Discussion:
[PATCH] manywarnings: port to 64-bit GCC builds of Emacs
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Paul Eggert
2017-08-04 22:15:59 UTC
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Raw Message
* m4/manywarnings.m4 (gl_MANYWARN_ALL_GCC): Compute max safe
object size rather than hardwiring 2147483647. This is needed to
build GNU Emacs, which has one conditional (and used
only-in-theory) call to malloc with a literal greater than
2147483647.
---
ChangeLog | 9 +++++++++
m4/manywarnings.m4 | 19 +++++++++++++++----
2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 8d2b695b7..caab63ee0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2017-08-04 Paul Eggert <***@cs.ucla.edu>
+
+ manywarnings: port to 64-bit GCC builds of Emacs
+ * m4/manywarnings.m4 (gl_MANYWARN_ALL_GCC): Compute max safe
+ object size rather than hardwiring 2147483647. This is needed to
+ build GNU Emacs, which has one conditional (and used
+ only-in-theory) call to malloc with a literal greater than
+ 2147483647.
+
2017-08-04 Bruno Haible <***@clisp.org>

Relax the license of some modules with no runtime code.
diff --git a/m4/manywarnings.m4 b/m4/manywarnings.m4
index 6cf1be7d3..6a8939b2c 100644
--- a/m4/manywarnings.m4
+++ b/m4/manywarnings.m4
@@ -1,4 +1,4 @@
-# manywarnings.m4 serial 9
+# manywarnings.m4 serial 10
dnl Copyright (C) 2008-2017 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -258,9 +258,20 @@ AC_DEFUN([gl_MANYWARN_ALL_GCC],

# gcc --help=warnings outputs an unusual form for these options; list
# them here so that the above 'comm' command doesn't report a false match.
- # Would prefer "min (PTRDIFF_MAX, SIZE_MAX)", but it must be a literal:
- ptrdiff_max_min=2147483647
- gl_manywarn_set="$gl_manywarn_set -Walloc-size-larger-than=$ptrdiff_max_min"
+ # Would prefer "min (PTRDIFF_MAX, SIZE_MAX)", but it must be a literal
+ # and AC_COMPUTE_INT requires it to fit in a long:
+ AC_MSG_CHECKING([max safe object size])
+ AC_COMPUTE_INT([gl_alloc_max],
+ [(LONG_MAX < PTRDIFF_MAX ? LONG_MAX : PTRDIFF_MAX) < (size_t) -1
+ ? (LONG_MAX < PTRDIFF_MAX ? LONG_MAX : PTRDIFF_MAX)
+ : (size_t) -1],
+ [[#include <limits.h>
+ #include <stddef.h>
+ #include <stdint.h>
+ ]],
+ [gl_alloc_max=2147483647])
+ AC_MSG_RESULT([$gl_alloc_max])
+ gl_manywarn_set="$gl_manywarn_set -Walloc-size-larger-than=$gl_alloc_max"
gl_manywarn_set="$gl_manywarn_set -Warray-bounds=2"
gl_manywarn_set="$gl_manywarn_set -Wformat-overflow=2"
gl_manywarn_set="$gl_manywarn_set -Wformat-truncation=2"
--
2.13.3
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