+++ /dev/null
-/* Callgraph based analysis of static variables.
- Copyright (C) 2004-2021 Free Software Foundation, Inc.
- Contributed by Kenneth Zadeck <zadeck@naturalbridge.com>
-
-This file is part of GCC.
-
-GCC is free software; you can redistribute it and/or modify it under
-the terms of the GNU General Public License as published by the Free
-Software Foundation; either version 3, or (at your option) any later
-version.
-
-GCC is distributed in the hope that it will be useful, but WITHOUT ANY
-WARRANTY; without even the implied warranty of MERCHANTABILITY or
-FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
-for more details.
-
-You should have received a copy of the GNU General Public License
-along with GCC; see the file COPYING3. If not see
-<http://www.gnu.org/licenses/>. */
-
-/* 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
- consistent with post inlined state. The global sets are not prone
- to this problem since they are by definition transitive. */
-
-/* The code in this module is called by the ipa pass manager. It
- should be one of the later passes since it's information is used by
- the rest of the compilation. */
-
-#include "config.h"
-#include "system.h"
-#include "coretypes.h"
-#include "backend.h"
-#include "target.h"
-#include "tree.h"
-#include "gimple.h"
-#include "tree-pass.h"
-#include "tree-streamer.h"
-#include "cgraph.h"
-#include "diagnostic.h"
-#include "calls.h"
-#include "cfganal.h"
-#include "tree-eh.h"
-#include "gimple-iterator.h"
-#include "gimple-walk.h"
-#include "tree-cfg.h"
-#include "tree-ssa-loop-niter.h"
-#include "langhooks.h"
-#include "ipa-utils.h"
-#include "gimple-pretty-print.h"
-#include "cfgloop.h"
-#include "tree-scalar-evolution.h"
-#include "intl.h"
-#include "opts.h"
-#include "ssa.h"
-#include "alloc-pool.h"
-#include "symbol-summary.h"
-#include "ipa-prop.h"
-#include "ipa-fnsummary.h"
-#include "symtab-thunks.h"
-#include "dbgcnt.h"
-
-/* Lattice values for const and pure functions. Everything starts out
- being const, then may drop to pure and then neither depending on
- what is found. */
-enum pure_const_state_e
-{
- IPA_CONST,
- IPA_PURE,
- IPA_NEITHER
-};
-
-static const char *pure_const_names[3] = {"const", "pure", "neither"};
-
-enum malloc_state_e
-{
- STATE_MALLOC_TOP,
- STATE_MALLOC,
- STATE_MALLOC_BOTTOM
-};
-
-static const char *malloc_state_names[] = {"malloc_top", "malloc", "malloc_bottom"};
-
-/* Holder for the const_state. There is one of these per function
- decl. */
-class funct_state_d
-{
-public:
- funct_state_d (): pure_const_state (IPA_NEITHER),
- state_previously_known (IPA_NEITHER), looping_previously_known (true),
- looping (true), can_throw (true), can_free (true),
- malloc_state (STATE_MALLOC_BOTTOM) {}
-
- funct_state_d (const funct_state_d &s): pure_const_state (s.pure_const_state),
- state_previously_known (s.state_previously_known),
- looping_previously_known (s.looping_previously_known),
- looping (s.looping), can_throw (s.can_throw), can_free (s.can_free),
- malloc_state (s.malloc_state) {}
-
- /* 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 can_throw;
-
- /* If function can call free, munmap or otherwise make previously
- non-trapping memory accesses trapping. */
- bool can_free;
-
- enum malloc_state_e malloc_state;
-};
-
-typedef class 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. */
-
-class funct_state_summary_t:
- public fast_function_summary <funct_state_d *, va_heap>
-{
-public:
- funct_state_summary_t (symbol_table *symtab):
- fast_function_summary <funct_state_d *, va_heap> (symtab) {}
-
- virtual void insert (cgraph_node *, funct_state_d *state);
- virtual void duplicate (cgraph_node *src_node, cgraph_node *dst_node,
- funct_state_d *src_data,
- funct_state_d *dst_data);
-};
-
-static funct_state_summary_t *funct_state_summaries = NULL;
-
-static bool gate_pure_const (void);
-
-namespace {
-
-const pass_data pass_data_ipa_pure_const =
-{
- IPA_PASS, /* type */
- "pure-const", /* name */
- OPTGROUP_NONE, /* optinfo_flags */
- TV_IPA_PURE_CONST, /* tv_id */
- 0, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- 0, /* todo_flags_finish */
-};
-
-class pass_ipa_pure_const : public ipa_opt_pass_d
-{
-public:
- pass_ipa_pure_const(gcc::context *ctxt);
-
- /* opt_pass methods: */
- bool gate (function *) { return gate_pure_const (); }
- unsigned int execute (function *fun);
-
- void register_hooks (void);
-
-private:
- bool init_p;
-}; // class pass_ipa_pure_const
-
-} // anon namespace
-
-/* 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 bool
-function_always_visible_to_compiler_p (tree decl)
-{
- return (!TREE_PUBLIC (decl) || DECL_DECLARED_INLINE_P (decl)
- || DECL_COMDAT (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 hash_set<tree> unique for
- OPTION, this function may initialize it and it is always returned
- by the function. */
-
-static hash_set<tree> *
-suggest_attribute (int option, tree decl, bool known_finite,
- hash_set<tree> *warned_about,
- const char * attrib_name)
-{
- if (!option_enabled (option, lang_hooks.option_lang_mask (), &global_options))
- 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 = new hash_set<tree>;
- if (warned_about->contains (decl))
- return warned_about;
- warned_about->add (decl);
- warning_at (DECL_SOURCE_LOCATION (decl),
- option,
- known_finite
- ? G_("function might be candidate for attribute %qs")
- : G_("function might be candidate for attribute %qs"
- " 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)
-{
- /* Declaring a void function pure makes no sense and is diagnosed
- by -Wattributes because calling it would have no effect. */
- if (VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
- return;
-
- static hash_set<tree> *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)
-{
- /* Declaring a void function const makes no sense is diagnosed
- by -Wattributes because calling it would have no effect. */
- if (VOID_TYPE_P (TREE_TYPE (TREE_TYPE (decl))))
- return;
-
- static hash_set<tree> *warned_about;
- warned_about
- = suggest_attribute (OPT_Wsuggest_attribute_const, decl,
- known_finite, warned_about, "const");
-}
-
-/* Emit suggestion about __attribute__((malloc)) for DECL. */
-
-static void
-warn_function_malloc (tree decl)
-{
- static hash_set<tree> *warned_about;
- warned_about
- = suggest_attribute (OPT_Wsuggest_attribute_malloc, decl,
- true, warned_about, "malloc");
-}
-
-/* Emit suggestion about __attribute__((noreturn)) for DECL. */
-
-static void
-warn_function_noreturn (tree decl)
-{
- tree original_decl = decl;
-
- static hash_set<tree> *warned_about;
- if (!lang_hooks.missing_noreturn_ok_p (decl)
- && targetm.warn_func_return (decl))
- warned_about
- = suggest_attribute (OPT_Wsuggest_attribute_noreturn, original_decl,
- true, warned_about, "noreturn");
-}
-
-void
-warn_function_cold (tree decl)
-{
- tree original_decl = decl;
-
- static hash_set<tree> *warned_about;
- warned_about
- = suggest_attribute (OPT_Wsuggest_attribute_cold, original_decl,
- true, warned_about, "cold");
-}
-
-/* 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,
- tree t, bool checking_write, bool ipa)
-{
- /* 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;
- if (dump_file)
- fprintf (dump_file, " Volatile operand is not const/pure\n");
- return;
- }
-
- /* Do not care about a local automatic that is not static. */
- 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;
- }
-
- /* In IPA mode we are not interested in checking actual loads and stores;
- they will be processed at propagation time using ipa_ref. */
- if (ipa)
- 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;
- if (dump_file)
- fprintf (dump_file, " static/global memory write is not const/pure\n");
- return;
- }
-
- if (DECL_EXTERNAL (t) || TREE_PUBLIC (t))
- {
- /* Readonly reads are safe. */
- if (TREE_READONLY (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;
- }
- }
- 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;
- }
-}
-
-
-/* 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_op (funct_state local, tree t, bool checking_write)
-{
- t = get_base_address (t);
- if (t && TREE_THIS_VOLATILE (t))
- {
- local->pure_const_state = IPA_NEITHER;
- if (dump_file)
- fprintf (dump_file, " Volatile indirect ref is not const/pure\n");
- return;
- }
- else if (refs_local_or_readonly_memory_p (t))
- {
- if (dump_file)
- fprintf (dump_file, " Indirect ref to local or readonly "
- "memory is OK\n");
- return;
- }
- else if (checking_write)
- {
- local->pure_const_state = IPA_NEITHER;
- if (dump_file)
- fprintf (dump_file, " Indirect ref write is not const/pure\n");
- return;
- }
- else
- {
- 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;
- }
-}
-
-/* compute state based on ECF FLAGS and store to STATE and LOOPING. */
-
-static void
-state_from_flags (enum pure_const_state_e *state, bool *looping,
- int flags, bool cannot_lead_to_return)
-{
- *looping = false;
- if (flags & ECF_LOOPING_CONST_OR_PURE)
- {
- *looping = true;
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " looping\n");
- }
- if (flags & ECF_CONST)
- {
- *state = IPA_CONST;
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " const\n");
- }
- else if (flags & ECF_PURE)
- {
- *state = IPA_PURE;
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " pure\n");
- }
- else if (cannot_lead_to_return)
- {
- *state = IPA_PURE;
- *looping = true;
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " ignoring side effects->pure looping\n");
- }
- else
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " neither\n");
- *state = IPA_NEITHER;
- *looping = true;
- }
-}
-
-/* Merge STATE and STATE2 and LOOPING and LOOPING2 and store
- into STATE and LOOPING better of the two variants.
- Be sure to merge looping correctly. IPA_NEITHER functions
- have looping 0 even if they don't have to return. */
-
-static inline void
-better_state (enum pure_const_state_e *state, bool *looping,
- enum pure_const_state_e state2, bool looping2)
-{
- if (state2 < *state)
- {
- if (*state == IPA_NEITHER)
- *looping = looping2;
- else
- *looping = MIN (*looping, looping2);
- *state = state2;
- }
- else if (state2 != IPA_NEITHER)
- *looping = MIN (*looping, looping2);
-}
-
-/* Merge STATE and STATE2 and LOOPING and LOOPING2 and store
- into STATE and LOOPING worse of the two variants.
- N is the actual node called. */
-
-static inline void
-worse_state (enum pure_const_state_e *state, bool *looping,
- enum pure_const_state_e state2, bool looping2,
- struct symtab_node *from,
- struct symtab_node *to)
-{
- /* Consider function:
-
- bool a(int *p)
- {
- return *p==*p;
- }
-
- During early optimization we will turn this into:
-
- bool a(int *p)
- {
- return true;
- }
-
- Now if this function will be detected as CONST however when interposed it
- may end up being just pure. We always must assume the worst scenario here.
- */
- if (*state == IPA_CONST && state2 == IPA_CONST
- && to && !TREE_READONLY (to->decl) && !to->binds_to_current_def_p (from))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "Dropping state to PURE because call to %s may not "
- "bind to current def.\n", to->dump_name ());
- state2 = IPA_PURE;
- }
- *state = MAX (*state, state2);
- *looping = MAX (*looping, looping2);
-}
-
-/* Recognize special cases of builtins that are by themselves not const
- but function using them is. */
-bool
-builtin_safe_for_const_function_p (bool *looping, tree callee)
-{
- if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL)
- switch (DECL_FUNCTION_CODE (callee))
- {
- case BUILT_IN_RETURN:
- case BUILT_IN_UNREACHABLE:
- CASE_BUILT_IN_ALLOCA:
- case BUILT_IN_STACK_SAVE:
- case BUILT_IN_STACK_RESTORE:
- case BUILT_IN_EH_POINTER:
- case BUILT_IN_EH_FILTER:
- case BUILT_IN_UNWIND_RESUME:
- case BUILT_IN_CXA_END_CLEANUP:
- case BUILT_IN_EH_COPY_VALUES:
- case BUILT_IN_FRAME_ADDRESS:
- case BUILT_IN_APPLY_ARGS:
- case BUILT_IN_ASAN_BEFORE_DYNAMIC_INIT:
- case BUILT_IN_ASAN_AFTER_DYNAMIC_INIT:
- case BUILT_IN_DWARF_CFA:
- case BUILT_IN_RETURN_ADDRESS:
- *looping = false;
- return true;
- case BUILT_IN_PREFETCH:
- *looping = true;
- return true;
- default:
- break;
- }
- return false;
-}
-
-/* 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
- indirect call, a call outside the compilation unit, or has special
- attributes that may also effect the purity. The CALL_EXPR node for
- the entire call expression. */
-
-static void
-check_call (funct_state local, gcall *call, bool ipa)
-{
- int flags = gimple_call_flags (call);
- tree callee_t = gimple_call_fndecl (call);
- bool possibly_throws = stmt_could_throw_p (cfun, call);
- bool possibly_throws_externally = (possibly_throws
- && stmt_can_throw_external (cfun, 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 && cfun->can_throw_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.
-
- 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. */
- if (callee_t)
- {
- bool call_looping;
-
- if (gimple_call_builtin_p (call, BUILT_IN_NORMAL)
- && !nonfreeing_call_p (call))
- local->can_free = true;
-
- if (builtin_safe_for_const_function_p (&call_looping, callee_t))
- {
- worse_state (&local->pure_const_state, &local->looping,
- IPA_CONST, call_looping,
- NULL, NULL);
- return;
- }
- /* 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;
- }
-
- 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:
- if (dump_file)
- fprintf (dump_file,
- " longjmp and nonlocal goto is not const/pure\n");
- local->pure_const_state = IPA_NEITHER;
- local->looping = true;
- break;
- default:
- break;
- }
- }
- else if (gimple_call_internal_p (call) && !nonfreeing_call_p (call))
- local->can_free = true;
-
- /* When not in IPA mode, we can still handle self recursion. */
- if (!ipa && callee_t
- && recursive_call_p (current_function_decl, callee_t))
- {
- if (dump_file)
- fprintf (dump_file, " Recursive call can loop.\n");
- local->looping = true;
- }
- /* Either callee 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. Handle internal calls always, those calls don't have
- corresponding cgraph edges and thus aren't processed during
- the propagation. */
- else if (!ipa || gimple_call_internal_p (call))
- {
- enum pure_const_state_e call_state;
- bool call_looping;
- if (possibly_throws && cfun->can_throw_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 (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " checking flags for call:");
- state_from_flags (&call_state, &call_looping, flags,
- ((flags & (ECF_NORETURN | ECF_NOTHROW))
- == (ECF_NORETURN | ECF_NOTHROW))
- || (!flag_exceptions && (flags & ECF_NORETURN)));
- worse_state (&local->pure_const_state, &local->looping,
- call_state, call_looping, NULL, NULL);
- }
- /* Direct functions calls are handled by IPA propagation. */
-}
-
-/* Wrapper around check_decl for loads in local more. */
-
-static bool
-check_load (gimple *, tree op, tree, void *data)
-{
- if (DECL_P (op))
- check_decl ((funct_state)data, op, false, false);
- else
- check_op ((funct_state)data, op, false);
- return false;
-}
-
-/* Wrapper around check_decl for stores in local more. */
-
-static bool
-check_store (gimple *, tree op, tree, void *data)
-{
- if (DECL_P (op))
- check_decl ((funct_state)data, op, true, false);
- else
- check_op ((funct_state)data, op, true);
- return false;
-}
-
-/* Wrapper around check_decl for loads in ipa mode. */
-
-static bool
-check_ipa_load (gimple *, tree op, tree, void *data)
-{
- if (DECL_P (op))
- check_decl ((funct_state)data, op, false, true);
- else
- check_op ((funct_state)data, op, false);
- return false;
-}
-
-/* Wrapper around check_decl for stores in ipa mode. */
-
-static bool
-check_ipa_store (gimple *, tree op, tree, void *data)
-{
- if (DECL_P (op))
- check_decl ((funct_state)data, op, true, true);
- else
- check_op ((funct_state)data, op, true);
- return false;
-}
-
-/* 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);
-
- if (is_gimple_debug (stmt))
- return;
-
- /* Do consider clobber as side effects before IPA, so we rather inline
- C++ destructors and keep clobber semantics than eliminate them.
-
- Similar logic is in ipa-modref.
-
- TODO: We may get smarter during early optimizations on these and let
- functions containing only clobbers to be optimized more. This is a common
- case of C++ destructors. */
-
- if ((ipa || cfun->after_inlining) && gimple_clobber_p (stmt))
- return;
-
- if (dump_file)
- {
- fprintf (dump_file, " scanning: ");
- print_gimple_stmt (dump_file, stmt, 0);
- }
-
- if (gimple_has_volatile_ops (stmt)
- && !gimple_clobber_p (stmt))
- {
- local->pure_const_state = IPA_NEITHER;
- if (dump_file)
- fprintf (dump_file, " Volatile stmt is not const/pure\n");
- }
-
- /* Look for loads and stores. */
- walk_stmt_load_store_ops (stmt, local,
- ipa ? check_ipa_load : check_load,
- ipa ? check_ipa_store : check_store);
-
- if (gimple_code (stmt) != GIMPLE_CALL
- && stmt_could_throw_p (cfun, stmt))
- {
- if (cfun->can_throw_non_call_exceptions)
- {
- if (dump_file)
- fprintf (dump_file, " can throw; looping\n");
- local->looping = true;
- }
- if (stmt_can_throw_external (cfun, stmt))
- {
- if (dump_file)
- fprintf (dump_file, " can throw externally\n");
- local->can_throw = true;
- }
- else
- if (dump_file)
- fprintf (dump_file, " can throw\n");
- }
- switch (gimple_code (stmt))
- {
- case GIMPLE_CALL:
- check_call (local, as_a <gcall *> (stmt), ipa);
- break;
- case GIMPLE_LABEL:
- if (DECL_NONLOCAL (gimple_label_label (as_a <glabel *> (stmt))))
- /* Target of long jump. */
- {
- if (dump_file)
- fprintf (dump_file, " nonlocal label is not const/pure\n");
- local->pure_const_state = IPA_NEITHER;
- }
- break;
- case GIMPLE_ASM:
- if (gimple_asm_clobbers_memory_p (as_a <gasm *> (stmt)))
- {
- if (dump_file)
- fprintf (dump_file, " memory asm clobber is not const/pure\n");
- /* Abandon all hope, ye who enter here. */
- local->pure_const_state = IPA_NEITHER;
- local->can_free = true;
- }
- if (gimple_asm_volatile_p (as_a <gasm *> (stmt)))
- {
- if (dump_file)
- fprintf (dump_file, " volatile is not const/pure\n");
- /* Abandon all hope, ye who enter here. */
- local->pure_const_state = IPA_NEITHER;
- local->looping = true;
- local->can_free = true;
- }
- return;
- default:
- break;
- }
-}
-
-/* Check that RETVAL is used only in STMT and in comparisons against 0.
- RETVAL is return value of the function and STMT is return stmt. */
-
-static bool
-check_retval_uses (tree retval, gimple *stmt)
-{
- imm_use_iterator use_iter;
- gimple *use_stmt;
-
- FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, retval)
- if (gcond *cond = dyn_cast<gcond *> (use_stmt))
- {
- tree op2 = gimple_cond_rhs (cond);
- if (!integer_zerop (op2))
- return false;
- }
- else if (gassign *ga = dyn_cast<gassign *> (use_stmt))
- {
- enum tree_code code = gimple_assign_rhs_code (ga);
- if (TREE_CODE_CLASS (code) != tcc_comparison)
- return false;
- if (!integer_zerop (gimple_assign_rhs2 (ga)))
- return false;
- }
- else if (is_gimple_debug (use_stmt))
- ;
- else if (use_stmt != stmt)
- return false;
-
- return true;
-}
-
-/* malloc_candidate_p() checks if FUN can possibly be annotated with malloc
- attribute. Currently this function does a very conservative analysis.
- FUN is considered to be a candidate if
- 1) It returns a value of pointer type.
- 2) SSA_NAME_DEF_STMT (return_value) is either a function call or
- a phi, and element of phi is either NULL or
- SSA_NAME_DEF_STMT(element) is function call.
- 3) The return-value has immediate uses only within comparisons (gcond or gassign)
- and return_stmt (and likewise a phi arg has immediate use only within comparison
- or the phi stmt). */
-
-#define DUMP_AND_RETURN(reason) \
-{ \
- if (dump_file && (dump_flags & TDF_DETAILS)) \
- fprintf (dump_file, "\n%s is not a malloc candidate, reason: %s\n", \
- (node->dump_name ()), (reason)); \
- return false; \
-}
-
-static bool
-malloc_candidate_p_1 (function *fun, tree retval, gimple *ret_stmt, bool ipa,
- bitmap visited)
-{
- cgraph_node *node = cgraph_node::get_create (fun->decl);
- if (!bitmap_set_bit (visited, SSA_NAME_VERSION (retval)))
- return true;
-
- if (!check_retval_uses (retval, ret_stmt))
- DUMP_AND_RETURN("Return value has uses outside return stmt"
- " and comparisons against 0.")
-
- gimple *def = SSA_NAME_DEF_STMT (retval);
-
- if (gcall *call_stmt = dyn_cast<gcall *> (def))
- {
- tree callee_decl = gimple_call_fndecl (call_stmt);
- if (!callee_decl)
- return false;
-
- if (!ipa && !DECL_IS_MALLOC (callee_decl))
- DUMP_AND_RETURN("callee_decl does not have malloc attribute for"
- " non-ipa mode.")
-
- cgraph_edge *cs = node->get_edge (call_stmt);
- if (cs)
- {
- ipa_call_summary *es = ipa_call_summaries->get_create (cs);
- es->is_return_callee_uncaptured = true;
- }
- }
-
- else if (gphi *phi = dyn_cast<gphi *> (def))
- {
- bool all_args_zero = true;
- for (unsigned i = 0; i < gimple_phi_num_args (phi); ++i)
- {
- tree arg = gimple_phi_arg_def (phi, i);
- if (integer_zerop (arg))
- continue;
-
- all_args_zero = false;
- if (TREE_CODE (arg) != SSA_NAME)
- DUMP_AND_RETURN ("phi arg is not SSA_NAME.");
- if (!check_retval_uses (arg, phi))
- DUMP_AND_RETURN ("phi arg has uses outside phi"
- " and comparisons against 0.")
-
- gimple *arg_def = SSA_NAME_DEF_STMT (arg);
- if (is_a<gphi *> (arg_def))
- {
- if (!malloc_candidate_p_1 (fun, arg, phi, ipa, visited))
- DUMP_AND_RETURN ("nested phi fail")
- continue;
- }
-
- gcall *call_stmt = dyn_cast<gcall *> (arg_def);
- if (!call_stmt)
- DUMP_AND_RETURN ("phi arg is a not a call_stmt.")
-
- tree callee_decl = gimple_call_fndecl (call_stmt);
- if (!callee_decl)
- return false;
- if (!ipa && !DECL_IS_MALLOC (callee_decl))
- DUMP_AND_RETURN("callee_decl does not have malloc attribute"
- " for non-ipa mode.")
-
- cgraph_edge *cs = node->get_edge (call_stmt);
- if (cs)
- {
- ipa_call_summary *es = ipa_call_summaries->get_create (cs);
- es->is_return_callee_uncaptured = true;
- }
- }
-
- if (all_args_zero)
- DUMP_AND_RETURN ("Return value is a phi with all args equal to 0.")
- }
-
- else
- DUMP_AND_RETURN("def_stmt of return value is not a call or phi-stmt.")
-
- return true;
-}
-
-static bool
-malloc_candidate_p (function *fun, bool ipa)
-{
- basic_block exit_block = EXIT_BLOCK_PTR_FOR_FN (fun);
- edge e;
- edge_iterator ei;
- cgraph_node *node = cgraph_node::get_create (fun->decl);
-
- if (EDGE_COUNT (exit_block->preds) == 0
- || !flag_delete_null_pointer_checks)
- return false;
-
- auto_bitmap visited;
- FOR_EACH_EDGE (e, ei, exit_block->preds)
- {
- gimple_stmt_iterator gsi = gsi_last_bb (e->src);
- greturn *ret_stmt = dyn_cast<greturn *> (gsi_stmt (gsi));
-
- if (!ret_stmt)
- return false;
-
- tree retval = gimple_return_retval (ret_stmt);
- if (!retval)
- DUMP_AND_RETURN("No return value.")
-
- if (TREE_CODE (retval) != SSA_NAME
- || TREE_CODE (TREE_TYPE (retval)) != POINTER_TYPE)
- DUMP_AND_RETURN("Return value is not SSA_NAME or not a pointer type.")
-
- if (!malloc_candidate_p_1 (fun, retval, ret_stmt, ipa, visited))
- return false;
- }
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "\nFound %s to be candidate for malloc attribute\n",
- IDENTIFIER_POINTER (DECL_NAME (fun->decl)));
- return true;
-}
-
-#undef DUMP_AND_RETURN
-
-/* Return true if function is known to be finite. */
-
-bool
-finite_function_p ()
-{
- /* Const functions cannot have back edges (an
- indication of possible infinite loop side
- effect. */
- bool finite = true;
- if (mark_dfs_back_edges ())
- {
- /* Preheaders are needed for SCEV to work.
- Simple latches 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_HAVE_PREHEADERS
- | LOOPS_HAVE_SIMPLE_LATCHES
- | 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");
- finite = false;
- }
- else
- {
- scev_initialize ();
- for (auto loop : loops_list (cfun, 0))
- if (!finite_loop_p (loop))
- {
- if (dump_file)
- fprintf (dump_file, " cannot prove finiteness of "
- "loop %i\n", loop->num);
- finite =false;
- break;
- }
- scev_finalize ();
- }
- loop_optimizer_finalize ();
- }
- return finite;
-}
-
-/* This is the main routine for finding the reference patterns for
- global variables within a function FN. */
-
-static funct_state
-analyze_function (struct cgraph_node *fn, bool ipa)
-{
- tree decl = fn->decl;
- funct_state l;
- basic_block this_block;
-
- l = XCNEW (class funct_state_d);
- l->pure_const_state = IPA_CONST;
- l->state_previously_known = IPA_NEITHER;
- l->looping_previously_known = true;
- l->looping = false;
- l->can_throw = false;
- l->can_free = false;
- state_from_flags (&l->state_previously_known, &l->looping_previously_known,
- flags_from_decl_or_type (fn->decl),
- fn->cannot_return_p ());
-
- if (fn->thunk || fn->alias)
- {
- /* Thunk gets propagated through, so nothing interesting happens. */
- gcc_assert (ipa);
- if (fn->thunk && thunk_info::get (fn)->virtual_offset_p)
- l->pure_const_state = IPA_NEITHER;
- return l;
- }
-
- if (dump_file)
- {
- fprintf (dump_file, "\n\n local analysis of %s\n ",
- fn->dump_name ());
- }
-
- push_cfun (DECL_STRUCT_FUNCTION (decl));
-
- FOR_EACH_BB_FN (this_block, cfun)
- {
- 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))
- {
- /* NULL memory accesses terminates BB. These accesses are known
- to trip undefined behaviour. gimple-ssa-isolate-paths turns them
- to volatile accesses and adds builtin_trap call which would
- confuse us otherwise. */
- if (infer_nonnull_range_by_dereference (gsi_stmt (gsi),
- null_pointer_node))
- {
- if (dump_file)
- fprintf (dump_file, " NULL memory access; terminating BB%s\n",
- flag_non_call_exceptions ? "; looping" : "");
- if (flag_non_call_exceptions)
- {
- l->looping = true;
- if (stmt_can_throw_external (cfun, gsi_stmt (gsi)))
- {
- if (dump_file)
- fprintf (dump_file, " can throw externally\n");
- l->can_throw = true;
- }
- }
- break;
- }
- check_stmt (&gsi, l, ipa);
- if (l->pure_const_state == IPA_NEITHER
- && l->looping
- && l->can_throw
- && l->can_free)
- goto end;
- }
- }
-
-end:
- if (l->pure_const_state != IPA_NEITHER
- && !l->looping
- && !finite_function_p ())
- l->looping = true;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " checking previously known:");
-
- better_state (&l->pure_const_state, &l->looping,
- l->state_previously_known,
- l->looping_previously_known);
- if (TREE_NOTHROW (decl))
- l->can_throw = false;
-
- l->malloc_state = STATE_MALLOC_BOTTOM;
- if (DECL_IS_MALLOC (decl))
- l->malloc_state = STATE_MALLOC;
- else if (ipa && malloc_candidate_p (DECL_STRUCT_FUNCTION (decl), true))
- l->malloc_state = STATE_MALLOC_TOP;
- else if (malloc_candidate_p (DECL_STRUCT_FUNCTION (decl), false))
- l->malloc_state = STATE_MALLOC;
-
- pop_cfun ();
- if (dump_file)
- {
- 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->can_free)
- fprintf (dump_file, "Function can locally free.\n");
- if (l->malloc_state == STATE_MALLOC)
- fprintf (dump_file, "Function is locally malloc.\n");
- }
- return l;
-}
-
-void
-funct_state_summary_t::insert (cgraph_node *node, funct_state_d *state)
-{
- /* 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. */
- if (opt_for_fn (node->decl, flag_ipa_pure_const))
- {
- funct_state_d *a = analyze_function (node, true);
- new (state) funct_state_d (*a);
- free (a);
- }
- else
- /* Do not keep stale summaries. */
- funct_state_summaries->remove (node);
-}
-
-/* Called when new clone is inserted to callgraph late. */
-
-void
-funct_state_summary_t::duplicate (cgraph_node *, cgraph_node *dst,
- funct_state_d *src_data,
- funct_state_d *dst_data)
-{
- new (dst_data) funct_state_d (*src_data);
- if (dst_data->malloc_state == STATE_MALLOC
- && VOID_TYPE_P (TREE_TYPE (TREE_TYPE (dst->decl))))
- dst_data->malloc_state = STATE_MALLOC_BOTTOM;
-}
-
-\f
-void
-pass_ipa_pure_const::
-register_hooks (void)
-{
- if (init_p)
- return;
-
- init_p = true;
-
- funct_state_summaries = new funct_state_summary_t (symtab);
-}
-
-
-/* Analyze each function in the cgraph to see if it is locally PURE or
- CONST. */
-
-static void
-pure_const_generate_summary (void)
-{
- struct cgraph_node *node;
-
- pass_ipa_pure_const *pass = static_cast <pass_ipa_pure_const *> (current_pass);
- pass->register_hooks ();
-
- /* Process all of the functions.
-
- We process AVAIL_INTERPOSABLE functions. We cannot use the results
- by default, but the info can be used at LTO with -fwhole-program or
- when function got cloned and the clone is AVAILABLE. */
-
- FOR_EACH_DEFINED_FUNCTION (node)
- if (opt_for_fn (node->decl, flag_ipa_pure_const))
- {
- funct_state_d *a = analyze_function (node, true);
- new (funct_state_summaries->get_create (node)) funct_state_d (*a);
- free (a);
- }
-}
-
-
-/* Serialize the ipa info for lto. */
-
-static void
-pure_const_write_summary (void)
-{
- struct cgraph_node *node;
- struct lto_simple_output_block *ob
- = lto_create_simple_output_block (LTO_section_ipa_pure_const);
- unsigned int count = 0;
- lto_symtab_encoder_iterator lsei;
- lto_symtab_encoder_t encoder;
-
- encoder = lto_get_out_decl_state ()->symtab_node_encoder;
-
- for (lsei = lsei_start_function_in_partition (encoder); !lsei_end_p (lsei);
- lsei_next_function_in_partition (&lsei))
- {
- node = lsei_cgraph_node (lsei);
- if (node->definition && funct_state_summaries->exists (node))
- count++;
- }
-
- streamer_write_uhwi_stream (ob->main_stream, count);
-
- /* Process all of the functions. */
- for (lsei = lsei_start_function_in_partition (encoder); !lsei_end_p (lsei);
- lsei_next_function_in_partition (&lsei))
- {
- node = lsei_cgraph_node (lsei);
- funct_state_d *fs = funct_state_summaries->get (node);
- if (node->definition && fs != NULL)
- {
- struct bitpack_d bp;
- int node_ref;
- lto_symtab_encoder_t encoder;
-
- encoder = ob->decl_state->symtab_node_encoder;
- node_ref = lto_symtab_encoder_encode (encoder, node);
- streamer_write_uhwi_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 (ob->main_stream);
- 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);
- bp_pack_value (&bp, fs->can_free, 1);
- bp_pack_value (&bp, fs->malloc_state, 2);
- streamer_write_bitpack (&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;
-
- pass_ipa_pure_const *pass = static_cast <pass_ipa_pure_const *> (current_pass);
- pass->register_hooks ();
-
- while ((file_data = file_data_vec[j++]))
- {
- const char *data;
- size_t len;
- class 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 = streamer_read_uhwi (ib);
-
- for (i = 0; i < count; i++)
- {
- unsigned int index;
- struct cgraph_node *node;
- struct bitpack_d bp;
- funct_state fs;
- lto_symtab_encoder_t encoder;
-
- index = streamer_read_uhwi (ib);
- encoder = file_data->symtab_node_encoder;
- node = dyn_cast<cgraph_node *> (lto_symtab_encoder_deref (encoder,
- index));
-
- fs = funct_state_summaries->get_create (node);
- /* Note that the flags must be read in the opposite
- order in which they were written (the bitflags were
- pushed into FLAGS). */
- bp = streamer_read_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);
- fs->can_free = bp_unpack_value (&bp, 1);
- fs->malloc_state
- = (enum malloc_state_e) bp_unpack_value (&bp, 2);
-
- if (dump_file)
- {
- int flags = flags_from_decl_or_type (node->decl);
- fprintf (dump_file, "Read info for %s ", node->dump_name ());
- if (flags & ECF_CONST)
- fprintf (dump_file, " const");
- if (flags & ECF_PURE)
- fprintf (dump_file, " pure");
- if (flags & ECF_NOTHROW)
- fprintf (dump_file, " nothrow");
- fprintf (dump_file, "\n pure const state: %s\n",
- pure_const_names[fs->pure_const_state]);
- fprintf (dump_file, " previously known state: %s\n",
- pure_const_names[fs->state_previously_known]);
- if (fs->looping)
- fprintf (dump_file," function is locally looping\n");
- if (fs->looping_previously_known)
- fprintf (dump_file," function is previously known looping\n");
- if (fs->can_throw)
- fprintf (dump_file," function is locally throwing\n");
- if (fs->can_free)
- fprintf (dump_file," function can locally free\n");
- fprintf (dump_file, "\n malloc state: %s\n",
- malloc_state_names[fs->malloc_state]);
- }
- }
-
- lto_destroy_simple_input_block (file_data,
- LTO_section_ipa_pure_const,
- ib, data, len);
- }
- }
-}
-
-/* We only propagate across edges that can throw externally and their callee
- is not interposable. */
-
-static bool
-ignore_edge_for_nothrow (struct cgraph_edge *e)
-{
- if (!e->can_throw_external || TREE_NOTHROW (e->callee->decl))
- return true;
-
- enum availability avail;
- cgraph_node *ultimate_target
- = e->callee->function_or_virtual_thunk_symbol (&avail, e->caller);
- if (avail <= AVAIL_INTERPOSABLE || TREE_NOTHROW (ultimate_target->decl))
- return true;
- return ((opt_for_fn (e->callee->decl, flag_non_call_exceptions)
- && !e->callee->binds_to_current_def_p (e->caller))
- || !opt_for_fn (e->caller->decl, flag_ipa_pure_const)
- || !opt_for_fn (ultimate_target->decl, flag_ipa_pure_const));
-}
-
-/* Return true if NODE is self recursive function.
- Indirectly recursive functions appears as non-trivial strongly
- connected components, so we need to care about self recursion
- only. */
-
-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->function_symbol () == node)
- return true;
- return false;
-}
-
-/* Return true if N is cdtor that is not const or pure. In this case we may
- need to remove unreachable function if it is marked const/pure. */
-
-static bool
-cdtor_p (cgraph_node *n, void *)
-{
- if (DECL_STATIC_CONSTRUCTOR (n->decl) || DECL_STATIC_DESTRUCTOR (n->decl))
- return ((!TREE_READONLY (n->decl) && !DECL_PURE_P (n->decl))
- || DECL_LOOPING_CONST_OR_PURE_P (n->decl));
- return false;
-}
-
-/* Skip edges from and to nodes without ipa_pure_const enabled.
- Ignore not available symbols. */
-
-static bool
-ignore_edge_for_pure_const (struct cgraph_edge *e)
-{
- enum availability avail;
- cgraph_node *ultimate_target
- = e->callee->function_or_virtual_thunk_symbol (&avail, e->caller);
-
- return (avail <= AVAIL_INTERPOSABLE
- || !opt_for_fn (e->caller->decl, flag_ipa_pure_const)
- || !opt_for_fn (ultimate_target->decl,
- flag_ipa_pure_const));
-}
-
-/* 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;
- }
- /* Save some work and do not analyze functions which are interposable and
- do not have any non-interposable aliases. */
- if (node->get_availability () <= AVAIL_INTERPOSABLE
- && !flag_lto
- && !node->has_aliases_p ())
- {
- if (dump_file)
- fprintf (dump_file,
- "Function is interposable; not analyzing.\n");
- return true;
- }
- return false;
-}
-
-/* Make function const and output warning. If LOCAL is true,
- return true if anything changed. Otherwise return true if
- we may have introduced removale ctors. */
-
-bool
-ipa_make_function_const (struct cgraph_node *node, bool looping, bool local)
-{
- bool cdtor = false;
-
- if (TREE_READONLY (node->decl)
- && (looping || !DECL_LOOPING_CONST_OR_PURE_P (node->decl)))
- return false;
- warn_function_const (node->decl, !looping);
- if (local && skip_function_for_local_pure_const (node))
- return false;
- if (dump_file)
- fprintf (dump_file, "Function found to be %sconst: %s\n",
- looping ? "looping " : "",
- node->dump_name ());
- if (!local && !looping)
- cdtor = node->call_for_symbol_and_aliases (cdtor_p, NULL, true);
- if (!dbg_cnt (ipa_attr))
- return false;
- if (node->set_const_flag (true, looping))
- {
- if (dump_file)
- fprintf (dump_file,
- "Declaration updated to be %sconst: %s\n",
- looping ? "looping " : "",
- node->dump_name ());
- if (local)
- return true;
- return cdtor;
- }
- return false;
-}
-
-/* Make function const and output warning. If LOCAL is true,
- return true if anything changed. Otherwise return true if
- we may have introduced removale ctors. */
-
-bool
-ipa_make_function_pure (struct cgraph_node *node, bool looping, bool local)
-{
- bool cdtor = false;
-
- if (DECL_PURE_P (node->decl)
- && (looping || !DECL_LOOPING_CONST_OR_PURE_P (node->decl)))
- return false;
- warn_function_pure (node->decl, !looping);
- if (local && skip_function_for_local_pure_const (node))
- return false;
- if (dump_file)
- fprintf (dump_file, "Function found to be %spure: %s\n",
- looping ? "looping " : "",
- node->dump_name ());
- if (!local && !looping)
- cdtor = node->call_for_symbol_and_aliases (cdtor_p, NULL, true);
- if (!dbg_cnt (ipa_attr))
- return false;
- if (node->set_pure_flag (true, looping))
- {
- if (dump_file)
- fprintf (dump_file,
- "Declaration updated to be %spure: %s\n",
- looping ? "looping " : "",
- node->dump_name ());
- if (local)
- return true;
- return cdtor;
- }
- return false;
-}
-
-/* Produce transitive closure over the callgraph and compute pure/const
- attributes. */
-
-static bool
-propagate_pure_const (void)
-{
- struct cgraph_node *node;
- struct cgraph_node *w;
- struct cgraph_node **order =
- XCNEWVEC (struct cgraph_node *, symtab->cgraph_count);
- int order_pos;
- int i;
- struct ipa_dfs_info * w_info;
- bool remove_p = false;
-
- order_pos = ipa_reduced_postorder (order, true,
- ignore_edge_for_pure_const);
- if (dump_file)
- {
- cgraph_node::dump_cgraph (dump_file);
- ipa_print_order (dump_file, "reduced", order, order_pos);
- }
-
- /* Propagate the local information through 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++ )
- {
- enum pure_const_state_e pure_const_state = IPA_CONST;
- bool looping = false;
- int count = 0;
- node = order[i];
-
- if (node->alias)
- continue;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "Starting cycle\n");
-
- /* Find the worst state for any node in the cycle. */
- w = node;
- while (w && pure_const_state != IPA_NEITHER)
- {
- struct cgraph_edge *e;
- struct cgraph_edge *ie;
- int i;
- struct ipa_ref *ref = NULL;
-
- funct_state w_l = funct_state_summaries->get_create (w);
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " Visiting %s state:%s looping %i\n",
- w->dump_name (),
- pure_const_names[w_l->pure_const_state],
- w_l->looping);
-
- /* First merge in function body properties.
- We are safe to pass NULL as FROM and TO because we will take care
- of possible interposition when walking callees. */
- worse_state (&pure_const_state, &looping,
- w_l->pure_const_state, w_l->looping,
- NULL, NULL);
- if (pure_const_state == IPA_NEITHER)
- break;
-
- count++;
-
- /* We consider recursive cycles as possibly infinite.
- This might be relaxed since infinite recursion leads to stack
- overflow. */
- if (count > 1)
- looping = true;
-
- /* Now walk the edges and merge in callee properties. */
- for (e = w->callees; e && pure_const_state != IPA_NEITHER;
- e = e->next_callee)
- {
- enum availability avail;
- struct cgraph_node *y = e->callee->
- function_or_virtual_thunk_symbol (&avail,
- e->caller);
- enum pure_const_state_e edge_state = IPA_CONST;
- bool edge_looping = false;
-
- if (e->recursive_p ())
- looping = true;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file, " Call to %s",
- e->callee->dump_name ());
- }
- if (avail > AVAIL_INTERPOSABLE)
- {
- funct_state y_l = funct_state_summaries->get_create (y);
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- {
- fprintf (dump_file,
- " state:%s looping:%i\n",
- pure_const_names[y_l->pure_const_state],
- y_l->looping);
- }
- if (y_l->pure_const_state > IPA_PURE
- && e->cannot_lead_to_return_p ())
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file,
- " Ignoring side effects"
- " -> pure, looping\n");
- edge_state = IPA_PURE;
- edge_looping = true;
- }
- else
- {
- edge_state = y_l->pure_const_state;
- edge_looping = y_l->looping;
- }
- }
- else if (builtin_safe_for_const_function_p (&edge_looping,
- y->decl))
- edge_state = IPA_CONST;
- else
- state_from_flags (&edge_state, &edge_looping,
- flags_from_decl_or_type (y->decl),
- e->cannot_lead_to_return_p ());
-
- /* Merge the results with what we already know. */
- better_state (&edge_state, &edge_looping,
- w_l->state_previously_known,
- w_l->looping_previously_known);
- worse_state (&pure_const_state, &looping,
- edge_state, edge_looping, e->caller, e->callee);
- if (pure_const_state == IPA_NEITHER)
- break;
- }
-
- /* Now process the indirect call. */
- for (ie = w->indirect_calls;
- ie && pure_const_state != IPA_NEITHER; ie = ie->next_callee)
- {
- enum pure_const_state_e edge_state = IPA_CONST;
- bool edge_looping = false;
-
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " Indirect call");
- state_from_flags (&edge_state, &edge_looping,
- ie->indirect_info->ecf_flags,
- ie->cannot_lead_to_return_p ());
- /* Merge the results with what we already know. */
- better_state (&edge_state, &edge_looping,
- w_l->state_previously_known,
- w_l->looping_previously_known);
- worse_state (&pure_const_state, &looping,
- edge_state, edge_looping, NULL, NULL);
- if (pure_const_state == IPA_NEITHER)
- break;
- }
-
- /* And finally all loads and stores. */
- for (i = 0; w->iterate_reference (i, ref)
- && pure_const_state != IPA_NEITHER; i++)
- {
- enum pure_const_state_e ref_state = IPA_CONST;
- bool ref_looping = false;
- switch (ref->use)
- {
- case IPA_REF_LOAD:
- /* readonly reads are safe. */
- if (TREE_READONLY (ref->referred->decl))
- break;
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " nonreadonly global var read\n");
- ref_state = IPA_PURE;
- break;
- case IPA_REF_STORE:
- if (ref->cannot_lead_to_return ())
- break;
- ref_state = IPA_NEITHER;
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, " global var write\n");
- break;
- case IPA_REF_ADDR:
- break;
- default:
- gcc_unreachable ();
- }
- better_state (&ref_state, &ref_looping,
- w_l->state_previously_known,
- w_l->looping_previously_known);
- worse_state (&pure_const_state, &looping,
- ref_state, ref_looping, NULL, NULL);
- if (pure_const_state == IPA_NEITHER)
- break;
- }
- w_info = (struct ipa_dfs_info *) w->aux;
- w = w_info->next_cycle;
- }
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "Result %s looping %i\n",
- pure_const_names [pure_const_state],
- looping);
-
- /* Find the worst state of can_free for any node in the cycle. */
- bool can_free = false;
- w = node;
- while (w && !can_free)
- {
- struct cgraph_edge *e;
- funct_state w_l = funct_state_summaries->get (w);
-
- if (w_l->can_free
- || w->get_availability () == AVAIL_INTERPOSABLE
- || w->indirect_calls)
- can_free = true;
-
- for (e = w->callees; e && !can_free; e = e->next_callee)
- {
- enum availability avail;
- struct cgraph_node *y = e->callee->
- function_or_virtual_thunk_symbol (&avail,
- e->caller);
-
- if (avail > AVAIL_INTERPOSABLE)
- can_free = funct_state_summaries->get (y)->can_free;
- else
- can_free = 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 = funct_state_summaries->get (w);
- enum pure_const_state_e this_state = pure_const_state;
- bool this_looping = looping;
-
- w_l->can_free = can_free;
- w->nonfreeing_fn = !can_free;
- if (!can_free && dump_file)
- fprintf (dump_file, "Function found not to call free: %s\n",
- w->dump_name ());
-
- if (w_l->state_previously_known != IPA_NEITHER
- && this_state > w_l->state_previously_known)
- {
- if (this_state == IPA_NEITHER)
- this_looping = w_l->looping_previously_known;
- this_state = w_l->state_previously_known;
- }
- if (!this_looping && self_recursive_p (w))
- this_looping = true;
- if (!w_l->looping_previously_known)
- this_looping = false;
-
- /* All nodes within a cycle share the same info. */
- w_l->pure_const_state = this_state;
- w_l->looping = this_looping;
-
- /* Inline clones share declaration with their offline copies;
- do not modify their declarations since the offline copy may
- be different. */
- if (!w->inlined_to)
- switch (this_state)
- {
- case IPA_CONST:
- remove_p |= ipa_make_function_const (w, this_looping, false);
- break;
-
- case IPA_PURE:
- remove_p |= ipa_make_function_pure (w, this_looping, false);
- break;
-
- default:
- break;
- }
- w_info = (struct ipa_dfs_info *) w->aux;
- w = w_info->next_cycle;
- }
- }
-
- ipa_free_postorder_info ();
- free (order);
- return remove_p;
-}
-
-/* Produce transitive closure over the callgraph and compute nothrow
- attributes. */
-
-static void
-propagate_nothrow (void)
-{
- struct cgraph_node *node;
- struct cgraph_node *w;
- struct cgraph_node **order =
- XCNEWVEC (struct cgraph_node *, symtab->cgraph_count);
- int order_pos;
- int i;
- struct ipa_dfs_info * w_info;
-
- order_pos = ipa_reduced_postorder (order, true,
- ignore_edge_for_nothrow);
- if (dump_file)
- {
- cgraph_node::dump_cgraph (dump_file);
- ipa_print_order (dump_file, "reduced for nothrow", order, order_pos);
- }
-
- /* Propagate the local information through 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];
-
- if (node->alias)
- continue;
-
- /* Find the worst state for any node in the cycle. */
- w = node;
- while (w && !can_throw)
- {
- struct cgraph_edge *e, *ie;
-
- if (!TREE_NOTHROW (w->decl))
- {
- funct_state w_l = funct_state_summaries->get_create (w);
-
- if (w_l->can_throw
- || w->get_availability () == AVAIL_INTERPOSABLE)
- can_throw = true;
-
- for (e = w->callees; e && !can_throw; e = e->next_callee)
- {
- enum availability avail;
-
- if (!e->can_throw_external || TREE_NOTHROW (e->callee->decl))
- continue;
-
- struct cgraph_node *y = e->callee->
- function_or_virtual_thunk_symbol (&avail,
- e->caller);
-
- /* We can use info about the callee only if we know it
- cannot be interposed.
- When callee is compiled with non-call exceptions we also
- must check that the declaration is bound to current
- body as other semantically equivalent body may still
- throw. */
- if (avail <= AVAIL_INTERPOSABLE
- || (!TREE_NOTHROW (y->decl)
- && (funct_state_summaries->get_create (y)->can_throw
- || (opt_for_fn (y->decl, flag_non_call_exceptions)
- && !e->callee->binds_to_current_def_p (w)))))
- can_throw = true;
- }
- for (ie = w->indirect_calls; ie && !can_throw;
- ie = ie->next_callee)
- if (ie->can_throw_external
- && !(ie->indirect_info->ecf_flags & ECF_NOTHROW))
- 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 = funct_state_summaries->get_create (w);
- if (!can_throw && !TREE_NOTHROW (w->decl))
- {
- /* Inline clones share declaration with their offline copies;
- do not modify their declarations since the offline copy may
- be different. */
- if (!w->inlined_to)
- {
- w->set_nothrow_flag (true);
- if (dump_file)
- fprintf (dump_file, "Function found to be nothrow: %s\n",
- w->dump_name ());
- }
- }
- 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;
- }
- }
-
- ipa_free_postorder_info ();
- free (order);
-}
-
-/* Debugging function to dump state of malloc lattice. */
-
-DEBUG_FUNCTION
-static void
-dump_malloc_lattice (FILE *dump_file, const char *s)
-{
- if (!dump_file)
- return;
-
- fprintf (dump_file, "\n\nMALLOC LATTICE %s:\n", s);
- cgraph_node *node;
- FOR_EACH_FUNCTION (node)
- {
- funct_state fs = funct_state_summaries->get (node);
- if (fs)
- fprintf (dump_file, "%s: %s\n", node->dump_name (),
- malloc_state_names[fs->malloc_state]);
- }
-}
-
-/* Propagate malloc attribute across the callgraph. */
-
-static void
-propagate_malloc (void)
-{
- cgraph_node *node;
- FOR_EACH_FUNCTION (node)
- {
- if (DECL_IS_MALLOC (node->decl))
- if (!funct_state_summaries->exists (node))
- {
- funct_state fs = funct_state_summaries->get_create (node);
- fs->malloc_state = STATE_MALLOC;
- }
- }
-
- dump_malloc_lattice (dump_file, "Initial");
- struct cgraph_node **order
- = XNEWVEC (struct cgraph_node *, symtab->cgraph_count);
- int order_pos = ipa_reverse_postorder (order);
- bool changed = true;
-
- while (changed)
- {
- changed = false;
- /* Walk in postorder. */
- for (int i = order_pos - 1; i >= 0; --i)
- {
- cgraph_node *node = order[i];
- if (node->alias
- || !node->definition
- || !funct_state_summaries->exists (node))
- continue;
-
- funct_state l = funct_state_summaries->get (node);
-
- /* FIXME: add support for indirect-calls. */
- if (node->indirect_calls)
- {
- l->malloc_state = STATE_MALLOC_BOTTOM;
- continue;
- }
-
- if (node->get_availability () <= AVAIL_INTERPOSABLE)
- {
- l->malloc_state = STATE_MALLOC_BOTTOM;
- continue;
- }
-
- if (l->malloc_state == STATE_MALLOC_BOTTOM)
- continue;
-
- auto_vec<cgraph_node *, 16> callees;
- for (cgraph_edge *cs = node->callees; cs; cs = cs->next_callee)
- {
- ipa_call_summary *es = ipa_call_summaries->get_create (cs);
- if (es && es->is_return_callee_uncaptured)
- callees.safe_push (cs->callee);
- }
-
- malloc_state_e new_state = l->malloc_state;
- for (unsigned j = 0; j < callees.length (); j++)
- {
- cgraph_node *callee = callees[j];
- if (!funct_state_summaries->exists (node))
- {
- new_state = STATE_MALLOC_BOTTOM;
- break;
- }
- malloc_state_e callee_state
- = funct_state_summaries->get_create (callee)->malloc_state;
- if (new_state < callee_state)
- new_state = callee_state;
- }
- if (new_state != l->malloc_state)
- {
- changed = true;
- l->malloc_state = new_state;
- }
- }
- }
-
- FOR_EACH_DEFINED_FUNCTION (node)
- if (funct_state_summaries->exists (node))
- {
- funct_state l = funct_state_summaries->get (node);
- if (!node->alias
- && l->malloc_state == STATE_MALLOC
- && !node->inlined_to
- && !VOID_TYPE_P (TREE_TYPE (TREE_TYPE (node->decl))))
- {
- if (dump_file && (dump_flags & TDF_DETAILS))
- fprintf (dump_file, "Function %s found to be malloc\n",
- node->dump_name ());
-
- bool malloc_decl_p = DECL_IS_MALLOC (node->decl);
- node->set_malloc_flag (true);
- if (!malloc_decl_p && warn_suggest_attribute_malloc)
- warn_function_malloc (node->decl);
- }
- }
-
- dump_malloc_lattice (dump_file, "after propagation");
- ipa_free_postorder_info ();
- free (order);
-}
-
-/* Produce the global information by preforming a transitive closure
- on the local information that was produced by generate_summary. */
-
-unsigned int
-pass_ipa_pure_const::
-execute (function *)
-{
- bool remove_p;
-
- /* Nothrow makes more function to not lead to return and improve
- later analysis. */
- propagate_nothrow ();
- propagate_malloc ();
- remove_p = propagate_pure_const ();
-
- delete funct_state_summaries;
- return remove_p ? TODO_remove_functions : 0;
-}
-
-static bool
-gate_pure_const (void)
-{
- return flag_ipa_pure_const || in_lto_p;
-}
-
-pass_ipa_pure_const::pass_ipa_pure_const(gcc::context *ctxt)
- : ipa_opt_pass_d(pass_data_ipa_pure_const, ctxt,
- pure_const_generate_summary, /* generate_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, /* function_transform_todo_flags_start */
- NULL, /* function_transform */
- NULL), /* variable_transform */
- init_p (false) {}
-
-ipa_opt_pass_d *
-make_pass_ipa_pure_const (gcc::context *ctxt)
-{
- return new pass_ipa_pure_const (ctxt);
-}
-
-/* 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. */
-
-namespace {
-
-const pass_data pass_data_local_pure_const =
-{
- GIMPLE_PASS, /* type */
- "local-pure-const", /* name */
- OPTGROUP_NONE, /* optinfo_flags */
- TV_IPA_PURE_CONST, /* tv_id */
- 0, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- 0, /* todo_flags_finish */
-};
-
-class pass_local_pure_const : public gimple_opt_pass
-{
-public:
- pass_local_pure_const (gcc::context *ctxt)
- : gimple_opt_pass (pass_data_local_pure_const, ctxt)
- {}
-
- /* opt_pass methods: */
- opt_pass * clone () { return new pass_local_pure_const (m_ctxt); }
- virtual bool gate (function *) { return gate_pure_const (); }
- virtual unsigned int execute (function *);
-
-}; // class pass_local_pure_const
-
-unsigned int
-pass_local_pure_const::execute (function *fun)
-{
- bool changed = false;
- funct_state l;
- bool skip;
- struct cgraph_node *node;
-
- node = cgraph_node::get (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);
-
- /* Do NORETURN discovery. */
- if (!skip && !TREE_THIS_VOLATILE (current_function_decl)
- && EDGE_COUNT (EXIT_BLOCK_PTR_FOR_FN (fun)->preds) == 0)
- {
- warn_function_noreturn (fun->decl);
- if (dump_file)
- fprintf (dump_file, "Function found to be noreturn: %s\n",
- current_function_name ());
-
- /* Update declaration and reduce profile to executed once. */
- if (cgraph_node::get (current_function_decl)->set_noreturn_flag (true))
- changed = true;
- if (node->frequency > NODE_FREQUENCY_EXECUTED_ONCE)
- node->frequency = NODE_FREQUENCY_EXECUTED_ONCE;
- }
-
- switch (l->pure_const_state)
- {
- case IPA_CONST:
- changed |= ipa_make_function_const
- (cgraph_node::get (current_function_decl), l->looping, true);
- break;
-
- case IPA_PURE:
- changed |= ipa_make_function_pure
- (cgraph_node::get (current_function_decl), l->looping, true);
- break;
-
- default:
- break;
- }
- if (!l->can_throw && !TREE_NOTHROW (current_function_decl))
- {
- node->set_nothrow_flag (true);
- changed = true;
- if (dump_file)
- fprintf (dump_file, "Function found to be nothrow: %s\n",
- current_function_name ());
- }
-
- if (l->malloc_state == STATE_MALLOC
- && !DECL_IS_MALLOC (current_function_decl))
- {
- node->set_malloc_flag (true);
- if (warn_suggest_attribute_malloc)
- warn_function_malloc (node->decl);
- changed = true;
- if (dump_file)
- fprintf (dump_file, "Function found to be malloc: %s\n",
- node->dump_name ());
- }
-
- free (l);
- if (changed)
- return execute_fixup_cfg ();
- else
- return 0;
-}
-
-} // anon namespace
-
-gimple_opt_pass *
-make_pass_local_pure_const (gcc::context *ctxt)
-{
- return new pass_local_pure_const (ctxt);
-}
-
-/* Emit noreturn warnings. */
-
-namespace {
-
-const pass_data pass_data_warn_function_noreturn =
-{
- GIMPLE_PASS, /* type */
- "*warn_function_noreturn", /* name */
- OPTGROUP_NONE, /* optinfo_flags */
- TV_NONE, /* tv_id */
- PROP_cfg, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- 0, /* todo_flags_finish */
-};
-
-class pass_warn_function_noreturn : public gimple_opt_pass
-{
-public:
- pass_warn_function_noreturn (gcc::context *ctxt)
- : gimple_opt_pass (pass_data_warn_function_noreturn, ctxt)
- {}
-
- /* opt_pass methods: */
- virtual bool gate (function *) { return warn_suggest_attribute_noreturn; }
- virtual unsigned int execute (function *fun)
- {
- if (!TREE_THIS_VOLATILE (current_function_decl)
- && EDGE_COUNT (EXIT_BLOCK_PTR_FOR_FN (fun)->preds) == 0)
- warn_function_noreturn (current_function_decl);
- return 0;
- }
-
-}; // class pass_warn_function_noreturn
-
-} // anon namespace
-
-gimple_opt_pass *
-make_pass_warn_function_noreturn (gcc::context *ctxt)
-{
- return new pass_warn_function_noreturn (ctxt);
-}
-
-/* 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. */
-
-namespace {
-
-const pass_data pass_data_nothrow =
-{
- GIMPLE_PASS, /* type */
- "nothrow", /* name */
- OPTGROUP_NONE, /* optinfo_flags */
- TV_IPA_PURE_CONST, /* tv_id */
- 0, /* properties_required */
- 0, /* properties_provided */
- 0, /* properties_destroyed */
- 0, /* todo_flags_start */
- 0, /* todo_flags_finish */
-};
-
-class pass_nothrow : public gimple_opt_pass
-{
-public:
- pass_nothrow (gcc::context *ctxt)
- : gimple_opt_pass (pass_data_nothrow, ctxt)
- {}
-
- /* opt_pass methods: */
- opt_pass * clone () { return new pass_nothrow (m_ctxt); }
- virtual bool gate (function *) { return optimize; }
- virtual unsigned int execute (function *);
-
-}; // class pass_nothrow
-
-unsigned int
-pass_nothrow::execute (function *)
-{
- struct cgraph_node *node;
- basic_block this_block;
-
- if (TREE_NOTHROW (current_function_decl))
- return 0;
-
- node = cgraph_node::get (current_function_decl);
-
- /* We run during lowering, we cannot really use availability yet. */
- if (cgraph_node::get (current_function_decl)->get_availability ()
- <= AVAIL_INTERPOSABLE)
- {
- if (dump_file)
- fprintf (dump_file, "Function is interposable;"
- " not analyzing.\n");
- return true;
- }
-
- FOR_EACH_BB_FN (this_block, cfun)
- {
- for (gimple_stmt_iterator gsi = gsi_start_bb (this_block);
- !gsi_end_p (gsi);
- gsi_next (&gsi))
- if (stmt_can_throw_external (cfun, gsi_stmt (gsi)))
- {
- if (is_gimple_call (gsi_stmt (gsi)))
- {
- tree callee_t = gimple_call_fndecl (gsi_stmt (gsi));
- if (callee_t && recursive_call_p (current_function_decl,
- callee_t))
- continue;
- }
-
- if (dump_file)
- {
- fprintf (dump_file, "Statement can throw: ");
- print_gimple_stmt (dump_file, gsi_stmt (gsi), 0);
- }
- return 0;
- }
- }
-
- node->set_nothrow_flag (true);
-
- bool cfg_changed = false;
- if (self_recursive_p (node))
- FOR_EACH_BB_FN (this_block, cfun)
- if (gimple *g = last_stmt (this_block))
- if (is_gimple_call (g))
- {
- tree callee_t = gimple_call_fndecl (g);
- if (callee_t
- && recursive_call_p (current_function_decl, callee_t)
- && maybe_clean_eh_stmt (g)
- && gimple_purge_dead_eh_edges (this_block))
- cfg_changed = true;
- }
-
- if (dump_file)
- fprintf (dump_file, "Function found to be nothrow: %s\n",
- current_function_name ());
- return cfg_changed ? TODO_cleanup_cfg : 0;
-}
-
-} // anon namespace
-
-gimple_opt_pass *
-make_pass_nothrow (gcc::context *ctxt)
-{
- return new pass_nothrow (ctxt);
-}