/* Callgraph handling code.
- Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008
+ Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2010
Free Software Foundation, Inc.
Contributed by Jan Hubicka
#include "hashtab.h"
#include "ggc.h"
#include "timevar.h"
-#include "debug.h"
+#include "debug.h"
#include "target.h"
#include "output.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 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);
dump_varpool_node (f, node);
}
+/* Dump the variable pool to stderr. */
+
+void
+debug_varpool (void)
+{
+ dump_varpool (stderr);
+}
+
/* Given an assembler name, lookup node. */
struct varpool_node *
varpool_node_for_asm (tree asmname)
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);
bool
decide_is_variable_needed (struct varpool_node *node, tree decl)
{
+ /* We do not track variable references at all and thus have no idea if the
+ variable was referenced in some other partition or not.
+ FIXME: We really need address taken edges in callgraph and varpool to
+ drive WPA and decide whether other partition might reference it or not. */
+ if (flag_ltrans)
+ return true;
/* If the user told us it is used, then it must be so. */
- if (node->externally_visible || node->force_output)
+ if ((node->externally_visible && !DECL_COMDAT (decl))
+ || node->force_output)
return true;
/* ??? If the assembler name is set by hand, it is possible to assemble
&& 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)
- 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;
{
struct varpool_node *node = varpool_node (decl);
+ /* FIXME: We don't really stream varpool datastructure and instead rebuild it
+ by varpool_finalize_decl. This is not quite correct since this way we can't
+ attach any info to varpool. Eventually we will want to stream varpool nodes
+ and the flags.
+
+ For the moment just prevent analysis of varpool nodes to happen again, so
+ we will re-try to compute "address_taken" flag of varpool that breaks
+ in presence of clones. */
+ if (in_lto_p)
+ node->analyzed = true;
+
/* 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
while (varpool_first_unanalyzed_node)
{
tree decl = varpool_first_unanalyzed_node->decl;
+ bool analyzed = varpool_first_unanalyzed_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);
+ /* 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);
changed = true;
}
timevar_pop (TV_CGRAPH);
assemble_variable (decl, 0, 1, 0);
if (TREE_ASM_WRITTEN (decl))
{
+ struct varpool_node *alias;
+
node->next_needed = varpool_assembled_nodes_queue;
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;
}
}
varpool_last_needed_node = NULL;
}
-/* Output all variables enqueued to be assembled. */
-void
-varpool_output_debug_info (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);
-}
-
/* Create a new global variable of type TYPE. */
tree
add_new_static_var (tree 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_CNEW (struct varpool_node);
+ alias_node->decl = alias;
+ alias_node->alias = 1;
+ alias_node->extra_name = decl_node;
+ alias_node->next = decl_node->extra_name;
+ decl_node->extra_name = alias_node;
+ *slot = alias_node;
+ return true;
+}
+
#include "gt-varpool.h"
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