thanks for catching that, seem like we only check for the linux path :) Edwin Lu <e...@rivosinc.com> 於 2024年7月23日 週二 02:45 寫道：
> Hi Kito, > > > On 7/22/2024 8:19 AM, Kito Cheng wrote: > > Corresponding implementation in compiler-rt already merged in LLVM > > side, so I plan to merge this into trunk tomorrow if no strong > > objections. > > > > NOTE: This has been tested with clang/llvm within our internal CI. > > > On Mon, Jul 22, 2024 at 10:16 PM Kito Cheng <kito.ch...@sifive.com> > wrote: > >> > >> This provides a common abstraction layer to probe the available > extensions at > >> run-time. These functions can be used to implement function > multi-versioning or > >> to detect available extensions. > >> > >> The advantages of providing this abstraction layer are: > >> - Easy to port to other new platforms. > >> - Easier to maintain in GCC for function multi-versioning. > >> - For example, maintaining platform-dependent code in C code/libgcc > is much > >> easier than maintaining it in GCC by creating GIMPLEs... > >> > >> This API is intended to provide the capability to query minimal common > available extensions on the system. > >> > >> Proposal in riscv-c-api-doc: > https://github.com/riscv-non-isa/riscv-c-api-doc/pull/74 > >> > >> Full function multi-versioning implementation will come later. We are > posting > >> this first because we intend to backport it to the GCC 14 branch to > unblock > >> LLVM 19 to use this with GCC 14.2, rather than waiting for GCC 15. > >> > >> Changes since v2: > >> - Prevent it initialize more than once. > >> > >> Changes since v1: > >> - Fix the format. > >> - Prevented race conditions by introducing a local variable to avoid > load/store > >> operations during the computation of the feature bit. > >> > >> libgcc/ChangeLog: > >> > >> * config/riscv/feature_bits.c: New. > >> * config/riscv/t-elf (LIB2ADD): Add feature_bits.c. > >> --- > >> libgcc/config/riscv/feature_bits.c | 313 +++++++++++++++++++++++++++++ > >> libgcc/config/riscv/t-elf | 1 + > >> 2 files changed, 314 insertions(+) > >> create mode 100644 libgcc/config/riscv/feature_bits.c > >> > >> diff --git a/libgcc/config/riscv/feature_bits.c > b/libgcc/config/riscv/feature_bits.c > >> new file mode 100644 > >> index 00000000000..cce4fbfa6be > >> --- /dev/null > >> +++ b/libgcc/config/riscv/feature_bits.c > >> @@ -0,0 +1,313 @@ > >> + > >> +void __init_riscv_feature_bits () > >> +{ > >> + if (__init) > >> + return; > >> + > >> +#ifdef __linux > >> + __init_riscv_features_bits_linux (); > >> +#else > >> + /* Unsupported, just initlizaed that into all zeros. */ > >> + __riscv_feature_bits.length = 0 > > I don't know enough about this to be able to comment on the patch > itself. There's just a missing semicolon here which slipped its way into > the v3 patch which would cause errors when trying to build on non-linux > targets. > > ../../../../../../gcc/libgcc/config/riscv/feature_bits.c:307:34: error: > expected ';' before '__riscv_vendor_feature_bits' > 307 | __riscv_feature_bits.length = 0 > | ^ > | ; > 308 | __riscv_vendor_feature_bits.length = 0; > | ~~~~~~~~~~~~~~~~~~~~~~~~~~~ > make[5]: *** [../../../../../../gcc/libgcc/static-object.mk:17: > feature_bits.o] Error 1 > > > >> + __riscv_vendor_feature_bits.length = 0; > >> + __riscv_vendor_feature_bits.vendorID = 0; > >> +#endif > >> + > >> + __init = 1; > >> +} > > Edwin > > > >
