diff options
Diffstat (limited to 'docs/SourceLevelDebugging.html')
| -rw-r--r-- | docs/SourceLevelDebugging.html | 321 |
1 files changed, 172 insertions, 149 deletions
diff --git a/docs/SourceLevelDebugging.html b/docs/SourceLevelDebugging.html index 186ea4a..4cfb52e 100644 --- a/docs/SourceLevelDebugging.html +++ b/docs/SourceLevelDebugging.html @@ -8,7 +8,7 @@ </head> <body> -<div class="doc_title">Source Level Debugging with LLVM</div> +<h1>Source Level Debugging with LLVM</h1> <table class="layout" style="width:100%"> <tr class="layout"> @@ -68,10 +68,10 @@ height="369"> <!-- *********************************************************************** --> -<div class="doc_section"><a name="introduction">Introduction</a></div> +<h2><a name="introduction">Introduction</a></h2> <!-- *********************************************************************** --> -<div class="doc_text"> +<div> <p>This document is the central repository for all information pertaining to debug information in LLVM. It describes the <a href="#format">actual format @@ -80,14 +80,12 @@ height="369"> Further, this document provides specific examples of what debug information for C/C++ looks like.</p> -</div> - <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="phil">Philosophy behind LLVM debugging information</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>The idea of the LLVM debugging information is to capture how the important pieces of the source-language's Abstract Syntax Tree map onto LLVM code. @@ -133,11 +131,11 @@ height="369"> </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="consumers">Debug information consumers</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>The role of debug information is to provide meta information normally stripped away during the compilation process. This meta information provides @@ -157,11 +155,11 @@ height="369"> </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="debugopt">Debugging optimized code</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>An extremely high priority of LLVM debugging information is to make it interact well with optimizations and analysis. In particular, the LLVM debug @@ -226,13 +224,15 @@ height="369"> </div> +</div> + <!-- *********************************************************************** --> -<div class="doc_section"> +<h2> <a name="format">Debugging information format</a> -</div> +</h2> <!-- *********************************************************************** --> -<div class="doc_text"> +<div> <p>LLVM debugging information has been carefully designed to make it possible for the optimizer to optimize the program and debugging information without @@ -265,14 +265,12 @@ height="369"> common to any source-language. The <a href="#ccxx_frontend">next section</a> describes the data layout conventions used by the C and C++ front-ends.</p> -</div> - <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="debug_info_descriptors">Debug information descriptors</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>In consideration of the complexity and volume of debug information, LLVM provides a specification for well formed debug descriptors. </p> @@ -312,14 +310,12 @@ height="369"> <p>The details of the various descriptors follow.</p> -</div> - <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_compile_units">Compile unit descriptors</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -351,11 +347,11 @@ height="369"> </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_files">File descriptors</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -380,11 +376,11 @@ height="369"> </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_global_variables">Global variable descriptors</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -407,16 +403,17 @@ height="369"> </div> <p>These descriptors provide debug information about globals variables. The -provide details such as name, type and where the variable is defined.</p> +provide details such as name, type and where the variable is defined. All +global variables are collected by named metadata <tt>!llvm.dbg.gv</tt>.</p> </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_subprograms">Subprogram descriptors</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -432,30 +429,35 @@ provide details such as name, type and where the variable is defined.</p> i32, ;; Line number where defined metadata, ;; Reference to type descriptor i1, ;; True if the global is local to compile unit (static) - i1 ;; True if the global is defined in the compile unit (not extern) - i32 ;; Virtuality, e.g. dwarf::DW_VIRTUALITY__virtual - i32 ;; Index into a virtual function + i1, ;; True if the global is defined in the compile unit (not extern) + i32, ;; Virtuality, e.g. dwarf::DW_VIRTUALITY__virtual + i32, ;; Index into a virtual function metadata, ;; indicates which base type contains the vtable pointer for the ;; derived class - i1 ;; isArtificial - i1 ;; isOptimized - Function *;; Pointer to LLVM function + i1, ;; isArtificial + i1, ;; isOptimized + Function *,;; Pointer to LLVM function + metadata, ;; Lists function template parameters + metadata ;; Function declaration descriptor } </pre> </div> <p>These descriptors provide debug information about functions, methods and subprograms. They provide details such as name, return types and the source - location where the subprogram is defined.</p> + location where the subprogram is defined. + All subprogram descriptors are collected by a named metadata + <tt>!llvm.dbg.sp</tt>. +</p> </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_blocks">Block descriptors</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -463,7 +465,9 @@ provide details such as name, type and where the variable is defined.</p> i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block) metadata,;; Reference to context descriptor i32, ;; Line number - i32 ;; Column number + i32, ;; Column number + metadata,;; Reference to source file + i32 ;; Unique ID to identify blocks from a template function } </pre> </div> @@ -475,11 +479,11 @@ provide details such as name, type and where the variable is defined.</p> </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_basic_type">Basic type descriptors</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -527,11 +531,11 @@ DW_ATE_unsigned_char = 8 </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_derived_type">Derived type descriptors</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -544,7 +548,12 @@ DW_ATE_unsigned_char = 8 i64, ;; Size in bits i64, ;; Alignment in bits i64, ;; Offset in bits - metadata ;; Reference to type derived from + metadata, ;; Reference to type derived from + metadata, ;; (optional) Name of the Objective C property assoicated with + ;; Objective-C an ivar + metadata, ;; (optional) Name of the Objective C property getter selector. + metadata, ;; (optional) Name of the Objective C property setter selector. + i32 ;; (optional) Objective C property attributes. } </pre> </div> @@ -594,11 +603,11 @@ DW_TAG_restrict_type = 55 </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_composite_type">Composite type descriptors</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -644,7 +653,8 @@ DW_TAG_inheritance = 28 <p>The members of enumeration types (tag = <tt>DW_TAG_enumeration_type</tt>) are <a href="#format_enumeration">enumerator descriptors</a>, each representing - the definition of enumeration value for the set.</p> + the definition of enumeration value for the set. All enumeration type + descriptors are collected by named metadata <tt>!llvm.dbg.enum</tt>.</p> <p>The members of structure (tag = <tt>DW_TAG_structure_type</tt>) or union (tag = <tt>DW_TAG_union_type</tt>) types are any one of @@ -680,11 +690,11 @@ DW_TAG_inheritance = 28 </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_subrange">Subrange descriptors</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -700,16 +710,17 @@ DW_TAG_inheritance = 28 <a href="#format_composite_type">composite type</a>. The low value defines the lower bounds typically zero for C/C++. The high value is the upper bounds. Values are 64 bit. High - low + 1 is the size of the array. If low - == high the array will be unbounded.</p> + > high the array bounds are not included in generated debugging information. +</p> </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_enumeration">Enumerator descriptors</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -729,11 +740,11 @@ DW_TAG_inheritance = 28 </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_variables">Local variables</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -742,7 +753,8 @@ DW_TAG_inheritance = 28 metadata, ;; Context metadata, ;; Name metadata, ;; Reference to file where defined - i32, ;; Line number where defined + i32, ;; 24 bit - Line number where defined + ;; 8 bit - Argument number. 1 indicates 1st argument. metadata ;; Type descriptor } </pre> @@ -771,39 +783,39 @@ DW_TAG_return_variable = 258 </div> +</div> + <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="format_common_intrinsics">Debugger intrinsic functions</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>LLVM uses several intrinsic functions (name prefixed with "llvm.dbg") to provide debug information at various points in generated code.</p> -</div> - <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_common_declare">llvm.dbg.declare</a> -</div> +</h4> -<div class="doc_text"> +<div> <pre> void %<a href="#format_common_declare">llvm.dbg.declare</a>(metadata, metadata) </pre> <p>This intrinsic provides information about a local element (ex. variable.) The - first argument is metadata holding alloca for the variable.</tt>. The + first argument is metadata holding alloca for the variable. The second argument is metadata containing description of the variable. </p> </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="format_common_value">llvm.dbg.value</a> -</div> +</h4> -<div class="doc_text"> +<div> <pre> void %<a href="#format_common_value">llvm.dbg.value</a>(metadata, i64, metadata) </pre> @@ -815,12 +827,14 @@ DW_TAG_return_variable = 258 user source variable. </p> </div> +</div> + <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="format_common_lifetime">Object lifetimes and scoping</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>In many languages, the local variables in functions can have their lifetimes or scopes limited to a subset of a function. In the C family of languages, for example, variables are only live (readable and writable) within the @@ -978,13 +992,15 @@ call void @llvm.dbg.declare(metadata, metadata !12), !dbg !14 </div> +</div> + <!-- *********************************************************************** --> -<div class="doc_section"> +<h2> <a name="ccxx_frontend">C/C++ front-end specific debug information</a> -</div> +</h2> <!-- *********************************************************************** --> -<div class="doc_text"> +<div> <p>The C and C++ front-ends represent information about the program in a format that is effectively identical @@ -1005,14 +1021,12 @@ call void @llvm.dbg.declare(metadata, metadata !12), !dbg !14 <p>The following sections provide examples of various C/C++ constructs and the debug information that would best describe those constructs.</p> -</div> - <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="ccxx_compile_units">C/C++ source file information</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>Given the source files <tt>MySource.cpp</tt> and <tt>MyHeader.h</tt> located in the directory <tt>/Users/mine/sources</tt>, the following code:</p> @@ -1086,11 +1100,11 @@ using <tt>Instruction::getMetadata()</tt> and </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="ccxx_global_variable">C/C++ global variable information</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>Given an integer global variable declared as follows:</p> @@ -1156,11 +1170,11 @@ int MyGlobal = 100; </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="ccxx_subprogram">C/C++ function information</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>Given a function declared as follows:</p> @@ -1192,7 +1206,14 @@ int main(int argc, char *argv[]) { i32 1, ;; Line number metadata !4, ;; Type i1 false, ;; Is local - i1 true ;; Is definition + i1 true, ;; Is definition + i32 0, ;; Virtuality attribute, e.g. pure virtual function + i32 0, ;; Index into virtual table for C++ methods + i32 0, ;; Type that holds virtual table. + i32 0, ;; Flags + i1 false, ;; True if this function is optimized + Function *, ;; Pointer to llvm::Function + null ;; Function template parameters } ;; ;; Define the subprogram itself. @@ -1206,22 +1227,20 @@ define i32 @main(i32 %argc, i8** %argv) { </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="ccxx_basic_types">C/C++ basic types</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>The following are the basic type descriptors for C/C++ core types:</p> -</div> - <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="ccxx_basic_type_bool">bool</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -1243,11 +1262,11 @@ define i32 @main(i32 %argc, i8** %argv) { </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="ccxx_basic_char">char</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -1269,11 +1288,11 @@ define i32 @main(i32 %argc, i8** %argv) { </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="ccxx_basic_unsigned_char">unsigned char</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -1295,11 +1314,11 @@ define i32 @main(i32 %argc, i8** %argv) { </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="ccxx_basic_short">short</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -1321,11 +1340,11 @@ define i32 @main(i32 %argc, i8** %argv) { </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="ccxx_basic_unsigned_short">unsigned short</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -1347,11 +1366,11 @@ define i32 @main(i32 %argc, i8** %argv) { </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="ccxx_basic_int">int</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -1372,11 +1391,11 @@ define i32 @main(i32 %argc, i8** %argv) { </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="ccxx_basic_unsigned_int">unsigned int</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -1398,11 +1417,11 @@ define i32 @main(i32 %argc, i8** %argv) { </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="ccxx_basic_long_long">long long</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -1424,11 +1443,11 @@ define i32 @main(i32 %argc, i8** %argv) { </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="ccxx_basic_unsigned_long_long">unsigned long long</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -1450,11 +1469,11 @@ define i32 @main(i32 %argc, i8** %argv) { </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="ccxx_basic_float">float</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -1476,11 +1495,11 @@ define i32 @main(i32 %argc, i8** %argv) { </div> <!-- ======================================================================= --> -<div class="doc_subsubsection"> +<h4> <a name="ccxx_basic_double">double</a> -</div> +</h4> -<div class="doc_text"> +<div> <div class="doc_code"> <pre> @@ -1501,12 +1520,14 @@ define i32 @main(i32 %argc, i8** %argv) { </div> +</div> + <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="ccxx_derived_types">C/C++ derived types</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>Given the following as an example of C/C++ derived type:</p> @@ -1587,11 +1608,11 @@ typedef const int *IntPtr; </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="ccxx_composite_types">C/C++ struct/union types</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>Given the following as an example of C/C++ struct type:</p> @@ -1700,11 +1721,11 @@ struct Color { </div> <!-- ======================================================================= --> -<div class="doc_subsection"> +<h3> <a name="ccxx_enumeration_types">C/C++ enumeration types</a> -</div> +</h3> -<div class="doc_text"> +<div> <p>Given the following as an example of C/C++ enumeration type:</p> @@ -1765,6 +1786,8 @@ enum Trees { </div> +</div> + <!-- *********************************************************************** --> <hr> @@ -1775,8 +1798,8 @@ enum Trees { src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a> <a href="mailto:sabre@nondot.org">Chris Lattner</a><br> - <a href="http://llvm.org">LLVM Compiler Infrastructure</a><br> - Last modified: $Date: 2011-02-03 01:22:17 +0100 (Thu, 03 Feb 2011) $ + <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br> + Last modified: $Date: 2011-04-23 02:30:22 +0200 (Sat, 23 Apr 2011) $ </address> </body> |
