tbaeder updated this revision to Diff 516701.
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D149133/new/
https://reviews.llvm.org/D149133
Files:
clang/lib/AST/Interp/ByteCodeExprGen.cpp
clang/lib/AST/Interp/ByteCodeExprGen.h
clang/lib/AST/Interp/Interp.cpp
clang/lib/AST/Interp/Interp.h
clang/lib/AST/Interp/Opcodes.td
clang/lib/AST/Interp/Pointer.h
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
@@ -586,6 +586,58 @@
static_assert(test() == 1);
}
+namespace BaseToDerived {
+namespace A {
+ struct A {};
+ struct B : A { int n; };
+ struct C : B {};
+ C c = {};
+ constexpr C *pb = (C*)((A*)&c + 1); // expected-error {{must be initialized by a constant expression}} \
+ // expected-note {{cannot access derived class of pointer past the end of object}} \
+ // ref-error {{must be initialized by a constant expression}} \
+ // ref-note {{cannot access derived class of pointer past the end of object}}
+}
+namespace B {
+ struct A {};
+ struct Z {};
+ struct B : Z, A {
+ int n;
+ constexpr B() : n(10) {}
+ };
+ struct C : B {
+ constexpr C() : B() {}
+ };
+
+ constexpr C c = {};
+ constexpr const A *pa = &c;
+ constexpr const C *cp = (C*)pa;
+ constexpr const B *cb = (B*)cp;
+
+ static_assert(cb->n == 10);
+ static_assert(cp->n == 10);
+}
+
+namespace C {
+ struct Base { int *a; };
+ struct Base2 : Base { int f[12]; };
+
+ struct Middle1 { int b[3]; };
+ struct Middle2 : Base2 { char c; };
+ struct Middle3 : Middle2 { char g[3]; };
+ struct Middle4 { int f[3]; };
+ struct Middle5 : Middle4, Middle3 { char g2[3]; };
+
+ struct NotQuiteDerived : Middle1, Middle5 { bool d; };
+ struct Derived : NotQuiteDerived { int e; };
+
+ constexpr NotQuiteDerived NQD1 = {};
+
+ constexpr Middle5 *M4 = (Middle5*)((Base2*)&NQD1);
+ static_assert(M4->a == nullptr);
+ static_assert(M4->g2[0] == 0);
+}
+}
+
namespace VirtualDtors {
class A {
Index: clang/lib/AST/Interp/Pointer.h
===================================================================
--- clang/lib/AST/Interp/Pointer.h
+++ clang/lib/AST/Interp/Pointer.h
@@ -100,6 +100,14 @@
return Pointer(Pointee, Field, Field);
}
+ /// Subtract the given offset from the current Base and Offset
+ /// of the pointer.
+ Pointer atFieldSub(unsigned Off) const {
+ assert(Offset >= Off);
+ unsigned O = Offset - Off;
+ return Pointer(Pointee, O, O);
+ }
+
/// Restricts the scope of an array element pointer.
Pointer narrow() const {
// Null pointers cannot be narrowed.
Index: clang/lib/AST/Interp/Opcodes.td
===================================================================
--- clang/lib/AST/Interp/Opcodes.td
+++ clang/lib/AST/Interp/Opcodes.td
@@ -291,6 +291,10 @@
let Args = [ArgUint32];
}
+def GetPtrDerivedPop : Opcode {
+ let Args = [ArgUint32];
+}
+
// [Pointer] -> [Pointer]
def GetPtrVirtBase : Opcode {
// RecordDecl of base class.
Index: clang/lib/AST/Interp/Interp.h
===================================================================
--- clang/lib/AST/Interp/Interp.h
+++ clang/lib/AST/Interp/Interp.h
@@ -67,8 +67,9 @@
bool CheckRange(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
CheckSubobjectKind CSK);
-/// Checks if accessing a base of the given pointer is valid.
-bool CheckBase(InterpState &S, CodePtr OpPC, const Pointer &Ptr);
+/// Checks if accessing a base or derived record of the given pointer is valid.
+bool CheckBaseDerived(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
+ CheckSubobjectKind CSK);
/// Checks if a pointer points to const storage.
bool CheckConst(InterpState &S, CodePtr OpPC, const Pointer &Ptr);
@@ -1078,11 +1079,21 @@
return true;
}
+inline bool GetPtrDerivedPop(InterpState &S, CodePtr OpPC, uint32_t Off) {
+ const Pointer &Ptr = S.Stk.pop<Pointer>();
+ if (!CheckNull(S, OpPC, Ptr, CSK_Derived))
+ return false;
+ if (!CheckBaseDerived(S, OpPC, Ptr, CSK_Derived))
+ return false;
+ S.Stk.push<Pointer>(Ptr.atFieldSub(Off));
+ return true;
+}
+
inline bool GetPtrBase(InterpState &S, CodePtr OpPC, uint32_t Off) {
const Pointer &Ptr = S.Stk.peek<Pointer>();
if (!CheckNull(S, OpPC, Ptr, CSK_Base))
return false;
- if (!CheckBase(S, OpPC, Ptr))
+ if (!CheckBaseDerived(S, OpPC, Ptr, CSK_Base))
return false;
S.Stk.push<Pointer>(Ptr.atField(Off));
return true;
@@ -1092,7 +1103,7 @@
const Pointer &Ptr = S.Stk.pop<Pointer>();
if (!CheckNull(S, OpPC, Ptr, CSK_Base))
return false;
- if (!CheckBase(S, OpPC, Ptr))
+ if (!CheckBaseDerived(S, OpPC, Ptr, CSK_Base))
return false;
S.Stk.push<Pointer>(Ptr.atField(Off));
return true;
Index: clang/lib/AST/Interp/Interp.cpp
===================================================================
--- clang/lib/AST/Interp/Interp.cpp
+++ clang/lib/AST/Interp/Interp.cpp
@@ -211,12 +211,13 @@
return false;
}
-bool CheckBase(InterpState &S, CodePtr OpPC, const Pointer &Ptr) {
+bool CheckBaseDerived(InterpState &S, CodePtr OpPC, const Pointer &Ptr,
+ CheckSubobjectKind CSK) {
if (!Ptr.isOnePastEnd())
return true;
const SourceInfo &Loc = S.Current->getSource(OpPC);
- S.FFDiag(Loc, diag::note_constexpr_past_end_subobject) << CSK_Base;
+ S.FFDiag(Loc, diag::note_constexpr_past_end_subobject) << CSK;
return false;
}
Index: clang/lib/AST/Interp/ByteCodeExprGen.h
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.h
+++ clang/lib/AST/Interp/ByteCodeExprGen.h
@@ -269,8 +269,8 @@
}
bool emitRecordDestruction(const Descriptor *Desc);
- bool emitDerivedToBaseCasts(const RecordType *DerivedType,
- const RecordType *BaseType, const Expr *E);
+ unsigned collectBaseOffset(const RecordType *BaseType,
+ const RecordType *DerivedType);
bool emitBuiltinBitCast(const CastExpr *E);
protected:
Index: clang/lib/AST/Interp/ByteCodeExprGen.cpp
===================================================================
--- clang/lib/AST/Interp/ByteCodeExprGen.cpp
+++ clang/lib/AST/Interp/ByteCodeExprGen.cpp
@@ -138,8 +138,20 @@
if (!this->visit(SubExpr))
return false;
- return this->emitDerivedToBaseCasts(getRecordTy(SubExpr->getType()),
- getRecordTy(CE->getType()), CE);
+ unsigned DerivedOffset = collectBaseOffset(getRecordTy(CE->getType()),
+ getRecordTy(SubExpr->getType()));
+
+ return this->emitGetPtrBasePop(DerivedOffset, CE);
+ }
+
+ case CK_BaseToDerived: {
+ if (!this->visit(SubExpr))
+ return false;
+
+ unsigned DerivedOffset = collectBaseOffset(getRecordTy(SubExpr->getType()),
+ getRecordTy(CE->getType()));
+
+ return this->emitGetPtrDerivedPop(DerivedOffset, CE);
}
case CK_FloatingCast: {
@@ -2124,13 +2136,15 @@
}
template <class Emitter>
-bool ByteCodeExprGen<Emitter>::emitDerivedToBaseCasts(
- const RecordType *DerivedType, const RecordType *BaseType, const Expr *E) {
- // Pointer of derived type is already on the stack.
+unsigned
+ByteCodeExprGen<Emitter>::collectBaseOffset(const RecordType *BaseType,
+ const RecordType *DerivedType) {
const auto *FinalDecl = cast<CXXRecordDecl>(BaseType->getDecl());
const RecordDecl *CurDecl = DerivedType->getDecl();
const Record *CurRecord = getRecord(CurDecl);
assert(CurDecl && FinalDecl);
+
+ unsigned OffsetSum = 0;
for (;;) {
assert(CurRecord->getNumBases() > 0);
// One level up
@@ -2138,21 +2152,18 @@
const auto *BaseDecl = cast<CXXRecordDecl>(B.Decl);
if (BaseDecl == FinalDecl || BaseDecl->isDerivedFrom(FinalDecl)) {
- // This decl will lead us to the final decl, so emit a base cast.
- if (!this->emitGetPtrBasePop(B.Offset, E))
- return false;
-
+ OffsetSum += B.Offset;
CurRecord = B.R;
CurDecl = BaseDecl;
break;
}
}
if (CurDecl == FinalDecl)
- return true;
+ break;
}
- llvm_unreachable("Couldn't find the base class?");
- return false;
+ assert(OffsetSum > 0);
+ return OffsetSum;
}
/// When calling this, we have a pointer of the local-to-destroy
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