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//===-- STLAlgorithmModeling.cpp -----------------------------------*- C++ -*--//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Models STL algorithms.
//
//===----------------------------------------------------------------------===//
#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallDescription.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "Iterator.h"
using namespace clang;
using namespace ento;
using namespace iterator;
namespace {
class STLAlgorithmModeling : public Checker<eval::Call> {
bool evalFind(CheckerContext &C, const CallExpr *CE) const;
void Find(CheckerContext &C, const CallExpr *CE, unsigned paramNum) const;
using FnCheck = bool (STLAlgorithmModeling::*)(CheckerContext &,
const CallExpr *) const;
const CallDescriptionMap<FnCheck> Callbacks = {
{{{"std", "find"}, 3}, &STLAlgorithmModeling::evalFind},
{{{"std", "find"}, 4}, &STLAlgorithmModeling::evalFind},
{{{"std", "find_if"}, 3}, &STLAlgorithmModeling::evalFind},
{{{"std", "find_if"}, 4}, &STLAlgorithmModeling::evalFind},
{{{"std", "find_if_not"}, 3}, &STLAlgorithmModeling::evalFind},
{{{"std", "find_if_not"}, 4}, &STLAlgorithmModeling::evalFind},
{{{"std", "find_first_of"}, 4}, &STLAlgorithmModeling::evalFind},
{{{"std", "find_first_of"}, 5}, &STLAlgorithmModeling::evalFind},
{{{"std", "find_first_of"}, 6}, &STLAlgorithmModeling::evalFind},
{{{"std", "find_end"}, 4}, &STLAlgorithmModeling::evalFind},
{{{"std", "find_end"}, 5}, &STLAlgorithmModeling::evalFind},
{{{"std", "find_end"}, 6}, &STLAlgorithmModeling::evalFind},
{{{"std", "lower_bound"}, 3}, &STLAlgorithmModeling::evalFind},
{{{"std", "lower_bound"}, 4}, &STLAlgorithmModeling::evalFind},
{{{"std", "upper_bound"}, 3}, &STLAlgorithmModeling::evalFind},
{{{"std", "upper_bound"}, 4}, &STLAlgorithmModeling::evalFind},
{{{"std", "search"}, 3}, &STLAlgorithmModeling::evalFind},
{{{"std", "search"}, 4}, &STLAlgorithmModeling::evalFind},
{{{"std", "search"}, 5}, &STLAlgorithmModeling::evalFind},
{{{"std", "search"}, 6}, &STLAlgorithmModeling::evalFind},
{{{"std", "search_n"}, 4}, &STLAlgorithmModeling::evalFind},
{{{"std", "search_n"}, 5}, &STLAlgorithmModeling::evalFind},
{{{"std", "search_n"}, 6}, &STLAlgorithmModeling::evalFind},
};
public:
STLAlgorithmModeling() = default;
bool AggressiveStdFindModeling;
bool evalCall(const CallEvent &Call, CheckerContext &C) const;
}; //
bool STLAlgorithmModeling::evalCall(const CallEvent &Call,
CheckerContext &C) const {
const auto *CE = dyn_cast_or_null<CallExpr>(Call.getOriginExpr());
if (!CE)
return false;
const FnCheck *Handler = Callbacks.lookup(Call);
if (!Handler)
return false;
return (this->**Handler)(C, CE);
}
bool STLAlgorithmModeling::evalFind(CheckerContext &C,
const CallExpr *CE) const {
// std::find()-like functions either take their primary range in the first
// two parameters, or if the first parameter is "execution policy" then in
// the second and third. This means that the second parameter must always be
// an iterator.
if (!isIteratorType(CE->getArg(1)->getType()))
return false;
// If no "execution policy" parameter is used then the first argument is the
// beginning of the range.
if (isIteratorType(CE->getArg(0)->getType())) {
Find(C, CE, 0);
return true;
}
// If "execution policy" parameter is used then the second argument is the
// beginning of the range.
if (isIteratorType(CE->getArg(2)->getType())) {
Find(C, CE, 1);
return true;
}
return false;
}
void STLAlgorithmModeling::Find(CheckerContext &C, const CallExpr *CE,
unsigned paramNum) const {
auto State = C.getState();
auto &SVB = C.getSValBuilder();
const auto *LCtx = C.getLocationContext();
SVal RetVal = SVB.conjureSymbolVal(nullptr, CE, LCtx, C.blockCount());
SVal Param = State->getSVal(CE->getArg(paramNum), LCtx);
auto StateFound = State->BindExpr(CE, LCtx, RetVal);
// If we have an iterator position for the range-begin argument then we can
// assume that in case of successful search the position of the found element
// is not ahead of it.
// FIXME: Reverse iterators
const auto *Pos = getIteratorPosition(State, Param);
if (Pos) {
StateFound = createIteratorPosition(StateFound, RetVal, Pos->getContainer(),
CE, LCtx, C.blockCount());
const auto *NewPos = getIteratorPosition(StateFound, RetVal);
assert(NewPos && "Failed to create new iterator position.");
SVal GreaterOrEqual = SVB.evalBinOp(StateFound, BO_GE,
nonloc::SymbolVal(NewPos->getOffset()),
nonloc::SymbolVal(Pos->getOffset()),
SVB.getConditionType());
assert(isa<DefinedSVal>(GreaterOrEqual) &&
"Symbol comparison must be a `DefinedSVal`");
StateFound = StateFound->assume(GreaterOrEqual.castAs<DefinedSVal>(), true);
}
Param = State->getSVal(CE->getArg(paramNum + 1), LCtx);
// If we have an iterator position for the range-end argument then we can
// assume that in case of successful search the position of the found element
// is ahead of it.
// FIXME: Reverse iterators
Pos = getIteratorPosition(State, Param);
if (Pos) {
StateFound = createIteratorPosition(StateFound, RetVal, Pos->getContainer(),
CE, LCtx, C.blockCount());
const auto *NewPos = getIteratorPosition(StateFound, RetVal);
assert(NewPos && "Failed to create new iterator position.");
SVal Less = SVB.evalBinOp(StateFound, BO_LT,
nonloc::SymbolVal(NewPos->getOffset()),
nonloc::SymbolVal(Pos->getOffset()),
SVB.getConditionType());
assert(isa<DefinedSVal>(Less) &&
"Symbol comparison must be a `DefinedSVal`");
StateFound = StateFound->assume(Less.castAs<DefinedSVal>(), true);
}
C.addTransition(StateFound);
if (AggressiveStdFindModeling) {
auto StateNotFound = State->BindExpr(CE, LCtx, Param);
C.addTransition(StateNotFound);
}
}
} // namespace
void ento::registerSTLAlgorithmModeling(CheckerManager &Mgr) {
auto *Checker = Mgr.registerChecker<STLAlgorithmModeling>();
Checker->AggressiveStdFindModeling =
Mgr.getAnalyzerOptions().getCheckerBooleanOption(Checker,
"AggressiveStdFindModeling");
}
bool ento::shouldRegisterSTLAlgorithmModeling(const CheckerManager &mgr) {
return true;
}
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