effects: taint overlay-ed method's :nonoverlayed effect bit

Previously we tainted `:nonoverlayed` bit of the callers of overlay-ed
methods by looking at the method match results, rather than tainting
the overlay-ed methods' effects themselves. This is a bit confusing
since it is not aligned with how the other effect bits are tainted.

Moreover, I am planning to allow `Base.@assume_effects`-override for
`:nonoverlayed` effect bit in the future to solve issues like
JuliaGPU/GPUCompiler.jl#384, and it would be necessary for the solution
to be functional that `:nonoverlayed` effect bit is tainted on the
callee-side as the other effect bits are.

This commit refactors the compiler internal so that we taint
`:nonoverlayed` bit of overlay-ed methods and propagate it to callers.
It turns out that this refactor simplifies the internal implementations
a lot.

base/compiler/abstractinterpretation.jl

@@ -16,7 +16,7 @@ function abstract_call_gf_by_type(interp::AbstractInterpreter, @nospecialize(f),
         # At this point we are guaranteed to end up throwing on this path,
         # which is all that's required for :consistent-cy. Of course, we don't
         # know anything else about this statement.
-        effects = Effects(; consistent=ALWAYS_TRUE, nonoverlayed=!isoverlayed(method_table(interp)))
+        effects = Effects(; consistent=ALWAYS_TRUE)
         return CallMeta(Any, effects, NoCallInfo())
     end
 
@@ -28,7 +28,7 @@ function abstract_call_gf_by_type(interp::AbstractInterpreter, @nospecialize(f),
         return CallMeta(Any, Effects(), NoCallInfo())
     end
 
-    (; valid_worlds, applicable, info, nonoverlayed) = matches
+    (; valid_worlds, applicable, info) = matches
     update_valid_age!(sv, valid_worlds)
     napplicable = length(applicable)
     rettype = Bottom
@@ -39,7 +39,7 @@ function abstract_call_gf_by_type(interp::AbstractInterpreter, @nospecialize(f),
     const_results = Union{Nothing,ConstResult}[]
     multiple_matches = napplicable > 1
     fargs = arginfo.fargs
-    all_effects = Effects(EFFECTS_TOTAL; nonoverlayed)
+    all_effects = EFFECTS_TOTAL
 
     𝕃ₚ = ipo_lattice(interp)
     for i in 1:napplicable
@@ -205,7 +205,6 @@ struct MethodMatches
     valid_worlds::WorldRange
     mt::MethodTable
     fullmatch::Bool
-    nonoverlayed::Bool
 end
 any_ambig(info::MethodMatchInfo) = info.results.ambig
 any_ambig(m::MethodMatches) = any_ambig(m.info)
@@ -217,7 +216,6 @@ struct UnionSplitMethodMatches
     valid_worlds::WorldRange
     mts::Vector{MethodTable}
     fullmatches::Vector{Bool}
-    nonoverlayed::Bool
 end
 any_ambig(m::UnionSplitMethodMatches) = any(any_ambig, m.info.matches)
 
@@ -233,19 +231,16 @@ function find_matching_methods(𝕃::AbstractLattice,
         valid_worlds = WorldRange()
         mts = MethodTable[]
         fullmatches = Bool[]
-        nonoverlayed = true
         for i in 1:length(split_argtypes)
             arg_n = split_argtypes[i]::Vector{Any}
             sig_n = argtypes_to_type(arg_n)
             mt = ccall(:jl_method_table_for, Any, (Any,), sig_n)
             mt === nothing && return FailedMethodMatch("Could not identify method table for call")
             mt = mt::MethodTable
-            result = findall(sig_n, method_table; limit = max_methods)
-            if result === nothing
+            matches = findall(sig_n, method_table; limit = max_methods)
+            if matches === nothing
                 return FailedMethodMatch("For one of the union split cases, too many methods matched")
             end
-            (; matches, overlayed) = result
-            nonoverlayed &= !overlayed
             push!(infos, MethodMatchInfo(matches))
             for m in matches
                 push!(applicable, m)
@@ -271,28 +266,25 @@ function find_matching_methods(𝕃::AbstractLattice,
                                        UnionSplitInfo(infos),
                                        valid_worlds,
                                        mts,
-                                       fullmatches,
-                                       nonoverlayed)
+                                       fullmatches)
     else
         mt = ccall(:jl_method_table_for, Any, (Any,), atype)
         if mt === nothing
             return FailedMethodMatch("Could not identify method table for call")
         end
         mt = mt::MethodTable
-        result = findall(atype, method_table; limit = max_methods)
-        if result === nothing
+        matches = findall(atype, method_table; limit = max_methods)
+        if matches === nothing
             # this means too many methods matched
             # (assume this will always be true, so we don't compute / update valid age in this case)
             return FailedMethodMatch("Too many methods matched")
         end
-        (; matches, overlayed) = result
         fullmatch = any(match::MethodMatch->match.fully_covers, matches)
         return MethodMatches(matches.matches,
                              MethodMatchInfo(matches),
                              matches.valid_worlds,
                              mt,
-                             fullmatch,
-                             !overlayed)
+                             fullmatch)
     end
 end
 
@@ -862,7 +854,7 @@ function concrete_eval_eligible(interp::AbstractInterpreter,
     mi = result.edge
     if mi !== nothing && is_foldable(effects)
         if f !== nothing && is_all_const_arg(arginfo, #=start=#2)
-            if is_nonoverlayed(mi.def::Method) && (!isoverlayed(method_table(interp)) || is_nonoverlayed(effects))
+            if is_nonoverlayed(interp) || is_nonoverlayed(effects)
                 return :concrete_eval
             end
             # disable concrete-evaluation if this function call is tainted by some overlayed
@@ -1924,7 +1916,7 @@ function abstract_invoke(interp::AbstractInterpreter, (; fargs, argtypes)::ArgIn
     lookupsig = rewrap_unionall(Tuple{ft, unwrapped.parameters...}, types)::Type
     nargtype = Tuple{ft, nargtype.parameters...}
     argtype = Tuple{ft, argtype.parameters...}
-    match, valid_worlds, overlayed = findsup(lookupsig, method_table(interp))
+    match, valid_worlds = findsup(lookupsig, method_table(interp))
     match === nothing && return CallMeta(Any, Effects(), NoCallInfo())
     update_valid_age!(sv, valid_worlds)
     method = match.method
@@ -1955,7 +1947,6 @@ function abstract_invoke(interp::AbstractInterpreter, (; fargs, argtypes)::ArgIn
         end
     end
     rt = from_interprocedural!(interp, rt, sv, arginfo, sig)
-    effects = Effects(effects; nonoverlayed = !overlayed)
     info = InvokeCallInfo(match, const_result)
     edge !== nothing && add_invoke_backedge!(sv, lookupsig, edge)
     return CallMeta(rt, effects, info)

base/compiler/inferencestate.jl

@@ -296,7 +296,11 @@ mutable struct InferenceState
             ipo_effects = Effects(ipo_effects; effect_free = ALWAYS_FALSE)
         end
 
-        restrict_abstract_call_sites = isa(linfo.def, Module)
+        if def isa Method
+            ipo_effects = Effects(ipo_effects; nonoverlayed=is_nonoverlayed(def))
+        end
+
+        restrict_abstract_call_sites = isa(def, Module)
         @assert cache === :no || cache === :local || cache === :global
         cached = cache === :global
 
@@ -314,6 +318,13 @@ mutable struct InferenceState
     end
 end
 
+is_nonoverlayed(m::Method) = !isdefined(m, :external_mt)
+is_nonoverlayed(interp::AbstractInterpreter) = !isoverlayed(method_table(interp))
+isoverlayed(::MethodTableView) = error("unsatisfied MethodTableView interface")
+isoverlayed(::InternalMethodTable) = false
+isoverlayed(::OverlayMethodTable) = true
+isoverlayed(mt::CachedMethodTable) = isoverlayed(mt.table)
+
 is_inferred(sv::InferenceState) = is_inferred(sv.result)
 is_inferred(result::InferenceResult) = result.result !== nothing
 

base/compiler/methodtable.jl

@@ -16,11 +16,6 @@ function iterate(result::MethodLookupResult, args...)
 end
 getindex(result::MethodLookupResult, idx::Int) = getindex(result.matches, idx)::MethodMatch
 
-struct MethodMatchResult
-    matches::MethodLookupResult
-    overlayed::Bool
-end
-
 """
     struct InternalMethodTable <: MethodTableView
 
@@ -55,47 +50,42 @@ Overlays another method table view with an additional local fast path cache that
 can respond to repeated, identical queries faster than the original method table.
 """
 struct CachedMethodTable{T<:MethodTableView} <: MethodTableView
-    cache::IdDict{MethodMatchKey, Union{Nothing,MethodMatchResult}}
+    cache::IdDict{MethodMatchKey, Union{Nothing,MethodLookupResult}}
     table::T
 end
-CachedMethodTable(table::T) where T = CachedMethodTable{T}(IdDict{MethodMatchKey, Union{Nothing,MethodMatchResult}}(), table)
+CachedMethodTable(table::T) where T = CachedMethodTable{T}(IdDict{MethodMatchKey, Union{Nothing,MethodLookupResult}}(), table)
 
 """
     findall(sig::Type, view::MethodTableView; limit::Int=-1) ->
-        MethodMatchResult(matches::MethodLookupResult, overlayed::Bool) or nothing
+        matches::MethodLookupResult or nothing
 
 Find all methods in the given method table `view` that are applicable to the given signature `sig`.
 If no applicable methods are found, an empty result is returned.
 If the number of applicable methods exceeded the specified `limit`, `nothing` is returned.
 Note that the default setting `limit=-1` does not limit the number of applicable methods.
 `overlayed` indicates if any of the matching methods comes from an overlayed method table.
 """
-function findall(@nospecialize(sig::Type), table::InternalMethodTable; limit::Int=-1)
-    result = _findall(sig, nothing, table.world, limit)
-    result === nothing && return nothing
-    return MethodMatchResult(result, false)
-end
+findall(@nospecialize(sig::Type), table::InternalMethodTable; limit::Int=-1) =
+    _findall(sig, nothing, table.world, limit)
 
 function findall(@nospecialize(sig::Type), table::OverlayMethodTable; limit::Int=-1)
     result = _findall(sig, table.mt, table.world, limit)
     result === nothing && return nothing
     nr = length(result)
     if nr ≥ 1 && result[nr].fully_covers
         # no need to fall back to the internal method table
-        return MethodMatchResult(result, true)
+        return result
     end
     # fall back to the internal method table
     fallback_result = _findall(sig, nothing, table.world, limit)
     fallback_result === nothing && return nothing
     # merge the fallback match results with the internal method table
-    return MethodMatchResult(
-        MethodLookupResult(
-            vcat(result.matches, fallback_result.matches),
-            WorldRange(
-                max(result.valid_worlds.min_world, fallback_result.valid_worlds.min_world),
-                min(result.valid_worlds.max_world, fallback_result.valid_worlds.max_world)),
-            result.ambig | fallback_result.ambig),
-        !isempty(result))
+    return MethodLookupResult(
+        vcat(result.matches, fallback_result.matches),
+        WorldRange(
+            max(result.valid_worlds.min_world, fallback_result.valid_worlds.min_world),
+            min(result.valid_worlds.max_world, fallback_result.valid_worlds.max_world)),
+        result.ambig | fallback_result.ambig)
 end
 
 function _findall(@nospecialize(sig::Type), mt::Union{Nothing,MethodTable}, world::UInt, limit::Int)
@@ -138,21 +128,19 @@ In both cases `nothing` is returned.
 
 `overlayed` indicates if any of the matching methods comes from an overlayed method table.
 """
-function findsup(@nospecialize(sig::Type), table::InternalMethodTable)
-    return (_findsup(sig, nothing, table.world)..., false)
-end
+findsup(@nospecialize(sig::Type), table::InternalMethodTable) =
+    _findsup(sig, nothing, table.world)
 
 function findsup(@nospecialize(sig::Type), table::OverlayMethodTable)
     match, valid_worlds = _findsup(sig, table.mt, table.world)
-    match !== nothing && return match, valid_worlds, true
+    match !== nothing && return match, valid_worlds
     # fall back to the internal method table
     fallback_match, fallback_valid_worlds = _findsup(sig, nothing, table.world)
     return (
         fallback_match,
         WorldRange(
             max(valid_worlds.min_world, fallback_valid_worlds.min_world),
-            min(valid_worlds.max_world, fallback_valid_worlds.max_world)),
-        false)
+            min(valid_worlds.max_world, fallback_valid_worlds.max_world)))
 end
 
 function _findsup(@nospecialize(sig::Type), mt::Union{Nothing,MethodTable}, world::UInt)
@@ -166,10 +154,3 @@ end
 
 # This query is not cached
 findsup(@nospecialize(sig::Type), table::CachedMethodTable) = findsup(sig, table.table)
-
-isoverlayed(::MethodTableView) = error("unsatisfied MethodTableView interface")
-isoverlayed(::InternalMethodTable) = false
-isoverlayed(::OverlayMethodTable) = true
-isoverlayed(mt::CachedMethodTable) = isoverlayed(mt.table)
-isoverlayed(m::Method) = isdefined(m, :external_mt)
-is_nonoverlayed(m::Method) = !isoverlayed(m)

base/compiler/ssair/irinterp.jl

@@ -15,7 +15,7 @@ function concrete_eval_invoke(interp::AbstractInterpreter,
     argtypes === nothing && return Pair{Any,Bool}(Bottom, false)
     effects = decode_effects(code.ipo_purity_bits)
     if (is_foldable(effects) && is_all_const_arg(argtypes, #=start=#1) &&
-        is_nonoverlayed(effects) && is_nonoverlayed(mi.def::Method))
+        (is_nonoverlayed(interp) || is_nonoverlayed(effects)))
         args = collect_const_args(argtypes, #=start=#1)
         value = let world = get_world_counter(interp)
             try

base/compiler/tfuncs.jl

@@ -2763,7 +2763,7 @@ function _hasmethod_tfunc(interp::AbstractInterpreter, argtypes::Vector{Any}, sv
     if !isa(mt, MethodTable)
         return CallMeta(Bool, EFFECTS_THROWS, NoCallInfo())
     end
-    match, valid_worlds, overlayed = findsup(types, method_table(interp))
+    match, valid_worlds = findsup(types, method_table(interp))
     update_valid_age!(sv, valid_worlds)
     if match === nothing
         rt = Const(false)

base/reflection.jl

@@ -1633,12 +1633,11 @@ function infer_effects(@nospecialize(f), @nospecialize(types=default_tt(f));
             Core.Compiler.ArgInfo(nothing, argtypes), rt)
     end
     tt = signature_type(f, types)
-    result = Core.Compiler.findall(tt, Core.Compiler.method_table(interp))
-    if result === missing
+    matches = Core.Compiler.findall(tt, Core.Compiler.method_table(interp))
+    if matches === missing
         # unanalyzable call, return the unknown effects
         return Core.Compiler.Effects()
     end
-    (; matches) = result
     effects = Core.Compiler.EFFECTS_TOTAL
     if matches.ambig || !any(match::Core.MethodMatch->match.fully_covers, matches.matches)
         # account for the fact that we may encounter a MethodError with a non-covered or ambiguous signature.

test/compiler/AbstractInterpreter.jl

@@ -55,7 +55,8 @@ callstrange(::Float64) = strangesin(x)
 callstrange(::Nothing) = Core.compilerbarrier(:type, nothing) # trigger inference bail out
 callstrange_entry(x) = callstrange(x) # needs to be defined here because of world age
 let interp = MTOverlayInterp(Set{Any}())
-    matches = Core.Compiler.findall(Tuple{typeof(callstrange),Any}, Core.Compiler.method_table(interp)).matches
+    matches = Core.Compiler.findall(Tuple{typeof(callstrange),Any}, Core.Compiler.method_table(interp))
+    @test matches !== nothing
     @test Core.Compiler.length(matches) == 2
     if Core.Compiler.getindex(matches, 1).method == which(callstrange, (Nothing,))
         @test Base.infer_effects(callstrange_entry, (Any,); interp) |> !Core.Compiler.is_nonoverlayed

test/compiler/datastructures.jl

@@ -8,7 +8,7 @@ using Test
     sig = Tuple{typeof(*), Any, Any}
     result1 = Core.Compiler.findall(sig, table; limit=-1)
     result2 = Core.Compiler.findall(sig, table; limit=Core.Compiler.InferenceParams().max_methods)
-    @test result1 !== nothing && !Core.Compiler.isempty(result1.matches)
+    @test result1 !== nothing && !Core.Compiler.isempty(result1)
     @test result2 === nothing
 end