[PATCH 2/2] RISC-V: Check for conflicting extensions when the linker merges arch attributes
Nelson Chu
nelson.chu@sifive.com
Tue Jul 7 01:26:44 GMT 2026
Oh, okay, I see the case: inputs with 'c' and inputs with 'd' will need zcd
after merging. Looks reasonable to call riscv_parse_add_implicit_subsets
for merged string, too.
Thanks
Nelson
On Tue, Jul 7, 2026 at 9:19 AM Nelson Chu <nelson.chu@sifive.com> wrote:
>
>
> On Mon, Jul 6, 2026 at 7:46 PM Ethan Y. C. Liang <ycl669@andestech.com>
> wrote:
>
>> The linker validates the arch of each input when parsing it, but never
>> checks the merged arch as a whole, so conflicting extensions could
>> silently slip through. The merge can even imply extensions that
>> neither input implies alone, e.g. `c' from one input and `d' from
>> another imply `zcd', which conflicts with `zcmp'.
>>
>> After merging the input archs, add the implicit extensions to the
>> merged arch, then run the conflict checks on it and reject the merge
>> if any conflict is found. Add tests for such merges.
>> ---
>> bfd/elfxx-riscv.c | 8 ++++++++
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01.d | 5 +++++
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01.l | 2 ++
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01a.s | 1 +
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01b.s | 1 +
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02.d | 5 +++++
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02.l | 2 ++
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02a.s | 1 +
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02b.s | 1 +
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03.d | 5 +++++
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03.l | 2 ++
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03a.s | 1 +
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03b.s | 1 +
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04.d | 5 +++++
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04.l | 2 ++
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04a.s | 1 +
>> ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04b.s | 1 +
>> ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp | 4 ++++
>> 18 files changed, 48 insertions(+)
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01.d
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01.l
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01a.s
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01b.s
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02.d
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02.l
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02a.s
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02b.s
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03.d
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03.l
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03a.s
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03b.s
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04.d
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04.l
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04a.s
>> create mode 100644 ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04b.s
>>
>> diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
>> index fa2f1759f31..128c0eda8c4 100644
>> --- a/bfd/elfxx-riscv.c
>> +++ b/bfd/elfxx-riscv.c
>> @@ -3750,6 +3750,14 @@ riscv_merge_arch_attr_info (bfd *ibfd, char
>> *in_arch, char *out_arch,
>> goto cleanup;
>> }
>>
>> + /* Add the implicit subsets implied by the merged subset list, then
>> + check if the result is conflicting. */
>> + riscv_parse_subset_t riscv_rps_ld_merged =
>> + {&merged_subsets, _bfd_error_handler, &xlen_in, NULL, false};
>
> + riscv_parse_add_implicit_subsets (&riscv_rps_ld_merged);
>> + if (!riscv_parse_check_conflicts (&riscv_rps_ld_merged))
>> + goto cleanup;
>> +
>>
>
> Looks reasonable to call riscv_parse_check_conflicts for the merged
> architecture string. But do we need to call
> riscv_parse_add_implicit_subsets? Since I checked all current
> check_implicit_* functions (always/for_i/for_zcf/for_zcd), I think all
> implicit extensions should be added in the each input object already.
>
> Thanks
> Nelson
>
>
>> /* Free the previous merged_arch_str which called xmalloc. */
>> free (merged_arch_str);
>>
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01.d
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01.d
>> new file mode 100644
>> index 00000000000..f99677cb767
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01.d
>> @@ -0,0 +1,5 @@
>> +#source: attr-merge-arch-failed-01a.s
>> +#source: attr-merge-arch-failed-01b.s
>> +#as: -mabi=ilp32
>> +#ld: -r -m[riscv_choose_ilp32_emul]
>> +#error_output: attr-merge-arch-failed-01.l
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01.l
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01.l
>> new file mode 100644
>> index 00000000000..ad6d2630211
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01.l
>> @@ -0,0 +1,2 @@
>> +.*: `zfinx' conflicts with the `f/d/q/zfh/zfhmin' extension
>> +.*: failed to merge target specific data of file .*
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01a.s
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01a.s
>> new file mode 100644
>> index 00000000000..8f2a98f95f3
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01a.s
>> @@ -0,0 +1 @@
>> + .attribute arch, "rv32i_zfinx"
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01b.s
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01b.s
>> new file mode 100644
>> index 00000000000..a44b2a0d346
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-01b.s
>> @@ -0,0 +1 @@
>> + .attribute arch, "rv32if"
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02.d
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02.d
>> new file mode 100644
>> index 00000000000..4fb1980c97d
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02.d
>> @@ -0,0 +1,5 @@
>> +#source: attr-merge-arch-failed-02a.s
>> +#source: attr-merge-arch-failed-02b.s
>> +#as: -mabi=ilp32
>> +#ld: -r -m[riscv_choose_ilp32_emul]
>> +#error_output: attr-merge-arch-failed-02.l
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02.l
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02.l
>> new file mode 100644
>> index 00000000000..930e03123e1
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02.l
>> @@ -0,0 +1,2 @@
>> +.*: zcmp' is incompatible with `d' and `c', or `zcd' extension
>> +.*: failed to merge target specific data of file .*
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02a.s
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02a.s
>> new file mode 100644
>> index 00000000000..3f79059d5d0
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02a.s
>> @@ -0,0 +1 @@
>> + .attribute arch, "rv32i_zcmp"
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02b.s
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02b.s
>> new file mode 100644
>> index 00000000000..95bfe1f6d9f
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-02b.s
>> @@ -0,0 +1 @@
>> + .attribute arch, "rv32i_zcd"
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03.d
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03.d
>> new file mode 100644
>> index 00000000000..def49c3fb3f
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03.d
>> @@ -0,0 +1,5 @@
>> +#source: attr-merge-arch-failed-03a.s
>> +#source: attr-merge-arch-failed-03b.s
>> +#as: -mabi=ilp32
>> +#ld: -r -m[riscv_choose_ilp32_emul]
>> +#error_output: attr-merge-arch-failed-03.l
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03.l
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03.l
>> new file mode 100644
>> index 00000000000..d9075d0c30e
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03.l
>> @@ -0,0 +1,2 @@
>> +.*: `zclsd' conflicts with the `c\+f'/`zcf' extension
>> +.*: failed to merge target specific data of file .*
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03a.s
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03a.s
>> new file mode 100644
>> index 00000000000..f7f9ceb11f6
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03a.s
>> @@ -0,0 +1 @@
>> + .attribute arch, "rv32i_zclsd"
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03b.s
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03b.s
>> new file mode 100644
>> index 00000000000..f18129dc55d
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-03b.s
>> @@ -0,0 +1 @@
>> + .attribute arch, "rv32i_zcf"
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04.d
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04.d
>> new file mode 100644
>> index 00000000000..5445936df44
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04.d
>> @@ -0,0 +1,5 @@
>> +#source: attr-merge-arch-failed-04a.s
>> +#source: attr-merge-arch-failed-04b.s
>> +#as: -mabi=ilp32
>> +#ld: -r -m[riscv_choose_ilp32_emul]
>> +#error_output: attr-merge-arch-failed-04.l
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04.l
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04.l
>> new file mode 100644
>> index 00000000000..930e03123e1
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04.l
>> @@ -0,0 +1,2 @@
>> +.*: zcmp' is incompatible with `d' and `c', or `zcd' extension
>> +.*: failed to merge target specific data of file .*
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04a.s
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04a.s
>> new file mode 100644
>> index 00000000000..e79c25b7828
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04a.s
>> @@ -0,0 +1 @@
>> + .attribute arch, "rv32ic"
>> diff --git a/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04b.s
>> b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04b.s
>> new file mode 100644
>> index 00000000000..c7468e4e072
>> --- /dev/null
>> +++ b/ld/testsuite/ld-riscv-elf/attr-merge-arch-failed-04b.s
>> @@ -0,0 +1 @@
>> + .attribute arch, "rv32id_zcmp"
>> diff --git a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
>> b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
>> index 8e26ccff10a..57f3139c9f6 100644
>> --- a/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
>> +++ b/ld/testsuite/ld-riscv-elf/ld-riscv-elf.exp
>> @@ -157,6 +157,10 @@ if [istarget "riscv*-*-*"] {
>> run_dump_test "attr-merge-arch-01"
>> run_dump_test "attr-merge-arch-02"
>> run_dump_test "attr-merge-arch-03"
>> + run_dump_test "attr-merge-arch-failed-01"
>> + run_dump_test "attr-merge-arch-failed-02"
>> + run_dump_test "attr-merge-arch-failed-03"
>> + run_dump_test "attr-merge-arch-failed-04"
>> run_dump_test "attr-merge-strict-align-01"
>> run_dump_test "attr-merge-strict-align-02"
>> run_dump_test "attr-merge-strict-align-03"
>> --
>> 2.54.0
>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://sourceware.org/pipermail/binutils/attachments/20260707/ea4ab908/attachment-0001.htm>
More information about the Binutils
mailing list