#37662

Committed 25 Oct 2023 07:08AM UTC coverage: 87.999% (+1.5%) from 86.476%

Build # #37662

Build Type

push

local

Committed by

web-flow

Commit Message

Improve efficiency of minimum/maximum(::Diagonal) (#30236)

```
julia> DM = Diagonal(rand(100));

julia> @btime minimum($DM);    # before
  27.987 μs (0 allocations: 0 bytes)

julia> @btime minimum($DM);    # after
  246.091 ns (0 allocations: 0 bytes)
```

Run Details

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68.97

/base/refpointer.jl

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

"""
    Ref{T}

An object that safely references data of type `T`. This type is guaranteed to point to
valid, Julia-allocated memory of the correct type. The underlying data is protected from
freeing by the garbage collector as long as the `Ref` itself is referenced.

In Julia, `Ref` objects are dereferenced (loaded or stored) with `[]`.

Creation of a `Ref` to a value `x` of type `T` is usually written `Ref(x)`.
Additionally, for creating interior pointers to containers (such as Array or Ptr),
it can be written `Ref(a, i)` for creating a reference to the `i`-th element of `a`.

`Ref{T}()` creates a reference to a value of type `T` without initialization.
For a bitstype `T`, the value will be whatever currently resides in the memory
allocated. For a non-bitstype `T`, the reference will be undefined and attempting to
dereference it will result in an error, "UndefRefError: access to undefined reference".

To check if a `Ref` is an undefined reference, use [`isassigned(ref::RefValue)`](@ref).
For example, `isassigned(Ref{T}())` is `false` if `T` is not a bitstype.
If `T` is a bitstype, `isassigned(Ref{T}())` will always be true.

When passed as a `ccall` argument (either as a `Ptr` or `Ref` type), a `Ref`
object will be converted to a native pointer to the data it references.
For most `T`, or when converted to a `Ptr{Cvoid}`, this is a pointer to the
object data. When `T` is an `isbits` type, this value may be safely mutated,
otherwise mutation is strictly undefined behavior.

As a special case, setting `T = Any` will instead cause the creation of a
pointer to the reference itself when converted to a `Ptr{Any}`
(a `jl_value_t const* const*` if T is immutable, else a `jl_value_t *const *`).
When converted to a `Ptr{Cvoid}`, it will still return a pointer to the data
region as for any other `T`.

A `C_NULL` instance of `Ptr` can be passed to a `ccall` `Ref` argument to initialize it.

# Use in broadcasting
`Ref` is sometimes used in broadcasting in order to treat the referenced values as a scalar.

# Examples

```jldoctest
julia> r = Ref(5) # Create a Ref with an initial value
Base.RefValue{Int64}(5)

julia> r[] # Getting a value from a Ref
5

julia> r[] = 7 # Storing a new value in a Ref
7

julia> r # The Ref now contains 7
Base.RefValue{Int64}(7)

julia> isa.(Ref([1,2,3]), [Array, Dict, Int]) # Treat reference values as scalar during broadcasting
3-element BitVector:
 1
 0
 0

julia> Ref{Function}()  # Undefined reference to a non-bitstype, Function
Base.RefValue{Function}(#undef)

julia> try
           Ref{Function}()[] # Dereferencing an undefined reference will result in an error
       catch e
           println(e)
       end
UndefRefError()

julia> Ref{Int64}()[]; # A reference to a bitstype refers to an undetermined value if not given

julia> isassigned(Ref{Int64}()) # A reference to a bitstype is always assigned
true
```
"""
Ref

# C NUL-terminated string pointers; these can be used in ccall
# instead of Ptr{Cchar} and Ptr{Cwchar_t}, respectively, to enforce
# a check for embedded NUL chars in the string (to avoid silent truncation).
if Int === Int64
    primitive type Cstring  64 end
    primitive type Cwstring 64 end
else
    primitive type Cstring  32 end
    primitive type Cwstring 32 end
end


### General Methods for Ref{T} type

eltype(x::Type{<:Ref{T}}) where {T} = @isdefined(T) ? T : Any
convert(::Type{Ref{T}}, x::Ref{T}) where {T} = x
size(x::Ref) = ()
axes(x::Ref) = ()
length(x::Ref) = 1
isempty(x::Ref) = false
ndims(x::Ref) = 0
ndims(::Type{<:Ref}) = 0
iterate(r::Ref) = (r[], nothing)
iterate(r::Ref, s) = nothing
IteratorSize(::Type{<:Ref}) = HasShape{0}()

# create Ref objects for general object conversion
unsafe_convert(::Type{Ref{T}}, x::Ref{T}) where {T} = unsafe_convert(Ptr{T}, x)
unsafe_convert(::Type{Ref{T}}, x) where {T} = unsafe_convert(Ptr{T}, x)

convert(::Type{Ref{T}}, x) where {T} = RefValue{T}(x)::RefValue{T}

### Methods for a Ref object that is backed by an array at index i
struct RefArray{T,A<:AbstractArray{T},R} <: Ref{T}
    x::A
    i::Int
    roots::R # should be either ::Nothing or ::Any
    RefArray{T,A,R}(x,i,roots=nothing) where {T,A<:AbstractArray{T},R} = new(x,i,roots)
end
RefArray(x::AbstractArray{T}, i::Int, roots::Any) where {T} = RefArray{T,typeof(x),Any}(x, i, roots)
RefArray(x::AbstractArray{T}, i::Int=1, roots::Nothing=nothing) where {T} = RefArray{T,typeof(x),Nothing}(x, i, nothing)
RefArray(x::AbstractArray{T}, i::Integer, roots::Any) where {T} = RefArray{T,typeof(x),Any}(x, Int(i), roots)
RefArray(x::AbstractArray{T}, i::Integer, roots::Nothing=nothing) where {T} = RefArray{T,typeof(x),Nothing}(x, Int(i), nothing)
convert(::Type{Ref{T}}, x::AbstractArray{T}) where {T} = RefArray(x, 1)

function unsafe_convert(P::Union{Type{Ptr{T}},Type{Ptr{Cvoid}}}, b::RefArray{T})::P where T
    if allocatedinline(T)
        p = pointer(b.x, b.i)
    elseif isconcretetype(T) && ismutabletype(T)
        p = pointer_from_objref(b.x[b.i])
    else
        # see comment on equivalent branch for RefValue
        p = pointerref(Ptr{Ptr{Cvoid}}(pointer(b.x, b.i)), 1, Core.sizeof(Ptr{Cvoid}))
    end
    return p
end
function unsafe_convert(::Type{Ptr{Any}}, b::RefArray{Any})::Ptr{Any}
    return pointer(b.x, b.i)
end

###
if is_primary_base_module
    Ref(x::Any) = RefValue(x)
    Ref{T}() where {T} = RefValue{T}() # Ref{T}()
    Ref{T}(x) where {T} = RefValue{T}(x) # Ref{T}(x)

    Ref(x::Ref, i::Integer) = (i != 1 && error("Ref only has one element"); x)
    Ref(x::Ptr{T}, i::Integer) where {T} = x + (i - 1) * Core.sizeof(T)

    # convert Arrays to pointer arrays for ccall
    # For example `["a", "b"]` to Ptr{Cstring} for `char **argv`
    function Ref{P}(a::Array{T}) where P<:Union{Ptr,Cwstring,Cstring} where T
        if (isbitstype(T) ? T <: Ptr || T <: Union{Cwstring,Cstring} : T <: eltype(P))
            # this Array already has the right memory layout for the requested Ref
            # but the wrong eltype for the constructor
            return RefArray{P,typeof(a),Nothing}(a, 1, nothing) # effectively a no-op
        else
            ptrs = Vector{P}(undef, length(a)+1)
            roots = Vector{Any}(undef, length(a))
            for i = 1:length(a)
                root = cconvert(P, a[i])
                ptrs[i] = unsafe_convert(P, root)::P
                roots[i] = root
            end
            ptrs[length(a)+1] = C_NULL
            return RefArray{P,typeof(ptrs),typeof(roots)}(ptrs, 1, roots)
        end
    end
    Ref(x::AbstractArray, i::Integer) = RefArray(x, i)
end

cconvert(::Type{Ptr{P}}, a::Array{P}) where {P<:Union{Ptr,Cwstring,Cstring}} = a
cconvert(::Type{Ref{P}}, a::Array{P}) where {P<:Union{Ptr,Cwstring,Cstring}} = a
cconvert(::Type{Ptr{P}}, a::Array) where {P<:Union{Ptr,Cwstring,Cstring}} = Ref{P}(a)
cconvert(::Type{Ref{P}}, a::Array) where {P<:Union{Ptr,Cwstring,Cstring}} = Ref{P}(a)

# pass NTuple{N,T} as Ptr{T}/Ref{T}
cconvert(::Type{Ref{T}}, t::NTuple{N,T}) where {N,T} = Ref{NTuple{N,T}}(t)
cconvert(::Type{Ref{T}}, r::Ref{NTuple{N,T}}) where {N,T} = r
unsafe_convert(::Type{Ref{T}}, r::Ref{NTuple{N,T}}) where {N,T} =
    convert(Ptr{T}, unsafe_convert(Ptr{NTuple{N,T}}, r))
unsafe_convert(::Type{Ptr{T}}, r::Ref{NTuple{N,T}}) where {N,T} =
    convert(Ptr{T}, unsafe_convert(Ptr{NTuple{N,T}}, r))
unsafe_convert(::Type{Ptr{T}}, r::Ptr{NTuple{N,T}}) where {N,T} =
    convert(Ptr{T}, r)

###

getindex(b::RefArray) = b.x[b.i]
setindex!(b::RefArray, x) = (b.x[b.i] = x; b)

###

"""
    LLVMPtr{T, AS}

A pointer type that more closely resembles LLVM semantics: It includes the pointer address
space, and will be passed as an actual pointer instead of an integer.

This type is mainly used to interface with code that has strict requirements about pointers,
e.g., intrinsics that are selected based on the address space, or back-ends that require
pointers to be identifiable by their types.
"""
Core.LLVMPtr

1	# This file is a part of Julia. License is MIT: https://julialang.org/license
2
3	"""
4	Ref{T}
5
6	An object that safely references data of type `T`. This type is guaranteed to point to
7	valid, Julia-allocated memory of the correct type. The underlying data is protected from
8	freeing by the garbage collector as long as the `Ref` itself is referenced.
9
10	In Julia, `Ref` objects are dereferenced (loaded or stored) with `[]`.
11
12	Creation of a `Ref` to a value `x` of type `T` is usually written `Ref(x)`.
13	Additionally, for creating interior pointers to containers (such as Array or Ptr),
14	it can be written `Ref(a, i)` for creating a reference to the `i`-th element of `a`.
15
16	`Ref{T}()` creates a reference to a value of type `T` without initialization.
17	For a bitstype `T`, the value will be whatever currently resides in the memory
18	allocated. For a non-bitstype `T`, the reference will be undefined and attempting to
19	dereference it will result in an error, "UndefRefError: access to undefined reference".
20
21	To check if a `Ref` is an undefined reference, use [`isassigned(ref::RefValue)`](@ref).
22	For example, `isassigned(Ref{T}())` is `false` if `T` is not a bitstype.
23	If `T` is a bitstype, `isassigned(Ref{T}())` will always be true.
24
25	When passed as a `ccall` argument (either as a `Ptr` or `Ref` type), a `Ref`
26	object will be converted to a native pointer to the data it references.
27	For most `T`, or when converted to a `Ptr{Cvoid}`, this is a pointer to the
28	object data. When `T` is an `isbits` type, this value may be safely mutated,
29	otherwise mutation is strictly undefined behavior.
30
31	As a special case, setting `T = Any` will instead cause the creation of a
32	pointer to the reference itself when converted to a `Ptr{Any}`
33	(a `jl_value_t const* const` if T is immutable, else a `jl_value_t const *`).
34	When converted to a `Ptr{Cvoid}`, it will still return a pointer to the data
35	region as for any other `T`.
36
37	A `C_NULL` instance of `Ptr` can be passed to a `ccall` `Ref` argument to initialize it.
38
39	# Use in broadcasting
40	`Ref` is sometimes used in broadcasting in order to treat the referenced values as a scalar.
41
42	# Examples
43
44	```jldoctest
45	julia> r = Ref(5) # Create a Ref with an initial value
46	Base.RefValue{Int64}(5)
47
48	julia> r[] # Getting a value from a Ref
49	5
50
51	julia> r[] = 7 # Storing a new value in a Ref
52	7
53
54	julia> r # The Ref now contains 7
55	Base.RefValue{Int64}(7)
56
57	julia> isa.(Ref([1,2,3]), [Array, Dict, Int]) # Treat reference values as scalar during broadcasting
58	3-element BitVector:
59	1
60	0
61	0
62
63	julia> Ref{Function}() # Undefined reference to a non-bitstype, Function
64	Base.RefValue{Function}(#undef)
65
66	julia> try
67	Ref{Function}()[] # Dereferencing an undefined reference will result in an error
68	catch e
69	println(e)
70	end
71	UndefRefError()
72
73	julia> Ref{Int64}()[]; # A reference to a bitstype refers to an undetermined value if not given
74
75	julia> isassigned(Ref{Int64}()) # A reference to a bitstype is always assigned
76	true
77	```
78	"""
79	Ref
80
81	# C NUL-terminated string pointers; these can be used in ccall
82	# instead of Ptr{Cchar} and Ptr{Cwchar_t}, respectively, to enforce
83	# a check for embedded NUL chars in the string (to avoid silent truncation).
84	if Int === Int64
85	primitive type Cstring 64 end
86	primitive type Cwstring 64 end
87	else
88	primitive type Cstring 32 end
89	primitive type Cwstring 32 end
90	end
91
92
93	### General Methods for Ref{T} type
94
95	eltype(x::Type{<:Ref{T}}) where {T} = @isdefined(T) ? T : Any	1,577,107✔
96	convert(::Type{Ref{T}}, x::Ref{T}) where {T} = x	×
97	size(x::Ref) = ()	1✔
98	axes(x::Ref) = ()	1,577,133✔
99	length(x::Ref) = 1	×
100	isempty(x::Ref) = false	×
101	ndims(x::Ref) = 0	1✔
102	ndims(::Type{<:Ref}) = 0	1,577,203✔
103	iterate(r::Ref) = (r[], nothing)	2✔
104	iterate(r::Ref, s) = nothing	2✔
105	IteratorSize(::Type{<:Ref}) = HasShape{0}()	2✔
106
107	# create Ref objects for general object conversion
108	unsafe_convert(::Type{Ref{T}}, x::Ref{T}) where {T} = unsafe_convert(Ptr{T}, x)	84,880,696✔
109	unsafe_convert(::Type{Ref{T}}, x) where {T} = unsafe_convert(Ptr{T}, x)	×
110
111	convert(::Type{Ref{T}}, x) where {T} = RefValue{T}(x)::RefValue{T}	26,910,898✔
112
113	### Methods for a Ref object that is backed by an array at index i
114	struct RefArray{T,A<:AbstractArray{T},R} <: Ref{T}
115	x::A
116	i::Int
117	roots::R # should be either ::Nothing or ::Any
118	RefArray{T,A,R}(x,i,roots=nothing) where {T,A<:AbstractArray{T},R} = new(x,i,roots)	39,876✔
119	end
120	RefArray(x::AbstractArray{T}, i::Int, roots::Any) where {T} = RefArray{T,typeof(x),Any}(x, i, roots)	×
121	RefArray(x::AbstractArray{T}, i::Int=1, roots::Nothing=nothing) where {T} = RefArray{T,typeof(x),Nothing}(x, i, nothing)	67,272✔
122	RefArray(x::AbstractArray{T}, i::Integer, roots::Any) where {T} = RefArray{T,typeof(x),Any}(x, Int(i), roots)	×
123	RefArray(x::AbstractArray{T}, i::Integer, roots::Nothing=nothing) where {T} = RefArray{T,typeof(x),Nothing}(x, Int(i), nothing)	8,076✔
124	convert(::Type{Ref{T}}, x::AbstractArray{T}) where {T} = RefArray(x, 1)	9✔
125
126	function unsafe_convert(P::Union{Type{Ptr{T}},Type{Ptr{Cvoid}}}, b::RefArray{T})::P where T	79✔
127	if allocatedinline(T)	79✔
128	p = pointer(b.x, b.i)	2,238✔
129	elseif isconcretetype(T) && ismutabletype(T)	×
130	p = pointer_from_objref(b.x[b.i])	×
131	else
132	# see comment on equivalent branch for RefValue
133	p = pointerref(Ptr{Ptr{Cvoid}}(pointer(b.x, b.i)), 1, Core.sizeof(Ptr{Cvoid}))	×
134	end
135	return p	79✔
136	end
137	function unsafe_convert(::Type{Ptr{Any}}, b::RefArray{Any})::Ptr{Any}	×
138	return pointer(b.x, b.i)	×
139	end
140
141	###
142	if is_primary_base_module
143	Ref(x::Any) = RefValue(x)	11,284,953✔
144	Ref{T}() where {T} = RefValue{T}() # Ref{T}()	39,128,209✔
145	Ref{T}(x) where {T} = RefValue{T}(x) # Ref{T}(x)	43,101,978✔
146
147	Ref(x::Ref, i::Integer) = (i != 1 && error("Ref only has one element"); x)	×
148	Ref(x::Ptr{T}, i::Integer) where {T} = x + (i - 1) * Core.sizeof(T)	×
149
150	# convert Arrays to pointer arrays for ccall
151	# For example `["a", "b"]` to Ptr{Cstring} for `char **argv`
152	function Ref{P}(a::Array{T}) where P<:Union{Ptr,Cwstring,Cstring} where T	2,202✔
153	if (isbitstype(T) ? T <: Ptr \|\| T <: Union{Cwstring,Cstring} : T <: eltype(P))	×
154	# this Array already has the right memory layout for the requested Ref
155	# but the wrong eltype for the constructor
156	return RefArray{P,typeof(a),Nothing}(a, 1, nothing) # effectively a no-op	×
157	else
158	ptrs = Vector{P}(undef, length(a)+1)	2,202✔
159	roots = Vector{Any}(undef, length(a))	2,202✔
160	for i = 1:length(a)	4,403✔
161	root = cconvert(P, a[i])	45,002✔
162	ptrs[i] = unsafe_convert(P, root)::P	45,002✔
163	roots[i] = root	45,002✔
164	end	87,803✔
165	ptrs[length(a)+1] = C_NULL	2,202✔
166	return RefArray{P,typeof(ptrs),typeof(roots)}(ptrs, 1, roots)	2,202✔
167	end
168	end
169	Ref(x::AbstractArray, i::Integer) = RefArray(x, i)	37,665✔
170	end
171
172	cconvert(::Type{Ptr{P}}, a::Array{P}) where {P<:Union{Ptr,Cwstring,Cstring}} = a	×
173	cconvert(::Type{Ref{P}}, a::Array{P}) where {P<:Union{Ptr,Cwstring,Cstring}} = a	×
174	cconvert(::Type{Ptr{P}}, a::Array) where {P<:Union{Ptr,Cwstring,Cstring}} = Ref{P}(a)	2,159✔
175	cconvert(::Type{Ref{P}}, a::Array) where {P<:Union{Ptr,Cwstring,Cstring}} = Ref{P}(a)	43✔
176
177	# pass NTuple{N,T} as Ptr{T}/Ref{T}
178	cconvert(::Type{Ref{T}}, t::NTuple{N,T}) where {N,T} = Ref{NTuple{N,T}}(t)	4✔
179	cconvert(::Type{Ref{T}}, r::Ref{NTuple{N,T}}) where {N,T} = r	3✔
180	unsafe_convert(::Type{Ref{T}}, r::Ref{NTuple{N,T}}) where {N,T} =	7✔
181	convert(Ptr{T}, unsafe_convert(Ptr{NTuple{N,T}}, r))
182	unsafe_convert(::Type{Ptr{T}}, r::Ref{NTuple{N,T}}) where {N,T} =	51,973✔
183	convert(Ptr{T}, unsafe_convert(Ptr{NTuple{N,T}}, r))
184	unsafe_convert(::Type{Ptr{T}}, r::Ptr{NTuple{N,T}}) where {N,T} =	×
185	convert(Ptr{T}, r)
186
187	###
188
189	getindex(b::RefArray) = b.x[b.i]	37,641✔
190	setindex!(b::RefArray, x) = (b.x[b.i] = x; b)	2✔
191
192	###
193
194	"""
195	LLVMPtr{T, AS}
196
197	A pointer type that more closely resembles LLVM semantics: It includes the pointer address
198	space, and will be passed as an actual pointer instead of an integer.
199
200	This type is mainly used to interface with code that has strict requirements about pointers,
201	e.g., intrinsics that are selected based on the address space, or back-ends that require
202	pointers to be identifiable by their types.
203	"""
204	Core.LLVMPtr

JuliaLang / julia / #37662

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