Hi, all.
I noticed that defaults.h file contains stub generator functions which
simply call gcc_unreachable. FWIW, Trevor added them to remove some
conditional compilation which depends on HAVE_<insn_name> macros (I mean
something like r223624).
Because we still have ~80 more such conditions in GCC, and probably some
of them will be fixed in the same way, I propose a patch, which allows
to generate required stubs in genflags.
Bootstrapped and regtested on x86_64-unknown-linux-gnu, testing for full
target list in progress. OK for trunk?
--
Regards,
Mikhail Maltsev
gcc/ChangeLog:
2015-06-10 Mikhail Maltsev <malts...@gmail.com>
* defaults.h (gen_simple_return, gen_return, gen_mem_thread_fence,
gen_memory_barrier, gen_mem_signal_fence, gen_load_multiple,
gen_store_multiple, gen_tablejump): Remove. Generate by genflags.
(HAVE_*): Likewise.
* genflags.c (struct stub_info_t): Define.
(stubs): Define variable.
(struct gflg_string_hasher): Define.
(stubs_map): Define variable.
(mark_as_done): New function.
(gen_dummy): New function (move code out of gen_proto, generalize).
(gen_proto): Use gen_dummy.
(gen_insn): Call mark_as_done.
(gen_stub): New function.
(main): Initialize stubs_map, call gen_stubs for missing stubs.
diff --git a/gcc/defaults.h b/gcc/defaults.h
index 057b646..5beddea 100644
--- a/gcc/defaults.h
+++ b/gcc/defaults.h
@@ -1426,96 +1426,6 @@ see the files COPYING3 and COPYING.RUNTIME respectively.
If not, see
#define TARGET_VTABLE_USES_DESCRIPTORS 0
#endif
-#ifndef HAVE_simple_return
-#define HAVE_simple_return 0
-static inline rtx
-gen_simple_return ()
-{
- gcc_unreachable ();
- return NULL;
-}
-#endif
-
-#ifndef HAVE_return
-#define HAVE_return 0
-static inline rtx
-gen_return ()
-{
- gcc_unreachable ();
- return NULL;
-}
-#endif
-
-#ifndef HAVE_epilogue
-#define HAVE_epilogue 0
-static inline rtx
-gen_epilogue ()
-{
- gcc_unreachable ();
- return NULL;
-}
-#endif
-
-#ifndef HAVE_mem_thread_fence
-#define HAVE_mem_thread_fence 0
-static inline rtx
-gen_mem_thread_fence (rtx)
-{
- gcc_unreachable ();
- return NULL;
-}
-#endif
-
-#ifndef HAVE_memory_barrier
-#define HAVE_memory_barrier 0
-static inline rtx
-gen_memory_barrier ()
-{
- gcc_unreachable ();
- return NULL;
-}
-#endif
-
-#ifndef HAVE_mem_signal_fence
-#define HAVE_mem_signal_fence 0
-static inline rtx
-gen_mem_signal_fence (rtx)
-{
- gcc_unreachable ();
- return NULL;
-}
-#endif
-
-#ifndef HAVE_load_multiple
-#define HAVE_load_multiple 0
-static inline rtx
-gen_load_multiple (rtx, rtx, rtx)
-{
- gcc_unreachable ();
- return NULL;
-}
-#endif
-
-#ifndef HAVE_store_multiple
-#define HAVE_store_multiple 0
-static inline rtx
-gen_store_multiple (rtx, rtx, rtx)
-{
- gcc_unreachable ();
- return NULL;
-}
-#endif
-
-#ifndef HAVE_tablejump
-#define HAVE_tablejump 0
-static inline rtx
-gen_tablejump (rtx, rtx)
-{
- gcc_unreachable ();
- return NULL;
-}
-#endif
-
#endif /* GCC_INSN_FLAGS_H */
#endif /* ! GCC_DEFAULTS_H */
diff --git a/gcc/genflags.c b/gcc/genflags.c
index 0da15f1..2a70b56 100644
--- a/gcc/genflags.c
+++ b/gcc/genflags.c
@@ -26,10 +26,65 @@ along with GCC; see the file COPYING3. If not see
#include "tm.h"
#include "rtl.h"
#include "obstack.h"
+#include "hash-map.h"
#include "errors.h"
#include "read-md.h"
#include "gensupport.h"
+/* Structure which holds data, required for generating stub gen_* function. */
+struct stub_info_t
+{
+ /* Instruction name. */
+ const char *name;
+ /* Number of arguments (i.e., instruction operands). */
+ int opno;
+ /* Set to true when generator is output, so no stub is needed. */
+ bool done;
+};
+
+/* These instructions require default stub function. Stubs are never called.
+ They allow to reduce the amount of conditionally-compiled code: if a stub is
+ defined there is no need to guard the call by #ifdef (plain if statement can
+ be used instead). */
+
+#define DEF_STUB(name, opno) { name, opno, false }
+
+static stub_info_t stubs[] = {
+ DEF_STUB ("simple_return", 0),
+ DEF_STUB ("return", 0),
+ DEF_STUB ("epilogue", 0),
+ DEF_STUB ("mem_thread_fence", 1),
+ DEF_STUB ("memory_barrier", 0),
+ DEF_STUB ("mem_signal_fence", 1),
+ DEF_STUB ("load_multiple", 3),
+ DEF_STUB ("store_multiple", 3),
+ DEF_STUB ("tablejump", 2)
+};
+
+#undef DEF_STUB
+
+/* Helper traits for using null-terminated strings as keys in hash map.
+ FIXME: Unify various "string hashers" and move them to hash-map-traits.h.
*/
+struct gflg_string_hasher : default_hashmap_traits
+{
+ typedef const char *value_type;
+ typedef const char *compare_type;
+
+ static inline hashval_t hash (const char *s)
+ {
+ return htab_hash_string (s);
+ }
+
+ static inline bool equal_keys (const char *p1, const char *p2)
+ {
+ return strcmp (p1, p2) == 0;
+ }
+};
+
+/* Mapping from insn name to corresponding stub_info_t entry. */
+static hash_map<const char *, stub_info_t *, gflg_string_hasher>
+ stubs_map (ARRAY_SIZE (stubs), false, false);
+
/* Obstack to remember insns with. */
static struct obstack obstack;
@@ -42,8 +97,18 @@ static int max_opno;
static void max_operand_1 (rtx);
static int num_operands (rtx);
static void gen_proto (rtx);
+static void gen_dummy (const char *, int, bool);
static void gen_macro (const char *, int, int);
static void gen_insn (int, rtx);
+static void gen_stub (const char *, int);
+
+/* Remember that either real generator or dummy called NAME has been output.
*/
+static inline void
+mark_as_done (const char *name)
+{
+ if (stub_info_t **stub = stubs_map.get (name))
+ (*stub)->done = true;
+}
/* Count the number of match_operand's found. */
@@ -119,6 +184,27 @@ gen_macro (const char *name, int real, int expect)
printf ("(%c))\n", i + 'A');
}
+/* Print out a dummy for generator for instruction NAME with NUM arguments
+ which either does nothing, or aborts (depending on UNREACHABLE). */
+
+static void
+gen_dummy (const char *name, int num, bool unreachable)
+{
+ printf ("static inline rtx\ngen_%s (", name);
+
+ if (num > 0)
+ {
+ for (int i = 0; i < num-1; i++)
+ fputs ("rtx, ", stdout);
+ fputs ("rtx", stdout);
+ }
+
+ puts (")\n{");
+ if (unreachable)
+ puts (" gcc_unreachable ();");
+ puts (" return NULL;\n}");
+}
+
/* Print out prototype information for a generator function. If the
insn pattern has been elided, print out a dummy generator that
does nothing. */
@@ -170,20 +256,9 @@ gen_proto (rtx insn)
/* Some back ends want to take the address of generator functions,
so we cannot simply use #define for these dummy definitions. */
if (truth == 0)
- {
- printf ("static inline rtx\ngen_%s", name);
- if (num > 0)
- {
- putchar ('(');
- for (i = 0; i < num-1; i++)
- printf ("rtx ARG_UNUSED (%c), ", 'a' + i);
- printf ("rtx ARG_UNUSED (%c))\n", 'a' + i);
- }
- else
- puts ("(void)");
- puts ("{\n return 0;\n}");
- }
+ gen_dummy (name, num, /*unreachable=*/false);
+ mark_as_done (name);
}
static void
@@ -244,6 +319,19 @@ gen_insn (int line_no, rtx insn)
}
obstack_grow (&obstack, &insn, sizeof (rtx));
+
+ if (truth)
+ mark_as_done (name);
+}
+
+/* Print out stub generator and flag for missing insn. */
+
+static void
+gen_stub (const char *name, int num)
+{
+ gen_dummy (name, num, /*unreachable=*/true);
+ printf ("#define HAVE_%s 0\n", name);
+ printf ("#define CODE_FOR_%s CODE_FOR_nothing\n", name);
}
int
@@ -257,6 +345,9 @@ main (int argc, char **argv)
progname = "genflags";
obstack_init (&obstack);
+ for (unsigned i = 0; i < ARRAY_SIZE (stubs); i++)
+ stubs_map.put (stubs[i].name, &stubs[i]);
+
/* We need to see all the possibilities. Elided insns may have
direct calls to their generators in C code. */
insn_elision = 0;
@@ -290,6 +381,11 @@ main (int argc, char **argv)
for (insn_ptr = insns; *insn_ptr; insn_ptr++)
gen_proto (*insn_ptr);
+ /* Output missing stubs. */
+ for (unsigned i = 0; i < ARRAY_SIZE (stubs); i++)
+ if (!stubs[i].done)
+ gen_stub (stubs[i].name, stubs[i].opno);
+
puts ("\n#endif /* GCC_INSN_FLAGS_H */");
if (have_error || ferror (stdout) || fflush (stdout) || fclose (stdout))
