Message338335
'configure' cache values are set to pessimistic defaults when cross-compiling. One of the most significant, ac_cv_computed_gotos, is set to 'no' in that case. When ac_cv_computed_gotos is set to 'yes' on platforms that support it, it brings a 15-20 % gain in performance. To know if a platform supports computed goto when not cross-compiling, a C test program is built and run using the AC_RUN_IFELSE autoconf macro in configure.ac.
Most platforms provide a way to transfer a file and to run a remote shell, whether it is using ssh or by other means (Android has the 'adb' swiss-knife tool). This is a proposal to extend the AC_RUN_IFELSE macro to also copy the executable locally when cross-compiling. A script uploads it later on the platform, target of the cross-compilation, runs it on this platform, collects its exit status and sets the corresponding cache value accordingly in a config.site file. A second run of 'configure', with the CONFIG_SITE environment variable set to the *absolute* path of this config.site file, allows configuring the build with the correct cache values for this platform. |
|
Date |
User |
Action |
Args |
2019-03-19 09:31:36 | xdegaye | set | recipients:
+ xdegaye, Alex.Willmer |
2019-03-19 09:31:36 | xdegaye | set | messageid: <1552987896.08.0.0930536102698.issue36361@roundup.psfhosted.org> |
2019-03-19 09:31:36 | xdegaye | link | issue36361 messages |
2019-03-19 09:31:35 | xdegaye | create | |
|