Revert "Revert "eliminate Undef and Top types. fixes #8631""

This reverts commit c631a08.

base/base.jl

@@ -271,7 +271,7 @@ call{T}(::Type{Array{T}}, m::Integer, n::Integer, o::Integer) =
 
 # TODO: possibly turn these into deprecations
 Array{T,N}(::Type{T}, d::NTuple{N,Int}) = Array{T}(d)
-Array(T::Type, d::Integer...)  = Array{T}(convert((Int...), d))
+Array{T}(::Type{T}, d::Integer...) = Array{T}(convert((Int...), d))
 Array{T}(::Type{T}, m::Integer) = Array{T}(m)
 Array{T}(::Type{T}, m::Integer,n::Integer) = Array{T}(m,n)
 Array{T}(::Type{T}, m::Integer,n::Integer,o::Integer) = Array{T}(m,n,o)

base/boot.jl

@@ -117,7 +117,7 @@ import Core.Intrinsics.ccall
 
 export
  # key types
- Any, DataType, Vararg, ANY, NTuple, Top,
+ Any, DataType, Vararg, ANY, NTuple,
  Tuple, Type, TypeConstructor, TypeName, TypeVar, Union, UnionType, Void,
  AbstractArray, DenseArray,
  # special objects

base/inference.jl

@@ -15,6 +15,7 @@ type StaticVarInfo
  vars::Array{Any,1} # names of args and locals
  gensym_types::Array{Any,1} # types of the GenSym's in this function
  label_counter::Int # index of the current highest label for this function
+ fedbackvars::ObjectIdDict
 end
 
 type EmptyCallStack
@@ -342,7 +343,7 @@ const getfield_tfunc = function (A, s0, name)
  return abstract_eval_constant(eval(A1,fld))
  end
  if s === Module
- return Top
+ return Any
  end
  if isType(s0)
  sp = s0.parameters[1]
@@ -939,9 +940,6 @@ end
 
 function abstract_eval_arg(a::ANY, vtypes::ANY, sv::StaticVarInfo)
  t = abstract_eval(a, vtypes, sv)
- if isa(a,Symbol) || isa(a,SymbolNode) || isa(a,GenSym)
- t = typeintersect(t,Any) # remove Undef
- end
  if isa(t,TypeVar) && t.lb == Bottom && isleaftype(t.ub)
  t = t.ub
  end
@@ -1018,19 +1016,18 @@ function abstract_eval(e::ANY, vtypes, sv::StaticVarInfo)
  abstract_eval(e.args[1], vtypes, sv)
  t = Any
  elseif is(e.head,:static_typeof)
- t0 = abstract_eval(e.args[1], vtypes, sv)
- # intersect with Any to remove Undef
- t = typeintersect(t0, Any)
+ var = e.args[1]
+ t = t0 = abstract_eval(var, vtypes, sv)
  if isa(t,DataType) && typeseq(t,t.name.primary)
  # remove unnecessary typevars
  t = t.name.primary
  end
- if is(t,Bottom) && Undef<:t0
- # the first time we see this statement the variable will probably
- # be Undef; return Bottom so this doesn't contribute to the type
- # we eventually pick.
- elseif is(t,Bottom)
- t = Type{Bottom}
+ if is(t,Bottom)
+ # if we haven't gotten fed-back type info yet, return Bottom. otherwise
+ # Bottom is the actual type of the variable, so return Type{Bottom}.
+ if haskey(sv.fedbackvars, var)
+  t = Type{Bottom}
+ end
  elseif isleaftype(t)
  t = Type{t}
  elseif isleaftype(inference_stack.types)
@@ -1059,7 +1056,7 @@ function abstract_eval(e::ANY, vtypes, sv::StaticVarInfo)
  else
  t = Any
  end
- if isa(t,TypeVar) && t.lb === Bottom
+ if isa(t,TypeVar)
  # no need to use a typevar as the type of an expression
  t = t.ub
  end
@@ -1082,30 +1079,20 @@ function abstract_eval_constant(x::ANY)
  return typeof(x)
 end
 
-# Undef is the static type of a value location (e.g. variable) that is
-# undefined. The corresponding run-time type is Bottom, since accessing an
-# undefined location is an error. A non-lvalue expression cannot have
-# type Undef, only Bottom.
-# typealias Top Union(Any,Undef)
-
 abstract_eval_global(s::Symbol) =
  abstract_eval_global((inference_stack::CallStack).mod, s)
 
 function abstract_eval_global(M, s::Symbol)
  if isconst(M,s)
  return abstract_eval_constant(eval(M,s))
  end
- if !isdefined(M,s)
- return Top
- end
- # TODO: change to Undef if there's a way to clear variables
  return Any
 end
 
 function abstract_eval_gensym(s::GenSym, sv::StaticVarInfo)
  typ = sv.gensym_types[s.id+1]
  if typ === NF
- return Undef
+ return Bottom
  end
  return typ
 end
@@ -1137,7 +1124,7 @@ function abstract_eval_symbol(s::Symbol, vtypes::ObjectIdDict, sv::StaticVarInfo
  end
  if s in sv.vars
  # local variable use not reached
- return Top
+ return Bottom
  end
  # global
  return abstract_eval_global(s)
@@ -1208,18 +1195,10 @@ function type_too_complex(t::ANY, d)
 end
 
 function tmerge(typea::ANY, typeb::ANY)
- if is(typea,NF)
- return typeb
- end
- if is(typeb,NF)
- return typea
- end
- if typea <: typeb
- return typeb
- end
- if typeb <: typea
- return typea
- end
+ is(typea, NF ) && return typeb
+ is(typeb, NF) && return typea
+ typea <: typeb && return typeb
+ typeb <: typea && return typea
  if isa(typea, Tuple) && isa(typeb, Tuple)
  if length(typea) == length(typeb) && !isvatuple(typea) && !isvatuple(typeb)
  return typejoin(typea, typeb)
@@ -1230,7 +1209,7 @@ function tmerge(typea::ANY, typeb::ANY)
  if length(u.types) > MAX_TYPEUNION_LEN || type_too_complex(u, 0)
  # don't let type unions get too big
  # TODO: something smarter, like a common supertype
- return Undef<:u ? Top : Any
+ return Any
  end
  return u
 end
@@ -1252,13 +1231,19 @@ function stupdate(state::ObjectIdDict, changes::Union(StateUpdate,VarTable), var
  state
 end
 
-function stchanged(new::Union(StateUpdate,VarTable), old, vars)
+function stchanged(new::Union(StateUpdate,VarTable), old, vinflist)
  if is(old,())
  return true
  end
- for i = 1:length(vars)
- v = vars[i]
- if tchanged(new[v], get(old,v,NF))
+ for vi in vinflist
+ v = vi[1]
+ newtype = new[v]
+ oldtype = get(old,v,NF)
+ if (newtype === Bottom && oldtype !== NF && oldtype !== Bottom) ||
+ (oldtype === Bottom && newtype !== NF && newtype !== Bottom)
+ vi[3] |= 32
+ end
+ if tchanged(newtype, oldtype)
  return true
  end
  end
@@ -1457,7 +1442,7 @@ function typeinf(linfo::LambdaStaticData,atypes::Tuple,sparams::Tuple, def, cop)
  # initial types
  s[1] = ObjectIdDict()
  for v in vars
- s[1][v] = Undef
+ s[1][v] = Bottom
  end
  if la > 0
  lastarg = ast.args[1][la]
@@ -1507,7 +1492,8 @@ function typeinf(linfo::LambdaStaticData,atypes::Tuple,sparams::Tuple, def, cop)
  cenv[vname] = vtype
  s[1][vname] = vtype
  end
- for vi = ((ast.args[2][2])::Array{Any,1})
+ vinflist = ast.args[2][2]::Array{Any,1}
+ for vi in vinflist
  vi::Array{Any,1}
  if (vi[3]&4)!=0
  # variables assigned by inner functions are treated like
@@ -1523,7 +1509,7 @@ function typeinf(linfo::LambdaStaticData,atypes::Tuple,sparams::Tuple, def, cop)
  gensym_init = Any[ NF for i = 1:length(gensym_uses) ]
  gensym_types = copy(gensym_init)
 
- sv = StaticVarInfo(sparams, cenv, vars, gensym_types, length(labels))
+ sv = StaticVarInfo(sparams, cenv, vars, gensym_types, length(labels), ObjectIdDict())
  frame.sv = sv
 
  recpts = IntSet() # statements that depend recursively on our value
@@ -1565,7 +1551,7 @@ function typeinf(linfo::LambdaStaticData,atypes::Tuple,sparams::Tuple, def, cop)
  if !is(cur_hand,())
  # propagate type info to exception handler
  l = cur_hand[1]::Int
- if stchanged(changes, s[l], vars)
+ if stchanged(changes, s[l], vinflist)
  push!(W, l)
  s[l] = stupdate(s[l], changes, vars)
  end
@@ -1598,7 +1584,7 @@ function typeinf(linfo::LambdaStaticData,atypes::Tuple,sparams::Tuple, def, cop)
  else
  # general case
  handler_at[l] = cur_hand
- if stchanged(changes, s[l], vars)
+ if stchanged(changes, s[l], vinflist)
  push!(W, l)
  s[l] = stupdate(s[l], changes, vars)
  end
@@ -1619,6 +1605,7 @@ function typeinf(linfo::LambdaStaticData,atypes::Tuple,sparams::Tuple, def, cop)
  gensym_init[id] = vt
  typegotoredo = true
  end
+ sv.fedbackvars[var] = true
  end
  elseif is(hd,:return)
  pc´ = n+1
@@ -1663,7 +1650,7 @@ function typeinf(linfo::LambdaStaticData,atypes::Tuple,sparams::Tuple, def, cop)
  end
  end
  if pc´<=n && (handler_at[pc´] = cur_hand; true) &&
- stchanged(changes, s[pc´], vars)
+ stchanged(changes, s[pc´], vinflist)
  s[pc´] = stupdate(s[pc´], changes, vars)
  pc = pc´
  elseif pc´ in W
@@ -1752,7 +1739,7 @@ function record_var_type(e::Symbol, t::ANY, decls)
  end
 end
 
-function eval_annotate(e::ANY, vtypes::ANY, sv::StaticVarInfo, decls, clo)
+function eval_annotate(e::ANY, vtypes::ANY, sv::StaticVarInfo, decls, clo, undefs)
  if isa(e, Symbol)
  e = e::Symbol
 
@@ -1761,13 +1748,19 @@ function eval_annotate(e::ANY, vtypes::ANY, sv::StaticVarInfo, decls, clo)
  return e
  end
  t = abstract_eval(e, vtypes, sv)
+ if t === Bottom
+ undefs[e] = true
+ end
  record_var_type(e, t, decls)
  return (is(t,Any) || is(t,IntrinsicFunction)) ? e : SymbolNode(e, t)
  end
 
  if isa(e, SymbolNode)
  e = e::SymbolNode
  curtype = e.typ
+ if curtype === Bottom
+ undefs[e.name] = true
+ end
  t = abstract_eval(e.name, vtypes, sv)
  if !(curtype <: t) || typeseq(curtype, t)
  record_var_type(e.name, t, decls)
@@ -1800,7 +1793,7 @@ function eval_annotate(e::ANY, vtypes::ANY, sv::StaticVarInfo, decls, clo)
  # we don't use types on assignment LHS
  s = s.name
  end
- e.args[2] = eval_annotate(e.args[2], vtypes, sv, decls, clo)
+ e.args[2] = eval_annotate(e.args[2], vtypes, sv, decls, clo, undefs)
  if isa(s,Symbol)
  # TODO: if this def does not reach any uses, maybe don't do this
  rhstype = exprtype(e.args[2], sv)
@@ -1814,7 +1807,7 @@ function eval_annotate(e::ANY, vtypes::ANY, sv::StaticVarInfo, decls, clo)
  for i=i0:length(e.args)
  subex = e.args[i]
  if !(isa(subex,Number) || isa(subex,AbstractString))
- e.args[i] = eval_annotate(subex, vtypes, sv, decls, clo)
+ e.args[i] = eval_annotate(subex, vtypes, sv, decls, clo, undefs)
  end
  end
  if (head === :call || head === :call1) && isa(e.args[1],LambdaStaticData)
@@ -1832,6 +1825,7 @@ end
 function type_annotate(ast::Expr, states::Array{Any,1}, sv::ANY, rettype::ANY,
  args)
  decls = ObjectIdDict()
+ undefs = ObjectIdDict()
  # initialize decls with argument types
  for arg in args
  decls[arg] = states[1][arg]
@@ -1842,7 +1836,7 @@ function type_annotate(ast::Expr, states::Array{Any,1}, sv::ANY, rettype::ANY,
  st_i = states[i]
  if st_i !== ()
  # st_i === () => unreached statement (see issue #7836)
- body[i] = eval_annotate(body[i], st_i, sv, decls, closures)
+ body[i] = eval_annotate(body[i], st_i, sv, decls, closures, undefs)
  end
  end
  ast.args[3].typ = rettype
@@ -1852,11 +1846,17 @@ function type_annotate(ast::Expr, states::Array{Any,1}, sv::ANY, rettype::ANY,
  if (vi[3]&4)==0
  vi[2] = get(decls, vi[1], vi[2])
  end
+ if haskey(undefs, vi[1])
+ vi[3] |= 32
+ end
  end
  for vi in ast.args[2][3]::Array{Any,1}
  if (vi[3]&4)==0
  vi[2] = get(decls, vi[1], vi[2])
  end
+ if haskey(undefs, vi[1])
+ vi[3] |= 32
+ end
  end
  ast.args[2][4] = sv.gensym_types
 
@@ -2350,7 +2350,6 @@ function inlineable(f::ANY, e::Expr, atypes::Tuple, sv::StaticVarInfo, enclosing
  for i = 1:numarg
  name = newnames[i]
  argtype = exprtype(argexprs[i],sv)
- argtype = typeintersect(argtype,Any) # remove Undef
  push!(locals, Any[name,argtype,0])
  push!(newcall.args, argtype===Any ? name : SymbolNode(name, argtype))
  end
@@ -3044,7 +3043,7 @@ function remove_redundant_temp_vars(ast, sa)
  # this transformation is not valid for vars used before def.
  # we need to preserve the point of assignment to know where to
  # throw errors (issue #4645).
- if !occurs_undef(v, ast.args[3])
+ if !occurs_undef(v, ast.args[3], varinfo)
 
  # the transformation is not ideal if the assignment
  # is present for the auto-unbox functionality
@@ -3063,18 +3062,22 @@ end
 
 function local_typeof(v, varinfo)
  for (v2, typ, info) in varinfo
- if v === v2
- return typ
- end
+ v === v2 && return typ
+ end
+ @assert false "v not in varinfo"
+end
+function var_infobits(v, varinfo)
+ for (v2, typ, info) in varinfo
+ v === v2 && return info
  end
  @assert false "v not in varinfo"
 end
 
-occurs_undef(var::GenSym, expr) = false
+occurs_undef(var::GenSym, expr, varinfo) = false
 
-occurs_undef(var, expr) =
- occurs_more(expr,
- e->(isa(e,SymbolNode) && symequal(var,e) && issubtype(Undef,e.typ)), 0)>0
+occurs_undef(var, expr, varinfo) =
+ occurs_more(expr, e->(isa(e,SymbolNode) && symequal(var,e) &&
+  ((var_infobits(e.name,varinfo)&32)!=0)), 0)>0
 
 # compute set of vars assigned once
 function find_sa_vars(ast)

base/serialize.jl

@@ -22,7 +22,7 @@ let i = 2
  UTF16String, UTF32String, Float16,
  :reserved9, :reserved10, :reserved11, :reserved12,
 
- (), Bool, Any, :Any, Bottom, Top, Undef, Type,
+ (), Bool, Any, :Any, Bottom, :reserved21, :reserved22, Type,
  :Array, :TypeVar, :Box,
  :lambda, :body, :return, :call, symbol("::"),
  :(=), :null, :gotoifnot, :A, :B, :C, :M, :N, :T, :S, :X, :Y,

base/show.jl

@@ -66,13 +66,7 @@ function show(io::IO, x::IntrinsicFunction)
  print(io, "(intrinsic function #", box(Int32,unbox(IntrinsicFunction,x)), ")")
 end
 
-function show(io::IO, x::UnionType)
- if is(x,Top)
- print(io, "Top")
- else
- print(io, "Union", x.types)
- end
-end
+show(io::IO, x::UnionType) = print(io, "Union", x.types)
 
 show(io::IO, x::TypeConstructor) = show(io, x.body)