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/linker/mips/relative_patcher_mips.h b/compiler/linker/mips/relative_patcher_mips.h
new file mode 100644
index 0000000..4ff2f2f
--- /dev/null
+++ b/compiler/linker/mips/relative_patcher_mips.h
@@ -0,0 +1,57 @@
+/*
+ * 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_LINKER_MIPS_RELATIVE_PATCHER_MIPS_H_
+#define ART_COMPILER_LINKER_MIPS_RELATIVE_PATCHER_MIPS_H_
+
+#include "linker/relative_patcher.h"
+#include "arch/mips/instruction_set_features_mips.h"
+
+namespace art {
+namespace linker {
+
+class MipsRelativePatcher FINAL : public RelativePatcher {
+ public:
+  explicit MipsRelativePatcher(const MipsInstructionSetFeatures* features)
+      : is_r6(features->IsR6()) {}
+
+  uint32_t ReserveSpace(uint32_t offset,
+                        const CompiledMethod* compiled_method,
+                        MethodReference method_ref) OVERRIDE;
+  uint32_t ReserveSpaceEnd(uint32_t offset) OVERRIDE;
+  uint32_t WriteThunks(OutputStream* out, uint32_t offset) OVERRIDE;
+  void PatchCall(std::vector<uint8_t>* code,
+                 uint32_t literal_offset,
+                 uint32_t patch_offset,
+                 uint32_t target_offset) OVERRIDE;
+  void PatchPcRelativeReference(std::vector<uint8_t>* code,
+                                const LinkerPatch& patch,
+                                uint32_t patch_offset,
+                                uint32_t target_offset) OVERRIDE;
+
+ private:
+  // 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.
+  static constexpr uint32_t kDexCacheArrayLwOffset = 0x8000;
+  bool is_r6;
+
+  DISALLOW_COPY_AND_ASSIGN(MipsRelativePatcher);
+};
+
+}  // namespace linker
+}  // namespace art
+
+#endif  // ART_COMPILER_LINKER_MIPS_RELATIVE_PATCHER_MIPS_H_