diff options
Diffstat (limited to 'tools/perf/util/dwarf-aux.c')
| -rw-r--r-- | tools/perf/util/dwarf-aux.c | 68 |
1 files changed, 67 insertions, 1 deletions
diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 7aa5fee0da19..3d42a8613869 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -1407,7 +1407,73 @@ Dwarf_Die *die_find_variable_by_addr(Dwarf_Die *sc_die, Dwarf_Addr pc, *offset = data.offset; return result; } -#endif +#endif /* HAVE_DWARF_GETLOCATIONS_SUPPORT */ + +#ifdef HAVE_DWARF_CFI_SUPPORT +static int reg_from_dwarf_op(Dwarf_Op *op) +{ + switch (op->atom) { + case DW_OP_reg0 ... DW_OP_reg31: + return op->atom - DW_OP_reg0; + case DW_OP_breg0 ... DW_OP_breg31: + return op->atom - DW_OP_breg0; + case DW_OP_regx: + case DW_OP_bregx: + return op->number; + default: + break; + } + return -1; +} + +static int offset_from_dwarf_op(Dwarf_Op *op) +{ + switch (op->atom) { + case DW_OP_reg0 ... DW_OP_reg31: + case DW_OP_regx: + return 0; + case DW_OP_breg0 ... DW_OP_breg31: + return op->number; + case DW_OP_bregx: + return op->number2; + default: + break; + } + return -1; +} + +/** + * die_get_cfa - Get frame base information + * @dwarf: a Dwarf info + * @pc: program address + * @preg: pointer for saved register + * @poffset: pointer for saved offset + * + * This function gets register and offset for CFA (Canonical Frame Address) + * by searching the CIE/FDE info. The CFA usually points to the start address + * of the current stack frame and local variables can be located using an offset + * from the CFA. The @preg and @poffset will be updated if it returns 0. + */ +int die_get_cfa(Dwarf *dwarf, u64 pc, int *preg, int *poffset) +{ + Dwarf_CFI *cfi; + Dwarf_Frame *frame = NULL; + Dwarf_Op *ops = NULL; + size_t nops; + + cfi = dwarf_getcfi(dwarf); + if (cfi == NULL) + return -1; + + if (!dwarf_cfi_addrframe(cfi, pc, &frame) && + !dwarf_frame_cfa(frame, &ops, &nops) && nops == 1) { + *preg = reg_from_dwarf_op(ops); + *poffset = offset_from_dwarf_op(ops); + return 0; + } + return -1; +} +#endif /* HAVE_DWARF_CFI_SUPPORT */ /* * die_has_loclist - Check if DW_AT_location of @vr_die is a location list |