diff options
Diffstat (limited to 'gcc/config/mips/linux-unwind.h')
| -rw-r--r-- | gcc/config/mips/linux-unwind.h | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/gcc/config/mips/linux-unwind.h b/gcc/config/mips/linux-unwind.h index 4e71182f5cf..818b436e360 100644 --- a/gcc/config/mips/linux-unwind.h +++ b/gcc/config/mips/linux-unwind.h @@ -106,12 +106,17 @@ mips_fallback_frame_state (struct _Unwind_Context *context, fs->regs.reg[i].loc.offset = (_Unwind_Ptr)&(sc->sc_regs[i]) + reg_offset - new_cfa; } - /* The PC points to the faulting instruction, but the unwind tables - expect it point to the following instruction. We compensate by - reporting a return address at the next instruction. */ + /* "PC & -2" points to the faulting instruction, but the unwind code + searches for "(ADDR & -2) - 1". (See MASK_RETURN_ADDR for the source + of the -2 mask.) Adding 2 here ensures that "(ADDR & -2) - 1" is the + address of the second byte of the faulting instruction. + + Note that setting fs->signal_frame would not work. As the comment + above MASK_RETURN_ADDR explains, MIPS unwinders must earch for an + odd-valued address. */ fs->regs.reg[DWARF_ALT_FRAME_RETURN_COLUMN].how = REG_SAVED_VAL_OFFSET; fs->regs.reg[DWARF_ALT_FRAME_RETURN_COLUMN].loc.offset - = (_Unwind_Ptr)(sc->sc_pc) + 4 - new_cfa; + = (_Unwind_Ptr)(sc->sc_pc) + 2 - new_cfa; fs->retaddr_column = DWARF_ALT_FRAME_RETURN_COLUMN; return _URC_NO_REASON; |