[LLVM-C] Expand LLVMRelocMode

[CodaFi]

Summary

Add read[only|write] PIC relocation models to the C API and teach the TargetMachine API about it.

[whitequark]

LGTM

llvm/trunk/include/llvm-c/TargetMachine.h

typedef enum {
     LLVMCodeGenLevelDefault,
     LLVMCodeGenLevelAggressive
 } LLVMCodeGenOptLevel;
 
 typedef enum {
     LLVMRelocDefault,
     LLVMRelocStatic,
     LLVMRelocPIC,
-    LLVMRelocDynamicNoPic
+    LLVMRelocDynamicNoPic,
+    LLVMRelocROPI,
+    LLVMRelocRWPI,
+    LLVMRelocROPI_RWPI
 } LLVMRelocMode;
 
 typedef enum {
     LLVMCodeModelDefault,
     LLVMCodeModelJITDefault,
     LLVMCodeModelTiny,
     LLVMCodeModelSmall,
     LLVMCodeModelKernel,

llvm/trunk/lib/Target/TargetMachineC.cpp

case LLVMRelocStatic:
       RM = Reloc::Static;
       break;
     case LLVMRelocPIC:
       RM = Reloc::PIC_;
       break;
     case LLVMRelocDynamicNoPic:
       RM = Reloc::DynamicNoPIC;
       break;
+    case LLVMRelocROPI:
+      RM = Reloc::ROPI;
+      break;
+    case LLVMRelocRWPI:
+      RM = Reloc::RWPI;
+      break;
+    case LLVMRelocROPI_RWPI:
+      RM = Reloc::ROPI_RWPI;
+      break;
     default:
       break;
   }
 
   bool JIT;
   Optional<CodeModel::Model> CM = unwrap(CodeModel, JIT);
 
   CodeGenOpt::Level OL;