From e5f47972f63702afba99c291b81ff5a61506699f Mon Sep 17 00:00:00 2001
From: Boris Kolpackov <boris@codesynthesis.com>
Date: Thu, 18 Jun 2020 08:25:50 +0200
Subject: Work around GCC bug 86441

---
 odb/semantics/class.cxx | 36 ++++++++++++++++++++++++++++++++----
 odb/validator.cxx       |  3 +++
 2 files changed, 35 insertions(+), 4 deletions(-)

(limited to 'odb')

diff --git a/odb/semantics/class.cxx b/odb/semantics/class.cxx
index c03de92..acecb35 100644
--- a/odb/semantics/class.cxx
+++ b/odb/semantics/class.cxx
@@ -25,11 +25,39 @@ namespace semantics
   {
     tree t (tree_node ());
 
-    // TYPE_HAS_DEFAULT_CONSTRUCTOR() returns true if we have a
-    // deleted default ctor. locate_ctor(), on the other hand,
-    // returns NULL_TREE in this case.
+    // TYPE_HAS_DEFAULT_CONSTRUCTOR() returns true if we have a deleted
+    // default ctor. locate_ctor(), on the other hand, returns NULL_TREE in
+    // this case.
     //
-    return TYPE_HAS_DEFAULT_CONSTRUCTOR (t) && locate_ctor (t) != NULL_TREE;
+    if (TYPE_HAS_DEFAULT_CONSTRUCTOR (t))
+    {
+#if BUILDING_GCC_MAJOR >= 8
+
+      // Work around GCC bug 86441. Essentially, we should not trigger an
+      // instantiation or completion of the default ctor. As a result, we will
+      // assume that if we have a lazy default ctor, it is not implicitly
+      // deleted.
+      //
+      if (CLASSTYPE_LAZY_DEFAULT_CTOR (t))
+        return true;
+
+      for (ovl_iterator i (CLASSTYPE_CONSTRUCTORS (t)); i; ++i)
+      {
+        tree f (*i);
+
+        if (TREE_CODE (f) == FUNCTION_DECL && DECL_DELETED_FN (f))
+          continue;
+
+        if (default_ctor_p (f))
+          return true;
+      }
+#else
+      return locate_ctor (t) != NULL_TREE;
+#endif
+
+    }
+
+    return false;
   }
 
   bool class_::
diff --git a/odb/validator.cxx b/odb/validator.cxx
index 9c20714..bf9aa6b 100644
--- a/odb/validator.cxx
+++ b/odb/validator.cxx
@@ -1655,6 +1655,9 @@ namespace
             // temporarily redirect diagnostics to /dev/null, which is
             // where asm_out_file points to (see plugin.cxx).
             //
+            // Needless to say, this is very hacky and we should quickly fail
+            // (as we do below) if there were errors.
+            //
             int ec (errorcount);
             FILE* s (global_dc->printer->buffer->stream);
             global_dc->printer->buffer->stream = asm_out_file;
-- 
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