gcc/SOURCES/gcc8-pr100797.patch

138 lines
4.5 KiB
Diff
Raw Normal View History

2021-06-09 04:17:15 +00:00
commit ebfe8b28d40746ff33724bd5b9ade2552e619213
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.
This backport also incorporates a bit of the r11-1638 reorganization.
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.
* g++.dg/inherit/virtual15a.C: New test.
--- gcc/cp/call.c
+++ gcc/cp/call.c
@@ -8309,19 +8309,6 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
|| CLASSTYPE_FINAL (TYPE_METHOD_BASETYPE (TREE_TYPE (fn))))
flags |= LOOKUP_NONVIRTUAL;
- /* 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))
- {
- tree binfo = cand->conversion_path;
- if (BINFO_TYPE (binfo) != DECL_CONTEXT (fn))
- binfo = lookup_base (binfo, DECL_CONTEXT (fn), ba_unique,
- NULL, complain);
- fn = lookup_vfn_in_binfo (DECL_VINDEX (fn), binfo);
- flags |= LOOKUP_NONVIRTUAL;
- }
-
/* [class.mfct.nonstatic]: If a nonstatic member function of a class
X is called for an object that is not of type X, or of a type
derived from X, the behavior is undefined.
@@ -8331,10 +8318,6 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
gcc_assert (TYPE_PTR_P (parmtype));
/* Convert to the base in which the function was declared. */
gcc_assert (cand->conversion_path != NULL_TREE);
- converted_arg = build_base_path (PLUS_EXPR,
- arg,
- cand->conversion_path,
- 1, complain);
/* Check that the base class is accessible. */
if (!accessible_base_p (TREE_TYPE (argtype),
BINFO_TYPE (cand->conversion_path), true))
@@ -8349,10 +8332,33 @@ build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
/* If fn was found by a using declaration, the conversion path
will be to the derived class, not the base declaring fn. We
must convert from derived to base. */
- base_binfo = lookup_base (TREE_TYPE (TREE_TYPE (converted_arg)),
+ base_binfo = lookup_base (cand->conversion_path,
TREE_TYPE (parmtype), ba_unique,
NULL, complain);
- converted_arg = build_base_path (PLUS_EXPR, converted_arg,
+
+ /* 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))
+ {
+ 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;
+ }
+ }
+
+ converted_arg = build_base_path (PLUS_EXPR, arg,
base_binfo, 1, complain);
argarray[j++] = converted_arg;
--- /dev/null
+++ 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 ();
+}
--- /dev/null
+++ 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 ();
+}