+using namespace llvm;
+
+//===---------------------------------------------------------------------===//
+///
+/// RegisterRegAlloc class - Track the registration of register allocators.
+///
+//===---------------------------------------------------------------------===//
+MachinePassRegistry RegisterRegAlloc::Registry;
+
+static FunctionPass *createDefaultRegisterAllocator() { return 0; }
+static RegisterRegAlloc
+defaultRegAlloc("default",
+ "pick register allocator based on -O option",
+ createDefaultRegisterAllocator);
+
+//===---------------------------------------------------------------------===//
+///
+/// RegAlloc command line options.
+///
+//===---------------------------------------------------------------------===//
+static cl::opt<RegisterRegAlloc::FunctionPassCtor, false,
+ RegisterPassParser<RegisterRegAlloc> >
+RegAlloc("regalloc",
+ cl::init(&createDefaultRegisterAllocator),
+ cl::desc("Register allocator to use"));
+
+
+//===---------------------------------------------------------------------===//
+///
+/// createRegisterAllocator - choose the appropriate register allocator.
+///
+//===---------------------------------------------------------------------===//
+FunctionPass *llvm::createRegisterAllocator(CodeGenOpt::Level OptLevel) {
+ RegisterRegAlloc::FunctionPassCtor Ctor = RegisterRegAlloc::getDefault();
+
+ if (!Ctor) {
+ Ctor = RegAlloc;
+ RegisterRegAlloc::setDefault(RegAlloc);
+ }
+
+ // This forces linking of the greedy register allocator, so -regalloc=greedy
+ // works in clang.
+ if (Ctor == createGreedyRegisterAllocator)
+ return createGreedyRegisterAllocator();
+
+ if (Ctor != createDefaultRegisterAllocator)
+ return Ctor();
+
+ // When the 'default' allocator is requested, pick one based on OptLevel.
+ switch (OptLevel) {
+ case CodeGenOpt::None:
+ return createFastRegisterAllocator();