Index: include/llvm/IR/DebugInfoMetadata.h =================================================================== --- include/llvm/IR/DebugInfoMetadata.h +++ include/llvm/IR/DebugInfoMetadata.h @@ -2508,6 +2508,9 @@ /// 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 &Ops, int64_t Offset); Index: lib/CodeGen/AsmPrinter/DwarfExpression.cpp =================================================================== --- lib/CodeGen/AsmPrinter/DwarfExpression.cpp +++ lib/CodeGen/AsmPrinter/DwarfExpression.cpp @@ -434,6 +434,10 @@ 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"); } Index: lib/CodeGen/MIRParser/MIParser.cpp =================================================================== --- lib/CodeGen/MIRParser/MIParser.cpp +++ lib/CodeGen/MIRParser/MIParser.cpp @@ -1854,6 +1854,11 @@ 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() + "'"); } Index: lib/CodeGen/PrologEpilogInserter.cpp =================================================================== --- lib/CodeGen/PrologEpilogInserter.cpp +++ lib/CodeGen/PrologEpilogInserter.cpp @@ -1172,12 +1172,22 @@ 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 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; } Index: lib/IR/DebugInfoMetadata.cpp =================================================================== --- lib/IR/DebugInfoMetadata.cpp +++ lib/IR/DebugInfoMetadata.cpp @@ -817,6 +817,7 @@ 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: @@ -873,6 +874,7 @@ 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: @@ -883,6 +885,19 @@ 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::getFragmentInfo(expr_op_iterator Start, expr_op_iterator End) { for (auto I = Start; I != End; ++I) Index: test/CodeGen/X86/prologepilog_deref_size.mir =================================================================== --- /dev/null +++ test/CodeGen/X86/prologepilog_deref_size.mir @@ -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)