mirror of
https://github.com/LadybirdBrowser/ladybird
synced 2026-05-12 09:56:45 +02:00
d4ed658429
The plan is to start caching compiled JS bytecode on disk. Before loading anything from a cache we need confidence that the bytes are structurally well-formed, since a corrupted or tampered-with cache file could otherwise hand the interpreter an out-of-bounds jump or a constant-pool index that points past the end of the table. This commit lays down the scaffolding for that validator. The walker lives in Rust (Libraries/LibJS/Rust/src/bytecode/validator.rs) so that it can share the existing Bytecode.def-driven layout machinery with the encoder. C++ calls into it through cbindgen, the same way the rest of the Rust pipeline is wired up. For now, the validator only does Pass 1: walk the byte stream, verify each instruction is 8-byte aligned, the opcode byte is in range, and the reported length keeps us inside the buffer. The length lookup is generated from Bytecode.def so fixed-length and variable-length instructions stay in sync with the rest of the codegen automatically. Per-field bounds checks (operands, labels, table indices, cache indices) and structural extras (basic block offsets, exception handlers, source map) come in follow-up commits. The validator runs after every successful compilation in debug and sanitizer builds, gated on !NDEBUG || HAS_ADDRESS_SANITIZER, so we get an extra sanity check on every executable the encoder produces without paying for it in release builds. Failure trips a VERIFY_NOT_REACHED with the offset, opcode, and error category logged via dbgln().
55 lines
1.3 KiB
C++
55 lines
1.3 KiB
C++
/*
|
|
* Copyright (c) 2021, Gunnar Beutner <gbeutner@serenityos.org>
|
|
*
|
|
* SPDX-License-Identifier: BSD-2-Clause
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <AK/DistinctNumeric.h>
|
|
#include <AK/Utf16String.h>
|
|
#include <AK/Vector.h>
|
|
|
|
namespace JS::Bytecode {
|
|
|
|
struct StringTableIndex {
|
|
static constexpr u32 invalid = 0xffffffffu;
|
|
bool is_valid() const { return value != invalid; }
|
|
u32 value { 0 };
|
|
};
|
|
|
|
class StringTable {
|
|
AK_MAKE_NONMOVABLE(StringTable);
|
|
AK_MAKE_NONCOPYABLE(StringTable);
|
|
|
|
public:
|
|
StringTable() = default;
|
|
|
|
StringTableIndex insert(Utf16String);
|
|
Utf16String const& get(StringTableIndex) const;
|
|
void dump() const;
|
|
bool is_empty() const { return m_strings.is_empty(); }
|
|
size_t size() const { return m_strings.size(); }
|
|
|
|
private:
|
|
Vector<Utf16String> m_strings;
|
|
};
|
|
|
|
}
|
|
|
|
namespace AK {
|
|
|
|
template<>
|
|
struct SentinelOptionalTraits<JS::Bytecode::StringTableIndex> {
|
|
static constexpr JS::Bytecode::StringTableIndex sentinel_value() { return { JS::Bytecode::StringTableIndex::invalid }; }
|
|
static constexpr bool is_sentinel(JS::Bytecode::StringTableIndex const& value) { return !value.is_valid(); }
|
|
};
|
|
|
|
template<>
|
|
class Optional<JS::Bytecode::StringTableIndex> : public SentinelOptional<JS::Bytecode::StringTableIndex> {
|
|
public:
|
|
using SentinelOptional::SentinelOptional;
|
|
};
|
|
|
|
}
|