From: Paul Robinson Date: Thu, 9 Nov 2017 20:01:31 +0000 (+0000) Subject: Fix out-of-order stepping behavior in programs with hoisted constants. X-Git-Tag: llvmorg-6.0.0-rc1~3757 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b46256b0b4ce0746b7d9c121a2572c17765cffea;p=platform%2Fupstream%2Fllvm.git Fix out-of-order stepping behavior in programs with hoisted constants. When the Constant Hoisting pass moves expensive constants into a common block, it would assign a debug location equal to the last use of that constant. While this is certainly intuitive, it places the constant in an out-of-order location, according to the debug location information. This produces out-of-order stepping when debugging programs affected by this pass. This patch creates in-order stepping behavior by merging the debug locations for hoisted constants, and the new insertion point. Patch by Matthew Voss! Differential Revision: https://reviews.llvm.org/D38088 llvm-svn: 317827 --- diff --git a/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp b/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp index 58a910de..e4b08c5 100644 --- a/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp +++ b/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp @@ -60,6 +60,7 @@ #include "llvm/Support/raw_ostream.h" #include "llvm/Transforms/Scalar.h" #include "llvm/Transforms/Utils/Local.h" +#include "llvm/IR/DebugInfoMetadata.h" #include #include #include @@ -716,6 +717,9 @@ bool ConstantHoistingPass::emitBaseConstants() { IntegerType *Ty = ConstInfo.BaseConstant->getType(); Instruction *Base = new BitCastInst(ConstInfo.BaseConstant, Ty, "const", IP); + + Base->setDebugLoc(IP->getDebugLoc()); + DEBUG(dbgs() << "Hoist constant (" << *ConstInfo.BaseConstant << ") to BB " << IP->getParent()->getName() << '\n' << *Base << '\n'); @@ -734,6 +738,8 @@ bool ConstantHoistingPass::emitBaseConstants() { emitBaseConstants(Base, RCI.Offset, U); ReBasesNum++; } + + Base->setDebugLoc(DILocation::getMergedLocation(Base->getDebugLoc(), U.Inst->getDebugLoc())); } } UsesNum = Uses; @@ -742,7 +748,6 @@ bool ConstantHoistingPass::emitBaseConstants() { assert(!Base->use_empty() && "The use list is empty!?"); assert(isa(Base->user_back()) && "All uses should be instructions."); - Base->setDebugLoc(cast(Base->user_back())->getDebugLoc()); } (void)UsesNum; (void)ReBasesNum; diff --git a/llvm/test/Transforms/ConstantHoisting/X86/dbg-dominatingblock.ll b/llvm/test/Transforms/ConstantHoisting/X86/dbg-dominatingblock.ll new file mode 100644 index 0000000..dfee412 --- /dev/null +++ b/llvm/test/Transforms/ConstantHoisting/X86/dbg-dominatingblock.ll @@ -0,0 +1,55 @@ +; RUN: opt -S -consthoist < %s | FileCheck %s +; ModuleID = 'test-hoist-debug.cpp' +source_filename = "test-hoist-debug.cpp" +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +; Function Attrs: noinline nounwind optnone uwtable +define i32 @_Z3foov() !dbg !7 { +; CHECK: bitcast +; CHECK-NOT: !dbg !11 +; CHECK: inttoptr +entry: + %a0 = inttoptr i64 4646526064 to i32* + %v0 = load i32, i32* %a0, align 16, !dbg !11 + %c = alloca i32, align 4 + store i32 1, i32* %c, align 4 + %0 = load i32, i32* %c, align 4 + %cmp = icmp eq i32 %0, 0 + br i1 %cmp, label %if.then, label %if.else + +if.then: ; preds = %entry + %a1 = inttoptr i64 4646526080 to i32* + %v1 = load i32, i32* %a1, align 16, !dbg !11 + br label %return + +if.else: ; preds = %entry + %a2 = inttoptr i64 4646526096 to i32* + %v2 = load i32, i32* %a2, align 16, !dbg !11 + br label %return + +return: ; preds = %if.else, %if.then + %vx = phi i32 [%v1, %if.then], [%v2, %if.else] + %r0 = add i32 %vx, %v0 + + ret i32 %r0 +} + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!3, !4, !5} +!llvm.ident = !{!6} + +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 6.0.0 (trunk 313291)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) +!1 = !DIFile(filename: "test-hoist-debug.cpp", directory: "/tmp") +!2 = !{} +!3 = !{i32 2, !"Dwarf Version", i32 4} +!4 = !{i32 2, !"Debug Info Version", i32 3} +!5 = !{i32 1, !"wchar_size", i32 4} +!6 = !{!"clang version 6.0.0 (trunk 313291)"} +!7 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2) +!8 = !DISubroutineType(types: !9) +!9 = !{!10} +!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!11 = !DILocation(line: 2, column: 3, scope: !7) +!12 = !DILocation(line: 3, column: 3, scope: !7) +!13 = !DILocation(line: 4, column: 3, scope: !7) diff --git a/llvm/test/Transforms/ConstantHoisting/X86/dbg-samebasicblock.ll b/llvm/test/Transforms/ConstantHoisting/X86/dbg-samebasicblock.ll new file mode 100644 index 0000000..f3fd5cf --- /dev/null +++ b/llvm/test/Transforms/ConstantHoisting/X86/dbg-samebasicblock.ll @@ -0,0 +1,41 @@ +; RUN: opt -S -consthoist < %s | FileCheck %s +; ModuleID = 'test-hoist-debug.cpp' +source_filename = "test-hoist-debug.cpp" +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +; Function Attrs: noinline nounwind optnone uwtable +define i32 @_Z3foov() !dbg !7 { +; CHECK: bitcast +; CHECK: !dbg !11 +; CHECK: inttoptr + %a0 = inttoptr i64 4646526064 to i32*, !dbg !11 + %v0 = load i32, i32* %a0, align 16, !dbg !11 + + %a1 = inttoptr i64 4646526080 to i32* + %v1 = load i32, i32* %a1, align 16, !dbg !11 + + %a2 = inttoptr i64 4646526096 to i32* + %v2 = load i32, i32* %a2, align 16, !dbg !11 + + %r0 = add i32 %v0, %v1 + %r1 = add i32 %r0, %v2 + ret i32 %r1 +} + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!3, !4, !5} +!llvm.ident = !{!6} + +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 6.0.0 (trunk 313291)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) +!1 = !DIFile(filename: "test-hoist-debug.cpp", directory: "/tmp") +!2 = !{} +!3 = !{i32 2, !"Dwarf Version", i32 4} +!4 = !{i32 2, !"Debug Info Version", i32 3} +!5 = !{i32 1, !"wchar_size", i32 4} +!6 = !{!"clang version 6.0.0 (trunk 313291)"} +!7 = distinct !DISubprogram(name: "foo", linkageName: "_Z3foov", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2) +!8 = !DISubroutineType(types: !9) +!9 = !{!10} +!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!11 = !DILocation(line: 2, column: 3, scope: !7)