c++: 'this' adjustment for devirtualized call

My patch for 95719 made us do a better job of finding the actual virtual
function we want to call, but didn't update the 'this' pointer adjustment to
match.

	PR c++/100797
	PR c++/95719

gcc/cp/ChangeLog:

	* call.c (build_over_call): Adjust base_binfo in
	resolves_to_fixed_type_p case.

gcc/testsuite/ChangeLog:

	* g++.dg/inherit/virtual15.C: New test.

diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 3076fe67d5c33b92d6e9feab0604efc959506cee..bf524b50bc49f29b13f984e424a23c7275ecb024 100644 (file)
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -9152,18 +9152,32 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
          if (base_binfo == error_mark_node)
            return error_mark_node;
        }
-      tree converted_arg = build_base_path (PLUS_EXPR, arg,
-                                           base_binfo, 1, complain);
 
       /* If we know the dynamic type of the object, look up the final overrider
         in the BINFO.  */
       if (DECL_VINDEX (fn) && (flags & LOOKUP_NONVIRTUAL) == 0
          && resolves_to_fixed_type_p (arg))
        {
-         fn = lookup_vfn_in_binfo (DECL_VINDEX (fn), base_binfo);
-         flags |= LOOKUP_NONVIRTUAL;
+         tree ov = lookup_vfn_in_binfo (DECL_VINDEX (fn), base_binfo);
+
+         /* And unwind base_binfo to match.  If we don't find the type we're
+            looking for in BINFO_INHERITANCE_CHAIN, we're looking at diamond
+            inheritance; for now do a normal virtual call in that case.  */
+         tree octx = DECL_CONTEXT (ov);
+         tree obinfo = base_binfo;
+         while (obinfo && !SAME_BINFO_TYPE_P (BINFO_TYPE (obinfo), octx))
+           obinfo = BINFO_INHERITANCE_CHAIN (obinfo);
+         if (obinfo)
+           {
+             fn = ov;
+             base_binfo = obinfo;
+             flags |= LOOKUP_NONVIRTUAL;
+           }
        }
 
+      tree converted_arg = build_base_path (PLUS_EXPR, arg,
+                                           base_binfo, 1, complain);
+
       argarray[j++] = converted_arg;
       parm = TREE_CHAIN (parm);
       if (first_arg != NULL_TREE)

diff --git a/gcc/testsuite/g++.dg/inherit/virtual15.C b/gcc/testsuite/g++.dg/inherit/virtual15.C
new file mode 100644 (file)
index 0000000..ebd8e3a
--- /dev/null
+++ b/gcc/testsuite/g++.dg/inherit/virtual15.C
@@ -0,0 +1,18 @@
+// PR c++/100797
+// { dg-do run }
+
+bool ok = false;
+struct S1 { virtual ~S1() {} };
+struct S2 { virtual void f1() = 0; };
+struct S3: S1, S2 {
+    void f1() { f2(); }
+    virtual void f2() = 0;
+};
+struct S4: S3 {
+  void f2() { ok = true; }
+  using S2::f1;
+};
+int main() {
+  S4().f1();
+  if (!ok) __builtin_abort ();
+}

diff --git a/gcc/testsuite/g++.dg/inherit/virtual15a.C b/gcc/testsuite/g++.dg/inherit/virtual15a.C
new file mode 100644 (file)
index 0000000..6139385
--- /dev/null
+++ b/gcc/testsuite/g++.dg/inherit/virtual15a.C
@@ -0,0 +1,19 @@
+// PR c++/100797 plus diamond inheritance
+// { dg-do run }
+
+bool ok = false;
+struct S1 { virtual ~S1() {} };
+struct S2 { virtual void f1() = 0; };
+struct S3: S1, virtual S2 {
+    void f1() { f2(); }
+    virtual void f2() = 0;
+};
+struct SX: virtual S2 { };
+struct S4: SX, S3 {
+  void f2() { ok = true; }
+  using S2::f1;
+};
+int main() {
+  S4().f1();
+  if (!ok) __builtin_abort ();
+}