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I'm not sure this blocks version 1.0. I agree we want it, but realistically it will take a bunch of time to settle and we know julia is perfectly usable without it. |
Is it that you think this will be very tricky to implement (understandably), or that you think the "no incest" rule will not be sufficient to make multiple inheritance sane? I would be willing to take a crack at this, but I'm afraid it may be beyond me. |
The first one. Everything in the type system is pretty fragile, hard to modify without unintended consequences. |
Ok, that's fair. I think I won't even attempt this then. Too hard and mucking about with the type system is definitely your expertise rather than mine. |
Maybe the no-incest rule in the initial suggestion can be weakened in a way similar to the following:
|
It seems to me that the no-incest rule presupposes that all descendents of
and then a user comes along and defines
It seems a bit harsh that this should invalidate the function
|
Another thought about multiple inheritance (which I am for) is that it seems like it could make things a lot trickier for type inference; the intersection of two abstract types would never be empty. If there were some kind of mechanism to specify that two types are disjoint (e.g., can not share a common descendent), that might help. |
The thinking here was that the |
@StefanKarpinski: That's very reasonable. My point was just that you cannot know at the time of the method definition for |
What about something like dominant and recessive alleles on biology http://en.wikipedia.org/wiki/Dominance_%28genetics%29 Indicate one abstract (parent) to have dominant alleles (methods) over the other (maybe the first on the list), and in case of redundancy choose the dominant. |
Hi there. I'm a new Julia user and multiple inheritance is important to me. Just adding my +1. |
Also, @diegozea's suggestion is basically what is done by Python's method resolution order (mro), which I have found very sensible. There is always the possibility of having multiple method name conflicts and wanting a different resolution for each one. In python, that situation is handled by the super method. |
In Gtk.jl (JuliaGraphics/Gtk.jl#20) there is also a need for inheriting from multiple interfaces. This might be faked by using type Unions but this has the drawback that the Union type cannot be extended. Therefore the question: Might it be possible to allow to extend Union types? Or is this almost the same as multiple inheritance and therefore the same effort to implement? @JeffBezanson, @StefanKarpinski |
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
This makes it much easier to spot dynamic dispatches: ```julia 3 ── %9 = (isa)(%4, @NamedTuple{x::Int64, y})::Bool └─── goto JuliaLang#5 if not %9 4 ── %11 = π (%4, @NamedTuple{x::Int64, y}) └─── goto JuliaLang#6 5 ── %13 = (Tuple{Int64, Any})(%4)::Tuple{Int64, Any} │ %14 = (getfield)(%13, 1)::Int64 │ %15 = (getfield)(%13, 2)::Any │ %16 = %new(@NamedTuple{x::Int64, y}, %14, %15)::@NamedTuple{x::Int64, y} ``` is now: ```julia 3 ── %9 = builtin (isa)(%4, @NamedTuple{x::Int64, y})::Bool └─── goto JuliaLang#5 if not %9 4 ── %11 = π (%4, @NamedTuple{x::Int64, y}) └─── goto JuliaLang#6 5 ── %13 = dynamic (Tuple{Int64, Any})(%4)::Tuple{Int64, Any} │ %14 = builtin (getfield)(%13, 1)::Int64 │ %15 = builtin (getfield)(%13, 2)::Any │ %16 = %new(@NamedTuple{x::Int64, y}, %14, %15)::@NamedTuple{x::Int64, y} ```
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
This makes it much easier to spot dynamic dispatches: ```julia 3 ── %9 = (isa)(%4, @NamedTuple{x::Int64, y})::Bool └─── goto JuliaLang#5 if not %9 4 ── %11 = π (%4, @NamedTuple{x::Int64, y}) └─── goto JuliaLang#6 5 ── %13 = (Tuple{Int64, Any})(%4)::Tuple{Int64, Any} │ %14 = (getfield)(%13, 1)::Int64 │ %15 = (getfield)(%13, 2)::Any │ %16 = %new(@NamedTuple{x::Int64, y}, %14, %15)::@NamedTuple{x::Int64, y} ``` is now: ```julia 3 ── %9 = builtin (isa)(%4, @NamedTuple{x::Int64, y})::Bool └─── goto JuliaLang#5 if not %9 4 ── %11 = π (%4, @NamedTuple{x::Int64, y}) └─── goto JuliaLang#6 5 ── %13 = dynamic (Tuple{Int64, Any})(%4)::Tuple{Int64, Any} │ %14 = builtin (getfield)(%13, 1)::Int64 │ %15 = builtin (getfield)(%13, 2)::Any │ %16 = %new(@NamedTuple{x::Int64, y}, %14, %15)::@NamedTuple{x::Int64, y} ```
Prior to this, especially on macOS, the gc-safepoint here would cause the process to segfault as we had already freed the current_task state. Rearrange this code so that the GC interactions (except for the atomic store to current_task) are all handled before entering GC safe, and then signaling the thread is deleted (via setting current_task = NULL, published by jl_unlock_profile_wr to other threads) is last. ``` ERROR: Exception handler triggered on unmanaged thread. Process 53827 stopped * thread #5, stop reason = EXC_BAD_ACCESS (code=2, address=0x100018008) frame #0: 0x0000000100b74344 libjulia-internal.1.12.0.dylib`jl_delete_thread [inlined] jl_gc_state_set(ptls=0x000000011f8b3200, state='\x02', old_state=<unavailable>) at julia_threads.h:272:9 [opt] 269 assert(old_state != JL_GC_CONCURRENT_COLLECTOR_THREAD); 270 jl_atomic_store_release(&ptls->gc_state, state); 271 if (state == JL_GC_STATE_UNSAFE || old_state == JL_GC_STATE_UNSAFE) -> 272 jl_gc_safepoint_(ptls); 273 return old_state; 274 } 275 STATIC_INLINE int8_t jl_gc_state_save_and_set(jl_ptls_t ptls, Target 0: (julia) stopped. (lldb) up frame #1: 0x0000000100b74320 libjulia-internal.1.12.0.dylib`jl_delete_thread [inlined] jl_gc_state_save_and_set(ptls=0x000000011f8b3200, state='\x02') at julia_threads.h:278:12 [opt] 275 STATIC_INLINE int8_t jl_gc_state_save_and_set(jl_ptls_t ptls, 276 int8_t state) 277 { -> 278 return jl_gc_state_set(ptls, state, jl_atomic_load_relaxed(&ptls->gc_state)); 279 } 280 #ifdef __clang_gcanalyzer__ 281 // these might not be a safepoint (if they are no-op safe=>safe transitions), but we have to assume it could be (statically) (lldb) frame #2: 0x0000000100b7431c libjulia-internal.1.12.0.dylib`jl_delete_thread(value=0x000000011f8b3200) at threading.c:537:11 [opt] 534 ptls->root_task = NULL; 535 jl_free_thread_gc_state(ptls); 536 // then park in safe-region -> 537 (void)jl_gc_safe_enter(ptls); 538 } ```
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
This makes it much easier to spot dynamic dispatches: ```julia 3 ── %9 = (isa)(%4, @NamedTuple{x::Int64, y})::Bool └─── goto JuliaLang#5 if not %9 4 ── %11 = π (%4, @NamedTuple{x::Int64, y}) └─── goto JuliaLang#6 5 ── %13 = (Tuple{Int64, Any})(%4)::Tuple{Int64, Any} │ %14 = (getfield)(%13, 1)::Int64 │ %15 = (getfield)(%13, 2)::Any │ %16 = %new(@NamedTuple{x::Int64, y}, %14, %15)::@NamedTuple{x::Int64, y} ``` is now: ```julia 3 ── %9 = builtin (isa)(%4, @NamedTuple{x::Int64, y})::Bool └─── goto JuliaLang#5 if not %9 4 ── %11 = π (%4, @NamedTuple{x::Int64, y}) └─── goto JuliaLang#6 5 ── %13 = dynamic (Tuple{Int64, Any})(%4)::Tuple{Int64, Any} │ %14 = builtin (getfield)(%13, 1)::Int64 │ %15 = builtin (getfield)(%13, 2)::Any │ %16 = %new(@NamedTuple{x::Int64, y}, %14, %15)::@NamedTuple{x::Int64, y} ``` This is on by default when displaying a CodeInfo, and off by default for `code_warntype`, unless optimize=true. Can be enabled / disabled via IRShowConfig.label_dynamic_calls
This makes it much easier to spot dynamic dispatches: ```julia 3 ── %9 = (isa)(%4, @NamedTuple{x::Int64, y})::Bool └─── goto JuliaLang#5 if not %9 4 ── %11 = π (%4, @NamedTuple{x::Int64, y}) └─── goto JuliaLang#6 5 ── %13 = (Tuple{Int64, Any})(%4)::Tuple{Int64, Any} │ %14 = (getfield)(%13, 1)::Int64 │ %15 = (getfield)(%13, 2)::Any │ %16 = %new(@NamedTuple{x::Int64, y}, %14, %15)::@NamedTuple{x::Int64, y} ``` is now: ```julia 3 ── %9 = builtin (isa)(%4, @NamedTuple{x::Int64, y})::Bool └─── goto JuliaLang#5 if not %9 4 ── %11 = π (%4, @NamedTuple{x::Int64, y}) └─── goto JuliaLang#6 5 ── %13 = dynamic (Tuple{Int64, Any})(%4)::Tuple{Int64, Any} │ %14 = builtin (getfield)(%13, 1)::Int64 │ %15 = builtin (getfield)(%13, 2)::Any │ %16 = %new(@NamedTuple{x::Int64, y}, %14, %15)::@NamedTuple{x::Int64, y} ``` This is on by default when displaying a CodeInfo, and off by default for `code_warntype`, unless optimize=true. Can be enabled / disabled via IRShowConfig.label_dynamic_calls
This makes it much easier to spot dynamic dispatches: ```julia 3 ── %9 = (isa)(%4, @NamedTuple{x::Int64, y})::Bool └─── goto JuliaLang#5 if not %9 4 ── %11 = π (%4, @NamedTuple{x::Int64, y}) └─── goto JuliaLang#6 5 ── %13 = (Tuple{Int64, Any})(%4)::Tuple{Int64, Any} │ %14 = (getfield)(%13, 1)::Int64 │ %15 = (getfield)(%13, 2)::Any │ %16 = %new(@NamedTuple{x::Int64, y}, %14, %15)::@NamedTuple{x::Int64, y} ``` is now: ```julia 3 ── %9 = builtin (isa)(%4, @NamedTuple{x::Int64, y})::Bool └─── goto JuliaLang#5 if not %9 4 ── %11 = π (%4, @NamedTuple{x::Int64, y}) └─── goto JuliaLang#6 5 ── %13 = dynamic (Tuple{Int64, Any})(%4)::Tuple{Int64, Any} │ %14 = builtin (getfield)(%13, 1)::Int64 │ %15 = builtin (getfield)(%13, 2)::Any │ %16 = %new(@NamedTuple{x::Int64, y}, %14, %15)::@NamedTuple{x::Int64, y} ``` This is on by default when displaying a CodeInfo, and off by default for `code_warntype`, unless optimize=true. Can be enabled / disabled via IRShowConfig.label_dynamic_calls
Prior to this, especially on macOS, the gc-safepoint here would cause the process to segfault as we had already freed the current_task state. Rearrange this code so that the GC interactions (except for the atomic store to current_task) are all handled before entering GC safe, and then signaling the thread is deleted (via setting current_task = NULL, published by jl_unlock_profile_wr to other threads) is last. ``` ERROR: Exception handler triggered on unmanaged thread. Process 53827 stopped * thread #5, stop reason = EXC_BAD_ACCESS (code=2, address=0x100018008) frame #0: 0x0000000100b74344 libjulia-internal.1.12.0.dylib`jl_delete_thread [inlined] jl_gc_state_set(ptls=0x000000011f8b3200, state='\x02', old_state=<unavailable>) at julia_threads.h:272:9 [opt] 269 assert(old_state != JL_GC_CONCURRENT_COLLECTOR_THREAD); 270 jl_atomic_store_release(&ptls->gc_state, state); 271 if (state == JL_GC_STATE_UNSAFE || old_state == JL_GC_STATE_UNSAFE) -> 272 jl_gc_safepoint_(ptls); 273 return old_state; 274 } 275 STATIC_INLINE int8_t jl_gc_state_save_and_set(jl_ptls_t ptls, Target 0: (julia) stopped. (lldb) up frame #1: 0x0000000100b74320 libjulia-internal.1.12.0.dylib`jl_delete_thread [inlined] jl_gc_state_save_and_set(ptls=0x000000011f8b3200, state='\x02') at julia_threads.h:278:12 [opt] 275 STATIC_INLINE int8_t jl_gc_state_save_and_set(jl_ptls_t ptls, 276 int8_t state) 277 { -> 278 return jl_gc_state_set(ptls, state, jl_atomic_load_relaxed(&ptls->gc_state)); 279 } 280 #ifdef __clang_gcanalyzer__ 281 // these might not be a safepoint (if they are no-op safe=>safe transitions), but we have to assume it could be (statically) (lldb) frame #2: 0x0000000100b7431c libjulia-internal.1.12.0.dylib`jl_delete_thread(value=0x000000011f8b3200) at threading.c:537:11 [opt] 534 ptls->root_task = NULL; 535 jl_free_thread_gc_state(ptls); 536 // then park in safe-region -> 537 (void)jl_gc_safe_enter(ptls); 538 } ``` (test incorporated into #55793)
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
Prior to this, especially on macOS, the gc-safepoint here would cause the process to segfault as we had already freed the current_task state. Rearrange this code so that the GC interactions (except for the atomic store to current_task) are all handled before entering GC safe, and then signaling the thread is deleted (via setting current_task = NULL, published by jl_unlock_profile_wr to other threads) is last. ``` ERROR: Exception handler triggered on unmanaged thread. Process 53827 stopped * thread JuliaLang#5, stop reason = EXC_BAD_ACCESS (code=2, address=0x100018008) frame #0: 0x0000000100b74344 libjulia-internal.1.12.0.dylib`jl_delete_thread [inlined] jl_gc_state_set(ptls=0x000000011f8b3200, state='\x02', old_state=<unavailable>) at julia_threads.h:272:9 [opt] 269 assert(old_state != JL_GC_CONCURRENT_COLLECTOR_THREAD); 270 jl_atomic_store_release(&ptls->gc_state, state); 271 if (state == JL_GC_STATE_UNSAFE || old_state == JL_GC_STATE_UNSAFE) -> 272 jl_gc_safepoint_(ptls); 273 return old_state; 274 } 275 STATIC_INLINE int8_t jl_gc_state_save_and_set(jl_ptls_t ptls, Target 0: (julia) stopped. (lldb) up frame JuliaLang#1: 0x0000000100b74320 libjulia-internal.1.12.0.dylib`jl_delete_thread [inlined] jl_gc_state_save_and_set(ptls=0x000000011f8b3200, state='\x02') at julia_threads.h:278:12 [opt] 275 STATIC_INLINE int8_t jl_gc_state_save_and_set(jl_ptls_t ptls, 276 int8_t state) 277 { -> 278 return jl_gc_state_set(ptls, state, jl_atomic_load_relaxed(&ptls->gc_state)); 279 } 280 #ifdef __clang_gcanalyzer__ 281 // these might not be a safepoint (if they are no-op safe=>safe transitions), but we have to assume it could be (statically) (lldb) frame JuliaLang#2: 0x0000000100b7431c libjulia-internal.1.12.0.dylib`jl_delete_thread(value=0x000000011f8b3200) at threading.c:537:11 [opt] 534 ptls->root_task = NULL; 535 jl_free_thread_gc_state(ptls); 536 // then park in safe-region -> 537 (void)jl_gc_safe_enter(ptls); 538 } ``` (test incorporated into JuliaLang#55793)
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible.
E.g. this allows `finalizer` inlining in the following case: ```julia mutable struct ForeignBuffer{T} const ptr::Ptr{T} end const foreign_buffer_finalized = Ref(false) function foreign_alloc(::Type{T}, length) where T ptr = Libc.malloc(sizeof(T) * length) ptr = Base.unsafe_convert(Ptr{T}, ptr) obj = ForeignBuffer{T}(ptr) return finalizer(obj) do obj Base.@assume_effects :notaskstate :nothrow foreign_buffer_finalized[] = true Libc.free(obj.ptr) end end function f_EA_finalizer(N::Int) workspace = foreign_alloc(Float64, N) GC.@preserve workspace begin (;ptr) = workspace Base.@assume_effects :nothrow @noinline println(devnull, "ptr = ", ptr) end end ``` ```julia julia> @code_typed f_EA_finalizer(42) CodeInfo( 1 ── %1 = Base.mul_int(8, N)::Int64 │ %2 = Core.lshr_int(%1, 63)::Int64 │ %3 = Core.trunc_int(Core.UInt8, %2)::UInt8 │ %4 = Core.eq_int(%3, 0x01)::Bool └─── goto #3 if not %4 2 ── invoke Core.throw_inexacterror(:convert::Symbol, UInt64::Type, %1::Int64)::Union{} └─── unreachable 3 ── goto #4 4 ── %9 = Core.bitcast(Core.UInt64, %1)::UInt64 └─── goto #5 5 ── goto #6 6 ── goto #7 7 ── goto #8 8 ── %14 = $(Expr(:foreigncall, :(:malloc), Ptr{Nothing}, svec(UInt64), 0, :(:ccall), :(%9), :(%9)))::Ptr{Nothing} └─── goto #9 9 ── %16 = Base.bitcast(Ptr{Float64}, %14)::Ptr{Float64} │ %17 = %new(ForeignBuffer{Float64}, %16)::ForeignBuffer{Float64} └─── goto #10 10 ─ %19 = $(Expr(:gc_preserve_begin, :(%17))) │ %20 = Base.getfield(%17, :ptr)::Ptr{Float64} │ invoke Main.println(Main.devnull::Base.DevNull, "ptr = "::String, %20::Ptr{Float64})::Nothing │ $(Expr(:gc_preserve_end, :(%19))) │ %23 = Main.foreign_buffer_finalized::Base.RefValue{Bool} │ Base.setfield!(%23, :x, true)::Bool │ %25 = Base.getfield(%17, :ptr)::Ptr{Float64} │ %26 = Base.bitcast(Ptr{Nothing}, %25)::Ptr{Nothing} │ $(Expr(:foreigncall, :(:free), Nothing, svec(Ptr{Nothing}), 0, :(:ccall), :(%26), :(%25)))::Nothing └─── return nothing ) => Nothing ``` However, this is still a WIP. Before merging, I want to improve EA's precision a bit and at least fix the test case that is currently marked as `broken`. I also need to check its impact on compiler performance. Additionally, I believe this feature is not yet practical. In particular, there is still significant room for improvement in the following areas: - EA's interprocedural capabilities: currently EA is performed ad-hoc for limited frames because of latency reasons, which significantly reduces its precision in the presence of interprocedural calls. - Relaxing the `:nothrow` check for finalizer inlining: the current algorithm requires `:nothrow`-ness on all paths from the allocation of the mutable struct to its last use, which is not practical for real-world cases. Even when `:nothrow` cannot be guaranteed, auxiliary optimizations such as inserting a `finalize` call after the last use might still be possible (#55990).
Prior to this, especially on macOS, the gc-safepoint here would cause the process to segfault as we had already freed the current_task state. Rearrange this code so that the GC interactions (except for the atomic store to current_task) are all handled before entering GC safe, and then signaling the thread is deleted (via setting current_task = NULL, published by jl_unlock_profile_wr to other threads) is last. ``` ERROR: Exception handler triggered on unmanaged thread. Process 53827 stopped * thread #5, stop reason = EXC_BAD_ACCESS (code=2, address=0x100018008) frame #0: 0x0000000100b74344 libjulia-internal.1.12.0.dylib`jl_delete_thread [inlined] jl_gc_state_set(ptls=0x000000011f8b3200, state='\x02', old_state=<unavailable>) at julia_threads.h:272:9 [opt] 269 assert(old_state != JL_GC_CONCURRENT_COLLECTOR_THREAD); 270 jl_atomic_store_release(&ptls->gc_state, state); 271 if (state == JL_GC_STATE_UNSAFE || old_state == JL_GC_STATE_UNSAFE) -> 272 jl_gc_safepoint_(ptls); 273 return old_state; 274 } 275 STATIC_INLINE int8_t jl_gc_state_save_and_set(jl_ptls_t ptls, Target 0: (julia) stopped. (lldb) up frame #1: 0x0000000100b74320 libjulia-internal.1.12.0.dylib`jl_delete_thread [inlined] jl_gc_state_save_and_set(ptls=0x000000011f8b3200, state='\x02') at julia_threads.h:278:12 [opt] 275 STATIC_INLINE int8_t jl_gc_state_save_and_set(jl_ptls_t ptls, 276 int8_t state) 277 { -> 278 return jl_gc_state_set(ptls, state, jl_atomic_load_relaxed(&ptls->gc_state)); 279 } 280 #ifdef __clang_gcanalyzer__ 281 // these might not be a safepoint (if they are no-op safe=>safe transitions), but we have to assume it could be (statically) (lldb) frame #2: 0x0000000100b7431c libjulia-internal.1.12.0.dylib`jl_delete_thread(value=0x000000011f8b3200) at threading.c:537:11 [opt] 534 ptls->root_task = NULL; 535 jl_free_thread_gc_state(ptls); 536 // then park in safe-region -> 537 (void)jl_gc_safe_enter(ptls); 538 } ``` (test incorporated into #55793) (cherry picked from commit 0d09f3d, resolving conflicts from not having backported #52198)
If a MethodError arises on a anonyomous function, the words "anonymous function" are printed in the error like so: ```julia g=(x,y)->x+y g(1,2,3) ``` ``` ERROR: MethodError: no method of the anonymous function var"#5#6" matching (::var"#5#6")(::Int64, ::Int64, ::Int64) The function `#5` exists, but no method is defined for this combination of argument types. Closest candidates are: (::var"#5#6")(::Any, ::Any) @ Main REPL[4]:1 ``` See the [original pull request](#57319) and [issue](#56325) #56325
Would it be possible to allow multiple inheritance for concrete types only? Meaning abstract type inheritance stays the same, but structs and primitive types can inherit multiple abstract types. In this case, almost all use cases for multiple inheritance will be covered (including interfaces) without introducing significant complexity (like loops) because concrete types are always final. The mechanism can be implemented by concatenating tables of whatever your internal representation of inheritance is for concrete types only so that conflicts (if any) will be resolved by giving preference to the type (method) that comes first in the list (like it's done in Python). |
I thought I had already replied on this issue, but maybe it was on another one.
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Fixes https://buildkite.com/julialang/julia-master/builds/46446#0195f712-1844-4e81-8b16-27b953fedcd3/899-1778 ``` | Error in testset Profile: | Test Failed at /cache/build/tester-amdci5-10/julialang/julia-master/julia-7c9af464cc/share/julia/stdlib/v1.13/Profile/test/runtests.jl:231 | Expression: occursin("@Compiler" * slash, str) | Evaluated: occursin("@Compiler/", "Overhead ╎ [+additional indent] Count File:Line Function\n=========================================================\n ╎9 @juliasrc/task.c:1249 start_task\n ╎ 9 @juliasrc/julia.h:2353 jl_apply\n ╎ 9 @juliasrc/gf.c:3693 ijl_apply_generic\n ╎ 9 @juliasrc/gf.c:3493 _jl_invoke\n ╎ 9 [unknown stackframe]\n ╎ 9 @Distributed/src/process_messages.jl:287 (::Distributed.var\"#handle_msg##2#handle_msg##3\"{Distributed.CallMsg{:call_fetch}, Distributed.MsgHeader, Sockets.TCPSocket})()\n ╎ ╎ 9 @Distributed/src/process_messages.jl:70 run_work_thunk(thunk::Distributed.var\"#handle_msg##4#handle_msg##5\"{Distributed.CallMsg{:call_fetch}}, print_error::Bool)\n ╎ ╎ 9 @Distributed/src/process_messages.jl:287 (::Distributed.var\"#handle_msg##4#handle_msg##5\"{Distributed.CallMsg{:call_fetch}})()\n ╎ ╎ 9 @juliasrc/builtins.c:841 jl_f__apply_iterate\n ╎ ╎ 9 @juliasrc/julia.h:2353 jl_apply\n ╎ ╎ 9 @juliasrc/gf.c:3693 ijl_apply_generic\n ╎ ╎ ╎ 9 @juliasrc/gf.c:3493 _jl_invoke\n ╎ ╎ ╎ 9 @Base/Base_compiler.jl:223 kwcall(::@NamedTuple{seed::UInt128}, ::typeof(invokelatest), ::Function, ::String, ::Vararg{String})\n ╎ ╎ ╎ 9 @juliasrc/builtins.c:841 jl_f__apply_iterate\n ╎ ╎ ╎ 9 @juliasrc/julia.h:2353 jl_apply\n ╎ ╎ ╎ 9 @juliasrc/gf.c:3693 ijl_apply_generic\n ╎ ╎ ╎ ╎ 9 @juliasrc/gf.c:3493 _jl_invoke\n ╎ ╎ ╎ ╎ 9 @juliasrc/builtins.c:853 jl_f_invokelatest\n ╎ ╎ ╎ ╎ 9 @juliasrc/julia.h:2353 jl_apply\n ╎ ╎ ╎ ╎ 9 @juliasrc/gf.c:3693 ijl_apply_generic\n ╎ ╎ ╎ ╎ 9 @juliasrc/gf.c:3493 _jl_invoke\n ╎ ╎ ╎ ╎ ╎ 9 [unknown stackframe]\n ╎ ╎ ╎ ╎ ╎ 9 /cache/build/tester-amdci5-10/julialang/julia-master/julia-7c9af464cc/share/julia/test/testdefs.jl:7 kwcall(::@NamedTuple{seed::UInt128}, ::typeof(runtests), name::String, path::String)\n ╎ ╎ ╎ ╎ ╎ 9 /cache/build/tester-amdci5-10/julialang/julia-master/julia-7c9af464cc/share/julia/test/testdefs.jl:7 runtests\n ╎ ╎ ╎ ╎ ╎ 9 /cache/build/tester-amdci5-10/julialang/julia-master/julia-7c9af464cc/share/julia/test/testdefs.jl:13 runtests(name::String, path::String, isolate::Bool; seed::UInt128)\n ╎ ╎ ╎ ╎ ╎ 9 @Base/env.jl:265 withenv(f::var\"#4#5\"{UInt128, String, String, Bool, Bool}, keyvals::Pair{String, Bool})\n ╎ ╎ ╎ ╎ ╎ ╎ 9 /cache/build/tester-amdci5-10/julialang/julia-master/julia-7c9af464cc/share/julia/test/testdefs.jl:27 (::var\"#4#5\"{UInt128, String, String, Bool, Bool})()\n ╎ ╎ ╎ ╎ ╎ ╎ 9 @Base/timing.jl:621 macro expansion\n ╎ ╎ ╎ ╎ ╎ ╎ 9 /cache/build/tester-amdci5-10/julialang/julia-master/julia-7c9af464cc/share/julia/test/testdefs.jl:29 macro expansion\n ╎ ╎ ╎ ╎ ╎ ╎ 9 @Test/src/Test.jl:1835 macro expansion\n ╎ ╎ ╎ ╎ ╎ ╎ 9 /cache/build/tester-amdci5-10/julialang/julia-master/julia-7c9af464cc/share/julia/test/testdefs.jl:37 macro expansion\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @Base/Base.jl:303 include(mod::Module, _path::String)\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @Base/loading.jl:2925 _include(mapexpr::Function, mod::Module, _path::String)\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/gf.c:3693 ijl_apply_generic\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/gf.c:3493 _jl_invoke\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @Base/loading.jl:2865 include_string(mapexpr::typeof(identity), mod::Module, code::String, filename::String)\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @Base/boot.jl:489 eval(m::Module, e::Any)\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/toplevel.c:1095 ijl_toplevel_eval_in\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/toplevel.c:1050 ijl_toplevel_eval\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/toplevel.c:978 jl_toplevel_eval_flex\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/toplevel.c:1038 jl_toplevel_eval_flex\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/interpreter.c:897 jl_interpret_toplevel_thunk\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/interpreter.c:557 eval_body\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/interpreter.c:557 eval_body\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/interpreter.c:557 eval_body\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/interpreter.c:692 eval_body\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/interpreter.c:193 eval_stmt_value\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/interpreter.c:242 eval_value\n ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ ╎ 9 @juliasrc/interpreter.c:124 do_call\n ╎ ╎ ╎ ╎ ... ```
In an email discussion we came to the conclusion that it made sense to have multiple inheritance in Julia with one fairly simple restriction:
This restriction, together with Julia not allowing inheritance from non-abstract types, seems to address all the practical issues one typically encounters with multiple inheritance. The following, for example, would be disallowed:
Note that a generic function is an object external to all types, not a name inside of a type as it would be in a traditional object-orientation language. Thus, one can have
f(a::A)
in one namespace andf(b::B)
in another namespace without problems, so long as thef
s in these two namespaces are distinct generic function objects.The text was updated successfully, but these errors were encountered: