[code-complete] Introduce CodeCompletionTUInfo which will be used for caching

code-completion related strings specific to a translation unit (ASTContext and related data)

CodeCompletionAllocator does such limited caching, by caching the name assigned
to a DeclContext*, but that is not the appropriate place since that object has
a lifetime that can extend beyond that of an ASTContext.

Introduce CodeCompletionTUInfo which will be always tied to a translation unit
to do this kind of caching and move the caching of CodeCompletionAllocator into this
object, and propagate it to all the places where it will be needed.

The plan is to extend the caching where appropriate, using CodeCompletionTUInfo,
to avoid re-calculating code-completion strings.

Part of rdar://10796159.

llvm-svn: 154408

1 files changed, 69 insertions, 52 deletions

diff --git a/clang/lib/Sema/CodeCompleteConsumer.cpp b/clang/lib/Sema/CodeCompleteConsumer.cpp
index dbc9b00..ce9bbb9 100644
--- a/clang/lib/Sema/CodeCompleteConsumer.cpp
+++ b/clang/lib/Sema/CodeCompleteConsumer.cpp
@@ -267,8 +267,70 @@ const char *CodeCompletionAllocator::CopyString(Twine String) {
   return CopyString(String.toStringRef(Data));
 }
 
+StringRef CodeCompletionTUInfo::getParentName(DeclContext *DC) {
+  NamedDecl *ND = dyn_cast<NamedDecl>(DC);
+  if (!ND)
+    return StringRef();
+  
+  // Check whether we've already cached the parent name.
+  StringRef &CachedParentName = ParentNames[DC];
+  if (!CachedParentName.empty())
+    return CachedParentName;
+
+  // If we already processed this DeclContext and assigned empty to it, the
+  // data pointer will be non-null.
+  if (CachedParentName.data() != 0)
+    return StringRef();
+
+  // Find the interesting names.
+  llvm::SmallVector<DeclContext *, 2> Contexts;
+  while (DC && !DC->isFunctionOrMethod()) {
+    if (NamedDecl *ND = dyn_cast<NamedDecl>(DC)) {
+      if (ND->getIdentifier())
+        Contexts.push_back(DC);
+    }
+    
+    DC = DC->getParent();
+  }
+
+  {
+    llvm::SmallString<128> S;
+    llvm::raw_svector_ostream OS(S);
+    bool First = true;
+    for (unsigned I = Contexts.size(); I != 0; --I) {
+      if (First)
+        First = false;
+      else {
+        OS << "::";
+      }
+      
+      DeclContext *CurDC = Contexts[I-1];
+      if (ObjCCategoryImplDecl *CatImpl = dyn_cast<ObjCCategoryImplDecl>(CurDC))
+        CurDC = CatImpl->getCategoryDecl();
+      
+      if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(CurDC)) {
+        ObjCInterfaceDecl *Interface = Cat->getClassInterface();
+        if (!Interface) {
+          // Assign an empty StringRef but with non-null data to distinguish
+          // between empty because we didn't process the DeclContext yet.
+          CachedParentName = StringRef((const char *)~0U, 0);
+          return StringRef();
+        }
+        
+        OS << Interface->getName() << '(' << Cat->getName() << ')';
+      } else {
+        OS << cast<NamedDecl>(CurDC)->getName();
+      }
+    }
+    
+    CachedParentName = AllocatorRef->CopyString(OS.str());
+  }
+
+  return CachedParentName;
+}
+
 CodeCompletionString *CodeCompletionBuilder::TakeString() {
-  void *Mem = Allocator.Allocate(
+  void *Mem = getAllocator().Allocate(
                   sizeof(CodeCompletionString) + sizeof(Chunk) * Chunks.size()
                                     + sizeof(const char *) * Annotations.size(),
                                  llvm::alignOf<CodeCompletionString>());
@@ -329,54 +391,7 @@ void CodeCompletionBuilder::addParentContext(DeclContext *DC) {
     return;
   
   ParentKind = getCursorKindForDecl(ND);
-  
-  // Check whether we've already cached the parent name.
-  StringRef &CachedParentName = Allocator.getParentNames()[DC];
-  if (!CachedParentName.empty()) {
-    ParentName = CachedParentName;
-    return;
-  }
-
-  // Find the interesting names.
-  llvm::SmallVector<DeclContext *, 2> Contexts;
-  while (DC && !DC->isFunctionOrMethod()) {
-    if (NamedDecl *ND = dyn_cast<NamedDecl>(DC)) {
-      if (ND->getIdentifier())
-        Contexts.push_back(DC);
-    }
-    
-    DC = DC->getParent();
-  }
-
-  {
-    llvm::SmallString<128> S;
-    llvm::raw_svector_ostream OS(S);
-    bool First = true;
-    for (unsigned I = Contexts.size(); I != 0; --I) {
-      if (First)
-        First = false;
-      else {
-        OS << "::";
-      }
-      
-      DeclContext *CurDC = Contexts[I-1];
-      if (ObjCCategoryImplDecl *CatImpl = dyn_cast<ObjCCategoryImplDecl>(CurDC))
-        CurDC = CatImpl->getCategoryDecl();
-      
-      if (ObjCCategoryDecl *Cat = dyn_cast<ObjCCategoryDecl>(CurDC)) {
-        ObjCInterfaceDecl *Interface = Cat->getClassInterface();
-        if (!Interface)
-          return;
-        
-        OS << Interface->getName() << '(' << Cat->getName() << ')';
-      } else {
-        OS << cast<NamedDecl>(CurDC)->getName();
-      }
-    }
-    
-    ParentName = Allocator.CopyString(OS.str());
-    CachedParentName = ParentName;
-  }
+  ParentName = getCodeCompletionTUInfo().getParentName(DC);
 }
 
 unsigned CodeCompletionResult::getPriorityFromDecl(NamedDecl *ND) {
@@ -458,7 +473,8 @@ PrintingCodeCompleteConsumer::ProcessCodeCompleteResults(Sema &SemaRef,
       if (Results[I].Hidden)
         OS << " (Hidden)";
       if (CodeCompletionString *CCS 
-            = Results[I].CreateCodeCompletionString(SemaRef, Allocator)) {
+            = Results[I].CreateCodeCompletionString(SemaRef, getAllocator(),
+                                                    CCTUInfo)) {
         OS << " : " << CCS->getAsString();
       }
         
@@ -472,7 +488,8 @@ PrintingCodeCompleteConsumer::ProcessCodeCompleteResults(Sema &SemaRef,
     case CodeCompletionResult::RK_Macro: {
       OS << Results[I].Macro->getName();
       if (CodeCompletionString *CCS 
-            = Results[I].CreateCodeCompletionString(SemaRef, Allocator)) {
+            = Results[I].CreateCodeCompletionString(SemaRef, getAllocator(),
+                                                    CCTUInfo)) {
         OS << " : " << CCS->getAsString();
       }
       OS << '\n';
@@ -496,7 +513,7 @@ PrintingCodeCompleteConsumer::ProcessOverloadCandidates(Sema &SemaRef,
   for (unsigned I = 0; I != NumCandidates; ++I) {
     if (CodeCompletionString *CCS
           = Candidates[I].CreateSignatureString(CurrentArg, SemaRef,
-                                                Allocator)) {
+                                                getAllocator(), CCTUInfo)) {
       OS << "OVERLOAD: " << CCS->getAsString() << "\n";
     }
   }