inference: add error/throwness checks for setfield! (JuliaLang#43603)

In a similar spirit to JuliaLang#43587, this commit introduces error check for
`setfield!`. We can bail out from inference if we can prove either of:
- the object is not mutable type
- the object is `Module` object
- the value being assigned is incompatible with the declared type of
  object field

This commit also adds the throwness check for `setfield!` (i.e. `setfield!_nothrow`).
This throwness check won't be used in the current native compilation
pipeline since `setfield!` call can't be eliminated even if we can prove
that it never throws. But this throwness check would be used by
EscapeAnalysis.jl integration and so I'd like to include it in Base.

base/compiler/tfuncs.jl

@@ -775,7 +775,8 @@ function getfield_tfunc(s00, name, order, boundscheck)
     end
     return getfield_tfunc(s00, name)
 end
-function getfield_tfunc(@nospecialize(s00), @nospecialize(name))
+getfield_tfunc(@nospecialize(s00), @nospecialize(name)) = _getfield_tfunc(s00, name, false)
+function _getfield_tfunc(@nospecialize(s00), @nospecialize(name), setfield::Bool)
     s = unwrap_unionall(s00)
     if isa(s, Union)
         return tmerge(getfield_tfunc(rewrap_unionall(s.a, s00), name),
@@ -791,6 +792,7 @@ function getfield_tfunc(@nospecialize(s00), @nospecialize(name))
         if isa(name, Const)
             nv = name.val
             if isa(sv, Module)
+                setfield && return Bottom
                 if isa(nv, Symbol)
                     return abstract_eval_global(sv, nv)
                 end
@@ -834,9 +836,8 @@ function getfield_tfunc(@nospecialize(s00), @nospecialize(name))
         return Bottom
     end
     if s <: Module
-        if !(Symbol <: widenconst(name))
-            return Bottom
-        end
+        setfield && return Bottom
+        hasintersect(widenconst(name), Symbol) || return Bottom
         return Any
     end
     if s.name === _NAMEDTUPLE_NAME && !isconcretetype(s)
@@ -857,9 +858,10 @@ function getfield_tfunc(@nospecialize(s00), @nospecialize(name))
         return getfield_tfunc(_ts, name)
     end
     ftypes = datatype_fieldtypes(s)
+    nf = length(ftypes)
     # If no value has this type, then this statement should be unreachable.
     # Bail quickly now.
-    if !has_concrete_subtype(s) || isempty(ftypes)
+    if !has_concrete_subtype(s) || nf == 0
         return Bottom
     end
     if isa(name, Conditional)
@@ -870,12 +872,14 @@ function getfield_tfunc(@nospecialize(s00), @nospecialize(name))
         if !(Int <: name || Symbol <: name)
             return Bottom
         end
-        if length(ftypes) == 1
+        if nf == 1
             return rewrap_unionall(unwrapva(ftypes[1]), s00)
         end
         # union together types of all fields
         t = Bottom
-        for _ft in ftypes
+        for i in 1:nf
+            _ft = ftypes[i]
+            setfield && isconst(s, i) && continue
             t = tmerge(t, rewrap_unionall(unwrapva(_ft), s00))
             t === Any && break
         end
@@ -888,12 +892,13 @@ function getfield_tfunc(@nospecialize(s00), @nospecialize(name))
     if !isa(fld, Int)
         return Bottom
     end
-    nf = length(ftypes)
     if s <: Tuple && fld >= nf && isvarargtype(ftypes[nf])
         return rewrap_unionall(unwrapva(ftypes[nf]), s00)
     end
     if fld < 1 || fld > nf
         return Bottom
+    elseif setfield && isconst(s, fld)
+        return Bottom
     end
     R = ftypes[fld]
     if isempty(s.parameters)
@@ -902,8 +907,66 @@ function getfield_tfunc(@nospecialize(s00), @nospecialize(name))
     return rewrap_unionall(R, s00)
 end
 
-setfield!_tfunc(o, f, v, order) = (@nospecialize; v)
-setfield!_tfunc(o, f, v) = (@nospecialize; v)
+function setfield!_tfunc(o, f, v, order)
+    @nospecialize
+    if !isvarargtype(order)
+        hasintersect(widenconst(order), Symbol) || return Bottom
+    end
+    return setfield!_tfunc(o, f, v)
+end
+function setfield!_tfunc(o, f, v)
+    @nospecialize
+    mutability_errorcheck(o) || return Bottom
+    ft = _getfield_tfunc(o, f, true)
+    ft === Bottom && return Bottom
+    hasintersect(widenconst(v), widenconst(ft)) || return Bottom
+    return v
+end
+function mutability_errorcheck(@nospecialize obj)
+    objt0 = widenconst(obj)
+    objt = unwrap_unionall(objt0)
+    if isa(objt, Union)
+        return mutability_errorcheck(rewrap_unionall(objt.a, objt0)) ||
+               mutability_errorcheck(rewrap_unionall(objt.b, objt0))
+    elseif isa(objt, DataType)
+        # Can't say anything about abstract types
+        isabstracttype(objt) && return true
+        return ismutabletype(objt)
+    end
+    return true
+end
+
+function setfield!_nothrow(argtypes::Vector{Any})
+    if length(argtypes) == 4
+        order = argtypes[4]
+        order === Const(:not_atomic) || return false # currently setfield!_nothrow is assuming not atomic
+    else
+        length(argtypes) == 3 || return false
+    end
+    return setfield!_nothrow(argtypes[1], argtypes[2], argtypes[3])
+end
+function setfield!_nothrow(s00, name, v)
+    @nospecialize
+    s0 = widenconst(s00)
+    s = unwrap_unionall(s0)
+    if isa(s, Union)
+        return setfield!_nothrow(rewrap_unionall(s.a, s00), name, v) &&
+               setfield!_nothrow(rewrap_unionall(s.b, s00), name, v)
+    elseif isa(s, DataType)
+        # Can't say anything about abstract types
+        isabstracttype(s) && return false
+        ismutabletype(s) || return false
+        s.name.atomicfields == C_NULL || return false # TODO: currently we're only testing for ordering == :not_atomic
+        isa(name, Const) || return false
+        field = try_compute_fieldidx(s, name.val)
+        field === nothing && return false
+        # `try_compute_fieldidx` already check for field index bound.
+        isconst(s, field) && return false
+        v_expected = fieldtype(s0, field)
+        return v ⊑ v_expected
+    end
+    return false
+end
 
 swapfield!_tfunc(o, f, v, order) = (@nospecialize; getfield_tfunc(o, f))
 swapfield!_tfunc(o, f, v) = (@nospecialize; getfield_tfunc(o, f))

test/compiler/inference.jl

@@ -1639,6 +1639,112 @@ end
 @test getfield_tfunc(ARef{Int},Const(:x),Symbol,Symbol) === Union{}
 @test getfield_tfunc(ARef{Int},Const(:x),Bool,Bool) === Union{}
 
+import Core.Compiler: setfield!_tfunc, setfield!_nothrow, Const
+mutable struct XY{X,Y}
+    x::X
+    y::Y
+end
+mutable struct ABCDconst
+    const a
+    const b::Int
+    c
+    const d::Union{Int,Nothing}
+end
+@test setfield!_tfunc(Base.RefValue{Int}, Const(:x), Int) === Int
+@test setfield!_tfunc(Base.RefValue{Int}, Const(:x), Int, Symbol) === Int
+@test setfield!_tfunc(Base.RefValue{Int}, Const(1), Int) === Int
+@test setfield!_tfunc(Base.RefValue{Int}, Const(1), Int, Symbol) === Int
+@test setfield!_tfunc(Base.RefValue{Int}, Int, Int) === Int
+@test setfield!_tfunc(Base.RefValue{Any}, Const(:x), Int) === Int
+@test setfield!_tfunc(Base.RefValue{Any}, Const(:x), Int, Symbol) === Int
+@test setfield!_tfunc(Base.RefValue{Any}, Const(1), Int) === Int
+@test setfield!_tfunc(Base.RefValue{Any}, Const(1), Int, Symbol) === Int
+@test setfield!_tfunc(Base.RefValue{Any}, Int, Int) === Int
+@test setfield!_tfunc(XY{Any,Any}, Const(1), Int) === Int
+@test setfield!_tfunc(XY{Any,Any}, Const(2), Float64) === Float64
+@test setfield!_tfunc(XY{Int,Float64}, Const(1), Int) === Int
+@test setfield!_tfunc(XY{Int,Float64}, Const(2), Float64) === Float64
+@test setfield!_tfunc(ABCDconst, Const(:c), Any) === Any
+@test setfield!_tfunc(ABCDconst, Const(3), Any) === Any
+@test setfield!_tfunc(ABCDconst, Symbol, Any) === Any
+@test setfield!_tfunc(ABCDconst, Int, Any) === Any
+@test setfield!_tfunc(Union{Base.RefValue{Any},Some{Any}}, Const(:x), Int) === Int
+@test setfield!_tfunc(Union{Base.RefValue,Some{Any}}, Const(:x), Int) === Int
+@test setfield!_tfunc(Union{Base.RefValue{Any},Some{Any}}, Const(1), Int) === Int
+@test setfield!_tfunc(Union{Base.RefValue,Some{Any}}, Const(1), Int) === Int
+@test setfield!_tfunc(Union{Base.RefValue{Any},Some{Any}}, Symbol, Int) === Int
+@test setfield!_tfunc(Union{Base.RefValue,Some{Any}}, Symbol, Int) === Int
+@test setfield!_tfunc(Union{Base.RefValue{Any},Some{Any}}, Int, Int) === Int
+@test setfield!_tfunc(Union{Base.RefValue,Some{Any}}, Int, Int) === Int
+@test setfield!_tfunc(Any, Symbol, Int) === Int
+@test setfield!_tfunc(Any, Int, Int) === Int
+@test setfield!_tfunc(Any, Any, Int) === Int
+@test setfield!_tfunc(Base.RefValue{Int}, Const(:x), Float64) === Union{}
+@test setfield!_tfunc(Base.RefValue{Int}, Const(:x), Float64, Symbol) === Union{}
+@test setfield!_tfunc(Base.RefValue{Int}, Const(1), Float64) === Union{}
+@test setfield!_tfunc(Base.RefValue{Int}, Const(1), Float64, Symbol) === Union{}
+@test setfield!_tfunc(Base.RefValue{Int}, Int, Float64) === Union{}
+@test setfield!_tfunc(Base.RefValue{Any}, Const(:y), Int) === Union{}
+@test setfield!_tfunc(Base.RefValue{Any}, Const(:y), Int, Bool) === Union{}
+@test setfield!_tfunc(Base.RefValue{Any}, Const(2), Int) === Union{}
+@test setfield!_tfunc(Base.RefValue{Any}, Const(2), Int, Bool) === Union{}
+@test setfield!_tfunc(Base.RefValue{Any}, String, Int) === Union{}
+@test setfield!_tfunc(Some{Any}, Const(:value), Int) === Union{}
+@test setfield!_tfunc(Some, Const(:value), Int) === Union{}
+@test setfield!_tfunc(Some{Any}, Const(1), Int) === Union{}
+@test setfield!_tfunc(Some, Const(1), Int) === Union{}
+@test setfield!_tfunc(Some{Any}, Symbol, Int) === Union{}
+@test setfield!_tfunc(Some, Symbol, Int) === Union{}
+@test setfield!_tfunc(Some{Any}, Int, Int) === Union{}
+@test setfield!_tfunc(Some, Int, Int) === Union{}
+@test setfield!_tfunc(Const(@__MODULE__), Const(:v), Int) === Union{}
+@test setfield!_tfunc(Const(@__MODULE__), Int, Int) === Union{}
+@test setfield!_tfunc(Module, Const(:v), Int) === Union{}
+@test setfield!_tfunc(ABCDconst, Const(:a), Any) === Union{}
+@test setfield!_tfunc(ABCDconst, Const(:b), Any) === Union{}
+@test setfield!_tfunc(ABCDconst, Const(:d), Any) === Union{}
+@test setfield!_tfunc(ABCDconst, Const(1), Any) === Union{}
+@test setfield!_tfunc(ABCDconst, Const(2), Any) === Union{}
+@test setfield!_tfunc(ABCDconst, Const(4), Any) === Union{}
+@test setfield!_nothrow(Base.RefValue{Int}, Const(:x), Int)
+@test setfield!_nothrow(Base.RefValue{Int}, Const(1), Int)
+@test setfield!_nothrow(Base.RefValue{Any}, Const(:x), Int)
+@test setfield!_nothrow(Base.RefValue{Any}, Const(1), Int)
+@test setfield!_nothrow(XY{Any,Any}, Const(:x), Int)
+@test setfield!_nothrow(XY{Any,Any}, Const(:x), Any)
+@test setfield!_nothrow(XY{Int,Float64}, Const(:x), Int)
+@test setfield!_nothrow(ABCDconst, Const(:c), Any)
+@test setfield!_nothrow(ABCDconst, Const(3), Any)
+@test !setfield!_nothrow(XY{Int,Float64}, Symbol, Any)
+@test !setfield!_nothrow(XY{Int,Float64}, Int, Any)
+@test !setfield!_nothrow(Base.RefValue{Int}, Const(:x), Any)
+@test !setfield!_nothrow(Base.RefValue{Int}, Const(1), Any)
+@test !setfield!_nothrow(Any[Base.RefValue{Any}, Const(:x), Int, Symbol])
+@test !setfield!_nothrow(Base.RefValue{Any}, Symbol, Int)
+@test !setfield!_nothrow(Base.RefValue{Any}, Int, Int)
+@test !setfield!_nothrow(XY{Int,Float64}, Const(:y), Int)
+@test !setfield!_nothrow(XY{Int,Float64}, Symbol, Int)
+@test !setfield!_nothrow(XY{Int,Float64}, Int, Int)
+@test !setfield!_nothrow(ABCDconst, Const(:a), Any)
+@test !setfield!_nothrow(ABCDconst, Const(:b), Any)
+@test !setfield!_nothrow(ABCDconst, Const(:d), Any)
+@test !setfield!_nothrow(ABCDconst, Symbol, Any)
+@test !setfield!_nothrow(ABCDconst, Const(1), Any)
+@test !setfield!_nothrow(ABCDconst, Const(2), Any)
+@test !setfield!_nothrow(ABCDconst, Const(4), Any)
+@test !setfield!_nothrow(ABCDconst, Int, Any)
+@test !setfield!_nothrow(Union{Base.RefValue{Any},Some{Any}}, Const(:x), Int)
+@test !setfield!_nothrow(Union{Base.RefValue,Some{Any}}, Const(:x), Int)
+@test !setfield!_nothrow(Union{Base.RefValue{Any},Some{Any}}, Const(1), Int)
+@test !setfield!_nothrow(Union{Base.RefValue,Some{Any}}, Const(1), Int)
+@test !setfield!_nothrow(Union{Base.RefValue{Any},Some{Any}}, Symbol, Int)
+@test !setfield!_nothrow(Union{Base.RefValue,Some{Any}}, Symbol, Int)
+@test !setfield!_nothrow(Union{Base.RefValue{Any},Some{Any}}, Int, Int)
+@test !setfield!_nothrow(Union{Base.RefValue,Some{Any}}, Int, Int)
+@test !setfield!_nothrow(Any, Symbol, Int)
+@test !setfield!_nothrow(Any, Int, Int)
+@test !setfield!_nothrow(Any, Any, Int)
+
 struct Foo_22708
     x::Ptr{Foo_22708}
 end
@@ -3181,7 +3287,7 @@ end
 @test Core.Compiler.return_type(apply26826, Tuple{typeof(===), Any, Vararg}) == Bool
 @test Core.Compiler.return_type(apply26826, Tuple{typeof(===), Any, Any, Vararg}) == Bool
 @test Core.Compiler.return_type(apply26826, Tuple{typeof(===), Any, Any, Any, Vararg}) == Union{}
-@test Core.Compiler.return_type(apply26826, Tuple{typeof(setfield!), Vararg{Symbol}}) == Symbol
+@test Core.Compiler.return_type(apply26826, Tuple{typeof(setfield!), Vararg{Symbol}}) == Union{}
 @test Core.Compiler.return_type(apply26826, Tuple{typeof(setfield!), Any, Vararg{Symbol}}) == Symbol
 @test Core.Compiler.return_type(apply26826, Tuple{typeof(setfield!), Any, Symbol, Vararg{Integer}}) == Integer
 @test Core.Compiler.return_type(apply26826, Tuple{typeof(setfield!), Any, Symbol, Integer, Vararg}) == Integer