C++ PATCH for c++/88830 - ICE with abstract class

[Marek Polacek]

Here we were crashing because while the class C has a destructor, it hasn't yet
been declared at this point in maybe_emit_vtables, so CLASSTYPE_DESTRUCTOR is
null, so checking DECL_DEFAULTED_IN_CLASS_P crashed.  Fixed by checking
CLASSTYPE_LAZY_DESTRUCTOR first.

Bootstrapped/regtested on x86_64-linux, ok for trunk?

2019-01-13  Marek Polacek  <pola...@redhat.com>

        PR c++/88830 - ICE with abstract class.
        * decl2.c (maybe_emit_vtables): Check CLASSTYPE_LAZY_DESTRUCTOR.
        Fix formatting.

        * g++.dg/other/abstract7.C: New test.

diff --git gcc/cp/decl2.c gcc/cp/decl2.c
index e4cf4e0a361..7b656712471 100644
--- gcc/cp/decl2.c
+++ gcc/cp/decl2.c
@@ -2229,7 +2229,8 @@ maybe_emit_vtables (tree ctype)
      never get generated.  */
   if (CLASSTYPE_PURE_VIRTUALS (ctype)
       && TYPE_HAS_NONTRIVIAL_DESTRUCTOR (ctype)
-      && DECL_DEFAULTED_IN_CLASS_P(CLASSTYPE_DESTRUCTOR(ctype)))
+      && !CLASSTYPE_LAZY_DESTRUCTOR (ctype)
+      && DECL_DEFAULTED_IN_CLASS_P (CLASSTYPE_DESTRUCTOR (ctype)))
     note_vague_linkage_fn (CLASSTYPE_DESTRUCTOR(ctype));
 
   /* Since we're writing out the vtable here, also write the debug
diff --git gcc/testsuite/g++.dg/other/abstract7.C 
gcc/testsuite/g++.dg/other/abstract7.C
new file mode 100644
index 00000000000..95781602c95
--- /dev/null
+++ gcc/testsuite/g++.dg/other/abstract7.C
@@ -0,0 +1,14 @@
+// PR c++/88830
+
+struct a {
+  ~a();
+};
+class b {
+  virtual void c(int &);
+};
+class C : b {
+  void c(int &);
+  virtual int d() = 0;
+  a e;
+};
+void C::c(int &) {}