Hi Jeff, The 07/11/2018 20:21, Jeff Law wrote: > On 07/11/2018 05:22 AM, Tamar Christina wrote: > > Hi All, > > > > This patch defines a configure option to allow the setting of the default > > guard size via configure flags when building the target. > > > > The new flag is: > > > > * --with-stack-clash-protection-guard-size=<num> > > > > The value of configured based params are set very early on and allow the > > target to validate or reject the values as it sees fit. > > > > To do this the values for the parameter get set by configure through CPP > > defines. > > In case the back-end wants to know if a value was set or not the original > > default > > value is also passed down as a define. > > > > This allows a target to check if a param was changed by the user at > > configure time. > > > > Bootstrapped Regtested on aarch64-none-linux-gnu, x86_64-pc-linux-gnu and > > no issues. > > Both targets were tested with stack clash on and off by default. > > > > Ok for trunk? > > > > Thanks, > > Tamar > > > > gcc/ > > 2018-07-11 Tamar Christina <tamar.christ...@arm.com> > > > > PR target/86486 > > * configure.ac: Add stack-clash-protection-guard-size. > > * config.in (DEFAULT_STK_CLASH_GUARD_SIZE, STK_CLASH_GUARD_SIZE_DEFAULT, > > STK_CLASH_GUARD_SIZE_MAX, STK_CLASH_GUARD_SIZE_MIN): New. > > * params.def (PARAM_STACK_CLASH_PROTECTION_GUARD_SIZE): Use it. > > * configure: Regenerate. > > * Makefile.in (params.list, params.options): Add include dir for CPP. > > * params-list.h: Include auto-host.h > > * params-options.h: Likewise. > > > Something seems wrong here. > > What's the purpose of including auto-host in params-list and > params-options? It seems like you're putting a property of the target > (guard size) into the wrong place (auto-host.h). >
The reason for this is because there's a test gcc.dg/params/blocksort-part.c that uses these params-options to generate test cases to perform parameter validation. However because now the params.def file can contain a CPP macro these would then fail. CPP is already called to create params-options and params-list so the easiest way to fix this test was just to include auto-host which would get it the values from configure. This test is probably not needed anymore after my second patch series as parameters are validated by the front-end now, so they can never go out of range. > It's also a bit unclear to me why this is necessary at all. Are we > planning to support both the 4k and 64k guards? My goal (once the guard > was configurable) was never for supporting multiple sizes on a target > but instead to allow experimentation to find the right default. > I will get back to you on this one. Thanks, Tamar > Jeff --
