Preserve exceptions information during calls code generation.

This patch changes the generation of CGFunctionInfo to contain 
the FunctionProtoType if it is available. This enables the code 
generation for call instructions to look into this type for 
exception information and therefore generate better quality 
IR - it will not create invoke instructions for functions that 
are know not to throw.

llvm-svn: 253926

1 files changed, 12 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index a3f863fc0af..c2db7287d61 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -3741,12 +3741,21 @@ LValue CodeGenFunction::EmitStmtExprLValue(const StmtExpr *E) {
 
 RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
                                  const CallExpr *E, ReturnValueSlot ReturnValue,
-                                 const Decl *TargetDecl, llvm::Value *Chain) {
+                                 CGCalleeInfo CalleeInfo, llvm::Value *Chain) {
   // Get the actual function type. The callee type will always be a pointer to
   // function type or a block pointer type.
   assert(CalleeType->isFunctionPointerType() &&
          "Call must have function pointer type!");
 
+  // Preserve the non-canonical function type because things like exception
+  // specifications disappear in the canonical type. That information is useful
+  // to drive the generation of more accurate code for this call later on.
+  const FunctionProtoType *NonCanonicalFTP = CalleeType->getAs<PointerType>()
+                                                 ->getPointeeType()
+                                                 ->getAs<FunctionProtoType>();
+
+  const Decl *TargetDecl = CalleeInfo.getCalleeDecl();
+
   if (const FunctionDecl *FD = dyn_cast_or_null<FunctionDecl>(TargetDecl))
     // We can only guarantee that a function is called from the correct
     // context/function based on the appropriate target attributes,
@@ -3867,7 +3876,8 @@ RValue CodeGenFunction::EmitCall(QualType CalleeType, llvm::Value *Callee,
     Callee = Builder.CreateBitCast(Callee, CalleeTy, "callee.knr.cast");
   }
 
-  return EmitCall(FnInfo, Callee, ReturnValue, Args, TargetDecl);
+  return EmitCall(FnInfo, Callee, ReturnValue, Args,
+                  CGCalleeInfo(NonCanonicalFTP, TargetDecl));
 }
 
 LValue CodeGenFunction::