[analyzer] Utility to match function calls.

This patch adds a small utility to match function calls. This utility abstracts away the mutable keywords and the lazy initialization and caching logic of identifiers from the checkers. The SimpleStreamChecker is ported over this utility within this patch to show the reduction of code and to test this change.

Differential Revision: http://reviews.llvm.org/D15921


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@258572 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 14 insertions, 21 deletions

diff --git a/lib/StaticAnalyzer/Checkers/SimpleStreamChecker.cpp b/lib/StaticAnalyzer/Checkers/SimpleStreamChecker.cpp
index 7026a2ec16..62e6f02fe3 100644
--- a/lib/StaticAnalyzer/Checkers/SimpleStreamChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/SimpleStreamChecker.cpp
@@ -51,14 +51,11 @@ class SimpleStreamChecker : public Checker<check::PostCall,
                                            check::PreCall,
                                            check::DeadSymbols,
                                            check::PointerEscape> {
-
-  mutable IdentifierInfo *IIfopen, *IIfclose;
+  CallDescription OpenFn, CloseFn;
 
   std::unique_ptr<BugType> DoubleCloseBugType;
   std::unique_ptr<BugType> LeakBugType;
 
-  void initIdentifierInfo(ASTContext &Ctx) const;
-
   void reportDoubleClose(SymbolRef FileDescSym,
                          const CallEvent &Call,
                          CheckerContext &C) const;
@@ -106,7 +103,7 @@ public:
 } // end anonymous namespace
 
 SimpleStreamChecker::SimpleStreamChecker()
-    : IIfopen(nullptr), IIfclose(nullptr) {
+    : OpenFn("fopen"), CloseFn("fclose", 1) {
   // Initialize the bug types.
   DoubleCloseBugType.reset(
       new BugType(this, "Double fclose", "Unix Stream API Error"));
@@ -119,12 +116,10 @@ SimpleStreamChecker::SimpleStreamChecker()
 
 void SimpleStreamChecker::checkPostCall(const CallEvent &Call,
                                         CheckerContext &C) const {
-  initIdentifierInfo(C.getASTContext());
-
   if (!Call.isGlobalCFunction())
     return;
 
-  if (Call.getCalleeIdentifier() != IIfopen)
+  if (!Call.isCalled(OpenFn))
     return;
 
   // Get the symbolic value corresponding to the file handle.
@@ -140,15 +135,10 @@ void SimpleStreamChecker::checkPostCall(const CallEvent &Call,
 
 void SimpleStreamChecker::checkPreCall(const CallEvent &Call,
                                        CheckerContext &C) const {
-  initIdentifierInfo(C.getASTContext());
-
   if (!Call.isGlobalCFunction())
     return;
 
-  if (Call.getCalleeIdentifier() != IIfclose)
-    return;
-
-  if (Call.getNumArgs() != 1)
+  if (!Call.isCalled(CloseFn))
     return;
 
   // Get the symbolic value corresponding to the file handle.
@@ -275,13 +265,6 @@ SimpleStreamChecker::checkPointerEscape(ProgramStateRef State,
   return State;
 }
 
-void SimpleStreamChecker::initIdentifierInfo(ASTContext &Ctx) const {
-  if (IIfopen)
-    return;
-  IIfopen = &Ctx.Idents.get("fopen");
-  IIfclose = &Ctx.Idents.get("fclose");
-}
-
 void ento::registerSimpleStreamChecker(CheckerManager &mgr) {
   mgr.registerChecker<SimpleStreamChecker>();
 }
diff --git a/lib/StaticAnalyzer/Core/CallEvent.cpp b/lib/StaticAnalyzer/Core/CallEvent.cpp
index 69af09b25b..59b90b5ce9 100644
--- a/lib/StaticAnalyzer/Core/CallEvent.cpp
+++ b/lib/StaticAnalyzer/Core/CallEvent.cpp
@@ -210,6 +210,16 @@ ProgramPoint CallEvent::getProgramPoint(bool IsPreVisit,
   return PostImplicitCall(D, Loc, getLocationContext(), Tag);
 }
 
+bool CallEvent::isCalled(const CallDescription &CD) const {
+  assert(getKind() != CE_ObjCMessage && "Obj-C methods are not supported");
+  if (!CD.II)
+    CD.II = &getState()->getStateManager().getContext().Idents.get(CD.FuncName);
+  if (getCalleeIdentifier() != CD.II)
+    return false;
+  return (CD.RequiredArgs == CallDescription::NoArgRequirement ||
+          CD.RequiredArgs == getNumArgs());
+}
+
 SVal CallEvent::getArgSVal(unsigned Index) const {
   const Expr *ArgE = getArgExpr(Index);
   if (!ArgE)