Select functions through their names insead of only ABI

Author: sayantn

compiler/rustc_codegen_gcc/src/type_of.rs

@@ -373,7 +373,11 @@ impl<'gcc, 'tcx> LayoutTypeCodegenMethods<'tcx> for CodegenCx<'gcc, 'tcx> {
         unimplemented!();
     }
 
-    fn fn_decl_backend_type(&self, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> Type<'gcc> {
+    fn fn_decl_backend_type(
+        &self,
+        fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
+        _fn_ptr: RValue<'gcc>,
+    ) -> Type<'gcc> {
         // FIXME(antoyo): Should we do something with `FnAbiGcc::fn_attributes`?
         let FnAbiGcc { return_type, arguments_type, is_c_variadic, .. } = fn_abi.gcc_type(self);
         self.context.new_function_pointer_type(None, return_type, &arguments_type, is_c_variadic)

compiler/rustc_codegen_llvm/src/abi.rs

@@ -309,7 +309,7 @@ impl<'ll, 'tcx> ArgAbiBuilderMethods<'tcx> for Builder<'_, 'll, 'tcx> {
 }
 
 pub(crate) trait FnAbiLlvmExt<'ll, 'tcx> {
-    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
+    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>, name: &[u8]) -> &'ll Type;
     fn ptr_to_llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type;
     fn llvm_cconv(&self, cx: &CodegenCx<'ll, 'tcx>) -> llvm::CallConv;
 
@@ -326,20 +326,22 @@ pub(crate) trait FnAbiLlvmExt<'ll, 'tcx> {
 }
 
 impl<'ll, 'tcx> FnAbiLlvmExt<'ll, 'tcx> for FnAbi<'tcx, Ty<'tcx>> {
-    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>) -> &'ll Type {
+    fn llvm_type(&self, cx: &CodegenCx<'ll, 'tcx>, name: &[u8]) -> &'ll Type {
         // Ignore "extra" args from the call site for C variadic functions.
         // Only the "fixed" args are part of the LLVM function signature.
         let args =
             if self.c_variadic { &self.args[..self.fixed_count as usize] } else { &self.args };
 
+        // todo(sayantn): a better way is to look at the `link_name` instead of the function name, because function name can be "faked" using `#[export_name]`
+        let llvm_intrinsic = name.starts_with(b"llvm.")
+            && !self.c_variadic
+            && self.conv == Conv::C
+            && !self.can_unwind;
+        let amx_intrinsic =
+            llvm_intrinsic && name.starts_with(b"llvm.x86.") && name.ends_with(b".internal");
         let adjust_ty = |ty| {
-            // todo: rectify this to be more selective (help wanted)
-            let probably_unadjusted = self.conv == Conv::C && !self.can_unwind && !self.c_variadic;
-            let probably_amx_intrinsic = probably_unadjusted && cx.tcx.sess.target.arch == "x86_64";
             // Change type to `x86amx` from `i32x256` for x86_64 AMX intrinsics
-            if probably_amx_intrinsic
-                && cx.type_kind(ty) == TypeKind::Vector
-                && cx.vector_length(ty) == 256
+            if amx_intrinsic && cx.type_kind(ty) == TypeKind::Vector && cx.vector_length(ty) == 256
             {
                 let element_ty = cx.element_type(ty);
                 if cx.type_kind(element_ty) == TypeKind::Integer && cx.int_width(element_ty) == 32 {

compiler/rustc_codegen_llvm/src/declare.rs

@@ -158,7 +158,7 @@ impl<'ll, 'tcx> CodegenCx<'ll, 'tcx> {
             fn_abi.llvm_cconv(self),
             llvm::UnnamedAddr::Global,
             llvm::Visibility::Default,
-            fn_abi.llvm_type(self),
+            fn_abi.llvm_type(self, name.as_ref()),
         );
         fn_abi.apply_attrs_llfn(self, llfn, instance);
 

compiler/rustc_codegen_llvm/src/intrinsic.rs

@@ -1090,7 +1090,7 @@ fn gen_fn<'a, 'll, 'tcx>(
     codegen: &mut dyn FnMut(Builder<'a, 'll, 'tcx>),
 ) -> (&'ll Type, &'ll Value) {
     let fn_abi = cx.fn_abi_of_fn_ptr(rust_fn_sig, ty::List::empty());
-    let llty = fn_abi.llvm_type(cx);
+    let llty = fn_abi.llvm_type(cx, name.as_ref());
     let llfn = cx.declare_fn(name, fn_abi, None);
     cx.set_frame_pointer_type(llfn);
     cx.apply_target_cpu_attr(llfn);

compiler/rustc_codegen_llvm/src/type_.rs

@@ -288,8 +288,12 @@ impl<'ll, 'tcx> LayoutTypeCodegenMethods<'tcx> for CodegenCx<'ll, 'tcx> {
     fn cast_backend_type(&self, ty: &CastTarget) -> &'ll Type {
         ty.llvm_type(self)
     }
-    fn fn_decl_backend_type(&self, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> &'ll Type {
-        fn_abi.llvm_type(self)
+    fn fn_decl_backend_type(
+        &self,
+        fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
+        fn_ptr: &'ll Value,
+    ) -> &'ll Type {
+        fn_abi.llvm_type(self, llvm::get_value_name(fn_ptr))
     }
     fn fn_ptr_backend_type(&self, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> &'ll Type {
         fn_abi.ptr_to_llvm_type(self)

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -187,7 +187,7 @@ impl<'a, 'tcx> TerminatorCodegenHelper<'tcx> {
 
         // If there is a cleanup block and the function we're calling can unwind, then
         // do an invoke, otherwise do a call.
-        let fn_ty = bx.fn_decl_backend_type(fn_abi);
+        let fn_ty = bx.fn_decl_backend_type(fn_abi, fn_ptr);
 
         let fn_attrs = if bx.tcx().def_kind(fx.instance.def_id()).has_codegen_attrs() {
             Some(bx.tcx().codegen_fn_attrs(fx.instance.def_id()))
@@ -1806,7 +1806,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         if is_call_from_compiler_builtins_to_upstream_monomorphization(bx.tcx(), instance) {
             bx.abort();
         } else {
-            let fn_ty = bx.fn_decl_backend_type(fn_abi);
+            let fn_ty = bx.fn_decl_backend_type(fn_abi, fn_ptr);
 
             let llret = bx.call(fn_ty, None, Some(fn_abi), fn_ptr, &[], funclet.as_ref(), None);
             bx.apply_attrs_to_cleanup_callsite(llret);

compiler/rustc_codegen_ssa/src/mir/rvalue.rs

@@ -779,7 +779,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     };
                     let fn_ptr = bx.get_fn_addr(instance);
                     let fn_abi = bx.fn_abi_of_instance(instance, ty::List::empty());
-                    let fn_ty = bx.fn_decl_backend_type(fn_abi);
+                    let fn_ty = bx.fn_decl_backend_type(fn_abi, fn_ptr);
                     let fn_attrs = if bx.tcx().def_kind(instance.def_id()).has_codegen_attrs() {
                         Some(bx.tcx().codegen_fn_attrs(instance.def_id()))
                     } else {

compiler/rustc_codegen_ssa/src/size_of_val.rs

@@ -67,7 +67,7 @@ pub fn size_and_align_of_dst<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
             // Generate the call. Cannot use `do_call` since we don't have a MIR terminator so we
             // can't create a `TerminationCodegenHelper`. (But we are in good company, this code is
             // duplicated plenty of times.)
-            let fn_ty = bx.fn_decl_backend_type(fn_abi);
+            let fn_ty = bx.fn_decl_backend_type(fn_abi, llfn);
 
             bx.call(
                 fn_ty,

compiler/rustc_codegen_ssa/src/traits/type_.rs

@@ -96,7 +96,11 @@ pub trait LayoutTypeCodegenMethods<'tcx>: BackendTypes {
     /// such as when it's stack-allocated or when it's being loaded or stored.
     fn backend_type(&self, layout: TyAndLayout<'tcx>) -> Self::Type;
     fn cast_backend_type(&self, ty: &CastTarget) -> Self::Type;
-    fn fn_decl_backend_type(&self, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> Self::Type;
+    fn fn_decl_backend_type(
+        &self,
+        fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
+        fn_ptr: Self::Value,
+    ) -> Self::Type;
     fn fn_ptr_backend_type(&self, fn_abi: &FnAbi<'tcx, Ty<'tcx>>) -> Self::Type;
     fn reg_backend_type(&self, ty: &Reg) -> Self::Type;
     /// The backend type used for a rust type when it's in an SSA register.