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//=== UndefResultChecker.cpp ------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This defines UndefResultChecker, a builtin check in ExprEngine that
// performs checks for undefined results of non-assignment binary operators.
//
//===----------------------------------------------------------------------===//
#include "ClangSACheckers.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/raw_ostream.h"
using namespace clang;
using namespace ento;
namespace {
class UndefResultChecker
: public Checker< check::PostStmt<BinaryOperator> > {
mutable std::unique_ptr<BugType> BT;
public:
void checkPostStmt(const BinaryOperator *B, CheckerContext &C) const;
};
} // end anonymous namespace
void UndefResultChecker::checkPostStmt(const BinaryOperator *B,
CheckerContext &C) const {
ProgramStateRef state = C.getState();
const LocationContext *LCtx = C.getLocationContext();
if (state->getSVal(B, LCtx).isUndef()) {
// Do not report assignments of uninitialized values inside swap functions.
// This should allow to swap partially uninitialized structs
// (radar://14129997)
if (const FunctionDecl *EnclosingFunctionDecl =
dyn_cast<FunctionDecl>(C.getStackFrame()->getDecl()))
if (C.getCalleeName(EnclosingFunctionDecl) == "swap")
return;
// Generate an error node.
ExplodedNode *N = C.generateSink();
if (!N)
return;
if (!BT)
BT.reset(
new BuiltinBug(this, "Result of operation is garbage or undefined"));
SmallString<256> sbuf;
llvm::raw_svector_ostream OS(sbuf);
const Expr *Ex = nullptr;
bool isLeft = true;
if (state->getSVal(B->getLHS(), LCtx).isUndef()) {
Ex = B->getLHS()->IgnoreParenCasts();
isLeft = true;
}
else if (state->getSVal(B->getRHS(), LCtx).isUndef()) {
Ex = B->getRHS()->IgnoreParenCasts();
isLeft = false;
}
if (Ex) {
OS << "The " << (isLeft ? "left" : "right")
<< " operand of '"
<< BinaryOperator::getOpcodeStr(B->getOpcode())
<< "' is a garbage value";
}
else {
// Neither operand was undefined, but the result is undefined.
OS << "The result of the '"
<< BinaryOperator::getOpcodeStr(B->getOpcode())
<< "' expression is undefined";
}
BugReport *report = new BugReport(*BT, OS.str(), N);
if (Ex) {
report->addRange(Ex->getSourceRange());
bugreporter::trackNullOrUndefValue(N, Ex, *report);
}
else
bugreporter::trackNullOrUndefValue(N, B, *report);
C.emitReport(report);
}
}
void ento::registerUndefResultChecker(CheckerManager &mgr) {
mgr.registerChecker<UndefResultChecker>();
}
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