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llvm-6502/test/Transforms/AddDiscriminators/first-only.ll

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Pass to emit DWARF path discriminators. DWARF discriminators are used to distinguish multiple control flow paths on the same source location. When this happens, instructions across basic block boundaries will share the same debug location. This pass detects this situation and creates a new lexical scope to one of the two instructions. This lexical scope is a child scope of the original and contains a new discriminator value. This discriminator is then picked up from MCObjectStreamer::EmitDwarfLocDirective to be written on the object file. This fixes http://llvm.org/bugs/show_bug.cgi?id=18270. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202752 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-03 20:06:11 +00:00
; RUN: opt < %s -add-discriminators -S | FileCheck %s
; Test that the only instructions that receive a new discriminator in
; the block 'if.then' are those that share the same line number as
; the branch in 'entry'.
;
; Original code:
;
; void foo(int i) {
; int x, y;
; if (i < 10) { x = i;
; y = -i;
; }
; }
define void @foo(i32 %i) #0 {
entry:
%i.addr = alloca i32, align 4
%x = alloca i32, align 4
%y = alloca i32, align 4
store i32 %i, i32* %i.addr, align 4
%0 = load i32* %i.addr, align 4, !dbg !10
%cmp = icmp slt i32 %0, 10, !dbg !10
br i1 %cmp, label %if.then, label %if.end, !dbg !10
if.then: ; preds = %entry
%1 = load i32* %i.addr, align 4, !dbg !12
store i32 %1, i32* %x, align 4, !dbg !12
%2 = load i32* %i.addr, align 4, !dbg !14
; CHECK: %2 = load i32* %i.addr, align 4, !dbg !15
%sub = sub nsw i32 0, %2, !dbg !14
; CHECK: %sub = sub nsw i32 0, %2, !dbg !15
store i32 %sub, i32* %y, align 4, !dbg !14
; CHECK: store i32 %sub, i32* %y, align 4, !dbg !15
br label %if.end, !dbg !15
; CHECK: br label %if.end, !dbg !16
if.end: ; preds = %if.then, %entry
ret void, !dbg !16
; CHECK: ret void, !dbg !17
}
attributes #0 = { nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!7, !8}
!llvm.ident = !{!9}
!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang version 3.5 (trunk 199750) (llvm/trunk 199751)", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !2, metadata !2, metadata !""} ; [ DW_TAG_compile_unit ] [first-only.c] [DW_LANG_C99]
!1 = metadata !{metadata !"first-only.c", metadata !"."}
!2 = metadata !{i32 0}
!3 = metadata !{metadata !4}
!4 = metadata !{i32 786478, metadata !1, metadata !5, metadata !"foo", metadata !"foo", metadata !"", i32 1, metadata !6, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 false, void (i32)* @foo, null, null, metadata !2, i32 1} ; [ DW_TAG_subprogram ] [line 1] [def] [foo]
!5 = metadata !{i32 786473, metadata !1} ; [ DW_TAG_file_type ] [first-only.c]
!6 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !2, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
!7 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
!8 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
!9 = metadata !{metadata !"clang version 3.5 (trunk 199750) (llvm/trunk 199751)"}
!10 = metadata !{i32 3, i32 0, metadata !11, null}
!11 = metadata !{i32 786443, metadata !1, metadata !4, i32 3, i32 0, i32 0} ; [ DW_TAG_lexical_block ] [first-only.c]
; CHECK: !11 = metadata !{i32 786443, metadata !1, metadata !4, i32 3, i32 0, i32 0}
!12 = metadata !{i32 3, i32 0, metadata !13, null}
!13 = metadata !{i32 786443, metadata !1, metadata !11, i32 3, i32 0, i32 1} ; [ DW_TAG_lexical_block ] [first-only.c]
Use DILexicalBlockFile, rather than DILexicalBlock, to track discriminator changes to ensure discriminator changes don't introduce new DWARF DW_TAG_lexical_blocks. Somewhat unnoticed in the original implementation of discriminators, but it could cause instructions to end up in new, small, DW_TAG_lexical_blocks due to the use of DILexicalBlock to track discriminator changes. Instead, use DILexicalBlockFile which we already use to track file changes without introducing new scopes, so it works well to track discriminator changes in the same way. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216239 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-21 22:45:21 +00:00
; CHECK: !13 = metadata !{i32 786443, metadata !1, metadata !14, i32 1} ; [ DW_TAG_lexical_block ] [./first-only.c]
Pass to emit DWARF path discriminators. DWARF discriminators are used to distinguish multiple control flow paths on the same source location. When this happens, instructions across basic block boundaries will share the same debug location. This pass detects this situation and creates a new lexical scope to one of the two instructions. This lexical scope is a child scope of the original and contains a new discriminator value. This discriminator is then picked up from MCObjectStreamer::EmitDwarfLocDirective to be written on the object file. This fixes http://llvm.org/bugs/show_bug.cgi?id=18270. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202752 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-03 20:06:11 +00:00
!14 = metadata !{i32 4, i32 0, metadata !13, null}
; CHECK: !14 = metadata !{i32 786443, metadata !1, metadata !11, i32 3, i32 0, i32 1}
!15 = metadata !{i32 5, i32 0, metadata !13, null}
; CHECK: !15 = metadata !{i32 4, i32 0, metadata !14, null}
!16 = metadata !{i32 6, i32 0, metadata !4, null}
; CHECK: !16 = metadata !{i32 5, i32 0, metadata !14, null}
; CHECK: !17 = metadata !{i32 6, i32 0, metadata !4, null}
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