P0145R3 (C++17 evaluation order tweaks): evaluate the right-hand side of

assignment and compound-assignment operators before the left-hand side. (Even
if it's an overloaded operator.)

This completes the implementation of P0145R3 + P0400R0 for all targets except
Windows, where the evaluation order guarantees for <<, >>, and ->* are
unimplementable as the ABI requires the function arguments are evaluated from
right to left (because parameter destructors are run from left to right in the
callee).

llvm-svn: 282556

1 files changed, 8 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index 7820fda6ba5..378a2562f8a 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -2867,7 +2867,8 @@ public:
   EmitCXXMemberOrOperatorCall(const CXXMethodDecl *MD, llvm::Value *Callee,
                               ReturnValueSlot ReturnValue, llvm::Value *This,
                               llvm::Value *ImplicitParam,
-                              QualType ImplicitParamTy, const CallExpr *E);
+                              QualType ImplicitParamTy, const CallExpr *E,
+                              CallArgList *RtlArgs);
   RValue EmitCXXDestructorCall(const CXXDestructorDecl *DD, llvm::Value *Callee,
                                llvm::Value *This, llvm::Value *ImplicitParam,
                                QualType ImplicitParamTy, const CallExpr *E,
@@ -3322,7 +3323,8 @@ public:
   void EmitCallArgs(CallArgList &Args, const T *CallArgTypeInfo,
                     llvm::iterator_range<CallExpr::const_arg_iterator> ArgRange,
                     const FunctionDecl *CalleeDecl = nullptr,
-                    unsigned ParamsToSkip = 0) {
+                    unsigned ParamsToSkip = 0,
+                    bool ForceRightToLeftEvaluation = false) {
     SmallVector<QualType, 16> ArgTypes;
     CallExpr::const_arg_iterator Arg = ArgRange.begin();
 
@@ -3362,13 +3364,15 @@ public:
     for (auto *A : llvm::make_range(Arg, ArgRange.end()))
       ArgTypes.push_back(getVarArgType(A));
 
-    EmitCallArgs(Args, ArgTypes, ArgRange, CalleeDecl, ParamsToSkip);
+    EmitCallArgs(Args, ArgTypes, ArgRange, CalleeDecl, ParamsToSkip,
+                 ForceRightToLeftEvaluation);
   }
 
   void EmitCallArgs(CallArgList &Args, ArrayRef<QualType> ArgTypes,
                     llvm::iterator_range<CallExpr::const_arg_iterator> ArgRange,
                     const FunctionDecl *CalleeDecl = nullptr,
-                    unsigned ParamsToSkip = 0);
+                    unsigned ParamsToSkip = 0,
+                    bool ForceRightToLeftEvaluation = false);
 
   /// EmitPointerWithAlignment - Given an expression with a pointer
   /// type, emit the value and compute our best estimate of the