This revision was automatically updated to reflect the committed changes.
Closed by commit rL334348: [analyzer] Add dangling internal buffer check. 
(authored by rkovacs, committed by ).
Herald added subscribers: llvm-commits, mikhail.ramalho.

Changed prior to commit:
  https://reviews.llvm.org/D47135?vs=148827&id=150623#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D47135

Files:
  cfe/trunk/include/clang/StaticAnalyzer/Checkers/Checkers.td
  cfe/trunk/lib/StaticAnalyzer/Checkers/AllocationState.h
  cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt
  cfe/trunk/lib/StaticAnalyzer/Checkers/DanglingInternalBufferChecker.cpp
  cfe/trunk/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
  cfe/trunk/test/Analysis/dangling-internal-buffer.cpp

Index: cfe/trunk/include/clang/StaticAnalyzer/Checkers/Checkers.td
===================================================================
--- cfe/trunk/include/clang/StaticAnalyzer/Checkers/Checkers.td
+++ cfe/trunk/include/clang/StaticAnalyzer/Checkers/Checkers.td
@@ -300,6 +300,11 @@
 
 let ParentPackage = CplusplusAlpha in {
 
+def DanglingInternalBufferChecker : Checker<"DanglingInternalBuffer">,
+  HelpText<"Check for internal raw pointers of C++ standard library containers "
+           "used after deallocation">,
+  DescFile<"DanglingInternalBufferChecker.cpp">;
+
 def DeleteWithNonVirtualDtorChecker : Checker<"DeleteWithNonVirtualDtor">,
   HelpText<"Reports destructions of polymorphic objects with a non-virtual "
            "destructor in their base class">,
Index: cfe/trunk/test/Analysis/dangling-internal-buffer.cpp
===================================================================
--- cfe/trunk/test/Analysis/dangling-internal-buffer.cpp
+++ cfe/trunk/test/Analysis/dangling-internal-buffer.cpp
@@ -0,0 +1,71 @@
+//RUN: %clang_analyze_cc1 -analyzer-checker=alpha.cplusplus.DanglingInternalBuffer %s -analyzer-output=text -verify
+
+namespace std {
+
+template< typename CharT >
+class basic_string {
+public:
+  ~basic_string();
+  const CharT *c_str();
+};
+
+typedef basic_string<char> string;
+typedef basic_string<wchar_t> wstring;
+typedef basic_string<char16_t> u16string;
+typedef basic_string<char32_t> u32string;
+
+} // end namespace std
+
+void consume(const char *) {}
+void consume(const wchar_t *) {}
+void consume(const char16_t *) {}
+void consume(const char32_t *) {}
+
+void deref_after_scope_char() {
+  const char *c;
+  {
+    std::string s;
+    c = s.c_str();
+  }
+  consume(c); // expected-warning {{Use of memory after it is freed}}
+  // expected-note@-1 {{Use of memory after it is freed}}
+}
+
+void deref_after_scope_wchar_t() {
+  const wchar_t *w;
+  {
+    std::wstring ws;
+    w = ws.c_str();
+  }
+  consume(w); // expected-warning {{Use of memory after it is freed}}
+  // expected-note@-1 {{Use of memory after it is freed}}
+}
+
+void deref_after_scope_char16_t() {
+  const char16_t *c16;
+  {
+    std::u16string s16;
+    c16 = s16.c_str();
+  }
+  consume(c16); // expected-warning {{Use of memory after it is freed}}
+  // expected-note@-1 {{Use of memory after it is freed}}
+}
+
+void deref_after_scope_char32_t() {
+  const char32_t *c32;
+  {
+    std::u32string s32;
+    c32 = s32.c_str();
+  }
+  consume(c32); // expected-warning {{Use of memory after it is freed}}
+  // expected-note@-1 {{Use of memory after it is freed}}
+}
+
+void deref_after_scope_ok() {
+  const char *c;
+  std::string s;
+  {
+    c = s.c_str();
+  }
+  consume(c); // no-warning
+}
Index: cfe/trunk/lib/StaticAnalyzer/Checkers/DanglingInternalBufferChecker.cpp
===================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/DanglingInternalBufferChecker.cpp
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/DanglingInternalBufferChecker.cpp
@@ -0,0 +1,88 @@
+//=== DanglingInternalBufferChecker.cpp ---------------------------*- C++ -*--//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a check that marks a raw pointer to a C++ standard library
+// container's inner buffer released when the object is destroyed. This
+// information can be used by MallocChecker to detect use-after-free problems.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClangSACheckers.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/CommonBugCategories.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "AllocationState.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+
+class DanglingInternalBufferChecker : public Checker<check::PostCall> {
+  CallDescription CStrFn;
+
+public:
+  DanglingInternalBufferChecker() : CStrFn("c_str") {}
+
+  /// Record the connection between the symbol returned by c_str() and the
+  /// corresponding string object region in the ProgramState. Mark the symbol
+  /// released if the string object is destroyed.
+  void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
+};
+
+} // end anonymous namespace
+
+// FIXME: c_str() may be called on a string object many times, so it should
+// have a list of symbols associated with it.
+REGISTER_MAP_WITH_PROGRAMSTATE(RawPtrMap, const MemRegion *, SymbolRef)
+
+void DanglingInternalBufferChecker::checkPostCall(const CallEvent &Call,
+                                                  CheckerContext &C) const {
+  const auto *ICall = dyn_cast<CXXInstanceCall>(&Call);
+  if (!ICall)
+    return;
+
+  SVal Obj = ICall->getCXXThisVal();
+  const auto *TypedR = dyn_cast_or_null<TypedValueRegion>(Obj.getAsRegion());
+  if (!TypedR)
+    return;
+
+  auto *TypeDecl = TypedR->getValueType()->getAsCXXRecordDecl();
+  if (TypeDecl->getName() != "basic_string")
+    return;
+
+  ProgramStateRef State = C.getState();
+
+  if (Call.isCalled(CStrFn)) {
+    SVal RawPtr = Call.getReturnValue();
+    if (!RawPtr.isUnknown()) {
+      State = State->set<RawPtrMap>(TypedR, RawPtr.getAsSymbol());
+      C.addTransition(State);
+    }
+    return;
+  }
+
+  if (isa<CXXDestructorCall>(ICall)) {
+    if (State->contains<RawPtrMap>(TypedR)) {
+      const SymbolRef *StrBufferPtr = State->get<RawPtrMap>(TypedR);
+      // FIXME: What if Origin is null?
+      const Expr *Origin = Call.getOriginExpr();
+      State = allocation_state::markReleased(State, *StrBufferPtr, Origin);
+      C.addTransition(State);
+      return;
+    }
+  }
+}
+
+void ento::registerDanglingInternalBufferChecker(CheckerManager &Mgr) {
+  registerNewDeleteChecker(Mgr);
+  Mgr.registerChecker<DanglingInternalBufferChecker>();
+}
Index: cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt
===================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/CMakeLists.txt
@@ -27,6 +27,7 @@
   CloneChecker.cpp
   ConversionChecker.cpp
   CXXSelfAssignmentChecker.cpp
+  DanglingInternalBufferChecker.cpp
   DeadStoresChecker.cpp
   DebugCheckers.cpp
   DeleteWithNonVirtualDtorChecker.cpp
Index: cfe/trunk/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
===================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
@@ -30,6 +30,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringExtras.h"
+#include "AllocationState.h"
 #include <climits>
 #include <utility>
 
@@ -45,7 +46,8 @@
   AF_CXXNew,
   AF_CXXNewArray,
   AF_IfNameIndex,
-  AF_Alloca
+  AF_Alloca,
+  AF_InternalBuffer
 };
 
 class RefState {
@@ -1467,6 +1469,7 @@
     case AF_CXXNew: os << "'new'"; return;
     case AF_CXXNewArray: os << "'new[]'"; return;
     case AF_IfNameIndex: os << "'if_nameindex()'"; return;
+    case AF_InternalBuffer: os << "container-specific allocator"; return;
     case AF_Alloca:
     case AF_None: llvm_unreachable("not a deallocation expression");
   }
@@ -1479,6 +1482,7 @@
     case AF_CXXNew: os << "'delete'"; return;
     case AF_CXXNewArray: os << "'delete[]'"; return;
     case AF_IfNameIndex: os << "'if_freenameindex()'"; return;
+    case AF_InternalBuffer: os << "container-specific deallocator"; return;
     case AF_Alloca:
     case AF_None: llvm_unreachable("suspicious argument");
   }
@@ -1653,7 +1657,9 @@
     return Optional<MallocChecker::CheckKind>();
   }
   case AF_CXXNew:
-  case AF_CXXNewArray: {
+  case AF_CXXNewArray:
+  // FIXME: Add new CheckKind for AF_InternalBuffer.
+  case AF_InternalBuffer: {
     if (IsALeakCheck) {
       if (ChecksEnabled[CK_NewDeleteLeaksChecker])
         return CK_NewDeleteLeaksChecker;
@@ -2991,6 +2997,20 @@
   }
 }
 
+namespace clang {
+namespace ento {
+namespace allocation_state {
+
+ProgramStateRef
+markReleased(ProgramStateRef State, SymbolRef Sym, const Expr *Origin) {
+  AllocationFamily Family = AF_InternalBuffer;
+  return State->set<RegionState>(Sym, RefState::getReleased(Family, Origin));
+}
+
+} // end namespace allocation_state
+} // end namespace ento
+} // end namespace clang
+
 void ento::registerNewDeleteLeaksChecker(CheckerManager &mgr) {
   registerCStringCheckerBasic(mgr);
   MallocChecker *checker = mgr.registerChecker<MallocChecker>();
Index: cfe/trunk/lib/StaticAnalyzer/Checkers/AllocationState.h
===================================================================
--- cfe/trunk/lib/StaticAnalyzer/Checkers/AllocationState.h
+++ cfe/trunk/lib/StaticAnalyzer/Checkers/AllocationState.h
@@ -0,0 +1,28 @@
+//===--- AllocationState.h ------------------------------------- *- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_LIB_STATICANALYZER_CHECKERS_ALLOCATIONSTATE_H
+#define LLVM_CLANG_LIB_STATICANALYZER_CHECKERS_ALLOCATIONSTATE_H
+
+#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
+
+namespace clang {
+namespace ento {
+
+namespace allocation_state {
+
+ProgramStateRef markReleased(ProgramStateRef State, SymbolRef Sym,
+                             const Expr *Origin);
+
+} // end namespace allocation_state
+
+} // end namespace ento
+} // end namespace clang
+
+#endif
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