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* [gcc r12-1114] c++: 'this' adjustment for devirtualized call
@ 2021-05-28 12:58 Jason Merrill
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From: Jason Merrill @ 2021-05-28 12:58 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:f838e3ccf8d2849980e9d0f70aa60ecd2eb5772c
commit r12-1114-gf838e3ccf8d2849980e9d0f70aa60ecd2eb5772c
Author: Jason Merrill <jason@redhat.com>
Date: Thu May 27 23:54:52 2021 -0400
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:
---
gcc/cp/call.c | 22 ++++++++++++++++++----
gcc/testsuite/g++.dg/inherit/virtual15.C | 18 ++++++++++++++++++
gcc/testsuite/g++.dg/inherit/virtual15a.C | 19 +++++++++++++++++++
3 files changed, 55 insertions(+), 4 deletions(-)
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 3076fe67d5c..bf524b50bc4 100644
--- 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
index 00000000000..ebd8e3ad29b
--- /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
index 00000000000..6139385192d
--- /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 ();
+}
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