Fix function call handling according to Microsoft Arm64 variadic function call ABI

Author: Blackhex

gcc/config.gcc

@@ -346,7 +346,10 @@ m32c*-*-*)
         ;;
 aarch64*-*-*)
 	cpu_type=aarch64
-	extra_headers="arm_fp16.h arm_neon.h arm_bf16.h arm_acle.h arm_sve.h arm_sme.h arm_neon_sve_bridge.h arm_private_fp8.h arm_private_neon_types.h"
+	extra_headers="arm_fp16.h arm_neon.h arm_bf16.h arm_acle.h arm_sve.h
+		       arm_sme.h arm_neon_sve_bridge.h arm_private_fp8.h
+		       arm_private_neon_types.h
+		       cross-stdarg.h"
 	c_target_objs="aarch64-c.o"
 	cxx_target_objs="aarch64-c.o"
 	d_target_objs="aarch64-d.o"

gcc/config/aarch64/aarch64-builtins.cc

@@ -2485,6 +2485,36 @@ aarch64_general_init_builtins (void)
     handle_arm_acle_h ();
 }
 
+/* Internal method for aarch64_ms_variadic_abi_init_builtins.  */
+
+void
+aarch64_ms_variadic_abi_init_builtins (void)
+{
+  tree ms_va_ref;
+  tree fnvoid_va_end_ms;
+  tree fnvoid_va_start_ms;
+  tree fnvoid_va_copy_ms;
+  tree fnattr_ms = NULL_TREE;
+
+  fnattr_ms = build_tree_list (get_identifier ("ms_abi"), NULL_TREE);
+  ms_va_ref = build_reference_type (ms_va_list_type_node);
+
+  fnvoid_va_end_ms = build_function_type_list (void_type_node, ms_va_ref,
+					       NULL_TREE);
+  fnvoid_va_start_ms
+    = build_varargs_function_type_list (void_type_node, ms_va_ref, NULL_TREE);
+  fnvoid_va_copy_ms
+    = build_function_type_list (void_type_node, ms_va_ref, ms_va_list_type_node,
+				NULL_TREE);
+
+  add_builtin_function ("__builtin_ms_va_start", fnvoid_va_start_ms,
+  			BUILT_IN_VA_START, BUILT_IN_NORMAL, NULL, fnattr_ms);
+  add_builtin_function ("__builtin_ms_va_end", fnvoid_va_end_ms,
+  			BUILT_IN_VA_END, BUILT_IN_NORMAL, NULL, fnattr_ms);
+  add_builtin_function ("__builtin_ms_va_copy", fnvoid_va_copy_ms,
+			BUILT_IN_VA_COPY, BUILT_IN_NORMAL, NULL, fnattr_ms);
+}
+
 /* Implement TARGET_BUILTIN_DECL for the AARCH64_BUILTIN_GENERAL group.  */
 tree
 aarch64_general_builtin_decl (unsigned code, bool)

gcc/config/aarch64/aarch64-protos.h

@@ -1109,6 +1109,8 @@ void aarch64_override_options_internal (struct gcc_options *);
 
 const char *aarch64_general_mangle_builtin_type (const_tree);
 void aarch64_general_init_builtins (void);
+void aarch64_ms_variadic_abi_init_builtins (void);
+
 tree aarch64_general_fold_builtin (unsigned int, tree, unsigned int, tree *);
 gimple *aarch64_general_gimple_fold_builtin (unsigned int, gcall *,
 					     gimple_stmt_iterator *);