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Roundtrip the inalloca bit on allocas through bitcode 

This was an oversight in the original support.  As it is, I stuffed this
bit into the alignment.  The alignment is stored in log2 form, so it
doesn't need more than 5 bits, given that Value::MaximumAlignment is 1
<< 29.

Reviewers: nicholas

Differential Revision: http://reviews.llvm.org/D3943

llvm-svn: 213118
This commit is contained in:
Reid Kleckner 2014-07-16 01:34:27 +00:00
parent b4db99c76a
commit 56b56ea15b
4 changed files with 34 additions and 5 deletions
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2
llvm/include/llvm/Bitcode/LLVMBitCodes.h
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@ -290,7 +290,7 @@ namespace bitc {
FUNC_CODE_INST_PHI = 16, // PHI: [ty, val0,bb0, ...]
// 17 is unused.
// 18 is unused.
FUNC_CODE_INST_ALLOCA = 19, // ALLOCA: [instty, op, align]
FUNC_CODE_INST_ALLOCA = 19, // ALLOCA: [instty, opty, op, align]
FUNC_CODE_INST_LOAD = 20, // LOAD: [opty, op, align, vol]
// 21 is unused.
// 22 is unused.

8
llvm/lib/Bitcode/Reader/BitcodeReader.cpp
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@ -2889,10 +2889,14 @@ std::error_code BitcodeReader::ParseFunctionBody(Function *F) {
dyn_cast_or_null<PointerType>(getTypeByID(Record[0]));
Type *OpTy = getTypeByID(Record[1]);
Value *Size = getFnValueByID(Record[2], OpTy);
unsigned Align = Record[3];
unsigned AlignRecord = Record[3];
bool InAlloca = AlignRecord & (1 << 5);
unsigned Align = AlignRecord & ((1 << 5) - 1);
if (!Ty || !Size)
return Error(InvalidRecord);
I = new AllocaInst(Ty->getElementType(), Size, (1 << Align) >> 1);
AllocaInst *AI = new AllocaInst(Ty->getElementType(), Size, (1 << Align) >> 1);
AI->setUsedWithInAlloca(InAlloca);
I = AI;
InstructionList.push_back(I);
break;
}

11
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
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@ -1431,13 +1431,20 @@ static void WriteInstruction(const Instruction &I, unsigned InstID,
break;
}
case Instruction::Alloca:
case Instruction::Alloca: {
Code = bitc::FUNC_CODE_INST_ALLOCA;
Vals.push_back(VE.getTypeID(I.getType()));
Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
Vals.push_back(VE.getValueID(I.getOperand(0))); // size.
Vals.push_back(Log2_32(cast<AllocaInst>(I).getAlignment())+1);
const AllocaInst &AI = cast<AllocaInst>(I);
unsigned AlignRecord = Log2_32(AI.getAlignment()) + 1;
assert(Log2_32(Value::MaximumAlignment) + 1 < 1 << 5 &&
"not enough bits for maximum alignment");
assert(AlignRecord < 1 << 5 && "alignment greater than 1 << 64");
AlignRecord |= AI.isUsedWithInAlloca() << 5;
Vals.push_back(AlignRecord);
break;
}
case Instruction::Load:
if (cast<LoadInst>(I).isAtomic()) {

18
llvm/test/Bitcode/inalloca.ll Normal file
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@ -0,0 +1,18 @@
; RUN: llvm-as < %s | llvm-dis | FileCheck %s
; inalloca should roundtrip.
define void @foo(i32* inalloca %args) {
ret void
}
; CHECK-LABEL: define void @foo(i32* inalloca %args)
define void @bar() {
; Use the maximum alignment, since we stuff our bit with alignment.
%args = alloca inalloca i32, align 536870912
call void @foo(i32* inalloca %args)
ret void
}
; CHECK-LABEL: define void @bar() {
; CHECK: %args = alloca inalloca i32, align 536870912
; CHECK: call void @foo(i32* inalloca %args)