/* Callgraph handling code.
- Copyright (C) 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2010
+ Free Software Foundation, Inc.
Contributed by Jan Hubicka
This file is part of GCC.
#include "tree.h"
#include "cgraph.h"
#include "langhooks.h"
-#include "diagnostic.h"
+#include "diagnostic-core.h"
#include "hashtab.h"
#include "ggc.h"
#include "timevar.h"
-#include "debug.h"
+#include "debug.h"
#include "target.h"
#include "output.h"
-#include "tree-gimple.h"
+#include "gimple.h"
#include "tree-flow.h"
+#include "flags.h"
/* This file contains basic routines manipulating variable pool.
/* Queue of cgraph nodes scheduled to be lowered and output.
The queue is maintained via mark_needed_node, linked via node->next_needed
- pointer.
+ pointer.
LAST_NEEDED_NODE points to the end of queue, so it can be
maintained in forward order. GTY is needed to make it friendly to
PCH.
-
- During unit-at-a-time compilation we construct the queue of needed variables
+
+ During compilation we construct the queue of needed variables
twice: first time it is during cgraph construction, second time it is at the
end of compilation in VARPOOL_REMOVE_UNREFERENCED_DECLS so we can avoid
optimized out variables being output.
-
- Each variable is thus first analyzed and then later possibly output.
+
+ Each variable is thus first analyzed and then later possibly output.
FIRST_UNANALYZED_NODE points to first node in queue that was not analyzed
yet and is moved via VARPOOL_ANALYZE_PENDING_DECLS. */
-
+
struct varpool_node *varpool_nodes_queue;
static GTY(()) struct varpool_node *varpool_last_needed_node;
static GTY(()) struct varpool_node *varpool_first_unanalyzed_node;
static GTY(()) struct varpool_node *varpool_assembled_nodes_queue;
/* Return name of the node used in debug output. */
-static const char *
+const char *
varpool_node_name (struct varpool_node *node)
{
return lang_hooks.decl_printable_name (node->decl, 2);
return DECL_UID (n1->decl) == DECL_UID (n2->decl);
}
+/* Return varpool node assigned to DECL without creating new one. */
+struct varpool_node *
+varpool_get_node (tree decl)
+{
+ struct varpool_node key, **slot;
+
+ gcc_assert (TREE_CODE (decl) == VAR_DECL
+ && (TREE_STATIC (decl) || DECL_EXTERNAL (decl)));
+
+ if (!varpool_hash)
+ return NULL;
+ key.decl = decl;
+ slot = (struct varpool_node **)
+ htab_find_slot (varpool_hash, &key, NO_INSERT);
+ if (!slot)
+ return NULL;
+ return *slot;
+}
+
/* Return varpool node assigned to DECL. Create new one when needed. */
struct varpool_node *
varpool_node (tree decl)
{
struct varpool_node key, *node, **slot;
- gcc_assert (DECL_P (decl) && TREE_CODE (decl) != FUNCTION_DECL);
+ gcc_assert (TREE_CODE (decl) == VAR_DECL
+ && (TREE_STATIC (decl) || DECL_EXTERNAL (decl)));
if (!varpool_hash)
varpool_hash = htab_create_ggc (10, hash_varpool_node,
htab_find_slot (varpool_hash, &key, INSERT);
if (*slot)
return *slot;
- node = GGC_CNEW (struct varpool_node);
+ node = ggc_alloc_cleared_varpool_node ();
node->decl = decl;
node->order = cgraph_order++;
node->next = varpool_nodes;
+ ipa_empty_ref_list (&node->ref_list);
+ if (varpool_nodes)
+ varpool_nodes->prev = node;
varpool_nodes = node;
*slot = node;
return node;
}
+/* Remove node from the varpool. */
+void
+varpool_remove_node (struct varpool_node *node)
+{
+ void **slot;
+ slot = htab_find_slot (varpool_hash, node, NO_INSERT);
+ gcc_assert (*slot == node);
+ htab_clear_slot (varpool_hash, slot);
+ gcc_assert (!varpool_assembled_nodes_queue);
+ if (!node->alias)
+ while (node->extra_name)
+ varpool_remove_node (node->extra_name);
+ if (node->next)
+ node->next->prev = node->prev;
+ if (node->prev)
+ node->prev->next = node->next;
+ else
+ {
+ if (node->alias && node->extra_name)
+ {
+ gcc_assert (node->extra_name->extra_name == node);
+ node->extra_name->extra_name = node->next;
+ }
+ else
+ {
+ gcc_assert (varpool_nodes == node);
+ varpool_nodes = node->next;
+ }
+ }
+ if (varpool_first_unanalyzed_node == node)
+ varpool_first_unanalyzed_node = node->next_needed;
+ if (node->next_needed)
+ node->next_needed->prev_needed = node->prev_needed;
+ else if (node->prev_needed)
+ {
+ gcc_assert (varpool_last_needed_node);
+ varpool_last_needed_node = node->prev_needed;
+ }
+ if (node->prev_needed)
+ node->prev_needed->next_needed = node->next_needed;
+ else if (node->next_needed)
+ {
+ gcc_assert (varpool_nodes_queue == node);
+ varpool_nodes_queue = node->next_needed;
+ }
+ if (node->same_comdat_group)
+ {
+ struct varpool_node *prev;
+ for (prev = node->same_comdat_group;
+ prev->same_comdat_group != node;
+ prev = prev->same_comdat_group)
+ ;
+ if (node->same_comdat_group == prev)
+ prev->same_comdat_group = NULL;
+ else
+ prev->same_comdat_group = node->same_comdat_group;
+ node->same_comdat_group = NULL;
+ }
+ ipa_remove_all_references (&node->ref_list);
+ ipa_remove_all_refering (&node->ref_list);
+ ggc_free (node);
+}
+
/* Dump given cgraph node. */
void
dump_varpool_node (FILE *f, struct varpool_node *node)
cgraph_function_flags_ready
? cgraph_availability_names[cgraph_variable_initializer_availability (node)]
: "not-ready");
+ if (DECL_ASSEMBLER_NAME_SET_P (node->decl))
+ fprintf (f, " (asm: %s)", IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (node->decl)));
if (DECL_INITIAL (node->decl))
fprintf (f, " initialized");
+ if (TREE_ASM_WRITTEN (node->decl))
+ fprintf (f, " (asm written)");
if (node->needed)
fprintf (f, " needed");
if (node->analyzed)
fprintf (f, " output");
if (node->externally_visible)
fprintf (f, " externally_visible");
+ if (node->in_other_partition)
+ fprintf (f, " in_other_partition");
+ else if (node->used_from_other_partition)
+ fprintf (f, " used_from_other_partition");
fprintf (f, "\n");
+ fprintf (f, " References: ");
+ ipa_dump_references (f, &node->ref_list);
+ fprintf (f, " Refering this var: ");
+ ipa_dump_refering (f, &node->ref_list);
}
/* Dump the variable pool. */
dump_varpool_node (f, node);
}
+/* Dump the variable pool to stderr. */
+
+DEBUG_FUNCTION void
+debug_varpool (void)
+{
+ dump_varpool (stderr);
+}
+
/* Given an assembler name, lookup node. */
struct varpool_node *
varpool_node_for_asm (tree asmname)
varpool_enqueue_needed_node (struct varpool_node *node)
{
if (varpool_last_needed_node)
- varpool_last_needed_node->next_needed = node;
+ {
+ varpool_last_needed_node->next_needed = node;
+ node->prev_needed = varpool_last_needed_node;
+ }
varpool_last_needed_node = node;
node->next_needed = NULL;
if (!varpool_nodes_queue)
void
varpool_mark_needed_node (struct varpool_node *node)
{
+ if (node->alias && node->extra_name)
+ node = node->extra_name;
if (!node->needed && node->finalized
&& !TREE_ASM_WRITTEN (node->decl))
varpool_enqueue_needed_node (node);
}
/* Reset the queue of needed nodes. */
-static void
+void
varpool_reset_queue (void)
{
varpool_last_needed_node = NULL;
/* Determine if variable DECL is needed. That is, visible to something
either outside this translation unit, something magic in the system
- configury, or (if not doing unit-at-a-time) to something we haven't
- seen yet. */
+ configury */
bool
decide_is_variable_needed (struct varpool_node *node, tree decl)
{
- /* If the user told us it is used, then it must be so. */
- if (node->externally_visible || node->force_output)
- return true;
- if (!flag_unit_at_a_time
- && lookup_attribute ("used", DECL_ATTRIBUTES (decl)))
+ if (node->used_from_other_partition)
return true;
-
- /* ??? If the assembler name is set by hand, it is possible to assemble
- the name later after finalizing the function and the fact is noticed
- in assemble_name then. This is arguably a bug. */
- if (DECL_ASSEMBLER_NAME_SET_P (decl)
- && TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)))
- return true;
-
- /* If we decided it was needed before, but at the time we didn't have
- the definition available, then it's still needed. */
- if (node->needed)
+ /* If the user told us it is used, then it must be so. */
+ if ((node->externally_visible && !DECL_COMDAT (decl))
+ || node->force_output)
return true;
/* Externally visible variables must be output. The exception is
COMDAT variables that must be output only when they are needed. */
- if (TREE_PUBLIC (decl) && !flag_whole_program && !DECL_COMDAT (decl)
+ if (TREE_PUBLIC (decl)
+ && !flag_whole_program
+ && !flag_lto
+ && !flag_whopr
+ && !DECL_COMDAT (decl)
&& !DECL_EXTERNAL (decl))
return true;
- /* When emulating tls, we actually see references to the control
- variable, rather than the user-level variable. */
- if (!targetm.have_tls
- && TREE_CODE (decl) == VAR_DECL
- && DECL_THREAD_LOCAL_P (decl))
- {
- tree control = emutls_decl (decl);
- if (decide_is_variable_needed (varpool_node (control), control))
- return true;
- }
-
/* When not reordering top level variables, we have to assume that
we are going to keep everything. */
- if (flag_unit_at_a_time && flag_toplevel_reorder)
+ if (flag_toplevel_reorder)
return false;
/* We want to emit COMDAT variables only when absolutely necessary. */
return true;
}
+/* Return if NODE is constant and its initial value is known (so we can do
+ constant folding). The decision depends on whole program decisions
+ and can not be recomputed at ltrans stage for variables from other
+ partitions. For this reason the new value should be always combined
+ with the previous knowledge. */
+
+bool
+varpool_decide_const_value_known (struct varpool_node *node)
+{
+ tree decl = node->decl;
+
+ gcc_assert (TREE_STATIC (decl) || DECL_EXTERNAL (decl));
+ gcc_assert (TREE_CODE (decl) == VAR_DECL);
+ if (!TREE_READONLY (decl))
+ return false;
+ /* Variables declared 'const' without an initializer
+ have zero as the initializer if they may not be
+ overridden at link or run time. */
+ if (!DECL_INITIAL (decl)
+ && (DECL_EXTERNAL (decl)
+ || DECL_REPLACEABLE_P (decl)))
+ return false;
+
+ /* Variables declared `const' with an initializer are considered
+ to not be overwritable with different initializer by default.
+
+ ??? Previously we behaved so for scalar variables but not for array
+ accesses. */
+ return true;
+}
+
/* Mark DECL as finalized. By finalizing the declaration, frontend instruct the
middle end to output the variable to asm file, if needed or externally
visible. */
{
struct varpool_node *node = varpool_node (decl);
+ gcc_assert (TREE_STATIC (decl));
+
/* The first declaration of a variable that comes through this function
decides whether it is global (in C, has external linkage)
or local (in C, has internal linkage). So do nothing more
if this function has already run. */
if (node->finalized)
{
- if (cgraph_global_info_ready || (!flag_unit_at_a_time && !flag_openmp))
+ if (cgraph_global_info_ready)
varpool_assemble_pending_decls ();
return;
}
if (node->needed)
varpool_enqueue_needed_node (node);
node->finalized = true;
+ if (TREE_THIS_VOLATILE (decl) || DECL_PRESERVE_P (decl))
+ node->force_output = true;
if (decide_is_variable_needed (node, decl))
varpool_mark_needed_node (node);
there. */
else if (TREE_PUBLIC (decl) && !DECL_COMDAT (decl) && !DECL_EXTERNAL (decl))
varpool_mark_needed_node (node);
- if (cgraph_global_info_ready || (!flag_unit_at_a_time && !flag_openmp))
+ node->const_value_known |= varpool_decide_const_value_known (node);
+ if (cgraph_global_info_ready)
varpool_assemble_pending_decls ();
}
varpool_analyze_pending_decls (void)
{
bool changed = false;
- timevar_push (TV_CGRAPH);
+ timevar_push (TV_VARPOOL);
while (varpool_first_unanalyzed_node)
{
- tree decl = varpool_first_unanalyzed_node->decl;
+ struct varpool_node *node = varpool_first_unanalyzed_node, *next;
+ tree decl = node->decl;
+ bool analyzed = node->analyzed;
varpool_first_unanalyzed_node->analyzed = true;
varpool_first_unanalyzed_node = varpool_first_unanalyzed_node->next_needed;
- /* Compute the alignment early so function body expanders are
- already informed about increased alignment. */
- align_variable (decl, 0);
-
+ /* When reading back varpool at LTO time, we re-construct the queue in order
+ to have "needed" list right by inserting all needed nodes into varpool.
+ We however don't want to re-analyze already analyzed nodes. */
+ if (!analyzed)
+ {
+ gcc_assert (!in_lto_p || cgraph_function_flags_ready);
+ /* Compute the alignment early so function body expanders are
+ already informed about increased alignment. */
+ align_variable (decl, 0);
+ }
if (DECL_INITIAL (decl))
- record_references_in_initializer (decl);
+ record_references_in_initializer (decl, analyzed);
+ if (node->same_comdat_group)
+ {
+ for (next = node->same_comdat_group;
+ next != node;
+ next = next->same_comdat_group)
+ varpool_mark_needed_node (next);
+ }
changed = true;
}
- timevar_pop (TV_CGRAPH);
+ timevar_pop (TV_VARPOOL);
return changed;
}
if (!TREE_ASM_WRITTEN (decl)
&& !node->alias
+ && !node->in_other_partition
&& !DECL_EXTERNAL (decl)
&& (TREE_CODE (decl) != VAR_DECL || !DECL_HAS_VALUE_EXPR_P (decl)))
{
assemble_variable (decl, 0, 1, 0);
- return TREE_ASM_WRITTEN (decl);
+ if (TREE_ASM_WRITTEN (decl))
+ {
+ struct varpool_node *alias;
+
+ node->next_needed = varpool_assembled_nodes_queue;
+ node->prev_needed = NULL;
+ if (varpool_assembled_nodes_queue)
+ varpool_assembled_nodes_queue->prev_needed = node;
+ varpool_assembled_nodes_queue = node;
+ node->finalized = 1;
+
+ /* Also emit any extra name aliases. */
+ for (alias = node->extra_name; alias; alias = alias->next)
+ {
+ /* Update linkage fields in case they've changed. */
+ DECL_WEAK (alias->decl) = DECL_WEAK (decl);
+ TREE_PUBLIC (alias->decl) = TREE_PUBLIC (decl);
+ DECL_VISIBILITY (alias->decl) = DECL_VISIBILITY (decl);
+ assemble_alias (alias->decl, DECL_ASSEMBLER_NAME (decl));
+ }
+
+ return true;
+ }
}
return false;
varpool_reset_queue ();
- if (errorcount || sorrycount)
+ if (seen_error ())
return;
while (node)
{
bool changed = false;
- if (errorcount || sorrycount)
+ if (seen_error ())
return false;
+ timevar_push (TV_VAROUT);
/* EH might mark decls as needed during expansion. This should be safe since
we don't create references to new function, but it should not be used
elsewhere. */
varpool_nodes_queue = varpool_nodes_queue->next_needed;
if (varpool_assemble_decl (node))
+ changed = true;
+ else
{
- changed = true;
- node->next_needed = varpool_assembled_nodes_queue;
- varpool_assembled_nodes_queue = node;
- node->finalized = 1;
+ node->prev_needed = NULL;
+ node->next_needed = NULL;
}
- else
- node->next_needed = NULL;
}
/* varpool_nodes_queue is now empty, clear the pointer to the last element
in the queue. */
varpool_last_needed_node = NULL;
+ timevar_pop (TV_VAROUT);
return changed;
}
-/* Output all variables enqueued to be assembled. */
+/* Remove all elements from the queue so we can re-use it for debug output. */
void
-varpool_output_debug_info (void)
+varpool_empty_needed_queue (void)
{
- timevar_push (TV_SYMOUT);
- if (errorcount == 0 && sorrycount == 0)
- while (varpool_assembled_nodes_queue)
- {
- struct varpool_node *node = varpool_assembled_nodes_queue;
-
- /* Local static variables are never seen by check_global_declarations
- so we need to output debug info by hand. */
- if (DECL_CONTEXT (node->decl)
- && (TREE_CODE (DECL_CONTEXT (node->decl)) == BLOCK
- || TREE_CODE (DECL_CONTEXT (node->decl)) == FUNCTION_DECL)
- && errorcount == 0 && sorrycount == 0)
- (*debug_hooks->global_decl) (node->decl);
- varpool_assembled_nodes_queue = node->next_needed;
- node->next_needed = 0;
- }
- timevar_pop (TV_SYMOUT);
+ /* EH might mark decls as needed during expansion. This should be safe since
+ we don't create references to new function, but it should not be used
+ elsewhere. */
+ varpool_analyze_pending_decls ();
+
+ while (varpool_nodes_queue)
+ {
+ struct varpool_node *node = varpool_nodes_queue;
+ varpool_nodes_queue = varpool_nodes_queue->next_needed;
+ node->next_needed = NULL;
+ node->prev_needed = NULL;
+ }
+ /* varpool_nodes_queue is now empty, clear the pointer to the last element
+ in the queue. */
+ varpool_last_needed_node = NULL;
}
/* Create a new global variable of type TYPE. */
return new_node->decl;
}
+/* Attempt to mark ALIAS as an alias to DECL. Return TRUE if successful.
+ Extra name aliases are output whenever DECL is output. */
+
+bool
+varpool_extra_name_alias (tree alias, tree decl)
+{
+ struct varpool_node key, *alias_node, *decl_node, **slot;
+
+#ifndef ASM_OUTPUT_DEF
+ /* If aliases aren't supported by the assembler, fail. */
+ return false;
+#endif
+
+ gcc_assert (TREE_CODE (decl) == VAR_DECL);
+ gcc_assert (TREE_CODE (alias) == VAR_DECL);
+ /* Make sure the hash table has been created. */
+ decl_node = varpool_node (decl);
+
+ key.decl = alias;
+
+ slot = (struct varpool_node **) htab_find_slot (varpool_hash, &key, INSERT);
+
+ /* If the varpool_node has been already created, fail. */
+ if (*slot)
+ return false;
+
+ alias_node = ggc_alloc_cleared_varpool_node ();
+ alias_node->decl = alias;
+ alias_node->alias = 1;
+ alias_node->extra_name = decl_node;
+ alias_node->next = decl_node->extra_name;
+ ipa_empty_ref_list (&alias_node->ref_list);
+ if (decl_node->extra_name)
+ decl_node->extra_name->prev = alias_node;
+ decl_node->extra_name = alias_node;
+ *slot = alias_node;
+ return true;
+}
+
#include "gt-varpool.h"
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