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//===--- InterpState.cpp - Interpreter for the constexpr 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 "InterpState.h"
#include "InterpFrame.h"
#include "InterpStack.h"
#include "Program.h"
#include "State.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclTemplate.h"
using namespace clang;
using namespace clang::interp;
InterpState::InterpState(State &Parent, Program &P, InterpStack &Stk,
Context &Ctx, SourceMapper *M)
: Parent(Parent), M(M), P(P), Stk(Stk), Ctx(Ctx), BottomFrame(*this),
Current(&BottomFrame) {}
InterpState::InterpState(State &Parent, Program &P, InterpStack &Stk,
Context &Ctx, const Function *Func)
: Parent(Parent), M(nullptr), P(P), Stk(Stk), Ctx(Ctx),
BottomFrame(*this, Func, nullptr, CodePtr(), Func->getArgSize()),
Current(&BottomFrame) {}
bool InterpState::inConstantContext() const {
if (ConstantContextOverride)
return *ConstantContextOverride;
return Parent.InConstantContext;
}
InterpState::~InterpState() {
while (Current && !Current->isBottomFrame()) {
InterpFrame *Next = Current->Caller;
delete Current;
Current = Next;
}
BottomFrame.destroyScopes();
while (DeadBlocks) {
DeadBlock *Next = DeadBlocks->Next;
std::free(DeadBlocks);
DeadBlocks = Next;
}
}
void InterpState::cleanup() {
// As a last resort, make sure all pointers still pointing to a dead block
// don't point to it anymore.
for (DeadBlock *DB = DeadBlocks; DB; DB = DB->Next) {
for (Pointer *P = DB->B.Pointers; P; P = P->asBlockPointer().Next) {
P->PointeeStorage.BS.Pointee = nullptr;
}
}
Alloc.cleanup();
}
Frame *InterpState::getCurrentFrame() {
if (Current && Current->Caller)
return Current;
return Parent.getCurrentFrame();
}
bool InterpState::reportOverflow(const Expr *E, const llvm::APSInt &Value) {
QualType Type = E->getType();
CCEDiag(E, diag::note_constexpr_overflow) << Value << Type;
return noteUndefinedBehavior();
}
void InterpState::deallocate(Block *B) {
assert(B);
// The block might have a pointer saved in a field in its data
// that points to the block itself. We call the dtor first,
// which will destroy all the data but leave InlineDescriptors
// intact. If the block THEN still has pointers, we create a
// DeadBlock for it.
if (B->IsInitialized)
B->invokeDtor();
if (B->hasPointers()) {
size_t Size = B->getSize();
// Allocate a new block, transferring over pointers.
char *Memory =
reinterpret_cast<char *>(std::malloc(sizeof(DeadBlock) + Size));
auto *D = new (Memory) DeadBlock(DeadBlocks, B);
// Since the block doesn't hold any actual data anymore, we can just
// memcpy() everything over.
std::memcpy(D->rawData(), B->rawData(), B->getSize());
D->B.IsInitialized = B->IsInitialized;
// We moved the contents over to the DeadBlock.
B->IsInitialized = false;
}
}
bool InterpState::maybeDiagnoseDanglingAllocations() {
bool NoAllocationsLeft = !Alloc.hasAllocations();
if (!checkingPotentialConstantExpression()) {
for (const auto &[Source, Site] : Alloc.allocation_sites()) {
assert(!Site.empty());
CCEDiag(Source->getExprLoc(), diag::note_constexpr_memory_leak)
<< (Site.size() - 1) << Source->getSourceRange();
}
}
// Keep evaluating before C++20, since the CXXNewExpr wasn't valid there
// in the first place.
return NoAllocationsLeft || !getLangOpts().CPlusPlus20;
}
StdAllocatorCaller InterpState::getStdAllocatorCaller(StringRef Name) const {
for (const InterpFrame *F = Current; F; F = F->Caller) {
const Function *Func = F->getFunction();
if (!Func)
continue;
const auto *MD = dyn_cast_if_present<CXXMethodDecl>(Func->getDecl());
if (!MD)
continue;
const IdentifierInfo *FnII = MD->getIdentifier();
if (!FnII || !FnII->isStr(Name))
continue;
const auto *CTSD =
dyn_cast<ClassTemplateSpecializationDecl>(MD->getParent());
if (!CTSD)
continue;
const IdentifierInfo *ClassII = CTSD->getIdentifier();
const TemplateArgumentList &TAL = CTSD->getTemplateArgs();
if (CTSD->isInStdNamespace() && ClassII && ClassII->isStr("allocator") &&
TAL.size() >= 1 && TAL[0].getKind() == TemplateArgument::Type) {
QualType ElemType = TAL[0].getAsType();
const auto *NewCall = cast<CallExpr>(F->Caller->getExpr(F->getRetPC()));
return {NewCall, ElemType};
}
}
return {};
}
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