/* Callgraph based analysis of static variables.
- Copyright (C) 2004, 2005, 2007 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
Contributed by Kenneth Zadeck <zadeck@naturalbridge.com>
This file is part of GCC.
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
-/* This file mark functions as being either const (TREE_READONLY) or
- pure (DECL_IS_PURE).
+/* This file marks functions as being either const (TREE_READONLY) or
+ pure (DECL_PURE_P). It can also set a variant of these that
+ are allowed to loop indefinitely (DECL_LOOPING_CONST_PURE_P).
This must be run after inlining decisions have been made since
otherwise, the local sets will not contain information that is
#include "ggc.h"
#include "ipa-utils.h"
#include "c-common.h"
-#include "tree-gimple.h"
+#include "gimple.h"
#include "cgraph.h"
#include "output.h"
#include "flags.h"
IPA_NEITHER
};
-/* Holder inserted into the ipa_dfs_info aux field to hold the
- const_state. */
+/* Holder for the const_state. There is one of these per function
+ decl. */
struct funct_state_d
{
+ /* See above. */
enum pure_const_state_e pure_const_state;
- bool state_set_in_source;
+
+ /* True if the function could possibly infinite loop. There are a
+ lot of ways that this could be determined. We are pretty
+ conservative here. While it is possible to cse pure and const
+ calls, it is not legal to have dce get rid of the call if there
+ is a possibility that the call could infinite loop since this is
+ a behavioral change. */
+ bool looping;
+
+ /* If the state of the function was set in the source, then assume
+ that it was done properly even if the analysis we do would be
+ more pessimestic. */
+ bool state_set_in_source;
};
typedef struct funct_state_d * funct_state;
+/* The storage of the funct_state is abstracted because there is the
+ possibility that it may be desirable to move this to the cgraph
+ local info. */
+
+/* Array, indexed by cgraph node uid, of function states. */
+
+DEF_VEC_P (funct_state);
+DEF_VEC_ALLOC_P (funct_state, heap);
+static VEC (funct_state, heap) *funct_state_vec;
+
+/* Holders of ipa cgraph hooks: */
+static struct cgraph_node_hook_list *function_insertion_hook_holder;
+static struct cgraph_2node_hook_list *node_duplication_hook_holder;
+static struct cgraph_node_hook_list *node_removal_hook_holder;
+
+/* Init the function state. */
+
+static void
+finish_state (void)
+{
+ free (funct_state_vec);
+}
+
+
/* Return the function state from NODE. */
static inline funct_state
get_function_state (struct cgraph_node *node)
{
- struct ipa_dfs_info * info = (struct ipa_dfs_info *) node->aux;
- return (funct_state) info->aux;
+ if (!funct_state_vec
+ || VEC_length (funct_state, funct_state_vec) <= (unsigned int)node->uid)
+ return NULL;
+ return VEC_index (funct_state, funct_state_vec, node->uid);
+}
+
+/* Set the function state S for NODE. */
+
+static inline void
+set_function_state (struct cgraph_node *node, funct_state s)
+{
+ if (!funct_state_vec
+ || VEC_length (funct_state, funct_state_vec) <= (unsigned int)node->uid)
+ VEC_safe_grow_cleared (funct_state, heap, funct_state_vec, node->uid + 1);
+ VEC_replace (funct_state, funct_state_vec, node->uid, s);
}
-/* Check to see if the use (or definition when CHECHING_WRITE is true)
+/* Check to see if the use (or definition when CHECKING_WRITE is true)
variable T is legal in a function that is either pure or const. */
static inline void
if (lookup_attribute ("used", DECL_ATTRIBUTES (t)))
{
local->pure_const_state = IPA_NEITHER;
+ local->looping = false;
return;
}
if (TREE_THIS_VOLATILE (t))
{
local->pure_const_state = IPA_NEITHER;
+ local->looping = false;
return;
}
if (checking_write)
{
local->pure_const_state = IPA_NEITHER;
+ local->looping = false;
return;
}
|| TREE_CODE (t) == SSA_NAME)
return;
- /* Any tree which is volatile disqualifies thie function from being
+ /* Any tree which is volatile disqualifies this function from being
const or pure. */
if (TREE_THIS_VOLATILE (t))
{
local->pure_const_state = IPA_NEITHER;
+ local->looping = false;
return;
}
if (checking_write)
{
local->pure_const_state = IPA_NEITHER;
+ local->looping = false;
return;
}
else if (local->pure_const_state == IPA_CONST)
actual asm statement. */
static void
-get_asm_expr_operands (funct_state local, tree stmt)
+get_asm_expr_operands (funct_state local, gimple stmt)
{
- int noutputs = list_length (ASM_OUTPUTS (stmt));
+ size_t noutputs = gimple_asm_noutputs (stmt);
const char **oconstraints
= (const char **) alloca ((noutputs) * sizeof (const char *));
- int i;
- tree link;
+ size_t i;
+ tree op;
const char *constraint;
bool allows_mem, allows_reg, is_inout;
- for (i=0, link = ASM_OUTPUTS (stmt); link; ++i, link = TREE_CHAIN (link))
+ for (i = 0; i < noutputs; i++)
{
+ op = gimple_asm_output_op (stmt, i);
oconstraints[i] = constraint
- = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
+ = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (op)));
parse_output_constraint (&constraint, i, 0, 0,
&allows_mem, &allows_reg, &is_inout);
- check_lhs_var (local, TREE_VALUE (link));
+ check_lhs_var (local, TREE_VALUE (op));
}
- for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
+ for (i = 0; i < gimple_asm_ninputs (stmt); i++)
{
+ op = gimple_asm_input_op (stmt, i);
constraint
- = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
+ = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (op)));
parse_input_constraint (&constraint, 0, 0, noutputs, 0,
oconstraints, &allows_mem, &allows_reg);
- check_rhs_var (local, TREE_VALUE (link));
+ check_rhs_var (local, TREE_VALUE (op));
}
- for (link = ASM_CLOBBERS (stmt); link; link = TREE_CHAIN (link))
- if (simple_cst_equal(TREE_VALUE (link), memory_identifier_string) == 1)
- /* Abandon all hope, ye who enter here. */
- local->pure_const_state = IPA_NEITHER;
+ for (i = 0; i < gimple_asm_nclobbers (stmt); i++)
+ {
+ op = gimple_asm_clobber_op (stmt, i);
+ if (simple_cst_equal(TREE_VALUE (op), memory_identifier_string) == 1)
+ /* Abandon all hope, ye who enter here. */
+ local->pure_const_state = IPA_NEITHER;
+ }
- if (ASM_VOLATILE_P (stmt))
+ if (gimple_asm_volatile_p (stmt))
local->pure_const_state = IPA_NEITHER;
}
the entire call expression. */
static void
-check_call (funct_state local, tree call_expr)
+check_call (funct_state local, gimple call)
{
- int flags = call_expr_flags (call_expr);
- tree operand;
- call_expr_arg_iterator iter;
- tree callee_t = get_callee_fndecl (call_expr);
+ int flags = gimple_call_flags (call);
+ tree lhs, callee_t = gimple_call_fndecl (call);
struct cgraph_node* callee;
enum availability avail = AVAIL_NOT_AVAILABLE;
+ size_t i;
- FOR_EACH_CALL_EXPR_ARG (operand, iter, call_expr)
- check_rhs_var (local, operand);
+ lhs = gimple_call_lhs (call);
+ if (lhs)
+ check_lhs_var (local, lhs);
+
+ for (i = 0; i < gimple_call_num_args (call); i++)
+ check_rhs_var (local, gimple_call_arg (call, i));
/* The const and pure flags are set by a variety of places in the
compiler (including here). If someone has already set the flags
/* When bad things happen to bad functions, they cannot be const
or pure. */
if (setjmp_call_p (callee_t))
- local->pure_const_state = IPA_NEITHER;
+ {
+ local->pure_const_state = IPA_NEITHER;
+ local->looping = false;
+ }
if (DECL_BUILT_IN_CLASS (callee_t) == BUILT_IN_NORMAL)
switch (DECL_FUNCTION_CODE (callee_t))
case BUILT_IN_LONGJMP:
case BUILT_IN_NONLOCAL_GOTO:
local->pure_const_state = IPA_NEITHER;
+ local->looping = false;
break;
default:
break;
should be converted to use the operand scanner. */
static tree
-scan_function (tree *tp,
- int *walk_subtrees,
- void *data)
+scan_function_op (tree *tp, int *walk_subtrees, void *data)
{
- struct cgraph_node *fn = (struct cgraph_node *) data;
+ struct walk_stmt_info *wi = (struct walk_stmt_info *) data;
+ struct cgraph_node *fn = (struct cgraph_node *) wi->info;
tree t = *tp;
funct_state local = get_function_state (fn);
{
case VAR_DECL:
if (DECL_INITIAL (t))
- walk_tree (&DECL_INITIAL (t), scan_function, fn, visited_nodes);
+ walk_tree (&DECL_INITIAL (t), scan_function_op, data, visited_nodes);
*walk_subtrees = 0;
break;
- case GIMPLE_MODIFY_STMT:
+ case ADDR_EXPR:
+ /* This case is here to find addresses on rhs of constructors in
+ decl_initial of static variables. */
+ check_rhs_var (local, t);
+ *walk_subtrees = 0;
+ break;
+
+ default:
+ break;
+ }
+ return NULL;
+}
+
+static tree
+scan_function_stmt (gimple_stmt_iterator *gsi_p,
+ bool *handled_ops_p,
+ struct walk_stmt_info *wi)
+{
+ struct cgraph_node *fn = (struct cgraph_node *) wi->info;
+ gimple stmt = gsi_stmt (*gsi_p);
+ funct_state local = get_function_state (fn);
+
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_ASSIGN:
{
/* First look on the lhs and see what variable is stored to */
- tree lhs = GIMPLE_STMT_OPERAND (t, 0);
- tree rhs = GIMPLE_STMT_OPERAND (t, 1);
+ tree lhs = gimple_assign_lhs (stmt);
+ tree rhs1 = gimple_assign_rhs1 (stmt);
+ tree rhs2 = gimple_assign_rhs2 (stmt);
+ enum tree_code code = gimple_assign_rhs_code (stmt);
+
check_lhs_var (local, lhs);
/* For the purposes of figuring out what the cast affects */
/* Next check the operands on the rhs to see if they are ok. */
- switch (TREE_CODE_CLASS (TREE_CODE (rhs)))
+ switch (TREE_CODE_CLASS (code))
{
case tcc_binary:
{
- tree op0 = TREE_OPERAND (rhs, 0);
- tree op1 = TREE_OPERAND (rhs, 1);
- check_rhs_var (local, op0);
- check_rhs_var (local, op1);
+ check_rhs_var (local, rhs1);
+ check_rhs_var (local, rhs2);
}
break;
case tcc_unary:
{
- tree op0 = TREE_OPERAND (rhs, 0);
- check_rhs_var (local, op0);
+ check_rhs_var (local, rhs1);
}
break;
case tcc_reference:
- check_rhs_var (local, rhs);
+ check_rhs_var (local, rhs1);
break;
case tcc_declaration:
- check_rhs_var (local, rhs);
+ check_rhs_var (local, rhs1);
break;
case tcc_expression:
- switch (TREE_CODE (rhs))
+ switch (code)
{
case ADDR_EXPR:
- check_rhs_var (local, rhs);
- break;
- default:
- break;
- }
- break;
- case tcc_vl_exp:
- switch (TREE_CODE (rhs))
- {
- case CALL_EXPR:
- check_call (local, rhs);
+ check_rhs_var (local, rhs1);
break;
default:
break;
default:
break;
}
- *walk_subtrees = 0;
+ *handled_ops_p = true;
}
break;
- case ADDR_EXPR:
- /* This case is here to find addresses on rhs of constructors in
- decl_initial of static variables. */
- check_rhs_var (local, t);
- *walk_subtrees = 0;
- break;
-
- case LABEL_EXPR:
- if (DECL_NONLOCAL (TREE_OPERAND (t, 0)))
+ case GIMPLE_LABEL:
+ if (DECL_NONLOCAL (gimple_label_label (stmt)))
/* Target of long jump. */
- local->pure_const_state = IPA_NEITHER;
+ {
+ local->pure_const_state = IPA_NEITHER;
+ local->looping = false;
+ }
break;
- case CALL_EXPR:
- check_call (local, t);
- *walk_subtrees = 0;
+ case GIMPLE_CALL:
+ check_call (local, stmt);
+ *handled_ops_p = true;
break;
- case ASM_EXPR:
- get_asm_expr_operands (local, t);
- *walk_subtrees = 0;
+ case GIMPLE_ASM:
+ get_asm_expr_operands (local, stmt);
+ *handled_ops_p = true;
break;
default:
return NULL;
}
+
/* This is the main routine for finding the reference patterns for
global variables within a function FN. */
static void
analyze_function (struct cgraph_node *fn)
{
- funct_state l = XCNEW (struct funct_state_d);
tree decl = fn->decl;
- struct ipa_dfs_info * w_info = (struct ipa_dfs_info *) fn->aux;
+ funct_state l = XCNEW (struct funct_state_d);
+
+ if (cgraph_function_body_availability (fn) <= AVAIL_OVERWRITABLE)
+ return;
- w_info->aux = l;
+ set_function_state (fn, l);
l->pure_const_state = IPA_CONST;
l->state_set_in_source = false;
+ if (DECL_LOOPING_CONST_OR_PURE_P (decl))
+ l->looping = true;
+ else
+ l->looping = false;
/* If this function does not return normally or does not bind local,
do not touch this unless it has been marked as const or pure by the
l->pure_const_state = IPA_CONST;
l->state_set_in_source = true;
}
- if (DECL_IS_PURE (decl))
+ if (DECL_PURE_P (decl))
{
l->pure_const_state = IPA_PURE;
l->state_set_in_source = true;
FOR_EACH_BB_FN (this_block, this_cfun)
{
- block_stmt_iterator bsi;
- for (bsi = bsi_start (this_block); !bsi_end_p (bsi); bsi_next (&bsi))
+ gimple_stmt_iterator gsi;
+ struct walk_stmt_info wi;
+
+ memset (&wi, 0, sizeof(wi));
+ for (gsi = gsi_start_bb (this_block);
+ !gsi_end_p (gsi);
+ gsi_next (&gsi))
{
- walk_tree (bsi_stmt_ptr (bsi), scan_function,
- fn, visited_nodes);
+ wi.info = fn;
+ wi.pset = visited_nodes;
+ walk_gimple_stmt (&gsi, scan_function_stmt, scan_function_op,
+ &wi);
if (l->pure_const_state == IPA_NEITHER)
goto end;
}
}
}
+/* Called when new function is inserted to callgraph late. */
+static void
+add_new_function (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
+{
+ 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
+ since all we would be interested in are the addressof
+ operations. */
+ visited_nodes = pointer_set_create ();
+ analyze_function (node);
+ pointer_set_destroy (visited_nodes);
+ visited_nodes = NULL;
+}
+
+/* Called when new clone is inserted to callgraph late. */
+
+static void
+duplicate_node_data (struct cgraph_node *src, struct cgraph_node *dst,
+ void *data ATTRIBUTE_UNUSED)
+{
+ if (get_function_state (src))
+ {
+ funct_state l = XNEW (struct funct_state_d);
+ gcc_assert (!get_function_state (dst));
+ memcpy (l, get_function_state (src), sizeof (*l));
+ set_function_state (dst, l);
+ }
+}
+
+/* Called when new clone is inserted to callgraph late. */
+
+static void
+remove_node_data (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
+{
+ if (get_function_state (node))
+ {
+ free (get_function_state (node));
+ set_function_state (node, NULL);
+ }
+}
+
\f
-/* Produce the global information by preforming a transitive closure
- on the local information that was produced by ipa_analyze_function
- and ipa_analyze_variable. */
+/* Analyze each function in the cgraph to see if it is locally PURE or
+ CONST. */
-static unsigned int
-static_execute (void)
+static void
+generate_summary (void)
{
struct cgraph_node *node;
- struct cgraph_node *w;
- struct cgraph_node **order =
- XCNEWVEC (struct cgraph_node *, cgraph_n_nodes);
- int order_pos = ipa_utils_reduced_inorder (order, true, false);
- int i;
- struct ipa_dfs_info * w_info;
-
- if (!memory_identifier_string)
- memory_identifier_string = build_string(7, "memory");
+ node_removal_hook_holder =
+ cgraph_add_node_removal_hook (&remove_node_data, NULL);
+ node_duplication_hook_holder =
+ cgraph_add_node_duplication_hook (&duplicate_node_data, NULL);
+ function_insertion_hook_holder =
+ cgraph_add_function_insertion_hook (&add_new_function, NULL);
/* 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 want to process any of the clones so we check that this
- is a master clone. However, we do NOT process any
- AVAIL_OVERWRITABLE functions (these are never clones) we cannot
+ 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 overriders it.
+ for the one that overrides it.
*/
for (node = cgraph_nodes; node; node = node->next)
- if (node->analyzed && cgraph_is_master_clone (node))
+ if (cgraph_function_body_availability (node) > AVAIL_OVERWRITABLE)
analyze_function (node);
pointer_set_destroy (visited_nodes);
visited_nodes = NULL;
+}
+
+/* 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
+ updates the function_decl. */
+
+static unsigned int
+propagate (void)
+{
+ struct cgraph_node *node;
+ struct cgraph_node *w;
+ struct cgraph_node **order =
+ XCNEWVEC (struct cgraph_node *, cgraph_n_nodes);
+ int order_pos;
+ int i;
+ struct ipa_dfs_info * w_info;
+
+ 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);
if (dump_file)
{
dump_cgraph (dump_file);
for (i = 0; i < order_pos; i++ )
{
enum pure_const_state_e pure_const_state = IPA_CONST;
+ bool looping = 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->looping)
+ looping = true;
+
if (pure_const_state == IPA_NEITHER)
break;
struct cgraph_edge *e;
count++;
- /* FIXME!!! Because of pr33826, we cannot have either
- immediate or transitive recursive functions marked as
- pure or const because dce can delete a function that
- is in reality an infinite loop. A better solution
- than just outlawing them is to add another bit the
- functions to distinguish recursive from non recursive
- pure and const function. This would allow the
- recursive ones to be cse'd but not dce'd. In this
- same vein, we could allow functions with loops to
- also be cse'd but not dce'd.
-
- Unfortunately we are late in stage 3, and the fix
- described above is is not appropriate. */
if (count > 1)
- {
- pure_const_state = IPA_NEITHER;
- break;
- }
+ looping = true;
for (e = w->callees; e; e = e->next_callee)
{
struct cgraph_node *y = e->callee;
- /* Only look at the master nodes and skip external nodes. */
- y = cgraph_master_clone (y);
- /* Check for immediate recursive functions. See the
- FIXME above. */
- if (w == y)
- {
- pure_const_state = IPA_NEITHER;
- break;
- }
- if (y)
+ if (cgraph_function_body_availability (y) > AVAIL_OVERWRITABLE)
{
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)
break;
+ if (y_l->looping)
+ looping = true;
}
}
}
if (!w_l->state_set_in_source)
{
w_l->pure_const_state = pure_const_state;
+ w_l->looping = looping;
+
switch (pure_const_state)
{
case IPA_CONST:
TREE_READONLY (w->decl) = 1;
+ DECL_LOOPING_CONST_OR_PURE_P (w->decl) = looping;
if (dump_file)
- fprintf (dump_file, "Function found to be const: %s\n",
+ fprintf (dump_file, "Function found to be %sconst: %s\n",
+ looping ? "looping " : "",
lang_hooks.decl_printable_name(w->decl, 2));
break;
case IPA_PURE:
- DECL_IS_PURE (w->decl) = 1;
+ DECL_PURE_P (w->decl) = 1;
+ DECL_LOOPING_CONST_OR_PURE_P (w->decl) = looping;
if (dump_file)
- fprintf (dump_file, "Function found to be pure: %s\n",
+ fprintf (dump_file, "Function found to be %spure: %s\n",
+ looping ? "looping " : "",
lang_hooks.decl_printable_name(w->decl, 2));
break;
/* 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;
- if (w_info->aux)
- free (w_info->aux);
- free (node->aux);
- node->aux = NULL;
- }
-
+ {
+ /* Get rid of the aux information. */
+ if (node->aux)
+ {
+ w_info = (struct ipa_dfs_info *) node->aux;
+ free (node->aux);
+ node->aux = NULL;
+ }
+ if (cgraph_function_body_availability (node) > AVAIL_OVERWRITABLE)
+ free (get_function_state (node));
+ }
+
free (order);
+ VEC_free (funct_state, heap, funct_state_vec);
+ finish_state ();
return 0;
}
static bool
gate_pure_const (void)
{
- return (flag_unit_at_a_time != 0 && flag_ipa_pure_const
+ return (flag_ipa_pure_const
/* Don't bother doing anything if the program has errors. */
&& !(errorcount || sorrycount));
}
-struct simple_ipa_opt_pass pass_ipa_pure_const =
+struct ipa_opt_pass pass_ipa_pure_const =
{
{
- SIMPLE_IPA_PASS,
+ IPA_PASS,
"pure-const", /* name */
gate_pure_const, /* gate */
- static_execute, /* execute */
+ propagate, /* execute */
NULL, /* sub */
NULL, /* next */
0, /* static_pass_number */
0, /* properties_destroyed */
0, /* todo_flags_start */
0 /* todo_flags_finish */
- }
+ },
+ generate_summary, /* generate_summary */
+ NULL, /* write_summary */
+ NULL, /* read_summary */
+ NULL, /* function_read_summary */
+ 0, /* TODOs */
+ NULL, /* function_transform */
+ NULL /* variable_transform */
};
-
-
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