PR4063, with feeling: Chain PP callbacks by default.

 - This is somewhat cleaner and also fixes PR4063 for real, I had the
   order wrong so we were just creating an empty dependency file.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@70687 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Lex/PPCallbacks.h

@@ -71,6 +71,51 @@ public:
   }
 };
 
+/// PPChainedCallbacks - Simple wrapper class for chaining callbacks.
+class PPChainedCallbacks : public PPCallbacks {
+  PPCallbacks *First, *Second;
+
+public:  
+  PPChainedCallbacks(PPCallbacks *_First, PPCallbacks *_Second)
+    : First(_First), Second(_Second) {}
+  ~PPChainedCallbacks() {
+    delete Second;
+    delete First;
+  }
+
+  virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
+                           SrcMgr::CharacteristicKind FileType) {
+    First->FileChanged(Loc, Reason, FileType);
+    Second->FileChanged(Loc, Reason, FileType);
+  }
+  
+  virtual void Ident(SourceLocation Loc, const std::string &str) {
+    First->Ident(Loc, str);
+    Second->Ident(Loc, str);
+  }
+  
+  virtual void PragmaComment(SourceLocation Loc, const IdentifierInfo *Kind, 
+                             const std::string &Str) {
+    First->PragmaComment(Loc, Kind, Str);
+    Second->PragmaComment(Loc, Kind, Str);
+  }
+  
+  virtual void MacroExpands(const Token &Id, const MacroInfo* MI) {
+    First->MacroExpands(Id, MI);
+    Second->MacroExpands(Id, MI);
+  }
+  
+  virtual void MacroDefined(const IdentifierInfo *II, const MacroInfo *MI) {
+    First->MacroDefined(II, MI);
+    Second->MacroDefined(II, MI);
+  }
+
+  virtual void MacroUndefined(const IdentifierInfo *II, const MacroInfo *MI) {
+    First->MacroUndefined(II, MI);
+    Second->MacroUndefined(II, MI);
+  }
+};
+
 }  // end namespace clang
 
 #endif

include/clang/Lex/Preprocessor.h

@@ -241,7 +241,8 @@ public:
   /// it.
   PPCallbacks *getPPCallbacks() const { return Callbacks; }
   void setPPCallbacks(PPCallbacks *C) {
-    delete Callbacks;
+    if (Callbacks)
+      C = new PPChainedCallbacks(C, Callbacks);
     Callbacks = C;
   }
   

test/Preprocessor/depencies-and-pp.c → test/Preprocessor/dependencies-and-pp.c

 // RUN: clang -E -o %t.1 %s &&
 // RUN: clang -E -MD -MF %t.d -MT foo -o %t.2 %s &&
 // RUN: diff %t.1 %t.2 &&
-// RUN: grep "foo:" %t.d
+// RUN: grep "foo:" %t.d &&
+// RUN: grep "dependencies-and-pp.c" %t.d

tools/clang-cc/DependencyFile.cpp

@@ -35,10 +35,6 @@ class VISIBILITY_HIDDEN DependencyFileCallback : public PPCallbacks {
   std::vector<std::string> Targets;
   llvm::raw_ostream *OS;
 
-  // FIXME: This functionality should be moved into a common class for
-  // chaining callbacks.
-  PPCallbacks *PrevCallbacks;
-
 private:
   bool FileMatchesDepCriteria(const char *Filename,
                               SrcMgr::CharacteristicKind FileType);
@@ -47,14 +43,11 @@ private:
 public:
   DependencyFileCallback(const Preprocessor *_PP, 
                          llvm::raw_ostream *_OS, 
-                         const std::vector<std::string> &_Targets,
-                         PPCallbacks *_PrevCallbacks)
-    : PP(_PP), Targets(_Targets), OS(_OS), PrevCallbacks(_PrevCallbacks) {
+                         const std::vector<std::string> &_Targets)
+    : PP(_PP), Targets(_Targets), OS(_OS) {
   }
 
   ~DependencyFileCallback() {
-    if (PrevCallbacks)
-      delete PrevCallbacks;
     OutputDependencyFile();
     OS->flush();
     delete OS;
@@ -62,32 +55,6 @@ public:
 
   virtual void FileChanged(SourceLocation Loc, FileChangeReason Reason,
                            SrcMgr::CharacteristicKind FileType);
-
-  virtual void Ident(SourceLocation Loc, const std::string &str) {
-    if (PrevCallbacks)
-      PrevCallbacks->Ident(Loc, str);
-  }
-  
-  virtual void PragmaComment(SourceLocation Loc, const IdentifierInfo *Kind, 
-                             const std::string &Str) {
-    if (PrevCallbacks)
-      PrevCallbacks->PragmaComment(Loc, Kind, Str);
-  }
-  
-  virtual void MacroExpands(const Token &Id, const MacroInfo* MI) {
-    if (PrevCallbacks)
-      PrevCallbacks->MacroExpands(Id, MI);
-  }
-  
-  virtual void MacroDefined(const IdentifierInfo *II, const MacroInfo *MI) {
-    if (PrevCallbacks)
-      PrevCallbacks->MacroDefined(II, MI);
-  }
-
-  virtual void MacroUndefined(const IdentifierInfo *II, const MacroInfo *MI) {
-    if (PrevCallbacks)
-      PrevCallbacks->MacroUndefined(II, MI);
-  }
 };
 }
 
@@ -135,13 +102,8 @@ bool clang::CreateDependencyFileGen(Preprocessor *PP,
     }
   }
 
-  // Claim any previous callbacks.
-  PPCallbacks *Prev = PP->getPPCallbacks();
-  if (Prev)
-    PP->setPPCallbacks(0);
-
   DependencyFileCallback *PPDep = 
-    new DependencyFileCallback(PP, OS, DependencyTargets, Prev);
+    new DependencyFileCallback(PP, OS, DependencyTargets);
   PP->setPPCallbacks(PPDep);
   return true;
 }
@@ -162,9 +124,6 @@ bool DependencyFileCallback::FileMatchesDepCriteria(const char *Filename,
 void DependencyFileCallback::FileChanged(SourceLocation Loc,
                                          FileChangeReason Reason,
                                          SrcMgr::CharacteristicKind FileType) {
-  if (PrevCallbacks)
-    PrevCallbacks->FileChanged(Loc, Reason, FileType);
-
   if (Reason != PPCallbacks::EnterFile)
     return;