# This file is a part of Julia. License is MIT: https://julialang.org/license

# commented-out definitions are implemented in C

#abstract type Any <: Any end
#abstract type Type{T} end

#abstract type Vararg{T} end

#mutable struct Symbol
## opaque
#end

#mutable struct TypeName
#    name::Symbol
#end

#mutable struct DataType <: Type
#    name::TypeName
#    super::Type
#    parameters::Tuple
#    names::Tuple
#    types::Tuple
#    ctor
#    instance
#    size::Int32
#    abstract::Bool
#    mutable::Bool
#    pointerfree::Bool
#end

#struct Union <: Type
#    a
#    b
#end

#mutable struct TypeVar
#    name::Symbol
#    lb::Type
#    ub::Type
#end

#struct UnionAll
#    var::TypeVar
#    body
#end

#struct Nothing
#end
#const nothing = Nothing()

#abstract type AbstractArray{T,N} end
#abstract type DenseArray{T,N} <: AbstractArray{T,N} end

#primitive type AddrSpace{Backend::Module} 8 end
#const CPU = bitcast(AddrSpace{Core}, 0x00)

#struct GenericMemory{kind::Symbol, T, AS::AddrSpace}
#   length::Int
#   const data::Ptr{Cvoid} # make this GenericPtr{addrspace, Cvoid}
#   Union{ # hidden data
#       elements :: NTuple{length, T}
#       owner :: Any
#   }
#end

#struct GenericMemoryRef{kind::Symbol, T, AS::AddrSpace}
#    mem::GenericMemory{kind, T, AS}
#    data::Ptr{Cvoid} # make this GenericPtr{addrspace, Cvoid}
#end

#mutable struct Array{T,N} <: DenseArray{T,N}
#  ref::MemoryRef{T}
#  size::NTuple{N,Int}
#end

#mutable struct Module
## opaque
#end

#mutable struct SimpleVector
## opaque
#end

#mutable struct String
## opaque
#end

#mutable struct Method
#...
#end

#mutable struct MethodInstance
#...
#end

#mutable struct CodeInstance
#...
#end

#mutable struct CodeInfo
#...
#end

#mutable struct TypeMapLevel
#...
#end

#mutable struct TypeMapEntry
#...
#end

#abstract type Ref{T} end
#primitive type Ptr{T} <: Ref{T} {32|64} end

# types for the front end

#mutable struct Expr
#    head::Symbol
#    args::Array{Any,1}
#end

#struct LineNumberNode
#    line::Int
#    file::Union{Symbol,Nothing}
#end

#struct LegacyLineInfoNode end # only used internally during lowering

#struct DebugInfo
#    def::Any # (Union{Symbol, Method, MethodInstance})
#    linetable::Any # (Union{Nothing,DebugInfo})
#    edges::SimpleVector # Vector{DebugInfo}
#    codelocs::String # compressed Vector{UInt8}
#end

#struct GotoNode
#    label::Int
#end

#struct GotoIfNot
#    cond::Any
#    dest::Int
#end

#struct ReturnNode
#    val::Any
#end

#struct PiNode
#    val
#    typ
#end

#struct PhiNode
#    edges::Vector{Int32}
#    values::Vector{Any}
#end

#struct PhiCNode
#    values::Vector{Any}
#end

#struct UpsilonNode
#    val
#end

#struct QuoteNode
#    value
#end

#struct GlobalRef
#    mod::Module
#    name::Symbol
#end

#mutable struct Task
#    next::Any
#    queue::Any
#    storage::Any
#    donenotify::Any
#    result::Any
#    scope::Any
#    code::Any
#    @atomic _state::UInt8
#    sticky::UInt8
#    priority::UInt16
#    @atomic _isexception::UInt8
#    pad00::UInt8
#    pad01::UInt8
#    pad02::UInt8
#    rngState0::UInt64
#    rngState1::UInt64
#    rngState2::UInt64
#    rngState3::UInt64
#    rngState4::UInt64
#    const metrics_enabled::Bool
#    pad10::UInt8
#    pad11::UInt8
#    pad12::UInt8
#    @atomic first_enqueued_at::UInt64
#    @atomic last_started_running_at::UInt64
#    @atomic running_time_ns::UInt64
#    @atomic finished_at::UInt64
#end

export
    # key types
    Any, DataType, Vararg, NTuple,
    Tuple, Type, UnionAll, TypeVar, Union, Nothing, Cvoid,
    AbstractArray, DenseArray, NamedTuple, Pair,
    # special objects
    Function, Method, Module, Symbol, Task, UndefInitializer, undef, WeakRef, VecElement,
    Array, Memory, MemoryRef, AtomicMemory, AtomicMemoryRef, GenericMemory, GenericMemoryRef,
    # numeric types
    Number, Real, Integer, Bool, Ref, Ptr,
    AbstractFloat, Float16, Float32, Float64,
    Signed, Int, Int8, Int16, Int32, Int64, Int128,
    Unsigned, UInt, UInt8, UInt16, UInt32, UInt64, UInt128,
    # string types
    AbstractChar, Char, AbstractString, String, IO,
    # errors
    ErrorException, BoundsError, DivideError, DomainError, Exception,
    InterruptException, InexactError, OutOfMemoryError, ReadOnlyMemoryError,
    OverflowError, StackOverflowError, SegmentationFault, UndefRefError, UndefVarError,
    TypeError, ArgumentError, MethodError, AssertionError, LoadError, InitError,
    UndefKeywordError, ConcurrencyViolationError, FieldError,
    # AST representation
    Expr, QuoteNode, LineNumberNode, GlobalRef,
    # object model functions
    fieldtype, getfield, setfield!, swapfield!, modifyfield!, replacefield!, setfieldonce!,
    nfields, throw, tuple, ===, isdefined,
    # access to globals
    getglobal, setglobal!, swapglobal!, modifyglobal!, replaceglobal!, setglobalonce!, isdefinedglobal,
    # ifelse, sizeof    # not exported, to avoid conflicting with Base
    # type reflection
    <:, typeof, isa, typeassert,
    # method reflection
    applicable, invoke,
    # constants
    nothing, Main,
    # backwards compatibility
    arrayref, arrayset, arraysize, const_arrayref

const getproperty = getfield # TODO: use `getglobal` for modules instead
const setproperty! = setfield!

abstract type Number end
abstract type Real     <: Number end
abstract type AbstractFloat <: Real end
abstract type Integer  <: Real end
abstract type Signed   <: Integer end
abstract type Unsigned <: Integer end

primitive type Float16 <: AbstractFloat 16 end
primitive type Float32 <: AbstractFloat 32 end
primitive type Float64 <: AbstractFloat 64 end

primitive type BFloat16 <: AbstractFloat 16 end

#primitive type Bool <: Integer 8 end
abstract type AbstractChar end
primitive type Char <: AbstractChar 32 end

primitive type Int8    <: Signed   8 end
#primitive type UInt8   <: Unsigned 8 end
primitive type Int16   <: Signed   16 end
#primitive type UInt16  <: Unsigned 16 end
#primitive type Int32   <: Signed   32 end
#primitive type UInt32  <: Unsigned 32 end
#primitive type Int64   <: Signed   64 end
#primitive type UInt64  <: Unsigned 64 end
primitive type Int128  <: Signed   128 end
primitive type UInt128 <: Unsigned 128 end

if Int === Int64
    const UInt = UInt64
else
    const UInt = UInt32
end

function Typeof end
ccall(:jl_toplevel_eval_in, Any, (Any, Any),
      Core, quote
      (f::typeof(Typeof))(x) = ($(_expr(:meta,:nospecialize,:x)); isa(x,Type) ? Type{x} : typeof(x))
      end)

function iterate end

macro nospecialize(x)
    _expr(:meta, :nospecialize, x)
end
Expr(@nospecialize args...) = _expr(args...)

macro latestworld() Expr(:latestworld) end

_is_internal(__module__) = __module__ === Core
# can be used in place of `@assume_effects :total` (supposed to be used for bootstrapping)
macro _total_meta()
    return _is_internal(__module__) && Expr(:meta, Expr(:purity,
        #=:consistent=#true,
        #=:effect_free=#true,
        #=:nothrow=#true,
        #=:terminates_globally=#true,
        #=:terminates_locally=#false,
        #=:notaskstate=#true,
        #=:inaccessiblememonly=#true,
        #=:noub=#true,
        #=:noub_if_noinbounds=#false,
        #=:consistent_overlay=#false,
        #=:nortcall=#true))
end
# can be used in place of `@assume_effects :foldable` (supposed to be used for bootstrapping)
macro _foldable_meta()
    return _is_internal(__module__) && Expr(:meta, Expr(:purity,
        #=:consistent=#true,
        #=:effect_free=#true,
        #=:nothrow=#false,
        #=:terminates_globally=#true,
        #=:terminates_locally=#false,
        #=:notaskstate=#true,
        #=:inaccessiblememonly=#true,
        #=:noub=#true,
        #=:noub_if_noinbounds=#false,
        #=:consistent_overlay=#false,
        #=:nortcall=#true))
end

macro inline()   Expr(:meta, :inline)   end
macro noinline() Expr(:meta, :noinline) end

macro _boundscheck() Expr(:boundscheck) end

# n.b. the effects and model of these is refined in inference abstractinterpretation.jl
TypeVar(@nospecialize(n)) = _typevar(n::Symbol, Union{}, Any)
TypeVar(@nospecialize(n), @nospecialize(ub)) = _typevar(n::Symbol, Union{}, ub)
TypeVar(@nospecialize(n), @nospecialize(lb), @nospecialize(ub)) = _typevar(n::Symbol, lb, ub)
UnionAll(@nospecialize(v), @nospecialize(t)) = ccall(:jl_type_unionall, Any, (Any, Any), v::TypeVar, t)

const Memory{T} = GenericMemory{:not_atomic, T, CPU}
const MemoryRef{T} = GenericMemoryRef{:not_atomic, T, CPU}

# simple convert for use by constructors of types in Core
# note that there is no actual conversion defined here,
# so the methods and ccall's in Core aren't permitted to use convert
convert(::Type{Any}, @nospecialize(x)) = x
convert(::Type{T}, x::T) where {T} = x
cconvert(::Type{T}, x) where {T} = convert(T, x)
unsafe_convert(::Type{T}, x::T) where {T} = x

# will be inserted by the frontend for closures
_typeof_captured_variable(@nospecialize t) = (@_total_meta; t isa Type && has_free_typevars(t) ? typeof(t) : Typeof(t))

has_free_typevars(@nospecialize t) = (@_total_meta; ccall(:jl_has_free_typevars, Int32, (Any,), t) === Int32(1))

# dispatch token indicating a kwarg (keyword sorter) call
function kwcall end
# deprecated internal functions:
kwfunc(@nospecialize(f)) = kwcall
kwftype(@nospecialize(t)) = typeof(kwcall)

# Let the compiler assume that calling Union{} as a constructor does not need
# to be considered ever (which comes up often as Type{<:T} inference, and
# occasionally in user code from eltype).
Union{}(a...) = throw(ArgumentError("cannot construct a value of type Union{} for return result"))
kwcall(kwargs, ::Type{Union{}}, a...) = Union{}(a...)

abstract type Exception end
struct ErrorException <: Exception
    msg::AbstractString
end

struct BoundsError <: Exception
    a::Any
    i::Any
    BoundsError() = new()
    BoundsError(@nospecialize(a)) = (@noinline; new(a))
    BoundsError(@nospecialize(a), i) = (@noinline; new(a,i))
end
struct DivideError         <: Exception end
struct OutOfMemoryError    <: Exception end
struct ReadOnlyMemoryError <: Exception end
struct SegmentationFault   <: Exception end
struct StackOverflowError  <: Exception end
struct UndefRefError       <: Exception end
struct UndefVarError <: Exception
    var::Symbol
    world::UInt
    scope # a Module or Symbol or other object describing the context where this variable was looked for (e.g. Main or :local or :static_parameter)
    UndefVarError(var::Symbol) = new(var, ccall(:jl_get_tls_world_age, UInt, ()))
    UndefVarError(var::Symbol, @nospecialize scope) = new(var, ccall(:jl_get_tls_world_age, UInt, ()), scope)
end
struct ConcurrencyViolationError <: Exception
    msg::AbstractString
end
struct MissingCodeError <: Exception
    mi::MethodInstance
end
struct InterruptException <: Exception end
struct DomainError <: Exception
    val
    msg::AbstractString
    DomainError(@nospecialize(val)) = (@noinline; new(val, ""))
    DomainError(@nospecialize(val), @nospecialize(msg)) = (@noinline; new(val, msg))
end
struct TypeError <: Exception
    # `func` is the name of the builtin function that encountered a type error,
    # the name of the type that hit an error in its definition or application, or
    # some other brief description of where the error happened.
    # `context` optionally adds extra detail, e.g. the name of the type parameter
    # that got a bad value.
    func::Symbol
    context::Union{AbstractString,GlobalRef,Symbol}
    expected::Type
    got
    TypeError(func, context, @nospecialize(expected::Type), @nospecialize(got)) =
        new(func, context, expected, got)
end
TypeError(where, @nospecialize(expected::Type), @nospecialize(got)) =
    TypeError(Symbol(where), "", expected, got)
struct InexactError <: Exception
    func::Symbol
    args
    InexactError(f::Symbol, @nospecialize(args...)) = (@noinline; new(f, args))
end
struct OverflowError <: Exception
    msg::AbstractString
end

struct ArgumentError <: Exception
    msg::AbstractString
end
struct UndefKeywordError <: Exception
    var::Symbol
end

const typemax_UInt = Intrinsics.sext_int(UInt, 0xFF)
const typemax_Int = Core.Intrinsics.udiv_int(Core.Intrinsics.sext_int(Int, 0xFF), 2)

struct MethodError <: Exception
    f
    args
    world::UInt
    MethodError(@nospecialize(f), @nospecialize(args), world::UInt) = new(f, args, world)
end
MethodError(@nospecialize(f), @nospecialize(args)) = MethodError(f, args, typemax_UInt)

struct AssertionError <: Exception
    msg::AbstractString
end
AssertionError() = AssertionError("")

struct FieldError <: Exception
    type::DataType
    field::Symbol
end

abstract type WrappedException <: Exception end

struct LoadError <: WrappedException
    file::AbstractString
    line::Int
    error
end

struct InitError <: WrappedException
    mod::Symbol
    error
end

struct ABIOverride
    abi::Type
    def::MethodInstance
    ABIOverride(@nospecialize(abi::Type), def::MethodInstance) = new(abi, def)
end

struct PrecompilableError <: Exception end
struct TrimFailure <: Exception end

String(s::String) = s  # no constructor yet

const Cvoid = Nothing
Nothing() = nothing

# This should always be inlined
getptls() = ccall(:jl_get_ptls_states, Ptr{Cvoid}, ())

include(m::Module, fname::String) = (@noinline; ccall(:jl_load_, Any, (Any, Any), m, fname))
eval(m::Module, @nospecialize(e)) = (@noinline; ccall(:jl_toplevel_eval_in, Any, (Any, Any), m, e))

struct EvalInto <: Function
    m::Module
end
(this::EvalInto)(@nospecialize(e)) = eval(this.m, e)

mutable struct Box
    contents::Any
    Box(@nospecialize(x)) = new(x)
    Box() = new()
end

# constructors for built-in types

mutable struct WeakRef
    value
    WeakRef() = WeakRef(nothing)
    WeakRef(@nospecialize(v)) = ccall(:jl_gc_new_weakref_th, Ref{WeakRef},
                                      (Ptr{Cvoid}, Any), getptls(), v)
end

Tuple{}() = ()

struct VecElement{T}
    value::T
    VecElement{T}(value::T) where {T} = new(value) # disable converting constructor in Core
end
VecElement(arg::T) where {T} = VecElement{T}(arg)

eval(Core, quote
    GotoNode(label::Int) = $(Expr(:new, :GotoNode, :label))
    NewvarNode(slot::SlotNumber) = $(Expr(:new, :NewvarNode, :slot))
    QuoteNode(@nospecialize value) = $(Expr(:new, :QuoteNode, :value))
    SSAValue(id::Int) = $(Expr(:new, :SSAValue, :id))
    Argument(n::Int) = $(Expr(:new, :Argument, :n))
    ReturnNode(@nospecialize val) = $(Expr(:new, :ReturnNode, :val))
    ReturnNode() = $(Expr(:new, :ReturnNode)) # unassigned val indicates unreachable
    GotoIfNot(@nospecialize(cond), dest::Int) = $(Expr(:new, :GotoIfNot, :cond, :dest))
    EnterNode(dest::Int) = $(Expr(:new, :EnterNode, :dest))
    EnterNode(dest::Int, @nospecialize(scope)) = $(Expr(:new, :EnterNode, :dest, :scope))
    LineNumberNode(l::Int) = $(Expr(:new, :LineNumberNode, :l, nothing))
    function LineNumberNode(l::Int, @nospecialize(f))
        isa(f, String) && (f = Symbol(f))
        return $(Expr(:new, :LineNumberNode, :l, :f))
    end
    DebugInfo(def::Union{Method,MethodInstance,Symbol}, linetable::Union{Nothing,DebugInfo}, edges::SimpleVector, codelocs::String) =
        $(Expr(:new, :DebugInfo, :def, :linetable, :edges, :codelocs))
    DebugInfo(def::Union{Method,MethodInstance,Symbol}) =
        $(Expr(:new, :DebugInfo, :def, nothing, Core.svec(), ""))
    SlotNumber(n::Int) = $(Expr(:new, :SlotNumber, :n))
    PhiNode(edges::Array{Int32, 1}, values::Array{Any, 1}) = $(Expr(:new, :PhiNode, :edges, :values))
    PiNode(@nospecialize(val), @nospecialize(typ)) = $(Expr(:new, :PiNode, :val, :typ))
    PhiCNode(values::Array{Any, 1}) = $(Expr(:new, :PhiCNode, :values))
    UpsilonNode(@nospecialize(val)) = $(Expr(:new, :UpsilonNode, :val))
    UpsilonNode() = $(Expr(:new, :UpsilonNode))
    Const(@nospecialize(v)) = $(Expr(:new, :Const, :v))
    _PartialStruct(@nospecialize(typ), undef, fields::Array{Any, 1}) = $(Expr(:new, :PartialStruct, :typ, :undef, :fields))
    PartialOpaque(@nospecialize(typ), @nospecialize(env), parent::MethodInstance, source) = $(Expr(:new, :PartialOpaque, :typ, :env, :parent, :source))
    InterConditional(slot::Int, @nospecialize(thentype), @nospecialize(elsetype)) = $(Expr(:new, :InterConditional, :slot, :thentype, :elsetype))
    MethodMatch(@nospecialize(spec_types), sparams::SimpleVector, method::Method, fully_covers::Bool) = $(Expr(:new, :MethodMatch, :spec_types, :sparams, :method, :fully_covers))
end)

const NullDebugInfo = DebugInfo(:none)

struct LineInfoNode # legacy support for aiding Serializer.deserialize of old IR
    mod::Module
    method
    file::Symbol
    line::Int32
    inlined_at::Int32
    LineInfoNode(mod::Module, @nospecialize(method), file::Symbol, line::Int32, inlined_at::Int32) = new(mod, method, file, line, inlined_at)
end


function CodeInstance(
    mi::Union{MethodInstance, ABIOverride}, owner, @nospecialize(rettype), @nospecialize(exctype), @nospecialize(inferred_const),
    @nospecialize(inferred), const_flags::Int32, min_world::UInt, max_world::UInt,
    effects::UInt32, @nospecialize(analysis_results),
    di::Union{DebugInfo,Nothing}, edges::SimpleVector)
    return ccall(:jl_new_codeinst, Ref{CodeInstance},
        (Any, Any, Any, Any, Any, Any, Int32, UInt, UInt, UInt32, Any, Any, Any),
        mi, owner, rettype, exctype, inferred_const, inferred, const_flags, min_world, max_world,
        effects, analysis_results, di, edges)
end
GlobalRef(m::Module, s::Symbol) = ccall(:jl_module_globalref, Ref{GlobalRef}, (Any, Any), m, s)
Module(name::Symbol=:anonymous, std_imports::Bool=true, default_names::Bool=true) = ccall(:jl_f_new_module, Ref{Module}, (Any, Bool, Bool), name, std_imports, default_names)

function _Task(@nospecialize(f), reserved_stack::Int, completion_future)
    return ccall(:jl_new_task, Ref{Task}, (Any, Any, Int), f, completion_future, reserved_stack)
end

const NTuple{N,T} = Tuple{Vararg{T,N}}

## primitive Array constructors
struct UndefInitializer end
const undef = UndefInitializer()

# type and dimensionality specified
(self::Type{GenericMemory{kind,T,addrspace}})(::UndefInitializer, m::Int) where {T,addrspace,kind} = memorynew(self, m)
(self::Type{GenericMemory{kind,T,addrspace}})(::UndefInitializer, d::NTuple{1,Int}) where {T,kind,addrspace} = self(undef, getfield(d,1))
# empty vector constructor
(self::Type{GenericMemory{kind,T,addrspace}})() where {T,kind,addrspace} = self(undef, 0)

# memoryref is simply convenience wrapper function around memoryrefnew
memoryref(mem::GenericMemory) = memoryrefnew(mem)
memoryref(mem::GenericMemory, i::Integer) = memoryrefnew(mem, Int(i), @_boundscheck)
memoryref(ref::GenericMemoryRef, i::Integer) = memoryrefnew(ref, Int(i), @_boundscheck)
GenericMemoryRef(mem::GenericMemory) = memoryref(mem)
GenericMemoryRef(mem::GenericMemory, i::Integer) = memoryref(mem, i)
GenericMemoryRef(mem::GenericMemoryRef, i::Integer) = memoryref(mem, i)

const AtomicMemory{T} = GenericMemory{:atomic, T, CPU}
const AtomicMemoryRef{T} = GenericMemoryRef{:atomic, T, CPU}

# construction helpers for Array
new_as_memoryref(self::Type{GenericMemoryRef{kind,T,addrspace}}, m::Int) where {T,kind,addrspace} = memoryref(fieldtype(self, :mem)(undef, m))

# checked-multiply intrinsic function for dimensions
_checked_mul_dims() = 1, false
_checked_mul_dims(m::Int) = m, Intrinsics.ule_int(typemax_Int, m) # equivalently: (m + 1) < 1
function _checked_mul_dims(m::Int, n::Int)
    b = Intrinsics.checked_smul_int(m, n)
    a = getfield(b, 1)
    ovflw = getfield(b, 2)
    ovflw = Intrinsics.or_int(ovflw, Intrinsics.ule_int(typemax_Int, m))
    ovflw = Intrinsics.or_int(ovflw, Intrinsics.ule_int(typemax_Int, n))
    return a, ovflw
end
function _checked_mul_dims(m::Int, d::Int...)
    @_foldable_meta # the compiler needs to know this loop terminates
    a = m
    i = 1
    ovflw = false
    neg = Intrinsics.ule_int(typemax_Int, m)
    zero = false # if m==0 we won't have overflow since we go left to right
    while Intrinsics.sle_int(i, nfields(d))
        di = getfield(d, i)
        b = Intrinsics.checked_smul_int(a, di)
        zero = Intrinsics.or_int(zero, di === 0)
        ovflw = Intrinsics.or_int(ovflw, getfield(b, 2))
        neg = Intrinsics.or_int(neg, Intrinsics.ule_int(typemax_Int, di))
        a = getfield(b, 1)
        i = Intrinsics.add_int(i, 1)
   end
   return a, Intrinsics.or_int(neg, Intrinsics.and_int(ovflw, Intrinsics.not_int(zero)))
end

# convert a set of dims to a length, with overflow checking
checked_dims() = 1
checked_dims(m::Int) = m # defer this check to Memory constructor instead
function checked_dims(d::Int...)
    b = _checked_mul_dims(d...)
    getfield(b, 2) && throw(ArgumentError("invalid Array dimensions"))
    return getfield(b, 1)
end

# type and dimensionality specified, accepting dims as series of Ints
eval(Core, :(function (self::Type{Array{T,1}})(::UndefInitializer, m::Int) where {T}
    mem = fieldtype(fieldtype(self, :ref), :mem)(undef, m)
    return $(Expr(:new, :self, :(memoryref(mem)), :((m,))))
end))
eval(Core, :(function (self::Type{Array{T,2}})(::UndefInitializer, m::Int, n::Int) where {T}
    return $(Expr(:new, :self, :(new_as_memoryref(fieldtype(self, :ref), checked_dims(m, n))), :((m, n))))
end))
eval(Core, :(function (self::Type{Array{T,3}})(::UndefInitializer, m::Int, n::Int, o::Int) where {T}
    return $(Expr(:new, :self, :(new_as_memoryref(fieldtype(self, :ref), checked_dims(m, n, o))), :((m, n, o))))
end))
eval(Core, :(function (self::Type{Array{T, N}})(::UndefInitializer, d::Vararg{Int, N}) where {T, N}
    return $(Expr(:new, :self, :(new_as_memoryref(fieldtype(self, :ref), checked_dims(d...))), :d))
end))
# type and dimensionality specified, accepting dims as tuples of Ints
(self::Type{Array{T,1}})(::UndefInitializer, d::NTuple{1, Int}) where {T} = self(undef, getfield(d, 1))
(self::Type{Array{T,2}})(::UndefInitializer, d::NTuple{2, Int}) where {T} = self(undef, getfield(d, 1), getfield(d, 2))
(self::Type{Array{T,3}})(::UndefInitializer, d::NTuple{3, Int}) where {T} = self(undef, getfield(d, 1), getfield(d, 2), getfield(d, 3))
(self::Type{Array{T,N}})(::UndefInitializer, d::NTuple{N, Int}) where {T, N} = self(undef, d...)
# type but not dimensionality specified
Array{T}(::UndefInitializer, m::Int) where {T} = Array{T, 1}(undef, m)
Array{T}(::UndefInitializer, m::Int, n::Int) where {T} = Array{T, 2}(undef, m, n)
Array{T}(::UndefInitializer, m::Int, n::Int, o::Int) where {T} = Array{T, 3}(undef, m, n, o)
Array{T}(::UndefInitializer, d::NTuple{N, Int}) where {T, N} = Array{T, N}(undef, d)
# empty vector constructor
(self::Type{Array{T, 1}})() where {T} = self(undef, 0)

(Array{T, N} where T)(x::AbstractArray{S, N}) where {S, N} = Array{S, N}(x)

Array(A::AbstractArray{T, N})    where {T, N}   = Array{T, N}(A)
Array{T}(A::AbstractArray{S, N}) where {T, N, S} = Array{T, N}(A)

AbstractArray{T}(A::AbstractArray{S, N}) where {T, S, N} = AbstractArray{T, N}(A)

# primitive Symbol constructors

## Helper for proper GC rooting without unsafe_convert
eval(Core, quote
    _Symbol(ptr::Ptr{UInt8}, sz::Int, root::Any) = $(Expr(:foreigncall, QuoteNode(:jl_symbol_n),
        Ref{Symbol}, svec(Ptr{UInt8}, Int), 0, QuoteNode(:ccall), :ptr, :sz, :root))
end)

function Symbol(s::String)
    @_foldable_meta
    @noinline
    return _Symbol(ccall(:jl_string_ptr, Ptr{UInt8}, (Any,), s), sizeof(s), s)
end
function Symbol(a::Array{UInt8, 1})
    @noinline
    return _Symbol(bitcast(Ptr{UInt8}, a.ref.ptr_or_offset), getfield(a.size, 1), a.ref.mem)
end
Symbol(s::Symbol) = s

# Minimal implementations of using/import for bootstrapping (supports only
# `import .M: a, b, c, ...`, little error checking)
let
    fail() = throw(ArgumentError("unsupported import/using while bootstrapping"))
    length(a::Array{T, 1}) where {T} = getfield(getfield(a, :size), 1)
    function getindex(A::Array, i::Int)
        Intrinsics.ult_int(Intrinsics.bitcast(UInt, Intrinsics.sub_int(i, 1)), Intrinsics.bitcast(UInt, length(A))) || fail()
        memoryrefget(memoryrefnew(getfield(A, :ref), i, false), :not_atomic, false)
    end
    x == y = Intrinsics.eq_int(x, y)
    x + y = Intrinsics.add_int(x, y)
    x <= y = Intrinsics.sle_int(x, y)

    global function _eval_import(explicit::Bool, to::Module, from::Union{Expr, Nothing}, paths::Expr...)
        from isa Expr || fail()
        if length(from.args) == 2 && getindex(from.args, 1) === :.
            from = getglobal(to, getindex(from.args, 2))
        elseif length(from.args) == 1 && getindex(from.args, 1) === :Core
            from = Core
        elseif length(from.args) == 1 && getindex(from.args, 1) === :Base
            from = Main.Base
        else
            fail()
        end
        from isa Module || fail()
        i = 1
        while i <= nfields(paths)
            a = getfield(paths, i).args
            length(a) == 1 || fail()
            s = getindex(a, 1)
            Core._import(to, from, s, s, explicit)
            i += 1
        end
    end

    global function _eval_using(to::Module, path::Expr)
        getindex(path.args, 1) === :. || fail()
        from = getglobal(to, getindex(path.args, 2))
        i = 3
        while i <= length(path.args)
            from = getfield(from, getindex(path.args, i))
            i += 1
        end
        from isa Module || fail()
        Core._using(to, from)
    end
end

# module providing the IR object model
# excluding types already exported by Core (GlobalRef, QuoteNode, Expr, LineNumberNode)
# any type beyond these is self-quoting (see also Base.isa_ast_node)
module IR

export CodeInfo, MethodInstance, CodeInstance, GotoNode, GotoIfNot, ReturnNode,
    NewvarNode, SSAValue, SlotNumber, Argument,
    PiNode, PhiNode, PhiCNode, UpsilonNode, DebugInfo,
    Const, PartialStruct, InterConditional, EnterNode

using Core: CodeInfo, MethodInstance, CodeInstance, GotoNode, GotoIfNot, ReturnNode,
    NewvarNode, SSAValue, SlotNumber, Argument,
    PiNode, PhiNode, PhiCNode, UpsilonNode, DebugInfo,
    Const, PartialStruct, InterConditional, EnterNode

end # module IR

# docsystem basics
macro doc(x...)
    docex = atdoc(__source__, __module__, x...)
    isa(docex, Expr) && docex.head === :escape && return docex
    return Expr(:escape, Expr(:var"hygienic-scope", docex, typeof(atdoc).name.module, __source__))
end
macro __doc__(x)
    return Expr(:escape, Expr(:block, Expr(:meta, :doc), x))
end

isbasicdoc(@nospecialize x) = (isa(x, Expr) && x.head === :.) || isa(x, Union{QuoteNode, Symbol})
firstarg(arg1, args...) = arg1
iscallexpr(ex::Expr) = (isa(ex, Expr) && ex.head === :where) ? iscallexpr(firstarg(ex.args...)) : (isa(ex, Expr) && ex.head === :call)
iscallexpr(ex) = false
function ignoredoc(source, mod, str, expr)
    (isbasicdoc(expr) || iscallexpr(expr)) && return Expr(:escape, nothing)
    Expr(:escape, expr)
end

global atdoc = ignoredoc
atdoc!(λ)    = global atdoc = λ

# macros for big integer syntax
macro int128_str end
macro uint128_str end
macro big_str end

# macro for command syntax
macro cmd end


# simple stand-alone print definitions for debugging
abstract type IO end
struct CoreSTDOUT <: IO end
struct CoreSTDERR <: IO end
const stdout = CoreSTDOUT()
const stderr = CoreSTDERR()
io_pointer(::CoreSTDOUT) = Intrinsics.pointerref(Intrinsics.cglobal(:jl_uv_stdout, Ptr{Cvoid}), 1, 1)
io_pointer(::CoreSTDERR) = Intrinsics.pointerref(Intrinsics.cglobal(:jl_uv_stderr, Ptr{Cvoid}), 1, 1)

unsafe_write(io::IO, x::Ptr{UInt8}, nb::UInt) =
    (ccall(:jl_uv_puts, Cvoid, (Ptr{Cvoid}, Ptr{UInt8}, UInt), io_pointer(io), x, nb); nb)
unsafe_write(io::IO, x::Ptr{UInt8}, nb::Int) =
    (ccall(:jl_uv_puts, Cvoid, (Ptr{Cvoid}, Ptr{UInt8}, Int), io_pointer(io), x, nb); nb)
write(io::IO, x::UInt8) =
    (ccall(:jl_uv_putb, Cvoid, (Ptr{Cvoid}, UInt8), io_pointer(io), x); 1)
function write(io::IO, x::String)
    nb = sizeof(x)
    unsafe_write(io, ccall(:jl_string_ptr, Ptr{UInt8}, (Any,), x), nb)
    return nb
end

show(io::IO, @nospecialize x) = ccall(:jl_static_show, Cvoid, (Ptr{Cvoid}, Any), io_pointer(io), x)
print(io::IO, x::AbstractChar) = ccall(:jl_uv_putc, Cvoid, (Ptr{Cvoid}, Char), io_pointer(io), x)
print(io::IO, x::String) = (write(io, x); nothing)
print(io::IO, @nospecialize x) = show(io, x)
print(io::IO, @nospecialize(x), @nospecialize a...) = (print(io, x); print(io, a...))
println(io::IO) = (write(io, 0x0a); nothing) # 0x0a = '\n'
println(io::IO, @nospecialize x...) = (print(io, x...); println(io))

show(@nospecialize a) = show(stdout, a)
print(@nospecialize a...) = print(stdout, a...)
println(@nospecialize a...) = println(stdout, a...)

struct GeneratedFunctionStub
    gen
    argnames::SimpleVector
    spnames::SimpleVector
end

# If the generator is a subtype of this trait, inference caches the generated unoptimized
# code, sacrificing memory space to improve the performance of subsequent inferences.
# This tradeoff is not appropriate in general cases (e.g., for `GeneratedFunctionStub`s
# generated from the front end), but it can be justified for generators involving complex
# code transformations, such as a Cassette-like system.
abstract type CachedGenerator end

NamedTuple() = NamedTuple{(),Tuple{}}(())

eval(Core, :(NamedTuple{names}(args::Tuple) where {names} =
             $(Expr(:splatnew, :(NamedTuple{names,typeof(args)}), :args))))

using .Intrinsics: sle_int, add_int

eval(Core, :((NT::Type{NamedTuple{names,T}})(args::T) where {names, T <: Tuple} =
             $(Expr(:splatnew, :NT, :args))))

# constructors for built-in types

import .Intrinsics: eq_int, trunc_int, lshr_int, sub_int, shl_int, bitcast, sext_int, zext_int, and_int

function is_top_bit_set(x)
    @inline
    eq_int(trunc_int(UInt8, lshr_int(x, sub_int(shl_int(sizeof(x), 3), 1))), trunc_int(UInt8, 1))
end

function is_top_bit_set(x::Union{Int8,UInt8})
    @inline
    eq_int(lshr_int(x, 7), trunc_int(typeof(x), 1))
end

# n.b. This function exists for CUDA to overload to configure error behavior (see #48097)
throw_inexacterror(func::Symbol, to, val) = throw(InexactError(func, to, val))

function check_sign_bit(::Type{To}, x) where {To}
    @inline
    # the top bit is the sign bit of x but "sign bit" sounds better in stacktraces
    # n.b. if x is signed, then sizeof(x) === sizeof(To), otherwise sizeof(x) >= sizeof(To)
    is_top_bit_set(x) && throw_inexacterror(sizeof(x) === sizeof(To) ? :convert : :trunc, To, x)
    x
end

function checked_trunc_sint(::Type{To}, x::From) where {To,From}
    @inline
    y = trunc_int(To, x)
    back = sext_int(From, y)
    eq_int(x, back) || throw_inexacterror(:trunc, To, x)
    y
end

function checked_trunc_uint(::Type{To}, x::From) where {To,From}
    @inline
    y = trunc_int(To, x)
    back = zext_int(From, y)
    eq_int(x, back) || throw_inexacterror(:trunc, To, x)
    y
end

toInt8(x::Int8)       = x
toInt8(x::Int16)      = checked_trunc_sint(Int8, x)
toInt8(x::Int32)      = checked_trunc_sint(Int8, x)
toInt8(x::Int64)      = checked_trunc_sint(Int8, x)
toInt8(x::Int128)     = checked_trunc_sint(Int8, x)
toInt8(x::UInt8)      = bitcast(Int8, check_sign_bit(Int8, x))
toInt8(x::UInt16)     = checked_trunc_sint(Int8, check_sign_bit(Int8, x))
toInt8(x::UInt32)     = checked_trunc_sint(Int8, check_sign_bit(Int8, x))
toInt8(x::UInt64)     = checked_trunc_sint(Int8, check_sign_bit(Int8, x))
toInt8(x::UInt128)    = checked_trunc_sint(Int8, check_sign_bit(Int8, x))
toInt8(x::Bool)       = and_int(bitcast(Int8, x), Int8(1))
toInt16(x::Int8)      = sext_int(Int16, x)
toInt16(x::Int16)     = x
toInt16(x::Int32)     = checked_trunc_sint(Int16, x)
toInt16(x::Int64)     = checked_trunc_sint(Int16, x)
toInt16(x::Int128)    = checked_trunc_sint(Int16, x)
toInt16(x::UInt8)     = zext_int(Int16, x)
toInt16(x::UInt16)    = bitcast(Int16, check_sign_bit(Int16, x))
toInt16(x::UInt32)    = checked_trunc_sint(Int16, check_sign_bit(Int16, x))
toInt16(x::UInt64)    = checked_trunc_sint(Int16, check_sign_bit(Int16, x))
toInt16(x::UInt128)   = checked_trunc_sint(Int16, check_sign_bit(Int16, x))
toInt16(x::Bool)      = and_int(zext_int(Int16, x), Int16(1))
toInt32(x::Int8)      = sext_int(Int32, x)
toInt32(x::Int16)     = sext_int(Int32, x)
toInt32(x::Int32)     = x
toInt32(x::Int64)     = checked_trunc_sint(Int32, x)
toInt32(x::Int128)    = checked_trunc_sint(Int32, x)
toInt32(x::UInt8)     = zext_int(Int32, x)
toInt32(x::UInt16)    = zext_int(Int32, x)
toInt32(x::UInt32)    = bitcast(Int32, check_sign_bit(Int32, x))
toInt32(x::UInt64)    = checked_trunc_sint(Int32, check_sign_bit(Int32, x))
toInt32(x::UInt128)   = checked_trunc_sint(Int32, check_sign_bit(Int32, x))
toInt32(x::Bool)      = and_int(zext_int(Int32, x), Int32(1))
toInt64(x::Int8)      = sext_int(Int64, x)
toInt64(x::Int16)     = sext_int(Int64, x)
toInt64(x::Int32)     = sext_int(Int64, x)
toInt64(x::Int64)     = x
toInt64(x::Int128)    = checked_trunc_sint(Int64, x)
toInt64(x::UInt8)     = zext_int(Int64, x)
toInt64(x::UInt16)    = zext_int(Int64, x)
toInt64(x::UInt32)    = zext_int(Int64, x)
toInt64(x::UInt64)    = bitcast(Int64, check_sign_bit(Int64, x))
toInt64(x::UInt128)   = checked_trunc_sint(Int64, check_sign_bit(Int64, x))
toInt64(x::Bool)      = and_int(zext_int(Int64, x), Int64(1))
toInt128(x::Int8)     = sext_int(Int128, x)
toInt128(x::Int16)    = sext_int(Int128, x)
toInt128(x::Int32)    = sext_int(Int128, x)
toInt128(x::Int64)    = sext_int(Int128, x)
toInt128(x::Int128)   = x
toInt128(x::UInt8)    = zext_int(Int128, x)
toInt128(x::UInt16)   = zext_int(Int128, x)
toInt128(x::UInt32)   = zext_int(Int128, x)
toInt128(x::UInt64)   = zext_int(Int128, x)
toInt128(x::UInt128)  = bitcast(Int128, check_sign_bit(Int128, x))
toInt128(x::Bool)     = and_int(zext_int(Int128, x), Int128(1))
toUInt8(x::Int8)      = bitcast(UInt8, check_sign_bit(UInt8, x))
toUInt8(x::Int16)     = checked_trunc_uint(UInt8, x)
toUInt8(x::Int32)     = checked_trunc_uint(UInt8, x)
toUInt8(x::Int64)     = checked_trunc_uint(UInt8, x)
toUInt8(x::Int128)    = checked_trunc_uint(UInt8, x)
toUInt8(x::UInt8)     = x
toUInt8(x::UInt16)    = checked_trunc_uint(UInt8, x)
toUInt8(x::UInt32)    = checked_trunc_uint(UInt8, x)
toUInt8(x::UInt64)    = checked_trunc_uint(UInt8, x)
toUInt8(x::UInt128)   = checked_trunc_uint(UInt8, x)
toUInt8(x::Bool)      = and_int(bitcast(UInt8, x), UInt8(1))
toUInt16(x::Int8)     = sext_int(UInt16, check_sign_bit(UInt16, x))
toUInt16(x::Int16)    = bitcast(UInt16, check_sign_bit(UInt16, x))
toUInt16(x::Int32)    = checked_trunc_uint(UInt16, x)
toUInt16(x::Int64)    = checked_trunc_uint(UInt16, x)
toUInt16(x::Int128)   = checked_trunc_uint(UInt16, x)
toUInt16(x::UInt8)    = zext_int(UInt16, x)
toUInt16(x::UInt16)   = x
toUInt16(x::UInt32)   = checked_trunc_uint(UInt16, x)
toUInt16(x::UInt64)   = checked_trunc_uint(UInt16, x)
toUInt16(x::UInt128)  = checked_trunc_uint(UInt16, x)
toUInt16(x::Bool)     = and_int(zext_int(UInt16, x), UInt16(1))
toUInt32(x::Int8)     = sext_int(UInt32, check_sign_bit(UInt32, x))
toUInt32(x::Int16)    = sext_int(UInt32, check_sign_bit(UInt32, x))
toUInt32(x::Int32)    = bitcast(UInt32, check_sign_bit(UInt32, x))
toUInt32(x::Int64)    = checked_trunc_uint(UInt32, x)
toUInt32(x::Int128)   = checked_trunc_uint(UInt32, x)
toUInt32(x::UInt8)    = zext_int(UInt32, x)
toUInt32(x::UInt16)   = zext_int(UInt32, x)
toUInt32(x::UInt32)   = x
toUInt32(x::UInt64)   = checked_trunc_uint(UInt32, x)
toUInt32(x::UInt128)  = checked_trunc_uint(UInt32, x)
toUInt32(x::Bool)     = and_int(zext_int(UInt32, x), UInt32(1))
toUInt64(x::Int8)     = sext_int(UInt64, check_sign_bit(UInt64, x))
toUInt64(x::Int16)    = sext_int(UInt64, check_sign_bit(UInt64, x))
toUInt64(x::Int32)    = sext_int(UInt64, check_sign_bit(UInt64, x))
toUInt64(x::Int64)    = bitcast(UInt64, check_sign_bit(UInt64, x))
toUInt64(x::Int128)   = checked_trunc_uint(UInt64, x)
toUInt64(x::UInt8)    = zext_int(UInt64, x)
toUInt64(x::UInt16)   = zext_int(UInt64, x)
toUInt64(x::UInt32)   = zext_int(UInt64, x)
toUInt64(x::UInt64)   = x
toUInt64(x::UInt128)  = checked_trunc_uint(UInt64, x)
toUInt64(x::Bool)     = and_int(zext_int(UInt64, x), UInt64(1))
toUInt128(x::Int8)    = sext_int(UInt128, check_sign_bit(UInt128, x))
toUInt128(x::Int16)   = sext_int(UInt128, check_sign_bit(UInt128, x))
toUInt128(x::Int32)   = sext_int(UInt128, check_sign_bit(UInt128, x))
toUInt128(x::Int64)   = sext_int(UInt128, check_sign_bit(UInt128, x))
toUInt128(x::Int128)  = bitcast(UInt128, check_sign_bit(UInt128, x))
toUInt128(x::UInt8)   = zext_int(UInt128, x)
toUInt128(x::UInt16)  = zext_int(UInt128, x)
toUInt128(x::UInt32)  = zext_int(UInt128, x)
toUInt128(x::UInt64)  = zext_int(UInt128, x)
toUInt128(x::UInt128) = x
toUInt128(x::Bool)    = and_int(zext_int(UInt128, x), UInt128(1))

# TODO: this is here to work around the 4 method limit in inference (#23210).
const BuiltinInts = Union{Int128, Int16, Int32, Int64, Int8, UInt128, UInt16, UInt32, UInt64, UInt8, Bool}
Int8(x::BuiltinInts)    = toInt8(x)::Int8
Int16(x::BuiltinInts)   = toInt16(x)::Int16
Int32(x::BuiltinInts)   = toInt32(x)::Int32
Int64(x::BuiltinInts)   = toInt64(x)::Int64
Int128(x::BuiltinInts)  = toInt128(x)::Int128
UInt8(x::BuiltinInts)   = toUInt8(x)::UInt8
UInt16(x::BuiltinInts)  = toUInt16(x)::UInt16
UInt32(x::BuiltinInts)  = toUInt32(x)::UInt32
UInt64(x::BuiltinInts)  = toUInt64(x)::UInt64
UInt128(x::BuiltinInts) = toUInt128(x)::UInt128

(::Type{T})(x::T) where {T<:Number} = x

Int(x::Ptr)  = bitcast(Int, x)
UInt(x::Ptr) = bitcast(UInt, x)
if Int === Int32
Int64(x::Ptr) = Int64(UInt32(x))
UInt64(x::Ptr) = UInt64(UInt32(x))
end
(PT::Type{Ptr{T}} where T)(x::Union{Int,UInt,Ptr}=0) = bitcast(PT, x)
(AS::Type{AddrSpace{Backend}} where Backend)(x::UInt8) = bitcast(AS, x)

Signed(x::UInt8)    = Int8(x)
Unsigned(x::Int8)   = UInt8(x)
Signed(x::UInt16)   = Int16(x)
Unsigned(x::Int16)  = UInt16(x)
Signed(x::UInt32)   = Int32(x)
Unsigned(x::Int32)  = UInt32(x)
Signed(x::UInt64)   = Int64(x)
Unsigned(x::Int64)  = UInt64(x)
Signed(x::UInt128)  = Int128(x)
Unsigned(x::Int128) = UInt128(x)

Signed(x::Union{Float16, Float32, Float64, Bool})   = Int(x)
Unsigned(x::Union{Float16, Float32, Float64, Bool}) = UInt(x)

Integer(x::Integer) = x
Integer(x::Union{Float16, Float32, Float64}) = Int(x)

# During definition of struct type `B`, if an `A.B` expression refers to
# the eventual global name of the struct, then return the partially-initialized
# type object.
# TODO: remove. This is a shim for backwards compatibility.
function struct_name_shim(@nospecialize(x), name::Symbol, mod::Module, @nospecialize(t))
    return x === mod ? t : getfield(x, name)
end

# Bindings for the julia frontend.  The internal jl_parse and jl_lower will call
# Core._parse and Core._lower respectively (if they are not `nothing`.)

#    Core._parse(text, filename, lineno, offset, options)
#
# Parse Julia code from the buffer `text`, starting at `offset` and attributing
# it to `filename`. `text` may be a `String` or `svec(ptr::Ptr{UInt8},
# len::Int)` for a raw unmanaged buffer. `options` should be one of `:atom`,
# `:statement` or `:all`, indicating how much the parser will consume.
#
# `_parse` must return an `svec` containing an `Expr` and the new offset as an
# `Int`.
_parse = nothing

#    Core._lower(code, module, filename="none", linenum=0, world=0xfff..., warn=false)
#
# Lower `code` (usually Expr), returning `svec(e::Any xs::Any...)` where `e` is
# the lowered code, and `xs` is possible additional information from
# JuliaLowering (TBD).
_lower = nothing

_setparser!(parser) = setglobal!(Core, :_parse, parser)
_setlowerer!(lowerer) = setglobal!(Core, :_lower, lowerer)

# support for deprecated uses of builtin functions
_apply(x...) = _apply_iterate(Main.Base.iterate, x...)
const _apply_pure = _apply
const _call_latest = invokelatest
const _call_in_world = invoke_in_world

struct Pair{A, B}
    first::A
    second::B
    # if we didn't inline this, it's probably because the callsite was actually dynamic
    # to avoid potentially compiling many copies of this, we mark the arguments with `@nospecialize`
    # but also mark the whole function with `@inline` to ensure we will inline it whenever possible
    # (even if `convert(::Type{A}, a::A)` for some reason was expensive)
    Pair(a, b) = new{typeof(a), typeof(b)}(a, b)
    function Pair{A, B}(@nospecialize(a), @nospecialize(b)) where {A, B}
        @inline
        return new(a::A, b::B)
    end
end

function _hasmethod(@nospecialize(tt)) # this function has a special tfunc
    world = ccall(:jl_get_tls_world_age, UInt, ()) # tls_world_age()
    return Intrinsics.not_int(ccall(:jl_gf_invoke_lookup, Any, (Any, Any, UInt), tt, nothing, world) === nothing)
end

# for backward compat
arrayref(inbounds::Bool, A::Array, i::Int...) = Main.Base.getindex(A, i...)
const_arrayref(inbounds::Bool, A::Array, i::Int...) = Main.Base.getindex(A, i...)
arrayset(inbounds::Bool, A::Array{T}, x::Any, i::Int...) where {T} = Main.Base.setindex!(A, x::T, i...)
arraysize(a::Array) = a.size
arraysize(a::Array, i::Int) = sle_int(i, nfields(a.size)) ? getfield(a.size, i) : 1
const check_top_bit = check_sign_bit

# For convenience
EnterNode(old::EnterNode, new_dest::Int) = isdefined(old, :scope) ?
    EnterNode(new_dest, old.scope) : EnterNode(new_dest)

# typename(_).constprop_heuristic
const FORCE_CONST_PROP      = 0x1
const ARRAY_INDEX_HEURISTIC = 0x2
const ITERATE_HEURISTIC     = 0x3
const SAMETYPE_HEURISTIC    = 0x4

# `typename` has special tfunc support in inference to improve
# the result for `Type{Union{...}}`. It is defined here, so that the Compiler
# can look it up by value.
struct TypeNameError <: Exception
    a
    TypeNameError(@nospecialize(a)) = new(a)
end

typename(a) = throw(TypeNameError(a))
typename(a::DataType) = a.name
function typename(a::Union)
    ta = typename(a.a)
    tb = typename(a.b)
    ta === tb || throw(TypeNameError(a))
    return tb
end
typename(union::UnionAll) = typename(union.body)

# Special inference support to avoid execess specialization of these methods.
# TODO: Replace this by a generic heuristic.
(>:)(@nospecialize(a), @nospecialize(b)) = (b <: a)
(!==)(@nospecialize(a), @nospecialize(b)) = Intrinsics.not_int(a === b)

include(Core, "optimized_generics.jl")

ccall(:jl_set_istopmod, Cvoid, (Any, Bool), Core, true)
