[analyzer] Add support for escape of const pointers and use it to allow “newed” pointers to escape

Add a new callback that notifies checkers when a const pointer escapes. Currently, this only works
for const pointers passed as a top level parameter into a function. We need to differentiate the const
pointers escape from regular escape since the content pointed by const pointer will not change;
if it’s a file handle, a file cannot be closed; but delete is allowed on const pointers.

This should suppress several false positives reported by the NewDelete checker on llvm codebase.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@178310 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 2 deletions

diff --git a/include/clang/StaticAnalyzer/Core/CheckerManager.h b/include/clang/StaticAnalyzer/Core/CheckerManager.h
index 4353ebf015..6f99fc1457 100644
--- a/include/clang/StaticAnalyzer/Core/CheckerManager.h
+++ b/include/clang/StaticAnalyzer/Core/CheckerManager.h
@@ -346,12 +346,14 @@ public:
   /// \param Escaped The list of escaped symbols.
   /// \param Call The corresponding CallEvent, if the symbols escape as 
   ///        parameters to the given call.
+  /// \param IsConst Specifies if the pointer is const.
   /// \returns Checkers can modify the state by returning a new one.
   ProgramStateRef 
   runCheckersForPointerEscape(ProgramStateRef State,
                               const InvalidatedSymbols &Escaped,
                               const CallEvent *Call,
-                              PointerEscapeKind Kind);
+                              PointerEscapeKind Kind,
+                              bool IsConst = false);
 
   /// \brief Run checkers for handling assumptions on symbolic values.
   ProgramStateRef runCheckersForEvalAssume(ProgramStateRef state,
@@ -442,7 +444,8 @@ public:
   typedef CheckerFn<ProgramStateRef (ProgramStateRef,
                                      const InvalidatedSymbols &Escaped,
                                      const CallEvent *Call,
-                                     PointerEscapeKind Kind)>
+                                     PointerEscapeKind Kind,
+                                     bool IsConst)>
       CheckPointerEscapeFunc;
   
   typedef CheckerFn<ProgramStateRef (ProgramStateRef,
@@ -487,6 +490,8 @@ public:
 
   void _registerForPointerEscape(CheckPointerEscapeFunc checkfn);
 
+  void _registerForConstPointerEscape(CheckPointerEscapeFunc checkfn);
+
   void _registerForEvalAssume(EvalAssumeFunc checkfn);
 
   void _registerForEvalCall(EvalCallFunc checkfn);