[llvm] r235966 - [opaque pointer type] Encode the pointee type in the bitcode for 'cmpxchg'
David Blaikie
dblaikie at gmail.com
Mon Apr 27 21:30:30 PDT 2015
Author: dblaikie
Date: Mon Apr 27 23:30:29 2015
New Revision: 235966
URL: http://llvm.org/viewvc/llvm-project?rev=235966&view=rev
Log:
[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.
Added:
llvm/trunk/test/Bitcode/cmpxchg.3.6.ll
llvm/trunk/test/Bitcode/cmpxchg.3.6.ll.bc
Modified:
llvm/trunk/include/llvm/Bitcode/LLVMBitCodes.h
llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp
Modified: llvm/trunk/include/llvm/Bitcode/LLVMBitCodes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Bitcode/LLVMBitCodes.h?rev=235966&r1=235965&r2=235966&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Bitcode/LLVMBitCodes.h (original)
+++ llvm/trunk/include/llvm/Bitcode/LLVMBitCodes.h Mon Apr 27 23:30:29 2015
@@ -336,7 +336,7 @@ namespace bitc {
FUNC_CODE_DEBUG_LOC = 35, // DEBUG_LOC: [Line,Col,ScopeVal, IAVal]
FUNC_CODE_INST_FENCE = 36, // FENCE: [ordering, synchscope]
- FUNC_CODE_INST_CMPXCHG = 37, // CMPXCHG: [ptrty,ptr,cmp,new, align, vol,
+ FUNC_CODE_INST_CMPXCHG_OLD = 37, // CMPXCHG: [ptrty,ptr,cmp,new, align, vol,
// ordering, synchscope]
FUNC_CODE_INST_ATOMICRMW = 38, // ATOMICRMW: [ptrty,ptr,val, operation,
// align, vol,
@@ -350,6 +350,8 @@ namespace bitc {
FUNC_CODE_INST_GEP = 43, // GEP: [inbounds, n x operands]
FUNC_CODE_INST_STORE = 44, // STORE: [ptrty,ptr,valty,val, align, vol]
FUNC_CODE_INST_STOREATOMIC = 45, // STORE: [ptrty,ptr,val, align, vol
+ FUNC_CODE_INST_CMPXCHG = 46, // CMPXCHG: [ptrty,ptr,valty,cmp,new, align,
+ // vol,ordering,synchscope]
};
enum UseListCodes {
Modified: llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp?rev=235966&r1=235965&r2=235966&view=diff
==============================================================================
--- llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp (original)
+++ llvm/trunk/lib/Bitcode/Reader/BitcodeReader.cpp Mon Apr 27 23:30:29 2015
@@ -4146,17 +4146,20 @@ std::error_code BitcodeReader::ParseFunc
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<PointerType>(Ptr->getType())->getElementType(), Cmp) ||
- popValue(Record, OpNum, NextValueNo,
- cast<PointerType>(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<PointerType>(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)
Modified: llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp?rev=235966&r1=235965&r2=235966&view=diff
==============================================================================
--- llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp (original)
+++ llvm/trunk/lib/Bitcode/Writer/BitcodeWriter.cpp Mon Apr 27 23:30:29 2015
@@ -1917,7 +1917,7 @@ static void WriteInstruction(const Instr
case Instruction::AtomicCmpXchg:
Code = bitc::FUNC_CODE_INST_CMPXCHG;
PushValueAndType(I.getOperand(0), InstID, Vals, VE); // ptrty + ptr
- pushValue(I.getOperand(1), InstID, Vals, VE); // cmp.
+ PushValueAndType(I.getOperand(1), InstID, Vals, VE); // cmp.
pushValue(I.getOperand(2), InstID, Vals, VE); // newval.
Vals.push_back(cast<AtomicCmpXchgInst>(I).isVolatile());
Vals.push_back(GetEncodedOrdering(
Added: llvm/trunk/test/Bitcode/cmpxchg.3.6.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Bitcode/cmpxchg.3.6.ll?rev=235966&view=auto
==============================================================================
--- llvm/trunk/test/Bitcode/cmpxchg.3.6.ll (added)
+++ llvm/trunk/test/Bitcode/cmpxchg.3.6.ll Mon Apr 27 23:30:29 2015
@@ -0,0 +1,13 @@
+; RUN: llvm-dis < %s.bc | FileCheck %s
+
+define void @f2(i32* %x, i32 %y.orig, i32 %z) {
+entry:
+ br label %a
+b:
+ cmpxchg i32* %x, i32 %y, i32 %z acquire acquire
+; CHECK: cmpxchg i32* %x, i32 %y, i32 %z acquire acquire
+ ret void
+a:
+ %y = add i32 %y.orig, 1
+ br label %a
+}
Added: llvm/trunk/test/Bitcode/cmpxchg.3.6.ll.bc
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Bitcode/cmpxchg.3.6.ll.bc?rev=235966&view=auto
==============================================================================
Binary files llvm/trunk/test/Bitcode/cmpxchg.3.6.ll.bc (added) and llvm/trunk/test/Bitcode/cmpxchg.3.6.ll.bc Mon Apr 27 23:30:29 2015 differ
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