Working toward registration of register allocators.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29360 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/PassSupport.h

@@ -368,6 +368,76 @@ struct PassRegistrationListener {
   virtual void passEnumerate(const PassInfo *P) {}
 };
 
+
+//===---------------------------------------------------------------------===//
+///
+/// RegisterRegAlloc class - Track the registration of register allocators.
+///
+class RegisterRegAlloc {
+
+public:
+
+  typedef FunctionPass *(*FunctionPassCtor)();
+
+private:
+
+  static RegisterRegAlloc *List;        // Linked list of register allocators.
+  
+  RegisterRegAlloc *Next;               // Next allocation scheme in list.
+  const char *Name;                     // Name of register allocator.
+  const char *Description;              // Description string.
+  FunctionPassCtor Ctor;                // Function to construct register
+                                        // allocator pass.
+public:
+
+  RegisterRegAlloc(const char *N, const char *D, FunctionPassCtor C)
+  : Name(N)
+  , Description(D)
+  , Ctor(C) {
+    Add();
+  }
+  
+  ~RegisterRegAlloc() {
+    Remove();
+  }
+  
+  
+  // Accessors
+  const char *getName()        const { return Name; }
+  const char *getDescription() const { return Description; }
+  FunctionPassCtor getCtor()   const { return Ctor; }
+  
+  
+  /// Add - Adds a register allocator to the registration list.
+  ///
+  void Add() {
+    Next = List;
+    List = this;
+  }
+  
+
+  /// Remove - Removes a register allocator from the registration list.
+  ///
+  void Remove() {
+    for (RegisterRegAlloc **RA = &List; *RA; RA = &(*RA)->Next) {
+      if (*RA == this) {
+        *RA = Next;
+        break;
+      }
+    }
+  }
+  
+  
+  /// Find - Finds a register allocator in registration list.
+  ///
+  static FunctionPassCtor Find(const char *N);
+
+#ifndef NDEBUG  
+  static void print();
+#endif
+};
+
+
 } // End llvm namespace
 
 #endif

lib/CodeGen/Passes.cpp

@@ -13,6 +13,7 @@
 //===---------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/Passes.h"
+#include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
 #include <iostream>
 using namespace llvm;
@@ -33,17 +34,52 @@ namespace {
     cl::init(linearscan));
 }
 
-FunctionPass *llvm::createRegisterAllocator() {
-  switch (RegAlloc) {
-  default:
-    std::cerr << "no register allocator selected";
-    abort();
-  case simple:
-    return createSimpleRegisterAllocator();
-  case local:
-    return createLocalRegisterAllocator();
-  case linearscan:
-    return createLinearScanRegisterAllocator();
+
+RegisterRegAlloc *RegisterRegAlloc::List = NULL;
+
+/// Find - Finds a register allocator in registration list.
+///
+RegisterRegAlloc::FunctionPassCtor RegisterRegAlloc::Find(const char *N) {
+  for (RegisterRegAlloc *RA = List; RA; RA = RA->Next) {
+    if (strcmp(N, RA->Name) == 0) return RA->Ctor;
   }
+  return NULL;
 }
 
+
+#ifndef NDEBUG  
+void RegisterRegAlloc::print() {
+  for (RegisterRegAlloc *RA = List; RA; RA = RA->Next) {
+    std::cerr << "RegAlloc:" << RA->Name << "\n";
+  }
+}
+#endif
+
+
+static RegisterRegAlloc
+  simpleRegAlloc("simple", "  simple register allocator",
+                 createSimpleRegisterAllocator);
+
+static RegisterRegAlloc
+  localRegAlloc("local", "  local register allocator",
+                createLocalRegisterAllocator);
+
+static RegisterRegAlloc
+  linearscanRegAlloc("linearscan", "linear scan register allocator",
+                     createLinearScanRegisterAllocator);
+
+
+FunctionPass *llvm::createRegisterAllocator() {
+  const char *Names[] = {"simple", "local", "linearscan"};
+  const char *DefltName = "linearscan";
+  
+  RegisterRegAlloc::FunctionPassCtor Ctor =
+                    RegisterRegAlloc::Find(Names[RegAlloc]);
+  if (!Ctor) Ctor = RegisterRegAlloc::Find(DefltName);
+
+  assert(Ctor && "No register allocator found");
+  
+  return Ctor();
+}
+
+