Hi Tsukasa, Indeed this idea is from Clang. Let me see if I can have another implementation based on your suggestions. Thanks for your quick reply :). Best, Hau Hsu Software Engineer hau.hsu@sifive.com > Tsukasa OI 於 2024年1月30日 下午4:43 寫道： > > Hi Hau, > > I'm not yet ready to come back to Binutils development (because I > haven't finished writing my research paper) but I'd like to comment. > > While your idea seems great at first glance, I would never like to see > "help" handling in the riscv_parse_subset function because many other > functions call it (some calls this function with an argument retrieved > from an assembly / object file and your design seems vulnerable from > adversarial files e.g. when disassembling files with unknown origin). > > Besides that, I think that's not a bad idea (quite rare to see in the > GNU toolchain, though). > > IMHO, the right place to put "help" handling (at least, its entry point) > is the md_parse_option function in gas/config/tc-riscv.c. Exiting > successfully from here is rare but at least cris and kvx does so for > help-like options. > > Thanks, > Tsukasa > > On 2024/01/30 15:36, Hau Hsu wrote: >> Use --march=help to print all supported extensions and versions. >> >> This patch assumes that the supported extensions with the same versions >> are listed together. >> >> For example >> static struct riscv_supported_ext riscv_supported_std_ext[] = >> { >> ... >> {"i", ISA_SPEC_CLASS_20191213, 2, 1, 0 }, >> {"i", ISA_SPEC_CLASS_20190608, 2, 1, 0 }, >> {"i", ISA_SPEC_CLASS_2P2, 2, 0, 0 }, >> ... >> }; >> >> For "i" extension, 2.1.0 with different spec class are listed together. >> This patch records the previous printed extension and version. If the >> current extension and version are the same as the previous one, skip >> printing. >> >> Here is part of the output of `as -march=help`: >> >> All available -march extensions for RISC-V: >> e 1.9 >> i 2.1, 2.0 >> m 2.0 >> a 2.1, 2.0 >> f 2.2, 2.0 >> d 2.2, 2.0 >> q 2.2, 2.0 >> c 2.0 >> v 1.0 >> h 1.0 >> zicbom 1.0 >> zicbop 1.0 >> >> Signed-off-by: Hau Hsu >> --- >> bfd/ChangeLog | 9 ++++++ >> bfd/elfxx-riscv.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 81 insertions(+) >> >> diff --git a/bfd/ChangeLog b/bfd/ChangeLog >> index 97d0c585a56..0807a2e0bcb 100644 >> --- a/bfd/ChangeLog >> +++ b/bfd/ChangeLog >> @@ -1,3 +1,12 @@ >> +2024-01-17 Hau Hsu >> + >> + * elfxx-riscv.c (riscv_parse_subset): Parse 'help' keyword to print >> + available extension and versions. >> + (riscv_print_extensions): New function. >> + (riscv_same_extension_version): New function. >> + (riscv_same_extension_diff_version): New function. >> + (riscv_valid_ext): New function. >> + >> 2024-01-15 Nick Clifton >> >> * 2.42 branch point. >> diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c >> index 9a121b47121..bb394a589b1 100644 >> --- a/bfd/elfxx-riscv.c >> +++ b/bfd/elfxx-riscv.c >> @@ -2051,6 +2051,71 @@ riscv_set_default_arch (riscv_parse_subset_t *rps) >> } >> } >> >> +static >> +bool riscv_same_extension_version( >> + const struct riscv_supported_ext* ext1, >> + const struct riscv_supported_ext* ext2) >> +{ >> + return (strcmp(ext1->name, ext2->name) == 0 >> + && ext1->major_version == ext2->major_version >> + && ext1->minor_version == ext2->minor_version); >> +} >> + >> +static >> +bool riscv_same_extension_diff_version( >> + const struct riscv_supported_ext* ext1, >> + const struct riscv_supported_ext* ext2) >> +{ >> + return (strcmp(ext1->name, ext2->name) == 0 >> + && !(ext1->major_version == ext2->major_version >> + && ext1->minor_version == ext2->minor_version)); >> +} >> + >> +static >> +bool riscv_valid_ext(const struct riscv_supported_ext *ext) >> +{ >> + return (ext->isa_spec_class != ISA_SPEC_CLASS_NONE >> + && ext->major_version != RISCV_UNKNOWN_VERSION >> + && ext->minor_version != RISCV_UNKNOWN_VERSION); >> +} >> + >> +static >> +void riscv_print_extensions(void) >> +{ >> + /* Record the previous pritned extension. >> + Print the current one if they are not the same. */ >> + const struct riscv_supported_ext *cur = NULL, *prev = NULL; >> + >> + int i, j; >> + printf ("All available -march extensions for RISC-V:"); >> + for (i = 0; riscv_all_supported_ext[i] != NULL; i++) >> + { >> + const struct riscv_supported_ext *exts = riscv_all_supported_ext[i]; >> + prev = NULL; >> + for (j = 0; exts[j].name != NULL; j++) >> + { >> + cur = &exts[j]; >> + if (!riscv_valid_ext (cur)) >> + continue; >> + >> + if (prev && riscv_same_extension_version (prev, cur)) >> + continue; >> + >> + if (!prev || !riscv_same_extension_diff_version (prev, cur)) >> + { >> + printf("\n\t%-40s%d.%d", cur->name, cur->major_version, cur->minor_version); >> + prev = &exts[j]; >> + } >> + else >> + { >> + printf(", %d.%d", cur->major_version, cur->minor_version); >> + prev = &exts[j]; >> + } >> + } >> + } >> + printf ("\n"); >> +} >> + >> /* Function for parsing ISA string. >> >> Return Value: >> @@ -2089,6 +2154,13 @@ riscv_parse_subset (riscv_parse_subset_t *rps, >> } >> >> p = arch; >> + /* List all avaiable archs. */ >> + if (strcmp (p, "help") == 0) >> + { >> + riscv_print_extensions(); >> + exit (EXIT_SUCCESS); >> + } >> + >> if (startswith (p, "rv32")) >> { >> *rps->xlen = 32;