invoke.texi (-Wsuggest-attribute=const, [...]): Document.
2010-04-27 Manuel López-Ibáñez <manu@gcc.gnu.org> Jan Hubicka <hubicka@ucw.cz> * doc/invoke.texi (-Wsuggest-attribute=const, -Wsuggest-attribute=pure): Document. * ipa-pure-const.c: Include toplev.h, intl.h and opts.h. (function_always_visible_to_compiler_p, suggest_attribute, warn_function_pure, warn_function_const): New functions. (check_call): Improve debug info. (analyze_function): Do not check availability. (add_new_function): Check availability. (propagate): Output warnings. (skip_function_for_local_pure_const): New function. (local_pure_const): Use it; output warnings. * common.opt (Wsuggest-attribute=const, Wsuggest-attribute=pure): New. testsuite/ * gcc.dg/pure-2.c: New testcase. * gcc.dg/const-1.c: New testcase. Co-Authored-By: Jan Hubicka <hubicka@ucw.cz> From-SVN: r158803
This commit is contained in:
Manuel López-Ibáñez
parent
ea8b8aa005
commit
5dc16b1952
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@ -1,3 +1,21 @@
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2010-04-27 Manuel López-Ibáñez <manu@gcc.gnu.org>
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Jan Hubicka <hubicka@ucw.cz>
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* doc/invoke.texi (-Wsuggest-attribute=const,
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-Wsuggest-attribute=pure): Document.
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* ipa-pure-const.c: Include toplev.h, intl.h and opts.h.
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(function_always_visible_to_compiler_p,
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suggest_attribute, warn_function_pure, warn_function_const):
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New functions.
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(check_call): Improve debug info.
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(analyze_function): Do not check availability.
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(add_new_function): Check availability.
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(propagate): Output warnings.
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(skip_function_for_local_pure_const): New function.
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(local_pure_const): Use it; output warnings.
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* common.opt (Wsuggest-attribute=const,
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Wsuggest-attribute=pure): New.
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2010-04-27 Jakub Jelinek <jakub@redhat.com>
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* dwarf2out.c (def_cfa_1): After DW_CFA_def_cfa_expression
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@ -180,6 +180,14 @@ Wstrict-overflow=
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Common Joined UInteger Var(warn_strict_overflow) Init(-1) Warning
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Warn about optimizations that assume that signed overflow is undefined
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Wsuggest-attribute=const
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Common Var(warn_suggest_attribute_const) Warning
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Warn about functions which might be candidates for __attribute__((const))
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Wsuggest-attribute=pure
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Common Var(warn_suggest_attribute_pure) Warning
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Warn about functions which might be candidates for __attribute__((pure))
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Wswitch
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Common Var(warn_switch) Warning
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Warn about enumerated switches, with no default, missing a case
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@ -257,6 +257,7 @@ Objective-C and Objective-C++ Dialects}.
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-Wsign-compare -Wsign-conversion -Wstack-protector @gol
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-Wstrict-aliasing -Wstrict-aliasing=n @gol
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-Wstrict-overflow -Wstrict-overflow=@var{n} @gol
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-Wsuggest-attribute=@r{[}const@r{|}pure@r{]} @gol
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-Wswitch -Wswitch-default -Wswitch-enum -Wsync-nand @gol
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-Wsystem-headers -Wtrigraphs -Wtype-limits -Wundef -Wuninitialized @gol
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-Wunknown-pragmas -Wno-pragmas @gol
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@ -3621,11 +3622,36 @@ comparisons, so this warning level will give a very large number of
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false positives.
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@end table
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@item -Wsuggest-attribute=@r{[}const@r{|}pure@r{]}
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@opindex Wsuggest-attribute=
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@opindex Wno-suggest-attribute=
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Warn for cases where adding an attribute may be beneficial. The
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attributes currently supported are listed below.
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@table @gcctabopt
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@item -Wsuggest-attribute=pure
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@itemx -Wsuggest-attribute=const
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@opindex Wsuggest-attribute=pure
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@opindex Wno-suggest-attribute=pure
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@opindex Wsuggest-attribute=const
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@opindex Wno-suggest-attribute=const
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Warn about functions which might be candidates for attributes
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@code{pure} or @code{const}. The compiler only warns for functions
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visible in other compilation units or if it cannot prove that the
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function returns normally. A function returns normally if it doesn't
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contain an infinite loop nor returns abnormally by throwing, calling
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@code{abort()} or trapping. This analysis requires option
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@option{-fipa-pure-const}, which is enabled by default at @option{-O}
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and higher. Higher optimization levels improve the accuracy of the
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analysis.
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@end table
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@item -Warray-bounds
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@opindex Wno-array-bounds
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@opindex Warray-bounds
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This option is only active when @option{-ftree-vrp} is active
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(default for -O2 and above). It warns about subscripts to arrays
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(default for @option{-O2} and above). It warns about subscripts to arrays
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that are always out of bounds. This warning is enabled by @option{-Wall}.
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@item -Wno-div-by-zero
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@ -49,12 +49,15 @@ along with GCC; see the file COPYING3. If not see
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#include "output.h"
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#include "flags.h"
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#include "timevar.h"
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#include "toplev.h"
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#include "diagnostic.h"
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#include "langhooks.h"
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#include "target.h"
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#include "lto-streamer.h"
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#include "cfgloop.h"
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#include "tree-scalar-evolution.h"
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#include "intl.h"
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#include "opts.h"
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static struct pointer_set_t *visited_nodes;
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@ -106,6 +109,71 @@ static struct cgraph_node_hook_list *function_insertion_hook_holder;
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static struct cgraph_2node_hook_list *node_duplication_hook_holder;
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static struct cgraph_node_hook_list *node_removal_hook_holder;
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/* Try to guess if function body will always be visible to compiler
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when compiling the call and whether compiler will be able
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to propagate the information by itself. */
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static bool
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function_always_visible_to_compiler_p (tree decl)
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{
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return (!TREE_PUBLIC (decl) || DECL_DECLARED_INLINE_P (decl));
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}
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/* Emit suggestion about attribute ATTRIB_NAME for DECL. KNOWN_FINITE
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is true if the function is known to be finite. The diagnostic is
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controlled by OPTION. WARNED_ABOUT is a pointer_set unique for
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OPTION, this function may initialize it and it is always returned
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by the function. */
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static struct pointer_set_t *
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suggest_attribute (int option, tree decl, bool known_finite,
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struct pointer_set_t *warned_about,
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const char * attrib_name)
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{
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if (!option_enabled (option))
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return warned_about;
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if (TREE_THIS_VOLATILE (decl)
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|| (known_finite && function_always_visible_to_compiler_p (decl)))
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return warned_about;
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if (!warned_about)
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warned_about = pointer_set_create ();
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if (pointer_set_contains (warned_about, decl))
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return warned_about;
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pointer_set_insert (warned_about, decl);
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warning_at (DECL_SOURCE_LOCATION (decl),
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option,
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known_finite
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? _("function might be candidate for attribute %<%s%>")
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: _("function might be candidate for attribute %<%s%>"
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" if it is known to return normally"), attrib_name);
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return warned_about;
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}
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/* Emit suggestion about __attribute_((pure)) for DECL. KNOWN_FINITE
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is true if the function is known to be finite. */
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static void
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warn_function_pure (tree decl, bool known_finite)
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{
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static struct pointer_set_t *warned_about;
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warned_about
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= suggest_attribute (OPT_Wsuggest_attribute_pure, decl,
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known_finite, warned_about, "pure");
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}
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/* Emit suggestion about __attribute_((const)) for DECL. KNOWN_FINITE
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is true if the function is known to be finite. */
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static void
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warn_function_const (tree decl, bool known_finite)
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{
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static struct pointer_set_t *warned_about;
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warned_about
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= suggest_attribute (OPT_Wsuggest_attribute_const, decl,
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known_finite, warned_about, "const");
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}
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/* Init the function state. */
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static void
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@ -325,7 +393,11 @@ check_call (funct_state local, gimple call, bool ipa)
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/* When not in IPA mode, we can still handle self recursion. */
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if (!ipa && callee_t == current_function_decl)
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local->looping = true;
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{
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if (dump_file)
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fprintf (dump_file, " Recursive call can loop.\n");
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local->looping = true;
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}
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/* Either calle is unknown or we are doing local analysis.
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Look to see if there are any bits available for the callee (such as by
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declaration or because it is builtin) and process solely on the basis of
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@ -353,12 +425,20 @@ check_call (funct_state local, gimple call, bool ipa)
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if (flags & ECF_CONST)
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{
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if (callee_t && DECL_LOOPING_CONST_OR_PURE_P (callee_t))
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local->looping = true;
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{
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if (dump_file)
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fprintf (dump_file, " calls looping pure.\n");
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local->looping = true;
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}
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}
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else if (flags & ECF_PURE)
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{
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if (callee_t && DECL_LOOPING_CONST_OR_PURE_P (callee_t))
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local->looping = true;
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{
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if (dump_file)
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fprintf (dump_file, " calls looping const.\n");
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local->looping = true;
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}
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if (dump_file)
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fprintf (dump_file, " pure function call in not const\n");
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if (local->pure_const_state == IPA_CONST)
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@ -604,7 +684,8 @@ add_new_function (struct cgraph_node *node, void *data ATTRIBUTE_UNUSED)
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since all we would be interested in are the addressof
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operations. */
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visited_nodes = pointer_set_create ();
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set_function_state (node, analyze_function (node, true));
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if (cgraph_function_body_availability (node) > AVAIL_OVERWRITABLE)
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set_function_state (node, analyze_function (node, true));
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pointer_set_destroy (visited_nodes);
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visited_nodes = NULL;
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}
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@ -938,19 +1019,27 @@ propagate (void)
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switch (this_state)
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{
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case IPA_CONST:
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if (!TREE_READONLY (w->decl) && dump_file)
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fprintf (dump_file, "Function found to be %sconst: %s\n",
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this_looping ? "looping " : "",
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cgraph_node_name (w));
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if (!TREE_READONLY (w->decl))
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{
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warn_function_const (w->decl, !this_looping);
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if (dump_file)
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fprintf (dump_file, "Function found to be %sconst: %s\n",
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this_looping ? "looping " : "",
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cgraph_node_name (w));
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}
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cgraph_set_readonly_flag (w, true);
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cgraph_set_looping_const_or_pure_flag (w, this_looping);
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break;
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case IPA_PURE:
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if (!DECL_PURE_P (w->decl) && dump_file)
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fprintf (dump_file, "Function found to be %spure: %s\n",
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this_looping ? "looping " : "",
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cgraph_node_name (w));
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if (!DECL_PURE_P (w->decl))
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{
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warn_function_pure (w->decl, !this_looping);
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if (dump_file)
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fprintf (dump_file, "Function found to be %spure: %s\n",
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this_looping ? "looping " : "",
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cgraph_node_name (w));
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}
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cgraph_set_pure_flag (w, true);
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cgraph_set_looping_const_or_pure_flag (w, this_looping);
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break;
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@ -1103,6 +1192,29 @@ struct ipa_opt_pass_d pass_ipa_pure_const =
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NULL /* variable_transform */
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};
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/* Return true if function should be skipped for local pure const analysis. */
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static bool
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skip_function_for_local_pure_const (struct cgraph_node *node)
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{
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/* Because we do not schedule pass_fixup_cfg over whole program after early optimizations
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we must not promote functions that are called by already processed functions. */
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if (function_called_by_processed_nodes_p ())
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{
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if (dump_file)
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fprintf (dump_file, "Function called in recursive cycle; ignoring\n");
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return true;
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}
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if (cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE)
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{
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if (dump_file)
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fprintf (dump_file, "Function is not available or overwrittable; not analyzing.\n");
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return true;
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}
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return false;
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}
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/* Simple local pass for pure const discovery reusing the analysis from
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ipa_pure_const. This pass is effective when executed together with
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other optimization passes in early optimization pass queue. */
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@ -1112,25 +1224,15 @@ local_pure_const (void)
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{
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bool changed = false;
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funct_state l;
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bool skip;
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struct cgraph_node *node;
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/* Because we do not schedule pass_fixup_cfg over whole program after early optimizations
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we must not promote functions that are called by already processed functions. */
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if (function_called_by_processed_nodes_p ())
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{
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if (dump_file)
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fprintf (dump_file, "Function called in recursive cycle; ignoring\n");
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return 0;
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}
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node = cgraph_node (current_function_decl);
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if (cgraph_function_body_availability (node) <= AVAIL_OVERWRITABLE)
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{
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if (dump_file)
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fprintf (dump_file, "Function has wrong visibility; ignoring\n");
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return 0;
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}
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skip = skip_function_for_local_pure_const (node);
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if (!warn_suggest_attribute_const
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&& !warn_suggest_attribute_pure
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&& skip)
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return 0;
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l = analyze_function (node, false);
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switch (l->pure_const_state)
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@ -1138,9 +1240,13 @@ local_pure_const (void)
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case IPA_CONST:
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if (!TREE_READONLY (current_function_decl))
|
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{
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cgraph_set_readonly_flag (node, true);
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cgraph_set_looping_const_or_pure_flag (node, l->looping);
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changed = true;
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warn_function_const (current_function_decl, !l->looping);
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if (!skip)
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{
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cgraph_set_readonly_flag (node, true);
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cgraph_set_looping_const_or_pure_flag (node, l->looping);
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changed = true;
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}
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if (dump_file)
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fprintf (dump_file, "Function found to be %sconst: %s\n",
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l->looping ? "looping " : "",
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@ -1150,8 +1256,11 @@ local_pure_const (void)
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else if (DECL_LOOPING_CONST_OR_PURE_P (current_function_decl)
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&& !l->looping)
|
||||
{
|
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cgraph_set_looping_const_or_pure_flag (node, false);
|
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changed = true;
|
||||
if (!skip)
|
||||
{
|
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cgraph_set_looping_const_or_pure_flag (node, false);
|
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changed = true;
|
||||
}
|
||||
if (dump_file)
|
||||
fprintf (dump_file, "Function found to be non-looping: %s\n",
|
||||
lang_hooks.decl_printable_name (current_function_decl,
|
||||
|
|
@ -1160,11 +1269,15 @@ local_pure_const (void)
|
|||
break;
|
||||
|
||||
case IPA_PURE:
|
||||
if (!TREE_READONLY (current_function_decl))
|
||||
if (!DECL_PURE_P (current_function_decl))
|
||||
{
|
||||
cgraph_set_pure_flag (node, true);
|
||||
cgraph_set_looping_const_or_pure_flag (node, l->looping);
|
||||
changed = true;
|
||||
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 " : "",
|
||||
|
|
@ -1174,8 +1287,11 @@ local_pure_const (void)
|
|||
else if (DECL_LOOPING_CONST_OR_PURE_P (current_function_decl)
|
||||
&& !l->looping)
|
||||
{
|
||||
cgraph_set_looping_const_or_pure_flag (node, false);
|
||||
changed = true;
|
||||
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,
|
||||
|
|
|
|||
|
|
@ -1,3 +1,9 @@
|
|||
2010-04-27 Manuel López-Ibáñez <manu@gcc.gnu.org>
|
||||
Jan Hubicka <hubicka@ucw.cz>
|
||||
|
||||
* gcc.dg/pure-2.c: New testcase.
|
||||
* gcc.dg/const-1.c: New testcase.
|
||||
|
||||
2010-04-27 Jason Merrill <jason@redhat.com>
|
||||
|
||||
* g++.dg/cpp0x/lambda/lambda-ice1.C: New.
|
||||
|
|
|
|||
|
|
@ -0,0 +1,57 @@
|
|||
/* { dg-do compile } */
|
||||
/* { dg-options "-O2 -Wsuggest-attribute=const" } */
|
||||
|
||||
extern int extern_const(int a) __attribute__ ((const));
|
||||
|
||||
/* Trivial. */
|
||||
int
|
||||
foo1(int a) /* { dg-bogus "normally" "detect const candidate" } */
|
||||
{ /* { dg-warning "const" "detect const candidate" { target *-*-* } "8" } */
|
||||
return extern_const (a);
|
||||
}
|
||||
|
||||
/* Loops known to be normally and extern const calls should be safe. */
|
||||
|
||||
int __attribute__ ((noinline))
|
||||
foo2(int n) /* { dg-bogus "normally" "detect const candidate" } */
|
||||
{ /* { dg-warning "const" "detect const candidate" { target *-*-* } "16" } */
|
||||
int ret = 0;
|
||||
int i;
|
||||
for (i=0; i<n; i++)
|
||||
ret+=extern_const (i);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* No warning here; we can work it by ourselves. */
|
||||
static int __attribute__ ((noinline))
|
||||
foo2b(int n)
|
||||
{
|
||||
int ret = 0;
|
||||
int i;
|
||||
for (i=0; i<n; i++)
|
||||
ret+=extern_const (i);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* Unbounded loops are not safe. */
|
||||
static int __attribute__ ((noinline))
|
||||
foo3(int n) /* { dg-warning "const\[^\n\]* normally" "detect const candidate" } */
|
||||
{
|
||||
int ret = 0;
|
||||
int i;
|
||||
for (i=0; extern_const (i+n); n++)
|
||||
ret+=extern_const (i);
|
||||
return ret;
|
||||
}
|
||||
|
||||
int
|
||||
foo4(int n) /* { dg-warning "const\[^\n\]* normally" "detect const candidate" } */
|
||||
{
|
||||
return foo3(n) + foo2b(n);
|
||||
}
|
||||
|
||||
int
|
||||
foo5(int n) /* { dg-bogus "normally" "detect const candidate" } */
|
||||
{ /* { dg-warning "const" "detect const candidate" { target *-*-* } "54" } */
|
||||
return foo2(n);
|
||||
}
|
||||
|
|
@ -0,0 +1,57 @@
|
|||
/* { dg-do compile } */
|
||||
/* { dg-options "-O2 -Wsuggest-attribute=pure" } */
|
||||
|
||||
extern int extern_const(int a) __attribute__ ((pure));
|
||||
extern int v;
|
||||
|
||||
/* Trivial. */
|
||||
int
|
||||
foo1(int a) /* { dg-bogus "normally" "detect pure candidate" } */
|
||||
{ /* { dg-warning "pure" "detect pure candidate" { target *-*-* } "9" } */
|
||||
return v;
|
||||
}
|
||||
|
||||
/* Loops known to be normally and extern const calls should be safe. */
|
||||
int __attribute__ ((noinline))
|
||||
foo2(int n) /* { dg-bogus "normally" "detect pure candidate" } */
|
||||
{ /* { dg-warning "pure" "detect pure candidate" { target *-*-* } "16" } */
|
||||
int ret = 0;
|
||||
int i;
|
||||
for (i=0; i<n; i++)
|
||||
ret+=extern_const (i);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* No warning here; we can work it by ourselves. */
|
||||
static int __attribute__ ((noinline))
|
||||
foo2b(int n)
|
||||
{
|
||||
int ret = 0;
|
||||
int i;
|
||||
for (i=0; i<n; i++)
|
||||
ret+=extern_const (i);
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* Unbounded loops are not safe. */
|
||||
static int __attribute__ ((noinline))
|
||||
foo3(int n) /* { dg-warning "pure\[^\n\]* normally" "detect pure candidate" } */
|
||||
{
|
||||
int ret = 0;
|
||||
int i;
|
||||
for (i=0; extern_const (i+n); n++)
|
||||
ret+=extern_const (i);
|
||||
return ret;
|
||||
}
|
||||
|
||||
int
|
||||
foo4(int n) /* { dg-warning "pure\[^\n\]* normally" "detect pure candidate" } */
|
||||
{
|
||||
return foo3(n) + foo2b(n);
|
||||
}
|
||||
|
||||
int
|
||||
foo5(int n) /* { dg-bogus "normally" "detect pure candidate" } */
|
||||
{ /* { dg-warning "pure" "detect pure candidate" { target *-*-* } "54" } */
|
||||
return foo2(n);
|
||||
}
|
||||
Loading…
Reference in New Issue