RISC-V: PR32014, .option directives shuoldn't affect elf attribute.

The .option arch/rvc/norvc/push/pop directives can only take effect for a
small/large specific code region, so they are not file-level architecture
setting.  They should only affect the mapping symbols only rather than the
file-level elf architecture attribute.  Otherwise, the elf architecture
attribute will appear to missing some extensions when -flto merges files
with different .option architecture settings.

gas/
	PR 32014
	* config/tc-riscv.c (file_arch_str): New const char *, rather than the
	arch_str in the riscv_rps_as.subset_list, it's file-level so only be
	affected by .attribute arch directive.
	(riscv_reset_subsets_list_arch_str): Renamed to riscv_set_arch_str, and
	also can handle both file_arch_str and arch_str in subset_list, just
	give the pointer address as the input.
	(riscv_set_arch): Called by -march and .attribute arch, so set both
	file_arch_str and arch_str in subset_list.
	(s_riscv_option): Updated .option arch/rvc/norvc/push/pop that only
	set the arch_str in subset_list.
	(riscv_write_out_attrs): Output elf architecture attribute according to
	file_arch_str.  Freed file_arch_str.
	* doc/c-riscv.texi: Added destrbution that .option directives shouldn't
	affect the elf attribute settings.
	* testsuite/gas/riscv/option-arch.s: From option-arch-01/02/03 merged.
	* testsuite/gas/riscv/option-arch-dis.d: Likewise, for dis-assembler.
	* testsuite/gas/riscv/option-arch-attr.d: Likewise, to check readelf -A.

1 files changed, 16 insertions, 12 deletions

diff --git a/gas/config/tc-riscv.c b/gas/config/tc-riscv.c
index 779e0b8..15244be 100644
--- a/gas/config/tc-riscv.c
+++ b/gas/config/tc-riscv.c
@@ -162,6 +162,7 @@ struct riscv_ip_error
 
 static const char default_arch[] = DEFAULT_ARCH;
 static const char *default_arch_with_ext = DEFAULT_RISCV_ARCH_WITH_EXT;
+static const char *file_arch_str = NULL;
 static enum riscv_spec_class default_isa_spec = ISA_SPEC_CLASS_NONE;
 static enum riscv_spec_class default_priv_spec = PRIV_SPEC_CLASS_NONE;
 
@@ -305,15 +306,17 @@ static riscv_parse_subset_t riscv_rps_as =
   true,			/* check_unknown_prefixed_ext.  */
 };
 
-/* Update the architecture string in the subset_list.  */
+/* Update file/function-level architecture string according to the
+   subset_list.  */
 
 static void
-riscv_reset_subsets_list_arch_str (void)
+riscv_set_arch_str (const char **arch_str_p)
 {
   riscv_subset_list_t *subsets = riscv_rps_as.subset_list;
-  if (subsets->arch_str != NULL)
-    free ((void *) subsets->arch_str);
-  subsets->arch_str = riscv_arch_str (xlen, subsets);
+  const char *arch_str = *arch_str_p;
+  if (arch_str != NULL)
+    free ((void *) arch_str);
+  *arch_str_p = riscv_arch_str (xlen, subsets);
 }
 
 /* This structure is used to hold a stack of .option values.  */
@@ -347,7 +350,8 @@ riscv_set_arch (const char *s)
     }
   riscv_release_subset_list (riscv_rps_as.subset_list);
   riscv_parse_subset (&riscv_rps_as, s);
-  riscv_reset_subsets_list_arch_str ();
+  riscv_set_arch_str (&file_arch_str);
+  riscv_set_arch_str (&riscv_rps_as.subset_list->arch_str);
 
   riscv_set_rvc (false);
   if (riscv_subset_supports (&riscv_rps_as, "c")
@@ -4837,13 +4841,13 @@ s_riscv_option (int x ATTRIBUTE_UNUSED)
   if (strcmp (name, "rvc") == 0)
     {
       riscv_update_subset (&riscv_rps_as, "+c");
-      riscv_reset_subsets_list_arch_str ();
+      riscv_set_arch_str (&riscv_rps_as.subset_list->arch_str);
       riscv_set_rvc (true);
     }
   else if (strcmp (name, "norvc") == 0)
     {
       riscv_update_subset (&riscv_rps_as, "-c");
-      riscv_reset_subsets_list_arch_str ();
+      riscv_set_arch_str (&riscv_rps_as.subset_list->arch_str);
       riscv_set_rvc (false);
     }
   else if (strcmp (name, "pic") == 0)
@@ -4864,7 +4868,7 @@ s_riscv_option (int x ATTRIBUTE_UNUSED)
       if (ISSPACE (*name) && *name != '\0')
 	name++;
       riscv_update_subset (&riscv_rps_as, name);
-      riscv_reset_subsets_list_arch_str ();
+      riscv_set_arch_str (&riscv_rps_as.subset_list->arch_str);
 
       riscv_set_rvc (false);
       if (riscv_subset_supports (&riscv_rps_as, "c")
@@ -5389,7 +5393,7 @@ s_riscv_insn (int x ATTRIBUTE_UNUSED)
 static void
 riscv_write_out_attrs (void)
 {
-  const char *arch_str, *priv_str, *p;
+  const char *priv_str, *p;
   /* versions[0]: major version.
      versions[1]: minor version.
      versions[2]: revision version.  */
@@ -5397,10 +5401,10 @@ riscv_write_out_attrs (void)
   unsigned int i;
 
   /* Re-write architecture elf attribute.  */
-  arch_str = riscv_rps_as.subset_list->arch_str;
-  if (!bfd_elf_add_proc_attr_string (stdoutput, Tag_RISCV_arch, arch_str))
+  if (!bfd_elf_add_proc_attr_string (stdoutput, Tag_RISCV_arch, file_arch_str))
     as_fatal (_("error adding attribute: %s"),
 	      bfd_errmsg (bfd_get_error ()));
+  free ((void *) file_arch_str);
 
   /* For the file without any instruction, we don't set the default_priv_spec
      according to the privileged elf attributes since the md_assemble isn't