Begin counting references to registers, both in the frame and out....

src/register-allocator-ia32.cc

+// Copyright 2008 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "v8.h"
+
+#include "codegen.h"
+#include "register-allocator.h"
+
+namespace v8 { namespace internal {
+
+void RegisterAllocator::Initialize() {
+  registers_.Reset();
+  registers_.Use(esp);
+  registers_.Use(ebp);
+  registers_.Use(esi);
+  registers_.Use(edi);
+}
+
+
+Register RegisterAllocator::Allocate() {
+  // Return the first free register, if any.
+  for (int i = 0; i < num_registers(); i++) {
+    if (!registers_.is_used(i)) {
+      Register result = { i };
+      registers_.Use(result);
+      return result;
+    }
+  }
+
+  // Ask the current frame to spill a register.
+  ASSERT(code_generator_->frame() != NULL);
+  Register result = code_generator_->frame()->SpillAnyRegister();
+  if (!result.is(no_reg)) {
+    ASSERT(!registers_.is_used(result.code()));
+    registers_.Use(result);
+  }
+
+  return result;
+}
+
+
+} }  // namespace v8::internal