bevinh updated this revision to Diff 114340.
bevinh marked an inline comment as done.
bevinh added a comment.
Added a diag note for NestedConstMember.
https://reviews.llvm.org/D37254
Files:
include/clang/AST/Expr.h
include/clang/AST/Type.h
include/clang/Basic/DiagnosticSemaKinds.td
lib/AST/ExprClassification.cpp
lib/AST/Type.cpp
lib/Sema/SemaExpr.cpp
test/Sema/assign.c
Index: test/Sema/assign.c
===================================================================
--- test/Sema/assign.c
+++ test/Sema/assign.c
@@ -16,3 +16,46 @@
b[4] = 1; // expected-error {{read-only variable is not assignable}}
b2[4] = 1; // expected-error {{read-only variable is not assignable}}
}
+
+typedef struct I {
+ const int a; // expected-note 4{{nested data member 'a' declared const here}} \
+ expected-note 6{{data member 'a' declared const here}}
+} I;
+typedef struct J {
+ struct I i;
+} J;
+typedef struct K {
+ struct J *j;
+} K;
+
+void testI(struct I i1, struct I i2) {
+ i1 = i2; // expected-error {{cannot assign to variable 'i1' with const-qualified data member 'a'}}
+}
+void testJ1(struct J j1, struct J j2) {
+ j1 = j2; // expected-error {{cannot assign to variable 'j1' with nested const-qualified data member 'a'}}
+}
+void testJ2(struct J j, struct I i) {
+ j.i = i; // expected-error {{cannot assign to non-static data member 'i' with const-qualified data member 'a'}}
+}
+void testK1(struct K k, struct J j) {
+ *(k.j) = j; // expected-error {{cannot assign to lvalue with nested const-qualified data member 'a'}}
+}
+void testK2(struct K k, struct I i) {
+ k.j->i = i; // expected-error {{cannot assign to non-static data member 'i' with const-qualified data member 'a'}}
+}
+
+void testI_(I i1, I i2) {
+ i1 = i2; // expected-error {{cannot assign to variable 'i1' with const-qualified data member 'a'}}
+}
+void testJ1_(J j1, J j2) {
+ j1 = j2; // expected-error {{cannot assign to variable 'j1' with nested const-qualified data member 'a'}}
+}
+void testJ2_(J j, I i) {
+ j.i = i; // expected-error {{cannot assign to non-static data member 'i' with const-qualified data member 'a'}}
+}
+void testK1_(K k, J j) {
+ *(k.j) = j; // expected-error {{cannot assign to lvalue with nested const-qualified data member 'a'}}
+}
+void testK2_(K k, I i) {
+ k.j->i = i; // expected-error {{cannot assign to non-static data member 'i' with const-qualified data member 'a'}}
+}
Index: lib/Sema/SemaExpr.cpp
===================================================================
--- lib/Sema/SemaExpr.cpp
+++ lib/Sema/SemaExpr.cpp
@@ -10176,22 +10176,23 @@
return !Ty.isConstQualified();
}
+// Update err_typecheck_assign_const and note_typecheck_assign_const
+// when this enum is changed.
+enum {
+ ConstFunction,
+ ConstVariable,
+ ConstMember,
+ ConstMethod,
+ NestedConstMember,
+ ConstUnknown, // Keep as last element
+};
+
/// Emit the "read-only variable not assignable" error and print notes to give
/// more information about why the variable is not assignable, such as pointing
/// to the declaration of a const variable, showing that a method is const, or
/// that the function is returning a const reference.
static void DiagnoseConstAssignment(Sema &S, const Expr *E,
SourceLocation Loc) {
- // Update err_typecheck_assign_const and note_typecheck_assign_const
- // when this enum is changed.
- enum {
- ConstFunction,
- ConstVariable,
- ConstMember,
- ConstMethod,
- ConstUnknown, // Keep as last element
- };
-
SourceRange ExprRange = E->getSourceRange();
// Only emit one error on the first const found. All other consts will emit
@@ -10301,6 +10302,66 @@
S.Diag(Loc, diag::err_typecheck_assign_const) << ExprRange << ConstUnknown;
}
+enum OriginalExprKind {
+ OEK_Variable,
+ OEK_Member,
+ OEK_LValue
+};
+
+static void DiagnoseRecursiveConstFields(Sema &S, const ValueDecl *VD,
+ const RecordType *Ty,
+ SourceLocation Loc, SourceRange Range,
+ OriginalExprKind OEK,
+ bool &DiagnosticEmitted,
+ bool IsNested = false) {
+ // We walk the record hierarchy breadth-first to ensure that we print
+ // diagnostics in field nesting order.
+ // First, check every field for constness.
+ for (const FieldDecl *Field : Ty->getDecl()->fields()) {
+ if (Field->getType().isConstQualified()) {
+ if (!DiagnosticEmitted) {
+ S.Diag(Loc, diag::err_typecheck_assign_const)
+ << Range << NestedConstMember << OEK << VD
+ << IsNested << Field;
+ DiagnosticEmitted = true;
+ }
+ S.Diag(Field->getLocation(), diag::note_typecheck_assign_const)
+ << NestedConstMember << IsNested << Field
+ << Field->getType() << Field->getSourceRange();
+ }
+ }
+ // Then, recurse.
+ for (const FieldDecl *Field : Ty->getDecl()->fields()) {
+ QualType FTy = Field->getType();
+ if (const RecordType *FieldRecTy = FTy->getAs<RecordType>())
+ DiagnoseRecursiveConstFields(S, VD, FieldRecTy, Loc, Range,
+ OEK, DiagnosticEmitted, true);
+ }
+}
+
+/// Emit an error for the case where a record we are trying to assign to has a
+/// const-qualified field somewhere in its hierarchy.
+static void DiagnoseRecursiveConstFields(Sema &S, const Expr *E,
+ SourceLocation Loc) {
+ QualType Ty = E->getType();
+ assert(Ty->isRecordType() && "lvalue was not record?");
+ SourceRange Range = E->getSourceRange();
+ const RecordType *RTy = Ty.getCanonicalType()->getAs<RecordType>();
+ bool DiagEmitted = false;
+
+ if (const MemberExpr *ME = dyn_cast<MemberExpr>(E))
+ DiagnoseRecursiveConstFields(S, ME->getMemberDecl(), RTy, Loc,
+ Range, OEK_Member, DiagEmitted);
+ else if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
+ DiagnoseRecursiveConstFields(S, DRE->getDecl(), RTy, Loc,
+ Range, OEK_Variable, DiagEmitted);
+ else
+ DiagnoseRecursiveConstFields(S, nullptr, RTy, Loc,
+ Range, OEK_LValue, DiagEmitted);
+ if (!DiagEmitted)
+ DiagnoseConstAssignment(S, E, Loc);
+}
+
/// CheckForModifiableLvalue - Verify that E is a modifiable lvalue. If not,
/// emit an error and return true. If so, return false.
static bool CheckForModifiableLvalue(Expr *E, SourceLocation Loc, Sema &S) {
@@ -10376,6 +10437,9 @@
case Expr::MLV_ConstAddrSpace:
DiagnoseConstAssignment(S, E, Loc);
return true;
+ case Expr::MLV_ConstQualifiedField:
+ DiagnoseRecursiveConstFields(S, E, Loc);
+ return true;
case Expr::MLV_ArrayType:
case Expr::MLV_ArrayTemporary:
DiagID = diag::err_typecheck_array_not_modifiable_lvalue;
Index: lib/AST/Type.cpp
===================================================================
--- lib/AST/Type.cpp
+++ lib/AST/Type.cpp
@@ -2992,6 +2992,19 @@
return getDecl()->isBeingDefined();
}
+bool RecordType::hasConstFields() const {
+ for (FieldDecl *FD : getDecl()->fields()) {
+ QualType FieldTy = FD->getType();
+ if (FieldTy.isConstQualified())
+ return true;
+ FieldTy = FieldTy.getCanonicalType();
+ if (const RecordType *FieldRecTy = FieldTy->getAs<RecordType>())
+ if (FieldRecTy->hasConstFields())
+ return true;
+ }
+ return false;
+}
+
bool AttributedType::isQualifier() const {
switch (getAttrKind()) {
// These are type qualifiers in the traditional C sense: they annotate
Index: lib/AST/ExprClassification.cpp
===================================================================
--- lib/AST/ExprClassification.cpp
+++ lib/AST/ExprClassification.cpp
@@ -641,7 +641,7 @@
// Records with any const fields (recursively) are not modifiable.
if (const RecordType *R = CT->getAs<RecordType>())
if (R->hasConstFields())
- return Cl::CM_ConstQualified;
+ return Cl::CM_ConstQualifiedField;
return Cl::CM_Modifiable;
}
@@ -695,6 +695,7 @@
llvm_unreachable("CM_LValueCast and CL_LValue don't match");
case Cl::CM_NoSetterProperty: return MLV_NoSetterProperty;
case Cl::CM_ConstQualified: return MLV_ConstQualified;
+ case Cl::CM_ConstQualifiedField: return MLV_ConstQualifiedField;
case Cl::CM_ConstAddrSpace: return MLV_ConstAddrSpace;
case Cl::CM_ArrayType: return MLV_ArrayType;
case Cl::CM_IncompleteType: return MLV_IncompleteType;
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -5881,14 +5881,17 @@
"cannot assign to %select{non-|}1static data member %2 "
"with const-qualified type %3|"
"cannot assign to non-static data member within const member function %1|"
+ "cannot assign to %select{variable %2|non-static data member %2|lvalue}1 "
+ "with %select{|nested }3const-qualified data member %4|"
"read-only variable is not assignable}0">;
def note_typecheck_assign_const : Note<
"%select{"
"function %1 which returns const-qualified type %2 declared here|"
"variable %1 declared const here|"
"%select{non-|}1static data member %2 declared const here|"
- "member function %q1 is declared const here}0">;
+ "member function %q1 is declared const here|"
+ "%select{|nested }1data member %2 declared const here}0">;
def warn_mixed_sign_comparison : Warning<
"comparison of integers of different signs: %0 and %1">,
Index: include/clang/AST/Type.h
===================================================================
--- include/clang/AST/Type.h
+++ include/clang/AST/Type.h
@@ -3791,10 +3791,9 @@
return reinterpret_cast<RecordDecl*>(TagType::getDecl());
}
- // FIXME: This predicate is a helper to QualType/Type. It needs to
- // recursively check all fields for const-ness. If any field is declared
- // const, it needs to return false.
- bool hasConstFields() const { return false; }
+ /// Recursively check all fields in the record for const-ness. If any field
+ /// is declared const, return true. Otherwise, return false.
+ bool hasConstFields() const;
bool isSugared() const { return false; }
QualType desugar() const { return QualType(this, 0); }
Index: include/clang/AST/Expr.h
===================================================================
--- include/clang/AST/Expr.h
+++ include/clang/AST/Expr.h
@@ -275,6 +275,7 @@
MLV_LValueCast, // Specialized form of MLV_InvalidExpression.
MLV_IncompleteType,
MLV_ConstQualified,
+ MLV_ConstQualifiedField,
MLV_ConstAddrSpace,
MLV_ArrayType,
MLV_NoSetterProperty,
@@ -324,6 +325,7 @@
CM_LValueCast, // Same as CM_RValue, but indicates GCC cast-as-lvalue ext
CM_NoSetterProperty,// Implicit assignment to ObjC property without setter
CM_ConstQualified,
+ CM_ConstQualifiedField,
CM_ConstAddrSpace,
CM_ArrayType,
CM_IncompleteType
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