On Mon, Aug 19, 2019 at 08:15:38PM -0700, Nathan Chancellor wrote: > On Mon, Aug 19, 2019 at 04:19:31AM -0500, Segher Boessenkool wrote: > > On Sun, Aug 18, 2019 at 12:13:21PM -0700, Nathan Chancellor wrote: > > > When building pseries_defconfig, building vdso32 errors out: > > > > > > error: unknown target ABI 'elfv1' > > > > > > Commit 4dc831aa8813 ("powerpc: Fix compiling a BE kernel with a > > > powerpc64le toolchain") added these flags to fix building GCC but > > > clang is multitargeted and does not need these flags. The ABI is > > > properly set based on the target triple, which is derived from > > > CROSS_COMPILE. > > > > You mean that LLVM does not *allow* you to select a different ABI, or > > different ABI options, you always have to use the default. (Everything > > else you say is true for GCC as well). > > I need to improve the wording of the commit message as it is really that > clang does not allow a different ABI to be selected for 32-bit PowerPC, > as the setABI function is not overridden and it defaults to false.
> GCC appears to just silently ignores this flag (I think it is the > SUBSUBTARGET_OVERRIDE_OPTIONS macro in gcc/config/rs6000/linux64.h). What flag? -mabi=elfv[12]? (Only irrelevant things are ever ignored; otherwise, please do a bug report). > It can be changed for 64-bit PowerPC it seems but it doesn't need to be > with clang because everything is set properly internally (I'll find a > better way to clearly word that as I am sure I'm not quite getting that > subtlety right). You can have elfv2 on BE, and e.g. the sysv ABI on LE. Neither of those is tested a lot. > > (-mabi= does not set a "target ABI", fwiw, it is more subtle; please see > > the documentation. Unless LLVM is incompatible in that respect as well?) > > Are you referring to the error message? Yup. > I suppose I could file an LLVM > bug report on that but that message applies to all of the '-mabi=' > options, which may refer to a target ABI. That depends on what you call "an ABI", I guess. You can call any ABI variant a separate ABI: you'll have to rebuild all of userland. You can also says ELFv1 and ELFv2 are pretty much the same thing, which is true as well. The way -mabi= is defined is the latter: '-mabi=ABI-TYPE' Extend the current ABI with a particular extension, or remove such extension. Valid values are 'altivec', 'no-altivec', 'ibmlongdouble', 'ieeelongdouble', 'elfv1', 'elfv2'. Segher