* [PATCH 1/2] Port better to GCC under macOS
@ 2019-10-23 20:34 Paul Eggert
2019-10-23 20:34 ` [PATCH 2/2] nstrftime: speed up integer overflow checking Paul Eggert
0 siblings, 1 reply; 2+ messages in thread
From: Paul Eggert @ 2019-10-23 20:34 UTC (permalink / raw)
To: bug-gnulib; +Cc: Paul Eggert
Work around macOS header that has ‘#define __has_builtin(x) 0’
when compiled by GCC. Apple really, really doesn’t want you to
use GCC, apparently. Rroblem reported by Akim Demaille in:
https://lists.gnu.org/r/bug-bison/2019-10/msg00071.html
The fix is to not trust __has_builtin when being compiled by
recent-enough GCC.
* lib/intprops.h (__has_builtin)
(_GL_HAS___builtin_add_overflow, _GL_TEMPDEF___has_builtin):
* lib/verify.h (__has_builtin, _GL_HAS___builtin_unreachable)
(_GL_HAS___builtin_trap, _GL_TEMPDEF___has_builtin):
Remove. All uses removed.
* lib/intprops.h (_GL_HAS_BUILTIN_ADD_OVERFLOW): Use __has_builtin
directly, if defined and if not newer GCC.
* lib/verify.h (_GL_HAS_BUILTIN_TRAP, _GL_HAS_BUILTIN_UNREACHABLE):
New macro, that use __has_builtin directly, if defined and if
not newer GCC.
(assume): Use them.
---
ChangeLog | 21 +++++++++++++++++++++
lib/intprops.h | 22 +++-------------------
lib/verify.h | 37 ++++++++++++++++++-------------------
3 files changed, 42 insertions(+), 38 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index fc438f503..103befc64 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,24 @@
+2019-10-23 Paul Eggert <eggert@cs.ucla.edu>
+
+ Port better to GCC under macOS
+ Work around macOS header that has ‘#define __has_builtin(x) 0’
+ when compiled by GCC. Apple really, really doesn’t want you to
+ use GCC, apparently. Rroblem reported by Akim Demaille in:
+ https://lists.gnu.org/r/bug-bison/2019-10/msg00071.html
+ The fix is to not trust __has_builtin when being compiled by
+ recent-enough GCC.
+ * lib/intprops.h (__has_builtin)
+ (_GL_HAS___builtin_add_overflow, _GL_TEMPDEF___has_builtin):
+ * lib/verify.h (__has_builtin, _GL_HAS___builtin_unreachable)
+ (_GL_HAS___builtin_trap, _GL_TEMPDEF___has_builtin):
+ Remove. All uses removed.
+ * lib/intprops.h (_GL_HAS_BUILTIN_ADD_OVERFLOW): Use __has_builtin
+ directly, if defined and if not newer GCC.
+ * lib/verify.h (_GL_HAS_BUILTIN_TRAP, _GL_HAS_BUILTIN_UNREACHABLE):
+ New macro, that use __has_builtin directly, if defined and if
+ not newer GCC.
+ (assume): Use them.
+
2019-10-22 Akim Demaille <akim@lrde.epita.fr>
maintainer-makefile: update rule for argmatch.
diff --git a/lib/intprops.h b/lib/intprops.h
index ffd737028..bc7e950a0 100644
--- a/lib/intprops.h
+++ b/lib/intprops.h
@@ -22,18 +22,6 @@
#include <limits.h>
-/* If the compiler lacks __has_builtin, define it well enough for this
- source file only. */
-#ifndef __has_builtin
-# define __has_builtin(x) _GL_HAS_##x
-# if 5 <= __GNUC__ && !defined __ICC
-# define _GL_HAS___builtin_add_overflow 1
-# else
-# define _GL_HAS___builtin_add_overflow 0
-# endif
-# define _GL_TEMPDEF___has_builtin
-#endif
-
/* Return a value with the common real type of E and V and the value of V.
Do not evaluate E. */
#define _GL_INT_CONVERT(e, v) ((1 ? 0 : (e)) + (v))
@@ -234,8 +222,10 @@
/* True if __builtin_add_overflow (A, B, P) and __builtin_sub_overflow
(A, B, P) work when P is non-null. */
-#if __has_builtin (__builtin_add_overflow)
+#if 5 <= __GNUC__ && !defined __ICC
# define _GL_HAS_BUILTIN_ADD_OVERFLOW 1
+#elif defined __has_builtin
+# define _GL_HAS_BUILTIN_ADD_OVERFLOW __has_builtin (__builtin_add_overflow)
#else
# define _GL_HAS_BUILTIN_ADD_OVERFLOW 0
#endif
@@ -586,10 +576,4 @@
: (tmin) / (a) < (b)) \
: (tmax) / (b) < (a)))
-#ifdef _GL_TEMPDEF___has_builtin
-# undef __has_builtin
-# undef _GL_HAS___builtin_add_overflow
-# undef _GL_TEMPDEF___has_builtin
-#endif
-
#endif /* _GL_INTPROPS_H */
diff --git a/lib/verify.h b/lib/verify.h
index 06e975ebf..a58005c39 100644
--- a/lib/verify.h
+++ b/lib/verify.h
@@ -56,16 +56,6 @@
# undef _Static_assert
#endif
-/* If the compiler lacks __has_builtin, define it well enough for this
- source file only. */
-#ifndef __has_builtin
-# define __has_builtin(x) _GL_HAS_##x
-# define _GL_HAS___builtin_unreachable (4 < __GNUC__ + (5 <= __GNUC_MINOR__))
-# define _GL_HAS___builtin_trap \
- (3 < __GNUC__ + (3 < __GNUC_MINOR__ + (4 <= __GNUC_PATCHLEVEL__)))
-# define _GL_TEMPDEF___has_builtin
-#endif
-
/* Each of these macros verifies that its argument R is nonzero. To
be portable, R should be an integer constant expression. Unlike
assert (R), there is no run-time overhead.
@@ -243,6 +233,22 @@ template <int w>
/* @assert.h omit start@ */
+#if 3 < __GNUC__ + (3 < __GNUC_MINOR__ + (4 <= __GNUC_PATCHLEVEL__))
+# define _GL_HAS_BUILTIN_TRAP 1
+#elif defined __has_builtin
+# define _GL_HAS_BUILTIN_TRAP __has_builtin (__builtin_trap)
+#else
+# define _GL_HAS_BUILTIN_TRAP 0
+#endif
+
+#if 4 < __GNUC__ + (5 <= __GNUC_MINOR__)
+# define _GL_HAS_BUILTIN_UNREACHABLE 1
+#elif defined __has_builtin
+# define _GL_HAS_BUILTIN_UNREACHABLE __has_builtin (__builtin_unreachable)
+#else
+# define _GL_HAS_BUILTIN_UNREACHABLE 0
+#endif
+
/* Each of these macros verifies that its argument R is nonzero. To
be portable, R should be an integer constant expression. Unlike
assert (R), there is no run-time overhead.
@@ -276,11 +282,11 @@ template <int w>
can suffer if R uses hard-to-optimize features such as function
calls not inlined by the compiler. */
-#if __has_builtin (__builtin_unreachable)
+#if _GL_HAS_BUILTIN_UNREACHABLE
# define assume(R) ((R) ? (void) 0 : __builtin_unreachable ())
#elif 1200 <= _MSC_VER
# define assume(R) __assume (R)
-#elif (defined GCC_LINT || defined lint) && __has_builtin (__builtin_trap)
+#elif (defined GCC_LINT || defined lint) && _GL_HAS_BUILTIN_TRAP
/* Doing it this way helps various packages when configured with
--enable-gcc-warnings, which compiles with -Dlint. It's nicer
when 'assume' silences warnings even with older GCCs. */
@@ -290,13 +296,6 @@ template <int w>
# define assume(R) ((R) ? (void) 0 : /*NOTREACHED*/ (void) 0)
#endif
-#ifdef _GL_TEMPDEF___has_builtin
-# undef __has_builtin
-# undef _GL_HAS___builtin_unreachable
-# undef _GL_HAS___builtin_trap
-# undef _GL_TEMPDEF___has_builtin
-#endif
-
/* @assert.h omit end@ */
#endif
--
2.21.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH 2/2] nstrftime: speed up integer overflow checking
2019-10-23 20:34 [PATCH 1/2] Port better to GCC under macOS Paul Eggert
@ 2019-10-23 20:34 ` Paul Eggert
0 siblings, 0 replies; 2+ messages in thread
From: Paul Eggert @ 2019-10-23 20:34 UTC (permalink / raw)
To: bug-gnulib; +Cc: Paul Eggert
* lib/nstrftime.c: Include intprops.h.
(INT_STRLEN_BOUND): Remove, as we can use intprops.h’s defn.
(__strftime_internal): Use INT_MULTIPLY_WRAPV and INT_ADD_WRAPV
instead of doing it by hand.
* modules/nstrftime (Depends-on): Add intprops.
---
ChangeLog | 7 +++++++
lib/nstrftime.c | 19 ++++---------------
modules/nstrftime | 1 +
3 files changed, 12 insertions(+), 15 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 103befc64..804294150 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2019-10-23 Paul Eggert <eggert@cs.ucla.edu>
+ nstrftime: speed up integer overflow checking
+ * lib/nstrftime.c: Include intprops.h.
+ (INT_STRLEN_BOUND): Remove, as we can use intprops.h’s defn.
+ (__strftime_internal): Use INT_MULTIPLY_WRAPV and INT_ADD_WRAPV
+ instead of doing it by hand.
+ * modules/nstrftime (Depends-on): Add intprops.
+
Port better to GCC under macOS
Work around macOS header that has ‘#define __has_builtin(x) 0’
when compiled by GCC. Apple really, really doesn’t want you to
diff --git a/lib/nstrftime.c b/lib/nstrftime.c
index 01db02bfe..11ad00b10 100644
--- a/lib/nstrftime.c
+++ b/lib/nstrftime.c
@@ -68,6 +68,8 @@ extern char *tzname[];
#include <string.h>
#include <stdbool.h>
+#include <intprops.h>
+
#ifndef FALLTHROUGH
# if __GNUC__ < 7
# define FALLTHROUGH ((void) 0)
@@ -113,13 +115,6 @@ extern char *tzname[];
? (a) >> (b) \
: (a) / (1 << (b)) - ((a) % (1 << (b)) < 0))
-/* Bound on length of the string representing an integer type or expression T.
- Subtract 1 for the sign bit if t is signed; log10 (2.0) < 146/485;
- add 1 for integer division truncation; add 1 more for a minus sign
- if needed. */
-#define INT_STRLEN_BOUND(t) \
- ((sizeof (t) * CHAR_BIT - 1) * 146 / 485 + 2)
-
#define TM_YEAR_BASE 1900
#ifndef __isleap
@@ -704,15 +699,9 @@ __strftime_internal (STREAM_OR_CHAR_T *s, STRFTIME_ARG (size_t maxsize)
width = 0;
do
{
- if (width > INT_MAX / 10
- || (width == INT_MAX / 10 && *f - L_('0') > INT_MAX % 10))
- /* Avoid overflow. */
+ if (INT_MULTIPLY_WRAPV (width, 10, &width)
+ || INT_ADD_WRAPV (width, *f - L_('0'), &width))
width = INT_MAX;
- else
- {
- width *= 10;
- width += *f - L_('0');
- }
++f;
}
while (ISDIGIT (*f));
diff --git a/modules/nstrftime b/modules/nstrftime
index b559b5e20..a1ce1b33f 100644
--- a/modules/nstrftime
+++ b/modules/nstrftime
@@ -9,6 +9,7 @@ m4/nstrftime.m4
Depends-on:
extensions
+intprops
stdbool
time_rz
--
2.21.0
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