1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
6 <title>Source Level Debugging with LLVM</title>
7 <link rel="stylesheet" href="llvm.css" type="text/css">
11 <h1>Source Level Debugging with LLVM</h1>
13 <table class="layout" style="width:100%">
17 <li><a href="#introduction">Introduction</a>
19 <li><a href="#phil">Philosophy behind LLVM debugging information</a></li>
20 <li><a href="#consumers">Debug information consumers</a></li>
21 <li><a href="#debugopt">Debugging optimized code</a></li>
23 <li><a href="#format">Debugging information format</a>
25 <li><a href="#debug_info_descriptors">Debug information descriptors</a>
27 <li><a href="#format_compile_units">Compile unit descriptors</a></li>
28 <li><a href="#format_files">File 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>
31 <li><a href="#format_blocks">Block descriptors</a></li>
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>
37 <li><a href="#format_variables">Local variables</a></li>
39 <li><a href="#format_common_intrinsics">Debugger intrinsic functions</a>
41 <li><a href="#format_common_declare">llvm.dbg.declare</a></li>
42 <li><a href="#format_common_value">llvm.dbg.value</a></li>
45 <li><a href="#format_common_lifetime">Object lifetimes and scoping</a></li>
46 <li><a href="#ccxx_frontend">C/C++ front-end specific debug information</a>
48 <li><a href="#ccxx_compile_units">C/C++ source file information</a></li>
49 <li><a href="#ccxx_global_variable">C/C++ global variable information</a></li>
50 <li><a href="#ccxx_subprogram">C/C++ function information</a></li>
51 <li><a href="#ccxx_basic_types">C/C++ basic types</a></li>
52 <li><a href="#ccxx_derived_types">C/C++ derived types</a></li>
53 <li><a href="#ccxx_composite_types">C/C++ struct/union types</a></li>
54 <li><a href="#ccxx_enumeration_types">C/C++ enumeration types</a></li>
59 <img src="img/venusflytrap.jpg" alt="A leafy and green bug eater" width="247"
64 <div class="doc_author">
65 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
66 and <a href="mailto:jlaskey@mac.com">Jim Laskey</a></p>
70 <!-- *********************************************************************** -->
71 <h2><a name="introduction">Introduction</a></h2>
72 <!-- *********************************************************************** -->
76 <p>This document is the central repository for all information pertaining to
77 debug information in LLVM. It describes the <a href="#format">actual format
78 that the LLVM debug information</a> takes, which is useful for those
79 interested in creating front-ends or dealing directly with the information.
80 Further, this document provides specific examples of what debug information
81 for C/C++ looks like.</p>
83 <!-- ======================================================================= -->
85 <a name="phil">Philosophy behind LLVM debugging information</a>
90 <p>The idea of the LLVM debugging information is to capture how the important
91 pieces of the source-language's Abstract Syntax Tree map onto LLVM code.
92 Several design aspects have shaped the solution that appears here. The
93 important ones are:</p>
96 <li>Debugging information should have very little impact on the rest of the
97 compiler. No transformations, analyses, or code generators should need to
98 be modified because of debugging information.</li>
100 <li>LLVM optimizations should interact in <a href="#debugopt">well-defined and
101 easily described ways</a> with the debugging information.</li>
103 <li>Because LLVM is designed to support arbitrary programming languages,
104 LLVM-to-LLVM tools should not need to know anything about the semantics of
105 the source-level-language.</li>
107 <li>Source-level languages are often <b>widely</b> different from one another.
108 LLVM should not put any restrictions of the flavor of the source-language,
109 and the debugging information should work with any language.</li>
111 <li>With code generator support, it should be possible to use an LLVM compiler
112 to compile a program to native machine code and standard debugging
113 formats. This allows compatibility with traditional machine-code level
114 debuggers, like GDB or DBX.</li>
117 <p>The approach used by the LLVM implementation is to use a small set
118 of <a href="#format_common_intrinsics">intrinsic functions</a> to define a
119 mapping between LLVM program objects and the source-level objects. The
120 description of the source-level program is maintained in LLVM metadata
121 in an <a href="#ccxx_frontend">implementation-defined format</a>
122 (the C/C++ front-end currently uses working draft 7 of
123 the <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3
126 <p>When a program is being debugged, a debugger interacts with the user and
127 turns the stored debug information into source-language specific information.
128 As such, a debugger must be aware of the source-language, and is thus tied to
129 a specific language or family of languages.</p>
133 <!-- ======================================================================= -->
135 <a name="consumers">Debug information consumers</a>
140 <p>The role of debug information is to provide meta information normally
141 stripped away during the compilation process. This meta information provides
142 an LLVM user a relationship between generated code and the original program
145 <p>Currently, debug information is consumed by DwarfDebug to produce dwarf
146 information used by the gdb debugger. Other targets could use the same
147 information to produce stabs or other debug forms.</p>
149 <p>It would also be reasonable to use debug information to feed profiling tools
150 for analysis of generated code, or, tools for reconstructing the original
151 source from generated code.</p>
153 <p>TODO - expound a bit more.</p>
157 <!-- ======================================================================= -->
159 <a name="debugopt">Debugging optimized code</a>
164 <p>An extremely high priority of LLVM debugging information is to make it
165 interact well with optimizations and analysis. In particular, the LLVM debug
166 information provides the following guarantees:</p>
169 <li>LLVM debug information <b>always provides information to accurately read
170 the source-level state of the program</b>, regardless of which LLVM
171 optimizations have been run, and without any modification to the
172 optimizations themselves. However, some optimizations may impact the
173 ability to modify the current state of the program with a debugger, such
174 as setting program variables, or calling functions that have been
177 <li>As desired, LLVM optimizations can be upgraded to be aware of the LLVM
178 debugging information, allowing them to update the debugging information
179 as they perform aggressive optimizations. This means that, with effort,
180 the LLVM optimizers could optimize debug code just as well as non-debug
183 <li>LLVM debug information does not prevent optimizations from
184 happening (for example inlining, basic block reordering/merging/cleanup,
185 tail duplication, etc).</li>
187 <li>LLVM debug information is automatically optimized along with the rest of
188 the program, using existing facilities. For example, duplicate
189 information is automatically merged by the linker, and unused information
190 is automatically removed.</li>
193 <p>Basically, the debug information allows you to compile a program with
194 "<tt>-O0 -g</tt>" and get full debug information, allowing you to arbitrarily
195 modify the program as it executes from a debugger. Compiling a program with
196 "<tt>-O3 -g</tt>" gives you full debug information that is always available
197 and accurate for reading (e.g., you get accurate stack traces despite tail
198 call elimination and inlining), but you might lose the ability to modify the
199 program and call functions where were optimized out of the program, or
200 inlined away completely.</p>
202 <p><a href="TestingGuide.html#quicktestsuite">LLVM test suite</a> provides a
203 framework to test optimizer's handling of debugging information. It can be
206 <div class="doc_code">
208 % cd llvm/projects/test-suite/MultiSource/Benchmarks # or some other level
213 <p>This will test impact of debugging information on optimization passes. If
214 debugging information influences optimization passes then it will be reported
215 as a failure. See <a href="TestingGuide.html">TestingGuide</a> for more
216 information on LLVM test infrastructure and how to run various tests.</p>
222 <!-- *********************************************************************** -->
224 <a name="format">Debugging information format</a>
226 <!-- *********************************************************************** -->
230 <p>LLVM debugging information has been carefully designed to make it possible
231 for the optimizer to optimize the program and debugging information without
232 necessarily having to know anything about debugging information. In
233 particular, the use of metadata avoids duplicated debugging information from
234 the beginning, and the global dead code elimination pass automatically
235 deletes debugging information for a function if it decides to delete the
238 <p>To do this, most of the debugging information (descriptors for types,
239 variables, functions, source files, etc) is inserted by the language
240 front-end in the form of LLVM metadata. </p>
242 <p>Debug information is designed to be agnostic about the target debugger and
243 debugging information representation (e.g. DWARF/Stabs/etc). It uses a
244 generic pass to decode the information that represents variables, types,
245 functions, namespaces, etc: this allows for arbitrary source-language
246 semantics and type-systems to be used, as long as there is a module
247 written for the target debugger to interpret the information. </p>
249 <p>To provide basic functionality, the LLVM debugger does have to make some
250 assumptions about the source-level language being debugged, though it keeps
251 these to a minimum. The only common features that the LLVM debugger assumes
252 exist are <a href="#format_files">source files</a>,
253 and <a href="#format_global_variables">program objects</a>. These abstract
254 objects are used by a debugger to form stack traces, show information about
255 local variables, etc.</p>
257 <p>This section of the documentation first describes the representation aspects
258 common to any source-language. The <a href="#ccxx_frontend">next section</a>
259 describes the data layout conventions used by the C and C++ front-ends.</p>
261 <!-- ======================================================================= -->
263 <a name="debug_info_descriptors">Debug information descriptors</a>
268 <p>In consideration of the complexity and volume of debug information, LLVM
269 provides a specification for well formed debug descriptors. </p>
271 <p>Consumers of LLVM debug information expect the descriptors for program
272 objects to start in a canonical format, but the descriptors can include
273 additional information appended at the end that is source-language
274 specific. All LLVM debugging information is versioned, allowing backwards
275 compatibility in the case that the core structures need to change in some
276 way. Also, all debugging information objects start with a tag to indicate
277 what type of object it is. The source-language is allowed to define its own
278 objects, by using unreserved tag numbers. We recommend using with tags in
279 the range 0x1000 through 0x2000 (there is a defined enum DW_TAG_user_base =
282 <p>The fields of debug descriptors used internally by LLVM
283 are restricted to only the simple data types <tt>i32</tt>, <tt>i1</tt>,
284 <tt>float</tt>, <tt>double</tt>, <tt>mdstring</tt> and <tt>mdnode</tt>. </p>
286 <div class="doc_code">
295 <p><a name="LLVMDebugVersion">The first field of a descriptor is always an
296 <tt>i32</tt> containing a tag value identifying the content of the
297 descriptor. The remaining fields are specific to the descriptor. The values
298 of tags are loosely bound to the tag values of DWARF information entries.
299 However, that does not restrict the use of the information supplied to DWARF
300 targets. To facilitate versioning of debug information, the tag is augmented
301 with the current debug version (LLVMDebugVersion = 8 << 16 or
302 0x80000 or 524288.)</a></p>
304 <p>The details of the various descriptors follow.</p>
306 <!-- ======================================================================= -->
308 <a name="format_compile_units">Compile unit descriptors</a>
313 <div class="doc_code">
316 i32, ;; Tag = 17 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
317 ;; (DW_TAG_compile_unit)
318 i32, ;; Unused field.
319 i32, ;; DWARF language identifier (ex. DW_LANG_C89)
320 metadata, ;; Source file name
321 metadata, ;; Source file directory (includes trailing slash)
322 metadata ;; Producer (ex. "4.0.1 LLVM (LLVM research group)")
323 i1, ;; True if this is a main compile unit.
324 i1, ;; True if this is optimized.
326 i32 ;; Runtime version
327 metadata ;; List of enums types
328 metadata ;; List of retained types
329 metadata ;; List of subprograms
330 metadata ;; List of global variables
335 <p>These descriptors contain a source language ID for the file (we use the DWARF
336 3.0 ID numbers, such as <tt>DW_LANG_C89</tt>, <tt>DW_LANG_C_plus_plus</tt>,
337 <tt>DW_LANG_Cobol74</tt>, etc), three strings describing the filename,
338 working directory of the compiler, and an identifier string for the compiler
339 that produced it.</p>
341 <p>Compile unit descriptors provide the root context for objects declared in a
342 specific compilation unit. File descriptors are defined using this context.
343 These descriptors are collected by a named metadata
344 <tt>!llvm.dbg.cu</tt>. Compile unit descriptor keeps track of subprograms,
345 global variables and type information.
349 <!-- ======================================================================= -->
351 <a name="format_files">File descriptors</a>
356 <div class="doc_code">
359 i32, ;; Tag = 41 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
360 ;; (DW_TAG_file_type)
361 metadata, ;; Source file name
362 metadata, ;; Source file directory (includes trailing slash)
368 <p>These descriptors contain information for a file. Global variables and top
369 level functions would be defined using this context.k File descriptors also
370 provide context for source line correspondence. </p>
372 <p>Each input file is encoded as a separate file descriptor in LLVM debugging
373 information output. </p>
377 <!-- ======================================================================= -->
379 <a name="format_global_variables">Global variable descriptors</a>
384 <div class="doc_code">
387 i32, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
389 i32, ;; Unused field.
390 metadata, ;; Reference to context descriptor
392 metadata, ;; Display name (fully qualified C++ name)
393 metadata, ;; MIPS linkage name (for C++)
394 metadata, ;; Reference to file where defined
395 i32, ;; Line number where defined
396 metadata, ;; Reference to type descriptor
397 i1, ;; True if the global is local to compile unit (static)
398 i1, ;; True if the global is defined in the compile unit (not extern)
399 {}* ;; Reference to the global variable
404 <p>These descriptors provide debug information about globals variables. The
405 provide details such as name, type and where the variable is defined. All
406 global variables are collected by named metadata <tt>!llvm.dbg.gv</tt>.</p>
410 <!-- ======================================================================= -->
412 <a name="format_subprograms">Subprogram descriptors</a>
417 <div class="doc_code">
420 i32, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
421 ;; (DW_TAG_subprogram)
422 i32, ;; Unused field.
423 metadata, ;; Reference to context descriptor
425 metadata, ;; Display name (fully qualified C++ name)
426 metadata, ;; MIPS linkage name (for C++)
427 metadata, ;; Reference to file where defined
428 i32, ;; Line number where defined
429 metadata, ;; Reference to type descriptor
430 i1, ;; True if the global is local to compile unit (static)
431 i1, ;; True if the global is defined in the compile unit (not extern)
432 i32, ;; Virtuality, e.g. dwarf::DW_VIRTUALITY__virtual
433 i32, ;; Index into a virtual function
434 metadata, ;; indicates which base type contains the vtable pointer for the
438 Function *,;; Pointer to LLVM function
439 metadata, ;; Lists function template parameters
440 metadata ;; Function declaration descriptor
441 metadata ;; List of function variables
446 <p>These descriptors provide debug information about functions, methods and
447 subprograms. They provide details such as name, return types and the source
448 location where the subprogram is defined.
449 All subprogram descriptors are collected by a named metadata
450 <tt>!llvm.dbg.sp</tt>.
455 <!-- ======================================================================= -->
457 <a name="format_blocks">Block descriptors</a>
462 <div class="doc_code">
465 i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
466 metadata,;; Reference to context descriptor
468 i32, ;; Column number
469 metadata,;; Reference to source file
470 i32 ;; Unique ID to identify blocks from a template function
475 <p>This descriptor provides debug information about nested blocks within a
476 subprogram. The line number and column numbers are used to dinstinguish
477 two lexical blocks at same depth. </p>
479 <div class="doc_code">
482 i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
483 metadata ;; Reference to the scope we're annotating with a file change
484 metadata,;; Reference to the file the scope is enclosed in.
489 <p>This descriptor provides a wrapper around a lexical scope to handle file
490 changes in the middle of a lexical block.</p>
494 <!-- ======================================================================= -->
496 <a name="format_basic_type">Basic type descriptors</a>
501 <div class="doc_code">
504 i32, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
505 ;; (DW_TAG_base_type)
506 metadata, ;; Reference to context
507 metadata, ;; Name (may be "" for anonymous types)
508 metadata, ;; Reference to file where defined (may be NULL)
509 i32, ;; Line number where defined (may be 0)
511 i64, ;; Alignment in bits
512 i64, ;; Offset in bits
514 i32 ;; DWARF type encoding
519 <p>These descriptors define primitive types used in the code. Example int, bool
520 and float. The context provides the scope of the type, which is usually the
521 top level. Since basic types are not usually user defined the context
522 and line number can be left as NULL and 0. The size, alignment and offset
523 are expressed in bits and can be 64 bit values. The alignment is used to
524 round the offset when embedded in a
525 <a href="#format_composite_type">composite type</a> (example to keep float
526 doubles on 64 bit boundaries.) The offset is the bit offset if embedded in
527 a <a href="#format_composite_type">composite type</a>.</p>
529 <p>The type encoding provides the details of the type. The values are typically
530 one of the following:</p>
532 <div class="doc_code">
538 DW_ATE_signed_char = 6
540 DW_ATE_unsigned_char = 8
546 <!-- ======================================================================= -->
548 <a name="format_derived_type">Derived type descriptors</a>
553 <div class="doc_code">
556 i32, ;; Tag (see below)
557 metadata, ;; Reference to context
558 metadata, ;; Name (may be "" for anonymous types)
559 metadata, ;; Reference to file where defined (may be NULL)
560 i32, ;; Line number where defined (may be 0)
562 i64, ;; Alignment in bits
563 i64, ;; Offset in bits
564 metadata, ;; Reference to type derived from
565 metadata, ;; (optional) Name of the Objective C property assoicated with
566 ;; Objective-C an ivar
567 metadata, ;; (optional) Name of the Objective C property getter selector.
568 metadata, ;; (optional) Name of the Objective C property setter selector.
569 i32 ;; (optional) Objective C property attributes.
574 <p>These descriptors are used to define types derived from other types. The
575 value of the tag varies depending on the meaning. The following are possible
578 <div class="doc_code">
580 DW_TAG_formal_parameter = 5
582 DW_TAG_pointer_type = 15
583 DW_TAG_reference_type = 16
585 DW_TAG_const_type = 38
586 DW_TAG_volatile_type = 53
587 DW_TAG_restrict_type = 55
591 <p><tt>DW_TAG_member</tt> is used to define a member of
592 a <a href="#format_composite_type">composite type</a>
593 or <a href="#format_subprograms">subprogram</a>. The type of the member is
594 the <a href="#format_derived_type">derived
595 type</a>. <tt>DW_TAG_formal_parameter</tt> is used to define a member which
596 is a formal argument of a subprogram.</p>
598 <p><tt>DW_TAG_typedef</tt> is used to provide a name for the derived type.</p>
600 <p><tt>DW_TAG_pointer_type</tt>,<tt>DW_TAG_reference_type</tt>,
601 <tt>DW_TAG_const_type</tt>, <tt>DW_TAG_volatile_type</tt>
602 and <tt>DW_TAG_restrict_type</tt> are used to qualify
603 the <a href="#format_derived_type">derived type</a>. </p>
605 <p><a href="#format_derived_type">Derived type</a> location can be determined
606 from the context and line number. The size, alignment and offset are
607 expressed in bits and can be 64 bit values. The alignment is used to round
608 the offset when embedded in a <a href="#format_composite_type">composite
609 type</a> (example to keep float doubles on 64 bit boundaries.) The offset is
610 the bit offset if embedded in a <a href="#format_composite_type">composite
613 <p>Note that the <tt>void *</tt> type is expressed as a type derived from NULL.
618 <!-- ======================================================================= -->
620 <a name="format_composite_type">Composite type descriptors</a>
625 <div class="doc_code">
628 i32, ;; Tag (see below)
629 metadata, ;; Reference to context
630 metadata, ;; Name (may be "" for anonymous types)
631 metadata, ;; Reference to file where defined (may be NULL)
632 i32, ;; Line number where defined (may be 0)
634 i64, ;; Alignment in bits
635 i64, ;; Offset in bits
637 metadata, ;; Reference to type derived from
638 metadata, ;; Reference to array of member descriptors
639 i32 ;; Runtime languages
644 <p>These descriptors are used to define types that are composed of 0 or more
645 elements. The value of the tag varies depending on the meaning. The following
646 are possible tag values:</p>
648 <div class="doc_code">
650 DW_TAG_array_type = 1
651 DW_TAG_enumeration_type = 4
652 DW_TAG_structure_type = 19
653 DW_TAG_union_type = 23
654 DW_TAG_vector_type = 259
655 DW_TAG_subroutine_type = 21
656 DW_TAG_inheritance = 28
660 <p>The vector flag indicates that an array type is a native packed vector.</p>
662 <p>The members of array types (tag = <tt>DW_TAG_array_type</tt>) or vector types
663 (tag = <tt>DW_TAG_vector_type</tt>) are <a href="#format_subrange">subrange
664 descriptors</a>, each representing the range of subscripts at that level of
667 <p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are
668 <a href="#format_enumeration">enumerator descriptors</a>, each representing
669 the definition of enumeration value for the set. All enumeration type
670 descriptors are collected by named metadata <tt>!llvm.dbg.enum</tt>.</p>
672 <p>The members of structure (tag = <tt>DW_TAG_structure_type</tt>) or union (tag
673 = <tt>DW_TAG_union_type</tt>) types are any one of
674 the <a href="#format_basic_type">basic</a>,
675 <a href="#format_derived_type">derived</a>
676 or <a href="#format_composite_type">composite</a> type descriptors, each
677 representing a field member of the structure or union.</p>
679 <p>For C++ classes (tag = <tt>DW_TAG_structure_type</tt>), member descriptors
680 provide information about base classes, static members and member
681 functions. If a member is a <a href="#format_derived_type">derived type
682 descriptor</a> and has a tag of <tt>DW_TAG_inheritance</tt>, then the type
683 represents a base class. If the member of is
684 a <a href="#format_global_variables">global variable descriptor</a> then it
685 represents a static member. And, if the member is
686 a <a href="#format_subprograms">subprogram descriptor</a> then it represents
687 a member function. For static members and member
688 functions, <tt>getName()</tt> returns the members link or the C++ mangled
689 name. <tt>getDisplayName()</tt> the simplied version of the name.</p>
691 <p>The first member of subroutine (tag = <tt>DW_TAG_subroutine_type</tt>) type
692 elements is the return type for the subroutine. The remaining elements are
693 the formal arguments to the subroutine.</p>
695 <p><a href="#format_composite_type">Composite type</a> location can be
696 determined from the context and line number. The size, alignment and
697 offset are expressed in bits and can be 64 bit values. The alignment is used
698 to round the offset when embedded in
699 a <a href="#format_composite_type">composite type</a> (as an example, to keep
700 float doubles on 64 bit boundaries.) The offset is the bit offset if embedded
701 in a <a href="#format_composite_type">composite type</a>.</p>
705 <!-- ======================================================================= -->
707 <a name="format_subrange">Subrange descriptors</a>
712 <div class="doc_code">
715 i32, ;; Tag = 33 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subrange_type)
722 <p>These descriptors are used to define ranges of array subscripts for an array
723 <a href="#format_composite_type">composite type</a>. The low value defines
724 the lower bounds typically zero for C/C++. The high value is the upper
725 bounds. Values are 64 bit. High - low + 1 is the size of the array. If low
726 > high the array bounds are not included in generated debugging information.
731 <!-- ======================================================================= -->
733 <a name="format_enumeration">Enumerator descriptors</a>
738 <div class="doc_code">
741 i32, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
742 ;; (DW_TAG_enumerator)
749 <p>These descriptors are used to define members of an
750 enumeration <a href="#format_composite_type">composite type</a>, it
751 associates the name to the value.</p>
755 <!-- ======================================================================= -->
757 <a name="format_variables">Local variables</a>
762 <div class="doc_code">
765 i32, ;; Tag (see below)
768 metadata, ;; Reference to file where defined
769 i32, ;; 24 bit - Line number where defined
770 ;; 8 bit - Argument number. 1 indicates 1st argument.
771 metadata, ;; Type descriptor
773 metadata ;; (optional) Reference to inline location
778 <p>These descriptors are used to define variables local to a sub program. The
779 value of the tag depends on the usage of the variable:</p>
781 <div class="doc_code">
783 DW_TAG_auto_variable = 256
784 DW_TAG_arg_variable = 257
785 DW_TAG_return_variable = 258
789 <p>An auto variable is any variable declared in the body of the function. An
790 argument variable is any variable that appears as a formal argument to the
791 function. A return variable is used to track the result of a function and
792 has no source correspondent.</p>
794 <p>The context is either the subprogram or block where the variable is defined.
795 Name the source variable name. Context and line indicate where the
796 variable was defined. Type descriptor defines the declared type of the
803 <!-- ======================================================================= -->
805 <a name="format_common_intrinsics">Debugger intrinsic functions</a>
810 <p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to
811 provide debug information at various points in generated code.</p>
813 <!-- ======================================================================= -->
815 <a name="format_common_declare">llvm.dbg.declare</a>
820 void %<a href="#format_common_declare">llvm.dbg.declare</a>(metadata, metadata)
823 <p>This intrinsic provides information about a local element (ex. variable.) The
824 first argument is metadata holding alloca for the variable. The
825 second argument is metadata containing description of the variable. </p>
828 <!-- ======================================================================= -->
830 <a name="format_common_value">llvm.dbg.value</a>
835 void %<a href="#format_common_value">llvm.dbg.value</a>(metadata, i64, metadata)
838 <p>This intrinsic provides information when a user source variable is set to a
839 new value. The first argument is the new value (wrapped as metadata). The
840 second argument is the offset in the user source variable where the new value
841 is written. The third argument is metadata containing description of the
842 user source variable. </p>
847 <!-- ======================================================================= -->
849 <a name="format_common_lifetime">Object lifetimes and scoping</a>
853 <p>In many languages, the local variables in functions can have their lifetimes
854 or scopes limited to a subset of a function. In the C family of languages,
855 for example, variables are only live (readable and writable) within the
856 source block that they are defined in. In functional languages, values are
857 only readable after they have been defined. Though this is a very obvious
858 concept, it is non-trivial to model in LLVM, because it has no notion of
859 scoping in this sense, and does not want to be tied to a language's scoping
862 <p>In order to handle this, the LLVM debug format uses the metadata attached to
863 llvm instructions to encode line number and scoping information. Consider
864 the following C fragment, for example:</p>
866 <div class="doc_code">
880 <p>Compiled to LLVM, this function would be represented like this:</p>
882 <div class="doc_code">
884 define void @foo() nounwind ssp {
886 %X = alloca i32, align 4 ; <i32*> [#uses=4]
887 %Y = alloca i32, align 4 ; <i32*> [#uses=4]
888 %Z = alloca i32, align 4 ; <i32*> [#uses=3]
889 %0 = bitcast i32* %X to {}* ; <{}*> [#uses=1]
890 call void @llvm.dbg.declare(metadata !{i32 * %X}, metadata !0), !dbg !7
891 store i32 21, i32* %X, !dbg !8
892 %1 = bitcast i32* %Y to {}* ; <{}*> [#uses=1]
893 call void @llvm.dbg.declare(metadata !{i32 * %Y}, metadata !9), !dbg !10
894 store i32 22, i32* %Y, !dbg !11
895 %2 = bitcast i32* %Z to {}* ; <{}*> [#uses=1]
896 call void @llvm.dbg.declare(metadata !{i32 * %Z}, metadata !12), !dbg !14
897 store i32 23, i32* %Z, !dbg !15
898 %tmp = load i32* %X, !dbg !16 ; <i32> [#uses=1]
899 %tmp1 = load i32* %Y, !dbg !16 ; <i32> [#uses=1]
900 %add = add nsw i32 %tmp, %tmp1, !dbg !16 ; <i32> [#uses=1]
901 store i32 %add, i32* %Z, !dbg !16
902 %tmp2 = load i32* %Y, !dbg !17 ; <i32> [#uses=1]
903 store i32 %tmp2, i32* %X, !dbg !17
907 declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
909 !0 = metadata !{i32 459008, metadata !1, metadata !"X",
910 metadata !3, i32 2, metadata !6}; [ DW_TAG_auto_variable ]
911 !1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
912 !2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo", metadata !"foo",
913 metadata !"foo", metadata !3, i32 1, metadata !4,
914 i1 false, i1 true}; [DW_TAG_subprogram ]
915 !3 = metadata !{i32 458769, i32 0, i32 12, metadata !"foo.c",
916 metadata !"/private/tmp", metadata !"clang 1.1", i1 true,
917 i1 false, metadata !"", i32 0}; [DW_TAG_compile_unit ]
918 !4 = metadata !{i32 458773, metadata !3, metadata !"", null, i32 0, i64 0, i64 0,
919 i64 0, i32 0, null, metadata !5, i32 0}; [DW_TAG_subroutine_type ]
920 !5 = metadata !{null}
921 !6 = metadata !{i32 458788, metadata !3, metadata !"int", metadata !3, i32 0,
922 i64 32, i64 32, i64 0, i32 0, i32 5}; [DW_TAG_base_type ]
923 !7 = metadata !{i32 2, i32 7, metadata !1, null}
924 !8 = metadata !{i32 2, i32 3, metadata !1, null}
925 !9 = metadata !{i32 459008, metadata !1, metadata !"Y", metadata !3, i32 3,
926 metadata !6}; [ DW_TAG_auto_variable ]
927 !10 = metadata !{i32 3, i32 7, metadata !1, null}
928 !11 = metadata !{i32 3, i32 3, metadata !1, null}
929 !12 = metadata !{i32 459008, metadata !13, metadata !"Z", metadata !3, i32 5,
930 metadata !6}; [ DW_TAG_auto_variable ]
931 !13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
932 !14 = metadata !{i32 5, i32 9, metadata !13, null}
933 !15 = metadata !{i32 5, i32 5, metadata !13, null}
934 !16 = metadata !{i32 6, i32 5, metadata !13, null}
935 !17 = metadata !{i32 8, i32 3, metadata !1, null}
936 !18 = metadata !{i32 9, i32 1, metadata !2, null}
940 <p>This example illustrates a few important details about LLVM debugging
941 information. In particular, it shows how the <tt>llvm.dbg.declare</tt>
942 intrinsic and location information, which are attached to an instruction,
943 are applied together to allow a debugger to analyze the relationship between
944 statements, variable definitions, and the code used to implement the
947 <div class="doc_code">
949 call void @llvm.dbg.declare(metadata, metadata !0), !dbg !7
953 <p>The first intrinsic
954 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
955 encodes debugging information for the variable <tt>X</tt>. The metadata
956 <tt>!dbg !7</tt> attached to the intrinsic provides scope information for the
957 variable <tt>X</tt>.</p>
959 <div class="doc_code">
961 !7 = metadata !{i32 2, i32 7, metadata !1, null}
962 !1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
963 !2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo",
964 metadata !"foo", metadata !"foo", metadata !3, i32 1,
965 metadata !4, i1 false, i1 true}; [DW_TAG_subprogram ]
969 <p>Here <tt>!7</tt> is metadata providing location information. It has four
970 fields: line number, column number, scope, and original scope. The original
971 scope represents inline location if this instruction is inlined inside a
972 caller, and is null otherwise. In this example, scope is encoded by
973 <tt>!1</tt>. <tt>!1</tt> represents a lexical block inside the scope
974 <tt>!2</tt>, where <tt>!2</tt> is a
975 <a href="#format_subprograms">subprogram descriptor</a>. This way the
976 location information attached to the intrinsics indicates that the
977 variable <tt>X</tt> is declared at line number 2 at a function level scope in
978 function <tt>foo</tt>.</p>
980 <p>Now lets take another example.</p>
982 <div class="doc_code">
984 call void @llvm.dbg.declare(metadata, metadata !12), !dbg !14
988 <p>The second intrinsic
989 <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
990 encodes debugging information for variable <tt>Z</tt>. The metadata
991 <tt>!dbg !14</tt> attached to the intrinsic provides scope information for
992 the variable <tt>Z</tt>.</p>
994 <div class="doc_code">
996 !13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
997 !14 = metadata !{i32 5, i32 9, metadata !13, null}
1001 <p>Here <tt>!14</tt> indicates that <tt>Z</tt> is declared at line number 5 and
1002 column number 9 inside of lexical scope <tt>!13</tt>. The lexical scope
1003 itself resides inside of lexical scope <tt>!1</tt> described above.</p>
1005 <p>The scope information attached with each instruction provides a
1006 straightforward way to find instructions covered by a scope.</p>
1012 <!-- *********************************************************************** -->
1014 <a name="ccxx_frontend">C/C++ front-end specific debug information</a>
1016 <!-- *********************************************************************** -->
1020 <p>The C and C++ front-ends represent information about the program in a format
1021 that is effectively identical
1022 to <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3.0</a> in
1023 terms of information content. This allows code generators to trivially
1024 support native debuggers by generating standard dwarf information, and
1025 contains enough information for non-dwarf targets to translate it as
1028 <p>This section describes the forms used to represent C and C++ programs. Other
1029 languages could pattern themselves after this (which itself is tuned to
1030 representing programs in the same way that DWARF 3 does), or they could
1031 choose to provide completely different forms if they don't fit into the DWARF
1032 model. As support for debugging information gets added to the various LLVM
1033 source-language front-ends, the information used should be documented
1036 <p>The following sections provide examples of various C/C++ constructs and the
1037 debug information that would best describe those constructs.</p>
1039 <!-- ======================================================================= -->
1041 <a name="ccxx_compile_units">C/C++ source file information</a>
1046 <p>Given the source files <tt>MySource.cpp</tt> and <tt>MyHeader.h</tt> located
1047 in the directory <tt>/Users/mine/sources</tt>, the following code:</p>
1049 <div class="doc_code">
1051 #include "MyHeader.h"
1053 int main(int argc, char *argv[]) {
1059 <p>a C/C++ front-end would generate the following descriptors:</p>
1061 <div class="doc_code">
1065 ;; Define the compile unit for the main source file "/Users/mine/sources/MySource.cpp".
1070 i32 4, ;; Language Id
1071 metadata !"MySource.cpp",
1072 metadata !"/Users/mine/sources",
1073 metadata !"4.2.1 (Based on Apple Inc. build 5649) (LLVM build 00)",
1074 i1 true, ;; Main Compile Unit
1075 i1 false, ;; Optimized compile unit
1076 metadata !"", ;; Compiler flags
1077 i32 0} ;; Runtime version
1080 ;; Define the file for the file "/Users/mine/sources/MySource.cpp".
1084 metadata !"MySource.cpp",
1085 metadata !"/Users/mine/sources",
1086 metadata !2 ;; Compile unit
1090 ;; Define the file for the file "/Users/mine/sources/Myheader.h"
1094 metadata !"Myheader.h"
1095 metadata !"/Users/mine/sources",
1096 metadata !2 ;; Compile unit
1103 <p>llvm::Instruction provides easy access to metadata attached with an
1104 instruction. One can extract line number information encoded in LLVM IR
1105 using <tt>Instruction::getMetadata()</tt> and
1106 <tt>DILocation::getLineNumber()</tt>.
1108 if (MDNode *N = I->getMetadata("dbg")) { // Here I is an LLVM instruction
1109 DILocation Loc(N); // DILocation is in DebugInfo.h
1110 unsigned Line = Loc.getLineNumber();
1111 StringRef File = Loc.getFilename();
1112 StringRef Dir = Loc.getDirectory();
1117 <!-- ======================================================================= -->
1119 <a name="ccxx_global_variable">C/C++ global variable information</a>
1124 <p>Given an integer global variable declared as follows:</p>
1126 <div class="doc_code">
1132 <p>a C/C++ front-end would generate the following descriptors:</p>
1134 <div class="doc_code">
1137 ;; Define the global itself.
1139 %MyGlobal = global int 100
1142 ;; List of debug info of globals
1144 !llvm.dbg.gv = !{!0}
1147 ;; Define the global variable descriptor. Note the reference to the global
1148 ;; variable anchor and the global variable itself.
1153 metadata !1, ;; Context
1154 metadata !"MyGlobal", ;; Name
1155 metadata !"MyGlobal", ;; Display Name
1156 metadata !"MyGlobal", ;; Linkage Name
1157 metadata !3, ;; Compile Unit
1158 i32 1, ;; Line Number
1159 metadata !4, ;; Type
1160 i1 false, ;; Is a local variable
1161 i1 true, ;; Is this a definition
1162 i32* @MyGlobal ;; The global variable
1166 ;; Define the basic type of 32 bit signed integer. Note that since int is an
1167 ;; intrinsic type the source file is NULL and line 0.
1171 metadata !1, ;; Context
1172 metadata !"int", ;; Name
1173 metadata !1, ;; File
1174 i32 0, ;; Line number
1175 i64 32, ;; Size in Bits
1176 i64 32, ;; Align in Bits
1177 i64 0, ;; Offset in Bits
1187 <!-- ======================================================================= -->
1189 <a name="ccxx_subprogram">C/C++ function information</a>
1194 <p>Given a function declared as follows:</p>
1196 <div class="doc_code">
1198 int main(int argc, char *argv[]) {
1204 <p>a C/C++ front-end would generate the following descriptors:</p>
1206 <div class="doc_code">
1209 ;; Define the anchor for subprograms. Note that the second field of the
1210 ;; anchor is 46, which is the same as the tag for subprograms
1211 ;; (46 = DW_TAG_subprogram.)
1216 metadata !1, ;; Context
1217 metadata !"main", ;; Name
1218 metadata !"main", ;; Display name
1219 metadata !"main", ;; Linkage name
1220 metadata !1, ;; File
1221 i32 1, ;; Line number
1222 metadata !4, ;; Type
1223 i1 false, ;; Is local
1224 i1 true, ;; Is definition
1225 i32 0, ;; Virtuality attribute, e.g. pure virtual function
1226 i32 0, ;; Index into virtual table for C++ methods
1227 i32 0, ;; Type that holds virtual table.
1229 i1 false, ;; True if this function is optimized
1230 Function *, ;; Pointer to llvm::Function
1231 null ;; Function template parameters
1234 ;; Define the subprogram itself.
1236 define i32 @main(i32 %argc, i8** %argv) {
1244 <!-- ======================================================================= -->
1246 <a name="ccxx_basic_types">C/C++ basic types</a>
1251 <p>The following are the basic type descriptors for C/C++ core types:</p>
1253 <!-- ======================================================================= -->
1255 <a name="ccxx_basic_type_bool">bool</a>
1260 <div class="doc_code">
1264 metadata !1, ;; Context
1265 metadata !"bool", ;; Name
1266 metadata !1, ;; File
1267 i32 0, ;; Line number
1268 i64 8, ;; Size in Bits
1269 i64 8, ;; Align in Bits
1270 i64 0, ;; Offset in Bits
1279 <!-- ======================================================================= -->
1281 <a name="ccxx_basic_char">char</a>
1286 <div class="doc_code">
1290 metadata !1, ;; Context
1291 metadata !"char", ;; Name
1292 metadata !1, ;; File
1293 i32 0, ;; Line number
1294 i64 8, ;; Size in Bits
1295 i64 8, ;; Align in Bits
1296 i64 0, ;; Offset in Bits
1305 <!-- ======================================================================= -->
1307 <a name="ccxx_basic_unsigned_char">unsigned char</a>
1312 <div class="doc_code">
1316 metadata !1, ;; Context
1317 metadata !"unsigned char",
1318 metadata !1, ;; File
1319 i32 0, ;; Line number
1320 i64 8, ;; Size in Bits
1321 i64 8, ;; Align in Bits
1322 i64 0, ;; Offset in Bits
1331 <!-- ======================================================================= -->
1333 <a name="ccxx_basic_short">short</a>
1338 <div class="doc_code">
1342 metadata !1, ;; Context
1343 metadata !"short int",
1344 metadata !1, ;; File
1345 i32 0, ;; Line number
1346 i64 16, ;; Size in Bits
1347 i64 16, ;; Align in Bits
1348 i64 0, ;; Offset in Bits
1357 <!-- ======================================================================= -->
1359 <a name="ccxx_basic_unsigned_short">unsigned short</a>
1364 <div class="doc_code">
1368 metadata !1, ;; Context
1369 metadata !"short unsigned int",
1370 metadata !1, ;; File
1371 i32 0, ;; Line number
1372 i64 16, ;; Size in Bits
1373 i64 16, ;; Align in Bits
1374 i64 0, ;; Offset in Bits
1383 <!-- ======================================================================= -->
1385 <a name="ccxx_basic_int">int</a>
1390 <div class="doc_code">
1394 metadata !1, ;; Context
1395 metadata !"int", ;; Name
1396 metadata !1, ;; File
1397 i32 0, ;; Line number
1398 i64 32, ;; Size in Bits
1399 i64 32, ;; Align in Bits
1400 i64 0, ;; Offset in Bits
1408 <!-- ======================================================================= -->
1410 <a name="ccxx_basic_unsigned_int">unsigned int</a>
1415 <div class="doc_code">
1419 metadata !1, ;; Context
1420 metadata !"unsigned int",
1421 metadata !1, ;; File
1422 i32 0, ;; Line number
1423 i64 32, ;; Size in Bits
1424 i64 32, ;; Align in Bits
1425 i64 0, ;; Offset in Bits
1434 <!-- ======================================================================= -->
1436 <a name="ccxx_basic_long_long">long long</a>
1441 <div class="doc_code">
1445 metadata !1, ;; Context
1446 metadata !"long long int",
1447 metadata !1, ;; File
1448 i32 0, ;; Line number
1449 i64 64, ;; Size in Bits
1450 i64 64, ;; Align in Bits
1451 i64 0, ;; Offset in Bits
1460 <!-- ======================================================================= -->
1462 <a name="ccxx_basic_unsigned_long_long">unsigned long long</a>
1467 <div class="doc_code">
1471 metadata !1, ;; Context
1472 metadata !"long long unsigned int",
1473 metadata !1, ;; File
1474 i32 0, ;; Line number
1475 i64 64, ;; Size in Bits
1476 i64 64, ;; Align in Bits
1477 i64 0, ;; Offset in Bits
1486 <!-- ======================================================================= -->
1488 <a name="ccxx_basic_float">float</a>
1493 <div class="doc_code">
1497 metadata !1, ;; Context
1499 metadata !1, ;; File
1500 i32 0, ;; Line number
1501 i64 32, ;; Size in Bits
1502 i64 32, ;; Align in Bits
1503 i64 0, ;; Offset in Bits
1512 <!-- ======================================================================= -->
1514 <a name="ccxx_basic_double">double</a>
1519 <div class="doc_code">
1523 metadata !1, ;; Context
1524 metadata !"double",;; Name
1525 metadata !1, ;; File
1526 i32 0, ;; Line number
1527 i64 64, ;; Size in Bits
1528 i64 64, ;; Align in Bits
1529 i64 0, ;; Offset in Bits
1540 <!-- ======================================================================= -->
1542 <a name="ccxx_derived_types">C/C++ derived types</a>
1547 <p>Given the following as an example of C/C++ derived type:</p>
1549 <div class="doc_code">
1551 typedef const int *IntPtr;
1555 <p>a C/C++ front-end would generate the following descriptors:</p>
1557 <div class="doc_code">
1560 ;; Define the typedef "IntPtr".
1564 metadata !1, ;; Context
1565 metadata !"IntPtr", ;; Name
1566 metadata !3, ;; File
1567 i32 0, ;; Line number
1568 i64 0, ;; Size in bits
1569 i64 0, ;; Align in bits
1570 i64 0, ;; Offset in bits
1572 metadata !4 ;; Derived From type
1576 ;; Define the pointer type.
1580 metadata !1, ;; Context
1581 metadata !"", ;; Name
1582 metadata !1, ;; File
1583 i32 0, ;; Line number
1584 i64 64, ;; Size in bits
1585 i64 64, ;; Align in bits
1586 i64 0, ;; Offset in bits
1588 metadata !5 ;; Derived From type
1591 ;; Define the const type.
1595 metadata !1, ;; Context
1596 metadata !"", ;; Name
1597 metadata !1, ;; File
1598 i32 0, ;; Line number
1599 i64 32, ;; Size in bits
1600 i64 32, ;; Align in bits
1601 i64 0, ;; Offset in bits
1603 metadata !6 ;; Derived From type
1606 ;; Define the int type.
1610 metadata !1, ;; Context
1611 metadata !"int", ;; Name
1612 metadata !1, ;; File
1613 i32 0, ;; Line number
1614 i64 32, ;; Size in bits
1615 i64 32, ;; Align in bits
1616 i64 0, ;; Offset in bits
1625 <!-- ======================================================================= -->
1627 <a name="ccxx_composite_types">C/C++ struct/union types</a>
1632 <p>Given the following as an example of C/C++ struct type:</p>
1634 <div class="doc_code">
1644 <p>a C/C++ front-end would generate the following descriptors:</p>
1646 <div class="doc_code">
1649 ;; Define basic type for unsigned int.
1653 metadata !1, ;; Context
1654 metadata !"unsigned int",
1655 metadata !1, ;; File
1656 i32 0, ;; Line number
1657 i64 32, ;; Size in Bits
1658 i64 32, ;; Align in Bits
1659 i64 0, ;; Offset in Bits
1664 ;; Define composite type for struct Color.
1668 metadata !1, ;; Context
1669 metadata !"Color", ;; Name
1670 metadata !1, ;; Compile unit
1671 i32 1, ;; Line number
1672 i64 96, ;; Size in bits
1673 i64 32, ;; Align in bits
1674 i64 0, ;; Offset in bits
1676 null, ;; Derived From
1677 metadata !3, ;; Elements
1678 i32 0 ;; Runtime Language
1682 ;; Define the Red field.
1686 metadata !1, ;; Context
1687 metadata !"Red", ;; Name
1688 metadata !1, ;; File
1689 i32 2, ;; Line number
1690 i64 32, ;; Size in bits
1691 i64 32, ;; Align in bits
1692 i64 0, ;; Offset in bits
1694 metadata !5 ;; Derived From type
1698 ;; Define the Green field.
1702 metadata !1, ;; Context
1703 metadata !"Green", ;; Name
1704 metadata !1, ;; File
1705 i32 3, ;; Line number
1706 i64 32, ;; Size in bits
1707 i64 32, ;; Align in bits
1708 i64 32, ;; Offset in bits
1710 metadata !5 ;; Derived From type
1714 ;; Define the Blue field.
1718 metadata !1, ;; Context
1719 metadata !"Blue", ;; Name
1720 metadata !1, ;; File
1721 i32 4, ;; Line number
1722 i64 32, ;; Size in bits
1723 i64 32, ;; Align in bits
1724 i64 64, ;; Offset in bits
1726 metadata !5 ;; Derived From type
1730 ;; Define the array of fields used by the composite type Color.
1732 !3 = metadata !{metadata !4, metadata !6, metadata !7}
1738 <!-- ======================================================================= -->
1740 <a name="ccxx_enumeration_types">C/C++ enumeration types</a>
1745 <p>Given the following as an example of C/C++ enumeration type:</p>
1747 <div class="doc_code">
1757 <p>a C/C++ front-end would generate the following descriptors:</p>
1759 <div class="doc_code">
1762 ;; Define composite type for enum Trees
1766 metadata !1, ;; Context
1767 metadata !"Trees", ;; Name
1768 metadata !1, ;; File
1769 i32 1, ;; Line number
1770 i64 32, ;; Size in bits
1771 i64 32, ;; Align in bits
1772 i64 0, ;; Offset in bits
1774 null, ;; Derived From type
1775 metadata !3, ;; Elements
1776 i32 0 ;; Runtime language
1780 ;; Define the array of enumerators used by composite type Trees.
1782 !3 = metadata !{metadata !4, metadata !5, metadata !6}
1785 ;; Define Spruce enumerator.
1787 !4 = metadata !{i32 524328, metadata !"Spruce", i64 100}
1790 ;; Define Oak enumerator.
1792 !5 = metadata !{i32 524328, metadata !"Oak", i64 200}
1795 ;; Define Maple enumerator.
1797 !6 = metadata !{i32 524328, metadata !"Maple", i64 300}
1806 <!-- *********************************************************************** -->
1810 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
1811 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
1812 <a href="http://validator.w3.org/check/referer"><img
1813 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
1815 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
1816 <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
1817 Last modified: $Date$