[BRIGFE] Changed pure attributes to const for the brig-builtins

that are actually const.

Also:
* Fixed brig-lang.c such that the builtin attributes actually
  have effect...
* Made -O3 the default optimization level for BRIG.

From-SVN: r253254

gcc/ChangeLog

+2017-09-28  Henry Linjamäki  <henry.linjamaki@parmance.com>
+
+	* brig-builtins.def: Change pure attributes to const.
+
 2017-09-28  Joseph Myers  <joseph@codesourcery.com>
 
 	* config.gcc (default_gnu_indirect_function): Default to yes for

gcc/brig/ChangeLog

+2017-09-28  Henry Linjamäki  <henry.linjamaki@parmance.com>
+
+	* brig-lang.c: Added function attributes and their handlers.
+	Make BRIGFE 3-level optimize by default.
+
 2017-09-27  Pekka Jääskeläinen  <pekka.jaaskelainen@parmance.com>
 
 	* brig-lang.c: Improved support for function and module scope

gcc/brig/brig-lang.c

@@ -51,6 +51,12 @@ along with GCC; see the file COPYING3.  If not see
 #include "brig-c.h"
 #include "brig-builtins.h"
 
+static tree handle_leaf_attribute (tree *, tree, tree, int, bool *);
+static tree handle_const_attribute (tree *, tree, tree, int, bool *);
+static tree handle_pure_attribute (tree *, tree, tree, int, bool *);
+static tree handle_nothrow_attribute (tree *, tree, tree, int, bool *);
+static tree handle_returns_twice_attribute (tree *, tree, tree, int, bool *);
+
 /* This file is based on Go frontent'd go-lang.c and gogo-tree.cc.  */
 
 /* If -v set.  */
@@ -128,6 +134,8 @@ brig_langhook_init_options_struct (struct gcc_options *opts)
 
   opts->x_flag_finite_math_only = 0;
   opts->x_flag_signed_zeros = 1;
+
+  opts->x_optimize = 3;
 }
 
 /* Handle Brig specific options.  Return 0 if we didn't do anything.  */
@@ -432,6 +440,124 @@ brig_localize_identifier (const char *ident)
   return identifier_to_locale (ident);
 }
 
+/* Define supported attributes and their handlers. Code copied from
+   lto-lang.c */
+
+/* Table of machine-independent attributes supported in GIMPLE.  */
+const struct attribute_spec brig_attribute_table[] =
+{
+  /* { name, min_len, max_len, decl_req, type_req, fn_type_req, handler,
+       do_diagnostic } */
+  { "leaf",		      0, 0, true,  false, false,
+			      handle_leaf_attribute, false },
+  { "const",                  0, 0, true,  false, false,
+			      handle_const_attribute, false },
+  { "pure",                   0, 0, true,  false, false,
+			      handle_pure_attribute, false },
+  { "nothrow",                0, 0, true,  false, false,
+			      handle_nothrow_attribute, false },
+  { "returns_twice",          0, 0, true,  false, false,
+			      handle_returns_twice_attribute, false },
+  { NULL,                     0, 0, false, false, false, NULL, false }
+};
+
+/* Attribute handlers.  */
+/* Handle a "leaf" attribute; arguments as in
+   struct attribute_spec.handler.  */
+
+static tree
+handle_leaf_attribute (tree *node, tree name,
+		       tree ARG_UNUSED (args),
+		       int ARG_UNUSED (flags), bool *no_add_attrs)
+{
+  if (TREE_CODE (*node) != FUNCTION_DECL)
+    {
+      warning (OPT_Wattributes, "%qE attribute ignored", name);
+      *no_add_attrs = true;
+    }
+  if (!TREE_PUBLIC (*node))
+    {
+      warning (OPT_Wattributes,
+	       "%qE attribute has no effect on unit local functions", name);
+      *no_add_attrs = true;
+    }
+
+  return NULL_TREE;
+}
+
+/* Handle a "const" attribute; arguments as in
+   struct attribute_spec.handler.  */
+
+static tree
+handle_const_attribute (tree *node, tree ARG_UNUSED (name),
+			tree ARG_UNUSED (args), int ARG_UNUSED (flags),
+			bool * ARG_UNUSED (no_add_attrs))
+{
+  tree type = TREE_TYPE (*node);
+
+  /* See FIXME comment on noreturn in c_common_attribute_table.  */
+  if (TREE_CODE (*node) == FUNCTION_DECL)
+    TREE_READONLY (*node) = 1;
+  else if (TREE_CODE (type) == POINTER_TYPE
+	   && TREE_CODE (TREE_TYPE (type)) == FUNCTION_TYPE)
+    TREE_TYPE (*node)
+      = build_pointer_type
+	(build_type_variant (TREE_TYPE (type), 1,
+			     TREE_THIS_VOLATILE (TREE_TYPE (type))));
+  else
+    gcc_unreachable ();
+
+  return NULL_TREE;
+}
+
+/* Handle a "pure" attribute; arguments as in
+   struct attribute_spec.handler.  */
+
+static tree
+handle_pure_attribute (tree *node, tree ARG_UNUSED (name),
+		       tree ARG_UNUSED (args), int ARG_UNUSED (flags),
+		       bool * ARG_UNUSED (no_add_attrs))
+{
+  if (TREE_CODE (*node) == FUNCTION_DECL)
+    DECL_PURE_P (*node) = 1;
+  else
+    gcc_unreachable ();
+
+  return NULL_TREE;
+}
+
+/* Handle a "nothrow" attribute; arguments as in
+   struct attribute_spec.handler.  */
+
+static tree
+handle_nothrow_attribute (tree *node, tree ARG_UNUSED (name),
+			  tree ARG_UNUSED (args), int ARG_UNUSED (flags),
+			  bool * ARG_UNUSED (no_add_attrs))
+{
+  if (TREE_CODE (*node) == FUNCTION_DECL)
+    TREE_NOTHROW (*node) = 1;
+  else
+    gcc_unreachable ();
+
+  return NULL_TREE;
+}
+
+/* Handle a "returns_twice" attribute.  */
+
+static tree
+handle_returns_twice_attribute (tree *node, tree ARG_UNUSED (name),
+				tree ARG_UNUSED (args),
+				int ARG_UNUSED (flags),
+				bool * ARG_UNUSED (no_add_attrs))
+{
+  gcc_assert (TREE_CODE (*node) == FUNCTION_DECL);
+
+  DECL_IS_RETURNS_TWICE (*node) = 1;
+
+  return NULL_TREE;
+}
+
+
 /* Built-in initialization code cribbed from lto-lang.c which cribbed it
    from c-common.c.  */
 
@@ -814,6 +940,10 @@ brig_langhook_init (void)
 #define LANG_HOOKS_GIMPLIFY_EXPR brig_langhook_gimplify_expr
 #define LANG_HOOKS_EH_PERSONALITY brig_langhook_eh_personality
 
+/* Attribute hooks.  */
+#undef LANG_HOOKS_COMMON_ATTRIBUTE_TABLE
+#define LANG_HOOKS_COMMON_ATTRIBUTE_TABLE brig_attribute_table
+
 struct lang_hooks lang_hooks = LANG_HOOKS_INITIALIZER;
 
 #include "gt-brig-brig-lang.h"