Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 346 insertions, 0 deletions

diff --git a/js/src/vm/StencilEnums.h b/js/src/vm/StencilEnums.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 vm_StencilEnums_h
+#define vm_StencilEnums_h
+
+#include <stdint.h>  // uint8_t
+
+//
+// Enum definitions shared between frontend, stencil, and the VM.
+//
+
+namespace js {
+
+// [SMDOC] Try Notes
+//
+// Trynotes are attached to regions that are involved with
+// exception unwinding. They can be broken up into four categories:
+//
+// 1. Catch and Finally: Basic exception handling. A Catch trynote
+//    covers the range of the associated try. A Finally trynote covers
+//    the try and the catch.
+//
+// 2. ForIn and Destructuring: These operations create an iterator
+//    which must be cleaned up (by calling IteratorClose) during
+//    exception unwinding.
+//
+// 3. ForOf and ForOfIterclose: For-of loops handle unwinding using
+//    catch blocks. These trynotes are used for for-of breaks/returns,
+//    which create regions that are lexically within a for-of block,
+//    but logically outside of it. See TryNoteIter::settle for more
+//    details.
+//
+// 4. Loop: This represents normal for/while/do-while loops. It is
+//    unnecessary for exception unwinding, but storing the boundaries
+//    of loops here is helpful for heuristics that need to know
+//    whether a given op is inside a loop.
+enum class TryNoteKind : uint8_t {
+  Catch,
+  Finally,
+  ForIn,
+  Destructuring,
+  ForOf,
+  ForOfIterClose,
+  Loop
+};
+
+// [SMDOC] Script Flags
+//
+// Interpreted scripts represented by the BaseScript type use two flag words to
+// encode an assortment of conditions and attributes about the script.
+//
+// The "immutable" flags are a combination of input flags describing aspects of
+// the execution context that affect parsing (such as if we are an ES module or
+// normal script), and flags derived from source text. These flags are preserved
+// during cloning and serializing. As well, they should never change after the
+// BaseScript is created (although there are currently a few exceptions for
+// de-/re-lazification that remain).
+//
+// The "mutable" flags are temporary flags that are used by subsystems in the
+// engine such as the debugger or JITs. These flags are not preserved through
+// serialization or cloning since the attributes are generally associated with
+// one specific instance of a BaseScript.
+
+enum class ImmutableScriptFlagsEnum : uint32_t {
+  // Input Flags
+  //
+  // These flags are from CompileOptions or the Parser entry point. They
+  // generally cannot be derived from the source text alone.
+  // ----
+
+  // A script may have one of the following kinds: Global, Eval, Module,
+  // Function. At most one flag can be set, with a default of Global.
+  IsForEval = 1 << 0,
+  IsModule = 1 << 1,
+  IsFunction = 1 << 2,
+
+  // The script is compiled as engine-internal self-hosted JavaScript. This mode
+  // is used to implement certain library functions and has special parse,
+  // bytecode, and runtime behaviour that differs from normal script.
+  SelfHosted = 1 << 3,
+
+  // The script was compiled with the default mode set to strict mode. Note that
+  // this tracks the default value, while the actual mode used (after processing
+  // source and its directives) is the `Strict` flag below.
+  ForceStrict = 1 << 4,
+
+  // The script has a non-syntactic scope on its environment chain. That is,
+  // there may be objects about which we know nothing between the outermost
+  // syntactic scope and the global.
+  HasNonSyntacticScope = 1 << 5,
+
+  // The script return value will not be used and simplified code will be
+  // generated. This can only be applied to top-level scripts. The value this
+  // script returns will be UndefinedValue instead of what the spec normally
+  // prescribes.
+  NoScriptRval = 1 << 6,
+
+  // TreatAsRunOnce roughly indicates that a script is expected to be run no
+  // more than once. This affects optimizations and heuristics.
+  //
+  // On top-level global/eval/module scripts, this is set when the embedding
+  // ensures this script will not be re-used. In this case, parser literals may
+  // be exposed directly instead of being cloned.
+  TreatAsRunOnce = 1 << 7,
+  // ----
+
+  // Parser Flags
+  //
+  // Flags computed by the Parser from the source text and input flags.
+  // ----
+
+  // Generated code will execute in strict mode. This is due to either the
+  // ForceStrict flag being specified above, or due to source text itself (such
+  // as "use strict" directives).
+  Strict = 1 << 8,
+
+  // Script is parsed with a top-level goal of Module. This may be a top-level
+  // or an inner-function script.
+  HasModuleGoal = 1 << 9,
+
+  // Script contains inner functions.
+  //
+  // Note: This prevents relazification since inner function close-over the
+  // current scripts scopes.
+  HasInnerFunctions = 1 << 10,
+
+  // There is a direct eval statement in this script OR in any of its inner
+  // functions.
+  //
+  // Note: This prevents relazification since it can introduce inner functions.
+  HasDirectEval = 1 << 11,
+
+  // The (static) bindings of this script must support dynamic name access for
+  // read/write. The environment chain is used to do these dynamic lookups and
+  // optimizations to avoid allocating environments are suppressed.
+  //
+  // This includes direct-eval, `with`, and `delete` in this script OR in any of
+  // its inner functions.
+  //
+  // Note: Access through the arguments object is not considered dynamic binding
+  // access since it does not go through the normal name lookup mechanism.
+  BindingsAccessedDynamically = 1 << 12,
+
+  // A tagged template exists in the body (which will use JSOp::CallSiteObj in
+  // bytecode).
+  //
+  // Note: This prevents relazification since the template's object is
+  // observable to the user and cannot be recreated.
+  HasCallSiteObj = 1 << 13,
+
+  // Parser Flags for Functions
+  // ----
+
+  // This function's initial prototype is one of Function, GeneratorFunction,
+  // AsyncFunction, or AsyncGeneratorFunction as indicated by these flags.
+  //
+  // If either of these flags is set, the script may suspend and resume as it
+  // executes. Stack frames for this script also have a generator object.
+  IsAsync = 1 << 14,
+  IsGenerator = 1 << 15,
+
+  // This function's body serves as the `var` environment for a non-strict
+  // direct eval. This matters because it's the only way bindings can be
+  // dynamically added to a local environment, possibly shadowing other
+  // variables.
+  FunHasExtensibleScope = 1 << 16,
+
+  // This function has an internal .this binding and we need to emit
+  // JSOp::FunctionThis in the prologue to initialize it. This binding may be
+  // used directly for "this", or indirectly (such as class constructors).
+  FunctionHasThisBinding = 1 << 17,
+
+  // This function is a class method that must uses an internal [[HomeObject]]
+  // slot. This slot is initialized when the class definition is executed in the
+  // enclosing function.
+  NeedsHomeObject = 1 << 18,
+
+  // This function is a constructor for a derived class. This is a class that
+  // uses the `extends` syntax.
+  IsDerivedClassConstructor = 1 << 19,
+
+  // This function is synthesized by the Parser. This is used for field
+  // initializer lambdas and missing constructors for classes. These functions
+  // have unusual source coordinates and may be hidden from things like
+  // Reflect.parse.
+  IsSyntheticFunction = 1 << 20,
+
+  // This function is a class constructor that has MemberInitializer data
+  // associated with it.
+  UseMemberInitializers = 1 << 21,
+
+  // This function has a rest (`...`) parameter.
+  HasRest = 1 << 22,
+
+  // This function needs a call object or named lambda environment to be created
+  // in order to execute the function. This is done in the Stack or JIT frame
+  // setup code _before_ the bytecode prologue starts.
+  NeedsFunctionEnvironmentObjects = 1 << 23,
+
+  // An extra VarScope is used as the body scope instead of the normal
+  // FunctionScope. This is needed when parameter expressions are used AND the
+  // function has var bindings or a sloppy-direct-eval. For example,
+  //    `function(x = eval("")) { var y; }`
+  FunctionHasExtraBodyVarScope = 1 << 24,
+
+  // This function must define the implicit `arguments` binding on the function
+  // scope. If there are no free uses or an appropriate explicit binding exists,
+  // then this flag is unset.
+  //
+  // Note: Parameter expressions will not see an explicit `var arguments;`
+  // binding in the body and an implicit binding on the function-scope must
+  // still be used in that case.
+  ShouldDeclareArguments = 1 << 25,
+
+  // This function has a local (implicit or explicit) `arguments` binding. This
+  // binding is initialized by the JSOp::Arguments bytecode.
+  //
+  // Technically, every function has a binding named `arguments`. Internally,
+  // this binding is only added when `arguments` is mentioned by the function
+  // body.
+  //
+  // Examples:
+  //   ```
+  //    // Explicit definition
+  //    function f() { var arguments; return arguments; }
+  //
+  //    // Implicit use
+  //    function f() { return arguments; }
+  //
+  //    // Implicit use in arrow function
+  //    function f() { return () => arguments; }
+  //
+  //    // Implicit use in parameter expression
+  //    function f(a = arguments) { return a; }
+  //   ```
+  NeedsArgsObj = 1 << 26,
+
+  // This function must use the "mapped" form of an arguments object. This flag
+  // is set independently of whether we actually use an `arguments` binding. The
+  // conditions are specified in the ECMAScript spec.
+  HasMappedArgsObj = 1 << 27,
+
+  // Large self-hosted methods that should be inlined anyway by the JIT for
+  // performance reasons can be marked with this flag.
+  IsInlinableLargeFunction = 1 << 28,
+
+  // This function has an internal .newTarget binding and we need to emit
+  // JSOp::NewTarget in the prologue to initialize it. This binding may be
+  // used directly for "new.target", or indirectly (e.g. in super() calls).
+  FunctionHasNewTargetBinding = 1 << 29,
+
+  // Whether this is a self-hosted function that uses the ArgumentsLength or
+  // GetArgument intrinsic.
+  UsesArgumentsIntrinsics = 1 << 30,
+};
+
+enum class MutableScriptFlagsEnum : uint32_t {
+  // Number of times the |warmUpCount| was forcibly discarded. The counter is
+  // reset when a script is successfully jit-compiled.
+  WarmupResets_MASK = 0xFF,
+
+  // If treatAsRunOnce, whether script has executed.
+  HasRunOnce = 1 << 8,
+
+  // Script has been reused for a clone.
+  HasBeenCloned = 1 << 9,
+
+  // Script has an entry in Realm::scriptCountsMap.
+  HasScriptCounts = 1 << 10,
+
+  // Script has an entry in Realm::debugScriptMap.
+  HasDebugScript = 1 << 11,
+
+  // (1 << 12) is unused.
+  // (1 << 13) is unused.
+
+  // Script supports relazification where it releases bytecode and gcthings to
+  // save memory. This process is opt-in since various complexities may disallow
+  // this for some scripts.
+  // NOTE: Must check for isRelazifiable() before setting this flag.
+  AllowRelazify = 1 << 14,
+
+  // Set if the script has opted into spew.
+  SpewEnabled = 1 << 15,
+
+  // Set if we care about a script's final warmup count.
+  NeedsFinalWarmUpCount = 1 << 16,
+
+  //
+  // IonMonkey compilation hints.
+  //
+
+  // Whether Baseline or Ion compilation has been disabled for this script.
+  // IonDisabled is equivalent to |jitScript->canIonCompile() == false| but
+  // JitScript can be discarded on GC and we don't want this to affect
+  // observable behavior (see ArgumentsGetterImpl comment).
+  BaselineDisabled = 1 << 17,
+  IonDisabled = 1 << 18,
+
+  // This script should not be inlined into others. This happens after inlining
+  // has failed.
+  Uninlineable = 1 << 19,
+
+  // Indicates that this script has no eager baseline hint available
+  // in the cache, used to prevent further lookups.
+  NoEagerBaselineHint = 1 << 20,
+
+  // *****************************************************************
+  // The flags below are set when we bail out and invalidate a script.
+  // When we recompile, we will be more conservative.
+  // *****************************************************************
+
+  // A hoisted bounds check bailed out.
+  FailedBoundsCheck = 1 << 21,
+
+  // An instruction hoisted by LICM bailed out.
+  HadLICMInvalidation = 1 << 22,
+
+  // An instruction hoisted by InstructionReordering bailed out.
+  HadReorderingBailout = 1 << 23,
+
+  // An instruction inserted or truncated by Range Analysis bailed out.
+  HadEagerTruncationBailout = 1 << 24,
+
+  // A lexical check bailed out.
+  FailedLexicalCheck = 1 << 25,
+
+  // A guard inserted by phi specialization bailed out.
+  HadSpeculativePhiBailout = 1 << 26,
+
+  // An unbox folded with a load bailed out.
+  HadUnboxFoldingBailout = 1 << 27,
+};
+
+// Retrievable source can be retrieved using the source hook (and therefore
+// need not be XDR'd, can be discarded if desired because it can always be
+// reconstituted later, etc.).
+enum class SourceRetrievable { No = 0, Yes };
+
+}  // namespace js
+
+#endif /* vm_StencilEnums_h */