Optimize functions containing try-catch.

runtime/vm/flow_graph.cc

Index: runtime/vm/flow_graph.cc
===================================================================
--- runtime/vm/flow_graph.cc	(revision 22436)
+++ runtime/vm/flow_graph.cc	(working copy)
@@ -9,6 +9,7 @@
 #include "vm/intermediate_language.h"
 #include "vm/longjump.h"
 #include "vm/growable_array.h"
+#include "vm/il_printer.h"

[srdjan, 2013/05/07 17:34:05]

Remove.

[Florian Schneider, 2013/05/08 08:57:47]

Done.

 
 namespace dart {
 
@@ -327,8 +328,13 @@
     const intptr_t block_count = flow_graph_->preorder().length();
     for (intptr_t i = 0; i < block_count; i++) {
       BlockEntryInstr* block = flow_graph_->preorder()[i];
+      // All locals are assigned inside try-catch.
       BitVector* kill = GetKillSet(block);
-      kill->Intersect(GetLiveOutSet(block));
+      if (block->try_index() != CatchClauseNode::kInvalidTryIndex) {
+        kill->SetAll();
+      } else {
+        kill->Intersect(GetLiveOutSet(block));
+      }
       assigned_vars_.Add(kill);
     }
 
@@ -373,10 +379,17 @@
   for (intptr_t i = 0; i < block_count; i++) {
     BlockEntryInstr* block = postorder_[i];
 
+

[srdjan, 2013/05/07 17:34:05]

Two lines space seems too match within a function (also some places below).

[Florian Schneider, 2013/05/08 08:57:47]

Done.

     BitVector* kill = kill_[i];
     BitVector* live_in = live_in_[i];
     last_loads->Clear();
 
+    // Inside try-catch all locals are live.
+    if (block->try_index() != CatchClauseNode::kInvalidTryIndex) {
+      live_in->SetAll();
+      continue;
+    }
+
     // Iterate backwards starting at the last instruction.
     for (BackwardInstructionIterator it(block); !it.Done(); it.Advance()) {
       Instruction* current = it.Current();
@@ -385,7 +398,7 @@
       if (load != NULL) {
         const intptr_t index = load->local().BitIndexIn(num_non_copied_params_);
         live_in->Add(index);
-        if (!last_loads->Contains(index)) {
+        if (!last_loads->Contains(index) && !load->local().always_live()) {
           last_loads->Add(index);
           load->mark_last();
         }
@@ -393,7 +406,7 @@
       }
 
       StoreLocalInstr* store = current->AsStoreLocal();
-      if (store != NULL) {
+      if (store != NULL && !store->local().always_live()) {
         const intptr_t index =
             store->local().BitIndexIn(num_non_copied_params_);
         if (kill->Contains(index)) {
@@ -406,7 +419,9 @@
           }
           kill->Add(index);
         }
-        live_in->Remove(index);
+        if (block->try_index() == CatchClauseNode::kInvalidTryIndex) {
+          live_in->Remove(index);
+        }
         continue;
       }
     }
@@ -616,11 +631,6 @@
 void FlowGraph::Rename(GrowableArray<PhiInstr*>* live_phis,
                        VariableLivenessAnalysis* variable_liveness,
                        ZoneGrowableArray<Definition*>* inlining_parameters) {
-  // TODO(fschneider): Support catch-entry.
-  if (graph_entry_->SuccessorCount() > 1) {
-    Bailout("Catch-entry support in SSA.");
-  }
-
   // Initial renaming environment.
   GrowableArray<Definition*> env(variable_count());
 
@@ -653,9 +663,14 @@
     env.Add(constant_null());
   }
 
-  BlockEntryInstr* normal_entry = graph_entry_->SuccessorAt(0);
-  ASSERT(normal_entry != NULL);  // Must have entry.
-  RenameRecursive(normal_entry, &env, live_phis, variable_liveness);
+  if (graph_entry_->SuccessorCount() > 1) {
+    // Functions with try-catch have a fixed area of stack slots reserved
+    // so that all local variables are stored at a known location when
+    // on entry to the catch.
+    graph_entry_->set_fixed_slot_count(
+        num_stack_locals() + num_copied_params());
+  }
+  RenameRecursive(graph_entry_, &env, live_phis, variable_liveness);
 }
 
 
@@ -689,9 +704,22 @@
         if (phi != NULL) {
           (*env)[i] = phi;
           phi->set_ssa_temp_index(alloc_ssa_temp_index());  // New SSA temp.
+          if (block_entry->try_index() != CatchClauseNode::kInvalidTryIndex) {
+            phi->mark_alive();
+            live_phis->Add(phi);
+          }
         }
       }
     }
+  } else if (block_entry->IsCatchBlockEntry()) {
+    // Add real definitions for all locals and parameters. The location of the
+    // parameters and locals is the same as at function entry.
+    for (intptr_t i = 0; i < env->length(); ++i) {
+      ParameterInstr* param = new ParameterInstr(i, block_entry);
+      param->set_ssa_temp_index(alloc_ssa_temp_index());  // New SSA temp.
+      (*env)[i] = param;
+      block_entry->AsCatchBlockEntry()->initial_definitions()->Add(param);
+    }
   }
 
   // Attach environment to the block entry.
@@ -750,7 +778,8 @@
           index = store->local().BitIndexIn(num_non_copied_params_);
           result = store->value()->definition();
 
-          if (variable_liveness->IsStoreAlive(block_entry, store)) {
+          if (variable_liveness->IsStoreAlive(block_entry, store) ||
+              store->local().always_live()) {
             (*env)[index] = result;
           } else {
             (*env)[index] = constant_null();
@@ -768,7 +797,8 @@
             live_phis->Add(phi);
           }
 
-          if (variable_liveness->IsLastLoad(block_entry, load)) {
+          if (variable_liveness->IsLastLoad(block_entry, load) &&
+              !load->local().always_live()) {
             (*env)[index] = constant_null();
           }
         }
@@ -796,6 +826,7 @@
     }
   }
 
+
   // 3. Process dominated blocks.
   for (intptr_t i = 0; i < block_entry->dominated_blocks().length(); ++i) {
     BlockEntryInstr* block = block_entry->dominated_blocks()[i];