<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>
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>
<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, te use of metadadta avoids duplicated dubgging information from
+ 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 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>
0x1000.)</p>
<p>The fields of debug descriptors used internally by LLVM
- are restricted to only the simple data types <tt>int</tt>, <tt>uint</tt>,
- <tt>bool</tt>, <tt>float</tt>, <tt>double</tt>, <tt>mdstring</tt> and
- <tt>mdnode</tt>. </p>
+ 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>
!1 = metadata !{
- uint, ;; A tag
+ 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 = 7 << 16 or 0x70000 or
- 458752.)</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>
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.</p>
-<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_subsubsection">
+ <a name="format_files">File descriptors</a>
+</div>
+
+<div class="doc_text">
+
+<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 ;; Reference to compile unit where defined
+}
+</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. Each file descriptor would be defined using a
+ compile unit. </p>
</div>
metadata, ;; Name
metadata, ;; Display name (fully qualified C++ name)
metadata, ;; MIPS linkage name (for C++)
- metadata, ;; Reference to compile unit where defined
+ 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)
metadata, ;; Name
metadata, ;; Display name (fully qualified C++ name)
metadata, ;; MIPS linkage name (for C++)
- metadata, ;; Reference to compile unit where defined
+ 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)
;; (DW_TAG_base_type)
metadata, ;; Reference to context (typically a compile unit)
metadata, ;; Name (may be "" for anonymous types)
- metadata, ;; Reference to compile unit where defined (may be NULL)
+ 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
i32, ;; Tag (see below)
metadata, ;; Reference to context
metadata, ;; Name (may be "" for anonymous types)
- metadata, ;; Reference to compile unit where defined (may be NULL)
+ metadata, ;; Reference to file where defined (may be NULL)
i32, ;; Line number where defined (may be 0)
i32, ;; Size in bits
i32, ;; Alignment in bits
i32, ;; Tag (see below)
metadata, ;; Reference to context
metadata, ;; Name (may be "" for anonymous types)
- metadata, ;; Reference to compile unit where defined (may be NULL)
+ 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
i32, ;; Tag (see below)
metadata, ;; Context
metadata, ;; Name
- metadata, ;; Reference to compile unit where defined
+ metadata, ;; Reference to file where defined
i32, ;; Line number where defined
metadata ;; Type descriptor
}
rules.</p>
<p>In order to handle this, the LLVM debug format uses the metadata attached to
- llvm instructions to encode line nuber and scoping information. Consider the
- following C fragment, for example:</p>
+ llvm instructions to encode line number and scoping information. Consider
+ the following C fragment, for example:</p>
<div class="doc_code">
<pre>
</pre>
</div>
-<p>Here <tt>!14</tt> indicates that <tt>Z</tt> is declaread at line number 5 and
+<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>
<pre>
...
;;
-;; Define the compile unit for the source file "/Users/mine/sources/MySource.cpp".
+;; Define the compile unit for the main source file "/Users/mine/sources/MySource.cpp".
;;
-!3 = metadata !{
- i32 458769, ;; Tag
+!2 = metadata !{
+ i32 524305, ;; Tag
i32 0, ;; Unused
i32 4, ;; Language Id
metadata !"MySource.cpp",
i32 0} ;; Runtime version
;;
-;; Define the compile unit for the header file "/Users/mine/sources/MyHeader.h".
+;; Define the file for the file "/Users/mine/sources/MySource.cpp".
;;
!1 = metadata !{
- i32 458769, ;; Tag
- i32 0, ;; Unused
- i32 4, ;; Language Id
- metadata !"MyHeader.h",
+ i32 524329, ;; Tag
+ metadata !"MySource.cpp",
metadata !"/Users/mine/sources",
- metadata !"4.2.1 (Based on Apple Inc. build 5649) (LLVM build 00)",
- i1 false, ;; Main Compile Unit
- i1 false, ;; Optimized compile unit
- metadata !"", ;; Compiler flags
- i32 0} ;; Runtime version
+ metadata !3 ;; Compile unit
+}
+
+;;
+;; Define the file for the file "/Users/mine/sources/Myheader.h"
+;;
+!3 = metadata !{
+ i32 524329, ;; Tag
+ metadata !"Myheader.h"
+ metadata !"/Users/mine/sources",
+ metadata !3 ;; 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>
<!-- ======================================================================= -->
;; variable anchor and the global variable itself.
;;
!0 = metadata !{
- i32 458804, ;; Tag
+ i32 524340, ;; Tag
i32 0, ;; Unused
metadata !1, ;; Context
metadata !"MyGlobal", ;; Name
metadata !"MyGlobal", ;; Display Name
metadata !"MyGlobal", ;; Linkage Name
- metadata !1, ;; Compile Unit
+ metadata !3, ;; Compile Unit
i32 1, ;; Line Number
- metadata !2, ;; Type
+ 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.
;;
-!2 = metadata !{
- i32 458788, ;; Tag
+!4 = metadata !{
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"int", ;; Name
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 32, ;; Size in Bits
i64 32, ;; Align in Bits
;; anchor is 46, which is the same as the tag for subprograms
;; (46 = DW_TAG_subprogram.)
;;
-!0 = metadata !{
- i32 458798, ;; Tag
+!6 = metadata !{
+ i32 524334, ;; Tag
i32 0, ;; Unused
metadata !1, ;; Context
metadata !"main", ;; Name
metadata !"main", ;; Display name
metadata !"main", ;; Linkage name
- metadata !1, ;; Compile unit
+ metadata !1, ;; File
i32 1, ;; Line number
- metadata !2, ;; Type
+ metadata !4, ;; Type
i1 false, ;; Is local
i1 true ;; Is definition
}
<div class="doc_code">
<pre>
!2 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"bool", ;; Name
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 8, ;; Size in Bits
i64 8, ;; Align in Bits
<div class="doc_code">
<pre>
!2 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"char", ;; Name
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 8, ;; Size in Bits
i64 8, ;; Align in Bits
<div class="doc_code">
<pre>
!2 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"unsigned char",
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 8, ;; Size in Bits
i64 8, ;; Align in Bits
<div class="doc_code">
<pre>
!2 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"short int",
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 16, ;; Size in Bits
i64 16, ;; Align in Bits
<div class="doc_code">
<pre>
!2 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"short unsigned int",
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 16, ;; Size in Bits
i64 16, ;; Align in Bits
<div class="doc_code">
<pre>
!2 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"int", ;; Name
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 32, ;; Size in Bits
i64 32, ;; Align in Bits
<div class="doc_code">
<pre>
!2 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"unsigned int",
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 32, ;; Size in Bits
i64 32, ;; Align in Bits
<div class="doc_code">
<pre>
!2 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"long long int",
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 64, ;; Size in Bits
i64 64, ;; Align in Bits
<div class="doc_code">
<pre>
!2 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"long long unsigned int",
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 64, ;; Size in Bits
i64 64, ;; Align in Bits
<div class="doc_code">
<pre>
!2 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"float",
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 32, ;; Size in Bits
i64 32, ;; Align in Bits
<div class="doc_code">
<pre>
!2 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"double",;; Name
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 64, ;; Size in Bits
i64 64, ;; Align in Bits
;; Define the typedef "IntPtr".
;;
!2 = metadata !{
- i32 458774, ;; Tag
+ i32 524310, ;; Tag
metadata !1, ;; Context
metadata !"IntPtr", ;; Name
- metadata !3, ;; Compile unit
+ metadata !3, ;; File
i32 0, ;; Line number
i64 0, ;; Size in bits
i64 0, ;; Align in bits
;; Define the pointer type.
;;
!4 = metadata !{
- i32 458767, ;; Tag
+ i32 524303, ;; Tag
metadata !1, ;; Context
metadata !"", ;; Name
- metadata !1, ;; Compile unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 64, ;; Size in bits
i64 64, ;; Align in bits
;; Define the const type.
;;
!5 = metadata !{
- i32 458790, ;; Tag
+ i32 524326, ;; Tag
metadata !1, ;; Context
metadata !"", ;; Name
- metadata !1, ;; Compile unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 32, ;; Size in bits
i64 32, ;; Align in bits
;; Define the int type.
;;
!6 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"int", ;; Name
- metadata !1, ;; Compile unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 32, ;; Size in bits
i64 32, ;; Align in bits
;; Define basic type for unsigned int.
;;
!5 = metadata !{
- i32 458788, ;; Tag
+ i32 524324, ;; Tag
metadata !1, ;; Context
metadata !"unsigned int",
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 0, ;; Line number
i64 32, ;; Size in Bits
i64 32, ;; Align in Bits
;; Define composite type for struct Color.
;;
!2 = metadata !{
- i32 458771, ;; Tag
+ i32 524307, ;; Tag
metadata !1, ;; Context
metadata !"Color", ;; Name
metadata !1, ;; Compile unit
;; Define the Red field.
;;
!4 = metadata !{
- i32 458765, ;; Tag
+ i32 524301, ;; Tag
metadata !1, ;; Context
metadata !"Red", ;; Name
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 2, ;; Line number
i64 32, ;; Size in bits
i64 32, ;; Align in bits
;; Define the Green field.
;;
!6 = metadata !{
- i32 458765, ;; Tag
+ i32 524301, ;; Tag
metadata !1, ;; Context
metadata !"Green", ;; Name
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 3, ;; Line number
i64 32, ;; Size in bits
i64 32, ;; Align in bits
;; Define the Blue field.
;;
!7 = metadata !{
- i32 458765, ;; Tag
+ i32 524301, ;; Tag
metadata !1, ;; Context
metadata !"Blue", ;; Name
- metadata !1, ;; Compile Unit
+ metadata !1, ;; File
i32 4, ;; Line number
i64 32, ;; Size in bits
i64 32, ;; Align in bits
;; Define composite type for enum Trees
;;
!2 = metadata !{
- i32 458756, ;; Tag
+ i32 524292, ;; Tag
metadata !1, ;; Context
metadata !"Trees", ;; Name
- metadata !1, ;; Compile unit
+ metadata !1, ;; File
i32 1, ;; Line number
i64 32, ;; Size in bits
i64 32, ;; Align in bits
;;
;; Define Spruce enumerator.
;;
-!4 = metadata !{i32 458792, metadata !"Spruce", i64 100}
+!4 = metadata !{i32 524328, metadata !"Spruce", i64 100}
;;
;; Define Oak enumerator.
;;
-!5 = metadata !{i32 458792, metadata !"Oak", i64 200}
+!5 = metadata !{i32 524328, metadata !"Oak", i64 200}
;;
;; Define Maple enumerator.
;;
-!6 = metadata !{i32 458792, metadata !"Maple", i64 300}
+!6 = metadata !{i32 524328, metadata !"Maple", i64 300}
</pre>
</div>
projects / oota-llvm.git / blobdiff