# This file is a part of Julia. License is MIT: https://julialang.org/license isexpr(@nospecialize(ex), heads) = isa(ex, Expr) && in(ex.head, heads) isexpr(@nospecialize(ex), heads, n::Int) = isa(ex, Expr) && in(ex.head, heads) && length(ex.args) == n const is_expr = isexpr ## symbols ## """ gensym([tag]) Generates a symbol which will not conflict with other variable names (in the same module). """ gensym() = ccall(:jl_gensym, Ref{Symbol}, ()) gensym(s::String) = ccall(:jl_tagged_gensym, Ref{Symbol}, (Ptr{UInt8}, Csize_t), s, sizeof(s)) gensym(ss::String...) = map(gensym, ss) gensym(s::Symbol) = ccall(:jl_tagged_gensym, Ref{Symbol}, (Ptr{UInt8}, Csize_t), s, -1 % Csize_t) """ @gensym Generates a gensym symbol for a variable. For example, `@gensym x y` is transformed into `x = gensym("x"); y = gensym("y")`. """ macro gensym(names...) blk = Expr(:block) for name in names push!(blk.args, :($(esc(name)) = gensym($(string(name))))) end push!(blk.args, :nothing) return blk end ## expressions ## isexpr(@nospecialize(ex), head::Symbol) = isa(ex, Expr) && ex.head === head isexpr(@nospecialize(ex), head::Symbol, n::Int) = isa(ex, Expr) && ex.head === head && length(ex.args) == n copy(e::Expr) = exprarray(e.head, copy_exprargs(e.args)) # copy parts of an AST that the compiler mutates function copy_exprs(@nospecialize(x)) if isa(x, Expr) return copy(x) elseif isa(x, PhiNode) values = x.values nvalues = length(values) new_values = Vector{Any}(undef, nvalues) @inbounds for i = 1:nvalues isassigned(values, i) || continue new_values[i] = copy_exprs(values[i]) end return PhiNode(copy(x.edges), new_values) elseif isa(x, PhiCNode) values = x.values nvalues = length(values) new_values = Vector{Any}(undef, nvalues) @inbounds for i = 1:nvalues isassigned(values, i) || continue new_values[i] = copy_exprs(values[i]) end return PhiCNode(new_values) end return x end copy_exprargs(x::Array{Any,1}) = Any[copy_exprs(@inbounds x[i]) for i in 1:length(x)] @eval exprarray(head::Symbol, arg::Array{Any,1}) = $(Expr(:new, :Expr, :head, :arg)) # create copies of the CodeInfo definition, and any mutable fields function copy(c::CodeInfo) cnew = ccall(:jl_copy_code_info, Ref{CodeInfo}, (Any,), c) cnew.code = copy_exprargs(cnew.code) cnew.slotnames = copy(cnew.slotnames) cnew.slotflags = copy(cnew.slotflags) if cnew.slottypes !== nothing cnew.slottypes = copy(cnew.slottypes) end cnew.codelocs = copy(cnew.codelocs) cnew.linetable = copy(cnew.linetable::Union{Vector{Any},Vector{Core.LineInfoNode}}) cnew.ssaflags = copy(cnew.ssaflags) cnew.edges = cnew.edges === nothing ? nothing : copy(cnew.edges::Vector) ssavaluetypes = cnew.ssavaluetypes ssavaluetypes isa Vector{Any} && (cnew.ssavaluetypes = copy(ssavaluetypes)) return cnew end ==(x::Expr, y::Expr) = x.head === y.head && isequal(x.args, y.args) ==(x::QuoteNode, y::QuoteNode) = isequal(x.value, y.value) ==(stmt1::Core.PhiNode, stmt2::Core.PhiNode) = stmt1.edges == stmt2.edges && stmt1.values == stmt2.values """ macroexpand(m::Module, x; recursive=true) Take the expression `x` and return an equivalent expression with all macros removed (expanded) for executing in module `m`. The `recursive` keyword controls whether deeper levels of nested macros are also expanded. This is demonstrated in the example below: ```julia-repl julia> module M macro m1() 42 end macro m2() :(@m1()) end end M julia> macroexpand(M, :(@m2()), recursive=true) 42 julia> macroexpand(M, :(@m2()), recursive=false) :(#= REPL[16]:6 =# M.@m1) ``` """ function macroexpand(m::Module, @nospecialize(x); recursive=true) if recursive ccall(:jl_macroexpand, Any, (Any, Any), x, m) else ccall(:jl_macroexpand1, Any, (Any, Any), x, m) end end """ @macroexpand Return equivalent expression with all macros removed (expanded). There are differences between `@macroexpand` and [`macroexpand`](@ref). * While [`macroexpand`](@ref) takes a keyword argument `recursive`, `@macroexpand` is always recursive. For a non recursive macro version, see [`@macroexpand1`](@ref). * While [`macroexpand`](@ref) has an explicit `module` argument, `@macroexpand` always expands with respect to the module in which it is called. This is best seen in the following example: ```julia-repl julia> module M macro m() 1 end function f() (@macroexpand(@m), macroexpand(M, :(@m)), macroexpand(Main, :(@m)) ) end end M julia> macro m() 2 end @m (macro with 1 method) julia> M.f() (1, 1, 2) ``` With `@macroexpand` the expression expands where `@macroexpand` appears in the code (module `M` in the example). With `macroexpand` the expression expands in the module given as the first argument. """ macro macroexpand(code) return :(macroexpand($__module__, $(QuoteNode(code)), recursive=true)) end """ @macroexpand1 Non recursive version of [`@macroexpand`](@ref). """ macro macroexpand1(code) return :(macroexpand($__module__, $(QuoteNode(code)), recursive=false)) end ## misc syntax ## """ Core.eval(m::Module, expr) Evaluate an expression in the given module and return the result. """ Core.eval """ @inline Give a hint to the compiler that this function is worth inlining. Small functions typically do not need the `@inline` annotation, as the compiler does it automatically. By using `@inline` on bigger functions, an extra nudge can be given to the compiler to inline it. `@inline` can be applied immediately before a function definition or within a function body. ```julia # annotate long-form definition @inline function longdef(x) ... end # annotate short-form definition @inline shortdef(x) = ... # annotate anonymous function that a `do` block creates f() do @inline ... end ``` !!! compat "Julia 1.8" The usage within a function body requires at least Julia 1.8. --- @inline block Give a hint to the compiler that calls within `block` are worth inlining. ```julia # The compiler will try to inline `f` @inline f(...) # The compiler will try to inline `f`, `g` and `+` @inline f(...) + g(...) ``` !!! note A callsite annotation always has the precedence over the annotation applied to the definition of the called function: ```julia @noinline function explicit_noinline(args...) # body end let @inline explicit_noinline(args...) # will be inlined end ``` !!! note When there are nested callsite annotations, the innermost annotation has the precedence: ```julia @noinline let a0, b0 = ... a = @inline f(a0) # the compiler will try to inline this call b = f(b0) # the compiler will NOT try to inline this call return a, b end ``` !!! warning Although a callsite annotation will try to force inlining in regardless of the cost model, there are still chances it can't succeed in it. Especially, recursive calls can not be inlined even if they are annotated as `@inline`d. !!! compat "Julia 1.8" The callsite annotation requires at least Julia 1.8. """ macro inline(x) return annotate_meta_def_or_block(x, :inline) end """ @noinline Give a hint to the compiler that it should not inline a function. Small functions are typically inlined automatically. By using `@noinline` on small functions, auto-inlining can be prevented. `@noinline` can be applied immediately before a function definition or within a function body. ```julia # annotate long-form definition @noinline function longdef(x) ... end # annotate short-form definition @noinline shortdef(x) = ... # annotate anonymous function that a `do` block creates f() do @noinline ... end ``` !!! compat "Julia 1.8" The usage within a function body requires at least Julia 1.8. --- @noinline block Give a hint to the compiler that it should not inline the calls within `block`. ```julia # The compiler will try to not inline `f` @noinline f(...) # The compiler will try to not inline `f`, `g` and `+` @noinline f(...) + g(...) ``` !!! note A callsite annotation always has the precedence over the annotation applied to the definition of the called function: ```julia @inline function explicit_inline(args...) # body end let @noinline explicit_inline(args...) # will not be inlined end ``` !!! note When there are nested callsite annotations, the innermost annotation has the precedence: ```julia @inline let a0, b0 = ... a = @noinline f(a0) # the compiler will NOT try to inline this call b = f(b0) # the compiler will try to inline this call return a, b end ``` !!! compat "Julia 1.8" The callsite annotation requires at least Julia 1.8. --- !!! note If the function is trivial (for example returning a constant) it might get inlined anyway. """ macro noinline(x) return annotate_meta_def_or_block(x, :noinline) end """ @constprop setting [ex] Control the mode of interprocedural constant propagation for the annotated function. Two `setting`s are supported: - `@constprop :aggressive [ex]`: apply constant propagation aggressively. For a method where the return type depends on the value of the arguments, this can yield improved inference results at the cost of additional compile time. - `@constprop :none [ex]`: disable constant propagation. This can reduce compile times for functions that Julia might otherwise deem worthy of constant-propagation. Common cases are for functions with `Bool`- or `Symbol`-valued arguments or keyword arguments. `@constprop` can be applied immediately before a function definition or within a function body. ```julia # annotate long-form definition @constprop :aggressive function longdef(x) ... end # annotate short-form definition @constprop :aggressive shortdef(x) = ... # annotate anonymous function that a `do` block creates f() do @constprop :aggressive ... end ``` !!! compat "Julia 1.10" The usage within a function body requires at least Julia 1.10. """ macro constprop(setting, ex) sym = constprop_setting(setting) isa(ex, Expr) && return esc(pushmeta!(ex, sym)) throw(ArgumentError(LazyString("Bad expression `", ex, "` in `@constprop settings ex`"))) end macro constprop(setting) sym = constprop_setting(setting) return Expr(:meta, sym) end function constprop_setting(@nospecialize setting) isa(setting, QuoteNode) && (setting = setting.value) if setting === :aggressive return :aggressive_constprop elseif setting === :none return :no_constprop end throw(ArgumentError(LazyString("@constprop "), setting, "not supported")) end """ @assume_effects setting... [ex] Override the compiler's effect modeling for the given method or foreign call. `@assume_effects` can be applied immediately before a function definition or within a function body. It can also be applied immediately before a `@ccall` expression. !!! compat "Julia 1.8" Using `Base.@assume_effects` requires Julia version 1.8. # Examples ```jldoctest julia> Base.@assume_effects :terminates_locally function pow(x) # this :terminates_locally allows `pow` to be constant-folded res = 1 1 < x < 20 || error("bad pow") while x > 1 res *= x x -= 1 end return res end pow (generic function with 1 method) julia> code_typed() do pow(12) end 1-element Vector{Any}: CodeInfo( 1 ─ return 479001600 ) => Int64 julia> code_typed() do map((2,3,4)) do x # this :terminates_locally allows this anonymous function to be constant-folded Base.@assume_effects :terminates_locally res = 1 1 < x < 20 || error("bad pow") while x > 1 res *= x x -= 1 end return res end end 1-element Vector{Any}: CodeInfo( 1 ─ return (2, 6, 24) ) => Tuple{Int64, Int64, Int64} julia> Base.@assume_effects :total !:nothrow @ccall jl_type_intersection(Vector{Int}::Any, Vector{<:Integer}::Any)::Any Vector{Int64} (alias for Array{Int64, 1}) ``` !!! compat "Julia 1.10" The usage within a function body requires at least Julia 1.10. !!! warning Improper use of this macro causes undefined behavior (including crashes, incorrect answers, or other hard to track bugs). Use with care and only as a last resort if absolutely required. Even in such a case, you SHOULD take all possible steps to minimize the strength of the effect assertion (e.g., do not use `:total` if `:nothrow` would have been sufficient). In general, each `setting` value makes an assertion about the behavior of the function, without requiring the compiler to prove that this behavior is indeed true. These assertions are made for all world ages. It is thus advisable to limit the use of generic functions that may later be extended to invalidate the assumption (which would cause undefined behavior). The following `setting`s are supported. - `:consistent` - `:effect_free` - `:nothrow` - `:terminates_globally` - `:terminates_locally` - `:notaskstate` - `:inaccessiblememonly` - `:foldable` - `:removable` - `:total` # Extended help --- ## `:consistent` The `:consistent` setting asserts that for egal (`===`) inputs: - The manner of termination (return value, exception, non-termination) will always be the same. - If the method returns, the results will always be egal. !!! note This in particular implies that the method must not return a freshly allocated mutable object. Multiple allocations of mutable objects (even with identical contents) are not egal. !!! note The `:consistent`-cy assertion is made world-age wise. More formally, write ``fᵢ`` for the evaluation of ``f`` in world-age ``i``, then we require: ```math ∀ i, x, y: x ≡ y → fᵢ(x) ≡ fᵢ(y) ``` However, for two world ages ``i``, ``j`` s.t. ``i ≠ j``, we may have ``fᵢ(x) ≢ fⱼ(y)``. A further implication is that `:consistent` functions may not make their return value dependent on the state of the heap or any other global state that is not constant for a given world age. !!! note The `:consistent`-cy includes all legal rewrites performed by the optimizer. For example, floating-point fastmath operations are not considered `:consistent`, because the optimizer may rewrite them causing the output to not be `:consistent`, even for the same world age (e.g. because one ran in the interpreter, while the other was optimized). !!! note If `:consistent` functions terminate by throwing an exception, that exception itself is not required to meet the egality requirement specified above. --- ## `:effect_free` The `:effect_free` setting asserts that the method is free of externally semantically visible side effects. The following is an incomplete list of externally semantically visible side effects: - Changing the value of a global variable. - Mutating the heap (e.g. an array or mutable value), except as noted below - Changing the method table (e.g. through calls to eval) - File/Network/etc. I/O - Task switching However, the following are explicitly not semantically visible, even if they may be observable: - Memory allocations (both mutable and immutable) - Elapsed time - Garbage collection - Heap mutations of objects whose lifetime does not exceed the method (i.e. were allocated in the method and do not escape). - The returned value (which is externally visible, but not a side effect) The rule of thumb here is that an externally visible side effect is anything that would affect the execution of the remainder of the program if the function were not executed. !!! note The `:effect_free` assertion is made both for the method itself and any code that is executed by the method. Keep in mind that the assertion must be valid for all world ages and limit use of this assertion accordingly. --- ## `:nothrow` The `:nothrow` settings asserts that this method does not terminate abnormally (i.e. will either always return a value or never return). !!! note It is permissible for `:nothrow` annotated methods to make use of exception handling internally as long as the exception is not rethrown out of the method itself. !!! note `MethodErrors` and similar exceptions count as abnormal termination. --- ## `:terminates_globally` The `:terminates_globally` settings asserts that this method will eventually terminate (either normally or abnormally), i.e. does not loop indefinitely. !!! note This `:terminates_globally` assertion covers any other methods called by the annotated method. !!! note The compiler will consider this a strong indication that the method will terminate relatively *quickly* and may (if otherwise legal), call this method at compile time. I.e. it is a bad idea to annotate this setting on a method that *technically*, but not *practically*, terminates. --- ## `:terminates_locally` The `:terminates_locally` setting is like `:terminates_globally`, except that it only applies to syntactic control flow *within* the annotated method. It is thus a much weaker (and thus safer) assertion that allows for the possibility of non-termination if the method calls some other method that does not terminate. !!! note `:terminates_globally` implies `:terminates_locally`. --- ## `:notaskstate` The `:notaskstate` setting asserts that the method does not use or modify the local task state (task local storage, RNG state, etc.) and may thus be safely moved between tasks without observable results. !!! note The implementation of exception handling makes use of state stored in the task object. However, this state is currently not considered to be within the scope of `:notaskstate` and is tracked separately using the `:nothrow` effect. !!! note The `:notaskstate` assertion concerns the state of the *currently running task*. If a reference to a `Task` object is obtained by some other means that does not consider which task is *currently* running, the `:notaskstate` effect need not be tainted. This is true, even if said task object happens to be `===` to the currently running task. !!! note Access to task state usually also results in the tainting of other effects, such as `:effect_free` (if task state is modified) or `:consistent` (if task state is used in the computation of the result). In particular, code that is not `:notaskstate`, but is `:effect_free` and `:consistent` may still be dead-code-eliminated and thus promoted to `:total`. --- ## `:inaccessiblememonly` The `:inaccessiblememonly` setting asserts that the method does not access or modify externally accessible mutable memory. This means the method can access or modify mutable memory for newly allocated objects that is not accessible by other methods or top-level execution before return from the method, but it can not access or modify any mutable global state or mutable memory pointed to by its arguments. !!! note Below is an incomplete list of examples that invalidate this assumption: - a global reference or `getglobal` call to access a mutable global variable - a global assignment or `setglobal!` call to perform assignment to a non-constant global variable - `setfield!` call that changes a field of a global mutable variable !!! note This `:inaccessiblememonly` assertion covers any other methods called by the annotated method. --- ## `:foldable` This setting is a convenient shortcut for the set of effects that the compiler requires to be guaranteed to constant fold a call at compile time. It is currently equivalent to the following `setting`s: - `:consistent` - `:effect_free` - `:terminates_globally` !!! note This list in particular does not include `:nothrow`. The compiler will still attempt constant propagation and note any thrown error at compile time. Note however, that by the `:consistent`-cy requirements, any such annotated call must consistently throw given the same argument values. !!! note An explicit `@inbounds` annotation inside the function will also disable constant folding and not be overriden by `:foldable`. --- ## `:removable` This setting is a convenient shortcut for the set of effects that the compiler requires to be guaranteed to delete a call whose result is unused at compile time. It is currently equivalent to the following `setting`s: - `:effect_free` - `:nothrow` - `:terminates_globally` --- ## `:total` This `setting` is the maximum possible set of effects. It currently implies the following other `setting`s: - `:consistent` - `:effect_free` - `:nothrow` - `:terminates_globally` - `:notaskstate` - `:inaccessiblememonly` !!! warning `:total` is a very strong assertion and will likely gain additional semantics in future versions of Julia (e.g. if additional effects are added and included in the definition of `:total`). As a result, it should be used with care. Whenever possible, prefer to use the minimum possible set of specific effect assertions required for a particular application. In cases where a large number of effect overrides apply to a set of functions, a custom macro is recommended over the use of `:total`. --- ## Negated effects Effect names may be prefixed by `!` to indicate that the effect should be removed from an earlier meta effect. For example, `:total !:nothrow` indicates that while the call is generally total, it may however throw. """ macro assume_effects(args...) lastex = args[end] inner = unwrap_macrocalls(lastex) if is_function_def(inner) ex = lastex idx = length(args)-1 elseif isexpr(lastex, :macrocall) && lastex.args[1] === Symbol("@ccall") ex = lastex idx = length(args)-1 else # anonymous function case ex = nothing idx = length(args) end (consistent, effect_free, nothrow, terminates_globally, terminates_locally, notaskstate, inaccessiblememonly) = (false, false, false, false, false, false, false, false) for org_setting in args[1:idx] (setting, val) = compute_assumed_setting(org_setting) if setting === :consistent consistent = val elseif setting === :effect_free effect_free = val elseif setting === :nothrow nothrow = val elseif setting === :terminates_globally terminates_globally = val elseif setting === :terminates_locally terminates_locally = val elseif setting === :notaskstate notaskstate = val elseif setting === :inaccessiblememonly inaccessiblememonly = val elseif setting === :foldable consistent = effect_free = terminates_globally = val elseif setting === :removable effect_free = nothrow = terminates_globally = val elseif setting === :total consistent = effect_free = nothrow = terminates_globally = notaskstate = inaccessiblememonly = val else throw(ArgumentError("@assume_effects $org_setting not supported")) end end if is_function_def(inner) return esc(pushmeta!(ex, :purity, consistent, effect_free, nothrow, terminates_globally, terminates_locally, notaskstate, inaccessiblememonly)) elseif isexpr(ex, :macrocall) && ex.args[1] === Symbol("@ccall") ex.args[1] = GlobalRef(Base, Symbol("@ccall_effects")) insert!(ex.args, 3, Core.Compiler.encode_effects_override(Core.Compiler.EffectsOverride( consistent, effect_free, nothrow, terminates_globally, terminates_locally, notaskstate, inaccessiblememonly, ))) return esc(ex) else # anonymous function case return Expr(:meta, Expr(:purity, consistent, effect_free, nothrow, terminates_globally, terminates_locally, notaskstate, inaccessiblememonly)) end end function compute_assumed_setting(@nospecialize(setting), val::Bool=true) if isexpr(setting, :call) && setting.args[1] === :(!) return compute_assumed_setting(setting.args[2], !val) elseif isa(setting, QuoteNode) return compute_assumed_setting(setting.value, val) else return (setting, val) end end """ @propagate_inbounds Tells the compiler to inline a function while retaining the caller's inbounds context. """ macro propagate_inbounds(ex) if isa(ex, Expr) pushmeta!(ex, :inline) pushmeta!(ex, :propagate_inbounds) end esc(ex) end """ @polly Tells the compiler to apply the polyhedral optimizer Polly to a function. """ macro polly(ex) esc(isa(ex, Expr) ? pushmeta!(ex, :polly) : ex) end ## some macro utilities ## unwrap_macrocalls(@nospecialize(x)) = x function unwrap_macrocalls(ex::Expr) inner = ex while inner.head === :macrocall inner = inner.args[end]::Expr end return inner end function pushmeta!(ex::Expr, sym::Symbol, args::Any...) if isempty(args) tag = sym else tag = Expr(sym, args...)::Expr end inner = unwrap_macrocalls(ex) idx, exargs = findmeta(inner) if idx != 0 push!(exargs[idx].args, tag) else body = inner.args[2]::Expr pushfirst!(body.args, Expr(:meta, tag)) end ex end popmeta!(body, sym) = _getmeta(body, sym, true) peekmeta(body, sym) = _getmeta(body, sym, false) function _getmeta(body::Expr, sym::Symbol, delete::Bool) body.head === :block || return false, [] _getmeta(body.args, sym, delete) end _getmeta(arg, sym, delete::Bool) = (false, []) function _getmeta(body::Array{Any,1}, sym::Symbol, delete::Bool) idx, blockargs = findmeta_block(body, args -> findmetaarg(args,sym)!=0) if idx == 0 return false, [] end metaargs = blockargs[idx].args i = findmetaarg(blockargs[idx].args, sym) if i == 0 return false, [] end ret = isa(metaargs[i], Expr) ? (metaargs[i]::Expr).args : [] if delete deleteat!(metaargs, i) isempty(metaargs) && deleteat!(blockargs, idx) end true, ret end # Find index of `sym` in a meta expression argument list, or 0. function findmetaarg(metaargs, sym) for i = 1:length(metaargs) arg = metaargs[i] if (isa(arg, Symbol) && (arg::Symbol) == sym) || (isa(arg, Expr) && (arg::Expr).head == sym) return i end end return 0 end function annotate_meta_def_or_block(@nospecialize(ex), meta::Symbol) inner = unwrap_macrocalls(ex) if is_function_def(inner) # annotation on a definition return esc(pushmeta!(ex, meta)) else # annotation on a block return Expr(:block, Expr(meta, true), Expr(:local, Expr(:(=), :val, esc(ex))), Expr(meta, false), :val) end end function is_short_function_def(@nospecialize(ex)) isexpr(ex, :(=)) || return false while length(ex.args) >= 1 && isa(ex.args[1], Expr) (ex.args[1].head === :call) && return true (ex.args[1].head === :where || ex.args[1].head === :(::)) || return false ex = ex.args[1] end return false end is_function_def(@nospecialize(ex)) = return isexpr(ex, :function) || is_short_function_def(ex) || isexpr(ex, :->) function findmeta(ex::Expr) if is_function_def(ex) body = ex.args[2]::Expr body.head === :block || error(body, " is not a block expression") return findmeta_block(ex.args) end error(ex, " is not a function expression") end findmeta(ex::Array{Any,1}) = findmeta_block(ex) function findmeta_block(exargs, argsmatch=args->true) for i = 1:length(exargs) a = exargs[i] if isa(a, Expr) if a.head === :meta && argsmatch(a.args) return i, exargs elseif a.head === :block idx, exa = findmeta_block(a.args, argsmatch) if idx != 0 return idx, exa end end end end return 0, [] end remove_linenums!(ex) = ex function remove_linenums!(ex::Expr) if ex.head === :block || ex.head === :quote # remove line number expressions from metadata (not argument literal or inert) position filter!(ex.args) do x isa(x, Expr) && x.head === :line && return false isa(x, LineNumberNode) && return false return true end end for subex in ex.args subex isa Expr && remove_linenums!(subex) end return ex end function remove_linenums!(src::CodeInfo) src.codelocs .= 0 length(src.linetable) > 1 && resize!(src.linetable, 1) return src end replace_linenums!(ex, ln::LineNumberNode) = ex function replace_linenums!(ex::Expr, ln::LineNumberNode) if ex.head === :block || ex.head === :quote # replace line number expressions from metadata (not argument literal or inert) position map!(ex.args, ex.args) do @nospecialize(x) isa(x, Expr) && x.head === :line && length(x.args) == 1 && return Expr(:line, ln.line) isa(x, Expr) && x.head === :line && length(x.args) == 2 && return Expr(:line, ln.line, ln.file) isa(x, LineNumberNode) && return ln return x end end # preserve any linenums inside `esc(...)` guards if ex.head !== :escape for subex in ex.args subex isa Expr && replace_linenums!(subex, ln) end end return ex end macro generated() return Expr(:generated) end """ @generated f `@generated` is used to annotate a function which will be generated. In the body of the generated function, only types of arguments can be read (not the values). The function returns a quoted expression evaluated when the function is called. The `@generated` macro should not be used on functions mutating the global scope or depending on mutable elements. See [Metaprogramming](@ref) for further details. # Examples ```jldoctest julia> @generated function bar(x) if x <: Integer return :(x ^ 2) else return :(x) end end bar (generic function with 1 method) julia> bar(4) 16 julia> bar("baz") "baz" ``` """ macro generated(f) if isa(f, Expr) && (f.head === :function || is_short_function_def(f)) body = f.args[2] lno = body.args[1] tmp = gensym("tmp") return Expr(:escape, Expr(f.head, f.args[1], Expr(:block, lno, Expr(:if, Expr(:generated), body, Expr(:block, Expr(:meta, :generated_only), Expr(:return, nothing)))))) else error("invalid syntax; @generated must be used with a function definition") end end """ @atomic var @atomic order ex Mark `var` or `ex` as being performed atomically, if `ex` is a supported expression. @atomic a.b.x = new @atomic a.b.x += addend @atomic :release a.b.x = new @atomic :acquire_release a.b.x += addend Perform the store operation expressed on the right atomically and return the new value. With `=`, this operation translates to a `setproperty!(a.b, :x, new)` call. With any operator also, this operation translates to a `modifyproperty!(a.b, :x, +, addend)[2]` call. @atomic a.b.x max arg2 @atomic a.b.x + arg2 @atomic max(a.b.x, arg2) @atomic :acquire_release max(a.b.x, arg2) @atomic :acquire_release a.b.x + arg2 @atomic :acquire_release a.b.x max arg2 Perform the binary operation expressed on the right atomically. Store the result into the field in the first argument and return the values `(old, new)`. This operation translates to a `modifyproperty!(a.b, :x, func, arg2)` call. See [Per-field atomics](@ref man-atomics) section in the manual for more details. # Examples ```jldoctest julia> mutable struct Atomic{T}; @atomic x::T; end julia> a = Atomic(1) Atomic{Int64}(1) julia> @atomic a.x # fetch field x of a, with sequential consistency 1 julia> @atomic :sequentially_consistent a.x = 2 # set field x of a, with sequential consistency 2 julia> @atomic a.x += 1 # increment field x of a, with sequential consistency 3 julia> @atomic a.x + 1 # increment field x of a, with sequential consistency 3 => 4 julia> @atomic a.x # fetch field x of a, with sequential consistency 4 julia> @atomic max(a.x, 10) # change field x of a to the max value, with sequential consistency 4 => 10 julia> @atomic a.x max 5 # again change field x of a to the max value, with sequential consistency 10 => 10 ``` !!! compat "Julia 1.7" This functionality requires at least Julia 1.7. """ macro atomic(ex) if !isa(ex, Symbol) && !is_expr(ex, :(::)) return make_atomic(QuoteNode(:sequentially_consistent), ex) end return esc(Expr(:atomic, ex)) end macro atomic(order, ex) order isa QuoteNode || (order = esc(order)) return make_atomic(order, ex) end macro atomic(a1, op, a2) return make_atomic(QuoteNode(:sequentially_consistent), a1, op, a2) end macro atomic(order, a1, op, a2) order isa QuoteNode || (order = esc(order)) return make_atomic(order, a1, op, a2) end function make_atomic(order, ex) @nospecialize if ex isa Expr if isexpr(ex, :., 2) l, r = esc(ex.args[1]), esc(ex.args[2]) return :(getproperty($l, $r, $order)) elseif isexpr(ex, :call, 3) return make_atomic(order, ex.args[2], ex.args[1], ex.args[3]) elseif ex.head === :(=) l, r = ex.args[1], esc(ex.args[2]) if is_expr(l, :., 2) ll, lr = esc(l.args[1]), esc(l.args[2]) return :(setproperty!($ll, $lr, $r, $order)) end end if length(ex.args) == 2 if ex.head === :(+=) op = :+ elseif ex.head === :(-=) op = :- elseif @isdefined string shead = string(ex.head) if endswith(shead, '=') op = Symbol(shead[1:prevind(shead, end)]) end end if @isdefined(op) return Expr(:ref, make_atomic(order, ex.args[1], op, ex.args[2]), 2) end end end error("could not parse @atomic expression $ex") end function make_atomic(order, a1, op, a2) @nospecialize is_expr(a1, :., 2) || error("@atomic modify expression missing field access") a1l, a1r, op, a2 = esc(a1.args[1]), esc(a1.args[2]), esc(op), esc(a2) return :(modifyproperty!($a1l, $a1r, $op, $a2, $order)) end """ @atomicswap a.b.x = new @atomicswap :sequentially_consistent a.b.x = new Stores `new` into `a.b.x` and returns the old value of `a.b.x`. This operation translates to a `swapproperty!(a.b, :x, new)` call. See [Per-field atomics](@ref man-atomics) section in the manual for more details. # Examples ```jldoctest julia> mutable struct Atomic{T}; @atomic x::T; end julia> a = Atomic(1) Atomic{Int64}(1) julia> @atomicswap a.x = 2+2 # replace field x of a with 4, with sequential consistency 1 julia> @atomic a.x # fetch field x of a, with sequential consistency 4 ``` !!! compat "Julia 1.7" This functionality requires at least Julia 1.7. """ macro atomicswap(order, ex) order isa QuoteNode || (order = esc(order)) return make_atomicswap(order, ex) end macro atomicswap(ex) return make_atomicswap(QuoteNode(:sequentially_consistent), ex) end function make_atomicswap(order, ex) @nospecialize is_expr(ex, :(=), 2) || error("@atomicswap expression missing assignment") l, val = ex.args[1], esc(ex.args[2]) is_expr(l, :., 2) || error("@atomicswap expression missing field access") ll, lr = esc(l.args[1]), esc(l.args[2]) return :(swapproperty!($ll, $lr, $val, $order)) end """ @atomicreplace a.b.x expected => desired @atomicreplace :sequentially_consistent a.b.x expected => desired @atomicreplace :sequentially_consistent :monotonic a.b.x expected => desired Perform the conditional replacement expressed by the pair atomically, returning the values `(old, success::Bool)`. Where `success` indicates whether the replacement was completed. This operation translates to a `replaceproperty!(a.b, :x, expected, desired)` call. See [Per-field atomics](@ref man-atomics) section in the manual for more details. # Examples ```jldoctest julia> mutable struct Atomic{T}; @atomic x::T; end julia> a = Atomic(1) Atomic{Int64}(1) julia> @atomicreplace a.x 1 => 2 # replace field x of a with 2 if it was 1, with sequential consistency (old = 1, success = true) julia> @atomic a.x # fetch field x of a, with sequential consistency 2 julia> @atomicreplace a.x 1 => 2 # replace field x of a with 2 if it was 1, with sequential consistency (old = 2, success = false) julia> xchg = 2 => 0; # replace field x of a with 0 if it was 2, with sequential consistency julia> @atomicreplace a.x xchg (old = 2, success = true) julia> @atomic a.x # fetch field x of a, with sequential consistency 0 ``` !!! compat "Julia 1.7" This functionality requires at least Julia 1.7. """ macro atomicreplace(success_order, fail_order, ex, old_new) fail_order isa QuoteNode || (fail_order = esc(fail_order)) success_order isa QuoteNode || (success_order = esc(success_order)) return make_atomicreplace(success_order, fail_order, ex, old_new) end macro atomicreplace(order, ex, old_new) order isa QuoteNode || (order = esc(order)) return make_atomicreplace(order, order, ex, old_new) end macro atomicreplace(ex, old_new) return make_atomicreplace(QuoteNode(:sequentially_consistent), QuoteNode(:sequentially_consistent), ex, old_new) end function make_atomicreplace(success_order, fail_order, ex, old_new) @nospecialize is_expr(ex, :., 2) || error("@atomicreplace expression missing field access") ll, lr = esc(ex.args[1]), esc(ex.args[2]) if is_expr(old_new, :call, 3) && old_new.args[1] === :(=>) exp, rep = esc(old_new.args[2]), esc(old_new.args[3]) return :(replaceproperty!($ll, $lr, $exp, $rep, $success_order, $fail_order)) else old_new = esc(old_new) return :(replaceproperty!($ll, $lr, $old_new::Pair..., $success_order, $fail_order)) end end