79 lines
1.8 KiB
C++
79 lines
1.8 KiB
C++
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//===--- InterpStack.cpp - Stack implementation for the VM ------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#include <cassert>
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#include <cstdlib>
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#include "InterpStack.h"
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using namespace clang;
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using namespace clang::interp;
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InterpStack::~InterpStack() {
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clear();
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}
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void InterpStack::clear() {
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if (Chunk && Chunk->Next)
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free(Chunk->Next);
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if (Chunk)
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free(Chunk);
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Chunk = nullptr;
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StackSize = 0;
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}
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void *InterpStack::grow(size_t Size) {
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assert(Size < ChunkSize - sizeof(StackChunk) && "Object too large");
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if (!Chunk || sizeof(StackChunk) + Chunk->size() + Size > ChunkSize) {
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if (Chunk && Chunk->Next) {
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Chunk = Chunk->Next;
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} else {
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StackChunk *Next = new (malloc(ChunkSize)) StackChunk(Chunk);
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if (Chunk)
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Chunk->Next = Next;
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Chunk = Next;
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}
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}
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auto *Object = reinterpret_cast<void *>(Chunk->End);
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Chunk->End += Size;
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StackSize += Size;
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return Object;
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}
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void *InterpStack::peek(size_t Size) {
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assert(Chunk && "Stack is empty!");
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StackChunk *Ptr = Chunk;
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while (Size > Ptr->size()) {
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Size -= Ptr->size();
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Ptr = Ptr->Prev;
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assert(Ptr && "Offset too large");
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}
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return reinterpret_cast<void *>(Ptr->End - Size);
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}
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void InterpStack::shrink(size_t Size) {
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assert(Chunk && "Chunk is empty!");
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while (Size > Chunk->size()) {
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Size -= Chunk->size();
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if (Chunk->Next) {
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free(Chunk->Next);
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Chunk->Next = nullptr;
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}
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Chunk->End = Chunk->start();
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Chunk = Chunk->Prev;
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assert(Chunk && "Offset too large");
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}
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Chunk->End -= Size;
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StackSize -= Size;
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}
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