Use a proper visitor to recursively check for uninitialized use in constructors.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158477 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 12a63b1..f613542 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -23,6 +23,7 @@
#include "clang/AST/CharUnits.h"
#include "clang/AST/CXXInheritance.h"
#include "clang/AST/DeclVisitor.h"
+#include "clang/AST/EvaluatedExprVisitor.h"
#include "clang/AST/ExprCXX.h"
#include "clang/AST/RecordLayout.h"
#include "clang/AST/RecursiveASTVisitor.h"
@@ -2038,73 +2039,95 @@
<< (unsigned)IsPointer;
}
-/// Checks an initializer expression for use of uninitialized fields, such as
-/// containing the field that is being initialized. Returns true if there is an
-/// uninitialized field was used an updates the SourceLocation parameter; false
-/// otherwise.
-static bool InitExprContainsUninitializedFields(const Stmt *S,
- const ValueDecl *LhsField,
- SourceLocation *L) {
- assert(isa<FieldDecl>(LhsField) || isa<IndirectFieldDecl>(LhsField));
-
- if (isa<CallExpr>(S)) {
- // Do not descend into function calls or constructors, as the use
- // of an uninitialized field may be valid. One would have to inspect
- // the contents of the function/ctor to determine if it is safe or not.
- // i.e. Pass-by-value is never safe, but pass-by-reference and pointers
- // may be safe, depending on what the function/ctor does.
- return false;
- }
- if (const MemberExpr *ME = dyn_cast<MemberExpr>(S)) {
- const NamedDecl *RhsField = ME->getMemberDecl();
-
- if (const VarDecl *VD = dyn_cast<VarDecl>(RhsField)) {
- // The member expression points to a static data member.
- assert(VD->isStaticDataMember() &&
- "Member points to non-static data member!");
- (void)VD;
- return false;
- }
-
- if (isa<EnumConstantDecl>(RhsField)) {
- // The member expression points to an enum.
- return false;
+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) {
}
- if (RhsField == LhsField) {
- // Initializing a field with itself. Throw a warning.
- // But wait; there are exceptions!
- // Exception #1: The field may not belong to this record.
- // e.g. Foo(const Foo& rhs) : A(rhs.A) {}
- const Expr *base = ME->getBase();
- if (base != NULL && !isa<CXXThisExpr>(base->IgnoreParenCasts())) {
- // Even though the field matches, it does not belong to this record.
- return false;
+ 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)) {
+ S.Diag(ME->getExprLoc(), diag::warn_field_is_uninit);
+ return;
+ }
}
- // None of the exceptions triggered; return true to indicate an
- // uninitialized field was used.
- *L = ME->getMemberLoc();
- return true;
+
+ 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;
+ }
+ }
}
- } else if (isa<UnaryExprOrTypeTraitExpr>(S)) {
- // sizeof/alignof doesn't reference contents, do not warn.
- return false;
- } else if (const UnaryOperator *UOE = dyn_cast<UnaryOperator>(S)) {
- // address-of doesn't reference contents (the pointer may be dereferenced
- // in the same expression but it would be rare; and weird).
- if (UOE->getOpcode() == UO_AddrOf)
- return false;
- }
- for (Stmt::const_child_range it = S->children(); it; ++it) {
- if (!*it) {
- // An expression such as 'member(arg ?: "")' may trigger this.
- continue;
+
+ void VisitImplicitCastExpr(ImplicitCastExpr *E) {
+ if (E->getCastKind() == CK_LValueToRValue)
+ HandleValue(E->getSubExpr());
+
+ Inherited::VisitImplicitCastExpr(E);
}
- if (InitExprContainsUninitializedFields(*it, LhsField, L))
- return true;
+
+ 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);
}
- return false;
-}
+} // namespace
MemInitResult
Sema::BuildMemberInitializer(ValueDecl *Member, Expr *Init,
@@ -2153,18 +2176,16 @@
}
}
- for (unsigned i = 0; i < NumArgs; ++i) {
- SourceLocation L;
- if (InitExprContainsUninitializedFields(Args[i], Member, &L)) {
- // FIXME: Return true in the case when other fields are used before being
+ if (getDiagnostics().getDiagnosticLevel(diag::warn_field_is_uninit, IdLoc)
+ != 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
// 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.
- Diag(L, diag::warn_field_is_uninit);
- }
- }
+ CheckInitExprContainsUninitializedFields(*this, Args[i], Member);
SourceRange InitRange = Init->getSourceRange();