Add RWPI/ROPI relocation model support

Adds support for using LLVM 4's ROPI and RWPI relocation models for ARM

src/librustc_llvm/ffi.rs

@@ -288,6 +288,9 @@ pub enum RelocMode {
     Static = 1,
     PIC = 2,
     DynamicNoPic = 3,
+    ROPI = 4,
+    RWPI = 5,
+    ROPI_RWPI = 6,
 }
 
 /// LLVMRustCodeModel

src/librustc_trans/back/write.rs

@@ -37,11 +37,14 @@ use std::sync::mpsc::channel;
 use std::thread;
 use libc::{c_uint, c_void};
 
-pub const RELOC_MODEL_ARGS : [(&'static str, llvm::RelocMode); 4] = [
+pub const RELOC_MODEL_ARGS : [(&'static str, llvm::RelocMode); 7] = [
     ("pic", llvm::RelocMode::PIC),
     ("static", llvm::RelocMode::Static),
     ("default", llvm::RelocMode::Default),
     ("dynamic-no-pic", llvm::RelocMode::DynamicNoPic),
+    ("ropi", llvm::RelocMode::ROPI),
+    ("rwpi", llvm::RelocMode::RWPI),
+    ("ropi-rwpi", llvm::RelocMode::ROPI_RWPI),
 ];
 
 pub const CODE_GEN_MODEL_ARGS : [(&'static str, llvm::CodeModel); 5] = [

src/rustllvm/PassWrapper.cpp

@@ -290,7 +290,7 @@ extern "C" void LLVMRustPrintTargetFeatures(LLVMTargetMachineRef) {
 
 extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
     const char *TripleStr, const char *CPU, const char *Feature,
-    LLVMRustCodeModel RustCM, LLVMRelocMode Reloc,
+    LLVMRustCodeModel RustCM, int Reloc,
     LLVMRustCodeGenOptLevel RustOptLevel, bool UseSoftFloat,
     bool PositionIndependentExecutable, bool FunctionSections,
     bool DataSections) {
@@ -304,15 +304,26 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
   auto OptLevel = fromRust(RustOptLevel);
 
   switch (Reloc) {
-  case LLVMRelocStatic:
+  case 1:
     RM = Reloc::Static;
     break;
-  case LLVMRelocPIC:
+  case 2:
     RM = Reloc::PIC_;
     break;
-  case LLVMRelocDynamicNoPic:
+  case 3:
     RM = Reloc::DynamicNoPIC;
     break;
+#if LLVM_VERSION_GE(4, 0)
+  case 4:
+    RM = Reloc::ROPI;
+    break;
+  case 5:
+    RM = Reloc::RWPI;
+    break;
+  case 6:
+    RM = Reloc::ROPI_RWPI;
+    break;
+#endif
   default:
 #if LLVM_VERSION_LE(3, 8)
     RM = Reloc::Default;