[PATCH] D103750: [analyzer] Handle std::make_unique for SmartPtrModeling

[Deep Majumder via Phabricator via cfe-commits]

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This patch models the std::make_unique method.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D103750

Files:
  clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp


Index: clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
+++ clang/lib/StaticAnalyzer/Checkers/SmartPtrModeling.cpp
@@ -40,6 +40,7 @@
                      check::LiveSymbols> {
 
   bool isBoolConversionMethod(const CallEvent &Call) const;
+  bool isStdMakeUniqueCall(const CallEvent &Call) const;
 
 public:
   // Whether the checker should model for null dereferences of smart pointers.
@@ -68,6 +69,7 @@
   bool updateMovedSmartPointers(CheckerContext &C, const MemRegion *ThisRegion,
                                 const MemRegion *OtherSmartPtrRegion) const;
   void handleBoolConversion(const CallEvent &Call, CheckerContext &C) const;
+  void handleMakeUnique(const CallEvent &Call, CheckerContext &C) const;
 
   using SmartPtrMethodHandlerFn =
       void (SmartPtrModeling::*)(const CallEvent &Call, CheckerContext &) const;
@@ -175,8 +177,31 @@
   return CD && CD->getConversionType()->isBooleanType();
 }
 
+bool SmartPtrModeling::isStdMakeUniqueCall(const CallEvent &Call) const {
+  if (Call.getKind() != CallEventKind::CE_Function)
+    return false;
+  const auto *D = Call.getDecl();
+  if (!D)
+    return false;
+  const auto *FTD = llvm::dyn_cast<FunctionDecl>(D);
+  if (!FTD)
+    return false;
+  if (FTD->getDeclName().isIdentifier()) {
+    StringRef Name = FTD->getName();
+    if (Name == "make_unique")
+      return true;
+  }
+  return false;
+}
+
 bool SmartPtrModeling::evalCall(const CallEvent &Call,
                                 CheckerContext &C) const {
+
+  if (isStdMakeUniqueCall(Call)) {
+    handleMakeUnique(Call, C);
+    return true;
+  }
+
   ProgramStateRef State = C.getState();
   if (!smartptr::isStdSmartPtrCall(Call))
     return false;
@@ -272,6 +297,21 @@
   return C.isDifferent();
 }
 
+void SmartPtrModeling::handleMakeUnique(const CallEvent &Call,
+                                        CheckerContext &C) const {
+  const auto *OriginExpr = Call.getOriginExpr();
+  const auto *LocCtx = C.getLocationContext();
+  auto ExprVal = C.getSValBuilder().conjureSymbolVal(
+      OriginExpr, LocCtx, Call.getResultType(), C.blockCount());
+  ProgramStateRef State = C.getState();
+  State = State->BindExpr(OriginExpr, LocCtx, ExprVal);
+
+  // With make unique it is not possible to make a null smart pointer.
+  // So we can set the SVal for Call.getOriginExpr() to be non-null
+  State = State->assume(ExprVal, true);
+  C.addTransition(State);
+}
+
 void SmartPtrModeling::checkDeadSymbols(SymbolReaper &SymReaper,
                                         CheckerContext &C) const {
   ProgramStateRef State = C.getState();


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