[binutils-gdb] Re: RISC-V: riscv_parse_subset_t's isa_spec is only parser input

[Alan Modra]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=618fc86830cb51295ff9e177c0c55ebc93e5efc5

commit 618fc86830cb51295ff9e177c0c55ebc93e5efc5
Author: Alan Modra <amodra@gmail.com>
Date:   Mon Jun 8 09:13:51 2026 +0930

    Re: RISC-V: riscv_parse_subset_t's isa_spec is only parser input
    
    check_compiler_available fails with a ld segfault linking
    int main (void) { return 0; }
    
    Program received signal SIGSEGV, Segmentation fault.
    0x0000000000466a64 in riscv_parse_add_subset (rps=rps@entry=0x7fffffffd450, subset=subset@entry=0x962ca0 "zaamo", major=-1, minor=-1, implicit=implicit@entry=true) at /home/alan/src/binutils-gdb/bfd/elfxx-riscv.c:1947
    1947        riscv_get_default_ext_version (*rps->isa_spec, subset,
    (gdb) p rps->isa_spec
    $1 = (const enum riscv_spec_class *) 0x0
    
    This was triggered when calling riscv_merge_attributes for crti.o
    which had
    (gdb) p ibfd->tdata.elf_obj_data->known_obj_attributes[OBJ_ATTR_PROC][Tag_RISCV_arch]
    $5 = {type = 2, i = 0, s = 0x97e4c0 "rv64i2p1_m2p0_a2p1_f2p2_d2p2_c2p0_zicsr2p0_zifencei2p0_zmmul1p0"}
    
    Fix the segfault by reinstating a NULL check removed with commit
    413cf36d8e81

Diff:
---
 bfd/elfxx-riscv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
index df6ff6448c1..67fbf0f72ca 100644
--- a/bfd/elfxx-riscv.c
+++ b/bfd/elfxx-riscv.c
@@ -1942,8 +1942,9 @@ riscv_parse_add_subset (riscv_parse_subset_t *rps,
   int major_version = major;
   int minor_version = minor;
 
-  if (major_version == RISCV_UNKNOWN_VERSION
+  if ((major_version == RISCV_UNKNOWN_VERSION
        || minor_version == RISCV_UNKNOWN_VERSION)
+      && rps->isa_spec != NULL)
     riscv_get_default_ext_version (*rps->isa_spec, subset,
 				   &major_version, &minor_version);