blob: 05865c294cb700a4dfcf37a722f924189117631b [file] [log] [blame]
//===--- LoopWidening.cpp - Widen loops -------------------------*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
/// This file contains functions which are used to widen loops. A loop may be
/// widened to approximate the exit state(s), without analyzing every
/// iteration. The widening is done by invalidating anything which might be
/// modified by the body of the loop.
#include "clang/StaticAnalyzer/Core/PathSensitive/LoopWidening.h"
using namespace clang;
using namespace ento;
/// Return the loops condition Stmt or NULL if LoopStmt is not a loop
static const Expr *getLoopCondition(const Stmt *LoopStmt) {
switch (LoopStmt->getStmtClass()) {
return nullptr;
case Stmt::ForStmtClass:
return cast<ForStmt>(LoopStmt)->getCond();
case Stmt::WhileStmtClass:
return cast<WhileStmt>(LoopStmt)->getCond();
case Stmt::DoStmtClass:
return cast<DoStmt>(LoopStmt)->getCond();
namespace clang {
namespace ento {
ProgramStateRef getWidenedLoopState(ProgramStateRef PrevState,
const LocationContext *LCtx,
unsigned BlockCount, const Stmt *LoopStmt) {
assert(isa<ForStmt>(LoopStmt) || isa<WhileStmt>(LoopStmt) ||
// Invalidate values in the current state.
// TODO Make this more conservative by only invalidating values that might
// be modified by the body of the loop.
// TODO Nested loops are currently widened as a result of the invalidation
// being so inprecise. When the invalidation is improved, the handling
// of nested loops will also need to be improved.
const StackFrameContext *STC = LCtx->getCurrentStackFrame();
MemRegionManager &MRMgr = PrevState->getStateManager().getRegionManager();
const MemRegion *Regions[] = {MRMgr.getStackLocalsRegion(STC),
RegionAndSymbolInvalidationTraits ITraits;
for (auto *Region : Regions) {
return PrevState->invalidateRegions(Regions, getLoopCondition(LoopStmt),
BlockCount, LCtx, true, nullptr, nullptr,
} // end namespace ento
} // end namespace clang