Chris Lattner has strong opinions about directory
layout. :)
Rename the 'EntoSA' directories to 'StaticAnalyzer'.
Internally we will still use the 'ento' namespace
for the analyzer engine (unless there are further
sabre rattlings...).
llvm-svn: 122514
diff --git a/clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
new file mode 100644
index 0000000..e24521a
--- /dev/null
+++ b/clang/lib/StaticAnalyzer/Checkers/VLASizeChecker.cpp
@@ -0,0 +1,138 @@
+//=== VLASizeChecker.cpp - Undefined dereference checker --------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This defines VLASizeChecker, a builtin check in ExprEngine that
+// performs checks for declaration of VLA of undefined or zero size.
+// In addition, VLASizeChecker is responsible for defining the extent
+// of the MemRegion that represents a VLA.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ExprEngineInternalChecks.h"
+#include "clang/AST/CharUnits.h"
+#include "clang/StaticAnalyzer/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/PathSensitive/CheckerVisitor.h"
+#include "clang/StaticAnalyzer/PathSensitive/ExprEngine.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+class VLASizeChecker : public CheckerVisitor<VLASizeChecker> {
+ BugType *BT_zero;
+ BugType *BT_undef;
+
+public:
+ VLASizeChecker() : BT_zero(0), BT_undef(0) {}
+ static void *getTag() { static int tag = 0; return &tag; }
+ void PreVisitDeclStmt(CheckerContext &C, const DeclStmt *DS);
+};
+} // end anonymous namespace
+
+void ento::RegisterVLASizeChecker(ExprEngine &Eng) {
+ Eng.registerCheck(new VLASizeChecker());
+}
+
+void VLASizeChecker::PreVisitDeclStmt(CheckerContext &C, const DeclStmt *DS) {
+ if (!DS->isSingleDecl())
+ return;
+
+ const VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
+ if (!VD)
+ return;
+
+ ASTContext &Ctx = C.getASTContext();
+ const VariableArrayType *VLA = Ctx.getAsVariableArrayType(VD->getType());
+ if (!VLA)
+ return;
+
+ // FIXME: Handle multi-dimensional VLAs.
+ const Expr* SE = VLA->getSizeExpr();
+ const GRState *state = C.getState();
+ SVal sizeV = state->getSVal(SE);
+
+ if (sizeV.isUndef()) {
+ // Generate an error node.
+ ExplodedNode *N = C.generateSink();
+ if (!N)
+ return;
+
+ if (!BT_undef)
+ BT_undef = new BuiltinBug("Declared variable-length array (VLA) uses a "
+ "garbage value as its size");
+
+ EnhancedBugReport *report =
+ new EnhancedBugReport(*BT_undef, BT_undef->getName(), N);
+ report->addRange(SE->getSourceRange());
+ report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, SE);
+ C.EmitReport(report);
+ return;
+ }
+
+ // See if the size value is known. It can't be undefined because we would have
+ // warned about that already.
+ if (sizeV.isUnknown())
+ return;
+
+ // Check if the size is zero.
+ DefinedSVal sizeD = cast<DefinedSVal>(sizeV);
+
+ const GRState *stateNotZero, *stateZero;
+ llvm::tie(stateNotZero, stateZero) = state->assume(sizeD);
+
+ if (stateZero && !stateNotZero) {
+ ExplodedNode* N = C.generateSink(stateZero);
+ if (!BT_zero)
+ BT_zero = new BuiltinBug("Declared variable-length array (VLA) has zero "
+ "size");
+
+ EnhancedBugReport *report =
+ new EnhancedBugReport(*BT_zero, BT_zero->getName(), N);
+ report->addRange(SE->getSourceRange());
+ report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, SE);
+ C.EmitReport(report);
+ return;
+ }
+
+ // From this point on, assume that the size is not zero.
+ state = stateNotZero;
+
+ // VLASizeChecker is responsible for defining the extent of the array being
+ // declared. We do this by multiplying the array length by the element size,
+ // then matching that with the array region's extent symbol.
+
+ // Convert the array length to size_t.
+ SValBuilder &svalBuilder = C.getSValBuilder();
+ QualType SizeTy = Ctx.getSizeType();
+ NonLoc ArrayLength = cast<NonLoc>(svalBuilder.evalCast(sizeD, SizeTy,
+ SE->getType()));
+
+ // Get the element size.
+ CharUnits EleSize = Ctx.getTypeSizeInChars(VLA->getElementType());
+ SVal EleSizeVal = svalBuilder.makeIntVal(EleSize.getQuantity(), SizeTy);
+
+ // Multiply the array length by the element size.
+ SVal ArraySizeVal = svalBuilder.evalBinOpNN(state, BO_Mul, ArrayLength,
+ cast<NonLoc>(EleSizeVal), SizeTy);
+
+ // Finally, assume that the array's extent matches the given size.
+ const LocationContext *LC = C.getPredecessor()->getLocationContext();
+ DefinedOrUnknownSVal Extent =
+ state->getRegion(VD, LC)->getExtent(svalBuilder);
+ DefinedOrUnknownSVal ArraySize = cast<DefinedOrUnknownSVal>(ArraySizeVal);
+ DefinedOrUnknownSVal sizeIsKnown =
+ svalBuilder.evalEQ(state, Extent, ArraySize);
+ state = state->assume(sizeIsKnown, true);
+
+ // Assume should not fail at this point.
+ assert(state);
+
+ // Remember our assumptions!
+ C.addTransition(state);
+}