[LLVMdev] Does llvm-gcc emit column # info?
Kecheng
kecheng at cecs.pdx.edu
Mon Apr 26 11:02:19 PDT 2010
Hi Duncan,
But in the doc "Source Level Debugging with LLVM", it shows that llvm 2.6 could get column number. There's an example in the doc as following:
http://llvm.org/docs/SourceLevelDebugging.html
1. void foo() {
2. int X = 21;
3. int Y = 22;
4. {
5. int Z = 23;
6. Z = X;
7. }
8. X = Y;
9. }
Compiled to LLVM, this function would be represented like this:
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({ }* %0, metadata !0), !dbg !7
store i32 21, i32* %X, !dbg !8
%1 = bitcast i32* %Y to { }* ; <{ }*> [#uses=1]
call void @llvm.dbg.declare({ }* %1, metadata !9), !dbg !10
store i32 22, i32* %Y, !dbg !11
%2 = bitcast i32* %Z to { }* ; <{ }*> [#uses=1]
call void @llvm.dbg.declare({ }* %2, 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) 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}
We tried the exactly same C code, but in our's ll file, all coulmn field are 0. I suspect that we missed some options. Please advise. Thanks. Here's how we compiled and our ll file:
llvm-gcc -O0 -g -emit-llvm -c t.c -S -o t.ll
define void @main() nounwind {
entry:
%X = alloca i32 ; <i32*> [#uses=3]
%Y = alloca i32 ; <i32*> [#uses=2]
%Z = alloca i32 ; <i32*> [#uses=2]
%"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
call void @llvm.dbg.declare(metadata !{i32* %X}, metadata !0), !dbg !7
call void @llvm.dbg.declare(metadata !{i32* %Y}, metadata !8), !dbg !7
store i32 21, i32* %X, align 4, !dbg !9
store i32 22, i32* %Y, align 4, !dbg !10
call void @llvm.dbg.declare(metadata !{i32* %Z}, metadata !11), !dbg !13
store i32 23, i32* %Z, align 4, !dbg !14
%0 = load i32* %X, align 4, !dbg !15 ; <i32> [#uses=1]
store i32 %0, i32* %Z, align 4, !dbg !15
%1 = load i32* %Y, align 4, !dbg !16 ; <i32> [#uses=1]
store i32 %1, i32* %X, align 4, !dbg !16
br label %return, !dbg !17
return: ; preds = %entry
ret void, !dbg !17
}
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, i32 0, i32 0} ; [ DW_TAG_lexical_block ]
!2 = metadata !{i32 458798, i32 0, metadata !3, metadata !"main", metadata !"main", metadata !"main", metadata !3, i32 1, metadata !4, i1 false, i1 true, i32 0, i32 0, null, i1 false} ; [ DW_TAG_subprogram ]
!3 = metadata !{i32 458769, i32 0, i32 1, metadata !"t.c", metadata !"/home/kecheng/llvm_test/xyz/", metadata !"4.2.1 (Based on Apple Inc. build 5658) (LLVM build)", i1 true, i1 false, metadata !"", i32 0} ; [ DW_TAG_compile_unit ]
!4 = metadata !{i32 458773, metadata !3, metadata !"", metadata !3, i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !5, i32 0, null} ; [ 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 1, i32 0, metadata !1, null}
!8 = metadata !{i32 459008, metadata !1, metadata !"Y", metadata !3, i32 3, metadata !6} ; [ DW_TAG_auto_variable ]
!9 = metadata !{i32 2, i32 0, metadata !1, null}
!10 = metadata !{i32 3, i32 0, metadata !1, null}
!11 = metadata !{i32 459008, metadata !12, metadata !"Z", metadata !3, i32 5, metadata !6} ; [ DW_TAG_auto_variable ]
!12 = metadata !{i32 458763, metadata !1, i32 0, i32 0} ; [ DW_TAG_lexical_block ]
!13 = metadata !{i32 3, i32 0, metadata !12, null}
!14 = metadata !{i32 5, i32 0, metadata !12, null}
!15 = metadata !{i32 6, i32 0, metadata !12, null}
!16 = metadata !{i32 8, i32 0, metadata !1, null}
!17 = metadata !{i32 9, i32 0, metadata !1, null}
Kecheng
2010-04-26
From： Duncan Sands
Date： 2010-04-26 05:14:19
To： llvmdev
Cc：
Subject： Re: [LLVMdev] Does llvm-gcc emit column # info?
Hi Sheng,
> I tried llvm-gcc -g -O0 on several cases, but the column field of meta
> data always shows zero in created ll code.
>
> Does llvm-gcc emit column # info ? Or I should add some option?
as far as I knowm, llvm-gcc doesn't emit column info because it is based on
gcc-4.2 which has no support for column info. I think gcc-4.5 has column
info, so the dragonegg plugin (http://dragonegg.llvm.org) could in theory
output column info, though it doesn't right now.
Ciao,
Duncan.
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