[jit] Fix the loop recognition pass to handle single BB loops and enable logging...

diff --git a/mono/mini/dominators.c b/mono/mini/dominators.c
index d4071234f12e0475f79ae9979d0572dcfc19973d..b9437db9be4aea35c456101921a911d5c6529e29 100644 (file)
--- a/mono/mini/dominators.c
+++ b/mono/mini/dominators.c
@@ -17,8 +17,6 @@
 
 #ifndef DISABLE_JIT
 
-//#define DEBUG_DOMINATORS
-
 /*
  * bb->dfn == 0 means either the bblock is ignored by the dfn calculation, or
  * it is the entry bblock.
@@ -48,16 +46,17 @@ compute_dominators (MonoCompile *cfg)
        doms = g_new0 (MonoBasicBlock*, cfg->num_bblocks);
        doms [entry->dfn] = entry;
 
-#ifdef DEBUG_DOMINATORS
-       for (i = 0; i < cfg->num_bblocks; ++i) {
-               MonoBasicBlock *bb = cfg->bblocks [i];
+       if (cfg->verbose_level > 1) {
+               for (i = 0; i < cfg->num_bblocks; ++i) {
+                       int j;
+                       MonoBasicBlock *bb = cfg->bblocks [i];
 
-               printf ("BB%d IN: ", bb->block_num);
-               for (j = 0; j < bb->in_count; ++j) 
-                       printf ("%d ", bb->in_bb [j]->block_num);
-               printf ("\n");
+                       printf ("BB%d IN: ", bb->block_num);
+                       for (j = 0; j < bb->in_count; ++j)
+                               printf ("%d ", bb->in_bb [j]->block_num);
+                       printf ("\n");
+               }
        }
-#endif
 
        changed = TRUE;
        while (changed) {
@@ -142,15 +141,15 @@ compute_dominators (MonoCompile *cfg)
 
        cfg->comp_done |= MONO_COMP_DOM | MONO_COMP_IDOM;
 
-#ifdef DEBUG_DOMINATORS
-       printf ("DTREE %s %d\n", mono_method_full_name (cfg->method, TRUE), 
-               cfg->header->num_clauses);
-       for (i = 0; i < cfg->num_bblocks; ++i) {
-               MonoBasicBlock *bb = cfg->bblocks [i];
-               printf ("BB%d(dfn=%d) (IDOM=BB%d): ", bb->block_num, bb->dfn, bb->idom ? bb->idom->block_num : -1);
-               mono_blockset_print (cfg, bb->dominators, NULL, -1);
+       if (cfg->verbose_level > 1) {
+               printf ("DTREE %s %d\n", mono_method_full_name (cfg->method, TRUE),
+                       cfg->header->num_clauses);
+               for (i = 0; i < cfg->num_bblocks; ++i) {
+                       MonoBasicBlock *bb = cfg->bblocks [i];
+                       printf ("BB%d(dfn=%d) (IDOM=BB%d): ", bb->block_num, bb->dfn, bb->idom ? bb->idom->block_num : -1);
+                       mono_blockset_print (cfg, bb->dominators, NULL, -1);
+               }
        }
-#endif
 }
 
 #if 0
@@ -296,8 +295,6 @@ mono_compile_dominator_info (MonoCompile *cfg, int dom_flags)
                compute_dominance_frontier (cfg);
 }
 
-//#define DEBUG_NATURAL_LOOPS
-
 /*
  * code to detect loops and loop nesting level
  */
@@ -316,8 +313,13 @@ mono_compute_natural_loops (MonoCompile *cfg)
 
                for (j = 0; j < n->out_count; j++) {
                        MonoBasicBlock *h = n->out_bb [j];
+                       /* check for single block loops */
+                       if (n == h) {
+                               h->loop_blocks = g_list_prepend_mempool (cfg->mempool, h->loop_blocks, h);
+                               h->nesting++;
+                       }
                        /* check for back-edge from n to h */
-                       if (n != h && mono_bitset_test_fast (n->dominators, h->dfn)) {
+                       else if (n != h && mono_bitset_test_fast (n->dominators, h->dfn)) {
                                GSList *todo;
 
                                /* already in loop_blocks? */
@@ -385,9 +387,6 @@ mono_compute_natural_loops (MonoCompile *cfg)
                        /* The loop body start is the first bblock in the order they will be emitted */
                        MonoBasicBlock *h = cfg->bblocks [i];
                        MonoBasicBlock *body_start = h;
-#if defined(__native_client_codegen__)
-                       MonoInst *inst;
-#endif
                        GList *l;
 
                        for (l = h->loop_blocks; l; l = l->next) {
@@ -398,31 +397,24 @@ mono_compute_natural_loops (MonoCompile *cfg)
                                }
                        }
 
-#if defined(__native_client_codegen__)
-                       /* Instrument the loop (GC back branch safe point) */
-                       MONO_INST_NEW (cfg, inst, OP_NACL_GC_SAFE_POINT);
-                       inst->dreg = mono_alloc_dreg (cfg, STACK_I4);
-                       mono_bblock_insert_before_ins (body_start, NULL, inst);
-#endif
                        body_start->loop_body_start = 1;
                }
        }
        g_free (bb_indexes);
 
-#ifdef DEBUG_NATURAL_LOOPS
-       for (i = 0; i < cfg->num_bblocks; ++i) {
-               if (cfg->bblocks [i]->loop_blocks) {
-                       MonoBasicBlock *h = (MonoBasicBlock *)cfg->bblocks [i]->loop_blocks->data;
-                       GList *l;
-                       printf ("LOOP START %d\n", h->block_num);
-                       for (l = h->loop_blocks; l; l = l->next) {
-                               MonoBasicBlock *cb = (MonoBasicBlock *)l->data;
-                               printf (" BB%d %d %p\n", cb->block_num, cb->nesting, cb->loop_blocks);
+       if (cfg->verbose_level > 1) {
+               for (i = 0; i < cfg->num_bblocks; ++i) {
+                       if (cfg->bblocks [i]->loop_blocks) {
+                               MonoBasicBlock *h = (MonoBasicBlock *)cfg->bblocks [i]->loop_blocks->data;
+                               GList *l;
+                               printf ("LOOP START %d\n", h->block_num);
+                               for (l = h->loop_blocks; l; l = l->next) {
+                                       MonoBasicBlock *cb = (MonoBasicBlock *)l->data;
+                                       printf ("\tBB%d %d %p\n", cb->block_num, cb->nesting, cb->loop_blocks);
+                               }
                        }
                }
        }
-#endif
-
 }
 
 static void