Polish atomic pointers
Summary:
I didn't realize that we already allowed atomic load/store of pointers,
it was added in 2012 by r162146. This patch updates the documentation
and tightens the verifier by using DataLayout to make sure that the
stored size is byte-sized and power-of-two. DataLayout is also used for
integers, and while I'm here I updated the corresponding code for
cmpxchg and rmw.
See the following discussion for context and upcoming changes to
add floating-point and vector atomics:
https://groups.google.com/forum/#!topic/llvm-dev/Nh0P_E3CRoo/discussion
Reviewers: reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D15512
llvm-svn: 255931
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index a70de2c..1a22d37 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -207,6 +207,8 @@
/// Cache of constants visited in search of ConstantExprs.
SmallPtrSet<const Constant *, 32> ConstantExprVisited;
+ void checkAtomicMemAccessSize(const Module *M, Type *Ty,
+ const Instruction *I);
public:
explicit Verifier(raw_ostream &OS)
: VerifierSupport(OS), Context(nullptr), LandingPadResultTy(nullptr),
@@ -2734,6 +2736,14 @@
}
}
+void Verifier::checkAtomicMemAccessSize(const Module *M, Type *Ty,
+ const Instruction *I) {
+ unsigned Size = M->getDataLayout().getTypeSizeInBits(Ty);
+ Assert(Size >= 8, "atomic memory access' size must be byte-sized", Ty, I);
+ Assert(!(Size & (Size - 1)),
+ "atomic memory access' operand must have a power-of-two size", Ty, I);
+}
+
void Verifier::visitLoadInst(LoadInst &LI) {
PointerType *PTy = dyn_cast<PointerType>(LI.getOperand(0)->getType());
Assert(PTy, "Load operand must be a pointer.", &LI);
@@ -2745,15 +2755,12 @@
"Load cannot have Release ordering", &LI);
Assert(LI.getAlignment() != 0,
"Atomic load must specify explicit alignment", &LI);
- if (!ElTy->isPointerTy()) {
- Assert(ElTy->isIntegerTy() || ElTy->isFloatingPointTy(),
- "atomic load operand must have integer or floating point type!",
- &LI, ElTy);
- unsigned Size = ElTy->getPrimitiveSizeInBits();
- Assert(Size >= 8 && !(Size & (Size - 1)),
- "atomic load operand must be power-of-two byte-sized integer", &LI,
- ElTy);
- }
+ Assert(ElTy->isIntegerTy() || ElTy->isPointerTy() ||
+ ElTy->isFloatingPointTy(),
+ "atomic load operand must have integer, pointer, or floating point "
+ "type!",
+ ElTy, &LI);
+ checkAtomicMemAccessSize(M, ElTy, &LI);
} else {
Assert(LI.getSynchScope() == CrossThread,
"Non-atomic load cannot have SynchronizationScope specified", &LI);
@@ -2775,15 +2782,12 @@
"Store cannot have Acquire ordering", &SI);
Assert(SI.getAlignment() != 0,
"Atomic store must specify explicit alignment", &SI);
- if (!ElTy->isPointerTy()) {
- Assert(ElTy->isIntegerTy() || ElTy->isFloatingPointTy(),
- "atomic store operand must have integer or floating point type!",
- &SI, ElTy);
- unsigned Size = ElTy->getPrimitiveSizeInBits();
- Assert(Size >= 8 && !(Size & (Size - 1)),
- "atomic store operand must be power-of-two byte-sized integer",
- &SI, ElTy);
- }
+ Assert(ElTy->isIntegerTy() || ElTy->isPointerTy() ||
+ ElTy->isFloatingPointTy(),
+ "atomic store operand must have integer, pointer, or floating point "
+ "type!",
+ ElTy, &SI);
+ checkAtomicMemAccessSize(M, ElTy, &SI);
} else {
Assert(SI.getSynchScope() == CrossThread,
"Non-atomic store cannot have SynchronizationScope specified", &SI);
@@ -2830,9 +2834,7 @@
Type *ElTy = PTy->getElementType();
Assert(ElTy->isIntegerTy(), "cmpxchg operand must have integer type!", &CXI,
ElTy);
- unsigned Size = ElTy->getPrimitiveSizeInBits();
- Assert(Size >= 8 && !(Size & (Size - 1)),
- "cmpxchg operand must be power-of-two byte-sized integer", &CXI, ElTy);
+ checkAtomicMemAccessSize(M, ElTy, &CXI);
Assert(ElTy == CXI.getOperand(1)->getType(),
"Expected value type does not match pointer operand type!", &CXI,
ElTy);
@@ -2851,10 +2853,7 @@
Type *ElTy = PTy->getElementType();
Assert(ElTy->isIntegerTy(), "atomicrmw operand must have integer type!",
&RMWI, ElTy);
- unsigned Size = ElTy->getPrimitiveSizeInBits();
- Assert(Size >= 8 && !(Size & (Size - 1)),
- "atomicrmw operand must be power-of-two byte-sized integer", &RMWI,
- ElTy);
+ checkAtomicMemAccessSize(M, ElTy, &RMWI);
Assert(ElTy == RMWI.getOperand(1)->getType(),
"Argument value type does not match pointer operand type!", &RMWI,
ElTy);