Reimplement discriminator assignment algorithm.

Summary: The new algorithm is more efficient (O(n), n is number of basic blocks). And it is guaranteed to cover all cases of multiple BB mapped to same line.

Reviewers: dblaikie, davidxl, dnovillo

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14738

llvm-svn: 253594

2 files changed, 76 insertions, 4 deletions

diff --git a/llvm/test/Transforms/AddDiscriminators/diamond.ll b/llvm/test/Transforms/AddDiscriminators/diamond.ll
new file mode 100644
index 00000000000..2ca638a83ec
--- /dev/null
+++ b/llvm/test/Transforms/AddDiscriminators/diamond.ll
@@ -0,0 +1,72 @@
+; RUN: opt < %s -add-discriminators -S | FileCheck %s
+
+; Discriminator support for diamond-shaped CFG.:
+; #1 void bar(int);
+; #2 
+; #3 void foo(int i) {
+; #4   if (i > 10)
+; #5     bar(5); else bar(3);
+; #6 }
+
+; bar(5):     discriminator 0
+; bar(3):     discriminator 1
+
+; Function Attrs: uwtable
+define void @_Z3fooi(i32 %i) #0 !dbg !4 {
+  %1 = alloca i32, align 4
+  store i32 %i, i32* %1, align 4
+  call void @llvm.dbg.declare(metadata i32* %1, metadata !11, metadata !12), !dbg !13
+  %2 = load i32, i32* %1, align 4, !dbg !14
+  %3 = icmp sgt i32 %2, 10, !dbg !16
+  br i1 %3, label %4, label %5, !dbg !17
+
+; <label>:4                                       ; preds = %0
+  call void @_Z3bari(i32 5), !dbg !18
+  br label %6, !dbg !18
+
+; <label>:5                                       ; preds = %0
+  call void @_Z3bari(i32 3), !dbg !19
+; CHECK:  call void @_Z3bari(i32 3), !dbg ![[ELSE:[0-9]+]]
+  br label %6
+
+; <label>:6                                       ; preds = %5, %4
+  ret void, !dbg !20
+}
+
+; Function Attrs: nounwind readnone
+declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
+
+declare void @_Z3bari(i32) #2
+
+attributes #0 = { uwtable "disable-tail-calls"="false" "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" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { nounwind readnone }
+attributes #2 = { "disable-tail-calls"="false" "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" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2" "unsafe-fp-math"="false" "use-soft-float"="false" }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!8, !9}
+!llvm.ident = !{!10}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 3.8.0 (trunk 253273)", isOptimized: false, runtimeVersion: 0, emissionKind: 1, enums: !2, subprograms: !3)
+!1 = !DIFile(filename: "a.cc", directory: "/tmp")
+!2 = !{}
+!3 = !{!4}
+!4 = distinct !DISubprogram(name: "foo", linkageName: "_Z3fooi", scope: !1, file: !1, line: 3, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: false, variables: !2)
+!5 = !DISubroutineType(types: !6)
+!6 = !{null, !7}
+!7 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
+!8 = !{i32 2, !"Dwarf Version", i32 4}
+!9 = !{i32 2, !"Debug Info Version", i32 3}
+!10 = !{!"clang version 3.8.0 (trunk 253273)"}
+!11 = !DILocalVariable(name: "i", arg: 1, scope: !4, file: !1, line: 3, type: !7)
+!12 = !DIExpression()
+!13 = !DILocation(line: 3, column: 14, scope: !4)
+!14 = !DILocation(line: 4, column: 7, scope: !15)
+!15 = distinct !DILexicalBlock(scope: !4, file: !1, line: 4, column: 7)
+!16 = !DILocation(line: 4, column: 9, scope: !15)
+!17 = !DILocation(line: 4, column: 7, scope: !4)
+!18 = !DILocation(line: 5, column: 5, scope: !15)
+!19 = !DILocation(line: 5, column: 18, scope: !15)
+!20 = !DILocation(line: 6, column: 1, scope: !4)
+
+; CHECK: ![[ELSE]] = !DILocation(line: 5, column: 18, scope: ![[ELSEBLOCK:[0-9]+]])
+; CHECK: ![[ELSEBLOCK]] = !DILexicalBlockFile({{.*}} discriminator: 1)
diff --git a/llvm/test/Transforms/AddDiscriminators/oneline.ll b/llvm/test/Transforms/AddDiscriminators/oneline.ll
index 9cb9e1dc61e..ebee3935dd6 100644
--- a/llvm/test/Transforms/AddDiscriminators/oneline.ll
+++ b/llvm/test/Transforms/AddDiscriminators/oneline.ll
@@ -6,8 +6,8 @@
 ; #3 }
 
 ; i == 3:     discriminator 0
-; i == 5:     discriminator 2
-; return 100: discriminator 1
+; i == 5:     discriminator 1
+; return 100: discriminator 2
 ; return 99:  discriminator 3
 
 define i32 @_Z3fooi(i32 %i) #0 !dbg !4 {
@@ -93,10 +93,10 @@ attributes #1 = { nounwind readnone }
 !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: ![[THENBLOCK]] = !DILexicalBlockFile({{.*}} discriminator: 1)
 ; 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: ![[ELSEBLOCK]] = !DILexicalBlockFile({{.*}} discriminator: 2)
 ; CHECK: ![[COMBINE]] = !DILocation(line: 2, column: 42, scope: ![[COMBINEBLOCK:[0-9]+]])
 ; CHECK: ![[COMBINEBLOCK]] = !DILexicalBlockFile({{.*}} discriminator: 3)