[MIPS GlobalISel] Adding GlobalISel

Add GlobalISel infrastructure up to the point where we can select a ret
void.

Patch by Petar Avramovic.

Differential Revision: https://reviews.llvm.org/D43583

llvm-svn: 325888
diff --git a/llvm/lib/Target/Mips/Mips.h b/llvm/lib/Target/Mips/Mips.h
index 008b950..f722388 100644
--- a/llvm/lib/Target/Mips/Mips.h
+++ b/llvm/lib/Target/Mips/Mips.h
@@ -22,6 +22,10 @@
   class MipsTargetMachine;
   class ModulePass;
   class FunctionPass;
+  class MipsRegisterBankInfo;
+  class MipsSubtarget;
+  class MipsTargetMachine;
+  class InstructionSelector;
 
   ModulePass *createMipsOs16Pass();
   ModulePass *createMips16HardFloatPass();
@@ -33,6 +37,10 @@
   FunctionPass *createMipsLongBranchPass();
   FunctionPass *createMipsConstantIslandPass();
   FunctionPass *createMicroMipsSizeReductionPass();
+
+  InstructionSelector *createMipsInstructionSelector(const MipsTargetMachine &,
+                                                     MipsSubtarget &,
+                                                     MipsRegisterBankInfo &);
 } // end namespace llvm;
 
 #endif