[PATCH 2/3] RISC-V: Stricter underscore handling for ISA

[Tsukasa OI <research_trasio@irq.a4lg.com>]

Double underscores and trailing underscore in an ISA string are invalid.

bfd/ChangeLog:

	* elfxx-riscv.c (riscv_parse_std_ext): Make handling for
	underscores in ISA string more strict.
	(riscv_parse_prefixed_ext): Likewise.
---
 bfd/elfxx-riscv.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index 329dcaed304..ee4b442ba89 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1650,6 +1650,8 @@ riscv_parse_std_ext (riscv_parse_subset_t *rps,
 		     const char *arch,
 		     const char *p)
 {
+  unsigned char underscores = 0;
+
   /* First letter must start with i, e or g.  */
   if (*p != 'e' && *p != 'i' && *p != 'g')
     {
@@ -1669,8 +1671,15 @@ riscv_parse_std_ext (riscv_parse_subset_t *rps,
       if (*p == '_')
 	{
 	  p++;
+	  if (++underscores == 2)
+	    {
+	      rps->error_handler
+		(_("%s: double underscores"), arch);
+	      return NULL;
+	    }
 	  continue;
 	}
+      underscores = 0;
 
       bool implicit = false;
       int major = RISCV_UNKNOWN_VERSION;
@@ -1709,7 +1718,7 @@ riscv_parse_std_ext (riscv_parse_subset_t *rps,
       riscv_parse_add_subset (rps, subset, major, minor, implicit);
     }
 
-  return p;
+  return p - underscores;
 }
 
 /* Parsing function for prefixed extensions.
@@ -1731,14 +1740,22 @@ riscv_parse_prefixed_ext (riscv_parse_subset_t *rps,
   int minor_version;
   const char *last_name;
   enum riscv_prefix_ext_class class;
+  unsigned char underscores = 0;
 
   while (*p)
     {
       if (*p == '_')
 	{
 	  p++;
+	  if (++underscores == 2)
+	    {
+	      rps->error_handler
+		(_("%s: double underscores"), arch);
+	      return NULL;
+	    }
 	  continue;
 	}
+      underscores = 0;
 
       class = riscv_get_prefix_class (p);
       if (class == RV_ISA_CLASS_UNKNOWN)
@@ -1843,6 +1860,12 @@ riscv_parse_prefixed_ext (riscv_parse_subset_t *rps,
 	}
     }
 
+  if (underscores)
+    {
+      rps->error_handler
+	(_("%s: trailing underscore"), arch);
+      return NULL;
+    }
   return p;
 }
 
-- 
2.32.0