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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: gcc-patches at gcc dot gnu dot org
- Date: Tue, 5 Dec 2006 15:57:04 -0800
- Subject: PATCH: PR middle-end/20218: Can't use __attribute__ ((visibility ("hidden"))) to hide a symbol
Here is the updated patch. It removes process_pending_assemble_externals
call in cgraph_optimize and uses ASM_OUTPUT_EXTERNAL to output hidden
references or definitions.
I changed maybe_assemble_visibility to return int so that we only
generate ".globl" directive for hidden references, which is needed
for Intel ia64 assembler.
H.J.
----
2006-12-05 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.
* varasm.c (maybe_assemble_visibility): Make it extern and
return int.
(default_elf_asm_output_external): New.
--- gcc/cgraphunit.c.global 2006-05-19 06:21:09.000000000 -0700
+++ gcc/cgraphunit.c 2006-05-19 06:19:49.000000000 -0700
@@ -1394,8 +1394,6 @@ 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 2006-03-03 11:40:17.000000000 -0800
+++ gcc/config/elfos.h 2006-05-19 06:17:57.000000000 -0700
@@ -489,3 +489,13 @@ Boston, MA 02110-1301, USA. */
fprintf ((FILE), "\"\n"); \
} \
while (0)
+
+/* 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 2005-12-17 10:07:59.000000000 -0800
+++ gcc/config/ia64/hpux.h 2006-05-19 06:17:57.000000000 -0700
@@ -141,10 +141,6 @@ 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 2006-05-19 06:17:07.000000000 -0700
+++ gcc/config/ia64/ia64.c 2006-05-19 06:17:57.000000000 -0700
@@ -254,10 +254,6 @@ 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)
@@ -4995,49 +4991,6 @@ 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
@@ -9149,55 +9102,33 @@ 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 2006-03-07 07:16:01.000000000 -0800
+++ gcc/output.h 2006-05-19 06:17:57.000000000 -0700
@@ -200,9 +200,9 @@ extern void assemble_end_function (tree,
initial value (that will be done by the caller). */
extern void assemble_variable (tree, int, int, int);
-/* 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. */
@@ -608,6 +608,10 @@ 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/varasm.c.global 2006-04-25 18:49:52.000000000 -0700
+++ gcc/varasm.c 2006-05-19 06:17:57.000000000 -0700
@@ -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 *,
@@ -5050,13 +5049,18 @@ 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
@@ -6205,4 +6209,19 @@ output_object_blocks (void)
htab_traverse (object_block_htab, output_object_block_htab, NULL);
}
+/* 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"