[PATCH] RISC-V: Change -march parsing.

[Maxim Blinov <maxim dot blinov at embecosm dot com>]

Change -march parsing logic so we can pass "z" prefixed arguments. The
code is originally taken from the riscv-bitmanip branch.

bfd/ChangeLog:

	* bfd/elfnn-riscv.c (riscv_skip_prefix): New function to skip
	extension prefixes.
	(riscv_non_stop_ext_p): Unused function removed.
	(riscv_std_sv_ext_p): Same
	(riscv_non_std_sv_ext_p): Same
	(riscv_merge_arch_attr_info): Replace 3 calls to
	`riscv_merge_non_std_and_sv_ext' with single call to
	`riscv_merge_multi_letter_ext'

	* bfd/elfxx-riscv.c (riscv_parse_std_ext): Break if we
	encounter a 'z' prefix.
	(riscv_get_prefix_class): New function, return prefix class based
	on first few characters of input string.
	(riscv_parse_config): New structure to factor out minor differences
	in extension class parsing behaviour.
	(riscv_parse_sv_or_non_std_ext): Rename to...
	(riscv_parse_prefixed_ext), and parameterise with
	`riscv_parse_config`.
	(riscv_std_z_ext_strtab):
	(riscv_std_s_ext_strtab): String tables of known z/s extensions.
	(riscv_parse_subset): Delegate all non-single-letter parsing work
	to `riscv_parse_prefixed_ext'.

	* bfd/elfxx-riscv.h (riscv_isa_ext_class): New type.

gas/testsuite/ChangeLog:

	* march-ok-s.d, march-ok-sx.d, march-ok-s-with-version: sx is no
	longer valid and s exts must be known, so rename *ok* to *fail*.
	* march-fail-s.l, march-fail-sx.l, march-fail-sx-with-version.l:
	Expected error messages for above.
---
 bfd/elfnn-riscv.c                             | 139 ++++++------
 bfd/elfxx-riscv.c                             | 197 ++++++++++++++----
 bfd/elfxx-riscv.h                             |  20 ++
 .../gas/riscv/march-fail-s-with-version       |   2 +
 ...-version.d => march-fail-s-with-version.d} |   1 +
 .../gas/riscv/march-fail-s-with-version.l     |   2 +
 .../riscv/{march-ok-s.d => march-fail-s.d}    |   1 +
 gas/testsuite/gas/riscv/march-fail-s.l        |   2 +
 .../riscv/{march-ok-sx.d => march-fail-sx.d}  |   3 +-
 gas/testsuite/gas/riscv/march-fail-sx.l       |   2 +
 10 files changed, 264 insertions(+), 105 deletions(-)
 create mode 100644 gas/testsuite/gas/riscv/march-fail-s-with-version
 rename gas/testsuite/gas/riscv/{march-ok-s-with-version.d => march-fail-s-with-version.d} (68%)
 create mode 100644 gas/testsuite/gas/riscv/march-fail-s-with-version.l
 rename gas/testsuite/gas/riscv/{march-ok-s.d => march-fail-s.d} (75%)
 create mode 100644 gas/testsuite/gas/riscv/march-fail-s.l
 rename gas/testsuite/gas/riscv/{march-ok-sx.d => march-fail-sx.d} (56%)
 create mode 100644 gas/testsuite/gas/riscv/march-fail-sx.l

diff --git a/bfd/elfnn-riscv.c b/bfd/elfnn-riscv.c
index 997f786602..82249fc88a 100644
--- a/bfd/elfnn-riscv.c
+++ b/bfd/elfnn-riscv.c
@@ -2735,30 +2735,6 @@ riscv_std_ext_p (const char *name)
   return (strlen (name) == 1) && (name[0] != 'x') && (name[0] != 's');
 }
 
-/* Predicator for non-standard extension.  */
-
-static bfd_boolean
-riscv_non_std_ext_p (const char *name)
-{
-  return (strlen (name) >= 2) && (name[0] == 'x');
-}
-
-/* Predicator for standard supervisor extension.  */
-
-static bfd_boolean
-riscv_std_sv_ext_p (const char *name)
-{
-  return (strlen (name) >= 2) && (name[0] == 's') && (name[1] != 'x');
-}
-
-/* Predicator for non-standard supervisor extension.  */
-
-static bfd_boolean
-riscv_non_std_sv_ext_p (const char *name)
-{
-  return (strlen (name) >= 3) && (name[0] == 's') && (name[1] == 'x');
-}
-
 /* Error handler when version mis-match.  */
 
 static void
@@ -2884,53 +2860,95 @@ riscv_merge_std_ext (bfd *ibfd,
   return TRUE;
 }
 
-/* Merge non-standard and supervisor extensions.
-   Return Value:
-     Return FALSE if failed to merge.
+static const char *
+riscv_skip_prefix (const char *ext, riscv_isa_ext_class_t c)
+{
+  switch (c)
+    {
+    case RV_ISA_CLASS_X: return &ext[1];
+    case RV_ISA_CLASS_S: return &ext[1];
+    case RV_ISA_CLASS_Z: return &ext[1];
+    default: return ext;
+    }
+}
 
-   Arguments:
-     `bfd`: bfd handler.
-     `in_arch`: Raw arch string for input object.
-     `out_arch`: Raw arch string for output object.
-     `pin`: subset list for input object, and it'll skip all merged subset after
-            merge.
-     `pout`: Like `pin`, but for output object. */
+/* Compare prefixed extension names canonically.  */
+
+static int
+riscv_prefix_cmp (const char *a, const char *b)
+{
+  riscv_isa_ext_class_t ca = riscv_get_prefix_class (a);
+  riscv_isa_ext_class_t cb = riscv_get_prefix_class (b);
+
+  /* Extension name without prefix  */
+  const char *anp = riscv_skip_prefix (a, ca);
+  const char *bnp = riscv_skip_prefix (b, cb);
+
+  if (ca == cb)
+    return strcmp (anp, bnp);
+
+  return (int)ca - (int)cb;
+}
 
 static bfd_boolean
-riscv_merge_non_std_and_sv_ext (bfd *ibfd,
-				riscv_subset_t **pin,
-				riscv_subset_t **pout,
-				bfd_boolean (*predicate_func) (const char *))
+riscv_merge_multi_letter_ext (bfd *ibfd,
+			      riscv_subset_t **pin,
+			      riscv_subset_t **pout)
 {
   riscv_subset_t *in = *pin;
   riscv_subset_t *out = *pout;
+  riscv_subset_t *tail;
 
-  for (in = *pin; in != NULL && predicate_func (in->name); in = in->next)
-    riscv_add_subset (&merged_subsets, in->name, in->major_version,
-		      in->minor_version);
+  int cmp;
 
-  for (out = *pout; out != NULL && predicate_func (out->name); out = out->next)
+  while (in && out)
     {
-      riscv_subset_t *find_ext =
-	riscv_lookup_subset (&merged_subsets, out->name);
-      if (find_ext != NULL)
+      cmp = riscv_prefix_cmp (in->name, out->name);
+
+      if (cmp < 0)
+	{
+	  /* `in' comes before `out', append `in' and increment.  */
+	  riscv_add_subset (&merged_subsets, in->name, in->major_version,
+			    in->minor_version);
+	  in = in->next;
+	}
+      else if (cmp > 0)
+	{
+	  /* `out' comes before `in', append `out' and increment.  */
+	  riscv_add_subset (&merged_subsets, out->name, out->major_version,
+			    out->minor_version);
+	  out = out->next;
+	}
+      else
 	{
-	  /* Check version is same or not. */
-	  /* TODO: Allow different merge policy.  */
-	  if ((find_ext->major_version != out->major_version)
-	      || (find_ext->minor_version != out->minor_version))
+	  /* Both present, check version and increment both.  */
+	  if ((in->major_version != out->major_version)
+	      || (in->minor_version != out->minor_version))
 	    {
-	      riscv_version_mismatch (ibfd, find_ext, out);
+	      riscv_version_mismatch (ibfd, in, out);
 	      return FALSE;
 	    }
+
+	  riscv_add_subset (&merged_subsets, out->name, out->major_version,
+			    out->minor_version);
+	  out = out->next;
+	  in = in->next;
 	}
-      else
-	riscv_add_subset (&merged_subsets, out->name,
-			  out->major_version, out->minor_version);
     }
 
-  *pin = in;
-  *pout = out;
+  if (in || out) {
+    /* If we're here, either `in' or `out' is running longer than
+       the other. So, we need to append the corresponding tail.  */
+    tail = in ? in : out;
+
+    while (tail)
+      {
+	riscv_add_subset (&merged_subsets, tail->name, tail->major_version,
+			  tail->minor_version);
+	tail = tail->next;
+      }
+  }
+
   return TRUE;
 }
 
@@ -2989,14 +3007,9 @@ riscv_merge_arch_attr_info (bfd *ibfd, char *in_arch, char *out_arch)
   /* Merge standard extension.  */
   if (!riscv_merge_std_ext (ibfd, in_arch, out_arch, &in, &out))
     return NULL;
-  /* Merge non-standard extension.  */
-  if (!riscv_merge_non_std_and_sv_ext (ibfd, &in, &out, riscv_non_std_ext_p))
-    return NULL;
-  /* Merge standard supervisor extension.  */
-  if (!riscv_merge_non_std_and_sv_ext (ibfd, &in, &out, riscv_std_sv_ext_p))
-    return NULL;
-  /* Merge non-standard supervisor extension.  */
-  if (!riscv_merge_non_std_and_sv_ext (ibfd, &in, &out, riscv_non_std_sv_ext_p))
+
+  /* Merge all non-single letter extensions with single call.  */
+  if (!riscv_merge_multi_letter_ext (ibfd, &in, &out))
     return NULL;
 
   if (xlen_in != xlen_out)
diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index 245717f70f..37f78e969b 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1193,7 +1193,7 @@ riscv_parse_std_ext (riscv_parse_subset_t *rps,
     {
       char subset[2] = {0, 0};
 
-      if (*p == 'x' || *p == 's')
+      if (*p == 'x' || *p == 's' || *p == 'z')
 	break;
 
       if (*p == '_')
@@ -1237,28 +1237,58 @@ riscv_parse_std_ext (riscv_parse_subset_t *rps,
   return p;
 }
 
-/* Parsing function for non-standard and supervisor extensions.
+/* Classify the argument 'arch' into one of riscv_isa_ext_class_t.  */
 
-   Return Value:
-     Points to the end of extensions.
+riscv_isa_ext_class_t
+riscv_get_prefix_class (const char *arch)
+{
+  switch (*arch)
+    {
+    case 's':
+      return RV_ISA_CLASS_S;
 
-   Arguments:
-     `rps`: Hooks and status for parsing subset.
-     `march`: Full arch string.
-     `p`: Curent parsing position.
-     `ext_type`: What kind of extensions, 'x', 's' or 'sx'.
-     `ext_type_str`: Full name for kind of extension.  */
+    case 'x': return RV_ISA_CLASS_X;
+    case 'z': return RV_ISA_CLASS_Z;
+    default: return RV_ISA_CLASS_UNKNOWN;
+    }
+}
+
+/* Structure describing parameters to use when parsing a particular
+   riscv_isa_ext_class_t. One of these should be provided for each
+   possible class, except RV_ISA_CLASS_UNKNOWN.  */
+
+typedef struct riscv_parse_config
+{
+  /* Class of the extension. */
+  riscv_isa_ext_class_t class;
+
+  /* Lower-case prefix string for error printing
+     and internal parser usage, e.g. "z", "x".  */
+  const char *prefix;
+
+  /* Predicate which is used for checking whether
+     this is a "known" extension. For 'x',
+     it always returns true (since they are by
+     definition non-standard and cannot be known.  */
+  bfd_boolean (*ext_valid_p) (const char *);
+} riscv_parse_config_t;
+
+/* Parse a generic prefixed extension.
+   march: The full architecture string as passed in by "-march=...".
+   p: Point from which to start parsing the -march string.
+   config: What class of extensions to parse, predicate funcs,
+   and strings to use in error reporting.  */
 
 static const char *
-riscv_parse_sv_or_non_std_ext (riscv_parse_subset_t *rps,
-			       const char *march,
-			       const char *p,
-			       const char *ext_type,
-			       const char *ext_type_str)
+riscv_parse_prefixed_ext (riscv_parse_subset_t *rps,
+			  const char *march,
+			  const char *p,
+			  const riscv_parse_config_t *config)
 {
   unsigned major_version = 0;
   unsigned minor_version = 0;
-  size_t ext_type_len = strlen (ext_type);
+  const char *last_name;
+  riscv_isa_ext_class_t class;
 
   while (*p)
     {
@@ -1268,12 +1298,9 @@ riscv_parse_sv_or_non_std_ext (riscv_parse_subset_t *rps,
 	  continue;
 	}
 
-      if (strncmp (p, ext_type, ext_type_len) != 0)
-	break;
-
-      /* It's non-standard supervisor extension if it prefix with sx.  */
-      if ((ext_type[0] == 's') && (ext_type_len == 1)
-	  && (*(p + 1) == 'x'))
+      /* Assert that the current extension specifier matches our parsing class.  */
+      class = riscv_get_prefix_class (p);
+      if (class != config->class)
 	break;
 
       char *subset = xstrdup (p);
@@ -1294,6 +1321,43 @@ riscv_parse_sv_or_non_std_ext (riscv_parse_subset_t *rps,
 
       *q = '\0';
 
+      /* Check that the name is valid.
+	 For 'x', anything goes but it cannot simply be 'x'.
+	 For 'z', it must be known from a list and also cannot simply be 'z'.
+	 For 's', it must be known from a list and also *can* simply be 's'.  */
+
+      /* Check that the extension name is well-formed.  */
+      if (!config->ext_valid_p (subset))
+	{
+	  rps->error_handler
+	    ("-march=%s: Invalid or unknown %s ISA extension: '%s'",
+	     march, config->prefix, subset);
+	  free (subset);
+	  return NULL;
+	}
+
+      /* Check that the last item is not the same as this.  */
+      last_name = rps->subset_list->tail->name;
+
+      if (!strcasecmp (last_name, subset))
+	{
+	  rps->error_handler ("-march=%s: Duplicate %s ISA extension: \'%s\'",
+			      march, config->prefix, subset);
+	  free (subset);
+	  return NULL;
+	}
+
+      /* Check that we are in alphabetical order within the subset.  */
+      if (!strncasecmp (last_name, config->prefix, 1)
+	  && strcasecmp (last_name, subset) > 0)
+	{
+	  rps->error_handler ("-march=%s: %s ISA extension not in alphabetical order: "
+			      "\'%s\' must come before \'%s\'.",
+			      march, config->prefix, subset, last_name);
+	  free (subset);
+	  return NULL;
+	}
+
       riscv_add_subset (rps->subset_list, subset, major_version, minor_version);
       free (subset);
       p += end_of_version - subset;
@@ -1301,7 +1365,7 @@ riscv_parse_sv_or_non_std_ext (riscv_parse_subset_t *rps,
       if (*p != '\0' && *p != '_')
 	{
 	  rps->error_handler ("-march=%s: %s must seperate with _",
-			      march, ext_type_str);
+			      march, config->prefix);
 	  return NULL;
 	}
     }
@@ -1309,6 +1373,69 @@ riscv_parse_sv_or_non_std_ext (riscv_parse_subset_t *rps,
   return p;
 }
 
+const char * const riscv_std_z_ext_strtab[] =
+  {
+    NULL
+  };
+
+const char * const riscv_std_s_ext_strtab[] =
+  {
+    NULL
+  };
+
+static bfd_boolean
+riscv_multi_letter_ext_valid_p (const char *ext,
+				const char *const *known_exts)
+{
+  for (size_t i = 0; known_exts[i]; ++i)
+    {
+      if (!strcmp (ext, known_exts[i]))
+	return TRUE;
+    }
+
+  return FALSE;
+}
+
+/* Predicator function for x-prefixed extensions.
+   Anything goes, except the literal 'x'.  */
+
+static bfd_boolean
+riscv_ext_x_valid_p (const char *arg)
+{
+  if (!strcasecmp (arg, "x"))
+    return FALSE;
+
+  return TRUE;
+}
+
+/* Predicator functions for z-prefixed extensions.
+   Only known z-extensions are permitted.  */
+
+static bfd_boolean
+riscv_ext_z_valid_p (const char *arg)
+{
+  return riscv_multi_letter_ext_valid_p (arg, riscv_std_z_ext_strtab);
+}
+
+/* Predicator function for 's' prefixed extensions.
+   Must be either literal 's', or a known s-prefixed extension.  */
+
+static bfd_boolean
+riscv_ext_s_valid_p (const char *arg)
+{
+  return riscv_multi_letter_ext_valid_p (arg, riscv_std_s_ext_strtab);
+}
+
+/* Parsing order that is needed for bitmanip.  */
+
+static const riscv_parse_config_t parse_config[] =
+{
+   {RV_ISA_CLASS_S, "s", riscv_ext_s_valid_p},
+   {RV_ISA_CLASS_Z, "z", riscv_ext_z_valid_p},
+   {RV_ISA_CLASS_X, "x", riscv_ext_x_valid_p},
+   {RV_ISA_CLASS_UNKNOWN, NULL, NULL}
+};
+
 /* Function for parsing arch string.
 
    Return Value:
@@ -1347,26 +1474,14 @@ riscv_parse_subset (riscv_parse_subset_t *rps,
   if (p == NULL)
     return FALSE;
 
-  /* Parsing non-standard extension.  */
-  p = riscv_parse_sv_or_non_std_ext (
-	rps, arch, p, "x", "non-standard extension");
-
-  if (p == NULL)
-    return FALSE;
-
-  /* Parsing supervisor extension.  */
-  p = riscv_parse_sv_or_non_std_ext (
-	rps, arch, p, "s", "supervisor extension");
-
-  if (p == NULL)
-    return FALSE;
+  /* Parse the different classes of extensions in the specified order.  */
 
-  /* Parsing non-standard supervisor extension.  */
-  p = riscv_parse_sv_or_non_std_ext (
-	rps, arch, p, "sx", "non-standard supervisor extension");
+  for (size_t i = 0; i < ARRAY_SIZE (parse_config); ++i) {
+    p = riscv_parse_prefixed_ext (rps, arch, p, &parse_config[i]);
 
-  if (p == NULL)
-    return FALSE;
+    if (p == NULL)
+      return FALSE;
+  }
 
   if (*p != '\0')
     {
diff --git a/bfd/elfxx-riscv.h b/bfd/elfxx-riscv.h
index 19f7bd2ecc..12ee7e3276 100644
--- a/bfd/elfxx-riscv.h
+++ b/bfd/elfxx-riscv.h
@@ -86,3 +86,23 @@ riscv_release_subset_list (riscv_subset_list_t *);
 
 extern char *
 riscv_arch_str (unsigned, const riscv_subset_list_t *);
+
+extern const char * const z_ext_strtab[];
+extern const char * const riscv_std_s_ext_strtab[];
+
+/* ISA extension name class. E.g. "zbb" corresponds to RV_ISA_CLASS_Z,
+   "xargs" corresponds to RV_ISA_CLASS_X, etc.  Order is important
+   here.  */
+
+typedef enum riscv_isa_ext_class
+  {
+   RV_ISA_CLASS_S,
+   RV_ISA_CLASS_Z,
+   RV_ISA_CLASS_X,
+   RV_ISA_CLASS_UNKNOWN
+  } riscv_isa_ext_class_t;
+
+/* Classify the argument 'ext' into one of riscv_isa_ext_class_t.  */
+
+riscv_isa_ext_class_t
+riscv_get_prefix_class (const char *ext);
diff --git a/gas/testsuite/gas/riscv/march-fail-s-with-version b/gas/testsuite/gas/riscv/march-fail-s-with-version
new file mode 100644
index 0000000000..a514d4aec7
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-s-with-version
@@ -0,0 +1,2 @@
+Assembler messages:
+.*: Invalid or unknown s ISA extension: 'sfoo'
\ No newline at end of file
diff --git a/gas/testsuite/gas/riscv/march-ok-s-with-version.d b/gas/testsuite/gas/riscv/march-fail-s-with-version.d
similarity index 68%
rename from gas/testsuite/gas/riscv/march-ok-s-with-version.d
rename to gas/testsuite/gas/riscv/march-fail-s-with-version.d
index 6296a15c95..9881c2a0e0 100644
--- a/gas/testsuite/gas/riscv/march-ok-s-with-version.d
+++ b/gas/testsuite/gas/riscv/march-fail-s-with-version.d
@@ -1,5 +1,6 @@
 #as: -march=rv32isfoo3p4
 #objdump: -dr
 #source: empty.s
+#error_output: march-fail-s-with-version.l
 
 .*:     file format elf32-littleriscv
diff --git a/gas/testsuite/gas/riscv/march-fail-s-with-version.l b/gas/testsuite/gas/riscv/march-fail-s-with-version.l
new file mode 100644
index 0000000000..6b1f957276
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-s-with-version.l
@@ -0,0 +1,2 @@
+Assembler messages:
+.*: Invalid or unknown s ISA extension: 'sfoo'
diff --git a/gas/testsuite/gas/riscv/march-ok-s.d b/gas/testsuite/gas/riscv/march-fail-s.d
similarity index 75%
rename from gas/testsuite/gas/riscv/march-ok-s.d
rename to gas/testsuite/gas/riscv/march-fail-s.d
index 7daa0a11d0..ebc8377aaf 100644
--- a/gas/testsuite/gas/riscv/march-ok-s.d
+++ b/gas/testsuite/gas/riscv/march-fail-s.d
@@ -1,5 +1,6 @@
 #as: -march=rv32isfoo
 #objdump: -dr
 #source: empty.s
+#error_output: march-fail-s.l
 
 .*:     file format elf32-littleriscv
diff --git a/gas/testsuite/gas/riscv/march-fail-s.l b/gas/testsuite/gas/riscv/march-fail-s.l
new file mode 100644
index 0000000000..6b1f957276
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-s.l
@@ -0,0 +1,2 @@
+Assembler messages:
+.*: Invalid or unknown s ISA extension: 'sfoo'
diff --git a/gas/testsuite/gas/riscv/march-ok-sx.d b/gas/testsuite/gas/riscv/march-fail-sx.d
similarity index 56%
rename from gas/testsuite/gas/riscv/march-ok-sx.d
rename to gas/testsuite/gas/riscv/march-fail-sx.d
index e2172f2348..144a85c2fb 100644
--- a/gas/testsuite/gas/riscv/march-ok-sx.d
+++ b/gas/testsuite/gas/riscv/march-fail-sx.d
@@ -1,5 +1,6 @@
-#as: -march=rv32isfoo_sxbar
+#as: -march=rv32i_sxbar
 #objdump: -dr
 #source: empty.s
+#error_output: march-fail-sx.l
 
 .*:     file format elf32-littleriscv
diff --git a/gas/testsuite/gas/riscv/march-fail-sx.l b/gas/testsuite/gas/riscv/march-fail-sx.l
new file mode 100644
index 0000000000..b8ead71a3b
--- /dev/null
+++ b/gas/testsuite/gas/riscv/march-fail-sx.l
@@ -0,0 +1,2 @@
+Assembler messages:
+.*: Invalid or unknown s ISA extension: 'sxbar'
-- 
2.17.1