diff options
Diffstat (limited to 'SConstruct')
| -rw-r--r-- | SConstruct | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/SConstruct b/SConstruct index 70f32cbd94f..9e7640ecb6b 100644 --- a/SConstruct +++ b/SConstruct @@ -3238,6 +3238,63 @@ def doConfigure(myenv): # ask each module to configure itself and the build environment. moduleconfig.configure_modules(mongo_modules, conf) + if env['TARGET_ARCH'] == "ppc64le": + # This checks for an altivec optimization we use in full text search. + # Different versions of gcc appear to put output bytes in different + # parts of the output vector produced by vec_vbpermq. This configure + # check looks to see which format the compiler produces. + # + # NOTE: This breaks cross compiles, as it relies on checking runtime functionality for the + # environment we're in. A flag to choose the index, or the possibility that we don't have + # multiple versions to support (after a compiler upgrade) could solve the problem if we + # eventually need them. + def CheckAltivecVbpermqOutput(context, index): + test_body = """ + #include <altivec.h> + #include <cstring> + #include <cstdint> + #include <cstdlib> + + int main() {{ + using Native = __vector signed char; + const size_t size = sizeof(Native); + const Native bits = {{ 120, 112, 104, 96, 88, 80, 72, 64, 56, 48, 40, 32, 24, 16, 8, 0 }}; + + uint8_t inputBuf[size]; + std::memset(inputBuf, 0xFF, sizeof(inputBuf)); + + for (size_t offset = 0; offset <= size; offset++) {{ + Native vec = vec_vsx_ld(0, reinterpret_cast<const Native*>(inputBuf)); + + uint64_t mask = vec_extract(vec_vbpermq(vec, bits), {0}); + + size_t initialZeros = (mask == 0 ? size : __builtin_ctzll(mask)); + if (initialZeros != offset) {{ + return 1; + }} + + if (offset < size) {{ + inputBuf[offset] = 0; // Add an initial 0 for the next loop. + }} + }} + + return 0; + }} + """.format(index) + + context.Message('Checking for vec_vbperm output in index {0}... '.format(index)) + ret = context.TryRun(textwrap.dedent(test_body), ".cpp") + context.Result(ret[0]) + return ret[0] + + conf.AddTest('CheckAltivecVbpermqOutput', CheckAltivecVbpermqOutput) + + outputIndex = next((idx for idx in [0,1] if conf.CheckAltivecVbpermqOutput(idx)), None) + if outputIndex is not None: + conf.env.SetConfigHeaderDefine("MONGO_CONFIG_ALTIVEC_VEC_VBPERMQ_OUTPUT_INDEX", outputIndex) + else: + myenv.ConfError("Running on ppc64le, but can't find a correct vec_vbpermq output index. Compiler or platform not supported") + return conf.Finish() env = doConfigure( env ) |