From: Adrian Prantl Date: Tue, 28 Feb 2017 16:58:13 +0000 (+0000) Subject: Strip debug info when inlining into a nodebug function. X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9fa4de797ebb0b5aaa4eedbe63ab38464370caf6;p=llvm Strip debug info when inlining into a nodebug function. The LLVM backend cannot produce any debug info for an llvm::Function without a DISubprogram attachment. When inlining a debug-info-carrying function into a nodebug function, there is therefore no reason to keep any debug info intrinsic calls or debug locations on the instructions. This fixes a problem discovered in PR32042. rdar://problem/30679307 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@296488 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp index bd3aa8d3867..9873e8ebebe 100644 --- a/lib/Transforms/Utils/InlineFunction.cpp +++ b/lib/Transforms/Utils/InlineFunction.cpp @@ -1343,22 +1343,26 @@ static bool allocaWouldBeStaticInEntry(const AllocaInst *AI ) { return isa(AI->getArraySize()) && !AI->isUsedWithInAlloca(); } -/// Update inlined instructions' line numbers to -/// to encode location where these instructions are inlined. -static void fixupLineNumbers(Function *Fn, Function::iterator FI, - Instruction *TheCall, bool CalleeHasDebugInfo) { +/// Update inlined instructions' line numbers to to encode location where these +/// instructions are inlined. Also strip all debug intrinsics that were inlined +/// into a nodebug function; there is no debug info the backend could produce +/// for a function without a DISubprogram attachment. +static void fixupDebugInfo(Function *Fn, Function::iterator FI, + Instruction *TheCall, bool CalleeHasDebugInfo) { + bool CallerHasDebugInfo = Fn->getSubprogram(); + bool StripDebugInfo = !CallerHasDebugInfo && CalleeHasDebugInfo; + SmallVector IntrinsicsToErase; const DebugLoc &TheCallDL = TheCall->getDebugLoc(); - if (!TheCallDL) - return; auto &Ctx = Fn->getContext(); - DILocation *InlinedAtNode = TheCallDL; + DILocation *InlinedAtNode = nullptr; // Create a unique call site, not to be confused with any other call from the // same location. - InlinedAtNode = DILocation::getDistinct( - Ctx, InlinedAtNode->getLine(), InlinedAtNode->getColumn(), - InlinedAtNode->getScope(), InlinedAtNode->getInlinedAt()); + if (TheCallDL) + InlinedAtNode = DILocation::getDistinct( + Ctx, TheCallDL->getLine(), TheCallDL->getColumn(), + TheCallDL->getScope(), TheCallDL->getInlinedAt()); // Cache the inlined-at nodes as they're built so they are reused, without // this every instruction's inlined-at chain would become distinct from each @@ -1368,6 +1372,17 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI, for (; FI != Fn->end(); ++FI) { for (BasicBlock::iterator BI = FI->begin(), BE = FI->end(); BI != BE; ++BI) { + if (StripDebugInfo) { + // Inlining into a nodebug function. + if (auto *DI = dyn_cast(BI)) + // Mark dead debug intrinsics for deletion. + IntrinsicsToErase.push_back(DI); + else + // Remove the dangling debug location. + BI->setDebugLoc(DebugLoc()); + continue; + } + if (DebugLoc DL = BI->getDebugLoc()) { BI->setDebugLoc( updateInlinedAtInfo(DL, InlinedAtNode, BI->getContext(), IANodes)); @@ -1390,6 +1405,9 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI, BI->setDebugLoc(TheCallDL); } } + + for (auto *DI : IntrinsicsToErase) + DI->eraseFromParent(); } /// Update the block frequencies of the caller after a callee has been inlined. /// @@ -1710,8 +1728,8 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI, // For 'nodebug' functions, the associated DISubprogram is always null. // Conservatively avoid propagating the callsite debug location to // instructions inlined from a function whose DISubprogram is not null. - fixupLineNumbers(Caller, FirstNewBlock, TheCall, - CalledFunc->getSubprogram() != nullptr); + fixupDebugInfo(Caller, FirstNewBlock, TheCall, + CalledFunc->getSubprogram() != nullptr); // Clone existing noalias metadata if necessary. CloneAliasScopeMetadata(CS, VMap); diff --git a/test/Transforms/Inline/local-as-metadata-undominated-use.ll b/test/Transforms/Inline/local-as-metadata-undominated-use.ll index 474bba4cbbc..591fe090acc 100644 --- a/test/Transforms/Inline/local-as-metadata-undominated-use.ll +++ b/test/Transforms/Inline/local-as-metadata-undominated-use.ll @@ -16,14 +16,14 @@ entry: } ; CHECK-LABEL: define i32 @caller( -define i32 @caller(i32 %i) { +define i32 @caller(i32 %i) !dbg !3 { ; CHECK-NEXT: entry: entry: ; Although the inliner shouldn't crash, it can't be expected to get the ; "correct" SSA value since its assumptions have been violated. ; CHECK-NEXT: tail call void @llvm.dbg.value(metadata ![[EMPTY:[0-9]+]], ; CHECK-NEXT: %{{.*}} = add nsw - %call = tail call i32 @foo(i32 %i) + %call = tail call i32 @foo(i32 %i), !dbg !14 ret i32 %call } @@ -34,9 +34,9 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata) !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 (trunk 265634) (llvm/trunk 265637)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2) !1 = !DIFile(filename: "t.c", directory: "/path/to/tests") - ; CHECK: ![[EMPTY]] = !{} !2 = !{} +!3 = distinct !DISubprogram(name: "caller", scope: !1, file: !1, line: 3, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !0) !4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0) !5 = !DISubroutineType(types: !6) !6 = !{!7, !7} @@ -47,3 +47,4 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata) !11 = !DILocation(line: 2, column: 13, scope: !4) !12 = !DILocation(line: 2, column: 27, scope: !4) !13 = !DILocation(line: 2, column: 18, scope: !4) +!14 = !DILocation(line: 3, scope: !3) diff --git a/test/Transforms/Inline/nodebug.ll b/test/Transforms/Inline/nodebug.ll new file mode 100644 index 00000000000..3678ce858f1 --- /dev/null +++ b/test/Transforms/Inline/nodebug.ll @@ -0,0 +1,36 @@ +; RUN: opt -inline -S -o - < %s | FileCheck %s +; Check that debug info is stripped when inlining into a nodebug function. + +declare void @llvm.dbg.declare(metadata, metadata, metadata) +declare void @llvm.dbg.value(metadata, i64, metadata, metadata) + +define void @foo() !dbg !2 { +entry: + %a = alloca i32 + call void @llvm.dbg.value(metadata i32 0, i64 0, metadata !3, metadata !DIExpression()), !dbg !6 + store i32 0, i32* %a, !dbg !6 + ret void, !dbg !6 +} + +; CHECK: define void @bar() +define void @bar() { +; CHECK-NEXT: entry +entry: +; CHECK-NEXT: alloca i32 +; CHECK-NOT: dbg +; CHECK: ret void + call void @foo() + ret void +} + +!llvm.dbg.cu = !{!0} +!llvm.module.flags = !{!7, !8} + +!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", emissionKind: FullDebug) +!1 = !DIFile(filename: "x.c", directory: "/") +!2 = distinct !DISubprogram(name: "foo", scope: !0, isDefinition: true, unit: !0) +!3 = !DILocalVariable(name: "a", arg: 1, scope: !2, file: !1, line: 1, type: !5) +!5 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!6 = !DILocation(line: 1, scope: !2) +!7 = !{i32 2, !"Dwarf Version", i32 4} +!8 = !{i32 1, !"Debug Info Version", i32 3}