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.

4 files changed, 105 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);
 
diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 1bbd92c..228515a 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -7726,6 +7726,54 @@ riscv_emit_attribute ()
            riscv_stack_boundary / 8);
 }
 
+/* Output .variant_cc for function symbol which follows vector calling
+   convention.  */
+
+static void
+riscv_asm_output_variant_cc (FILE *stream, const tree decl, const char *name)
+{
+  if (TREE_CODE (decl) == FUNCTION_DECL)
+    {
+      riscv_cc cc = (riscv_cc) fndecl_abi (decl).id ();
+      if (cc == RISCV_CC_V)
+	{
+	  fprintf (stream, "\t.variant_cc\t");
+	  assemble_name (stream, name);
+	  fprintf (stream, "\n");
+	}
+    }
+}
+
+/* Implement ASM_DECLARE_FUNCTION_NAME.  */
+
+void
+riscv_declare_function_name (FILE *stream, const char *name, tree fndecl)
+{
+  riscv_asm_output_variant_cc (stream, fndecl, name);
+  ASM_OUTPUT_TYPE_DIRECTIVE (stream, name, "function");
+  ASM_OUTPUT_LABEL (stream, name);
+}
+
+/* Implement ASM_OUTPUT_DEF_FROM_DECLS.  */
+
+void
+riscv_asm_output_alias (FILE *stream, const tree decl, const tree target)
+{
+  const char *name = XSTR (XEXP (DECL_RTL (decl), 0), 0);
+  const char *value = IDENTIFIER_POINTER (target);
+  riscv_asm_output_variant_cc (stream, decl, name);
+  ASM_OUTPUT_DEF (stream, name, value);
+}
+
+/* Implement ASM_OUTPUT_EXTERNAL.  */
+
+void
+riscv_asm_output_external (FILE *stream, tree decl, const char *name)
+{
+  default_elf_asm_output_external (stream, decl, name);
+  riscv_asm_output_variant_cc (stream, decl, name);
+}
+
 /* Implement TARGET_ASM_FILE_START.  */
 
 static void
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index 68be4f3..7ac7884 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -1049,6 +1049,21 @@ while (0)
 
 #define ASM_COMMENT_START "#"
 
+/* Add output .variant_cc directive for specific function definition.  */
+#undef ASM_DECLARE_FUNCTION_NAME
+#define ASM_DECLARE_FUNCTION_NAME(STR, NAME, DECL)                             \
+  riscv_declare_function_name (STR, NAME, DECL)
+
+/* Add output .variant_cc directive for specific alias definition.  */
+#undef ASM_OUTPUT_DEF_FROM_DECLS
+#define ASM_OUTPUT_DEF_FROM_DECLS(STR, DECL, TARGET)                           \
+  riscv_asm_output_alias (STR, DECL, TARGET)
+
+/* Add output .variant_cc directive for specific extern function.  */
+#undef ASM_OUTPUT_EXTERNAL
+#define ASM_OUTPUT_EXTERNAL(STR, DECL, NAME)                                   \
+  riscv_asm_output_external (STR, DECL, NAME)
+
 #undef SIZE_TYPE
 #define SIZE_TYPE (POINTER_SIZE == 64 ? "long unsigned int" : "unsigned int")
 
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-variant_cc.c b/gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-variant_cc.c
new file mode 100644
index 0000000..6459f8e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/abi-call-variant_cc.c
@@ -0,0 +1,39 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv64gcv -mabi=lp64d -O1 --param=riscv-vector-abi -Wno-psabi" } */
+
+#include "riscv_vector.h"
+
+void
+f_undef1 (vint8m1_t a);
+void
+f_undef2 (vint8m1x8_t a);
+void
+f_undef3 (vbool1_t a);
+vint8m1_t
+f_undef4 ();
+
+void
+bar_real (vint8m1_t a, vint8m1x8_t b, vbool1_t c)
+{
+  f_undef1 (a);
+  f_undef2 (b);
+  f_undef3 (c);
+}
+
+__attribute__ ((alias ("bar_real"))) void
+bar_alias (vint8m1_t a, vint8m1x8_t b, vbool1_t c);
+
+void
+f_1 (vint8m1_t *a, vint8m1x8_t *b, vbool1_t *c)
+{
+  bar_alias (*a, *b, *c);
+  *a = f_undef4 ();
+}
+
+/* { dg-final { scan-assembler-times {\.variant_cc\tbar_real} 1 } } */
+/* { dg-final { scan-assembler-times {\.variant_cc\tbar_alias} 1 } } */
+/* { dg-final { scan-assembler-times {\.variant_cc\tf_1} 0 } } */
+/* { dg-final { scan-assembler-times {\.variant_cc\tf_undef1} 1 } } */
+/* { dg-final { scan-assembler-times {\.variant_cc\tf_undef2} 1 } } */
+/* { dg-final { scan-assembler-times {\.variant_cc\tf_undef3} 1 } } */
+/* { dg-final { scan-assembler-times {\.variant_cc\tf_undef4} 1 } } */