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[analyzer] Create a temp region when a method is called on a struct rvalue. 

An rvalue has no address, but calling a C++ member function requires a
'this' pointer. This commit makes the analyzer create a temporary region
in which to store the struct rvalue and use as a 'this' pointer whenever
a member function is called on an rvalue, which is essentially what
CodeGen does.

More of <rdar://problem/12137950>. The last part is tracking down the
C++ FIXME in array-struct-region.cpp.

llvm-svn: 164829
This commit is contained in:
Jordan Rose 2012-09-28 17:15:21 +00:00
parent e7126582a4
commit b559f18584
2 changed files with 40 additions and 22 deletions
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53
clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
View File

@ -1470,6 +1470,23 @@ void ExprEngine::VisitLvalArraySubscriptExpr(const ArraySubscriptExpr *A,
}
}
/// If the value of the given expression is a NonLoc, copy it into a new
/// temporary region, and replace the value of the expression with that.
static ProgramStateRef createTemporaryRegionIfNeeded(ProgramStateRef State,
const LocationContext *LC,
const Expr *E) {
SVal V = State->getSVal(E, LC);
if (isa<NonLoc>(V)) {
MemRegionManager &MRMgr = State->getStateManager().getRegionManager();
const MemRegion *R = MRMgr.getCXXTempObjectRegion(E, LC);
State = State->bindLoc(loc::MemRegionVal(R), V);
State = State->BindExpr(E, LC, loc::MemRegionVal(R));
}
return State;
}
/// VisitMemberExpr - Transfer function for member expressions.
void ExprEngine::VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
ExplodedNodeSet &TopDst) {
@ -1478,6 +1495,7 @@ void ExprEngine::VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
ExplodedNodeSet Dst;
Decl *member = M->getMemberDecl();
// Handle static member variables accessed via member syntax.
if (VarDecl *VD = dyn_cast<VarDecl>(member)) {
assert(M->isGLValue());
Bldr.takeNodes(Pred);
@ -1486,36 +1504,27 @@ void ExprEngine::VisitMemberExpr(const MemberExpr *M, ExplodedNode *Pred,
return;
}
ProgramStateRef state = Pred->getState();
const LocationContext *LCtx = Pred->getLocationContext();
Expr *BaseExpr = M->getBase()->IgnoreParens();
// Handle C++ method calls.
if (const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(member)) {
Bldr.takeNodes(Pred);
if (MD->isInstance())
state = createTemporaryRegionIfNeeded(state, LCtx, BaseExpr);
SVal MDVal = svalBuilder.getFunctionPointer(MD);
ProgramStateRef state =
Pred->getState()->BindExpr(M, Pred->getLocationContext(), MDVal);
state = state->BindExpr(M, LCtx, MDVal);
Bldr.generateNode(M, Pred, state);
return;
}
// Handle regular struct fields / member variables.
state = createTemporaryRegionIfNeeded(state, LCtx, BaseExpr);
SVal baseExprVal = state->getSVal(BaseExpr, LCtx);
FieldDecl *field = dyn_cast<FieldDecl>(member);
if (!field) // FIXME: skipping member expressions for non-fields
return;
Expr *baseExpr = M->getBase()->IgnoreParens();
ProgramStateRef state = Pred->getState();
const LocationContext *LCtx = Pred->getLocationContext();
SVal baseExprVal = state->getSVal(baseExpr, Pred->getLocationContext());
// If we're accessing a field of an rvalue, we need to treat it like a
// temporary object.
if (isa<NonLoc>(baseExprVal)) {
const MemRegion *R =
svalBuilder.getRegionManager().getCXXTempObjectRegion(baseExpr, LCtx);
SVal L = loc::MemRegionVal(R);
state = state->bindLoc(L, baseExprVal);
baseExprVal = L;
}
FieldDecl *field = cast<FieldDecl>(member);
SVal L = state->getLValue(field, baseExprVal);
if (M->isGLValue()) {
ExplodedNodeSet Tmp;

9
clang/test/Analysis/array-struct-region.cpp
View File

@ -1,5 +1,7 @@
// RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection -verify -x c %s
// RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection -verify -x c++ -analyzer-config c++-inlining=constructors %s
// RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection -DINLINE -verify -x c %s
// RUN: %clang_cc1 -analyze -analyzer-checker=core,alpha.core,debug.ExprInspection -DINLINE -verify -x c++ -analyzer-config c++-inlining=constructors %s
void clang_analyzer_eval(int);
@ -11,7 +13,14 @@ struct S {
#endif
};
#ifdef INLINE
struct S getS() {
struct S s = { 42 };
return s;
}
#else
struct S getS();
#endif
void testAssignment() {