aarch64: Add aarch64-w64-mingw32 COFF

Define ASM specific for COFF format on AArch64.

gcc/ChangeLog:

	* config.gcc: Add COFF format support definitions.
	* config/aarch64/aarch64-coff.h: New file.

gcc/config.gcc

@@ -1272,6 +1272,7 @@ aarch64*-*-gnu*)
 	;;
 aarch64-*-mingw*)
 	tm_file="${tm_file} aarch64/aarch64-abi-ms.h"
+	tm_file="${tm_file} aarch64/aarch64-coff.h"
 	tmake_file="${tmake_file} aarch64/t-aarch64"
 	case ${enable_threads} in
 	  "" | yes | win32)

gcc/config/aarch64/aarch64-coff.h

@@ -0,0 +1,91 @@
+/* Machine description for AArch64 architecture.
+   Copyright (C) 2024 Free Software Foundation, Inc.
+
+   This file is part of GCC.
+
+   GCC is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   GCC is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GCC; see the file COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef GCC_AARCH64_COFF_H
+#define GCC_AARCH64_COFF_H
+
+#ifndef LOCAL_LABEL_PREFIX
+# define LOCAL_LABEL_PREFIX 	""
+#endif
+
+/* Using long long breaks -ansi and -std=c90, so these will need to be
+   made conditional for an LLP64 ABI.  */
+#undef SIZE_TYPE
+#define SIZE_TYPE	"long long unsigned int"
+
+#undef PTRDIFF_TYPE
+#define PTRDIFF_TYPE	"long long int"
+
+#undef LONG_TYPE_SIZE
+#define LONG_TYPE_SIZE 32
+
+#ifndef ASM_GENERATE_INTERNAL_LABEL
+# define ASM_GENERATE_INTERNAL_LABEL(STRING, PREFIX, NUM)  \
+  sprintf (STRING, "*%s%s%u", LOCAL_LABEL_PREFIX, PREFIX, (unsigned int)(NUM))
+#endif
+
+#define ASM_OUTPUT_ALIGN(STREAM, POWER)		\
+  fprintf (STREAM, "\t.align\t%d\n", (int)POWER)
+
+/* Output a common block.  */
+#ifndef ASM_OUTPUT_COMMON
+# define ASM_OUTPUT_COMMON(STREAM, NAME, SIZE, ROUNDED)	\
+    {							\
+      fprintf (STREAM, "\t.comm\t");			\
+      assemble_name (STREAM, NAME);			\
+      asm_fprintf (STREAM, ", %d, %d\n", 		\
+      (int)(ROUNDED), (int)(SIZE));	\
+    }
+#endif
+
+/* Output a local common block.  /bin/as can't do this, so hack a
+   `.space' into the bss segment.  Note that this is *bad* practice,
+   which is guaranteed NOT to work since it doesn't define STATIC
+   COMMON space but merely STATIC BSS space.  */
+#ifndef ASM_OUTPUT_ALIGNED_LOCAL
+# define ASM_OUTPUT_ALIGNED_LOCAL(STREAM, NAME, SIZE, ALIGN)		\
+    {									\
+      switch_to_section (bss_section);					\
+      ASM_OUTPUT_ALIGN (STREAM, floor_log2 (ALIGN / BITS_PER_UNIT));	\
+      ASM_OUTPUT_LABEL (STREAM, NAME);					\
+      fprintf (STREAM, "\t.space\t%d\n", (int)(SIZE));			\
+    }
+#endif
+
+#define ASM_OUTPUT_SKIP(STREAM, NBYTES) 	\
+  fprintf (STREAM, "\t.space\t%d  // skip\n", (int) (NBYTES))
+
+/* Definitions that are not yet supported by binutils for the
+   aarch64-w64-mingw32 target.  */
+#define ASM_OUTPUT_TYPE_DIRECTIVE(STREAM, NAME, TYPE)
+#define ASM_DECLARE_FUNCTION_SIZE(FILE, FNAME, DECL)
+
+#define TEXT_SECTION_ASM_OP	"\t.text"
+#define DATA_SECTION_ASM_OP	"\t.data"
+#define BSS_SECTION_ASM_OP	"\t.bss"
+
+#define CTORS_SECTION_ASM_OP	"\t.section\t.ctors, \"aw\""
+#define DTORS_SECTION_ASM_OP	"\t.section\t.dtors, \"aw\""
+
+#define GLOBAL_ASM_OP "\t.global\t"
+
+#undef SUPPORTS_INIT_PRIORITY
+#define SUPPORTS_INIT_PRIORITY 0
+
+#endif