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c++: 'this' adjustment for devirtualized call

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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.
This commit is contained in:
Jason Merrill 2021-05-27 23:54:52 -04:00
parent 359c0a86e2
commit f838e3ccf8
3 changed files with 55 additions and 4 deletions
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22
gcc/cp/call.c
View file

@ -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)

18
gcc/testsuite/g++.dg/inherit/virtual15.C Normal file
View file

@ -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 ();
}

19
gcc/testsuite/g++.dg/inherit/virtual15a.C Normal file
View file

@ -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 ();
}