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//===----- EvaluationResult.cpp - Result class for the VM ------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "EvaluationResult.h"
#include "InterpState.h"
#include "Record.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include <iterator>
namespace clang {
namespace interp {
APValue EvaluationResult::toAPValue() const {
assert(!empty());
switch (Kind) {
case LValue:
// Either a pointer or a function pointer.
if (const auto *P = std::get_if<Pointer>(&Value))
return P->toAPValue(Ctx->getASTContext());
else if (const auto *FP = std::get_if<FunctionPointer>(&Value))
return FP->toAPValue(Ctx->getASTContext());
else
llvm_unreachable("Unhandled LValue type");
break;
case RValue:
return std::get<APValue>(Value);
case Valid:
return APValue();
default:
llvm_unreachable("Unhandled result kind?");
}
}
std::optional<APValue> EvaluationResult::toRValue() const {
if (Kind == RValue)
return toAPValue();
assert(Kind == LValue);
// We have a pointer and want an RValue.
if (const auto *P = std::get_if<Pointer>(&Value))
return P->toRValue(*Ctx, getSourceType());
else if (const auto *FP = std::get_if<FunctionPointer>(&Value)) // Nope
return FP->toAPValue(Ctx->getASTContext());
llvm_unreachable("Unhandled lvalue kind");
}
static void DiagnoseUninitializedSubobject(InterpState &S, SourceLocation Loc,
const FieldDecl *SubObjDecl) {
assert(SubObjDecl && "Subobject declaration does not exist");
S.FFDiag(Loc, diag::note_constexpr_uninitialized)
<< /*(name)*/ 1 << SubObjDecl;
S.Note(SubObjDecl->getLocation(),
diag::note_constexpr_subobject_declared_here);
}
static bool CheckFieldsInitialized(InterpState &S, SourceLocation Loc,
const Pointer &BasePtr, const Record *R);
static bool CheckArrayInitialized(InterpState &S, SourceLocation Loc,
const Pointer &BasePtr,
const ConstantArrayType *CAT) {
bool Result = true;
size_t NumElems = CAT->getZExtSize();
QualType ElemType = CAT->getElementType();
if (ElemType->isRecordType()) {
const Record *R = BasePtr.getElemRecord();
for (size_t I = 0; I != NumElems; ++I) {
Pointer ElemPtr = BasePtr.atIndex(I).narrow();
Result &= CheckFieldsInitialized(S, Loc, ElemPtr, R);
}
} else if (const auto *ElemCAT = dyn_cast<ConstantArrayType>(ElemType)) {
for (size_t I = 0; I != NumElems; ++I) {
Pointer ElemPtr = BasePtr.atIndex(I).narrow();
Result &= CheckArrayInitialized(S, Loc, ElemPtr, ElemCAT);
}
} else {
for (size_t I = 0; I != NumElems; ++I) {
if (!BasePtr.atIndex(I).isInitialized()) {
DiagnoseUninitializedSubobject(S, Loc, BasePtr.getField());
Result = false;
}
}
}
return Result;
}
static bool CheckFieldsInitialized(InterpState &S, SourceLocation Loc,
const Pointer &BasePtr, const Record *R) {
assert(R);
bool Result = true;
// Check all fields of this record are initialized.
for (const Record::Field &F : R->fields()) {
Pointer FieldPtr = BasePtr.atField(F.Offset);
QualType FieldType = F.Decl->getType();
// Don't check inactive union members.
if (R->isUnion() && !FieldPtr.isActive())
continue;
if (FieldType->isRecordType()) {
Result &= CheckFieldsInitialized(S, Loc, FieldPtr, FieldPtr.getRecord());
} else if (FieldType->isIncompleteArrayType()) {
// Nothing to do here.
} else if (F.Decl->isUnnamedBitField()) {
// Nothing do do here.
} else if (FieldType->isArrayType()) {
const auto *CAT =
cast<ConstantArrayType>(FieldType->getAsArrayTypeUnsafe());
Result &= CheckArrayInitialized(S, Loc, FieldPtr, CAT);
} else if (!FieldPtr.isInitialized()) {
DiagnoseUninitializedSubobject(S, Loc, F.Decl);
Result = false;
}
}
// Check Fields in all bases
for (auto [I, B] : llvm::enumerate(R->bases())) {
Pointer P = BasePtr.atField(B.Offset);
if (!P.isInitialized()) {
const Descriptor *Desc = BasePtr.getDeclDesc();
if (const auto *CD = dyn_cast_if_present<CXXRecordDecl>(R->getDecl())) {
const auto &BS = *std::next(CD->bases_begin(), I);
SourceLocation TypeBeginLoc = BS.getBaseTypeLoc();
S.FFDiag(TypeBeginLoc, diag::note_constexpr_uninitialized_base)
<< B.Desc->getType() << SourceRange(TypeBeginLoc, BS.getEndLoc());
} else {
S.FFDiag(Desc->getLocation(), diag::note_constexpr_uninitialized_base)
<< B.Desc->getType();
}
return false;
}
Result &= CheckFieldsInitialized(S, Loc, P, B.R);
}
// TODO: Virtual bases
return Result;
}
bool EvaluationResult::checkFullyInitialized(InterpState &S,
const Pointer &Ptr) const {
assert(Source);
assert(empty());
if (Ptr.isZero())
return true;
// We can't inspect dead pointers at all. Return true here so we can
// diagnose them later.
if (!Ptr.isLive())
return true;
SourceLocation InitLoc;
if (const auto *D = dyn_cast<const Decl *>(Source))
InitLoc = cast<VarDecl>(D)->getAnyInitializer()->getExprLoc();
else if (const auto *E = dyn_cast<const Expr *>(Source))
InitLoc = E->getExprLoc();
if (const Record *R = Ptr.getRecord())
return CheckFieldsInitialized(S, InitLoc, Ptr, R);
if (const auto *CAT = dyn_cast_if_present<ConstantArrayType>(
Ptr.getType()->getAsArrayTypeUnsafe()))
return CheckArrayInitialized(S, InitLoc, Ptr, CAT);
return true;
}
static void collectBlocks(const Pointer &Ptr,
llvm::SetVector<const Block *> &Blocks) {
auto isUsefulPtr = [](const Pointer &P) -> bool {
return P.isLive() && !P.isZero() && !P.isDummy() && P.isDereferencable() &&
!P.isUnknownSizeArray() && !P.isOnePastEnd();
};
if (!isUsefulPtr(Ptr))
return;
Blocks.insert(Ptr.block());
const Descriptor *Desc = Ptr.getFieldDesc();
if (!Desc)
return;
if (const Record *R = Desc->ElemRecord) {
for (const Record::Field &F : R->fields()) {
const Pointer &FieldPtr = Ptr.atField(F.Offset);
assert(FieldPtr.block() == Ptr.block());
collectBlocks(FieldPtr, Blocks);
}
} else if (Desc->isPrimitive() && Desc->getPrimType() == PT_Ptr) {
const Pointer &Pointee = Ptr.deref<Pointer>();
if (isUsefulPtr(Pointee) && !Blocks.contains(Pointee.block()))
collectBlocks(Pointee, Blocks);
} else if (Desc->isPrimitiveArray() && Desc->getPrimType() == PT_Ptr) {
for (unsigned I = 0; I != Desc->getNumElems(); ++I) {
const Pointer &ElemPointee = Ptr.elem<Pointer>(I);
if (isUsefulPtr(ElemPointee) && !Blocks.contains(ElemPointee.block()))
collectBlocks(ElemPointee, Blocks);
}
} else if (Desc->isCompositeArray()) {
for (unsigned I = 0; I != Desc->getNumElems(); ++I) {
const Pointer &ElemPtr = Ptr.atIndex(I).narrow();
collectBlocks(ElemPtr, Blocks);
}
}
}
bool EvaluationResult::checkReturnValue(InterpState &S, const Context &Ctx,
const Pointer &Ptr,
const SourceInfo &Info) {
// Collect all blocks that this pointer (transitively) points to and
// return false if any of them is a dynamic block.
llvm::SetVector<const Block *> Blocks;
collectBlocks(Ptr, Blocks);
for (const Block *B : Blocks) {
if (B->isDynamic()) {
assert(B->getDescriptor());
assert(B->getDescriptor()->asExpr());
bool IsSubobj = !Ptr.isRoot() || Ptr.isArrayElement();
S.FFDiag(Info, diag::note_constexpr_dynamic_alloc)
<< Ptr.getType()->isReferenceType() << IsSubobj;
S.Note(B->getDescriptor()->asExpr()->getExprLoc(),
diag::note_constexpr_dynamic_alloc_here);
return false;
}
}
return true;
}
} // namespace interp
} // namespace clang
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