/* Callgraph based analysis of static variables.
- Copyright (C) 2004, 2005, 2007, 2008 Free Software Foundation, Inc.
+ Copyright (C) 2004, 2005, 2007, 2008, 2009, 2010
+ 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 "flags.h"
#include "timevar.h"
+#include "toplev.h"
#include "diagnostic.h"
#include "langhooks.h"
#include "target.h"
+#include "lto-streamer.h"
+#include "cfgloop.h"
+#include "tree-scalar-evolution.h"
+#include "intl.h"
+#include "opts.h"
static struct pointer_set_t *visited_nodes;
/* Holder for the const_state. There is one of these per function
decl. */
-struct funct_state_d
+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
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;
+ 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. */
+ local info. */
/* Array, indexed by cgraph node uid, of function states. */
-static funct_state *funct_state_vec;
+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. */
+/* Try to guess if function body will always be visible to compiler
+ when compiling the call and whether compiler will be able
+ to propagate the information by itself. */
-static void
-init_state (void)
+static bool
+function_always_visible_to_compiler_p (tree decl)
{
- funct_state_vec = XCNEWVEC (funct_state, cgraph_max_uid);
+ return (!TREE_PUBLIC (decl) || DECL_DECLARED_INLINE_P (decl));
+}
+
+/* Emit suggestion about attribute ATTRIB_NAME for DECL. KNOWN_FINITE
+ is true if the function is known to be finite. The diagnostic is
+ controlled by OPTION. WARNED_ABOUT is a pointer_set unique for
+ OPTION, this function may initialize it and it is always returned
+ by the function. */
+
+static struct pointer_set_t *
+suggest_attribute (int option, tree decl, bool known_finite,
+ struct pointer_set_t *warned_about,
+ const char * attrib_name)
+{
+ if (!option_enabled (option))
+ return warned_about;
+ if (TREE_THIS_VOLATILE (decl)
+ || (known_finite && function_always_visible_to_compiler_p (decl)))
+ return warned_about;
+
+ if (!warned_about)
+ warned_about = pointer_set_create ();
+ if (pointer_set_contains (warned_about, decl))
+ return warned_about;
+ pointer_set_insert (warned_about, decl);
+ warning_at (DECL_SOURCE_LOCATION (decl),
+ option,
+ known_finite
+ ? _("function might be candidate for attribute %<%s%>")
+ : _("function might be candidate for attribute %<%s%>"
+ " if it is known to return normally"), attrib_name);
+ return warned_about;
+}
+
+/* Emit suggestion about __attribute_((pure)) for DECL. KNOWN_FINITE
+ is true if the function is known to be finite. */
+
+static void
+warn_function_pure (tree decl, bool known_finite)
+{
+ static struct pointer_set_t *warned_about;
+
+ warned_about
+ = suggest_attribute (OPT_Wsuggest_attribute_pure, decl,
+ known_finite, warned_about, "pure");
}
+/* Emit suggestion about __attribute_((const)) for DECL. KNOWN_FINITE
+ is true if the function is known to be finite. */
+static void
+warn_function_const (tree decl, bool known_finite)
+{
+ static struct pointer_set_t *warned_about;
+ warned_about
+ = suggest_attribute (OPT_Wsuggest_attribute_const, decl,
+ known_finite, warned_about, "const");
+}
/* Init the function state. */
static void
}
-/* Return the function state from NODE. */
+/* Return the function state from NODE. */
static inline funct_state
get_function_state (struct cgraph_node *node)
{
- return funct_state_vec[node->uid];
+ 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)
{
- funct_state_vec[node->uid] = 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)
variable T is legal in a function that is either pure or const. */
-static inline void
-check_decl (funct_state local,
+static inline void
+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))
- {
+ 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 (DECL_PRESERVE_P (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)
+ 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. */
- else
+ /* 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))
+ 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 (TREE_CODE (t) == ARRAY_REF)
- check_operand (local, TREE_OPERAND (t, 1), false);
- t = TREE_OPERAND (t, 0);
+ if (dump_file)
+ fprintf (dump_file, " Indirect ref to local memory is OK\n");
+ return;
}
-
- /* The bottom of an indirect reference can only be read, not
- written. */
- if (INDIRECT_REF_P (t))
+ else if (checking_write)
{
- 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;
+ local->pure_const_state = IPA_NEITHER;
+ if (dump_file)
+ fprintf (dump_file, " Indirect ref write is not const/pure\n");
+ return;
}
-
- 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)
+ else
{
- 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 read is not const\n");
+ if (local->pure_const_state == IPA_CONST)
+ local->pure_const_state = IPA_PURE;
}
}
-/* 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, gimple stmt)
-{
- size_t noutputs = gimple_asm_noutputs (stmt);
- const char **oconstraints
- = (const char **) alloca ((noutputs) * sizeof (const char *));
- size_t i;
- tree op;
- const char *constraint;
- bool allows_mem, allows_reg, is_inout;
-
- for (i = 0; i < noutputs; i++)
- {
- op = gimple_asm_output_op (stmt, i);
- oconstraints[i] = constraint
- = 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 (op));
- }
-
- for (i = 0; i < gimple_asm_ninputs (stmt); i++)
- {
- op = gimple_asm_input_op (stmt, i);
- constraint
- = 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 (op));
- }
-
- 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 (gimple_asm_volatile_p (stmt))
- local->pure_const_state = IPA_NEITHER;
-}
-
/* Check the parameters of a function call to CALL_EXPR to see if
there are any references in the parameters that are not allowed for
pure or const functions. Also check to see if this is either an
the entire call expression. */
static void
-check_call (funct_state local, gimple call)
+check_call (funct_state local, gimple call, bool ipa)
{
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;
-
- 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));
-
+ tree callee_t = gimple_call_fndecl (call);
+ bool possibly_throws = stmt_could_throw_p (call);
+ bool possibly_throws_externally = (possibly_throws
+ && stmt_can_throw_external (call));
+
+ 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
for the callee, (such as for some of the builtins) we will use
- them, otherwise we will compute our own information.
-
+ them, otherwise we will compute our own information.
+
Const and pure functions have less clobber effects than other
functions so we process these first. Otherwise if it is a call
outside the compilation unit or an indirect call we punt. This
leaves local calls which will be processed by following the call
- graph. */
+ graph. */
if (callee_t)
{
- callee = cgraph_node(callee_t);
- avail = cgraph_function_body_availability (callee);
-
/* When bad things happen to bad functions, they cannot be const
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;
}
}
- /* 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)
+ /* When not in IPA mode, we can still handle self recursion. */
+ if (!ipa && callee_t == current_function_decl)
{
- if (flags & ECF_PURE)
- {
- if (local->pure_const_state == IPA_CONST)
- local->pure_const_state = IPA_PURE;
- }
- else
- local->pure_const_state = IPA_NEITHER;
+ if (dump_file)
+ fprintf (dump_file, " Recursive call can loop.\n");
+ local->looping = true;
}
- else
+ /* 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)
{
- /* We have the code and we will scan it for the effects. */
- 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))
+ {
+ if (dump_file)
+ fprintf (dump_file, " calls looping pure.\n");
+ local->looping = true;
+ }
+ }
+ else if (flags & ECF_PURE)
+ {
+ if (callee_t && DECL_LOOPING_CONST_OR_PURE_P (callee_t))
+ {
+ if (dump_file)
+ fprintf (dump_file, " calls looping const.\n");
+ 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
+ {
+ 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. */
-
-/* FIXME: When this is converted to run over SSA form, this code
- should be converted to use the operand scanner. */
+/* Wrapper around check_decl for loads. */
-static tree
-scan_function_op (tree *tp, int *walk_subtrees, void *data)
+static bool
+check_load (gimple stmt ATTRIBUTE_UNUSED, tree op, void *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);
-
- switch (TREE_CODE (t))
- {
- case VAR_DECL:
- if (DECL_INITIAL (t))
- walk_tree (&DECL_INITIAL (t), scan_function_op, data, visited_nodes);
- *walk_subtrees = 0;
- break;
+ if (DECL_P (op))
+ check_decl ((funct_state)data, op, false);
+ else
+ check_op ((funct_state)data, op, false);
+ return false;
+}
- 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;
+/* Wrapper around check_decl for stores. */
- default:
- break;
- }
- return NULL;
+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;
}
-static tree
-scan_function_stmt (gimple_stmt_iterator *gsi_p,
- bool *handled_ops_p,
- struct walk_stmt_info *wi)
+/* 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)
{
- struct cgraph_node *fn = (struct cgraph_node *) wi->info;
- gimple stmt = gsi_stmt (*gsi_p);
- funct_state local = get_function_state (fn);
+ gimple stmt = gsi_stmt (*gsip);
+ unsigned int i = 0;
- switch (gimple_code (stmt))
- {
- case GIMPLE_ASSIGN:
- {
- /* First look on the lhs and see what variable is stored to */
- 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);
+ if (is_gimple_debug (stmt))
+ return;
- /* For the purposes of figuring out what the cast affects */
+ if (dump_file)
+ {
+ fprintf (dump_file, " scanning: ");
+ print_gimple_stmt (dump_file, stmt, 0, 0);
+ }
- /* Next check the operands on the rhs to see if they are ok. */
- switch (TREE_CODE_CLASS (code))
- {
- case tcc_binary:
- {
- check_rhs_var (local, rhs1);
- check_rhs_var (local, rhs2);
- }
- break;
- case tcc_unary:
- {
- check_rhs_var (local, rhs1);
- }
+ /* Look for loads and stores. */
+ walk_stmt_load_store_ops (stmt, local, check_load, check_store);
- break;
- case tcc_reference:
- check_rhs_var (local, rhs1);
- break;
- case tcc_declaration:
- check_rhs_var (local, rhs1);
- break;
- case tcc_expression:
- switch (code)
- {
- case ADDR_EXPR:
- check_rhs_var (local, rhs1);
- break;
- default:
- break;
- }
- break;
- default:
- break;
- }
- *handled_ops_p = true;
- }
+ 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 GIMPLE_CALL:
- check_call (local, stmt);
- *handled_ops_p = true;
- break;
-
case GIMPLE_ASM:
- get_asm_expr_operands (local, stmt);
- *handled_ops_p = true;
- break;
-
+ 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)
{
tree decl = fn->decl;
- funct_state l = XCNEW (struct funct_state_d);
-
- set_function_state (fn, l);
+ tree old_decl = current_function_decl;
+ funct_state l;
+ basic_block this_block;
+ 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)
- {
- gimple_stmt_iterator gsi;
- struct walk_stmt_info wi;
+ return l;
+}
- memset (&wi, 0, sizeof(wi));
- for (gsi = gsi_start_bb (this_block);
- !gsi_end_p (gsi);
- gsi_next (&gsi))
- {
- 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 ();
+ if (cgraph_function_body_availability (node) > AVAIL_OVERWRITABLE)
+ set_function_state (node, analyze_function (node, true));
+ pointer_set_destroy (visited_nodes);
+ visited_nodes = NULL;
+}
- 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 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
+static void
+register_hooks (void)
+{
+ 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);
+ 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);
+}
+
+
/* Analyze each function in the cgraph to see if it is locally PURE or
CONST. */
-static void
+static void
generate_summary (void)
{
struct cgraph_node *node;
- init_state ();
+ 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
operations. */
visited_nodes = pointer_set_create ();
- /* Process all of the functions.
+ /* Process all of the functions.
+
+ 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. */
- 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
- 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;
}
+
+/* Serialize the ipa info for lto. */
+
+static void
+pure_const_write_summary (cgraph_node_set set,
+ varpool_node_set vset ATTRIBUTE_UNUSED)
+{
+ 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
int i;
struct ipa_dfs_info * w_info;
- order_pos = ipa_utils_reduced_inorder (order, true, false);
+ 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 (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)
+ 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);
+ 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;
+ }
+ else
+ {
+ int flags = flags_from_decl_or_type (y->decl);
- if (w == y)
+ if (flags & ECF_LOOPING_CONST_OR_PURE)
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;
- }
+ 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;
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 = pure_const_state;
- w_l->looping = looping;
+ w_l->pure_const_state = this_state;
+ w_l->looping = this_looping;
- switch (pure_const_state)
+ switch (this_state)
+ {
+ case IPA_CONST:
+ if (!TREE_READONLY (w->decl))
{
- case IPA_CONST:
- TREE_READONLY (w->decl) = 1;
- DECL_LOOPING_CONST_OR_PURE_P (w->decl) = looping;
+ warn_function_const (w->decl, !this_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;
+ fprintf (dump_file, "Function found to be %sconst: %s\n",
+ this_looping ? "looping " : "",
+ cgraph_node_name (w));
+ }
+ cgraph_set_readonly_flag (w, true);
+ cgraph_set_looping_const_or_pure_flag (w, this_looping);
+ break;
+
+ case IPA_PURE:
+ if (!DECL_PURE_P (w->decl))
+ {
+ warn_function_pure (w->decl, !this_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;
+ fprintf (dump_file, "Function found to be %spure: %s\n",
+ this_looping ? "looping " : "",
+ cgraph_node_name (w));
+ }
+ cgraph_set_pure_flag (w, true);
+ cgraph_set_looping_const_or_pure_flag (w, 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
+ || 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))
+ {
+ struct cgraph_edge *e;
+ cgraph_set_nothrow_flag (w, 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. */
free (node->aux);
node->aux = NULL;
}
- if (node->analyzed && cgraph_is_master_clone (node))
+ 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_ipa_pure_const
+ return (flag_ipa_pure_const
/* Don't bother doing anything if the program has errors. */
&& !(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 */
- NULL, /* function_read_summary */
+ pure_const_write_summary, /* write_summary */
+ pure_const_read_summary, /* read_summary */
+ NULL, /* write_optimization_summary */
+ NULL, /* read_optimization_summary */
+ NULL, /* stmt_fixup */
0, /* TODOs */
NULL, /* function_transform */
NULL /* variable_transform */
};
+
+/* Return true if function should be skipped for local pure const analysis. */
+
+static bool
+skip_function_for_local_pure_const (struct cgraph_node *node)
+{
+ /* 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 true;
+ }
+ if (cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE)
+ {
+ if (dump_file)
+ fprintf (dump_file, "Function is not available or overwrittable; not analyzing.\n");
+ return true;
+ }
+ return false;
+}
+
+/* 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;
+ bool skip;
+ struct cgraph_node *node;
+
+ node = cgraph_node (current_function_decl);
+ skip = skip_function_for_local_pure_const (node);
+ if (!warn_suggest_attribute_const
+ && !warn_suggest_attribute_pure
+ && skip)
+ return 0;
+ l = analyze_function (node, false);
+
+ switch (l->pure_const_state)
+ {
+ case IPA_CONST:
+ if (!TREE_READONLY (current_function_decl))
+ {
+ warn_function_const (current_function_decl, !l->looping);
+ if (!skip)
+ {
+ cgraph_set_readonly_flag (node, true);
+ cgraph_set_looping_const_or_pure_flag (node, 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)
+ {
+ if (!skip)
+ {
+ cgraph_set_looping_const_or_pure_flag (node, 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 (!DECL_PURE_P (current_function_decl))
+ {
+ if (!skip)
+ {
+ cgraph_set_pure_flag (node, true);
+ cgraph_set_looping_const_or_pure_flag (node, l->looping);
+ changed = true;
+ }
+ warn_function_pure (current_function_decl, !l->looping);
+ 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)
+ {
+ if (!skip)
+ {
+ cgraph_set_looping_const_or_pure_flag (node, 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;
+
+ cgraph_set_nothrow_flag (node, true);
+ for (e = node->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 */
+ }
+};