implement codegen for functions whose function body type don't match
their prototype.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@44506 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CodeGen/CodeGenFunction.cpp b/CodeGen/CodeGenFunction.cpp
index 0da5fcd..190da77 100644
--- a/CodeGen/CodeGenFunction.cpp
+++ b/CodeGen/CodeGenFunction.cpp
@@ -58,8 +58,42 @@
getContext().getTypeSize(getContext().getPointerType(getContext().VoidTy),
SourceLocation()));
- CurFn = cast<llvm::Function>(CGM.GetAddrOfGlobalDecl(FD));
CurFuncDecl = FD;
+ llvm::Constant *CurFnC = CGM.GetAddrOfGlobalDecl(FD);
+ if (!(CurFn = dyn_cast<llvm::Function>(CurFnC))) {
+ // If CurFnC is not a constant, it must be a bitcast of another function.
+ llvm::ConstantExpr *CurFnCE = cast<llvm::ConstantExpr>(CurFnC);
+ assert(CurFnCE->getOpcode() == llvm::Instruction::BitCast &&
+ "Unexpected name collision");
+ llvm::Function *OtherFunc = cast<llvm::Function>(CurFnCE->getOperand(0));
+
+ // This happens if there is a prototype for a function (e.g. "int f()") and
+ // then a definition of a different type (e.g. "int f(int x)"). Start by
+ // making a new function of the correct type, RAUW, then steal the name.
+ const llvm::PointerType *PTy = cast<llvm::PointerType>(CurFnC->getType());
+ const llvm::FunctionType *FTy =
+ cast<llvm::FunctionType>(PTy->getElementType());
+ CurFn = new llvm::Function(FTy, llvm::Function::ExternalLinkage, "",
+ &CGM.getModule());
+ CurFn->takeName(OtherFunc);
+
+ // Replace uses of OtherFunc with the Function we will endow with a body.
+ llvm::Constant *NewPtrForOldDecl =
+ llvm::ConstantExpr::getBitCast(CurFn, OtherFunc->getType());
+ OtherFunc->replaceAllUsesWith(NewPtrForOldDecl);
+
+ // Make sure the GlobalDecl map for FD is up-to-date.
+ CGM.ChangeGlobalDeclMap(FD, CurFn);
+
+ // FIXME: Update the globaldeclmap for the previous decl of this name. We
+ // really want a way to walk all of these, but we don't have it yet. This
+ // is incredibly slow!
+ CGM.ReplaceMapValuesWith(OtherFunc, NewPtrForOldDecl);
+
+ // Ok, delete the old function now, which is dead.
+ assert(OtherFunc->isDeclaration() && "Shouldn't replace non-declaration");
+ OtherFunc->eraseFromParent();
+ }
assert(CurFn->isDeclaration() && "Function already has body?");