[libSyntax] Make copyToArenaIfNecessary a method on SyntaxArena

Author: ahoppen

include/swift/Syntax/RawSyntax.h

@@ -120,27 +120,6 @@ using llvm::StringRef;
 #define syntax_assert_token_is(Tok, Kind, Text)
 #endif
 
-namespace {
-/// If the \p Str is not allocated in \p Arena, copy it to \p Arena and adjust
-/// \p Str to point to the string's copy in \p Arena.
-void copyToArenaIfNecessary(
-    StringRef &Str, const swift::RC<swift::syntax::SyntaxArena> &Arena) {
-  if (Str.empty()) {
-    // Empty strings can live wherever they want. Nothing to do.
-    return;
-  }
-  if (Arena->containsPointer(Str.data())) {
-    // String already in arena. Nothing to do.
-    return;
-  }
-  // Copy string to arena
-  char *Data = (char *)Arena->Allocate(Str.size(), alignof(char *));
-  std::uninitialized_copy(Str.begin(), Str.end(), Data);
-  Str = StringRef(Data, Str.size());
-}
-} // namespace
-// end anonymous namespace
-
 namespace swift {
 namespace syntax {
 
@@ -289,9 +268,6 @@ class RawSyntax final
       : Arena(Arena.get()),
         Bits({{unsigned(TextLength), unsigned(Presence), true}}) {
     assert(Arena && "RawSyntax nodes must always be allocated in an arena");
-    copyToArenaIfNecessary(LeadingTrivia, Arena);
-    copyToArenaIfNecessary(Text, Arena);
-    copyToArenaIfNecessary(TrailingTrivia, Arena);
 
     if (Presence == SourcePresence::Missing) {
       assert(TextLength == 0);
@@ -313,6 +289,13 @@ class RawSyntax final
     Bits.Token.TokenLength = Text.size();
     Bits.Token.TrailingTriviaLength = TrailingTrivia.size();
     Bits.Token.TokenKind = unsigned(TokKind);
+
+    Arena->copyStringToArenaIfNecessary(Bits.Token.LeadingTrivia,
+                                        Bits.Token.LeadingTriviaLength);
+    Arena->copyStringToArenaIfNecessary(Bits.Token.TokenText,
+                                        Bits.Token.TokenLength);
+    Arena->copyStringToArenaIfNecessary(Bits.Token.TrailingTrivia,
+                                        Bits.Token.TrailingTriviaLength);
   }
 
   /// Compute the node's text length by summing up the length of its childern

include/swift/Syntax/SyntaxArena.h

@@ -108,6 +108,23 @@ class SyntaxArena : public llvm::ThreadSafeRefCountedBase<SyntaxArena> {
     }
     return getAllocator().identifyObject(Ptr) != llvm::None;
   }
+
+  /// If the \p Data is not allocated in this arena, copy it to this and adjust
+  /// \p Data to point to the string's copy in this arena.
+  void copyStringToArenaIfNecessary(const char *&Data, size_t Length) {
+    if (Length == 0) {
+      // Empty strings can live wherever they want. Nothing to do.
+      return;
+    }
+    if (containsPointer(Data)) {
+      // String already in arena. Nothing to do.
+      return;
+    }
+    // Copy string to arena
+    char *ArenaData = (char *)getAllocator().Allocate<char>(Length);
+    std::memcpy(ArenaData, Data, Length);
+    Data = ArenaData;
+  }
 };
 
 } // namespace syntax

lib/SyntaxParse/SyntaxTreeCreator.cpp

@@ -35,10 +35,9 @@ SyntaxTreeCreator::SyntaxTreeCreator(SourceManager &SM, unsigned bufferID,
       SyntaxCache(syntaxCache),
       TokenCache(new RawSyntaxTokenCache()) {
   StringRef BufferContent = SM.getEntireTextForBuffer(BufferID);
-  char *Data = (char *)Arena->Allocate(BufferContent.size(), alignof(char *));
-  std::uninitialized_copy(BufferContent.begin(), BufferContent.end(), Data);
+  const char *Data = BufferContent.data();
+  Arena->copyStringToArenaIfNecessary(Data, BufferContent.size());
   ArenaSourceBuffer = StringRef(Data, BufferContent.size());
-  assert(ArenaSourceBuffer == BufferContent);
   Arena->setHotUseMemoryRegion(ArenaSourceBuffer.begin(),
                                ArenaSourceBuffer.end());
 }