[cfe-commits] r116842 - in /cfe/trunk: include/clang/Lex/Preprocessor.h lib/Lex/PPDirectives.cpp lib/Lex/Preprocessor.cpp

[Ted Kremenek]

Author: kremenek
Date: Tue Oct 19 13:16:54 2010
New Revision: 116842

URL: http://llvm.org/viewvc/llvm-project?rev=116842&view=rev
Log:
Simplify lifetime management of MacroInfo objects in Preprocessor by having the Preprocessor maintain them in a linked
list of allocated MacroInfos.  This requires only 1 extra pointer per MacroInfo object, and allows us to blow them
away in one place.  This fixes an elusive memory leak with MacroInfos (whose exact location I couldn't still figure
out despite substantial digging).

Fixes <rdar://problem/8361834>.

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=116842&r1=116841&r2=116842&view=diff
==============================================================================
--- cfe/trunk/include/clang/Lex/Preprocessor.h (original)
+++ cfe/trunk/include/clang/Lex/Preprocessor.h Tue Oct 19 13:16:54 2010
@@ -14,6 +14,7 @@
 #ifndef LLVM_CLANG_LEX_PREPROCESSOR_H
 #define LLVM_CLANG_LEX_PREPROCESSOR_H
 
+#include "clang/Lex/MacroInfo.h"
 #include "clang/Lex/Lexer.h"
 #include "clang/Lex/PTHLexer.h"
 #include "clang/Lex/PPCallbacks.h"
@@ -251,6 +252,15 @@
   /// invoked (at which point the last position is popped).
   std::vector<CachedTokensTy::size_type> BacktrackPositions;
 
+  struct MacroInfoChain {
+    MacroInfo MI;
+    MacroInfoChain *Next;
+  };
+
+  /// MacroInfos are managed as a chain for easy disposal.  This is the head
+  /// of that list.
+  MacroInfoChain *MIChainHead;
+
 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=116842&r1=116841&r2=116842&view=diff
==============================================================================
--- cfe/trunk/lib/Lex/PPDirectives.cpp (original)
+++ cfe/trunk/lib/Lex/PPDirectives.cpp Tue Oct 19 13:16:54 2010
@@ -33,8 +33,12 @@
   if (!MICache.empty()) {
     MI = MICache.back();
     MICache.pop_back();
-  } else
-    MI = (MacroInfo*) BP.Allocate<MacroInfo>();
+  } else {
+    MacroInfoChain *MIChain = BP.Allocate<MacroInfoChain>();
+    MIChain->Next = MIChainHead;
+    MIChainHead = MIChain;
+    MI = &(MIChainHead->MI);
+  }
   return MI;
 }
 

Modified: cfe/trunk/lib/Lex/Preprocessor.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/Preprocessor.cpp?rev=116842&r1=116841&r2=116842&view=diff
==============================================================================
--- cfe/trunk/lib/Lex/Preprocessor.cpp (original)
+++ cfe/trunk/lib/Lex/Preprocessor.cpp Tue Oct 19 13:16:54 2010
@@ -56,7 +56,7 @@
     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) {
+    CurDirLookup(0), Callbacks(0), MacroArgCache(0), Record(0), MIChainHead(0) {
   ScratchBuf = new ScratchBuffer(SourceMgr);
   CounterValue = 0; // __COUNTER__ starts at 0.
   OwnsHeaderSearch = OwnsHeaders;
@@ -106,29 +106,10 @@
   }
 
   // Free any macro definitions.
-  for (llvm::DenseMap<IdentifierInfo*, MacroInfo*>::iterator I =
-       Macros.begin(), E = Macros.end(); I != E; ++I) {
-    // We don't need to free the MacroInfo objects directly.  These
-    // will be released when the BumpPtrAllocator 'BP' object gets
-    // destroyed.  We still need to run the dtor, however, to free
-    // memory alocated by MacroInfo.
-    I->second->Destroy();
-    I->first->setHasMacroDefinition(false);
-  }
-  for (std::vector<MacroInfo*>::iterator I = MICache.begin(),
-                                         E = MICache.end(); I != E; ++I) {
-    // We don't need to free the MacroInfo objects directly.  These
-    // will be released when the BumpPtrAllocator 'BP' object gets
-    // destroyed.  We still need to run the dtor, however, to free
-    // memory alocated by MacroInfo.
-    (*I)->Destroy();
-  }
-  for (llvm::DenseMap<IdentifierInfo*, std::vector<MacroInfo*> >::iterator I =
-         PragmaPushMacroInfo.begin(), E = PragmaPushMacroInfo.end(); I!=E; ++I){
-    for (std::vector<MacroInfo*>::iterator I2 = I->second.begin(), E2 = I->second.end();
-         I2 != E2; ++I2) {
-      (*I2)->Destroy();
-    }
+  for (MacroInfoChain *I = MIChainHead ; I ; ) {
+    MacroInfoChain *Next = I->Next;
+    I->MI.Destroy();
+    I = Next;
   }
 
   // Free any cached macro expanders.