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compiler: treat notinheap types as not being pointers

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By definition, a type is marked notinheap doesn't contain any pointers
that the garbage collector cares about, and neither does a pointer to
such a type.  Change the type descriptors to consistently treat such
types as not being pointers, by setting ptrdata to 0 and gcdata to nil.

Change-Id: Id8466555ec493456ff5ff09f1670551414619bd2
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/384118
Trust: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
This commit is contained in:
Ian Lance Taylor 2022-02-08 20:22:32 -08:00
parent f3ffea93ef
commit 70feb6839f
4 changed files with 31 additions and 8 deletions
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2
gcc/go/gofrontend/MERGE
View file

@ -1,4 +1,4 @@
3b1e46937d11b043d0986a3dfefaee27454c3da0
7dffb933d33ff288675c8094d05c31b35cbf7e4d
The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.

7
gcc/go/gofrontend/gogo.cc
View file

@ -8869,10 +8869,13 @@ Named_object::get_backend(Gogo* gogo, std::vector<Bexpression*>& const_decls,
{
named_type->
type_descriptor_pointer(gogo, Linemap::predeclared_location());
named_type->gc_symbol_pointer(gogo);
Type* pn = Type::make_pointer_type(named_type);
pn->type_descriptor_pointer(gogo, Linemap::predeclared_location());
pn->gc_symbol_pointer(gogo);
if (named_type->in_heap())
{
named_type->gc_symbol_pointer(gogo);
pn->gc_symbol_pointer(gogo);
}
}
}
break;

25
gcc/go/gofrontend/types.cc
View file

@ -2513,13 +2513,18 @@ Type::type_descriptor_constructor(Gogo* gogo, int runtime_type_kind,
Expression_list* vals = new Expression_list();
vals->reserve(12);
if (!this->has_pointer())
bool has_pointer;
if (name != NULL)
has_pointer = name->has_pointer();
else
has_pointer = this->has_pointer();
if (!has_pointer)
runtime_type_kind |= RUNTIME_TYPE_KIND_NO_POINTERS;
if (this->is_direct_iface_type())
runtime_type_kind |= RUNTIME_TYPE_KIND_DIRECT_IFACE;
int64_t ptrsize;
int64_t ptrdata;
if (this->needs_gcprog(gogo, &ptrsize, &ptrdata))
if (has_pointer && this->needs_gcprog(gogo, &ptrsize, &ptrdata))
runtime_type_kind |= RUNTIME_TYPE_KIND_GC_PROG;
Struct_field_list::const_iterator p = fields->begin();
@ -2530,7 +2535,10 @@ Type::type_descriptor_constructor(Gogo* gogo, int runtime_type_kind,
++p;
go_assert(p->is_field_name("ptrdata"));
type_info = Expression::TYPE_INFO_DESCRIPTOR_PTRDATA;
vals->push_back(Expression::make_type_info(this, type_info));
if (has_pointer)
vals->push_back(Expression::make_type_info(this, type_info));
else
vals->push_back(Expression::make_integer_ul(0, p->type(), bloc));
++p;
go_assert(p->is_field_name("hash"));
@ -2576,7 +2584,12 @@ Type::type_descriptor_constructor(Gogo* gogo, int runtime_type_kind,
++p;
go_assert(p->is_field_name("gcdata"));
vals->push_back(Expression::make_gc_symbol(this));
if (has_pointer)
vals->push_back(Expression::make_gc_symbol(this));
else
vals->push_back(Expression::make_cast(p->type(),
Expression::make_nil(bloc),
bloc));
++p;
go_assert(p->is_field_name("string"));
@ -10894,6 +10907,10 @@ Named_type::do_verify()
bool
Named_type::do_has_pointer() const
{
// A type that is not in the heap has no pointers that we care about.
if (!this->in_heap_)
return false;
if (this->seen_)
return false;
this->seen_ = true;

5
gcc/go/gofrontend/types.h
View file

@ -2300,9 +2300,12 @@ class Pointer_type : public Type
do_verify()
{ return this->to_type_->verify(); }
// If this is a pointer to a type that can't be in the heap, then
// the garbage collector does not have to look at this, so pretend
// that this is not a pointer at all.
bool
do_has_pointer() const
{ return true; }
{ return this->to_type_->in_heap(); }
bool
do_compare_is_identity(Gogo*)