I built GDB with --enable-targets=all, and am running on an x86-64 GNU/Linux host. If I start GDB and load an executable (for example GDB itself), and then run 'maint selftest', I see 1 failure. In contrast, if I start GDB and don't load an executable, I see 0 failures. Here's the error(s) that I see: Running selftest print_one_insn. Self test failed: arch arm: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv2: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv2a: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv3: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv3m: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv4: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv4t: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv5: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv5t: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv5te: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch xscale: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch ep9312: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch iwmmxt: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch iwmmxt2: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv5tej: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv6: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv6kz: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv6t2: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv6k: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv7: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv6-m: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv6s-m: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv7e-m: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv8-a: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv8-r: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv8-m.base: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv8-m.main: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch armv8.1-m.main: self-test failed at ../../src/gdb/disasm-selftests.c:165 Self test failed: arch arm_any: self-test failed at ../../src/gdb/disasm-selftests.c:165 warning: A handler for the OS ABI "GNU/Linux" is not built into this configuration of GDB. Attempting to continue with the default cris:common_v10_v32 settings. Self test failed: self-test failed at ../../src/gdb/selftest-arch.c:85 I had a quick look and it appears that the ARM disassembler gets into a state where it thinks it is disassembling in thumb mode. When there is no executable loaded this is not the case.
(In reply to Andrew Burgess from comment #0) > Self test failed: arch armv8.1-m.main: self-test failed at > ../../src/gdb/disasm-selftests.c:165 The first error I run into is this one, and I've debugged it. 1. With exec. In gdb_print_insn_arm, we run into this and set info->flags |= USER_SPECIFIED_MACHINE_TYPE: ... /* GDB is able to get bfd_mach from the exe_bfd, info->mach is accurate, so mark USER_SPECIFIED_MACHINE_TYPE bit. Otherwise, opcodes/arm-dis.c:print_insn reset info->mach, and it will trigger the assert on the mismatch of info->mach and bfd_get_mach (current_program_space->exec_bfd ()) in default_print_insn. */ if (current_program_space->exec_bfd () != NULL) info->flags |= USER_SPECIFIED_MACHINE_TYPE; ... and consequently we don't do this in print_insn: ... if ((info->flags & USER_SPECIFIED_MACHINE_TYPE) == 0) info->mach = bfd_mach_arm_unknown; ... so we end up doing this in select_arm_features: ... case bfd_mach_arm_8_1M_MAIN: ARM_SET_FEATURES (ARM_ARCH_V8_1M_MAIN); arm_feature_set mve_all = ARM_FEATURE_CORE_HIGH (ARM_EXT2_MVE | ARM_EXT2_MVE_FP); ARM_MERGE_FEATURE_SETS (arch_fset, arch_fset, mve_all); force_thumb = 1; break; ... With force_thumb set, we disassemble only two bytes, and the selftest fails. 2. Without exec. - in gdb_print_insn_arm, we don't set info->flags |= USER_SPECIFIED_MACHINE_TYPE. - in print_insn, we do bfd_mach_arm_unknown - in select_arm_features, we don't set force_thumb Without force_thumb set, we disassemble four bytes, and the selftest passes.
(In reply to Tom de Vries from comment #1) > if (current_program_space->exec_bfd () != NULL) > info->flags |= USER_SPECIFIED_MACHINE_TYPE; > ... This seems incorrect, given that exec arch can be different from the disassembly arch. This fixes that: ... diff --git a/gdb/arm-tdep.c b/gdb/arm-tdep.c index e4e7aec4e1c..ab6999ae209 100644 --- a/gdb/arm-tdep.c +++ b/gdb/arm-tdep.c @@ -7727,7 +7727,9 @@ gdb_print_insn_arm (bfd_vma memaddr, disassemble_info *info) the assert on the mismatch of info->mach and bfd_get_mach (current_program_space->exec_bfd ()) in default_print_insn. */ - if (current_program_space->exec_bfd () != NULL) + if (current_program_space->exec_bfd () != NULL + && (current_program_space->exec_bfd ()->arch_info + == gdbarch_bfd_arch_info (gdbarch))) info->flags |= USER_SPECIFIED_MACHINE_TYPE; return default_print_insn (memaddr, info); ... and consequently the unit test passes for me (not building with --all-targets though) with and without exec.
Looks OK with the usual NULL -> nullptr fixed. Thanks for the patch.
(In reply to Luis Machado from comment #3) > Looks OK with the usual NULL -> nullptr fixed. > > Thanks for the patch. Oops, I forgot to update that before committing. Oh well...
Not a big deal. I'm sure we'll revisit these constants again in the future.