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compiler: ignore struct field tags for type conversion
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    Go 1.8 includes a language change (https://golang.org/doc/go1.8#language):
    in an explicit conversion from one struct type to another, any field
    tags are ignored.
    
    This CL implements this language change in the gofrontend.  The tests
    for this are in the gc testsuite, which will be copied into the gccgo
    repository in due course.
    
    Updates golang/go#16085.
    
    Reviewed-on: https://go-review.googlesource.com/43614


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@248248 138bc75d-0d04-0410-961f-82ee72b054a4
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ian committed May 18, 2017
1 parent 04ba4f8 commit f7545bf
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Showing 3 changed files with 101 additions and 57 deletions.
2 changes: 1 addition & 1 deletion gcc/go/gofrontend/MERGE
View file
Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
ba68a42618d1e8516e38da093d3af731d7fd4f06
369e1efe19adfc5393d2235992327f39360e0554

The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.
123 changes: 73 additions & 50 deletions gcc/go/gofrontend/types.cc
View file
Original file line number Diff line number Diff line change
Expand Up @@ -316,6 +316,16 @@ Type::do_traverse(Traverse*)
bool
Type::are_identical(const Type* t1, const Type* t2, bool errors_are_identical,
std::string* reason)
{
return Type::are_identical_cmp_tags(t1, t2, COMPARE_TAGS,
errors_are_identical, reason);
}

// Like are_identical, but with a CMP_TAGS parameter.

bool
Type::are_identical_cmp_tags(const Type* t1, const Type* t2, Cmp_tags cmp_tags,
bool errors_are_identical, std::string* reason)
{
if (t1 == NULL || t2 == NULL)
{
Expand Down Expand Up @@ -387,31 +397,33 @@ Type::are_identical(const Type* t1, const Type* t2, bool errors_are_identical,
case TYPE_FUNCTION:
return t1->function_type()->is_identical(t2->function_type(),
false,
cmp_tags,
errors_are_identical,
reason);

case TYPE_POINTER:
return Type::are_identical(t1->points_to(), t2->points_to(),
errors_are_identical, reason);
return Type::are_identical_cmp_tags(t1->points_to(), t2->points_to(),
cmp_tags, errors_are_identical,
reason);

case TYPE_STRUCT:
return t1->struct_type()->is_identical(t2->struct_type(),
return t1->struct_type()->is_identical(t2->struct_type(), cmp_tags,
errors_are_identical);

case TYPE_ARRAY:
return t1->array_type()->is_identical(t2->array_type(),
return t1->array_type()->is_identical(t2->array_type(), cmp_tags,
errors_are_identical);

case TYPE_MAP:
return t1->map_type()->is_identical(t2->map_type(),
return t1->map_type()->is_identical(t2->map_type(), cmp_tags,
errors_are_identical);

case TYPE_CHANNEL:
return t1->channel_type()->is_identical(t2->channel_type(),
return t1->channel_type()->is_identical(t2->channel_type(), cmp_tags,
errors_are_identical);

case TYPE_INTERFACE:
return t1->interface_type()->is_identical(t2->interface_type(),
return t1->interface_type()->is_identical(t2->interface_type(), cmp_tags,
errors_are_identical);

case TYPE_CALL_MULTIPLE_RESULT:
Expand Down Expand Up @@ -735,23 +747,26 @@ Type::are_convertible(const Type* lhs, const Type* rhs, std::string* reason)
return true;

// The types are convertible if they have identical underlying
// types.
// types, ignoring struct field tags.
if ((lhs->named_type() != NULL || rhs->named_type() != NULL)
&& Type::are_identical(lhs->base(), rhs->base(), true, reason))
&& Type::are_identical_cmp_tags(lhs->base(), rhs->base(), IGNORE_TAGS,
true, reason))
return true;

// The types are convertible if they are both unnamed pointer types
// and their pointer base types have identical underlying types.
// and their pointer base types have identical underlying types,
// ignoring struct field tags.
if (lhs->named_type() == NULL
&& rhs->named_type() == NULL
&& lhs->points_to() != NULL
&& rhs->points_to() != NULL
&& (lhs->points_to()->named_type() != NULL
|| rhs->points_to()->named_type() != NULL)
&& Type::are_identical(lhs->points_to()->base(),
rhs->points_to()->base(),
true,
reason))
&& Type::are_identical_cmp_tags(lhs->points_to()->base(),
rhs->points_to()->base(),
IGNORE_TAGS,
true,
reason))
return true;

// Integer and floating point types are convertible to each other.
Expand Down Expand Up @@ -4502,7 +4517,7 @@ bool
Function_type::is_valid_redeclaration(const Function_type* t,
std::string* reason) const
{
if (!this->is_identical(t, false, true, reason))
if (!this->is_identical(t, false, COMPARE_TAGS, true, reason))
return false;

// A redeclaration of a function is required to use the same names
Expand Down Expand Up @@ -4580,7 +4595,7 @@ Function_type::is_valid_redeclaration(const Function_type* t,

bool
Function_type::is_identical(const Function_type* t, bool ignore_receiver,
bool errors_are_identical,
Cmp_tags cmp_tags, bool errors_are_identical,
std::string* reason) const
{
if (!ignore_receiver)
Expand All @@ -4595,8 +4610,8 @@ Function_type::is_identical(const Function_type* t, bool ignore_receiver,
}
if (r1 != NULL)
{
if (!Type::are_identical(r1->type(), r2->type(), errors_are_identical,
reason))
if (!Type::are_identical_cmp_tags(r1->type(), r2->type(), cmp_tags,
errors_are_identical, reason))
{
if (reason != NULL && !reason->empty())
*reason = "receiver: " + *reason;
Expand Down Expand Up @@ -4627,8 +4642,8 @@ Function_type::is_identical(const Function_type* t, bool ignore_receiver,
return false;
}

if (!Type::are_identical(p1->type(), p2->type(),
errors_are_identical, NULL))
if (!Type::are_identical_cmp_tags(p1->type(), p2->type(), cmp_tags,
errors_are_identical, NULL))
{
if (reason != NULL)
*reason = _("different parameter types");
Expand Down Expand Up @@ -4672,8 +4687,9 @@ Function_type::is_identical(const Function_type* t, bool ignore_receiver,
return false;
}

if (!Type::are_identical(res1->type(), res2->type(),
errors_are_identical, NULL))
if (!Type::are_identical_cmp_tags(res1->type(), res2->type(),
cmp_tags, errors_are_identical,
NULL))
{
if (reason != NULL)
*reason = _("different result types");
Expand Down Expand Up @@ -5803,7 +5819,7 @@ Struct_type::do_has_pointer() const
// Whether this type is identical to T.

bool
Struct_type::is_identical(const Struct_type* t,
Struct_type::is_identical(const Struct_type* t, Cmp_tags cmp_tags,
bool errors_are_identical) const
{
if (this->is_struct_incomparable_ != t->is_struct_incomparable_)
Expand All @@ -5822,20 +5838,23 @@ Struct_type::is_identical(const Struct_type* t,
if (pf1->field_name() != pf2->field_name())
return false;
if (pf1->is_anonymous() != pf2->is_anonymous()
|| !Type::are_identical(pf1->type(), pf2->type(),
errors_are_identical, NULL))
|| !Type::are_identical_cmp_tags(pf1->type(), pf2->type(), cmp_tags,
errors_are_identical, NULL))
return false;
if (!pf1->has_tag())
if (cmp_tags == COMPARE_TAGS)
{
if (pf2->has_tag())
return false;
}
else
{
if (!pf2->has_tag())
return false;
if (pf1->tag() != pf2->tag())
return false;
if (!pf1->has_tag())
{
if (pf2->has_tag())
return false;
}
else
{
if (!pf2->has_tag())
return false;
if (pf1->tag() != pf2->tag())
return false;
}
}
}
if (pf2 != fields2->end())
Expand Down Expand Up @@ -7061,10 +7080,11 @@ Array_type::int_length(int64_t* plen)
// Whether two array types are identical.

bool
Array_type::is_identical(const Array_type* t, bool errors_are_identical) const
Array_type::is_identical(const Array_type* t, Cmp_tags cmp_tags,
bool errors_are_identical) const
{
if (!Type::are_identical(this->element_type(), t->element_type(),
errors_are_identical, NULL))
if (!Type::are_identical_cmp_tags(this->element_type(), t->element_type(),
cmp_tags, errors_are_identical, NULL))
return false;

if (this->is_array_incomparable_ != t->is_array_incomparable_)
Expand Down Expand Up @@ -7986,12 +8006,14 @@ Map_type::do_verify()
// Whether two map types are identical.

bool
Map_type::is_identical(const Map_type* t, bool errors_are_identical) const
Map_type::is_identical(const Map_type* t, Cmp_tags cmp_tags,
bool errors_are_identical) const
{
return (Type::are_identical(this->key_type(), t->key_type(),
errors_are_identical, NULL)
&& Type::are_identical(this->val_type(), t->val_type(),
errors_are_identical, NULL));
return (Type::are_identical_cmp_tags(this->key_type(), t->key_type(),
cmp_tags, errors_are_identical, NULL)
&& Type::are_identical_cmp_tags(this->val_type(), t->val_type(),
cmp_tags, errors_are_identical,
NULL));
}

// Hash code.
Expand Down Expand Up @@ -8510,11 +8532,11 @@ Channel_type::do_hash_for_method(Gogo* gogo) const
// Whether this type is the same as T.

bool
Channel_type::is_identical(const Channel_type* t,
Channel_type::is_identical(const Channel_type* t, Cmp_tags cmp_tags,
bool errors_are_identical) const
{
if (!Type::are_identical(this->element_type(), t->element_type(),
errors_are_identical, NULL))
if (!Type::are_identical_cmp_tags(this->element_type(), t->element_type(),
cmp_tags, errors_are_identical, NULL))
return false;
return (this->may_send_ == t->may_send_
&& this->may_receive_ == t->may_receive_);
Expand Down Expand Up @@ -8920,7 +8942,7 @@ Interface_type::is_unexported_method(Gogo* gogo, const std::string& name) const
// Whether this type is identical with T.

bool
Interface_type::is_identical(const Interface_type* t,
Interface_type::is_identical(const Interface_type* t, Cmp_tags cmp_tags,
bool errors_are_identical) const
{
// If methods have not been finalized, then we are asking whether
Expand Down Expand Up @@ -8951,8 +8973,8 @@ Interface_type::is_identical(const Interface_type* t,
if (p1 == this->all_methods_->end())
break;
if (p1->name() != p2->name()
|| !Type::are_identical(p1->type(), p2->type(),
errors_are_identical, NULL))
|| !Type::are_identical_cmp_tags(p1->type(), p2->type(), cmp_tags,
errors_are_identical, NULL))
break;
}

Expand Down Expand Up @@ -9150,7 +9172,8 @@ Interface_type::implements_interface(const Type* t, std::string* reason) const
Function_type* m_fn_type = m->type()->function_type();
go_assert(p_fn_type != NULL && m_fn_type != NULL);
std::string subreason;
if (!p_fn_type->is_identical(m_fn_type, true, true, &subreason))
if (!p_fn_type->is_identical(m_fn_type, true, COMPARE_TAGS, true,
&subreason))
{
if (reason != NULL)
{
Expand Down
33 changes: 27 additions & 6 deletions gcc/go/gofrontend/types.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -568,6 +568,22 @@ class Type
are_identical(const Type* lhs, const Type* rhs, bool errors_are_identical,
std::string* reason);

// An argument to are_identical_cmp_tags, indicating whether or not
// to compare struct field tags.
enum Cmp_tags {
COMPARE_TAGS,
IGNORE_TAGS
};

// Return true if two types are identical. This is like the
// are_identical function, but also takes a CMP_TAGS argument
// indicating whether to compare struct tags. Otherwise the
// parameters are as for are_identical.
static bool
are_identical_cmp_tags(const Type* lhs, const Type* rhs,
Cmp_tags, bool errors_are_identical,
std::string* reason);

// Return true if two types are compatible for use in a binary
// operation, other than a shift, comparison, or channel send. This
// is an equivalence relation.
Expand Down Expand Up @@ -1899,7 +1915,7 @@ class Function_type : public Type
// Whether this type is the same as T.
bool
is_identical(const Function_type* t, bool ignore_receiver,
bool errors_are_identical, std::string*) const;
Cmp_tags, bool errors_are_identical, std::string*) const;

// Record that this is a varargs function.
void
Expand Down Expand Up @@ -2293,7 +2309,8 @@ class Struct_type : public Type

// Whether this type is identical with T.
bool
is_identical(const Struct_type* t, bool errors_are_identical) const;
is_identical(const Struct_type* t, Cmp_tags,
bool errors_are_identical) const;

// Return whether NAME is a local field which is not exported. This
// is only used for better error reporting.
Expand Down Expand Up @@ -2495,7 +2512,8 @@ class Array_type : public Type

// Whether this type is identical with T.
bool
is_identical(const Array_type* t, bool errors_are_identical) const;
is_identical(const Array_type* t, Cmp_tags,
bool errors_are_identical) const;

// Return an expression for the pointer to the values in an array.
Expression*
Expand Down Expand Up @@ -2656,7 +2674,8 @@ class Map_type : public Type

// Whether this type is identical with T.
bool
is_identical(const Map_type* t, bool errors_are_identical) const;
is_identical(const Map_type* t, Cmp_tags,
bool errors_are_identical) const;

// Import a map type.
static Map_type*
Expand Down Expand Up @@ -2773,7 +2792,8 @@ class Channel_type : public Type

// Whether this type is identical with T.
bool
is_identical(const Channel_type* t, bool errors_are_identical) const;
is_identical(const Channel_type* t, Cmp_tags,
bool errors_are_identical) const;

// Import a channel type.
static Channel_type*
Expand Down Expand Up @@ -2883,7 +2903,8 @@ class Interface_type : public Type
// Whether this type is identical with T. REASON is as in
// implements_interface.
bool
is_identical(const Interface_type* t, bool errors_are_identical) const;
is_identical(const Interface_type* t, Cmp_tags,
bool errors_are_identical) const;

// Whether we can assign T to this type. is_identical is known to
// be false.
Expand Down

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