[cfe-commits] r116869 - in /cfe/trunk: include/clang/Lex/Preprocessor.h lib/Lex/PPDirectives.cpp lib/Lex/Preprocessor.cpp

[Ted Kremenek]

Author: kremenek
Date: Tue Oct 19 17:15:20 2010
New Revision: 116869

URL: http://llvm.org/viewvc/llvm-project?rev=116869&view=rev
Log:
Really^2 fix <rdar://problem/8361834>, this time without crashing.

Now MICache is a linked list (per the FIXME), where we tradeoff between MacroInfo objects being in MICache
and MIChainHead.  MacroInfo objects in the MICache chain are already "Destroy()'ed", so they can be reused.  When
inserting into MICache, we need to remove them from the regular linked list so that they aren't destroyed more than
once.

Modified:
    cfe/trunk/include/clang/Lex/Preprocessor.h
    cfe/trunk/lib/Lex/PPDirectives.cpp
    cfe/trunk/lib/Lex/Preprocessor.cpp

Modified: cfe/trunk/include/clang/Lex/Preprocessor.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Lex/Preprocessor.h?rev=116869&r1=116868&r2=116869&view=diff
==============================================================================
--- cfe/trunk/include/clang/Lex/Preprocessor.h (original)
+++ cfe/trunk/include/clang/Lex/Preprocessor.h Tue Oct 19 17:15:20 2010
@@ -195,11 +195,6 @@
   /// to the actual definition of the macro.
   llvm::DenseMap<IdentifierInfo*, MacroInfo*> Macros;
 
-  /// MICache - A "freelist" of MacroInfo objects that can be reused for quick
-  /// allocation.
-  /// FIXME: why not use a singly linked list?
-  std::vector<MacroInfo*> MICache;
-
   /// MacroArgCache - This is a "freelist" of MacroArg objects that can be
   /// reused for quick allocation.
   MacroArgs *MacroArgCache;
@@ -255,12 +250,17 @@
   struct MacroInfoChain {
     MacroInfo MI;
     MacroInfoChain *Next;
+    MacroInfoChain *Prev;
   };
 
   /// MacroInfos are managed as a chain for easy disposal.  This is the head
   /// of that list.
   MacroInfoChain *MIChainHead;
 
+  /// MICache - A "freelist" of MacroInfo objects that can be reused for quick
+  /// allocation.
+  MacroInfoChain *MICache;
+
 public:
   Preprocessor(Diagnostic &diags, const LangOptions &opts,
                const TargetInfo &target,

Modified: cfe/trunk/lib/Lex/PPDirectives.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/PPDirectives.cpp?rev=116869&r1=116868&r2=116869&view=diff
==============================================================================
--- cfe/trunk/lib/Lex/PPDirectives.cpp (original)
+++ cfe/trunk/lib/Lex/PPDirectives.cpp Tue Oct 19 17:15:20 2010
@@ -28,18 +28,23 @@
 //===----------------------------------------------------------------------===//
 
 MacroInfo *Preprocessor::AllocateMacroInfo() {
-  MacroInfo *MI;
+  MacroInfoChain *MIChain;
 
-  if (!MICache.empty()) {
-    MI = MICache.back();
-    MICache.pop_back();
-  } else {
-    MacroInfoChain *MIChain = BP.Allocate<MacroInfoChain>();
-    MIChain->Next = MIChainHead;
-    MIChainHead = MIChain;
-    MI = &(MIChain->MI);
+  if (MICache) {
+    MIChain = MICache;
+    MICache = MICache->Next;
   }
-  return MI;
+  else {
+    MIChain = BP.Allocate<MacroInfoChain>();
+  }
+
+  MIChain->Next = MIChainHead;
+  MIChain->Prev = 0;
+  if (MIChainHead)
+    MIChainHead->Prev = MIChain;
+  MIChainHead = MIChain;
+
+  return &(MIChain->MI);
 }
 
 MacroInfo *Preprocessor::AllocateMacroInfo(SourceLocation L) {
@@ -57,10 +62,23 @@
 /// ReleaseMacroInfo - Release the specified MacroInfo.  This memory will
 ///  be reused for allocating new MacroInfo objects.
 void Preprocessor::ReleaseMacroInfo(MacroInfo *MI) {
-  MICache.push_back(MI);
-  MI->FreeArgumentList();
-}
+  MacroInfoChain *MIChain = (MacroInfoChain*) MI;
+  if (MacroInfoChain *Prev = MIChain->Prev) {
+    MacroInfoChain *Next = MIChain->Next;
+    Prev->Next = Next;
+    if (Next)
+      Next->Prev = Prev;
+  }
+  else {
+    assert(MIChainHead == MIChain);
+    MIChainHead = MIChain->Next;
+    MIChainHead->Prev = 0;
+  }
+  MIChain->Next = MICache;
+  MICache = MIChain;
 
+  MI->Destroy();
+}
 
 /// DiscardUntilEndOfDirective - Read and discard all tokens remaining on the
 /// current line until the tok::eom token is found.

Modified: cfe/trunk/lib/Lex/Preprocessor.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/Preprocessor.cpp?rev=116869&r1=116868&r2=116869&view=diff
==============================================================================
--- cfe/trunk/lib/Lex/Preprocessor.cpp (original)
+++ cfe/trunk/lib/Lex/Preprocessor.cpp Tue Oct 19 17:15:20 2010
@@ -56,7 +56,8 @@
     SourceMgr(SM), HeaderInfo(Headers), ExternalSource(0),
     Identifiers(opts, IILookup), BuiltinInfo(Target), CodeComplete(0),
     CodeCompletionFile(0), SkipMainFilePreamble(0, true), CurPPLexer(0), 
-    CurDirLookup(0), Callbacks(0), MacroArgCache(0), Record(0), MIChainHead(0) {
+    CurDirLookup(0), Callbacks(0), MacroArgCache(0), Record(0), MIChainHead(0),
+    MICache(0) {
   ScratchBuf = new ScratchBuffer(SourceMgr);
   CounterValue = 0; // __COUNTER__ starts at 0.
   OwnsHeaderSearch = OwnsHeaders;