For PR780:

1. Fix the macros in IncludeFile.h to put everything in the llvm namespace
2. Replace the previous explicit mechanism in all the .h and .cpp files
   with the macros in IncludeFile.h
This gets us a consistent mechanism throughout LLVM for ensuring linkage.
Next step is to make sure its used in enough places.

llvm-svn: 28715

llvm/include/llvm/Analysis/AliasAnalysis.h

@@ -318,14 +318,13 @@ public:
   }
 };
 
+} // End llvm namespace
+
 // Because of the way .a files work, we must force the BasicAA implementation to
 // be pulled in if the AliasAnalysis header is included.  Otherwise we run
 // the risk of AliasAnalysis being used, but the default implementation not
 // being linked into the tool that uses it.
-//
+FORCE_DEFINING_FILE_TO_BE_LINKED(AliasAnalysis)
-extern int BasicAAStub;
+FORCE_DEFINING_FILE_TO_BE_LINKED(BasicAliasAnalysis)
-static IncludeFile HDR_INCLUDE_BASICAA_CPP(&BasicAAStub);
-
-} // End llvm namespace
 
 #endif

llvm/include/llvm/Analysis/CallGraph.h

@@ -287,13 +287,9 @@ template<> struct GraphTraits<const CallGraph*> :
   static nodes_iterator nodes_end  (const CallGraph *CG) { return CG->end(); }
 };
 
-// Make sure that any clients of this file link in CallGraph.cpp
-static IncludeFile
-CALLGRAPH_INCLUDE_FILE(&CallGraph::stub);
-
-extern int BasicCallGraphStub;
-static IncludeFile HDR_INCLUDE_CALLGRAPH_CPP(&BasicCallGraphStub);
-
 } // End llvm namespace
 
+// Make sure that any clients of this file link in CallGraph.cpp
+FORCE_DEFINING_FILE_TO_BE_LINKED(CallGraph)
+
 #endif

llvm/include/llvm/Analysis/Dominators.h

@@ -652,9 +652,9 @@ private:
 };
 
 
-// Make sure that any clients of this file link in Dominators.cpp
-static IncludeFile
-DOMINATORS_INCLUDE_FILE(&DominatorSet::stub);
 } // End llvm namespace
 
+// Make sure that any clients of this file link in Dominators.cpp
+FORCE_DEFINING_FILE_TO_BE_LINKED(DominatorSet)
+
 #endif

llvm/include/llvm/Analysis/FindUsedTypes.h

@@ -53,15 +53,11 @@ public:
   virtual void getAnalysisUsage(AnalysisUsage &AU) const {
     AU.setPreservesAll();
   }
-
-  // stub - dummy function, just ignore it
-  static int stub;
 };
 
-// Make sure that any clients of this file link in PostDominators.cpp
-static IncludeFile
-FIND_USED_TYPES_INCLUDE_FILE(&FindUsedTypes::stub);
-
 } // End llvm namespace
 
+// Make sure that any clients of this file link in PostDominators.cpp
+FORCE_DEFINING_FILE_TO_BE_LINKED(FindUsedTypes)
+
 #endif

llvm/include/llvm/Analysis/LoopInfo.h

@@ -295,7 +295,6 @@ public:
   /// BasicBlocks to loops.
   void removeBlock(BasicBlock *BB);
 
-  static int stub;  // Noop
 private:
   void Calculate(ETForest &EF);
   Loop *ConsiderForLoop(BasicBlock *BB, ETForest &EF);
@@ -304,10 +303,6 @@ private:
 };
 
 
-// Make sure that any clients of this file link in LoopInfo.cpp
-static IncludeFile
-LOOP_INFO_INCLUDE_FILE(&LoopInfo::stub);
-
 // Allow clients to walk the list of nested loops...
 template <> struct GraphTraits<const Loop*> {
   typedef const Loop NodeType;
@@ -337,4 +332,7 @@ template <> struct GraphTraits<Loop*> {
 
 } // End llvm namespace
 
+// Make sure that any clients of this file link in LoopInfo.cpp
+FORCE_DEFINING_FILE_TO_BE_LINKED(LoopInfo)
+
 #endif

llvm/include/llvm/Analysis/PostDominators.h

@@ -128,18 +128,14 @@ struct PostDominanceFrontier : public DominanceFrontierBase {
     AU.addRequired<PostDominatorTree>();
   }
 
-  // stub - dummy function, just ignore it
-  static int stub;
-
 private:
   const DomSetType &calculate(const PostDominatorTree &DT,
                               const DominatorTree::Node *Node);
 };
 
-// Make sure that any clients of this file link in PostDominators.cpp
-static IncludeFile
-POST_DOMINATOR_INCLUDE_FILE(&PostDominanceFrontier::stub);
-
 } // End llvm namespace
 
+// Make sure that any clients of this file link in PostDominators.cpp
+FORCE_DEFINING_FILE_TO_BE_LINKED(PostDominanceFrontier)
+
 #endif

llvm/include/llvm/Analysis/ValueNumbering.h

@@ -65,10 +65,9 @@ struct ValueNumbering {
   }
 };
 
-extern int BasicValueNumberingStub;
-static IncludeFile
-HDR_INCLUDE_VALUENUMBERING_CPP(&BasicValueNumberingStub);
-
 } // End llvm namespace
 
+// Force any file including this header to get the implementation as well
+FORCE_DEFINING_FILE_TO_BE_LINKED(BasicValueNumbering)
+
 #endif

llvm/include/llvm/IntrinsicInst.h

@@ -314,11 +314,10 @@ namespace llvm {
     }
   };
 
-// A hack to ensure that the IntrinsicInst.cpp file gets added as a dependency
-// of any file that 
-extern char LinkIntrinsicInstStub;
-static IncludeFile LinkIntrinsicInst(&LinkIntrinsicInstStub);
-
 }
 
+// Ensure that the IntrinsicInst.cpp file gets added as a dependency of any 
+// file that includes this header
+FORCE_DEFINING_FILE_TO_BE_LINKED(IntrinsicInst)
+
 #endif

llvm/include/llvm/Support/IncludeFile.h

@@ -27,13 +27,15 @@
 /// And, foo.cp would use:<br/>
 /// <tt>DEFINING_FILE_FOR(foo)</tt><br/>
 #define FORCE_DEFINING_FILE_TO_BE_LINKED(name) \
+  namespace llvm { \
     extern char name ## LinkVar; \
-  static IncludeFile name ## LinkObj ( &name ## LinkVar )
+    static IncludeFile name ## LinkObj ( &name ## LinkVar ); \
+  } 
 
 /// This macro is the counterpart to FORCE_DEFINING_FILE_TO_BE_LINKED. It should
 /// be used in a .cpp file to define the name referenced in a header file that
 /// will cause linkage of the .cpp file. It should only be used at extern level.
-#define DEFINING_FILE_FOR(name) char name
+#define DEFINING_FILE_FOR(name) namespace llvm { char name ## LinkVar; }
 
 namespace llvm {
 

llvm/include/llvm/System/IncludeFile.h

@@ -27,13 +27,15 @@
 /// And, foo.cp would use:<br/>
 /// <tt>DEFINING_FILE_FOR(foo)</tt><br/>
 #define FORCE_DEFINING_FILE_TO_BE_LINKED(name) \
+  namespace llvm { \
     extern char name ## LinkVar; \
-  static IncludeFile name ## LinkObj ( &name ## LinkVar )
+    static IncludeFile name ## LinkObj ( &name ## LinkVar ); \
+  } 
 
 /// This macro is the counterpart to FORCE_DEFINING_FILE_TO_BE_LINKED. It should
 /// be used in a .cpp file to define the name referenced in a header file that
 /// will cause linkage of the .cpp file. It should only be used at extern level.
-#define DEFINING_FILE_FOR(name) char name
+#define DEFINING_FILE_FOR(name) namespace llvm { char name ## LinkVar; }
 
 namespace llvm {
 

llvm/lib/Analysis/AliasAnalysis.cpp

@@ -188,8 +188,4 @@ bool AliasAnalysis::canInstructionRangeModify(const Instruction &I1,
 // be pulled in if the AliasAnalysis classes are pulled in.  Otherwise we run
 // the risk of AliasAnalysis being used, but the default implementation not
 // being linked into the tool that uses it.
-//
+DEFINING_FILE_FOR(AliasAnalysis)
-namespace llvm {
-  extern int BasicAAStub;
-}
-static IncludeFile INCLUDE_BASICAA_CPP((void*)&BasicAAStub);

llvm/lib/Analysis/BasicAliasAnalysis.cpp

@@ -26,9 +26,6 @@
 #include <algorithm>
 using namespace llvm;
 
-// Make sure that anything that uses AliasAnalysis pulls in this file...
-int llvm::BasicAAStub;
-
 namespace {
   /// NoAA - This class implements the -no-aa pass, which always returns "I
   /// don't know" for alias queries.  NoAA is unlike other alias analysis
@@ -846,3 +843,6 @@ BasicAliasAnalysis::getModRefBehavior(Function *F, CallSite CS,
 
   return UnknownModRefBehavior;
 }
+
+// Make sure that anything that uses AliasAnalysis pulls in this file...
+DEFINING_FILE_FOR(BasicAliasAnalysis)

llvm/lib/Analysis/IPA/CallGraph.cpp

@@ -19,8 +19,6 @@
 #include <iostream>
 using namespace llvm;
 
-int llvm::BasicCallGraphStub;
-
 static bool isOnlyADirectCall(Function *F, CallSite CS) {
   if (!CS.getInstruction()) return false;
   for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); I != E; ++I)
@@ -256,10 +254,6 @@ CallGraphNode *CallGraph::getOrInsertFunction(const Function *F) {
   return CGN = new CallGraphNode(const_cast<Function*>(F));
 }
 
-
-
-int CallGraph::stub; // to ensure linkage of this file.
-
 void CallGraphNode::print(std::ostream &OS) const {
   if (Function *F = getFunction())
     OS << "Call graph node for function: '" << F->getName() <<"'\n";
@@ -297,3 +291,6 @@ void CallGraphNode::removeAnyCallEdgeTo(CallGraphNode *Callee) {
       --i; --e;
     }
 }
+
+// Enuse that users of CallGraph.h also link with this file
+DEFINING_FILE_FOR(CallGraph)

llvm/lib/Analysis/IPA/FindUsedTypes.cpp

@@ -24,9 +24,6 @@ using namespace llvm;
 static RegisterAnalysis<FindUsedTypes>
 X("printusedtypes", "Find Used Types");
 
-// stub to help linkage
-int FindUsedTypes::stub; // to ensure linkage of this file
-
 // IncorporateType - Incorporate one type and all of its subtypes into the
 // collection of used types.
 //
@@ -104,3 +101,6 @@ void FindUsedTypes::print(std::ostream &o, const Module *M) const {
            E = UsedTypes.end(); I != E; ++I)
       o << "  " << **I << "\n";
 }
+
+// Ensure that this file gets linked in when FindUsedTypes.h is used.
+DEFINING_FILE_FOR(FindUsedTypes)

llvm/lib/Analysis/LoopInfo.cpp

@@ -86,8 +86,6 @@ void Loop::dump() const {
 //===----------------------------------------------------------------------===//
 // LoopInfo implementation
 //
-int LoopInfo::stub;
-
 bool LoopInfo::runOnFunction(Function &) {
   releaseMemory();
   Calculate(getAnalysis<ETForest>());    // Update
@@ -557,3 +555,6 @@ Loop *Loop::removeChildLoop(iterator I) {
 void Loop::removeBlockFromLoop(BasicBlock *BB) {
   RemoveFromVector(Blocks, BB);
 }
+
+// Ensure this file gets linked when LoopInfo.h is used.
+DEFINING_FILE_FOR(LoopInfo)

llvm/lib/Analysis/PostDominators.cpp

@@ -359,6 +359,5 @@ PostDominanceFrontier::calculate(const PostDominatorTree &DT,
   return S;
 }
 
-// stub - a dummy function to make linking work ok.
+// Ensure that this .cpp file gets linked when PostDominators.h is used.
-int PostDominanceFrontier::stub;
+DEFINING_FILE_FOR(PostDominanceFrontier)
-

llvm/lib/Analysis/ValueNumbering.cpp

@@ -239,4 +239,5 @@ void BVNImpl::handleTernaryInst(Instruction &I) {
 }
 
 
-int llvm::BasicValueNumberingStub; // to ensure linkage of this file
+// Ensure that users of ValueNumbering.h will link with this file
+DEFINING_FILE_FOR(BasicValueNumbering)

llvm/lib/VMCore/Dominators.cpp

@@ -304,8 +304,6 @@ bool DominatorSet::runOnFunction(Function &F) {
   return false;
 }
 
-int DominatorSet::stub;
-
 namespace llvm {
 static std::ostream &operator<<(std::ostream &o,
                                 const std::set<BasicBlock*> &BBs) {
@@ -933,3 +931,5 @@ void ETForestBase::print(std::ostream &o, const Module *) const {
   }
   o << "\n";
 }
+
+DEFINING_FILE_FOR(DominatorSet)

llvm/lib/VMCore/IntrinsicInst.cpp

@@ -71,7 +71,5 @@ std::string DbgStopPointInst::getDirectory() const {
 }
 
 //===----------------------------------------------------------------------===//
-/// LinkIntrinsicInstStub -- This is a hack to make sure that programs that
+/// Ensure that users of IntrinsicInst.h will link with this module.
-/// #include IntrinsicInst.h also link this file. See Support/IncludeFile.h
+DEFINING_FILE_FOR(IntrinsicInst)
-/// for further details.
-char llvm::LinkIntrinsicInstStub;