Clean up meta expression detection/handling

base/inference.jl

@@ -1280,6 +1280,13 @@ widenconst(t::ANY) = t
 
 issubstate(a::VarState, b::VarState) = (a.typ ⊑ b.typ && a.undef <= b.undef)
 
+# Meta expression head, these generally can't be deleted even when they are
+# in a dead branch but can be ignored when analyzing uses/liveness.
+is_meta_expr_head(head::Symbol) =
+ (head === :inbounds || head === :boundscheck || head === :meta ||
+ head === :line)
+is_meta_expr(ex::Expr) = is_meta_expr_head(ex.head)
+
 function tmerge(typea::ANY, typeb::ANY)
  typea ⊑ typeb && return typeb
  typeb ⊑ typea && return typea
@@ -1389,9 +1396,7 @@ function find_ssavalue_uses(e::ANY, uses, line)
  elseif isa(e,Expr)
  b = e::Expr
  head = b.head
- if head === :line
- return
- end
+ is_meta_expr_head(head) && return
  if head === :(=)
  if isa(b.args[1],SSAValue)
  id = (b.args[1]::SSAValue).id+1
@@ -2032,7 +2037,7 @@ function eval_annotate(e::ANY, vtypes::ANY, sv::InferenceState, undefs, pass)
 
  e = e::Expr
  head = e.head
- if is(head,:line) || is(head,:const)
+ if is_meta_expr_head(head) || is(head,:const)
  return e
  elseif is(head,:(=))
  e.args[2] = eval_annotate(e.args[2], vtypes, sv, undefs, pass)
@@ -2048,12 +2053,6 @@ function eval_annotate(e::ANY, vtypes::ANY, sv::InferenceState, undefs, pass)
  return e
 end
 
-function expr_cannot_delete(ex::Expr)
- head = ex.head
- return (head === :inbounds || head === :boundscheck || head === :meta ||
- head === :line)
-end
-
 # annotate types of all symbols in AST
 function type_annotate!(linfo::LambdaInfo, states::Array{Any,1}, sv::ANY, nargs)
  nslots = length(states[1])
@@ -2082,7 +2081,7 @@ function type_annotate!(linfo::LambdaInfo, states::Array{Any,1}, sv::ANY, nargs)
  record_slot_type!(id, widenconst(states[i+1][id].typ), linfo.slottypes)
  end
  elseif optimize
- if ((isa(expr, Expr) && expr_cannot_delete(expr::Expr)) ||
+ if ((isa(expr, Expr) && is_meta_expr(expr::Expr)) ||
  isa(expr, LineNumberNode))
  i += 1
  continue
@@ -2154,9 +2153,10 @@ function substitute!(e::ANY, na, argexprs, spvals, offset)
  end
  if isa(e,Expr)
  e = e::Expr
- if e.head === :static_parameter
+ head = e.head
+ if head === :static_parameter
  return spvals[e.args[1]]
- elseif e.head !== :line
+ elseif !is_meta_expr_head(head)
  for i=1:length(e.args)
  e.args[i] = substitute!(e.args[i], na, argexprs, spvals, offset)
  end
@@ -2170,8 +2170,7 @@ function occurs_more(e::ANY, pred, n)
  if isa(e,Expr)
  e = e::Expr
  head = e.head
- (head === :line || head === :meta || head === :inbounds ||
- head === :boundscheck) && return 0
+ is_meta_expr_head(head) && return 0
  c = 0
  for a = e.args
  c += occurs_more(a, pred, n)
@@ -2256,8 +2255,7 @@ function effect_free(e::ANY, linfo::LambdaInfo, allow_volatile::Bool)
  elseif isa(e, Expr)
  e = e::Expr
  head = e.head
- if head === :static_parameter || head === :meta || head === :line ||
- head === :inbounds || head === :boundscheck
+ if head === :static_parameter || is_meta_expr_head(head)
  return true
  end
  ea = e.args
@@ -2729,7 +2727,7 @@ function inlineable(f::ANY, ft::ANY, e::Expr, atypes::Vector{Any}, sv::Inference
  end
 
  if !isempty(stmts)
- if all(stmt -> (isa(stmt,Expr) && stmt.head === :line) || isa(stmt, LineNumberNode) || stmt === nothing,
+ if all(stmt -> (isa(stmt, Expr) && is_meta_expr(stmt::Expr)) || isa(stmt, LineNumberNode) || stmt === nothing,
  stmts)
  empty!(stmts)
  else
@@ -2778,13 +2776,7 @@ function inline_ignore(ex::ANY)
  if isa(ex, LineNumberNode) || ex === nothing
  return true
  end
- if isa(ex, Expr)
- ex = ex::Expr
- head = ex.head
- return (head === :line || head === :meta || head === :inbounds ||
- head === :boundscheck)
- end
- return false
+ return isa(ex, Expr) && is_meta_expr(ex::Expr)
 end
 
 function inline_worthy(body::Expr, cost::Integer=1000) # precondition: 0 < cost; nominal cost = 1000
@@ -2811,7 +2803,7 @@ end
 ssavalue_increment(body::ANY, incr) = body
 ssavalue_increment(body::SSAValue, incr) = SSAValue(body.id + incr)
 function ssavalue_increment(body::Expr, incr)
- if body.head === :line
+ if is_meta_expr(body)
  return body
  end
  for i in 1:length(body.args)
@@ -3179,6 +3171,8 @@ function occurs_outside_getfield(linfo::LambdaInfo, e::ANY, sym::ANY,
  end
  if isa(e,Expr)
  e = e::Expr
+ head = e.head
+ is_meta_expr_head(head) && return false
  if is_known_call(e, getfield, linfo) && symequal(e.args[2],sym)
  idx = e.args[3]
  if isa(idx,QuoteNode) && (idx.value in field_names)
@@ -3189,11 +3183,11 @@ function occurs_outside_getfield(linfo::LambdaInfo, e::ANY, sym::ANY,
  end
  return true
  end
- if is(e.head,:(=))
+ if head === :(=)
  return occurs_outside_getfield(linfo, e.args[2], sym, sv,
  field_count, field_names)
  else
- if (e.head === :block && isa(sym, Slot) &&
+ if (head === :block && isa(sym, Slot) &&
  linfo.slotflags[(sym::Slot).id] & Slot_UsedUndef == 0)
  ignore_void = true
  else