Refactor TargetMachine, pushing handling of TargetData into the target-specific subclasses.  This has one caller-visible change: getTargetData() now returns a pointer instead of a reference.

This fixes PR 759.

llvm-svn: 28074
diff --git a/llvm/lib/Target/CBackend/CTargetMachine.h b/llvm/lib/Target/CBackend/CTargetMachine.h
index f947f65..271a2bf 100644
--- a/llvm/lib/Target/CBackend/CTargetMachine.h
+++ b/llvm/lib/Target/CBackend/CTargetMachine.h
@@ -19,8 +19,11 @@
 namespace llvm {
 
 struct CTargetMachine : public TargetMachine {
+  const TargetData DataLayout;       // Calculates type size & alignment
+
   CTargetMachine(const Module &M, const std::string &FS)
-    : TargetMachine("CBackend", M) {}
+    : TargetMachine("CBackend", M),
+      DataLayout("CBackend") {}
 
   // This is the only thing that actually does anything here.
   virtual bool addPassesToEmitFile(PassManager &PM, std::ostream &Out,
@@ -28,6 +31,8 @@
 
   // This class always works, but shouldn't be the default in most cases.
   static unsigned getModuleMatchQuality(const Module &M) { return 1; }
+  
+  virtual const TargetData       *getTargetData() const { return &DataLayout; }
 };
 
 } // End llvm namespace