/*
* mono_local_cprop:
*
* A combined local copy and constant propagation pass.
*/
void
mono_local_cprop (MonoCompile *cfg)
{
MonoBasicBlock *bb;
MonoInst **defs;
gint32 *def_index;
int max;
restart:
max = cfg->next_vreg;
defs = mono_mempool_alloc (cfg->mempool, sizeof (MonoInst*) * (cfg->next_vreg + 1));
def_index = mono_mempool_alloc (cfg->mempool, sizeof (guint32) * (cfg->next_vreg + 1));
for (bb = cfg->bb_entry; bb; bb = bb->next_bb) {
MonoInst *ins;
int ins_index;
int last_call_index;
/* Manually init the defs entries used by the bblock */
MONO_BB_FOR_EACH_INS (bb, ins) {
int sregs [MONO_MAX_SRC_REGS];
int num_sregs, i;
if ((ins->dreg != -1) && (ins->dreg < max)) {
defs [ins->dreg] = NULL;
#if SIZEOF_REGISTER == 4
defs [ins->dreg + 1] = NULL;
#endif
}
num_sregs = mono_inst_get_src_registers (ins, sregs);
for (i = 0; i < num_sregs; ++i) {
int sreg = sregs [i];
if (sreg < max) {
defs [sreg] = NULL;
#if SIZEOF_REGISTER == 4
defs [sreg + 1] = NULL;
#endif
}
}
}
ins_index = 0;
last_call_index = -1;
MONO_BB_FOR_EACH_INS (bb, ins) {
const char *spec = INS_INFO (ins->opcode);
int regtype, srcindex, sreg;
int num_sregs;
int sregs [MONO_MAX_SRC_REGS];
if (ins->opcode == OP_NOP) {
MONO_DELETE_INS (bb, ins);
continue;
}
g_assert (ins->opcode > MONO_CEE_LAST);
/* FIXME: Optimize this */
if (ins->opcode == OP_LDADDR) {
MonoInst *var = ins->inst_p0;
defs [var->dreg] = NULL;
/*
if (!MONO_TYPE_ISSTRUCT (var->inst_vtype))
break;
*/
}
if (MONO_IS_STORE_MEMBASE (ins)) {
sreg = ins->dreg;
regtype = 'i';
if ((regtype == 'i') && (sreg != -1) && defs [sreg]) {
MonoInst *def = defs [sreg];
if ((def->opcode == OP_MOVE) && (!defs [def->sreg1] || (def_index [def->sreg1] < def_index [sreg])) && !vreg_is_volatile (cfg, def->sreg1)) {
int vreg = def->sreg1;
if (cfg->verbose_level > 2) printf ("CCOPY: R%d -> R%d\n", sreg, vreg);
ins->dreg = vreg;
}
}
}
num_sregs = mono_inst_get_src_registers (ins, sregs);
for (srcindex = 0; srcindex < num_sregs; ++srcindex) {
MonoInst *def;
int nregs;
nregs = mono_inst_get_src_registers (ins, sregs);
regtype = spec [MONO_INST_SRC1 + srcindex];
sreg = sregs [srcindex];
if ((regtype == ' ') || (sreg == -1) || (!defs [sreg]))
continue;
def = defs [sreg];
/* Copy propagation */
/*
* The first check makes sure the source of the copy did not change since
* the copy was made.
* The second check avoids volatile variables.
* The third check avoids copy propagating local vregs through a call,
* since the lvreg will be spilled
* The fourth check avoids copy propagating a vreg in cases where
* it would be eliminated anyway by reverse copy propagation later,
* because propagating it would create another use for it, thus making
* it impossible to use reverse copy propagation.
*/
/* Enabling this for floats trips up the fp stack */
/*
* Enabling this for floats on amd64 seems to cause a failure in
* basic-math.cs, most likely because it gets rid of some r8->r4
* conversions.
*/
if (MONO_IS_MOVE (def) &&
(!defs [def->sreg1] || (def_index [def->sreg1] < def_index [sreg])) &&
!vreg_is_volatile (cfg, def->sreg1) &&
/* This avoids propagating local vregs across calls */
((get_vreg_to_inst (cfg, def->sreg1) || !defs [def->sreg1] || (def_index [def->sreg1] >= last_call_index) || (def->opcode == OP_VMOVE))) &&
!(defs [def->sreg1] && mono_inst_next (defs [def->sreg1], FILTER_IL_SEQ_POINT) == def) &&
(!MONO_ARCH_USE_FPSTACK || (def->opcode != OP_FMOVE)) &&
(def->opcode != OP_FMOVE)) {
int vreg = def->sreg1;
if (cfg->verbose_level > 2) printf ("CCOPY/2: R%d -> R%d\n", sreg, vreg);
sregs [srcindex] = vreg;
mono_inst_set_src_registers (ins, sregs);
/* Allow further iterations */
srcindex = -1;
continue;
}
/* Constant propagation */
/* FIXME: Make is_inst_imm a macro */
/* FIXME: Make is_inst_imm take an opcode argument */
/* is_inst_imm is only needed for binops */
if ((((def->opcode == OP_ICONST) || ((sizeof (gpointer) == 8) && (def->opcode == OP_I8CONST))) &&
(((srcindex == 0) && (ins->sreg2 == -1)) || mono_arch_is_inst_imm (def->inst_c0))) ||
(!MONO_ARCH_USE_FPSTACK && (def->opcode == OP_R8CONST))) {
guint32 opcode2;
/* srcindex == 1 -> binop, ins->sreg2 == -1 -> unop */
if ((srcindex == 1) && (ins->sreg1 != -1) && defs [ins->sreg1] && (defs [ins->sreg1]->opcode == OP_ICONST) && defs [ins->sreg2]) {
/* Both arguments are constants, perform cfold */
mono_constant_fold_ins (cfg, ins, defs [ins->sreg1], defs [ins->sreg2], TRUE);
} else if ((srcindex == 0) && (ins->sreg2 != -1) && defs [ins->sreg2]) {
/* Arg 1 is constant, swap arguments if possible */
int opcode = ins->opcode;
mono_constant_fold_ins (cfg, ins, defs [ins->sreg1], defs [ins->sreg2], TRUE);
if (ins->opcode != opcode) {
/* Allow further iterations */
srcindex = -1;
continue;
}
} else if ((srcindex == 0) && (ins->sreg2 == -1)) {
/* Constant unop, perform cfold */
mono_constant_fold_ins (cfg, ins, defs [ins->sreg1], NULL, TRUE);
}
opcode2 = mono_op_to_op_imm (ins->opcode);
if ((opcode2 != -1) && mono_arch_is_inst_imm (def->inst_c0) && ((srcindex == 1) || (ins->sreg2 == -1))) {
ins->opcode = opcode2;
if ((def->opcode == OP_I8CONST) && (sizeof (gpointer) == 4)) {
ins->inst_ls_word = def->inst_ls_word;
ins->inst_ms_word = def->inst_ms_word;
} else {
ins->inst_imm = def->inst_c0;
}
sregs [srcindex] = -1;
mono_inst_set_src_registers (ins, sregs);
if ((opcode2 == OP_VOIDCALL) || (opcode2 == OP_CALL) || (opcode2 == OP_LCALL) || (opcode2 == OP_FCALL))
((MonoCallInst*)ins)->fptr = (gpointer)ins->inst_imm;
/* Allow further iterations */
srcindex = -1;
continue;
}
else {
/* Special cases */
#if defined(TARGET_X86) || defined(TARGET_AMD64)
if ((ins->opcode == OP_X86_LEA) && (srcindex == 1)) {
#if SIZEOF_REGISTER == 8
/* FIXME: Use OP_PADD_IMM when the new JIT is done */
ins->opcode = OP_LADD_IMM;
#else
ins->opcode = OP_ADD_IMM;
#endif
ins->inst_imm += def->inst_c0 << ins->backend.shift_amount;
ins->sreg2 = -1;
}
#endif
opcode2 = mono_load_membase_to_load_mem (ins->opcode);
if ((srcindex == 0) && (opcode2 != -1) && mono_arch_is_inst_imm (def->inst_c0)) {
ins->opcode = opcode2;
ins->inst_imm = def->inst_c0 + ins->inst_offset;
ins->sreg1 = -1;
}
}
}
else if (((def->opcode == OP_ADD_IMM) || (def->opcode == OP_LADD_IMM)) && (MONO_IS_LOAD_MEMBASE (ins) || MONO_ARCH_IS_OP_MEMBASE (ins->opcode))) {
/* ADD_IMM is created by spill_global_vars */
/*
* We have to guarantee that def->sreg1 haven't changed since def->dreg
* was defined. cfg->frame_reg is assumed to remain constant.
*/
if ((def->sreg1 == cfg->frame_reg) || ((def->next == ins) && (def->dreg != def->sreg1))) {
ins->inst_basereg = def->sreg1;
ins->inst_offset += def->inst_imm;
}
} else if ((ins->opcode == OP_ISUB_IMM) && (def->opcode == OP_IADD_IMM) && (def->next == ins) && (def->dreg != def->sreg1)) {
ins->sreg1 = def->sreg1;
ins->inst_imm -= def->inst_imm;
} else if ((ins->opcode == OP_IADD_IMM) && (def->opcode == OP_ISUB_IMM) && (def->next == ins) && (def->dreg != def->sreg1)) {
ins->sreg1 = def->sreg1;
ins->inst_imm -= def->inst_imm;
} else if (ins->opcode == OP_STOREI1_MEMBASE_REG &&
(def->opcode == OP_ICONV_TO_U1 || def->opcode == OP_ICONV_TO_I1 || def->opcode == OP_SEXT_I4 || (SIZEOF_REGISTER == 8 && def->opcode == OP_LCONV_TO_U1)) &&
(!defs [def->sreg1] || (def_index [def->sreg1] < def_index [sreg]))) {
/* Avoid needless sign extension */
ins->sreg1 = def->sreg1;
} else if (ins->opcode == OP_STOREI2_MEMBASE_REG &&
(def->opcode == OP_ICONV_TO_U2 || def->opcode == OP_ICONV_TO_I2 || def->opcode == OP_SEXT_I4 || (SIZEOF_REGISTER == 8 && def->opcode == OP_LCONV_TO_I2)) &&
(!defs [def->sreg1] || (def_index [def->sreg1] < def_index [sreg]))) {
/* Avoid needless sign extension */
ins->sreg1 = def->sreg1;
}
}
/* Do strength reduction here */
/* FIXME: Add long/float */
switch (ins->opcode) {
case OP_MOVE:
case OP_XMOVE:
if (ins->dreg == ins->sreg1) {
MONO_DELETE_INS (bb, ins);
spec = INS_INFO (ins->opcode);
}
break;
case OP_ADD_IMM:
case OP_IADD_IMM:
case OP_SUB_IMM:
case OP_ISUB_IMM:
#if SIZEOF_REGISTER == 8
case OP_LADD_IMM:
case OP_LSUB_IMM:
#endif
if (ins->inst_imm == 0) {
ins->opcode = OP_MOVE;
spec = INS_INFO (ins->opcode);
}
break;
case OP_MUL_IMM:
case OP_IMUL_IMM:
#if SIZEOF_REGISTER == 8
case OP_LMUL_IMM:
#endif
if (ins->inst_imm == 0) {
ins->opcode = (ins->opcode == OP_LMUL_IMM) ? OP_I8CONST : OP_ICONST;
ins->inst_c0 = 0;
ins->sreg1 = -1;
} else if (ins->inst_imm == 1) {
ins->opcode = OP_MOVE;
} else if ((ins->opcode == OP_IMUL_IMM) && (ins->inst_imm == -1)) {
ins->opcode = OP_INEG;
} else if ((ins->opcode == OP_LMUL_IMM) && (ins->inst_imm == -1)) {
ins->opcode = OP_LNEG;
} else {
int power2 = mono_is_power_of_two (ins->inst_imm);
if (power2 >= 0) {
ins->opcode = (ins->opcode == OP_MUL_IMM) ? OP_SHL_IMM : ((ins->opcode == OP_LMUL_IMM) ? OP_LSHL_IMM : OP_ISHL_IMM);
ins->inst_imm = power2;
}
}
spec = INS_INFO (ins->opcode);
break;
case OP_IREM_UN_IMM:
case OP_IDIV_UN_IMM: {
int c = ins->inst_imm;
int power2 = mono_is_power_of_two (c);
if (power2 >= 0) {
if (ins->opcode == OP_IREM_UN_IMM) {
ins->opcode = OP_IAND_IMM;
ins->sreg2 = -1;
ins->inst_imm = (1 << power2) - 1;
} else if (ins->opcode == OP_IDIV_UN_IMM) {
ins->opcode = OP_ISHR_UN_IMM;
ins->sreg2 = -1;
ins->inst_imm = power2;
}
}
spec = INS_INFO (ins->opcode);
break;
}
case OP_IDIV_IMM: {
int c = ins->inst_imm;
int power2 = mono_is_power_of_two (c);
MonoInst *tmp1, *tmp2, *tmp3, *tmp4;
/* FIXME: Move this elsewhere cause its hard to implement it here */
if (power2 == 1) {
int r1 = mono_alloc_ireg (cfg);
NEW_BIALU_IMM (cfg, tmp1, OP_ISHR_UN_IMM, r1, ins->sreg1, 31);
mono_bblock_insert_after_ins (bb, ins, tmp1);
NEW_BIALU (cfg, tmp2, OP_IADD, r1, r1, ins->sreg1);
mono_bblock_insert_after_ins (bb, tmp1, tmp2);
NEW_BIALU_IMM (cfg, tmp3, OP_ISHR_IMM, ins->dreg, r1, 1);
mono_bblock_insert_after_ins (bb, tmp2, tmp3);
NULLIFY_INS (ins);
// We allocated a new vreg, so need to restart
goto restart;
} else if (power2 > 0) {
int r1 = mono_alloc_ireg (cfg);
NEW_BIALU_IMM (cfg, tmp1, OP_ISHR_IMM, r1, ins->sreg1, 31);
mono_bblock_insert_after_ins (bb, ins, tmp1);
NEW_BIALU_IMM (cfg, tmp2, OP_ISHR_UN_IMM, r1, r1, (32 - power2));
mono_bblock_insert_after_ins (bb, tmp1, tmp2);
NEW_BIALU (cfg, tmp3, OP_IADD, r1, r1, ins->sreg1);
mono_bblock_insert_after_ins (bb, tmp2, tmp3);
NEW_BIALU_IMM (cfg, tmp4, OP_ISHR_IMM, ins->dreg, r1, power2);
mono_bblock_insert_after_ins (bb, tmp3, tmp4);
NULLIFY_INS (ins);
// We allocated a new vreg, so need to restart
goto restart;
}
break;
}
}
if (spec [MONO_INST_DEST] != ' ') {
MonoInst *def = defs [ins->dreg];
if (def && (def->opcode == OP_ADD_IMM) && (def->sreg1 == cfg->frame_reg) && (MONO_IS_STORE_MEMBASE (ins))) {
/* ADD_IMM is created by spill_global_vars */
/* cfg->frame_reg is assumed to remain constant */
ins->inst_destbasereg = def->sreg1;
ins->inst_offset += def->inst_imm;
}
}
if ((spec [MONO_INST_DEST] != ' ') && !MONO_IS_STORE_MEMBASE (ins) && !vreg_is_volatile (cfg, ins->dreg)) {
defs [ins->dreg] = ins;
def_index [ins->dreg] = ins_index;
}
if (MONO_IS_CALL (ins))
last_call_index = ins_index;
ins_index ++;
}
}
/*
* Process a BB removing bounds checks from array accesses.
* It does the following (in sequence):
* - Get the BB entry condition
* - Add its relations to the relation graph in the evaluation area
* - Process all the MonoInst trees in the BB
* - Recursively process all the children BBs in the dominator tree
* - Remove the relations previously added to the relation graph
*
* bb: the BB that must be processed
* area: the current evaluation area (it contains the relation graph and
* memory for all the evaluation contexts is already allocated)
*/
static void
process_block (MonoCompile *cfg, MonoBasicBlock *bb, MonoVariableRelationsEvaluationArea *area) {
int inst_index;
MonoInst *ins;
MonoAdditionalVariableRelationsForBB additional_relations;
GSList *dominated_bb, *l;
GSList *check_relations = NULL;
if (TRACE_ABC_REMOVAL) {
printf ("\nProcessing block %d [dfn %d]...\n", bb->block_num, bb->dfn);
}
if (bb->region != -1)
return;
get_relations_from_previous_bb (area, bb, &additional_relations);
if (TRACE_ABC_REMOVAL) {
if (additional_relations.relation1.relation.relation != MONO_ANY_RELATION) {
printf ("Adding relation 1 on variable %d: ", additional_relations.relation1.variable);
print_summarized_value_relation (&(additional_relations.relation1.relation));
printf ("\n");
}
if (additional_relations.relation2.relation.relation != MONO_ANY_RELATION) {
printf ("Adding relation 2 on variable %d: ", additional_relations.relation2.variable);
print_summarized_value_relation (&(additional_relations.relation2.relation));
printf ("\n");
}
}
apply_change_to_evaluation_area (area, &(additional_relations.relation1));
apply_change_to_evaluation_area (area, &(additional_relations.relation2));
inst_index = 0;
for (ins = bb->code; ins; ins = ins->next) {
MonoAdditionalVariableRelation *rel;
int array_var, index_var;
if (TRACE_ABC_REMOVAL) {
printf ("Processing instruction %d\n", inst_index);
inst_index++;
}
if (ins->opcode == OP_BOUNDS_CHECK) { /* Handle OP_LDELEMA2D, too */
if (TRACE_ABC_REMOVAL) {
printf ("Attempting check removal...\n");
}
array_var = ins->sreg1;
index_var = ins->sreg2;
remove_abc_from_inst (ins, area);
/* We can derive additional relations from the bounds check */
if (ins->opcode != OP_NOP) {
rel = mono_mempool_alloc0 (cfg->mempool, sizeof (MonoAdditionalVariableRelation));
rel->variable = index_var;
rel->relation.relation = MONO_LT_RELATION;
rel->relation.related_value.type = MONO_VARIABLE_SUMMARIZED_VALUE;
rel->relation.related_value.value.variable.variable = array_var;
rel->relation.related_value.value.variable.delta = 0;
apply_change_to_evaluation_area (area, rel);
check_relations = g_slist_append_mempool (cfg->mempool, check_relations, rel);
rel = mono_mempool_alloc0 (cfg->mempool, sizeof (MonoAdditionalVariableRelation));
rel->variable = index_var;
rel->relation.relation = MONO_GE_RELATION;
rel->relation.related_value.type = MONO_CONSTANT_SUMMARIZED_VALUE;
rel->relation.related_value.value.constant.value = 0;
apply_change_to_evaluation_area (area, rel);
check_relations = g_slist_append_mempool (cfg->mempool, check_relations, rel);
}
}
if (ins->opcode == OP_CHECK_THIS) {
if (eval_non_null (area, ins->sreg1)) {
if (REPORT_ABC_REMOVAL)
printf ("ARRAY-ACCESS: removed check_this instruction.\n");
NULLIFY_INS (ins);
}
}
if (ins->opcode == OP_NOT_NULL)
add_non_null (area, cfg, ins->sreg1, &check_relations);
/*
* This doesn't work because LLVM can move the non-faulting loads before the faulting
* ones (test_0_llvm_moving_faulting_loads ()).
* FIXME: This also doesn't work because abcrem equates an array with its length,
* so a = new int [100] implies a != null, but a = new int [0] doesn't.
*/
#if 0
/*
* Eliminate MONO_INST_FAULT flags if possible.
*/
if (COMPILE_LLVM (cfg) && (ins->opcode == OP_LDLEN ||
ins->opcode == OP_BOUNDS_CHECK ||
ins->opcode == OP_STRLEN ||
(MONO_IS_LOAD_MEMBASE (ins) && (ins->flags & MONO_INST_FAULT)) ||
(MONO_IS_STORE_MEMBASE (ins) && (ins->flags & MONO_INST_FAULT)))) {
int reg;
if (MONO_IS_STORE_MEMBASE (ins))
reg = ins->inst_destbasereg;
else if (MONO_IS_LOAD_MEMBASE (ins))
reg = ins->inst_basereg;
else
reg = ins->sreg1;
if (eval_non_null (area, reg)) {
if (REPORT_ABC_REMOVAL)
printf ("ARRAY-ACCESS: removed MONO_INST_FAULT flag.\n");
ins->flags &= ~MONO_INST_FAULT;
} else {
add_non_null (area, cfg, reg, &check_relations);
}
}
#endif
}
if (TRACE_ABC_REMOVAL) {
printf ("Processing block %d [dfn %d] done.\n", bb->block_num, bb->dfn);
}
for (dominated_bb = bb->dominated; dominated_bb != NULL; dominated_bb = dominated_bb->next) {
process_block (cfg, (MonoBasicBlock*) (dominated_bb->data), area);
}
for (l = check_relations; l; l = l->next)
remove_change_from_evaluation_area (l->data);
remove_change_from_evaluation_area (&(additional_relations.relation1));
remove_change_from_evaluation_area (&(additional_relations.relation2));
}