Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" |
| 2 | "http://www.w3.org/TR/html4/strict.dtd"> |
| 3 | <html> |
| 4 | <head> |
| 5 | <title>Source Level Debugging with LLVM</title> |
| 6 | <link rel="stylesheet" href="llvm.css" type="text/css"> |
| 7 | </head> |
| 8 | <body> |
| 9 | |
| 10 | <div class="doc_title">Source Level Debugging with LLVM</div> |
| 11 | |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 12 | <table class="layout" style="width:100%"> |
| 13 | <tr class="layout"> |
| 14 | <td class="left"> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 15 | <ul> |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 16 | <li><a href="#introduction">Introduction</a> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 17 | <ol> |
| 18 | <li><a href="#phil">Philosophy behind LLVM debugging information</a></li> |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 19 | <li><a href="#consumers">Debug information consumers</a></li> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 20 | <li><a href="#debugopt">Debugging optimized code</a></li> |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 21 | </ol></li> |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 22 | <li><a href="#format">Debugging information format</a> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 23 | <ol> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 24 | <li><a href="#debug_info_descriptors">Debug information descriptors</a> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 25 | <ul> |
Jim Laskey | cec12a5 | 2006-03-14 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 Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 30 | <li><a href="#format_blocks">Block descriptors</a></li> |
Jim Laskey | cec12a5 | 2006-03-14 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 Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 36 | <li><a href="#format_variables">Local variables</a></li> |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 37 | </ul></li> |
Jim Laskey | cec12a5 | 2006-03-14 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 Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 48 | </ol></li> |
| 49 | <li><a href="#ccxx_frontend">C/C++ front-end specific debug information</a> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 50 | <ol> |
Jim Laskey | cec12a5 | 2006-03-14 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 Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 58 | </ol></li> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 59 | </ul> |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 60 | </td> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 61 | <td class="right"> |
Misha Brukman | e849a1a | 2004-05-12 21:26:16 +0000 | [diff] [blame] | 62 | <img src="img/venusflytrap.jpg" alt="A leafy and green bug eater" width="247" |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 63 | height="369"> |
| 64 | </td> |
Reid Spencer | d3f876c | 2004-11-01 08:19:36 +0000 | [diff] [blame] | 65 | </tr></table> |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 66 | |
Chris Lattner | 7911ce2 | 2004-05-23 21:07:27 +0000 | [diff] [blame] | 67 | <div class="doc_author"> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 68 | <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a> |
Jim Laskey | c760a92 | 2007-03-14 19:32:21 +0000 | [diff] [blame^] | 69 | and <a href="mailto:jlaskey@mac.com">Jim Laskey</a></p> |
Chris Lattner | 7911ce2 | 2004-05-23 21:07:27 +0000 | [diff] [blame] | 70 | </div> |
| 71 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 72 | |
| 73 | <!-- *********************************************************************** --> |
Misha Brukman | 94218a7 | 2004-12-09 20:27:37 +0000 | [diff] [blame] | 74 | <div class="doc_section"><a name="introduction">Introduction</a></div> |
| 75 | <!-- *********************************************************************** --> |
Chris Lattner | bdfb339 | 2004-01-05 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 Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 80 | debug information in LLVM. It describes the <a href="#format">actual format |
| 81 | that the LLVM debug information</a> takes, which is useful for those interested |
| 82 | in creating front-ends or dealing directly with the information. Further, this |
| 83 | document provides specifc examples of what debug information for C/C++.</p> |
Chris Lattner | bdfb339 | 2004-01-05 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 Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 94 | <p>The idea of the LLVM debugging information is to capture how the important |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 95 | pieces of the source-language's Abstract Syntax Tree map onto LLVM code. |
| 96 | Several design aspects have shaped the solution that appears here. The |
| 97 | important ones are:</p> |
| 98 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 99 | <ul> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 100 | <li>Debugging information should have very little impact on the rest of the |
| 101 | compiler. No transformations, analyses, or code generators should need to be |
| 102 | modified because of debugging information.</li> |
| 103 | |
| 104 | <li>LLVM optimizations should interact in <a href="#debugopt">well-defined and |
| 105 | easily described ways</a> with the debugging information.</li> |
| 106 | |
| 107 | <li>Because LLVM is designed to support arbitrary programming languages, |
| 108 | LLVM-to-LLVM tools should not need to know anything about the semantics of the |
| 109 | source-level-language.</li> |
| 110 | |
| 111 | <li>Source-level languages are often <b>widely</b> different from one another. |
| 112 | LLVM should not put any restrictions of the flavor of the source-language, and |
| 113 | the 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 Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 116 | to compile a program to native machine code and standard debugging formats. |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 117 | This allows compatibility with traditional machine-code level debuggers, like |
| 118 | GDB or DBX.</li> |
| 119 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 120 | </ul> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 121 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 122 | <p>The approach used by the LLVM implementation is to use a small set of <a |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 123 | href="#format_common_intrinsics">intrinsic functions</a> to define a mapping |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 124 | between LLVM program objects and the source-level objects. The description of |
| 125 | the source-level program is maintained in LLVM global variables in an <a |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 126 | href="#ccxx_frontend">implementation-defined format</a> (the C/C++ front-end |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 127 | currently uses working draft 7 of the <a |
| 128 | href="http://www.eagercon.com/dwarf/dwarf3std.htm">Dwarf 3 standard</a>).</p> |
| 129 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 130 | <p>When a program is being debugged, a debugger interacts with the user and |
| 131 | turns the stored debug information into source-language specific information. |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 132 | As such, a debugger must be aware of the source-language, and is thus tied to |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 133 | a specific language of family of languages.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 134 | |
| 135 | </div> |
| 136 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 137 | <!-- ======================================================================= --> |
| 138 | <div class="doc_subsection"> |
Jim Laskey | 383e009 | 2006-03-23 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 |
| 144 | stripped away during the compilation process. This meta information provides an |
| 145 | llvm user a relationship between generated code and the original program source |
| 146 | code.</p> |
| 147 | |
| 148 | <p>Currently, debug information is consumed by the DwarfWriter to produce dwarf |
| 149 | information used by the gdb debugger. Other targets could use the same |
| 150 | information to produce stabs or other debug forms.</p> |
| 151 | |
| 152 | <p>It would also be reasonable to use debug information to feed profiling tools |
| 153 | for analysis of generated code, or, tools for reconstructing the original source |
| 154 | from generated code.</p> |
| 155 | |
| 156 | <p>TODO - expound a bit more.</p> |
| 157 | |
| 158 | </div> |
| 159 | |
| 160 | <!-- ======================================================================= --> |
| 161 | <div class="doc_subsection"> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 162 | <a name="debugopt">Debugging optimized code</a> |
| 163 | </div> |
| 164 | |
| 165 | <div class="doc_text"> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 166 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 167 | <p>An extremely high priority of LLVM debugging information is to make it |
| 168 | interact well with optimizations and analysis. In particular, the LLVM debug |
| 169 | information provides the following guarantees:</p> |
| 170 | |
| 171 | <ul> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 172 | |
| 173 | <li>LLVM debug information <b>always provides information to accurately read the |
| 174 | source-level state of the program</b>, regardless of which LLVM optimizations |
| 175 | have been run, and without any modification to the optimizations themselves. |
| 176 | However, some optimizations may impact the ability to modify the current state |
| 177 | of the program with a debugger, such as setting program variables, or calling |
| 178 | function that have been deleted.</li> |
| 179 | |
| 180 | <li>LLVM optimizations gracefully interact with debugging information. If they |
| 181 | are not aware of debug information, they are automatically disabled as necessary |
| 182 | in the cases that would invalidate the debug info. This retains the LLVM |
| 183 | features making it easy to write new transformations.</li> |
| 184 | |
| 185 | <li>As desired, LLVM optimizations can be upgraded to be aware of the LLVM |
| 186 | debugging information, allowing them to update the debugging information as they |
| 187 | perform aggressive optimizations. This means that, with effort, the LLVM |
| 188 | optimizers 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 |
| 191 | happening (for example inlining, basic block reordering/merging/cleanup, tail |
| 192 | duplication, etc), further reducing the amount of the compiler that eventually |
| 193 | is "aware" of debugging information.</li> |
| 194 | |
| 195 | <li>LLVM debug information is automatically optimized along with the rest of the |
| 196 | program, using existing facilities. For example, duplicate information is |
| 197 | automatically merged by the linker, and unused information is automatically |
| 198 | removed.</li> |
| 199 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 200 | </ul> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 201 | |
Misha Brukman | 8287373 | 2004-05-12 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 Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 204 | modify the program as it executes from a debugger. Compiling a program with |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 205 | "<tt>-O3 -g</tt>" gives you full debug information that is always available and |
| 206 | accurate for reading (e.g., you get accurate stack traces despite tail call |
| 207 | elimination and inlining), but you might lose the ability to modify the program |
| 208 | and call functions where were optimized out of the program, or inlined away |
| 209 | completely.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 210 | |
| 211 | </div> |
| 212 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 213 | <!-- *********************************************************************** --> |
| 214 | <div class="doc_section"> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 215 | <a name="format">Debugging information format</a> |
Chris Lattner | bdfb339 | 2004-01-05 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 |
| 222 | for the optimizer to optimize the program and debugging information without |
| 223 | necessarily having to know anything about debugging information. In particular, |
| 224 | the global constant merging pass automatically eliminates duplicated debugging |
| 225 | information (often caused by header files), the global dead code elimination |
| 226 | pass automatically deletes debugging information for a function if it decides to |
| 227 | delete 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, |
| 231 | variables, functions, source files, etc) is inserted by the language front-end |
| 232 | in the form of LLVM global variables. These LLVM global variables are no |
| 233 | different from any other global variables, except that they have a web of LLVM |
| 234 | intrinsic functions that point to them. If the last references to a particular |
| 235 | piece of debugging information are deleted (for example, by the |
| 236 | <tt>-globaldce</tt> pass), the extraneous debug information will automatically |
| 237 | become dead and be removed by the optimizer.</p> |
| 238 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 239 | <p>Debug information is designed to be agnostic about the target debugger and |
| 240 | debugging information representation (e.g. DWARF/Stabs/etc). It uses a generic |
| 241 | machine debug information pass to decode the information that represents |
| 242 | variables, types, functions, namespaces, etc: this allows for arbitrary |
| 243 | source-language semantics and type-systems to be used, as long as there is a |
| 244 | module written for the target debugger to interpret the information. In |
| 245 | addition, debug global variables are declared in the <tt>"llvm.metadata"</tt> |
| 246 | section. All values declared in this section are stripped away after target |
| 247 | debug information is constructed and before the program object is emitted.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 248 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 249 | <p>To provide basic functionality, the LLVM debugger does have to make some |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 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 |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 252 | exist are <a href="#format_compile_units">source files</a>, and <a |
| 253 | href="#format_global_variables">program objects</a>. These abstract objects are |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 254 | used by a debugger to form stack traces, show information about local |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 255 | variables, etc.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 256 | |
| 257 | <p>This section of the documentation first describes the representation aspects |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 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> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 260 | |
| 261 | </div> |
| 262 | |
| 263 | <!-- ======================================================================= --> |
| 264 | <div class="doc_subsection"> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 265 | <a name="debug_info_descriptors">Debug information descriptors</a> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 266 | </div> |
| 267 | |
| 268 | <div class="doc_text"> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 269 | <p>In consideration of the complexity and volume of debug information, LLVM |
| 270 | provides a specification for well formed debug global variables. The constant |
| 271 | value of each of these globals is one of a limited set of structures, known as |
| 272 | debug descriptors.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 273 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 274 | <p>Consumers of LLVM debug information expect the descriptors for program |
| 275 | objects to start in a canonical format, but the descriptors can include |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 276 | additional information appended at the end that is source-language specific. All |
| 277 | LLVM debugging information is versioned, allowing backwards compatibility in the |
| 278 | case that the core structures need to change in some way. Also, all debugging |
| 279 | information objects start with a tag to indicate what type of object it is. The |
| 280 | source-language is allowed to define its own objects, by using unreserved tag |
| 281 | numbers. We recommend using with tags in the range 0x1000 thru 0x2000 (there is |
| 282 | a defined enum DW_TAG_user_base = 0x1000.)</p> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 283 | |
Jim Laskey | 44c3b9f | 2007-01-26 21:22:28 +0000 | [diff] [blame] | 284 | <p>The fields of debug descriptors used internally by LLVM (MachineModuleInfo) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 285 | are 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 |
| 288 | cast to <tt> { }* </tt> expression; typically references to other field |
| 289 | descriptors, arrays of descriptors or global variables.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 290 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 291 | <pre> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 292 | %llvm.dbg.object.type = type { |
| 293 | uint, ;; A tag |
| 294 | ... |
| 295 | } |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 296 | </pre> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 297 | |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 298 | <p><a name="LLVMDebugVersion">The first field of a descriptor is always an |
| 299 | <tt>uint</tt> containing a tag value identifying the content of the descriptor. |
| 300 | The remaining fields are specific to the descriptor. The values of tags are |
| 301 | loosely bound to the tag values of Dwarf information entries. However, that |
| 302 | does not restrict the use of the information supplied to Dwarf targets. To |
| 303 | facilitate versioning of debug information, the tag is augmented with the |
Jim Laskey | 76a015e | 2006-06-16 13:45:38 +0000 | [diff] [blame] | 304 | current debug version (LLVMDebugVersion = 4 << 16 or 0x40000 or 262144.)</a></p> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 305 | |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 306 | <p>The details of the various descriptors follow.</p> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 307 | |
| 308 | </div> |
| 309 | |
| 310 | <!-- ======================================================================= --> |
| 311 | <div class="doc_subsubsection"> |
| 312 | <a name="format_anchors">Anchor descriptors</a> |
| 313 | </div> |
| 314 | |
| 315 | <div class="doc_text"> |
| 316 | |
| 317 | <pre> |
| 318 | %<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 319 | uint, ;; Tag = 0 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 320 | uint ;; Tag of descriptors grouped by the anchor |
| 321 | } |
| 322 | </pre> |
| 323 | |
| 324 | <p>One important aspect of the LLVM debug representation is that it allows the |
| 325 | LLVM debugger to efficiently index all of the global objects without having the |
| 326 | scan the program. To do this, all of the global objects use "anchor" |
| 327 | descriptors with designated names. All of the global objects of a particular |
| 328 | type (e.g., compile units) contain a pointer to the anchor. This pointer allows |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 329 | a debugger to use def-use chains to find all global objects of that type.</p> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 330 | |
| 331 | <p>The following names are recognized as anchors by LLVM:</p> |
| 332 | |
| 333 | <pre> |
| 334 | %<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 |
| 335 | %<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 |
| 336 | %<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 |
| 337 | </pre> |
| 338 | |
| 339 | <p>Using anchors in this way (where the compile unit descriptor points to the |
| 340 | anchors, as opposed to having a list of compile unit descriptors) allows for the |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 341 | standard dead global elimination and merging passes to automatically remove |
| 342 | unused debugging information. If the globals were kept track of through lists, |
| 343 | there would always be an object pointing to the descriptors, thus would never be |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 344 | deleted.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 345 | |
| 346 | </div> |
| 347 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 348 | <!-- ======================================================================= --> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 349 | <div class="doc_subsubsection"> |
| 350 | <a name="format_compile_units">Compile unit descriptors</a> |
| 351 | </div> |
| 352 | |
| 353 | <div class="doc_text"> |
| 354 | |
| 355 | <pre> |
| 356 | %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = type { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 357 | uint, ;; Tag = 17 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_compile_unit) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 358 | { }*, ;; 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 Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 359 | uint, ;; Dwarf language identifier (ex. DW_LANG_C89) |
| 360 | sbyte*, ;; Source file name |
| 361 | sbyte*, ;; Source file directory (includes trailing slash) |
| 362 | sbyte* ;; Producer (ex. "4.0.1 LLVM (LLVM research group)") |
| 363 | } |
| 364 | </pre> |
| 365 | |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 366 | <p>These descriptors contain a source language ID for the file (we use the Dwarf |
| 367 | 3.0 ID numbers, such as <tt>DW_LANG_C89</tt>, <tt>DW_LANG_C_plus_plus</tt>, |
| 368 | <tt>DW_LANG_Cobol74</tt>, etc), three strings describing the filename, working |
| 369 | directory of the compiler, and an identifier string for the compiler that |
| 370 | produced it.</p> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 371 | |
| 372 | <p> Compile unit descriptors provide the root context for objects declared in a |
| 373 | specific source file. Global variables and top level functions would be defined |
| 374 | using this context. Compile unit descriptors also provide context for source |
| 375 | line correspondence.</p> |
| 376 | |
| 377 | </div> |
| 378 | |
| 379 | <!-- ======================================================================= --> |
| 380 | <div class="doc_subsubsection"> |
| 381 | <a name="format_global_variables">Global variable descriptors</a> |
| 382 | </div> |
| 383 | |
| 384 | <div class="doc_text"> |
| 385 | |
| 386 | <pre> |
| 387 | %<a href="#format_global_variables">llvm.dbg.global_variable.type</a> = type { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 388 | uint, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_variable) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 389 | { }*, ;; 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 Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 390 | { }*, ;; Reference to context descriptor |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 391 | sbyte*, ;; Name |
Jim Laskey | fe79381 | 2006-11-30 14:36:22 +0000 | [diff] [blame] | 392 | sbyte*, ;; Display name (fully qualified C++ name) |
| 393 | sbyte*, ;; MIPS linkage name (for C++) |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 394 | { }*, ;; Reference to compile unit where defined |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 395 | uint, ;; Line number where defined |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 396 | { }*, ;; Reference to type descriptor |
| 397 | bool, ;; True if the global is local to compile unit (static) |
| 398 | bool, ;; True if the global is defined in the compile unit (not extern) |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 399 | { }* ;; Reference to the global variable |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 400 | } |
| 401 | </pre> |
| 402 | |
| 403 | <p>These descriptors provide debug information about globals variables. The |
| 404 | provide details such as name, type and where the variable is defined.</p> |
| 405 | |
| 406 | </div> |
| 407 | |
| 408 | <!-- ======================================================================= --> |
| 409 | <div class="doc_subsubsection"> |
| 410 | <a name="format_subprograms">Subprogram descriptors</a> |
| 411 | </div> |
| 412 | |
| 413 | <div class="doc_text"> |
| 414 | |
| 415 | <pre> |
| 416 | %<a href="#format_subprograms">llvm.dbg.subprogram.type</a> = type { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 417 | uint, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subprogram) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 418 | { }*, ;; Subprogram anchor = cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_subprograms">llvm.dbg.subprograms</a> to { }*), |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 419 | { }*, ;; Reference to context descriptor |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 420 | sbyte*, ;; Name |
Jim Laskey | fe79381 | 2006-11-30 14:36:22 +0000 | [diff] [blame] | 421 | sbyte*, ;; Display name (fully qualified C++ name) |
| 422 | sbyte*, ;; MIPS linkage name (for C++) |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 423 | { }*, ;; Reference to compile unit where defined |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 424 | uint, ;; Line number where defined |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 425 | { }*, ;; Reference to type descriptor |
| 426 | bool, ;; True if the global is local to compile unit (static) |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 427 | bool ;; True if the global is defined in the compile unit (not extern) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 428 | } |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 429 | </pre> |
| 430 | |
| 431 | <p>These descriptors provide debug information about functions, methods and |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 432 | subprograms. They provide details such as name, return types and the source |
| 433 | location where the subprogram is defined.</p> |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 434 | |
| 435 | </div> |
| 436 | <!-- ======================================================================= --> |
| 437 | <div class="doc_subsubsection"> |
| 438 | <a name="format_blocks">Block descriptors</a> |
| 439 | </div> |
| 440 | |
| 441 | <div class="doc_text"> |
| 442 | |
| 443 | <pre> |
| 444 | %<a href="#format_blocks">llvm.dbg.block</a> = type { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 445 | uint, ;; Tag = 13 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block) |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 446 | { }* ;; Reference to context descriptor |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 447 | } |
| 448 | </pre> |
| 449 | |
| 450 | <p>These descriptors provide debug information about nested blocks within a |
| 451 | subprogram. The array of member descriptors is used to define local variables |
| 452 | and deeper nested blocks.</p> |
| 453 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 454 | </div> |
| 455 | |
| 456 | <!-- ======================================================================= --> |
| 457 | <div class="doc_subsubsection"> |
| 458 | <a name="format_basic_type">Basic type descriptors</a> |
| 459 | </div> |
| 460 | |
| 461 | <div class="doc_text"> |
| 462 | |
| 463 | <pre> |
| 464 | %<a href="#format_basic_type">llvm.dbg.basictype.type</a> = type { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 465 | uint, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_base_type) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 466 | { }*, ;; Reference to context (typically a compile unit) |
| 467 | sbyte*, ;; Name (may be "" for anonymous types) |
| 468 | { }*, ;; Reference to compile unit where defined (may be NULL) |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 469 | uint, ;; Line number where defined (may be 0) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 470 | uint, ;; Size in bits |
| 471 | uint, ;; Alignment in bits |
| 472 | uint, ;; Offset in bits |
| 473 | uint ;; Dwarf type encoding |
| 474 | } |
| 475 | </pre> |
| 476 | |
| 477 | <p>These descriptors define primitive types used in the code. Example int, bool |
| 478 | and float. The context provides the scope of the type, which is usually the top |
| 479 | level. Since basic types are not usually user defined the compile unit and line |
| 480 | number can be left as NULL and 0. The size, alignment and offset are expressed |
| 481 | in bits and can be 64 bit values. The alignment is used to round the offset |
| 482 | when embedded in a <a href="#format_composite_type">composite type</a> |
| 483 | (example to keep float doubles on 64 bit boundaries.) The offset is the bit |
| 484 | offset if embedded in a <a href="#format_composite_type">composite |
| 485 | type</a>.</p> |
| 486 | |
| 487 | <p>The type encoding provides the details of the type. The values are typically |
| 488 | one of the following;</p> |
| 489 | |
| 490 | <pre> |
| 491 | DW_ATE_address = 1 |
| 492 | DW_ATE_boolean = 2 |
| 493 | DW_ATE_float = 4 |
| 494 | DW_ATE_signed = 5 |
| 495 | DW_ATE_signed_char = 6 |
| 496 | DW_ATE_unsigned = 7 |
| 497 | DW_ATE_unsigned_char = 8 |
| 498 | </pre> |
| 499 | |
| 500 | </div> |
| 501 | |
| 502 | <!-- ======================================================================= --> |
| 503 | <div class="doc_subsubsection"> |
| 504 | <a name="format_derived_type">Derived type descriptors</a> |
| 505 | </div> |
| 506 | |
| 507 | <div class="doc_text"> |
| 508 | |
| 509 | <pre> |
| 510 | %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> = type { |
| 511 | uint, ;; Tag (see below) |
| 512 | { }*, ;; Reference to context |
| 513 | sbyte*, ;; Name (may be "" for anonymous types) |
| 514 | { }*, ;; Reference to compile unit where defined (may be NULL) |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 515 | uint, ;; Line number where defined (may be 0) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 516 | uint, ;; Size in bits |
| 517 | uint, ;; Alignment in bits |
| 518 | uint, ;; Offset in bits |
| 519 | { }* ;; Reference to type derived from |
| 520 | } |
| 521 | </pre> |
| 522 | |
| 523 | <p>These descriptors are used to define types derived from other types. The |
| 524 | value of the tag varies depending on the meaning. The following are possible |
| 525 | tag values;</p> |
| 526 | |
| 527 | <pre> |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 528 | DW_TAG_formal_parameter = 5 |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 529 | DW_TAG_member = 13 |
| 530 | DW_TAG_pointer_type = 15 |
| 531 | DW_TAG_reference_type = 16 |
| 532 | DW_TAG_typedef = 22 |
| 533 | DW_TAG_const_type = 38 |
| 534 | DW_TAG_volatile_type = 53 |
| 535 | DW_TAG_restrict_type = 55 |
| 536 | </pre> |
| 537 | |
| 538 | <p> <tt>DW_TAG_member</tt> is used to define a member of a <a |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 539 | href="#format_composite_type">composite type</a> or <a |
| 540 | href="#format_subprograms">subprogram</a>. The type of the member is the <a |
| 541 | href="#format_derived_type">derived type</a>. <tt>DW_TAG_formal_parameter</tt> |
| 542 | is used to define a member which is a formal argument of a subprogram.</p> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 543 | |
| 544 | <p><tt>DW_TAG_typedef</tt> is used to |
| 545 | provide a name for the derived type.</p> |
| 546 | |
| 547 | <p><tt>DW_TAG_pointer_type</tt>, |
| 548 | <tt>DW_TAG_reference_type</tt>, <tt>DW_TAG_const_type</tt>, |
| 549 | <tt>DW_TAG_volatile_type</tt> and <tt>DW_TAG_restrict_type</tt> are used to |
| 550 | qualify the <a href="#format_derived_type">derived type</a>. </p> |
| 551 | |
| 552 | <p><a href="#format_derived_type">Derived type</a> location can be determined |
| 553 | from the compile unit and line number. The size, alignment and offset are |
| 554 | expressed in bits and can be 64 bit values. The alignment is used to round the |
| 555 | offset when embedded in a <a href="#format_composite_type">composite type</a> |
| 556 | (example to keep float doubles on 64 bit boundaries.) The offset is the bit |
| 557 | offset if embedded in a <a href="#format_composite_type">composite |
| 558 | type</a>.</p> |
| 559 | |
| 560 | <p>Note that the <tt>void *</tt> type is expressed as a |
| 561 | <tt>llvm.dbg.derivedtype.type</tt> with tag of <tt>DW_TAG_pointer_type</tt> and |
| 562 | NULL derived type.</p> |
| 563 | |
| 564 | </div> |
| 565 | |
| 566 | <!-- ======================================================================= --> |
| 567 | <div class="doc_subsubsection"> |
| 568 | <a name="format_composite_type">Composite type descriptors</a> |
| 569 | </div> |
| 570 | |
| 571 | <div class="doc_text"> |
| 572 | |
| 573 | <pre> |
| 574 | %<a href="#format_composite_type">llvm.dbg.compositetype.type</a> = type { |
| 575 | uint, ;; Tag (see below) |
| 576 | { }*, ;; Reference to context |
| 577 | sbyte*, ;; Name (may be "" for anonymous types) |
| 578 | { }*, ;; Reference to compile unit where defined (may be NULL) |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 579 | uint, ;; Line number where defined (may be 0) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 580 | uint, ;; Size in bits |
| 581 | uint, ;; Alignment in bits |
| 582 | uint, ;; Offset in bits |
| 583 | { }* ;; Reference to array of member descriptors |
| 584 | } |
| 585 | </pre> |
| 586 | |
| 587 | <p>These descriptors are used to define types that are composed of 0 or more |
| 588 | elements. The value of the tag varies depending on the meaning. The following |
| 589 | are possible tag values;</p> |
| 590 | |
| 591 | <pre> |
| 592 | DW_TAG_array_type = 1 |
| 593 | DW_TAG_enumeration_type = 4 |
| 594 | DW_TAG_structure_type = 19 |
| 595 | DW_TAG_union_type = 23 |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 596 | DW_TAG_vector_type = 259 |
Jim Laskey | 094ee72 | 2006-06-20 21:13:20 +0000 | [diff] [blame] | 597 | DW_TAG_subroutine_type = 46 |
Jim Laskey | 4a9df24 | 2006-08-21 21:21:06 +0000 | [diff] [blame] | 598 | DW_TAG_inheritance = 26 |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 599 | </pre> |
| 600 | |
Jim Laskey | f8a01a9 | 2006-06-15 20:51:43 +0000 | [diff] [blame] | 601 | <p>The vector flag indicates that an array type is a native packed vector.</p> |
| 602 | |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 603 | <p>The members of array types (tag = <tt>DW_TAG_array_type</tt>) or vector types |
| 604 | (tag = <tt>DW_TAG_vector_type</tt>) are <a href="#format_subrange">subrange |
| 605 | descriptors</a>, each representing the range of subscripts at that level of |
| 606 | indexing.</p> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 607 | |
| 608 | <p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are |
| 609 | <a href="#format_enumeration">enumerator descriptors</a>, each representing the |
| 610 | definition of enumeration value |
| 611 | for the set.</p> |
| 612 | |
| 613 | <p>The members of structure (tag = <tt>DW_TAG_structure_type</tt>) or union (tag |
| 614 | = <tt>DW_TAG_union_type</tt>) types are any one of the <a |
| 615 | href="#format_basic_type">basic</a>, <a href="#format_derived_type">derived</a> |
| 616 | or <a href="#format_composite_type">composite</a> type descriptors, each |
| 617 | representing a field member of the structure or union.</p> |
| 618 | |
Jim Laskey | 4a9df24 | 2006-08-21 21:21:06 +0000 | [diff] [blame] | 619 | <p>For C++ classes (tag = <tt>DW_TAG_structure_type</tt>), member descriptors |
| 620 | provide information about base classes, static members and member functions. If |
| 621 | a member is a <a href="#format_derived_type">derived type descriptor</a> and has |
| 622 | a tag of <tt>DW_TAG_inheritance</tt>, then the type represents a base class. If |
| 623 | the member of is a <a href="#format_global_variables">global variable |
| 624 | descriptor</a> then it represents a static member. And, if the member is a <a |
| 625 | href="#format_subprograms">subprogram descriptor</a> then it represents a member |
| 626 | function. For static members and member functions, <tt>getName()</tt> returns |
| 627 | the members link or the C++ mangled name. <tt>getDisplayName()</tt> the |
| 628 | simplied version of the name.</p> |
| 629 | |
Jim Laskey | b329fe1 | 2006-06-21 11:08:10 +0000 | [diff] [blame] | 630 | <p>The first member of subroutine (tag = <tt>DW_TAG_subroutine_type</tt>) |
| 631 | type elements is the return type for the subroutine. The remaining |
Jim Laskey | 094ee72 | 2006-06-20 21:13:20 +0000 | [diff] [blame] | 632 | elements are the formal arguments to the subroutine.</p> |
| 633 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 634 | <p><a href="#format_composite_type">Composite type</a> location can be |
| 635 | determined from the compile unit and line number. The size, alignment and |
| 636 | offset are expressed in bits and can be 64 bit values. The alignment is used to |
| 637 | round the offset when embedded in a <a href="#format_composite_type">composite |
| 638 | type</a> (as an example, to keep float doubles on 64 bit boundaries.) The offset |
| 639 | is the bit offset if embedded in a <a href="#format_composite_type">composite |
| 640 | type</a>.</p> |
| 641 | |
| 642 | </div> |
| 643 | |
| 644 | <!-- ======================================================================= --> |
| 645 | <div class="doc_subsubsection"> |
| 646 | <a name="format_subrange">Subrange descriptors</a> |
| 647 | </div> |
| 648 | |
| 649 | <div class="doc_text"> |
| 650 | |
| 651 | <pre> |
| 652 | %<a href="#format_subrange">llvm.dbg.subrange.type</a> = type { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 653 | uint, ;; Tag = 33 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subrange_type) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 654 | uint, ;; Low value |
| 655 | uint ;; High value |
| 656 | } |
| 657 | </pre> |
| 658 | |
| 659 | <p>These descriptors are used to define ranges of array subscripts for an array |
| 660 | <a href="#format_composite_type">composite type</a>. The low value defines the |
| 661 | lower bounds typically zero for C/C++. The high value is the upper bounds. |
| 662 | Values are 64 bit. High - low + 1 is the size of the array. If |
| 663 | low == high the array will be unbounded.</p> |
| 664 | |
| 665 | </div> |
| 666 | |
| 667 | <!-- ======================================================================= --> |
| 668 | <div class="doc_subsubsection"> |
| 669 | <a name="format_enumeration">Enumerator descriptors</a> |
| 670 | </div> |
| 671 | |
| 672 | <div class="doc_text"> |
| 673 | |
| 674 | <pre> |
| 675 | %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> = type { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 676 | uint, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_enumerator) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 677 | sbyte*, ;; Name |
| 678 | uint ;; Value |
| 679 | } |
| 680 | </pre> |
| 681 | |
| 682 | <p>These descriptors are used to define members of an enumeration <a |
| 683 | href="#format_composite_type">composite type</a>, it associates the name to the |
| 684 | value.</p> |
| 685 | |
| 686 | </div> |
| 687 | |
| 688 | <!-- ======================================================================= --> |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 689 | <div class="doc_subsubsection"> |
| 690 | <a name="format_variables">Local variables</a> |
| 691 | </div> |
| 692 | |
| 693 | <div class="doc_text"> |
| 694 | <pre> |
| 695 | %<a href="#format_variables">llvm.dbg.variable.type</a> = type { |
| 696 | uint, ;; Tag (see below) |
| 697 | { }*, ;; Context |
| 698 | sbyte*, ;; Name |
| 699 | { }*, ;; Reference to compile unit where defined |
| 700 | uint, ;; Line number where defined |
| 701 | { }* ;; Type descriptor |
| 702 | } |
| 703 | </pre> |
| 704 | |
| 705 | <p>These descriptors are used to define variables local to a sub program. The |
| 706 | value of the tag depends on the usage of the variable;</p> |
| 707 | |
| 708 | <pre> |
| 709 | DW_TAG_auto_variable = 256 |
| 710 | DW_TAG_arg_variable = 257 |
| 711 | DW_TAG_return_variable = 258 |
| 712 | </pre> |
| 713 | |
| 714 | <p>An auto variable is any variable declared in the body of the function. An |
| 715 | argument variable is any variable that appears as a formal argument to the |
| 716 | function. A return variable is used to track the result of a function and has |
| 717 | no source correspondent.</p> |
| 718 | |
Jim Laskey | 2d395d9 | 2006-03-24 09:20:27 +0000 | [diff] [blame] | 719 | <p>The context is either the subprogram or block where the variable is defined. |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 720 | Name the source variable name. Compile unit and line indicate where the |
| 721 | variable was defined. Type descriptor defines the declared type of the |
| 722 | variable.</p> |
| 723 | |
| 724 | </div> |
| 725 | |
| 726 | <!-- ======================================================================= --> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 727 | <div class="doc_subsection"> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 728 | <a name="format_common_intrinsics">Debugger intrinsic functions</a> |
| 729 | </div> |
| 730 | |
| 731 | <div class="doc_text"> |
| 732 | |
| 733 | <p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to |
| 734 | provide debug information at various points in generated code.</p> |
| 735 | |
| 736 | </div> |
| 737 | |
| 738 | <!-- ======================================================================= --> |
| 739 | <div class="doc_subsubsection"> |
| 740 | <a name="format_common_stoppoint">llvm.dbg.stoppoint</a> |
| 741 | </div> |
| 742 | |
| 743 | <div class="doc_text"> |
| 744 | <pre> |
Jim Laskey | 108a638 | 2006-03-23 17:58:46 +0000 | [diff] [blame] | 745 | void %<a href="#format_common_stoppoint">llvm.dbg.stoppoint</a>( uint, uint, { }* ) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 746 | </pre> |
| 747 | |
| 748 | <p>This intrinsic is used to provide correspondence between the source file and |
| 749 | the generated code. The first argument is the line number (base 1), second |
| 750 | argument si the column number (0 if unknown) and the third argument the source |
Jim Laskey | 108a638 | 2006-03-23 17:58:46 +0000 | [diff] [blame] | 751 | <tt>%<a href="#format_compile_units">llvm.dbg.compile_unit</a>*</tt> cast to a |
| 752 | <tt>{ }*</tt>. Code following a call to this intrinsic will have been defined |
| 753 | in close proximity of the line, column and file. This information holds until |
| 754 | the next call to <tt>%<a |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 755 | href="#format_common_stoppoint">lvm.dbg.stoppoint</a></tt>.</p> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 756 | |
| 757 | </div> |
| 758 | |
| 759 | <!-- ======================================================================= --> |
| 760 | <div class="doc_subsubsection"> |
| 761 | <a name="format_common_func_start">llvm.dbg.func.start</a> |
| 762 | </div> |
| 763 | |
| 764 | <div class="doc_text"> |
| 765 | <pre> |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 766 | void %<a href="#format_common_func_start">llvm.dbg.func.start</a>( { }* ) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 767 | </pre> |
| 768 | |
| 769 | <p>This intrinsic is used to link the debug information in <tt>%<a |
| 770 | href="#format_subprograms">llvm.dbg.subprogram</a></tt> to the function. It also |
| 771 | defines the beginning of the function's declarative region (scope.) The |
| 772 | intrinsic should be called early in the function after the all the alloca |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 773 | instructions. It should be paired off with a closing <tt>%<a |
| 774 | href="#format_common_region_end">llvm.dbg.region.end</a></tt>. The function's |
| 775 | single argument is the <tt>%<a |
| 776 | href="#format_subprograms">llvm.dbg.subprogram.type</a></tt>.</p> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 777 | |
| 778 | </div> |
| 779 | |
| 780 | <!-- ======================================================================= --> |
| 781 | <div class="doc_subsubsection"> |
| 782 | <a name="format_common_region_start">llvm.dbg.region.start</a> |
| 783 | </div> |
| 784 | |
| 785 | <div class="doc_text"> |
| 786 | <pre> |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 787 | void %<a href="#format_common_region_start">llvm.dbg.region.start</a>( { }* ) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 788 | </pre> |
| 789 | |
| 790 | <p>This intrinsic is used to define the beginning of a declarative scope (ex. |
| 791 | block) for local language elements. It should be paired off with a closing |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 792 | <tt>%<a href="#format_common_region_end">llvm.dbg.region.end</a></tt>. The |
| 793 | function's single argument is the <tt>%<a |
| 794 | href="#format_blocks">llvm.dbg.block</a></tt> which is starting.</p> |
| 795 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 796 | |
| 797 | </div> |
| 798 | |
| 799 | <!-- ======================================================================= --> |
| 800 | <div class="doc_subsubsection"> |
| 801 | <a name="format_common_region_end">llvm.dbg.region.end</a> |
| 802 | </div> |
| 803 | |
| 804 | <div class="doc_text"> |
| 805 | <pre> |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 806 | void %<a href="#format_common_region_end">llvm.dbg.region.end</a>( { }* ) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 807 | </pre> |
| 808 | |
| 809 | <p>This intrinsic is used to define the end of a declarative scope (ex. block) |
| 810 | for local language elements. It should be paired off with an opening <tt>%<a |
| 811 | href="#format_common_region_start">llvm.dbg.region.start</a></tt> or <tt>%<a |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 812 | href="#format_common_func_start">llvm.dbg.func.start</a></tt>. The function's |
| 813 | single argument is either the <tt>%<a |
| 814 | href="#format_blocks">llvm.dbg.block</a></tt> or the <tt>%<a |
| 815 | href="#format_subprograms">llvm.dbg.subprogram.type</a></tt> which is |
| 816 | ending.</p> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 817 | |
| 818 | </div> |
| 819 | |
| 820 | <!-- ======================================================================= --> |
| 821 | <div class="doc_subsubsection"> |
| 822 | <a name="format_common_declare">llvm.dbg.declare</a> |
| 823 | </div> |
| 824 | |
| 825 | <div class="doc_text"> |
| 826 | <pre> |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 827 | void %<a href="#format_common_declare">llvm.dbg.declare</a>( { } *, { }* ) |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 828 | </pre> |
| 829 | |
Jim Laskey | 2d395d9 | 2006-03-24 09:20:27 +0000 | [diff] [blame] | 830 | <p>This intrinsic provides information about a local element (ex. variable.) The |
| 831 | first argument is the alloca for the variable, cast to a <tt>{ }*</tt>. The |
| 832 | second argument is the <tt>%<a |
| 833 | href="#format_variables">llvm.dbg.variable</a></tt> containing the description |
| 834 | of the variable, also cast to a <tt>{ }*</tt>.</p> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 835 | |
| 836 | </div> |
| 837 | |
| 838 | <!-- ======================================================================= --> |
| 839 | <div class="doc_subsection"> |
| 840 | <a name="format_common_stoppoints"> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 841 | Representing stopping points in the source program |
| 842 | </a> |
| 843 | </div> |
| 844 | |
| 845 | <div class="doc_text"> |
| 846 | |
| 847 | <p>LLVM debugger "stop points" are a key part of the debugging representation |
| 848 | that allows the LLVM to maintain simple semantics for <a |
| 849 | href="#debugopt">debugging optimized code</a>. The basic idea is that the |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 850 | front-end inserts calls to the <a |
| 851 | href="#format_common_stoppoint">%<tt>llvm.dbg.stoppoint</tt></a> intrinsic |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 852 | function at every point in the program where a debugger should be able to |
| 853 | inspect the program (these correspond to places a debugger stops when you |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 854 | "<tt>step</tt>" through it). The front-end can choose to place these as |
| 855 | fine-grained as it would like (for example, before every subexpression |
| 856 | evaluated), but it is recommended to only put them after every source statement |
| 857 | that includes executable code.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 858 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 859 | <p>Using calls to this intrinsic function to demark legal points for the |
| 860 | debugger to inspect the program automatically disables any optimizations that |
| 861 | could potentially confuse debugging information. To non-debug-information-aware |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 862 | transformations, these calls simply look like calls to an external function, |
| 863 | which they must assume to do anything (including reading or writing to any part |
| 864 | of reachable memory). On the other hand, it does not impact many optimizations, |
| 865 | such as code motion of non-trapping instructions, nor does it impact |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 866 | optimization of subexpressions, code duplication transformations, or basic-block |
| 867 | reordering transformations.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 868 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 869 | </div> |
| 870 | |
| 871 | |
| 872 | <!-- ======================================================================= --> |
| 873 | <div class="doc_subsection"> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 874 | <a name="format_common_lifetime">Object lifetimes and scoping</a> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 875 | </div> |
| 876 | |
| 877 | <div class="doc_text"> |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 878 | <p>In many languages, the local variables in functions can have their lifetime |
| 879 | or scope limited to a subset of a function. In the C family of languages, for |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 880 | example, variables are only live (readable and writable) within the source block |
| 881 | that they are defined in. In functional languages, values are only readable |
| 882 | after they have been defined. Though this is a very obvious concept, it is also |
| 883 | non-trivial to model in LLVM, because it has no notion of scoping in this sense, |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 884 | and does not want to be tied to a language's scoping rules.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 885 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 886 | <p>In order to handle this, the LLVM debug format uses the notion of "regions" |
| 887 | of a function, delineated by calls to intrinsic functions. These intrinsic |
| 888 | functions define new regions of the program and indicate when the region |
| 889 | lifetime expires. Consider the following C fragment, for example:</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 890 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 891 | <pre> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 892 | 1. void foo() { |
| 893 | 2. int X = ...; |
| 894 | 3. int Y = ...; |
| 895 | 4. { |
| 896 | 5. int Z = ...; |
| 897 | 6. ... |
| 898 | 7. } |
| 899 | 8. ... |
| 900 | 9. } |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 901 | </pre> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 902 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 903 | <p>Compiled to LLVM, this function would be represented like this:</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 904 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 905 | <pre> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 906 | void %foo() { |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 907 | entry: |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 908 | %X = alloca int |
| 909 | %Y = alloca int |
| 910 | %Z = alloca int |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 911 | |
| 912 | ... |
| 913 | |
| 914 | 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 ) |
| 915 | |
| 916 | 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 ) |
| 917 | |
| 918 | call void %<a href="#format_common_declare">llvm.dbg.declare</a>({}* %X, ...) |
| 919 | call void %<a href="#format_common_declare">llvm.dbg.declare</a>({}* %Y, ...) |
| 920 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 921 | <i>;; Evaluate expression on line 2, assigning to X.</i> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 922 | |
| 923 | 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 ) |
| 924 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 925 | <i>;; Evaluate expression on line 3, assigning to Y.</i> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 926 | |
| 927 | call void %<a href="#format_common_stoppoint">llvm.region.start</a>() |
| 928 | 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 ) |
| 929 | call void %<a href="#format_common_declare">llvm.dbg.declare</a>({}* %X, ...) |
| 930 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 931 | <i>;; Evaluate expression on line 5, assigning to Z.</i> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 932 | |
| 933 | 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 ) |
| 934 | call void %<a href="#format_common_region_end">llvm.region.end</a>() |
| 935 | |
| 936 | 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 ) |
| 937 | |
| 938 | call void %<a href="#format_common_region_end">llvm.region.end</a>() |
| 939 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 940 | ret void |
| 941 | } |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 942 | </pre> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 943 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 944 | <p>This example illustrates a few important details about the LLVM debugging |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 945 | information. In particular, it shows how the various intrinsics are applied |
| 946 | together to allow a debugger to analyze the relationship between statements, |
| 947 | variable definitions, and the code used to implement the function.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 948 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 949 | <p>The first intrinsic <tt>%<a |
| 950 | href="#format_common_func_start">llvm.dbg.func.start</a></tt> provides |
| 951 | a link with the <a href="#format_subprograms">subprogram descriptor</a> |
| 952 | containing the details of this function. This call also defines the beginning |
| 953 | of the function region, bounded by the <tt>%<a |
| 954 | href="#format_common_region_end">llvm.region.end</a></tt> at the end of |
| 955 | the function. This region is used to bracket the lifetime of variables declared |
| 956 | within. For a function, this outer region defines a new stack frame whose |
| 957 | lifetime ends when the region is ended.</p> |
| 958 | |
| 959 | <p>It is possible to define inner regions for short term variables by using the |
| 960 | %<a href="#format_common_stoppoint"><tt>llvm.region.start</tt></a> and <a |
| 961 | href="#format_common_region_end"><tt>%llvm.region.end</tt></a> to bound a |
| 962 | region. The inner region in this example would be for the block containing the |
| 963 | declaration of Z.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 964 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 965 | <p>Using regions to represent the boundaries of source-level functions allow |
| 966 | LLVM interprocedural optimizations to arbitrarily modify LLVM functions without |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 967 | having to worry about breaking mapping information between the LLVM code and the |
| 968 | and source-level program. In particular, the inliner requires no modification |
| 969 | to support inlining with debugging information: there is no explicit correlation |
| 970 | drawn between LLVM functions and their source-level counterparts (note however, |
| 971 | that if the inliner inlines all instances of a non-strong-linkage function into |
| 972 | its caller that it will not be possible for the user to manually invoke the |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 973 | inlined function from a debugger).</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 974 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 975 | <p>Once the function has been defined, the <a |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 976 | href="#format_common_stoppoint"><tt>stopping point</tt></a> corresponding to |
| 977 | line #2 (column #2) of the function is encountered. At this point in the |
| 978 | function, <b>no</b> local variables are live. As lines 2 and 3 of the example |
| 979 | are executed, their variable definitions are introduced into the program using |
| 980 | %<a href="#format_common_declare"><tt>llvm.dbg.declare</tt></a>, without the |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 981 | need to specify a new region. These variables do not require new regions to be |
| 982 | introduced because they go out of scope at the same point in the program: line |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 983 | 9.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 984 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 985 | <p>In contrast, the <tt>Z</tt> variable goes out of scope at a different time, |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 986 | on line 7. For this reason, it is defined within the inner region, which kills |
| 987 | the availability of <tt>Z</tt> before the code for line 8 is executed. In this |
| 988 | way, regions can support arbitrary source-language scoping rules, as long as |
| 989 | they can only be nested (ie, one scope cannot partially overlap with a part of |
| 990 | another scope).</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 991 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 992 | <p>It is worth noting that this scoping mechanism is used to control scoping of |
| 993 | all declarations, not just variable declarations. For example, the scope of a |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 994 | C++ using declaration is controlled with this couldchange how name lookup is |
| 995 | performed.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 996 | |
| 997 | </div> |
| 998 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 999 | |
| 1000 | |
| 1001 | <!-- *********************************************************************** --> |
| 1002 | <div class="doc_section"> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 1003 | <a name="ccxx_frontend">C/C++ front-end specific debug information</a> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1004 | </div> |
Misha Brukman | 94218a7 | 2004-12-09 20:27:37 +0000 | [diff] [blame] | 1005 | <!-- *********************************************************************** --> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1006 | |
| 1007 | <div class="doc_text"> |
| 1008 | |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 1009 | <p>The C and C++ front-ends represent information about the program in a format |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1010 | that is effectively identical to <a |
| 1011 | href="http://www.eagercon.com/dwarf/dwarf3std.htm">Dwarf 3.0</a> in terms of |
| 1012 | information content. This allows code generators to trivially support native |
| 1013 | debuggers by generating standard dwarf information, and contains enough |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 1014 | information for non-dwarf targets to translate it as needed.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1015 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1016 | <p>This section describes the forms used to represent C and C++ programs. Other |
| 1017 | languages could pattern themselves after this (which itself is tuned to |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 1018 | representing programs in the same way that Dwarf 3 does), or they could choose |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1019 | to provide completely different forms if they don't fit into the Dwarf model. |
| 1020 | As support for debugging information gets added to the various LLVM |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 1021 | source-language front-ends, the information used should be documented here.</p> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1022 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1023 | <p>The following sections provide examples of various C/C++ constructs and the |
| 1024 | debug information that would best describe those constructs.</p> |
| 1025 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1026 | </div> |
| 1027 | |
| 1028 | <!-- ======================================================================= --> |
| 1029 | <div class="doc_subsection"> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1030 | <a name="ccxx_compile_units">C/C++ source file information</a> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1031 | </div> |
| 1032 | |
| 1033 | <div class="doc_text"> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1034 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1035 | <p>Given the source files "MySource.cpp" and "MyHeader.h" located in the |
| 1036 | directory "/Users/mine/sources", the following code;</p> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 1037 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1038 | <pre> |
| 1039 | #include "MyHeader.h" |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 1040 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1041 | int main(int argc, char *argv[]) { |
| 1042 | return 0; |
| 1043 | } |
| 1044 | </pre> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 1045 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1046 | <p>a C/C++ front-end would generate the following descriptors;</p> |
| 1047 | |
| 1048 | <pre> |
| 1049 | ... |
| 1050 | ;; |
| 1051 | ;; Define types used. In this case we need one for compile unit anchors and one |
| 1052 | ;; for compile units. |
| 1053 | ;; |
| 1054 | %<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint } |
| 1055 | %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = type { uint, { }*, uint, uint, sbyte*, sbyte*, sbyte* } |
| 1056 | ... |
| 1057 | ;; |
| 1058 | ;; Define the anchor for compile units. Note that the second field of the |
| 1059 | ;; anchor is 17, which is the same as the tag for compile units |
| 1060 | ;; (17 = DW_TAG_compile_unit.) |
| 1061 | ;; |
| 1062 | %<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" |
| 1063 | |
| 1064 | ;; |
| 1065 | ;; Define the compile unit for the source file "/Users/mine/sources/MySource.cpp". |
| 1066 | ;; |
| 1067 | %<a href="#format_compile_units">llvm.dbg.compile_unit1</a> = internal constant %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1068 | uint add(uint 17, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1069 | { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_units</a> to { }*), |
| 1070 | uint 1, |
| 1071 | uint 1, |
| 1072 | sbyte* getelementptr ([13 x sbyte]* %str1, int 0, int 0), |
| 1073 | sbyte* getelementptr ([21 x sbyte]* %str2, int 0, int 0), |
| 1074 | sbyte* getelementptr ([33 x sbyte]* %str3, int 0, int 0) }, section "llvm.metadata" |
| 1075 | |
| 1076 | ;; |
| 1077 | ;; Define the compile unit for the header file "/Users/mine/sources/MyHeader.h". |
| 1078 | ;; |
| 1079 | %<a href="#format_compile_units">llvm.dbg.compile_unit2</a> = internal constant %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1080 | uint add(uint 17, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1081 | { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_units</a> to { }*), |
| 1082 | uint 1, |
| 1083 | uint 1, |
| 1084 | sbyte* getelementptr ([11 x sbyte]* %str4, int 0, int 0), |
| 1085 | sbyte* getelementptr ([21 x sbyte]* %str2, int 0, int 0), |
| 1086 | sbyte* getelementptr ([33 x sbyte]* %str3, int 0, int 0) }, section "llvm.metadata" |
| 1087 | |
| 1088 | ;; |
| 1089 | ;; Define each of the strings used in the compile units. |
| 1090 | ;; |
| 1091 | %str1 = internal constant [13 x sbyte] c"MySource.cpp\00", section "llvm.metadata"; |
| 1092 | %str2 = internal constant [21 x sbyte] c"/Users/mine/sources/\00", section "llvm.metadata"; |
| 1093 | %str3 = internal constant [33 x sbyte] c"4.0.1 LLVM (LLVM research group)\00", section "llvm.metadata"; |
| 1094 | %str4 = internal constant [11 x sbyte] c"MyHeader.h\00", section "llvm.metadata"; |
| 1095 | ... |
| 1096 | </pre> |
| 1097 | |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 1098 | </div> |
| 1099 | |
| 1100 | <!-- ======================================================================= --> |
| 1101 | <div class="doc_subsection"> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1102 | <a name="ccxx_global_variable">C/C++ global variable information</a> |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 1103 | </div> |
| 1104 | |
| 1105 | <div class="doc_text"> |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1106 | |
| 1107 | <p>Given an integer global variable declared as follows;</p> |
| 1108 | |
| 1109 | <pre> |
| 1110 | int MyGlobal = 100; |
| 1111 | </pre> |
| 1112 | |
| 1113 | <p>a C/C++ front-end would generate the following descriptors;</p> |
| 1114 | |
| 1115 | <pre> |
| 1116 | ;; |
| 1117 | ;; Define types used. One for global variable anchors, one for the global |
| 1118 | ;; variable descriptor, one for the global's basic type and one for the global's |
| 1119 | ;; compile unit. |
| 1120 | ;; |
| 1121 | %<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint } |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 1122 | %<a href="#format_global_variables">llvm.dbg.global_variable.type</a> = type { uint, { }*, { }*, sbyte*, { }*, uint, { }*, bool, bool, { }*, uint } |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1123 | %<a href="#format_basic_type">llvm.dbg.basictype.type</a> = type { uint, { }*, sbyte*, { }*, int, uint, uint, uint, uint } |
| 1124 | %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = ... |
| 1125 | ... |
| 1126 | ;; |
| 1127 | ;; Define the global itself. |
| 1128 | ;; |
| 1129 | %MyGlobal = global int 100 |
| 1130 | ... |
| 1131 | ;; |
| 1132 | ;; Define the anchor for global variables. Note that the second field of the |
| 1133 | ;; anchor is 52, which is the same as the tag for global variables |
| 1134 | ;; (52 = DW_TAG_variable.) |
| 1135 | ;; |
| 1136 | %<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" |
| 1137 | |
| 1138 | ;; |
| 1139 | ;; Define the global variable descriptor. Note the reference to the global |
| 1140 | ;; variable anchor and the global variable itself. |
| 1141 | ;; |
| 1142 | %<a href="#format_global_variables">llvm.dbg.global_variable</a> = internal constant %<a href="#format_global_variables">llvm.dbg.global_variable.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1143 | uint add(uint 52, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1144 | { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_global_variables">llvm.dbg.global_variables</a> to { }*), |
| 1145 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1146 | sbyte* getelementptr ([9 x sbyte]* %str1, int 0, int 0), |
Jim Laskey | 5682aff | 2006-08-21 22:57:31 +0000 | [diff] [blame] | 1147 | sbyte* getelementptr ([1 x sbyte]* %str2, int 0, int 0), |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 1148 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1149 | uint 1, |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1150 | { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*), |
| 1151 | bool false, |
| 1152 | bool true, |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 1153 | { }* cast (int* %MyGlobal to { }*) }, section "llvm.metadata" |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1154 | |
| 1155 | ;; |
| 1156 | ;; Define the basic type of 32 bit signed integer. Note that since int is an |
| 1157 | ;; intrinsic type the source file is NULL and line 0. |
| 1158 | ;; |
| 1159 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1160 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1161 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
Jim Laskey | 5682aff | 2006-08-21 22:57:31 +0000 | [diff] [blame] | 1162 | sbyte* getelementptr ([4 x sbyte]* %str3, int 0, int 0), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1163 | { }* null, |
| 1164 | int 0, |
| 1165 | uint 32, |
| 1166 | uint 32, |
| 1167 | uint 0, |
| 1168 | uint 5 }, section "llvm.metadata" |
| 1169 | |
| 1170 | ;; |
| 1171 | ;; Define the names of the global variable and basic type. |
| 1172 | ;; |
| 1173 | %str1 = internal constant [9 x sbyte] c"MyGlobal\00", section "llvm.metadata" |
Jim Laskey | 5682aff | 2006-08-21 22:57:31 +0000 | [diff] [blame] | 1174 | %str2 = internal constant [1 x sbyte] c"\00", section "llvm.metadata" |
| 1175 | %str3 = internal constant [4 x sbyte] c"int\00", section "llvm.metadata" |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1176 | </pre> |
| 1177 | |
Chris Lattner | 8ff7590 | 2004-01-06 05:31:32 +0000 | [diff] [blame] | 1178 | </div> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1179 | |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1180 | <!-- ======================================================================= --> |
| 1181 | <div class="doc_subsection"> |
| 1182 | <a name="ccxx_subprogram">C/C++ function information</a> |
| 1183 | </div> |
| 1184 | |
| 1185 | <div class="doc_text"> |
| 1186 | |
| 1187 | <p>Given a function declared as follows;</p> |
| 1188 | |
| 1189 | <pre> |
| 1190 | int main(int argc, char *argv[]) { |
| 1191 | return 0; |
| 1192 | } |
| 1193 | </pre> |
| 1194 | |
| 1195 | <p>a C/C++ front-end would generate the following descriptors;</p> |
| 1196 | |
| 1197 | <pre> |
| 1198 | ;; |
| 1199 | ;; Define types used. One for subprogram anchors, one for the subprogram |
| 1200 | ;; descriptor, one for the global's basic type and one for the subprogram's |
| 1201 | ;; compile unit. |
| 1202 | ;; |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 1203 | %<a href="#format_subprograms">llvm.dbg.subprogram.type</a> = type { uint, { }*, { }*, sbyte*, { }*, bool, bool } |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1204 | %<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint } |
| 1205 | %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = ... |
| 1206 | |
| 1207 | ;; |
| 1208 | ;; Define the anchor for subprograms. Note that the second field of the |
| 1209 | ;; anchor is 46, which is the same as the tag for subprograms |
| 1210 | ;; (46 = DW_TAG_subprogram.) |
| 1211 | ;; |
| 1212 | %<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" |
| 1213 | |
| 1214 | ;; |
| 1215 | ;; Define the descriptor for the subprogram. TODO - more details. |
| 1216 | ;; |
| 1217 | %<a href="#format_subprograms">llvm.dbg.subprogram</a> = internal constant %<a href="#format_subprograms">llvm.dbg.subprogram.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1218 | uint add(uint 46, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1219 | { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_subprograms">llvm.dbg.subprograms</a> to { }*), |
| 1220 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1221 | sbyte* getelementptr ([5 x sbyte]* %str1, int 0, int 0), |
Jim Laskey | 5682aff | 2006-08-21 22:57:31 +0000 | [diff] [blame] | 1222 | sbyte* getelementptr ([1 x sbyte]* %str2, int 0, int 0), |
Jim Laskey | 3d11bee | 2006-03-15 19:10:52 +0000 | [diff] [blame] | 1223 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1224 | uint 1, |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1225 | { }* null, |
| 1226 | bool false, |
Jim Laskey | 383e009 | 2006-03-23 17:54:33 +0000 | [diff] [blame] | 1227 | bool true }, section "llvm.metadata" |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1228 | |
| 1229 | ;; |
| 1230 | ;; Define the name of the subprogram. |
| 1231 | ;; |
| 1232 | %str1 = internal constant [5 x sbyte] c"main\00", section "llvm.metadata" |
Jim Laskey | 5682aff | 2006-08-21 22:57:31 +0000 | [diff] [blame] | 1233 | %str2 = internal constant [1 x sbyte] c"\00", section "llvm.metadata" |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1234 | |
| 1235 | ;; |
| 1236 | ;; Define the subprogram itself. |
| 1237 | ;; |
| 1238 | int %main(int %argc, sbyte** %argv) { |
| 1239 | ... |
| 1240 | } |
| 1241 | </pre> |
| 1242 | |
| 1243 | </div> |
| 1244 | |
| 1245 | <!-- ======================================================================= --> |
| 1246 | <div class="doc_subsection"> |
| 1247 | <a name="ccxx_basic_types">C/C++ basic types</a> |
| 1248 | </div> |
| 1249 | |
| 1250 | <div class="doc_text"> |
| 1251 | |
| 1252 | <p>The following are the basic type descriptors for C/C++ core types;</p> |
| 1253 | |
| 1254 | </div> |
| 1255 | |
| 1256 | <!-- ======================================================================= --> |
| 1257 | <div class="doc_subsubsection"> |
| 1258 | <a name="ccxx_basic_type_bool">bool</a> |
| 1259 | </div> |
| 1260 | |
| 1261 | <div class="doc_text"> |
| 1262 | |
| 1263 | <pre> |
| 1264 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1265 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1266 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1267 | sbyte* getelementptr ([5 x sbyte]* %str1, int 0, int 0), |
| 1268 | { }* null, |
| 1269 | int 0, |
| 1270 | uint 32, |
| 1271 | uint 32, |
| 1272 | uint 0, |
| 1273 | uint 2 }, section "llvm.metadata" |
| 1274 | %str1 = internal constant [5 x sbyte] c"bool\00", section "llvm.metadata" |
| 1275 | </pre> |
| 1276 | |
| 1277 | </div> |
| 1278 | |
| 1279 | <!-- ======================================================================= --> |
| 1280 | <div class="doc_subsubsection"> |
| 1281 | <a name="ccxx_basic_char">char</a> |
| 1282 | </div> |
| 1283 | |
| 1284 | <div class="doc_text"> |
| 1285 | |
| 1286 | <pre> |
| 1287 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1288 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1289 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1290 | sbyte* getelementptr ([5 x sbyte]* %str1, int 0, int 0), |
| 1291 | { }* null, |
| 1292 | int 0, |
| 1293 | uint 8, |
| 1294 | uint 8, |
| 1295 | uint 0, |
| 1296 | uint 6 }, section "llvm.metadata" |
| 1297 | %str1 = internal constant [5 x sbyte] c"char\00", section "llvm.metadata" |
| 1298 | </pre> |
| 1299 | |
| 1300 | </div> |
| 1301 | |
| 1302 | <!-- ======================================================================= --> |
| 1303 | <div class="doc_subsubsection"> |
| 1304 | <a name="ccxx_basic_unsigned_char">unsigned char</a> |
| 1305 | </div> |
| 1306 | |
| 1307 | <div class="doc_text"> |
| 1308 | |
| 1309 | <pre> |
| 1310 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1311 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1312 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1313 | sbyte* getelementptr ([14 x sbyte]* %str1, int 0, int 0), |
| 1314 | { }* null, |
| 1315 | int 0, |
| 1316 | uint 8, |
| 1317 | uint 8, |
| 1318 | uint 0, |
| 1319 | uint 8 }, section "llvm.metadata" |
| 1320 | %str1 = internal constant [14 x sbyte] c"unsigned char\00", section "llvm.metadata" |
| 1321 | </pre> |
| 1322 | |
| 1323 | </div> |
| 1324 | |
| 1325 | <!-- ======================================================================= --> |
| 1326 | <div class="doc_subsubsection"> |
| 1327 | <a name="ccxx_basic_short">short</a> |
| 1328 | </div> |
| 1329 | |
| 1330 | <div class="doc_text"> |
| 1331 | |
| 1332 | <pre> |
| 1333 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1334 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1335 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1336 | sbyte* getelementptr ([10 x sbyte]* %str1, int 0, int 0), |
| 1337 | { }* null, |
| 1338 | int 0, |
| 1339 | uint 16, |
| 1340 | uint 16, |
| 1341 | uint 0, |
| 1342 | uint 5 }, section "llvm.metadata" |
| 1343 | %str1 = internal constant [10 x sbyte] c"short int\00", section "llvm.metadata" |
| 1344 | </pre> |
| 1345 | |
| 1346 | </div> |
| 1347 | |
| 1348 | <!-- ======================================================================= --> |
| 1349 | <div class="doc_subsubsection"> |
| 1350 | <a name="ccxx_basic_unsigned_short">unsigned short</a> |
| 1351 | </div> |
| 1352 | |
| 1353 | <div class="doc_text"> |
| 1354 | |
| 1355 | <pre> |
| 1356 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1357 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1358 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1359 | sbyte* getelementptr ([19 x sbyte]* %str1, int 0, int 0), |
| 1360 | { }* null, |
| 1361 | int 0, |
| 1362 | uint 16, |
| 1363 | uint 16, |
| 1364 | uint 0, |
| 1365 | uint 7 }, section "llvm.metadata" |
| 1366 | %str1 = internal constant [19 x sbyte] c"short unsigned int\00", section "llvm.metadata" |
| 1367 | </pre> |
| 1368 | |
| 1369 | </div> |
| 1370 | |
| 1371 | <!-- ======================================================================= --> |
| 1372 | <div class="doc_subsubsection"> |
| 1373 | <a name="ccxx_basic_int">int</a> |
| 1374 | </div> |
| 1375 | |
| 1376 | <div class="doc_text"> |
| 1377 | |
| 1378 | <pre> |
| 1379 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1380 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1381 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1382 | sbyte* getelementptr ([4 x sbyte]* %str1, int 0, int 0), |
| 1383 | { }* null, |
| 1384 | int 0, |
| 1385 | uint 32, |
| 1386 | uint 32, |
| 1387 | uint 0, |
| 1388 | uint 5 }, section "llvm.metadata" |
| 1389 | %str1 = internal constant [4 x sbyte] c"int\00", section "llvm.metadata" |
| 1390 | </pre> |
| 1391 | |
| 1392 | </div> |
| 1393 | |
| 1394 | <!-- ======================================================================= --> |
| 1395 | <div class="doc_subsubsection"> |
| 1396 | <a name="ccxx_basic_unsigned_int">unsigned int</a> |
| 1397 | </div> |
| 1398 | |
| 1399 | <div class="doc_text"> |
| 1400 | |
| 1401 | <pre> |
| 1402 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1403 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1404 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1405 | sbyte* getelementptr ([13 x sbyte]* %str1, int 0, int 0), |
| 1406 | { }* null, |
| 1407 | int 0, |
| 1408 | uint 32, |
| 1409 | uint 32, |
| 1410 | uint 0, |
| 1411 | uint 7 }, section "llvm.metadata" |
| 1412 | %str1 = internal constant [13 x sbyte] c"unsigned int\00", section "llvm.metadata" |
| 1413 | </pre> |
| 1414 | |
| 1415 | </div> |
| 1416 | |
| 1417 | <!-- ======================================================================= --> |
| 1418 | <div class="doc_subsubsection"> |
| 1419 | <a name="ccxx_basic_long_long">long long</a> |
| 1420 | </div> |
| 1421 | |
| 1422 | <div class="doc_text"> |
| 1423 | |
| 1424 | <pre> |
| 1425 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1426 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1427 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1428 | sbyte* getelementptr ([14 x sbyte]* %str1, int 0, int 0), |
| 1429 | { }* null, |
| 1430 | int 0, |
| 1431 | uint 64, |
| 1432 | uint 64, |
| 1433 | uint 0, |
| 1434 | uint 5 }, section "llvm.metadata" |
| 1435 | %str1 = internal constant [14 x sbyte] c"long long int\00", section "llvm.metadata" |
| 1436 | </pre> |
| 1437 | |
| 1438 | </div> |
| 1439 | |
| 1440 | <!-- ======================================================================= --> |
| 1441 | <div class="doc_subsubsection"> |
| 1442 | <a name="ccxx_basic_unsigned_long_long">unsigned long long</a> |
| 1443 | </div> |
| 1444 | |
| 1445 | <div class="doc_text"> |
| 1446 | |
| 1447 | <pre> |
| 1448 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1449 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1450 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1451 | sbyte* getelementptr ([23 x sbyte]* %str1, int 0, int 0), |
| 1452 | { }* null, |
| 1453 | int 0, |
| 1454 | uint 64, |
| 1455 | uint 64, |
| 1456 | uint 0, |
| 1457 | uint 7 }, section "llvm.metadata" |
| 1458 | %str1 = internal constant [23 x sbyte] c"long long unsigned int\00", section "llvm.metadata" |
| 1459 | </pre> |
| 1460 | |
| 1461 | </div> |
| 1462 | |
| 1463 | <!-- ======================================================================= --> |
| 1464 | <div class="doc_subsubsection"> |
| 1465 | <a name="ccxx_basic_float">float</a> |
| 1466 | </div> |
| 1467 | |
| 1468 | <div class="doc_text"> |
| 1469 | |
| 1470 | <pre> |
| 1471 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1472 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1473 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1474 | sbyte* getelementptr ([6 x sbyte]* %str1, int 0, int 0), |
| 1475 | { }* null, |
| 1476 | int 0, |
| 1477 | uint 32, |
| 1478 | uint 32, |
| 1479 | uint 0, |
| 1480 | uint 4 }, section "llvm.metadata" |
| 1481 | %str1 = internal constant [6 x sbyte] c"float\00", section "llvm.metadata" |
| 1482 | </pre> |
| 1483 | |
| 1484 | </div> |
| 1485 | |
| 1486 | <!-- ======================================================================= --> |
| 1487 | <div class="doc_subsubsection"> |
| 1488 | <a name="ccxx_basic_double">double</a> |
| 1489 | </div> |
| 1490 | |
| 1491 | <div class="doc_text"> |
| 1492 | |
| 1493 | <pre> |
| 1494 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1495 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1496 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1497 | sbyte* getelementptr ([7 x sbyte]* %str1, int 0, int 0), |
| 1498 | { }* null, |
| 1499 | int 0, |
| 1500 | uint 64, |
| 1501 | uint 64, |
| 1502 | uint 0, |
| 1503 | uint 4 }, section "llvm.metadata" |
| 1504 | %str1 = internal constant [7 x sbyte] c"double\00", section "llvm.metadata" |
| 1505 | </pre> |
| 1506 | |
| 1507 | </div> |
| 1508 | |
| 1509 | <!-- ======================================================================= --> |
| 1510 | <div class="doc_subsection"> |
| 1511 | <a name="ccxx_derived_types">C/C++ derived types</a> |
| 1512 | </div> |
| 1513 | |
| 1514 | <div class="doc_text"> |
| 1515 | |
| 1516 | <p>Given the following as an example of C/C++ derived type;</p> |
| 1517 | |
| 1518 | <pre> |
| 1519 | typedef const int *IntPtr; |
| 1520 | </pre> |
| 1521 | |
| 1522 | <p>a C/C++ front-end would generate the following descriptors;</p> |
| 1523 | |
| 1524 | <pre> |
| 1525 | ;; |
| 1526 | ;; Define the typedef "IntPtr". |
| 1527 | ;; |
| 1528 | %<a href="#format_derived_type">llvm.dbg.derivedtype1</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1529 | uint add(uint 22, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1530 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1531 | sbyte* getelementptr ([7 x sbyte]* %str1, int 0, int 0), |
| 1532 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1533 | int 1, |
| 1534 | uint 0, |
| 1535 | uint 0, |
| 1536 | uint 0, |
| 1537 | { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype2</a> to { }*) }, section "llvm.metadata" |
| 1538 | %str1 = internal constant [7 x sbyte] c"IntPtr\00", section "llvm.metadata" |
| 1539 | |
| 1540 | ;; |
| 1541 | ;; Define the pointer type. |
| 1542 | ;; |
| 1543 | %<a href="#format_derived_type">llvm.dbg.derivedtype2</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1544 | uint add(uint 15, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1545 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
Jim Laskey | 4d9b10b | 2006-03-14 18:50:50 +0000 | [diff] [blame] | 1546 | sbyte* null, |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1547 | { }* null, |
| 1548 | int 0, |
| 1549 | uint 32, |
| 1550 | uint 32, |
| 1551 | uint 0, |
| 1552 | { }* 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 Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1553 | |
| 1554 | ;; |
| 1555 | ;; Define the const type. |
| 1556 | ;; |
| 1557 | %<a href="#format_derived_type">llvm.dbg.derivedtype3</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1558 | uint add(uint 38, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1559 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
Jim Laskey | 4d9b10b | 2006-03-14 18:50:50 +0000 | [diff] [blame] | 1560 | sbyte* null, |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1561 | { }* null, |
| 1562 | int 0, |
| 1563 | uint 0, |
| 1564 | uint 0, |
| 1565 | uint 0, |
| 1566 | { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype1</a> to { }*) }, section "llvm.metadata" |
| 1567 | |
| 1568 | ;; |
| 1569 | ;; Define the int type. |
| 1570 | ;; |
| 1571 | %<a href="#format_basic_type">llvm.dbg.basictype1</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1572 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1573 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
Jim Laskey | 4d9b10b | 2006-03-14 18:50:50 +0000 | [diff] [blame] | 1574 | sbyte* getelementptr ([4 x sbyte]* %str2, int 0, int 0), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1575 | { }* null, |
| 1576 | int 0, |
| 1577 | uint 32, |
| 1578 | uint 32, |
| 1579 | uint 0, |
| 1580 | uint 5 }, section "llvm.metadata" |
Jim Laskey | 4d9b10b | 2006-03-14 18:50:50 +0000 | [diff] [blame] | 1581 | %str2 = internal constant [4 x sbyte] c"int\00", section "llvm.metadata" |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1582 | </pre> |
| 1583 | |
| 1584 | </div> |
| 1585 | |
| 1586 | <!-- ======================================================================= --> |
| 1587 | <div class="doc_subsection"> |
| 1588 | <a name="ccxx_composite_types">C/C++ struct/union types</a> |
| 1589 | </div> |
| 1590 | |
| 1591 | <div class="doc_text"> |
| 1592 | |
| 1593 | <p>Given the following as an example of C/C++ struct type;</p> |
| 1594 | |
| 1595 | <pre> |
| 1596 | struct Color { |
| 1597 | unsigned Red; |
| 1598 | unsigned Green; |
| 1599 | unsigned Blue; |
| 1600 | }; |
| 1601 | </pre> |
| 1602 | |
| 1603 | <p>a C/C++ front-end would generate the following descriptors;</p> |
| 1604 | |
| 1605 | <pre> |
| 1606 | ;; |
| 1607 | ;; Define basic type for unsigned int. |
| 1608 | ;; |
| 1609 | %<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1610 | uint add(uint 36, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1611 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1612 | sbyte* getelementptr ([13 x sbyte]* %str1, int 0, int 0), |
| 1613 | { }* null, |
| 1614 | int 0, |
| 1615 | uint 32, |
| 1616 | uint 32, |
| 1617 | uint 0, |
| 1618 | uint 7 }, section "llvm.metadata" |
| 1619 | %str1 = internal constant [13 x sbyte] c"unsigned int\00", section "llvm.metadata" |
| 1620 | |
| 1621 | ;; |
| 1622 | ;; Define composite type for struct Color. |
| 1623 | ;; |
| 1624 | %<a href="#format_composite_type">llvm.dbg.compositetype</a> = internal constant %<a href="#format_composite_type">llvm.dbg.compositetype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1625 | uint add(uint 19, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1626 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1627 | sbyte* getelementptr ([6 x sbyte]* %str2, int 0, int 0), |
| 1628 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1629 | int 1, |
| 1630 | uint 96, |
| 1631 | uint 32, |
| 1632 | uint 0, |
Jim Laskey | f8a01a9 | 2006-06-15 20:51:43 +0000 | [diff] [blame] | 1633 | { }* null, |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1634 | { }* cast ([3 x { }*]* %llvm.dbg.array to { }*) }, section "llvm.metadata" |
| 1635 | %str2 = internal constant [6 x sbyte] c"Color\00", section "llvm.metadata" |
| 1636 | |
| 1637 | ;; |
| 1638 | ;; Define the Red field. |
| 1639 | ;; |
| 1640 | %<a href="#format_derived_type">llvm.dbg.derivedtype1</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1641 | uint add(uint 13, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1642 | { }* null, |
| 1643 | sbyte* getelementptr ([4 x sbyte]* %str3, int 0, int 0), |
| 1644 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1645 | int 2, |
| 1646 | uint 32, |
| 1647 | uint 32, |
| 1648 | uint 0, |
| 1649 | { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata" |
| 1650 | %str3 = internal constant [4 x sbyte] c"Red\00", section "llvm.metadata" |
| 1651 | |
| 1652 | ;; |
| 1653 | ;; Define the Green field. |
| 1654 | ;; |
| 1655 | %<a href="#format_derived_type">llvm.dbg.derivedtype2</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1656 | uint add(uint 13, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1657 | { }* null, |
| 1658 | sbyte* getelementptr ([6 x sbyte]* %str4, int 0, int 0), |
| 1659 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1660 | int 3, |
| 1661 | uint 32, |
| 1662 | uint 32, |
| 1663 | uint 32, |
| 1664 | { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata" |
| 1665 | %str4 = internal constant [6 x sbyte] c"Green\00", section "llvm.metadata" |
| 1666 | |
| 1667 | ;; |
| 1668 | ;; Define the Blue field. |
| 1669 | ;; |
| 1670 | %<a href="#format_derived_type">llvm.dbg.derivedtype3</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1671 | uint add(uint 13, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1672 | { }* null, |
| 1673 | sbyte* getelementptr ([5 x sbyte]* %str5, int 0, int 0), |
| 1674 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1675 | int 4, |
| 1676 | uint 32, |
| 1677 | uint 32, |
| 1678 | uint 64, |
| 1679 | { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata" |
| 1680 | %str5 = internal constant [5 x sbyte] c"Blue\00", section "llvm.metadata" |
| 1681 | |
| 1682 | ;; |
| 1683 | ;; Define the array of fields used by the composite type Color. |
| 1684 | ;; |
| 1685 | %llvm.dbg.array = internal constant [3 x { }*] [ |
| 1686 | { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype1</a> to { }*), |
| 1687 | { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype2</a> to { }*), |
| 1688 | { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype3</a> to { }*) ], section "llvm.metadata" |
| 1689 | </pre> |
| 1690 | |
| 1691 | </div> |
| 1692 | |
| 1693 | <!-- ======================================================================= --> |
| 1694 | <div class="doc_subsection"> |
| 1695 | <a name="ccxx_enumeration_types">C/C++ enumeration types</a> |
| 1696 | </div> |
| 1697 | |
| 1698 | <div class="doc_text"> |
| 1699 | |
| 1700 | <p>Given the following as an example of C/C++ enumeration type;</p> |
| 1701 | |
| 1702 | <pre> |
| 1703 | enum Trees { |
| 1704 | Spruce = 100, |
| 1705 | Oak = 200, |
| 1706 | Maple = 300 |
| 1707 | }; |
| 1708 | </pre> |
| 1709 | |
| 1710 | <p>a C/C++ front-end would generate the following descriptors;</p> |
| 1711 | |
| 1712 | <pre> |
| 1713 | ;; |
| 1714 | ;; Define composite type for enum Trees |
| 1715 | ;; |
| 1716 | %<a href="#format_composite_type">llvm.dbg.compositetype</a> = internal constant %<a href="#format_composite_type">llvm.dbg.compositetype.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1717 | uint add(uint 4, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1718 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1719 | sbyte* getelementptr ([6 x sbyte]* %str1, int 0, int 0), |
| 1720 | { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*), |
| 1721 | int 1, |
| 1722 | uint 32, |
| 1723 | uint 32, |
| 1724 | uint 0, |
| 1725 | { }* null, |
| 1726 | { }* cast ([3 x { }*]* %llvm.dbg.array to { }*) }, section "llvm.metadata" |
| 1727 | %str1 = internal constant [6 x sbyte] c"Trees\00", section "llvm.metadata" |
| 1728 | |
| 1729 | ;; |
| 1730 | ;; Define Spruce enumerator. |
| 1731 | ;; |
| 1732 | %<a href="#format_enumeration">llvm.dbg.enumerator1</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1733 | uint add(uint 40, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1734 | sbyte* getelementptr ([7 x sbyte]* %str2, int 0, int 0), |
| 1735 | int 100 }, section "llvm.metadata" |
| 1736 | %str2 = internal constant [7 x sbyte] c"Spruce\00", section "llvm.metadata" |
| 1737 | |
| 1738 | ;; |
| 1739 | ;; Define Oak enumerator. |
| 1740 | ;; |
| 1741 | %<a href="#format_enumeration">llvm.dbg.enumerator2</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1742 | uint add(uint 40, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1743 | sbyte* getelementptr ([4 x sbyte]* %str3, int 0, int 0), |
| 1744 | int 200 }, section "llvm.metadata" |
| 1745 | %str3 = internal constant [4 x sbyte] c"Oak\00", section "llvm.metadata" |
| 1746 | |
| 1747 | ;; |
| 1748 | ;; Define Maple enumerator. |
| 1749 | ;; |
| 1750 | %<a href="#format_enumeration">llvm.dbg.enumerator3</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> { |
Jim Laskey | 7089f45 | 2006-06-16 13:14:03 +0000 | [diff] [blame] | 1751 | uint add(uint 40, uint 262144), |
Jim Laskey | cec12a5 | 2006-03-14 18:08:46 +0000 | [diff] [blame] | 1752 | sbyte* getelementptr ([6 x sbyte]* %str4, int 0, int 0), |
| 1753 | int 300 }, section "llvm.metadata" |
| 1754 | %str4 = internal constant [6 x sbyte] c"Maple\00", section "llvm.metadata" |
| 1755 | |
| 1756 | ;; |
| 1757 | ;; Define the array of enumerators used by composite type Trees. |
| 1758 | ;; |
| 1759 | %llvm.dbg.array = internal constant [3 x { }*] [ |
| 1760 | { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator1</a> to { }*), |
| 1761 | { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator2</a> to { }*), |
| 1762 | { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator3</a> to { }*) ], section "llvm.metadata" |
| 1763 | </pre> |
| 1764 | |
| 1765 | </div> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1766 | |
| 1767 | <!-- *********************************************************************** --> |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 1768 | |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1769 | <hr> |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 1770 | <address> |
| 1771 | <a href="http://jigsaw.w3.org/css-validator/check/referer"><img |
| 1772 | src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a> |
| 1773 | <a href="http://validator.w3.org/check/referer"><img |
| 1774 | src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a> |
| 1775 | |
| 1776 | <a href="mailto:sabre@nondot.org">Chris Lattner</a><br> |
Reid Spencer | 05fe4b0 | 2006-03-14 05:39:39 +0000 | [diff] [blame] | 1777 | <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1778 | Last modified: $Date$ |
Misha Brukman | 8287373 | 2004-05-12 19:21:57 +0000 | [diff] [blame] | 1779 | </address> |
Chris Lattner | bdfb339 | 2004-01-05 05:06:33 +0000 | [diff] [blame] | 1780 | |
| 1781 | </body> |
| 1782 | </html> |