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9
10<div class="doc_title">Source Level Debugging with LLVM</div>
11
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]12<table class="layout" style="width:100%">
13 <tr class="layout">
14 <td class="left">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]15<ul>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]16 <li><a href="#introduction">Introduction</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]17 <ol>
18 <li><a href="#phil">Philosophy behind LLVM debugging information</a></li>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]19 <li><a href="#consumers">Debug information consumers</a></li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]20 <li><a href="#debugopt">Debugging optimized code</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]21 </ol></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]22 <li><a href="#format">Debugging information format</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]23 <ol>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]24 <li><a href="#debug_info_descriptors">Debug information descriptors</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]25 <ul>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]26 <li><a href="#format_anchors">Anchor descriptors</a></li>
27 <li><a href="#format_compile_units">Compile unit descriptors</a></li>
28 <li><a href="#format_global_variables">Global variable descriptors</a></li>
29 <li><a href="#format_subprograms">Subprogram descriptors</a></li>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]30 <li><a href="#format_blocks">Block descriptors</a></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]31 <li><a href="#format_basic_type">Basic type descriptors</a></li>
32 <li><a href="#format_derived_type">Derived type descriptors</a></li>
33 <li><a href="#format_composite_type">Composite type descriptors</a></li>
34 <li><a href="#format_subrange">Subrange descriptors</a></li>
35 <li><a href="#format_enumeration">Enumerator descriptors</a></li>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]36 <li><a href="#format_variables">Local variables</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]37 </ul></li>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]38 <li><a href="#format_common_intrinsics">Debugger intrinsic functions</a>
39 <ul>
40 <li><a href="#format_common_stoppoint">llvm.dbg.stoppoint</a></li>
41 <li><a href="#format_common_func_start">llvm.dbg.func.start</a></li>
42 <li><a href="#format_common_region_start">llvm.dbg.region.start</a></li>
43 <li><a href="#format_common_region_end">llvm.dbg.region.end</a></li>
44 <li><a href="#format_common_declare">llvm.dbg.declare</a></li>
45 </ul></li>
46 <li><a href="#format_common_stoppoints">Representing stopping points in the
47 source program</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]48 </ol></li>
49 <li><a href="#ccxx_frontend">C/C++ front-end specific debug information</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]50 <ol>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]51 <li><a href="#ccxx_compile_units">C/C++ source file information</a></li>
52 <li><a href="#ccxx_global_variable">C/C++ global variable information</a></li>
53 <li><a href="#ccxx_subprogram">C/C++ function information</a></li>
54 <li><a href="#ccxx_basic_types">C/C++ basic types</a></li>
55 <li><a href="#ccxx_derived_types">C/C++ derived types</a></li>
56 <li><a href="#ccxx_composite_types">C/C++ struct/union types</a></li>
57 <li><a href="#ccxx_enumeration_types">C/C++ enumeration types</a></li>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]58 </ol></li>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]59</ul>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]60</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]61<td class="right">
Misha Brukmane849a1a2004-05-12 21:26:16 +0000[diff] [blame]62<img src="img/venusflytrap.jpg" alt="A leafy and green bug eater" width="247"
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]63height="369">
64</td>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]65</tr></table>
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]66
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]67<div class="doc_author">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]68 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
69 and <a href="mailto:jlaskey@apple.com">Jim Laskey</a></p>
Chris Lattner7911ce22004-05-23 21:07:27 +0000[diff] [blame]70</div>
71
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]72
73<!-- *********************************************************************** -->
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]74<div class="doc_section"><a name="introduction">Introduction</a></div>
75<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]76
77<div class="doc_text">
78
79<p>This document is the central repository for all information pertaining to
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]80debug information in LLVM. It describes the <a href="#format">actual format
81that the LLVM debug information</a> takes, which is useful for those interested
82in creating front-ends or dealing directly with the information. Further, this
83document provides specifc examples of what debug information for C/C++.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]84
85</div>
86
87<!-- ======================================================================= -->
88<div class="doc_subsection">
89 <a name="phil">Philosophy behind LLVM debugging information</a>
90</div>
91
92<div class="doc_text">
93
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]94<p>The idea of the LLVM debugging information is to capture how the important
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]95pieces of the source-language's Abstract Syntax Tree map onto LLVM code.
96Several design aspects have shaped the solution that appears here. The
97important ones are:</p>
98
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]99<ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]100<li>Debugging information should have very little impact on the rest of the
101compiler. No transformations, analyses, or code generators should need to be
102modified because of debugging information.</li>
103
104<li>LLVM optimizations should interact in <a href="#debugopt">well-defined and
105easily described ways</a> with the debugging information.</li>
106
107<li>Because LLVM is designed to support arbitrary programming languages,
108LLVM-to-LLVM tools should not need to know anything about the semantics of the
109source-level-language.</li>
110
111<li>Source-level languages are often <b>widely</b> different from one another.
112LLVM should not put any restrictions of the flavor of the source-language, and
113the debugging information should work with any language.</li>
114
115<li>With code generator support, it should be possible to use an LLVM compiler
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]116to compile a program to native machine code and standard debugging formats.
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]117This allows compatibility with traditional machine-code level debuggers, like
118GDB or DBX.</li>
119
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]120</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]121
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]122<p>The approach used by the LLVM implementation is to use a small set of <a
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]123href="#format_common_intrinsics">intrinsic functions</a> to define a mapping
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]124between LLVM program objects and the source-level objects. The description of
125the source-level program is maintained in LLVM global variables in an <a
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]126href="#ccxx_frontend">implementation-defined format</a> (the C/C++ front-end
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]127currently uses working draft 7 of the <a
128href="http://www.eagercon.com/dwarf/dwarf3std.htm">Dwarf 3 standard</a>).</p>
129
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]130<p>When a program is being debugged, a debugger interacts with the user and
131turns the stored debug information into source-language specific information.
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]132As such, a debugger must be aware of the source-language, and is thus tied to
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]133a specific language of family of languages.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]134
135</div>
136
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]137<!-- ======================================================================= -->
138<div class="doc_subsection">
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]139 <a name="consumers">Debug information consumers</a>
140</div>
141
142<div class="doc_text">
143<p>The role of debug information is to provide meta information normally
144stripped away during the compilation process. This meta information provides an
145llvm user a relationship between generated code and the original program source
146code.</p>
147
148<p>Currently, debug information is consumed by the DwarfWriter to produce dwarf
149information used by the gdb debugger. Other targets could use the same
150information to produce stabs or other debug forms.</p>
151
152<p>It would also be reasonable to use debug information to feed profiling tools
153for analysis of generated code, or, tools for reconstructing the original source
154from generated code.</p>
155
156<p>TODO - expound a bit more.</p>
157
158</div>
159
160<!-- ======================================================================= -->
161<div class="doc_subsection">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]162 <a name="debugopt">Debugging optimized code</a>
163</div>
164
165<div class="doc_text">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]166
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]167<p>An extremely high priority of LLVM debugging information is to make it
168interact well with optimizations and analysis. In particular, the LLVM debug
169information provides the following guarantees:</p>
170
171<ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]172
173<li>LLVM debug information <b>always provides information to accurately read the
174source-level state of the program</b>, regardless of which LLVM optimizations
175have been run, and without any modification to the optimizations themselves.
176However, some optimizations may impact the ability to modify the current state
177of the program with a debugger, such as setting program variables, or calling
178function that have been deleted.</li>
179
180<li>LLVM optimizations gracefully interact with debugging information. If they
181are not aware of debug information, they are automatically disabled as necessary
182in the cases that would invalidate the debug info. This retains the LLVM
183features making it easy to write new transformations.</li>
184
185<li>As desired, LLVM optimizations can be upgraded to be aware of the LLVM
186debugging information, allowing them to update the debugging information as they
187perform aggressive optimizations. This means that, with effort, the LLVM
188optimizers could optimize debug code just as well as non-debug code.</li>
189
190<li>LLVM debug information does not prevent many important optimizations from
191happening (for example inlining, basic block reordering/merging/cleanup, tail
192duplication, etc), further reducing the amount of the compiler that eventually
193is "aware" of debugging information.</li>
194
195<li>LLVM debug information is automatically optimized along with the rest of the
196program, using existing facilities. For example, duplicate information is
197automatically merged by the linker, and unused information is automatically
198removed.</li>
199
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]200</ul>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]201
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]202<p>Basically, the debug information allows you to compile a program with
203"<tt>-O0 -g</tt>" and get full debug information, allowing you to arbitrarily
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]204modify the program as it executes from a debugger. Compiling a program with
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]205"<tt>-O3 -g</tt>" gives you full debug information that is always available and
206accurate for reading (e.g., you get accurate stack traces despite tail call
207elimination and inlining), but you might lose the ability to modify the program
208and call functions where were optimized out of the program, or inlined away
209completely.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]210
211</div>
212
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]213<!-- *********************************************************************** -->
214<div class="doc_section">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]215 <a name="format">Debugging information format</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]216</div>
217<!-- *********************************************************************** -->
218
219<div class="doc_text">
220
221<p>LLVM debugging information has been carefully designed to make it possible
222for the optimizer to optimize the program and debugging information without
223necessarily having to know anything about debugging information. In particular,
224the global constant merging pass automatically eliminates duplicated debugging
225information (often caused by header files), the global dead code elimination
226pass automatically deletes debugging information for a function if it decides to
227delete the function, and the linker eliminates debug information when it merges
228<tt>linkonce</tt> functions.</p>
229
230<p>To do this, most of the debugging information (descriptors for types,
231variables, functions, source files, etc) is inserted by the language front-end
232in the form of LLVM global variables. These LLVM global variables are no
233different from any other global variables, except that they have a web of LLVM
234intrinsic functions that point to them. If the last references to a particular
235piece of debugging information are deleted (for example, by the
236<tt>-globaldce</tt> pass), the extraneous debug information will automatically
237become dead and be removed by the optimizer.</p>
238
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]239<p>Debug information is designed to be agnostic about the target debugger and
240debugging information representation (e.g. DWARF/Stabs/etc). It uses a generic
241machine debug information pass to decode the information that represents
242variables, types, functions, namespaces, etc: this allows for arbitrary
243source-language semantics and type-systems to be used, as long as there is a
244module written for the target debugger to interpret the information. In
245addition, debug global variables are declared in the <tt>"llvm.metadata"</tt>
246section. All values declared in this section are stripped away after target
247debug information is constructed and before the program object is emitted.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]248
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]249<p>To provide basic functionality, the LLVM debugger does have to make some
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]250assumptions about the source-level language being debugged, though it keeps
251these to a minimum. The only common features that the LLVM debugger assumes
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]252exist are <a href="#format_compile_units">source files</a>, and <a
253href="#format_global_variables">program objects</a>. These abstract objects are
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]254used by a debugger to form stack traces, show information about local
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]255variables, etc.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]256
257<p>This section of the documentation first describes the representation aspects
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]258common to any source-language. The <a href="#ccxx_frontend">next section</a>
259describes the data layout conventions used by the C and C++ front-ends.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]260
261</div>
262
263<!-- ======================================================================= -->
264<div class="doc_subsection">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]265 <a name="debug_info_descriptors">Debug information descriptors</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]266</div>
267
268<div class="doc_text">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]269<p>In consideration of the complexity and volume of debug information, LLVM
270provides a specification for well formed debug global variables. The constant
271value of each of these globals is one of a limited set of structures, known as
272debug descriptors.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]273
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]274<p>Consumers of LLVM debug information expect the descriptors for program
275objects to start in a canonical format, but the descriptors can include
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]276additional information appended at the end that is source-language specific. All
277LLVM debugging information is versioned, allowing backwards compatibility in the
278case that the core structures need to change in some way. Also, all debugging
279information objects start with a tag to indicate what type of object it is. The
280source-language is allowed to define its own objects, by using unreserved tag
281numbers. We recommend using with tags in the range 0x1000 thru 0x2000 (there is
282a defined enum DW_TAG_user_base = 0x1000.)</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]283
284<p>The fields of debug descriptors used internally by LLVM (MachineDebugInfo)
285are restricted to only the simple data types <tt>int</tt>, <tt>uint</tt>,
286<tt>bool</tt>, <tt>float</tt>, <tt>double</tt>, <tt>sbyte*</tt> and <tt> { }*
287</tt>. References to arbitrary values are handled using a <tt> { }* </tt> and a
288cast to <tt> { }* </tt> expression; typically references to other field
289descriptors, arrays of descriptors or global variables.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]290
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]291<pre>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]292 %llvm.dbg.object.type = type {
293 uint, ;; A tag
294 ...
295 }
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]296</pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]297
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]298<p>The first field of a descriptor is always an <tt>uint</tt> containing a tag
299value identifying the content of the descriptor. The remaining fields are
300specific to the descriptor. The values of tags are loosely bound to the tag
301values of Dwarf information entries. However, that does not restrict the use of
302the information supplied to Dwarf targets.</p>
303
304<p>The details of the various descriptors follow.</p>
305
306</div>
307
308<!-- ======================================================================= -->
309<div class="doc_subsubsection">
310 <a name="format_anchors">Anchor descriptors</a>
311</div>
312
313<div class="doc_text">
314
315<pre>
316 %<a href="#format_anchors">llvm.dbg.anchor.type</a> = type {
317 uint, ;; Tag = 0
318 uint ;; Tag of descriptors grouped by the anchor
319 }
320</pre>
321
322<p>One important aspect of the LLVM debug representation is that it allows the
323LLVM debugger to efficiently index all of the global objects without having the
324scan the program. To do this, all of the global objects use "anchor"
325descriptors with designated names. All of the global objects of a particular
326type (e.g., compile units) contain a pointer to the anchor. This pointer allows
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]327a debugger to use def-use chains to find all global objects of that type.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]328
329<p>The following names are recognized as anchors by LLVM:</p>
330
331<pre>
332 %<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 } ;; DW_TAG_compile_unit
333 %<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 } ;; DW_TAG_variable
334 %<a href="#format_subprograms">llvm.dbg.subprograms</a> = linkonce constant %<a href="#format_anchors">llvm.dbg.anchor.type</a> { uint 0, uint 46 } ;; DW_TAG_subprogram
335</pre>
336
337<p>Using anchors in this way (where the compile unit descriptor points to the
338anchors, as opposed to having a list of compile unit descriptors) allows for the
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]339standard dead global elimination and merging passes to automatically remove
340unused debugging information. If the globals were kept track of through lists,
341there would always be an object pointing to the descriptors, thus would never be
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]342deleted.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]343
344</div>
345
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]346<!-- ======================================================================= -->
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]347<div class="doc_subsubsection">
348 <a name="format_compile_units">Compile unit descriptors</a>
349</div>
350
351<div class="doc_text">
352
353<pre>
354 %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = type {
355 uint, ;; Tag = 17 (DW_TAG_compile_unit)
356 { }*, ;; Compile unit anchor = cast = (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_units</a> to { }*)
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]357 uint, ;; LLVM debug version number = 3
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]358 uint, ;; Dwarf language identifier (ex. DW_LANG_C89)
359 sbyte*, ;; Source file name
360 sbyte*, ;; Source file directory (includes trailing slash)
361 sbyte* ;; Producer (ex. "4.0.1 LLVM (LLVM research group)")
362 }
363</pre>
364
365<p>These descriptors contain the version number for the debug info (currently
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]3663), a source language ID for the file (we use the Dwarf 3.0 ID numbers, such as
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]367<tt>DW_LANG_C89</tt>, <tt>DW_LANG_C_plus_plus</tt>, <tt>DW_LANG_Cobol74</tt>,
368etc), three strings describing the filename, working directory of the compiler,
369and an identifier string for the compiler that produced it.</p>
370
371<p> Compile unit descriptors provide the root context for objects declared in a
372specific source file. Global variables and top level functions would be defined
373using this context. Compile unit descriptors also provide context for source
374line correspondence.</p>
375
376</div>
377
378<!-- ======================================================================= -->
379<div class="doc_subsubsection">
380 <a name="format_global_variables">Global variable descriptors</a>
381</div>
382
383<div class="doc_text">
384
385<pre>
386 %<a href="#format_global_variables">llvm.dbg.global_variable.type</a> = type {
387 uint, ;; Tag = 52 (DW_TAG_variable)
388 { }*, ;; Global variable anchor = cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_global_variables">llvm.dbg.global_variables</a> to { }*),
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]389 { }*, ;; Reference to context descriptor
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]390 sbyte*, ;; Name
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]391 { }*, ;; Reference to compile unit where defined
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]392 uint, ;; Line number where defined
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]393 { }*, ;; Reference to type descriptor
394 bool, ;; True if the global is local to compile unit (static)
395 bool, ;; True if the global is defined in the compile unit (not extern)
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]396 { }* ;; Reference to the global variable
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]397 }
398</pre>
399
400<p>These descriptors provide debug information about globals variables. The
401provide details such as name, type and where the variable is defined.</p>
402
403</div>
404
405<!-- ======================================================================= -->
406<div class="doc_subsubsection">
407 <a name="format_subprograms">Subprogram descriptors</a>
408</div>
409
410<div class="doc_text">
411
412<pre>
413 %<a href="#format_subprograms">llvm.dbg.subprogram.type</a> = type {
414 uint, ;; Tag = 46 (DW_TAG_subprogram)
415 { }*, ;; Subprogram anchor = cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_subprograms">llvm.dbg.subprograms</a> to { }*),
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]416 { }*, ;; Reference to context descriptor
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]417 sbyte*, ;; Name
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]418 { }*, ;; Reference to compile unit where defined
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]419 uint, ;; Line number where defined
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]420 { }*, ;; Reference to type descriptor
421 bool, ;; True if the global is local to compile unit (static)
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]422 bool ;; True if the global is defined in the compile unit (not extern)
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]423 }
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]424</pre>
425
426<p>These descriptors provide debug information about functions, methods and
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]427subprograms. They provide details such as name, return types and the source
428location where the subprogram is defined.</p>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]429
430</div>
431<!-- ======================================================================= -->
432<div class="doc_subsubsection">
433 <a name="format_blocks">Block descriptors</a>
434</div>
435
436<div class="doc_text">
437
438<pre>
439 %<a href="#format_blocks">llvm.dbg.block</a> = type {
440 uint, ;; Tag = 13 (DW_TAG_lexical_block)
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]441 { }* ;; Reference to context descriptor
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]442 }
443</pre>
444
445<p>These descriptors provide debug information about nested blocks within a
446subprogram. The array of member descriptors is used to define local variables
447and deeper nested blocks.</p>
448
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]449</div>
450
451<!-- ======================================================================= -->
452<div class="doc_subsubsection">
453 <a name="format_basic_type">Basic type descriptors</a>
454</div>
455
456<div class="doc_text">
457
458<pre>
459 %<a href="#format_basic_type">llvm.dbg.basictype.type</a> = type {
460 uint, ;; Tag = 36 (DW_TAG_base_type)
461 { }*, ;; Reference to context (typically a compile unit)
462 sbyte*, ;; Name (may be "" for anonymous types)
463 { }*, ;; Reference to compile unit where defined (may be NULL)
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]464 uint, ;; Line number where defined (may be 0)
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]465 uint, ;; Size in bits
466 uint, ;; Alignment in bits
467 uint, ;; Offset in bits
468 uint ;; Dwarf type encoding
469 }
470</pre>
471
472<p>These descriptors define primitive types used in the code. Example int, bool
473and float. The context provides the scope of the type, which is usually the top
474level. Since basic types are not usually user defined the compile unit and line
475number can be left as NULL and 0. The size, alignment and offset are expressed
476in bits and can be 64 bit values. The alignment is used to round the offset
477when embedded in a <a href="#format_composite_type">composite type</a>
478(example to keep float doubles on 64 bit boundaries.) The offset is the bit
479offset if embedded in a <a href="#format_composite_type">composite
480type</a>.</p>
481
482<p>The type encoding provides the details of the type. The values are typically
483one of the following;</p>
484
485<pre>
486 DW_ATE_address = 1
487 DW_ATE_boolean = 2
488 DW_ATE_float = 4
489 DW_ATE_signed = 5
490 DW_ATE_signed_char = 6
491 DW_ATE_unsigned = 7
492 DW_ATE_unsigned_char = 8
493</pre>
494
495</div>
496
497<!-- ======================================================================= -->
498<div class="doc_subsubsection">
499 <a name="format_derived_type">Derived type descriptors</a>
500</div>
501
502<div class="doc_text">
503
504<pre>
505 %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> = type {
506 uint, ;; Tag (see below)
507 { }*, ;; Reference to context
508 sbyte*, ;; Name (may be "" for anonymous types)
509 { }*, ;; Reference to compile unit where defined (may be NULL)
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]510 uint, ;; Line number where defined (may be 0)
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]511 uint, ;; Size in bits
512 uint, ;; Alignment in bits
513 uint, ;; Offset in bits
514 { }* ;; Reference to type derived from
515 }
516</pre>
517
518<p>These descriptors are used to define types derived from other types. The
519value of the tag varies depending on the meaning. The following are possible
520tag values;</p>
521
522<pre>
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]523 DW_TAG_formal_parameter = 5
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]524 DW_TAG_member = 13
525 DW_TAG_pointer_type = 15
526 DW_TAG_reference_type = 16
527 DW_TAG_typedef = 22
528 DW_TAG_const_type = 38
529 DW_TAG_volatile_type = 53
530 DW_TAG_restrict_type = 55
531</pre>
532
533<p> <tt>DW_TAG_member</tt> is used to define a member of a <a
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]534href="#format_composite_type">composite type</a> or <a
535href="#format_subprograms">subprogram</a>. The type of the member is the <a
536href="#format_derived_type">derived type</a>. <tt>DW_TAG_formal_parameter</tt>
537is used to define a member which is a formal argument of a subprogram.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]538
539<p><tt>DW_TAG_typedef</tt> is used to
540provide a name for the derived type.</p>
541
542<p><tt>DW_TAG_pointer_type</tt>,
543<tt>DW_TAG_reference_type</tt>, <tt>DW_TAG_const_type</tt>,
544<tt>DW_TAG_volatile_type</tt> and <tt>DW_TAG_restrict_type</tt> are used to
545qualify the <a href="#format_derived_type">derived type</a>. </p>
546
547<p><a href="#format_derived_type">Derived type</a> location can be determined
548from the compile unit and line number. The size, alignment and offset are
549expressed in bits and can be 64 bit values. The alignment is used to round the
550offset when embedded in a <a href="#format_composite_type">composite type</a>
551(example to keep float doubles on 64 bit boundaries.) The offset is the bit
552offset if embedded in a <a href="#format_composite_type">composite
553type</a>.</p>
554
555<p>Note that the <tt>void *</tt> type is expressed as a
556<tt>llvm.dbg.derivedtype.type</tt> with tag of <tt>DW_TAG_pointer_type</tt> and
557NULL derived type.</p>
558
559</div>
560
561<!-- ======================================================================= -->
562<div class="doc_subsubsection">
563 <a name="format_composite_type">Composite type descriptors</a>
564</div>
565
566<div class="doc_text">
567
568<pre>
569 %<a href="#format_composite_type">llvm.dbg.compositetype.type</a> = type {
570 uint, ;; Tag (see below)
571 { }*, ;; Reference to context
572 sbyte*, ;; Name (may be "" for anonymous types)
573 { }*, ;; Reference to compile unit where defined (may be NULL)
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]574 uint, ;; Line number where defined (may be 0)
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]575 uint, ;; Size in bits
576 uint, ;; Alignment in bits
577 uint, ;; Offset in bits
Jim Laskeyf8a01a92006-06-15 20:51:43 +0000[diff] [blame^]578 bool, ;; Is vector flag
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]579 { }* ;; Reference to array of member descriptors
580 }
581</pre>
582
583<p>These descriptors are used to define types that are composed of 0 or more
584elements. The value of the tag varies depending on the meaning. The following
585are possible tag values;</p>
586
587<pre>
588 DW_TAG_array_type = 1
589 DW_TAG_enumeration_type = 4
590 DW_TAG_structure_type = 19
591 DW_TAG_union_type = 23
592</pre>
593
Jim Laskeyf8a01a92006-06-15 20:51:43 +0000[diff] [blame^]594<p>The vector flag indicates that an array type is a native packed vector.</p>
595
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]596<p>The members of array types (tag = <tt>DW_TAG_array_type</tt>) are <a
597href="#format_subrange">subrange descriptors</a>, each representing the range of
598subscripts at that level of indexing.</p>
599
600<p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are
601<a href="#format_enumeration">enumerator descriptors</a>, each representing the
602definition of enumeration value
603for the set.</p>
604
605<p>The members of structure (tag = <tt>DW_TAG_structure_type</tt>) or union (tag
606= <tt>DW_TAG_union_type</tt>) types are any one of the <a
607href="#format_basic_type">basic</a>, <a href="#format_derived_type">derived</a>
608or <a href="#format_composite_type">composite</a> type descriptors, each
609representing a field member of the structure or union.</p>
610
611<p><a href="#format_composite_type">Composite type</a> location can be
612determined from the compile unit and line number. The size, alignment and
613offset are expressed in bits and can be 64 bit values. The alignment is used to
614round the offset when embedded in a <a href="#format_composite_type">composite
615type</a> (as an example, to keep float doubles on 64 bit boundaries.) The offset
616is the bit offset if embedded in a <a href="#format_composite_type">composite
617type</a>.</p>
618
619</div>
620
621<!-- ======================================================================= -->
622<div class="doc_subsubsection">
623 <a name="format_subrange">Subrange descriptors</a>
624</div>
625
626<div class="doc_text">
627
628<pre>
629 %<a href="#format_subrange">llvm.dbg.subrange.type</a> = type {
630 uint, ;; Tag = 33 (DW_TAG_subrange_type)
631 uint, ;; Low value
632 uint ;; High value
633 }
634</pre>
635
636<p>These descriptors are used to define ranges of array subscripts for an array
637<a href="#format_composite_type">composite type</a>. The low value defines the
638lower bounds typically zero for C/C++. The high value is the upper bounds.
639Values are 64 bit. High - low + 1 is the size of the array. If
640low == high the array will be unbounded.</p>
641
642</div>
643
644<!-- ======================================================================= -->
645<div class="doc_subsubsection">
646 <a name="format_enumeration">Enumerator descriptors</a>
647</div>
648
649<div class="doc_text">
650
651<pre>
652 %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> = type {
653 uint, ;; Tag = 40 (DW_TAG_enumerator)
654 sbyte*, ;; Name
655 uint ;; Value
656 }
657</pre>
658
659<p>These descriptors are used to define members of an enumeration <a
660href="#format_composite_type">composite type</a>, it associates the name to the
661value.</p>
662
663</div>
664
665<!-- ======================================================================= -->
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]666<div class="doc_subsubsection">
667 <a name="format_variables">Local variables</a>
668</div>
669
670<div class="doc_text">
671<pre>
672 %<a href="#format_variables">llvm.dbg.variable.type</a> = type {
673 uint, ;; Tag (see below)
674 { }*, ;; Context
675 sbyte*, ;; Name
676 { }*, ;; Reference to compile unit where defined
677 uint, ;; Line number where defined
678 { }* ;; Type descriptor
679 }
680</pre>
681
682<p>These descriptors are used to define variables local to a sub program. The
683value of the tag depends on the usage of the variable;</p>
684
685<pre>
686 DW_TAG_auto_variable = 256
687 DW_TAG_arg_variable = 257
688 DW_TAG_return_variable = 258
689</pre>
690
691<p>An auto variable is any variable declared in the body of the function. An
692argument variable is any variable that appears as a formal argument to the
693function. A return variable is used to track the result of a function and has
694no source correspondent.</p>
695
Jim Laskey2d395d92006-03-24 09:20:27 +0000[diff] [blame]696<p>The context is either the subprogram or block where the variable is defined.
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]697Name the source variable name. Compile unit and line indicate where the
698variable was defined. Type descriptor defines the declared type of the
699variable.</p>
700
701</div>
702
703<!-- ======================================================================= -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]704<div class="doc_subsection">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]705 <a name="format_common_intrinsics">Debugger intrinsic functions</a>
706</div>
707
708<div class="doc_text">
709
710<p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to
711provide debug information at various points in generated code.</p>
712
713</div>
714
715<!-- ======================================================================= -->
716<div class="doc_subsubsection">
717 <a name="format_common_stoppoint">llvm.dbg.stoppoint</a>
718</div>
719
720<div class="doc_text">
721<pre>
Jim Laskey108a6382006-03-23 17:58:46 +0000[diff] [blame]722 void %<a href="#format_common_stoppoint">llvm.dbg.stoppoint</a>( uint, uint, { }* )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]723</pre>
724
725<p>This intrinsic is used to provide correspondence between the source file and
726the generated code. The first argument is the line number (base 1), second
727argument si the column number (0 if unknown) and the third argument the source
Jim Laskey108a6382006-03-23 17:58:46 +0000[diff] [blame]728<tt>%<a href="#format_compile_units">llvm.dbg.compile_unit</a>*</tt> cast to a
729<tt>{ }*</tt>. Code following a call to this intrinsic will have been defined
730in close proximity of the line, column and file. This information holds until
731the next call to <tt>%<a
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]732href="#format_common_stoppoint">lvm.dbg.stoppoint</a></tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]733
734</div>
735
736<!-- ======================================================================= -->
737<div class="doc_subsubsection">
738 <a name="format_common_func_start">llvm.dbg.func.start</a>
739</div>
740
741<div class="doc_text">
742<pre>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]743 void %<a href="#format_common_func_start">llvm.dbg.func.start</a>( { }* )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]744</pre>
745
746<p>This intrinsic is used to link the debug information in <tt>%<a
747href="#format_subprograms">llvm.dbg.subprogram</a></tt> to the function. It also
748defines the beginning of the function's declarative region (scope.) The
749intrinsic should be called early in the function after the all the alloca
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]750instructions. It should be paired off with a closing <tt>%<a
751href="#format_common_region_end">llvm.dbg.region.end</a></tt>. The function's
752single argument is the <tt>%<a
753href="#format_subprograms">llvm.dbg.subprogram.type</a></tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]754
755</div>
756
757<!-- ======================================================================= -->
758<div class="doc_subsubsection">
759 <a name="format_common_region_start">llvm.dbg.region.start</a>
760</div>
761
762<div class="doc_text">
763<pre>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]764 void %<a href="#format_common_region_start">llvm.dbg.region.start</a>( { }* )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]765</pre>
766
767<p>This intrinsic is used to define the beginning of a declarative scope (ex.
768block) for local language elements. It should be paired off with a closing
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]769<tt>%<a href="#format_common_region_end">llvm.dbg.region.end</a></tt>. The
770function's single argument is the <tt>%<a
771href="#format_blocks">llvm.dbg.block</a></tt> which is starting.</p>
772
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]773
774</div>
775
776<!-- ======================================================================= -->
777<div class="doc_subsubsection">
778 <a name="format_common_region_end">llvm.dbg.region.end</a>
779</div>
780
781<div class="doc_text">
782<pre>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]783 void %<a href="#format_common_region_end">llvm.dbg.region.end</a>( { }* )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]784</pre>
785
786<p>This intrinsic is used to define the end of a declarative scope (ex. block)
787for local language elements. It should be paired off with an opening <tt>%<a
788href="#format_common_region_start">llvm.dbg.region.start</a></tt> or <tt>%<a
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]789href="#format_common_func_start">llvm.dbg.func.start</a></tt>. The function's
790single argument is either the <tt>%<a
791href="#format_blocks">llvm.dbg.block</a></tt> or the <tt>%<a
792href="#format_subprograms">llvm.dbg.subprogram.type</a></tt> which is
793ending.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]794
795</div>
796
797<!-- ======================================================================= -->
798<div class="doc_subsubsection">
799 <a name="format_common_declare">llvm.dbg.declare</a>
800</div>
801
802<div class="doc_text">
803<pre>
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]804 void %<a href="#format_common_declare">llvm.dbg.declare</a>( { } *, { }* )
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]805</pre>
806
Jim Laskey2d395d92006-03-24 09:20:27 +0000[diff] [blame]807<p>This intrinsic provides information about a local element (ex. variable.) The
808first argument is the alloca for the variable, cast to a <tt>{ }*</tt>. The
809second argument is the <tt>%<a
810href="#format_variables">llvm.dbg.variable</a></tt> containing the description
811of the variable, also cast to a <tt>{ }*</tt>.</p>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]812
813</div>
814
815<!-- ======================================================================= -->
816<div class="doc_subsection">
817 <a name="format_common_stoppoints">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]818 Representing stopping points in the source program
819 </a>
820</div>
821
822<div class="doc_text">
823
824<p>LLVM debugger "stop points" are a key part of the debugging representation
825that allows the LLVM to maintain simple semantics for <a
826href="#debugopt">debugging optimized code</a>. The basic idea is that the
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]827front-end inserts calls to the <a
828href="#format_common_stoppoint">%<tt>llvm.dbg.stoppoint</tt></a> intrinsic
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]829function at every point in the program where a debugger should be able to
830inspect the program (these correspond to places a debugger stops when you
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]831"<tt>step</tt>" through it). The front-end can choose to place these as
832fine-grained as it would like (for example, before every subexpression
833evaluated), but it is recommended to only put them after every source statement
834that includes executable code.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]835
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]836<p>Using calls to this intrinsic function to demark legal points for the
837debugger to inspect the program automatically disables any optimizations that
838could potentially confuse debugging information. To non-debug-information-aware
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]839transformations, these calls simply look like calls to an external function,
840which they must assume to do anything (including reading or writing to any part
841of reachable memory). On the other hand, it does not impact many optimizations,
842such as code motion of non-trapping instructions, nor does it impact
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]843optimization of subexpressions, code duplication transformations, or basic-block
844reordering transformations.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]845
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]846</div>
847
848
849<!-- ======================================================================= -->
850<div class="doc_subsection">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]851 <a name="format_common_lifetime">Object lifetimes and scoping</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]852</div>
853
854<div class="doc_text">
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]855<p>In many languages, the local variables in functions can have their lifetime
856or scope limited to a subset of a function. In the C family of languages, for
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]857example, variables are only live (readable and writable) within the source block
858that they are defined in. In functional languages, values are only readable
859after they have been defined. Though this is a very obvious concept, it is also
860non-trivial to model in LLVM, because it has no notion of scoping in this sense,
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]861and does not want to be tied to a language's scoping rules.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]862
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]863<p>In order to handle this, the LLVM debug format uses the notion of "regions"
864of a function, delineated by calls to intrinsic functions. These intrinsic
865functions define new regions of the program and indicate when the region
866lifetime expires. Consider the following C fragment, for example:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]867
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]868<pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]8691. void foo() {
8702. int X = ...;
8713. int Y = ...;
8724. {
8735. int Z = ...;
8746. ...
8757. }
8768. ...
8779. }
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]878</pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]879
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]880<p>Compiled to LLVM, this function would be represented like this:</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]881
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]882<pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]883void %foo() {
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]884entry:
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]885 %X = alloca int
886 %Y = alloca int
887 %Z = alloca int
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]888
889 ...
890
891 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 )
892
893 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 )
894
895 call void %<a href="#format_common_declare">llvm.dbg.declare</a>({}* %X, ...)
896 call void %<a href="#format_common_declare">llvm.dbg.declare</a>({}* %Y, ...)
897
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]898 <i>;; Evaluate expression on line 2, assigning to X.</i>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]899
900 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 )
901
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]902 <i>;; Evaluate expression on line 3, assigning to Y.</i>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]903
904 call void %<a href="#format_common_stoppoint">llvm.region.start</a>()
905 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 )
906 call void %<a href="#format_common_declare">llvm.dbg.declare</a>({}* %X, ...)
907
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]908 <i>;; Evaluate expression on line 5, assigning to Z.</i>
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]909
910 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 )
911 call void %<a href="#format_common_region_end">llvm.region.end</a>()
912
913 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 )
914
915 call void %<a href="#format_common_region_end">llvm.region.end</a>()
916
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]917 ret void
918}
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]919</pre>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]920
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]921<p>This example illustrates a few important details about the LLVM debugging
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]922information. In particular, it shows how the various intrinsics are applied
923together to allow a debugger to analyze the relationship between statements,
924variable definitions, and the code used to implement the function.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]925
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]926<p>The first intrinsic <tt>%<a
927href="#format_common_func_start">llvm.dbg.func.start</a></tt> provides
928a link with the <a href="#format_subprograms">subprogram descriptor</a>
929containing the details of this function. This call also defines the beginning
930of the function region, bounded by the <tt>%<a
931href="#format_common_region_end">llvm.region.end</a></tt> at the end of
932the function. This region is used to bracket the lifetime of variables declared
933within. For a function, this outer region defines a new stack frame whose
934lifetime ends when the region is ended.</p>
935
936<p>It is possible to define inner regions for short term variables by using the
937%<a href="#format_common_stoppoint"><tt>llvm.region.start</tt></a> and <a
938href="#format_common_region_end"><tt>%llvm.region.end</tt></a> to bound a
939region. The inner region in this example would be for the block containing the
940declaration of Z.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]941
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]942<p>Using regions to represent the boundaries of source-level functions allow
943LLVM interprocedural optimizations to arbitrarily modify LLVM functions without
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]944having to worry about breaking mapping information between the LLVM code and the
945and source-level program. In particular, the inliner requires no modification
946to support inlining with debugging information: there is no explicit correlation
947drawn between LLVM functions and their source-level counterparts (note however,
948that if the inliner inlines all instances of a non-strong-linkage function into
949its caller that it will not be possible for the user to manually invoke the
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]950inlined function from a debugger).</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]951
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]952<p>Once the function has been defined, the <a
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]953href="#format_common_stoppoint"><tt>stopping point</tt></a> corresponding to
954line #2 (column #2) of the function is encountered. At this point in the
955function, <b>no</b> local variables are live. As lines 2 and 3 of the example
956are executed, their variable definitions are introduced into the program using
957%<a href="#format_common_declare"><tt>llvm.dbg.declare</tt></a>, without the
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]958need to specify a new region. These variables do not require new regions to be
959introduced because they go out of scope at the same point in the program: line
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]9609.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]961
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]962<p>In contrast, the <tt>Z</tt> variable goes out of scope at a different time,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]963on line 7. For this reason, it is defined within the inner region, which kills
964the availability of <tt>Z</tt> before the code for line 8 is executed. In this
965way, regions can support arbitrary source-language scoping rules, as long as
966they can only be nested (ie, one scope cannot partially overlap with a part of
967another scope).</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]968
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]969<p>It is worth noting that this scoping mechanism is used to control scoping of
970all declarations, not just variable declarations. For example, the scope of a
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]971C++ using declaration is controlled with this couldchange how name lookup is
972performed.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]973
974</div>
975
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]976
977
978<!-- *********************************************************************** -->
979<div class="doc_section">
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]980 <a name="ccxx_frontend">C/C++ front-end specific debug information</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]981</div>
Misha Brukman94218a72004-12-09 20:27:37 +0000[diff] [blame]982<!-- *********************************************************************** -->
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]983
984<div class="doc_text">
985
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]986<p>The C and C++ front-ends represent information about the program in a format
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]987that is effectively identical to <a
988href="http://www.eagercon.com/dwarf/dwarf3std.htm">Dwarf 3.0</a> in terms of
989information content. This allows code generators to trivially support native
990debuggers by generating standard dwarf information, and contains enough
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]991information for non-dwarf targets to translate it as needed.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]992
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]993<p>This section describes the forms used to represent C and C++ programs. Other
994languages could pattern themselves after this (which itself is tuned to
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]995representing programs in the same way that Dwarf 3 does), or they could choose
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]996to provide completely different forms if they don't fit into the Dwarf model.
997As support for debugging information gets added to the various LLVM
Misha Brukman82873732004-05-12 19:21:57 +0000[diff] [blame]998source-language front-ends, the information used should be documented here.</p>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]999
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1000<p>The following sections provide examples of various C/C++ constructs and the
1001debug information that would best describe those constructs.</p>
1002
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1003</div>
1004
1005<!-- ======================================================================= -->
1006<div class="doc_subsection">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1007 <a name="ccxx_compile_units">C/C++ source file information</a>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1008</div>
1009
1010<div class="doc_text">
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1011
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1012<p>Given the source files "MySource.cpp" and "MyHeader.h" located in the
1013directory "/Users/mine/sources", the following code;</p>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1014
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1015<pre>
1016#include "MyHeader.h"
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1017
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1018int main(int argc, char *argv[]) {
1019 return 0;
1020}
1021</pre>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1022
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1023<p>a C/C++ front-end would generate the following descriptors;</p>
1024
1025<pre>
1026...
1027;;
1028;; Define types used. In this case we need one for compile unit anchors and one
1029;; for compile units.
1030;;
1031%<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint }
1032%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = type { uint, { }*, uint, uint, sbyte*, sbyte*, sbyte* }
1033...
1034;;
1035;; Define the anchor for compile units. Note that the second field of the
1036;; anchor is 17, which is the same as the tag for compile units
1037;; (17 = DW_TAG_compile_unit.)
1038;;
1039%<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"
1040
1041;;
1042;; Define the compile unit for the source file "/Users/mine/sources/MySource.cpp".
1043;;
1044%<a href="#format_compile_units">llvm.dbg.compile_unit1</a> = internal constant %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> {
1045 uint 17,
1046 { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_units</a> to { }*),
1047 uint 1,
1048 uint 1,
1049 sbyte* getelementptr ([13 x sbyte]* %str1, int 0, int 0),
1050 sbyte* getelementptr ([21 x sbyte]* %str2, int 0, int 0),
1051 sbyte* getelementptr ([33 x sbyte]* %str3, int 0, int 0) }, section "llvm.metadata"
1052
1053;;
1054;; Define the compile unit for the header file "/Users/mine/sources/MyHeader.h".
1055;;
1056%<a href="#format_compile_units">llvm.dbg.compile_unit2</a> = internal constant %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> {
1057 uint 17,
1058 { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_units</a> to { }*),
1059 uint 1,
1060 uint 1,
1061 sbyte* getelementptr ([11 x sbyte]* %str4, int 0, int 0),
1062 sbyte* getelementptr ([21 x sbyte]* %str2, int 0, int 0),
1063 sbyte* getelementptr ([33 x sbyte]* %str3, int 0, int 0) }, section "llvm.metadata"
1064
1065;;
1066;; Define each of the strings used in the compile units.
1067;;
1068%str1 = internal constant [13 x sbyte] c"MySource.cpp\00", section "llvm.metadata";
1069%str2 = internal constant [21 x sbyte] c"/Users/mine/sources/\00", section "llvm.metadata";
1070%str3 = internal constant [33 x sbyte] c"4.0.1 LLVM (LLVM research group)\00", section "llvm.metadata";
1071%str4 = internal constant [11 x sbyte] c"MyHeader.h\00", section "llvm.metadata";
1072...
1073</pre>
1074
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1075</div>
1076
1077<!-- ======================================================================= -->
1078<div class="doc_subsection">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1079 <a name="ccxx_global_variable">C/C++ global variable information</a>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1080</div>
1081
1082<div class="doc_text">
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1083
1084<p>Given an integer global variable declared as follows;</p>
1085
1086<pre>
1087int MyGlobal = 100;
1088</pre>
1089
1090<p>a C/C++ front-end would generate the following descriptors;</p>
1091
1092<pre>
1093;;
1094;; Define types used. One for global variable anchors, one for the global
1095;; variable descriptor, one for the global's basic type and one for the global's
1096;; compile unit.
1097;;
1098%<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint }
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]1099%<a href="#format_global_variables">llvm.dbg.global_variable.type</a> = type { uint, { }*, { }*, sbyte*, { }*, uint, { }*, bool, bool, { }*, uint }
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1100%<a href="#format_basic_type">llvm.dbg.basictype.type</a> = type { uint, { }*, sbyte*, { }*, int, uint, uint, uint, uint }
1101%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = ...
1102...
1103;;
1104;; Define the global itself.
1105;;
1106%MyGlobal = global int 100
1107...
1108;;
1109;; Define the anchor for global variables. Note that the second field of the
1110;; anchor is 52, which is the same as the tag for global variables
1111;; (52 = DW_TAG_variable.)
1112;;
1113%<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"
1114
1115;;
1116;; Define the global variable descriptor. Note the reference to the global
1117;; variable anchor and the global variable itself.
1118;;
1119%<a href="#format_global_variables">llvm.dbg.global_variable</a> = internal constant %<a href="#format_global_variables">llvm.dbg.global_variable.type</a> {
1120 uint 52,
1121 { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_global_variables">llvm.dbg.global_variables</a> to { }*),
1122 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1123 sbyte* getelementptr ([9 x sbyte]* %str1, int 0, int 0),
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]1124 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1125 uint 1,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1126 { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*),
1127 bool false,
1128 bool true,
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]1129 { }* cast (int* %MyGlobal to { }*) }, section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1130
1131;;
1132;; Define the basic type of 32 bit signed integer. Note that since int is an
1133;; intrinsic type the source file is NULL and line 0.
1134;;
1135%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1136 uint 36,
1137 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1138 sbyte* getelementptr ([4 x sbyte]* %str2, int 0, int 0),
1139 { }* null,
1140 int 0,
1141 uint 32,
1142 uint 32,
1143 uint 0,
1144 uint 5 }, section "llvm.metadata"
1145
1146;;
1147;; Define the names of the global variable and basic type.
1148;;
1149%str1 = internal constant [9 x sbyte] c"MyGlobal\00", section "llvm.metadata"
1150%str2 = internal constant [4 x sbyte] c"int\00", section "llvm.metadata"
1151</pre>
1152
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]1153</div>
Chris Lattnerbdfb3392004-01-05 05:06:33 +0000[diff] [blame]1154
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1155<!-- ======================================================================= -->
1156<div class="doc_subsection">
1157 <a name="ccxx_subprogram">C/C++ function information</a>
1158</div>
1159
1160<div class="doc_text">
1161
1162<p>Given a function declared as follows;</p>
1163
1164<pre>
1165int main(int argc, char *argv[]) {
1166 return 0;
1167}
1168</pre>
1169
1170<p>a C/C++ front-end would generate the following descriptors;</p>
1171
1172<pre>
1173;;
1174;; Define types used. One for subprogram anchors, one for the subprogram
1175;; descriptor, one for the global's basic type and one for the subprogram's
1176;; compile unit.
1177;;
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]1178%<a href="#format_subprograms">llvm.dbg.subprogram.type</a> = type { uint, { }*, { }*, sbyte*, { }*, bool, bool }
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1179%<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint }
1180%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = ...
1181
1182;;
1183;; Define the anchor for subprograms. Note that the second field of the
1184;; anchor is 46, which is the same as the tag for subprograms
1185;; (46 = DW_TAG_subprogram.)
1186;;
1187%<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"
1188
1189;;
1190;; Define the descriptor for the subprogram. TODO - more details.
1191;;
1192%<a href="#format_subprograms">llvm.dbg.subprogram</a> = internal constant %<a href="#format_subprograms">llvm.dbg.subprogram.type</a> {
1193 uint 46,
1194 { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_subprograms">llvm.dbg.subprograms</a> to { }*),
1195 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1196 sbyte* getelementptr ([5 x sbyte]* %str1, int 0, int 0),
Jim Laskey3d11bee2006-03-15 19:10:52 +0000[diff] [blame]1197 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1198 uint 1,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1199 { }* null,
1200 bool false,
Jim Laskey383e0092006-03-23 17:54:33 +0000[diff] [blame]1201 bool true }, section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1202
1203;;
1204;; Define the name of the subprogram.
1205;;
1206%str1 = internal constant [5 x sbyte] c"main\00", section "llvm.metadata"
1207
1208;;
1209;; Define the subprogram itself.
1210;;
1211int %main(int %argc, sbyte** %argv) {
1212...
1213}
1214</pre>
1215
1216</div>
1217
1218<!-- ======================================================================= -->
1219<div class="doc_subsection">
1220 <a name="ccxx_basic_types">C/C++ basic types</a>
1221</div>
1222
1223<div class="doc_text">
1224
1225<p>The following are the basic type descriptors for C/C++ core types;</p>
1226
1227</div>
1228
1229<!-- ======================================================================= -->
1230<div class="doc_subsubsection">
1231 <a name="ccxx_basic_type_bool">bool</a>
1232</div>
1233
1234<div class="doc_text">
1235
1236<pre>
1237%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1238 uint 36,
1239 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1240 sbyte* getelementptr ([5 x sbyte]* %str1, int 0, int 0),
1241 { }* null,
1242 int 0,
1243 uint 32,
1244 uint 32,
1245 uint 0,
1246 uint 2 }, section "llvm.metadata"
1247%str1 = internal constant [5 x sbyte] c"bool\00", section "llvm.metadata"
1248</pre>
1249
1250</div>
1251
1252<!-- ======================================================================= -->
1253<div class="doc_subsubsection">
1254 <a name="ccxx_basic_char">char</a>
1255</div>
1256
1257<div class="doc_text">
1258
1259<pre>
1260%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1261 uint 36,
1262 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1263 sbyte* getelementptr ([5 x sbyte]* %str1, int 0, int 0),
1264 { }* null,
1265 int 0,
1266 uint 8,
1267 uint 8,
1268 uint 0,
1269 uint 6 }, section "llvm.metadata"
1270%str1 = internal constant [5 x sbyte] c"char\00", section "llvm.metadata"
1271</pre>
1272
1273</div>
1274
1275<!-- ======================================================================= -->
1276<div class="doc_subsubsection">
1277 <a name="ccxx_basic_unsigned_char">unsigned char</a>
1278</div>
1279
1280<div class="doc_text">
1281
1282<pre>
1283%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1284 uint 36,
1285 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1286 sbyte* getelementptr ([14 x sbyte]* %str1, int 0, int 0),
1287 { }* null,
1288 int 0,
1289 uint 8,
1290 uint 8,
1291 uint 0,
1292 uint 8 }, section "llvm.metadata"
1293%str1 = internal constant [14 x sbyte] c"unsigned char\00", section "llvm.metadata"
1294</pre>
1295
1296</div>
1297
1298<!-- ======================================================================= -->
1299<div class="doc_subsubsection">
1300 <a name="ccxx_basic_short">short</a>
1301</div>
1302
1303<div class="doc_text">
1304
1305<pre>
1306%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1307 uint 36,
1308 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1309 sbyte* getelementptr ([10 x sbyte]* %str1, int 0, int 0),
1310 { }* null,
1311 int 0,
1312 uint 16,
1313 uint 16,
1314 uint 0,
1315 uint 5 }, section "llvm.metadata"
1316%str1 = internal constant [10 x sbyte] c"short int\00", section "llvm.metadata"
1317</pre>
1318
1319</div>
1320
1321<!-- ======================================================================= -->
1322<div class="doc_subsubsection">
1323 <a name="ccxx_basic_unsigned_short">unsigned short</a>
1324</div>
1325
1326<div class="doc_text">
1327
1328<pre>
1329%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1330 uint 36,
1331 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1332 sbyte* getelementptr ([19 x sbyte]* %str1, int 0, int 0),
1333 { }* null,
1334 int 0,
1335 uint 16,
1336 uint 16,
1337 uint 0,
1338 uint 7 }, section "llvm.metadata"
1339%str1 = internal constant [19 x sbyte] c"short unsigned int\00", section "llvm.metadata"
1340</pre>
1341
1342</div>
1343
1344<!-- ======================================================================= -->
1345<div class="doc_subsubsection">
1346 <a name="ccxx_basic_int">int</a>
1347</div>
1348
1349<div class="doc_text">
1350
1351<pre>
1352%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1353 uint 36,
1354 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1355 sbyte* getelementptr ([4 x sbyte]* %str1, int 0, int 0),
1356 { }* null,
1357 int 0,
1358 uint 32,
1359 uint 32,
1360 uint 0,
1361 uint 5 }, section "llvm.metadata"
1362%str1 = internal constant [4 x sbyte] c"int\00", section "llvm.metadata"
1363</pre>
1364
1365</div>
1366
1367<!-- ======================================================================= -->
1368<div class="doc_subsubsection">
1369 <a name="ccxx_basic_unsigned_int">unsigned int</a>
1370</div>
1371
1372<div class="doc_text">
1373
1374<pre>
1375%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1376 uint 36,
1377 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1378 sbyte* getelementptr ([13 x sbyte]* %str1, int 0, int 0),
1379 { }* null,
1380 int 0,
1381 uint 32,
1382 uint 32,
1383 uint 0,
1384 uint 7 }, section "llvm.metadata"
1385%str1 = internal constant [13 x sbyte] c"unsigned int\00", section "llvm.metadata"
1386</pre>
1387
1388</div>
1389
1390<!-- ======================================================================= -->
1391<div class="doc_subsubsection">
1392 <a name="ccxx_basic_long_long">long long</a>
1393</div>
1394
1395<div class="doc_text">
1396
1397<pre>
1398%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1399 uint 36,
1400 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1401 sbyte* getelementptr ([14 x sbyte]* %str1, int 0, int 0),
1402 { }* null,
1403 int 0,
1404 uint 64,
1405 uint 64,
1406 uint 0,
1407 uint 5 }, section "llvm.metadata"
1408%str1 = internal constant [14 x sbyte] c"long long int\00", section "llvm.metadata"
1409</pre>
1410
1411</div>
1412
1413<!-- ======================================================================= -->
1414<div class="doc_subsubsection">
1415 <a name="ccxx_basic_unsigned_long_long">unsigned long long</a>
1416</div>
1417
1418<div class="doc_text">
1419
1420<pre>
1421%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1422 uint 36,
1423 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1424 sbyte* getelementptr ([23 x sbyte]* %str1, int 0, int 0),
1425 { }* null,
1426 int 0,
1427 uint 64,
1428 uint 64,
1429 uint 0,
1430 uint 7 }, section "llvm.metadata"
1431%str1 = internal constant [23 x sbyte] c"long long unsigned int\00", section "llvm.metadata"
1432</pre>
1433
1434</div>
1435
1436<!-- ======================================================================= -->
1437<div class="doc_subsubsection">
1438 <a name="ccxx_basic_float">float</a>
1439</div>
1440
1441<div class="doc_text">
1442
1443<pre>
1444%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1445 uint 36,
1446 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1447 sbyte* getelementptr ([6 x sbyte]* %str1, int 0, int 0),
1448 { }* null,
1449 int 0,
1450 uint 32,
1451 uint 32,
1452 uint 0,
1453 uint 4 }, section "llvm.metadata"
1454%str1 = internal constant [6 x sbyte] c"float\00", section "llvm.metadata"
1455</pre>
1456
1457</div>
1458
1459<!-- ======================================================================= -->
1460<div class="doc_subsubsection">
1461 <a name="ccxx_basic_double">double</a>
1462</div>
1463
1464<div class="doc_text">
1465
1466<pre>
1467%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1468 uint 36,
1469 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1470 sbyte* getelementptr ([7 x sbyte]* %str1, int 0, int 0),
1471 { }* null,
1472 int 0,
1473 uint 64,
1474 uint 64,
1475 uint 0,
1476 uint 4 }, section "llvm.metadata"
1477%str1 = internal constant [7 x sbyte] c"double\00", section "llvm.metadata"
1478</pre>
1479
1480</div>
1481
1482<!-- ======================================================================= -->
1483<div class="doc_subsection">
1484 <a name="ccxx_derived_types">C/C++ derived types</a>
1485</div>
1486
1487<div class="doc_text">
1488
1489<p>Given the following as an example of C/C++ derived type;</p>
1490
1491<pre>
1492typedef const int *IntPtr;
1493</pre>
1494
1495<p>a C/C++ front-end would generate the following descriptors;</p>
1496
1497<pre>
1498;;
1499;; Define the typedef "IntPtr".
1500;;
1501%<a href="#format_derived_type">llvm.dbg.derivedtype1</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
1502 uint 22,
1503 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1504 sbyte* getelementptr ([7 x sbyte]* %str1, int 0, int 0),
1505 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1506 int 1,
1507 uint 0,
1508 uint 0,
1509 uint 0,
1510 { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype2</a> to { }*) }, section "llvm.metadata"
1511%str1 = internal constant [7 x sbyte] c"IntPtr\00", section "llvm.metadata"
1512
1513;;
1514;; Define the pointer type.
1515;;
1516%<a href="#format_derived_type">llvm.dbg.derivedtype2</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
1517 uint 15,
1518 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Jim Laskey4d9b10b2006-03-14 18:50:50 +0000[diff] [blame]1519 sbyte* null,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1520 { }* null,
1521 int 0,
1522 uint 32,
1523 uint 32,
1524 uint 0,
1525 { }* 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]1526
1527;;
1528;; Define the const type.
1529;;
1530%<a href="#format_derived_type">llvm.dbg.derivedtype3</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
1531 uint 38,
1532 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Jim Laskey4d9b10b2006-03-14 18:50:50 +0000[diff] [blame]1533 sbyte* null,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1534 { }* null,
1535 int 0,
1536 uint 0,
1537 uint 0,
1538 uint 0,
1539 { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype1</a> to { }*) }, section "llvm.metadata"
1540
1541;;
1542;; Define the int type.
1543;;
1544%<a href="#format_basic_type">llvm.dbg.basictype1</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1545 uint 36,
1546 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
Jim Laskey4d9b10b2006-03-14 18:50:50 +0000[diff] [blame]1547 sbyte* getelementptr ([4 x sbyte]* %str2, int 0, int 0),
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1548 { }* null,
1549 int 0,
1550 uint 32,
1551 uint 32,
1552 uint 0,
1553 uint 5 }, section "llvm.metadata"
Jim Laskey4d9b10b2006-03-14 18:50:50 +0000[diff] [blame]1554%str2 = internal constant [4 x sbyte] c"int\00", section "llvm.metadata"
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1555</pre>
1556
1557</div>
1558
1559<!-- ======================================================================= -->
1560<div class="doc_subsection">
1561 <a name="ccxx_composite_types">C/C++ struct/union types</a>
1562</div>
1563
1564<div class="doc_text">
1565
1566<p>Given the following as an example of C/C++ struct type;</p>
1567
1568<pre>
1569struct Color {
1570 unsigned Red;
1571 unsigned Green;
1572 unsigned Blue;
1573};
1574</pre>
1575
1576<p>a C/C++ front-end would generate the following descriptors;</p>
1577
1578<pre>
1579;;
1580;; Define basic type for unsigned int.
1581;;
1582%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
1583 uint 36,
1584 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1585 sbyte* getelementptr ([13 x sbyte]* %str1, int 0, int 0),
1586 { }* null,
1587 int 0,
1588 uint 32,
1589 uint 32,
1590 uint 0,
1591 uint 7 }, section "llvm.metadata"
1592%str1 = internal constant [13 x sbyte] c"unsigned int\00", section "llvm.metadata"
1593
1594;;
1595;; Define composite type for struct Color.
1596;;
1597%<a href="#format_composite_type">llvm.dbg.compositetype</a> = internal constant %<a href="#format_composite_type">llvm.dbg.compositetype.type</a> {
1598 uint 19,
1599 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1600 sbyte* getelementptr ([6 x sbyte]* %str2, int 0, int 0),
1601 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1602 int 1,
1603 uint 96,
1604 uint 32,
1605 uint 0,
Jim Laskeyf8a01a92006-06-15 20:51:43 +0000[diff] [blame^]1606 { }* null,
1607 bool false,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1608 { }* cast ([3 x { }*]* %llvm.dbg.array to { }*) }, section "llvm.metadata"
1609%str2 = internal constant [6 x sbyte] c"Color\00", section "llvm.metadata"
1610
1611;;
1612;; Define the Red field.
1613;;
1614%<a href="#format_derived_type">llvm.dbg.derivedtype1</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
1615 uint 13,
1616 { }* null,
1617 sbyte* getelementptr ([4 x sbyte]* %str3, int 0, int 0),
1618 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1619 int 2,
1620 uint 32,
1621 uint 32,
1622 uint 0,
1623 { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata"
1624%str3 = internal constant [4 x sbyte] c"Red\00", section "llvm.metadata"
1625
1626;;
1627;; Define the Green field.
1628;;
1629%<a href="#format_derived_type">llvm.dbg.derivedtype2</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
1630 uint 13,
1631 { }* null,
1632 sbyte* getelementptr ([6 x sbyte]* %str4, int 0, int 0),
1633 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1634 int 3,
1635 uint 32,
1636 uint 32,
1637 uint 32,
1638 { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata"
1639%str4 = internal constant [6 x sbyte] c"Green\00", section "llvm.metadata"
1640
1641;;
1642;; Define the Blue field.
1643;;
1644%<a href="#format_derived_type">llvm.dbg.derivedtype3</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
1645 uint 13,
1646 { }* null,
1647 sbyte* getelementptr ([5 x sbyte]* %str5, int 0, int 0),
1648 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1649 int 4,
1650 uint 32,
1651 uint 32,
1652 uint 64,
1653 { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata"
1654%str5 = internal constant [5 x sbyte] c"Blue\00", section "llvm.metadata"
1655
1656;;
1657;; Define the array of fields used by the composite type Color.
1658;;
1659%llvm.dbg.array = internal constant [3 x { }*] [
1660 { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype1</a> to { }*),
1661 { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype2</a> to { }*),
1662 { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype3</a> to { }*) ], section "llvm.metadata"
1663</pre>
1664
1665</div>
1666
1667<!-- ======================================================================= -->
1668<div class="doc_subsection">
1669 <a name="ccxx_enumeration_types">C/C++ enumeration types</a>
1670</div>
1671
1672<div class="doc_text">
1673
1674<p>Given the following as an example of C/C++ enumeration type;</p>
1675
1676<pre>
1677enum Trees {
1678 Spruce = 100,
1679 Oak = 200,
1680 Maple = 300
1681};
1682</pre>
1683
1684<p>a C/C++ front-end would generate the following descriptors;</p>
1685
1686<pre>
1687;;
1688;; Define composite type for enum Trees
1689;;
1690%<a href="#format_composite_type">llvm.dbg.compositetype</a> = internal constant %<a href="#format_composite_type">llvm.dbg.compositetype.type</a> {
1691 uint 4,
1692 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1693 sbyte* getelementptr ([6 x sbyte]* %str1, int 0, int 0),
1694 { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
1695 int 1,
1696 uint 32,
1697 uint 32,
1698 uint 0,
1699 { }* null,
Jim Laskeyf8a01a92006-06-15 20:51:43 +0000[diff] [blame^]1700 bool false,
Jim Laskeycec12a52006-03-14 18:08:46 +0000[diff] [blame]1701 { }* cast ([3 x { }*]* %llvm.dbg.array to { }*) }, section "llvm.metadata"
1702%str1 = internal constant [6 x sbyte] c"Trees\00", section "llvm.metadata"
1703
1704;;
1705;; Define Spruce enumerator.
1706;;
1707%<a href="#format_enumeration">llvm.dbg.enumerator1</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> {
1708 uint 40,
1709 sbyte* getelementptr ([7 x sbyte]* %str2, int 0, int 0),
1710 int 100 }, section "llvm.metadata"
1711%str2 = internal constant [7 x sbyte] c"Spruce\00", section "llvm.metadata"
1712
1713;;
1714;; Define Oak enumerator.
1715;;
1716%<a href="#format_enumeration">llvm.dbg.enumerator2</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> {
1717 uint 40,
1718 sbyte* getelementptr ([4 x sbyte]* %str3, int 0, int 0),
1719 int 200 }, section "llvm.metadata"
1720%str3 = internal constant [4 x sbyte] c"Oak\00", section "llvm.metadata"
1721
1722;;
1723;; Define Maple enumerator.
1724;;
1725%<a href="#format_enumeration">llvm.dbg.enumerator3</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> {
1726 uint 40,
1727 sbyte* getelementptr ([6 x sbyte]* %str4, int 0, int 0),
1728 int 300 }, section "llvm.metadata"
1729%str4 = internal constant [6 x sbyte] c"Maple\00", section "llvm.metadata"
1730
1731;;
1732;; Define the array of enumerators used by composite type Trees.
1733;;
1734%llvm.dbg.array = internal constant [3 x { }*] [
1735 { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator1</a> to { }*),
1736 { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator2</a> to { }*),
1737 { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator3</a> to { }*) ], section "llvm.metadata"
1738</pre>
1739
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1751 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
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