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In <https://sourceware.org/ml/libc-alpha/2014-11/msg00326.html>, Roland requested internal macros for use of "#pragma GCC diagnostic". This patch adds such macros and uses them to disable -Wformat warnings for some code testing GNU scanf %as where GCC expects C99 scanf %a (several other stdio tests currently use -Wno-format to disable warnings). Limitations in GCC's diagnostic pragmas require separate macros before and after the code generating the warnings, rather than a single macro taking that code as an argument. The macros are named DIAG_*_NEEDS_COMMENT to emphasise to reviewers the need for a comment accompanying any use of them (such comments may however just appear once for several uses of the macros for the same issue in the same file). I put a GCC version in the arguments to DIAG_IGNORE_NEEDS_COMMENT, as that seems something useful to grep for when obsoleting support for an old GCC version and needing to decide if warning-disabling code is still relevant. These macros should be usable for replacing existing -Wno-* use in makefiles (as also suggested by Roland), though I have no plans to work on that (only on use of the macros in cases where warnings are currently present that need disabling to use -Werror). Tested for x86_64. * include/libc-internal.h (DIAG_PUSH_NEEDS_COMMENT): New macro. (DIAG_POP_NEEDS_COMMENT): Likewise. (_DIAG_STR1): Likewise. (_DIAG_STR): Likewise. (DIAG_IGNORE_NEEDS_COMMENT): Likewise. * stdio-common/bug21.c: Include <libc-internal.h>. (do_test): Disable -Wformat around call to sscanf. * stdio-common/scanf14.c: Include <libc-internal.h>. (main): Disable -Wformat around some calls to scanf functions.
111 lines
4.5 KiB
C
111 lines
4.5 KiB
C
/* This file contains a number of internal prototype declarations that
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don't fit anywhere else. */
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#ifndef _LIBC_INTERNAL
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# define _LIBC_INTERNAL 1
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#include <hp-timing.h>
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/* Initialize the `__libc_enable_secure' flag. */
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extern void __libc_init_secure (void);
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/* This function will be called from _init in init-first.c. */
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extern void __libc_global_ctors (void);
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/* Discover the tick frequency of the machine if something goes wrong,
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we return 0, an impossible hertz. */
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extern int __profile_frequency (void);
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libc_hidden_proto (__profile_frequency)
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/* Hooks for the instrumenting functions. */
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extern void __cyg_profile_func_enter (void *this_fn, void *call_site);
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extern void __cyg_profile_func_exit (void *this_fn, void *call_site);
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/* Get frequency of the system processor. */
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extern hp_timing_t __get_clockfreq (void);
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/* Free all allocated resources. */
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extern void __libc_freeres (void);
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libc_hidden_proto (__libc_freeres)
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/* Free resources stored in thread-local variables on thread exit. */
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extern void __libc_thread_freeres (void);
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/* Define and initialize `__progname' et. al. */
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extern void __init_misc (int, char **, char **);
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/* 1 if 'type' is a pointer type, 0 otherwise. */
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# define __pointer_type(type) (__builtin_classify_type ((type) 0) == 5)
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/* __intptr_t if P is true, or T if P is false. */
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# define __integer_if_pointer_type_sub(T, P) \
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__typeof__ (*(0 ? (__typeof__ (0 ? (T *) 0 : (void *) (P))) 0 \
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: (__typeof__ (0 ? (__intptr_t *) 0 : (void *) (!(P)))) 0))
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/* __intptr_t if EXPR has a pointer type, or the type of EXPR otherwise. */
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# define __integer_if_pointer_type(expr) \
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__integer_if_pointer_type_sub(__typeof__ ((__typeof__ (expr)) 0), \
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__pointer_type (__typeof__ (expr)))
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/* Cast an integer or a pointer VAL to integer with proper type. */
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# define cast_to_integer(val) ((__integer_if_pointer_type (val)) (val))
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/* Align a value by rounding down to closest size.
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e.g. Using size of 4096, we get this behavior:
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{4095, 4096, 4097} = {0, 4096, 4096}. */
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#define ALIGN_DOWN(base, size) ((base) & -((__typeof__ (base)) (size)))
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/* Align a value by rounding up to closest size.
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e.g. Using size of 4096, we get this behavior:
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{4095, 4096, 4097} = {4096, 4096, 8192}.
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Note: The size argument has side effects (expanded multiple times). */
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#define ALIGN_UP(base, size) ALIGN_DOWN ((base) + (size) - 1, (size))
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/* Same as ALIGN_DOWN(), but automatically casts when base is a pointer. */
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#define PTR_ALIGN_DOWN(base, size) \
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((__typeof__ (base)) ALIGN_DOWN ((uintptr_t) (base), (size)))
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/* Same as ALIGN_UP(), but automatically casts when base is a pointer. */
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#define PTR_ALIGN_UP(base, size) \
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((__typeof__ (base)) ALIGN_UP ((uintptr_t) (base), (size)))
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/* Ignore the value of an expression when a cast to void does not
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suffice (in particular, for a call to a function declared with
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attribute warn_unused_result). */
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#define ignore_value(x) \
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({ __typeof__ (x) __ignored_value = (x); (void) __ignored_value; })
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/* The macros to control diagnostics are structured like this, rather
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than a single macro that both pushes and pops diagnostic state and
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takes the affected code as an argument, because the GCC pragmas
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work by disabling the diagnostic for a range of source locations
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and do not work when all the pragmas and the affected code are in a
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single macro expansion. */
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/* Push diagnostic state. */
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#define DIAG_PUSH_NEEDS_COMMENT _Pragma ("GCC diagnostic push")
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/* Pop diagnostic state. */
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#define DIAG_POP_NEEDS_COMMENT _Pragma ("GCC diagnostic pop")
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#define _DIAG_STR1(s) #s
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#define _DIAG_STR(s) _DIAG_STR1(s)
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/* Ignore the diagnostic OPTION. VERSION is the most recent GCC
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version for which the diagnostic has been confirmed to appear in
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the absence of the pragma (in the form MAJOR.MINOR for GCC 4.x,
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just MAJOR for GCC 5 and later). Uses of this pragma should be
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reviewed when the GCC version given is no longer supported for
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building glibc; the version number should always be on the same
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source line as the macro name, so such uses can be found with grep.
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Uses should come with a comment giving more details of the
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diagnostic, and an architecture on which it is seen if possibly
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optimization-related and not in architecture-specific code. This
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macro should only be used if the diagnostic seems hard to fix (for
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example, optimization-related false positives). */
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#define DIAG_IGNORE_NEEDS_COMMENT(version, option) \
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_Pragma (_DIAG_STR (GCC diagnostic ignored option))
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#endif /* _LIBC_INTERNAL */
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