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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /js/src/frontend/CompilationStencil.h
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'js/src/frontend/CompilationStencil.h')
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diff --git a/js/src/frontend/CompilationStencil.h b/js/src/frontend/CompilationStencil.h
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef frontend_CompilationStencil_h
+#define frontend_CompilationStencil_h
+
+#include "mozilla/AlreadyAddRefed.h" // already_AddRefed
+#include "mozilla/Assertions.h" // MOZ_ASSERT, MOZ_RELEASE_ASSERT, MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE
+#include "mozilla/Atomics.h" // mozilla::Atomic
+#include "mozilla/Attributes.h" // MOZ_RAII, MOZ_STACK_CLASS
+#include "mozilla/HashTable.h" // mozilla::HashMap, mozilla::DefaultHasher
+#include "mozilla/Maybe.h" // mozilla::Maybe
+#include "mozilla/MemoryReporting.h" // mozilla::MallocSizeOf
+#include "mozilla/RefPtr.h" // RefPtr
+#include "mozilla/Span.h" // mozilla::Span
+#include "mozilla/Variant.h" // mozilla::Variant
+
+#include <algorithm> // std::swap
+#include <stddef.h> // size_t
+#include <stdint.h> // uint32_t, uintptr_t
+#include <type_traits> // std::is_pointer_v
+#include <utility> // std::forward, std::move
+
+#include "ds/LifoAlloc.h" // LifoAlloc, LifoAllocScope
+#include "frontend/FrontendContext.h" // FrontendContext
+#include "frontend/FunctionSyntaxKind.h" // FunctionSyntaxKind
+#include "frontend/NameAnalysisTypes.h" // NameLocation
+#include "frontend/ParserAtom.h" // ParserAtomsTable, ParserAtomIndex, TaggedParserAtomIndex, ParserAtomSpan
+#include "frontend/ScopeIndex.h" // ScopeIndex
+#include "frontend/ScriptIndex.h" // ScriptIndex
+#include "frontend/SharedContext.h" // ThisBinding, InheritThis, Directives
+#include "frontend/Stencil.h" // ScriptStencil, ScriptStencilExtra, ScopeStencil, RegExpStencil, BigIntStencil, ObjLiteralStencil, BaseParserScopeData, StencilModuleMetadata
+#include "frontend/TaggedParserAtomIndexHasher.h" // TaggedParserAtomIndexHasher
+#include "frontend/UsedNameTracker.h" // UsedNameTracker
+#include "js/AllocPolicy.h" // SystemAllocPolicy, ReportOutOfMemory
+#include "js/GCVector.h" // JS::GCVector
+#include "js/RefCounted.h" // AtomicRefCounted
+#include "js/RootingAPI.h" // JS::Handle
+#include "js/Transcoding.h" // JS::TranscodeBuffer, JS::TranscodeRange
+#include "js/UniquePtr.h" // js::UniquePtr
+#include "js/Vector.h" // Vector
+#include "js/WasmModule.h" // JS::WasmModule
+#include "vm/FunctionFlags.h" // FunctionFlags
+#include "vm/GlobalObject.h" // GlobalObject
+#include "vm/JSContext.h" // JSContext
+#include "vm/JSFunction.h" // JSFunction
+#include "vm/JSScript.h" // BaseScript, ScriptSource, SourceExtent
+#include "vm/Realm.h" // JSContext::global
+#include "vm/Scope.h" // Scope, ModuleScope
+#include "vm/ScopeKind.h" // ScopeKind
+#include "vm/SharedStencil.h" // ImmutableScriptFlags, MemberInitializers, SharedImmutableScriptData, RO_IMMUTABLE_SCRIPT_FLAGS
+
+class JSAtom;
+class JSFunction;
+class JSObject;
+class JSString;
+class JSTracer;
+
+namespace JS {
+class JS_PUBLIC_API ReadOnlyCompileOptions;
+}
+
+namespace js {
+
+class AtomSet;
+class JSONPrinter;
+class ModuleObject;
+
+namespace frontend {
+
+struct CompilationInput;
+struct CompilationStencil;
+struct CompilationGCOutput;
+struct PreallocatedCompilationGCOutput;
+class ScriptStencilIterable;
+struct InputName;
+class ScopeBindingCache;
+
+// When delazifying modules' inner functions, the actual global scope is used.
+// However, when doing a delazification the global scope is not available. We
+// use this dummy type to be a placeholder to be used as part of the InputScope
+// variants to mimic what the Global scope would be used for.
+struct FakeStencilGlobalScope {};
+
+// Reference to a Scope within a CompilationStencil.
+struct ScopeStencilRef {
+ const CompilationStencil& context_;
+ const ScopeIndex scopeIndex_;
+
+ // Lookup the ScopeStencil referenced by this ScopeStencilRef.
+ inline const ScopeStencil& scope() const;
+};
+
+// Wraps a scope for a CompilationInput. The scope is either as a GC pointer to
+// an instantiated scope, or as a reference to a CompilationStencil.
+//
+// Note: A scope reference may be nullptr/InvalidIndex if there is no such
+// scope, such as the enclosingScope at the end of a scope chain. See `isNull`
+// helper.
+class InputScope {
+ using InputScopeStorage =
+ mozilla::Variant<Scope*, ScopeStencilRef, FakeStencilGlobalScope>;
+ InputScopeStorage scope_;
+
+ public:
+ // Create an InputScope given an instantiated scope.
+ explicit InputScope(Scope* ptr) : scope_(ptr) {}
+
+ // Create an InputScope for a global.
+ explicit InputScope(FakeStencilGlobalScope global) : scope_(global) {}
+
+ // Create an InputScope given a CompilationStencil and the ScopeIndex which is
+ // an offset within the same CompilationStencil given as argument.
+ InputScope(const CompilationStencil& context, ScopeIndex scopeIndex)
+ : scope_(ScopeStencilRef{context, scopeIndex}) {}
+
+ // Returns the variant used by the InputScope. This can be useful for complex
+ // cases where the following accessors are not enough.
+ const InputScopeStorage& variant() const { return scope_; }
+ InputScopeStorage& variant() { return scope_; }
+
+ // This match function will unwrap the variant for each type, and will
+ // specialize and call the Matcher given as argument with the type and value
+ // of the stored pointer / reference.
+ //
+ // This is useful for cases where the code is literally identical despite
+ // having different specializations. This is achiveable by relying on
+ // function overloading when the usage differ between the 2 types.
+ //
+ // Example:
+ // inputScope.match([](auto& scope) {
+ // // scope is either a `Scope*` or a `ScopeStencilRef`.
+ // for (auto bi = InputBindingIter(scope); bi; bi++) {
+ // InputName name(scope, bi.name());
+ // // ...
+ // }
+ // });
+ template <typename Matcher>
+ decltype(auto) match(Matcher&& matcher) const& {
+ return scope_.match(std::forward<Matcher>(matcher));
+ }
+ template <typename Matcher>
+ decltype(auto) match(Matcher&& matcher) & {
+ return scope_.match(std::forward<Matcher>(matcher));
+ }
+
+ bool isNull() const {
+ return scope_.match(
+ [](const Scope* ptr) { return !ptr; },
+ [](const ScopeStencilRef& ref) { return !ref.scopeIndex_.isValid(); },
+ [](const FakeStencilGlobalScope&) { return false; });
+ }
+
+ ScopeKind kind() const {
+ return scope_.match(
+ [](const Scope* ptr) { return ptr->kind(); },
+ [](const ScopeStencilRef& ref) { return ref.scope().kind(); },
+ [](const FakeStencilGlobalScope&) { return ScopeKind::Global; });
+ };
+ bool hasEnvironment() const {
+ return scope_.match(
+ [](const Scope* ptr) { return ptr->hasEnvironment(); },
+ [](const ScopeStencilRef& ref) { return ref.scope().hasEnvironment(); },
+ [](const FakeStencilGlobalScope&) {
+ // See Scope::hasEnvironment
+ return true;
+ });
+ };
+ inline InputScope enclosing() const;
+ bool hasOnChain(ScopeKind kind) const {
+ return scope_.match(
+ [=](const Scope* ptr) { return ptr->hasOnChain(kind); },
+ [=](const ScopeStencilRef& ref) {
+ ScopeStencilRef it = ref;
+ while (true) {
+ const ScopeStencil& scope = it.scope();
+ if (scope.kind() == kind) {
+ return true;
+ }
+ if (scope.kind() == ScopeKind::Module &&
+ kind == ScopeKind::Global) {
+ return true;
+ }
+ if (!scope.hasEnclosing()) {
+ break;
+ }
+ new (&it) ScopeStencilRef{ref.context_, scope.enclosing()};
+ }
+ return false;
+ },
+ [=](const FakeStencilGlobalScope&) {
+ return kind == ScopeKind::Global;
+ });
+ }
+ uint32_t environmentChainLength() const {
+ return scope_.match(
+ [](const Scope* ptr) { return ptr->environmentChainLength(); },
+ [](const ScopeStencilRef& ref) {
+ uint32_t length = 0;
+ ScopeStencilRef it = ref;
+ while (true) {
+ const ScopeStencil& scope = it.scope();
+ if (scope.hasEnvironment() &&
+ scope.kind() != ScopeKind::NonSyntactic) {
+ length++;
+ }
+ if (scope.kind() == ScopeKind::Module) {
+ // Stencil do not encode the Global scope, as it used to be
+ // assumed to already exists. As moving delazification off-thread,
+ // we need to materialize a fake-stencil version of the Global
+ // Scope.
+ MOZ_ASSERT(!scope.hasEnclosing());
+ length += js::ModuleScope::EnclosingEnvironmentChainLength;
+ }
+ if (!scope.hasEnclosing()) {
+ break;
+ }
+ new (&it) ScopeStencilRef{ref.context_, scope.enclosing()};
+ }
+ return length;
+ },
+ [=](const FakeStencilGlobalScope&) {
+ // Stencil-based delazification needs to calculate
+ // environmentChainLength where the global is not available.
+ //
+ // The FakeStencilGlobalScope is used to represent what the global
+ // would be if we had access to it while delazifying.
+ return uint32_t(js::ModuleScope::EnclosingEnvironmentChainLength);
+ });
+ }
+ void trace(JSTracer* trc);
+ bool isStencil() const { return !scope_.is<Scope*>(); };
+
+ // Various accessors which are valid only when the InputScope is a
+ // FunctionScope. Some of these accessors are returning values associated with
+ // the canonical function.
+ private:
+ inline FunctionFlags functionFlags() const;
+ inline ImmutableScriptFlags immutableFlags() const;
+
+ public:
+ inline MemberInitializers getMemberInitializers() const;
+ RO_IMMUTABLE_SCRIPT_FLAGS(immutableFlags())
+ bool isArrow() const { return functionFlags().isArrow(); }
+ bool allowSuperProperty() const {
+ return functionFlags().allowSuperProperty();
+ }
+ bool isClassConstructor() const {
+ return functionFlags().isClassConstructor();
+ }
+};
+
+// Reference to a Script within a CompilationStencil.
+struct ScriptStencilRef {
+ const CompilationStencil& context_;
+ const ScriptIndex scriptIndex_;
+
+ inline const ScriptStencil& scriptData() const;
+ inline const ScriptStencilExtra& scriptExtra() const;
+};
+
+// Wraps a script for a CompilationInput. The script is either as a BaseScript
+// pointer to an instantiated script, or as a reference to a CompilationStencil.
+class InputScript {
+ using InputScriptStorage = mozilla::Variant<BaseScript*, ScriptStencilRef>;
+ InputScriptStorage script_;
+
+ public:
+ // Create an InputScript given an instantiated BaseScript pointer.
+ explicit InputScript(BaseScript* ptr) : script_(ptr) {}
+
+ // Create an InputScript given a CompilationStencil and the ScriptIndex which
+ // is an offset within the same CompilationStencil given as argument.
+ InputScript(const CompilationStencil& context, ScriptIndex scriptIndex)
+ : script_(ScriptStencilRef{context, scriptIndex}) {}
+
+ const InputScriptStorage& raw() const { return script_; }
+ InputScriptStorage& raw() { return script_; }
+
+ SourceExtent extent() const {
+ return script_.match(
+ [](const BaseScript* ptr) { return ptr->extent(); },
+ [](const ScriptStencilRef& ref) { return ref.scriptExtra().extent; });
+ }
+ ImmutableScriptFlags immutableFlags() const {
+ return script_.match(
+ [](const BaseScript* ptr) { return ptr->immutableFlags(); },
+ [](const ScriptStencilRef& ref) {
+ return ref.scriptExtra().immutableFlags;
+ });
+ }
+ RO_IMMUTABLE_SCRIPT_FLAGS(immutableFlags())
+ FunctionFlags functionFlags() const {
+ return script_.match(
+ [](const BaseScript* ptr) { return ptr->function()->flags(); },
+ [](const ScriptStencilRef& ref) {
+ return ref.scriptData().functionFlags;
+ });
+ }
+ bool hasPrivateScriptData() const {
+ return script_.match(
+ [](const BaseScript* ptr) { return ptr->hasPrivateScriptData(); },
+ [](const ScriptStencilRef& ref) {
+ // See BaseScript::CreateRawLazy.
+ return ref.scriptData().hasGCThings() ||
+ ref.scriptExtra().useMemberInitializers();
+ });
+ }
+ InputScope enclosingScope() const {
+ return script_.match(
+ [](const BaseScript* ptr) {
+ return InputScope(ptr->function()->enclosingScope());
+ },
+ [](const ScriptStencilRef& ref) {
+ // The ScriptStencilRef only reference lazy Script, otherwise we
+ // should fetch the enclosing scope using the bodyScope field of the
+ // immutable data which is a reference to the vector of gc-things.
+ MOZ_RELEASE_ASSERT(!ref.scriptData().hasSharedData());
+ MOZ_ASSERT(ref.scriptData().hasLazyFunctionEnclosingScopeIndex());
+ auto scopeIndex = ref.scriptData().lazyFunctionEnclosingScopeIndex();
+ return InputScope(ref.context_, scopeIndex);
+ });
+ }
+ MemberInitializers getMemberInitializers() const {
+ return script_.match(
+ [](const BaseScript* ptr) { return ptr->getMemberInitializers(); },
+ [](const ScriptStencilRef& ref) {
+ return ref.scriptExtra().memberInitializers();
+ });
+ }
+
+ InputName displayAtom() const;
+ void trace(JSTracer* trc);
+ bool isNull() const {
+ return script_.match([](const BaseScript* ptr) { return !ptr; },
+ [](const ScriptStencilRef& ref) { return false; });
+ }
+ bool isStencil() const {
+ return script_.match([](const BaseScript* ptr) { return false; },
+ [](const ScriptStencilRef&) { return true; });
+ };
+};
+
+// Iterator for walking the scope chain, this is identical to ScopeIter but
+// accept an InputScope instead of a Scope pointer.
+//
+// It may be placed in GC containers; for example:
+//
+// for (Rooted<InputScopeIter> si(cx, InputScopeIter(scope)); si; si++) {
+// use(si);
+// SomeMayGCOperation();
+// use(si);
+// }
+//
+class MOZ_STACK_CLASS InputScopeIter {
+ InputScope scope_;
+
+ public:
+ explicit InputScopeIter(const InputScope& scope) : scope_(scope) {}
+
+ InputScope& scope() {
+ MOZ_ASSERT(!done());
+ return scope_;
+ }
+
+ const InputScope& scope() const {
+ MOZ_ASSERT(!done());
+ return scope_;
+ }
+
+ bool done() const { return scope_.isNull(); }
+ explicit operator bool() const { return !done(); }
+ void operator++(int) { scope_ = scope_.enclosing(); }
+ ScopeKind kind() const { return scope_.kind(); }
+
+ // Returns whether this scope has a syntactic environment (i.e., an
+ // Environment that isn't a non-syntactic With or NonSyntacticVariables)
+ // on the environment chain.
+ bool hasSyntacticEnvironment() const {
+ return scope_.hasEnvironment() && scope_.kind() != ScopeKind::NonSyntactic;
+ }
+
+ void trace(JSTracer* trc) { scope_.trace(trc); }
+};
+
+// Reference to a Binding Name within an existing CompilationStencil.
+// TaggedParserAtomIndex are in some cases indexes in the parserAtomData of the
+// CompilationStencil.
+struct NameStencilRef {
+ const CompilationStencil& context_;
+ const TaggedParserAtomIndex atomIndex_;
+};
+
+// Wraps a name for a CompilationInput. The name is either as a GC pointer to
+// a JSAtom, or a TaggedParserAtomIndex which might reference to a non-included.
+//
+// The constructor for this class are using an InputScope as argument. This
+// InputScope is made to fetch back the CompilationStencil associated with the
+// TaggedParserAtomIndex when using a Stencil as input.
+struct InputName {
+ using InputNameStorage = mozilla::Variant<JSAtom*, NameStencilRef>;
+ InputNameStorage variant_;
+
+ InputName(Scope*, JSAtom* ptr) : variant_(ptr) {}
+ InputName(const ScopeStencilRef& scope, TaggedParserAtomIndex index)
+ : variant_(NameStencilRef{scope.context_, index}) {}
+ InputName(BaseScript*, JSAtom* ptr) : variant_(ptr) {}
+ InputName(const ScriptStencilRef& script, TaggedParserAtomIndex index)
+ : variant_(NameStencilRef{script.context_, index}) {}
+
+ // Dummy for empty global.
+ InputName(const FakeStencilGlobalScope&, TaggedParserAtomIndex)
+ : variant_(static_cast<JSAtom*>(nullptr)) {}
+
+ // The InputName is either from an instantiated name, or from another
+ // CompilationStencil. This method interns the current name in the parser atom
+ // table of a CompilationState, which has a corresponding CompilationInput.
+ TaggedParserAtomIndex internInto(FrontendContext* fc,
+ ParserAtomsTable& parserAtoms,
+ CompilationAtomCache& atomCache);
+
+ // Compare an InputName, which is not yet interned, with `other` is either an
+ // interned name or a well-known or static string.
+ //
+ // The `otherCached` argument should be a reference to a JSAtom*, initialized
+ // to nullptr, which is used to cache the JSAtom representation of the `other`
+ // argument if needed. If a different `other` parameter is provided, the
+ // `otherCached` argument should be reset to nullptr.
+ bool isEqualTo(FrontendContext* fc, ParserAtomsTable& parserAtoms,
+ CompilationAtomCache& atomCache, TaggedParserAtomIndex other,
+ JSAtom** otherCached) const;
+
+ bool isNull() const {
+ return variant_.match(
+ [](JSAtom* ptr) { return !ptr; },
+ [](const NameStencilRef& ref) { return !ref.atomIndex_; });
+ }
+};
+
+// ScopeContext holds information derived from the scope and environment chains
+// to try to avoid the parser needing to traverse VM structures directly.
+struct ScopeContext {
+ // Cache: Scope -> (JSAtom/TaggedParserAtomIndex -> NameLocation)
+ //
+ // This cache maps the scope to a hash table which can lookup a name of the
+ // scope to the equivalent NameLocation.
+ ScopeBindingCache* scopeCache = nullptr;
+
+ // Generation number of the `scopeCache` collected before filling the cache
+ // with enclosing scope information.
+ //
+ // The generation number, obtained from `scopeCache->getCurrentGeneration()`
+ // is incremented each time the GC invalidate the content of the cache. The
+ // `scopeCache` can only be used when the generation number collected before
+ // filling the cache is identical to the generation number seen when querying
+ // the cached content.
+ size_t scopeCacheGen = 0;
+
+ // Class field initializer info if we are nested within a class constructor.
+ // We may be an combination of arrow and eval context within the constructor.
+ mozilla::Maybe<MemberInitializers> memberInitializers = {};
+
+ enum class EnclosingLexicalBindingKind {
+ Let,
+ Const,
+ CatchParameter,
+ Synthetic,
+ PrivateMethod,
+ };
+
+ using EnclosingLexicalBindingCache =
+ mozilla::HashMap<TaggedParserAtomIndex, EnclosingLexicalBindingKind,
+ TaggedParserAtomIndexHasher>;
+
+ // Cache of enclosing lexical bindings.
+ // Used only for eval.
+ mozilla::Maybe<EnclosingLexicalBindingCache> enclosingLexicalBindingCache_;
+
+ // A map of private names to NameLocations used to allow evals to
+ // provide correct private name semantics (particularly around early
+ // errors and private brand lookup).
+ using EffectiveScopePrivateFieldCache =
+ mozilla::HashMap<TaggedParserAtomIndex, NameLocation,
+ TaggedParserAtomIndexHasher>;
+
+ // Cache of enclosing class's private fields.
+ // Used only for eval.
+ mozilla::Maybe<EffectiveScopePrivateFieldCache>
+ effectiveScopePrivateFieldCache_;
+
+#ifdef DEBUG
+ bool enclosingEnvironmentIsDebugProxy_ = false;
+#endif
+
+ // How many hops required to navigate from 'enclosingScope' to effective
+ // scope.
+ uint32_t effectiveScopeHops = 0;
+
+ uint32_t enclosingScopeEnvironmentChainLength = 0;
+
+ // Eval and arrow scripts also inherit the "this" environment -- used by
+ // `super` expressions -- from their enclosing script. We count the number of
+ // environment hops needed to get from enclosing scope to the nearest
+ // appropriate environment. This value is undefined if the script we are
+ // compiling is not an eval or arrow-function.
+ uint32_t enclosingThisEnvironmentHops = 0;
+
+ // The kind of enclosing scope.
+ ScopeKind enclosingScopeKind = ScopeKind::Global;
+
+ // The type of binding required for `this` of the top level context, as
+ // indicated by the enclosing scopes of this parse.
+ //
+ // NOTE: This is computed based on the effective scope (defined above).
+ ThisBinding thisBinding = ThisBinding::Global;
+
+ // Eval and arrow scripts inherit certain syntax allowances from their
+ // enclosing scripts.
+ bool allowNewTarget = false;
+ bool allowSuperProperty = false;
+ bool allowSuperCall = false;
+ bool allowArguments = true;
+
+ // Indicates there is a 'class' or 'with' scope on enclosing scope chain.
+ bool inClass = false;
+ bool inWith = false;
+
+ // True if the enclosing scope is for FunctionScope of arrow function.
+ bool enclosingScopeIsArrow = false;
+
+ // True if the enclosing scope has environment.
+ bool enclosingScopeHasEnvironment = false;
+
+#ifdef DEBUG
+ // True if the enclosing scope has non-syntactic scope on chain.
+ bool hasNonSyntacticScopeOnChain = false;
+
+ // True if the enclosing scope has function scope where the function needs
+ // home object.
+ bool hasFunctionNeedsHomeObjectOnChain = false;
+#endif
+
+ bool init(FrontendContext* fc, CompilationInput& input,
+ ParserAtomsTable& parserAtoms, ScopeBindingCache* scopeCache,
+ InheritThis inheritThis, JSObject* enclosingEnv);
+
+ mozilla::Maybe<EnclosingLexicalBindingKind>
+ lookupLexicalBindingInEnclosingScope(TaggedParserAtomIndex name);
+
+ NameLocation searchInEnclosingScope(FrontendContext* fc,
+ CompilationInput& input,
+ ParserAtomsTable& parserAtoms,
+ TaggedParserAtomIndex name);
+
+ bool effectiveScopePrivateFieldCacheHas(TaggedParserAtomIndex name);
+ mozilla::Maybe<NameLocation> getPrivateFieldLocation(
+ TaggedParserAtomIndex name);
+
+ private:
+ void computeThisBinding(const InputScope& scope);
+ void computeThisEnvironment(const InputScope& enclosingScope);
+ void computeInScope(const InputScope& enclosingScope);
+ void cacheEnclosingScope(const InputScope& enclosingScope);
+ NameLocation searchInEnclosingScopeWithCache(FrontendContext* fc,
+ CompilationInput& input,
+ ParserAtomsTable& parserAtoms,
+ TaggedParserAtomIndex name);
+ NameLocation searchInEnclosingScopeNoCache(FrontendContext* fc,
+ CompilationInput& input,
+ ParserAtomsTable& parserAtoms,
+ TaggedParserAtomIndex name);
+
+ InputScope determineEffectiveScope(InputScope& scope, JSObject* environment);
+
+ bool cachePrivateFieldsForEval(FrontendContext* fc, CompilationInput& input,
+ JSObject* enclosingEnvironment,
+ const InputScope& effectiveScope,
+ ParserAtomsTable& parserAtoms);
+
+ bool cacheEnclosingScopeBindingForEval(FrontendContext* fc,
+ CompilationInput& input,
+ ParserAtomsTable& parserAtoms);
+
+ bool addToEnclosingLexicalBindingCache(FrontendContext* fc,
+ ParserAtomsTable& parserAtoms,
+ CompilationAtomCache& atomCache,
+ InputName& name,
+ EnclosingLexicalBindingKind kind);
+};
+
+struct CompilationAtomCache {
+ public:
+ using AtomCacheVector = JS::GCVector<JSString*, 0, js::SystemAllocPolicy>;
+
+ private:
+ // Atoms lowered into or converted from CompilationStencil.parserAtomData.
+ //
+ // This field is here instead of in CompilationGCOutput because atoms lowered
+ // from JSAtom is part of input (enclosing scope bindings, lazy function name,
+ // etc), and having 2 vectors in both input/output is error prone.
+ AtomCacheVector atoms_;
+
+ public:
+ JSString* getExistingStringAt(ParserAtomIndex index) const;
+ JSString* getExistingStringAt(JSContext* cx,
+ TaggedParserAtomIndex taggedIndex) const;
+ JSString* getStringAt(ParserAtomIndex index) const;
+
+ JSAtom* getExistingAtomAt(ParserAtomIndex index) const;
+ JSAtom* getExistingAtomAt(JSContext* cx,
+ TaggedParserAtomIndex taggedIndex) const;
+ JSAtom* getAtomAt(ParserAtomIndex index) const;
+
+ bool hasAtomAt(ParserAtomIndex index) const;
+ bool setAtomAt(FrontendContext* fc, ParserAtomIndex index, JSString* atom);
+ bool allocate(FrontendContext* fc, size_t length);
+
+ bool empty() const { return atoms_.empty(); }
+ size_t size() const { return atoms_.length(); }
+
+ void stealBuffer(AtomCacheVector& atoms);
+ void releaseBuffer(AtomCacheVector& atoms);
+
+ void trace(JSTracer* trc);
+
+ size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return atoms_.sizeOfExcludingThis(mallocSizeOf);
+ }
+};
+
+// Information associated with an extra binding provided to a global script.
+// See frontend::CompileGlobalScriptWithExtraBindings.
+struct ExtraBindingInfo {
+ // UTF-8 encoded name of the binding.
+ UniqueChars nameChars;
+
+ TaggedParserAtomIndex nameIndex;
+
+ // If the binding conflicts with global variable or global lexical variable,
+ // the binding is shadowed.
+ bool isShadowed = false;
+
+ ExtraBindingInfo(UniqueChars&& nameChars, bool isShadowed)
+ : nameChars(std::move(nameChars)), isShadowed(isShadowed) {}
+};
+
+using ExtraBindingInfoVector =
+ js::Vector<ExtraBindingInfo, 0, js::SystemAllocPolicy>;
+
+// Input of the compilation, including source and enclosing context.
+struct CompilationInput {
+ enum class CompilationTarget {
+ Global,
+ SelfHosting,
+ StandaloneFunction,
+ StandaloneFunctionInNonSyntacticScope,
+ Eval,
+ Module,
+ Delazification,
+ };
+ CompilationTarget target = CompilationTarget::Global;
+
+ const JS::ReadOnlyCompileOptions& options;
+
+ CompilationAtomCache atomCache;
+
+ private:
+ InputScript lazy_ = InputScript(nullptr);
+
+ // Extra bindings for the global script.
+ ExtraBindingInfoVector* maybeExtraBindings_ = nullptr;
+
+ public:
+ RefPtr<ScriptSource> source;
+
+ // * If the target is Global, null.
+ // * If the target is SelfHosting, null. Instantiation code for self-hosting
+ // will ignore this and use the appropriate empty global scope instead.
+ // * If the target is StandaloneFunction, an empty global scope.
+ // * If the target is StandaloneFunctionInNonSyntacticScope, the non-null
+ // enclosing scope of the function
+ // * If the target is Eval, the non-null enclosing scope of the `eval`.
+ // * If the target is Module, null that means empty global scope
+ // (See EmitterScope::checkEnvironmentChainLength)
+ // * If the target is Delazification, the non-null enclosing scope of
+ // the function
+ InputScope enclosingScope = InputScope(nullptr);
+
+ explicit CompilationInput(const JS::ReadOnlyCompileOptions& options)
+ : options(options) {}
+
+ private:
+ bool initScriptSource(FrontendContext* fc);
+
+ public:
+ bool initForGlobal(FrontendContext* fc) {
+ target = CompilationTarget::Global;
+ return initScriptSource(fc);
+ }
+
+ bool initForGlobalWithExtraBindings(
+ FrontendContext* fc, ExtraBindingInfoVector* maybeExtraBindings) {
+ MOZ_ASSERT(maybeExtraBindings);
+ target = CompilationTarget::Global;
+ maybeExtraBindings_ = maybeExtraBindings;
+ return initScriptSource(fc);
+ }
+
+ bool initForSelfHostingGlobal(FrontendContext* fc) {
+ target = CompilationTarget::SelfHosting;
+ return initScriptSource(fc);
+ }
+
+ bool initForStandaloneFunction(JSContext* cx, FrontendContext* fc) {
+ target = CompilationTarget::StandaloneFunction;
+ if (!initScriptSource(fc)) {
+ return false;
+ }
+ enclosingScope = InputScope(&cx->global()->emptyGlobalScope());
+ return true;
+ }
+
+ bool initForStandaloneFunctionInNonSyntacticScope(
+ FrontendContext* fc, JS::Handle<Scope*> functionEnclosingScope);
+
+ bool initForEval(FrontendContext* fc, JS::Handle<Scope*> evalEnclosingScope) {
+ target = CompilationTarget::Eval;
+ if (!initScriptSource(fc)) {
+ return false;
+ }
+ enclosingScope = InputScope(evalEnclosingScope);
+ return true;
+ }
+
+ bool initForModule(FrontendContext* fc) {
+ target = CompilationTarget::Module;
+ if (!initScriptSource(fc)) {
+ return false;
+ }
+ // The `enclosingScope` is the emptyGlobalScope.
+ return true;
+ }
+
+ void initFromLazy(JSContext* cx, BaseScript* lazyScript, ScriptSource* ss) {
+ MOZ_ASSERT(cx->compartment() == lazyScript->compartment());
+
+ // We can only compile functions whose parents have previously been
+ // compiled, because compilation requires full information about the
+ // function's immediately enclosing scope.
+ MOZ_ASSERT(lazyScript->isReadyForDelazification());
+ target = CompilationTarget::Delazification;
+ lazy_ = InputScript(lazyScript);
+ source = ss;
+ enclosingScope = lazy_.enclosingScope();
+ }
+
+ void initFromStencil(CompilationStencil& context, ScriptIndex scriptIndex,
+ ScriptSource* ss) {
+ target = CompilationTarget::Delazification;
+ lazy_ = InputScript(context, scriptIndex);
+ source = ss;
+ enclosingScope = lazy_.enclosingScope();
+ }
+
+ // Returns true if enclosingScope field is provided to init* function,
+ // instead of setting to empty global internally.
+ bool hasNonDefaultEnclosingScope() const {
+ return target == CompilationTarget::StandaloneFunctionInNonSyntacticScope ||
+ target == CompilationTarget::Eval ||
+ target == CompilationTarget::Delazification;
+ }
+
+ // Returns the enclosing scope provided to init* function.
+ // nullptr otherwise.
+ InputScope maybeNonDefaultEnclosingScope() const {
+ if (hasNonDefaultEnclosingScope()) {
+ return enclosingScope;
+ }
+ return InputScope(nullptr);
+ }
+
+ // The BaseScript* is needed when instantiating a lazy function.
+ // See InstantiateTopLevel and FunctionsFromExistingLazy.
+ InputScript lazyOuterScript() { return lazy_; }
+ BaseScript* lazyOuterBaseScript() { return lazy_.raw().as<BaseScript*>(); }
+
+ // The JSFunction* is needed when instantiating a lazy function.
+ // See FunctionsFromExistingLazy.
+ JSFunction* function() const {
+ return lazy_.raw().as<BaseScript*>()->function();
+ }
+
+ // When compiling an inner function, we want to know the unique identifier
+ // which identify a function. This is computed from the source extend.
+ SourceExtent extent() const { return lazy_.extent(); }
+
+ // See `BaseScript::immutableFlags_`.
+ ImmutableScriptFlags immutableFlags() const { return lazy_.immutableFlags(); }
+
+ RO_IMMUTABLE_SCRIPT_FLAGS(immutableFlags())
+
+ FunctionFlags functionFlags() const { return lazy_.functionFlags(); }
+
+ // When delazifying, return the kind of function which is defined.
+ FunctionSyntaxKind functionSyntaxKind() const;
+
+ bool hasPrivateScriptData() const {
+ // This is equivalent to: ngcthings != 0 || useMemberInitializers()
+ // See BaseScript::CreateRawLazy.
+ return lazy_.hasPrivateScriptData();
+ }
+
+ // Whether this CompilationInput is parsing the top-level of a script, or
+ // false if we are parsing an inner function.
+ bool isInitialStencil() { return lazy_.isNull(); }
+
+ // Whether this CompilationInput is parsing a specific function with already
+ // pre-parsed contextual information.
+ bool isDelazifying() { return target == CompilationTarget::Delazification; }
+
+ bool hasExtraBindings() const { return !!maybeExtraBindings_; }
+ ExtraBindingInfoVector& extraBindings() { return *maybeExtraBindings_; }
+ const ExtraBindingInfoVector& extraBindings() const {
+ return *maybeExtraBindings_;
+ }
+ bool internExtraBindings(FrontendContext* fc, ParserAtomsTable& parserAtoms);
+
+ void trace(JSTracer* trc);
+
+ // Size of dynamic data. Note that GC data is counted by GC and not here. We
+ // also ignore ScriptSource which is a shared RefPtr.
+ size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return atomCache.sizeOfExcludingThis(mallocSizeOf);
+ }
+ size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return mallocSizeOf(this) + sizeOfExcludingThis(mallocSizeOf);
+ }
+
+#if defined(DEBUG) || defined(JS_JITSPEW)
+ void dump() const;
+ void dump(js::JSONPrinter& json) const;
+ void dumpFields(js::JSONPrinter& json) const;
+#endif
+};
+
+// When compiling a function which was previously Syntaxly Parsed, we generated
+// some information which made it possible to skip over some parsing phases,
+// such as computing closed over bindings as well as parsing inner functions.
+// This class contains all information which is generated by the SyntaxParse and
+// reused in the FullParse.
+class CompilationSyntaxParseCache {
+ // When delazifying, we should prepare an array which contains all
+ // stencil-like gc-things such that it can be used by the parser.
+ //
+ // When compiling from a Stencil, this will alias the existing Stencil.
+ mozilla::Span<TaggedScriptThingIndex> cachedGCThings_;
+
+ // When delazifying, we should perpare an array which contains all
+ // stencil-like information about scripts, such that it can be used by the
+ // parser.
+ //
+ // When compiling from a Stencil, these will alias the existing Stencil.
+ mozilla::Span<ScriptStencil> cachedScriptData_;
+ mozilla::Span<ScriptStencilExtra> cachedScriptExtra_;
+
+ // When delazifying, we copy the atom, either from JSAtom, or from another
+ // Stencil into TaggedParserAtomIndex which are valid in this current
+ // CompilationState.
+ mozilla::Span<TaggedParserAtomIndex> closedOverBindings_;
+
+ // Atom of the function being compiled. This atom index is valid in the
+ // current CompilationState.
+ TaggedParserAtomIndex displayAtom_;
+
+ // Stencil-like data about the function which is being compiled.
+ ScriptStencilExtra funExtra_;
+
+#ifdef DEBUG
+ // Whether any of these data should be considered or not.
+ bool isInitialized = false;
+#endif
+
+ public:
+ // When doing a full-parse of an incomplete BaseScript*, we have to iterate
+ // over functions and closed-over bindings, to avoid costly recursive decent
+ // in inner functions. This function will clone the BaseScript* information to
+ // make it available as a stencil-like data to the full-parser.
+ mozilla::Span<TaggedParserAtomIndex> closedOverBindings() const {
+ MOZ_ASSERT(isInitialized);
+ return closedOverBindings_;
+ }
+ const ScriptStencil& scriptData(size_t functionIndex) const {
+ return cachedScriptData_[scriptIndex(functionIndex)];
+ }
+ const ScriptStencilExtra& scriptExtra(size_t functionIndex) const {
+ return cachedScriptExtra_[scriptIndex(functionIndex)];
+ }
+
+ // Return the name of the function being delazified, if any.
+ TaggedParserAtomIndex displayAtom() const {
+ MOZ_ASSERT(isInitialized);
+ return displayAtom_;
+ }
+
+ // Return the extra information about the function being delazified, if any.
+ const ScriptStencilExtra& funExtra() const {
+ MOZ_ASSERT(isInitialized);
+ return funExtra_;
+ }
+
+ // Initialize the SynaxParse cache given a LifoAlloc. The JSContext is only
+ // used for reporting allocation errors.
+ [[nodiscard]] bool init(FrontendContext* fc, LifoAlloc& alloc,
+ ParserAtomsTable& parseAtoms,
+ CompilationAtomCache& atomCache,
+ const InputScript& lazy);
+
+ private:
+ // Return the script index of a given inner function.
+ //
+ // WARNING: The ScriptIndex returned by this function corresponds to the index
+ // in the cachedScriptExtra_ and cachedScriptData_ spans. With the
+ // cachedGCThings_ span, these might be reference to an actual Stencil from
+ // another compilation. Thus, the ScriptIndex returned by this function should
+ // not be confused with any ScriptIndex from the CompilationState.
+ ScriptIndex scriptIndex(size_t functionIndex) const {
+ MOZ_ASSERT(isInitialized);
+ auto taggedScriptIndex = cachedGCThings_[functionIndex];
+ MOZ_ASSERT(taggedScriptIndex.isFunction());
+ return taggedScriptIndex.toFunction();
+ }
+
+ [[nodiscard]] bool copyFunctionInfo(FrontendContext* fc,
+ ParserAtomsTable& parseAtoms,
+ CompilationAtomCache& atomCache,
+ const InputScript& lazy);
+ [[nodiscard]] bool copyScriptInfo(FrontendContext* fc, LifoAlloc& alloc,
+ ParserAtomsTable& parseAtoms,
+ CompilationAtomCache& atomCache,
+ BaseScript* lazy);
+ [[nodiscard]] bool copyScriptInfo(FrontendContext* fc, LifoAlloc& alloc,
+ ParserAtomsTable& parseAtoms,
+ CompilationAtomCache& atomCache,
+ const ScriptStencilRef& lazy);
+ [[nodiscard]] bool copyClosedOverBindings(FrontendContext* fc,
+ LifoAlloc& alloc,
+ ParserAtomsTable& parseAtoms,
+ CompilationAtomCache& atomCache,
+ BaseScript* lazy);
+ [[nodiscard]] bool copyClosedOverBindings(FrontendContext* fc,
+ LifoAlloc& alloc,
+ ParserAtomsTable& parseAtoms,
+ CompilationAtomCache& atomCache,
+ const ScriptStencilRef& lazy);
+};
+
+// AsmJS scripts are very rare on-average, so we use a HashMap to associate
+// data with a ScriptStencil. The ScriptStencil has a flag to indicate if we
+// need to even do this lookup.
+using StencilAsmJSMap =
+ mozilla::HashMap<ScriptIndex, RefPtr<const JS::WasmModule>,
+ mozilla::DefaultHasher<ScriptIndex>,
+ js::SystemAllocPolicy>;
+
+struct StencilAsmJSContainer
+ : public js::AtomicRefCounted<StencilAsmJSContainer> {
+ StencilAsmJSMap moduleMap;
+
+ StencilAsmJSContainer() = default;
+
+ size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return moduleMap.shallowSizeOfExcludingThis(mallocSizeOf);
+ }
+ size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return mallocSizeOf(this) + sizeOfExcludingThis(mallocSizeOf);
+ }
+};
+
+// Store shared data for non-lazy script.
+struct SharedDataContainer {
+ // NOTE: While stored, we must hold a ref-count and care must be taken when
+ // updating or clearing the pointer.
+ using SingleSharedDataPtr = SharedImmutableScriptData*;
+
+ using SharedDataVector =
+ Vector<RefPtr<js::SharedImmutableScriptData>, 0, js::SystemAllocPolicy>;
+ using SharedDataVectorPtr = SharedDataVector*;
+
+ using SharedDataMap =
+ mozilla::HashMap<ScriptIndex, RefPtr<js::SharedImmutableScriptData>,
+ mozilla::DefaultHasher<ScriptIndex>,
+ js::SystemAllocPolicy>;
+ using SharedDataMapPtr = SharedDataMap*;
+
+ private:
+ enum {
+ SingleTag = 0,
+ VectorTag = 1,
+ MapTag = 2,
+ BorrowTag = 3,
+
+ TagMask = 3,
+ };
+
+ uintptr_t data_ = 0;
+
+ public:
+ // Defaults to SingleSharedData.
+ SharedDataContainer() = default;
+
+ SharedDataContainer(const SharedDataContainer&) = delete;
+ SharedDataContainer(SharedDataContainer&& other) noexcept {
+ std::swap(data_, other.data_);
+ MOZ_ASSERT(other.isEmpty());
+ }
+
+ SharedDataContainer& operator=(const SharedDataContainer&) = delete;
+ SharedDataContainer& operator=(SharedDataContainer&& other) noexcept {
+ std::swap(data_, other.data_);
+ MOZ_ASSERT(other.isEmpty());
+ return *this;
+ }
+
+ ~SharedDataContainer();
+
+ [[nodiscard]] bool initVector(FrontendContext* fc);
+ [[nodiscard]] bool initMap(FrontendContext* fc);
+
+ private:
+ [[nodiscard]] bool convertFromSingleToMap(FrontendContext* fc);
+
+ public:
+ bool isEmpty() const { return (data_) == SingleTag; }
+ bool isSingle() const { return (data_ & TagMask) == SingleTag; }
+ bool isVector() const { return (data_ & TagMask) == VectorTag; }
+ bool isMap() const { return (data_ & TagMask) == MapTag; }
+ bool isBorrow() const { return (data_ & TagMask) == BorrowTag; }
+
+ void setSingle(already_AddRefed<SharedImmutableScriptData>&& data) {
+ MOZ_ASSERT(isEmpty());
+ data_ = reinterpret_cast<uintptr_t>(data.take());
+ MOZ_ASSERT(isSingle());
+ MOZ_ASSERT(!isEmpty());
+ }
+
+ void setBorrow(SharedDataContainer* sharedData) {
+ MOZ_ASSERT(isEmpty());
+ data_ = reinterpret_cast<uintptr_t>(sharedData) | BorrowTag;
+ MOZ_ASSERT(isBorrow());
+ }
+
+ SingleSharedDataPtr asSingle() const {
+ MOZ_ASSERT(isSingle());
+ MOZ_ASSERT(!isEmpty());
+ static_assert(SingleTag == 0);
+ return reinterpret_cast<SingleSharedDataPtr>(data_);
+ }
+ SharedDataVectorPtr asVector() const {
+ MOZ_ASSERT(isVector());
+ return reinterpret_cast<SharedDataVectorPtr>(data_ & ~TagMask);
+ }
+ SharedDataMapPtr asMap() const {
+ MOZ_ASSERT(isMap());
+ return reinterpret_cast<SharedDataMapPtr>(data_ & ~TagMask);
+ }
+ SharedDataContainer* asBorrow() const {
+ MOZ_ASSERT(isBorrow());
+ return reinterpret_cast<SharedDataContainer*>(data_ & ~TagMask);
+ }
+
+ [[nodiscard]] bool prepareStorageFor(FrontendContext* fc,
+ size_t nonLazyScriptCount,
+ size_t allScriptCount);
+ [[nodiscard]] bool cloneFrom(FrontendContext* fc,
+ const SharedDataContainer& other);
+
+ // Returns index-th script's shared data, or nullptr if it doesn't have.
+ js::SharedImmutableScriptData* get(ScriptIndex index) const;
+
+ // Add data for index-th script and share it with VM.
+ [[nodiscard]] bool addAndShare(FrontendContext* fc, ScriptIndex index,
+ js::SharedImmutableScriptData* data);
+
+ // Add data for index-th script without sharing it with VM.
+ // The data should already be shared with VM.
+ //
+ // The data is supposed to be added from delazification.
+ [[nodiscard]] bool addExtraWithoutShare(FrontendContext* fc,
+ ScriptIndex index,
+ js::SharedImmutableScriptData* data);
+
+ // Dynamic memory associated with this container. Does not include the
+ // SharedImmutableScriptData since we are not the unique owner of it.
+ size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ if (isVector()) {
+ return asVector()->sizeOfIncludingThis(mallocSizeOf);
+ }
+ if (isMap()) {
+ return asMap()->shallowSizeOfIncludingThis(mallocSizeOf);
+ }
+ MOZ_ASSERT(isSingle() || isBorrow());
+ return 0;
+ }
+
+#if defined(DEBUG) || defined(JS_JITSPEW)
+ void dump() const;
+ void dump(js::JSONPrinter& json) const;
+ void dumpFields(js::JSONPrinter& json) const;
+#endif
+};
+
+struct ExtensibleCompilationStencil;
+
+// The top level struct of stencil specialized for non-extensible case.
+// Used as the compilation output, and also XDR decode output.
+//
+// In XDR decode output case, the span and not-owning pointer fields point
+// the internal LifoAlloc and the external XDR buffer.
+//
+// In BorrowingCompilationStencil usage, span and not-owning pointer fields
+// point the ExtensibleCompilationStencil and its LifoAlloc.
+//
+// The dependent XDR buffer or ExtensibleCompilationStencil must be kept
+// alive manually.
+//
+// See SMDOC in Stencil.h for more info.
+struct CompilationStencil {
+ friend struct ExtensibleCompilationStencil;
+
+ static constexpr ScriptIndex TopLevelIndex = ScriptIndex(0);
+
+ static constexpr size_t LifoAllocChunkSize = 512;
+
+ // The lifetime of this CompilationStencil may be managed by stack allocation,
+ // UniquePtr<T>, or RefPtr<T>. If a RefPtr is used, this ref-count will track
+ // the lifetime, otherwise it is ignored.
+ //
+ // NOTE: Internal code and public APIs use a mix of these different allocation
+ // modes.
+ //
+ // See: JS::StencilAddRef/Release
+ mutable mozilla::Atomic<uintptr_t> refCount{0};
+
+ private:
+ // On-heap ExtensibleCompilationStencil that this CompilationStencil owns,
+ // and this CompilationStencil borrows each data from.
+ UniquePtr<ExtensibleCompilationStencil> ownedBorrowStencil;
+
+ public:
+ enum class StorageType {
+ // Pointers and spans point LifoAlloc or owned buffer.
+ Owned,
+
+ // Pointers and spans point external data, such as XDR buffer, or not-owned
+ // ExtensibleCompilationStencil (see BorrowingCompilationStencil).
+ Borrowed,
+
+ // Pointers and spans point data owned by ownedBorrowStencil.
+ OwnedExtensible,
+ };
+ StorageType storageType = StorageType::Owned;
+
+ // Value of CanLazilyParse(CompilationInput) on compilation.
+ // Used during instantiation.
+ bool canLazilyParse = false;
+
+ // If this stencil is a delazification, this identifies location of the
+ // function in the source text.
+ using FunctionKey = SourceExtent::FunctionKey;
+ FunctionKey functionKey = SourceExtent::NullFunctionKey;
+
+ // This holds allocations that do not require destructors to be run but are
+ // live until the stencil is released.
+ LifoAlloc alloc;
+
+ // The source text holder for the script. This may be an empty placeholder if
+ // the code will fully parsed and options indicate the source will never be
+ // needed again.
+ RefPtr<ScriptSource> source;
+
+ // Stencil for all function and non-function scripts. The TopLevelIndex is
+ // reserved for the top-level script. This top-level may or may not be a
+ // function.
+ mozilla::Span<ScriptStencil> scriptData;
+
+ // Immutable data computed during initial compilation and never updated during
+ // delazification.
+ mozilla::Span<ScriptStencilExtra> scriptExtra;
+
+ mozilla::Span<TaggedScriptThingIndex> gcThingData;
+
+ // scopeData and scopeNames have the same size, and i-th scopeNames contains
+ // the names for the bindings contained in the slot defined by i-th scopeData.
+ mozilla::Span<ScopeStencil> scopeData;
+ mozilla::Span<BaseParserScopeData*> scopeNames;
+
+ // Hold onto the RegExpStencil, BigIntStencil, and ObjLiteralStencil that are
+ // allocated during parse to ensure correct destruction.
+ mozilla::Span<RegExpStencil> regExpData;
+ mozilla::Span<BigIntStencil> bigIntData;
+ mozilla::Span<ObjLiteralStencil> objLiteralData;
+
+ // List of parser atoms for this compilation. This may contain nullptr entries
+ // when round-tripping with XDR if the atom was generated in original parse
+ // but not used by stencil.
+ ParserAtomSpan parserAtomData;
+
+ // Variable sized container for bytecode and other immutable data. A valid
+ // stencil always contains at least an entry for `TopLevelIndex` script.
+ SharedDataContainer sharedData;
+
+ // Module metadata if this is a module compile.
+ RefPtr<StencilModuleMetadata> moduleMetadata;
+
+ // AsmJS modules generated by parsing. These scripts are never lazy and
+ // therefore only generated during initial parse.
+ RefPtr<StencilAsmJSContainer> asmJS;
+
+ // End of fields.
+
+ // Construct a CompilationStencil
+ explicit CompilationStencil(ScriptSource* source)
+ : alloc(LifoAllocChunkSize), source(source) {}
+
+ // Take the ownership of on-heap ExtensibleCompilationStencil and
+ // borrow from it.
+ explicit CompilationStencil(
+ UniquePtr<ExtensibleCompilationStencil>&& extensibleStencil);
+
+ protected:
+ void borrowFromExtensibleCompilationStencil(
+ ExtensibleCompilationStencil& extensibleStencil);
+
+#ifdef DEBUG
+ void assertBorrowingFromExtensibleCompilationStencil(
+ const ExtensibleCompilationStencil& extensibleStencil) const;
+#endif
+
+ public:
+ bool isInitialStencil() const {
+ return functionKey == SourceExtent::NullFunctionKey;
+ }
+
+ [[nodiscard]] static bool instantiateStencilAfterPreparation(
+ JSContext* cx, CompilationInput& input, const CompilationStencil& stencil,
+ CompilationGCOutput& gcOutput);
+
+ [[nodiscard]] static bool prepareForInstantiate(
+ FrontendContext* fc, CompilationAtomCache& atomCache,
+ const CompilationStencil& stencil, CompilationGCOutput& gcOutput);
+ [[nodiscard]] static bool prepareForInstantiate(
+ FrontendContext* fc, const CompilationStencil& stencil,
+ PreallocatedCompilationGCOutput& gcOutput);
+
+ [[nodiscard]] static bool instantiateStencils(
+ JSContext* cx, CompilationInput& input, const CompilationStencil& stencil,
+ CompilationGCOutput& gcOutput);
+
+ // Decode the special self-hosted stencil
+ [[nodiscard]] bool instantiateSelfHostedAtoms(
+ JSContext* cx, AtomSet& atomSet, CompilationAtomCache& atomCache) const;
+ [[nodiscard]] JSScript* instantiateSelfHostedTopLevelForRealm(
+ JSContext* cx, CompilationInput& input);
+ [[nodiscard]] JSFunction* instantiateSelfHostedLazyFunction(
+ JSContext* cx, CompilationAtomCache& atomCache, ScriptIndex index,
+ JS::Handle<JSAtom*> name);
+ [[nodiscard]] bool delazifySelfHostedFunction(JSContext* cx,
+ CompilationAtomCache& atomCache,
+ ScriptIndexRange range,
+ JS::Handle<JSFunction*> fun);
+
+ [[nodiscard]] bool serializeStencils(JSContext* cx, CompilationInput& input,
+ JS::TranscodeBuffer& buf,
+ bool* succeededOut = nullptr) const;
+ [[nodiscard]] bool deserializeStencils(
+ FrontendContext* fc, const JS::ReadOnlyCompileOptions& options,
+ const JS::TranscodeRange& range, bool* succeededOut = nullptr);
+
+ // To avoid any misuses, make sure this is neither copyable or assignable.
+ CompilationStencil(const CompilationStencil&) = delete;
+ CompilationStencil(CompilationStencil&&) = delete;
+ CompilationStencil& operator=(const CompilationStencil&) = delete;
+ CompilationStencil& operator=(CompilationStencil&&) = delete;
+#ifdef DEBUG
+ ~CompilationStencil() {
+ // We can mix UniquePtr<..> and RefPtr<..>. This asserts that a UniquePtr
+ // does not delete a reference-counted stencil.
+ MOZ_ASSERT(!refCount);
+ }
+#endif
+
+ static inline ScriptStencilIterable functionScriptStencils(
+ const CompilationStencil& stencil, CompilationGCOutput& gcOutput);
+
+ void setFunctionKey(BaseScript* lazy) {
+ functionKey = lazy->extent().toFunctionKey();
+ }
+
+ inline size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
+ size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return mallocSizeOf(this) + sizeOfExcludingThis(mallocSizeOf);
+ }
+
+ const ParserAtomSpan& parserAtomsSpan() const { return parserAtomData; }
+
+ bool isModule() const;
+
+ bool hasMultipleReference() const { return refCount > 1; }
+
+ bool hasOwnedBorrow() const {
+ return storageType == StorageType::OwnedExtensible;
+ }
+
+ ExtensibleCompilationStencil* takeOwnedBorrow() {
+ MOZ_ASSERT(!hasMultipleReference());
+ MOZ_ASSERT(hasOwnedBorrow());
+ return ownedBorrowStencil.release();
+ }
+
+#ifdef DEBUG
+ void assertNoExternalDependency() const;
+#endif
+
+#if defined(DEBUG) || defined(JS_JITSPEW)
+ void dump() const;
+ void dump(js::JSONPrinter& json) const;
+ void dumpFields(js::JSONPrinter& json) const;
+
+ void dumpAtom(TaggedParserAtomIndex index) const;
+#endif
+};
+
+// The top level struct of stencil specialized for extensible case.
+// Used as the temporary storage during compilation, an the compilation output.
+//
+// All not-owning pointer fields point the internal LifoAlloc.
+//
+// See CompilationStencil for each field's description.
+//
+// Also see SMDOC in Stencil.h for more info.
+struct ExtensibleCompilationStencil {
+ bool canLazilyParse = false;
+
+ using FunctionKey = SourceExtent::FunctionKey;
+
+ FunctionKey functionKey = SourceExtent::NullFunctionKey;
+
+ // Data pointed by other fields are allocated in this LifoAlloc,
+ // and moved to `CompilationStencil.alloc`.
+ LifoAlloc alloc;
+
+ RefPtr<ScriptSource> source;
+
+ // NOTE: We reserve a modest amount of inline storage in order to reduce
+ // allocations in the most common delazification cases. These common
+ // cases have one script and scope, as well as a handful of gcthings.
+ // For complex pages this covers about 75% of delazifications.
+
+ Vector<ScriptStencil, 1, js::SystemAllocPolicy> scriptData;
+ Vector<ScriptStencilExtra, 0, js::SystemAllocPolicy> scriptExtra;
+
+ Vector<TaggedScriptThingIndex, 8, js::SystemAllocPolicy> gcThingData;
+
+ Vector<ScopeStencil, 1, js::SystemAllocPolicy> scopeData;
+ Vector<BaseParserScopeData*, 1, js::SystemAllocPolicy> scopeNames;
+
+ Vector<RegExpStencil, 0, js::SystemAllocPolicy> regExpData;
+ Vector<BigIntStencil, 0, js::SystemAllocPolicy> bigIntData;
+ Vector<ObjLiteralStencil, 0, js::SystemAllocPolicy> objLiteralData;
+
+ // Table of parser atoms for this compilation.
+ ParserAtomsTable parserAtoms;
+
+ SharedDataContainer sharedData;
+
+ RefPtr<StencilModuleMetadata> moduleMetadata;
+
+ RefPtr<StencilAsmJSContainer> asmJS;
+
+ explicit ExtensibleCompilationStencil(ScriptSource* source);
+
+ explicit ExtensibleCompilationStencil(CompilationInput& input);
+ ExtensibleCompilationStencil(const JS::ReadOnlyCompileOptions& options,
+ RefPtr<ScriptSource> source);
+
+ ExtensibleCompilationStencil(ExtensibleCompilationStencil&& other) noexcept
+ : canLazilyParse(other.canLazilyParse),
+ functionKey(other.functionKey),
+ alloc(CompilationStencil::LifoAllocChunkSize),
+ source(std::move(other.source)),
+ scriptData(std::move(other.scriptData)),
+ scriptExtra(std::move(other.scriptExtra)),
+ gcThingData(std::move(other.gcThingData)),
+ scopeData(std::move(other.scopeData)),
+ scopeNames(std::move(other.scopeNames)),
+ regExpData(std::move(other.regExpData)),
+ bigIntData(std::move(other.bigIntData)),
+ objLiteralData(std::move(other.objLiteralData)),
+ parserAtoms(std::move(other.parserAtoms)),
+ sharedData(std::move(other.sharedData)),
+ moduleMetadata(std::move(other.moduleMetadata)),
+ asmJS(std::move(other.asmJS)) {
+ alloc.steal(&other.alloc);
+ parserAtoms.fixupAlloc(alloc);
+ }
+
+ ExtensibleCompilationStencil& operator=(
+ ExtensibleCompilationStencil&& other) noexcept {
+ MOZ_ASSERT(alloc.isEmpty());
+
+ canLazilyParse = other.canLazilyParse;
+ functionKey = other.functionKey;
+ source = std::move(other.source);
+ scriptData = std::move(other.scriptData);
+ scriptExtra = std::move(other.scriptExtra);
+ gcThingData = std::move(other.gcThingData);
+ scopeData = std::move(other.scopeData);
+ scopeNames = std::move(other.scopeNames);
+ regExpData = std::move(other.regExpData);
+ bigIntData = std::move(other.bigIntData);
+ objLiteralData = std::move(other.objLiteralData);
+ parserAtoms = std::move(other.parserAtoms);
+ sharedData = std::move(other.sharedData);
+ moduleMetadata = std::move(other.moduleMetadata);
+ asmJS = std::move(other.asmJS);
+
+ alloc.steal(&other.alloc);
+ parserAtoms.fixupAlloc(alloc);
+
+ return *this;
+ }
+
+ void setFunctionKey(const SourceExtent& extent) {
+ functionKey = extent.toFunctionKey();
+ }
+
+ bool isInitialStencil() const {
+ return functionKey == SourceExtent::NullFunctionKey;
+ }
+
+ // Steal CompilationStencil content.
+ [[nodiscard]] bool steal(FrontendContext* fc,
+ RefPtr<CompilationStencil>&& other);
+
+ // Clone ExtensibleCompilationStencil content.
+ [[nodiscard]] bool cloneFrom(FrontendContext* fc,
+ const CompilationStencil& other);
+ [[nodiscard]] bool cloneFrom(FrontendContext* fc,
+ const ExtensibleCompilationStencil& other);
+
+ private:
+ template <typename Stencil>
+ [[nodiscard]] bool cloneFromImpl(FrontendContext* fc, const Stencil& other);
+
+ public:
+ const ParserAtomVector& parserAtomsSpan() const {
+ return parserAtoms.entries();
+ }
+
+ bool isModule() const;
+
+ inline size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const;
+ size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return mallocSizeOf(this) + sizeOfExcludingThis(mallocSizeOf);
+ }
+
+#ifdef DEBUG
+ void assertNoExternalDependency() const;
+#endif
+
+#if defined(DEBUG) || defined(JS_JITSPEW)
+ void dump();
+ void dump(js::JSONPrinter& json);
+ void dumpFields(js::JSONPrinter& json);
+
+ void dumpAtom(TaggedParserAtomIndex index);
+#endif
+};
+
+// The internal state of the compilation.
+struct MOZ_RAII CompilationState : public ExtensibleCompilationStencil {
+ Directives directives;
+
+ ScopeContext scopeContext;
+
+ UsedNameTracker usedNames;
+
+ // LifoAlloc scope used by Parser for allocating AST etc.
+ //
+ // NOTE: This is not used for ExtensibleCompilationStencil.alloc.
+ LifoAllocScope& parserAllocScope;
+
+ CompilationInput& input;
+ CompilationSyntaxParseCache previousParseCache;
+
+ // The number of functions that *will* have bytecode.
+ // This doesn't count top-level non-function script.
+ //
+ // This should be counted while parsing, and should be passed to
+ // SharedDataContainer.prepareStorageFor *before* start emitting bytecode.
+ size_t nonLazyFunctionCount = 0;
+
+ // End of fields.
+
+ CompilationState(FrontendContext* fc, LifoAllocScope& parserAllocScope,
+ CompilationInput& input);
+
+ bool init(FrontendContext* fc, ScopeBindingCache* scopeCache,
+ InheritThis inheritThis = InheritThis::No,
+ JSObject* enclosingEnv = nullptr) {
+ if (!scopeContext.init(fc, input, parserAtoms, scopeCache, inheritThis,
+ enclosingEnv)) {
+ return false;
+ }
+
+ // gcThings is later used by the full parser initialization.
+ if (input.isDelazifying()) {
+ InputScript lazy = input.lazyOuterScript();
+ auto& atomCache = input.atomCache;
+ if (!previousParseCache.init(fc, alloc, parserAtoms, atomCache, lazy)) {
+ return false;
+ }
+ }
+
+ return true;
+ }
+
+ // Track the state of key allocations and roll them back as parts of parsing
+ // get retried. This ensures iteration during stencil instantiation does not
+ // encounter discarded frontend state.
+ struct CompilationStatePosition {
+ // Temporarily share this token struct with CompilationState.
+ size_t scriptDataLength = 0;
+
+ size_t asmJSCount = 0;
+ };
+
+ bool prepareSharedDataStorage(FrontendContext* fc);
+
+ CompilationStatePosition getPosition();
+ void rewind(const CompilationStatePosition& pos);
+
+ // When parsing arrow function, parameter is parsed twice, and if there are
+ // functions inside parameter expression, stencils will be created for them.
+ //
+ // Those functions exist only for lazy parsing.
+ // Mark them "ghost", so that they don't affect other parts.
+ //
+ // See GHOST_FUNCTION in FunctionFlags.h for more details.
+ void markGhost(const CompilationStatePosition& pos);
+
+ // Allocate space for `length` gcthings, and return the address of the
+ // first element to `cursor` to initialize on the caller.
+ bool allocateGCThingsUninitialized(FrontendContext* fc,
+ ScriptIndex scriptIndex, size_t length,
+ TaggedScriptThingIndex** cursor);
+
+ bool appendScriptStencilAndData(FrontendContext* fc);
+
+ bool appendGCThings(FrontendContext* fc, ScriptIndex scriptIndex,
+ mozilla::Span<const TaggedScriptThingIndex> things);
+};
+
+// A temporary CompilationStencil instance that borrows
+// ExtensibleCompilationStencil data.
+// Ensure that this instance does not outlive the ExtensibleCompilationStencil.
+class MOZ_STACK_CLASS BorrowingCompilationStencil : public CompilationStencil {
+ public:
+ explicit BorrowingCompilationStencil(
+ ExtensibleCompilationStencil& extensibleStencil);
+};
+
+// Size of dynamic data. Ignores Spans (unless their contents are in the
+// LifoAlloc) and RefPtrs since we are not the unique owner.
+inline size_t CompilationStencil::sizeOfExcludingThis(
+ mozilla::MallocSizeOf mallocSizeOf) const {
+ if (ownedBorrowStencil) {
+ return ownedBorrowStencil->sizeOfIncludingThis(mallocSizeOf);
+ }
+
+ size_t moduleMetadataSize =
+ moduleMetadata ? moduleMetadata->sizeOfIncludingThis(mallocSizeOf) : 0;
+ size_t asmJSSize = asmJS ? asmJS->sizeOfIncludingThis(mallocSizeOf) : 0;
+
+ return alloc.sizeOfExcludingThis(mallocSizeOf) +
+ sharedData.sizeOfExcludingThis(mallocSizeOf) + moduleMetadataSize +
+ asmJSSize;
+}
+
+inline size_t ExtensibleCompilationStencil::sizeOfExcludingThis(
+ mozilla::MallocSizeOf mallocSizeOf) const {
+ size_t moduleMetadataSize =
+ moduleMetadata ? moduleMetadata->sizeOfIncludingThis(mallocSizeOf) : 0;
+ size_t asmJSSize = asmJS ? asmJS->sizeOfIncludingThis(mallocSizeOf) : 0;
+
+ return alloc.sizeOfExcludingThis(mallocSizeOf) +
+ scriptData.sizeOfExcludingThis(mallocSizeOf) +
+ scriptExtra.sizeOfExcludingThis(mallocSizeOf) +
+ gcThingData.sizeOfExcludingThis(mallocSizeOf) +
+ scopeData.sizeOfExcludingThis(mallocSizeOf) +
+ scopeNames.sizeOfExcludingThis(mallocSizeOf) +
+ regExpData.sizeOfExcludingThis(mallocSizeOf) +
+ bigIntData.sizeOfExcludingThis(mallocSizeOf) +
+ objLiteralData.sizeOfExcludingThis(mallocSizeOf) +
+ parserAtoms.sizeOfExcludingThis(mallocSizeOf) +
+ sharedData.sizeOfExcludingThis(mallocSizeOf) + moduleMetadataSize +
+ asmJSSize;
+}
+
+// A PreAllocateableGCArray is an array of GC thing pointers.
+//
+// The array's internal buffer can be allocated ahead of time, possibly off
+// main thread.
+template <typename T>
+struct PreAllocateableGCArray {
+ private:
+ size_t length_ = 0;
+
+ // Inline element for the case when length_ == 1.
+ T inlineElem_;
+
+ // Heap-allocated elements for the case when length_ > 1;
+ T* elems_ = nullptr;
+
+ public:
+ struct Preallocated {
+ private:
+ size_t length_ = 0;
+ uintptr_t* elems_ = nullptr;
+
+ friend struct PreAllocateableGCArray<T>;
+
+ public:
+ Preallocated() = default;
+ ~Preallocated();
+
+ bool empty() const { return length_ == 0; }
+
+ size_t length() const { return length_; }
+
+ private:
+ bool isInline() const { return length_ == 1; }
+
+ public:
+ bool allocate(size_t length);
+
+ size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return sizeof(uintptr_t) * length_;
+ }
+ };
+
+ PreAllocateableGCArray() {
+ static_assert(std::is_pointer_v<T>,
+ "PreAllocateableGCArray element must be a pointer");
+ }
+ ~PreAllocateableGCArray();
+
+ bool empty() const { return length_ == 0; }
+
+ size_t length() const { return length_; }
+
+ private:
+ bool isInline() const { return length_ == 1; }
+
+ public:
+ bool allocate(size_t length);
+ bool allocateWith(T init, size_t length);
+
+ // Steal pre-allocated buffer.
+ void steal(Preallocated&& buffer);
+
+ T& operator[](size_t index) {
+ MOZ_ASSERT(index < length_);
+
+ if (isInline()) {
+ return inlineElem_;
+ }
+
+ return elems_[index];
+ }
+ const T& operator[](size_t index) const {
+ MOZ_ASSERT(index < length_);
+
+ if (isInline()) {
+ return inlineElem_;
+ }
+
+ return elems_[index];
+ }
+
+ size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ if (!elems_) {
+ return 0;
+ }
+
+ return sizeof(T) * length_;
+ }
+
+ void trace(JSTracer* trc);
+};
+
+struct CompilationGCOutput;
+
+// Pre-allocated storage for CompilationGCOutput.
+struct PreallocatedCompilationGCOutput {
+ private:
+ PreAllocateableGCArray<JSFunction*>::Preallocated functions;
+ PreAllocateableGCArray<js::Scope*>::Preallocated scopes;
+
+ friend struct CompilationGCOutput;
+
+ public:
+ PreallocatedCompilationGCOutput() = default;
+
+ [[nodiscard]] bool allocate(FrontendContext* fc, size_t scriptDataLength,
+ size_t scopeDataLength) {
+ if (!functions.allocate(scriptDataLength)) {
+ ReportOutOfMemory(fc);
+ return false;
+ }
+ if (!scopes.allocate(scopeDataLength)) {
+ ReportOutOfMemory(fc);
+ return false;
+ }
+ return true;
+ }
+
+ size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return functions.sizeOfExcludingThis(mallocSizeOf) +
+ scopes.sizeOfExcludingThis(mallocSizeOf);
+ }
+};
+
+// The output of GC allocation from stencil.
+struct CompilationGCOutput {
+ // The resulting outermost script for the compilation powered
+ // by this CompilationStencil.
+ JSScript* script = nullptr;
+
+ // The resulting module object if there is one.
+ ModuleObject* module = nullptr;
+
+ // An array to handle tracing of JSFunction* and Atoms within.
+ //
+ // If the top level script isn't a function, the item at TopLevelIndex is
+ // nullptr.
+ PreAllocateableGCArray<JSFunction*> functions;
+
+ // References to scopes are controlled via AbstractScopePtr, which holds onto
+ // an index (and CompilationStencil reference).
+ PreAllocateableGCArray<js::Scope*> scopes;
+
+ // The result ScriptSourceObject. This is unused in delazifying parses.
+ ScriptSourceObject* sourceObject = nullptr;
+
+ private:
+ // If we are only instantiating part of a stencil, we can reduce allocations
+ // by setting a base index and allocating only the array elements we need.
+ // This applies to both the `functions` and `scopes` arrays. These fields are
+ // initialized by `ensureAllocatedWithBaseIndex` which also allocates the
+ // array appropriately.
+ //
+ // Note: These are only used for self-hosted delazification currently.
+ ScriptIndex functionsBaseIndex{};
+ ScopeIndex scopesBaseIndex{};
+
+ // End of fields.
+
+ public:
+ CompilationGCOutput() = default;
+
+ // Helper to access the `functions` array. The NoBaseIndex version is used if
+ // the caller never uses a base index.
+ JSFunction*& getFunction(ScriptIndex index) {
+ return functions[index - functionsBaseIndex];
+ }
+ JSFunction*& getFunctionNoBaseIndex(ScriptIndex index) {
+ MOZ_ASSERT(!functionsBaseIndex);
+ return functions[index];
+ }
+
+ // Helper accessors for the `scopes` array.
+ js::Scope*& getScope(ScopeIndex index) {
+ return scopes[index - scopesBaseIndex];
+ }
+ js::Scope*& getScopeNoBaseIndex(ScopeIndex index) {
+ MOZ_ASSERT(!scopesBaseIndex);
+ return scopes[index];
+ }
+ js::Scope* getScopeNoBaseIndex(ScopeIndex index) const {
+ MOZ_ASSERT(!scopesBaseIndex);
+ return scopes[index];
+ }
+
+ // Allocate output arrays.
+ [[nodiscard]] bool ensureAllocated(FrontendContext* fc,
+ size_t scriptDataLength,
+ size_t scopeDataLength) {
+ if (functions.empty()) {
+ if (!functions.allocate(scriptDataLength)) {
+ ReportOutOfMemory(fc);
+ return false;
+ }
+ }
+ if (scopes.empty()) {
+ if (!scopes.allocate(scopeDataLength)) {
+ ReportOutOfMemory(fc);
+ return false;
+ }
+ }
+ return true;
+ }
+
+ // Steal output arrays' buffer.
+ void steal(PreallocatedCompilationGCOutput&& pre) {
+ functions.steal(std::move(pre.functions));
+ scopes.steal(std::move(pre.scopes));
+ }
+
+ // A variant of `ensureAllocated` that sets a base index for the function and
+ // scope arrays. This is used when instantiating only a subset of the stencil.
+ // Currently this only applies to self-hosted delazification. The ranges
+ // include the start index and exclude the limit index.
+ [[nodiscard]] bool ensureAllocatedWithBaseIndex(FrontendContext* fc,
+ ScriptIndex scriptStart,
+ ScriptIndex scriptLimit,
+ ScopeIndex scopeStart,
+ ScopeIndex scopeLimit) {
+ this->functionsBaseIndex = scriptStart;
+ this->scopesBaseIndex = scopeStart;
+
+ return ensureAllocated(fc, scriptLimit - scriptStart,
+ scopeLimit - scopeStart);
+ }
+
+ // Size of dynamic data. Note that GC data is counted by GC and not here.
+ size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return functions.sizeOfExcludingThis(mallocSizeOf) +
+ scopes.sizeOfExcludingThis(mallocSizeOf);
+ }
+
+ void trace(JSTracer* trc);
+};
+
+// Iterator over functions that make up a CompilationStencil. This abstracts
+// over the parallel arrays in stencil and gc-output that use the same index
+// system.
+class ScriptStencilIterable {
+ public:
+ class ScriptAndFunction {
+ public:
+ const ScriptStencil& script;
+ const ScriptStencilExtra* scriptExtra;
+ JSFunction* function;
+ ScriptIndex index;
+
+ ScriptAndFunction() = delete;
+ ScriptAndFunction(const ScriptStencil& script,
+ const ScriptStencilExtra* scriptExtra,
+ JSFunction* function, ScriptIndex index)
+ : script(script),
+ scriptExtra(scriptExtra),
+ function(function),
+ index(index) {}
+ };
+
+ class Iterator {
+ size_t index_ = 0;
+ const CompilationStencil& stencil_;
+ CompilationGCOutput& gcOutput_;
+
+ Iterator(const CompilationStencil& stencil, CompilationGCOutput& gcOutput,
+ size_t index)
+ : index_(index), stencil_(stencil), gcOutput_(gcOutput) {
+ MOZ_ASSERT(index == stencil.scriptData.size());
+ }
+
+ public:
+ explicit Iterator(const CompilationStencil& stencil,
+ CompilationGCOutput& gcOutput)
+ : stencil_(stencil), gcOutput_(gcOutput) {
+ skipTopLevelNonFunction();
+ }
+
+ Iterator operator++() {
+ next();
+ assertFunction();
+ return *this;
+ }
+
+ void next() {
+ MOZ_ASSERT(index_ < stencil_.scriptData.size());
+ index_++;
+ }
+
+ void assertFunction() {
+ if (index_ < stencil_.scriptData.size()) {
+ MOZ_ASSERT(stencil_.scriptData[index_].isFunction());
+ }
+ }
+
+ void skipTopLevelNonFunction() {
+ MOZ_ASSERT(index_ == 0);
+ if (stencil_.scriptData.size()) {
+ if (!stencil_.scriptData[0].isFunction()) {
+ next();
+ assertFunction();
+ }
+ }
+ }
+
+ bool operator!=(const Iterator& other) const {
+ return index_ != other.index_;
+ }
+
+ ScriptAndFunction operator*() {
+ ScriptIndex index = ScriptIndex(index_);
+ const ScriptStencil& script = stencil_.scriptData[index];
+ const ScriptStencilExtra* scriptExtra = nullptr;
+ if (stencil_.isInitialStencil()) {
+ scriptExtra = &stencil_.scriptExtra[index];
+ }
+ return ScriptAndFunction(script, scriptExtra,
+ gcOutput_.getFunctionNoBaseIndex(index), index);
+ }
+
+ static Iterator end(const CompilationStencil& stencil,
+ CompilationGCOutput& gcOutput) {
+ return Iterator(stencil, gcOutput, stencil.scriptData.size());
+ }
+ };
+
+ const CompilationStencil& stencil_;
+ CompilationGCOutput& gcOutput_;
+
+ explicit ScriptStencilIterable(const CompilationStencil& stencil,
+ CompilationGCOutput& gcOutput)
+ : stencil_(stencil), gcOutput_(gcOutput) {}
+
+ Iterator begin() const { return Iterator(stencil_, gcOutput_); }
+
+ Iterator end() const { return Iterator::end(stencil_, gcOutput_); }
+};
+
+inline ScriptStencilIterable CompilationStencil::functionScriptStencils(
+ const CompilationStencil& stencil, CompilationGCOutput& gcOutput) {
+ return ScriptStencilIterable(stencil, gcOutput);
+}
+
+// Merge CompilationStencil for delazification into initial
+// ExtensibleCompilationStencil.
+struct CompilationStencilMerger {
+ private:
+ using FunctionKey = SourceExtent::FunctionKey;
+
+ // The stencil for the initial compilation.
+ // Delazifications are merged into this.
+ //
+ // If any failure happens during merge operation, this field is reset to
+ // nullptr.
+ UniquePtr<ExtensibleCompilationStencil> initial_;
+
+ // A Map from function key to the ScriptIndex in the initial stencil.
+ using FunctionKeyToScriptIndexMap =
+ mozilla::HashMap<FunctionKey, ScriptIndex,
+ mozilla::DefaultHasher<FunctionKey>,
+ js::SystemAllocPolicy>;
+ FunctionKeyToScriptIndexMap functionKeyToInitialScriptIndex_;
+
+ [[nodiscard]] bool buildFunctionKeyToIndex(FrontendContext* fc);
+
+ ScriptIndex getInitialScriptIndexFor(
+ const CompilationStencil& delazification) const;
+
+ // A map from delazification's ParserAtomIndex to
+ // initial's TaggedParserAtomIndex
+ using AtomIndexMap = Vector<TaggedParserAtomIndex, 0, js::SystemAllocPolicy>;
+
+ [[nodiscard]] bool buildAtomIndexMap(FrontendContext* fc,
+ const CompilationStencil& delazification,
+ AtomIndexMap& atomIndexMap);
+
+ public:
+ CompilationStencilMerger() = default;
+
+ // Set the initial stencil and prepare for merging.
+ [[nodiscard]] bool setInitial(
+ FrontendContext* fc, UniquePtr<ExtensibleCompilationStencil>&& initial);
+
+ // Merge the delazification stencil into the initial stencil.
+ [[nodiscard]] bool addDelazification(
+ FrontendContext* fc, const CompilationStencil& delazification);
+
+ ExtensibleCompilationStencil& getResult() const { return *initial_; }
+ UniquePtr<ExtensibleCompilationStencil> takeResult() {
+ return std::move(initial_);
+ }
+};
+
+const ScopeStencil& ScopeStencilRef::scope() const {
+ return context_.scopeData[scopeIndex_];
+}
+
+InputScope InputScope::enclosing() const {
+ return scope_.match(
+ [](const Scope* ptr) {
+ // This may return a nullptr Scope pointer.
+ return InputScope(ptr->enclosing());
+ },
+ [](const ScopeStencilRef& ref) {
+ if (ref.scope().hasEnclosing()) {
+ return InputScope(ref.context_, ref.scope().enclosing());
+ }
+ // The global scope is not known by the Stencil, while parsing inner
+ // functions from Stencils where they are known at the execution using
+ // the GlobalScope.
+ if (ref.scope().kind() == ScopeKind::Module) {
+ return InputScope(FakeStencilGlobalScope{});
+ }
+ return InputScope(nullptr);
+ },
+ [](const FakeStencilGlobalScope&) { return InputScope(nullptr); });
+}
+
+FunctionFlags InputScope::functionFlags() const {
+ return scope_.match(
+ [](const Scope* ptr) {
+ JSFunction* fun = ptr->as<FunctionScope>().canonicalFunction();
+ return fun->flags();
+ },
+ [](const ScopeStencilRef& ref) {
+ MOZ_ASSERT(ref.scope().isFunction());
+ ScriptIndex scriptIndex = ref.scope().functionIndex();
+ ScriptStencil& data = ref.context_.scriptData[scriptIndex];
+ return data.functionFlags;
+ },
+ [](const FakeStencilGlobalScope&) -> FunctionFlags {
+ MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("No functionFlags on global.");
+ });
+}
+
+ImmutableScriptFlags InputScope::immutableFlags() const {
+ return scope_.match(
+ [](const Scope* ptr) {
+ JSFunction* fun = ptr->as<FunctionScope>().canonicalFunction();
+ return fun->baseScript()->immutableFlags();
+ },
+ [](const ScopeStencilRef& ref) {
+ MOZ_ASSERT(ref.scope().isFunction());
+ ScriptIndex scriptIndex = ref.scope().functionIndex();
+ ScriptStencilExtra& extra = ref.context_.scriptExtra[scriptIndex];
+ return extra.immutableFlags;
+ },
+ [](const FakeStencilGlobalScope&) -> ImmutableScriptFlags {
+ MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE("No immutableFlags on global.");
+ });
+}
+
+MemberInitializers InputScope::getMemberInitializers() const {
+ return scope_.match(
+ [](const Scope* ptr) {
+ JSFunction* fun = ptr->as<FunctionScope>().canonicalFunction();
+ return fun->baseScript()->getMemberInitializers();
+ },
+ [](const ScopeStencilRef& ref) {
+ MOZ_ASSERT(ref.scope().isFunction());
+ ScriptIndex scriptIndex = ref.scope().functionIndex();
+ ScriptStencilExtra& extra = ref.context_.scriptExtra[scriptIndex];
+ return extra.memberInitializers();
+ },
+ [](const FakeStencilGlobalScope&) -> MemberInitializers {
+ MOZ_MAKE_COMPILER_ASSUME_IS_UNREACHABLE(
+ "No getMemberInitializers on global.");
+ });
+}
+
+const ScriptStencil& ScriptStencilRef::scriptData() const {
+ return context_.scriptData[scriptIndex_];
+}
+
+const ScriptStencilExtra& ScriptStencilRef::scriptExtra() const {
+ return context_.scriptExtra[scriptIndex_];
+}
+
+} // namespace frontend
+} // namespace js
+
+#endif // frontend_CompilationStencil_h