</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">
<li><a href="#debug_info_descriptors">Debug information descriptors</a>
<ul>
<li><a href="#format_compile_units">Compile unit descriptors</a></li>
+ <li><a href="#format_files">File descriptors</a></li>
<li><a href="#format_global_variables">Global variable descriptors</a></li>
<li><a href="#format_subprograms">Subprogram descriptors</a></li>
<li><a href="#format_blocks">Block descriptors</a></li>
</ul></li>
<li><a href="#format_common_intrinsics">Debugger intrinsic functions</a>
<ul>
- <li><a href="#format_common_stoppoint">llvm.dbg.stoppoint</a></li>
- <li><a href="#format_common_func_start">llvm.dbg.func.start</a></li>
- <li><a href="#format_common_region_start">llvm.dbg.region.start</a></li>
- <li><a href="#format_common_region_end">llvm.dbg.region.end</a></li>
<li><a href="#format_common_declare">llvm.dbg.declare</a></li>
+ <li><a href="#format_common_value">llvm.dbg.value</a></li>
</ul></li>
- <li><a href="#format_common_stoppoints">Representing stopping points in the
- source program</a></li>
</ol></li>
+ <li><a href="#format_common_lifetime">Object lifetimes and scoping</a></li>
<li><a href="#ccxx_frontend">C/C++ front-end specific debug information</a>
<ol>
<li><a href="#ccxx_compile_units">C/C++ source file information</a></li>
<!-- *********************************************************************** -->
-<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
that the LLVM debug information</a> takes, which is useful for those
interested in creating front-ends or dealing directly with the information.
Further, this document provides specific examples of what debug information
- for C/C++.</p>
-
-</div>
+ for C/C++ looks like.</p>
<!-- ======================================================================= -->
-<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.
<p>The approach used by the LLVM implementation is to use a small set
of <a href="#format_common_intrinsics">intrinsic functions</a> to define a
mapping between LLVM program objects and the source-level objects. The
- description of the source-level program is maintained in LLVM global
-
variables in an <a href="#ccxx_frontend">implementation-defined format</a>
+ description of the source-level program is maintained in LLVM metadata
+ in an <a href="#ccxx_frontend">implementation-defined format</a>
(the C/C++ front-end currently uses working draft 7 of
the <a href="http://www.eagercon.com/dwarf/dwarf3std.htm">DWARF 3
standard</a>).</p>
</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
an LLVM user a relationship between generated code and the original program
source code.</p>
-<p>Currently, debug information is consumed by the DwarfWriter to produce dwarf
+<p>Currently, debug information is consumed by DwarfDebug to produce dwarf
information used by the gdb debugger. Other targets could use the same
information to produce stabs or other debug forms.</p>
</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
as setting program variables, or calling functions that have been
deleted.</li>
- <li>LLVM optimizations gracefully interact with debugging information. If
- they are not aware of debug information, they are automatically disabled
- as necessary in the cases that would invalidate the debug info. This
- retains the LLVM features, making it easy to write new
- transformations.</li>
-
<li>As desired, LLVM optimizations can be upgraded to be aware of the LLVM
debugging information, allowing them to update the debugging information
as they perform aggressive optimizations. This means that, with effort,
the LLVM optimizers could optimize debug code just as well as non-debug
code.</li>
- <li>LLVM debug information does not prevent many important optimizations from
+ <li>LLVM debug information does not prevent optimizations from
happening (for example inlining, basic block reordering/merging/cleanup,
- tail duplication, etc), further reducing the amount of the compiler that
- eventually is "aware" of debugging information.</li>
+ tail duplication, etc).</li>
<li>LLVM debug information is automatically optimized along with the rest of
the program, using existing facilities. For example, duplicate
</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
necessarily having to know anything about debugging information. In
- particular, the global constant merging pass automatically eliminates
- duplicated debugging information (often caused by header files), the global
- dead code elimination pass automatically deletes debugging information for a
- function if it decides to delete the function, and the linker eliminates
- debug information when it merges <tt>linkonce</tt> functions.</p>
+ particular, the use of metadata avoids duplicated debugging information from
+ the beginning, and the global dead code elimination pass automatically
+ deletes debugging information for a function if it decides to delete the
+ function. </p>
<p>To do this, most of the debugging information (descriptors for types,
variables, functions, source files, etc) is inserted by the language
- front-end in the form of LLVM global variables. These LLVM global variables
- are no different from any other global variables, except that they have a web
- of LLVM intrinsic functions that point to them. If the last references to a
- particular piece of debugging information are deleted (for example, by the
- <tt>-globaldce</tt> pass), the extraneous debug information will
- automatically become dead and be removed by the optimizer.</p>
+ front-end in the form of LLVM metadata. </p>
<p>Debug information is designed to be agnostic about the target debugger and
debugging information representation (e.g. DWARF/Stabs/etc). It uses a
- generic machine debug information pass to decode the information that
- represents variables, types, functions, namespaces, etc: this allows for
- arbitrary source-language semantics and type-systems to be used, as long as
- there is a module written for the target debugger to interpret the
- information. In addition, debug global variables are declared in
- the <tt>"llvm.metadata"</tt> section. All values declared in this section
- are stripped away after target debug information is constructed and before
- the program object is emitted.</p>
+ generic pass to decode the information that represents variables, types,
+ functions, namespaces, etc: this allows for arbitrary source-language
+ semantics and type-systems to be used, as long as there is a module
+ written for the target debugger to interpret the information. </p>
<p>To provide basic functionality, the LLVM debugger does have to make some
assumptions about the source-level language being debugged, though it keeps
these to a minimum. The only common features that the LLVM debugger assumes
- exist are <a href="#format_compile_units">source files</a>,
+ exist are <a href="#format_files">source files</a>,
and <a href="#format_global_variables">program objects</a>. These abstract
objects are used by a debugger to form stack traces, show information about
local variables, etc.</p>
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 global variables. The
- constant value of each of these globals is one of a limited set of
- structures, known as debug descriptors.</p>
+ provides a specification for well formed debug descriptors. </p>
<p>Consumers of LLVM debug information expect the descriptors for program
objects to start in a canonical format, but the descriptors can include
way. Also, all debugging information objects start with a tag to indicate
what type of object it is. The source-language is allowed to define its own
objects, by using unreserved tag numbers. We recommend using with tags in
- the range 0x1000 thru 0x2000 (there is a defined enum DW_TAG_user_base =
+ the range 0x1000 through 0x2000 (there is a defined enum DW_TAG_user_base =
0x1000.)</p>
-<p>The fields of debug descriptors used internally by LLVM (MachineModuleInfo)
- are restricted to only the simple data types <tt>int</tt>, <tt>uint</tt>,
- <tt>bool</tt>, <tt>float</tt>, <tt>double</tt>, <tt>i8*</tt> and
- <tt>{ }*</tt>. References to arbitrary values are handled using a
- <tt>{ }*</tt> and a cast to <tt>{ }*</tt> expression; typically
- references to other field descriptors, arrays of descriptors or global
- variables.</p>
+<p>The fields of debug descriptors used internally by LLVM
+ are restricted to only the simple data types <tt>i32</tt>, <tt>i1</tt>,
+ <tt>float</tt>, <tt>double</tt>, <tt>mdstring</tt> and <tt>mdnode</tt>. </p>
<div class="doc_code">
<pre>
-%llvm.dbg.object.type = type {
- uint, ;; A tag
+!1 = metadata !{
+ i32, ;; A tag
...
}
</pre>
</div>
<p><a name="LLVMDebugVersion">The first field of a descriptor is always an
- <tt>uint</tt> containing a tag value identifying the content of the
+ <tt>i32</tt> containing a tag value identifying the content of the
descriptor. The remaining fields are specific to the descriptor. The values
of tags are loosely bound to the tag values of DWARF information entries.
However, that does not restrict the use of the information supplied to DWARF
targets. To facilitate versioning of debug information, the tag is augmented
- with the current debug version (LLVMDebugVersion = 4 << 16 or 0x40000 or
- 262144.)</a></p>
+ with the current debug version (LLVMDebugVersion = 8 << 16 or
+ 0x80000 or 524288.)</a></p>
<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>
-%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = type {
- i32, ;; Tag = 17 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_compile_unit)
- { }*, ;; Compile unit anchor = cast = (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_units</a> to { }*)
- i32, ;; DWARF language identifier (ex. DW_LANG_C89)
- i8*, ;; Source file name
- i8*, ;; Source file directory (includes trailing slash)
- i8* ;; Producer (ex. "4.0.1 LLVM (LLVM research group)")
- i1, ;; True if this is a main compile unit.
- i1, ;; True if this is optimized.
- i8*, ;; Flags
- i32 ;; Runtime version
+!0 = metadata !{
+ i32, ;; Tag = 17 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
+ ;; (DW_TAG_compile_unit)
+ i32, ;; Unused field.
+ i32, ;; DWARF language identifier (ex. DW_LANG_C89)
+ metadata, ;; Source file name
+ metadata, ;; Source file directory (includes trailing slash)
+ metadata ;; Producer (ex. "4.0.1 LLVM (LLVM research group)")
+ i1, ;; True if this is a main compile unit.
+ i1, ;; True if this is optimized.
+ metadata, ;; Flags
+ i32 ;; Runtime version
+ metadata ;; List of enums types
+ metadata ;; List of retained types
+ metadata ;; List of subprograms
+ metadata ;; List of global variables
}
</pre>
</div>
that produced it.</p>
<p>Compile unit descriptors provide the root context for objects declared in a
- specific source file. Global variables and top level functions would be
- defined using this context. Compile unit descriptors also provide context
- for source line correspondence.</p>
+ specific compilation unit. File descriptors are defined using this context.
+ These descriptors are collected by a named metadata
+ <tt>!llvm.dbg.cu</tt>. Compile unit descriptor keeps track of subprograms,
+ global variables and type information.
+
+</div>
+
+<!-- ======================================================================= -->
+<h4>
+ <a name="format_files">File descriptors</a>
+</h4>
-<p>Each input file is encoded as a separate compile unit in LLVM debugging
- information output. However, many target specific tool chains prefer to
- encode only one compile unit in an object file. In this situation, the LLVM
- code generator will include debugging information entities in the compile
- unit that is marked as main compile unit. The code generator accepts maximum
- one main compile unit per module. If a module does not contain any main
- compile unit then the code generator will emit multiple compile units in the
- output object file.</p>
+<div>
+
+<div class="doc_code">
+<pre>
+!0 = metadata !{
+ i32, ;; Tag = 41 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
+ ;; (DW_TAG_file_type)
+ metadata, ;; Source file name
+ metadata, ;; Source file directory (includes trailing slash)
+ metadata ;; Unused
+}
+</pre>
+</div>
+
+<p>These descriptors contain information for a file. Global variables and top
+ level functions would be defined using this context.k File descriptors also
+ provide context for source line correspondence. </p>
+
+<p>Each input file is encoded as a separate file descriptor in LLVM debugging
+ information output. </p>
</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>
-%<a href="#format_global_variables">llvm.dbg.global_variable.type</a> = type {
- i32, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_variable)
- { }*, ;; Global variable anchor = cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_global_variables">llvm.dbg.global_variables</a> to { }*),
- { }*, ;; Reference to context descriptor
- i8*, ;; Name
- i8*, ;; Display name (fully qualified C++ name)
- i8*, ;; MIPS linkage name (for C++)
- { }*, ;; Reference to compile unit where defined
- i32, ;; Line number where defined
- { }*, ;; 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)
- { }* ;; Reference to the global variable
+!1 = metadata !{
+ i32, ;; Tag = 52 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
+ ;; (DW_TAG_variable)
+ i32, ;; Unused field.
+ metadata, ;; Reference to context descriptor
+ metadata, ;; Name
+ metadata, ;; Display name (fully qualified C++ name)
+ metadata, ;; MIPS linkage name (for C++)
+ metadata, ;; Reference to file where defined
+ 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)
+ {}* ;; Reference to the global variable
}
</pre>
</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>
-%<a href="#format_subprograms">llvm.dbg.subprogram.type</a> = type {
- i32, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subprogram)
- { }*, ;; Subprogram anchor = cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_subprograms">llvm.dbg.subprograms</a> to { }*),
- { }*, ;; Reference to context descriptor
- i8*, ;; Name
- i8*, ;; Display name (fully qualified C++ name)
- i8*, ;; MIPS linkage name (for C++)
- { }*, ;; Reference to compile unit where defined
- i32, ;; Line number where defined
- { }*, ;; 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)
+!2 = metadata !{
+ i32, ;; Tag = 46 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
+ ;; (DW_TAG_subprogram)
+ i32, ;; Unused field.
+ metadata, ;; Reference to context descriptor
+ metadata, ;; Name
+ metadata, ;; Display name (fully qualified C++ name)
+ metadata, ;; MIPS linkage name (for C++)
+ metadata, ;; Reference to file where defined
+ 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
+ metadata, ;; indicates which base type contains the vtable pointer for the
+ ;; derived class
+ i1, ;; isArtificial
+ i1, ;; isOptimized
+ Function *,;; Pointer to LLVM function
+ metadata, ;; Lists function template parameters
+ metadata ;; Function declaration descriptor
+ metadata ;; List of function variables
}
</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>
+</h4>
+
+<div>
+
+<div class="doc_code">
+<pre>
+!3 = metadata !{
+ i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
+ metadata,;; Reference to context descriptor
+ i32, ;; Line number
+ i32, ;; Column number
+ metadata,;; Reference to source file
+ i32 ;; Unique ID to identify blocks from a template function
+}
+</pre>
</div>
-<div class="doc_text">
+<p>This descriptor provides debug information about nested blocks within a
+ subprogram. The line number and column numbers are used to dinstinguish
+ two lexical blocks at same depth. </p>
<div class="doc_code">
<pre>
-%<a href="#format_blocks">llvm.dbg.block</a> = type {
- i32, ;; Tag = 13 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
- { }* ;; Reference to context descriptor
+!3 = metadata !{
+ i32, ;; Tag = 11 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_lexical_block)
+ metadata ;; Reference to the scope we're annotating with a file change
+ metadata,;; Reference to the file the scope is enclosed in.
}
</pre>
</div>
-<p>These descriptors provide debug information about nested blocks within a
- subprogram. The array of member descriptors is used to define local
- variables and deeper nested blocks.</p>
+<p>This descriptor provides a wrapper around a lexical scope to handle file
+ changes in the middle of a lexical block.</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>
-%<a href="#format_basic_type">llvm.dbg.basictype.type</a> = type {
- i32, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_base_type)
- { }*, ;; Reference to context (typically a compile unit)
- i8*, ;; Name (may be "" for anonymous types)
- { }*, ;; Reference to compile unit where defined (may be NULL)
- i32, ;; Line number where defined (may be 0)
- i64, ;; Size in bits
- i64, ;; Alignment in bits
- i64, ;; Offset in bits
- i32, ;; Flags
- i32 ;; DWARF type encoding
+!4 = metadata !{
+ i32, ;; Tag = 36 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
+ ;; (DW_TAG_base_type)
+ metadata, ;; Reference to context
+ metadata, ;; Name (may be "" for anonymous types)
+ metadata, ;; Reference to file where defined (may be NULL)
+ i32, ;; Line number where defined (may be 0)
+ i64, ;; Size in bits
+ i64, ;; Alignment in bits
+ i64, ;; Offset in bits
+ i32, ;; Flags
+ i32 ;; DWARF type encoding
}
</pre>
</div>
<p>These descriptors define primitive types used in the code. Example int, bool
and float. The context provides the scope of the type, which is usually the
- top level. Since basic types are not usually user defined the compile unit
+ top level. Since basic types are not usually user defined the context
and line number can be left as NULL and 0. The size, alignment and offset
are expressed in bits and can be 64 bit values. The alignment is used to
round the offset when embedded in a
</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>
-%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> = type {
- i32, ;; Tag (see below)
- { }*, ;; Reference to context
- i8*, ;; Name (may be "" for anonymous types)
- { }*, ;; Reference to compile unit where defined (may be NULL)
- i32, ;; Line number where defined (may be 0)
- i32, ;; Size in bits
- i32, ;; Alignment in bits
- i32, ;; Offset in bits
- { }* ;; Reference to type derived from
+!5 = metadata !{
+ i32, ;; Tag (see below)
+ metadata, ;; Reference to context
+ metadata, ;; Name (may be "" for anonymous types)
+ metadata, ;; Reference to file where defined (may be NULL)
+ i32, ;; Line number where defined (may be 0)
+ i64, ;; Size in bits
+ i64, ;; Alignment in bits
+ i64, ;; Offset in bits
+ 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>
the <a href="#format_derived_type">derived type</a>. </p>
<p><a href="#format_derived_type">Derived type</a> location can be determined
- from the compile unit and line number. The size, alignment and offset are
+ from the context and line number. The size, alignment and offset are
expressed in bits and can be 64 bit values. The alignment is used to round
the offset when embedded in a <a href="#format_composite_type">composite
type</a> (example to keep float doubles on 64 bit boundaries.) The offset is
the bit offset if embedded in a <a href="#format_composite_type">composite
type</a>.</p>
-<p>Note that the <tt>void *</tt> type is expressed as a
- <tt>llvm.dbg.derivedtype.type</tt> with tag of <tt>DW_TAG_pointer_type</tt>
- and <tt>NULL</tt> derived type.</p>
+<p>Note that the <tt>void *</tt> type is expressed as a type derived from NULL.
+</p>
</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>
-%<a href="#format_composite_type">llvm.dbg.compositetype.type</a> = type {
- i32, ;; Tag (see below)
- { }*, ;; Reference to context
- i8*, ;; Name (may be "" for anonymous types)
- { }*, ;; Reference to compile unit where defined (may be NULL)
- i32, ;; Line number where defined (may be 0)
- i64, ;; Size in bits
- i64, ;; Alignment in bits
- i64, ;; Offset in bits
- i32, ;; Flags
- { }*, ;; Reference to type derived from
- { }*, ;; Reference to array of member descriptors
- i32 ;; Runtime languages
+!6 = metadata !{
+ i32, ;; Tag (see below)
+ metadata, ;; Reference to context
+ metadata, ;; Name (may be "" for anonymous types)
+ metadata, ;; Reference to file where defined (may be NULL)
+ i32, ;; Line number where defined (may be 0)
+ i64, ;; Size in bits
+ i64, ;; Alignment in bits
+ i64, ;; Offset in bits
+ i32, ;; Flags
+ metadata, ;; Reference to type derived from
+ metadata, ;; Reference to array of member descriptors
+ i32 ;; Runtime languages
}
</pre>
</div>
<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
the formal arguments to the subroutine.</p>
<p><a href="#format_composite_type">Composite type</a> location can be
- determined from the compile unit and line number. The size, alignment and
+ determined from the context and line number. The size, alignment and
offset are expressed in bits and can be 64 bit values. The alignment is used
to round the offset when embedded in
a <a href="#format_composite_type">composite type</a> (as an example, to keep
</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>
-%<a href="#format_subrange">llvm.dbg.subrange.type</a> = type {
+!42 = metadata !{
i32, ;; Tag = 33 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_subrange_type)
i64, ;; Low value
i64 ;; High value
<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>
-%<a href="#format_enumeration">llvm.dbg.enumerator.type</a> = type {
- i32, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a> (DW_TAG_enumerator)
- i8*, ;; Name
- i64 ;; Value
+!6 = metadata !{
+ i32, ;; Tag = 40 + <a href="#LLVMDebugVersion">LLVMDebugVersion</a>
+ ;; (DW_TAG_enumerator)
+ metadata, ;; Name
+ i64 ;; Value
}
</pre>
</div>
</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>
-%<a href="#format_variables">llvm.dbg.variable.type</a> = type {
- i32, ;; Tag (see below)
- { }*, ;; Context
- i8*, ;; Name
- { }*, ;; Reference to compile unit where defined
- i32, ;; Line number where defined
- { }* ;; Type descriptor
+!7 = metadata !{
+ i32, ;; Tag (see below)
+ metadata, ;; Context
+ metadata, ;; Name
+ metadata, ;; Reference to file where defined
+ i32, ;; 24 bit - Line number where defined
+ ;; 8 bit - Argument number. 1 indicates 1st argument.
+ metadata, ;; Type descriptor
+ i32, ;; flags
+ metadata ;; (optional) Reference to inline location
}
</pre>
</div>
has no source correspondent.</p>
<p>The context is either the subprogram or block where the variable is defined.
- Name the source variable name. Compile unit and line indicate where the
+ Name the source variable name. Context and line indicate where the
variable was defined. Type descriptor defines the declared type of the
variable.</p>
</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">
- <a name="format_common_stoppoint">llvm.dbg.stoppoint</a>
-</div>
+<h4>
+ <a name="format_common_declare">llvm.dbg.declare</a>
+</h4>
-<div class="doc_text">
+<div>
<pre>
- void %<a href="#format_common_stoppoint">llvm.dbg.stoppoint</a>( uint, uint, { }* )
+ void %<a href="#format_common_declare">llvm.dbg.declare</a>(metadata, metadata)
</pre>
-<p>This intrinsic is used to provide correspondence between the source file and
- the generated code. The first argument is the line number (base 1), second
- argument is the column number (0 if unknown) and the third argument the
- source <tt>%<a href="#format_compile_units">llvm.dbg.compile_unit</a>*</tt>
- cast to a <tt>{ }*</tt>. Code following a call to this intrinsic will
- have been defined in close proximity of the line, column and file. This
- information holds until the next call
- to <tt>%<a href="#format_common_stoppoint">lvm.dbg.stoppoint</a></tt>.</p>
-
+<p>This intrinsic provides information about a local element (ex. variable.) 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">
- <a name="format_common_func_start">llvm.dbg.func.start</a>
-</div>
+<h4>
+ <a name="format_common_value">llvm.dbg.value</a>
+</h4>
-<div class="doc_text">
+<div>
<pre>
- void %<a href="#format_common_func_start">llvm.dbg.func.start</a>( { }* )
+ void %<a href="#format_common_value">llvm.dbg.value</a>(metadata, i64, metadata)
</pre>
-<p>This intrinsic is used to link the debug information
- in <tt>%<a href="#format_subprograms">llvm.dbg.subprogram</a></tt> to the
- function. It defines the beginning of the function's declarative region
- (scope). It also implies a call to
- %<tt><a href="#format_common_stoppoint">llvm.dbg.stoppoint</a></tt> which
- defines a source line "stop point". The intrinsic should be called early in
- the function after the all the alloca instructions. It should be paired off
- with a closing
- <tt>%<a href="#format_common_region_end">llvm.dbg.region.end</a></tt>.
- The function's single argument is
- the <tt>%<a href="#format_subprograms">llvm.dbg.subprogram.type</a></tt>.</p>
-
+<p>This intrinsic provides information when a user source variable is set to a
+ new value. The first argument is the new value (wrapped as metadata). The
+ second argument is the offset in the user source variable where the new value
+ is written. The third argument is metadata containing description of the
+ user source variable. </p>
</div>
-<!-- ======================================================================= -->
-<div class="doc_subsubsection">
- <a name="format_common_region_start">llvm.dbg.region.start</a>
</div>
-<div class="doc_text">
-<pre>
- void %<a href="#format_common_region_start">llvm.dbg.region.start</a>( { }* )
-</pre>
+<!-- ======================================================================= -->
+<h3>
+ <a name="format_common_lifetime">Object lifetimes and scoping</a>
+</h3>
-<p>This intrinsic is used to define the beginning of a declarative scope (ex.
- block) for local language elements. It should be paired off with a closing
- <tt>%<a href="#format_common_region_end">llvm.dbg.region.end</a></tt>. The
- function's single argument is
- the <tt>%<a href="#format_blocks">llvm.dbg.block</a></tt> which is
- starting.</p>
+<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
+ source block that they are defined in. In functional languages, values are
+ only readable after they have been defined. Though this is a very obvious
+ concept, it is non-trivial to model in LLVM, because it has no notion of
+ scoping in this sense, and does not want to be tied to a language's scoping
+ rules.</p>
+<p>In order to handle this, the LLVM debug format uses the metadata attached to
+ llvm instructions to encode line number and scoping information. Consider
+ the following C fragment, for example:</p>
+<div class="doc_code">
+<pre>
+1. void foo() {
+2. int X = 21;
+3. int Y = 22;
+4. {
+5. int Z = 23;
+6. Z = X;
+7. }
+8. X = Y;
+9. }
+</pre>
</div>
-<!-- ======================================================================= -->
-<div class="doc_subsubsection">
- <a name="format_common_region_end">llvm.dbg.region.end</a>
-</div>
+<p>Compiled to LLVM, this function would be represented like this:</p>
-<div class="doc_text">
+<div class="doc_code">
<pre>
- void %<a href="#format_common_region_end">llvm.dbg.region.end</a>( { }* )
-</pre>
-
-<p>This intrinsic is used to define the end of a declarative scope (ex. block)
- for local language elements. It should be paired off with an
- opening <tt>%<a href="#format_common_region_start">llvm.dbg.region.start</a></tt>
- or <tt>%<a href="#format_common_func_start">llvm.dbg.func.start</a></tt>.
- The function's single argument is either
- the <tt>%<a href="#format_blocks">llvm.dbg.block</a></tt> or
- the <tt>%<a href="#format_subprograms">llvm.dbg.subprogram.type</a></tt>
- which is ending.</p>
+define void @foo() nounwind ssp {
+entry:
+ %X = alloca i32, align 4 ; <i32*> [#uses=4]
+ %Y = alloca i32, align 4 ; <i32*> [#uses=4]
+ %Z = alloca i32, align 4 ; <i32*> [#uses=3]
+ %0 = bitcast i32* %X to {}* ; <{}*> [#uses=1]
+ call void @llvm.dbg.declare(metadata !{i32 * %X}, metadata !0), !dbg !7
+ store i32 21, i32* %X, !dbg !8
+ %1 = bitcast i32* %Y to {}* ; <{}*> [#uses=1]
+ call void @llvm.dbg.declare(metadata !{i32 * %Y}, metadata !9), !dbg !10
+ store i32 22, i32* %Y, !dbg !11
+ %2 = bitcast i32* %Z to {}* ; <{}*> [#uses=1]
+ call void @llvm.dbg.declare(metadata !{i32 * %Z}, metadata !12), !dbg !14
+ store i32 23, i32* %Z, !dbg !15
+ %tmp = load i32* %X, !dbg !16 ; <i32> [#uses=1]
+ %tmp1 = load i32* %Y, !dbg !16 ; <i32> [#uses=1]
+ %add = add nsw i32 %tmp, %tmp1, !dbg !16 ; <i32> [#uses=1]
+ store i32 %add, i32* %Z, !dbg !16
+ %tmp2 = load i32* %Y, !dbg !17 ; <i32> [#uses=1]
+ store i32 %tmp2, i32* %X, !dbg !17
+ ret void, !dbg !18
+}
+declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
+
+!0 = metadata !{i32 459008, metadata !1, metadata !"X",
+ metadata !3, i32 2, metadata !6}; [ DW_TAG_auto_variable ]
+!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
+!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo", metadata !"foo",
+ metadata !"foo", metadata !3, i32 1, metadata !4,
+ i1 false, i1 true}; [DW_TAG_subprogram ]
+!3 = metadata !{i32 458769, i32 0, i32 12, metadata !"foo.c",
+ metadata !"/private/tmp", metadata !"clang 1.1", i1 true,
+ i1 false, metadata !"", i32 0}; [DW_TAG_compile_unit ]
+!4 = metadata !{i32 458773, metadata !3, metadata !"", null, i32 0, i64 0, i64 0,
+ i64 0, i32 0, null, metadata !5, i32 0}; [DW_TAG_subroutine_type ]
+!5 = metadata !{null}
+!6 = metadata !{i32 458788, metadata !3, metadata !"int", metadata !3, i32 0,
+ i64 32, i64 32, i64 0, i32 0, i32 5}; [DW_TAG_base_type ]
+!7 = metadata !{i32 2, i32 7, metadata !1, null}
+!8 = metadata !{i32 2, i32 3, metadata !1, null}
+!9 = metadata !{i32 459008, metadata !1, metadata !"Y", metadata !3, i32 3,
+ metadata !6}; [ DW_TAG_auto_variable ]
+!10 = metadata !{i32 3, i32 7, metadata !1, null}
+!11 = metadata !{i32 3, i32 3, metadata !1, null}
+!12 = metadata !{i32 459008, metadata !13, metadata !"Z", metadata !3, i32 5,
+ metadata !6}; [ DW_TAG_auto_variable ]
+!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
+!14 = metadata !{i32 5, i32 9, metadata !13, null}
+!15 = metadata !{i32 5, i32 5, metadata !13, null}
+!16 = metadata !{i32 6, i32 5, metadata !13, null}
+!17 = metadata !{i32 8, i32 3, metadata !1, null}
+!18 = metadata !{i32 9, i32 1, metadata !2, null}
+</pre>
</div>
-<!-- ======================================================================= -->
-<div class="doc_subsubsection">
- <a name="format_common_declare">llvm.dbg.declare</a>
-</div>
+<p>This example illustrates a few important details about LLVM debugging
+ information. In particular, it shows how the <tt>llvm.dbg.declare</tt>
+ intrinsic and location information, which are attached to an instruction,
+ are applied together to allow a debugger to analyze the relationship between
+ statements, variable definitions, and the code used to implement the
+ function.</p>
-<div class="doc_text">
+<div class="doc_code">
<pre>
- void %<a href="#format_common_declare">llvm.dbg.declare</a>( { } *, { }* )
+call void @llvm.dbg.declare(metadata, metadata !0), !dbg !7
</pre>
-
-<p>This intrinsic provides information about a local element (ex. variable.) The
- first argument is the alloca for the variable, cast to a <tt>{ }*</tt>. The
- second argument is
- the <tt>%<a href="#format_variables">llvm.dbg.variable</a></tt> containing
- the description of the variable, also cast to a <tt>{ }*</tt>.</p>
-
</div>
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="format_common_stoppoints">
- Representing stopping points in the source program
- </a>
-</div>
-
-<div class="doc_text">
-
-<p>LLVM debugger "stop points" are a key part of the debugging representation
- that allows the LLVM to maintain simple semantics
- for <a href="#debugopt">debugging optimized code</a>. The basic idea is that
- the front-end inserts calls to
- the <a href="#format_common_stoppoint">%<tt>llvm.dbg.stoppoint</tt></a>
- intrinsic function at every point in the program where a debugger should be
- able to inspect the program (these correspond to places a debugger stops when
- you "<tt>step</tt>" through it). The front-end can choose to place these as
- fine-grained as it would like (for example, before every subexpression
- evaluated), but it is recommended to only put them after every source
- statement that includes executable code.</p>
-
-<p>Using calls to this intrinsic function to demark legal points for the
- debugger to inspect the program automatically disables any optimizations that
- could potentially confuse debugging information. To
- non-debug-information-aware transformations, these calls simply look like
- calls to an external function, which they must assume to do anything
- (including reading or writing to any part of reachable memory). On the other
- hand, it does not impact many optimizations, such as code motion of
- non-trapping instructions, nor does it impact optimization of subexpressions,
- code duplication transformations, or basic-block reordering
- transformations.</p>
-
-</div>
+<p>The first intrinsic
+ <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
+ encodes debugging information for the variable <tt>X</tt>. The metadata
+ <tt>!dbg !7</tt> attached to the intrinsic provides scope information for the
+ variable <tt>X</tt>.</p>
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="format_common_lifetime">Object lifetimes and scoping</a>
+<div class="doc_code">
+<pre>
+!7 = metadata !{i32 2, i32 7, metadata !1, null}
+!1 = metadata !{i32 458763, metadata !2}; [DW_TAG_lexical_block ]
+!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"foo",
+ metadata !"foo", metadata !"foo", metadata !3, i32 1,
+ metadata !4, i1 false, i1 true}; [DW_TAG_subprogram ]
+</pre>
</div>
-<div class="doc_text">
-<p>In many languages, the local variables in functions can have their lifetime
- or scope limited to a subset of a function. In the C family of languages,
- for example, variables are only live (readable and writable) within the
- source block that they are defined in. In functional languages, values are
- only readable after they have been defined. Though this is a very obvious
- concept, it is also non-trivial to model in LLVM, because it has no notion of
- scoping in this sense, and does not want to be tied to a language's scoping
- rules.</p>
+<p>Here <tt>!7</tt> is metadata providing location information. It has four
+ fields: line number, column number, scope, and original scope. The original
+ scope represents inline location if this instruction is inlined inside a
+ caller, and is null otherwise. In this example, scope is encoded by
+ <tt>!1</tt>. <tt>!1</tt> represents a lexical block inside the scope
+ <tt>!2</tt>, where <tt>!2</tt> is a
+ <a href="#format_subprograms">subprogram descriptor</a>. This way the
+ location information attached to the intrinsics indicates that the
+ variable <tt>X</tt> is declared at line number 2 at a function level scope in
+ function <tt>foo</tt>.</p>
-<p>In order to handle this, the LLVM debug format uses the notion of "regions"
- of a function, delineated by calls to intrinsic functions. These intrinsic
- functions define new regions of the program and indicate when the region
- lifetime expires. Consider the following C fragment, for example:</p>
+<p>Now lets take another example.</p>
<div class="doc_code">
<pre>
-1. void foo() {
-2. int X = ...;
-3. int Y = ...;
-4. {
-5. int Z = ...;
-6. ...
-7. }
-8. ...
-9. }
+call void @llvm.dbg.declare(metadata, metadata !12), !dbg !14
</pre>
</div>
-<p>Compiled to LLVM, this function would be represented like this:</p>
+<p>The second intrinsic
+ <tt>%<a href="#format_common_declare">llvm.dbg.declare</a></tt>
+ encodes debugging information for variable <tt>Z</tt>. The metadata
+ <tt>!dbg !14</tt> attached to the intrinsic provides scope information for
+ the variable <tt>Z</tt>.</p>
<div class="doc_code">
<pre>
-void %foo() {
-entry:
- %X = alloca int
- %Y = alloca int
- %Z = alloca int
-
- ...
-
- 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 )
-
- 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 )
-
- call void @<a href="#format_common_declare">llvm.dbg.declare</a>({}* %X, ...)
- call void @<a href="#format_common_declare">llvm.dbg.declare</a>({}* %Y, ...)
-
- <i>;; Evaluate expression on line 2, assigning to X.</i>
-
- 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 )
-
- <i>;; Evaluate expression on line 3, assigning to Y.</i>
-
- call void @<a href="#format_common_stoppoint">llvm.region.start</a>()
- 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 )
- call void @<a href="#format_common_declare">llvm.dbg.declare</a>({}* %X, ...)
-
- <i>;; Evaluate expression on line 5, assigning to Z.</i>
-
- 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 )
- call void @<a href="#format_common_region_end">llvm.region.end</a>()
-
- 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 )
-
- call void @<a href="#format_common_region_end">llvm.region.end</a>()
-
- ret void
-}
+!13 = metadata !{i32 458763, metadata !1}; [DW_TAG_lexical_block ]
+!14 = metadata !{i32 5, i32 9, metadata !13, null}
</pre>
</div>
-<p>This example illustrates a few important details about the LLVM debugging
- information. In particular, it shows how the various intrinsics are applied
- together to allow a debugger to analyze the relationship between statements,
- variable definitions, and the code used to implement the function.</p>
-
-<p>The first
- intrinsic <tt>%<a href="#format_common_func_start">llvm.dbg.func.start</a></tt>
- provides a link with the <a href="#format_subprograms">subprogram
- descriptor</a> containing the details of this function. This call also
- defines the beginning of the function region, bounded by
- the <tt>%<a href="#format_common_region_end">llvm.region.end</a></tt> at the
- end of the function. This region is used to bracket the lifetime of
- variables declared within. For a function, this outer region defines a new
- stack frame whose lifetime ends when the region is ended.</p>
-
-<p>It is possible to define inner regions for short term variables by using the
- %<a href="#format_common_stoppoint"><tt>llvm.region.start</tt></a>
- and <a href="#format_common_region_end"><tt>%llvm.region.end</tt></a> to
- bound a region. The inner region in this example would be for the block
- containing the declaration of Z.</p>
-
-<p>Using regions to represent the boundaries of source-level functions allow
- LLVM interprocedural optimizations to arbitrarily modify LLVM functions
- without having to worry about breaking mapping information between the LLVM
- code and the and source-level program. In particular, the inliner requires
- no modification to support inlining with debugging information: there is no
- explicit correlation drawn between LLVM functions and their source-level
- counterparts (note however, that if the inliner inlines all instances of a
- non-strong-linkage function into its caller that it will not be possible for
- the user to manually invoke the inlined function from a debugger).</p>
-
-<p>Once the function has been defined,
- the <a href="#format_common_stoppoint"><tt>stopping point</tt></a>
- corresponding to line #2 (column #2) of the function is encountered. At this
- point in the function, <b>no</b> local variables are live. As lines 2 and 3
- of the example are executed, their variable definitions are introduced into
- the program using
- %<a href="#format_common_declare"><tt>llvm.dbg.declare</tt></a>, without the
- need to specify a new region. These variables do not require new regions to
- be introduced because they go out of scope at the same point in the program:
- line 9.</p>
-
-<p>In contrast, the <tt>Z</tt> variable goes out of scope at a different time,
- on line 7. For this reason, it is defined within the inner region, which
- kills the availability of <tt>Z</tt> before the code for line 8 is executed.
- In this way, regions can support arbitrary source-language scoping rules, as
- long as they can only be nested (ie, one scope cannot partially overlap with
- a part of another scope).</p>
-
-<p>It is worth noting that this scoping mechanism is used to control scoping of
- all declarations, not just variable declarations. For example, the scope of
- a C++ using declaration is controlled with this and could change how name
- lookup is performed.</p>
+<p>Here <tt>!14</tt> indicates that <tt>Z</tt> is declared at line number 5 and
+ column number 9 inside of lexical scope <tt>!13</tt>. The lexical scope
+ itself resides inside of lexical scope <tt>!1</tt> described above.</p>
+
+<p>The scope information attached with each instruction provides a
+ straightforward way to find instructions covered by a scope.</p>
+
+</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
<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>
<pre>
...
;;
-;; Define types used. In this case we need one for compile unit anchors and one
-;; for compile units.
-;;
-%<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint }
-%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = type { uint, { }*, uint, uint, i8*, i8*, i8* }
-...
-;;
-;; Define the anchor for compile units. Note that the second field of the
-;; anchor is 17, which is the same as the tag for compile units
-;; (17 = DW_TAG_compile_unit.)
+;; Define the compile unit for the main source file "/Users/mine/sources/MySource.cpp".
;;
-%<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"
+!2 = metadata !{
+ i32 524305, ;; Tag
+ i32 0, ;; Unused
+ i32 4, ;; Language Id
+ metadata !"MySource.cpp",
+ metadata !"/Users/mine/sources",
+ metadata !"4.2.1 (Based on Apple Inc. build 5649) (LLVM build 00)",
+ i1 true, ;; Main Compile Unit
+ i1 false, ;; Optimized compile unit
+ metadata !"", ;; Compiler flags
+ i32 0} ;; Runtime version
;;
-;; Define the compile unit for the source file "/Users/mine/sources/MySource.cpp".
-;;
-%<a href="#format_compile_units">llvm.dbg.compile_unit1</a> = internal constant %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> {
- uint add(uint 17, uint 262144),
- { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_units</a> to { }*),
- uint 1,
- uint 1,
- i8* getelementptr ([13 x i8]* %str1, i32 0, i32 0),
- i8* getelementptr ([21 x i8]* %str2, i32 0, i32 0),
- i8* getelementptr ([33 x i8]* %str3, i32 0, i32 0) }, section "llvm.metadata"
-
+;; Define the file for the file "/Users/mine/sources/MySource.cpp".
;;
-;; Define the compile unit for the header file "/Users/mine/sources/MyHeader.h".
-;;
-%<a href="#format_compile_units">llvm.dbg.compile_unit2</a> = internal constant %<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> {
- uint add(uint 17, uint 262144),
- { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_units</a> to { }*),
- uint 1,
- uint 1,
- i8* getelementptr ([11 x i8]* %str4, int 0, int 0),
- i8* getelementptr ([21 x i8]* %str2, int 0, int 0),
- i8* getelementptr ([33 x i8]* %str3, int 0, int 0) }, section "llvm.metadata"
+!1 = metadata !{
+ i32 524329, ;; Tag
+ metadata !"MySource.cpp",
+ metadata !"/Users/mine/sources",
+ metadata !2 ;; Compile unit
+}
;;
-;; Define each of the strings used in the compile units.
+;; Define the file for the file "/Users/mine/sources/Myheader.h"
;;
-%str1 = internal constant [13 x i8] c"MySource.cpp\00", section "llvm.metadata";
-%str2 = internal constant [21 x i8] c"/Users/mine/sources/\00", section "llvm.metadata";
-%str3 = internal constant [33 x i8] c"4.0.1 LLVM (LLVM research group)\00", section "llvm.metadata";
-%str4 = internal constant [11 x i8] c"MyHeader.h\00", section "llvm.metadata";
+!3 = metadata !{
+ i32 524329, ;; Tag
+ metadata !"Myheader.h"
+ metadata !"/Users/mine/sources",
+ metadata !2 ;; Compile unit
+}
+
...
</pre>
</div>
+<p>llvm::Instruction provides easy access to metadata attached with an
+instruction. One can extract line number information encoded in LLVM IR
+using <tt>Instruction::getMetadata()</tt> and
+<tt>DILocation::getLineNumber()</tt>.
+<pre>
+ if (MDNode *N = I->getMetadata("dbg")) { // Here I is an LLVM instruction
+ DILocation Loc(N); // DILocation is in DebugInfo.h
+ unsigned Line = Loc.getLineNumber();
+ StringRef File = Loc.getFilename();
+ StringRef Dir = Loc.getDirectory();
+ }
+</pre>
</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>
<div class="doc_code">
<pre>
;;
-;; Define types used. One for global variable anchors, one for the global
-;; variable descriptor, one for the global's basic type and one for the global's
-;; compile unit.
-;;
-%<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint }
-%<a href="#format_global_variables">llvm.dbg.global_variable.type</a> = type { uint, { }*, { }*, i8*, { }*, uint, { }*, bool, bool, { }*, uint }
-%<a href="#format_basic_type">llvm.dbg.basictype.type</a> = type { uint, { }*, i8*, { }*, int, uint, uint, uint, uint }
-%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = ...
-...
-;;
;; Define the global itself.
;;
%MyGlobal = global int 100
...
;;
-;; Define the anchor for global variables. Note that the second field of the
-;; anchor is 52, which is the same as the tag for global variables
-;; (52 = DW_TAG_variable.)
+;; List of debug info of globals
;;
-%<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"
+!llvm.dbg.gv = !{!0}
;;
;; Define the global variable descriptor. Note the reference to the global
;; variable anchor and the global variable itself.
;;
-%<a href="#format_global_variables">llvm.dbg.global_variable</a> = internal constant %<a href="#format_global_variables">llvm.dbg.global_variable.type</a> {
- uint add(uint 52, uint 262144),
- { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_global_variables">llvm.dbg.global_variables</a> to { }*),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([9 x i8]* %str1, int 0, int 0),
- i8* getelementptr ([1 x i8]* %str2, int 0, int 0),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- uint 1,
- { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*),
- bool false,
- bool true,
- { }* cast (int* %MyGlobal to { }*) }, section "llvm.metadata"
-
+!0 = metadata !{
+ i32 524340, ;; Tag
+ i32 0, ;; Unused
+ metadata !1, ;; Context
+ metadata !"MyGlobal", ;; Name
+ metadata !"MyGlobal", ;; Display Name
+ metadata !"MyGlobal", ;; Linkage Name
+ metadata !3, ;; Compile Unit
+ i32 1, ;; Line Number
+ metadata !4, ;; Type
+ i1 false, ;; Is a local variable
+ i1 true, ;; Is this a definition
+ i32* @MyGlobal ;; The global variable
+}
+
;;
;; Define the basic type of 32 bit signed integer. Note that since int is an
;; intrinsic type the source file is NULL and line 0.
;;
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([4 x i8]* %str3, int 0, int 0),
- { }* null,
- int 0,
- uint 32,
- uint 32,
- uint 0,
- uint 5 }, section "llvm.metadata"
+!4 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"int", ;; Name
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 32, ;; Size in Bits
+ i64 32, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 5 ;; Encoding
+}
-;;
-;; Define the names of the global variable and basic type.
-;;
-%str1 = internal constant [9 x i8] c"MyGlobal\00", section "llvm.metadata"
-%str2 = internal constant [1 x i8] c"\00", section "llvm.metadata"
-%str3 = internal constant [4 x i8] c"int\00", section "llvm.metadata"
</pre>
</div>
</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>
<div class="doc_code">
<pre>
-;;
-;; Define types used. One for subprogram anchors, one for the subprogram
-;; descriptor, one for the global's basic type and one for the subprogram's
-;; compile unit.
-;;
-%<a href="#format_subprograms">llvm.dbg.subprogram.type</a> = type { uint, { }*, { }*, i8*, { }*, bool, bool }
-%<a href="#format_anchors">llvm.dbg.anchor.type</a> = type { uint, uint }
-%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a> = ...
-
;;
;; Define the anchor for subprograms. Note that the second field of the
;; anchor is 46, which is the same as the tag for subprograms
;; (46 = DW_TAG_subprogram.)
;;
-%<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"
-
-;;
-;; Define the descriptor for the subprogram. TODO - more details.
-;;
-%<a href="#format_subprograms">llvm.dbg.subprogram</a> = internal constant %<a href="#format_subprograms">llvm.dbg.subprogram.type</a> {
- uint add(uint 46, uint 262144),
- { }* cast (%<a href="#format_anchors">llvm.dbg.anchor.type</a>* %<a href="#format_subprograms">llvm.dbg.subprograms</a> to { }*),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([5 x i8]* %str1, int 0, int 0),
- i8* getelementptr ([1 x i8]* %str2, int 0, int 0),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- uint 1,
- { }* null,
- bool false,
- bool true }, section "llvm.metadata"
-
-;;
-;; Define the name of the subprogram.
-;;
-%str1 = internal constant [5 x i8] c"main\00", section "llvm.metadata"
-%str2 = internal constant [1 x i8] c"\00", section "llvm.metadata"
-
+!6 = metadata !{
+ i32 524334, ;; Tag
+ i32 0, ;; Unused
+ metadata !1, ;; Context
+ metadata !"main", ;; Name
+ metadata !"main", ;; Display name
+ metadata !"main", ;; Linkage name
+ metadata !1, ;; File
+ i32 1, ;; Line number
+ metadata !4, ;; Type
+ i1 false, ;; Is local
+ 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.
;;
-int %main(int %argc, i8** %argv) {
+define i32 @main(i32 %argc, i8** %argv) {
...
}
</pre>
</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>
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([5 x i8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 32,
- uint 32,
- uint 0,
- uint 2 }, section "llvm.metadata"
-%str1 = internal constant [5 x i8] c"bool\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"bool", ;; Name
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 8, ;; Size in Bits
+ i64 8, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 2 ;; Encoding
+}
</pre>
</div>
</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>
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([5 x i8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 8,
- uint 8,
- uint 0,
- uint 6 }, section "llvm.metadata"
-%str1 = internal constant [5 x i8] c"char\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"char", ;; Name
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 8, ;; Size in Bits
+ i64 8, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 6 ;; Encoding
+}
</pre>
</div>
</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>
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([14 x i8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 8,
- uint 8,
- uint 0,
- uint 8 }, section "llvm.metadata"
-%str1 = internal constant [14 x i8] c"unsigned char\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"unsigned char",
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 8, ;; Size in Bits
+ i64 8, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 8 ;; Encoding
+}
</pre>
</div>
</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>
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([10 x i8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 16,
- uint 16,
- uint 0,
- uint 5 }, section "llvm.metadata"
-%str1 = internal constant [10 x i8] c"short int\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"short int",
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 16, ;; Size in Bits
+ i64 16, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 5 ;; Encoding
+}
</pre>
</div>
</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>
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([19 x i8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 16,
- uint 16,
- uint 0,
- uint 7 }, section "llvm.metadata"
-%str1 = internal constant [19 x i8] c"short unsigned int\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"short unsigned int",
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 16, ;; Size in Bits
+ i64 16, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 7 ;; Encoding
+}
</pre>
</div>
</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>
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([4 x i8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 32,
- uint 32,
- uint 0,
- uint 5 }, section "llvm.metadata"
-%str1 = internal constant [4 x i8] c"int\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"int", ;; Name
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 32, ;; Size in Bits
+ i64 32, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 5 ;; Encoding
+}
</pre></div>
</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>
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([13 x i8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 32,
- uint 32,
- uint 0,
- uint 7 }, section "llvm.metadata"
-%str1 = internal constant [13 x i8] c"unsigned int\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"unsigned int",
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 32, ;; Size in Bits
+ i64 32, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 7 ;; Encoding
+}
</pre>
</div>
</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>
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([14 x i8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 64,
- uint 64,
- uint 0,
- uint 5 }, section "llvm.metadata"
-%str1 = internal constant [14 x i8] c"long long int\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"long long int",
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 64, ;; Size in Bits
+ i64 64, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 5 ;; Encoding
+}
</pre>
</div>
</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>
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([23 x i8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 64,
- uint 64,
- uint 0,
- uint 7 }, section "llvm.metadata"
-%str1 = internal constant [23 x 8] c"long long unsigned int\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"long long unsigned int",
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 64, ;; Size in Bits
+ i64 64, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 7 ;; Encoding
+}
</pre>
</div>
</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>
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([6 x i8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 32,
- uint 32,
- uint 0,
- uint 4 }, section "llvm.metadata"
-%str1 = internal constant [6 x i8] c"float\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"float",
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 32, ;; Size in Bits
+ i64 32, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 4 ;; Encoding
+}
</pre>
</div>
</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>
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- 8* getelementptr ([7 x 8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 64,
- uint 64,
- uint 0,
- uint 4 }, section "llvm.metadata"
-%str1 = internal constant [7 x 8] c"double\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"double",;; Name
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 64, ;; Size in Bits
+ i64 64, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 4 ;; Encoding
+}
</pre>
</div>
</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>
;;
;; Define the typedef "IntPtr".
;;
-%<a href="#format_derived_type">llvm.dbg.derivedtype1</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
- uint add(uint 22, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([7 x 8]* %str1, int 0, int 0),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- int 1,
- uint 0,
- uint 0,
- uint 0,
- { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype2</a> to { }*) }, section "llvm.metadata"
-%str1 = internal constant [7 x 8] c"IntPtr\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524310, ;; Tag
+ metadata !1, ;; Context
+ metadata !"IntPtr", ;; Name
+ metadata !3, ;; File
+ i32 0, ;; Line number
+ i64 0, ;; Size in bits
+ i64 0, ;; Align in bits
+ i64 0, ;; Offset in bits
+ i32 0, ;; Flags
+ metadata !4 ;; Derived From type
+}
;;
;; Define the pointer type.
;;
-%<a href="#format_derived_type">llvm.dbg.derivedtype2</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
- uint add(uint 15, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* null,
- { }* null,
- int 0,
- uint 32,
- uint 32,
- uint 0,
- { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype3</a> to { }*) }, section "llvm.metadata"
-
+!4 = metadata !{
+ i32 524303, ;; Tag
+ metadata !1, ;; Context
+ metadata !"", ;; Name
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 64, ;; Size in bits
+ i64 64, ;; Align in bits
+ i64 0, ;; Offset in bits
+ i32 0, ;; Flags
+ metadata !5 ;; Derived From type
+}
;;
;; Define the const type.
;;
-%<a href="#format_derived_type">llvm.dbg.derivedtype3</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
- uint add(uint 38, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* null,
- { }* null,
- int 0,
- uint 0,
- uint 0,
- uint 0,
- { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype1</a> to { }*) }, section "llvm.metadata"
-
+!5 = metadata !{
+ i32 524326, ;; Tag
+ metadata !1, ;; Context
+ metadata !"", ;; Name
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 32, ;; Size in bits
+ i64 32, ;; Align in bits
+ i64 0, ;; Offset in bits
+ i32 0, ;; Flags
+ metadata !6 ;; Derived From type
+}
;;
;; Define the int type.
;;
-%<a href="#format_basic_type">llvm.dbg.basictype1</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- 8* getelementptr ([4 x 8]* %str2, int 0, int 0),
- { }* null,
- int 0,
- uint 32,
- uint 32,
- uint 0,
- uint 5 }, section "llvm.metadata"
-%str2 = internal constant [4 x 8] c"int\00", section "llvm.metadata"
+!6 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"int", ;; Name
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 32, ;; Size in bits
+ i64 32, ;; Align in bits
+ i64 0, ;; Offset in bits
+ i32 0, ;; Flags
+ 5 ;; Encoding
+}
</pre>
</div>
</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>
;;
;; Define basic type for unsigned int.
;;
-%<a href="#format_basic_type">llvm.dbg.basictype</a> = internal constant %<a href="#format_basic_type">llvm.dbg.basictype.type</a> {
- uint add(uint 36, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([13 x i8]* %str1, int 0, int 0),
- { }* null,
- int 0,
- uint 32,
- uint 32,
- uint 0,
- uint 7 }, section "llvm.metadata"
-%str1 = internal constant [13 x i8] c"unsigned int\00", section "llvm.metadata"
-
+!5 = metadata !{
+ i32 524324, ;; Tag
+ metadata !1, ;; Context
+ metadata !"unsigned int",
+ metadata !1, ;; File
+ i32 0, ;; Line number
+ i64 32, ;; Size in Bits
+ i64 32, ;; Align in Bits
+ i64 0, ;; Offset in Bits
+ i32 0, ;; Flags
+ i32 7 ;; Encoding
+}
;;
;; Define composite type for struct Color.
;;
-%<a href="#format_composite_type">llvm.dbg.compositetype</a> = internal constant %<a href="#format_composite_type">llvm.dbg.compositetype.type</a> {
- uint add(uint 19, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([6 x i8]* %str2, int 0, int 0),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- int 1,
- uint 96,
- uint 32,
- uint 0,
- { }* null,
- { }* cast ([3 x { }*]* %llvm.dbg.array to { }*) }, section "llvm.metadata"
-%str2 = internal constant [6 x i8] c"Color\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524307, ;; Tag
+ metadata !1, ;; Context
+ metadata !"Color", ;; Name
+ metadata !1, ;; Compile unit
+ i32 1, ;; Line number
+ i64 96, ;; Size in bits
+ i64 32, ;; Align in bits
+ i64 0, ;; Offset in bits
+ i32 0, ;; Flags
+ null, ;; Derived From
+ metadata !3, ;; Elements
+ i32 0 ;; Runtime Language
+}
;;
;; Define the Red field.
;;
-%<a href="#format_derived_type">llvm.dbg.derivedtype1</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
- uint add(uint 13, uint 262144),
- { }* null,
- i8* getelementptr ([4 x i8]* %str3, int 0, int 0),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- int 2,
- uint 32,
- uint 32,
- uint 0,
- { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata"
-%str3 = internal constant [4 x i8] c"Red\00", section "llvm.metadata"
+!4 = metadata !{
+ i32 524301, ;; Tag
+ metadata !1, ;; Context
+ metadata !"Red", ;; Name
+ metadata !1, ;; File
+ i32 2, ;; Line number
+ i64 32, ;; Size in bits
+ i64 32, ;; Align in bits
+ i64 0, ;; Offset in bits
+ i32 0, ;; Flags
+ metadata !5 ;; Derived From type
+}
;;
;; Define the Green field.
;;
-%<a href="#format_derived_type">llvm.dbg.derivedtype2</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
- uint add(uint 13, uint 262144),
- { }* null,
- i8* getelementptr ([6 x i8]* %str4, int 0, int 0),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- int 3,
- uint 32,
- uint 32,
- uint 32,
- { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata"
-%str4 = internal constant [6 x i8] c"Green\00", section "llvm.metadata"
+!6 = metadata !{
+ i32 524301, ;; Tag
+ metadata !1, ;; Context
+ metadata !"Green", ;; Name
+ metadata !1, ;; File
+ i32 3, ;; Line number
+ i64 32, ;; Size in bits
+ i64 32, ;; Align in bits
+ i64 32, ;; Offset in bits
+ i32 0, ;; Flags
+ metadata !5 ;; Derived From type
+}
;;
;; Define the Blue field.
;;
-%<a href="#format_derived_type">llvm.dbg.derivedtype3</a> = internal constant %<a href="#format_derived_type">llvm.dbg.derivedtype.type</a> {
- uint add(uint 13, uint 262144),
- { }* null,
- i8* getelementptr ([5 x i8]* %str5, int 0, int 0),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- int 4,
- uint 32,
- uint 32,
- uint 64,
- { }* cast (%<a href="#format_basic_type">llvm.dbg.basictype.type</a>* %<a href="#format_basic_type">llvm.dbg.basictype</a> to { }*) }, section "llvm.metadata"
-%str5 = internal constant [5 x 8] c"Blue\00", section "llvm.metadata"
+!7 = metadata !{
+ i32 524301, ;; Tag
+ metadata !1, ;; Context
+ metadata !"Blue", ;; Name
+ metadata !1, ;; File
+ i32 4, ;; Line number
+ i64 32, ;; Size in bits
+ i64 32, ;; Align in bits
+ i64 64, ;; Offset in bits
+ i32 0, ;; Flags
+ metadata !5 ;; Derived From type
+}
;;
;; Define the array of fields used by the composite type Color.
;;
-%llvm.dbg.array = internal constant [3 x { }*] [
- { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype1</a> to { }*),
- { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype2</a> to { }*),
- { }* cast (%<a href="#format_derived_type">llvm.dbg.derivedtype.type</a>* %<a href="#format_derived_type">llvm.dbg.derivedtype3</a> to { }*) ], section "llvm.metadata"
+!3 = metadata !{metadata !4, metadata !6, metadata !7}
</pre>
</div>
</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>
;;
;; Define composite type for enum Trees
;;
-%<a href="#format_composite_type">llvm.dbg.compositetype</a> = internal constant %<a href="#format_composite_type">llvm.dbg.compositetype.type</a> {
- uint add(uint 4, uint 262144),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- i8* getelementptr ([6 x i8]* %str1, int 0, int 0),
- { }* cast (%<a href="#format_compile_units">llvm.dbg.compile_unit.type</a>* %<a href="#format_compile_units">llvm.dbg.compile_unit</a> to { }*),
- int 1,
- uint 32,
- uint 32,
- uint 0,
- { }* null,
- { }* cast ([3 x { }*]* %llvm.dbg.array to { }*) }, section "llvm.metadata"
-%str1 = internal constant [6 x i8] c"Trees\00", section "llvm.metadata"
+!2 = metadata !{
+ i32 524292, ;; Tag
+ metadata !1, ;; Context
+ metadata !"Trees", ;; Name
+ metadata !1, ;; File
+ i32 1, ;; Line number
+ i64 32, ;; Size in bits
+ i64 32, ;; Align in bits
+ i64 0, ;; Offset in bits
+ i32 0, ;; Flags
+ null, ;; Derived From type
+ metadata !3, ;; Elements
+ i32 0 ;; Runtime language
+}
+
+;;
+;; Define the array of enumerators used by composite type Trees.
+;;
+!3 = metadata !{metadata !4, metadata !5, metadata !6}
;;
;; Define Spruce enumerator.
;;
-%<a href="#format_enumeration">llvm.dbg.enumerator1</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> {
- uint add(uint 40, uint 262144),
- i8* getelementptr ([7 x i8]* %str2, int 0, int 0),
- int 100 }, section "llvm.metadata"
-%str2 = internal constant [7 x i8] c"Spruce\00", section "llvm.metadata"
+!4 = metadata !{i32 524328, metadata !"Spruce", i64 100}
;;
;; Define Oak enumerator.
;;
-%<a href="#format_enumeration">llvm.dbg.enumerator2</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> {
- uint add(uint 40, uint 262144),
- i8* getelementptr ([4 x i8]* %str3, int 0, int 0),
- int 200 }, section "llvm.metadata"
-%str3 = internal constant [4 x i8] c"Oak\00", section "llvm.metadata"
+!5 = metadata !{i32 524328, metadata !"Oak", i64 200}
;;
;; Define Maple enumerator.
;;
-%<a href="#format_enumeration">llvm.dbg.enumerator3</a> = internal constant %<a href="#format_enumeration">llvm.dbg.enumerator.type</a> {
- uint add(uint 40, uint 262144),
- i8* getelementptr ([6 x i8]* %str4, int 0, int 0),
- int 300 }, section "llvm.metadata"
-%str4 = internal constant [6 x i8] c"Maple\00", section "llvm.metadata"
+!6 = metadata !{i32 524328, metadata !"Maple", i64 300}
-;;
-;; Define the array of enumerators used by composite type Trees.
-;;
-%llvm.dbg.array = internal constant [3 x { }*] [
- { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator1</a> to { }*),
- { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator2</a> to { }*),
- { }* cast (%<a href="#format_enumeration">llvm.dbg.enumerator.type</a>* %<a href="#format_enumeration">llvm.dbg.enumerator3</a> to { }*) ], section "llvm.metadata"
</pre>
</div>
</div>
+</div>
+
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<hr>
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>
+ <a href="http://llvm.org/">LLVM Compiler Infrastructure</a><br>
Last modified: $Date$
</address>
projects / oota-llvm.git / blobdiff