From 2a661cd062625ce6155c465d4baab8ef7d99becd Mon Sep 17 00:00:00 2001 From: David Blaikie Date: Tue, 28 Apr 2015 04:30:29 +0000 Subject: [opaque pointer type] Encode the pointee type in the bitcode for 'cmpxchg' As a space optimization, this instruction would just encode the pointer type of the first operand and use the knowledge that the second and third operands would be of the pointee type of the first. When typed pointers go away, this assumption will no longer be available - so encode the type of the second operand explicitly and rely on that for the third. Test case added to demonstrate the backwards compatibility concern, which only comes up when the definition of the second operand comes after the use (hence the weird basic block sequence) - at which point the type needs to be explicitly encoded in the bitcode and the record length changes to accommodate this. llvm-svn: 235966 --- llvm/lib/Bitcode/Reader/BitcodeReader.cpp | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'llvm/lib/Bitcode/Reader/BitcodeReader.cpp') diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp index 1e9a8eb7fd1..cc554a91bea 100644 --- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp +++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp @@ -4146,17 +4146,20 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) { InstructionList.push_back(I); break; } + case bitc::FUNC_CODE_INST_CMPXCHG_OLD: case bitc::FUNC_CODE_INST_CMPXCHG: { // CMPXCHG:[ptrty, ptr, cmp, new, vol, successordering, synchscope, // failureordering?, isweak?] unsigned OpNum = 0; Value *Ptr, *Cmp, *New; if (getValueTypePair(Record, OpNum, NextValueNo, Ptr) || - popValue(Record, OpNum, NextValueNo, - cast(Ptr->getType())->getElementType(), Cmp) || - popValue(Record, OpNum, NextValueNo, - cast(Ptr->getType())->getElementType(), New) || - (Record.size() < OpNum + 3 || Record.size() > OpNum + 5)) + (BitCode == bitc::FUNC_CODE_INST_CMPXCHG + ? getValueTypePair(Record, OpNum, NextValueNo, Cmp) + : popValue(Record, OpNum, NextValueNo, + cast(Ptr->getType())->getElementType(), + Cmp)) || + popValue(Record, OpNum, NextValueNo, Cmp->getType(), New) || + Record.size() < OpNum + 3 || Record.size() > OpNum + 5) return Error("Invalid record"); AtomicOrdering SuccessOrdering = GetDecodedOrdering(Record[OpNum+1]); if (SuccessOrdering == NotAtomic || SuccessOrdering == Unordered) -- cgit v1.2.3