llvm-project/clang/lib/Analysis/ReturnStackAddressChecker.cpp
Ted Kremenek f57351570e Clean up the Checker API a little more, resolving some hidden bugs
along the way.  Important changes:

1) To generate a sink node, use GenerateSink(); GenerateNode() is for
generating regular transitions.  This makes the API clearer and also
allows us to use the 'bool' option to GenerateNode() for a different
purpose.

2) GenerateNode() now automatically adds the generated node to the
destination ExplodedNodeSet (autotransition) unless the client
specifies otherwise with a bool flag.  Several checkers did not call
'addTransition()' after calling 'GenerateNode()', causing the
simulation path to be prematurely culled when a non-fail stop bug was
encountered.

3) Add variants of GenerateNode()/GenerateSink() that take neither a
Stmt* or a GRState*; most callers of GenerateNode() just pass in the
same Stmt* as provided when the CheckerContext object is created; we
can just use that the majority of the time.  This cleanup also allows
us to potentially coelesce the APIs for evaluating branches and
end-of-paths (which currently directly use builders).

4) addTransition() no longer needs to be called except for a few
cases.  We now have a variant of addTransition() that takes a
GRState*; this allows one to propagate the updated state without
caring about generating a new node explicitly.  This nicely cleaned up
a bunch of cases that called autoTransition() with a bunch of
conditional logic surround the call (that common logic has now been
swallowed up by addTransition() itself).

llvm-svn: 89707
2009-11-23 22:22:01 +00:00

98 lines
3.0 KiB
C++

//== ReturnStackAddressChecker.cpp ------------------------------*- C++ -*--==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines ReturnStackAddressChecker, which is a path-sensitive
// check which looks for the addresses of stack variables being returned to
// callers.
//
//===----------------------------------------------------------------------===//
#include "GRExprEngineInternalChecks.h"
#include "clang/Analysis/PathSensitive/GRExprEngine.h"
#include "clang/Analysis/PathSensitive/BugReporter.h"
#include "clang/Analysis/PathSensitive/CheckerVisitor.h"
#include "llvm/ADT/SmallString.h"
using namespace clang;
namespace {
class VISIBILITY_HIDDEN ReturnStackAddressChecker :
public CheckerVisitor<ReturnStackAddressChecker> {
BuiltinBug *BT;
public:
ReturnStackAddressChecker() : BT(0) {}
static void *getTag();
void PreVisitReturnStmt(CheckerContext &C, const ReturnStmt *RS);
};
}
void clang::RegisterReturnStackAddressChecker(GRExprEngine &Eng) {
Eng.registerCheck(new ReturnStackAddressChecker());
}
void *ReturnStackAddressChecker::getTag() {
static int x = 0; return &x;
}
void ReturnStackAddressChecker::PreVisitReturnStmt(CheckerContext &C,
const ReturnStmt *RS) {
const Expr *RetE = RS->getRetValue();
if (!RetE)
return;
SVal V = C.getState()->getSVal(RetE);
const MemRegion *R = V.getAsRegion();
if (!R || !R->hasStackStorage())
return;
ExplodedNode *N = C.GenerateSink();
if (!N)
return;
if (!BT)
BT = new BuiltinBug("Return of address to stack-allocated memory");
// Generate a report for this bug.
llvm::SmallString<100> buf;
llvm::raw_svector_ostream os(buf);
SourceRange range;
// Check if the region is a compound literal.
if (const CompoundLiteralRegion* CR = dyn_cast<CompoundLiteralRegion>(R)) {
const CompoundLiteralExpr* CL = CR->getLiteralExpr();
os << "Address of stack memory associated with a compound literal "
"declared on line "
<< C.getSourceManager().getInstantiationLineNumber(CL->getLocStart())
<< " returned to caller";
range = CL->getSourceRange();
}
else if (const AllocaRegion* AR = dyn_cast<AllocaRegion>(R)) {
const Expr* ARE = AR->getExpr();
SourceLocation L = ARE->getLocStart();
range = ARE->getSourceRange();
os << "Address of stack memory allocated by call to alloca() on line "
<< C.getSourceManager().getInstantiationLineNumber(L)
<< " returned to caller";
}
else {
os << "Address of stack memory associated with local variable '"
<< R->getString() << "' returned.";
}
RangedBugReport *report = new RangedBugReport(*BT, os.str(), N);
report->addRange(RS->getSourceRange());
if (range.isValid())
report->addRange(range);
C.EmitReport(report);
}