Hi Mathieu, On Tue, Sep 03, 2019 at 04:22:15PM -0600, Mathieu Poirier wrote: > On Fri, Aug 30, 2019 at 02:24:19PM +0800, Leo Yan wrote: > > There has several code pieces need to know the instruction size, but > > now every place calculates the instruction size separately. > > > > This patch refactors to create a new function cs_etm__instr_size() as > > a central place to analyze the instruction length based on ISA type > > and instruction value. > > > > Signed-off-by: Leo Yan <[email protected]> > > --- > > tools/perf/util/cs-etm.c | 44 +++++++++++++++++++++++++++------------- > > 1 file changed, 30 insertions(+), 14 deletions(-) > > > > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c > > index b3a5daaf1a8f..882a0718033d 100644 > > --- a/tools/perf/util/cs-etm.c > > +++ b/tools/perf/util/cs-etm.c > > @@ -914,6 +914,26 @@ static inline int cs_etm__t32_instr_size(struct > > cs_etm_queue *etmq, > > return ((instrBytes[1] & 0xF8) >= 0xE8) ? 4 : 2; > > } > > > > +static inline int cs_etm__instr_size(struct cs_etm_queue *etmq, > > + u8 trace_chan_id, > > + enum cs_etm_isa isa, > > + u64 addr) > > +{ > > + int insn_len; > > + > > + /* > > + * T32 instruction size might be 32-bit or 16-bit, decide by calling > > + * cs_etm__t32_instr_size(). > > + */ > > + if (isa == CS_ETM_ISA_T32) > > + insn_len = cs_etm__t32_instr_size(etmq, trace_chan_id, addr); > > + /* Otherwise, A64 and A32 instruction size are always 32-bit. */ > > + else > > + insn_len = 4; > > + > > + return insn_len; > > +} > > + > > static inline u64 cs_etm__first_executed_instr(struct cs_etm_packet > > *packet) > > { > > /* Returns 0 for the CS_ETM_DISCONTINUITY packet */ > > @@ -938,19 +958,23 @@ static inline u64 cs_etm__instr_addr(struct > > cs_etm_queue *etmq, > > const struct cs_etm_packet *packet, > > u64 offset) > > { > > + int insn_len; > > + > > if (packet->isa == CS_ETM_ISA_T32) { > > u64 addr = packet->start_addr; > > > > while (offset > 0) { > > - addr += cs_etm__t32_instr_size(etmq, > > - trace_chan_id, addr); > > + addr += cs_etm__instr_size(etmq, trace_chan_id, > > + packet->isa, addr); > > offset--; > > } > > return addr; > > } > > > > - /* Assume a 4 byte instruction size (A32/A64) */ > > - return packet->start_addr + offset * 4; > > + /* Return instruction size for A32/A64 */ > > + insn_len = cs_etm__instr_size(etmq, trace_chan_id, > > + packet->isa, packet->start_addr); > > + return packet->start_addr + offset * insn_len; > > This patch will work but from where I stand it makes things difficult to > understand more than anything else. It is also adding coupling between > function > cs_etm__instr_addr() and cs_etm__instr_size(), meaning the code needs to be > carefully inspected in order to make changes to either one.
My purpose is to use a same place to calculate the instruction size, rather than to spread the duplicate codes in several different functions. > Last but not least function cs_etm__instr_size() isn't used in the upcoming > patches. I really don't see what is gained here. Sorry that I forgot to commit my final change into patch 02. I planed to use cs_etm__instr_size() in patch 02; patch 02 has function cs_etm__add_stack_event(), which also needs to get the instruction size when it sends stack event. After apply patch 02, tools/perf/util/cs-etm.c will have below three functions to caculate instruction size; this is the main reason I want to refactor the code for instruction size. cs_etm__instr_addr() cs_etm__copy_insn() cs_etm__add_stack_event() If this lets code more difficult to understand, will drop it. Thanks, Leo Yan > > } > > > > static void cs_etm__update_last_branch_rb(struct cs_etm_queue *etmq, > > @@ -1090,16 +1114,8 @@ static void cs_etm__copy_insn(struct cs_etm_queue > > *etmq, > > return; > > } > > > > - /* > > - * T32 instruction size might be 32-bit or 16-bit, decide by calling > > - * cs_etm__t32_instr_size(). > > - */ > > - if (packet->isa == CS_ETM_ISA_T32) > > - sample->insn_len = cs_etm__t32_instr_size(etmq, trace_chan_id, > > - sample->ip); > > - /* Otherwise, A64 and A32 instruction size are always 32-bit. */ > > - else > > - sample->insn_len = 4; > > + sample->insn_len = cs_etm__instr_size(etmq, trace_chan_id, > > + packet->isa, sample->ip); > > > > cs_etm__mem_access(etmq, trace_chan_id, sample->ip, > > sample->insn_len, (void *)sample->insn); > > -- > > 2.17.1 > >
