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Re: PATCH: PR middle-end/20218: Can't use __attribute__ ((visibility ("hidden"))) to hide a symbol
- From: "H. J. Lu" <hjl at lucon dot org>
- To: Steve Ellcey <sje at cup dot hp dot com>
- Cc: gcc-patches at gcc dot gnu dot org, edelsohn at gnu dot org
- Date: Fri, 8 Dec 2006 17:49:17 -0800
- Subject: Re: PATCH: PR middle-end/20218: Can't use __attribute__ ((visibility ("hidden"))) to hide a symbol
- References: <20061207173311.GA4217@us.ibm.com> <200612082140.NAA02410@hpsje.cup.hp.com>
On Fri, Dec 08, 2006 at 01:40:05PM -0800, Steve Ellcey wrote:
> On Thu, Dec 07, 2006 at 06:01:26AM -0800, H. J. Lu wrote:
> > Janis, Steve, can you test it on AIX and HPUX?
>
> I will check it out on HP-UX (had some conflicting merges last night so
> I didn't get results).
>
Here is the current version. Can someone test it on AIX?
H.J.
----
2006-12-07 H.J. Lu <hongjiu.lu@intel.com>
PR middle-end/17982
PR middle-end/20218
* cgraphunit.c (cgraph_optimize): Remove call to
process_pending_assemble_externals.
* config/elfos.h (ASM_OUTPUT_EXTERNAL): New.
* config/ia64/hpux.h (TARGET_ASM_FILE_END): Removed.
* config/ia64/ia64.c (ia64_asm_output_external): Rewritten.
(ia64_hpux_add_extern_decl): Removed.
(ia64_hpux_file_end): Likewise.
(extern_func_list): Likewise.
(extern_func_head): Likewise.
* output.h (assemble_external): Update comments.
(default_elf_asm_output_external): New.
(maybe_assemble_visibility): New.
* toplev.c (compile_file): Update comment.
* varasm.c (assemble_external): Always put it on
pending_assemble_externals.
(maybe_assemble_visibility): Make it extern and return int.
(default_elf_asm_output_external): New.
--- gcc/cgraphunit.c.global 2006-12-05 11:20:12.000000000 -0800
+++ gcc/cgraphunit.c 2006-12-08 09:14:09.000000000 -0800
@@ -1536,8 +1536,6 @@ cgraph_optimize (void)
return;
}
- process_pending_assemble_externals ();
-
/* Frontend may output common variables after the unit has been finalized.
It is safe to deal with them here as they are always zero initialized. */
cgraph_varpool_analyze_pending_decls ();
--- gcc/config/elfos.h.global 2006-12-07 17:07:01.000000000 -0800
+++ gcc/config/elfos.h 2006-12-08 09:16:58.000000000 -0800
@@ -504,3 +504,13 @@ Boston, MA 02110-1301, USA. */
elf_record_gcc_switches function defined in varasm.c. */
#undef TARGET_ASM_RECORD_GCC_SWITCHES
#define TARGET_ASM_RECORD_GCC_SWITCHES elf_record_gcc_switches
+
+/* A C statement (sans semicolon) to output to the stdio stream STREAM
+ any text necessary for declaring the name of an external symbol
+ named NAME whch is referenced in this compilation but not defined.
+ It is needed to properly support non-default visibility. */
+
+#ifndef ASM_OUTPUT_EXTERNAL
+#define ASM_OUTPUT_EXTERNAL(FILE, DECL, NAME) \
+ default_elf_asm_output_external (FILE, DECL, NAME)
+#endif
--- gcc/config/ia64/hpux.h.global 2006-11-18 06:26:07.000000000 -0800
+++ gcc/config/ia64/hpux.h 2006-12-08 09:14:09.000000000 -0800
@@ -144,10 +144,6 @@ do { \
definitions, so do not use them in gthr-posix.h. */
#define GTHREAD_USE_WEAK 0
-/* Put out the needed function declarations at the end. */
-
-#define TARGET_ASM_FILE_END ia64_hpux_file_end
-
#undef CTORS_SECTION_ASM_OP
#define CTORS_SECTION_ASM_OP "\t.section\t.init_array,\t\"aw\",\"init_array\""
--- gcc/config/ia64/ia64.c.global 2006-12-08 09:14:08.000000000 -0800
+++ gcc/config/ia64/ia64.c 2006-12-08 09:14:09.000000000 -0800
@@ -255,10 +255,6 @@ static section *ia64_rwreloc_select_rtx_
unsigned HOST_WIDE_INT)
ATTRIBUTE_UNUSED;
static unsigned int ia64_section_type_flags (tree, const char *, int);
-static void ia64_hpux_add_extern_decl (tree decl)
- ATTRIBUTE_UNUSED;
-static void ia64_hpux_file_end (void)
- ATTRIBUTE_UNUSED;
static void ia64_init_libfuncs (void)
ATTRIBUTE_UNUSED;
static void ia64_hpux_init_libfuncs (void)
@@ -5021,49 +5017,6 @@ ia64_secondary_reload_class (enum reg_cl
}
-/* Emit text to declare externally defined variables and functions, because
- the Intel assembler does not support undefined externals. */
-
-void
-ia64_asm_output_external (FILE *file, tree decl, const char *name)
-{
- int save_referenced;
-
- /* GNU as does not need anything here, but the HP linker does need
- something for external functions. */
-
- if (TARGET_GNU_AS
- && (!TARGET_HPUX_LD
- || TREE_CODE (decl) != FUNCTION_DECL
- || strstr (name, "__builtin_") == name))
- return;
-
- /* ??? The Intel assembler creates a reference that needs to be satisfied by
- the linker when we do this, so we need to be careful not to do this for
- builtin functions which have no library equivalent. Unfortunately, we
- can't tell here whether or not a function will actually be called by
- expand_expr, so we pull in library functions even if we may not need
- them later. */
- if (! strcmp (name, "__builtin_next_arg")
- || ! strcmp (name, "alloca")
- || ! strcmp (name, "__builtin_constant_p")
- || ! strcmp (name, "__builtin_args_info"))
- return;
-
- if (TARGET_HPUX_LD)
- ia64_hpux_add_extern_decl (decl);
- else
- {
- /* assemble_name will set TREE_SYMBOL_REFERENCED, so we must save and
- restore it. */
- save_referenced = TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl));
- if (TREE_CODE (decl) == FUNCTION_DECL)
- ASM_OUTPUT_TYPE_DIRECTIVE (file, name, "function");
- (*targetm.asm_out.globalize_label) (file, name);
- TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)) = save_referenced;
- }
-}
-
/* Parse the -mfixed-range= option string. */
static void
@@ -9175,55 +9128,33 @@ ia64_hpux_function_arg_padding (enum mac
return DEFAULT_FUNCTION_ARG_PADDING (mode, type);
}
-/* Linked list of all external functions that are to be emitted by GCC.
- We output the name if and only if TREE_SYMBOL_REFERENCED is set in
- order to avoid putting out names that are never really used. */
-
-struct extern_func_list GTY(())
-{
- struct extern_func_list *next;
- tree decl;
-};
-
-static GTY(()) struct extern_func_list *extern_func_head;
-
-static void
-ia64_hpux_add_extern_decl (tree decl)
-{
- struct extern_func_list *p = ggc_alloc (sizeof (struct extern_func_list));
-
- p->decl = decl;
- p->next = extern_func_head;
- extern_func_head = p;
-}
-
-/* Print out the list of used global functions. */
+/* Emit text to declare externally defined variables and functions, because
+ the Intel assembler does not support undefined externals. */
-static void
-ia64_hpux_file_end (void)
+void
+ia64_asm_output_external (FILE *file, tree decl, const char *name)
{
- struct extern_func_list *p;
-
- for (p = extern_func_head; p; p = p->next)
- {
- tree decl = p->decl;
- tree id = DECL_ASSEMBLER_NAME (decl);
-
- gcc_assert (id);
-
- if (!TREE_ASM_WRITTEN (decl) && TREE_SYMBOL_REFERENCED (id))
- {
- const char *name = XSTR (XEXP (DECL_RTL (decl), 0), 0);
-
- TREE_ASM_WRITTEN (decl) = 1;
- (*targetm.asm_out.globalize_label) (asm_out_file, name);
- fputs (TYPE_ASM_OP, asm_out_file);
- assemble_name (asm_out_file, name);
- fprintf (asm_out_file, "," TYPE_OPERAND_FMT "\n", "function");
- }
+ /* We output the name if and only if TREE_SYMBOL_REFERENCED is
+ set in order to avoid putting out names that are never really
+ used. */
+ if (TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)))
+ {
+ /* maybe_assemble_visibility will return 1 if the assembler
+ visibility directive is outputed. */
+ int need_visibility = ((*targetm.binds_local_p) (decl)
+ && maybe_assemble_visibility (decl));
+
+ /* GNU as does not need anything here, but the HP linker does
+ need something for external functions. */
+ if ((TARGET_HPUX_LD || !TARGET_GNU_AS)
+ && TREE_CODE (decl) == FUNCTION_DECL)
+ {
+ ASM_OUTPUT_TYPE_DIRECTIVE (file, name, "function");
+ (*targetm.asm_out.globalize_label) (file, name);
+ }
+ else if (need_visibility && !TARGET_GNU_AS)
+ (*targetm.asm_out.globalize_label) (file, name);
}
-
- extern_func_head = 0;
}
/* Set SImode div/mod functions, init_integral_libfuncs only initializes
--- gcc/output.h.global 2006-11-18 06:26:24.000000000 -0800
+++ gcc/output.h 2006-12-08 09:14:09.000000000 -0800
@@ -204,9 +204,9 @@ extern void assemble_variable (tree, int
DONT_OUTPUT_DATA is from assemble_variable. */
extern void align_variable (tree decl, bool dont_output_data);
-/* Output something to declare an external symbol to the assembler.
- (Most assemblers don't need this, so we normally output nothing.)
- Do nothing if DECL is not external. */
+/* Queue for outputing something to declare an external symbol to the
+ assembler. (Most assemblers don't need this, so we normally output
+ nothing.) Do nothing if DECL is not external. */
extern void assemble_external (tree);
/* Assemble code to leave SIZE bytes of zeros. */
@@ -619,6 +619,10 @@ extern void default_file_start (void);
extern void file_end_indicate_exec_stack (void);
extern bool default_valid_pointer_mode (enum machine_mode);
+extern void default_elf_asm_output_external (FILE *file, tree,
+ const char *);
+extern int maybe_assemble_visibility (tree);
+
extern int default_address_cost (rtx);
/* dbxout helper functions */
--- gcc/toplev.c.global 2006-12-07 17:07:01.000000000 -0800
+++ gcc/toplev.c 2006-12-08 09:14:09.000000000 -0800
@@ -1076,9 +1076,7 @@ compile_file (void)
dw2_output_indirect_constants ();
- /* Flush any pending external directives. cgraph did this for
- assemble_external calls from the front end, but the RTL
- expander can also generate them. */
+ /* Flush any pending external directives. */
process_pending_assemble_externals ();
/* Attach a special .ident directive to the end of the file to identify
--- gcc/varasm.c.global 2006-12-07 17:07:01.000000000 -0800
+++ gcc/varasm.c 2006-12-08 09:14:09.000000000 -0800
@@ -126,7 +126,6 @@ static unsigned HOST_WIDE_INT array_size
static unsigned min_align (unsigned, unsigned);
static void output_constructor (tree, unsigned HOST_WIDE_INT, unsigned int);
static void globalize_decl (tree);
-static void maybe_assemble_visibility (tree);
#ifdef BSS_SECTION_ASM_OP
#ifdef ASM_OUTPUT_BSS
static void asm_output_bss (FILE *, tree, const char *,
@@ -1964,11 +1963,10 @@ assemble_external (tree decl ATTRIBUTE_U
if (!DECL_P (decl) || !DECL_EXTERNAL (decl) || !TREE_PUBLIC (decl))
return;
- if (flag_unit_at_a_time)
- pending_assemble_externals = tree_cons (0, decl,
- pending_assemble_externals);
- else
- assemble_external_real (decl);
+ /* We want to output external symbols at very last to check if they
+ are references or not. */
+ pending_assemble_externals = tree_cons (0, decl,
+ pending_assemble_externals);
#endif
}
@@ -5071,13 +5069,18 @@ default_assemble_visibility (tree decl,
/* A helper function to call assemble_visibility when needed for a decl. */
-static void
+int
maybe_assemble_visibility (tree decl)
{
enum symbol_visibility vis = DECL_VISIBILITY (decl);
if (vis != VISIBILITY_DEFAULT)
- targetm.asm_out.visibility (decl, vis);
+ {
+ targetm.asm_out.visibility (decl, vis);
+ return 1;
+ }
+ else
+ return 0;
}
/* Returns 1 if the target configuration supports defining public symbols
@@ -6327,4 +6330,19 @@ elf_record_gcc_switches (print_switch_ty
return 0;
}
+/* Emit text to declare externally defined symbols. It is needed to
+ properly support non-default visibility. */
+void
+default_elf_asm_output_external (FILE *file ATTRIBUTE_UNUSED,
+ tree decl,
+ const char *name ATTRIBUTE_UNUSED)
+{
+ /* We output the name if and only if TREE_SYMBOL_REFERENCED is
+ set in order to avoid putting out names that are never really
+ used. */
+ if (TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl))
+ && targetm.binds_local_p (decl))
+ maybe_assemble_visibility (decl);
+}
+
#include "gt-varasm.h"