DR_EXPORT
bool
drmgr_insert_read_tls_field(void *drcontext, int idx,
instrlist_t *ilist, instr_t *where, reg_id_t reg)
{
tls_array_t *tls = (tls_array_t *) dr_get_tls_field(drcontext);
if (idx < 0 || idx > MAX_NUM_TLS || !tls_taken[idx] || tls == NULL)
return false;
if (!reg_is_gpr(reg) || !reg_is_pointer_sized(reg))
return false;
dr_insert_read_tls_field(drcontext, ilist, where, reg);
instrlist_meta_preinsert(ilist, where, INSTR_CREATE_mov_ld
(drcontext, opnd_create_reg(reg),
OPND_CREATE_MEMPTR(reg, offsetof(tls_array_t, tls) +
idx*sizeof(void*))));
return true;
}
static void
insert_counter_update(void *drcontext, instrlist_t *bb, instr_t *where, int offset)
{
/* Since the inc instruction clobbers 5 of the arithmetic eflags,
* we have to save them around the inc. We could be more efficient
* by not bothering to save the overflow flag and constructing our
* own sequence of instructions to save the other 5 flags (using
* lahf) or by doing a liveness analysis on the flags and saving
* only if live.
*/
dr_save_reg(drcontext, bb, where, DR_REG_XAX, SPILL_SLOT_1);
dr_save_arith_flags_to_xax(drcontext, bb, where);
/* Increment the global counter using the lock prefix to make it atomic
* across threads. It would be cheaper to aggregate the thread counters
* in the exit events, but this sample is intended to illustrate inserted
* instrumentation.
*/
instrlist_meta_preinsert(bb, where, LOCK(INSTR_CREATE_inc
(drcontext, OPND_CREATE_ABSMEM(((byte *)&global_count) + offset, OPSZ_4))));
/* Increment the thread private counter. */
if (dr_using_all_private_caches()) {
per_thread_t *data = (per_thread_t *) dr_get_tls_field(drcontext);
/* private caches - we can use an absolute address */
instrlist_meta_preinsert(bb, where, INSTR_CREATE_inc(drcontext,
OPND_CREATE_ABSMEM(((byte *)&data) + offset, OPSZ_4)));
} else {
/* shared caches - we must indirect via thread local storage */
/* We spill xbx to use a scratch register (we could do a liveness
* analysis to try and find a dead register to use). Note that xax
* is currently holding the saved eflags. */
dr_save_reg(drcontext, bb, where, DR_REG_XBX, SPILL_SLOT_2);
dr_insert_read_tls_field(drcontext, bb, where, DR_REG_XBX);
instrlist_meta_preinsert(bb, where,
INSTR_CREATE_inc(drcontext, OPND_CREATE_MEM32(DR_REG_XBX, offset)));
dr_restore_reg(drcontext, bb, where, DR_REG_XBX, SPILL_SLOT_2);
}
/* Restore flags and xax. */
dr_restore_arith_flags_from_xax(drcontext, bb, where);
dr_restore_reg(drcontext, bb, where, DR_REG_XAX, SPILL_SLOT_1);
}
/** Adds instrumentation that records fragment execution. */
struct instr_info_t instrument_frag(void* ctx,
instrlist_t* frag,
frag_id_t id) {
const size_t offsetof_current = offsetof(struct trace_buffer_t, current);
ptr_int_t frag_id = id; // sign-extended for OPND_CREATE_INT32
#ifdef TRACE_DEBUG
app_pc frag_pc;
#endif
app_pc xl8_pc;
instr_t* where;
instr_t* before;
struct instr_info_t instr_info;
instr_t* store;
instr_t* first;
#ifdef TRACE_DEBUG
dr_fprintf(STDERR, "debug: instrument_frag(0x%" PRIxPTR ")\n", frag_id);
frag_pc = instr_get_app_pc(instrlist_first(frag));
instrlist_disassemble(ctx, frag_pc, frag, STDERR);
#endif
where = configure_instr(&instr_info, frag);
xl8_pc = instr_get_app_pc(where);
before = instr_get_prev(where);
#define INSERT(instr) prexl8(frag, where, (instr), xl8_pc)
// Add instrumentation.
// save tls_reg
if(instr_info.restore_tls_reg) {
dr_save_reg(ctx, frag, where, instr_info.tls_reg, SPILL_SLOT_2);
}
// save current_reg
if(instr_info.restore_current_reg) {
dr_save_reg(ctx, frag, where, instr_info.current_reg, SPILL_SLOT_3);
}
// tls_reg = tb
dr_insert_read_tls_field(ctx, frag, where, instr_info.tls_reg);
// current_reg = tb->current
INSERT(
INSTR_CREATE_mov_ld(
ctx,
opnd_create_reg(instr_info.current_reg),
OPND_CREATE_MEMPTR(instr_info.tls_reg, offsetof_current)));
// *current_reg = bb_id
store = INSERT(
INSTR_CREATE_mov_st(
ctx,
OPND_CREATE_MEMPTR(instr_info.current_reg, 0),
OPND_CREATE_INT32(frag_id)));
// current_reg += sizeof(bb_id)
INSERT(
INSTR_CREATE_lea(
ctx,
opnd_create_reg(instr_info.current_reg),
OPND_CREATE_MEM_lea(instr_info.current_reg,
DR_REG_NULL,
0,
sizeof(frag_id_t))));
// tb->current = current_reg
INSERT(
INSTR_CREATE_mov_st(
ctx,
OPND_CREATE_MEMPTR(instr_info.tls_reg, offsetof_current),
opnd_create_reg(instr_info.current_reg)));
// restore current_reg
if(instr_info.restore_current_reg) {
dr_restore_reg(ctx, frag, where, instr_info.current_reg, SPILL_SLOT_3);
}
// restore tls_reg
if(instr_info.restore_tls_reg) {
dr_restore_reg(ctx, frag, where, instr_info.tls_reg, SPILL_SLOT_2);
}
#undef INSERT
// Compute instrumentation instructions offsets.
if(before) {
first = instr_get_next(before);
} else {
first = instrlist_first(frag);
}
instr_info.first_offset = get_offset(ctx,
instrlist_first(frag),
first);
instr_info.store_offset = get_offset(ctx,
instrlist_first(frag),
store);
#ifdef TRACE_DUMP_BB
instrlist_disassemble(ctx, frag_pc, frag, STDERR);
#endif
#ifdef TRACE_DEBUG
dr_fprintf(STDERR,
"debug: instrument_frag() done,"
" first_offset=0x%" PRIx32
" store_offset=0x%" PRIx32
"\n",
instr_info.first_offset,
instr_info.store_offset);
#endif
return instr_info;
}
