/* 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 "tree-gimple.h"
+#include "gimple.h"
#include "cgraph.h"
#include "output.h"
#include "flags.h"
#include "diagnostic.h"
#include "langhooks.h"
#include "target.h"
+#include "cfgloop.h"
+#include "tree-scalar-evolution.h"
static struct pointer_set_t *visited_nodes;
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;
+ /* What user set here; we can be always sure about this. */
+ 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
+ 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;
- bool state_set_in_source;
+
+ bool can_throw;
};
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 CHECKING_WRITE is true)
check_decl (funct_state local,
tree t, bool checking_write)
{
- /* If the variable has the "used" attribute, treat it as if it had a
- been touched by the devil. */
- if (lookup_attribute ("used", DECL_ATTRIBUTES (t)))
- {
- local->pure_const_state = IPA_NEITHER;
- local->looping = false;
- return;
- }
-
/* Do not want to do anything with volatile except mark any
function that uses one to be not const or pure. */
if (TREE_THIS_VOLATILE (t))
{
local->pure_const_state = IPA_NEITHER;
- local->looping = false;
+ if (dump_file)
+ fprintf (dump_file, " Volatile operand is not const/pure");
return;
}
if (!TREE_STATIC (t) && !DECL_EXTERNAL (t))
return;
+ /* If the variable has the "used" attribute, treat it as if it had a
+ been touched by the devil. */
+ if (lookup_attribute ("used", DECL_ATTRIBUTES (t)))
+ {
+ local->pure_const_state = IPA_NEITHER;
+ if (dump_file)
+ fprintf (dump_file, " Used static/global variable is not const/pure\n");
+ return;
+ }
+
/* Since we have dealt with the locals and params cases above, if we
are CHECKING_WRITE, this cannot be a pure or constant
function. */
if (checking_write)
{
local->pure_const_state = IPA_NEITHER;
- local->looping = false;
+ if (dump_file)
+ fprintf (dump_file, " static/global memory write is not const/pure\n");
return;
}
if (DECL_EXTERNAL (t) || TREE_PUBLIC (t))
{
- /* If the front end set the variable to be READONLY and
- constant, we can allow this variable in pure or const
- functions but the scope is too large for our analysis to set
- these bits ourselves. */
-
- if (TREE_READONLY (t)
- && DECL_INITIAL (t)
- && is_gimple_min_invariant (DECL_INITIAL (t)))
- ; /* Read of a constant, do not change the function state. */
+ /* Readonly reads are safe. */
+ if (TREE_READONLY (t) && !TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (t)))
+ return; /* Read of a constant, do not change the function state. */
else
{
+ if (dump_file)
+ fprintf (dump_file, " global memory read is not const\n");
/* Just a regular read. */
if (local->pure_const_state == IPA_CONST)
local->pure_const_state = IPA_PURE;
}
}
-
- /* Compilation level statics can be read if they are readonly
- variables. */
- if (TREE_READONLY (t))
- return;
-
- /* Just a regular read. */
- if (local->pure_const_state == IPA_CONST)
- local->pure_const_state = IPA_PURE;
+ else
+ {
+ /* Compilation level statics can be read if they are readonly
+ variables. */
+ if (TREE_READONLY (t))
+ return;
+
+ if (dump_file)
+ fprintf (dump_file, " static memory read is not const\n");
+ /* Just a regular read. */
+ if (local->pure_const_state == IPA_CONST)
+ local->pure_const_state = IPA_PURE;
+ }
}
-/* If T is a VAR_DECL check to see if it is an allowed reference. */
-static void
-check_operand (funct_state local,
- tree t, bool checking_write)
-{
- if (!t) return;
-
- if (TREE_CODE (t) == VAR_DECL)
- check_decl (local, t, checking_write);
-}
-
-/* Examine tree T for references. */
+/* 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 void
-check_tree (funct_state local, tree t, bool checking_write)
+static inline void
+check_op (funct_state local, tree t, bool checking_write)
{
- if ((TREE_CODE (t) == EXC_PTR_EXPR) || (TREE_CODE (t) == FILTER_EXPR)
- || TREE_CODE (t) == SSA_NAME)
- return;
-
- /* Any tree which is volatile disqualifies this function from being
- const or pure. */
- if (TREE_THIS_VOLATILE (t))
+ t = get_base_address (t);
+ if (t && TREE_THIS_VOLATILE (t))
{
local->pure_const_state = IPA_NEITHER;
- local->looping = false;
+ if (dump_file)
+ fprintf (dump_file, " Volatile indirect ref is not const/pure\n");
return;
}
-
- while (TREE_CODE (t) == REALPART_EXPR
- || TREE_CODE (t) == IMAGPART_EXPR
- || handled_component_p (t))
- {
- if (TREE_CODE (t) == ARRAY_REF)
- check_operand (local, TREE_OPERAND (t, 1), false);
- t = TREE_OPERAND (t, 0);
- }
-
- /* The bottom of an indirect reference can only be read, not
- written. */
- if (INDIRECT_REF_P (t))
+ 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)))
{
- check_tree (local, TREE_OPERAND (t, 0), false);
-
- /* Any indirect reference that occurs on the lhs
- disqualifies the function from being pure or const. Any
- indirect reference that occurs on the rhs disqualifies the
- function from being const. */
- if (checking_write)
- {
- local->pure_const_state = IPA_NEITHER;
- local->looping = false;
- return;
- }
- else if (local->pure_const_state == IPA_CONST)
- local->pure_const_state = IPA_PURE;
- }
-
- if (SSA_VAR_P (t))
- check_operand (local, t, checking_write);
-}
-
-/* Scan tree T to see if there are any addresses taken in within T. */
-
-static void
-look_for_address_of (funct_state local, tree t)
-{
- if (TREE_CODE (t) == ADDR_EXPR)
- {
- tree x = get_base_var (t);
- if (TREE_CODE (x) == VAR_DECL)
- {
- check_decl (local, x, false);
-
- /* Taking the address of something appears to be reasonable
- in PURE code. Not allowed in const. */
- if (local->pure_const_state == IPA_CONST)
- local->pure_const_state = IPA_PURE;
- }
+ if (dump_file)
+ fprintf (dump_file, " Indirect ref to local memory is OK\n");
+ return;
}
-}
-
-/* Check to see if T is a read or address of operation on a var we are
- interested in analyzing. LOCAL is passed in to get access to its
- bit vectors. */
-
-static void
-check_rhs_var (funct_state local, tree t)
-{
- look_for_address_of (local, t);
-
- /* Memcmp and strlen can both trap and they are declared pure. */
- if (tree_could_trap_p (t)
- && local->pure_const_state == IPA_CONST)
- local->pure_const_state = IPA_PURE;
-
- check_tree(local, t, false);
-}
-
-/* Check to see if T is an assignment to a var we are interested in
- analyzing. LOCAL is passed in to get access to its bit vectors. */
-
-static void
-check_lhs_var (funct_state local, tree t)
-{
- /* Memcmp and strlen can both trap and they are declared pure.
- Which seems to imply that we can apply the same rule here. */
- if (tree_could_trap_p (t)
- && local->pure_const_state == IPA_CONST)
- local->pure_const_state = IPA_PURE;
-
- check_tree(local, t, true);
-}
-
-/* This is a scaled down version of get_asm_expr_operands from
- tree_ssa_operands.c. The version there runs much later and assumes
- that aliasing information is already available. Here we are just
- trying to find if the set of inputs and outputs contain references
- or address of operations to local static variables. STMT is the
- actual asm statement. */
-
-static void
-get_asm_expr_operands (funct_state local, tree stmt)
-{
- int noutputs = list_length (ASM_OUTPUTS (stmt));
- const char **oconstraints
- = (const char **) alloca ((noutputs) * sizeof (const char *));
- int i;
- tree link;
- const char *constraint;
- bool allows_mem, allows_reg, is_inout;
-
- for (i=0, link = ASM_OUTPUTS (stmt); link; ++i, link = TREE_CHAIN (link))
+ else if (checking_write)
{
- oconstraints[i] = constraint
- = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
- parse_output_constraint (&constraint, i, 0, 0,
- &allows_mem, &allows_reg, &is_inout);
-
- check_lhs_var (local, TREE_VALUE (link));
+ local->pure_const_state = IPA_NEITHER;
+ if (dump_file)
+ fprintf (dump_file, " Indirect ref write is not const/pure\n");
+ return;
}
-
- for (link = ASM_INPUTS (stmt); link; link = TREE_CHAIN (link))
+ else
{
- constraint
- = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (link)));
- parse_input_constraint (&constraint, 0, 0, noutputs, 0,
- oconstraints, &allows_mem, &allows_reg);
-
- check_rhs_var (local, TREE_VALUE (link));
+ if (dump_file)
+ fprintf (dump_file, " Indirect ref read is not const\n");
+ if (local->pure_const_state == IPA_CONST)
+ local->pure_const_state = IPA_PURE;
}
-
- 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;
-
- if (ASM_VOLATILE_P (stmt))
- local->pure_const_state = IPA_NEITHER;
}
/* Check the parameters of a function call to CALL_EXPR to see if
the entire call expression. */
static void
-check_call (funct_state local, tree call_expr)
+check_call (funct_state local, gimple call, bool ipa)
{
- 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 callee_t = gimple_call_fndecl (call);
struct cgraph_node* callee;
enum availability avail = AVAIL_NOT_AVAILABLE;
+ bool possibly_throws = stmt_could_throw_p (call);
+ bool possibly_throws_externally = (possibly_throws
+ && stmt_can_throw_external (call));
- FOR_EACH_CALL_EXPR_ARG (operand, iter, call_expr)
- check_rhs_var (local, operand);
+ if (possibly_throws)
+ {
+ unsigned int i;
+ for (i = 0; i < gimple_num_ops (call); i++)
+ if (gimple_op (call, i)
+ && tree_could_throw_p (gimple_op (call, i)))
+ {
+ if (possibly_throws && flag_non_call_exceptions)
+ {
+ if (dump_file)
+ fprintf (dump_file, " operand can throw; looping\n");
+ local->looping = true;
+ }
+ if (possibly_throws_externally)
+ {
+ if (dump_file)
+ fprintf (dump_file, " operand can throw externally\n");
+ local->can_throw = true;
+ }
+ }
+ }
/* The const and pure flags are set by a variety of places in the
compiler (including here). If someone has already set the flags
or pure. */
if (setjmp_call_p (callee_t))
{
+ if (dump_file)
+ fprintf (dump_file, " setjmp is not const/pure\n");
+ local->looping = true;
local->pure_const_state = IPA_NEITHER;
- local->looping = false;
}
if (DECL_BUILT_IN_CLASS (callee_t) == BUILT_IN_NORMAL)
{
case BUILT_IN_LONGJMP:
case BUILT_IN_NONLOCAL_GOTO:
+ if (dump_file)
+ fprintf (dump_file, " longjmp and nonlocal goto is not const/pure\n");
local->pure_const_state = IPA_NEITHER;
- local->looping = false;
+ local->looping = true;
break;
default:
break;
}
}
+ /* 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. */
- if (avail == AVAIL_NOT_AVAILABLE || avail == AVAIL_OVERWRITABLE)
+ else if (avail <= AVAIL_OVERWRITABLE || !ipa)
{
- if (flags & ECF_PURE)
+ if (possibly_throws && flag_non_call_exceptions)
+ {
+ if (dump_file)
+ fprintf (dump_file, " can throw; looping\n");
+ local->looping = true;
+ }
+ if (possibly_throws_externally)
+ {
+ if (dump_file)
+ {
+ 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)));
+ }
+ local->can_throw = true;
+ }
+ if (flags & ECF_CONST)
+ {
+ if (callee_t && DECL_LOOPING_CONST_OR_PURE_P (callee_t))
+ local->looping = true;
+ }
+ else if (flags & ECF_PURE)
{
+ if (callee_t && DECL_LOOPING_CONST_OR_PURE_P (callee_t))
+ local->looping = true;
+ if (dump_file)
+ fprintf (dump_file, " pure function call in not const\n");
if (local->pure_const_state == IPA_CONST)
local->pure_const_state = IPA_PURE;
}
else
- local->pure_const_state = IPA_NEITHER;
- }
- else
- {
- /* We have the code and we will scan it for the effects. */
- if (flags & ECF_PURE)
{
- if (local->pure_const_state == IPA_CONST)
- local->pure_const_state = IPA_PURE;
+ if (dump_file)
+ fprintf (dump_file, " uknown function call is not const/pure\n");
+ local->pure_const_state = IPA_NEITHER;
+ local->looping = true;
}
}
+ /* Direct functions calls are handled by IPA propagation. */
}
-/* TP is the part of the tree currently under the microscope.
- WALK_SUBTREES is part of the walk_tree api but is unused here.
- DATA is cgraph_node of the function being walked. */
+/* Wrapper around check_decl for loads. */
-/* FIXME: When this is converted to run over SSA form, this code
- should be converted to use the operand scanner. */
-
-static tree
-scan_function (tree *tp,
- int *walk_subtrees,
- void *data)
+static bool
+check_load (gimple stmt ATTRIBUTE_UNUSED, tree op, void *data)
{
- struct cgraph_node *fn = (struct cgraph_node *) data;
- tree t = *tp;
- funct_state local = get_function_state (fn);
+ if (DECL_P (op))
+ check_decl ((funct_state)data, op, false);
+ else
+ check_op ((funct_state)data, op, false);
+ return false;
+}
- switch (TREE_CODE (t))
- {
- case VAR_DECL:
- if (DECL_INITIAL (t))
- walk_tree (&DECL_INITIAL (t), scan_function, fn, visited_nodes);
- *walk_subtrees = 0;
- break;
+/* Wrapper around check_decl for stores. */
- case GIMPLE_MODIFY_STMT:
- {
- /* 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);
- check_lhs_var (local, lhs);
+static bool
+check_store (gimple stmt ATTRIBUTE_UNUSED, tree op, void *data)
+{
+ if (DECL_P (op))
+ check_decl ((funct_state)data, op, true);
+ else
+ check_op ((funct_state)data, op, true);
+ return false;
+}
- /* For the purposes of figuring out what the cast affects */
+/* Look into pointer pointed to by GSIP and figure out what interesting side
+ effects it has. */
+static void
+check_stmt (gimple_stmt_iterator *gsip, funct_state local, bool ipa)
+{
+ gimple stmt = gsi_stmt (*gsip);
+ unsigned int i = 0;
- /* Next check the operands on the rhs to see if they are ok. */
- switch (TREE_CODE_CLASS (TREE_CODE (rhs)))
- {
- 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);
- }
- break;
- case tcc_unary:
- {
- tree op0 = TREE_OPERAND (rhs, 0);
- check_rhs_var (local, op0);
- }
+ if (is_gimple_debug (stmt))
+ return;
- break;
- case tcc_reference:
- check_rhs_var (local, rhs);
- break;
- case tcc_declaration:
- check_rhs_var (local, rhs);
- break;
- case tcc_expression:
- switch (TREE_CODE (rhs))
- {
- 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);
- break;
- default:
- break;
- }
- break;
- default:
- break;
- }
- *walk_subtrees = 0;
- }
- break;
+ if (dump_file)
+ {
+ fprintf (dump_file, " scanning: ");
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ }
- 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;
+ /* Look for loads and stores. */
+ walk_stmt_load_store_ops (stmt, local, check_load, check_store);
- case LABEL_EXPR:
- if (DECL_NONLOCAL (TREE_OPERAND (t, 0)))
+ if (gimple_code (stmt) != GIMPLE_CALL
+ && stmt_could_throw_p (stmt))
+ {
+ if (flag_non_call_exceptions)
+ {
+ if (dump_file)
+ fprintf (dump_file, " can throw; looping");
+ local->looping = true;
+ }
+ if (stmt_can_throw_external (stmt))
+ {
+ if (dump_file)
+ fprintf (dump_file, " can throw externally");
+ local->can_throw = true;
+ }
+ }
+ switch (gimple_code (stmt))
+ {
+ case GIMPLE_CALL:
+ check_call (local, stmt, ipa);
+ break;
+ case GIMPLE_LABEL:
+ if (DECL_NONLOCAL (gimple_label_label (stmt)))
/* Target of long jump. */
{
+ if (dump_file)
+ fprintf (dump_file, " nonlocal label is not const/pure");
local->pure_const_state = IPA_NEITHER;
- local->looping = false;
}
break;
-
- case CALL_EXPR:
- check_call (local, t);
- *walk_subtrees = 0;
- break;
-
- case ASM_EXPR:
- get_asm_expr_operands (local, t);
- *walk_subtrees = 0;
- break;
-
+ case GIMPLE_ASM:
+ for (i = 0; i < gimple_asm_nclobbers (stmt); i++)
+ {
+ tree op = gimple_asm_clobber_op (stmt, i);
+ if (simple_cst_equal(TREE_VALUE (op), memory_identifier_string) == 1)
+ {
+ if (dump_file)
+ fprintf (dump_file, " memory asm clobber is not const/pure");
+ /* Abandon all hope, ye who enter here. */
+ local->pure_const_state = IPA_NEITHER;
+ }
+ }
+ if (gimple_asm_volatile_p (stmt))
+ {
+ if (dump_file)
+ fprintf (dump_file, " volatile is not const/pure");
+ /* Abandon all hope, ye who enter here. */
+ local->pure_const_state = IPA_NEITHER;
+ local->looping = true;
+ }
+ return;
default:
break;
}
- 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)
+static funct_state
+analyze_function (struct cgraph_node *fn, bool ipa)
{
- funct_state l = XCNEW (struct funct_state_d);
tree decl = fn->decl;
- struct ipa_dfs_info * w_info = (struct ipa_dfs_info *) fn->aux;
+ tree old_decl = current_function_decl;
+ funct_state l;
+ basic_block this_block;
- w_info->aux = l;
+ 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 = false;
- if (DECL_LOOPING_CONST_OR_PURE_P (decl))
- l->looping = true;
- else
- l->looping = false;
+ l->state_previously_known = IPA_NEITHER;
+ l->looping_previously_known = true;
+ l->looping = false;
+ l->can_throw = 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
- front end. */
- if (TREE_THIS_VOLATILE (decl)
- || !targetm.binds_local_p (decl))
+ if (dump_file)
{
- l->pure_const_state = IPA_NEITHER;
- return;
+ fprintf (dump_file, "\n\n local analysis of %s\n ",
+ cgraph_node_name (fn));
+ }
+
+ push_cfun (DECL_STRUCT_FUNCTION (decl));
+ current_function_decl = decl;
+
+ FOR_EACH_BB (this_block)
+ {
+ 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))
+ {
+ check_stmt (&gsi, l, ipa);
+ if (l->pure_const_state == IPA_NEITHER && l->looping && l->can_throw)
+ goto end;
+ }
+ }
+
+end:
+ if (l->pure_const_state != IPA_NEITHER)
+ {
+ /* Const functions cannot have back edges (an
+ indication of possible infinite loop side
+ effect. */
+ if (mark_dfs_back_edges ())
+ {
+ /* 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 = true;
+ l->state_previously_known = IPA_CONST;
+ if (!DECL_LOOPING_CONST_OR_PURE_P (decl))
+ l->looping = false, l->looping_previously_known = false;
}
if (DECL_PURE_P (decl))
{
- l->pure_const_state = IPA_PURE;
- l->state_set_in_source = true;
+ if (l->pure_const_state != IPA_CONST)
+ l->pure_const_state = IPA_PURE;
+ l->state_previously_known = IPA_PURE;
+ if (!DECL_LOOPING_CONST_OR_PURE_P (decl))
+ l->looping = false, l->looping_previously_known = false;
}
+ if (TREE_NOTHROW (decl))
+ l->can_throw = false;
+ pop_cfun ();
+ current_function_decl = old_decl;
if (dump_file)
{
- fprintf (dump_file, "\n local analysis of %s with initial value = %d\n ",
- cgraph_node_name (fn),
- l->pure_const_state);
+ if (l->looping)
+ fprintf (dump_file, "Function is locally looping.\n");
+ if (l->can_throw)
+ fprintf (dump_file, "Function is locally throwing.\n");
+ if (l->pure_const_state == IPA_CONST)
+ fprintf (dump_file, "Function is locally const.\n");
+ if (l->pure_const_state == IPA_PURE)
+ fprintf (dump_file, "Function is locally pure.\n");
}
-
- if (!l->state_set_in_source)
- {
- struct function *this_cfun = DECL_STRUCT_FUNCTION (decl);
- basic_block this_block;
-
- 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))
- {
- walk_tree (bsi_stmt_ptr (bsi), scan_function,
- fn, visited_nodes);
- if (l->pure_const_state == IPA_NEITHER)
- goto end;
- }
- }
+ return l;
+}
- if (l->pure_const_state != IPA_NEITHER)
- {
- tree old_decl = current_function_decl;
- /* Const functions cannot have back edges (an
- indication of possible infinite loop side
- effect. */
-
- current_function_decl = fn->decl;
-
- /* The C++ front end, has a tendency to some times jerk away
- a function after it has created it. This should have
- been fixed. */
- gcc_assert (DECL_STRUCT_FUNCTION (fn->decl));
-
- push_cfun (DECL_STRUCT_FUNCTION (fn->decl));
-
- if (mark_dfs_back_edges ())
- l->pure_const_state = IPA_NEITHER;
-
- current_function_decl = old_decl;
- pop_cfun ();
- }
+/* 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 ();
+ set_function_state (node, analyze_function (node, true));
+ 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);
}
+}
-end:
- if (dump_file)
+/* 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))
{
- fprintf (dump_file, "after local analysis of %s with initial value = %d\n ",
- cgraph_node_name (fn),
- l->pure_const_state);
+ 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 overrides it.
*/
for (node = cgraph_nodes; node; node = node->next)
- if (node->analyzed && cgraph_is_master_clone (node))
- analyze_function (node);
+ if (cgraph_function_body_availability (node) > AVAIL_OVERWRITABLE)
+ set_function_state (node, analyze_function (node, true));
pointer_set_destroy (visited_nodes);
visited_nodes = NULL;
+}
+
+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
+ 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, NULL);
if (dump_file)
{
dump_cgraph (dump_file);
w = node;
while (w)
{
+ struct cgraph_edge *e;
funct_state w_l = get_function_state (w);
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)
+ if (pure_const_state == IPA_NEITHER)
break;
- if (!w_l->state_set_in_source)
+ count++;
+
+ if (count > 1)
+ looping = true;
+
+ for (e = w->callees; e; e = e->next_callee)
{
- struct cgraph_edge *e;
- count++;
+ struct cgraph_node *y = e->callee;
- if (count > 1)
- looping = true;
-
- for (e = w->callees; e; e = e->next_callee)
+ if (cgraph_function_body_availability (y) > AVAIL_OVERWRITABLE)
{
- struct cgraph_node *y = e->callee;
- /* Only look at the master nodes and skip external nodes. */
- y = cgraph_master_clone (y);
-
- if (w == y)
+ 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 (y)
- {
- 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;
- }
}
}
w_info = (struct ipa_dfs_info *) w->aux;
while (w)
{
funct_state w_l = get_function_state (w);
+ enum pure_const_state_e this_state = pure_const_state;
+ bool this_looping = looping;
+
+ 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. */
- if (!w_l->state_set_in_source)
+ w_l->pure_const_state = this_state;
+ w_l->looping = this_looping;
+
+ switch (this_state)
{
- w_l->pure_const_state = pure_const_state;
- switch (pure_const_state)
+ case IPA_CONST:
+ if (!TREE_READONLY (w->decl) && dump_file)
+ fprintf (dump_file, "Function found to be %sconst: %s\n",
+ this_looping ? "looping " : "",
+ cgraph_node_name (w));
+ TREE_READONLY (w->decl) = 1;
+ DECL_LOOPING_CONST_OR_PURE_P (w->decl) = this_looping;
+ break;
+
+ case IPA_PURE:
+ if (!DECL_PURE_P (w->decl) && dump_file)
+ fprintf (dump_file, "Function found to be %spure: %s\n",
+ this_looping ? "looping " : "",
+ cgraph_node_name (w));
+ DECL_PURE_P (w->decl) = 1;
+ DECL_LOOPING_CONST_OR_PURE_P (w->decl) = this_looping;
+ break;
+
+ 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)
+ 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)
{
- 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 %sconst: %s\n",
- looping ? "looping " : "",
- lang_hooks.decl_printable_name(w->decl, 2));
- break;
-
- case IPA_PURE:
- 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 %spure: %s\n",
- looping ? "looping " : "",
- lang_hooks.decl_printable_name(w->decl, 2));
- break;
-
- default:
- break;
+ 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;
}
}
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))
+ {
+ 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;
+ }
}
/* 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_d 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 */
};
+/* Simple local pass for pure const discovery reusing the analysis from
+ ipa_pure_const. This pass is effective when executed together with
+ other optimization passes in early optimization pass queue. */
+static unsigned int
+local_pure_const (void)
+{
+ bool changed = false;
+ funct_state l;
+
+ /* Because we do not schedule pass_fixup_cfg over whole program after early optimizations
+ we must not promote functions that are called by already processed functions. */
+
+ if (function_called_by_processed_nodes_p ())
+ {
+ if (dump_file)
+ fprintf (dump_file, "Function called in recursive cycle; ignoring\n");
+ return 0;
+ }
+
+ l = analyze_function (cgraph_node (current_function_decl), false);
+ if (!l)
+ {
+ if (dump_file)
+ fprintf (dump_file, "Function has wrong visibility; ignoring\n");
+ return 0;
+ }
+
+ switch (l->pure_const_state)
+ {
+ case IPA_CONST:
+ if (!TREE_READONLY (current_function_decl))
+ {
+ TREE_READONLY (current_function_decl) = 1;
+ DECL_LOOPING_CONST_OR_PURE_P (current_function_decl) = l->looping;
+ changed = true;
+ if (dump_file)
+ fprintf (dump_file, "Function found to be %sconst: %s\n",
+ l->looping ? "looping " : "",
+ lang_hooks.decl_printable_name (current_function_decl,
+ 2));
+ }
+ else if (DECL_LOOPING_CONST_OR_PURE_P (current_function_decl)
+ && !l->looping)
+ {
+ DECL_LOOPING_CONST_OR_PURE_P (current_function_decl) = false;
+ changed = true;
+ if (dump_file)
+ fprintf (dump_file, "Function found to be non-looping: %s\n",
+ lang_hooks.decl_printable_name (current_function_decl,
+ 2));
+ }
+ break;
+
+ case IPA_PURE:
+ if (!TREE_READONLY (current_function_decl))
+ {
+ DECL_PURE_P (current_function_decl) = 1;
+ DECL_LOOPING_CONST_OR_PURE_P (current_function_decl) = l->looping;
+ changed = true;
+ if (dump_file)
+ fprintf (dump_file, "Function found to be %spure: %s\n",
+ l->looping ? "looping " : "",
+ lang_hooks.decl_printable_name (current_function_decl,
+ 2));
+ }
+ else if (DECL_LOOPING_CONST_OR_PURE_P (current_function_decl)
+ && !l->looping)
+ {
+ DECL_LOOPING_CONST_OR_PURE_P (current_function_decl) = false;
+ changed = true;
+ if (dump_file)
+ fprintf (dump_file, "Function found to be non-looping: %s\n",
+ lang_hooks.decl_printable_name (current_function_decl,
+ 2));
+ }
+ break;
+
+ default:
+ break;
+ }
+ if (!l->can_throw && !TREE_NOTHROW (current_function_decl))
+ {
+ 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",
+ lang_hooks.decl_printable_name (current_function_decl,
+ 2));
+ }
+ if (l)
+ free (l);
+ if (changed)
+ return execute_fixup_cfg ();
+ else
+ return 0;
+}
+
+struct gimple_opt_pass pass_local_pure_const =
+{
+ {
+ GIMPLE_PASS,
+ "local-pure-const", /* name */
+ gate_pure_const, /* gate */
+ local_pure_const, /* execute */
+ NULL, /* sub */
+ NULL, /* next */
+ 0, /* static_pass_number */
+ TV_IPA_PURE_CONST, /* tv_id */
+ 0, /* properties_required */
+ 0, /* properties_provided */
+ 0, /* properties_destroyed */
+ 0, /* todo_flags_start */
+ 0 /* todo_flags_finish */
+ }
+};
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