[analyzer] Add checker callback for beginning of function.

Add a checker callback that is called when the analyzer starts analyzing a
function either at the top level or when inlined. This will be used by a
follow-on patch making the DeallocChecker path sensitive.

Differential Revision: http://reviews.llvm.org/D17418

llvm-svn: 261293

4 files changed, 75 insertions, 13 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp b/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp
index 008e8ef31cd..d8382e88691 100644
--- a/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp
+++ b/clang/lib/StaticAnalyzer/Core/CheckerManager.cpp
@@ -377,6 +377,40 @@ void CheckerManager::runCheckersForEndAnalysis(ExplodedGraph &G,
     EndAnalysisCheckers[i](G, BR, Eng);
 }
 
+namespace {
+struct CheckBeginFunctionContext {
+  typedef std::vector<CheckerManager::CheckBeginFunctionFunc> CheckersTy;
+  const CheckersTy &Checkers;
+  ExprEngine &Eng;
+  const ProgramPoint &PP;
+
+  CheckersTy::const_iterator checkers_begin() { return Checkers.begin(); }
+  CheckersTy::const_iterator checkers_end() { return Checkers.end(); }
+
+  CheckBeginFunctionContext(const CheckersTy &Checkers, ExprEngine &Eng,
+                            const ProgramPoint &PP)
+      : Checkers(Checkers), Eng(Eng), PP(PP) {}
+
+  void runChecker(CheckerManager::CheckBeginFunctionFunc checkFn,
+                  NodeBuilder &Bldr, ExplodedNode *Pred) {
+    const ProgramPoint &L = PP.withTag(checkFn.Checker);
+    CheckerContext C(Bldr, Eng, Pred, L);
+
+    checkFn(C);
+  }
+};
+}
+
+void CheckerManager::runCheckersForBeginFunction(ExplodedNodeSet &Dst,
+                                                 const BlockEdge &L,
+                                                 ExplodedNode *Pred,
+                                                 ExprEngine &Eng) {
+  ExplodedNodeSet Src;
+  Src.insert(Pred);
+  CheckBeginFunctionContext C(BeginFunctionCheckers, Eng, L);
+  expandGraphWithCheckers(C, Dst, Src);
+}
+
 /// \brief Run checkers for end of path.
 // Note, We do not chain the checker output (like in expandGraphWithCheckers)
 // for this callback since end of path nodes are expected to be final.
@@ -671,6 +705,10 @@ void CheckerManager::_registerForEndAnalysis(CheckEndAnalysisFunc checkfn) {
   EndAnalysisCheckers.push_back(checkfn);
 }
 
+void CheckerManager::_registerForBeginFunction(CheckBeginFunctionFunc checkfn) {
+  BeginFunctionCheckers.push_back(checkfn);
+}
+
 void CheckerManager::_registerForEndFunction(CheckEndFunctionFunc checkfn) {
   EndFunctionCheckers.push_back(checkfn);
 }
diff --git a/clang/lib/StaticAnalyzer/Core/CoreEngine.cpp b/clang/lib/StaticAnalyzer/Core/CoreEngine.cpp
index 39cf7e77175..c75fb2e763d 100644
--- a/clang/lib/StaticAnalyzer/Core/CoreEngine.cpp
+++ b/clang/lib/StaticAnalyzer/Core/CoreEngine.cpp
@@ -192,10 +192,18 @@ bool CoreEngine::ExecuteWorkList(const LocationContext *L, unsigned Steps,
     WList->setBlockCounter(BCounterFactory.GetEmptyCounter());
 
     if (!InitState)
-      // Generate the root.
-      generateNode(StartLoc, SubEng.getInitialState(L), nullptr);
-    else
-      generateNode(StartLoc, InitState, nullptr);
+      InitState = SubEng.getInitialState(L);
+
+    bool IsNew;
+    ExplodedNode *Node = G.getNode(StartLoc, InitState, false, &IsNew);
+    assert (IsNew);
+    G.addRoot(Node);
+
+    NodeBuilderContext BuilderCtx(*this, StartLoc.getDst(), Node);
+    ExplodedNodeSet DstBegin;
+    SubEng.processBeginOfFunction(BuilderCtx, Node, DstBegin, StartLoc);
+
+    enqueue(DstBegin);
   }
 
   // Check if we have a steps limit
@@ -243,8 +251,7 @@ void CoreEngine::dispatchWorkItem(ExplodedNode* Pred, ProgramPoint Loc,
       break;
 
     case ProgramPoint::CallEnterKind: {
-      CallEnter CEnter = Loc.castAs<CallEnter>();
-      SubEng.processCallEnter(CEnter, Pred);
+      HandleCallEnter(Loc.castAs<CallEnter>(), Pred);
       break;
     }
 
@@ -456,6 +463,11 @@ void CoreEngine::HandleBlockExit(const CFGBlock * B, ExplodedNode *Pred) {
                Pred->State, Pred);
 }
 
+void CoreEngine::HandleCallEnter(const CallEnter &CE, ExplodedNode *Pred) {
+  NodeBuilderContext BuilderCtx(*this, CE.getEntry(), Pred);
+  SubEng.processCallEnter(BuilderCtx, CE, Pred);
+}
+
 void CoreEngine::HandleBranch(const Stmt *Cond, const Stmt *Term,
                                 const CFGBlock * B, ExplodedNode *Pred) {
   assert(B->succ_size() == 2);
diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
index 22b32f84141..0b669336a38 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -30,6 +30,7 @@
 #include "llvm/ADT/ImmutableList.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/SaveAndRestore.h"
 
 #ifndef NDEBUG
 #include "llvm/Support/GraphWriter.h"
@@ -1749,6 +1750,14 @@ static bool stackFrameDoesNotContainInitializedTemporaries(ExplodedNode &Pred) {
 }
 #endif
 
+void ExprEngine::processBeginOfFunction(NodeBuilderContext &BC,
+                                        ExplodedNode *Pred,
+                                        ExplodedNodeSet &Dst,
+                                        const BlockEdge &L) {
+  SaveAndRestore<const NodeBuilderContext *> NodeContextRAII(currBldrCtx, &BC);
+  getCheckerManager().runCheckersForBeginFunction(Dst, L, Pred, *this);
+}
+
 /// ProcessEndPath - Called by CoreEngine.  Used to generate end-of-path
 ///  nodes when the control reaches the end of a function.
 void ExprEngine::processEndOfFunction(NodeBuilderContext& BC,
diff --git a/clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp b/clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
index e667194198c..39d88bfda14 100644
--- a/clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
+++ b/clang/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
@@ -37,13 +37,12 @@ STATISTIC(NumInlinedCalls,
 STATISTIC(NumReachedInlineCountMax,
   "The # of times we reached inline count maximum");
 
-void ExprEngine::processCallEnter(CallEnter CE, ExplodedNode *Pred) {
+void ExprEngine::processCallEnter(NodeBuilderContext& BC, CallEnter CE,
+                                  ExplodedNode *Pred) {
   // Get the entry block in the CFG of the callee.
   const StackFrameContext *calleeCtx = CE.getCalleeContext();
   PrettyStackTraceLocationContext CrashInfo(calleeCtx);
-
-  const CFG *CalleeCFG = calleeCtx->getCFG();
-  const CFGBlock *Entry = &(CalleeCFG->getEntry());
+  const CFGBlock *Entry = CE.getEntry();
 
   // Validate the CFG.
   assert(Entry->empty());
@@ -57,12 +56,16 @@ void ExprEngine::processCallEnter(CallEnter CE, ExplodedNode *Pred) {
 
   ProgramStateRef state = Pred->getState();
 
-  // Construct a new node and add it to the worklist.
+  // Construct a new node, notify checkers that analysis of the function has
+  // begun, and add the resultant nodes to the worklist.
   bool isNew;
   ExplodedNode *Node = G.getNode(Loc, state, false, &isNew);
   Node->addPredecessor(Pred, G);
-  if (isNew)
-    Engine.getWorkList()->enqueue(Node);
+  if (isNew) {
+    ExplodedNodeSet DstBegin;
+    processBeginOfFunction(BC, Node, DstBegin, Loc);
+    Engine.enqueue(DstBegin);
+  }
 }
 
 // Find the last statement on the path to the exploded node and the