MIPS32: Improve method invocation

Improvements include:
- CodeGeneratorMIPS::GenerateStaticOrDirectCall() supports:
  - MethodLoadKind::kDirectAddressWithFixup (via literals)
  - CodePtrLocation::kCallDirectWithFixup (via literals)
  - MethodLoadKind::kDexCachePcRelative
- 32-bit literals to support the above (not ready for general-
  purpose applications yet because RA is not saved in leaf
  methods, but is clobbered on MIPS32R2 when simulating
  PC-relative addressing (MIPS32R6 is OK because it has
  PC-relative addressing with the lwpc instruction))
- shorter instruction sequences for recursive static/direct
  calls

Tested:
- test-art-host-gtest
- test-art-target-gtest and test-art-target-run-test-optimizing on:
  - MIPS32R2 QEMU
  - CI20 board
  - MIPS32R6 (2nd arch) QEMU

Change-Id: Id5b137ad32d5590487fd154c9a01d3b3e7e044ff
diff --git a/compiler/optimizing/nodes_mips.h b/compiler/optimizing/nodes_mips.h
new file mode 100644
index 0000000..de77245
--- /dev/null
+++ b/compiler/optimizing/nodes_mips.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2016 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_COMPILER_OPTIMIZING_NODES_MIPS_H_
+#define ART_COMPILER_OPTIMIZING_NODES_MIPS_H_
+
+namespace art {
+
+// Compute the address of the method for MIPS Constant area support.
+class HMipsComputeBaseMethodAddress : public HExpression<0> {
+ public:
+  // Treat the value as an int32_t, but it is really a 32 bit native pointer.
+  HMipsComputeBaseMethodAddress()
+      : HExpression(Primitive::kPrimInt, SideEffects::None(), kNoDexPc) {}
+
+  bool CanBeMoved() const OVERRIDE { return true; }
+
+  DECLARE_INSTRUCTION(MipsComputeBaseMethodAddress);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(HMipsComputeBaseMethodAddress);
+};
+
+class HMipsDexCacheArraysBase : public HExpression<0> {
+ public:
+  explicit HMipsDexCacheArraysBase(const DexFile& dex_file)
+      : HExpression(Primitive::kPrimInt, SideEffects::None(), kNoDexPc),
+        dex_file_(&dex_file),
+        element_offset_(static_cast<size_t>(-1)) { }
+
+  bool CanBeMoved() const OVERRIDE { return true; }
+
+  void UpdateElementOffset(size_t element_offset) {
+    // We'll maximize the range of a single load instruction for dex cache array accesses
+    // by aligning offset -32768 with the offset of the first used element.
+    element_offset_ = std::min(element_offset_, element_offset);
+  }
+
+  const DexFile& GetDexFile() const {
+    return *dex_file_;
+  }
+
+  size_t GetElementOffset() const {
+    return element_offset_;
+  }
+
+  DECLARE_INSTRUCTION(MipsDexCacheArraysBase);
+
+ private:
+  const DexFile* dex_file_;
+  size_t element_offset_;
+
+  DISALLOW_COPY_AND_ASSIGN(HMipsDexCacheArraysBase);
+};
+
+}  // namespace art
+
+#endif  // ART_COMPILER_OPTIMIZING_NODES_MIPS_H_