[PATCH v2] RISC-V: Add --march=help
Hau Hsu
hau.hsu@sifive.com
Tue Jan 30 12:32:17 GMT 2024
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 <research_trasio@irq.a4lg.com> 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 <hau.hsu@sifive.com>
>> ---
>> 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 <hau.hsu@sifive.com>
>> +
>> + * 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 <nickc@redhat.com>
>>
>> * 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;
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