Allocate CodeCompletionString and all of its components in a

BumpPtrAllocator, rather than manually new/delete'ing them. This
optimization also allows us to avoid allocating memory for and copying
constant strings (e.g., "return", "class").

This also required embedding the priority and availability of results
within the code completion string, to avoid extra memory allocation
within libclang.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124673 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 96 insertions, 61 deletions

diff --git a/include/clang/Sema/CodeCompleteConsumer.h b/include/clang/Sema/CodeCompleteConsumer.h
index 5cdcc27b67..9daefd72a5 100644
--- a/include/clang/Sema/CodeCompleteConsumer.h
+++ b/include/clang/Sema/CodeCompleteConsumer.h
@@ -17,8 +17,8 @@
 #include "clang/AST/CanonicalType.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Allocator.h"
 #include "clang-c/Index.h"
-#include <memory>
 #include <string>
 
 namespace llvm {
@@ -354,119 +354,149 @@ public:
     
     Chunk() : Kind(CK_Text), Text(0) { }
     
-    Chunk(ChunkKind Kind, llvm::StringRef Text = "");
+    Chunk(ChunkKind Kind, const char *Text = "");
     
     /// \brief Create a new text chunk.
-    static Chunk CreateText(llvm::StringRef Text);
+    static Chunk CreateText(const char *Text);
 
     /// \brief Create a new optional chunk.
-    static Chunk CreateOptional(std::auto_ptr<CodeCompletionString> Optional);
+    static Chunk CreateOptional(CodeCompletionString *Optional);
 
     /// \brief Create a new placeholder chunk.
-    static Chunk CreatePlaceholder(llvm::StringRef Placeholder);
+    static Chunk CreatePlaceholder(const char *Placeholder);
 
     /// \brief Create a new informative chunk.
-    static Chunk CreateInformative(llvm::StringRef Informative);
+    static Chunk CreateInformative(const char *Informative);
 
     /// \brief Create a new result type chunk.
-    static Chunk CreateResultType(llvm::StringRef ResultType);
+    static Chunk CreateResultType(const char *ResultType);
 
     /// \brief Create a new current-parameter chunk.
-    static Chunk CreateCurrentParameter(llvm::StringRef CurrentParameter);
-
-    /// \brief Clone the given chunk.
-    Chunk Clone() const;
-    
-    /// \brief Destroy this chunk, deallocating any memory it owns.
-    void Destroy();
+    static Chunk CreateCurrentParameter(const char *CurrentParameter);
   };
   
 private:
-  /// \brief The chunks stored in this string.
-  llvm::SmallVector<Chunk, 4> Chunks;
+  /// \brief The number of chunks stored in this string.
+  unsigned NumChunks;
+  
+  /// \brief The priority of this code-completion string.
+  unsigned Priority : 30;
+  
+  /// \brief The availability of this code-completion result.
+  CXAvailabilityKind Availability : 2;
   
   CodeCompletionString(const CodeCompletionString &); // DO NOT IMPLEMENT
   CodeCompletionString &operator=(const CodeCompletionString &); // DITTO
   
-public:
-  CodeCompletionString() { }
-  ~CodeCompletionString() { clear(); }
+  CodeCompletionString(const Chunk *Chunks, unsigned NumChunks,
+                       unsigned Priority, CXAvailabilityKind Availability);
+  ~CodeCompletionString() { }
   
-  typedef llvm::SmallVector<Chunk, 4>::const_iterator iterator;
-  iterator begin() const { return Chunks.begin(); }
-  iterator end() const { return Chunks.end(); }
-  bool empty() const { return Chunks.empty(); }
-  unsigned size() const { return Chunks.size(); }
-  void clear();
+  friend class CodeCompletionBuilder;
+  friend class CodeCompletionResult;
   
-  Chunk &operator[](unsigned I) {
+public:
+  typedef const Chunk *iterator;
+  iterator begin() const { return reinterpret_cast<const Chunk *>(this + 1); }
+  iterator end() const { return begin() + NumChunks; }
+  bool empty() const { return NumChunks == 0; }
+  unsigned size() const { return NumChunks; }
+  
+  const Chunk &operator[](unsigned I) const {
     assert(I < size() && "Chunk index out-of-range");
-    return Chunks[I];
+    return begin()[I];
   }
+  
+  /// \brief Returns the text in the TypedText chunk.
+  const char *getTypedText() const;
 
-  const Chunk &operator[](unsigned I) const {
-    assert(I < size() && "Chunk index out-of-range");
-    return Chunks[I];
+  /// \brief Retrieve the priority of this code completion result.
+  unsigned getPriority() const { return Priority; }
+  
+  /// \brief Reteirve the availability of this code completion result.
+  unsigned getAvailability() const { return Availability; }
+  
+  /// \brief Retrieve a string representation of the code completion string,
+  /// which is mainly useful for debugging.
+  std::string getAsString() const;   
+};
+
+/// \brief A builder class used to construct new code-completion strings.
+class CodeCompletionBuilder {
+public:  
+  typedef CodeCompletionString::Chunk Chunk;
+  
+private:
+  llvm::BumpPtrAllocator &Allocator;
+  unsigned Priority;
+  CXAvailabilityKind Availability;
+  
+  /// \brief The chunks stored in this string.
+  llvm::SmallVector<Chunk, 4> Chunks;
+  
+public:
+  CodeCompletionBuilder(llvm::BumpPtrAllocator &Allocator) 
+    : Allocator(Allocator), Priority(0), Availability(CXAvailability_Available){
   }
   
+  CodeCompletionBuilder(llvm::BumpPtrAllocator &Allocator,
+                        unsigned Priority, CXAvailabilityKind Availability) 
+    : Allocator(Allocator), Priority(Priority), Availability(Availability) { }
+
+  /// \brief Retrieve the allocator into which the code completion
+  /// strings will be 
+  llvm::BumpPtrAllocator &getAllocator() const { return Allocator; }
+  
+  /// \brief Take the resulting completion string. 
+  ///
+  /// This operation can only be performed once.
+  CodeCompletionString *TakeString();
+  
   /// \brief Add a new typed-text chunk.
   /// The text string will be copied.
-  void AddTypedTextChunk(llvm::StringRef Text) { 
-    Chunks.push_back(Chunk(CK_TypedText, Text));
+  void AddTypedTextChunk(const char *Text) { 
+    Chunks.push_back(Chunk(CodeCompletionString::CK_TypedText, Text));
   }
   
   /// \brief Add a new text chunk.
   /// The text string will be copied.
-  void AddTextChunk(llvm::StringRef Text) { 
+  void AddTextChunk(const char *Text) { 
     Chunks.push_back(Chunk::CreateText(Text)); 
   }
   
   /// \brief Add a new optional chunk.
-  void AddOptionalChunk(std::auto_ptr<CodeCompletionString> Optional) {
+  void AddOptionalChunk(CodeCompletionString *Optional) {
     Chunks.push_back(Chunk::CreateOptional(Optional));
   }
   
   /// \brief Add a new placeholder chunk.
   /// The placeholder text will be copied.
-  void AddPlaceholderChunk(llvm::StringRef Placeholder) {
+  void AddPlaceholderChunk(const char *Placeholder) {
     Chunks.push_back(Chunk::CreatePlaceholder(Placeholder));
   }
-
+  
   /// \brief Add a new informative chunk.
   /// The text will be copied.
-  void AddInformativeChunk(llvm::StringRef Text) {
+  void AddInformativeChunk(const char *Text) {
     Chunks.push_back(Chunk::CreateInformative(Text));
   }
-
+  
   /// \brief Add a new result-type chunk.
   /// The text will be copied.
-  void AddResultTypeChunk(llvm::StringRef ResultType) {
+  void AddResultTypeChunk(const char *ResultType) {
     Chunks.push_back(Chunk::CreateResultType(ResultType));
   }
   
   /// \brief Add a new current-parameter chunk.
   /// The text will be copied.
-  void AddCurrentParameterChunk(llvm::StringRef CurrentParameter) {
+  void AddCurrentParameterChunk(const char *CurrentParameter) {
     Chunks.push_back(Chunk::CreateCurrentParameter(CurrentParameter));
   }
   
   /// \brief Add a new chunk.
   void AddChunk(Chunk C) { Chunks.push_back(C); }
-  
-  /// \brief Returns the text in the TypedText chunk.
-  const char *getTypedText() const;
-
-  /// \brief Retrieve a string representation of the code completion string,
-  /// which is mainly useful for debugging.
-  std::string getAsString() const; 
-  
-  /// \brief Clone this code-completion string.
-  ///
-  /// \param Result If non-NULL, points to an empty code-completion
-  /// result that will be given a cloned copy of
-  CodeCompletionString *Clone(CodeCompletionString *Result = 0) const;
 };
-
+  
 /// \brief Captures a result of code completion.
 class CodeCompletionResult {
 public:
@@ -597,13 +627,10 @@ public:
   ///
   /// \param S The semantic analysis that created the result.
   ///
-  /// \param Result If non-NULL, the already-allocated, empty
-  /// code-completion string that will be populated with the
-  /// appropriate code completion string for this result.
+  /// \param Allocator The allocator that will be used to allocate the
+  /// string itself.
   CodeCompletionString *CreateCodeCompletionString(Sema &S,
-                                           CodeCompletionString *Result = 0);
-    
-  void Destroy();
+                                             llvm::BumpPtrAllocator &Allocator);
     
   /// \brief Determine a base priority for the given declaration.
   static unsigned getPriorityFromDecl(NamedDecl *ND);
@@ -715,7 +742,7 @@ public:
     /// signature of this overload candidate.
     CodeCompletionString *CreateSignatureString(unsigned CurrentArg, 
                                                 Sema &S,
-                                        CodeCompletionString *Result = 0) const;    
+                                      llvm::BumpPtrAllocator &Allocator) const;
   };
   
   CodeCompleteConsumer() : IncludeMacros(false), IncludeCodePatterns(false),
@@ -761,6 +788,10 @@ public:
                                          OverloadCandidate *Candidates,
                                          unsigned NumCandidates) { }
   //@}
+  
+  /// \brief Retrieve the allocator that will be used to allocate
+  /// code completion strings.
+  virtual llvm::BumpPtrAllocator &getAllocator() = 0;
 };
 
 /// \brief A simple code-completion consumer that prints the results it 
@@ -769,6 +800,8 @@ class PrintingCodeCompleteConsumer : public CodeCompleteConsumer {
   /// \brief The raw output stream.
   llvm::raw_ostream &OS;
     
+  llvm::BumpPtrAllocator Allocator;
+  
 public:
   /// \brief Create a new printing code-completion consumer that prints its
   /// results to the given raw output stream.
@@ -787,6 +820,8 @@ public:
   virtual void ProcessOverloadCandidates(Sema &S, unsigned CurrentArg,
                                          OverloadCandidate *Candidates,
                                          unsigned NumCandidates);  
+  
+  virtual llvm::BumpPtrAllocator &getAllocator() { return Allocator; }
 };
   
 } // end namespace clang