[llvm] r252268 - docs: Document function-attached metadata and IR changes from r252219.
Duncan P. N. Exon Smith via llvm-commits
llvm-commits at lists.llvm.org
Thu Nov 5 20:55:20 PST 2015
This is great; thanks.
> On 2015-Nov-05, at 18:41, Peter Collingbourne via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>
> Author: pcc
> Date: Thu Nov 5 20:41:02 2015
> New Revision: 252268
>
> URL: http://llvm.org/viewvc/llvm-project?rev=252268&view=rev
> Log:
> docs: Document function-attached metadata and IR changes from r252219.
>
> Modified:
> llvm/trunk/docs/LangRef.rst
> llvm/trunk/docs/SourceLevelDebugging.rst
>
> Modified: llvm/trunk/docs/LangRef.rst
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.rst?rev=252268&r1=252267&r2=252268&view=diff
> ==============================================================================
> --- llvm/trunk/docs/LangRef.rst (original)
> +++ llvm/trunk/docs/LangRef.rst Thu Nov 5 20:41:02 2015
> @@ -640,6 +640,7 @@ an optional :ref:`comdat <langref_comdat
> an optional :ref:`garbage collector name <gc>`, an optional :ref:`prefix <prefixdata>`,
> an optional :ref:`prologue <prologuedata>`,
> an optional :ref:`personality <personalityfn>`,
> +an optional list of attached :ref:`metadata <metadata>`,
> an opening curly brace, a list of basic blocks, and a closing curly brace.
>
> LLVM function declarations consist of the "``declare``" keyword, an
> @@ -688,7 +689,7 @@ Syntax::
> <ResultType> @<FunctionName> ([argument list])
> [unnamed_addr] [fn Attrs] [section "name"] [comdat [($name)]]
> [align N] [gc] [prefix Constant] [prologue Constant]
> - [personality Constant] { ... }
> + [personality Constant] (!name !N)* { ... }
>
> The argument list is a comma separated sequence of arguments where each
> argument is of the following form:
> @@ -3624,13 +3625,22 @@ function is using two metadata arguments
>
> call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
>
> -Metadata can be attached with an instruction. Here metadata ``!21`` is
> -attached to the ``add`` instruction using the ``!dbg`` identifier:
> +Metadata can be attached to an instruction. Here metadata ``!21`` is attached
> +to the ``add`` instruction using the ``!dbg`` identifier:
>
> .. code-block:: llvm
>
> %indvar.next = add i64 %indvar, 1, !dbg !21
>
> +Metadata can also be attached to a function definition. Here metadata ``!22``
> +is attached to the ``foo`` function using the ``!dbg`` identifier:
> +
> +.. code-block:: llvm
> +
> + define void @foo() !dbg !22 {
> + ret void
> + }
> +
> More information about specific metadata nodes recognized by the
> optimizers and code generator is found below.
>
> @@ -3901,20 +3911,26 @@ All global variables should be reference
> DISubprogram
> """"""""""""
>
> -``DISubprogram`` nodes represent functions from the source language. The
> -``variables:`` field points at :ref:`variables <DILocalVariable>` that must be
> -retained, even if their IR counterparts are optimized out of the IR. The
> -``type:`` field must point at an :ref:`DISubroutineType`.
> +``DISubprogram`` nodes represent functions from the source language. A
> +``DISubprogram`` may be attached to a function definition using ``!dbg``
> +metadata. The ``variables:`` field points at :ref:`variables <DILocalVariable>`
> +that must be retained, even if their IR counterparts are optimized out of
> +the IR. The ``type:`` field must point at an :ref:`DISubroutineType`.
>
> .. code-block:: llvm
>
> - !0 = !DISubprogram(name: "foo", linkageName: "_Zfoov", scope: !1,
> - file: !2, line: 7, type: !3, isLocal: true,
> - isDefinition: false, scopeLine: 8, containingType: !4,
> - virtuality: DW_VIRTUALITY_pure_virtual, virtualIndex: 10,
> - flags: DIFlagPrototyped, isOptimized: true,
> - function: void ()* @_Z3foov,
> - templateParams: !5, declaration: !6, variables: !7)
> + define void @_Z3foov() !dbg !0 {
> + ...
> + }
> +
> + !0 = distinct !DISubprogram(name: "foo", linkageName: "_Zfoov", scope: !1,
> + file: !2, line: 7, type: !3, isLocal: true,
> + isDefinition: false, scopeLine: 8,
> + containingType: !4,
> + virtuality: DW_VIRTUALITY_pure_virtual,
> + virtualIndex: 10, flags: DIFlagPrototyped,
> + isOptimized: true, templateParams: !5,
> + declaration: !6, variables: !7)
>
> .. _DILexicalBlock:
>
>
> Modified: llvm/trunk/docs/SourceLevelDebugging.rst
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/SourceLevelDebugging.rst?rev=252268&r1=252267&r2=252268&view=diff
> ==============================================================================
> --- llvm/trunk/docs/SourceLevelDebugging.rst (original)
> +++ llvm/trunk/docs/SourceLevelDebugging.rst Thu Nov 5 20:41:02 2015
> @@ -231,7 +231,7 @@ Compiled to LLVM, this function would be
> .. code-block:: llvm
>
> ; Function Attrs: nounwind ssp uwtable
> - define void @foo() #0 {
> + define void @foo() #0 !dbg !4 {
> entry:
> %X = alloca i32, align 4
> %Y = alloca i32, align 4
> @@ -263,7 +263,7 @@ Compiled to LLVM, this function would be
> !1 = !DIFile(filename: "/dev/stdin", directory: "/Users/dexonsmith/data/llvm/debug-info")
> !2 = !{}
> !3 = !{!4}
> - !4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, function: void ()* @foo, variables: !2)
> + !4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: false, variables: !2)
> !5 = !DISubroutineType(types: !6)
> !6 = !{null}
> !7 = !{i32 2, !"Dwarf Version", i32 2}
> @@ -304,10 +304,9 @@ scope information for the variable ``X``
> .. code-block:: llvm
>
> !14 = !DILocation(line: 2, column: 9, scope: !4)
> - !4 = !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !5,
> - isLocal: false, isDefinition: true, scopeLine: 1,
> - isOptimized: false, function: void ()* @foo,
> - variables: !2)
> + !4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !5,
> + isLocal: false, isDefinition: true, scopeLine: 1,
> + isOptimized: false, variables: !2)
>
> Here ``!14`` is metadata providing `location information
> <LangRef.html#dilocation>`_. In this example, scope is encoded by ``!4``, a
> @@ -463,12 +462,12 @@ a C/C++ front-end would generate the fol
> !4 = !DISubprogram(name: "main", scope: !1, file: !1, line: 1, type: !5,
> isLocal: false, isDefinition: true, scopeLine: 1,
> flags: DIFlagPrototyped, isOptimized: false,
> - function: i32 (i32, i8**)* @main, variables: !2)
> + variables: !2)
>
> ;;
> ;; Define the subprogram itself.
> ;;
> - define i32 @main(i32 %argc, i8** %argv) {
> + define i32 @main(i32 %argc, i8** %argv) !dbg !4 {
> ...
> }
>
>
>
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