Add a new "NewDebugLoc" class which will eventually replace DebugLoc,

and will replace the 'DbgInfo' member in Instruction.

The benefit of NewDebugLoc is that it is compact (8 bytes vs 12/24 
bytes for the DbgInfo member in Instruction on a 32/64 bit system),
it means that we will end up not having to allocate MDNodes to 
represent the "DILocations" in common cases of -O0 -g, and it is
much more efficient to get things out of than the MDNode.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100072 91177308-0d34-0410-b5e6-96231b3b80d8

lib/VMCore/LLVMContextImpl.h

@@ -90,6 +90,29 @@ struct DenseMapAPFloatKeyInfo {
   }
 };
 
+/// DebugRecVH - This is a CallbackVH used to keep the Scope -> index maps
+/// up to date as MDNodes mutate.  This class is implemented in DebugLoc.cpp.
+class DebugRecVH : public CallbackVH {
+  /// Ctx - This is the LLVM Context being referenced.
+  LLVMContextImpl *Ctx;
+  
+  /// Idx - The index into either ScopeRecordIdx or ScopeInlinedAtRecords that
+  /// this reference lives in.  If this is zero, then it represents a
+  /// non-canonical entry that has no DenseMap value.  This can happen due to
+  /// RAUW.
+  int Idx;
+public:
+  DebugRecVH(MDNode *n, LLVMContextImpl *ctx, int idx)
+    : CallbackVH(n), Ctx(ctx), Idx(idx) {}
+  
+  MDNode *get() const {
+    return cast_or_null<MDNode>(getValPtr());
+  }
+  
+  virtual void deleted();
+  virtual void allUsesReplacedWith(Value *VNew);
+};
+  
 class LLVMContextImpl {
 public:
   typedef DenseMap<DenseMapAPIntKeyInfo::KeyTy, ConstantInt*, 
@@ -128,7 +151,6 @@ public:
   VectorConstantsTy VectorConstants;
   
   ConstantUniqueMap<char, PointerType, ConstantPointerNull> NullPtrConstants;
-  
   ConstantUniqueMap<char, Type, UndefValue> UndefValueConstants;
   
   DenseMap<std::pair<Function*, BasicBlock*> , BlockAddress*> BlockAddresses;
@@ -195,6 +217,27 @@ public:
   /// context.
   DenseMap<const Instruction *, MDMapTy> MetadataStore;
   
+  /// ScopeRecordIdx - This is the index in ScopeRecords for an MDNode scope
+  /// entry with no "inlined at" element.
+  DenseMap<MDNode*, int> ScopeRecordIdx;
+  
+  /// ScopeRecords - These are the actual mdnodes (in a value handle) for an
+  /// index.  The ValueHandle ensures that ScopeRecordIdx stays up to date if
+  /// the MDNode is RAUW'd.
+  std::vector<DebugRecVH> ScopeRecords;
+  
+  /// ScopeInlinedAtIdx - This is the index in ScopeInlinedAtRecords for an
+  /// scope/inlined-at pair.
+  DenseMap<std::pair<MDNode*, MDNode*>, int> ScopeInlinedAtIdx;
+  
+  /// ScopeInlinedAtRecords - These are the actual mdnodes (in value handles)
+  /// for an index.  The ValueHandle ensures that ScopeINlinedAtIdx stays up
+  /// to date.
+  std::vector<std::pair<DebugRecVH, DebugRecVH> > ScopeInlinedAtRecords;
+  
+  int getOrAddScopeRecordIdxEntry(MDNode *N, int ExistingIdx);
+  int getOrAddScopeInlinedAtIdxEntry(MDNode *Scope, MDNode *IA,int ExistingIdx);
+  
   LLVMContextImpl(LLVMContext &C);
   ~LLVMContextImpl();
 };