On Fri, Jul 20, 2018 at 1:57 PM, Martin Sebor <mse...@gmail.com> wrote: > On 07/19/2018 04:31 PM, Jeff Law wrote: >> >> On 06/24/2018 03:05 PM, Martin Sebor wrote: >>> >>> Storing integer command line option arguments in type int >>> limits options such as -Wlarger-than= or -Walloca-larger-than >>> to at most INT_MAX (see bug 71905). Larger values wrap around >>> zero. The value zero is considered to disable the option, >>> making it impossible to specify a zero limit. >>> >>> To get around these limitations, the -Walloc-size-larger-than= >>> option accepts a string argument that it then parses itself >>> and interprets as HOST_WIDE_INT. The option also accepts byte >>> size suffixes like KB, MB, GiB, etc. to make it convenient to >>> specify very large limits. >>> >>> The int limitation is obviously less than ideal in a 64-bit >>> world. The treatment of zero as a toggle is just a minor wart. >>> The special treatment to make it work for just a single option >>> makes option handling inconsistent. It should be possible for >>> any option that takes an integer argument to use the same logic. >>> >>> The attached patch enhances GCC option processing to do that. >>> It changes the storage type of option arguments from int to >>> HOST_WIDE_INT and extends the existing (although undocumented) >>> option property Host_Wide_Int to specify wide option arguments. >>> It also introduces the ByteSize property for options for which >>> specifying the byte-size suffix makes sense. >>> >>> To make it possible to consider zero as a meaningful argument >>> value rather than a flag indicating that an option is disabled >>> the patch also adds a CLVC_SIZE enumerator to the cl_var_type >>> enumeration, and modifies how options of the kind are handled. >>> >>> Warning options that take large byte-size arguments can be >>> disabled by specifying a value equal to or greater than >>> HOST_WIDE_INT_M1U. For convenience, aliases in the form of >>> -Wno-xxx-larger-than have been provided for all the affected >>> options. >>> >>> In the patch all the existing -larger-than options are set >>> to PTRDIFF_MAX. This makes them effectively enabled, but >>> because the setting is exceedingly permissive, and because >>> some of the existing warnings are already set to the same >>> value and some other checks detect and reject such exceedingly >>> large values with errors, this change shouldn't noticeably >>> affect what constructs are diagnosed. >>> >>> Although all the options are set to PTRDIFF_MAX, I think it >>> would make sense to consider setting some of them lower, say >>> to PTRDIFF_MAX / 2. I'd like to propose that in a followup >>> patch. >>> >>> To minimize observable changes the -Walloca-larger-than and >>> -Wvla-larger-than warnings required more extensive work to >>> make of the new mechanism because of the "unbounded" argument >>> handling (the warnings trigger for arguments that are not >>> visibly constrained), and because of the zero handling >>> (the warnings also trigger >>> >>> >>> Martin >>> >>> >>> gcc-82063.diff >>> >>> >>> PR middle-end/82063 - issues with arguments enabled by -Wall >>> >>> gcc/ada/ChangeLog: >>> >>> PR middle-end/82063 >>> * gcc-interface/misc.c (gnat_handle_option): Change function >>> argument >>> to HOST_WIDE_INT. >>> >>> gcc/brig/ChangeLog: >>> * brig/brig-lang.c (brig_langhook_handle_option): Change function >>> argument to HOST_WIDE_INT. >>> >>> gcc/c-family/ChangeLog: >>> >>> PR middle-end/82063 >>> * c-common.h (c_common_handle_option): Change function argument >>> to HOST_WIDE_INT. >>> * c-opts.c (c_common_init_options): Same. >>> (c_common_handle_option): Same. Remove special handling of >>> OPT_Walloca_larger_than_ and OPT_Wvla_larger_than_. >>> * c.opt (-Walloc-size-larger-than, -Walloca-larger-than): Change >>> options to take a HOST_WIDE_INT argument and accept a byte-size >>> suffix. Initialize. >>> (-Wvla-larger-than): Same. >>> (-Wno-alloc-size-larger-than, -Wno-alloca-larger-than): New. >>> (-Wno-vla-larger-than): Same. >>> >>> >>> gcc/fortran/ChangeLog: >>> >>> PR middle-end/82063 >>> * gfortran.h (gfc_handle_option): Change function argument >>> to HOST_WIDE_INT. >>> * options.c (gfc_handle_option): Same. >>> >>> gcc/go/ChangeLog: >>> >>> PR middle-end/82063 >>> * go-lang.c (go_langhook_handle_option): Change function argument >>> to HOST_WIDE_INT. >>> >>> gcc/lto/ChangeLog: >>> >>> PR middle-end/82063 >>> * lto-lang.c (lto_handle_option): Change function argument >>> to HOST_WIDE_INT. >>> >>> gcc/testsuite/ChangeLog: >>> >>> PR middle-end/82063 >>> * gcc.dg/Walloc-size-larger-than-16.c: Adjust. >>> * gcc.dg/Walloca-larger-than.c: New test. >>> * gcc.dg/Wframe-larger-than-2.c: New test. >>> * gcc.dg/Wlarger-than3.c: New test. >>> * gcc.dg/Wvla-larger-than-3.c: New test. >>> >>> gcc/ChangeLog: >>> >>> PR middle-end/82063 >>> * builtins.c (expand_builtin_alloca): Adjust. >>> * calls.c (alloc_max_size): Simplify. >>> * cgraphunit.c (cgraph_node::expand): Adjust. >>> * common.opt (larger_than_size, warn_frame_larger_than): Remove >>> variables. >>> (frame_larger_than_size): Same. >>> (-Wframe-larger-than, -Wlarger-than, -Wstack-usage): Change >>> options >>> to take a HOST_WIDE_INT argument and accept a byte-size suffix. >>> Initialize. >>> * doc/invoke.texi (GCC Command Options): Document option >>> arguments. >>> Explain byte-size arguments and suffixes. >>> (-Wvla-larger-than, -Wno-alloc-size-larger-than): Update. >>> (-Wno-alloca-larger-than, -Wno-vla-larger-than): Same. >>> (-Wframe-larger-than, -Wlarger-than, -Wstack-usage): Same. >>> * doc/options.texi (UInteger): Expand. >>> (Host_Wide_Int, ByteSize): Document new properties. >>> * final.c (final_start_function_1): Include sizes in an error >>> message. >>> * function.c (frame_offset_overflow): Same. >>> * gimple-ssa-warn-alloca.c (pass_walloca::gate): Adjust. >>> (alloca_call_type_by_arg): Change function argument to >>> HOST_WIDE_INT. >>> Diagnose unbounded alloca calls only for limits of less than >>> PTRDIFF_MAX. >>> (alloca_call_type): Adjust. Diagnose possibly out-of-bounds >>> alloca >>> calls and VLA size only for limits of less than PTRDIFF_MAX. >>> Same >>> for alloca(0). >>> (pass_walloca::execute): Adjust. Diagnose alloca calls in loops >>> only for limits of less than PTRDIFF_MAX. >>> * langhooks-def.h (lhd_handle_option): Change function argument >>> to HOST_WIDE_INT. >>> * langhooks.c (lhd_handle_option): Same. >>> * langhooks.h (handle_option): Same. >>> * opt-functions.awk (switch_bit_fields): Handle Host_Wide_Int and >>> ByteSize flags. >>> (var_type, var_type_struct): Same. >>> (var_set): Handle ByteSize flag. >>> * optc-gen.awk: Add comments to output to ease debugging. Make >>> use of HOST_WIDE_INT where appropriate. >>> * opts-gen-save.awk: Use %lx to format unsigned long. >>> * opth-gen.awk: Change function argument to HOST_WIDE_INT. >>> * opts-common.c (integral_argument): Return HOST_WIDE_INT and add >>> arguments. Parse bytes-size suffixes. >>> (enum_arg_to_value): Change function argument to HOST_WIDE_INT. >>> (enum_value_to_arg): Same. >>> (decode_cmdline_option): Handle cl_host_wide_int. Adjust. >>> (handle_option): Adjust. >>> (generate_option): Change function argument to HOST_WIDE_INT. >>> (cmdline_handle_error): Adjust. >>> (read_cmdline_option): Change function argument to HOST_WIDE_INT. >>> (set_option): Change function argument to HOST_WIDE_INT. >>> (option_enabled): Handle cl_host_wide_int. >>> (get_option_state): Handle CLVC_SIZE. >>> (control_warning_option): Same. >>> * opts.c (common_handle_option): Change function argument to >>> HOST_WIDE_INT. Remove handling of OPT_Walloca_larger_than_ and >>> OPT_Wvla_larger_than_. >>> * opts.h (enum cl_var_type): Add an enumerator. >>> * stor-layout.c (layout_decl): Print a more meaningful warning. >>> * toplev.c (output_stack_usage): Adjust. >> >> In the doc changes you refer to the -falign-* options. All that stuff >> recently changed. Please make sure your references are still sane given >> those recent changes. > > > As far as I can tell they're still valid. > > >>> + /* When MAX_SIZE is greater than or equal to PTRDIFF_MAX treat >>> + allocations that aren't visibly constrained as OK, otherwise >>> + report them as (potentially) unbonded. */ >> >> s/unbonded/unbounded/ > > > Fixed. > >> >> OK with the nit fixed. IF you need to update the doc changes as a >> result of the -faligned-* changes, those are pre-approved. > > > I had to adjust a few more tests and make a couple of minor > tweaks as I noticed a coupled of test failures that I had > previously missed but the result was didn't show any more > regressions on x86_64. > > Committed in r262910. >
This caused: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86624 This may impact all 32-bit hosts. -- H.J.
