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MS ABI: Implement /volatile:ms

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The /volatile:ms semantics turn volatile loads and stores into atomic
acquire and release operations.  This distinction is important because
volatile memory operations do not form a happens-before relationship
with non-atomic memory.  This means that a volatile store is not
sufficient for implementing a mutex unlock routine.

Differential Revision: http://reviews.llvm.org/D7580

llvm-svn: 229082
This commit is contained in:
David Majnemer
2015-02-13 07:55:47 +00:00
parent 2a903b900d
commit abc482effc
14 changed files with 181 additions and 26 deletions
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8
clang/lib/CodeGen/CGExprAgg.cpp
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@@ -212,7 +212,7 @@ void AggExprEmitter::EmitAggLoadOfLValue(const Expr *E) {
LValue LV = CGF.EmitLValue(E);
// If the type of the l-value is atomic, then do an atomic load.
if (LV.getType()->isAtomicType()) {
if (LV.getType()->isAtomicType() || CGF.LValueIsSuitableForInlineAtomic(LV)) {
CGF.EmitAtomicLoad(LV, E->getExprLoc(), Dest);
return;
}
@@ -865,7 +865,8 @@ void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
LValue LHS = CGF.EmitCheckedLValue(E->getLHS(), CodeGenFunction::TCK_Store);
// That copy is an atomic copy if the LHS is atomic.
if (LHS.getType()->isAtomicType()) {
if (LHS.getType()->isAtomicType() ||
CGF.LValueIsSuitableForInlineAtomic(LHS)) {
CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);
return;
}
@@ -882,7 +883,8 @@ void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
// If we have an atomic type, evaluate into the destination and then
// do an atomic copy.
if (LHS.getType()->isAtomicType()) {
if (LHS.getType()->isAtomicType() ||
CGF.LValueIsSuitableForInlineAtomic(LHS)) {
EnsureDest(E->getRHS()->getType());
Visit(E->getRHS());
CGF.EmitAtomicStore(Dest.asRValue(), LHS, /*isInit*/ false);