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Update the discriminator assignment algorithm
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* If a scope has already been assigned a discriminator, do not reassign a nested discriminator for it.
* If the file and line both match, even if the column does not match, we should assign a new discriminator for the stmt.

original code:
; llvm-mirror#1 int foo(int i) {
; llvm-mirror#2 if (i == 3 || i == 5) return 100; else return 99;
; llvm-mirror#3 }

; i == 3: discriminator 0
; i == 5: discriminator 2
; return 100: discriminator 1
; return 99: discriminator 3


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251680 91177308-0d34-0410-b5e6-96231b3b80d8
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@danielcdh
danielcdh committed Oct 30, 2015
1 parent a18aee1 commit 8ce527d
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Showing 2 changed files with 110 additions and 11 deletions.
23 changes: 12 additions & 11 deletions lib/Transforms/Utils/AddDiscriminators.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -180,7 +180,7 @@ bool AddDiscriminators::runOnFunction(Function &F) {
BasicBlock *Succ = Last->getSuccessor(I);
Instruction *First = Succ->getFirstNonPHIOrDbgOrLifetime();
const DILocation *FirstDIL = First->getDebugLoc();
if (!FirstDIL)
if (!FirstDIL || FirstDIL->getDiscriminator())
continue;

// If the first instruction (First) of Succ is at the same file
Expand All @@ -202,21 +202,22 @@ bool AddDiscriminators::runOnFunction(Function &F) {
unsigned Discriminator = FirstDIL->computeNewDiscriminator();
auto *NewScope =
Builder.createLexicalBlockFile(Scope, File, Discriminator);
auto *NewDIL =
DILocation::get(Ctx, FirstDIL->getLine(), FirstDIL->getColumn(),
NewScope, FirstDIL->getInlinedAt());
DebugLoc newDebugLoc = NewDIL;

// Attach this new debug location to First and every
// instruction following First that shares the same location.
for (BasicBlock::iterator I1(*First), E1 = Succ->end(); I1 != E1;
++I1) {
if (I1->getDebugLoc().get() != FirstDIL)
break;
I1->setDebugLoc(newDebugLoc);
DEBUG(dbgs() << NewDIL->getFilename() << ":" << NewDIL->getLine()
<< ":" << NewDIL->getColumn() << ":"
<< NewDIL->getDiscriminator() << *I1 << "\n");
const DILocation *CurrentDIL = I1->getDebugLoc();
if (CurrentDIL && CurrentDIL->getLine() == FirstDIL->getLine() &&
CurrentDIL->getFilename() == FirstDIL->getFilename()) {
I1->setDebugLoc(DILocation::get(Ctx, CurrentDIL->getLine(),
CurrentDIL->getColumn(), NewScope,
CurrentDIL->getInlinedAt()));
DEBUG(dbgs() << CurrentDIL->getFilename() << ":"
<< CurrentDIL->getLine() << ":"
<< CurrentDIL->getColumn() << ":"
<< CurrentDIL->getDiscriminator() << *I1 << "\n");
}
}
DEBUG(dbgs() << "\n");
Changed = true;
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98 changes: 98 additions & 0 deletions test/Transforms/AddDiscriminators/oneline.ll
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Original file line number Diff line number Diff line change
@@ -0,0 +1,98 @@
; RUN: opt < %s -add-discriminators -S | FileCheck %s

; Discriminator support for code that is written in one line:
; #1 int foo(int i) {
; #2 if (i == 3 || i == 5) return 100; else return 99;
; #3 }

; i == 3: discriminator 0
; i == 5: discriminator 2
; return 100: discriminator 1
; return 99: discriminator 3

define i32 @_Z3fooi(i32 %i) #0 {
%1 = alloca i32, align 4
%2 = alloca i32, align 4
store i32 %i, i32* %2, align 4, !tbaa !13
call void @llvm.dbg.declare(metadata i32* %2, metadata !9, metadata !17), !dbg !18
%3 = load i32, i32* %2, align 4, !dbg !19, !tbaa !13
%4 = icmp eq i32 %3, 3, !dbg !21
br i1 %4, label %8, label %5, !dbg !22

; <label>:5 ; preds = %0
%6 = load i32, i32* %2, align 4, !dbg !23, !tbaa !13
; CHECK: %6 = load i32, i32* %2, align 4, !dbg ![[THEN1:[0-9]+]],{{.*}}

%7 = icmp eq i32 %6, 5, !dbg !24
; CHECK: %7 = icmp eq i32 %6, 5, !dbg ![[THEN2:[0-9]+]]

br i1 %7, label %8, label %9, !dbg !25
; CHECK: br i1 %7, label %8, label %9, !dbg ![[THEN3:[0-9]+]]

; <label>:8 ; preds = %5, %0
store i32 100, i32* %1, align 4, !dbg !26
; CHECK: store i32 100, i32* %1, align 4, !dbg ![[ELSE:[0-9]+]]

br label %10, !dbg !26
; CHECK: br label %10, !dbg ![[ELSE]]

; <label>:9 ; preds = %5
store i32 99, i32* %1, align 4, !dbg !27
; CHECK: store i32 99, i32* %1, align 4, !dbg ![[COMBINE:[0-9]+]]

br label %10, !dbg !27
; CHECK: br label %10, !dbg ![[COMBINE]]

; <label>:10 ; preds = %9, %8
%11 = load i32, i32* %1, align 4, !dbg !28
ret i32 %11, !dbg !28
}

; Function Attrs: nounwind readnone
declare void @llvm.dbg.declare(metadata, metadata, metadata) #1

attributes #0 = { nounwind uwtable "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
attributes #1 = { nounwind readnone }

!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!10, !11}
!llvm.ident = !{!12}

!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 250915)", isOptimized: true, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3)
!1 = !DIFile(filename: "a.cc", directory: "/usr/local/google/home/dehao/discr")
!2 = !{}
!3 = !{!4}
!4 = distinct !DISubprogram(name: "foo", linkageName: "_Z3fooi", scope: !1, file: !1, line: 1, type: !5, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, function: i32 (i32)* @_Z3fooi, variables: !8)
!5 = !DISubroutineType(types: !6)
!6 = !{!7, !7}
!7 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!8 = !{!9}
!9 = !DILocalVariable(name: "i", arg: 1, scope: !4, file: !1, line: 1, type: !7)
!10 = !{i32 2, !"Dwarf Version", i32 4}
!11 = !{i32 2, !"Debug Info Version", i32 3}
!12 = !{!"clang version 3.8.0 (trunk 250915)"}
!13 = !{!14, !14, i64 0}
!14 = !{!"int", !15, i64 0}
!15 = !{!"omnipotent char", !16, i64 0}
!16 = !{!"Simple C/C++ TBAA"}
!17 = !DIExpression()
!18 = !DILocation(line: 1, column: 13, scope: !4)
!19 = !DILocation(line: 2, column: 7, scope: !20)
!20 = distinct !DILexicalBlock(scope: !4, file: !1, line: 2, column: 7)
!21 = !DILocation(line: 2, column: 9, scope: !20)
!22 = !DILocation(line: 2, column: 14, scope: !20)
!23 = !DILocation(line: 2, column: 17, scope: !20)
!24 = !DILocation(line: 2, column: 19, scope: !20)
!25 = !DILocation(line: 2, column: 7, scope: !4)
!26 = !DILocation(line: 2, column: 25, scope: !20)
!27 = !DILocation(line: 2, column: 42, scope: !20)
!28 = !DILocation(line: 3, column: 1, scope: !4)

; CHECK: ![[THEN1]] = !DILocation(line: 2, column: 17, scope: ![[THENBLOCK:[0-9]+]])
; CHECK: ![[THENBLOCK]] = !DILexicalBlockFile({{.*}} discriminator: 2)
; CHECK: ![[THEN2]] = !DILocation(line: 2, column: 19, scope: ![[THENBLOCK]])
; CHECK: ![[THEN3]] = !DILocation(line: 2, column: 7, scope: ![[THENBLOCK]])
; CHECK: ![[ELSE]] = !DILocation(line: 2, column: 25, scope: ![[ELSEBLOCK:[0-9]+]])
; CHECK: ![[ELSEBLOCK]] = !DILexicalBlockFile({{.*}} discriminator: 1)
; CHECK: ![[COMBINE]] = !DILocation(line: 2, column: 42, scope: ![[COMBINEBLOCK:[0-9]+]])
; CHECK: ![[COMBINEBLOCK]] = !DILexicalBlockFile({{.*}} discriminator: 3)

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