[gcc r12-2599] d: Generate Object class if it doesn't exist during TypeInfo emission (PR101672)

[Iain Buclaw <ibuclaw@gcc.gnu.org>]

https://gcc.gnu.org/g:3c13cf479ba81c4d29b202e9b8c6a7f0031a8b20

commit r12-2599-g3c13cf479ba81c4d29b202e9b8c6a7f0031a8b20
Author: Iain Buclaw <ibuclaw@gdcproject.org>
Date:   Mon Jul 26 20:01:29 2021 +0200

    d: Generate Object class if it doesn't exist during TypeInfo emission (PR101672)
    
    Having a stub will prevent errors from occuring when compiling D code
    with an empty object.d.  Though if it were to actually be used
    implicitly then an error should occur.
    
            PR d/101672
    
    gcc/d/ChangeLog:
    
            * typeinfo.cc (make_frontend_typeinfo): Generate Object class if it
            doesn't exist.
            (check_typeinfo_type): Don't warn if there's no location.
    
    gcc/testsuite/ChangeLog:
    
            * gdc.dg/pr100967.d: Update test.
            * gdc.dg/pr101672.d: New test.

Diff:
---
 gcc/d/typeinfo.cc               | 23 +++++++++++++++++++++--
 gcc/testsuite/gdc.dg/pr100967.d |  2 +-
 gcc/testsuite/gdc.dg/pr101672.d | 19 +++++++++++++++++++
 3 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/gcc/d/typeinfo.cc b/gcc/d/typeinfo.cc
index 9d6464deb07..a1f0543d58e 100644
--- a/gcc/d/typeinfo.cc
+++ b/gcc/d/typeinfo.cc
@@ -205,12 +205,30 @@ make_frontend_typeinfo (Identifier *ident, ClassDeclaration *base = NULL)
   if (!object_module->_scope)
     object_module->importAll (NULL);
 
+  /* Object class doesn't exist, create a stub one that will cause an error if
+     used.  */
+  Loc loc = (object_module->md) ? object_module->md->loc : object_module->loc;
+  if (!base)
+    {
+      if (!ClassDeclaration::object)
+	{
+	  ClassDeclaration *object
+	    = ClassDeclaration::create (loc, Identifier::idPool ("Object"),
+					NULL, NULL, true);
+	  object->parent = object_module;
+	  object->members = new Dsymbols;
+	  object->storage_class |= STCtemp;
+	}
+
+      base = ClassDeclaration::object;
+    }
+
   /* Assignment of global typeinfo variables is managed by the ClassDeclaration
      constructor, so only need to new the declaration here.  */
-  Loc loc = (object_module->md) ? object_module->md->loc : object_module->loc;
   ClassDeclaration *tinfo = ClassDeclaration::create (loc, ident, NULL, NULL,
 						      true);
   tinfo->parent = object_module;
+  tinfo->members = new Dsymbols;
   dsymbolSemantic (tinfo, object_module->_scope);
   tinfo->baseClass = base;
   /* This is a compiler generated class, and shouldn't be mistaken for being
@@ -1316,6 +1334,7 @@ public:
     tree type = tinfo_types[get_typeinfo_kind (tid->tinfo)];
     gcc_assert (type != NULL_TREE);
 
+    /* Built-in typeinfo will be referenced as one-only.  */
     tid->csym = declare_extern_var (ident, type);
     DECL_LANG_SPECIFIC (tid->csym) = build_lang_decl (tid);
 
@@ -1400,7 +1419,7 @@ check_typeinfo_type (const Loc &loc, Scope *sc)
       /* If TypeInfo has not been declared, warn about each location once.  */
       static Loc warnloc;
 
-      if (!warnloc.equals (loc))
+      if (loc.filename && !warnloc.equals (loc))
 	{
 	  error_at (make_location_t (loc),
 		    "%<object.TypeInfo%> could not be found, "
diff --git a/gcc/testsuite/gdc.dg/pr100967.d b/gcc/testsuite/gdc.dg/pr100967.d
index 582ad582676..bb83c299ced 100644
--- a/gcc/testsuite/gdc.dg/pr100967.d
+++ b/gcc/testsuite/gdc.dg/pr100967.d
@@ -1,7 +1,7 @@
 // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100967
 // { dg-do compile }
 
-module object; // { dg-error "class object.TypeInfo missing or corrupt object.d" }
+module object;
 
 extern(C) int main()
 {
diff --git a/gcc/testsuite/gdc.dg/pr101672.d b/gcc/testsuite/gdc.dg/pr101672.d
new file mode 100644
index 00000000000..292fd761fb1
--- /dev/null
+++ b/gcc/testsuite/gdc.dg/pr101672.d
@@ -0,0 +1,19 @@
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101672
+// { dg-do compile }
+
+module object;
+
+interface I101672
+{
+    static int i101672;
+}
+
+class A101672 : I101672 // { dg-error "class object.A101672 missing or corrupt object.d" }
+{
+    static int a101672;
+}
+
+class B101672 : A101672
+{
+    static int b101672;
+}