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| author | Andrew Morrow <acm@mongodb.com> | 2014-05-14 10:41:00 -0400 |
|---|---|---|
| committer | Andrew Morrow <acm@mongodb.com> | 2014-05-17 15:46:27 -0400 |
| commit | 1134c0d1fc3dcbde6a457ecd55de1697d7a13f97 (patch) | |
| tree | 0fa755f11b9ac1cf7ea42678ba1c1b8cdca34dca /SConstruct | |
| parent | 9df8f46db0152921264a6bd235cfd0fd655bf1bc (diff) | |
| download | mongo-1134c0d1fc3dcbde6a457ecd55de1697d7a13f97.tar.gz | |
SERVER-6018 Use gcc __sync primitives if they are available and useable
Diffstat (limited to 'SConstruct')
| -rw-r--r-- | SConstruct | 45 |
1 files changed, 40 insertions, 5 deletions
diff --git a/SConstruct b/SConstruct index 8b0ef8a3ad5..06616dc1c54 100644 --- a/SConstruct +++ b/SConstruct @@ -1441,17 +1441,52 @@ def doConfigure(myenv): return 0; } """ - context.Message('Checking for gcc atomic builtins... ') + context.Message('Checking for gcc __atomic builtins... ') ret = context.TryLink(textwrap.dedent(test_body), '.cpp') context.Result(ret) return ret + + def CheckGCCSyncBuiltins(context): + test_body = """ + int main(int argc, char **argv) { + int a = 0; + return __sync_fetch_and_add(&a, 1); + } + + // + // Figure out if we are using gcc older than 4.2 to target 32-bit x86. If so, error out + // even if we were able to compile the __sync statement, due to + // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=40693 + // + #if defined(__i386__) + #if !defined(__clang__) + #if defined(__GNUC__) && (__GNUC__ == 4) && (__GNUC_MINOR__ < 2) + #error "Refusing to use __sync in 32-bit mode with gcc older than 4.2" + #endif + #endif + #endif + """ + + context.Message('Checking for useable __sync builtins... ') + ret = context.TryLink(textwrap.dedent(test_body), '.cpp') + context.Result(ret) + return ret + conf = Configure(myenv, help=False, custom_tests = { 'CheckGCCAtomicBuiltins': CheckGCCAtomicBuiltins, + 'CheckGCCSyncBuiltins': CheckGCCSyncBuiltins, }) - haveGCCAtomicBuiltins = conf.CheckGCCAtomicBuiltins() - conf.Finish() - if haveGCCAtomicBuiltins: - conf.env.Append(CPPDEFINES=["HAVE_GCC_ATOMIC_BUILTINS"]) + + # Prefer the __atomic builtins. If we don't have those, try for __sync. Otherwise + # atomic_intrinsics.h will try to fall back to the hand-rolled assembly implementations + # in atomic_intrinsics_gcc_intel for x86 platforms. + if conf.CheckGCCAtomicBuiltins(): + conf.env.Append(CPPDEFINES=["MONGO_HAVE_GCC_ATOMIC_BUILTINS"]) + else: + if conf.CheckGCCSyncBuiltins(): + conf.env.Append(CPPDEFINES=["MONGO_HAVE_GCC_SYNC_BUILTINS"]) + + myenv = conf.Finish() conf = Configure(myenv) libdeps.setup_conftests(conf) |