Skeleton of a linear scan register allocator.

runtime/vm/flow_graph_compiler_x64.cc

Index: runtime/vm/flow_graph_compiler_x64.cc
diff --git a/runtime/vm/flow_graph_compiler_x64.cc b/runtime/vm/flow_graph_compiler_x64.cc
index bfc547d799e1f43bf1596939da941407ebf53a44..baa818ca620b2d4427c263aed2777949e09758b6 100644
--- a/runtime/vm/flow_graph_compiler_x64.cc
+++ b/runtime/vm/flow_graph_compiler_x64.cc
@@ -28,11 +28,34 @@ void DeoptimizationStub::GenerateCode(FlowGraphCompiler* compiler) {
 #define __ assem->
   __ Comment("Deopt stub for id %d", deopt_id_);
   __ Bind(entry_label());
-  for (intptr_t i = 0; i < registers_.length(); i++) {
-    if (registers_[i] != kNoRegister) {
-      __ pushq(registers_[i]);
+
+  if (deoptimization_env_ == NULL) {
+    for (intptr_t i = 0; i < registers_.length(); i++) {
+      if (registers_[i] != kNoRegister) {
+        __ pushq(registers_[i]);
+      }
+    }
+  } else {
+    // We have a deoptimization environment, we have to tear down optimized
+    // frame and recreate non-optimized one.
+    __ leaq(RSP,
+            Address(RBP, ParsedFunction::kFirstLocalSlotIndex * kWordSize));
+
+    const ZoneGrowableArray<Value*>& values = deoptimization_env_->values();
+    const GrowableArray<Location>* locations = deoptimization_env_->locations();
+
+    for (intptr_t i = 0; i < values.length(); i++) {
+      Location loc = (*locations)[i];
+      if (loc.IsInvalid()) {
+        ASSERT(values[i]->IsConstant());
+        __ PushObject(values[i]->AsConstant()->value());
+      } else {
+        ASSERT(loc.IsRegister());
+        __ pushq(loc.reg());
+      }
     }
   }
+
   if (compiler->IsLeaf()) {
     Label L;
     __ call(&L);
@@ -1081,6 +1104,50 @@ void FlowGraphCompiler::LoadDoubleOrSmiToXmm(XmmRegister result,
 
 
 #undef __
+#define __ compiler_->assembler()->
+
+
+void ParallelMoveResolver::EmitMove(int index) {
+  Location source = moves_[index].src();
+  Location destination = moves_[index].dest();
+
+  ASSERT(destination.IsRegister());
+  if (source.IsRegister()) {
+    __ movq(destination.reg(), source.reg());
+  } else {
+    ASSERT(source.IsConstant());
+    __ LoadObject(destination.reg(), source.constant());
+  }
+  moves_[index].Eliminate();
+}
+
+
+void ParallelMoveResolver::EmitSwap(int index) {
+  Location source = moves_[index].src();
+  Location destination = moves_[index].dest();
+
+  ASSERT(source.IsRegister() && destination.IsRegister());
+  __ xchgq(destination.reg(), source.reg());
+
+  // The swap of source and destination has executed a move from source to
+  // destination.
+  moves_[index].Eliminate();
+
+  // Any unperformed (including pending) move with a source of either
+  // this move's source or destination needs to have their source
+  // changed to reflect the state of affairs after the swap.
+  for (int i = 0; i < moves_.length(); ++i) {
+    MoveOperands other_move = moves_[i];
+    if (other_move.Blocks(source)) {
+      moves_[i].set_src(destination);
+    } else if (other_move.Blocks(destination)) {
+      moves_[i].set_src(source);
+    }
+  }
+}
+
+
+#undef __
 
 }  // namespace dart