Use disable_sigint instead of sigatomic_(begin|end)

[tkf]

close #684

[tkf]

So it seems that just switching to disable_sigint impedes Julia to inline ccalls. But we can avoid it with the optimization 6ca05f4 mentioned in JuliaLang/julia#29688.

Before 6ca05f4

julia> code_warntype(PyCall.__pycall!, (PyObject, PyPtr, PyObject, Ptr{Cvoid}); optimize=true)
Variables
  #self#::Core.Compiler.Const(PyCall.__pycall!, false)
  ret::PyObject
  pyargsptr::Ptr{PyCall.PyObject_struct}
  o::PyObject
  kw::Ptr{Nothing}
  #110::getfield(PyCall, Symbol("##110#111")){PyObject,Ptr{PyCall.PyObject_struct},PyObject,Ptr{Nothing}}

Body::PyObject
1 ─ %1 = %new(getfield(PyCall, Symbol("##110#111")){PyObject,Ptr{PyCall.PyObject_struct},PyObject,Ptr{Nothing}}, ret, pyargsptr, o, kw)::getfield(PyCall, Symbol("##110#111")){PyObject,Ptr{PyCall.PyObject_struct},PyObject,Ptr{Nothing}}
│        invoke PyCall.disable_sigint(%1::getfield(PyCall, Symbol("##110#111")){PyObject,Ptr{PyCall.PyObject_struct},PyObject,Ptr{Nothing}})
└──      return ret

After 6ca05f4

julia> code_warntype(PyCall.__pycall!, (PyObject, PyPtr, PyObject, Ptr{Cvoid}); optimize=true)
Variables
  #self#::Core.Compiler.Const(PyCall.__pycall!, false)
  ret::PyObject
  pyargsptr::Ptr{PyCall.PyObject_struct}
  o::PyObject
  kw::Ptr{Nothing}
  retptr::Ptr{PyCall.PyObject_struct}
  val::Ptr{PyCall.PyObject_struct}

Body::PyObject
1 ─       $(Expr(:foreigncall, :(:jl_sigatomic_begin), Nothing, svec(), :(:ccall), 0))
│   %2  = PyCall.getfield(o, :o)::Ptr{PyCall.PyObject_struct}
│   %3  = Base.bitcast(Ptr{PyCall.PyObject_struct}, kw)::Ptr{PyCall.PyObject_struct}
│   %4  = $(Expr(:foreigncall, :(Core.tuple(:PyObject_Call, PyCall.libpython)), Ptr{PyCall.PyObject_struct}, svec(Ptr{PyCall.PyObject_struct}, Ptr{PyCall.PyObject_struct}, Ptr{PyCall.PyObject_struct}), :(:ccall), 3, :(%2), :(pyargsptr), :(%3), :(kw), :(pyargsptr), :(o)))::Ptr{PyCall.PyObject_struct}
│   %5  = Core.bitcast(Core.UInt, %4)::UInt64
│   %6  = (%5 === 0x0000000000000000)::Bool
└──       goto #7 if not %6
2 ─ %8  = $(Expr(:foreigncall, :(Core.tuple(:PyErr_Occurred, PyCall.libpython)), Ptr{PyCall.PyObject_struct}, svec(), :(:ccall), 0))::Ptr{PyCall.PyObject_struct}
│   %9  = Core.bitcast(Core.UInt, %8)::UInt64
│   %10 = (%9 === 0x0000000000000000)::Bool
│   %11 = Base.not_int(%10)::Bool
└──       goto #4 if not %11
3 ─ %13 = invoke PyCall.PyError("\$(Expr(:escape, :(ccall(#= /home/takafumi/.julia/dev/PyCall/src/pyfncall.jl:43 =# @pysym(:PyObject_Call), PyPtr, (PyPtr, PyPtr, PyPtr), o, pyargsptr, kw))))"::String)::PyCall.PyError
│         PyCall.throw(%13)
└──       $(Expr(:unreachable))
4 ┄       goto #5
5 ─       goto #6
6 ─       invoke PyCall.error("\$(Expr(:escape, :(ccall(#= /home/takafumi/.julia/dev/PyCall/src/pyfncall.jl:43 =# @pysym(:PyObject_Call), PyPtr, (PyPtr, PyPtr, PyPtr), o, pyargsptr, kw))))"::String, " failed"::String)
└──       $(Expr(:unreachable))
7 ┄       invoke PyCall.pydecref_(_2::PyObject)
│         PyCall.setfield!(ret, :o, %4)
│         $(Expr(:foreigncall, :(:jl_sigatomic_end), Nothing, svec(), :(:ccall), 0))
└──       return ret

[stevengj]

What is the relationship of this PR to #574?

[tkf]

The first commit c030fdd in this PR is included in #574 but #574 comes with more "destructive" changes. This is a safe subset of #574.

The second commit 6ca05f4 is a fix for the possible performance regression (ccall not inlined) due to the first commit. I thought this might be appropriate given your comment #574 (comment).

[tkf]

AppVeyor failures are the same as #687. Merging...

I'm not using squash since each commit has distinct information.