forked from OSchip/llvm-project
98 lines
3.1 KiB
C++
98 lines
3.1 KiB
C++
//=== VLASizeChecker.cpp - Undefined dereference checker --------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This defines VLASizeChecker, a builtin check in GRExprEngine that
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// performs checks for declaration of VLA of undefined or zero size.
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//
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//===----------------------------------------------------------------------===//
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#include "GRExprEngineInternalChecks.h"
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#include "clang/Analysis/PathSensitive/CheckerVisitor.h"
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#include "clang/Analysis/PathSensitive/GRExprEngine.h"
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#include "clang/Analysis/PathSensitive/BugReporter.h"
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using namespace clang;
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namespace {
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class VISIBILITY_HIDDEN VLASizeChecker : public CheckerVisitor<VLASizeChecker> {
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BugType *BT_zero;
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BugType *BT_undef;
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public:
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VLASizeChecker() : BT_zero(0), BT_undef(0) {}
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static void *getTag() { static int tag = 0; return &tag; }
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void PreVisitDeclStmt(CheckerContext &C, const DeclStmt *DS);
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};
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} // end anonymous namespace
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void clang::RegisterVLASizeChecker(GRExprEngine &Eng) {
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Eng.registerCheck(new VLASizeChecker());
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}
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void VLASizeChecker::PreVisitDeclStmt(CheckerContext &C, const DeclStmt *DS) {
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if (!DS->isSingleDecl())
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return;
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const VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
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if (!VD)
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return;
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const VariableArrayType *VLA
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= C.getASTContext().getAsVariableArrayType(VD->getType());
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if (!VLA)
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return;
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// FIXME: Handle multi-dimensional VLAs.
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const Expr* SE = VLA->getSizeExpr();
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const GRState *state = C.getState();
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SVal sizeV = state->getSVal(SE);
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if (sizeV.isUndef()) {
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// Generate an error node.
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ExplodedNode *N = C.GenerateNode(DS, true);
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if (!N)
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return;
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if (!BT_undef)
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BT_undef = new BuiltinBug("Declared variable-length array (VLA) uses a "
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"garbage value as its size");
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EnhancedBugReport *report =
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new EnhancedBugReport(*BT_undef, BT_undef->getName(), N);
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report->addRange(SE->getSourceRange());
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report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, SE);
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C.EmitReport(report);
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return;
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}
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// Check if the size is zero.
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DefinedOrUnknownSVal sizeD = cast<DefinedOrUnknownSVal>(sizeV);
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const GRState *stateNotZero, *stateZero;
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llvm::tie(stateNotZero, stateZero) = state->Assume(sizeD);
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if (stateZero && !stateNotZero) {
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ExplodedNode* N = C.GenerateNode(DS, stateZero, true);
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if (!BT_zero)
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BT_zero = new BuiltinBug("Declared variable-length array (VLA) has zero "
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"size");
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EnhancedBugReport *report =
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new EnhancedBugReport(*BT_zero, BT_zero->getName(), N);
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report->addRange(SE->getSourceRange());
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report->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, SE);
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C.EmitReport(report);
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return;
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}
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// From this point on, assume that the size is not zero.
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if (state != stateNotZero)
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C.addTransition(C.GenerateNode(DS, stateNotZero));
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}
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