tbaeder created this revision.
tbaeder added reviewers: aaron.ballman, erichkeane, tahonermann, shafik.
Herald added a project: All.
tbaeder requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D147621
Files:
clang/lib/AST/Interp/Interp.cpp
clang/test/AST/Interp/records.cpp
Index: clang/test/AST/Interp/records.cpp
===================================================================
--- clang/test/AST/Interp/records.cpp
+++ clang/test/AST/Interp/records.cpp
@@ -664,6 +664,28 @@
};
#endif
+namespace MutableFields {
+ class Foo {
+ public:
+ constexpr Foo() : I(1) {}
+ mutable int I; // ref-note {{declared here}}
+ };
+
+
+ constexpr int foo() {
+ const Foo F;
+ F.I = 12;
+ return F.I;
+ }
+ static_assert(foo() == 12, "");
+
+ /// FIXME: This should also be rejected in the new interpreter.
+ constexpr Foo GlobalF;
+ constexpr int foo2() { // ref-error {{never produces a constant expression}}
+ return GlobalF.I; // ref-note {{read of mutable member 'I' is not allowed
in a constant expression}}
+ }
+}
+
/// FIXME: The following tests are broken.
/// They are using CXXDefaultInitExprs which contain a CXXThisExpr. The This
pointer
/// in those refers to the declaration we are currently initializing, *not*
the
Index: clang/lib/AST/Interp/Interp.cpp
===================================================================
--- clang/lib/AST/Interp/Interp.cpp
+++ clang/lib/AST/Interp/Interp.cpp
@@ -224,6 +224,14 @@
return true;
}
+ // Writing to mutable fields is fine even if the parent is
+ // declared const.
+ if (S.getLangOpts().CPlusPlus14) {
+ if (const auto *FD = dyn_cast<FieldDecl>(Ptr.getFieldDesc()->asDecl());
+ FD && FD->isMutable())
+ return true;
+ }
+
const QualType Ty = Ptr.getType();
const SourceInfo &Loc = S.Current->getSource(OpPC);
S.FFDiag(Loc, diag::note_constexpr_modify_const_type) << Ty;
@@ -236,6 +244,11 @@
return true;
}
+ // In C++14 onwards, it is permitted to read a mutable member whose
+ // lifetime began within the evaluation.
+ if (S.getLangOpts().CPlusPlus14)
+ return true;
+
const SourceInfo &Loc = S.Current->getSource(OpPC);
const FieldDecl *Field = Ptr.getField();
S.FFDiag(Loc, diag::note_constexpr_access_mutable, 1) << AK_Read << Field;
Index: clang/test/AST/Interp/records.cpp
===================================================================
--- clang/test/AST/Interp/records.cpp
+++ clang/test/AST/Interp/records.cpp
@@ -664,6 +664,28 @@
};
#endif
+namespace MutableFields {
+ class Foo {
+ public:
+ constexpr Foo() : I(1) {}
+ mutable int I; // ref-note {{declared here}}
+ };
+
+
+ constexpr int foo() {
+ const Foo F;
+ F.I = 12;
+ return F.I;
+ }
+ static_assert(foo() == 12, "");
+
+ /// FIXME: This should also be rejected in the new interpreter.
+ constexpr Foo GlobalF;
+ constexpr int foo2() { // ref-error {{never produces a constant expression}}
+ return GlobalF.I; // ref-note {{read of mutable member 'I' is not allowed in a constant expression}}
+ }
+}
+
/// FIXME: The following tests are broken.
/// They are using CXXDefaultInitExprs which contain a CXXThisExpr. The This pointer
/// in those refers to the declaration we are currently initializing, *not* the
Index: clang/lib/AST/Interp/Interp.cpp
===================================================================
--- clang/lib/AST/Interp/Interp.cpp
+++ clang/lib/AST/Interp/Interp.cpp
@@ -224,6 +224,14 @@
return true;
}
+ // Writing to mutable fields is fine even if the parent is
+ // declared const.
+ if (S.getLangOpts().CPlusPlus14) {
+ if (const auto *FD = dyn_cast<FieldDecl>(Ptr.getFieldDesc()->asDecl());
+ FD && FD->isMutable())
+ return true;
+ }
+
const QualType Ty = Ptr.getType();
const SourceInfo &Loc = S.Current->getSource(OpPC);
S.FFDiag(Loc, diag::note_constexpr_modify_const_type) << Ty;
@@ -236,6 +244,11 @@
return true;
}
+ // In C++14 onwards, it is permitted to read a mutable member whose
+ // lifetime began within the evaluation.
+ if (S.getLangOpts().CPlusPlus14)
+ return true;
+
const SourceInfo &Loc = S.Current->getSource(OpPC);
const FieldDecl *Field = Ptr.getField();
S.FFDiag(Loc, diag::note_constexpr_access_mutable, 1) << AK_Read << Field;
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