[llvm] r358268 - [DebugInfo] DW_OP_deref_size in PrologEpilogInserter.
Hans Wennborg via llvm-commits
llvm-commits at lists.llvm.org
Fri Apr 12 05:54:31 PDT 2019
This caused the compiler to crash when building Chromium. I've
reverted in r358281. See
https://bugs.chromium.org/p/chromium/issues/detail?id=952230 for the
reproducer.
On Fri, Apr 12, 2019 at 10:22 AM Markus Lavin via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
>
> Author: markus
> Date: Fri Apr 12 01:23:55 2019
> New Revision: 358268
>
> URL: http://llvm.org/viewvc/llvm-project?rev=358268&view=rev
> Log:
> [DebugInfo] DW_OP_deref_size in PrologEpilogInserter.
>
> The PrologEpilogInserter need to insert a DW_OP_deref_size before
> prepending a memory location expression to an already implicit
> expression to avoid having the existing expression act on the memory
> address instead of the value behind it.
>
> The reason for using DW_OP_deref_size and not plain DW_OP_deref is that
> big-endian targets need to read the right size as simply truncating a
> larger read would yield the wrong result (LSB bytes are not at the lower
> address).
>
> Differential Revision: https://reviews.llvm.org/D59687
>
> Added:
> llvm/trunk/test/CodeGen/X86/prologepilog_deref_size.mir
> Modified:
> llvm/trunk/include/llvm/IR/DebugInfoMetadata.h
> llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
> llvm/trunk/lib/CodeGen/MIRParser/MIParser.cpp
> llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp
> llvm/trunk/lib/IR/DebugInfoMetadata.cpp
>
> Modified: llvm/trunk/include/llvm/IR/DebugInfoMetadata.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/DebugInfoMetadata.h?rev=358268&r1=358267&r2=358268&view=diff
> ==============================================================================
> --- llvm/trunk/include/llvm/IR/DebugInfoMetadata.h (original)
> +++ llvm/trunk/include/llvm/IR/DebugInfoMetadata.h Fri Apr 12 01:23:55 2019
> @@ -2510,6 +2510,9 @@ public:
> /// Return whether this is a piece of an aggregate variable.
> bool isFragment() const { return getFragmentInfo().hasValue(); }
>
> + /// Return whether this is an implicit location description.
> + bool isImplicit() const;
> +
> /// Append \p Ops with operations to apply the \p Offset.
> static void appendOffset(SmallVectorImpl<uint64_t> &Ops, int64_t Offset);
>
>
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp?rev=358268&r1=358267&r2=358268&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfExpression.cpp Fri Apr 12 01:23:55 2019
> @@ -434,6 +434,10 @@ void DwarfExpression::addExpression(DIEx
> assert(LocationKind != Register);
> emitOp(dwarf::DW_OP_xderef);
> break;
> + case dwarf::DW_OP_deref_size:
> + emitOp(dwarf::DW_OP_deref_size);
> + emitUnsigned(Op->getArg(0));
> + break;
> default:
> llvm_unreachable("unhandled opcode found in expression");
> }
>
> Modified: llvm/trunk/lib/CodeGen/MIRParser/MIParser.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/MIRParser/MIParser.cpp?rev=358268&r1=358267&r2=358268&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/MIRParser/MIParser.cpp (original)
> +++ llvm/trunk/lib/CodeGen/MIRParser/MIParser.cpp Fri Apr 12 01:23:55 2019
> @@ -1854,6 +1854,11 @@ bool MIParser::parseDIExpression(MDNode
> Elements.push_back(Op);
> continue;
> }
> + if (unsigned Enc = dwarf::getAttributeEncoding(Token.stringValue())) {
> + lex();
> + Elements.push_back(Enc);
> + continue;
> + }
> return error(Twine("invalid DWARF op '") + Token.stringValue() + "'");
> }
>
>
> Modified: llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp?rev=358268&r1=358267&r2=358268&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp (original)
> +++ llvm/trunk/lib/CodeGen/PrologEpilogInserter.cpp Fri Apr 12 01:23:55 2019
> @@ -1172,12 +1172,22 @@ void PEI::replaceFrameIndices(MachineBas
> assert(i == 0 && "Frame indices can only appear as the first "
> "operand of a DBG_VALUE machine instruction");
> unsigned Reg;
> + unsigned FrameIdx = MI.getOperand(0).getIndex();
> + unsigned Size = MF.getFrameInfo().getObjectSize(FrameIdx);
> +
> int64_t Offset =
> - TFI->getFrameIndexReference(MF, MI.getOperand(0).getIndex(), Reg);
> + TFI->getFrameIndexReference(MF, FrameIdx, Reg);
> MI.getOperand(0).ChangeToRegister(Reg, false /*isDef*/);
> MI.getOperand(0).setIsDebug();
> - auto *DIExpr = DIExpression::prepend(MI.getDebugExpression(),
> - DIExpression::NoDeref, Offset);
> +
> + const DIExpression *DIExpr = MI.getDebugExpression();
> + // If we already have a Implicit location expression we need to insert
> + // a deref before prepending a Memory location expression.
> + if (DIExpr->isImplicit()) {
> + SmallVector<uint64_t, 2> Ops = {dwarf::DW_OP_deref_size, Size};
> + DIExpr = DIExpression::prependOpcodes(DIExpr, Ops, DIExpression::WithStackValue);
> + }
> + DIExpr = DIExpression::prepend(DIExpr, DIExpression::NoDeref, Offset);
> MI.getOperand(3).setMetadata(DIExpr);
> continue;
> }
>
> Modified: llvm/trunk/lib/IR/DebugInfoMetadata.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/DebugInfoMetadata.cpp?rev=358268&r1=358267&r2=358268&view=diff
> ==============================================================================
> --- llvm/trunk/lib/IR/DebugInfoMetadata.cpp (original)
> +++ llvm/trunk/lib/IR/DebugInfoMetadata.cpp Fri Apr 12 01:23:55 2019
> @@ -833,6 +833,7 @@ unsigned DIExpression::ExprOperand::getS
> case dwarf::DW_OP_LLVM_fragment:
> return 3;
> case dwarf::DW_OP_constu:
> + case dwarf::DW_OP_deref_size:
> case dwarf::DW_OP_plus_uconst:
> return 2;
> default:
> @@ -889,6 +890,7 @@ bool DIExpression::isValid() const {
> case dwarf::DW_OP_shr:
> case dwarf::DW_OP_shra:
> case dwarf::DW_OP_deref:
> + case dwarf::DW_OP_deref_size:
> case dwarf::DW_OP_xderef:
> case dwarf::DW_OP_lit0:
> case dwarf::DW_OP_not:
> @@ -899,6 +901,19 @@ bool DIExpression::isValid() const {
> return true;
> }
>
> +bool DIExpression::isImplicit() const {
> + unsigned N = getNumElements();
> + if (isValid() && N > 0) {
> + switch (getElement(N-1)) {
> + case dwarf::DW_OP_stack_value: return true;
> + case dwarf::DW_OP_LLVM_fragment:
> + return N > 1 && getElement(N-2) == dwarf::DW_OP_stack_value;
> + default: break;
> + }
> + }
> + return false;
> +}
> +
> Optional<DIExpression::FragmentInfo>
> DIExpression::getFragmentInfo(expr_op_iterator Start, expr_op_iterator End) {
> for (auto I = Start; I != End; ++I)
>
> Added: llvm/trunk/test/CodeGen/X86/prologepilog_deref_size.mir
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/prologepilog_deref_size.mir?rev=358268&view=auto
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/prologepilog_deref_size.mir (added)
> +++ llvm/trunk/test/CodeGen/X86/prologepilog_deref_size.mir Fri Apr 12 01:23:55 2019
> @@ -0,0 +1,59 @@
> +# RUN: llc -run-pass=prologepilog -o - %s | FileCheck %s
> +--- |
> + ; ModuleID = 'dbg.opt.ll'
> + source_filename = "dbg.c"
> + 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 uwtable
> + define dso_local zeroext i16 @foo(i16 zeroext %d0, i16 zeroext %d1, i16 zeroext %d2, i16 zeroext %d3, i16 zeroext %d4, i16 zeroext %d5, i16 zeroext %d6, i16 zeroext %d7, i16 zeroext %d8, i16 signext %x) #0 !dbg !7 {
> + entry:
> + call void @llvm.dbg.value(metadata i16 %x, metadata !32, metadata !DIExpression(DW_OP_LLVM_convert, 16, DW_ATE_signed, DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value)), !dbg !34
> + ret i16 %x
> + }
> +
> + ; Function Attrs: nounwind readnone speculatable
> + declare void @llvm.dbg.value(metadata, metadata, metadata) #1
> +
> + attributes #0 = { noinline nounwind uwtable }
> + attributes #1 = { nounwind readnone speculatable }
> +
> + !llvm.dbg.cu = !{!0}
> + !llvm.module.flags = !{!3, !4, !5}
> + !llvm.ident = !{!6}
> +
> + !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 9.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
> + !1 = !DIFile(filename: "dbg.c", 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 9.0.0"}
> + !7 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 2, type: !8, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
> + !8 = !DISubroutineType(types: !9)
> + !9 = !{!10, !10, !10, !10, !10, !10, !10, !10, !10, !10, !10}
> + !10 = !DIDerivedType(tag: DW_TAG_typedef, name: "T", file: !1, line: 1, baseType: !11)
> + !11 = !DIBasicType(name: "signed short", size: 16, encoding: DW_ATE_signed)
> + !32 = !DILocalVariable(name: "y", scope: !7, file: !1, line: 3, type: !33)
> + !33 = !DIBasicType(name: "signed int", size: 32, encoding: DW_ATE_signed)
> + !34 = !DILocation(line: 3, column: 20, scope: !7)
> +
> +...
> +---
> +name: foo
> +tracksRegLiveness: true
> +fixedStack:
> + - { id: 0, type: default, offset: 24, size: 2, alignment: 8, stack-id: 0,
> + isImmutable: true, isAliased: false, callee-saved-register: '', callee-saved-restored: true,
> + debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
> +stack: []
> +constants: []
> +machineFunctionInfo: {}
> +body: |
> + bb.0.entry:
> + renamable $ax = MOV16rm %fixed-stack.0, 1, $noreg, 0, $noreg :: (load 2 from %fixed-stack.0, align 8)
> + DBG_VALUE %fixed-stack.0, 0, !32, !DIExpression(DW_OP_LLVM_convert, 16, DW_ATE_signed, DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value), debug-location !34
> + RET 0, $ax
> +...
> +# CHECK: machineFunctionInfo
> +# CHECK: DIExpression(DW_OP_plus_uconst, {{[0-9]+}}, DW_OP_deref_size, 2, DW_OP_LLVM_convert, 16, DW_ATE_signed, DW_OP_LLVM_convert, 32, DW_ATE_signed, DW_OP_stack_value)
>
>
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