llvm-project/clang/lib/AST/ByteCode/InterpState.cpp
Timm Baeder 06130ed341
Reapply "[clang][bytecode] Stack-allocate bottom function frame" (#12… (#125349)
…5325)

Move the BottomFrame to InterpState instead.
2025-02-01 18:12:35 +01:00

118 lines
3.5 KiB
C++

//===--- 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"
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->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);
const Descriptor *Desc = B->getDescriptor();
assert(Desc);
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);
std::memset(D->B.rawData(), 0, D->B.getSize());
// Move data and metadata from the old block to the new (dead)block.
if (B->IsInitialized && Desc->MoveFn) {
Desc->MoveFn(B, B->data(), D->data(), Desc);
if (Desc->getMetadataSize() > 0)
std::memcpy(D->rawData(), B->rawData(), Desc->getMetadataSize());
}
D->B.IsInitialized = B->IsInitialized;
// We moved the contents over to the DeadBlock.
B->IsInitialized = false;
} else if (B->IsInitialized) {
B->invokeDtor();
}
}
bool InterpState::maybeDiagnoseDanglingAllocations() {
bool NoAllocationsLeft = (Alloc.getNumAllocations() == 0);
if (!checkingPotentialConstantExpression()) {
for (const auto &It : Alloc.allocation_sites()) {
assert(It.second.size() > 0);
const Expr *Source = It.first;
CCEDiag(Source->getExprLoc(), diag::note_constexpr_memory_leak)
<< (It.second.size() - 1) << Source->getSourceRange();
}
}
return NoAllocationsLeft;
}