Skip to content

Commit

Permalink
src: update compile cache storage structure
Browse files Browse the repository at this point in the history 
This refactors the compile cache handler in preparation for the
JS API, and updates the compile cache storage structure into:

- $NODE_COMPILE_CACHE_DIR
  - $NODE_VERION-$ARCH-$CACHE_DATA_VERSION_TAG-$UID
    - $FILENAME_AND_MODULE_TYPE_HASH.cache

This also adds a magic number to the beginning of the cache
files for verification, and returns the status, compile
cache directory and/or error message of enabling the
compile cache in a structure, which can be converted as
JS counterparts by the upcoming JS API.

PR-URL: #54291
Refs: #53639
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ethan Arrowood <ethan@arrowood.dev>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
  • Loading branch information
@joyeecheung @RafaelGSS
joyeecheung authored and RafaelGSS committed Aug 21, 2024
1 parent 141e9fe commit e077ff1
Show file tree
Hide file tree
Showing 5 changed files with 137 additions and 62 deletions.
117 changes: 75 additions & 42 deletions src/compile_cache.cc
View file
Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
#include "compile_cache.h"
#include <string>
#include "debug_utils-inl.h"
#include "env-inl.h"
#include "node_file.h"
Expand Down Expand Up @@ -27,15 +28,19 @@ uint32_t GetHash(const char* data, size_t size) {
return crc32(crc, reinterpret_cast<const Bytef*>(data), size);
}

uint32_t GetCacheVersionTag() {
std::string_view node_version(NODE_VERSION);
uint32_t v8_tag = v8::ScriptCompiler::CachedDataVersionTag();
uLong crc = crc32(0L, Z_NULL, 0);
crc = crc32(crc, reinterpret_cast<const Bytef*>(&v8_tag), sizeof(uint32_t));
crc = crc32(crc,
reinterpret_cast<const Bytef*>(node_version.data()),
node_version.size());
return crc;
std::string GetCacheVersionTag() {
// On platforms where uids are available, use different folders for
// different users to avoid cache miss due to permission incompatibility.
// On platforms where uids are not available, bare with the cache miss.
// This should be fine on Windows, as there local directories tend to be
// user-specific.
std::string tag = std::string(NODE_VERSION) + '-' + std::string(NODE_ARCH) +
'-' +
Uint32ToHex(v8::ScriptCompiler::CachedDataVersionTag());
#ifdef NODE_IMPLEMENTS_POSIX_CREDENTIALS
tag += '-' + std::to_string(getuid());
#endif
return tag;
}

uint32_t GetCacheKey(std::string_view filename, CachedCodeType type) {
Expand Down Expand Up @@ -63,6 +68,10 @@ v8::ScriptCompiler::CachedData* CompileCacheEntry::CopyCache() const {
data, cache_size, v8::ScriptCompiler::CachedData::BufferOwned);
}

// Used for identifying and verifying a file is a compile cache file.
// See comments in CompileCacheHandler::Persist().
constexpr uint32_t kCacheMagicNumber = 0x8adfdbb2;

void CompileCacheHandler::ReadCacheFile(CompileCacheEntry* entry) {
Debug("[compile cache] reading cache from %s for %s %s...",
entry->cache_filename,
Expand Down Expand Up @@ -100,12 +109,20 @@ void CompileCacheHandler::ReadCacheFile(CompileCacheEntry* entry) {
return;
}

Debug("[%d %d %d %d]...",
Debug("[%d %d %d %d %d]...",
headers[kMagicNumberOffset],
headers[kCodeSizeOffset],
headers[kCacheSizeOffset],
headers[kCodeHashOffset],
headers[kCacheHashOffset]);

if (headers[kMagicNumberOffset] != kCacheMagicNumber) {
Debug("magic number mismatch: expected %d, actual %d\n",
kCacheMagicNumber,
headers[kMagicNumberOffset]);
return;
}

// Check the code size and hash which are already computed.
if (headers[kCodeSizeOffset] != entry->code_size) {
Debug("code size mismatch: expected %d, actual %d\n",
Expand Down Expand Up @@ -202,11 +219,14 @@ CompileCacheEntry* CompileCacheHandler::GetOrInsert(
compiler_cache_store_.emplace(key, std::make_unique<CompileCacheEntry>());
auto* result = emplaced.first->second.get();

std::u8string cache_filename_u8 =
(compile_cache_dir_ / Uint32ToHex(key)).u8string();
result->code_hash = code_hash;
result->code_size = code_utf8.length();
result->cache_key = key;
result->cache_filename =
(compile_cache_dir_ / Uint32ToHex(result->cache_key)).string();
std::string(cache_filename_u8.begin(), cache_filename_u8.end()) +
".cache";
result->source_filename = filename_utf8.ToString();
result->cache = nullptr;
result->type = type;
Expand Down Expand Up @@ -264,6 +284,7 @@ void CompileCacheHandler::MaybeSave(CompileCacheEntry* entry,
}

// Layout of a cache file:
// [uint32_t] magic number
// [uint32_t] code size
// [uint32_t] code hash
// [uint32_t] cache size
Expand Down Expand Up @@ -301,14 +322,16 @@ void CompileCacheHandler::Persist() {

// Generating headers.
std::vector<uint32_t> headers(kHeaderCount);
headers[kMagicNumberOffset] = kCacheMagicNumber;
headers[kCodeSizeOffset] = entry->code_size;
headers[kCacheSizeOffset] = cache_size;
headers[kCodeHashOffset] = entry->code_hash;
headers[kCacheHashOffset] = cache_hash;

Debug("[compile cache] writing cache for %s in %s [%d %d %d %d]...",
Debug("[compile cache] writing cache for %s in %s [%d %d %d %d %d]...",
entry->source_filename,
entry->cache_filename,
headers[kMagicNumberOffset],
headers[kCodeSizeOffset],
headers[kCacheSizeOffset],
headers[kCodeHashOffset],
Expand All @@ -335,53 +358,63 @@ CompileCacheHandler::CompileCacheHandler(Environment* env)

// Directory structure:
// - Compile cache directory (from NODE_COMPILE_CACHE)
// - <cache_version_tag_1>: hash of CachedDataVersionTag + NODE_VERESION
// - <cache_version_tag_2>
// - <cache_version_tag_3>
// - <cache_file_1>: a hash of filename + module type
// - <cache_file_2>
// - <cache_file_3>
bool CompileCacheHandler::InitializeDirectory(Environment* env,
const std::string& dir) {
compiler_cache_key_ = GetCacheVersionTag();
std::string compiler_cache_key_string = Uint32ToHex(compiler_cache_key_);
std::vector<std::string_view> paths = {dir, compiler_cache_key_string};
std::string cache_dir = PathResolve(env, paths);

// - $NODE_VERION-$ARCH-$CACHE_DATA_VERSION_TAG-$UID
// - $FILENAME_AND_MODULE_TYPE_HASH.cache: a hash of filename + module type
CompileCacheEnableResult CompileCacheHandler::Enable(Environment* env,
const std::string& dir) {
std::string cache_tag = GetCacheVersionTag();
std::string absolute_cache_dir_base = PathResolve(env, {dir});
std::filesystem::path cache_dir_with_tag =
std::filesystem::path(absolute_cache_dir_base) / cache_tag;
std::u8string cache_dir_with_tag_u8 = cache_dir_with_tag.u8string();
std::string cache_dir_with_tag_str(cache_dir_with_tag_u8.begin(),
cache_dir_with_tag_u8.end());
CompileCacheEnableResult result;
Debug("[compile cache] resolved path %s + %s -> %s\n",
dir,
compiler_cache_key_string,
cache_dir);
cache_tag,
cache_dir_with_tag_str);

if (UNLIKELY(!env->permission()->is_granted(
env, permission::PermissionScope::kFileSystemWrite, cache_dir))) {
Debug("[compile cache] skipping cache because write permission for %s "
"is not granted\n",
cache_dir);
return false;
env,
permission::PermissionScope::kFileSystemWrite,
cache_dir_with_tag_str))) {
result.message = "Skipping compile cache because write permission for " +
cache_dir_with_tag_str + " is not granted";
result.status = CompileCacheEnableStatus::kFailed;
return result;
}

if (UNLIKELY(!env->permission()->is_granted(
env, permission::PermissionScope::kFileSystemRead, cache_dir))) {
Debug("[compile cache] skipping cache because read permission for %s "
"is not granted\n",
cache_dir);
return false;
env,
permission::PermissionScope::kFileSystemRead,
cache_dir_with_tag_str))) {
result.message = "Skipping compile cache because read permission for " +
cache_dir_with_tag_str + " is not granted";
result.status = CompileCacheEnableStatus::kFailed;
return result;
}

fs::FSReqWrapSync req_wrap;
int err = fs::MKDirpSync(nullptr, &(req_wrap.req), cache_dir, 0777, nullptr);
int err = fs::MKDirpSync(
nullptr, &(req_wrap.req), cache_dir_with_tag_str, 0777, nullptr);
if (is_debug_) {
Debug("[compile cache] creating cache directory %s...%s\n",
cache_dir,
cache_dir_with_tag_str,
err < 0 ? uv_strerror(err) : "success");
}
if (err != 0 && err != UV_EEXIST) {
return false;
result.message =
"Cannot create cache directory: " + std::string(uv_strerror(err));
result.status = CompileCacheEnableStatus::kFailed;
return result;
}

compile_cache_dir_ = std::filesystem::path(cache_dir);
return true;
compile_cache_dir_str_ = absolute_cache_dir_base;
result.cache_directory = absolute_cache_dir_base;
compile_cache_dir_ = cache_dir_with_tag;
result.status = CompileCacheEnableStatus::kEnabled;
return result;
}

} // namespace node
36 changes: 27 additions & 9 deletions src/compile_cache.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
#include <filesystem>
#include <memory>
#include <string>
#include <string_view>
#include <unordered_map>
#include "v8.h"

Expand Down Expand Up @@ -34,10 +35,27 @@ struct CompileCacheEntry {
v8::ScriptCompiler::CachedData* CopyCache() const;
};

#define COMPILE_CACHE_STATUS(V) \
V(kFailed) /* Failed to enable the cache */ \
V(kEnabled) /* Was not enabled before, and now enabled. */ \
V(kAlreadyEnabled) /* Was already enabled. */

enum class CompileCacheEnableStatus : uint8_t {
#define V(status) status,
COMPILE_CACHE_STATUS(V)
#undef V
};

struct CompileCacheEnableResult {
CompileCacheEnableStatus status;
std::string cache_directory;
std::string message; // Set in case of failure.
};

class CompileCacheHandler {
public:
explicit CompileCacheHandler(Environment* env);
bool InitializeDirectory(Environment* env, const std::string& dir);
CompileCacheEnableResult Enable(Environment* env, const std::string& dir);

void Persist();

Expand All @@ -50,6 +68,7 @@ class CompileCacheHandler {
void MaybeSave(CompileCacheEntry* entry,
v8::Local<v8::Module> mod,
bool rejected);
std::string_view cache_dir() { return compile_cache_dir_str_; }

private:
void ReadCacheFile(CompileCacheEntry* entry);
Expand All @@ -62,19 +81,18 @@ class CompileCacheHandler {
template <typename... Args>
inline void Debug(const char* format, Args&&... args) const;

static constexpr size_t kCodeSizeOffset = 0;
static constexpr size_t kCacheSizeOffset = 1;
static constexpr size_t kCodeHashOffset = 2;
static constexpr size_t kCacheHashOffset = 3;
static constexpr size_t kHeaderCount = 4;
static constexpr size_t kMagicNumberOffset = 0;
static constexpr size_t kCodeSizeOffset = 1;
static constexpr size_t kCacheSizeOffset = 2;
static constexpr size_t kCodeHashOffset = 3;
static constexpr size_t kCacheHashOffset = 4;
static constexpr size_t kHeaderCount = 5;

v8::Isolate* isolate_ = nullptr;
bool is_debug_ = false;

std::string compile_cache_dir_str_;
std::filesystem::path compile_cache_dir_;
// The compile cache is stored in a directory whose name is the hex string of
// compiler_cache_key_.
uint32_t compiler_cache_key_ = 0;
std::unordered_map<uint32_t, std::unique_ptr<CompileCacheEntry>>
compiler_cache_store_;
};
Expand Down
37 changes: 29 additions & 8 deletions src/env.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1129,15 +1129,36 @@ void Environment::InitializeCompileCache() {
dir_from_env.empty()) {
return;
}
auto handler = std::make_unique<CompileCacheHandler>(this);
if (handler->InitializeDirectory(this, dir_from_env)) {
compile_cache_handler_ = std::move(handler);
AtExit(
[](void* env) {
static_cast<Environment*>(env)->compile_cache_handler()->Persist();
},
this);
EnableCompileCache(dir_from_env);
}

CompileCacheEnableResult Environment::EnableCompileCache(
const std::string& cache_dir) {
CompileCacheEnableResult result;

if (!compile_cache_handler_) {
std::unique_ptr<CompileCacheHandler> handler =
std::make_unique<CompileCacheHandler>(this);
result = handler->Enable(this, cache_dir);
if (result.status == CompileCacheEnableStatus::kEnabled) {
compile_cache_handler_ = std::move(handler);
AtExit(
[](void* env) {
static_cast<Environment*>(env)->compile_cache_handler()->Persist();
},
this);
}
if (!result.message.empty()) {
Debug(this,
DebugCategory::COMPILE_CACHE,
"[compile cache] %s\n",
result.message);
}
} else {
result.status = CompileCacheEnableStatus::kAlreadyEnabled;
result.cache_directory = compile_cache_handler_->cache_dir();
}
return result;
}

void Environment::ExitEnv(StopFlags::Flags flags) {
Expand Down
3 changes: 3 additions & 0 deletions src/env.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1028,6 +1028,9 @@ class Environment final : public MemoryRetainer {
inline CompileCacheHandler* compile_cache_handler();
inline bool use_compile_cache() const;
void InitializeCompileCache();
// Enable built-in compile cache if it has not yet been enabled.
// The cache will be persisted to disk on exit.
CompileCacheEnableResult EnableCompileCache(const std::string& cache_dir);

void RunAndClearNativeImmediates(bool only_refed = false);
void RunAndClearInterrupts();
Expand Down
6 changes: 3 additions & 3 deletions test/parallel/test-compile-cache-permission-disallowed.js
View file
Original file line number Diff line number Diff line change
Expand Up @@ -39,7 +39,7 @@ function testDisallowed(dummyDir, cacheDirInPermission, cacheDirInEnv) {
},
{
stderr(output) {
assert.match(output, /skipping cache because write permission for .* is not granted/);
assert.match(output, /Skipping compile cache because write permission for .* is not granted/);
return true;
}
});
Expand All @@ -63,7 +63,7 @@ function testDisallowed(dummyDir, cacheDirInPermission, cacheDirInEnv) {
},
{
stderr(output) {
assert.match(output, /skipping cache because write permission for .* is not granted/);
assert.match(output, /Skipping compile cache because write permission for .* is not granted/);
return true;
}
});
Expand All @@ -86,7 +86,7 @@ function testDisallowed(dummyDir, cacheDirInPermission, cacheDirInEnv) {
},
{
stderr(output) {
assert.match(output, /skipping cache because read permission for .* is not granted/);
assert.match(output, /Skipping compile cache because read permission for .* is not granted/);
return true;
}
});
Expand Down

0 comments on commit e077ff1

Please sign in to comment.