1 files changed, 146 insertions, 19 deletions

diff --git a/lib/Sema/IdentifierResolver.cpp b/lib/Sema/IdentifierResolver.cpp
index a643267085..812f5d64fa 100644
--- a/lib/Sema/IdentifierResolver.cpp
+++ b/lib/Sema/IdentifierResolver.cpp
@@ -15,7 +15,10 @@
 #include "clang/Sema/IdentifierResolver.h"
 #include "clang/Sema/Scope.h"
 #include "clang/AST/Decl.h"
+#include "clang/AST/DeclObjC.h"
 #include "clang/Basic/LangOptions.h"
+#include "clang/Lex/ExternalPreprocessorSource.h"
+#include "clang/Lex/Preprocessor.h"
 
 using namespace clang;
 
@@ -93,9 +96,11 @@ IdentifierResolver::IdDeclInfo::ReplaceDecl(NamedDecl *Old, NamedDecl *New) {
 // IdentifierResolver Implementation
 //===----------------------------------------------------------------------===//
 
-IdentifierResolver::IdentifierResolver(const LangOptions &langOpt)
-    : LangOpt(langOpt), IdDeclInfos(new IdDeclInfoMap) {
+IdentifierResolver::IdentifierResolver(Preprocessor &PP)
+  : LangOpt(PP.getLangOptions()), PP(PP),
+    IdDeclInfos(new IdDeclInfoMap) {
 }
+
 IdentifierResolver::~IdentifierResolver() {
   delete IdDeclInfos;
 }
@@ -146,7 +151,7 @@ bool IdentifierResolver::isDeclInScope(Decl *D, DeclContext *Ctx,
 void IdentifierResolver::AddDecl(NamedDecl *D) {
   DeclarationName Name = D->getDeclName();
   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
-    II->setIsFromAST(false);
+    updatingIdentifier(*II);
 
   void *Ptr = Name.getFETokenInfo<void>();
 
@@ -170,6 +175,9 @@ void IdentifierResolver::AddDecl(NamedDecl *D) {
 
 void IdentifierResolver::InsertDeclAfter(iterator Pos, NamedDecl *D) {
   DeclarationName Name = D->getDeclName();
+  if (IdentifierInfo *II = Name.getAsIdentifierInfo())
+    updatingIdentifier(*II);
+  
   void *Ptr = Name.getFETokenInfo<void>();
   
   if (!Ptr) {
@@ -195,7 +203,8 @@ void IdentifierResolver::InsertDeclAfter(iterator Pos, NamedDecl *D) {
   }
 
   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
-    II->setIsFromAST(false);
+    if (II->isFromAST())
+      II->setChangedSinceDeserialization();
   
   // General case: insert the declaration at the appropriate point in the 
   // list, which already has at least two elements.
@@ -212,7 +221,7 @@ void IdentifierResolver::RemoveDecl(NamedDecl *D) {
   assert(D && "null param passed");
   DeclarationName Name = D->getDeclName();
   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
-    II->setIsFromAST(false);
+    updatingIdentifier(*II);
 
   void *Ptr = Name.getFETokenInfo<void>();
 
@@ -233,7 +242,7 @@ bool IdentifierResolver::ReplaceDecl(NamedDecl *Old, NamedDecl *New) {
 
   DeclarationName Name = Old->getDeclName();
   if (IdentifierInfo *II = Name.getAsIdentifierInfo())
-    II->setIsFromAST(false);
+    updatingIdentifier(*II);
 
   void *Ptr = Name.getFETokenInfo<void>();
 
@@ -254,6 +263,9 @@ bool IdentifierResolver::ReplaceDecl(NamedDecl *Old, NamedDecl *New) {
 /// begin - Returns an iterator for decls with name 'Name'.
 IdentifierResolver::iterator
 IdentifierResolver::begin(DeclarationName Name) {
+  if (IdentifierInfo *II = Name.getAsIdentifierInfo())
+    readingIdentifier(*II);
+    
   void *Ptr = Name.getFETokenInfo<void>();
   if (!Ptr) return end();
 
@@ -269,27 +281,142 @@ IdentifierResolver::begin(DeclarationName Name) {
   return end();
 }
 
-void IdentifierResolver::AddDeclToIdentifierChain(IdentifierInfo *II,
-                                                  NamedDecl *D) {
-  II->setIsFromAST(false);
-  void *Ptr = II->getFETokenInfo<void>();
+namespace {
+  enum DeclMatchKind {
+    DMK_Different,
+    DMK_Replace,
+    DMK_Ignore
+  };
+}
 
-  if (!Ptr) {
-    II->setFETokenInfo(D);
-    return;
+/// \brief Compare two declarations to see whether they are different or,
+/// if they are the same, whether the new declaration should replace the 
+/// existing declaration.
+static DeclMatchKind compareDeclarations(NamedDecl *Existing, NamedDecl *New) {
+  // If the declarations are identical, ignore the new one.
+  if (Existing == New)
+    return DMK_Ignore;
+
+  // If the declarations have different kinds, they're obviously different.
+  if (Existing->getKind() != New->getKind())
+    return DMK_Different;
+
+  // If the declarations are redeclarations of each other, keep the newest one.
+  if (Existing->getCanonicalDecl() == New->getCanonicalDecl()) {
+    // If the existing declaration is somewhere in the previous declaration
+    // chain of the new declaration, then prefer the new declaration.
+    for (Decl::redecl_iterator RD = New->redecls_begin(), 
+                            RDEnd = New->redecls_end();
+         RD != RDEnd; ++RD) {
+      if (*RD == Existing)
+        return DMK_Replace;
+        
+      if (RD->isCanonicalDecl())
+        break;
+    }
+    
+    return DMK_Ignore;
   }
+  
+  // If the declarations are both Objective-C classes, and one is a forward
+  // declaration and the other is not, take the full definition.
+  // FIXME: At some point, we'll actually have to detect collisions better.
+  // This logic, however, belongs in the AST reader, not here.
+  if (ObjCInterfaceDecl *ExistingIFace = dyn_cast<ObjCInterfaceDecl>(Existing))
+    if (ObjCInterfaceDecl *NewIFace = dyn_cast<ObjCInterfaceDecl>(New))
+      if (ExistingIFace->isForwardDecl() != NewIFace->isForwardDecl())
+        return ExistingIFace->isForwardDecl()? DMK_Replace : DMK_Ignore;
+        
+  return DMK_Different;
+}
 
+bool IdentifierResolver::tryAddTopLevelDecl(NamedDecl *D, DeclarationName Name){
+  if (IdentifierInfo *II = Name.getAsIdentifierInfo())
+    updatingIdentifier(*II);
+  
+  void *Ptr = Name.getFETokenInfo<void>();
+    
+  if (!Ptr) {
+    Name.setFETokenInfo(D);
+    return true;
+  }
+  
   IdDeclInfo *IDI;
-
+  
   if (isDeclPtr(Ptr)) {
-    II->setFETokenInfo(NULL);
-    IDI = &(*IdDeclInfos)[II];
     NamedDecl *PrevD = static_cast<NamedDecl*>(Ptr);
-    IDI->AddDecl(PrevD);
-  } else
-    IDI = toIdDeclInfo(Ptr);
+    
+    switch (compareDeclarations(PrevD, D)) {
+    case DMK_Different:
+      break;
+      
+    case DMK_Ignore:
+      return false;
+      
+    case DMK_Replace:
+      Name.setFETokenInfo(D);
+      return true;
+    }
+    
+    Name.setFETokenInfo(NULL);
+    IDI = &(*IdDeclInfos)[Name];
+    
+    // If the existing declaration is not visible in translation unit scope,
+    // then add the new top-level declaration first.
+    if (!PrevD->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
+      IDI->AddDecl(D);
+      IDI->AddDecl(PrevD);
+    } else {
+      IDI->AddDecl(PrevD);
+      IDI->AddDecl(D);
+    }
+    return true;
+  } 
+  
+  IDI = toIdDeclInfo(Ptr);
 
+  // See whether this declaration is identical to any existing declarations.
+  // If not, find the right place to insert it.
+  for (IdDeclInfo::DeclsTy::iterator I = IDI->decls_begin(), 
+                                  IEnd = IDI->decls_end();
+       I != IEnd; ++I) {
+    
+    switch (compareDeclarations(*I, D)) {
+    case DMK_Different:
+      break;
+      
+    case DMK_Ignore:
+      return false;
+      
+    case DMK_Replace:
+      *I = D;
+      return true;
+    }
+    
+    if (!(*I)->getDeclContext()->getRedeclContext()->isTranslationUnit()) {
+      // We've found a declaration that is not visible from the translation
+      // unit (it's in an inner scope). Insert our declaration here.
+      IDI->InsertDecl(I, D);
+      return true;
+    }
+  }
+  
+  // Add the declaration to the end.
   IDI->AddDecl(D);
+  return true;
+}
+
+void IdentifierResolver::readingIdentifier(IdentifierInfo &II) {
+  if (II.isOutOfDate())
+    PP.getExternalSource()->updateOutOfDateIdentifier(II);  
+}
+
+void IdentifierResolver::updatingIdentifier(IdentifierInfo &II) {
+  if (II.isOutOfDate())
+    PP.getExternalSource()->updateOutOfDateIdentifier(II);
+  
+  if (II.isFromAST())
+    II.setChangedSinceDeserialization();
 }
 
 //===----------------------------------------------------------------------===//