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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 48839d9973f8f327bbd07babf62ac67f37010014 / . / docs / SourceLevelDebugging.html
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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
11<div class="doc_title">Source Level Debugging with LLVM</div>
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_anchors">Anchor descriptors</a></li>
28 <li><a href="#format_compile_units">Compile unit descriptors</a></li>
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>
41 <li><a href="#format_common_stoppoint">llvm.dbg.stoppoint</a></li>
42 <li><a href="#format_common_func_start">llvm.dbg.func.start</a></li>
43 <li><a href="#format_common_region_start">llvm.dbg.region.start</a></li>
44 <li><a href="#format_common_region_end">llvm.dbg.region.end</a></li>
45 <li><a href="#format_common_declare">llvm.dbg.declare</a></li>
46 </ul></li>
47 <li><a href="#format_common_stoppoints">Representing stopping points in the
48 source program</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]49 </ol></li>
50 <li><a href="#ccxx_frontend">C/C++ front-end specific debug information</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]51 <ol>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]52 <li><a href="#ccxx_compile_units">C/C++ source file information</a></li>
53 <li><a href="#ccxx_global_variable">C/C++ global variable information</a></li>
54 <li><a href="#ccxx_subprogram">C/C++ function information</a></li>
55 <li><a href="#ccxx_basic_types">C/C++ basic types</a></li>
56 <li><a href="#ccxx_derived_types">C/C++ derived types</a></li>
57 <li><a href="#ccxx_composite_types">C/C++ struct/union types</a></li>
58 <li><a href="#ccxx_enumeration_types">C/C++ enumeration types</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]59 </ol></li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]60</ul>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]61</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]62<td class="right">
Misha Brukmane849a1a2004-05-12 21:26:16 +0000[diff] [blame]63<img src="img/venusflytrap.jpg" alt="A leafy and green bug eater" width="247"
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]64height="369">
65</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]66</tr></table>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]67
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]68<div class="doc_author">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]69 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
Jim Laskeyc760a922007-03-14 19:32:21 +0000[diff] [blame]70 and <a href="mailto:jlaskey@mac.com">Jim Laskey</a></p>
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]71</div>
72
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]73
74<!-- *********************************************************************** -->
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]75<div class="doc_section"><a name="introduction">Introduction</a></div>
76<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]77
78<div class="doc_text">
79
80<p>This document is the central repository for all information pertaining to
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]81 debug information in LLVM. It describes the <a href="#format">actual format
82 that the LLVM debug information</a> takes, which is useful for those
83 interested in creating front-ends or dealing directly with the information.
84 Further, this document provides specifc examples of what debug information
85 for C/C++.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]86
87</div>
88
89<!-- ======================================================================= -->
90<div class="doc_subsection">
91 <a name="phil">Philosophy behind LLVM debugging information</a>
92</div>
93
94<div class="doc_text">
95
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]96<p>The idea of the LLVM debugging information is to capture how the important
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]97 pieces of the source-language's Abstract Syntax Tree map onto LLVM code.
98 Several design aspects have shaped the solution that appears here. The
99 important ones are:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]100
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]101<ul>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]102 <li>Debugging information should have very little impact on the rest of the
103 compiler. No transformations, analyses, or code generators should need to
104 be modified because of debugging information.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]105
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]106 <li>LLVM optimizations should interact in <a href="#debugopt">well-defined and
107 easily described ways</a> with the debugging information.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]108
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]109 <li>Because LLVM is designed to support arbitrary programming languages,
110 LLVM-to-LLVM tools should not need to know anything about the semantics of
111 the source-level-language.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]112
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]113 <li>Source-level languages are often <b>widely</b> different from one another.
114 LLVM should not put any restrictions of the flavor of the source-language,
115 and the debugging information should work with any language.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]116
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]117 <li>With code generator support, it should be possible to use an LLVM compiler
118 to compile a program to native machine code and standard debugging
119 formats. This allows compatibility with traditional machine-code level
120 debuggers, like GDB or DBX.</li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]121</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]122
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]123<p>The approach used by the LLVM implementation is to use a small set
124 of <a href="#format_common_intrinsics">intrinsic functions</a> to define a
125 mapping between LLVM program objects and the source-level objects. The
126 description of the source-level program is maintained in LLVM global
127 variables in an <a href="#ccxx_frontend">implementation-defined format</a>
128 (the C/C++ front-end currently uses working draft 7 of
129 the <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3
130 standard</a>).</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]131
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]132<p>When a program is being debugged, a debugger interacts with the user and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]133 turns the stored debug information into source-language specific information.
134 As such, a debugger must be aware of the source-language, and is thus tied to
135 a specific language or family of languages.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]136
137</div>
138
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]139<!-- ======================================================================= -->
140<div class="doc_subsection">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]141 <a name="consumers">Debug information consumers</a>
142</div>
143
144<div class="doc_text">
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]145
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]146<p>The role of debug information is to provide meta information normally
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]147 stripped away during the compilation process. This meta information provides
148 an LLVM user a relationship between generated code and the original program
149 source code.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]150
151<p>Currently, debug information is consumed by the DwarfWriter to produce dwarf
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]152 information used by the gdb debugger. Other targets could use the same
153 information to produce stabs or other debug forms.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]154
155<p>It would also be reasonable to use debug information to feed profiling tools
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]156 for analysis of generated code, or, tools for reconstructing the original
157 source from generated code.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]158
159<p>TODO - expound a bit more.</p>
160
161</div>
162
163<!-- ======================================================================= -->
164<div class="doc_subsection">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]165 <a name="debugopt">Debugging optimized code</a>
166</div>
167
168<div class="doc_text">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]169
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]170<p>An extremely high priority of LLVM debugging information is to make it
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]171 interact well with optimizations and analysis. In particular, the LLVM debug
172 information provides the following guarantees:</p>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]173
174<ul>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]175 <li>LLVM debug information <b>always provides information to accurately read
176 the source-level state of the program</b>, regardless of which LLVM
177 optimizations have been run, and without any modification to the
178 optimizations themselves. However, some optimizations may impact the
179 ability to modify the current state of the program with a debugger, such
180 as setting program variables, or calling functions that have been
181 deleted.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]182
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]183 <li>LLVM optimizations gracefully interact with debugging information. If
184 they are not aware of debug information, they are automatically disabled
185 as necessary in the cases that would invalidate the debug info. This
186 retains the LLVM features, making it easy to write new
187 transformations.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]188
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]189 <li>As desired, LLVM optimizations can be upgraded to be aware of the LLVM
190 debugging information, allowing them to update the debugging information
191 as they perform aggressive optimizations. This means that, with effort,
192 the LLVM optimizers could optimize debug code just as well as non-debug
193 code.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]194
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]195 <li>LLVM debug information does not prevent many important optimizations from
196 happening (for example inlining, basic block reordering/merging/cleanup,
197 tail duplication, etc), further reducing the amount of the compiler that
198 eventually is "aware" of debugging information.</li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]199
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]200 <li>LLVM debug information is automatically optimized along with the rest of
201 the program, using existing facilities. For example, duplicate
202 information is automatically merged by the linker, and unused information
203 is automatically removed.</li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]204</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]205
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]206<p>Basically, the debug information allows you to compile a program with
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]207 "<tt>-O0 -g</tt>" and get full debug information, allowing you to arbitrarily
208 modify the program as it executes from a debugger. Compiling a program with
209 "<tt>-O3 -g</tt>" gives you full debug information that is always available
210 and accurate for reading (e.g., you get accurate stack traces despite tail
211 call elimination and inlining), but you might lose the ability to modify the
212 program and call functions where were optimized out of the program, or
213 inlined away completely.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]214
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]215<p><a href="TestingGuide.html#quicktestsuite">LLVM test suite</a> provides a
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]216 framework to test optimizer's handling of debugging information. It can be
217 run like this:</p>
Devang Patela5c05aa2008-11-21 19:35:57 +0000[diff] [blame]218
219<div class="doc_code">
220<pre>
221% cd llvm/projects/test-suite/MultiSource/Benchmarks # or some other level
222% make TEST=dbgopt
223</pre>
224</div>
225
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]226<p>This will test impact of debugging information on optimization passes. If
227 debugging information influences optimization passes then it will be reported
228 as a failure. See <a href="TestingGuide.html">TestingGuide</a> for more
229 information on LLVM test infrastructure and how to run various tests.</p>
Devang Patela5c05aa2008-11-21 19:35:57 +0000[diff] [blame]230
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]231</div>
232
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]233<!-- *********************************************************************** -->
234<div class="doc_section">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]235 <a name="format">Debugging information format</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]236</div>
237<!-- *********************************************************************** -->
238
239<div class="doc_text">
240
241<p>LLVM debugging information has been carefully designed to make it possible
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]242 for the optimizer to optimize the program and debugging information without
243 necessarily having to know anything about debugging information. In
244 particular, the global constant merging pass automatically eliminates
245 duplicated debugging information (often caused by header files), the global
246 dead code elimination pass automatically deletes debugging information for a
247 function if it decides to delete the function, and the linker eliminates
248 debug information when it merges <tt>linkonce</tt> functions.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]249
250<p>To do this, most of the debugging information (descriptors for types,
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]251 variables, functions, source files, etc) is inserted by the language
252 front-end in the form of LLVM global variables. These LLVM global variables
253 are no different from any other global variables, except that they have a web
254 of LLVM intrinsic functions that point to them. If the last references to a
255 particular piece of debugging information are deleted (for example, by the
256 <tt>-globaldce</tt> pass), the extraneous debug information will
257 automatically become dead and be removed by the optimizer.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]258
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]259<p>Debug information is designed to be agnostic about the target debugger and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]260 debugging information representation (e.g. DWARF/Stabs/etc). It uses a
261 generic machine debug information pass to decode the information that
262 represents variables, types, functions, namespaces, etc: this allows for
263 arbitrary source-language semantics and type-systems to be used, as long as
264 there is a module written for the target debugger to interpret the
265 information. In addition, debug global variables are declared in
266 the <tt>"llvm.metadata"</tt> section. All values declared in this section
267 are stripped away after target debug information is constructed and before
268 the program object is emitted.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]269
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]270<p>To provide basic functionality, the LLVM debugger does have to make some
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]271 assumptions about the source-level language being debugged, though it keeps
272 these to a minimum. The only common features that the LLVM debugger assumes
273 exist are <a href="#format_compile_units">source files</a>,
274 and <a href="#format_global_variables">program objects</a>. These abstract
275 objects are used by a debugger to form stack traces, show information about
276 local variables, etc.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]277
278<p>This section of the documentation first describes the representation aspects
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]279 common to any source-language. The <a href="#ccxx_frontend">next section</a>
280 describes the data layout conventions used by the C and C++ front-ends.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]281
282</div>
283
284<!-- ======================================================================= -->
285<div class="doc_subsection">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]286 <a name="debug_info_descriptors">Debug information descriptors</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]287</div>
288
289<div class="doc_text">
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]290
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]291<p>In consideration of the complexity and volume of debug information, LLVM
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]292 provides a specification for well formed debug global variables. The
293 constant value of each of these globals is one of a limited set of
294 structures, known as debug descriptors.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]295
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]296<p>Consumers of LLVM debug information expect the descriptors for program
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]297 objects to start in a canonical format, but the descriptors can include
298 additional information appended at the end that is source-language
299 specific. All LLVM debugging information is versioned, allowing backwards
300 compatibility in the case that the core structures need to change in some
301 way. Also, all debugging information objects start with a tag to indicate
302 what type of object it is. The source-language is allowed to define its own
303 objects, by using unreserved tag numbers. We recommend using with tags in
304 the range 0x1000 thru 0x2000 (there is a defined enum DW_TAG_user_base =
305 0x1000.)</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]306
Jim Laskey44c3b9f2007-01-26 21:22:28 +0000[diff] [blame]307<p>The fields of debug descriptors used internally by LLVM (MachineModuleInfo)
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]308 are restricted to only the simple data types <tt>int</tt>, <tt>uint</tt>,
309 <tt>bool</tt>, <tt>float</tt>, <tt>double</tt>, <tt>i8*</tt> and
310 <tt>{&nbsp;}*</tt>. References to arbitrary values are handled using a
311 <tt>{&nbsp;}*</tt> and a cast to <tt>{&nbsp;}*</tt> expression; typically
312 references to other field descriptors, arrays of descriptors or global
313 variables.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]314
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]315<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]316<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]317%llvm.dbg.object.type = type {
318 uint, ;; A tag
319 ...
320}
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]321</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]322</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]323
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]324<p><a name="LLVMDebugVersion">The first field of a descriptor is always an
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]325 <tt>uint</tt> containing a tag value identifying the content of the
326 descriptor. The remaining fields are specific to the descriptor. The values
327 of tags are loosely bound to the tag values of DWARF information entries.
328 However, that does not restrict the use of the information supplied to DWARF
329 targets. To facilitate versioning of debug information, the tag is augmented
330 with the current debug version (LLVMDebugVersion = 4 << 16 or 0x40000 or
331 262144.)</a></p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]332
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]333<p>The details of the various descriptors follow.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]334
335</div>
336
337<!-- ======================================================================= -->
338<div class="doc_subsubsection">
339 <a name="format_anchors">Anchor descriptors</a>
340</div>
341
342<div class="doc_text">
343
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]344<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]345<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]346%<a href="#format_anchors">llvm.dbg.anchor.type</a> = type {
347 i32, ;; Tag = 0 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
348 i32 ;; Tag of descriptors grouped by the anchor
349}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]350</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]351</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]352
353<p>One important aspect of the LLVM debug representation is that it allows the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]354 LLVM debugger to efficiently index all of the global objects without having
355 the scan the program. To do this, all of the global objects use "anchor"
356 descriptors with designated names. All of the global objects of a particular
357 type (e.g., compile units) contain a pointer to the anchor. This pointer
358 allows a debugger to use def-use chains to find all global objects of that
359 type.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]360
361<p>The following names are recognized as anchors by LLVM:</p>
362
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]363<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]364<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]365%<a href="#format_compile_units">llvm.dbg.compile_units</a> = linkonce constant %<a href="#format_anchors">llvm.dbg.anchor.type</a> {
366 i32 0,
367 i32 17
368} ;; DW_TAG_compile_unit
369%<a href="#format_global_variables">llvm.dbg.global_variables</a> = linkonce constant %<a href="#format_anchors">llvm.dbg.anchor.type</a> {
370 i32 0,
371 i32 52
372} ;; DW_TAG_variable
373%<a href="#format_subprograms">llvm.dbg.subprograms</a> = linkonce constant %<a href="#format_anchors">llvm.dbg.anchor.type</a> {
374 i32 0,
375 i32 46
376} ;; DW_TAG_subprogram
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]377</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]378</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]379
380<p>Using anchors in this way (where the compile unit descriptor points to the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]381 anchors, as opposed to having a list of compile unit descriptors) allows for
382 the standard dead global elimination and merging passes to automatically
383 remove unused debugging information. If the globals were kept track of
384 through lists, there would always be an object pointing to the descriptors,
385 thus would never be deleted.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]386
387</div>
388
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]389<!-- ======================================================================= -->
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]390<div class="doc_subsubsection">
391 <a name="format_compile_units">Compile unit descriptors</a>
392</div>
393
394<div class="doc_text">
395
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]396<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]397<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]398%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = type {
399 i32, ;; Tag = 17 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_compile_unit)
400 { }*, ;; Compile unit anchor = cast = (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_units</a> to { }*)
401 i32, ;; DWARF language identifier (ex. DW_LANG_C89)
402 i8*, ;; Source file name
403 i8*, ;; Source file directory (includes trailing slash)
404 i8* ;; Producer (ex. "4.0.1 LLVM (LLVM research group)")
405 i1, ;; True if this is a main compile unit.
406 i1, ;; True if this is optimized.
407 i8*, ;; Flags
408 i32 ;; Runtime version
409}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]410</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]411</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]412
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]413<p>These descriptors contain a source language ID for the file (we use the DWARF
414 3.0 ID numbers, such as <tt>DW_LANG_C89</tt>, <tt>DW_LANG_C_plus_plus</tt>,
415 <tt>DW_LANG_Cobol74</tt>, etc), three strings describing the filename,
416 working directory of the compiler, and an identifier string for the compiler
417 that produced it.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]418
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]419<p>Compile unit descriptors provide the root context for objects declared in a
420 specific source file. Global variables and top level functions would be
421 defined using this context. Compile unit descriptors also provide context
422 for source line correspondence.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]423
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]424<p>Each input file is encoded as a separate compile unit in LLVM debugging
425 information output. However, many target specific tool chains prefer to
426 encode only one compile unit in an object file. In this situation, the LLVM
427 code generator will include debugging information entities in the compile
428 unit that is marked as main compile unit. The code generator accepts maximum
429 one main compile unit per module. If a module does not contain any main
430 compile unit then the code generator will emit multiple compile units in the
431 output object file.</p>
432
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]433</div>
434
435<!-- ======================================================================= -->
436<div class="doc_subsubsection">
437 <a name="format_global_variables">Global variable descriptors</a>
438</div>
439
440<div class="doc_text">
441
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]442<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]443<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]444%<a href="#format_global_variables">llvm.dbg.global_variable.type</a> = type {
445 i32, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_variable)
446 { }*, ;; Global variable anchor = cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_global_variables">llvm.dbg.global_variables</a> to { }*),
447 { }*, ;; Reference to context descriptor
448 i8*, ;; Name
449 i8*, ;; Display name (fully qualified C++ name)
450 i8*, ;; MIPS linkage name (for C++)
451 { }*, ;; Reference to compile unit where defined
452 i32, ;; Line number where defined
453 { }*, ;; Reference to type descriptor
454 i1, ;; True if the global is local to compile unit (static)
455 i1, ;; True if the global is defined in the compile unit (not extern)
456 { }* ;; Reference to the global variable
457}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]458</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]459</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]460
461<p>These descriptors provide debug information about globals variables. The
462provide details such as name, type and where the variable is defined.</p>
463
464</div>
465
466<!-- ======================================================================= -->
467<div class="doc_subsubsection">
468 <a name="format_subprograms">Subprogram descriptors</a>
469</div>
470
471<div class="doc_text">
472
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]473<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]474<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]475%<a href="#format_subprograms">llvm.dbg.subprogram.type</a> = type {
476 i32, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subprogram)
477 { }*, ;; Subprogram anchor = cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_subprograms">llvm.dbg.subprograms</a> to { }*),
478 { }*, ;; Reference to context descriptor
479 i8*, ;; Name
480 i8*, ;; Display name (fully qualified C++ name)
481 i8*, ;; MIPS linkage name (for C++)
482 { }*, ;; Reference to compile unit where defined
483 i32, ;; Line number where defined
484 { }*, ;; Reference to type descriptor
485 i1, ;; True if the global is local to compile unit (static)
486 i1 ;; True if the global is defined in the compile unit (not extern)
487}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]488</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]489</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]490
491<p>These descriptors provide debug information about functions, methods and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]492 subprograms. They provide details such as name, return types and the source
493 location where the subprogram is defined.</p>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]494
495</div>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]496
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]497<!-- ======================================================================= -->
498<div class="doc_subsubsection">
499 <a name="format_blocks">Block descriptors</a>
500</div>
501
502<div class="doc_text">
503
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]504<div class="doc_code">
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]505<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]506%<a href="#format_blocks">llvm.dbg.block</a> = type {
507 i32, ;; Tag = 13 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
508 { }* ;; Reference to context descriptor
509}
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]510</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]511</div>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]512
513<p>These descriptors provide debug information about nested blocks within a
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]514 subprogram. The array of member descriptors is used to define local
515 variables and deeper nested blocks.</p>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]516
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]517</div>
518
519<!-- ======================================================================= -->
520<div class="doc_subsubsection">
521 <a name="format_basic_type">Basic type descriptors</a>
522</div>
523
524<div class="doc_text">
525
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]526<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]527<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]528%<a href="#format_basic_type">llvm.dbg.basictype.type</a> = type {
529 i32, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_base_type)
530 { }*, ;; Reference to context (typically a compile unit)
531 i8*, ;; Name (may be "" for anonymous types)
532 { }*, ;; Reference to compile unit where defined (may be NULL)
533 i32, ;; Line number where defined (may be 0)
534 i64, ;; Size in bits
535 i64, ;; Alignment in bits
536 i64, ;; Offset in bits
537 i32, ;; Flags
538 i32 ;; DWARF type encoding
539}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]540</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]541</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]542
543<p>These descriptors define primitive types used in the code. Example int, bool
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]544 and float. The context provides the scope of the type, which is usually the
545 top level. Since basic types are not usually user defined the compile unit
546 and line number can be left as NULL and 0. The size, alignment and offset
547 are expressed in bits and can be 64 bit values. The alignment is used to
548 round the offset when embedded in a
549 <a href="#format_composite_type">composite type</a> (example to keep float
550 doubles on 64 bit boundaries.) The offset is the bit offset if embedded in
551 a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]552
553<p>The type encoding provides the details of the type. The values are typically
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]554 one of the following:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]555
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]556<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]557<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]558DW_ATE_address = 1
559DW_ATE_boolean = 2
560DW_ATE_float = 4
561DW_ATE_signed = 5
562DW_ATE_signed_char = 6
563DW_ATE_unsigned = 7
564DW_ATE_unsigned_char = 8
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]565</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]566</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]567
568</div>
569
570<!-- ======================================================================= -->
571<div class="doc_subsubsection">
572 <a name="format_derived_type">Derived type descriptors</a>
573</div>
574
575<div class="doc_text">
576
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]577<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]578<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]579%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> = type {
580 i32, ;; Tag (see below)
581 { }*, ;; Reference to context
582 i8*, ;; Name (may be "" for anonymous types)
583 { }*, ;; Reference to compile unit where defined (may be NULL)
584 i32, ;; Line number where defined (may be 0)
585 i32, ;; Size in bits
586 i32, ;; Alignment in bits
587 i32, ;; Offset in bits
588 { }* ;; Reference to type derived from
589}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]590</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]591</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]592
593<p>These descriptors are used to define types derived from other types. The
594value of the tag varies depending on the meaning. The following are possible
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]595tag values:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]596
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]597<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]598<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]599DW_TAG_formal_parameter = 5
600DW_TAG_member = 13
601DW_TAG_pointer_type = 15
602DW_TAG_reference_type = 16
603DW_TAG_typedef = 22
604DW_TAG_const_type = 38
605DW_TAG_volatile_type = 53
606DW_TAG_restrict_type = 55
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]607</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]608</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]609
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]610<p><tt>DW_TAG_member</tt> is used to define a member of
611 a <a href="#format_composite_type">composite type</a>
612 or <a href="#format_subprograms">subprogram</a>. The type of the member is
613 the <a href="#format_derived_type">derived
614 type</a>. <tt>DW_TAG_formal_parameter</tt> is used to define a member which
615 is a formal argument of a subprogram.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]616
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]617<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]618
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]619<p><tt>DW_TAG_pointer_type</tt>,<tt>DW_TAG_reference_type</tt>,
620 <tt>DW_TAG_const_type</tt>, <tt>DW_TAG_volatile_type</tt>
621 and <tt>DW_TAG_restrict_type</tt> are used to qualify
622 the <a href="#format_derived_type">derived type</a>. </p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]623
624<p><a href="#format_derived_type">Derived type</a> location can be determined
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]625 from the compile unit and line number. The size, alignment and offset are
626 expressed in bits and can be 64 bit values. The alignment is used to round
627 the offset when embedded in a <a href="#format_composite_type">composite
628 type</a> (example to keep float doubles on 64 bit boundaries.) The offset is
629 the bit offset if embedded in a <a href="#format_composite_type">composite
630 type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]631
632<p>Note that the <tt>void *</tt> type is expressed as a
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]633 <tt>llvm.dbg.derivedtype.type</tt> with tag of <tt>DW_TAG_pointer_type</tt>
634 and <tt>NULL</tt> derived type.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]635
636</div>
637
638<!-- ======================================================================= -->
639<div class="doc_subsubsection">
640 <a name="format_composite_type">Composite type descriptors</a>
641</div>
642
643<div class="doc_text">
644
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]645<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]646<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]647%<a href="#format_composite_type">llvm.dbg.compositetype.type</a> = type {
648 i32, ;; Tag (see below)
649 { }*, ;; Reference to context
650 i8*, ;; Name (may be "" for anonymous types)
651 { }*, ;; Reference to compile unit where defined (may be NULL)
652 i32, ;; Line number where defined (may be 0)
653 i64, ;; Size in bits
654 i64, ;; Alignment in bits
655 i64, ;; Offset in bits
656 i32, ;; Flags
657 { }*, ;; Reference to type derived from
658 { }*, ;; Reference to array of member descriptors
659 i32 ;; Runtime languages
660}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]661</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]662</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]663
664<p>These descriptors are used to define types that are composed of 0 or more
665elements. The value of the tag varies depending on the meaning. The following
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]666are possible tag values:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]667
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]668<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]669<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]670DW_TAG_array_type = 1
671DW_TAG_enumeration_type = 4
672DW_TAG_structure_type = 19
673DW_TAG_union_type = 23
674DW_TAG_vector_type = 259
675DW_TAG_subroutine_type = 46
676DW_TAG_inheritance = 26
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]677</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]678</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]679
Jim Laskeyf8a01a92006-06-15 20:51:43 +0000[diff] [blame]680<p>The vector flag indicates that an array type is a native packed vector.</p>
681
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]682<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^]683 (tag = <tt>DW_TAG_vector_type</tt>) are <a href="#format_subrange">subrange
684 descriptors</a>, each representing the range of subscripts at that level of
685 indexing.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]686
687<p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]688 <a href="#format_enumeration">enumerator descriptors</a>, each representing
689 the definition of enumeration value for the set.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]690
691<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^]692 = <tt>DW_TAG_union_type</tt>) types are any one of
693 the <a href="#format_basic_type">basic</a>,
694 <a href="#format_derived_type">derived</a>
695 or <a href="#format_composite_type">composite</a> type descriptors, each
696 representing a field member of the structure or union.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]697
Jim Laskey4a9df242006-08-21 21:21:06 +0000[diff] [blame]698<p>For C++ classes (tag = <tt>DW_TAG_structure_type</tt>), member descriptors
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]699 provide information about base classes, static members and member
700 functions. If a member is a <a href="#format_derived_type">derived type
701 descriptor</a> and has a tag of <tt>DW_TAG_inheritance</tt>, then the type
702 represents a base class. If the member of is
703 a <a href="#format_global_variables">global variable descriptor</a> then it
704 represents a static member. And, if the member is
705 a <a href="#format_subprograms">subprogram descriptor</a> then it represents
706 a member function. For static members and member
707 functions, <tt>getName()</tt> returns the members link or the C++ mangled
708 name. <tt>getDisplayName()</tt> the simplied version of the name.</p>
Jim Laskey4a9df242006-08-21 21:21:06 +0000[diff] [blame]709
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]710<p>The first member of subroutine (tag = <tt>DW_TAG_subroutine_type</tt>) type
711 elements is the return type for the subroutine. The remaining elements are
712 the formal arguments to the subroutine.</p>
Jim Laskey094ee722006-06-20 21:13:20 +0000[diff] [blame]713
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]714<p><a href="#format_composite_type">Composite type</a> location can be
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]715 determined from the compile unit and line number. The size, alignment and
716 offset are expressed in bits and can be 64 bit values. The alignment is used
717 to round the offset when embedded in
718 a <a href="#format_composite_type">composite type</a> (as an example, to keep
719 float doubles on 64 bit boundaries.) The offset is the bit offset if embedded
720 in a <a href="#format_composite_type">composite type</a>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]721
722</div>
723
724<!-- ======================================================================= -->
725<div class="doc_subsubsection">
726 <a name="format_subrange">Subrange descriptors</a>
727</div>
728
729<div class="doc_text">
730
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]731<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]732<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]733%<a href="#format_subrange">llvm.dbg.subrange.type</a> = type {
734 i32, ;; Tag = 33 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subrange_type)
735 i64, ;; Low value
736 i64 ;; High value
737}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]738</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]739</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]740
741<p>These descriptors are used to define ranges of array subscripts for an array
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]742 <a href="#format_composite_type">composite type</a>. The low value defines
743 the lower bounds typically zero for C/C++. The high value is the upper
744 bounds. Values are 64 bit. High - low + 1 is the size of the array. If low
745 == high the array will be unbounded.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]746
747</div>
748
749<!-- ======================================================================= -->
750<div class="doc_subsubsection">
751 <a name="format_enumeration">Enumerator descriptors</a>
752</div>
753
754<div class="doc_text">
755
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]756<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]757<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]758%<a href="#format_enumeration">llvm.dbg.enumerator.type</a> = type {
759 i32, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_enumerator)
760 i8*, ;; Name
761 i64 ;; Value
762}
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]763</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]764</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]765
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]766<p>These descriptors are used to define members of an
767 enumeration <a href="#format_composite_type">composite type</a>, it
768 associates the name to the value.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]769
770</div>
771
772<!-- ======================================================================= -->
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]773<div class="doc_subsubsection">
774 <a name="format_variables">Local variables</a>
775</div>
776
777<div class="doc_text">
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]778
779<div class="doc_code">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]780<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]781%<a href="#format_variables">llvm.dbg.variable.type</a> = type {
782 i32, ;; Tag (see below)
783 { }*, ;; Context
784 i8*, ;; Name
785 { }*, ;; Reference to compile unit where defined
786 i32, ;; Line number where defined
787 { }* ;; Type descriptor
788}
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]789</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]790</div>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]791
792<p>These descriptors are used to define variables local to a sub program. The
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]793 value of the tag depends on the usage of the variable:</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]794
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]795<div class="doc_code">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]796<pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]797DW_TAG_auto_variable = 256
798DW_TAG_arg_variable = 257
799DW_TAG_return_variable = 258
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]800</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]801</div>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]802
803<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^]804 argument variable is any variable that appears as a formal argument to the
805 function. A return variable is used to track the result of a function and
806 has no source correspondent.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]807
Jim Laskey2d395d92006-03-24 09:20:27 +0000[diff] [blame]808<p>The context is either the subprogram or block where the variable is defined.
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]809 Name the source variable name. Compile unit and line indicate where the
810 variable was defined. Type descriptor defines the declared type of the
811 variable.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]812
813</div>
814
815<!-- ======================================================================= -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]816<div class="doc_subsection">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]817 <a name="format_common_intrinsics">Debugger intrinsic functions</a>
818</div>
819
820<div class="doc_text">
821
822<p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]823 provide debug information at various points in generated code.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]824
825</div>
826
827<!-- ======================================================================= -->
828<div class="doc_subsubsection">
829 <a name="format_common_stoppoint">llvm.dbg.stoppoint</a>
830</div>
831
832<div class="doc_text">
833<pre>
Jim Laskey108a6382006-03-23 17:58:46 +0000[diff] [blame]834 void %<a href="#format_common_stoppoint">llvm.dbg.stoppoint</a>( uint, uint, { }* )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]835</pre>
836
837<p>This intrinsic is used to provide correspondence between the source file and
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]838 the generated code. The first argument is the line number (base 1), second
839 argument is the column number (0 if unknown) and the third argument the
840 source <tt>%<a href="#format_compile_units">llvm.dbg.compile_unit</a>*</tt>
841 cast to a <tt>{&nbsp;}*</tt>. Code following a call to this intrinsic will
842 have been defined in close proximity of the line, column and file. This
843 information holds until the next call
844 to <tt>%<a href="#format_common_stoppoint">lvm.dbg.stoppoint</a></tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]845
846</div>
847
848<!-- ======================================================================= -->
849<div class="doc_subsubsection">
850 <a name="format_common_func_start">llvm.dbg.func.start</a>
851</div>
852
853<div class="doc_text">
854<pre>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]855 void %<a href="#format_common_func_start">llvm.dbg.func.start</a>( { }* )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]856</pre>
857
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]858<p>This intrinsic is used to link the debug information
859 in <tt>%<a href="#format_subprograms">llvm.dbg.subprogram</a></tt> to the
860 function. It defines the beginning of the function's declarative region
861 (scope). It also implies a call to
862 %<tt><a href="#format_common_stoppoint">llvm.dbg.stoppoint</a></tt> which
863 defines a source line "stop point". The intrinsic should be called early in
864 the function after the all the alloca instructions. It should be paired off
865 with a closing
866 <tt>%<a href="#format_common_region_end">llvm.dbg.region.end</a></tt>.
867 The function's single argument is
868 the <tt>%<a href="#format_subprograms">llvm.dbg.subprogram.type</a></tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]869
870</div>
871
872<!-- ======================================================================= -->
873<div class="doc_subsubsection">
874 <a name="format_common_region_start">llvm.dbg.region.start</a>
875</div>
876
877<div class="doc_text">
878<pre>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]879 void %<a href="#format_common_region_start">llvm.dbg.region.start</a>( { }* )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]880</pre>
881
882<p>This intrinsic is used to define the beginning of a declarative scope (ex.
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]883 block) for local language elements. It should be paired off with a closing
884 <tt>%<a href="#format_common_region_end">llvm.dbg.region.end</a></tt>. The
885 function's single argument is
886 the <tt>%<a href="#format_blocks">llvm.dbg.block</a></tt> which is
887 starting.</p>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]888
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]889
890</div>
891
892<!-- ======================================================================= -->
893<div class="doc_subsubsection">
894 <a name="format_common_region_end">llvm.dbg.region.end</a>
895</div>
896
897<div class="doc_text">
898<pre>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]899 void %<a href="#format_common_region_end">llvm.dbg.region.end</a>( { }* )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]900</pre>
901
902<p>This intrinsic is used to define the end of a declarative scope (ex. block)
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]903 for local language elements. It should be paired off with an
904 opening <tt>%<a href="#format_common_region_start">llvm.dbg.region.start</a></tt>
905 or <tt>%<a href="#format_common_func_start">llvm.dbg.func.start</a></tt>.
906 The function's single argument is either
907 the <tt>%<a href="#format_blocks">llvm.dbg.block</a></tt> or
908 the <tt>%<a href="#format_subprograms">llvm.dbg.subprogram.type</a></tt>
909 which is ending.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]910
911</div>
912
913<!-- ======================================================================= -->
914<div class="doc_subsubsection">
915 <a name="format_common_declare">llvm.dbg.declare</a>
916</div>
917
918<div class="doc_text">
919<pre>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]920 void %<a href="#format_common_declare">llvm.dbg.declare</a>( { } *, { }* )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]921</pre>
922
Jim Laskey2d395d92006-03-24 09:20:27 +0000[diff] [blame]923<p>This intrinsic provides information about a local element (ex. variable.) The
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]924 first argument is the alloca for the variable, cast to a <tt>{ }*</tt>. The
925 second argument is
926 the <tt>%<a href="#format_variables">llvm.dbg.variable</a></tt> containing
927 the description of the variable, also cast to a <tt>{ }*</tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]928
929</div>
930
931<!-- ======================================================================= -->
932<div class="doc_subsection">
933 <a name="format_common_stoppoints">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]934 Representing stopping points in the source program
935 </a>
936</div>
937
938<div class="doc_text">
939
940<p>LLVM debugger "stop points" are a key part of the debugging representation
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]941 that allows the LLVM to maintain simple semantics
942 for <a href="#debugopt">debugging optimized code</a>. The basic idea is that
943 the front-end inserts calls to
944 the <a href="#format_common_stoppoint">%<tt>llvm.dbg.stoppoint</tt></a>
945 intrinsic function at every point in the program where a debugger should be
946 able to inspect the program (these correspond to places a debugger stops when
947 you "<tt>step</tt>" through it). The front-end can choose to place these as
948 fine-grained as it would like (for example, before every subexpression
949 evaluated), but it is recommended to only put them after every source
950 statement that includes executable code.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]951
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]952<p>Using calls to this intrinsic function to demark legal points for the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]953 debugger to inspect the program automatically disables any optimizations that
954 could potentially confuse debugging information. To
955 non-debug-information-aware transformations, these calls simply look like
956 calls to an external function, which they must assume to do anything
957 (including reading or writing to any part of reachable memory). On the other
958 hand, it does not impact many optimizations, such as code motion of
959 non-trapping instructions, nor does it impact optimization of subexpressions,
960 code duplication transformations, or basic-block reordering
961 transformations.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]962
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]963</div>
964
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]965<!-- ======================================================================= -->
966<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]967 <a name="format_common_lifetime">Object lifetimes and scoping</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]968</div>
969
970<div class="doc_text">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]971<p>In many languages, the local variables in functions can have their lifetime
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]972 or scope limited to a subset of a function. In the C family of languages,
973 for example, variables are only live (readable and writable) within the
974 source block that they are defined in. In functional languages, values are
975 only readable after they have been defined. Though this is a very obvious
976 concept, it is also non-trivial to model in LLVM, because it has no notion of
977 scoping in this sense, and does not want to be tied to a language's scoping
978 rules.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]979
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]980<p>In order to handle this, the LLVM debug format uses the notion of "regions"
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]981 of a function, delineated by calls to intrinsic functions. These intrinsic
982 functions define new regions of the program and indicate when the region
983 lifetime expires. Consider the following C fragment, for example:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]984
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]985<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]986<pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]9871. void foo() {
9882. int X = ...;
9893. int Y = ...;
9904. {
9915. int Z = ...;
9926. ...
9937. }
9948. ...
9959. }
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]996</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]997</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]998
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]999<p>Compiled to LLVM, this function would be represented like this:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1000
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1001<div class="doc_code">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1002<pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1003void %foo() {
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1004entry:
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1005 %X = alloca int
1006 %Y = alloca int
1007 %Z = alloca int
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1008
1009 ...
1010
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1011 call void @<a href="#format_common_func_start">llvm.dbg.func.start</a>( %<a href="#format_subprograms">llvm.dbg.subprogram.type</a>* @llvm.dbg.subprogram )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1012
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1013 call void @<a href="#format_common_stoppoint">llvm.dbg.stoppoint</a>( uint 2, uint 2, %<a href="#format_compile_units">llvm.dbg.compile_unit</a>* @llvm.dbg.compile_unit )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1014
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1015 call void @<a href="#format_common_declare">llvm.dbg.declare</a>({}* %X, ...)
1016 call void @<a href="#format_common_declare">llvm.dbg.declare</a>({}* %Y, ...)
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1017
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1018 <i>;; Evaluate expression on line 2, assigning to X.</i>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1019
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1020 call void @<a href="#format_common_stoppoint">llvm.dbg.stoppoint</a>( uint 3, uint 2, %<a href="#format_compile_units">llvm.dbg.compile_unit</a>* @llvm.dbg.compile_unit )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1021
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1022 <i>;; Evaluate expression on line 3, assigning to Y.</i>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1023
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1024 call void @<a href="#format_common_stoppoint">llvm.region.start</a>()
1025 call void @<a href="#format_common_stoppoint">llvm.dbg.stoppoint</a>( uint 5, uint 4, %<a href="#format_compile_units">llvm.dbg.compile_unit</a>* @llvm.dbg.compile_unit )
1026 call void @<a href="#format_common_declare">llvm.dbg.declare</a>({}* %X, ...)
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1027
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1028 <i>;; Evaluate expression on line 5, assigning to Z.</i>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1029
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1030 call void @<a href="#format_common_stoppoint">llvm.dbg.stoppoint</a>( uint 7, uint 2, %<a href="#format_compile_units">llvm.dbg.compile_unit</a>* @llvm.dbg.compile_unit )
1031 call void @<a href="#format_common_region_end">llvm.region.end</a>()
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1032
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1033 call void @<a href="#format_common_stoppoint">llvm.dbg.stoppoint</a>( uint 9, uint 2, %<a href="#format_compile_units">llvm.dbg.compile_unit</a>* @llvm.dbg.compile_unit )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1034
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1035 call void @<a href="#format_common_region_end">llvm.region.end</a>()
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1036
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1037 ret void
1038}
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1039</pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1040</div>
1041
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1042<p>This example illustrates a few important details about the LLVM debugging
1043 information. In particular, it shows how the various intrinsics are applied
1044 together to allow a debugger to analyze the relationship between statements,
1045 variable definitions, and the code used to implement the function.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1046
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1047<p>The first
1048 intrinsic <tt>%<a href="#format_common_func_start">llvm.dbg.func.start</a></tt>
1049 provides a link with the <a href="#format_subprograms">subprogram
1050 descriptor</a> containing the details of this function. This call also
1051 defines the beginning of the function region, bounded by
1052 the <tt>%<a href="#format_common_region_end">llvm.region.end</a></tt> at the
1053 end of the function. This region is used to bracket the lifetime of
1054 variables declared within. For a function, this outer region defines a new
1055 stack frame whose lifetime ends when the region is ended.</p>
1056
1057<p>It is possible to define inner regions for short term variables by using the
1058 %<a href="#format_common_stoppoint"><tt>llvm.region.start</tt></a>
1059 and <a href="#format_common_region_end"><tt>%llvm.region.end</tt></a> to
1060 bound a region. The inner region in this example would be for the block
1061 containing the declaration of Z.</p>
1062
1063<p>Using regions to represent the boundaries of source-level functions allow
1064 LLVM interprocedural optimizations to arbitrarily modify LLVM functions
1065 without having to worry about breaking mapping information between the LLVM
1066 code and the and source-level program. In particular, the inliner requires
1067 no modification to support inlining with debugging information: there is no
1068 explicit correlation drawn between LLVM functions and their source-level
1069 counterparts (note however, that if the inliner inlines all instances of a
1070 non-strong-linkage function into its caller that it will not be possible for
1071 the user to manually invoke the inlined function from a debugger).</p>
1072
1073<p>Once the function has been defined,
1074 the <a href="#format_common_stoppoint"><tt>stopping point</tt></a>
1075 corresponding to line #2 (column #2) of the function is encountered. At this
1076 point in the function, <b>no</b> local variables are live. As lines 2 and 3
1077 of the example are executed, their variable definitions are introduced into
1078 the program using
1079 %<a href="#format_common_declare"><tt>llvm.dbg.declare</tt></a>, without the
1080 need to specify a new region. These variables do not require new regions to
1081 be introduced because they go out of scope at the same point in the program:
1082 line 9.</p>
1083
1084<p>In contrast, the <tt>Z</tt> variable goes out of scope at a different time,
1085 on line 7. For this reason, it is defined within the inner region, which
1086 kills the availability of <tt>Z</tt> before the code for line 8 is executed.
1087 In this way, regions can support arbitrary source-language scoping rules, as
1088 long as they can only be nested (ie, one scope cannot partially overlap with
1089 a part of another scope).</p>
1090
1091<p>It is worth noting that this scoping mechanism is used to control scoping of
1092 all declarations, not just variable declarations. For example, the scope of
1093 a C++ using declaration is controlled with this and could change how name
1094 lookup is performed.</p>
1095
1096</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1097
1098<!-- *********************************************************************** -->
1099<div class="doc_section">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1100 <a name="ccxx_frontend">C/C++ front-end specific debug information</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1101</div>
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]1102<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1103
1104<div class="doc_text">
1105
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1106<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^]1107 that is effectively identical
1108 to <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3.0</a> in
1109 terms of information content. This allows code generators to trivially
1110 support native debuggers by generating standard dwarf information, and
1111 contains enough information for non-dwarf targets to translate it as
1112 needed.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1113
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1114<p>This section describes the forms used to represent C and C++ programs. Other
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1115 languages could pattern themselves after this (which itself is tuned to
1116 representing programs in the same way that DWARF 3 does), or they could
1117 choose to provide completely different forms if they don't fit into the DWARF
1118 model. As support for debugging information gets added to the various LLVM
1119 source-language front-ends, the information used should be documented
1120 here.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1121
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1122<p>The following sections provide examples of various C/C++ constructs and the
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1123 debug information that would best describe those constructs.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1124
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1125</div>
1126
1127<!-- ======================================================================= -->
1128<div class="doc_subsection">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1129 <a name="ccxx_compile_units">C/C++ source file information</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1130</div>
1131
1132<div class="doc_text">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1133
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1134<p>Given the source files <tt>MySource.cpp</tt> and <tt>MyHeader.h</tt> located
1135 in the directory <tt>/Users/mine/sources</tt>, the following code:</p>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1136
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1137<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1138<pre>
1139#include "MyHeader.h"
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1140
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1141int main(int argc, char *argv[]) {
1142 return 0;
1143}
1144</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1145</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1146
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1147<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1148
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1149<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1150<pre>
1151...
1152;;
1153;; Define types used. In this case we need one for compile unit anchors and one
1154;; for compile units.
1155;;
1156%<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint }
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1157%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = type { uint, { }*, uint, uint, i8*, i8*, i8* }
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1158...
1159;;
1160;; Define the anchor for compile units. Note that the second field of the
1161;; anchor is 17, which is the same as the tag for compile units
1162;; (17 = DW_TAG_compile_unit.)
1163;;
1164%<a href="#format_compile_units">llvm.dbg.compile_units</a> = linkonce constant %<a href="#format_anchors">llvm.dbg.anchor.type</a> { uint 0, uint 17 }, section "llvm.metadata"
1165
1166;;
1167;; Define the compile unit for the source file "/Users/mine/sources/MySource.cpp".
1168;;
1169%<a href="#format_compile_units">llvm.dbg.compile_unit1</a> = internal constant %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1170 uint add(uint 17, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1171 { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_units</a> to { }*),
1172 uint 1,
1173 uint 1,
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1174 i8* getelementptr ([13 x i8]* %str1, i32 0, i32 0),
1175 i8* getelementptr ([21 x i8]* %str2, i32 0, i32 0),
1176 i8* getelementptr ([33 x i8]* %str3, i32 0, i32 0) }, section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1177
1178;;
1179;; Define the compile unit for the header file "/Users/mine/sources/MyHeader.h".
1180;;
1181%<a href="#format_compile_units">llvm.dbg.compile_unit2</a> = internal constant %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1182 uint add(uint 17, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1183 { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_units</a> to { }*),
1184 uint 1,
1185 uint 1,
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1186 i8* getelementptr ([11 x i8]* %str4, int 0, int 0),
1187 i8* getelementptr ([21 x i8]* %str2, int 0, int 0),
1188 i8* getelementptr ([33 x i8]* %str3, int 0, int 0) }, section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1189
1190;;
1191;; Define each of the strings used in the compile units.
1192;;
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1193%str1 = internal constant [13 x i8] c"MySource.cpp\00", section "llvm.metadata";
1194%str2 = internal constant [21 x i8] c"/Users/mine/sources/\00", section "llvm.metadata";
1195%str3 = internal constant [33 x i8] c"4.0.1 LLVM (LLVM research group)\00", section "llvm.metadata";
1196%str4 = internal constant [11 x i8] c"MyHeader.h\00", section "llvm.metadata";
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1197...
1198</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1199</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1200
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1201</div>
1202
1203<!-- ======================================================================= -->
1204<div class="doc_subsection">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1205 <a name="ccxx_global_variable">C/C++ global variable information</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1206</div>
1207
1208<div class="doc_text">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1209
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1210<p>Given an integer global variable declared as follows:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1211
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1212<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1213<pre>
1214int MyGlobal = 100;
1215</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1216</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1217
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1218<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1219
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1220<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1221<pre>
1222;;
1223;; Define types used. One for global variable anchors, one for the global
1224;; variable descriptor, one for the global's basic type and one for the global's
1225;; compile unit.
1226;;
1227%<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint }
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1228%<a href="#format_global_variables">llvm.dbg.global_variable.type</a> = type { uint, { }*, { }*, i8*, { }*, uint, { }*, bool, bool, { }*, uint }
1229%<a href="#format_basic_type">llvm.dbg.basictype.type</a> = type { uint, { }*, i8*, { }*, int, uint, uint, uint, uint }
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1230%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = ...
1231...
1232;;
1233;; Define the global itself.
1234;;
1235%MyGlobal = global int 100
1236...
1237;;
1238;; Define the anchor for global variables. Note that the second field of the
1239;; anchor is 52, which is the same as the tag for global variables
1240;; (52 = DW_TAG_variable.)
1241;;
1242%<a href="#format_global_variables">llvm.dbg.global_variables</a> = linkonce constant %<a href="#format_anchors">llvm.dbg.anchor.type</a> { uint 0, uint 52 }, section "llvm.metadata"
1243
1244;;
1245;; Define the global variable descriptor. Note the reference to the global
1246;; variable anchor and the global variable itself.
1247;;
1248%<a href="#format_global_variables">llvm.dbg.global_variable</a> = internal constant %<a href="#format_global_variables">llvm.dbg.global_variable.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1249 uint add(uint 52, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1250 { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_global_variables">llvm.dbg.global_variables</a> to { }*),
1251 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1252 i8* getelementptr ([9 x i8]* %str1, int 0, int 0),
1253 i8* getelementptr ([1 x i8]* %str2, int 0, int 0),
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]1254 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1255 uint 1,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1256 { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*),
1257 bool false,
1258 bool true,
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]1259 { }* cast (int* %MyGlobal to { }*) }, section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1260
1261;;
1262;; Define the basic type of 32 bit signed integer. Note that since int is an
1263;; intrinsic type the source file is NULL and line 0.
1264;;
1265%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1266 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1267 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1268 i8* getelementptr ([4 x i8]* %str3, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1269 { }* null,
1270 int 0,
1271 uint 32,
1272 uint 32,
1273 uint 0,
1274 uint 5 }, section "llvm.metadata"
1275
1276;;
1277;; Define the names of the global variable and basic type.
1278;;
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1279%str1 = internal constant [9 x i8] c"MyGlobal\00", section "llvm.metadata"
1280%str2 = internal constant [1 x i8] c"\00", section "llvm.metadata"
1281%str3 = internal constant [4 x i8] c"int\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1282</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1283</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1284
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1285</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1286
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1287<!-- ======================================================================= -->
1288<div class="doc_subsection">
1289 <a name="ccxx_subprogram">C/C++ function information</a>
1290</div>
1291
1292<div class="doc_text">
1293
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1294<p>Given a function declared as follows:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1295
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1296<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1297<pre>
1298int main(int argc, char *argv[]) {
1299 return 0;
1300}
1301</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1302</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1303
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1304<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1305
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1306<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1307<pre>
1308;;
1309;; Define types used. One for subprogram anchors, one for the subprogram
1310;; descriptor, one for the global's basic type and one for the subprogram's
1311;; compile unit.
1312;;
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1313%<a href="#format_subprograms">llvm.dbg.subprogram.type</a> = type { uint, { }*, { }*, i8*, { }*, bool, bool }
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1314%<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint }
1315%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = ...
1316
1317;;
1318;; Define the anchor for subprograms. Note that the second field of the
1319;; anchor is 46, which is the same as the tag for subprograms
1320;; (46 = DW_TAG_subprogram.)
1321;;
1322%<a href="#format_subprograms">llvm.dbg.subprograms</a> = linkonce constant %<a href="#format_anchors">llvm.dbg.anchor.type</a> { uint 0, uint 46 }, section "llvm.metadata"
1323
1324;;
1325;; Define the descriptor for the subprogram. TODO - more details.
1326;;
1327%<a href="#format_subprograms">llvm.dbg.subprogram</a> = internal constant %<a href="#format_subprograms">llvm.dbg.subprogram.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1328 uint add(uint 46, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1329 { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_subprograms">llvm.dbg.subprograms</a> to { }*),
1330 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1331 i8* getelementptr ([5 x i8]* %str1, int 0, int 0),
1332 i8* getelementptr ([1 x i8]* %str2, int 0, int 0),
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]1333 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1334 uint 1,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1335 { }* null,
1336 bool false,
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]1337 bool true }, section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1338
1339;;
1340;; Define the name of the subprogram.
1341;;
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1342%str1 = internal constant [5 x i8] c"main\00", section "llvm.metadata"
1343%str2 = internal constant [1 x i8] c"\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1344
1345;;
1346;; Define the subprogram itself.
1347;;
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1348int %main(int %argc, i8** %argv) {
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1349...
1350}
1351</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1352</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1353
1354</div>
1355
1356<!-- ======================================================================= -->
1357<div class="doc_subsection">
1358 <a name="ccxx_basic_types">C/C++ basic types</a>
1359</div>
1360
1361<div class="doc_text">
1362
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1363<p>The following are the basic type descriptors for C/C++ core types:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1364
1365</div>
1366
1367<!-- ======================================================================= -->
1368<div class="doc_subsubsection">
1369 <a name="ccxx_basic_type_bool">bool</a>
1370</div>
1371
1372<div class="doc_text">
1373
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1374<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1375<pre>
1376%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1377 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1378 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1379 i8* getelementptr ([5 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1380 { }* null,
1381 int 0,
1382 uint 32,
1383 uint 32,
1384 uint 0,
1385 uint 2 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1386%str1 = internal constant [5 x i8] c"bool\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1387</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1388</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1389
1390</div>
1391
1392<!-- ======================================================================= -->
1393<div class="doc_subsubsection">
1394 <a name="ccxx_basic_char">char</a>
1395</div>
1396
1397<div class="doc_text">
1398
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1399<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1400<pre>
1401%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1402 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1403 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1404 i8* getelementptr ([5 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1405 { }* null,
1406 int 0,
1407 uint 8,
1408 uint 8,
1409 uint 0,
1410 uint 6 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1411%str1 = internal constant [5 x i8] c"char\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1412</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1413</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1414
1415</div>
1416
1417<!-- ======================================================================= -->
1418<div class="doc_subsubsection">
1419 <a name="ccxx_basic_unsigned_char">unsigned char</a>
1420</div>
1421
1422<div class="doc_text">
1423
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1424<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1425<pre>
1426%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1427 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1428 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1429 i8* getelementptr ([14 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1430 { }* null,
1431 int 0,
1432 uint 8,
1433 uint 8,
1434 uint 0,
1435 uint 8 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1436%str1 = internal constant [14 x i8] c"unsigned char\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1437</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1438</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1439
1440</div>
1441
1442<!-- ======================================================================= -->
1443<div class="doc_subsubsection">
1444 <a name="ccxx_basic_short">short</a>
1445</div>
1446
1447<div class="doc_text">
1448
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1449<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1450<pre>
1451%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1452 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1453 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1454 i8* getelementptr ([10 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1455 { }* null,
1456 int 0,
1457 uint 16,
1458 uint 16,
1459 uint 0,
1460 uint 5 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1461%str1 = internal constant [10 x i8] c"short int\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1462</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1463</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1464
1465</div>
1466
1467<!-- ======================================================================= -->
1468<div class="doc_subsubsection">
1469 <a name="ccxx_basic_unsigned_short">unsigned short</a>
1470</div>
1471
1472<div class="doc_text">
1473
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1474<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1475<pre>
1476%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1477 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1478 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1479 i8* getelementptr ([19 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1480 { }* null,
1481 int 0,
1482 uint 16,
1483 uint 16,
1484 uint 0,
1485 uint 7 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1486%str1 = internal constant [19 x i8] c"short unsigned int\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1487</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1488</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1489
1490</div>
1491
1492<!-- ======================================================================= -->
1493<div class="doc_subsubsection">
1494 <a name="ccxx_basic_int">int</a>
1495</div>
1496
1497<div class="doc_text">
1498
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1499<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1500<pre>
1501%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1502 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1503 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1504 i8* getelementptr ([4 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1505 { }* null,
1506 int 0,
1507 uint 32,
1508 uint 32,
1509 uint 0,
1510 uint 5 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1511%str1 = internal constant [4 x i8] c"int\00", section "llvm.metadata"
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1512</pre></div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1513
1514</div>
1515
1516<!-- ======================================================================= -->
1517<div class="doc_subsubsection">
1518 <a name="ccxx_basic_unsigned_int">unsigned int</a>
1519</div>
1520
1521<div class="doc_text">
1522
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1523<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1524<pre>
1525%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1526 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1527 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1528 i8* getelementptr ([13 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1529 { }* null,
1530 int 0,
1531 uint 32,
1532 uint 32,
1533 uint 0,
1534 uint 7 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1535%str1 = internal constant [13 x i8] c"unsigned int\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1536</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1537</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1538
1539</div>
1540
1541<!-- ======================================================================= -->
1542<div class="doc_subsubsection">
1543 <a name="ccxx_basic_long_long">long long</a>
1544</div>
1545
1546<div class="doc_text">
1547
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1548<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1549<pre>
1550%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1551 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1552 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1553 i8* getelementptr ([14 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1554 { }* null,
1555 int 0,
1556 uint 64,
1557 uint 64,
1558 uint 0,
1559 uint 5 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1560%str1 = internal constant [14 x i8] c"long long int\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1561</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1562</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1563
1564</div>
1565
1566<!-- ======================================================================= -->
1567<div class="doc_subsubsection">
1568 <a name="ccxx_basic_unsigned_long_long">unsigned long long</a>
1569</div>
1570
1571<div class="doc_text">
1572
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1573<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1574<pre>
1575%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1576 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1577 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1578 i8* getelementptr ([23 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1579 { }* null,
1580 int 0,
1581 uint 64,
1582 uint 64,
1583 uint 0,
1584 uint 7 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1585%str1 = internal constant [23 x 8] c"long long unsigned int\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1586</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1587</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1588
1589</div>
1590
1591<!-- ======================================================================= -->
1592<div class="doc_subsubsection">
1593 <a name="ccxx_basic_float">float</a>
1594</div>
1595
1596<div class="doc_text">
1597
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1598<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1599<pre>
1600%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1601 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1602 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1603 i8* getelementptr ([6 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1604 { }* null,
1605 int 0,
1606 uint 32,
1607 uint 32,
1608 uint 0,
1609 uint 4 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1610%str1 = internal constant [6 x i8] c"float\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1611</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1612</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1613
1614</div>
1615
1616<!-- ======================================================================= -->
1617<div class="doc_subsubsection">
1618 <a name="ccxx_basic_double">double</a>
1619</div>
1620
1621<div class="doc_text">
1622
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1623<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1624<pre>
1625%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1626 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1627 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1628 8* getelementptr ([7 x 8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1629 { }* null,
1630 int 0,
1631 uint 64,
1632 uint 64,
1633 uint 0,
1634 uint 4 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1635%str1 = internal constant [7 x 8] c"double\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1636</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1637</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1638
1639</div>
1640
1641<!-- ======================================================================= -->
1642<div class="doc_subsection">
1643 <a name="ccxx_derived_types">C/C++ derived types</a>
1644</div>
1645
1646<div class="doc_text">
1647
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1648<p>Given the following as an example of C/C++ derived type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1649
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1650<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1651<pre>
1652typedef const int *IntPtr;
1653</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1654</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1655
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1656<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1657
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1658<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1659<pre>
1660;;
1661;; Define the typedef "IntPtr".
1662;;
1663%<a href="#format_derived_type">llvm.dbg.derivedtype1</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1664 uint add(uint 22, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1665 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1666 i8* getelementptr ([7 x 8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1667 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1668 int 1,
1669 uint 0,
1670 uint 0,
1671 uint 0,
1672 { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype2</a> to { }*) }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1673%str1 = internal constant [7 x 8] c"IntPtr\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1674
1675;;
1676;; Define the pointer type.
1677;;
1678%<a href="#format_derived_type">llvm.dbg.derivedtype2</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1679 uint add(uint 15, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1680 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1681 i8* null,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1682 { }* null,
1683 int 0,
1684 uint 32,
1685 uint 32,
1686 uint 0,
1687 { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype3</a> to { }*) }, section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1688
1689;;
1690;; Define the const type.
1691;;
1692%<a href="#format_derived_type">llvm.dbg.derivedtype3</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1693 uint add(uint 38, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1694 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1695 i8* null,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1696 { }* null,
1697 int 0,
1698 uint 0,
1699 uint 0,
1700 uint 0,
1701 { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype1</a> to { }*) }, section "llvm.metadata"
1702
1703;;
1704;; Define the int type.
1705;;
1706%<a href="#format_basic_type">llvm.dbg.basictype1</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1707 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1708 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1709 8* getelementptr ([4 x 8]* %str2, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1710 { }* null,
1711 int 0,
1712 uint 32,
1713 uint 32,
1714 uint 0,
1715 uint 5 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1716%str2 = internal constant [4 x 8] c"int\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1717</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1718</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1719
1720</div>
1721
1722<!-- ======================================================================= -->
1723<div class="doc_subsection">
1724 <a name="ccxx_composite_types">C/C++ struct/union types</a>
1725</div>
1726
1727<div class="doc_text">
1728
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1729<p>Given the following as an example of C/C++ struct type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1730
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1731<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1732<pre>
1733struct Color {
1734 unsigned Red;
1735 unsigned Green;
1736 unsigned Blue;
1737};
1738</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1739</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1740
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1741<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1742
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1743<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1744<pre>
1745;;
1746;; Define basic type for unsigned int.
1747;;
1748%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1749 uint add(uint 36, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1750 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1751 i8* getelementptr ([13 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1752 { }* null,
1753 int 0,
1754 uint 32,
1755 uint 32,
1756 uint 0,
1757 uint 7 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1758%str1 = internal constant [13 x i8] c"unsigned int\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1759
1760;;
1761;; Define composite type for struct Color.
1762;;
1763%<a href="#format_composite_type">llvm.dbg.compositetype</a> = internal constant %<a href="#format_composite_type">llvm.dbg.compositetype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1764 uint add(uint 19, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1765 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1766 i8* getelementptr ([6 x i8]* %str2, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1767 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1768 int 1,
1769 uint 96,
1770 uint 32,
1771 uint 0,
Jim Laskeyf8a01a92006-06-15 20:51:43 +0000[diff] [blame]1772 { }* null,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1773 { }* cast ([3 x { }*]* %llvm.dbg.array to { }*) }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1774%str2 = internal constant [6 x i8] c"Color\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1775
1776;;
1777;; Define the Red field.
1778;;
1779%<a href="#format_derived_type">llvm.dbg.derivedtype1</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1780 uint add(uint 13, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1781 { }* null,
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1782 i8* getelementptr ([4 x i8]* %str3, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1783 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1784 int 2,
1785 uint 32,
1786 uint 32,
1787 uint 0,
1788 { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1789%str3 = internal constant [4 x i8] c"Red\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1790
1791;;
1792;; Define the Green field.
1793;;
1794%<a href="#format_derived_type">llvm.dbg.derivedtype2</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1795 uint add(uint 13, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1796 { }* null,
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1797 i8* getelementptr ([6 x i8]* %str4, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1798 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1799 int 3,
1800 uint 32,
1801 uint 32,
1802 uint 32,
1803 { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1804%str4 = internal constant [6 x i8] c"Green\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1805
1806;;
1807;; Define the Blue field.
1808;;
1809%<a href="#format_derived_type">llvm.dbg.derivedtype3</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1810 uint add(uint 13, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1811 { }* null,
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1812 i8* getelementptr ([5 x i8]* %str5, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1813 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1814 int 4,
1815 uint 32,
1816 uint 32,
1817 uint 64,
1818 { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1819%str5 = internal constant [5 x 8] c"Blue\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1820
1821;;
1822;; Define the array of fields used by the composite type Color.
1823;;
1824%llvm.dbg.array = internal constant [3 x { }*] [
1825 { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype1</a> to { }*),
1826 { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype2</a> to { }*),
1827 { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype3</a> to { }*) ], section "llvm.metadata"
1828</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1829</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1830
1831</div>
1832
1833<!-- ======================================================================= -->
1834<div class="doc_subsection">
1835 <a name="ccxx_enumeration_types">C/C++ enumeration types</a>
1836</div>
1837
1838<div class="doc_text">
1839
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1840<p>Given the following as an example of C/C++ enumeration type:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1841
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1842<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1843<pre>
1844enum Trees {
1845 Spruce = 100,
1846 Oak = 200,
1847 Maple = 300
1848};
1849</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1850</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1851
Misha Brukman96e00812008-12-16 02:54:22 +0000[diff] [blame]1852<p>a C/C++ front-end would generate the following descriptors:</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1853
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1854<div class="doc_code">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1855<pre>
1856;;
1857;; Define composite type for enum Trees
1858;;
1859%<a href="#format_composite_type">llvm.dbg.compositetype</a> = internal constant %<a href="#format_composite_type">llvm.dbg.compositetype.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1860 uint add(uint 4, uint 262144),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1861 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1862 i8* getelementptr ([6 x i8]* %str1, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1863 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1864 int 1,
1865 uint 32,
1866 uint 32,
1867 uint 0,
1868 { }* null,
1869 { }* cast ([3 x { }*]* %llvm.dbg.array to { }*) }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1870%str1 = internal constant [6 x i8] c"Trees\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1871
1872;;
1873;; Define Spruce enumerator.
1874;;
1875%<a href="#format_enumeration">llvm.dbg.enumerator1</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1876 uint add(uint 40, uint 262144),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1877 i8* getelementptr ([7 x i8]* %str2, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1878 int 100 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1879%str2 = internal constant [7 x i8] c"Spruce\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1880
1881;;
1882;; Define Oak enumerator.
1883;;
1884%<a href="#format_enumeration">llvm.dbg.enumerator2</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1885 uint add(uint 40, uint 262144),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1886 i8* getelementptr ([4 x i8]* %str3, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1887 int 200 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1888%str3 = internal constant [4 x i8] c"Oak\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1889
1890;;
1891;; Define Maple enumerator.
1892;;
1893%<a href="#format_enumeration">llvm.dbg.enumerator3</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> {
Jim Laskey7089f452006-06-16 13:14:03 +0000[diff] [blame]1894 uint add(uint 40, uint 262144),
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1895 i8* getelementptr ([6 x i8]* %str4, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1896 int 300 }, section "llvm.metadata"
Chris Lattnerf436fed2009-04-03 00:29:19 +0000[diff] [blame]1897%str4 = internal constant [6 x i8] c"Maple\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1898
1899;;
1900;; Define the array of enumerators used by composite type Trees.
1901;;
1902%llvm.dbg.array = internal constant [3 x { }*] [
1903 { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator1</a> to { }*),
1904 { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator2</a> to { }*),
1905 { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator3</a> to { }*) ], section "llvm.metadata"
1906</pre>
Bill Wendling48839d92009-05-17 05:52:39 +0000[diff] [blame^]1907</div>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1908
1909</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1910
1911<!-- *********************************************************************** -->
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1912
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1913<hr>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1914<address>
1915 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]1916 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1917 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman44408702008-12-11 17:34:48 +0000[diff] [blame]1918 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]1919
1920 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencer05fe4b02006-03-14 05:39:39 +0000[diff] [blame]1921 <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1922 Last modified: $Date$
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]1923</address>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1924
1925</body>
1926</html>