* Patrik Torstensson (Patrik.Torstesson at gmail.com)
*
* (C) 2005 Ximian, Inc. http://www.ximian.com
+ * Copyright 2011 Xamarin Inc. http://www.xamarin.com
*/
#include "mini.h"
#ifndef DISABLE_JIT
- /*
+
+/*
+ * Returns true if @bb is a basic block which falls through the next block.
+ * TODO verify if it helps to check if the bb last ins is a branch to its successor.
+ */
+static gboolean
+mono_bb_is_fall_through (MonoCompile *cfg, MonoBasicBlock *bb)
+{
+ return bb->next_bb && bb->next_bb->region == bb->region && /*fall throught between regions is not really interesting or useful*/
+ (bb->last_ins == NULL || !MONO_IS_BRANCH_OP (bb->last_ins)); /*and the last op can't be a branch too*/
+}
+
+/*
* Used by the arch code to replace the exception handling
* with a direct branch. This is safe to do if the
* exception object isn't used, no rethrow statement and
MonoInst *
mono_branch_optimize_exception_target (MonoCompile *cfg, MonoBasicBlock *bb, const char * exname)
{
- MonoMethod *method = cfg->method;
- MonoMethodHeader *header = mono_method_get_header (method);
+ MonoMethodHeader *header = cfg->header;
MonoExceptionClause *clause;
MonoClass *exclass;
int i;
return jump;
}
+ return NULL;
+ } else {
+ /* Branching to an outer clause could skip inner clauses */
return NULL;
}
} else {
OP_CMOV_LGT_UN
};
-static int
+static G_GNUC_UNUSED int
br_to_br_un (int opcode)
{
switch (opcode) {
bb2 = bb->out_bb [1];
if (bb1->in_count == 1 && bb2->in_count == 1 && bb1->out_count == 1 && bb2->out_count == 1 && bb1->out_bb [0] == bb2->out_bb [0]) {
- MonoInst *prev, *compare, *branch, *ins1, *ins2, *cmov, *move, *tmp;
+ MonoInst *compare, *branch, *ins1, *ins2, *cmov, *move, *tmp;
MonoBasicBlock *true_bb, *false_bb;
gboolean simple, ret;
int dreg, tmp_reg;
continue;
/* Find the compare instruction */
- /* FIXME: Optimize this using prev */
- prev = NULL;
- compare = bb->code;
- g_assert (compare);
- while (compare->next && !MONO_IS_COND_BRANCH_OP (compare->next)) {
- prev = compare;
- compare = compare->next;
- }
- g_assert (compare->next && MONO_IS_COND_BRANCH_OP (compare->next));
- branch = compare->next;
+ if (!bb->last_ins || !bb->last_ins->prev)
+ continue;
+ branch = bb->last_ins;
+ compare = branch->prev;
+
+ if (!MONO_IS_COND_BRANCH_OP (branch))
+ /* This can happen if a cond branch is optimized away */
+ continue;
true_bb = branch->inst_true_bb;
false_bb = branch->inst_false_bb;
if ((bb2->in_count == 1 && bb2->out_count == 1 && bb2->out_bb [0] == bb1) ||
(bb1->in_count == 1 && bb1->out_count == 1 && bb1->out_bb [0] == bb2)) {
- MonoInst *prev, *compare, *branch, *ins1, *cmov, *tmp;
+ MonoInst *compare, *branch, *ins1, *cmov, *tmp;
gboolean simple;
int dreg, tmp_reg;
CompType comp_type;
continue;
/* Find the compare instruction */
- /* FIXME: Optimize this using prev */
- prev = NULL;
- compare = bb->code;
- g_assert (compare);
- while (compare->next && !MONO_IS_COND_BRANCH_OP (compare->next)) {
- prev = compare;
- compare = compare->next;
- }
- g_assert (compare->next && MONO_IS_COND_BRANCH_OP (compare->next));
- branch = compare->next;
+
+ if (!bb->last_ins || !bb->last_ins->prev)
+ continue;
+ branch = bb->last_ins;
+ compare = branch->prev;
+
+ if (!MONO_IS_COND_BRANCH_OP (branch))
+ /* This can happen if a cond branch is optimized away */
+ continue;
/* FIXME: */
comp_type = mono_opcode_to_type (branch->opcode, compare->opcode);
if (cfg->ret && ins1->dreg == cfg->ret->dreg)
continue;
+ if (!(cfg->opt & MONO_OPT_DEADCE))
+ /*
+ * It is possible that dreg is never set before, so we can't use
+ * it as an sreg of the cmov instruction (#582322).
+ */
+ continue;
+
if (cfg->verbose_level > 2) {
printf ("\tBranch -> CMove optimization (2) in BB%d on\n", bb->block_num);
printf ("\t\t"); mono_print_ins (compare);
if ((bb->out_bb [0]->in_count == 1) && (bb->out_bb [0] != cfg->bb_exit) &&
(bb->region == bb->out_bb [0]->region)) {
mono_merge_basic_blocks (cfg, bb, bb->out_bb [0]);
+
+ /*
+ * bbn might have fallen through to the next bb without a branch,
+ * have to add one now (#474718).
+ * FIXME: Maybe need to do this more generally in
+ * merge_basic_blocks () ?
+ */
+ if (!(bb->last_ins && MONO_IS_BRANCH_OP (bb->last_ins)) && bb->out_count) {
+ MONO_INST_NEW (cfg, ins1, OP_BR);
+ ins1->inst_target_bb = bb->out_bb [0];
+ MONO_ADD_INS (bb, ins1);
+ }
goto restart;
}
}
/* Merging bblocks could make some variables local */
mono_handle_global_vregs (cfg);
if (cfg->opt & (MONO_OPT_CONSPROP | MONO_OPT_COPYPROP))
- mono_local_cprop2 (cfg);
- mono_local_deadce (cfg);
+ mono_local_cprop (cfg);
+ if (cfg->opt & MONO_OPT_DEADCE)
+ mono_local_deadce (cfg);
}
#endif
}
static void
replace_out_block_in_code (MonoBasicBlock *bb, MonoBasicBlock *orig, MonoBasicBlock *repl) {
MonoInst *ins;
+
+#if defined(__native_client_codegen__)
+ /* Need to maintain this flag for the new block because */
+ /* we can't jump indirectly to a non-aligned block. */
+ if (orig->flags & BB_INDIRECT_JUMP_TARGET)
+ {
+ repl->flags |= BB_INDIRECT_JUMP_TARGET;
+ }
+#endif
for (ins = bb->code; ins != NULL; ins = ins->next) {
switch (ins->opcode) {
}
mono_unlink_bblock (cfg, bb, target_bb);
-
- if ((previous_bb != cfg->bb_entry) &&
- (previous_bb->region == bb->region) &&
- ((previous_bb->last_ins == NULL) ||
- (!MONO_IS_BRANCH_OP (previous_bb->last_ins)))) {
+ if (previous_bb != cfg->bb_entry && mono_bb_is_fall_through (cfg, previous_bb)) {
for (i = 0; i < previous_bb->out_count; i++) {
if (previous_bb->out_bb [i] == target_bb) {
MonoInst *jump;
bb->has_array_access |= bbn->has_array_access;
bb->extended |= bbn->extended;
+ /* Compute prev_bb if possible to avoid the linear search below */
+ prev_bb = NULL;
+ for (i = 0; i < bbn->in_count; ++i)
+ if (bbn->in_bb [0]->next_bb == bbn)
+ prev_bb = bbn->in_bb [0];
+
mono_unlink_bblock (cfg, bb, bbn);
for (i = 0; i < bbn->out_count; ++i)
mono_link_bblock (cfg, bb, bbn->out_bb [i]);
mono_unlink_bblock (cfg, bbn, bbn->out_bb [0]);
/* Handle the branch at the end of the bb */
- for (inst = bb->code; inst != NULL; inst = inst->next) {
- if (inst->opcode == OP_CALL_HANDLER) {
- g_assert (inst->inst_target_bb == bbn);
- NULLIFY_INS (inst);
+ if (bb->has_call_handler) {
+ for (inst = bb->code; inst != NULL; inst = inst->next) {
+ if (inst->opcode == OP_CALL_HANDLER) {
+ g_assert (inst->inst_target_bb == bbn);
+ NULLIFY_INS (inst);
+ }
}
- if (MONO_IS_JUMP_TABLE (inst)) {
- int i;
- MonoJumpInfoBBTable *table = MONO_JUMP_TABLE_FROM_INS (inst);
- for (i = 0; i < table->table_size; i++ ) {
- /* Might be already NULL from a previous merge */
- if (table->table [i])
- g_assert (table->table [i] == bbn);
- table->table [i] = NULL;
+ }
+ if (bb->has_jump_table) {
+ for (inst = bb->code; inst != NULL; inst = inst->next) {
+ if (MONO_IS_JUMP_TABLE (inst)) {
+ int i;
+ MonoJumpInfoBBTable *table = MONO_JUMP_TABLE_FROM_INS (inst);
+ for (i = 0; i < table->table_size; i++ ) {
+ /* Might be already NULL from a previous merge */
+ if (table->table [i])
+ g_assert (table->table [i] == bbn);
+ table->table [i] = NULL;
+ }
+ /* Can't nullify this as later instructions depend on it */
}
- /* Can't nullify this as later instructions depend on it */
}
}
if (bb->last_ins && MONO_IS_COND_BRANCH_OP (bb->last_ins)) {
NULLIFY_INS (bb->last_ins);
}
+ bb->has_call_handler |= bbn->has_call_handler;
+ bb->has_jump_table |= bbn->has_jump_table;
+
if (bb->last_ins) {
if (bbn->code) {
bb->last_ins->next = bbn->code;
bb->code = bbn->code;
bb->last_ins = bbn->last_ins;
}
- for (prev_bb = cfg->bb_entry; prev_bb && prev_bb->next_bb != bbn; prev_bb = prev_bb->next_bb)
- ;
+
+ if (!prev_bb) {
+ for (prev_bb = cfg->bb_entry; prev_bb && prev_bb->next_bb != bbn; prev_bb = prev_bb->next_bb)
+ ;
+ }
if (prev_bb) {
prev_bb->next_bb = bbn->next_bb;
} else {
bb->next_bb = bbn->next_bb;
}
mono_nullify_basic_block (bbn);
+
+ /*
+ * If bbn fell through to its next bblock, have to add a branch, since bb
+ * will not fall though to the same bblock (#513931).
+ */
+ if (bb->last_ins && bb->out_count == 1 && bb->out_bb [0] != bb->next_bb && !MONO_IS_BRANCH_OP (bb->last_ins)) {
+ MONO_INST_NEW (cfg, inst, OP_BR);
+ inst->inst_target_bb = bb->out_bb [0];
+ MONO_ADD_INS (bb, inst);
+ }
}
static void
printf (")");
if (bb->last_ins != NULL) {
printf (" ");
- mono_print_tree (bb->last_ins);
+ mono_print_ins (bb->last_ins);
}
printf ("\n");
}
int in_bb_index;
for (in_bb_index = 0; in_bb_index < bb->in_count; in_bb_index++) {
MonoBasicBlock *in_bb = bb->in_bb [in_bb_index];
- if (in_bb->out_count > 1) {
+ /*
+ * Have to remove non-critical edges whose source ends with a BR_REG
+ * ins too, since inserting a computation before the BR_REG could
+ * overwrite the sreg1 of the ins.
+ */
+ if ((in_bb->out_count > 1) || (in_bb->out_count == 1 && in_bb->last_ins && in_bb->last_ins->opcode == OP_BR_REG)) {
MonoBasicBlock *new_bb = mono_mempool_alloc0 ((cfg)->mempool, sizeof (MonoBasicBlock));
new_bb->block_num = cfg->num_bblocks++;
// new_bb->real_offset = bb->real_offset;
new_bb->region = bb->region;
/* Do not alter the CFG while altering the BB list */
- if (previous_bb->region == bb->region) {
+ if (mono_bb_is_fall_through (cfg, previous_bb)) {
if (previous_bb != cfg->bb_entry) {
- /* If previous_bb "followed through" to bb, */
- /* keep it linked with a OP_BR */
- if ((previous_bb->last_ins == NULL) ||
- !MONO_IS_BRANCH_OP (previous_bb->last_ins)) {
- int i;
- /* Make sure previous_bb really falls through bb */
- for (i = 0; i < previous_bb->out_count; i++) {
- if (previous_bb->out_bb [i] == bb) {
- MonoInst *jump;
- MONO_INST_NEW (cfg, jump, OP_BR);
- MONO_ADD_INS (previous_bb, jump);
- jump->cil_code = previous_bb->cil_code;
- jump->inst_target_bb = bb;
- break;
- }
+ int i;
+ /* Make sure previous_bb really falls through bb */
+ for (i = 0; i < previous_bb->out_count; i++) {
+ if (previous_bb->out_bb [i] == bb) {
+ MonoInst *jump;
+ MONO_INST_NEW (cfg, jump, OP_BR);
+ MONO_ADD_INS (previous_bb, jump);
+ jump->cil_code = previous_bb->cil_code;
+ jump->inst_target_bb = bb;
+ break;
}
}
} else {
MONO_ADD_INS (new_bb_after_entry, jump);
jump->cil_code = bb->cil_code;
jump->inst_target_bb = bb;
+
+ mono_unlink_bblock (cfg, previous_bb, bb);
+ mono_link_bblock (cfg, new_bb_after_entry, bb);
+ mono_link_bblock (cfg, previous_bb, new_bb_after_entry);
previous_bb->next_bb = new_bb_after_entry;
previous_bb = new_bb_after_entry;
-
+
if (cfg->verbose_level > 2) {
printf ("remove_critical_edges, added helper BB%d jumping to BB%d\n", new_bb_after_entry->block_num, bb->block_num);
}
printf (")");
if (bb->last_ins != NULL) {
printf (" ");
- mono_print_tree (bb->last_ins);
+ mono_print_ins (bb->last_ins);
}
printf ("\n");
}
}
}
-/* checks that a and b represent the same instructions, conservatively,
- * it can return FALSE also for two trees that are equal.
- * FIXME: also make sure there are no side effects.
- */
-static int
-same_trees (MonoInst *a, MonoInst *b)
-{
- int arity;
- if (a->opcode != b->opcode)
- return FALSE;
- arity = mono_burg_arity [a->opcode];
- if (arity == 1) {
- if (a->ssa_op == b->ssa_op && a->ssa_op == MONO_SSA_LOAD && a->inst_i0 == b->inst_i0)
- return TRUE;
- return same_trees (a->inst_left, b->inst_left);
- } else if (arity == 2) {
- return same_trees (a->inst_left, b->inst_left) && same_trees (a->inst_right, b->inst_right);
- } else if (arity == 0) {
- switch (a->opcode) {
- case OP_ICONST:
- return a->inst_c0 == b->inst_c0;
- default:
- return FALSE;
- }
- }
- return FALSE;
-}
-
-static int
-get_unsigned_condbranch (int opcode)
-{
- switch (opcode) {
- case CEE_BLE: return CEE_BLE_UN;
- case CEE_BLT: return CEE_BLT_UN;
- case CEE_BGE: return CEE_BGE_UN;
- case CEE_BGT: return CEE_BGT_UN;
- }
- g_assert_not_reached ();
- return 0;
-}
-
-static int
-tree_is_unsigned (MonoInst* ins) {
- switch (ins->opcode) {
- case OP_ICONST:
- return (int)ins->inst_c0 >= 0;
- /* array lengths are positive as are string sizes */
- case CEE_LDLEN:
- case OP_STRLEN:
- return TRUE;
- case CEE_CONV_U1:
- case CEE_CONV_U2:
- case CEE_CONV_U4:
- case CEE_CONV_OVF_U1:
- case CEE_CONV_OVF_U2:
- case CEE_CONV_OVF_U4:
- return TRUE;
- case CEE_LDIND_U1:
- case CEE_LDIND_U2:
- case CEE_LDIND_U4:
- return TRUE;
- default:
- return FALSE;
- }
-}
-
-/* check if an unsigned compare can be used instead of two signed compares
- * for (val < 0 || val > limit) conditionals.
- * Returns TRUE if the optimization has been applied.
- * Note that this can't be applied if the second arg is not positive...
- */
-static int
-try_unsigned_compare (MonoCompile *cfg, MonoBasicBlock *bb)
-{
- MonoBasicBlock *truet, *falset;
- MonoInst *cmp_inst = bb->last_ins->inst_left;
- MonoInst *condb;
- if (!cmp_inst->inst_right->inst_c0 == 0)
- return FALSE;
- truet = bb->last_ins->inst_true_bb;
- falset = bb->last_ins->inst_false_bb;
- if (falset->in_count != 1)
- return FALSE;
- condb = falset->last_ins;
- /* target bb must have one instruction */
- if (!condb || (condb != falset->code))
- return FALSE;
- if ((((condb->opcode == CEE_BLE || condb->opcode == CEE_BLT) && (condb->inst_false_bb == truet))
- || ((condb->opcode == CEE_BGE || condb->opcode == CEE_BGT) && (condb->inst_true_bb == truet)))
- && same_trees (cmp_inst->inst_left, condb->inst_left->inst_left)) {
- if (!tree_is_unsigned (condb->inst_left->inst_right))
- return FALSE;
- condb->opcode = get_unsigned_condbranch (condb->opcode);
- /* change the original condbranch to just point to the new unsigned check */
- bb->last_ins->opcode = OP_BR;
- bb->last_ins->inst_target_bb = falset;
- replace_out_block (bb, truet, NULL);
- replace_in_block (truet, bb, NULL);
- return TRUE;
- }
- return FALSE;
-}
-
/*
* Optimizes the branches on the Control Flow Graph
*
/* conditional branches where true and false targets are the same can be also replaced with OP_BR */
if (bb->last_ins && (bb->last_ins->opcode != OP_BR) && MONO_IS_COND_BRANCH_OP (bb->last_ins)) {
- if (!cfg->new_ir) {
- MonoInst *pop;
- MONO_INST_NEW (cfg, pop, CEE_POP);
- pop->inst_left = bb->last_ins->inst_left->inst_left;
- mono_add_ins_to_end (bb, pop);
- MONO_INST_NEW (cfg, pop, CEE_POP);
- pop->inst_left = bb->last_ins->inst_left->inst_right;
- mono_add_ins_to_end (bb, pop);
- }
bb->last_ins->opcode = OP_BR;
bb->last_ins->inst_target_bb = bb->last_ins->inst_true_bb;
changed = TRUE;
/* the block are in sequence anyway ... */
/* branches to the following block can be removed */
- if (bb->last_ins && bb->last_ins->opcode == OP_BR) {
- bb->last_ins->opcode = OP_NOP;
+ if (bb->last_ins && bb->last_ins->opcode == OP_BR && !bbn->out_of_line) {
+ NULLIFY_INS (bb->last_ins);
changed = TRUE;
if (cfg->verbose_level > 2)
g_print ("br removal triggered %d -> %d\n", bb->block_num, bbn->block_num);
int branch_result;
MonoBasicBlock *taken_branch_target = NULL, *untaken_branch_target = NULL;
- if (cfg->new_ir) {
- if (bb->last_ins->flags & MONO_INST_CFOLD_TAKEN)
- branch_result = BRANCH_TAKEN;
- else if (bb->last_ins->flags & MONO_INST_CFOLD_NOT_TAKEN)
- branch_result = BRANCH_NOT_TAKEN;
- else
- branch_result = BRANCH_UNDEF;
- }
+ if (bb->last_ins->flags & MONO_INST_CFOLD_TAKEN)
+ branch_result = BRANCH_TAKEN;
+ else if (bb->last_ins->flags & MONO_INST_CFOLD_NOT_TAKEN)
+ branch_result = BRANCH_NOT_TAKEN;
else
- branch_result = mono_eval_cond_branch (bb->last_ins);
+ branch_result = BRANCH_UNDEF;
if (branch_result == BRANCH_TAKEN) {
taken_branch_target = bb->last_ins->inst_true_bb;
* would require addition of an extra branch at the end of bbn
* slowing down loops.
*/
- if (cfg->new_ir && bbn && bb->region == bbn->region && bbn->in_count == 1 && cfg->enable_extended_bblocks && bbn != cfg->bb_exit && !bb->extended && !bbn->out_of_line && !mono_bblocks_linked (bbn, bb)) {
+ if (bbn && bb->region == bbn->region && bbn->in_count == 1 && cfg->enable_extended_bblocks && bbn != cfg->bb_exit && !bb->extended && !bbn->out_of_line && !mono_bblocks_linked (bbn, bb)) {
g_assert (bbn->in_bb [0] == bb);
if (cfg->verbose_level > 2)
g_print ("merge false branch target triggered BB%d -> BB%d\n", bb->block_num, bbn->block_num);
}
}
- /* detect and optimize to unsigned compares checks like: if (v < 0 || v > limit */
- if (bb->last_ins && bb->last_ins->opcode == CEE_BLT && !cfg->new_ir && bb->last_ins->inst_left->inst_right->opcode == OP_ICONST) {
- if (try_unsigned_compare (cfg, bb)) {
- /*g_print ("applied in bb %d (->%d) %s\n", bb->block_num, bb->last_ins->inst_target_bb->block_num, mono_method_full_name (cfg->method, TRUE));*/
- changed = TRUE;
- continue;
- }
- }
-
if (bb->last_ins && MONO_IS_COND_BRANCH_NOFP (bb->last_ins)) {
- if (bb->last_ins->inst_false_bb && bb->last_ins->inst_false_bb->out_of_line && (bb->region == bb->last_ins->inst_false_bb->region)) {
+ if (bb->last_ins->inst_false_bb && bb->last_ins->inst_false_bb->out_of_line && (bb->region == bb->last_ins->inst_false_bb->region) && !cfg->disable_out_of_line_bblocks) {
/* Reverse the branch */
bb->last_ins->opcode = mono_reverse_branch_op (bb->last_ins->opcode);
bbn = bb->last_ins->inst_false_bb;
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