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

1 files changed, 7 insertions, 1 deletions

diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 90ad03755b..77c5717d24 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -277,6 +277,8 @@ Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
     return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Load);
   case Builtin::BI__atomic_store:
     return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Store);
+  case Builtin::BI__atomic_init:
+    return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Init);
   case Builtin::BI__atomic_exchange:
     return SemaAtomicOpsOverloaded(move(TheCallResult), AtomicExpr::Xchg);
   case Builtin::BI__atomic_compare_exchange_strong:
@@ -538,6 +540,8 @@ Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, AtomicExpr::AtomicOp Op)
     NumVals = 2;
     NumOrders = 2;
   }
+  if (Op == AtomicExpr::Init)
+    NumOrders = 0;
 
   if (TheCall->getNumArgs() < NumVals+NumOrders+1) {
     Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args)
@@ -600,7 +604,7 @@ Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, AtomicExpr::AtomicOp Op)
   }
 
   QualType ResultType = ValType;
-  if (Op == AtomicExpr::Store)
+  if (Op == AtomicExpr::Store || Op == AtomicExpr::Init)
     ResultType = Context.VoidTy;
   else if (Op == AtomicExpr::CmpXchgWeak || Op == AtomicExpr::CmpXchgStrong)
     ResultType = Context.BoolTy;
@@ -641,6 +645,8 @@ Sema::SemaAtomicOpsOverloaded(ExprResult TheCallResult, AtomicExpr::AtomicOp Op)
   SubExprs.push_back(Ptr);
   if (Op == AtomicExpr::Load) {
     SubExprs.push_back(TheCall->getArg(1)); // Order
+  } else if (Op == AtomicExpr::Init) {
+    SubExprs.push_back(TheCall->getArg(1)); // Val1
   } else if (Op != AtomicExpr::CmpXchgWeak && Op != AtomicExpr::CmpXchgStrong) {
     SubExprs.push_back(TheCall->getArg(2)); // Order
     SubExprs.push_back(TheCall->getArg(1)); // Val1