1720</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1721</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1722
1723</div>
1724
1725<!-- ======================================================================= -->
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1726<h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1727 <a name="ccxx_enumeration_types">C/C++ enumeration types</a>
NAKAMURA Takumi05d02652011-04-18 23:59:50 +0000[diff] [blame]1728</h3>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1729
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1730<div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1731
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1732<p>Given the following as an example of C/C++ enumeration type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1733
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1734<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1735<pre>
1736enum Trees {
1737 Spruce = 100,
1738 Oak = 200,
1739 Maple = 300
1740};
1741</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1742</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1743
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1744<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1745
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1746<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1747<pre>
1748;;
1749;; Define composite type for enum Trees
1750;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1751!2 = metadata !{
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1752 i32 524292, ;; Tag
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1753 metadata !1, ;; Context
1754 metadata !"Trees", ;; Name
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1755 metadata !1, ;; File
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1756 i32 1, ;; Line number
1757 i64 32, ;; Size in bits
1758 i64 32, ;; Align in bits
1759 i64 0, ;; Offset in bits
1760 i32 0, ;; Flags
1761 null, ;; Derived From type
1762 metadata !3, ;; Elements
1763 i32 0 ;; Runtime language
1764}
Devang Patel2a610c72009-08-25 05:24:07 +0000[diff] [blame]1765
Devang Patel82459882009-08-26 05:01:18 +0000[diff] [blame]1766;;
1767;; Define the array of enumerators used by composite type Trees.
1768;;
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1769!3 = metadata !{metadata !4, metadata !5, metadata !6}
1770
1771;;
1772;; Define Spruce enumerator.
1773;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1774!4 = metadata !{i32 524328, metadata !"Spruce", i64 100}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1775
1776;;
1777;; Define Oak enumerator.
1778;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1779!5 = metadata !{i32 524328, metadata !"Oak", i64 200}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1780
1781;;
1782;; Define Maple enumerator.
1783;;
Devang Patel4b945502010-03-09 00:44:10 +0000[diff] [blame]1784!6 = metadata !{i32 524328, metadata !"Maple", i64 300}
Devang Patele4b27562009-08-28 23:24:31 +0000[diff] [blame]1785
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1786</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame]1787</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1788
1789</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1790
NAKAMURA Takumif5af6ad2011-04-23 00:30:22 +0000[diff] [blame]1791</div>
1792
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1793<!-- *********************************************************************** -->
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1794
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1795<hr>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1796<address>
1797 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]1798 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1799 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]1800 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1801
1802 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumib9a33632011-04-09 02:13:37 +0000[diff] [blame]1803 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1804 Last modified: $Date$
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1805</address>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1806
1807</body>
1808</html>