From 468ad10f502837ed00f9e91ed16b9eb180adff4c Mon Sep 17 00:00:00 2001 From: Andreas Sandberg Date: Mon, 18 Mar 2013 10:57:26 +0100 Subject: scons: Avoid malloc/free compiler optimization when using tcmalloc According to the tcmalloc readme, the recommended way of compiling applications that make use of tcmalloc is to disable compiler optimizations that make assumptions about malloc and friends. This changeset adds the necessary compiler flags for both gcc and clang. From the tcmalloc readme: "NOTE: When compiling with programs with gcc, that you plan to link with libtcmalloc, it's safest to pass in the flags -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-free when compiling." --- SConstruct | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/SConstruct b/SConstruct index 2be0a6767..b175cb491 100755 --- a/SConstruct +++ b/SConstruct @@ -505,6 +505,12 @@ Export('MakeAction') main['LTO_CCFLAGS'] = [] main['LTO_LDFLAGS'] = [] +# According to the readme, tcmalloc works best if the compiler doesn't +# assume that we're using the builtin malloc and friends. These flags +# are compiler-specific, so we need to set them after we detect which +# compiler we're using. +main['TCMALLOC_CCFLAGS'] = [] + CXX_version = readCommand([main['CXX'],'--version'], exception=False) CXX_V = readCommand([main['CXX'],'-V'], exception=False) @@ -581,6 +587,9 @@ if main['GCC']: main['LTO_LDFLAGS'] = ['-flto=%d' % GetOption('num_jobs'), '-fuse-linker-plugin'] + main.Append(TCMALLOC_CCFLAGS=['-fno-builtin-malloc', '-fno-builtin-calloc', + '-fno-builtin-realloc', '-fno-builtin-free']) + elif main['CLANG']: # Check for a supported version of clang, >= 2.9 is needed to # support similar features as gcc 4.4. See @@ -607,6 +616,8 @@ elif main['CLANG']: '-Wno-parentheses', '-Wno-self-assign']) + main.Append(TCMALLOC_CCFLAGS=['-fno-builtin']) + # On Mac OS X/Darwin we need to also use libc++ (part of XCode) as # opposed to libstdc++ to make the transition from TR1 to # C++11. See http://libcxx.llvm.org. However, clang has chosen a @@ -914,7 +925,9 @@ have_posix_clock = \ conf.CheckLibWithHeader('rt', 'time.h', 'C', 'clock_nanosleep(0,0,NULL,NULL);') -if not conf.CheckLib('tcmalloc_minimal'): +if conf.CheckLib('tcmalloc_minimal'): + main.Append(CCFLAGS=main['TCMALLOC_CCFLAGS']) +else: print termcap.Yellow + termcap.Bold + \ "You can get a 12% performance improvement by installing tcmalloc "\ "(libgoogle-perftools-dev package on Ubuntu or RedHat)." + \ -- cgit v1.2.3