From 0366e3e18142466e4dd99d3109d8facd093cedc8 Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Fri, 12 Apr 2019 12:54:52 +0000 Subject: [PATCH] Revert r358268 "[DebugInfo] DW_OP_deref_size in PrologEpilogInserter." It causes clang to crash while building Chromium. See https://crbug.com/952230 for reproducer. > 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 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358281 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/IR/DebugInfoMetadata.h | 3 - lib/CodeGen/AsmPrinter/DwarfExpression.cpp | 4 -- lib/CodeGen/MIRParser/MIParser.cpp | 5 -- lib/CodeGen/PrologEpilogInserter.cpp | 16 +----- lib/IR/DebugInfoMetadata.cpp | 15 ----- test/CodeGen/X86/prologepilog_deref_size.mir | 59 -------------------- 6 files changed, 3 insertions(+), 99 deletions(-) delete mode 100644 test/CodeGen/X86/prologepilog_deref_size.mir diff --git a/include/llvm/IR/DebugInfoMetadata.h b/include/llvm/IR/DebugInfoMetadata.h index 357074a3649..2ec8de14d66 100644 --- a/include/llvm/IR/DebugInfoMetadata.h +++ b/include/llvm/IR/DebugInfoMetadata.h @@ -2510,9 +2510,6 @@ 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 &Ops, int64_t Offset); diff --git a/lib/CodeGen/AsmPrinter/DwarfExpression.cpp b/lib/CodeGen/AsmPrinter/DwarfExpression.cpp index 48f8addd031..41fa45f2507 100644 --- a/lib/CodeGen/AsmPrinter/DwarfExpression.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfExpression.cpp @@ -434,10 +434,6 @@ void DwarfExpression::addExpression(DIExpressionCursor &&ExprCursor, 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"); } diff --git a/lib/CodeGen/MIRParser/MIParser.cpp b/lib/CodeGen/MIRParser/MIParser.cpp index d414b6a0b4b..971944be2f9 100644 --- a/lib/CodeGen/MIRParser/MIParser.cpp +++ b/lib/CodeGen/MIRParser/MIParser.cpp @@ -1854,11 +1854,6 @@ bool MIParser::parseDIExpression(MDNode *&Expr) { 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() + "'"); } diff --git a/lib/CodeGen/PrologEpilogInserter.cpp b/lib/CodeGen/PrologEpilogInserter.cpp index 31f962eba42..67834c8c352 100644 --- a/lib/CodeGen/PrologEpilogInserter.cpp +++ b/lib/CodeGen/PrologEpilogInserter.cpp @@ -1172,22 +1172,12 @@ void PEI::replaceFrameIndices(MachineBasicBlock *BB, MachineFunction &MF, 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, FrameIdx, Reg); + TFI->getFrameIndexReference(MF, MI.getOperand(0).getIndex(), Reg); MI.getOperand(0).ChangeToRegister(Reg, false /*isDef*/); MI.getOperand(0).setIsDebug(); - - 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); + auto *DIExpr = DIExpression::prepend(MI.getDebugExpression(), + DIExpression::NoDeref, Offset); MI.getOperand(3).setMetadata(DIExpr); continue; } diff --git a/lib/IR/DebugInfoMetadata.cpp b/lib/IR/DebugInfoMetadata.cpp index 4ef38b6f7fe..7158e5764fa 100644 --- a/lib/IR/DebugInfoMetadata.cpp +++ b/lib/IR/DebugInfoMetadata.cpp @@ -833,7 +833,6 @@ unsigned DIExpression::ExprOperand::getSize() const { 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: @@ -890,7 +889,6 @@ 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: @@ -901,19 +899,6 @@ 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::getFragmentInfo(expr_op_iterator Start, expr_op_iterator End) { for (auto I = Start; I != End; ++I) diff --git a/test/CodeGen/X86/prologepilog_deref_size.mir b/test/CodeGen/X86/prologepilog_deref_size.mir deleted file mode 100644 index 0b0ea5d881e..00000000000 --- a/test/CodeGen/X86/prologepilog_deref_size.mir +++ /dev/null @@ -1,59 +0,0 @@ -# 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) -- 2.50.1