Preliminary changes to allow mips target to build.

It compiles, but it doesn't work yet.

Change-Id: I2973a03bd956d8d398b9cfd1047e66fbf3ff439c
diff --git a/src/compiler/codegen/mips/MipsLIR.h b/src/compiler/codegen/mips/MipsLIR.h
index 4850205..5852b31 100644
--- a/src/compiler/codegen/mips/MipsLIR.h
+++ b/src/compiler/codegen/mips/MipsLIR.h
@@ -148,7 +148,7 @@
 #define LOC_C_RETURN {kLocPhysReg, 0, 0, 0, 0, 0, 0, 0, 1, r_V0, INVALID_REG, \
                       INVALID_SREG, INVALID_SREG}
 #define LOC_C_RETURN_FLOAT  LOC_C_RETURN
-#define LOC_C_RETURN_ALT {kLocPhysReg, 0, 0, 0, 0, 0, 0, 0, 1, r_F0, \
+#define LOC_C_RETURN_ALT {kLocPhysReg, 0, 0, 0, 0, 0, 0, 0, 1, r_V1, \
                           INVALID_REG, INVALID_SREG, INVALID_SREG}
 #define LOC_C_RETURN_WIDE {kLocPhysReg, 1, 0, 0, 0, 0, 0, 0, 1, r_RESULT0, \
                            r_RESULT1, INVALID_SREG, INVALID_SREG}
diff --git a/src/compiler/codegen/mips/MipsRallocUtil.cc b/src/compiler/codegen/mips/MipsRallocUtil.cc
index ded59f0..43fcc07 100644
--- a/src/compiler/codegen/mips/MipsRallocUtil.cc
+++ b/src/compiler/codegen/mips/MipsRallocUtil.cc
@@ -149,8 +149,9 @@
 
 extern RegLocation oatGetReturnAlt(CompilationUnit* cUnit)
 {
-  UNIMPLEMENTED(FATAL);
-  RegLocation res = LOC_C_RETURN;
+  RegLocation res = LOC_C_RETURN_ALT;
+  oatClobber(cUnit, res.lowReg);
+  oatMarkInUse(cUnit, res.lowReg);
   return res;
 }