Hi,
this patch removes code handling alias pairs after they was taken over by
symbol table.
It also streamlines how things are output - do_assemble_alias is called when
alias should
be output now, while assemble_alias is the function registering new alias into
symbol
table.
I think I will rename these incrementaly.
Bootstrapped/regtested x86_64-linux
* tree.h (alias_diag_flags): Remove.
(alias_pair): Remove emitted_diags.
(finish_aliases_1, finish_aliases_2, remove_unreachable_alias_pairs,
symbol_alias_set_t, symbol_alias_set_destroy,
symbol_alias_set_contains, propagate_aliases_backward): Remove.
* toplev.c (compile_file): Do not call finish_aliases_2
* cgraphunit.c (cgraph_process_new_functions): Do not call
finish_aliases_1.
(handle_alias_pairs): Output diagnostics about aliases to externals.
(assemble_thunks_and_aliases): Use do_assemble_alias.
(output_weakrefs): Likewise.
(finalize_compilation_unit): Do not call finish_aliases_1.
* ipa.c (symtab_remove_unreachable_nodes): De not call
remove_unreachable_alias_pairs.
* varasm.c (do_assemble_alias): Export.
(symbol_alias_set_create, symbol_alias_set_destroy,
symbol_alias_set_contains,
symbol_alias_set_insert, propagate_aliases_forward,
propagate_aliases_backward,
propagate_aliases_backward, trivially_visible_alias,
trivially_defined_alias,
remove_unreachable_alias_pairs, finish_aliases_1, finish_aliases_2,
assemble_alias): Remove.
* output.h (do_assemble_alias): Declare.
* varpool.c (varpool_remove_unreferenced_decls): Do not call
finish_aliases_1.
Index: tree.h
===================================================================
*** tree.h (revision 187695)
--- tree.h (working copy)
*************** extern const unsigned char tree_code_len
*** 239,263 ****
extern const char *const tree_code_name[];
! /* We have to be able to tell cgraph about the needed-ness of the target
! of an alias. This requires that the decl have been defined. Aliases
! that precede their definition have to be queued for later processing. */
!
! /* The deferred processing proceeds in several passes. We memorize the
! diagnostics emitted for a pair to prevent repeating messages when the
! queue gets re-scanned after possible updates. */
!
! typedef enum {
! ALIAS_DIAG_NONE = 0x0,
! ALIAS_DIAG_TO_UNDEF = 0x1,
! ALIAS_DIAG_TO_EXTERN = 0x2
! } alias_diag_flags;
!
typedef struct GTY(()) alias_pair
{
tree decl;
tree target;
- int emitted_diags; /* alias_diags already emitted for this pair. */
} alias_pair;
/* Define gc'd vector type. */
--- 239,252 ----
extern const char *const tree_code_name[];
! /* When procesing aliases on symtab level, we need the declaration of target.
! For this reason we need to queue aliases and process them after all
declarations
! has been produced. */
!
typedef struct GTY(()) alias_pair
{
tree decl;
tree target;
} alias_pair;
/* Define gc'd vector type. */
*************** extern void mark_decl_referenced (tree);
*** 5686,5709 ****
extern void notice_global_symbol (tree);
extern void set_user_assembler_name (tree, const char *);
extern void process_pending_assemble_externals (void);
- extern void finish_aliases_1 (void);
- extern void finish_aliases_2 (void);
- extern void remove_unreachable_alias_pairs (void);
extern bool decl_replaceable_p (tree);
extern bool decl_binds_to_current_def_p (tree);
-
- /* Derived type for use by compute_visible_aliases and callers. A symbol
- alias set is a pointer set into which we enter IDENTIFIER_NODES bearing
- the canonicalised assembler-level symbol names corresponding to decls
- and their aliases. */
- typedef struct pointer_set_t symbol_alias_set_t;
-
- extern void symbol_alias_set_destroy (symbol_alias_set_t *);
- extern int symbol_alias_set_contains (const symbol_alias_set_t *, tree);
- extern symbol_alias_set_t * propagate_aliases_backward (bool (*)
- (tree, tree, void *),
- void *);
-
/* In stmt.c */
extern void expand_computed_goto (tree);
extern bool parse_output_constraint (const char **, int, int, int,
--- 5675,5682 ----
Index: toplev.c
===================================================================
*** toplev.c (revision 187695)
--- toplev.c (working copy)
*************** compile_file (void)
*** 577,584 ****
basically finished. */
if (in_lto_p || !flag_lto || flag_fat_lto_objects)
{
- finish_aliases_2 ();
-
/* Likewise for mudflap static object registrations. */
if (flag_mudflap)
mudflap_finish_file ();
--- 577,582 ----
Index: cgraphunit.c
===================================================================
*** cgraphunit.c (revision 187695)
--- cgraphunit.c (working copy)
*************** cgraph_process_new_functions (void)
*** 285,291 ****
if (!cgraph_new_nodes)
return false;
- finish_aliases_1 ();
handle_alias_pairs ();
/* Note that this queue may grow as its being processed, as the new
functions may generate new ones. */
--- 285,290 ----
*************** handle_alias_pairs (void)
*** 1068,1073 ****
--- 1070,1087 ----
= lookup_attribute ("weakref",
DECL_ATTRIBUTES (p->decl)) != NULL;
+ if (DECL_EXTERNAL (target_node->symbol.decl)
+ /* We use local aliases for C++ thunks to force the tailcall
+ to bind locally. This is a hack - to keep it working do
+ the following (which is not strictly correct). */
+ && (! TREE_CODE (target_node->symbol.decl) == FUNCTION_DECL
+ || ! DECL_VIRTUAL_P (target_node->symbol.decl))
+ && ! lookup_attribute ("weakref", DECL_ATTRIBUTES (p->decl)))
+ {
+ error ("%q+D aliased to external symbol %qE",
+ p->decl, p->target);
+ }
+
if (TREE_CODE (p->decl) == FUNCTION_DECL
&& target_node && symtab_function_p (target_node))
{
*************** assemble_thunks_and_aliases (struct cgra
*** 1552,1559 ****
/* Force assemble_alias to really output the alias this time instead
of buffering it in same alias pairs. */
TREE_ASM_WRITTEN (alias->thunk.alias) = 1;
! assemble_alias (alias->symbol.decl,
! DECL_ASSEMBLER_NAME (alias->thunk.alias));
assemble_thunks_and_aliases (alias);
TREE_ASM_WRITTEN (alias->thunk.alias) = saved_written;
}
--- 1566,1573 ----
/* Force assemble_alias to really output the alias this time instead
of buffering it in same alias pairs. */
TREE_ASM_WRITTEN (alias->thunk.alias) = 1;
! do_assemble_alias (alias->symbol.decl,
! DECL_ASSEMBLER_NAME (alias->thunk.alias));
assemble_thunks_and_aliases (alias);
TREE_ASM_WRITTEN (alias->thunk.alias) = saved_written;
}
*************** output_weakrefs (void)
*** 1902,1917 ****
if (node->alias && DECL_EXTERNAL (node->symbol.decl)
&& !TREE_ASM_WRITTEN (node->symbol.decl)
&& lookup_attribute ("weakref", DECL_ATTRIBUTES (node->symbol.decl)))
! assemble_alias (node->symbol.decl,
! node->thunk.alias ? DECL_ASSEMBLER_NAME
(node->thunk.alias)
! : get_alias_symbol (node->symbol.decl));
FOR_EACH_VARIABLE (vnode)
if (vnode->alias && DECL_EXTERNAL (vnode->symbol.decl)
&& !TREE_ASM_WRITTEN (vnode->symbol.decl)
&& lookup_attribute ("weakref", DECL_ATTRIBUTES (vnode->symbol.decl)))
! assemble_alias (vnode->symbol.decl,
! vnode->alias_of ? DECL_ASSEMBLER_NAME (vnode->alias_of)
! : get_alias_symbol (vnode->symbol.decl));
}
/* Initialize callgraph dump file. */
--- 1916,1931 ----
if (node->alias && DECL_EXTERNAL (node->symbol.decl)
&& !TREE_ASM_WRITTEN (node->symbol.decl)
&& lookup_attribute ("weakref", DECL_ATTRIBUTES (node->symbol.decl)))
! do_assemble_alias (node->symbol.decl,
! node->thunk.alias ? DECL_ASSEMBLER_NAME
(node->thunk.alias)
! : get_alias_symbol (node->symbol.decl));
FOR_EACH_VARIABLE (vnode)
if (vnode->alias && DECL_EXTERNAL (vnode->symbol.decl)
&& !TREE_ASM_WRITTEN (vnode->symbol.decl)
&& lookup_attribute ("weakref", DECL_ATTRIBUTES (vnode->symbol.decl)))
! do_assemble_alias (vnode->symbol.decl,
! vnode->alias_of ? DECL_ASSEMBLER_NAME (vnode->alias_of)
! : get_alias_symbol (vnode->symbol.decl));
}
/* Initialize callgraph dump file. */
*************** finalize_compilation_unit (void)
*** 2058,2064 ****
finalize_size_functions ();
/* Mark alias targets necessary and emit diagnostics. */
- finish_aliases_1 ();
handle_alias_pairs ();
if (!quiet_flag)
--- 2072,2077 ----
*************** finalize_compilation_unit (void)
*** 2075,2081 ****
cgraph_analyze_functions ();
/* Mark alias targets necessary and emit diagnostics. */
- finish_aliases_1 ();
handle_alias_pairs ();
/* Gimplify and lower thunks. */
--- 2088,2093 ----
Index: ipa.c
===================================================================
*** ipa.c (revision 187695)
--- ipa.c (working copy)
*************** symtab_remove_unreachable_nodes (bool be
*** 454,463 ****
FOR_EACH_DEFINED_FUNCTION (node)
cgraph_propagate_frequency (node);
- /* Reclaim alias pairs for functions that have disappeared from the
- call graph. */
- remove_unreachable_alias_pairs ();
-
return changed;
}
--- 454,459 ----
Index: varasm.c
===================================================================
*** varasm.c (revision 187695)
--- varasm.c (working copy)
*************** VEC(alias_pair,gc) *alias_pairs;
*** 5435,5441 ****
or ASM_OUTPUT_DEF_FROM_DECLS. The function defines the symbol whose
tree node is DECL to have the value of the tree node TARGET. */
! static void
do_assemble_alias (tree decl, tree target)
{
/* Emulated TLS had better not get this var. */
--- 5435,5441 ----
or ASM_OUTPUT_DEF_FROM_DECLS. The function defines the symbol whose
tree node is DECL to have the value of the tree node TARGET. */
! void
do_assemble_alias (tree decl, tree target)
{
/* Emulated TLS had better not get this var. */
*************** do_assemble_alias (tree decl, tree targe
*** 5535,5789 ****
#endif
}
-
- /* Allocate and construct a symbol alias set. */
-
- static symbol_alias_set_t *
- symbol_alias_set_create (void)
- {
- return pointer_set_create ();
- }
-
- /* Destruct and free a symbol alias set. */
-
- void
- symbol_alias_set_destroy (symbol_alias_set_t *aset)
- {
- pointer_set_destroy (aset);
- }
-
- /* Test if a symbol alias set contains a given name. */
-
- int
- symbol_alias_set_contains (const symbol_alias_set_t *aset, tree t)
- {
- /* We accept either a DECL or an IDENTIFIER directly. */
- if (TREE_CODE (t) != IDENTIFIER_NODE)
- t = DECL_ASSEMBLER_NAME (t);
- t = targetm.asm_out.mangle_assembler_name (IDENTIFIER_POINTER (t));
- return pointer_set_contains (aset, t);
- }
-
- /* Enter a new name into a symbol alias set. */
-
- static int
- symbol_alias_set_insert (symbol_alias_set_t *aset, tree t)
- {
- /* We accept either a DECL or an IDENTIFIER directly. */
- if (TREE_CODE (t) != IDENTIFIER_NODE)
- t = DECL_ASSEMBLER_NAME (t);
- t = targetm.asm_out.mangle_assembler_name (IDENTIFIER_POINTER (t));
- return pointer_set_insert (aset, t);
- }
-
- /* IN_SET_P is a predicate function assuming to be taken
- alias_pair->decl, alias_pair->target and DATA arguments.
-
- Compute set of aliases by including everything where TRIVIALLY_VISIBLE
- predeicate is true and propagate across aliases such that when
- alias DECL is included, its TARGET is included too. */
-
- static symbol_alias_set_t *
- propagate_aliases_forward (bool (*in_set_p)
- (tree decl, tree target, void *data),
- void *data)
- {
- symbol_alias_set_t *set;
- unsigned i;
- alias_pair *p;
- bool changed;
-
- set = symbol_alias_set_create ();
- for (i = 0; VEC_iterate (alias_pair, alias_pairs, i, p); ++i)
- if (in_set_p (p->decl, p->target, data))
- symbol_alias_set_insert (set, p->decl);
- do
- {
- changed = false;
- for (i = 0; VEC_iterate (alias_pair, alias_pairs, i, p); ++i)
- if (symbol_alias_set_contains (set, p->decl)
- && !symbol_alias_set_insert (set, p->target))
- changed = true;
- }
- while (changed);
-
- return set;
- }
-
- /* Like propagate_aliases_forward but do backward propagation. */
-
- symbol_alias_set_t *
- propagate_aliases_backward (bool (*in_set_p)
- (tree decl, tree target, void *data),
- void *data)
- {
- symbol_alias_set_t *set;
- unsigned i;
- alias_pair *p;
- bool changed;
-
- /* We have to compute the set of set nodes including aliases
- themselves. */
- set = symbol_alias_set_create ();
- for (i = 0; VEC_iterate (alias_pair, alias_pairs, i, p); ++i)
- if (in_set_p (p->decl, p->target, data))
- symbol_alias_set_insert (set, p->target);
- do
- {
- changed = false;
- for (i = 0; VEC_iterate (alias_pair, alias_pairs, i, p); ++i)
- if (symbol_alias_set_contains (set, p->target)
- && !symbol_alias_set_insert (set, p->decl))
- changed = true;
- }
- while (changed);
-
- return set;
- }
- /* See if the alias is trivially visible. This means
- 1) alias is expoerted from the unit or
- 2) alias is used in the code.
- We assume that unused cgraph/varpool nodes has been
- removed.
- Used as callback for propagate_aliases. */
-
- static bool
- trivially_visible_alias (tree decl, tree target ATTRIBUTE_UNUSED,
- void *data ATTRIBUTE_UNUSED)
- {
- struct cgraph_node *fnode = NULL;
- struct varpool_node *vnode = NULL;
-
- if (!TREE_PUBLIC (decl))
- {
- if (TREE_CODE (decl) == FUNCTION_DECL)
- fnode = cgraph_get_node (decl);
- else
- vnode = varpool_get_node (decl);
- return vnode || fnode;
- }
- else
- return true;
- }
-
- /* See if the target of alias is defined in this unit.
- Used as callback for propagate_aliases. */
-
- static bool
- trivially_defined_alias (tree decl ATTRIBUTE_UNUSED,
- tree target,
- void *data ATTRIBUTE_UNUSED)
- {
- struct cgraph_node *fnode = NULL;
- struct varpool_node *vnode = NULL;
-
- fnode = cgraph_node_for_asm (target);
- vnode = (fnode == NULL) ? varpool_node_for_asm (target) : NULL;
- return (fnode && fnode->analyzed) || (vnode && vnode->finalized);
- }
-
- /* Remove the alias pairing for functions that are no longer in the call
- graph. */
-
- void
- remove_unreachable_alias_pairs (void)
- {
- symbol_alias_set_t *visible;
- unsigned i;
- alias_pair *p;
-
- if (alias_pairs == NULL)
- return;
-
- /* We have to compute the set of visible nodes including aliases
- themselves. */
- visible = propagate_aliases_forward (trivially_visible_alias, NULL);
-
- for (i = 0; VEC_iterate (alias_pair, alias_pairs, i, p); )
- {
- if (!DECL_EXTERNAL (p->decl)
- && !symbol_alias_set_contains (visible, p->decl))
- {
- VEC_unordered_remove (alias_pair, alias_pairs, i);
- continue;
- }
-
- i++;
- }
-
- symbol_alias_set_destroy (visible);
- }
-
-
- /* First pass of completing pending aliases. Make sure that cgraph knows
- which symbols will be required. */
-
- void
- finish_aliases_1 (void)
- {
- symbol_alias_set_t *defined;
- unsigned i;
- alias_pair *p;
-
- if (alias_pairs == NULL)
- return;
-
- /* We have to compute the set of defined nodes including aliases
- themselves. */
- defined = propagate_aliases_backward (trivially_defined_alias, NULL);
-
- FOR_EACH_VEC_ELT (alias_pair, alias_pairs, i, p)
- {
- tree target_decl;
-
- target_decl = find_decl (p->target);
- if (target_decl == NULL)
- {
- if (symbol_alias_set_contains (defined, p->target))
- continue;
-
- if (! (p->emitted_diags & ALIAS_DIAG_TO_UNDEF)
- && ! lookup_attribute ("weakref", DECL_ATTRIBUTES (p->decl)))
- {
- error ("%q+D aliased to undefined symbol %qE",
- p->decl, p->target);
- p->emitted_diags |= ALIAS_DIAG_TO_UNDEF;
- }
- }
- else if (! (p->emitted_diags & ALIAS_DIAG_TO_EXTERN)
- && DECL_EXTERNAL (target_decl)
- /* We use local aliases for C++ thunks to force the tailcall
- to bind locally. This is a hack - to keep it working do
- the following (which is not strictly correct). */
- && (! TREE_CODE (target_decl) == FUNCTION_DECL
- || ! DECL_VIRTUAL_P (target_decl))
- && ! lookup_attribute ("weakref", DECL_ATTRIBUTES (p->decl)))
- {
- error ("%q+D aliased to external symbol %qE",
- p->decl, p->target);
- p->emitted_diags |= ALIAS_DIAG_TO_EXTERN;
- }
- }
-
- symbol_alias_set_destroy (defined);
- }
-
- /* Second pass of completing pending aliases. Emit the actual assembly.
- This happens at the end of compilation and thus it is assured that the
- target symbol has been emitted. */
-
- void
- finish_aliases_2 (void)
- {
- unsigned i;
- alias_pair *p;
-
- FOR_EACH_VEC_ELT (alias_pair, alias_pairs, i, p)
- do_assemble_alias (p->decl, p->target);
-
- VEC_truncate (alias_pair, alias_pairs, 0);
- }
-
/* Emit an assembler directive to make the symbol for DECL an alias to
the symbol for TARGET. */
--- 5535,5540 ----
*************** assemble_alias (tree decl, tree target)
*** 5845,5858 ****
target_decl = find_decl (target);
else
target_decl= NULL;
! if (target_decl && TREE_ASM_WRITTEN (target_decl))
do_assemble_alias (decl, target);
else
{
alias_pair *p = VEC_safe_push (alias_pair, gc, alias_pairs, NULL);
p->decl = decl;
p->target = target;
- p->emitted_diags = ALIAS_DIAG_NONE;
}
}
--- 5596,5609 ----
target_decl = find_decl (target);
else
target_decl= NULL;
! if ((target_decl && TREE_ASM_WRITTEN (target_decl))
! || cgraph_state >= CGRAPH_STATE_EXPANSION)
do_assemble_alias (decl, target);
else
{
alias_pair *p = VEC_safe_push (alias_pair, gc, alias_pairs, NULL);
p->decl = decl;
p->target = target;
}
}
Index: output.h
===================================================================
*** output.h (revision 187695)
--- output.h (working copy)
*************** extern int decode_reg_name (const char *
*** 187,192 ****
--- 187,193 ----
extern int decode_reg_name_and_count (const char *, int *);
extern void assemble_alias (tree, tree);
+ extern void do_assemble_alias (tree, tree);
extern void default_assemble_visibility (tree, int);
Index: varpool.c
===================================================================
*** varpool.c (revision 187695)
--- varpool.c (working copy)
*************** varpool_remove_unreferenced_decls (void)
*** 349,355 ****
if (cgraph_dump_file)
fprintf (cgraph_dump_file, "Trivially needed variables:");
- finish_aliases_1 ();
FOR_EACH_DEFINED_VARIABLE (node)
{
if (node->analyzed
--- 349,354 ----
