From 4e6b8579221c67b83901bcc621d330e7e99a9294 Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Fri, 12 Apr 2019 12:54:52 +0000 Subject: 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 llvm-svn: 358281 --- llvm/lib/CodeGen/PrologEpilogInserter.cpp | 16 +++------------- 1 file changed, 3 insertions(+), 13 deletions(-) (limited to 'llvm/lib/CodeGen/PrologEpilogInserter.cpp') diff --git a/llvm/lib/CodeGen/PrologEpilogInserter.cpp b/llvm/lib/CodeGen/PrologEpilogInserter.cpp index 31f962eba42..67834c8c352 100644 --- a/llvm/lib/CodeGen/PrologEpilogInserter.cpp +++ b/llvm/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; } -- cgit v1.2.3