Optimize functions containing try-catch.

runtime/vm/flow_graph_compiler_x64.cc

Index: runtime/vm/flow_graph_compiler_x64.cc
===================================================================
--- runtime/vm/flow_graph_compiler_x64.cc	(revision 22436)
+++ runtime/vm/flow_graph_compiler_x64.cc	(working copy)
@@ -642,10 +642,92 @@
                            Scanner::kDummyTokenIndex);
     }
     AllocateRegistersLocally(instr);
+  } else if (instr->MayThrow()  &&
+             (CurrentTryIndex() != CatchClauseNode::kInvalidTryIndex)) {
+    // Optimized try-block: Sync locals to fixed stack locations.
+    EmitTrySync(instr, CurrentTryIndex());
   }
 }
 
 
+void FlowGraphCompiler::EmitTrySync(Instruction* instr, intptr_t try_index) {
+  ASSERT(is_optimizing());
+  Environment* env = instr->env();
+  CatchBlockEntryInstr* catch_block =
+      flow_graph().graph_entry()->GetCatchEntry(try_index);
+  const GrowableArray<Definition*>* idefs = catch_block->initial_definitions();
+  // Parameters.
+  intptr_t i = 0;
+  bool push_emitted = false;
+  for (; i < flow_graph().num_non_copied_params(); ++i) {
+    if ((*idefs)[i]->IsConstant()) continue;  // common constants
+    Location loc = env->LocationAt(i);
+    const intptr_t index = flow_graph().num_non_copied_params() - i;
+    Address dest(RBP, (kLastParamSlotIndex + index - 1) * kWordSize);
+    if (loc.IsConstant()) {
+      if (!push_emitted) {
+        __ pushq(RAX);
+        push_emitted = true;
+      }
+      __ LoadObject(RAX, loc.constant());
+      __ movq(dest, RAX);
+    } else if (loc.IsRegister()) {
+      __ movq(dest, loc.reg());
+    } else {
+      Address src = loc.ToStackSlotAddress();
+      if (!src.Equals(dest)) {
+        if (!push_emitted) {
+          __ pushq(RAX);
+          push_emitted = true;
+        }
+        __ movq(RAX, src);
+        __ movq(dest, RAX);
+      }
+    }
+  }
+  // Process locals. Skip exception_var and stacktrace_var.
+  CatchEntryInstr* catch_entry = catch_block->next()->AsCatchEntry();
+  intptr_t nncp = flow_graph_.num_non_copied_params();
+  intptr_t ex_idx =
+      kFirstLocalSlotIndex - catch_entry->exception_var().index() + nncp;
+  intptr_t st_idx =
+      kFirstLocalSlotIndex - catch_entry->stacktrace_var().index() + nncp;
+  for (; i < flow_graph().variable_count(); ++i) {
+    if (i == ex_idx || i == st_idx) continue;
+    if ((*idefs)[i]->IsConstant()) continue;
+    Location loc = env->LocationAt(i);
+    const intptr_t index =  i - flow_graph().num_non_copied_params();
+    Address dest(RBP, (kFirstLocalSlotIndex - index) * kWordSize);
+    if (loc.IsConstant()) {
+      if (!push_emitted) {
+        __ pushq(RAX);
+        push_emitted = true;
+      }
+      __ LoadObject(RAX, loc.constant());
+      __ movq(dest, RAX);
+    } else if (loc.IsRegister()) {
+        __ movq(dest, loc.reg());
+    } else {
+      Address src = loc.ToStackSlotAddress();
+      if (!src.Equals(dest)) {
+        if (!push_emitted) {
+          __ pushq(RAX);
+          push_emitted = true;
+        }
+        __ movq(RAX, src);
+        __ movq(dest, RAX);
+      }
+    }
+    // Update safepoint bitmap to indicate that the target location
+    // now contains a pointer.
+    instr->locs()->stack_bitmap()->Set(index, true);
+  }
+  if (push_emitted) {
+    __ popq(RAX);
+  }
+}
+
+
 void FlowGraphCompiler::EmitInstructionEpilogue(Instruction* instr) {
   if (is_optimizing()) return;
   Definition* defn = instr->AsDefinition();
@@ -936,7 +1018,7 @@
                      0);  // No token position.
   }
   __ Comment("Enter frame");
-  __ EnterDartFrame((StackSize() * kWordSize));
+  __ EnterDartFrame(StackSize() * kWordSize);
 }