Implement a simple register allocator that tries to keep instruction results in registers.

runtime/vm/flow_graph_compiler_x64.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "lib/error.h"
@@ skipping 616 matching lines @@
   __ Bind(&done);
   __ popq(RDX);  // Remove pushed instantiator type arguments.
   __ popq(RCX);  // Remove pushed instantiator.
 }
 
 
 void FlowGraphCompiler::EmitInstructionPrologue(Instruction* instr) {
   LocationSummary* locs = instr->locs();
   ASSERT(locs != NULL);
 
-  locs->AllocateRegisters();
+  frame_register_allocator()->AllocateRegisters(instr);
 
-  // Load instruction inputs into allocated registers.
-  for (intptr_t i = locs->input_count() - 1; i >= 0; i--) {
-    Location loc = locs->in(i);
-    ASSERT(loc.kind() == Location::kRegister);
-    __ popq(loc.reg());
-  }
+  // TODO(vegorov): adjust assertion when we start removing comparison from the
+  // graph when it is merged with a branch.
+  ASSERT(locs->is_call() ||
+         (instr->IsBranch() && instr->AsBranch()->is_fused_with_comparison()) ||
+         (locs->input_count() == instr->InputCount()));
 }
 
 
 // Copied from CodeGenerator::CopyParameters (CodeGenerator will be deprecated).
 void FlowGraphCompiler::CopyParameters() {
   const Function& function = parsed_function().function();
   LocalScope* scope = parsed_function().node_sequence()->scope();
   const int num_fixed_params = function.num_fixed_parameters();
   const int num_opt_params = function.num_optional_parameters();
   ASSERT(parsed_function().first_parameter_index() ==
@@ skipping 327 matching lines @@
                                        -1);
   __ jmp(&StubCode::FixCallersTargetLabel());
 }
 
 
 // Infrastructure copied from class CodeGenerator.
 void FlowGraphCompiler::GenerateCall(intptr_t token_index,
                                      intptr_t try_index,
                                      const ExternalLabel* label,
                                      PcDescriptors::Kind kind) {
+  ASSERT(frame_register_allocator()->IsSpilled());
   __ call(label);
   AddCurrentDescriptor(kind, AstNode::kNoId, token_index, try_index);
 }
 
 
 void FlowGraphCompiler::GenerateCallRuntime(intptr_t cid,
                                             intptr_t token_index,
                                             intptr_t try_index,
                                             const RuntimeEntry& entry) {
+  ASSERT(frame_register_allocator()->IsSpilled());
   __ CallRuntime(entry);
   AddCurrentDescriptor(PcDescriptors::kOther, cid, token_index, try_index);
 }
 
 
 // Checks class id of instance against all 'class_ids'. Jump to 'deopt' label
 // if no match or instance is Smi.
 void FlowGraphCompiler::EmitClassChecksNoSmi(
     const ZoneGrowableArray<intptr_t>& class_ids,
     Register instance_reg,
@@ skipping 39 matching lines @@
   __ cvtsi2sd(result, temp);
   __ Bind(&done);
 }
 
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64