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some tricks with types
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@vtjnash
vtjnash committed Mar 3, 2023
1 parent 51db8af commit fa2f102
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Showing 4 changed files with 221 additions and 2 deletions.
7 changes: 7 additions & 0 deletions base/essentials.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -382,6 +382,13 @@ function rename_unionall(@nospecialize(u))
return UnionAll(nv, body{nv})
end

# expand diagonal TypeVars to be unconstrained
function diagonalize_unionall(T::UnionAll)
body = ccall(:jl_diagonalize_var, Any, (Any, Any), T.body, T.var)
body === T.body && return T
return UnionAll(T.var, body)
end

function isvarargtype(@nospecialize(t))
return isa(t, Core.TypeofVararg)
end
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213 changes: 212 additions & 1 deletion src/gf.c
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Expand Up @@ -1397,9 +1397,220 @@ static int get_intersect_visitor(jl_typemap_entry_t *oldentry, struct typemap_in
return 1;
}


JL_DLLEXPORT jl_value_t *jl_diagonalize_var(jl_value_t *body, jl_tvar_t *tv);

static jl_value_t *diagonalize_var(jl_value_t *type, jl_tvar_t *tv, jl_unionall_t **result)
{
// we must replace each covariant occurrence of newvar with a different newvar2<:newvar (diagonal rule)
if (type == (jl_value_t*)tv) {
*result = (jl_unionall_t*)jl_new_struct(jl_unionall_type, tv, *result);
jl_tvar_t *newvar = jl_new_typevar(tv->name, tv->lb, (jl_value_t*)tv);
(*result)->var = newvar;
jl_gc_wb(*result, newvar);
type = (jl_value_t*)newvar;
}
else if (jl_is_unionall(type)) {
jl_value_t *body = ((jl_unionall_t*)type)->body;
jl_tvar_t *var = ((jl_unionall_t*)type)->var;
if (var != tv) {
jl_value_t *newbody = diagonalize_var(body, tv, result);
jl_value_t *newvar = NULL;
JL_GC_PUSH2(&newbody, &newvar);
if (body == newbody || jl_has_typevar(newbody, var)) {
if (body != newbody) {
newbody = jl_new_struct(jl_unionall_type, var, newbody);
type = newbody;
}
// n.b. we do not widen lb, since that would be the wrong direction
newvar = diagonalize_var(var->ub, tv, result);
if (newvar != var->ub) {
newvar = (jl_value_t*)jl_new_typevar(var->name, tv->lb, newvar);
newbody = jl_apply_type1(newbody, newvar);
newbody = jl_type_unionall((jl_tvar_t*)newvar, newbody);
type = newbody;
}
}
JL_GC_POP();
}
}
else if (jl_is_uniontype(type)) {
jl_value_t *a = ((jl_uniontype_t*)type)->a;
jl_value_t *b = ((jl_uniontype_t*)type)->b;
jl_value_t *newa = NULL;
jl_value_t *newb = NULL;
JL_GC_PUSH2(&newa, &newb);
newa = diagonalize_var(a, tv, result);
newb = diagonalize_var(b, tv, result);
if (newa != a || newb != b)
type = jl_new_struct(jl_uniontype_type, newa, newb);
JL_GC_POP();
}
else if (jl_is_vararg(type)) {
jl_value_t *t = jl_unwrap_vararg(type);
//jl_unionall_t *bounds = (jl_unionall_t*)jl_nothing;
//jl_value_t *newt = NULL;
//JL_GC_PUSH1(&bounds, &newt);
//newt = diagonalize_var(t, tv, &bounds);
jl_value_t *newt = t;
if (t == (jl_value_t*)tv) // this is pathetic, but otherwise rewrap_unionall will fail us
newt = jl_new_struct(jl_uniontype_type, newt, newt);
JL_GC_PUSH1(&newt);
newt = jl_diagonalize_var(newt, tv);
if (t != newt) {
// newt = jl_rewrap_unionall(newt, (jl_value_t*)bounds);
// while (jl_is_typevar(newt)) // this is pathetic, but rewrap_unionall might have failed us
// newt = ((jl_tvar_t*)newt)->ub;
jl_value_t *newn = jl_unwrap_vararg_num(type);
type = jl_new_struct(jl_vararg_type, newt, newn);
}
JL_GC_POP();
}
else if (jl_is_datatype(type)) {
if (jl_is_tuple_type(type)) {
jl_svec_t *newparams = NULL;
JL_GC_PUSH1(&newparams);
for (size_t i = jl_nparams(type); i-- > 0; ) {
jl_value_t *elt = jl_tparam(type, i);
jl_value_t *newelt = diagonalize_var(elt, tv, result);
if (elt != newelt) {
if (!newparams) {
newparams = (jl_svec_t*)newelt; // temporary root
newparams = jl_svec_copy(((jl_datatype_t*)type)->parameters);
}
jl_svecset(newparams, i, newelt);
}
}
if (newparams)
type = (jl_value_t*)jl_apply_tuple_type(newparams);
JL_GC_POP();
}
}
return type;
}


JL_DLLEXPORT jl_value_t *jl_diagonalize_var(jl_value_t *body, jl_tvar_t *tv)
{
jl_unionall_t *bounds = NULL;
JL_GC_PUSH1(&bounds);
jl_value_t *newbody = diagonalize_var(body, tv, &bounds);
if (bounds) {
// aka jl_rewrap_unionall(body, bounds)
jl_unionall_t *bb = bounds;
while (bb->body != NULL)
bb = (jl_unionall_t*)bb->body;
bb->body = newbody;
jl_gc_wb(bb, newbody);
newbody = (jl_value_t*)bounds;
}
JL_GC_POP();
return newbody;
}


// compute a minimal typejoin on a tupletype, which removes all covariant Unions
// by type widening (e.g. removes depth=0 subtyping and intersection decision points)
JL_DLLEXPORT jl_value_t *typejoin_ttype(jl_value_t *type)
{
if (jl_is_unionall(type)) {
jl_value_t *body = ((jl_unionall_t*)type)->body;
jl_value_t *uw = jl_unwrap_unionall(body);
if (jl_is_datatype(uw) && ((jl_datatype_t*)uw)->name->wrapper == type)
return type;
jl_tvar_t *var = ((jl_unionall_t*)type)->var;
jl_value_t *newbody = typejoin_ttype(body);
if (body != newbody) {
uw = jl_unwrap_unionall(newbody);
if (jl_is_datatype(uw) && ((jl_datatype_t*)uw)->name->wrapper == newbody)
return newbody;
}
jl_value_t *newvar = NULL;
JL_GC_PUSH2(&newvar, &type);
if (body == newbody || jl_has_typevar(newbody, var)) {
if (body != newbody) {
type = newbody;
type = jl_new_struct(jl_unionall_type, var, type);
}
newvar = typejoin_ttype(var->ub);
if (newvar != var->ub || var->lb != jl_bottom_type) {
newvar = (jl_value_t*)jl_new_typevar(var->name, jl_bottom_type, newvar);
type = jl_apply_type1(type, newvar);
if (var_occurs_invariant(body, var, 0) && !var_occurs_invariant(newbody, var, 0))
type = jl_diagonalize_var(type, (jl_tvar_t*)newvar);
type = jl_type_unionall((jl_tvar_t*)newvar, type);
}
}
JL_GC_POP();
}
else if (jl_is_uniontype(type)) {
jl_value_t *a = ((jl_uniontype_t*)type)->a;
jl_value_t *b = ((jl_uniontype_t*)type)->b;
jl_value_t *newa = NULL;
jl_value_t *newb = NULL;
JL_GC_PUSH2(&newa, &newb);
newa = typejoin_ttype(a);
newb = typejoin_ttype(b);
type = (jl_value_t*)jl_any_type;
if (newa == newb) {
type = newa;
}
else {
// TODO: change this to find the common supertype here
newa = jl_unwrap_unionall(newa);
newb = jl_unwrap_unionall(newb);
if (jl_is_datatype(newa) && jl_is_datatype(newb)) {
jl_typename_t *namea = ((jl_datatype_t*)newa)->name;
jl_typename_t *nameb = ((jl_datatype_t*)newb)->name;
if (namea == nameb)
type = namea->wrapper;
}
}
JL_GC_POP();
}
else if (jl_is_vararg(type)) {
jl_value_t *t = jl_unwrap_vararg(type);
jl_value_t *n = jl_unwrap_vararg_num(type);
jl_value_t *newt = NULL;
jl_value_t *newn = NULL;
JL_GC_PUSH2(&newt, &newn);
newt = typejoin_ttype(t);
newn = typejoin_ttype(n);
if (t != newt || n != newn)
type = jl_new_struct(jl_vararg_type, newt, newn);
JL_GC_POP();
}
else if (jl_is_datatype(type)) {
if (jl_is_tuple_type(type)) {
jl_svec_t *newparams = NULL;
JL_GC_PUSH1(&newparams);
size_t i, np = jl_nparams(type);
for (i = 0; i < np; i++) {
jl_value_t *elt = jl_tparam(type, i);
jl_value_t *newelt = typejoin_ttype(elt);
if (elt != newelt) {
if (!newparams) {
newparams = (jl_svec_t*)newelt; // temporary root
newparams = jl_svec_copy(((jl_datatype_t*)type)->parameters);
}
jl_svecset(newparams, i, newelt);
}
}
if (newparams)
type = (jl_value_t*)jl_apply_tuple_type(newparams);
JL_GC_POP();
}
//else if (!((jl_datatype_t*)type)->isconcretetype) {
// type = ((jl_datatype_t*)type)->name->wrapper;
//}
}
return type;
}

static jl_value_t *get_intersect_matches(jl_typemap_t *defs, jl_typemap_entry_t *newentry)
{
jl_tupletype_t *type = newentry->sig;
jl_tupletype_t *type = (jl_tupletype_t*)typejoin_ttype((jl_value_t*)newentry->sig);
//type = newentry->sig;
jl_tupletype_t *ttypes = (jl_tupletype_t*)jl_unwrap_unionall((jl_value_t*)type);
size_t l = jl_nparams(ttypes);
jl_value_t *va = NULL;
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1 change: 1 addition & 0 deletions src/julia_internal.h
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Expand Up @@ -680,6 +680,7 @@ JL_DLLEXPORT void jl_method_table_insert(jl_methtable_t *mt, jl_method_t *method
jl_datatype_t *jl_mk_builtin_func(jl_datatype_t *dt, const char *name, jl_fptr_args_t fptr) JL_GC_DISABLED;
int jl_obviously_unequal(jl_value_t *a, jl_value_t *b);
JL_DLLEXPORT jl_array_t *jl_find_free_typevars(jl_value_t *v);
int var_occurs_invariant(jl_value_t *v, jl_tvar_t *var, int inv) JL_NOTSAFEPOINT;
int jl_has_fixed_layout(jl_datatype_t *t);
JL_DLLEXPORT int jl_struct_try_layout(jl_datatype_t *dt);
JL_DLLEXPORT int jl_type_mappable_to_c(jl_value_t *ty);
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2 changes: 1 addition & 1 deletion src/subtype.c
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Expand Up @@ -826,7 +826,7 @@ static int var_occurs_inside(jl_value_t *v, jl_tvar_t *var, int inside, int want

typedef int (*tvar_callback)(void*, int8_t, jl_stenv_t *, int);

static int var_occurs_invariant(jl_value_t *v, jl_tvar_t *var, int inv) JL_NOTSAFEPOINT
int var_occurs_invariant(jl_value_t *v, jl_tvar_t *var, int inv) JL_NOTSAFEPOINT
{
return var_occurs_inside(v, var, 0, 1);
}
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