Reimplement out-of-bound array access checker with the new checker interface.

Now only one test case is XFAIL'ed.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@86834 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/ArrayBoundChecker.cpp

+//== ArrayBoundChecker.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 ArrayBoundChecker, which is a path-sensitive check
+// which looks for an out-of-bound array element access.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GRExprEngineInternalChecks.h"
+#include "clang/Analysis/PathSensitive/GRExprEngine.h"
+#include "clang/Analysis/PathSensitive/BugReporter.h"
+#include "clang/Analysis/PathSensitive/CheckerVisitor.h"
+
+using namespace clang;
+
+namespace {
+class VISIBILITY_HIDDEN ArrayBoundChecker : 
+    public CheckerVisitor<ArrayBoundChecker> {      
+  BuiltinBug *BT;
+public:
+    ArrayBoundChecker() : BT(0) {}
+    static void *getTag();
+    void VisitLocation(CheckerContext &C, const Stmt *S, SVal l);
+};
+}
+
+void clang::RegisterArrayBoundChecker(GRExprEngine &Eng) {
+  Eng.registerCheck(new ArrayBoundChecker());
+}
+
+void *ArrayBoundChecker::getTag() {
+  static int x = 0; return &x;
+}
+
+void ArrayBoundChecker::VisitLocation(CheckerContext &C, const Stmt *S, SVal l){
+  // Check for out of bound array element access.
+  const MemRegion *R = l.getAsRegion();
+  if (!R)
+    return;
+
+  R = R->StripCasts();
+
+  const ElementRegion *ER = dyn_cast<ElementRegion>(R);
+  if (!ER)
+    return;
+
+  // Get the index of the accessed element.
+  DefinedOrUnknownSVal &Idx = cast<DefinedOrUnknownSVal>(ER->getIndex());
+
+  const GRState *state = C.getState();
+
+  // Get the size of the array.
+  SVal NumVal = C.getStoreManager().getSizeInElements(state,
+                                                      ER->getSuperRegion());
+  DefinedOrUnknownSVal &NumElements = cast<DefinedOrUnknownSVal>(NumVal);
+
+  const GRState *StInBound = state->AssumeInBound(Idx, NumElements, true);
+  const GRState *StOutBound = state->AssumeInBound(Idx, NumElements, false);
+  if (StOutBound && !StInBound) {
+    ExplodedNode *N = C.GenerateNode(S, StOutBound, true);
+
+    if (!N)
+      return;
+  
+    if (!BT)
+      BT = new BuiltinBug("Out-of-bound array access",
+                       "Access out-of-bound array element (buffer overflow)");
+
+    // FIXME: It would be nice to eventually make this diagnostic more clear,
+    // e.g., by referencing the original declaration or by saying *why* this
+    // reference is outside the range.
+
+    // Generate a report for this bug.
+    RangedBugReport *report = 
+      new RangedBugReport(*BT, BT->getDescription().c_str(), N);
+
+    report->addRange(S->getSourceRange());
+
+    C.EmitReport(report);
+  }
+}

lib/Analysis/CMakeLists.txt

@@ -2,6 +2,7 @@ set(LLVM_NO_RTTI 1)
 
 add_clang_library(clangAnalysis
   AnalysisContext.cpp
+  ArrayBoundChecker.cpp
   AttrNonNullChecker.cpp
   BadCallChecker.cpp
   BasicConstraintManager.cpp

lib/Analysis/GRExprEngineInternalChecks.cpp

@@ -414,4 +414,5 @@ void GRExprEngine::RegisterInternalChecks() {
   RegisterReturnPointerRangeChecker(*this);
 
   RegisterCastToStructChecker(*this);
+  RegisterArrayBoundChecker(*this);
 }

lib/Analysis/GRExprEngineInternalChecks.h

@@ -32,6 +32,7 @@ void RegisterPointerArithChecker(GRExprEngine &Eng);
 void RegisterFixedAddressChecker(GRExprEngine &Eng);
 void RegisterCastToStructChecker(GRExprEngine &Eng);
 void RegisterUndefinedArgChecker(GRExprEngine &Eng);
+void RegisterArrayBoundChecker(GRExprEngine &Eng);
 
 } // end clang namespace
 #endif

test/Analysis/no-outofbounds.c

 // RUN: clang-cc -checker-cfref -analyze -analyzer-store=basic -verify %s
 // RUN: clang-cc -checker-cfref -analyze -analyzer-store=region -verify %s
+// XFAIL: *
 
 //===----------------------------------------------------------------------===//
 // This file tests cases where we should not flag out-of-bounds warnings.

test/Analysis/outofbound.c

 // RUN: clang-cc -analyze -checker-cfref -analyzer-store=region -verify %s
-// XFAIL: *
 
 char f1() {
   char* s = "abcd";
   char c = s[4]; // no-warning
-  return s[5] + c; // expected-warning{{Load or store into an out-of-bound memory position.}}
+  return s[5] + c; // expected-warning{{Access out-of-bound array element (buffer overflow)}}
 }

test/Analysis/rdar-6541136-region.c

@@ -13,10 +13,10 @@ void foo( void )
   struct load_wine *cmd = (void*) &wonky[1];
   cmd = cmd;
   char *p = (void*) &wonky[1];
-  *p = 1;  // no-warning
+  //*p = 1;  // this is also an out-of-bound access.
   kernel_tea_cheese_t *q = &wonky[1];
   // This test case tests both the RegionStore logic (doesn't crash) and
   // the out-of-bounds checking.  We don't expect the warning for now since
   // out-of-bound checking is temporarily disabled.
-  kernel_tea_cheese_t r = *q; // eventually-warning{{out-of-bound memory position}}
+  kernel_tea_cheese_t r = *q; // expected-warning{{Access out-of-bound array element (buffer overflow)}}
 }