_ _ _(_)_ | A fresh approach to technical computing
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| | |_| | | | (_| | | Version 0.7.0-DEV.3639 (2018-01-29 21:58 UTC)
_/ |\__'_|_|_|\__'_| | Commit 447ed272d4* (7 days old master)
|__/ | x86_64-apple-darwin16.7.0
julia> const unhex = [isxdigit(c) ? tryparse(UInt, "0x$c") : 0 for c in Char(1):Char(256)]
Unreachable reached at 0x10e004398
signal (4): Illegal instruction: 4
in expression starting at no file:0
collect_to! at ./array.jl:583
unknown function (ip: 0x10e004484)
jl_call_fptr_internal at /Users/sam/julia/julia/src/./julia_internal.h:383 [inlined]
jl_call_method_internal at /Users/sam/julia/julia/src/./julia_internal.h:402 [inlined]
jl_apply_generic at /Users/sam/julia/julia/src/gf.c:2089
collect_to! at ./array.jl:585
collect_to_with_first! at ./array.jl:562
unknown function (ip: 0x10e002f34)
jl_call_fptr_internal at /Users/sam/julia/julia/src/./julia_internal.h:383 [inlined]
jl_call_method_internal at /Users/sam/julia/julia/src/./julia_internal.h:402 [inlined]
jl_apply_generic at /Users/sam/julia/julia/src/gf.c:2089
collect at ./array.jl:543
unknown function (ip: 0x10e00110f)
jl_call_fptr_internal at /Users/sam/julia/julia/src/./julia_internal.h:383 [inlined]
jl_call_method_internal at /Users/sam/julia/julia/src/./julia_internal.h:402 [inlined]
jl_apply_generic at /Users/sam/julia/julia/src/gf.c:2089
do_call at /Users/sam/julia/julia/src/interpreter.c:323
eval_body at /Users/sam/julia/julia/src/interpreter.c:509
jl_interpret_toplevel_thunk_callback at /Users/sam/julia/julia/src/interpreter.c:720
unknown function (ip: 0xfffffffffffffffe)
unknown function (ip: 0x11872ad4f)
unknown function (ip: 0xb)
jl_interpret_toplevel_thunk at /Users/sam/julia/julia/src/interpreter.c:729
jl_toplevel_eval_flex at /Users/sam/julia/julia/src/toplevel.c:806
jl_toplevel_eval_in at /Users/sam/julia/julia/src/builtins.c:626
eval at ./boot.jl:295 [inlined]
eval at /Users/sam/julia/julia/usr/share/julia/site/v0.7/REPL/src/REPL.jl:3
jl_call_fptr_internal at /Users/sam/julia/julia/src/./julia_internal.h:383 [inlined]
jl_call_method_internal at /Users/sam/julia/julia/src/./julia_internal.h:402 [inlined]
jl_apply_generic at /Users/sam/julia/julia/src/gf.c:2089
eval_user_input at /Users/sam/julia/julia/usr/share/julia/site/v0.7/REPL/src/REPL.jl:82
jl_call_fptr_internal at /Users/sam/julia/julia/src/./julia_internal.h:383 [inlined]
jl_call_method_internal at /Users/sam/julia/julia/src/./julia_internal.h:402 [inlined]
jl_apply_generic at /Users/sam/julia/julia/src/gf.c:2089
macro expansion at /Users/sam/julia/julia/usr/share/julia/site/v0.7/REPL/src/REPL.jl:113 [inlined]
#29 at ./event.jl:92
jl_call_fptr_internal at /Users/sam/julia/julia/src/./julia_internal.h:383 [inlined]
jl_call_method_internal at /Users/sam/julia/julia/src/./julia_internal.h:402 [inlined]
jl_apply_generic at /Users/sam/julia/julia/src/gf.c:2089
jl_apply at /Users/sam/julia/julia/src/./julia.h:1523 [inlined]
start_task at /Users/sam/julia/julia/src/task.c:268
Allocations: 3154295 (Pool: 3152918; Big: 1377); GC: 6
Illegal instruction: 4
samoconnor
All 16 comments
As a datapoint, this works: [isxdigit(c) ? tryparse(UInt, "0x$c") : UInt(0) for c in Char(1):Char(256)] (note the UInt(0) instead of just 0)
martinholters
on 6 Feb 2018
Is crashing caused by type inference stuffs?
julia> @code_warntype f()
Variables:
Body:
begin
# meta: location REPL[15] f 2
# meta: location strings/unicode.jl isxdigit 561
goto 4
4:
5:
goto 7
7:
goto 9
9:
10:
goto 12
12:
goto 14
14:
# meta: pop location
goto 17
17:
# meta: pop location
return 0
end::Int64
julia> function f(c = Char(1))
isxdigit(c) ? tryparse(UInt, "0x$c") : 0
end
iblis17
on 6 Feb 2018
That looks ok, it's the result of constant-propagating the Char(1). @code_warntype f(Char(1)) shows the expected type-unstable function.
martinholters
on 6 Feb 2018
No idea why (I just randomly comment out something), but this patch solves this issue.
diff --git a/base/array.jl b/base/array.jl
index 3dbaa5957e..6b0da32d1b 100644
--- a/base/array.jl
+++ b/base/array.jl
@@ -575,7 +575,7 @@ function collect_to!(dest::AbstractArray{T}, itr, offs, st) where T
el, st = next(itr, st)
S = typeof(el)
if S === T || S <: T
- @inbounds dest[i] = el::T
+ @inbounds dest[i] = el
i += 1
else
R = promote_typejoin(T, S)
FWIW, https://github.com/JuliaLang/julia/pull/25828 doesn't make the crash disappear either (too bad!).
nalimilan
on 6 Feb 2018
@nalimilan I applied your patch from #25828
Performance is fine, and it did not crash.
diff --git a/base/array.jl b/base/array.jl
index 3dbaa5957e..93111a0c61 100644
--- a/base/array.jl
+++ b/base/array.jl
@@ -574,12 +574,13 @@ function collect_to!(dest::AbstractArray{T}, itr, offs, st) where T
while !done(itr, st)
el, st = next(itr, st)
S = typeof(el)
- if S === T || S <: T
- @inbounds dest[i] = el::T
+ if el isa T || typeof(el) === T
+ @inbounds dest[i] = el
i += 1
else
R = promote_typejoin(T, S)
I meant that #25828 on its own doesn't make any difference if you don't remove ::T in addition. But indeed we can also remove that assertion, and in my tests it doesn't make a performance difference either with the PR.
nalimilan
on 6 Feb 2018
I guess this should be all that's needed:
if el isa T
@inbounds dest[i] = el
I think inference should be able to figure out that el::T there, so no need for the type-assertion. (What good is the || typeof(el) === T to do, BTW?)
But the code as it is now also should not crash. So might be worthwhile figuring out what's wrong there.
martinholters
on 7 Feb 2018
What good is the || typeof(el) === T to do, BTW?
See https://github.com/JuliaLang/julia/pull/25828#discussion_r165004950.
But we should probably remove the ::T assertion given that it works around the bug and doesn't seem to introduce any performance regression.
nalimilan
on 7 Feb 2018
I tested el isa T vs el isa T || typeof(el) === T.
Performance is quite different.
iblis17
on 7 Feb 2018
That's interesting. But most probably unrelated. Meanwhile I've managed to come up with a fairly minimal reproducer for this issue's underlying bug:
julia> @noinline f() = let c=rand(1:2); c == 1 ? 0 : c == 2 ? UInt(0) : nothing; end # @noinline for uncluttered code_warntype output
f (generic function with 1 method)
julia> function foo!(dest::AbstractArray{Integer})
el = f()
dest[1] = el::Integer
return dest
end
foo! (generic function with 1 method)
julia> @code_warntype foo!(Vector{Integer}(uninitialized, 1))
Variables:
dest::Array{Integer,1}
el::Union{Nothing, Int64, UInt64}
Body:
begin
el::Union{Nothing, Int64, UInt64} = $(Expr(:invoke, MethodInstance for f(), :(Main.f)))::Union{Nothing, Int64, UInt64}
#= line 3 =#
Core.SSAValue(0) = (Core.typeassert)(el::Union{Nothing, Int64, UInt64}, Main.Integer)::Integer
# meta: location array.jl setindex! 689
(Base.arrayset)(true, dest::Array{Integer,1}, Core.SSAValue(0), 1)::Array{Integer,1}
# meta: pop location
#= line 4 =#
return dest::Array{Integer,1}
end::Array{Integer,1}
julia> foo!(Vector{Integer}(uninitialized, 1))
Unreachable reached at 0x7f2d95930f91
signal (4): Illegal instruction
in expression starting at no file:0
foo! at ./REPL[2]:3
jl_call_fptr_internal at /home/hol/Projects/julia-master/src/julia_internal.h:383 [inlined]
jl_call_method_internal at /home/hol/Projects/julia-master/src/julia_internal.h:402 [inlined]
jl_apply_generic at /home/hol/Projects/julia-master/src/gf.c:2089
do_call at /home/hol/Projects/julia-master/src/interpreter.c:323
# ...
Changing f() to be inferred as Union{Int64,Nothing} makes the crash go away, while the output of @code_warntype looks the same, except for the changed Union type, obviously. The output of @code_llvm (which I cannot really interpret), OTOH, looks rather different.
martinholters
on 7 Feb 2018
Addition: Not restricted to arrays; this crashes, too:
mutable struct Foo; x::Integer; end
@noinline f() = let c=rand(1:2); c == 1 ? 0 : c == 2 ? UInt(0) : nothing; end # @noinline for uncluttered code_warntype output
function foo!(dest)
el = f()
dest.x = el::Integer
end
foo!(Foo(1))
Even shorter:
versioninfo()
#Julia Version 0.7.0-DEV.3736
#Commit 4b1cf22f98* (2018-02-06 16:41 UTC)
@noinline f() = let c=rand(1:2); c == 1 ? 0 : c == 2 ? UInt(0) : nothing; end
function g()
el=f()
el::Integer
end
g();
#Illegal instruction (core dumped)
chethega
on 7 Feb 2018
A=Union{Int64, UInt64, Nothing}[1];
g(x)=x[1]::Integer
g(A)
#core dumped
edit: same for g(x)=x[1]::Number.
chethega
on 7 Feb 2018
A couple of observations:
- The
Unionhas to contain at least two subtypes ofInteger, at least one type that is not a subtype ofInteger, and only concrete types. - It's important that the type-asserted value is returned (or otherwise used);
g(x)=(x[1]::Integer; nothing)does not crash. - Setting
A[1]to1.0makesgthrow the expectedTypeError, no crash.
martinholters
on 7 Feb 2018
Bisection points at 88a4db258280af8b73329c78fcdefd3d8bb1b1cf, cc @vtjnash
martinholters
on 7 Feb 2018
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