remove duplicated LLVM wrapper function

Author: ZuseZ4

compiler/rustc_codegen_llvm/src/builder.rs

@@ -123,7 +123,7 @@ pub(crate) fn generate_enzyme_call<'ll>(
         // arguments. We do however need to declare them with their correct return type.
         // We already figured the correct return type out in our frontend, when generating the outer_fn,
         // so we can now just go ahead and use that. FIXME(ZuseZ4): This doesn't handle sret yet.
-        let fn_ty = llvm::LLVMRustGetFunctionType(outer_fn);
+        let fn_ty = llvm::LLVMGlobalGetValueType(outer_fn);
         let ret_ty = llvm::LLVMGetReturnType(fn_ty);
 
         // LLVM can figure out the input types on it's own, so we take a shortcut here.

compiler/rustc_codegen_llvm/src/llvm/enzyme_ffi.rs

@@ -11,7 +11,6 @@ extern "C" {
     pub fn LLVMRustDIGetInstMetadata(I: &Value) -> &Metadata;
     pub fn LLVMRustEraseInstFromParent(V: &Value);
     pub fn LLVMRustGetTerminator<'a>(B: &BasicBlock) -> &'a Value;
-    pub fn LLVMRustGetFunctionType(fnc: &Value) -> &Type;
 
     pub fn LLVMGetReturnType(T: &Type) -> &Type;
     pub fn LLVMDumpModule(M: &Module);

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -399,11 +399,6 @@ extern "C" void LLVMRustEraseInstFromParent(LLVMValueRef Instr) {
   }
 }
 
-extern "C" LLVMTypeRef LLVMRustGetFunctionType(LLVMValueRef Fn) {
-  auto Ftype = unwrap<Function>(Fn)->getFunctionType();
-  return wrap(Ftype);
-}
-
 extern "C" LLVMAttributeRef
 LLVMRustCreateAttrNoValue(LLVMContextRef C, LLVMRustAttributeKind RustAttr) {
   return wrap(Attribute::get(*unwrap(C), fromRust(RustAttr)));