=?utf-8?q?Donát?= Nagy <donat.n...@ericsson.com>,
=?utf-8?q?Donát?= Nagy <donat.n...@ericsson.com>,
=?utf-8?q?Donát?= Nagy <donat.n...@ericsson.com>,
=?utf-8?q?Donát?= Nagy <donat.n...@ericsson.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/91...@github.com>
================
@@ -136,53 +100,49 @@ void ErrnoModeling::checkBeginFunction(CheckerContext &C)
const {
ASTContext &ACtx = C.getASTContext();
ProgramStateRef State = C.getState();
- if (const auto *ErrnoVar = dyn_cast_or_null<VarDecl>(ErrnoDecl)) {
- // There is an external 'errno' variable.
- // Use its memory region.
- // The memory region for an 'errno'-like variable is allocated in system
- // space by MemRegionManager.
- const MemRegion *ErrnoR =
- State->getRegion(ErrnoVar, C.getLocationContext());
+ const MemRegion *ErrnoR;
+
+ if (ErrnoDecl) {
+ // There is an external 'errno' variable, so we can simply use the memory
+ // region that's associated with it.
+ ErrnoR = State->getRegion(ErrnoDecl, C.getLocationContext());
assert(ErrnoR && "Memory region should exist for the 'errno' variable.");
- State = State->set<ErrnoRegion>(ErrnoR);
- State =
- errno_modeling::setErrnoValue(State, C, 0, errno_modeling::Irrelevant);
- C.addTransition(State);
- } else if (ErrnoDecl) {
- assert(isa<FunctionDecl>(ErrnoDecl) && "Invalid errno location function.");
- // There is a function that returns the location of 'errno'.
- // We must create a memory region for it in system space.
- // Currently a symbolic region is used with an artifical symbol.
- // FIXME: It is better to have a custom (new) kind of MemRegion for such
- // cases.
+ } else {
+ // There is no 'errno' variable, so create a new symbolic memory region
+ // that can be used to model the return value of the "get the location of
+ // errno" internal functions.
+ // NOTE: this `SVal` is created even if errno is not defined or used.
SValBuilder &SVB = C.getSValBuilder();
MemRegionManager &RMgr = C.getStateManager().getRegionManager();
const MemSpaceRegion *GlobalSystemSpace =
RMgr.getGlobalsRegion(MemRegion::GlobalSystemSpaceRegionKind);
// Create an artifical symbol for the region.
- // It is not possible to associate a statement or expression in this case.
+ // Note that it is not possible to associate a statement or expression in
+ // this case and the `symbolTag` (opaque pointer tag) is just the address
+ // of the data member `ErrnoDecl` of the singleton `ErrnoModeling` checker
+ // object.
const SymbolConjured *Sym = SVB.conjureSymbol(
nullptr, C.getLocationContext(),
ACtx.getLValueReferenceType(ACtx.IntTy), C.blockCount(), &ErrnoDecl);
// The symbolic region is untyped, create a typed sub-region in it.
// The ElementRegion is used to make the errno region a typed region.
- const MemRegion *ErrnoR = RMgr.getElementRegion(
+ ErrnoR = RMgr.getElementRegion(
ACtx.IntTy, SVB.makeZeroArrayIndex(),
RMgr.getSymbolicRegion(Sym, GlobalSystemSpace), C.getASTContext());
- State = State->set<ErrnoRegion>(ErrnoR);
- State =
- errno_modeling::setErrnoValue(State, C, 0, errno_modeling::Irrelevant);
- C.addTransition(State);
}
+ State = State->set<ErrnoRegion>(ErrnoR);
----------------
steakhal wrote:
```suggestion
assert(ErrnoR);
State = State->set<ErrnoRegion>(ErrnoR);
```
https://github.com/llvm/llvm-project/pull/91531
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