RISC-V: Part-3: Output .variant_cc directive for vector function

Functions which follow vector calling convention variant need be annotated by
.variant_cc directive according the RISC-V Assembly Programmer's Manual[1] and
RISC-V ELF Specification[2].

[1] https://github.com/riscv-non-isa/riscv-asm-manual/blob/master/riscv-asm.md#pseudo-ops
[2] https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-elf.adoc#dynamic-linking

gcc/ChangeLog:

	* config/riscv/riscv-protos.h (riscv_declare_function_name): Add protos.
	(riscv_asm_output_alias): Ditto.
	(riscv_asm_output_external): Ditto.
	* config/riscv/riscv.cc (riscv_asm_output_variant_cc):
	Output .variant_cc directive for vector function.
	(riscv_declare_function_name): Ditto.
	(riscv_asm_output_alias): Ditto.
	(riscv_asm_output_external): Ditto.
	* config/riscv/riscv.h (ASM_DECLARE_FUNCTION_NAME):
	Implement ASM_DECLARE_FUNCTION_NAME.
	(ASM_OUTPUT_DEF_FROM_DECLS): Implement ASM_OUTPUT_DEF_FROM_DECLS.
	(ASM_OUTPUT_EXTERNAL): Implement ASM_OUTPUT_EXTERNAL.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/base/abi-call-variant_cc.c: New test.

1 files changed, 3 insertions, 0 deletions

diff --git a/gcc/config/riscv/riscv-protos.h b/gcc/config/riscv/riscv-protos.h
index 7c2bbd9..6dbf6b9 100644
--- a/gcc/config/riscv/riscv-protos.h
+++ b/gcc/config/riscv/riscv-protos.h
@@ -102,6 +102,9 @@ extern bool riscv_split_64bit_move_p (rtx, rtx);
 extern void riscv_split_doubleword_move (rtx, rtx);
 extern const char *riscv_output_move (rtx, rtx);
 extern const char *riscv_output_return ();
+extern void riscv_declare_function_name (FILE *, const char *, tree);
+extern void riscv_asm_output_alias (FILE *, const tree, const tree);
+extern void riscv_asm_output_external (FILE *, const tree, const char *);
 extern bool
 riscv_zcmp_valid_stack_adj_bytes_p (HOST_WIDE_INT, int);