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Warn about self references in in-class initializers. 

This makes Clang warn about self references in in-class initializers,
for example:

  struct S {
    int a = a + 42;
  };

This basically just moves UninitializedFieldVisitor up a bit in
SemaDeclCXX.cpp, and adds a call to it from ActOnCXXInClassMemberInitializer.

llvm-svn: 164131
This commit is contained in:
Hans Wennborg 2012-09-18 15:58:06 +00:00
parent eb2c8f0fc6
commit 44fd70a3ad
2 changed files with 128 additions and 95 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

195
clang/lib/Sema/SemaDeclCXX.cpp
View File

@ -1678,6 +1678,99 @@ Sema::ActOnCXXMemberDeclarator(Scope *S, AccessSpecifier AS, Declarator &D,
return Member;
}
namespace {
class UninitializedFieldVisitor
: public EvaluatedExprVisitor<UninitializedFieldVisitor> {
Sema &S;
ValueDecl *VD;
public:
typedef EvaluatedExprVisitor<UninitializedFieldVisitor> Inherited;
UninitializedFieldVisitor(Sema &S, ValueDecl *VD) : Inherited(S.Context),
S(S), VD(VD) {
}
void HandleExpr(Expr *E) {
if (!E) return;
// Expressions like x(x) sometimes lack the surrounding expressions
// but need to be checked anyways.
HandleValue(E);
Visit(E);
}
void HandleValue(Expr *E) {
E = E->IgnoreParens();
if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
if (isa<EnumConstantDecl>(ME->getMemberDecl()))
return;
Expr *Base = E;
while (isa<MemberExpr>(Base)) {
ME = dyn_cast<MemberExpr>(Base);
if (VarDecl *VarD = dyn_cast<VarDecl>(ME->getMemberDecl()))
if (VarD->hasGlobalStorage())
return;
Base = ME->getBase();
}
if (VD == ME->getMemberDecl() && isa<CXXThisExpr>(Base)) {
unsigned diag = VD->getType()->isReferenceType()
? diag::warn_reference_field_is_uninit
: diag::warn_field_is_uninit;
S.Diag(ME->getExprLoc(), diag);
return;
}
}
if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
HandleValue(CO->getTrueExpr());
HandleValue(CO->getFalseExpr());
return;
}
if (BinaryConditionalOperator *BCO =
dyn_cast<BinaryConditionalOperator>(E)) {
HandleValue(BCO->getCommon());
HandleValue(BCO->getFalseExpr());
return;
}
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
switch (BO->getOpcode()) {
default:
return;
case(BO_PtrMemD):
case(BO_PtrMemI):
HandleValue(BO->getLHS());
return;
case(BO_Comma):
HandleValue(BO->getRHS());
return;
}
}
}
void VisitImplicitCastExpr(ImplicitCastExpr *E) {
if (E->getCastKind() == CK_LValueToRValue)
HandleValue(E->getSubExpr());
Inherited::VisitImplicitCastExpr(E);
}
void VisitCXXMemberCallExpr(CXXMemberCallExpr *E) {
Expr *Callee = E->getCallee();
if (isa<MemberExpr>(Callee))
HandleValue(Callee);
Inherited::VisitCXXMemberCallExpr(E);
}
};
static void CheckInitExprContainsUninitializedFields(Sema &S, Expr *E,
ValueDecl *VD) {
UninitializedFieldVisitor(S, VD).HandleExpr(E);
}
} // namespace
/// ActOnCXXInClassMemberInitializer - This is invoked after parsing an
/// in-class initializer for a non-static C++ class member, and after
/// instantiating an in-class initializer in a class template. Such actions
@ -1701,6 +1794,11 @@ Sema::ActOnCXXInClassMemberInitializer(Decl *D, SourceLocation InitLoc,
return;
}
if (getDiagnostics().getDiagnosticLevel(diag::warn_field_is_uninit, InitLoc)
!= DiagnosticsEngine::Ignored) {
CheckInitExprContainsUninitializedFields(*this, InitExpr, FD);
}
ExprResult Init = InitExpr;
if (!FD->getType()->isDependentType() && !InitExpr->isTypeDependent() &&
!FD->getDeclContext()->isDependentContext()) {
@ -2065,99 +2163,6 @@ static void CheckForDanglingReferenceOrPointer(Sema &S, ValueDecl *Member,
<< (unsigned)IsPointer;
}
namespace {
class UninitializedFieldVisitor
: public EvaluatedExprVisitor<UninitializedFieldVisitor> {
Sema &S;
ValueDecl *VD;
public:
typedef EvaluatedExprVisitor<UninitializedFieldVisitor> Inherited;
UninitializedFieldVisitor(Sema &S, ValueDecl *VD) : Inherited(S.Context),
S(S), VD(VD) {
}
void HandleExpr(Expr *E) {
if (!E) return;
// Expressions like x(x) sometimes lack the surrounding expressions
// but need to be checked anyways.
HandleValue(E);
Visit(E);
}
void HandleValue(Expr *E) {
E = E->IgnoreParens();
if (MemberExpr *ME = dyn_cast<MemberExpr>(E)) {
if (isa<EnumConstantDecl>(ME->getMemberDecl()))
return;
Expr *Base = E;
while (isa<MemberExpr>(Base)) {
ME = dyn_cast<MemberExpr>(Base);
if (VarDecl *VarD = dyn_cast<VarDecl>(ME->getMemberDecl()))
if (VarD->hasGlobalStorage())
return;
Base = ME->getBase();
}
if (VD == ME->getMemberDecl() && isa<CXXThisExpr>(Base)) {
unsigned diag = VD->getType()->isReferenceType()
? diag::warn_reference_field_is_uninit
: diag::warn_field_is_uninit;
S.Diag(ME->getExprLoc(), diag);
return;
}
}
if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) {
HandleValue(CO->getTrueExpr());
HandleValue(CO->getFalseExpr());
return;
}
if (BinaryConditionalOperator *BCO =
dyn_cast<BinaryConditionalOperator>(E)) {
HandleValue(BCO->getCommon());
HandleValue(BCO->getFalseExpr());
return;
}
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) {
switch (BO->getOpcode()) {
default:
return;
case(BO_PtrMemD):
case(BO_PtrMemI):
HandleValue(BO->getLHS());
return;
case(BO_Comma):
HandleValue(BO->getRHS());
return;
}
}
}
void VisitImplicitCastExpr(ImplicitCastExpr *E) {
if (E->getCastKind() == CK_LValueToRValue)
HandleValue(E->getSubExpr());
Inherited::VisitImplicitCastExpr(E);
}
void VisitCXXMemberCallExpr(CXXMemberCallExpr *E) {
Expr *Callee = E->getCallee();
if (isa<MemberExpr>(Callee))
HandleValue(Callee);
Inherited::VisitCXXMemberCallExpr(E);
}
};
static void CheckInitExprContainsUninitializedFields(Sema &S, Expr *E,
ValueDecl *VD) {
UninitializedFieldVisitor(S, VD).HandleExpr(E);
}
} // namespace
MemInitResult
Sema::BuildMemberInitializer(ValueDecl *Member, Expr *Init,
SourceLocation IdLoc) {
@ -2191,11 +2196,13 @@ Sema::BuildMemberInitializer(ValueDecl *Member, Expr *Init,
!= DiagnosticsEngine::Ignored)
for (unsigned i = 0; i < NumArgs; ++i)
// FIXME: Warn about the case when other fields are used before being
// uninitialized. For example, let this field be the i'th field. When
// initialized. For example, let this field be the i'th field. When
// initializing the i'th field, throw a warning if any of the >= i'th
// fields are used, as they are not yet initialized.
// Right now we are only handling the case where the i'th field uses
// itself in its initializer.
// Also need to take into account that some fields may be initialized by
// in-class initializers, see C++11 [class.base.init]p9.
CheckInitExprContainsUninitializedFields(*this, Args[i], Member);
SourceRange InitRange = Init->getSourceRange();

28
clang/test/SemaCXX/uninitialized.cpp
View File

@ -379,6 +379,25 @@ namespace statics {
}
}
namespace in_class_initializers {
struct S {
S() : a(a + 1) {} // expected-warning{{field is uninitialized when used here}}
int a = 42; // Note: because a is in a member initializer list, this initialization is ignored.
};
struct T {
T() : b(a + 1) {} // No-warning.
int a = 42;
int b;
};
struct U {
U() : a(b + 1), b(a + 1) {} // FIXME: Warn here.
int a = 42; // Note: because a and b are in the member initializer list, these initializers are ignored.
int b = 1;
};
}
namespace references {
int &a = a; // expected-warning{{reference 'a' is not yet bound to a value when used within its own initialization}}
@ -394,6 +413,13 @@ namespace references {
struct T {
T() : a(b), b(a) {} // FIXME: Warn here.
int &a, &b;
int &c = c; // FIXME: Warn here.
int &c = c; // expected-warning{{reference is not yet bound to a value when used here}}
};
int x;
struct U {
U() : b(a) {} // No-warning.
int &a = x;
int &b;
};
}