Move assembler out of runtime into compiler/utils.

Other directory layout bits of clean up. There is still work to separate quick
and portable in some files (e.g. argument visitor, proxy..).

Change-Id: If8fecffda8ba5c4c47a035f0c622c538c6b58351
diff --git a/runtime/arch/context.h b/runtime/arch/context.h
new file mode 100644
index 0000000..91e0cd6
--- /dev/null
+++ b/runtime/arch/context.h
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_RUNTIME_ARCH_CONTEXT_H_
+#define ART_RUNTIME_ARCH_CONTEXT_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+namespace art {
+
+class StackVisitor;
+
+// Representation of a thread's context on the executing machine, used to implement long jumps in
+// the quick stack frame layout.
+class Context {
+ public:
+  // Creates a context for the running architecture
+  static Context* Create();
+
+  virtual ~Context() {}
+
+  // Re-initializes the registers for context re-use.
+  virtual void Reset() = 0;
+
+  // Read values from callee saves in the given frame. The frame also holds
+  // the method that holds the layout.
+  virtual void FillCalleeSaves(const StackVisitor& fr) = 0;
+
+  // Set the stack pointer value
+  virtual void SetSP(uintptr_t new_sp) = 0;
+
+  // Set the program counter value
+  virtual void SetPC(uintptr_t new_pc) = 0;
+
+  // Read the given GPR
+  virtual uintptr_t GetGPR(uint32_t reg) = 0;
+
+  // Set the given GPR.
+  virtual void SetGPR(uint32_t reg, uintptr_t value) = 0;
+
+  // Smash the caller save registers. If we're throwing, we don't want to return bogus values.
+  virtual void SmashCallerSaves() = 0;
+
+  // Switch execution of the executing context to this context
+  virtual void DoLongJump() = 0;
+
+ protected:
+  enum {
+    kBadGprBase = 0xebad6070,
+    kBadFprBase = 0xebad8070,
+  };
+};
+
+}  // namespace art
+
+#endif  // ART_RUNTIME_ARCH_CONTEXT_H_