compiler: ignore struct field tags for type conversion

    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

From-SVN: r248248

diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index f7e19d32bd6c7b07a4fee734a9e1a6d2116cbf24..2a4aa2dbb0389c9d130d7c5ea9f55412e7ffbbec 100644 (file)
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -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.

diff --git a/gcc/go/gofrontend/types.cc b/gcc/go/gofrontend/types.cc
index 8d542de1b3c24bbe0b602296daffc79b15bc201f..053e71d6bfab83e38eced1642b4ca2ffc8644ca9 100644 (file)
--- a/gcc/go/gofrontend/types.cc
+++ b/gcc/go/gofrontend/types.cc
@@ -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)
     {
@@ -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:
@@ -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.
@@ -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
@@ -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)
@@ -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;
@@ -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");
@@ -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");
@@ -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_)
@@ -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())
@@ -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_)
@@ -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.
@@ -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_);
@@ -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
@@ -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;
     }
 
@@ -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)
            {

diff --git a/gcc/go/gofrontend/types.h b/gcc/go/gofrontend/types.h
index bae7fd3a541092889e2d8b749d73f6d3812c0d25..bfc0a8ba46a4e42f9ae1b4bd8b2e26e99f9fad8a 100644 (file)
--- a/gcc/go/gofrontend/types.h
+++ b/gcc/go/gofrontend/types.h
@@ -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.
@@ -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
@@ -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.
@@ -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*
@@ -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*
@@ -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*
@@ -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.