inference: enable constant propagation for invoked calls, fixes #41024

 (#41383)

* inference: enable constant propagation for `invoke`d calls, fixes #41024

Especially useful for defining mixins with typed interface fields, e.g.
```julia
abstract type AbstractInterface end # mixin, which expects common field `x::Int`
function Base.getproperty(x::AbstractInterface, sym::Symbol)
    if sym === :x
        return getfield(x, sym)::Int # inferred field
    else
        return getfield(x, sym)      # fallback
    end
end

abstract type AbstractInterfaceExtended <: AbstractInterface end # extended mixin, which expects additional common field `y::Rational{Int}`
function Base.getproperty(x::AbstractInterfaceExtended, sym::Symbol)
    if sym === :y
        return getfield(x, sym)::Rational{Int}
    end
    return Base.@invoke getproperty(x::AbstractInterface, sym::Symbol)
end
```

As a bonus, inliner is able to use `InferenceResult` as a fast inlining
pass for constant-prop'ed `invoke`s

* improve compile-time latency

* Update base/compiler/abstractinterpretation.jl

* Update base/compiler/abstractinterpretation.jl

base/compiler/abstractinterpretation.jl

@@ -1135,7 +1135,8 @@ function abstract_call_unionall(argtypes::Vector{Any})
 end
 
 function abstract_invoke(interp::AbstractInterpreter, argtypes::Vector{Any}, sv::InferenceState)
-    ft = widenconst(argtype_by_index(argtypes, 2))
+    ft′ = argtype_by_index(argtypes, 2)
+    ft = widenconst(ft′)
     ft === Bottom && return CallMeta(Bottom, false)
     (types, isexact, isconcrete, istype) = instanceof_tfunc(argtype_by_index(argtypes, 3))
     types === Bottom && return CallMeta(Bottom, false)
@@ -1149,15 +1150,30 @@ function abstract_invoke(interp::AbstractInterpreter, argtypes::Vector{Any}, sv:
     nargtype = Tuple{ft, nargtype.parameters...}
     argtype = Tuple{ft, argtype.parameters...}
     result = findsup(types, method_table(interp))
-    if result === nothing
-        return CallMeta(Any, false)
-    end
+    result === nothing && return CallMeta(Any, false)
     method, valid_worlds = result
     update_valid_age!(sv, valid_worlds)
     (ti, env::SimpleVector) = ccall(:jl_type_intersection_with_env, Any, (Any, Any), nargtype, method.sig)::SimpleVector
-    rt, edge = typeinf_edge(interp, method, ti, env, sv)
+    (; rt, edge) = result = abstract_call_method(interp, method, ti, env, false, sv)
     edge !== nothing && add_backedge!(edge::MethodInstance, sv)
-    return CallMeta(rt, InvokeCallInfo(MethodMatch(ti, env, method, argtype <: method.sig)))
+    match = MethodMatch(ti, env, method, argtype <: method.sig)
+    # try constant propagation with manual inlinings of some of the heuristics
+    # since some checks within `abstract_call_method_with_const_args` seem a bit costly
+    const_prop_entry_heuristic(interp, result, sv) || return CallMeta(rt, InvokeCallInfo(match, nothing))
+    argtypes′ = argtypes[4:end]
+    const_prop_argument_heuristic(interp, argtypes′) || const_prop_rettype_heuristic(interp, rt) || return CallMeta(rt, InvokeCallInfo(match, nothing))
+    pushfirst!(argtypes′, ft)
+    # # typeintersect might have narrowed signature, but the accuracy gain doesn't seem worth the cost involved with the lattice comparisons
+    # for i in 1:length(argtypes′)
+    #     t, a = ti.parameters[i], argtypes′[i]
+    #     argtypes′[i] = t ⊑ a ? t : a
+    # end
+    const_rt, const_result = abstract_call_method_with_const_args(interp, result, argtype_to_function(ft′), argtypes′, match, sv, false)
+    if const_rt !== rt && const_rt ⊑ rt
+        return CallMeta(const_rt, InvokeCallInfo(match, const_result))
+    else
+        return CallMeta(rt, InvokeCallInfo(match, nothing))
+    end
 end
 
 # call where the function is known exactly
@@ -1291,17 +1307,12 @@ function abstract_call(interp::AbstractInterpreter, fargs::Union{Nothing,Vector{
                        sv::InferenceState, max_methods::Int = InferenceParams(interp).MAX_METHODS)
     #print("call ", e.args[1], argtypes, "\n\n")
     ft = argtypes[1]
-    if isa(ft, Const)
-        f = ft.val
-    elseif isconstType(ft)
-        f = ft.parameters[1]
-    elseif isa(ft, DataType) && isdefined(ft, :instance)
-        f = ft.instance
-    elseif isa(ft, PartialOpaque)
+    f = argtype_to_function(ft)
+    if isa(ft, PartialOpaque)
         return abstract_call_opaque_closure(interp, ft, argtypes[2:end], sv)
     elseif isa(unwrap_unionall(ft), DataType) && unwrap_unionall(ft).name === typename(Core.OpaqueClosure)
         return CallMeta(rewrap_unionall(unwrap_unionall(ft).parameters[2], ft), false)
-    else
+    elseif f === nothing
         # non-constant function, but the number of arguments is known
         # and the ft is not a Builtin or IntrinsicFunction
         if typeintersect(widenconst(ft), Union{Builtin, Core.OpaqueClosure}) != Union{}
@@ -1313,6 +1324,18 @@ function abstract_call(interp::AbstractInterpreter, fargs::Union{Nothing,Vector{
     return abstract_call_known(interp, f, fargs, argtypes, sv, max_methods)
 end
 
+function argtype_to_function(@nospecialize(ft))
+    if isa(ft, Const)
+        return ft.val
+    elseif isconstType(ft)
+        return ft.parameters[1]
+    elseif isa(ft, DataType) && isdefined(ft, :instance)
+        return ft.instance
+    else
+        return nothing
+    end
+end
+
 function sp_type_rewrap(@nospecialize(T), linfo::MethodInstance, isreturn::Bool)
     isref = false
     if T === Bottom

base/compiler/ssair/inlining.jl

@@ -1049,12 +1049,12 @@ is_builtin(s::Signature) =
     isa(s.f, Builtin) ||
     s.ft ⊑ Builtin
 
-function inline_invoke!(ir::IRCode, idx::Int, sig::Signature, info::InvokeCallInfo,
+function inline_invoke!(ir::IRCode, idx::Int, sig::Signature, (; match, result)::InvokeCallInfo,
         state::InliningState, todo::Vector{Pair{Int, Any}})
     stmt = ir.stmts[idx][:inst]
     calltype = ir.stmts[idx][:type]
 
-    if !info.match.fully_covers
+    if !match.fully_covers
         # TODO: We could union split out the signature check and continue on
         return nothing
     end
@@ -1064,7 +1064,17 @@ function inline_invoke!(ir::IRCode, idx::Int, sig::Signature, info::InvokeCallIn
     atypes = atypes[4:end]
     pushfirst!(atypes, atype0)
 
-    result = analyze_method!(info.match, atypes, state, calltype)
+    if isa(result, InferenceResult)
+        item = InliningTodo(result, atypes, calltype)
+        validate_sparams(item.mi.sparam_vals) || return nothing
+        if argtypes_to_type(atypes) <: item.mi.def.sig
+            state.mi_cache !== nothing && (item = resolve_todo(item, state))
+            handle_single_case!(ir, stmt, idx, item, true, todo)
+            return nothing
+        end
+    end
+
+    result = analyze_method!(match, atypes, state, calltype)
     handle_single_case!(ir, stmt, idx, result, true, todo)
     return nothing
 end

base/compiler/stmtinfo.jl

@@ -108,6 +108,7 @@ method being processed.
 """
 struct InvokeCallInfo
     match::MethodMatch
+    result::Union{Nothing,InferenceResult}
 end
 
 struct OpaqueClosureCallInfo

test/compiler/inference.jl

@@ -3355,3 +3355,43 @@ let
         Expr(:opaque_closure_method, nothing, 2, LineNumberNode(0, nothing), ci)))(true, 1.0)
     @test Base.return_types(oc, Tuple{}) == Any[Float64]
 end
+
+@testset "constant prop' on `invoke` calls" begin
+    m = Module()
+
+    # simple cases
+    @eval m begin
+        f(a::Any,    sym::Bool) = sym ? Any : :any
+        f(a::Number, sym::Bool) = sym ? Number : :number
+    end
+    @test (@eval m Base.return_types((Any,)) do a
+        Base.@invoke f(a::Any, true::Bool)
+    end) == Any[Type{Any}]
+    @test (@eval m Base.return_types((Any,)) do a
+        Base.@invoke f(a::Number, true::Bool)
+    end) == Any[Type{Number}]
+    @test (@eval m Base.return_types((Any,)) do a
+        Base.@invoke f(a::Any, false::Bool)
+    end) == Any[Symbol]
+    @test (@eval m Base.return_types((Any,)) do a
+        Base.@invoke f(a::Number, false::Bool)
+    end) == Any[Symbol]
+
+    # https://github.com/JuliaLang/julia/issues/41024
+    @eval m begin
+        # mixin, which expects common field `x::Int`
+        abstract type AbstractInterface end
+        Base.getproperty(x::AbstractInterface, sym::Symbol) =
+            sym === :x ? getfield(x, sym)::Int :
+            return getfield(x, sym) # fallback
+
+        # extended mixin, which expects additional field `y::Rational{Int}`
+        abstract type AbstractInterfaceExtended <: AbstractInterface end
+        Base.getproperty(x::AbstractInterfaceExtended, sym::Symbol) =
+            sym === :y ? getfield(x, sym)::Rational{Int} :
+            return Base.@invoke getproperty(x::AbstractInterface, sym::Symbol)
+    end
+    @test (@eval m Base.return_types((AbstractInterfaceExtended,)) do x
+        x.x
+    end) == Any[Int]
+end