/* Callgraph based analysis of static variables.
- Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
Contributed by Kenneth Zadeck <zadeck@naturalbridge.com>
This file is part of GCC.
#include "pointer-set.h"
#include "ggc.h"
#include "ipa-utils.h"
-#include "c-common.h"
#include "gimple.h"
#include "cgraph.h"
#include "output.h"
#include "diagnostic.h"
#include "langhooks.h"
#include "target.h"
+#include "lto-streamer.h"
+#include "cfgloop.h"
+#include "tree-scalar-evolution.h"
static struct pointer_set_t *visited_nodes;
/* See above. */
enum pure_const_state_e pure_const_state;
/* What user set here; we can be always sure about this. */
- enum pure_const_state_e state_set_in_source;
+ enum pure_const_state_e state_previously_known;
+ bool looping_previously_known;
/* True if the function could possibly infinite loop. There are a
lot of ways that this could be determined. We are pretty
static inline void
check_op (funct_state local, tree t, bool checking_write)
{
- if (TREE_THIS_VOLATILE (t))
+ t = get_base_address (t);
+ if (t && TREE_THIS_VOLATILE (t))
{
local->pure_const_state = IPA_NEITHER;
if (dump_file)
fprintf (dump_file, " Volatile indirect ref is not const/pure\n");
return;
}
+ else if (t
+ && INDIRECT_REF_P (t)
+ && TREE_CODE (TREE_OPERAND (t, 0)) == SSA_NAME
+ && !ptr_deref_may_alias_global_p (TREE_OPERAND (t, 0)))
+ {
+ if (dump_file)
+ fprintf (dump_file, " Indirect ref to local memory is OK\n");
+ return;
+ }
else if (checking_write)
{
local->pure_const_state = IPA_NEITHER;
/* When not in IPA mode, we can still handle self recursion. */
if (!ipa && callee_t == current_function_decl)
local->looping = true;
- /* The callee is either unknown (indirect call) or there is just no
- scannable code for it (external call) . We look to see if there
- are any bits available for the callee (such as by declaration or
- because it is builtin) and process solely on the basis of those
- bits. */
- else if (avail <= AVAIL_OVERWRITABLE || !ipa)
+ /* Either calle is unknown or we are doing local analysis.
+ Look to see if there are any bits available for the callee (such as by
+ declaration or because it is builtin) and process solely on the basis of
+ those bits. */
+ else if (!ipa || !callee_t)
{
if (possibly_throws && flag_non_call_exceptions)
{
{
if (dump_file)
{
- fprintf (dump_file, " can throw externally in region %i\n",
- lookup_stmt_eh_region (call));
+ fprintf (dump_file, " can throw externally to lp %i\n",
+ lookup_stmt_eh_lp (call));
if (callee_t)
fprintf (dump_file, " callee:%s\n",
IDENTIFIER_POINTER (DECL_ASSEMBLER_NAME (callee_t)));
gimple stmt = gsi_stmt (*gsip);
unsigned int i = 0;
+ if (is_gimple_debug (stmt))
+ return;
+
if (dump_file)
{
fprintf (dump_file, " scanning: ");
funct_state l;
basic_block this_block;
- if (cgraph_function_body_availability (fn) <= AVAIL_OVERWRITABLE)
- {
- if (dump_file)
- fprintf (dump_file, "Function is not available or overwrittable; not analyzing.\n");
- return NULL;
- }
-
l = XCNEW (struct funct_state_d);
l->pure_const_state = IPA_CONST;
- l->state_set_in_source = IPA_NEITHER;
+ l->state_previously_known = IPA_NEITHER;
+ l->looping_previously_known = true;
l->looping = false;
l->can_throw = false;
indication of possible infinite loop side
effect. */
if (mark_dfs_back_edges ())
- l->looping = true;
-
+ {
+ /* Preheaders are needed for SCEV to work.
+ Simple lateches and recorded exits improve chances that loop will
+ proved to be finite in testcases such as in loop-15.c and loop-24.c */
+ loop_optimizer_init (LOOPS_NORMAL
+ | LOOPS_HAVE_RECORDED_EXITS);
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ flow_loops_dump (dump_file, NULL, 0);
+ if (mark_irreducible_loops ())
+ {
+ if (dump_file)
+ fprintf (dump_file, " has irreducible loops\n");
+ l->looping = true;
+ }
+ else
+ {
+ loop_iterator li;
+ struct loop *loop;
+ scev_initialize ();
+ FOR_EACH_LOOP (li, loop, 0)
+ if (!finite_loop_p (loop))
+ {
+ if (dump_file)
+ fprintf (dump_file, " can not prove finiteness of loop %i\n", loop->num);
+ l->looping =true;
+ break;
+ }
+ scev_finalize ();
+ }
+ loop_optimizer_finalize ();
+ }
}
if (TREE_READONLY (decl))
{
l->pure_const_state = IPA_CONST;
- l->state_set_in_source = IPA_CONST;
+ l->state_previously_known = IPA_CONST;
if (!DECL_LOOPING_CONST_OR_PURE_P (decl))
- l->looping = false;
+ l->looping = false, l->looping_previously_known = false;
}
if (DECL_PURE_P (decl))
{
if (l->pure_const_state != IPA_CONST)
l->pure_const_state = IPA_PURE;
- l->state_set_in_source = IPA_PURE;
+ l->state_previously_known = IPA_PURE;
if (!DECL_LOOPING_CONST_OR_PURE_P (decl))
- l->looping = false;
+ l->looping = false, l->looping_previously_known = false;
}
if (TREE_NOTHROW (decl))
l->can_throw = false;
static void
add_new_function (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
{
- if (cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE)
+ if (cgraph_function_body_availability (node) < AVAIL_OVERWRITABLE)
return;
/* There are some shared nodes, in particular the initializers on
static declarations. We do not need to scan them more than once
}
\f
-/* Analyze each function in the cgraph to see if it is locally PURE or
- CONST. */
-
-static void
-generate_summary (void)
+static void
+register_hooks (void)
{
- struct cgraph_node *node;
+ static bool init_p = false;
+
+ if (init_p)
+ return;
+
+ init_p = true;
node_removal_hook_holder =
cgraph_add_node_removal_hook (&remove_node_data, NULL);
cgraph_add_node_duplication_hook (&duplicate_node_data, NULL);
function_insertion_hook_holder =
cgraph_add_function_insertion_hook (&add_new_function, NULL);
+}
+
+
+/* Analyze each function in the cgraph to see if it is locally PURE or
+ CONST. */
+
+static void
+generate_summary (void)
+{
+ struct cgraph_node *node;
+
+ register_hooks ();
+
/* There are some shared nodes, in particular the initializers on
static declarations. We do not need to scan them more than once
since all we would be interested in are the addressof
/* Process all of the functions.
- We do NOT process any AVAIL_OVERWRITABLE functions, we cannot
- guarantee that what we learn about the one we see will be true
- for the one that overrides it.
- */
+ We process AVAIL_OVERWRITABLE functions. We can not use the results
+ by default, but the info can be used at LTO with -fwhole-program or
+ when function got clonned and the clone is AVAILABLE. */
+
for (node = cgraph_nodes; node; node = node->next)
- if (cgraph_function_body_availability (node) > AVAIL_OVERWRITABLE)
+ if (cgraph_function_body_availability (node) >= AVAIL_OVERWRITABLE)
set_function_state (node, analyze_function (node, true));
pointer_set_destroy (visited_nodes);
visited_nodes = NULL;
}
+
+/* Serialize the ipa info for lto. */
+
+static void
+pure_const_write_summary (cgraph_node_set set)
+{
+ struct cgraph_node *node;
+ struct lto_simple_output_block *ob
+ = lto_create_simple_output_block (LTO_section_ipa_pure_const);
+ unsigned int count = 0;
+ cgraph_node_set_iterator csi;
+
+ for (csi = csi_start (set); !csi_end_p (csi); csi_next (&csi))
+ {
+ node = csi_node (csi);
+ if (node->analyzed && get_function_state (node) != NULL)
+ count++;
+ }
+
+ lto_output_uleb128_stream (ob->main_stream, count);
+
+ /* Process all of the functions. */
+ for (csi = csi_start (set); !csi_end_p (csi); csi_next (&csi))
+ {
+ node = csi_node (csi);
+ if (node->analyzed && get_function_state (node) != NULL)
+ {
+ struct bitpack_d *bp;
+ funct_state fs;
+ int node_ref;
+ lto_cgraph_encoder_t encoder;
+
+ fs = get_function_state (node);
+
+ encoder = ob->decl_state->cgraph_node_encoder;
+ node_ref = lto_cgraph_encoder_encode (encoder, node);
+ lto_output_uleb128_stream (ob->main_stream, node_ref);
+
+ /* Note that flags will need to be read in the opposite
+ order as we are pushing the bitflags into FLAGS. */
+ bp = bitpack_create ();
+ bp_pack_value (bp, fs->pure_const_state, 2);
+ bp_pack_value (bp, fs->state_previously_known, 2);
+ bp_pack_value (bp, fs->looping_previously_known, 1);
+ bp_pack_value (bp, fs->looping, 1);
+ bp_pack_value (bp, fs->can_throw, 1);
+ lto_output_bitpack (ob->main_stream, bp);
+ bitpack_delete (bp);
+ }
+ }
+
+ lto_destroy_simple_output_block (ob);
+}
+
+
+/* Deserialize the ipa info for lto. */
+
+static void
+pure_const_read_summary (void)
+{
+ struct lto_file_decl_data **file_data_vec = lto_get_file_decl_data ();
+ struct lto_file_decl_data *file_data;
+ unsigned int j = 0;
+
+ register_hooks ();
+ while ((file_data = file_data_vec[j++]))
+ {
+ const char *data;
+ size_t len;
+ struct lto_input_block *ib
+ = lto_create_simple_input_block (file_data,
+ LTO_section_ipa_pure_const,
+ &data, &len);
+ if (ib)
+ {
+ unsigned int i;
+ unsigned int count = lto_input_uleb128 (ib);
+
+ for (i = 0; i < count; i++)
+ {
+ unsigned int index;
+ struct cgraph_node *node;
+ struct bitpack_d *bp;
+ funct_state fs;
+ lto_cgraph_encoder_t encoder;
+
+ fs = XCNEW (struct funct_state_d);
+ index = lto_input_uleb128 (ib);
+ encoder = file_data->cgraph_node_encoder;
+ node = lto_cgraph_encoder_deref (encoder, index);
+ set_function_state (node, fs);
+
+ /* Note that the flags must be read in the opposite
+ order in which they were written (the bitflags were
+ pushed into FLAGS). */
+ bp = lto_input_bitpack (ib);
+ fs->pure_const_state
+ = (enum pure_const_state_e) bp_unpack_value (bp, 2);
+ fs->state_previously_known
+ = (enum pure_const_state_e) bp_unpack_value (bp, 2);
+ fs->looping_previously_known = bp_unpack_value (bp, 1);
+ fs->looping = bp_unpack_value (bp, 1);
+ fs->can_throw = bp_unpack_value (bp, 1);
+ bitpack_delete (bp);
+ }
+
+ lto_destroy_simple_input_block (file_data,
+ LTO_section_ipa_pure_const,
+ ib, data, len);
+ }
+ }
+}
+
+
+static bool
+ignore_edge (struct cgraph_edge *e)
+{
+ return (!e->can_throw_external);
+}
+
+/* Return true if NODE is self recursive function. */
+
+static bool
+self_recursive_p (struct cgraph_node *node)
+{
+ struct cgraph_edge *e;
+ for (e = node->callees; e; e = e->next_callee)
+ if (e->callee == node)
+ return true;
+ return false;
+}
+
/* Produce the global information by preforming a transitive closure
on the local information that was produced by generate_summary.
Note that there is no function_transform pass since this only
cgraph_remove_function_insertion_hook (function_insertion_hook_holder);
cgraph_remove_node_duplication_hook (node_duplication_hook_holder);
cgraph_remove_node_removal_hook (node_removal_hook_holder);
- order_pos = ipa_utils_reduced_inorder (order, true, false);
+ order_pos = ipa_utils_reduced_inorder (order, true, false, NULL);
if (dump_file)
{
dump_cgraph (dump_file);
{
enum pure_const_state_e pure_const_state = IPA_CONST;
bool looping = false;
- bool can_throw = false;
int count = 0;
node = order[i];
if (pure_const_state < w_l->pure_const_state)
pure_const_state = w_l->pure_const_state;
- if (w_l->can_throw)
- can_throw = true;
if (w_l->looping)
looping = true;
+ if (cgraph_function_body_availability (w) == AVAIL_OVERWRITABLE)
+ {
+ looping |= w_l->looping_previously_known;
+ if (pure_const_state < w_l->state_previously_known)
+ pure_const_state = w_l->state_previously_known;
+ }
- if (pure_const_state == IPA_NEITHER
- && can_throw)
+ if (pure_const_state == IPA_NEITHER)
break;
count++;
funct_state y_l = get_function_state (y);
if (pure_const_state < y_l->pure_const_state)
pure_const_state = y_l->pure_const_state;
- if (pure_const_state == IPA_NEITHER
- && can_throw)
+ if (pure_const_state == IPA_NEITHER)
break;
if (y_l->looping)
looping = true;
- if (y_l->can_throw && !TREE_NOTHROW (w->decl)
- /* FIXME: We should check that the throw can get external.
- We also should handle only loops formed by can throw external
- edges. */)
- can_throw = true;
+ }
+ else
+ {
+ int flags = flags_from_decl_or_type (y->decl);
+
+ if (flags & ECF_LOOPING_CONST_OR_PURE)
+ looping = true;
+ if (flags & ECF_CONST)
+ ;
+ else if ((flags & ECF_PURE) && pure_const_state == IPA_CONST)
+ pure_const_state = IPA_PURE;
+ else
+ pure_const_state = IPA_NEITHER, looping = true;
+
}
}
w_info = (struct ipa_dfs_info *) w->aux;
enum pure_const_state_e this_state = pure_const_state;
bool this_looping = looping;
- if (w_l->state_set_in_source != IPA_NEITHER)
- {
- if (this_state > w_l->state_set_in_source)
- this_state = w_l->state_set_in_source;
- this_looping = false;
- }
+ if (w_l->state_previously_known != IPA_NEITHER
+ && this_state > w_l->state_previously_known)
+ this_state = w_l->state_previously_known;
+ if (!this_looping && self_recursive_p (w))
+ this_looping = true;
+ if (!w_l->looping_previously_known)
+ this_looping = false;
/* All nodes within a cycle share the same info. */
w_l->pure_const_state = this_state;
default:
break;
}
+ w_info = (struct ipa_dfs_info *) w->aux;
+ w = w_info->next_cycle;
+ }
+ }
+
+ /* Cleanup. */
+ for (node = cgraph_nodes; node; node = node->next)
+ {
+ /* Get rid of the aux information. */
+ if (node->aux)
+ {
+ w_info = (struct ipa_dfs_info *) node->aux;
+ free (node->aux);
+ node->aux = NULL;
+ }
+ }
+ order_pos = ipa_utils_reduced_inorder (order, true, false, ignore_edge);
+ if (dump_file)
+ {
+ dump_cgraph (dump_file);
+ ipa_utils_print_order(dump_file, "reduced for nothrow", order, order_pos);
+ }
+ /* Propagate the local information thru the call graph to produce
+ the global information. All the nodes within a cycle will have
+ the same info so we collapse cycles first. Then we can do the
+ propagation in one pass from the leaves to the roots. */
+ for (i = 0; i < order_pos; i++ )
+ {
+ bool can_throw = false;
+ node = order[i];
+
+ /* Find the worst state for any node in the cycle. */
+ w = node;
+ while (w)
+ {
+ struct cgraph_edge *e;
+ funct_state w_l = get_function_state (w);
+
+ if (w_l->can_throw
+ || cgraph_function_body_availability (w) == AVAIL_OVERWRITABLE)
+ can_throw = true;
+
+ if (can_throw)
+ break;
+
+ for (e = w->callees; e; e = e->next_callee)
+ {
+ struct cgraph_node *y = e->callee;
+
+ if (cgraph_function_body_availability (y) > AVAIL_OVERWRITABLE)
+ {
+ funct_state y_l = get_function_state (y);
+
+ if (can_throw)
+ break;
+ if (y_l->can_throw && !TREE_NOTHROW (w->decl)
+ && e->can_throw_external)
+ can_throw = true;
+ }
+ else if (e->can_throw_external && !TREE_NOTHROW (y->decl))
+ can_throw = true;
+ }
+ w_info = (struct ipa_dfs_info *) w->aux;
+ w = w_info->next_cycle;
+ }
+
+ /* Copy back the region's pure_const_state which is shared by
+ all nodes in the region. */
+ w = node;
+ while (w)
+ {
+ funct_state w_l = get_function_state (w);
if (!can_throw && !TREE_NOTHROW (w->decl))
{
- /* FIXME: TREE_NOTHROW is not set because passmanager will execute
- verify_ssa and verify_cfg on every function. Before fixup_cfg is done,
- those functions are going to have NOTHROW calls in EH regions reulting
- in ICE. */
+ struct cgraph_edge *e;
+ TREE_NOTHROW (w->decl) = true;
+ for (e = w->callers; e; e = e->next_caller)
+ e->can_throw_external = false;
if (dump_file)
fprintf (dump_file, "Function found to be nothrow: %s\n",
cgraph_node_name (w));
}
+ else if (can_throw && !TREE_NOTHROW (w->decl))
+ w_l->can_throw = true;
w_info = (struct ipa_dfs_info *) w->aux;
w = w_info->next_cycle;
}
free (node->aux);
node->aux = NULL;
}
- if (cgraph_function_body_availability (node) > AVAIL_OVERWRITABLE)
+ if (cgraph_function_body_availability (node) >= AVAIL_OVERWRITABLE)
free (get_function_state (node));
}
&& !(errorcount || sorrycount));
}
-struct ipa_opt_pass pass_ipa_pure_const =
+struct ipa_opt_pass_d pass_ipa_pure_const =
{
{
IPA_PASS,
0 /* todo_flags_finish */
},
generate_summary, /* generate_summary */
- NULL, /* write_summary */
- NULL, /* read_summary */
+ pure_const_write_summary, /* write_summary */
+ pure_const_read_summary, /* read_summary */
NULL, /* function_read_summary */
0, /* TODOs */
NULL, /* function_transform */
fprintf (dump_file, "Function called in recursive cycle; ignoring\n");
return 0;
}
-
- l = analyze_function (cgraph_node (current_function_decl), false);
- if (!l)
+ if (cgraph_function_body_availability (cgraph_node (current_function_decl))
+ <= AVAIL_OVERWRITABLE)
{
if (dump_file)
fprintf (dump_file, "Function has wrong visibility; ignoring\n");
return 0;
}
+ l = analyze_function (cgraph_node (current_function_decl), false);
+
switch (l->pure_const_state)
{
case IPA_CONST:
}
if (!l->can_throw && !TREE_NOTHROW (current_function_decl))
{
- TREE_NOTHROW (current_function_decl) = 1;
+ struct cgraph_edge *e;
+
+ TREE_NOTHROW (current_function_decl) = true;
+ for (e = cgraph_node (current_function_decl)->callers;
+ e; e = e->next_caller)
+ e->can_throw_external = false;
changed = true;
if (dump_file)
fprintf (dump_file, "Function found to be nothrow: %s\n",
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