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When analyzing a C++ method (without a specific caller), assume 'this' is non-null. Fixes <rdar://problem/10508787>. 

llvm-svn: 145575
This commit is contained in:
Ted Kremenek 2011-12-01 05:29:42 +00:00
parent f37bd2f2f1
commit 24fc93a940
2 changed files with 47 additions and 16 deletions
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49
clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
View File

@ -83,13 +83,13 @@ ExprEngine::~ExprEngine() {
const ProgramState *ExprEngine::getInitialState(const LocationContext *InitLoc) {
const ProgramState *state = StateMgr.getInitialState(InitLoc);
const Decl *D = InitLoc->getDecl();
// Preconditions.
// FIXME: It would be nice if we had a more general mechanism to add
// such preconditions. Some day.
do {
const Decl *D = InitLoc->getDecl();
if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
// Precondition: the first argument of 'main' is an integer guaranteed
// to be > 0.
@ -119,25 +119,42 @@ const ProgramState *ExprEngine::getInitialState(const LocationContext *InitLoc)
if (const ProgramState *newState = state->assume(*Constraint, true))
state = newState;
break;
}
break;
}
while (0);
if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
// Precondition: 'self' is always non-null upon entry to an Objective-C
// method.
const ImplicitParamDecl *SelfD = MD->getSelfDecl();
const MemRegion *R = state->getRegion(SelfD, InitLoc);
SVal V = state->getSVal(loc::MemRegionVal(R));
if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) {
// Precondition: 'self' is always non-null upon entry to an Objective-C
// method.
const ImplicitParamDecl *SelfD = MD->getSelfDecl();
const MemRegion *R = state->getRegion(SelfD, InitLoc);
SVal V = state->getSVal(loc::MemRegionVal(R));
if (const Loc *LV = dyn_cast<Loc>(&V)) {
// Assume that the pointer value in 'self' is non-null.
state = state->assume(*LV, true);
assert(state && "'self' cannot be null");
if (const Loc *LV = dyn_cast<Loc>(&V)) {
// Assume that the pointer value in 'self' is non-null.
state = state->assume(*LV, true);
assert(state && "'self' cannot be null");
}
}
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(D)) {
if (!MD->isStatic()) {
// Precondition: 'this' is always non-null upon entry to the
// top-level function. This is our starting assumption for
// analyzing an "open" program.
const StackFrameContext *SFC = InitLoc->getCurrentStackFrame();
if (SFC->getParent() == 0) {
loc::MemRegionVal L(getCXXThisRegion(MD, SFC));
SVal V = state->getSVal(L);
if (const Loc *LV = dyn_cast<Loc>(&V)) {
state = state->assume(*LV, true);
assert(state && "'this' cannot be null");
}
}
}
} while (0);
}
return state;
}

14
clang/test/Analysis/misc-ps-region-store.cpp
View File

@ -492,3 +492,17 @@ double PR11450() {
return NaN;
}
// Test that 'this' is assumed null upon analyzing the entry to a "top-level"
// function (i.e., when not analyzing from a specific caller).
struct TestNullThis {
int field;
void test();
};
void TestNullThis::test() {
int *p = &field;
if (p)
return;
field = 2; // no-warning
}