/* save aflags from eax */
void
umbra_save_eax_aflags(void *drcontext,
umbra_info_t *info,
instrlist_t *ilist,
instr_t *where)
{
instr_t *instr;
instr = INSTR_CREATE_mov_st(drcontext,
OPND_CREATE_ABSMEM(&info->aflags,
OPSZ_4),
opnd_create_reg(DR_REG_EAX));
instrlist_meta_preinsert(ilist, where, instr);
}
/* Insert arithmetic flags restore code with more control.
* For x86:
* - skip %eax restore if !restore_reg
* - restore %eax from reg if reg is not DR_REG_NULL
* - restore %eax from slot otherwise
* For ARM:
* - restores flags from reg
* - restores reg to slot, unless !restore_reg.
* Routine merge_prev_drx_aflags_switch looks for labels inserted by
* drx_restore_arith_flags, so changes to this routine may affect
* merge_prev_drx_aflags_switch.
*/
static void
drx_restore_arith_flags(void *drcontext, instrlist_t *ilist, instr_t *where,
bool restore_reg, bool restore_oflag,
dr_spill_slot_t slot, reg_id_t reg)
{
instr_t *instr;
ilist_insert_note_label(drcontext, ilist, where,
NOTE_VAL(DRX_NOTE_AFLAGS_RESTORE_BEGIN));
#ifdef X86
if (restore_oflag) {
/* add 0x7f, %al */
instr = INSTR_CREATE_add(drcontext, opnd_create_reg(DR_REG_AL),
OPND_CREATE_INT8(0x7f));
MINSERT(ilist, where, instr);
}
/* sahf */
instr = INSTR_CREATE_sahf(drcontext);
instr_set_note(instr, NOTE_VAL(DRX_NOTE_AFLAGS_RESTORE_SAHF));
MINSERT(ilist, where, instr);
/* restore eax if necessary */
if (restore_reg) {
if (reg != DR_REG_NULL) {
ASSERT(reg >= DR_REG_START_GPR && reg <= DR_REG_STOP_GPR &&
reg != DR_REG_XAX, "wrong dead reg");
MINSERT(ilist, where,
INSTR_CREATE_mov_st(drcontext,
opnd_create_reg(DR_REG_XAX),
opnd_create_reg(reg)));
} else {
ASSERT(slot >= SPILL_SLOT_1 && slot <= SPILL_SLOT_MAX,
"wrong spill slot");
dr_restore_reg(drcontext, ilist, where, DR_REG_XAX, slot);
}
}
#elif defined(ARM)
ASSERT(reg >= DR_REG_START_GPR && reg <= DR_REG_STOP_GPR, "reg must be a GPR");
instr = INSTR_CREATE_mrs(drcontext, opnd_create_reg(reg),
opnd_create_reg(DR_REG_CPSR));
instr_set_note(instr, NOTE_VAL(DRX_NOTE_AFLAGS_RESTORE_SAHF));
MINSERT(ilist, where, instr);
if (restore_reg) {
ASSERT(slot >= SPILL_SLOT_1 && slot <= SPILL_SLOT_MAX,
"wrong spill slot");
dr_restore_reg(drcontext, ilist, where, reg, slot);
}
#endif
ilist_insert_note_label(drcontext, ilist, where,
NOTE_VAL(DRX_NOTE_AFLAGS_RESTORE_END));
}
static void
test_x64_abs_addr(void *dc)
{
/* 48 a1 ef be ad de ef be ad de mov 0xdeadbeefdeadbeef -> %rax
* 48 a3 ef be ad de ef be ad de mov %rax -> 0xdeadbeefdeadbeef
*/
instr_t *instr;
opnd_t abs_addr = opnd_create_abs_addr((void*)0xdeadbeefdeadbeef, OPSZ_8);
/* movabs load */
instr = INSTR_CREATE_mov_ld(dc, opnd_create_reg(DR_REG_RAX), abs_addr);
test_instr_encode(dc, instr, 10); /* REX + op + 8 */
/* movabs store */
instr = INSTR_CREATE_mov_st(dc, abs_addr, opnd_create_reg(DR_REG_RAX));
test_instr_encode(dc, instr, 10); /* REX + op + 8 */
}
/* save reg before where in ilist */
void
umbra_save_reg(void *drcontext,
umbra_info_t *info,
instrlist_t *ilist,
instr_t *where,
reg_id_t reg)
{
int slot;
instr_t *instr;
DR_ASSERT(reg >= REG_SPILL_START && reg <= REG_SPILL_STOP);
slot = reg - REG_SPILL_START;
instr = INSTR_CREATE_mov_st(drcontext,
OPND_CREATE_ABSMEM(&info->spill_regs[slot],
OPSZ_PTR),
opnd_create_reg(reg));
instrlist_meta_preinsert(ilist, where, instr);
}
/* Insert arithmetic flags saving code with more control.
* For x86:
* - skip %eax save if !save_reg
* - save %eax to reg if reg is not DR_REG_NULL,
* - save %eax to slot otherwise
* For ARM:
* - saves flags to reg
* - saves reg first to slot, unless !save_reg.
*/
static void
drx_save_arith_flags(void *drcontext, instrlist_t *ilist, instr_t *where,
bool save_reg, bool save_oflag,
dr_spill_slot_t slot, reg_id_t reg)
{
#ifdef X86
instr_t *instr;
/* save %eax if necessary */
if (save_reg) {
if (reg != DR_REG_NULL) {
ASSERT(reg >= DR_REG_START_GPR && reg <= DR_REG_STOP_GPR &&
reg != DR_REG_XAX, "wrong dead reg");
MINSERT(ilist, where,
INSTR_CREATE_mov_st(drcontext,
opnd_create_reg(reg),
opnd_create_reg(DR_REG_XAX)));
} else {
ASSERT(slot >= SPILL_SLOT_1 && slot <= SPILL_SLOT_MAX,
"wrong spill slot");
dr_save_reg(drcontext, ilist, where, DR_REG_XAX, slot);
}
}
/* lahf */
instr = INSTR_CREATE_lahf(drcontext);
MINSERT(ilist, where, instr);
if (save_oflag) {
/* seto %al */
instr = INSTR_CREATE_setcc(drcontext, OP_seto, opnd_create_reg(DR_REG_AL));
MINSERT(ilist, where, instr);
}
#elif defined(ARM)
ASSERT(reg >= DR_REG_START_GPR && reg <= DR_REG_STOP_GPR, "reg must be a GPR");
if (save_reg) {
ASSERT(slot >= SPILL_SLOT_1 && slot <= SPILL_SLOT_MAX,
"wrong spill slot");
dr_save_reg(drcontext, ilist, where, reg, slot);
}
MINSERT(ilist, where, INSTR_CREATE_msr
(drcontext, opnd_create_reg(DR_REG_CPSR), OPND_CREATE_INT_MSR_NZCVQG(),
opnd_create_reg(reg)));
#endif
}
DR_EXPORT
bool
drmgr_insert_write_tls_field(void *drcontext, int idx,
instrlist_t *ilist, instr_t *where, reg_id_t reg,
reg_id_t scratch)
{
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) ||
!reg_is_gpr(scratch) || !reg_is_pointer_sized(scratch))
return false;
dr_insert_read_tls_field(drcontext, ilist, where, scratch);
instrlist_meta_preinsert(ilist, where, INSTR_CREATE_mov_st
(drcontext,
OPND_CREATE_MEMPTR(scratch, offsetof(tls_array_t, tls) +
idx*sizeof(void*)),
opnd_create_reg(reg)));
return true;
}
static void dynamic_info_instrumentation(void *drcontext, instrlist_t *ilist, instr_t *where,
instr_t * static_info)
{
/*
issues that may arise
1. pc and eflags is uint but in 64 bit mode 8 byte transfers are done -> so far no problem (need to see this)
need to see whether there is a better way
2. double check all the printing
*/
/*
this function does the acutal instrumentation
arguments -
we get a filled pointer here about the operand types for a given instruction (srcs and dests)
1) increment the pointer to the instr_trace buffers
2) add this pointer to instr_trace_t wrapper
3) check whether any of the srcs and dests have memory operations; if so add a lea instruction and get the dynamic address
Add this address to instr_trace_t structure
4) if the buffer is full call a function to dump it to the file and restore the head ptr of the buffer
(lean function is used utilizing a code cache to limit code bloat needed for a clean call before every instruction.)
*/
instr_t *instr, *call, *restore, *first, *second;
opnd_t ref, opnd1, opnd2;
reg_id_t reg1 = DR_REG_XBX; /* We can optimize it by picking dead reg */
reg_id_t reg2 = DR_REG_XCX; /* reg2 must be ECX or RCX for jecxz */
reg_id_t reg3 = DR_REG_XAX;
per_thread_t *data;
uint pc;
uint i;
module_data_t * module_data;
if (client_arg->instrace_mode == DISASSEMBLY_TRACE){
dr_insert_clean_call(drcontext, ilist, where, clean_call_disassembly_trace, false, 0);
return;
}
data = drmgr_get_tls_field(drcontext, tls_index);
/* Steal the register for memory reference address *
* We can optimize away the unnecessary register save and restore
* by analyzing the code and finding the register is dead.
*/
dr_save_reg(drcontext, ilist, where, reg1, SPILL_SLOT_2);
dr_save_reg(drcontext, ilist, where, reg2, SPILL_SLOT_3);
dr_save_reg(drcontext, ilist, where, reg3, SPILL_SLOT_4);
drmgr_insert_read_tls_field(drcontext, tls_index, ilist, where, reg2);
/* Load data->buf_ptr into reg2 */
opnd1 = opnd_create_reg(reg2);
opnd2 = OPND_CREATE_MEMPTR(reg2, offsetof(per_thread_t, buf_ptr));
instr = INSTR_CREATE_mov_ld(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* buf_ptr->static_info_instr = static_info; */
/* Move static_info to static_info_instr field of buf (which is a instr_trace_t *) */
opnd1 = OPND_CREATE_MEMPTR(reg2, offsetof(instr_trace_t, static_info_instr));
instrlist_insert_mov_immed_ptrsz(drcontext, (ptr_int_t)static_info, opnd1, ilist, where, &first, &second);
/* buf_ptr->num_mem = 0; */
opnd1 = OPND_CREATE_MEMPTR(reg2, offsetof(instr_trace_t, num_mem));
instrlist_insert_mov_immed_ptrsz(drcontext, (ptr_int_t)0, opnd1, ilist, where, &first, &second);
for (i = 0; i<instr_num_dsts(where); i++){
if (opnd_is_memory_reference(instr_get_dst(where, i))){
ref = instr_get_dst(where, i);
DR_ASSERT(opnd_is_null(ref) == false);
dr_restore_reg(drcontext, ilist, where, reg1, SPILL_SLOT_2);
dr_restore_reg(drcontext, ilist, where, reg2, SPILL_SLOT_3);
#ifdef DEBUG_MEM_REGS
dr_insert_clean_call(drcontext, ilist, where, clean_call_disassembly_trace, false, 0);
dr_insert_clean_call(drcontext, ilist, where, clean_call_print_regvalues, false, 0);
#endif
drutil_insert_get_mem_addr(drcontext, ilist, where, ref, reg1, reg2);
#ifdef DEBUG_MEM_REGS
dr_insert_clean_call(drcontext, ilist, where, clean_call_print_regvalues, false, 0);
#endif
#ifdef DEBUG_MEM_STATS
dr_insert_clean_call(drcontext, ilist, where, clean_call_disassembly_trace, false, 0);
dr_insert_clean_call(drcontext, ilist, where, clean_call_mem_stats, false, 1, opnd_create_reg(reg1));
#endif
dr_insert_clean_call(drcontext, ilist, where, clean_call_populate_mem, false, 3, opnd_create_reg(reg1), OPND_CREATE_INT32(i), OPND_CREATE_INT32(DST_TYPE));
}
}
for (i = 0; i<instr_num_srcs(where); i++){
if (opnd_is_memory_reference(instr_get_src(where, i))){
ref = instr_get_src(where, i);
DR_ASSERT(opnd_is_null(ref) == false);
dr_restore_reg(drcontext, ilist, where, reg1, SPILL_SLOT_2);
dr_restore_reg(drcontext, ilist, where, reg2, SPILL_SLOT_3);
#ifdef DEBUG_MEM_REGS
dr_insert_clean_call(drcontext, ilist, where, clean_call_disassembly_trace, false, 0);
dr_insert_clean_call(drcontext, ilist, where, clean_call_print_regvalues, false, 0);
#endif
drutil_insert_get_mem_addr(drcontext, ilist, where, ref, reg1, reg2);
#ifdef DEBUG_MEM_REGS
dr_insert_clean_call(drcontext, ilist, where, clean_call_print_regvalues, false, 0);
#endif
#ifdef DEBUG_MEM_STATS
dr_insert_clean_call(drcontext, ilist, where, clean_call_disassembly_trace, false, 0);
dr_insert_clean_call(drcontext, ilist, where, clean_call_mem_stats, false, 1, opnd_create_reg(reg1));
#endif
dr_insert_clean_call(drcontext, ilist, where, clean_call_populate_mem, false, 3, opnd_create_reg(reg1), OPND_CREATE_INT32(i), OPND_CREATE_INT32(SRC_TYPE));
}
}
drmgr_insert_read_tls_field(drcontext, tls_index, ilist, where, reg2);
/* Load data->buf_ptr into reg2 */
opnd1 = opnd_create_reg(reg2);
opnd2 = OPND_CREATE_MEMPTR(reg2, offsetof(per_thread_t, buf_ptr));
instr = INSTR_CREATE_mov_ld(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* arithmetic flags are saved here for buf_ptr->eflags filling */
dr_save_arith_flags_to_xax(drcontext, ilist, where);
/* load the eflags */
opnd1 = OPND_CREATE_MEMPTR(reg2, offsetof(instr_trace_t, eflags));
opnd2 = opnd_create_reg(reg3);
instr = INSTR_CREATE_mov_st(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* load the app_pc */
opnd1 = OPND_CREATE_MEMPTR(reg2, offsetof(instr_trace_t, pc));
module_data = dr_lookup_module(instr_get_app_pc(where));
//dynamically generated code - module information not available - then just store 0 at the pc slot of the instr_trace data
if (module_data != NULL){
pc = instr_get_app_pc(where) - module_data->start;
dr_free_module_data(module_data);
}
else{
pc = 0;
}
instrlist_insert_mov_immed_ptrsz(drcontext, (ptr_int_t)pc, opnd1, ilist, where, &first, &second);
/* buf_ptr++; */
/* Increment reg value by pointer size using lea instr */
opnd1 = opnd_create_reg(reg2);
opnd2 = opnd_create_base_disp(reg2, DR_REG_NULL, 0,
sizeof(instr_trace_t),
OPSZ_lea);
instr = INSTR_CREATE_lea(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* Update the data->buf_ptr */
drmgr_insert_read_tls_field(drcontext, tls_index, ilist, where, reg1);
opnd1 = OPND_CREATE_MEMPTR(reg1, offsetof(per_thread_t, buf_ptr));
opnd2 = opnd_create_reg(reg2);
instr = INSTR_CREATE_mov_st(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* we use lea + jecxz trick for better performance
* lea and jecxz won't disturb the eflags, so we won't insert
* code to save and restore application's eflags.
*/
/* lea [reg2 - buf_end] => reg2 */
opnd1 = opnd_create_reg(reg1);
opnd2 = OPND_CREATE_MEMPTR(reg1, offsetof(per_thread_t, buf_end));
instr = INSTR_CREATE_mov_ld(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
opnd1 = opnd_create_reg(reg2);
opnd2 = opnd_create_base_disp(reg1, reg2, 1, 0, OPSZ_lea);
instr = INSTR_CREATE_lea(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* jecxz call */
call = INSTR_CREATE_label(drcontext);
opnd1 = opnd_create_instr(call);
instr = INSTR_CREATE_jecxz(drcontext, opnd1);
instrlist_meta_preinsert(ilist, where, instr);
/* jump restore to skip clean call */
restore = INSTR_CREATE_label(drcontext);
opnd1 = opnd_create_instr(restore);
instr = INSTR_CREATE_jmp(drcontext, opnd1);
instrlist_meta_preinsert(ilist, where, instr);
/* clean call */
/* We jump to lean procedure which performs full context switch and
* clean call invocation. This is to reduce the code cache size.
*/
instrlist_meta_preinsert(ilist, where, call);
/* mov restore DR_REG_XCX */
opnd1 = opnd_create_reg(reg2);
/* this is the return address for jumping back from lean procedure */
opnd2 = opnd_create_instr(restore);
/* We could use instrlist_insert_mov_instr_addr(), but with a register
* destination we know we can use a 64-bit immediate.
*/
instr = INSTR_CREATE_mov_imm(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* jmp code_cache */
opnd1 = opnd_create_pc(code_cache);
instr = INSTR_CREATE_jmp(drcontext, opnd1);
instrlist_meta_preinsert(ilist, where, instr);
/* restore %reg */
instrlist_meta_preinsert(ilist, where, restore);
//dr_restore_arith_flags_from_xax(drcontext, ilist, where);
dr_restore_reg(drcontext, ilist, where, reg1, SPILL_SLOT_2);
dr_restore_reg(drcontext, ilist, where, reg2, SPILL_SLOT_3);
dr_restore_reg(drcontext, ilist, where, reg3, SPILL_SLOT_4);
//instrlist_disassemble(drcontext, instr_get_app_pc(instrlist_first(ilist)), ilist, logfile);
}
static void
instrument_mem(void *drcontext, instrlist_t *ilist, instr_t *where,
int pos, bool write)
{
instr_t *instr;
opnd_t ref, opnd1, opnd2;
reg_id_t reg1 = DR_REG_XAX; /* We can optimize it by picking dead reg */
reg_id_t reg2 = DR_REG_XCX; /* reg2 must be ECX or RCX for jecxz */
if (write)
ref = instr_get_dst(where, pos);
else
ref = instr_get_src(where, pos);
dr_save_reg(drcontext, ilist, where, reg1, SPILL_SLOT_2);
dr_save_reg(drcontext, ilist, where, reg2, SPILL_SLOT_3);
// reg2 = RBufIdx
opnd1 = opnd_create_reg(reg2);
opnd2 = OPND_CREATE_ABSMEM((byte *)&RBufIdx, OPSZ_4);
instr = INSTR_CREATE_mov_ld(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
// save flags since we are using inc, and
dr_save_arith_flags_to_xax(drcontext, ilist, where);
// reg2 = reg2 & RBUF_SIZE
opnd1 = opnd_create_reg(reg2);
opnd2 = OPND_CREATE_INT32(RBUF_SIZE);
instr = INSTR_CREATE_and(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
dr_restore_arith_flags_from_xax(drcontext, ilist, where);
// reg1 = &RBuf
opnd1 = opnd_create_reg(reg1);
opnd2 = OPND_CREATE_INTPTR(RBuf);
instr = INSTR_CREATE_mov_imm(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
// reg1 = reg1 + reg2 * sizeof(uint)
// = RBuf + RBufIdx * sizeof(uint)
// = RBuf[RBufIdx]
opnd1 = opnd_create_reg(reg1);
opnd2 = opnd_create_base_disp(reg1, reg2, sizeof(uint), 0, OPSZ_lea);
instr = INSTR_CREATE_lea(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
// RBuf[RBufIdx].addr = addr;
opnd1 = OPND_CREATE_MEMPTR(reg1, 0);
drutil_insert_get_mem_addr(drcontext, ilist, where, ref, reg2, reg1);
opnd2 = opnd_create_reg(reg2);
instr = INSTR_CREATE_mov_st(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
dr_save_arith_flags_to_xax(drcontext, ilist, where);
// reg2 = RBufIdx
opnd1 = opnd_create_reg(reg2);
opnd2 = OPND_CREATE_ABSMEM((byte *)&RBufIdx, OPSZ_4);
instr = INSTR_CREATE_mov_ld(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
// reg2 = reg2 + 1
opnd1 = opnd_create_reg(reg2);
instr = INSTR_CREATE_inc(drcontext, opnd1);
instrlist_meta_preinsert(ilist, where, instr);
// RBufIdx = reg2
opnd1 = OPND_CREATE_ABSMEM((byte *)&RBufIdx, OPSZ_4);
opnd2 = opnd_create_reg(reg2);
instr = INSTR_CREATE_mov_st(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
dr_restore_arith_flags_from_xax(drcontext, ilist, where);
dr_restore_reg(drcontext, ilist, where, reg1, SPILL_SLOT_2);
dr_restore_reg(drcontext, ilist, where, reg2, SPILL_SLOT_3);
}
static dr_emit_flags_t
event_basic_block(void *drcontext, void *tag, instrlist_t *bb,
bool for_trace, bool translating)
{
instr_t *first = instrlist_first(bb);
app_pc pc = dr_fragment_app_pc(tag);
instr_t *mov1, *mov2;
/* We try to avoid register stealing by using "dead" register if possible.
* However, technically, a fault could come in and want the original value
* of the "dead" register, but that's too corner-case for us.
*/
reg_id_t reg = bb_find_dead_reg(bb);
bool steal = (reg == DR_REG_NULL);
if (reg == DR_REG_NULL)
reg = DR_REG_XCX; /* randomly use one if no dead reg found */
/* save register if necessary */
if (steal)
dr_save_reg(drcontext, bb, first, reg, SPILL_SLOT_1);
/* load buffer pointer from TLS field */
MINSERT(bb, first, INSTR_CREATE_mov_ld
(drcontext,
opnd_create_reg(reg),
opnd_create_far_base_disp(tls_seg, DR_REG_NULL, DR_REG_NULL,
0, tls_offs, OPSZ_PTR)));
/* store bb's start pc into the buffer */
instrlist_insert_mov_immed_ptrsz(drcontext, (ptr_int_t)pc,
OPND_CREATE_MEMPTR(reg, 0),
bb, first, &mov1, &mov2);
DR_ASSERT(mov1 != NULL);
instr_set_ok_to_mangle(mov1, false);
if (mov2 != NULL)
instr_set_ok_to_mangle(mov2, false);
/* update the TLS buffer pointer by incrementing just the bottom 16 bits of
* the pointer
*/
if (bb_aflags_are_dead(bb, first)) {
/* if aflags are dead, we use add directly */
MINSERT(bb, first, INSTR_CREATE_add
(drcontext,
opnd_create_far_base_disp(tls_seg, DR_REG_NULL, DR_REG_NULL,
0, tls_offs, OPSZ_2),
OPND_CREATE_INT8(sizeof(app_pc))));
} else {
reg_id_t reg_16;
#ifdef X64
reg_16 = reg_32_to_16(reg_64_to_32(reg));
#else
reg_16 = reg_32_to_16(reg);
#endif
/* we use lea to avoid aflags save/restore */
MINSERT(bb, first, INSTR_CREATE_lea
(drcontext,
opnd_create_reg(reg_16),
opnd_create_base_disp(reg, DR_REG_NULL, 0,
sizeof(app_pc), OPSZ_lea)));
MINSERT(bb, first, INSTR_CREATE_mov_st
(drcontext,
opnd_create_far_base_disp(tls_seg, DR_REG_NULL, DR_REG_NULL,
0, tls_offs, OPSZ_PTR),
opnd_create_reg(reg)));
}
/* restore register if necessary */
if (steal)
dr_restore_reg(drcontext, bb, first, reg, SPILL_SLOT_1);
return DR_EMIT_DEFAULT;
}
/* instrument_instr is called whenever a memory reference is identified.
* It inserts code before the memory reference to to fill the memory buffer
* and jump to our own code cache to call the clean_call when the buffer is full.
*/
static void
instrument_instr(void *drcontext, instrlist_t *ilist, instr_t *where)
{
instr_t *instr, *call, *restore;
opnd_t opnd1, opnd2;
reg_id_t reg1, reg2;
drvector_t allowed;
per_thread_t *data;
app_pc pc;
data = drmgr_get_tls_field(drcontext, tls_index);
/* Steal two scratch registers.
* reg2 must be ECX or RCX for jecxz.
*/
drreg_init_and_fill_vector(&allowed, false);
drreg_set_vector_entry(&allowed, DR_REG_XCX, true);
if (drreg_reserve_register(drcontext, ilist, where, &allowed, ®2) !=
DRREG_SUCCESS ||
drreg_reserve_register(drcontext, ilist, where, NULL, ®1) != DRREG_SUCCESS) {
DR_ASSERT(false); /* cannot recover */
drvector_delete(&allowed);
return;
}
drvector_delete(&allowed);
/* The following assembly performs the following instructions
* buf_ptr->pc = pc;
* buf_ptr->opcode = opcode;
* buf_ptr++;
* if (buf_ptr >= buf_end_ptr)
* clean_call();
*/
drmgr_insert_read_tls_field(drcontext, tls_index, ilist, where, reg2);
/* Load data->buf_ptr into reg2 */
opnd1 = opnd_create_reg(reg2);
opnd2 = OPND_CREATE_MEMPTR(reg2, offsetof(per_thread_t, buf_ptr));
instr = INSTR_CREATE_mov_ld(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* Store pc */
pc = instr_get_app_pc(where);
/* For 64-bit, we can't use a 64-bit immediate so we split pc into two halves.
* We could alternatively load it into reg1 and then store reg1.
* We use a convenience routine that does the two-step store for us.
*/
opnd1 = OPND_CREATE_MEMPTR(reg2, offsetof(ins_ref_t, pc));
instrlist_insert_mov_immed_ptrsz(drcontext, (ptr_int_t) pc, opnd1,
ilist, where, NULL, NULL);
/* Store opcode */
opnd1 = OPND_CREATE_MEMPTR(reg2, offsetof(ins_ref_t, opcode));
opnd2 = OPND_CREATE_INT32(instr_get_opcode(where));
instr = INSTR_CREATE_mov_st(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* Increment reg value by pointer size using lea instr */
opnd1 = opnd_create_reg(reg2);
opnd2 = opnd_create_base_disp(reg2, DR_REG_NULL, 0, sizeof(ins_ref_t), OPSZ_lea);
instr = INSTR_CREATE_lea(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* Update the data->buf_ptr */
drmgr_insert_read_tls_field(drcontext, tls_index, ilist, where, reg1);
opnd1 = OPND_CREATE_MEMPTR(reg1, offsetof(per_thread_t, buf_ptr));
opnd2 = opnd_create_reg(reg2);
instr = INSTR_CREATE_mov_st(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* We use the lea + jecxz trick for better performance.
* lea and jecxz won't disturb the eflags, so we won't need
* code to save and restore the application's eflags.
*/
/* lea [reg2 - buf_end] => reg2 */
opnd1 = opnd_create_reg(reg1);
opnd2 = OPND_CREATE_MEMPTR(reg1, offsetof(per_thread_t, buf_end));
instr = INSTR_CREATE_mov_ld(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
opnd1 = opnd_create_reg(reg2);
opnd2 = opnd_create_base_disp(reg1, reg2, 1, 0, OPSZ_lea);
instr = INSTR_CREATE_lea(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* jecxz call */
call = INSTR_CREATE_label(drcontext);
opnd1 = opnd_create_instr(call);
instr = INSTR_CREATE_jecxz(drcontext, opnd1);
instrlist_meta_preinsert(ilist, where, instr);
/* jump restore to skip clean call */
restore = INSTR_CREATE_label(drcontext);
opnd1 = opnd_create_instr(restore);
instr = INSTR_CREATE_jmp(drcontext, opnd1);
instrlist_meta_preinsert(ilist, where, instr);
/* clean call */
/* We jump to our generated lean procedure which performs a full context
* switch and clean call invocation. This is to reduce the code cache size.
*/
instrlist_meta_preinsert(ilist, where, call);
/* mov restore DR_REG_XCX */
opnd1 = opnd_create_reg(reg2);
/* This is the return address for jumping back from the lean procedure. */
opnd2 = opnd_create_instr(restore);
/* We could use instrlist_insert_mov_instr_addr(), but with a register
* destination we know we can use a 64-bit immediate.
*/
instr = INSTR_CREATE_mov_imm(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* jmp code_cache */
opnd1 = opnd_create_pc(code_cache);
instr = INSTR_CREATE_jmp(drcontext, opnd1);
instrlist_meta_preinsert(ilist, where, instr);
/* Restore scratch registers */
instrlist_meta_preinsert(ilist, where, restore);
if (drreg_unreserve_register(drcontext, ilist, where, reg1) != DRREG_SUCCESS ||
drreg_unreserve_register(drcontext, ilist, where, reg2) != DRREG_SUCCESS)
DR_ASSERT(false);
}
/*
* instrument_mem is called whenever a memory reference is identified.
* It inserts code before the memory reference to to fill the memory buffer
* and jump to our own code cache to call the clean_call when the buffer is full.
*/
static void
instrument_mem(void *drcontext, instrlist_t *ilist, instr_t *where,
int pos, bool write)
{
instr_t *instr, *call, *restore, *first, *second;
opnd_t ref, opnd1, opnd2;
reg_id_t reg1 = DR_REG_XBX; /* We can optimize it by picking dead reg */
reg_id_t reg2 = DR_REG_XCX; /* reg2 must be ECX or RCX for jecxz */
per_thread_t *data;
app_pc pc;
data = drmgr_get_tls_field(drcontext, tls_index);
/* Steal the register for memory reference address *
* We can optimize away the unnecessary register save and restore
* by analyzing the code and finding the register is dead.
*/
dr_save_reg(drcontext, ilist, where, reg1, SPILL_SLOT_2);
dr_save_reg(drcontext, ilist, where, reg2, SPILL_SLOT_3);
if (write)
ref = instr_get_dst(where, pos);
else
ref = instr_get_src(where, pos);
/* use drutil to get mem address */
drutil_insert_get_mem_addr(drcontext, ilist, where, ref, reg1, reg2);
/* The following assembly performs the following instructions
* buf_ptr->write = write;
* buf_ptr->addr = addr;
* buf_ptr->size = size;
* buf_ptr->pc = pc;
* buf_ptr++;
* if (buf_ptr >= buf_end_ptr)
* clean_call();
*/
drmgr_insert_read_tls_field(drcontext, tls_index, ilist, where, reg2);
/* Load data->buf_ptr into reg2 */
opnd1 = opnd_create_reg(reg2);
opnd2 = OPND_CREATE_MEMPTR(reg2, offsetof(per_thread_t, buf_ptr));
instr = INSTR_CREATE_mov_ld(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* Move write/read to write field */
opnd1 = OPND_CREATE_MEM32(reg2, offsetof(mem_ref_t, write));
opnd2 = OPND_CREATE_INT32(write);
instr = INSTR_CREATE_mov_imm(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* Store address in memory ref */
opnd1 = OPND_CREATE_MEMPTR(reg2, offsetof(mem_ref_t, addr));
opnd2 = opnd_create_reg(reg1);
instr = INSTR_CREATE_mov_st(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* Store size in memory ref */
opnd1 = OPND_CREATE_MEMPTR(reg2, offsetof(mem_ref_t, size));
/* drutil_opnd_mem_size_in_bytes handles OP_enter */
opnd2 = OPND_CREATE_INT32(drutil_opnd_mem_size_in_bytes(ref, where));
instr = INSTR_CREATE_mov_st(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* Store pc in memory ref */
pc = instr_get_app_pc(where);
/* For 64-bit, we can't use a 64-bit immediate so we split pc into two halves.
* We could alternatively load it into reg1 and then store reg1.
* We use a convenience routine that does the two-step store for us.
*/
opnd1 = OPND_CREATE_MEMPTR(reg2, offsetof(mem_ref_t, pc));
instrlist_insert_mov_immed_ptrsz(drcontext, (ptr_int_t) pc, opnd1,
ilist, where, &first, &second);
instr_set_ok_to_mangle(first, false/*meta*/);
if (second != NULL)
instr_set_ok_to_mangle(second, false/*meta*/);
/* Increment reg value by pointer size using lea instr */
opnd1 = opnd_create_reg(reg2);
opnd2 = opnd_create_base_disp(reg2, DR_REG_NULL, 0,
sizeof(mem_ref_t),
OPSZ_lea);
instr = INSTR_CREATE_lea(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* Update the data->buf_ptr */
drmgr_insert_read_tls_field(drcontext, tls_index, ilist, where, reg1);
opnd1 = OPND_CREATE_MEMPTR(reg1, offsetof(per_thread_t, buf_ptr));
opnd2 = opnd_create_reg(reg2);
instr = INSTR_CREATE_mov_st(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* we use lea + jecxz trick for better performance
* lea and jecxz won't disturb the eflags, so we won't insert
* code to save and restore application's eflags.
*/
/* lea [reg2 - buf_end] => reg2 */
opnd1 = opnd_create_reg(reg1);
opnd2 = OPND_CREATE_MEMPTR(reg1, offsetof(per_thread_t, buf_end));
instr = INSTR_CREATE_mov_ld(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
opnd1 = opnd_create_reg(reg2);
opnd2 = opnd_create_base_disp(reg1, reg2, 1, 0, OPSZ_lea);
instr = INSTR_CREATE_lea(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* jecxz call */
call = INSTR_CREATE_label(drcontext);
opnd1 = opnd_create_instr(call);
instr = INSTR_CREATE_jecxz(drcontext, opnd1);
instrlist_meta_preinsert(ilist, where, instr);
/* jump restore to skip clean call */
restore = INSTR_CREATE_label(drcontext);
opnd1 = opnd_create_instr(restore);
instr = INSTR_CREATE_jmp(drcontext, opnd1);
instrlist_meta_preinsert(ilist, where, instr);
/* clean call */
/* We jump to lean procedure which performs full context switch and
* clean call invocation. This is to reduce the code cache size.
*/
instrlist_meta_preinsert(ilist, where, call);
/* mov restore DR_REG_XCX */
opnd1 = opnd_create_reg(reg2);
/* this is the return address for jumping back from lean procedure */
opnd2 = opnd_create_instr(restore);
/* We could use instrlist_insert_mov_instr_addr(), but with a register
* destination we know we can use a 64-bit immediate.
*/
instr = INSTR_CREATE_mov_imm(drcontext, opnd1, opnd2);
instrlist_meta_preinsert(ilist, where, instr);
/* jmp code_cache */
opnd1 = opnd_create_pc(code_cache);
instr = INSTR_CREATE_jmp(drcontext, opnd1);
instrlist_meta_preinsert(ilist, where, instr);
/* restore %reg */
instrlist_meta_preinsert(ilist, where, restore);
dr_restore_reg(drcontext, ilist, where, reg1, SPILL_SLOT_2);
dr_restore_reg(drcontext, ilist, where, reg2, SPILL_SLOT_3);
}
/** 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;
}
