Micro-optimizations that reduce dynamic dispatch (#243)

Author: timholy

src/construct.jl

@@ -209,7 +209,8 @@ function prepare_call(@nospecialize(f), allargs; enter_generated = false)
     elseif any(is_vararg_type, allargs)
         return nothing  # https://github.com/JuliaLang/julia/issues/30995
     end
-    argtypes = Tuple{map(_Typeof,allargs)...}
+    argtypesv = Any[_Typeof(a) for a in allargs]
+    argtypes = Tuple{argtypesv...}
     method = whichtt(argtypes)
     if method === nothing
         # Call it to generate the exact error
@@ -234,9 +235,10 @@ end
 function prepare_framedata(framecode, argvals::Vector{Any}, caller_will_catch_err::Bool=false)
     if isa(framecode.scope, Method)
         meth, src = framecode.scope::Method, framecode.src
+        slotnames = src.slotnames::Vector{Any}  # this is more strongly typed in julia.h than in jltypes.c
         ssavt = src.ssavaluetypes
         ng = isa(ssavt, Int) ? ssavt : length(ssavt::Vector{Any})
-        nargs = length(argvals)
+        nargs, meth_nargs = length(argvals), Int(meth.nargs)
         if !isempty(junk)
             olddata = first(junk)
             delete!(junk, olddata)
@@ -260,21 +262,21 @@ function prepare_framedata(framecode, argvals::Vector{Any}, caller_will_catch_er
             callargs = Any[]
             last_exception = Ref{Any}(nothing)
         end
-        for i = 1:meth.nargs
-            last_reference[framecode.src.slotnames[i]] = i
-            if meth.isva && i == meth.nargs
+        for i = 1:meth_nargs
+            last_reference[slotnames[i]::Symbol] = i
+            if meth.isva && i == meth_nargs
                 locals[i] = nargs < i ? Some{Any}(()) : (let i=i; Some{Any}(ntuple(k->argvals[i+k-1], nargs-i+1)); end)
                 break
             end
             locals[i] = nargs >= i ? Some{Any}(argvals[i]) : Some{Any}(())
         end
         # add local variables initially undefined
-        for i = (meth.nargs+1):length(src.slotnames)
+        for i = (meth_nargs+1):length(slotnames)
             locals[i] = nothing
         end
     else
         src = framecode.src
-        locals = Vector{Union{Nothing,Some{Any}}}(undef, length(src.slotflags))
+        locals = Vector{Union{Nothing,Some{Any}}}(undef, length(src.slotflags))  # src.slotflags is concretely typed, unlike slotnames
         fill!(locals, nothing)
         ssavalues = Vector{Any}(undef, length(src.code))
         sparams = Any[]

src/interpret.jl

@@ -327,8 +327,8 @@ function do_assignment!(frame, @nospecialize(lhs), @nospecialize(rhs))
         data.ssavalues[lhs.id] = rhs
     elseif isa(lhs, SlotNumber)
         data.locals[lhs.id] = Some{Any}(rhs)
-        data.last_reference[code.src.slotnames[lhs.id]] =
-            lhs.id
+        slotnames = code.src.slotnames::Vector{Any}
+        data.last_reference[slotnames[lhs.id]::Symbol] = lhs.id
     elseif isa(lhs, GlobalRef)
         Core.eval(lhs.mod, :($(lhs.name) = $(QuoteNode(rhs))))
     elseif isa(lhs, Symbol)
@@ -430,7 +430,7 @@ function step_expr!(@nospecialize(recurse), frame, @nospecialize(node), istoplev
                     throw(TypeError(nameof(frame), "if", Bool, node.args[1]))
                 end
                 if !arg
-                    return (frame.pc = node.args[2])
+                    return (frame.pc = node.args[2]::Int)
                 end
             elseif node.head == :enter
                 rhs = node.args[1]

src/localmethtable.jl

@@ -7,11 +7,11 @@ Return the framecode and environment for a call specified by `fargs = [f, args..
 `parentframecode` is the caller, and `idx` is the program-counter index.
 If possible, `framecode` will be looked up from the local method tables of `parentframe`.
 """
-function get_call_framecode(fargs, parentframe::FrameCode, idx::Int; enter_generated::Bool=false)
+function get_call_framecode(fargs::Vector{Any}, parentframe::FrameCode, idx::Int; enter_generated::Bool=false)
     nargs = length(fargs)  # includes f as the first "argument"
     # Determine whether we can look up the appropriate framecode in the local method table
     if isassigned(parentframe.methodtables, idx)  # if this is the first call, this may not yet be set
-        tme = tme1 = parentframe.methodtables[idx]
+        tme = tme1 = parentframe.methodtables[idx]::TypeMapEntry
         local tmeprev
         depth = 1
         while true

src/utils.jl

@@ -293,7 +293,8 @@ function locals(frame::Frame)
     vars = Variable[]
     data, code = frame.framedata, frame.framecode
     added = Set{Symbol}()
-    for sym in code.src.slotnames
+    slotnames = code.src.slotnames::Vector{Any}
+    for sym in slotnames
         sym ∈ added && continue
         idx = get(data.last_reference, sym, 0)
         idx == 0 && continue
@@ -381,4 +382,4 @@ function Base.display_error(io::IO, er, frame::Frame)
     printstyled(io, "ERROR: "; bold=true, color=Base.error_color())
     showerror(IOContext(io, :limit => true), er, frame)
     println(io)
-end
+end