Some improvements to the handling of C11 atomic types:
- Add atomic-to/from-nonatomic cast types
- Emit atomic operations for arithmetic on atomic types
- Emit non-atomic stores for initialisation of atomic types, but atomic stores and loads for every other store / load
- Add a __atomic_init() intrinsic which does a non-atomic store to an _Atomic() type. This is needed for the corresponding C11 stdatomic.h function.
- Enables the relevant __has_feature() checks. The feature isn't 100% complete yet, but it's done enough that we want people testing it.
Still to do:
- Make the arithmetic operations on atomic types (e.g. Atomic(int) foo = 1; foo++;) use the correct LLVM intrinsic if one exists, not a loop with a cmpxchg.
- Add a signal fence builtin
- Properly set the fenv state in atomic operations on floating point values
- Correctly handle things like _Atomic(_Complex double) which are too large for an atomic cmpxchg on some platforms (this requires working out what 'correctly' means in this context)
- Fix the many remaining corner cases
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148242 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index c6ba65c..43ab116 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -764,6 +764,9 @@
Load->setAlignment(Alignment);
if (TBAAInfo)
CGM.DecorateInstruction(Load, TBAAInfo);
+ // If this is an atomic type, all normal reads must be atomic
+ if (Ty->isAtomicType())
+ Load->setAtomic(llvm::SequentiallyConsistent);
return EmitFromMemory(Load, Ty);
}
@@ -800,7 +803,8 @@
void CodeGenFunction::EmitStoreOfScalar(llvm::Value *Value, llvm::Value *Addr,
bool Volatile, unsigned Alignment,
QualType Ty,
- llvm::MDNode *TBAAInfo) {
+ llvm::MDNode *TBAAInfo,
+ bool isInit) {
Value = EmitToMemory(Value, Ty);
llvm::StoreInst *Store = Builder.CreateStore(Value, Addr, Volatile);
@@ -808,12 +812,15 @@
Store->setAlignment(Alignment);
if (TBAAInfo)
CGM.DecorateInstruction(Store, TBAAInfo);
+ if (!isInit && Ty->isAtomicType())
+ Store->setAtomic(llvm::SequentiallyConsistent);
}
-void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue) {
+void CodeGenFunction::EmitStoreOfScalar(llvm::Value *value, LValue lvalue,
+ bool isInit) {
EmitStoreOfScalar(value, lvalue.getAddress(), lvalue.isVolatile(),
lvalue.getAlignment().getQuantity(), lvalue.getType(),
- lvalue.getTBAAInfo());
+ lvalue.getTBAAInfo(), isInit);
}
/// EmitLoadOfLValue - Given an expression that represents a value lvalue, this
@@ -961,7 +968,7 @@
/// EmitStoreThroughLValue - Store the specified rvalue into the specified
/// lvalue, where both are guaranteed to the have the same type, and that type
/// is 'Ty'.
-void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst) {
+void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst, bool isInit) {
if (!Dst.isSimple()) {
if (Dst.isVectorElt()) {
// Read/modify/write the vector, inserting the new element.
@@ -1041,7 +1048,7 @@
}
assert(Src.isScalar() && "Can't emit an agg store with this method");
- EmitStoreOfScalar(Src.getScalarVal(), Dst);
+ EmitStoreOfScalar(Src.getScalarVal(), Dst, isInit);
}
void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
@@ -2052,6 +2059,11 @@
case CK_Dependent:
llvm_unreachable("dependent cast kind in IR gen!");
+
+ // These two casts are currently treated as no-ops, although they could
+ // potentially be real operations depending on the target's ABI.
+ case CK_NonAtomicToAtomic:
+ case CK_AtomicToNonAtomic:
case CK_NoOp:
case CK_LValueToRValue:
@@ -2541,6 +2553,7 @@
case AtomicExpr::CmpXchgWeak:
case AtomicExpr::CmpXchgStrong:
case AtomicExpr::Store:
+ case AtomicExpr::Init:
case AtomicExpr::Load: assert(0 && "Already handled!");
case AtomicExpr::Add: Op = llvm::AtomicRMWInst::Add; break;
case AtomicExpr::Sub: Op = llvm::AtomicRMWInst::Sub; break;
@@ -2588,8 +2601,20 @@
getContext().getTargetInfo().getMaxAtomicInlineWidth();
bool UseLibcall = (Size != Align || Size > MaxInlineWidth);
+
+
llvm::Value *Ptr, *Order, *OrderFail = 0, *Val1 = 0, *Val2 = 0;
Ptr = EmitScalarExpr(E->getPtr());
+
+ if (E->getOp() == AtomicExpr::Init) {
+ assert(!Dest && "Init does not return a value");
+ Val1 = EmitScalarExpr(E->getVal1());
+ llvm::StoreInst *Store = Builder.CreateStore(Val1, Ptr);
+ Store->setAlignment(Size);
+ Store->setVolatile(E->isVolatile());
+ return RValue::get(0);
+ }
+
Order = EmitScalarExpr(E->getOrder());
if (E->isCmpXChg()) {
Val1 = EmitScalarExpr(E->getVal1());
@@ -2703,7 +2728,7 @@
// enforce that in general.
break;
}
- if (E->getOp() == AtomicExpr::Store)
+ if (E->getOp() == AtomicExpr::Store || E->getOp() == AtomicExpr::Init)
return RValue::get(0);
return ConvertTempToRValue(*this, E->getType(), OrigDest);
}