First cut at TargetMachineRegistry and RegisterTarget classes

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14742 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Target/TargetMachineRegistry.h

@@ -0,0 +1,76 @@
+//===-- Target/TargetMachineRegistry.h - Target Registration ----*- C++ -*-===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This file exposes two classes: the TargetMachineRegistry class, which allows
+// tools to inspect all of registered targets, and the RegisterTarget class,
+// which TargetMachine implementations should use to register themselves with
+// the system.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TARGET_TARGETMACHINEREGISTRY_H
+#define LLVM_TARGET_TARGETMACHINEREGISTRY_H
+
+namespace llvm {
+  class Module;
+  class TargetMachine;
+  class IntrinsicLowering;
+
+  struct TargetMachineRegistry {
+    /// Entry - One instance of this struct is created for each target that is
+    /// registered.
+    struct Entry {
+      const char *Name;
+      const char *ShortDesc;
+      TargetMachine *(*CtorFn)(const Module &, IntrinsicLowering*);
+      unsigned (*ModuleMatchQualityFn)(const Module &M);
+      unsigned (*JITMatchQualityFn)();
+
+      const Entry *getNext() const { return Next; }
+
+    protected:
+      Entry(const char *N, const char *SD,
+            TargetMachine *(*CF)(const Module &, IntrinsicLowering*),
+            unsigned (*MMF)(const Module &M), unsigned (*JMF)())
+      : Name(N), ShortDesc(SD), CtorFn(CF), ModuleMatchQualityFn(MMF),
+      JITMatchQualityFn(JMF), Next(List) {
+        List = this;
+      }
+    private:
+      const Entry *Next;  // Next entry in the linked list.
+    };
+
+    /// TargetMachineRegistry::getList - This static method returns the list of
+    /// target machines that are registered with the system.
+    static const Entry *getList() { return List; }
+
+  private:
+    static const Entry *List;
+  };
+
+  //===--------------------------------------------------------------------===//
+  /// RegisterTarget - This class is used to make targets automatically register
+  /// themselves with the tool they are linked.  Targets should define an
+  /// instance of this and implement the static methods described in the
+  /// TargetMachine comments..
+  template<class TargetMachineImpl>
+  struct RegisterTarget : public TargetMachineRegistry::Entry {
+    RegisterTarget(const char *Name, const char *ShortDesc) : 
+      TargetMachineRegistry::Entry(Name, ShortDesc, &Allocator,
+                                   &TargetMachineImpl::getModuleMatchQuality,
+                                   &TargetMachineImpl::getJITMatchQuality) {
+    }
+  private:
+    static TargetMachine *Allocator(const Module &M, IntrinsicLowering *IL) {
+      return new TargetMachineImpl(M, IL);
+    }
+  };
+}
+
+#endif