From c451c9ef50b7b3df260e709a9dcd6324356d57a2 Mon Sep 17 00:00:00 2001 From: Petar Jovanovic Date: Mon, 24 Sep 2018 10:01:24 +0000 Subject: [PATCH] [deadargelim] Update dbg.value of 'unused' parameters MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit DeadArgElim pass marks unused function arguments as ‘undef’ without updating existing dbg.values referring to it. As a consequence the debug info metadata in the final executable was wrong. Patch by Djordje Todorovic. Differential Revision: https://reviews.llvm.org/D51968 llvm-svn: 342871 --- .../IPO/DeadArgumentElimination.cpp | 11 ++- .../DeadArgElim/dbginfo-update-dbgval.ll | 86 +++++++++++++++++++ 2 files changed, 94 insertions(+), 3 deletions(-) create mode 100644 llvm/test/Transforms/DeadArgElim/dbginfo-update-dbgval.ll diff --git a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp index cd2bd734eb26..0cf238b5d606 100644 --- a/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp +++ b/llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp @@ -289,16 +289,21 @@ bool DeadArgumentEliminationPass::RemoveDeadArgumentsFromCallers(Function &Fn) { return false; SmallVector UnusedArgs; + bool Changed = false; + for (Argument &Arg : Fn.args()) { - if (!Arg.hasSwiftErrorAttr() && Arg.use_empty() && !Arg.hasByValOrInAllocaAttr()) + if (!Arg.hasSwiftErrorAttr() && Arg.use_empty() && !Arg.hasByValOrInAllocaAttr()) { + if (Arg.isUsedByMetadata()) { + Arg.replaceAllUsesWith(UndefValue::get(Arg.getType())); + Changed = true; + } UnusedArgs.push_back(Arg.getArgNo()); + } } if (UnusedArgs.empty()) return false; - bool Changed = false; - for (Use &U : Fn.uses()) { CallSite CS(U.getUser()); if (!CS || !CS.isCallee(&U)) diff --git a/llvm/test/Transforms/DeadArgElim/dbginfo-update-dbgval.ll b/llvm/test/Transforms/DeadArgElim/dbginfo-update-dbgval.ll new file mode 100644 index 000000000000..c49c4f46c6a9 --- /dev/null +++ b/llvm/test/Transforms/DeadArgElim/dbginfo-update-dbgval.ll @@ -0,0 +1,86 @@ +; RUN: opt -deadargelim -S < %s | FileCheck %s +;test.c +;int s; +; +;void f2(int k) __attribute__((noinline)) { +; s++; +; k = s; +;} +; +;void f() __attribute__((noinline)) { +; f2(4); +;} +; +;int main() +;{ +; f(); +; return 0; +;} + +target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" + +@s = common dso_local local_unnamed_addr global i32 0, align 4, !dbg !0 + +; Function Attrs: noinline nounwind uwtable +define dso_local void @f2(i32 %k) local_unnamed_addr !dbg !11 { +entry: +; CHECK: call void @llvm.dbg.value(metadata i32 undef, metadata !15, metadata !DIExpression()), !dbg !16 + call void @llvm.dbg.value(metadata i32 %k, metadata !15, metadata !DIExpression()), !dbg !16 + %0 = load i32, i32* @s, align 4, !dbg !17 + %inc = add nsw i32 %0, 1, !dbg !17 + store i32 %inc, i32* @s, align 4, !dbg !17 + call void @llvm.dbg.value(metadata i32* @s, metadata !15, metadata !DIExpression(DW_OP_deref)), !dbg !16 + ret void, !dbg !18 +} + +; Function Attrs: noinline nounwind uwtable +define dso_local void @f() local_unnamed_addr !dbg !19 { +entry: +; CHECK: tail call void @f2(i32 undef), !dbg !22 + tail call void @f2(i32 4), !dbg !22 + ret void, !dbg !23 +} + +; Function Attrs: nounwind uwtable +define dso_local i32 @main() local_unnamed_addr !dbg !24 { +entry: + tail call void @f(), !dbg !27 + ret i32 0, !dbg !28 +} + +; Function Attrs: nounwind readnone speculatable +declare void @llvm.dbg.value(metadata, metadata, metadata) + +!llvm.dbg.cu = !{!2} +!llvm.module.flags = !{!7, !8, !9} +!llvm.ident = !{!10} + +!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression()) +!1 = distinct !DIGlobalVariable(name: "s", scope: !2, file: !3, line: 1, type: !6, isLocal: false, isDefinition: true) +!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang version 8.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5) +!3 = !DIFile(filename: "test.c", directory: "/dir") +!4 = !{} +!5 = !{!0} +!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed) +!7 = !{i32 2, !"Dwarf Version", i32 4} +!8 = !{i32 2, !"Debug Info Version", i32 3} +!9 = !{i32 1, !"wchar_size", i32 4} +!10 = !{!"clang version 7.0.0"} +!11 = distinct !DISubprogram(name: "f2", scope: !3, file: !3, line: 3, type: !12, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !2, retainedNodes: !14) +!12 = !DISubroutineType(types: !13) +!13 = !{null, !6} +!14 = !{!15} +!15 = !DILocalVariable(name: "k", arg: 1, scope: !11, file: !3, line: 3, type: !6) +!16 = !DILocation(line: 3, column: 13, scope: !11) +!17 = !DILocation(line: 4, column: 3, scope: !11) +!18 = !DILocation(line: 6, column: 1, scope: !11) +!19 = distinct !DISubprogram(name: "f", scope: !3, file: !3, line: 8, type: !20, isLocal: false, isDefinition: true, scopeLine: 8, isOptimized: true, unit: !2, retainedNodes: !4) +!20 = !DISubroutineType(types: !21) +!21 = !{null} +!22 = !DILocation(line: 9, column: 2, scope: !19) +!23 = !DILocation(line: 10, column: 1, scope: !19) +!24 = distinct !DISubprogram(name: "main", scope: !3, file: !3, line: 12, type: !25, isLocal: false, isDefinition: true, scopeLine: 12, isOptimized: true, unit: !2, retainedNodes: !4) +!25 = !DISubroutineType(types: !26) +!26 = !{!6} +!27 = !DILocation(line: 13, column: 2, scope: !24) +!28 = !DILocation(line: 14, column: 2, scope: !24)