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authorKirill Smelkov <kirr@mns.spb.ru>2014-03-27 18:22:50 +0400
committerJunio C Hamano <gitster@pobox.com>2014-03-27 11:54:01 -0700
commit61f76a3612db199a9eb9090c2605d8fc35ffc41c (patch)
treefc5e216179e5fd11343f0b59b77b3da354ece5c9 /config.mak.uname
parent12cd81743dc4645ef909b0c38582f5714c9a8ff7 (diff)
downloadgit-61f76a3612db199a9eb9090c2605d8fc35ffc41c.tar.gz
Portable alloca for Git
In the next patch we'll have to use alloca() for performance reasons, but since alloca is non-standardized and is not portable, let's have a trick with compatibility wrappers: 1. at configure time, determine, do we have working alloca() through alloca.h, and define #define HAVE_ALLOCA_H if yes. 2. in code #ifdef HAVE_ALLOCA_H # include <alloca.h> # define xalloca(size) (alloca(size)) # define xalloca_free(p) do {} while(0) #else # define xalloca(size) (xmalloc(size)) # define xalloca_free(p) (free(p)) #endif and use it like func() { p = xalloca(size); ... xalloca_free(p); } This way, for systems, where alloca is available, we'll have optimal on-stack allocations with fast executions. On the other hand, on systems, where alloca is not available, this gracefully fallbacks to xmalloc/free. Both autoconf and config.mak.uname configurations were updated. For autoconf, we are not bothering considering cases, when no alloca.h is available, but alloca() works some other way - its simply alloca.h is available and works or not, everything else is deep legacy. For config.mak.uname, I've tried to make my almost-sure guess for where alloca() is available, but since I only have access to Linux it is the only change I can be sure about myself, with relevant to other changed systems people Cc'ed. NOTE SunOS and Windows had explicit -DHAVE_ALLOCA_H in their configurations. I've changed that to now-common HAVE_ALLOCA_H=YesPlease which should be correct. Cc: Brandon Casey <drafnel@gmail.com> Cc: Marius Storm-Olsen <mstormo@gmail.com> Cc: Johannes Sixt <j6t@kdbg.org> Cc: Johannes Schindelin <Johannes.Schindelin@gmx.de> Cc: Ramsay Jones <ramsay@ramsay1.demon.co.uk> Cc: Gerrit Pape <pape@smarden.org> Cc: Petr Salinger <Petr.Salinger@seznam.cz> Cc: Jonathan Nieder <jrnieder@gmail.com> Acked-by: Thomas Schwinge <thomas@codesourcery.com> (GNU Hurd changes) Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'config.mak.uname')
-rw-r--r--config.mak.uname10
1 files changed, 8 insertions, 2 deletions
diff --git a/config.mak.uname b/config.mak.uname
index 7d31fad241..71602ee9a1 100644
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -28,6 +28,7 @@ ifeq ($(uname_S),OSF1)
NO_NSEC = YesPlease
endif
ifeq ($(uname_S),Linux)
+ HAVE_ALLOCA_H = YesPlease
NO_STRLCPY = YesPlease
NO_MKSTEMPS = YesPlease
HAVE_PATHS_H = YesPlease
@@ -35,6 +36,7 @@ ifeq ($(uname_S),Linux)
HAVE_DEV_TTY = YesPlease
endif
ifeq ($(uname_S),GNU/kFreeBSD)
+ HAVE_ALLOCA_H = YesPlease
NO_STRLCPY = YesPlease
NO_MKSTEMPS = YesPlease
HAVE_PATHS_H = YesPlease
@@ -103,6 +105,7 @@ ifeq ($(uname_S),SunOS)
NEEDS_NSL = YesPlease
SHELL_PATH = /bin/bash
SANE_TOOL_PATH = /usr/xpg6/bin:/usr/xpg4/bin
+ HAVE_ALLOCA_H = YesPlease
NO_STRCASESTR = YesPlease
NO_MEMMEM = YesPlease
NO_MKDTEMP = YesPlease
@@ -146,7 +149,7 @@ ifeq ($(uname_S),SunOS)
endif
INSTALL = /usr/ucb/install
TAR = gtar
- BASIC_CFLAGS += -D__EXTENSIONS__ -D__sun__ -DHAVE_ALLOCA_H
+ BASIC_CFLAGS += -D__EXTENSIONS__ -D__sun__
endif
ifeq ($(uname_O),Cygwin)
ifeq ($(shell expr "$(uname_R)" : '1\.[1-6]\.'),4)
@@ -166,6 +169,7 @@ ifeq ($(uname_O),Cygwin)
else
NO_REGEX = UnfortunatelyYes
endif
+ HAVE_ALLOCA_H = YesPlease
NEEDS_LIBICONV = YesPlease
NO_FAST_WORKING_DIRECTORY = UnfortunatelyYes
NO_ST_BLOCKS_IN_STRUCT_STAT = YesPlease
@@ -239,6 +243,7 @@ ifeq ($(uname_S),AIX)
endif
ifeq ($(uname_S),GNU)
# GNU/Hurd
+ HAVE_ALLOCA_H = YesPlease
NO_STRLCPY = YesPlease
NO_MKSTEMPS = YesPlease
HAVE_PATHS_H = YesPlease
@@ -316,6 +321,7 @@ endif
ifeq ($(uname_S),Windows)
GIT_VERSION := $(GIT_VERSION).MSVC
pathsep = ;
+ HAVE_ALLOCA_H = YesPlease
NO_PREAD = YesPlease
NEEDS_CRYPTO_WITH_SSL = YesPlease
NO_LIBGEN_H = YesPlease
@@ -363,7 +369,7 @@ ifeq ($(uname_S),Windows)
COMPAT_OBJS = compat/msvc.o compat/winansi.o \
compat/win32/pthread.o compat/win32/syslog.o \
compat/win32/dirent.o
- COMPAT_CFLAGS = -D__USE_MINGW_ACCESS -DNOGDI -DHAVE_STRING_H -DHAVE_ALLOCA_H -Icompat -Icompat/regex -Icompat/win32 -DSTRIP_EXTENSION=\".exe\"
+ COMPAT_CFLAGS = -D__USE_MINGW_ACCESS -DNOGDI -DHAVE_STRING_H -Icompat -Icompat/regex -Icompat/win32 -DSTRIP_EXTENSION=\".exe\"
BASIC_LDFLAGS = -IGNORE:4217 -IGNORE:4049 -NOLOGO -SUBSYSTEM:CONSOLE -NODEFAULTLIB:MSVCRT.lib
EXTLIBS = user32.lib advapi32.lib shell32.lib wininet.lib ws2_32.lib
PTHREAD_LIBS =