snoopr ("snoop recompilations") to detect method invalidations

[timholy]

Also provide infrastructure analyze and explain these invalidations.

This is WIP and could break any time. But here's a demo (must be run on JuliaLang/julia#35768):

julia> using SnoopCompile

julia> invalidations = @snoopr using FixedPointNumbers
1159-element Array{Any,1}:
   MethodInstance for reduce_empty(::Base.BottomRF{typeof(max)}, ::Type{VersionNumber})
  1
   MethodInstance for reduce_empty_iter(::Base.BottomRF{typeof(max)}, ::Set{VersionNumber}, ::Base.HasEltype)
  2
   MethodInstance for reduce_empty_iter(::Base.BottomRF{typeof(max)}, ::Set{VersionNumber})
  3
   MethodInstance for foldl_impl(::Base.BottomRF{typeof(max)}, ::NamedTuple{(),Tuple{}}, ::Set{VersionNumber})
  4
   MethodInstance for mapfoldl_impl(::typeof(identity), ::typeof(max), ::NamedTuple{(),Tuple{}}, ::Set{VersionNumber})
  5
   MethodInstance for #mapfoldl#201(::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}, ::typeof(mapfoldl), ::typeof(identity), ::typeof(max), ::Set{VersionNumber})
  6
   MethodInstance for mapfoldl(::typeof(identity), ::typeof(max), ::Set{VersionNumber})
  7
   MethodInstance for #mapreduce#205(::Base.Iterators.Pairs{Union{},Union{},Tuple{},NamedTuple{(),Tuple{}}}, ::typeof(mapreduce), ::typeof(identity), ::typeof(max), ::Set{VersionNumber})
  8
   MethodInstance for mapreduce(::typeof(identity), ::typeof(max), ::Set{VersionNumber})
  9
   MethodInstance for maximum(::Set{VersionNumber})
 10
   MethodInstance for set_maximum_version_registry!(::Pkg.Types.Context, ::Pkg.Types.PackageSpec)
 11
   MethodInstance for collect_project!(::Pkg.Types.Context, ::Pkg.Types.PackageSpec, ::String, ::Dict{Base.UUID,Array{Pkg.Types.PackageSpec,1}})
 12
  ⋮
 24
   MethodInstance for #ensure_artifact_installed#42(::Pkg.BinaryPlatforms.Linux, ::Bool, ::Bool, ::typeof(Pkg.Artifacts.ensure_artifact_installed), ::String, ::Dict, ::String)
 24
   MethodInstance for #ensure_artifact_installed#42(::Pkg.BinaryPlatforms.Platform, ::Bool, ::Bool, ::typeof(Pkg.Artifacts.ensure_artifact_installed), ::String, ::Dict{String,Any}, ::String)
 24
   MethodInstance for #ensure_artifact_installed#42(::Pkg.BinaryPlatforms.Linux, ::Bool, ::Bool, ::typeof(Pkg.Artifacts.ensure_artifact_installed), ::String, ::Dict{String,Any}, ::String)
 24
   MethodInstance for (::Pkg.Artifacts.var"#download_artifact##kw")(::NamedTuple{(:verbose, :quiet_download),Tuple{Bool,Bool}}, ::typeof(Pkg.Artifacts.download_artifact), ::Base.SHA1, ::String, ::Union{Nothing, String})
 20
   MethodInstance for #download_verify#93(::Bool, ::Bool, ::Bool, ::typeof(Pkg.PlatformEngines.download_verify), ::String, ::String, ::String)
 13
   MethodInstance for install_archive(::Array{Pair{String,Bool},1}, ::Base.SHA1, ::String)
 13
   MethodInstance for (::Pkg.Operations.var"#54#57"{Bool,Pkg.Types.Context,Dict{Base.UUID,Array{String,1}},Channel{Any},Channel{Any}})()
 14
   MethodInstance for _searchindex(::AbstractString, ::AbstractChar, ::Int64)
  5
   MethodInstance for (::Type{T} where T<:AbstractChar)(::Int32)
  1
   MethodInstance for lowercase(::T) where T<:AbstractChar
  1
   MethodInstance for uppercase(::T) where T<:AbstractChar
  1
   (::Type{X})(x::Real) where X<:FixedPoint in FixedPointNumbers at /home/tim/.julia/packages/FixedPointNumbers/w2pxG/src/FixedPointNumbers.jl:51

julia> trees = invalidation_trees(invalidations)
5-element Array{Pair{Union{Method, Core.MethodInstance},SnoopCompile.Invalidations},1}:
                                   Defining one(::Type{X}) where X<:FixedPoint in FixedPointNumbers at /home/tim/.julia/packages/FixedPointNumbers/w2pxG/src/FixedPointNumbers.jl:94 invalidated:

instances: signature Tuple{typeof(one),Type{T} where T<:AbstractChar} triggered MethodInstance for oneunit(::Type{T} where T<:AbstractChar) (1 children)
tables: MethodInstance for zero(::Type{Int32}) (0 children)
        MethodInstance for <=(::Int32, ::Int64) (0 children)
        MethodInstance for reinterpret(::Type{Char}, ::UInt32) (0 children)
        MethodInstance for max(::Int32, ::Int32) (0 children)
        MethodInstance for +(::Float64, ::Int64) (0 children)
        MethodInstance for one(::Type{UInt64}) (0 children)

       Defining promote_rule(::Type{T}, ::Type{Tf}) where {T<:Normed, Tf<:AbstractFloat} in FixedPointNumbers at /home/tim/.julia/packages/FixedPointNumbers/w2pxG/src/normed.jl:310 invalidated:

tables: MethodInstance for ==(::Int64, ::Int64) (0 children)
        MethodInstance for ==(::Int32, ::Int64) (0 children)
        MethodInstance for ==(::Int32, ::Int32) (2 children)

                               Defining sizeof(::Type{X}) where X<:FixedPoint in FixedPointNumbers at /home/tim/.julia/packages/FixedPointNumbers/w2pxG/src/FixedPointNumbers.jl:100 invalidated:

tables: MethodInstance for min(::Int64, ::Int64) (0 children)
        MethodInstance for min(::Int32, ::Int32) (0 children)
        MethodInstance for /(::UInt64, ::Float64) (0 children)
        MethodInstance for *(::Float64, ::Int64) (0 children)
        MethodInstance for *(::UInt64, ::Float64) (0 children)
        MethodInstance for oneunit(::Int32) (0 children)
        MethodInstance for sizeof(::Type{T} where T) (31 children)

 Defining reduce_empty(::typeof(Base.add_sum), ::Type{F}) where F<:FixedPoint in FixedPointNumbers at /home/tim/.julia/packages/FixedPointNumbers/w2pxG/src/FixedPointNumbers.jl:222 invalidated:

instances: MethodInstance for reduce_empty(::Base.BottomRF{typeof(max)}, ::Type{VersionNumber}) (136 children)

                             Defining (::Type{X})(x::Real) where X<:FixedPoint in FixedPointNumbers at /home/tim/.julia/packages/FixedPointNumbers/w2pxG/src/FixedPointNumbers.jl:51 invalidated:

instances: signature Tuple{Type{T} where T<:Int64,Int64} triggered MethodInstance for convert(::Type{T}, ::Int64) where T<:Int64 (386 children)
tables: MethodInstance for Char(::Int64) (0 children)


julia> explain(trees[end])
New method: (::Type{X})(x::Real) where X<:FixedPoint in FixedPointNumbers at /home/tim/.julia/packages/FixedPointNumbers/w2pxG/src/FixedPointNumbers.jl:51
Invalidated:
  signature Tuple{Type{T} where T<:Int64,Int64}:
    intersection: Tuple{Type{Union{}},Int64}
    matching method Int64(x::Union{Bool, Int32, Int64, UInt32, UInt64, UInt8, Int128, Int16, Int8, UInt128, UInt16}) in Core at boot.jl:707
    matching method (::Type{T})(x::T) where T<:Number in Core at boot.jl:715
  386 direct and indirect descendants
  method table for MethodInstance for Char(::Int64)
    0 direct and indirect descendants

julia> explain(trees[end-1])
New method: reduce_empty(::typeof(Base.add_sum), ::Type{F}) where F<:FixedPoint in FixedPointNumbers at /home/tim/.julia/packages/FixedPointNumbers/w2pxG/src/FixedPointNumbers.jl:222
Invalidated:
    MethodInstance for reduce_empty(::Base.BottomRF{typeof(max)}, ::Type{VersionNumber})
  136 direct and indirect descendants

julia> explain(trees[end-2])
New method: sizeof(::Type{X}) where X<:FixedPoint in FixedPointNumbers at /home/tim/.julia/packages/FixedPointNumbers/w2pxG/src/FixedPointNumbers.jl:100
Invalidated:
  method table for MethodInstance for min(::Int64, ::Int64)
    0 direct and indirect descendants
  method table for MethodInstance for min(::Int32, ::Int32)
    0 direct and indirect descendants
  method table for MethodInstance for /(::UInt64, ::Float64)
    0 direct and indirect descendants
  method table for MethodInstance for *(::Float64, ::Int64)
    0 direct and indirect descendants
  method table for MethodInstance for *(::UInt64, ::Float64)
    0 direct and indirect descendants
  method table for MethodInstance for oneunit(::Int32)
    0 direct and indirect descendants
  method table for MethodInstance for sizeof(::Type{T} where T)
    31 direct and indirect descendants

[aminya]

Do we need to use Int32 here?

[timholy]

Not strictly necessary but that's the type that gets loaded into the returned array (in C, int == Int32).

[timholy]

OK, let's do this!