我正在阅读涉及全局变量的this question about performance，并希望了解Julia如何翻译此代码。我意识到code_warntype不能以通常的方式在这里使用，因为代码不在函数中，并且将它包装在函数中会破坏练习的整个点。
是否存在@code_warntype的模拟或其他版本将直接采用一些Julia代码（例如，作为文件名，或作为普通字符串）并向我们显示该代码的类型化降级版本？或者可能是输出降低代码的命令行标志？ （似乎有用于生成LLVM代码或目标文件的标志，但没有用于输出只是推断和降低类型的代码。）
答案 0 :(得分：2)
您始终可以将有问题的代码包装到函数中并在其上调用@code_warntype。
以下是关联问题的示例：
n=5000;
x=rand(n)
y=rand(n)
mn=ones(n)*1000;
function foo()
for i in 1:n;
for j in 1:n;
c=abs(x[j]-y[i]);
if(c<mn[i])
mn[i]=c;
end
end
end
end
julia> @code_warntype foo()
Variables:
#temp#@_2::Any
i::Any
#temp#@_4::Any
j::Any
c::Any
Body:
begin
Core.SSAValue(0) = (1:Main.n)::Any
#temp#@_2::Any = (Base.start)(Core.SSAValue(0))::Any
3:
Core.SSAValue(1) = (Base.done)(Core.SSAValue(0), #temp#@_2::Any)::Any
Core.SSAValue(2) = (Core.typeassert)(Core.SSAValue(1), Core.Bool)::Bool
Core.SSAValue(3) = (Base.not_int)(Core.SSAValue(2))::Bool
unless Core.SSAValue(3) goto 37
Core.SSAValue(4) = (Base.next)(Core.SSAValue(0), #temp#@_2::Any)::Any
i::Any = (Core.getfield)(Core.SSAValue(4), 1)::Any
#temp#@_2::Any = (Core.getfield)(Core.SSAValue(4), 2)::Any
#= line 2 =#
Core.SSAValue(5) = (1:Main.n)::Any
#temp#@_4::Any = (Base.start)(Core.SSAValue(5))::Any
14:
Core.SSAValue(6) = (Base.done)(Core.SSAValue(5), #temp#@_4::Any)::Any
Core.SSAValue(7) = (Core.typeassert)(Core.SSAValue(6), Core.Bool)::Bool
Core.SSAValue(8) = (Base.not_int)(Core.SSAValue(7))::Bool
unless Core.SSAValue(8) goto 35
Core.SSAValue(9) = (Base.next)(Core.SSAValue(5), #temp#@_4::Any)::Any
j::Any = (Core.getfield)(Core.SSAValue(9), 1)::Any
#temp#@_4::Any = (Core.getfield)(Core.SSAValue(9), 2)::Any
#= line 3 =#
Core.SSAValue(10) = (Base.getindex)(Main.x, j::Any)::Any
Core.SSAValue(11) = (Base.getindex)(Main.y, i::Any)::Any
Core.SSAValue(12) = (Core.SSAValue(10) - Core.SSAValue(11))::Any
c::Any = (Main.abs)(Core.SSAValue(12))::Any
#= line 5 =#
Core.SSAValue(14) = (Base.getindex)(Main.mn, i::Any)::Any
Core.SSAValue(15) = (c::Any < Core.SSAValue(14))::Any
unless Core.SSAValue(15) goto 33
#= line 6 =#
(Base.setindex!)(Main.mn, c::Any, i::Any)::Any
33:
goto 14
35:
goto 3
37:
return
end::Nothing
将上述内容与
进行比较function foo()
n=5000;
x=rand(n)
y=rand(n)
mn=ones(n)*1000;
for i in 1:n;
for j in 1:n;
c=abs(x[j]-y[i]);
if(c<mn[i])
mn[i]=c;
end
end
end
end
julia> @code_warntype foo()
Variables:
n<optimized out>
x<optimized out>
y<optimized out>
mn::Array{Float64,1}
#temp#@_6::Int64
i<optimized out>
#temp#@_8::Int64
j<optimized out>
c<optimized out>
#temp#@_13::Bool
#temp#@_16::Bool
Body:
begin
#= line 3 =#
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/Random.jl rand 224
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/Random.jl rand 236
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/Random.jl rand 235
# meta: location boot.jl Type 397
# meta: location boot.jl Type 389
# meta: location boot.jl Type 380
Core.SSAValue(46) = $(Expr(:foreigncall, :(:jl_alloc_array_1d), Array{Float64,1}, svec(Any, Int64), :(:ccall), 2, Array{Float64,1}, 5000, 5000))
# meta: pop locations (3)
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/Random.jl rand! 214
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/RNGs.jl rand! 447
# meta: location array.jl length 137
Core.SSAValue(53) = (Base.arraylen)(Core.SSAValue(46))::Int64
# meta: pop location
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/RNGs.jl _rand! 440
# meta: location int.jl * 54
Core.SSAValue(66) = (Base.mul_int)(8, Core.SSAValue(53))::Int64
# meta: pop location
# meta: location array.jl length 137
Core.SSAValue(67) = (Base.arraylen)(Core.SSAValue(46))::Int64
# meta: pop location
# meta: location int.jl * 54
Core.SSAValue(68) = (Base.mul_int)(8, Core.SSAValue(67))::Int64
# meta: pop location
# meta: location int.jl <= 419
Core.SSAValue(69) = (Base.sle_int)(Core.SSAValue(66), Core.SSAValue(68))::Bool
# meta: pop location
unless Core.SSAValue(69) goto 31
#temp#@_13::Bool = true
goto 33
31:
#temp#@_13::Bool = false
33:
unless #temp#@_13::Bool goto 36
goto 41
36:
# meta: location boot.jl Type 281
Core.SSAValue(71) = $(Expr(:new, :(Core.AssertionError), "sizeof(Float64) * n64 <= sizeof(T) * length(A) && isbits(T)"))
# meta: pop location
(Base.throw)(Core.SSAValue(71))::Union{}
41:
#= line 441 =#
# meta: location gcutils.jl
#= line 81 =#
Core.SSAValue(61) = $(Expr(:gc_preserve_begin, Core.SSAValue(46)))
#= line 82 =#
# meta: location abstractarray.jl pointer 911
# meta: location pointer.jl unsafe_convert 65
Core.SSAValue(74) = $(Expr(:foreigncall, :(:jl_array_ptr), Ptr{Float64}, svec(Any), :(:ccall), 1, Core.SSAValue(46)))
# meta: pop locations (2)
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/RNGs.jl Type 365
Core.SSAValue(79) = $(Expr(:new, Random.UnsafeView{Float64}, Core.SSAValue(74), Core.SSAValue(53)))
# meta: pop location
$(Expr(:invoke, MethodInstance for rand!(::Random.MersenneTwister, ::Random.UnsafeView{Float64}, ::Random.SamplerTrivial{Random.CloseOpen01{Float64},Float64}), :(Random.rand!), :(Random.GLOBAL_RNG), Core.SSAValue(79), :($(QuoteNode(Random.SamplerTrivial{Random.CloseOpen01{Float64},Float64}(Random.CloseOpen01{Float64}()))))))::Random.UnsafeView{Float64}
#= line 83 =#
$(Expr(:gc_preserve_end, Core.SSAValue(61)))
# meta: pop locations (7)
#= line 4 =#
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/Random.jl rand 224
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/Random.jl rand 236
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/Random.jl rand 235
# meta: location boot.jl Type 397
# meta: location boot.jl Type 389
# meta: location boot.jl Type 380
Core.SSAValue(109) = $(Expr(:foreigncall, :(:jl_alloc_array_1d), Array{Float64,1}, svec(Any, Int64), :(:ccall), 2, Array{Float64,1}, 5000, 5000))
# meta: pop locations (3)
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/Random.jl rand! 214
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/RNGs.jl rand! 447
# meta: location array.jl length 137
Core.SSAValue(116) = (Base.arraylen)(Core.SSAValue(109))::Int64
# meta: pop location
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/RNGs.jl _rand! 440
# meta: location int.jl * 54
Core.SSAValue(129) = (Base.mul_int)(8, Core.SSAValue(116))::Int64
# meta: pop location
# meta: location array.jl length 137
Core.SSAValue(130) = (Base.arraylen)(Core.SSAValue(109))::Int64
# meta: pop location
# meta: location int.jl * 54
Core.SSAValue(131) = (Base.mul_int)(8, Core.SSAValue(130))::Int64
# meta: pop location
# meta: location int.jl <= 419
Core.SSAValue(132) = (Base.sle_int)(Core.SSAValue(129), Core.SSAValue(131))::Bool
# meta: pop location
unless Core.SSAValue(132) goto 88
#temp#@_16::Bool = true
goto 90
88:
#temp#@_16::Bool = false
90:
unless #temp#@_16::Bool goto 93
goto 98
93:
# meta: location boot.jl Type 281
Core.SSAValue(134) = $(Expr(:new, :(Core.AssertionError), "sizeof(Float64) * n64 <= sizeof(T) * length(A) && isbits(T)"))
# meta: pop location
(Base.throw)(Core.SSAValue(134))::Union{}
98:
#= line 441 =#
# meta: location gcutils.jl
#= line 81 =#
Core.SSAValue(124) = $(Expr(:gc_preserve_begin, Core.SSAValue(109)))
#= line 82 =#
# meta: location abstractarray.jl pointer 911
# meta: location pointer.jl unsafe_convert 65
Core.SSAValue(137) = $(Expr(:foreigncall, :(:jl_array_ptr), Ptr{Float64}, svec(Any), :(:ccall), 1, Core.SSAValue(109)))
# meta: pop locations (2)
# meta: location /buildworker/worker/package_linux64/build/usr/share/julia/site/v0.7/Random/src/RNGs.jl Type 365
Core.SSAValue(142) = $(Expr(:new, Random.UnsafeView{Float64}, Core.SSAValue(137), Core.SSAValue(116)))
# meta: pop location
$(Expr(:invoke, MethodInstance for rand!(::Random.MersenneTwister, ::Random.UnsafeView{Float64}, ::Random.SamplerTrivial{Random.CloseOpen01{Float64},Float64}), :(Random.rand!), :(Random.GLOBAL_RNG), Core.SSAValue(142), :($(QuoteNode(Random.SamplerTrivial{Random.CloseOpen01{Float64},Float64}(Random.CloseOpen01{Float64}()))))))::Random.UnsafeView{Float64}
#= line 83 =#
$(Expr(:gc_preserve_end, Core.SSAValue(124)))
# meta: pop locations (7)
#= line 5 =#
# meta: location array.jl ones 398
# meta: location array.jl ones 396
# meta: location array.jl ones 395
# meta: location boot.jl Type 389
# meta: location boot.jl Type 380
Core.SSAValue(170) = $(Expr(:foreigncall, :(:jl_alloc_array_1d), Array{Float64,1}, svec(Any, Int64), :(:ccall), 2, Array{Float64,1}, 5000, 5000))
# meta: pop locations (2)
Core.SSAValue(151) = $(Expr(:invoke, MethodInstance for fill!(::Array{Float64,1}, ::Float64), :(Base.fill!), Core.SSAValue(170), 1.0))::Array{Float64,1}
# meta: pop locations (3)
mn::Array{Float64,1} = $(Expr(:invoke, MethodInstance for *(::Array{Float64,1}, ::Int64), :(Main.:*), Core.SSAValue(151), 1000))::Array{Float64,1}
#= line 6 =#
#temp#@_6::Int64 = 1
128:
# meta: location range.jl done 457
# meta: location int.jl + 53
Core.SSAValue(197) = (Base.add_int)(5000, 1)::Int64
# meta: pop location
# meta: location promotion.jl == 433
Core.SSAValue(198) = (#temp#@_6::Int64 === Core.SSAValue(197))::Bool
# meta: pop locations (2)
Core.SSAValue(4) = (Base.not_int)(Core.SSAValue(198))::Bool
unless Core.SSAValue(4) goto 193
# meta: location range.jl next 456
# meta: location int.jl + 53
Core.SSAValue(203) = (Base.add_int)(#temp#@_6::Int64, 1)::Int64
# meta: pop location
Core.SSAValue(246) = #temp#@_6::Int64
# meta: pop location
#temp#@_6::Int64 = Core.SSAValue(203)
#= line 6 =#
#temp#@_8::Int64 = 1
147:
# meta: location range.jl done 457
# meta: location int.jl + 53
Core.SSAValue(229) = (Base.add_int)(5000, 1)::Int64
# meta: pop location
# meta: location promotion.jl == 433
Core.SSAValue(230) = (#temp#@_8::Int64 === Core.SSAValue(229))::Bool
# meta: pop locations (2)
Core.SSAValue(9) = (Base.not_int)(Core.SSAValue(230))::Bool
unless Core.SSAValue(9) goto 191
# meta: location range.jl next 456
# meta: location int.jl + 53
Core.SSAValue(235) = (Base.add_int)(#temp#@_8::Int64, 1)::Int64
# meta: pop location
Core.SSAValue(245) = #temp#@_8::Int64
# meta: pop location
#temp#@_8::Int64 = Core.SSAValue(235)
#= line 7 =#
# meta: location array.jl getindex 661
Core.SSAValue(236) = (Base.arrayref)(true, Core.SSAValue(46), Core.SSAValue(245))::Float64
# meta: pop location
# meta: location array.jl getindex 661
Core.SSAValue(237) = (Base.arrayref)(true, Core.SSAValue(109), Core.SSAValue(246))::Float64
# meta: pop location
# meta: location float.jl - 395
Core.SSAValue(238) = (Base.sub_float)(Core.SSAValue(236), Core.SSAValue(237))::Float64
# meta: pop location
# meta: location float.jl abs 517
Core.SSAValue(239) = (Base.abs_float)(Core.SSAValue(238))::Float64
# meta: pop location
#= line 9 =#
# meta: location array.jl getindex 661
Core.SSAValue(240) = (Base.arrayref)(true, mn::Array{Float64,1}, Core.SSAValue(246))::Float64
# meta: pop location
# meta: location float.jl < 450
Core.SSAValue(241) = (Base.lt_float)(Core.SSAValue(239), Core.SSAValue(240))::Bool
# meta: pop location
unless Core.SSAValue(241) goto 189
#= line 10 =#
# meta: location array.jl setindex! 699
(Base.arrayset)(true, mn::Array{Float64,1}, Core.SSAValue(239), Core.SSAValue(246))::Array{Float64,1}
# meta: pop location
189:
goto 147
191:
goto 128
193:
return
end::Nothing