Add a generic lhd_simulate_enum_decl

Normally we only create SVE ACLE functions when arm_sve.h is included.
But for LTO we need to do it at start-up, so that the functions are
already defined when streaming in the LTO objects.

One hitch with doing that is that LTO doesn't yet implement the
simulate_enum_decl langhook.  This patch adds a simple default
implementation that it can use.

2020-01-07  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* langhooks-def.h (lhd_simulate_enum_decl): Declare.
	(LANG_HOOKS_SIMULATE_ENUM_DECL): Use it.
	* langhooks.c: Include stor-layout.h.
	(lhd_simulate_enum_decl): New function.
	* config/aarch64/aarch64-sve-builtins.cc (init_builtins): Call
	handle_arm_sve_h for the LTO frontend.
	(register_vector_type): Cope with null returns from pushdecl.

gcc/testsuite/
	* gcc.target/aarch64/sve/pcs/asm_4.c: New test.

From-SVN: r279954

gcc/ChangeLog

@@ -1,3 +1,13 @@
+2020-01-07  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* langhooks-def.h (lhd_simulate_enum_decl): Declare.
+	(LANG_HOOKS_SIMULATE_ENUM_DECL): Use it.
+	* langhooks.c: Include stor-layout.h.
+	(lhd_simulate_enum_decl): New function.
+	* config/aarch64/aarch64-sve-builtins.cc (init_builtins): Call
+	handle_arm_sve_h for the LTO frontend.
+	(register_vector_type): Cope with null returns from pushdecl.
+
 2020-01-07  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* config/aarch64/aarch64-protos.h (aarch64_sve::svbool_type_p)

gcc/config/aarch64/aarch64-sve-builtins.cc

@@ -3044,6 +3044,8 @@ init_builtins ()
 {
   sve_switcher sve;
   register_builtin_types ();
+  if (in_lto_p)
+    handle_arm_sve_h ();
 }
 
 /* Register vector type TYPE under its arm_sve.h name.  */
@@ -3060,7 +3062,8 @@ register_vector_type (vector_type_index type)
      right form, even if it doesn't have the right name.  This should give
      better error recovery behavior than installing error_mark_node or
      installing an incorrect type.  */
-  if (TREE_CODE (decl) == TYPE_DECL
+  if (decl
+      && TREE_CODE (decl) == TYPE_DECL
       && TYPE_MAIN_VARIANT (TREE_TYPE (decl)) == vectype)
     vectype = TREE_TYPE (decl);
   acle_vector_types[0][type] = vectype;

gcc/langhooks-def.h

@@ -54,6 +54,8 @@ extern void lhd_print_error_function (diagnostic_context *,
 extern void lhd_set_decl_assembler_name (tree decl);
 extern void lhd_overwrite_decl_assembler_name (tree decl, tree name);
 extern bool lhd_warn_unused_global_decl (const_tree);
+extern tree lhd_simulate_enum_decl (location_t, const char *,
+				    vec<string_int_pair>);
 extern tree lhd_type_for_size (unsigned precision, int unsignedp);
 extern void lhd_incomplete_type_error (location_t, const_tree, const_tree);
 extern tree lhd_type_promotes_to (tree);
@@ -171,7 +173,7 @@ extern tree lhd_make_node (enum tree_code);
 extern tree lhd_unit_size_without_reusable_padding (tree);
 
 #define LANG_HOOKS_MAKE_TYPE lhd_make_node
-#define LANG_HOOKS_SIMULATE_ENUM_DECL	NULL
+#define LANG_HOOKS_SIMULATE_ENUM_DECL	lhd_simulate_enum_decl
 #define LANG_HOOKS_CLASSIFY_RECORD	NULL
 #define LANG_HOOKS_TYPE_FOR_SIZE	lhd_type_for_size
 #define LANG_HOOKS_INCOMPLETE_TYPE_ERROR lhd_incomplete_type_error

gcc/langhooks.c

@@ -35,6 +35,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-diagnostic.h"
 #include "output.h"
 #include "timevar.h"
+#include "stor-layout.h"
 
 /* Do nothing; in many cases the default hook.  */
 
@@ -473,6 +474,44 @@ lhd_make_node (enum tree_code code)
   return make_node (code);
 }
 
+/* Default implementation of LANG_HOOKS_SIMULATE_ENUM_DECL.  Assume a
+   simple int-based enumerator (which is all the hook can be used for
+   at present) and push each decl individually without any decoration.
+
+   This definition is suitable for LTO and is generic enough that it
+   might be reusable elsewhere.  */
+tree
+lhd_simulate_enum_decl (location_t loc, const char *name,
+			vec<string_int_pair> values)
+{
+  tree enumtype = lang_hooks.types.make_type (ENUMERAL_TYPE);
+  tree enumdecl = build_decl (loc, TYPE_DECL, get_identifier (name), enumtype);
+  TYPE_STUB_DECL (enumtype) = enumdecl;
+
+  tree value_chain = NULL_TREE;
+  string_int_pair *value;
+  unsigned int i;
+  FOR_EACH_VEC_ELT (values, i, value)
+    {
+      tree value_decl = build_decl (loc, CONST_DECL,
+				    get_identifier (value->first), enumtype);
+      DECL_INITIAL (value_decl) = build_int_cst (integer_type_node,
+						 value->second);
+      lang_hooks.decls.pushdecl (value_decl);
+      value_chain = tree_cons (value_decl, DECL_INITIAL (value_decl),
+			       value_chain);
+    }
+
+  TYPE_MIN_VALUE (enumtype) = TYPE_MIN_VALUE (integer_type_node);
+  TYPE_MAX_VALUE (enumtype) = TYPE_MAX_VALUE (integer_type_node);
+  SET_TYPE_ALIGN (enumtype, TYPE_ALIGN (integer_type_node));
+  TYPE_PRECISION (enumtype) = TYPE_PRECISION (integer_type_node);
+  layout_type (enumtype);
+  lang_hooks.decls.pushdecl (enumdecl);
+
+  return enumtype;
+}
+
 /* Default implementation of LANG_HOOKS_TYPE_FOR_SIZE.
    Return an integer type with PRECISION bits of precision,
    that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2020-01-07  Richard Sandiford  <richard.sandiford@arm.com>
+
+	* gcc.target/aarch64/sve/pcs/asm_4.c: New test.
+
 2020-01-07  Richard Sandiford  <richard.sandiford@arm.com>
 
 	* g++.target/aarch64/sve/acle/general-c++/mangle_5.C: New test.

gcc/testsuite/gcc.target/aarch64/sve/pcs/asm_4.c

@@ -0,0 +1,4 @@
+/* { dg-do run { target aarch64_sve_hw } } */
+/* { dg-options "-O2 -flto -ffixed-z0 -ffixed-p0" } */
+
+#include "asm_3.c"