[opaque pointer types] Make EmitCall pass Function Types to CreateCall/Invoke.

[jyknight]

Summary

Also, remove the getFunctionType() function from CGCallee, since it
accesses the pointee type of the value. The only use was in EmitCall,
so just inline it into the debug assertion.

This is the last of the changes for Call and Invoke in clang.

[dblaikie]

Cool, thanks!

lib/CodeGen/CGCall.h

public:
     GlobalDecl getVirtualMethodDecl() const {
       assert(isVirtual());
       return VirtualInfo.MD;
     }
     Address getThisAddress() const {
       assert(isVirtual());
       return VirtualInfo.Addr;
     }
-
-    llvm::FunctionType *getFunctionType() const {
-      if (isVirtual())
-        return VirtualInfo.FTy;
-      return cast<llvm::FunctionType>(
-          getFunctionPointer()->getType()->getPointerElementType());
+    llvm::FunctionType *getVirtualFunctionType() const {
+      assert(isVirtual());
     }
 
     /// If this is a delayed callee computation of some sort, prepare
     /// a concrete callee.
     CGCallee prepareConcreteCallee(CodeGenFunction &CGF) const;
   };
 
   struct CallArg {

lib/CodeGen/CGCall.cpp

RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
 
   assert(Callee.isOrdinary() || Callee.isVirtual());
 
   // Handle struct-return functions by passing a pointer to the
   // location that we would like to return into.
   QualType RetTy = CallInfo.getReturnType();
   const ABIArgInfo &RetAI = CallInfo.getReturnInfo();
 
-  llvm::FunctionType *IRFuncTy = Callee.getFunctionType();
+  llvm::FunctionType *IRFuncTy = getTypes().GetFunctionType(CallInfo);
 
 #ifndef NDEBUG
   if (!(CallInfo.isVariadic() && CallInfo.getArgStruct())) {
     // For an inalloca varargs function, we don't expect CallInfo to match the
     // function pointer's type, because the inalloca struct a will have extra
     // fields in it for the varargs parameters.  Code later in this function
     // bitcasts the function pointer to the type derived from CallInfo.
     //
     // In other cases, we assert that the types match up (until pointers stop
     // having pointee types).
-    llvm::FunctionType *IRFuncTyFromInfo = getTypes().GetFunctionType(CallInfo);
-    assert(IRFuncTy == IRFuncTyFromInfo);
+    llvm::Type *TypeFromVal;
+    if (Callee.isVirtual())
+      TypeFromVal = Callee.getVirtualFunctionType();
+    else
+      TypeFromVal =
+          Callee.getFunctionPointer()->getType()->getPointerElementType();
+    assert(IRFuncTy == TypeFromVal);
   }
 #endif
 
   // 1. Set up the arguments.
 
   // If we're using inalloca, insert the allocation after the stack save.
   // FIXME: Do this earlier rather than hacking it in here!
   Address ArgMemory = Address::invalid();
#endif
   if (ArgMemory.isValid()) {
     llvm::Value *Arg = ArgMemory.getPointer();
     if (CallInfo.isVariadic()) {
       // When passing non-POD arguments by value to variadic functions, we will
       // end up with a variadic prototype and an inalloca call site.  In such
       // cases, we can't do any parameter mismatch checks.  Give up and bitcast
       // the callee.
       unsigned CalleeAS = CalleePtr->getType()->getPointerAddressSpace();
-      auto FnTy = getTypes().GetFunctionType(CallInfo)->getPointerTo(CalleeAS);
-      CalleePtr = Builder.CreateBitCast(CalleePtr, FnTy);
+      CalleePtr =
+          Builder.CreateBitCast(CalleePtr, IRFuncTy->getPointerTo(CalleeAS));
     } else {
       llvm::Type *LastParamTy =
           IRFuncTy->getParamType(IRFuncTy->getNumParams() - 1);
       if (Arg->getType() != LastParamTy) {
 #ifndef NDEBUG
         // Assert that these structs have equivalent element types.
         llvm::StructType *FullTy = CallInfo.getArgStruct();
         llvm::StructType *DeclaredTy = cast<llvm::StructType>(
#endif
   // 2. Prepare the function pointer.
 
   // If the callee is a bitcast of a non-variadic function to have a
   // variadic function pointer type, check to see if we can remove the
   // bitcast.  This comes up with unprototyped functions.
   //
   // This makes the IR nicer, but more importantly it ensures that we
   // can inline the function at -O0 if it is marked always_inline.
-  auto simplifyVariadicCallee = [](llvm::Value *Ptr) -> llvm::Value* {
-    llvm::FunctionType *CalleeFT =
-      cast<llvm::FunctionType>(Ptr->getType()->getPointerElementType());
+  auto simplifyVariadicCallee = [](llvm::FunctionType *CalleeFT,
+                                   llvm::Value *Ptr) -> llvm::Function * {
     if (!CalleeFT->isVarArg())
-      return Ptr;
+      return nullptr;
 
-    llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Ptr);
-    if (!CE || CE->getOpcode() != llvm::Instruction::BitCast)
-      return Ptr;
+    // Get underlying value if it's a bitcast
+    if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(Ptr)) {
+      if (CE->getOpcode() == llvm::Instruction::BitCast)
+        Ptr = CE->getOperand(0);
+    }
 
-    llvm::Function *OrigFn = dyn_cast<llvm::Function>(CE->getOperand(0));
+    llvm::Function *OrigFn = dyn_cast<llvm::Function>(Ptr);
     if (!OrigFn)
-      return Ptr;
+      return nullptr;
 
     llvm::FunctionType *OrigFT = OrigFn->getFunctionType();
 
     // If the original type is variadic, or if any of the component types
     // disagree, we cannot remove the cast.
     if (OrigFT->isVarArg() ||
         OrigFT->getNumParams() != CalleeFT->getNumParams() ||
         OrigFT->getReturnType() != CalleeFT->getReturnType())
-      return Ptr;
+      return nullptr;
 
     for (unsigned i = 0, e = OrigFT->getNumParams(); i != e; ++i)
       if (OrigFT->getParamType(i) != CalleeFT->getParamType(i))
-        return Ptr;
+        return nullptr;
 
     return OrigFn;
   };
-  CalleePtr = simplifyVariadicCallee(CalleePtr);
+
+  if (llvm::Function *OrigFn = simplifyVariadicCallee(IRFuncTy, CalleePtr)) {
+    CalleePtr = OrigFn;
+    IRFuncTy = OrigFn->getFunctionType();
+  }
 
   // 3. Perform the actual call.
 
   // Deactivate any cleanups that we're supposed to do immediately before
   // the call.
   if (!CallArgs.getCleanupsToDeactivate().empty())
     deactivateArgCleanupsBeforeCall(*this, CallArgs);
 
#endif
   llvm::BasicBlock *InvokeDest = CannotThrow ? nullptr : getInvokeDest();
 
   SmallVector<llvm::OperandBundleDef, 1> BundleList =
       getBundlesForFunclet(CalleePtr);
 
   // Emit the actual call/invoke instruction.
   llvm::CallBase *CI;
   if (!InvokeDest) {
-    CI = Builder.CreateCall(CalleePtr, IRCallArgs, BundleList);
+    CI = Builder.CreateCall(IRFuncTy, CalleePtr, IRCallArgs, BundleList);
   } else {
     llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
-    CI = Builder.CreateInvoke(CalleePtr, Cont, InvokeDest, IRCallArgs,
+    CI = Builder.CreateInvoke(IRFuncTy, CalleePtr, Cont, InvokeDest, IRCallArgs,
                               BundleList);
     EmitBlock(Cont);
   }
   if (callOrInvoke)
     *callOrInvoke = CI;
 
   // Apply the attributes and calling convention.
   CI->setAttributes(Attrs);
#endif
 
   return Ret;
 }
 
 CGCallee CGCallee::prepareConcreteCallee(CodeGenFunction &CGF) const {
   if (isVirtual()) {
     const CallExpr *CE = getVirtualCallExpr();
     return CGF.CGM.getCXXABI().getVirtualFunctionPointer(
-        CGF, getVirtualMethodDecl(), getThisAddress(), getFunctionType(),
+        CGF, getVirtualMethodDecl(), getThisAddress(), getVirtualFunctionType(),
         CE ? CE->getBeginLoc() : SourceLocation());
   }
 
   return *this;
 }
 
 /* VarArg handling */