improve many type stabilities in Core.Compiler.typeinf (#39549)

All of them are detected by JET.jl's self-profiling.
The following code will print type-instabilities/type-errors for all
code paths reachable from `typeinf(::NativeInterpreter, ::InferenceState)`.
```julia
julia> using JET
julia> report_call(Core.Compiler.typeinf,
(Core.Compiler.NativeInterpreter, Core.Compiler.InferenceState);
annotate_types = true)
```

The remaining error reports (e.g. `variable Core.Compiler.string is not
defined`) are because of missing functionality on error paths.

base/compiler/abstractinterpretation.jl

@@ -459,7 +459,7 @@ function abstract_call_method(interp::AbstractInterpreter, method::Method, @nosp
             # Under direct self-recursion, permit much greater use of reducers.
             # here we assume that complexity(specTypes) :>= complexity(sig)
             comparison = sv.linfo.specTypes
-            l_comparison = length(unwrap_unionall(comparison).parameters)
+            l_comparison = length(unwrap_unionall(comparison).parameters)::Int
             spec_len = max(spec_len, l_comparison)
         else
             comparison = method.sig
@@ -700,16 +700,20 @@ function abstract_apply(interp::AbstractInterpreter, @nospecialize(itft), @nospe
     res = Union{}
     nargs = length(aargtypes)
     splitunions = 1 < unionsplitcost(aargtypes) <= InferenceParams(interp).MAX_APPLY_UNION_ENUM
-    ctypes = Any[Any[aft]]
+    ctypes = [Any[aft]]
     infos = [Union{Nothing, AbstractIterationInfo}[]]
     for i = 1:nargs
-        ctypes´ = []
-        infos′ = []
+        ctypes´ = Vector{Any}[]
+        infos′ = Vector{Union{Nothing, AbstractIterationInfo}}[]
         for ti in (splitunions ? uniontypes(aargtypes[i]) : Any[aargtypes[i]])
             if !isvarargtype(ti)
-                cti, info = precise_container_type(interp, itft, ti, sv)
+                cti_info = precise_container_type(interp, itft, ti, sv)
+                cti = cti_info[1]::Vector{Any}
+                info = cti_info[2]::Union{Nothing,AbstractIterationInfo}
             else
-                cti, info = precise_container_type(interp, itft, unwrapva(ti), sv)
+                cti_info = precise_container_type(interp, itft, unwrapva(ti), sv)
+                cti = cti_info[1]::Vector{Any}
+                info = cti_info[2]::Union{Nothing,AbstractIterationInfo}
                 # We can't represent a repeating sequence of the same types,
                 # so tmerge everything together to get one type that represents
                 # everything.
@@ -726,7 +730,7 @@ function abstract_apply(interp::AbstractInterpreter, @nospecialize(itft), @nospe
                 continue
             end
             for j = 1:length(ctypes)
-                ct = ctypes[j]
+                ct = ctypes[j]::Vector{Any}
                 if isvarargtype(ct[end])
                     # This is vararg, we're not gonna be able to do any inling,
                     # drop the info
@@ -850,7 +854,8 @@ function abstract_call_builtin(interp::AbstractInterpreter, f::Builtin, fargs::U
        (a3 = argtypes[3]; isa(a3, Const)) && (idx = a3.val; isa(idx, Int)) &&
        (a2 = argtypes[2]; a2 ⊑ Tuple)
         # TODO: why doesn't this use the getfield_tfunc?
-        cti, _ = precise_container_type(interp, iterate, a2, sv)
+        cti_info = precise_container_type(interp, iterate, a2, sv)
+        cti = cti_info[1]::Vector{Any}
         if 1 <= idx <= length(cti)
             rt = unwrapva(cti[idx])
         end
@@ -1392,7 +1397,8 @@ function typeinf_local(interp::AbstractInterpreter, frame::InferenceState)
             delete!(W, pc)
             frame.currpc = pc
             frame.cur_hand = frame.handler_at[pc]
-            frame.stmt_edges[pc] === nothing || empty!(frame.stmt_edges[pc])
+            edges = frame.stmt_edges[pc]
+            edges === nothing || empty!(edges)
             stmt = frame.src.code[pc]
             changes = s[pc]::VarTable
             t = nothing
@@ -1405,7 +1411,7 @@ function typeinf_local(interp::AbstractInterpreter, frame::InferenceState)
             elseif isa(stmt, GotoNode)
                 pc´ = (stmt::GotoNode).label
             elseif isa(stmt, GotoIfNot)
-                condt = abstract_eval_value(interp, stmt.cond, s[pc], frame)
+                condt = abstract_eval_value(interp, stmt.cond, changes, frame)
                 if condt === Bottom
                     empty!(frame.pclimitations)
                 end
@@ -1438,7 +1444,7 @@ function typeinf_local(interp::AbstractInterpreter, frame::InferenceState)
                         end
                     end
                     newstate_else = stupdate!(s[l], changes_else)
-                    if newstate_else !== false
+                    if newstate_else !== nothing
                         # add else branch to active IP list
                         if l < frame.pc´´
                             frame.pc´´ = l
@@ -1449,7 +1455,7 @@ function typeinf_local(interp::AbstractInterpreter, frame::InferenceState)
                 end
             elseif isa(stmt, ReturnNode)
                 pc´ = n + 1
-                rt = widenconditional(abstract_eval_value(interp, stmt.val, s[pc], frame))
+                rt = widenconditional(abstract_eval_value(interp, stmt.val, changes, frame))
                 if !isa(rt, Const) && !isa(rt, Type) && !isa(rt, PartialStruct) && !isa(rt, PartialOpaque)
                     # only propagate information we know we can store
                     # and is valid inter-procedurally
@@ -1483,9 +1489,8 @@ function typeinf_local(interp::AbstractInterpreter, frame::InferenceState)
                 frame.cur_hand = Pair{Any,Any}(l, frame.cur_hand)
                 # propagate type info to exception handler
                 old = s[l]
-                new = s[pc]::VarTable
-                newstate_catch = stupdate!(old, new)
-                if newstate_catch !== false
+                newstate_catch = stupdate!(old, changes)
+                if newstate_catch !== nothing
                     if l < frame.pc´´
                         frame.pc´´ = l
                     end
@@ -1556,12 +1561,12 @@ function typeinf_local(interp::AbstractInterpreter, frame::InferenceState)
                 # (such as a terminator for a loop, if-else, or try block),
                 # consider whether we should jump to an older backedge first,
                 # to try to traverse the statements in approximate dominator order
-                if newstate !== false
+                if newstate !== nothing
                     s[pc´] = newstate
                 end
                 push!(W, pc´)
                 pc = frame.pc´´
-            elseif newstate !== false
+            elseif newstate !== nothing
                 s[pc´] = newstate
                 pc = pc´
             elseif pc´ in W

base/compiler/optimize.jl

@@ -371,7 +371,7 @@ function statement_cost(ex::Expr, line::Int, src::CodeInfo, sptypes::Vector{Any}
         end
         a = ex.args[2]
         if a isa Expr
-            cost = plus_saturate(cost, statement_cost(a, -1, src, sptypes, slottypes, params, error_path))
+            cost = plus_saturate(cost, statement_cost(a, -1, src, sptypes, slottypes, union_penalties, params, error_path))
         end
         return cost
     elseif head === :copyast
@@ -392,7 +392,7 @@ function statement_or_branch_cost(@nospecialize(stmt), line::Int, src::CodeInfo,
     thiscost = 0
     if stmt isa Expr
         thiscost = statement_cost(stmt, line, src, sptypes, slottypes, union_penalties, params,
-                                  params.unoptimize_throw_blocks && line in throw_blocks)::Int
+                                  throw_blocks !== nothing && line in throw_blocks)::Int
     elseif stmt isa GotoNode
         # loops are generally always expensive
         # but assume that forward jumps are already counted for from

base/compiler/ssair/driver.jl

@@ -43,13 +43,14 @@ function convert_to_ircode(ci::CodeInfo, code::Vector{Any}, coverage::Bool, narg
     labelmap = coverage ? fill(0, length(code)) : changemap
     prevloc = zero(eltype(ci.codelocs))
     stmtinfo = sv.stmt_info
+    ssavaluetypes = ci.ssavaluetypes::Vector{Any}
     while idx <= length(code)
         codeloc = ci.codelocs[idx]
         if coverage && codeloc != prevloc && codeloc != 0
             # insert a side-effect instruction before the current instruction in the same basic block
             insert!(code, idx, Expr(:code_coverage_effect))
             insert!(ci.codelocs, idx, codeloc)
-            insert!(ci.ssavaluetypes, idx, Nothing)
+            insert!(ssavaluetypes, idx, Nothing)
             insert!(stmtinfo, idx, nothing)
             changemap[oldidx] += 1
             if oldidx < length(labelmap)
@@ -58,12 +59,12 @@ function convert_to_ircode(ci::CodeInfo, code::Vector{Any}, coverage::Bool, narg
             idx += 1
             prevloc = codeloc
         end
-        if code[idx] isa Expr && ci.ssavaluetypes[idx] === Union{}
+        if code[idx] isa Expr && ssavaluetypes[idx] === Union{}
             if !(idx < length(code) && isa(code[idx + 1], ReturnNode) && !isdefined((code[idx + 1]::ReturnNode), :val))
                 # insert unreachable in the same basic block after the current instruction (splitting it)
                 insert!(code, idx + 1, ReturnNode())
                 insert!(ci.codelocs, idx + 1, ci.codelocs[idx])
-                insert!(ci.ssavaluetypes, idx + 1, Union{})
+                insert!(ssavaluetypes, idx + 1, Union{})
                 insert!(stmtinfo, idx + 1, nothing)
                 if oldidx < length(changemap)
                     changemap[oldidx + 1] += 1

base/compiler/ssair/inlining.jl

@@ -630,7 +630,7 @@ function rewrite_apply_exprargs!(ir::IRCode, todo::Vector{Pair{Int, Any}}, idx::
                 call = thisarginfo.each[i]
                 new_stmt = Expr(:call, argexprs[2], def, state...)
                 state1 = insert_node!(ir, idx, call.rt, new_stmt)
-                new_sig = with_atype(call_sig(ir, new_stmt))
+                new_sig = with_atype(call_sig(ir, new_stmt)::Signature)
                 if isa(call.info, MethodMatchInfo) || isa(call.info, UnionSplitInfo)
                     info = isa(call.info, MethodMatchInfo) ?
                         MethodMatchInfo[call.info] : call.info.matches
@@ -680,7 +680,7 @@ function resolve_todo(todo::InliningTodo, et::Union{EdgeTracker, Nothing}, cache
     spec = todo.spec::DelayedInliningSpec
     isconst, src = find_inferred(todo.mi, spec.atypes, caches, spec.stmttype)
 
-    if isconst
+    if isconst && et !== nothing
         push!(et, todo.mi)
         return ConstantCase(src)
     end
@@ -988,9 +988,12 @@ function inline_invoke!(ir::IRCode, idx::Int, sig::Signature, invoke_data::Invok
             sig.atype, method.sig)::SimpleVector
     methsp = methsp::SimpleVector
     match = MethodMatch(metharg, methsp, method, true)
-    result = analyze_method!(match, sig.atypes, state.et, state.caches, state.params, calltype)
+    et = state.et
+    result = analyze_method!(match, sig.atypes, et, state.caches, state.params, calltype)
     handle_single_case!(ir, stmt, idx, result, true, todo)
-    intersect!(state.et, WorldRange(invoke_data.min_valid, invoke_data.max_valid))
+    if et !== nothing
+        intersect!(et, WorldRange(invoke_data.min_valid, invoke_data.max_valid))
+    end
     return nothing
 end
 
@@ -1118,6 +1121,7 @@ function analyze_single_call!(ir::IRCode, todo::Vector{Pair{Int, Any}}, idx::Int
                 sig.atype, only_method.sig)::SimpleVector
             match = MethodMatch(metharg, methsp, only_method, true)
         else
+            meth = meth::MethodLookupResult
             @assert length(meth) == 1
             match = meth[1]
         end
@@ -1145,6 +1149,8 @@ end
 function assemble_inline_todo!(ir::IRCode, state::InliningState)
     # todo = (inline_idx, (isva, isinvoke, na), method, spvals, inline_linetable, inline_ir, lie)
     todo = Pair{Int, Any}[]
+    et = state.et
+    method_table = state.method_table
     for idx in 1:length(ir.stmts)
         r = process_simple!(ir, todo, idx, state)
         r === nothing && continue
@@ -1176,20 +1182,18 @@ function assemble_inline_todo!(ir::IRCode, state::InliningState)
         nu = unionsplitcost(sig.atypes)
         if nu == 1 || nu > state.params.MAX_UNION_SPLITTING
             if !isa(info, MethodMatchInfo)
-                if state.method_table === nothing
-                    continue
-                end
-                info = recompute_method_matches(sig.atype, state.params, state.et, state.method_table)
+                method_table === nothing && continue
+                et === nothing && continue
+                info = recompute_method_matches(sig.atype, state.params, et, method_table)
             end
             infos = MethodMatchInfo[info]
         else
             if !isa(info, UnionSplitInfo)
-                if state.method_table === nothing
-                    continue
-                end
+                method_table === nothing && continue
+                et === nothing && continue
                 infos = MethodMatchInfo[]
                 for union_sig in UnionSplitSignature(sig.atypes)
-                    push!(infos, recompute_method_matches(argtypes_to_type(union_sig), state.params, state.et, state.method_table))
+                    push!(infos, recompute_method_matches(argtypes_to_type(union_sig), state.params, et, method_table))
                 end
             else
                 infos = info.matches

base/compiler/ssair/ir.jl

@@ -139,13 +139,15 @@ function compute_basic_blocks(stmts::Vector{Any})
     return CFG(blocks, basic_block_index)
 end
 
+# this function assumes insert position exists
 function first_insert_for_bb(code, cfg::CFG, block::Int)
     for idx in cfg.blocks[block].stmts
         stmt = code[idx]
         if !isa(stmt, PhiNode)
             return idx
         end
     end
+    error("any insert position isn't found")
 end
 
 # SSA-indexed nodes
@@ -893,7 +895,7 @@ function kill_edge!(compact::IncrementalCompact, active_bb::Int, from::Int, to::
     # Check if the block is now dead
     if length(preds) == 0
         for succ in copy(compact.result_bbs[compact.bb_rename_succ[to]].succs)
-            kill_edge!(compact, active_bb, to, findfirst(x->x === succ, compact.bb_rename_pred))
+            kill_edge!(compact, active_bb, to, findfirst(x->x === succ, compact.bb_rename_pred)::Int)
         end
         if to < active_bb
             # Kill all statements in the block

base/compiler/ssair/slot2ssa.jl

@@ -764,7 +764,7 @@ function construct_ssa!(ci::CodeInfo, ir::IRCode, domtree::DomTree, defuse, narg
                     # Having undef_token appear on the RHS is possible if we're on a dead branch.
                     # Do something reasonable here, by marking the LHS as undef as well.
                     if val !== undef_token
-                        incoming_vals[id] = SSAValue(make_ssa!(ci, code, idx, id, typ))
+                        incoming_vals[id] = SSAValue(make_ssa!(ci, code, idx, id, typ)::Int)
                     else
                         code[idx] = nothing
                         incoming_vals[id] = undef_token

base/compiler/ssair/verify.jl

@@ -14,13 +14,13 @@ end
 function check_op(ir::IRCode, domtree::DomTree, @nospecialize(op), use_bb::Int, use_idx::Int, print::Bool)
     if isa(op, SSAValue)
         if op.id > length(ir.stmts)
-            def_bb = block_for_inst(ir.cfg, ir.new_nodes[op.id - length(ir.stmts)].pos)
+            def_bb = block_for_inst(ir.cfg, ir.new_nodes.info[op.id - length(ir.stmts)].pos)
         else
             def_bb = block_for_inst(ir.cfg, op.id)
         end
         if (def_bb == use_bb)
             if op.id > length(ir.stmts)
-                @assert ir.new_nodes[op.id - length(ir.stmts)].pos <= use_idx
+                @assert ir.new_nodes.info[op.id - length(ir.stmts)].pos <= use_idx
             else
                 if op.id >= use_idx
                     @verify_error "Def ($(op.id)) does not dominate use ($(use_idx)) in same BB"

base/compiler/typeinfer.jl

@@ -715,8 +715,8 @@ function merge_call_chain!(parent::InferenceState, ancestor::InferenceState, chi
         add_cycle_backedge!(child, parent, parent.currpc)
         union_caller_cycle!(ancestor, child)
         child = parent
-        parent = child.parent
         child === ancestor && break
+        parent = child.parent::InferenceState
     end
 end
 

base/compiler/typelattice.jl

@@ -317,7 +317,7 @@ function stupdate!(state::VarTable, changes::StateUpdate)
     if !isa(changes.var, Slot)
         return stupdate!(state, changes.state)
     end
-    newstate = false
+    newstate = nothing
     changeid = slot_id(changes.var::Slot)
     for i = 1:length(state)
         if i == changeid
@@ -346,7 +346,7 @@ function stupdate!(state::VarTable, changes::StateUpdate)
 end
 
 function stupdate!(state::VarTable, changes::VarTable)
-    newstate = false
+    newstate = nothing
     for i = 1:length(state)
         newtype = changes[i]
         oldtype = state[i]
@@ -360,7 +360,7 @@ end
 
 stupdate!(state::Nothing, changes::VarTable) = copy(changes)
 
-stupdate!(state::Nothing, changes::Nothing) = false
+stupdate!(state::Nothing, changes::Nothing) = nothing
 
 function stupdate1!(state::VarTable, change::StateUpdate)
     if !isa(change.var, Slot)

base/compiler/typeutils.jl

@@ -204,18 +204,18 @@ end
 # unioncomplexity estimates the number of calls to `tmerge` to obtain the given type by
 # counting the Union instances, taking also into account those hidden in a Tuple or UnionAll
 function unioncomplexity(u::Union)
-    return unioncomplexity(u.a) + unioncomplexity(u.b) + 1
+    return unioncomplexity(u.a)::Int + unioncomplexity(u.b)::Int + 1
 end
 function unioncomplexity(t::DataType)
     t.name === Tuple.name || isvarargtype(t) || return 0
     c = 0
     for ti in t.parameters
-        c = max(c, unioncomplexity(ti))
+        c = max(c, unioncomplexity(ti)::Int)
     end
     return c
 end
-unioncomplexity(u::UnionAll) = max(unioncomplexity(u.body), unioncomplexity(u.var.ub))
-unioncomplexity(t::Core.TypeofVararg) = isdefined(t, :T) ? unioncomplexity(t.T) : 0
+unioncomplexity(u::UnionAll) = max(unioncomplexity(u.body)::Int, unioncomplexity(u.var.ub)::Int)
+unioncomplexity(t::Core.TypeofVararg) = isdefined(t, :T) ? unioncomplexity(t.T)::Int : 0
 unioncomplexity(@nospecialize(x)) = 0
 
 function improvable_via_constant_propagation(@nospecialize(t))

base/compiler/validation.jl

@@ -1,7 +1,7 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
 # Expr head => argument count bounds
-const VALID_EXPR_HEADS = IdDict{Any,Any}(
+const VALID_EXPR_HEADS = IdDict{Symbol,UnitRange}(
     :call => 1:typemax(Int),
     :invoke => 2:typemax(Int),
     :static_parameter => 1:1,

base/essentials.jl

@@ -257,10 +257,14 @@ end
 
 function rewrap_unionall(t::Core.TypeofVararg, @nospecialize(u))
     isdefined(t, :T) || return t
+    if !isa(u, UnionAll)
+        return t
+    end
+    T = rewrap_unionall(t.T, u)
     if !isdefined(t, :N) || t.N === u.var
-        return Vararg{rewrap_unionall(t.T, u)}
+        return Vararg{T}
     end
-    Vararg{rewrap_unionall(t.T, u), t.N}
+    return Vararg{T, t.N}
 end
 
 # replace TypeVars in all enclosing UnionAlls with fresh TypeVars