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/relative_patcher.cc b/compiler/linker/relative_patcher.cc
index 3a22983..7765594 100644
--- a/compiler/linker/relative_patcher.cc
+++ b/compiler/linker/relative_patcher.cc
@@ -22,6 +22,9 @@
 #ifdef ART_ENABLE_CODEGEN_arm64
 #include "linker/arm64/relative_patcher_arm64.h"
 #endif
+#ifdef ART_ENABLE_CODEGEN_mips
+#include "linker/mips/relative_patcher_mips.h"
+#endif
 #ifdef ART_ENABLE_CODEGEN_x86
 #include "linker/x86/relative_patcher_x86.h"
 #endif
@@ -95,6 +98,11 @@
       return std::unique_ptr<RelativePatcher>(
           new Arm64RelativePatcher(provider, features->AsArm64InstructionSetFeatures()));
 #endif
+#ifdef ART_ENABLE_CODEGEN_mips
+    case kMips:
+      return std::unique_ptr<RelativePatcher>(
+          new MipsRelativePatcher(features->AsMipsInstructionSetFeatures()));
+#endif
     default:
       return std::unique_ptr<RelativePatcher>(new RelativePatcherNone);
   }