Change the type of RegAlloc to StringRef

Author: paperchalice

llvm/include/llvm/CodeGen/CodeGenPassBuilder.h

@@ -1113,30 +1113,13 @@ void CodeGenPassBuilder<Derived>::addTargetRegisterAllocator(
 template <typename Derived>
 void CodeGenPassBuilder<Derived>::addRegAllocPass(AddMachinePass &addPass,
                                                   bool Optimized) const {
-  if (Opt.RegAlloc == RegAllocType::Default)
-    // With no -regalloc= override, ask the target for a regalloc pass.
-    derived().addTargetRegisterAllocator(addPass, Optimized);
-  else if (Opt.RegAlloc == RegAllocType::Basic)
-    addPass(RABasicPass());
-  else if (Opt.RegAlloc == RegAllocType::Fast)
-    addPass(RAFastPass());
-  else if (Opt.RegAlloc == RegAllocType::Greedy)
-    addPass(RAGreedyPass());
-  else if (Opt.RegAlloc == RegAllocType::PBQP)
-    addPass(RAPBQPPass());
-  else
-    llvm_unreachable("unknonwn register allocator type");
+  // TODO: Parse Opt.RegAlloc to add register allocator.
 }
 
 template <typename Derived>
 Error CodeGenPassBuilder<Derived>::addRegAssignmentFast(
     AddMachinePass &addPass) const {
-  if (Opt.RegAlloc != RegAllocType::Default &&
-      Opt.RegAlloc != RegAllocType::Fast)
-    return make_error<StringError>(
-        "Must use fast (default) register allocator for unoptimized regalloc.",
-        inconvertibleErrorCode());
-
+  // TODO: Ensure allocator is default or fast.
   addRegAllocPass(addPass, false);
   return Error::success();
 }

llvm/include/llvm/Target/CGPassBuilderOption.h

@@ -52,7 +52,7 @@ struct CGPassBuilderOption {
   bool RequiresCodeGenSCCOrder = false;
 
   RunOutliner EnableMachineOutliner = RunOutliner::TargetDefault;
-  RegAllocType RegAlloc = RegAllocType::Default;
+  StringRef RegAlloc = "default";
   std::optional<GlobalISelAbortMode> EnableGlobalISelAbort;
   std::string FSProfileFile;
   std::string FSRemappingFile;

llvm/tools/llc/NewPMDriver.cpp

@@ -51,16 +51,10 @@ extern cl::opt<bool> PrintPipelinePasses;
 
 using namespace llvm;
 
-static cl::opt<RegAllocType> RegAlloc(
-    "regalloc-npm", cl::desc("Register allocator to use for new pass manager"),
-    cl::Hidden, cl::ValueOptional, cl::init(RegAllocType::Default),
-    cl::values(
-        clEnumValN(RegAllocType::Default, "default",
-                   "pick register allocator based on -O option"),
-        clEnumValN(RegAllocType::Basic, "basic", "basic register allocator"),
-        clEnumValN(RegAllocType::Fast, "fast", "fast register allocator"),
-        clEnumValN(RegAllocType::Greedy, "greedy", "greedy register allocator"),
-        clEnumValN(RegAllocType::PBQP, "pbqp", "PBQP register allocator")));
+static cl::opt<std::string>
+    RegAlloc("regalloc-npm",
+             cl::desc("Register allocator to use for new pass manager"),
+             cl::Hidden, cl::init("default"));
 
 static cl::opt<bool>
     DebugPM("debug-pass-manager", cl::Hidden,