On Tue, Jan 19, 2021 at 05:38:20PM -0500, Marek Polacek via Gcc-patches wrote:
> On Tue, Jan 19, 2021 at 03:47:47PM -0500, Jason Merrill via Gcc-patches wrote:
> > On 1/13/21 6:39 PM, Marek Polacek wrote:
> > > r11-6301 added some asserts in mangle.c, and now we trip over one of
> > > them. In particular, it's the one asserting that we didn't get
> > > IDENTIFIER_ANY_OP_P when mangling an expression with a dependent name.
> > >
> > > As this testcase shows, it's possible to get that, so turn the assert
> > > into an if and write "on". That changes the mangling in the following
> > > way:
> > >
> > > With this patch:
> > >
> > > $ c++filt _ZN1i1hIJ1adS1_EEEDTcldtdefpTonclspcvT__EEEDpS2_
> > > decltype (((*this).(operator()))((a)(), (double)(), (a)())) i::h<a,
> > > double, a>(a, double, a)
> > >
> > > G++10:
> > > $ c++filt _ZN1i1hIJ1adS1_EEEDTcldtdefpTclspcvT__EEEDpS2_
> > > decltype (((*this).(operator()))((a)(), (double)(), (a)())) i::h<a,
> > > double, a>(a, double, a)
> > >
> > > clang++/icc:
> > > $ c++filt _ZN1i1hIJ1adS1_EEEDTclonclspcvT__EEEDpS2_
> > > decltype ((operator())((a)(), (double)(), (a)())) i::h<a, double, a>(a,
> > > double, a)
> > >
> > > I'm not sure why we differ in the "(*this)." part
> >
> > Is there a PR for that?
>
> I just opened 98756, because I didn't find any. I can investigate where that
> (*this) comes from, though it's not readily clear to me if this is a bug or
> not.
>
> > > but at least the
> > > suffix "onclspcvT__EEEDpS2_" is the same for all three compilers. So
> > > I hope the following fix makes sense.
> > >
> > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> > >
> > > gcc/cp/ChangeLog:
> > >
> > > PR c++/98545
> > > * mangle.c (write_expression): When the expression is a dependent name
> > > and an operator name, write "on" before writing its name.
> > >
> > > gcc/testsuite/ChangeLog:
> > >
> > > PR c++/98545
> > > * g++.dg/abi/mangle76.C: New test.
> > > ---
> > > gcc/cp/mangle.c | 3 ++-
> > > gcc/testsuite/g++.dg/abi/mangle76.C | 39 +++++++++++++++++++++++++++++
> > > 2 files changed, 41 insertions(+), 1 deletion(-)
> > > create mode 100644 gcc/testsuite/g++.dg/abi/mangle76.C
> > >
> > > diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
> > > index 11eb8962d28..bb3c4b76d33 100644
> > > --- a/gcc/cp/mangle.c
> > > +++ b/gcc/cp/mangle.c
> > > @@ -3349,7 +3349,8 @@ write_expression (tree expr)
> > > else if (dependent_name (expr))
> > > {
> > > tree name = dependent_name (expr);
> > > - gcc_assert (!IDENTIFIER_ANY_OP_P (name));
> > > + if (IDENTIFIER_ANY_OP_P (name))
> > > + write_string ("on");
> >
> > Any mangling change needs to handle different -fabi-versions; see the
> > similar code in write_member_name.
>
> Ah, I only looked at the unguarded IDENTIFIER_ANY_OP_P checks. But now
> I have a possibly stupid question: what version should I check? We have
> Version 11 for which the manual already says "corrects the mangling of
> sizeof... expressions and *operator names*", so perhaps I could tag along
> and check abi_version_at_least (11). Or should I check Version 15 and
> update the manual?
The latter seems to be true, therefore a new patch is attached.
> > And why doesn't this go through write_member_name?
>
> We go through write_member_name:
>
> #0 fancy_abort (file=0x2b98ef8 "/home/mpolacek/src/gcc/gcc/cp/mangle.c",
> line=3352,
> function=0x2b99751 "write_expression") at
> /home/mpolacek/src/gcc/gcc/diagnostic.c:1884
> #1 0x0000000000bee91b in write_expression (expr=<overload 0x7fffea02eb20>)
> at /home/mpolacek/src/gcc/gcc/cp/mangle.c:3352
> #2 0x0000000000beb3e2 in write_member_name (member=<baselink 0x7fffea043ae0>)
> at /home/mpolacek/src/gcc/gcc/cp/mangle.c:2892
> #3 0x0000000000beee70 in write_expression (expr=<component_ref
> 0x7fffea043b40>)
> at /home/mpolacek/src/gcc/gcc/cp/mangle.c:3405
> #4 0x0000000000bef1be in write_expression (expr=<call_expr 0x7fffe9ede118>)
> at /home/mpolacek/src/gcc/gcc/cp/mangle.c:3455
> #5 0x0000000000be858a in write_type (type=<decltype_type 0x7fffea04b348>)
> at /home/mpolacek/src/gcc/gcc/cp/mangle.c:2343
>
> so in write_member_name MEMBER is a BASELINK so we don't enter the
> identifier_p block.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
r11-6301 added some asserts in mangle.c, and now we trip over one of
them. In particular, it's the one asserting that we didn't get
IDENTIFIER_ANY_OP_P when mangling an expression with a dependent name.
As this testcase shows, it's possible to get that, so turn the assert
into an if and write "on". That changes the mangling in the following
way:
With this patch:
$ c++filt _ZN1i1hIJ1adS1_EEEDTcldtdefpTonclspcvT__EEEDpS2_
decltype (((*this).(operator()))((a)(), (double)(), (a)())) i::h<a, double,
a>(a, double, a)
G++10:
$ c++filt _ZN1i1hIJ1adS1_EEEDTcldtdefpTclspcvT__EEEDpS2_
decltype (((*this).(operator()))((a)(), (double)(), (a)())) i::h<a, double,
a>(a, double, a)
clang++/icc:
$ c++filt _ZN1i1hIJ1adS1_EEEDTclonclspcvT__EEEDpS2_
decltype ((operator())((a)(), (double)(), (a)())) i::h<a, double, a>(a, double,
a)
This is now tracked in PR98756.
gcc/cp/ChangeLog:
PR c++/98545
* mangle.c (write_expression): When the expression is a dependent name
and an operator name, write "on" before writing its name.
gcc/ChangeLog:
PR c++/98545
* doc/invoke.texi: Update C++ ABI Version 15 description.
gcc/testsuite/ChangeLog:
PR c++/98545
* g++.dg/abi/mangle76.C: New test.
---
gcc/cp/mangle.c | 7 ++++-
gcc/doc/invoke.texi | 3 ++-
gcc/testsuite/g++.dg/abi/mangle76.C | 40 +++++++++++++++++++++++++++++
3 files changed, 48 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/abi/mangle76.C
diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 11eb8962d28..9b358bbc5a1 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -3349,7 +3349,12 @@ write_expression (tree expr)
else if (dependent_name (expr))
{
tree name = dependent_name (expr);
- gcc_assert (!IDENTIFIER_ANY_OP_P (name));
+ if (abi_version_at_least (15) && IDENTIFIER_ANY_OP_P (name))
+ {
+ write_string ("on");
+ if (abi_warn_or_compat_version_crosses (15))
+ G.need_abi_warning = 1;
+ }
write_unqualified_id (name);
}
else
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 5f4a06625eb..99d25462e48 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -2837,7 +2837,8 @@ Version 14, which first appeared in G++ 10, corrects the
mangling of
the nullptr expression.
Version 15, which first appeared in G++ 11, changes the mangling of
-@code{__alignof__} to be distinct from that of @code{alignof}.
+@code{__alignof__} to be distinct from that of @code{alignof}, and
+dependent operator names.
See also @option{-Wabi}.
diff --git a/gcc/testsuite/g++.dg/abi/mangle76.C
b/gcc/testsuite/g++.dg/abi/mangle76.C
new file mode 100644
index 00000000000..fe326e6c689
--- /dev/null
+++ b/gcc/testsuite/g++.dg/abi/mangle76.C
@@ -0,0 +1,40 @@
+// PR c++/98545
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wabi=14" }
+
+class a {
+public:
+ a();
+ template <typename b> a(b);
+};
+template <class = double> using c = a;
+class f {
+protected:
+ template <class d, class e> void operator()(d, double, e);
+};
+class i : f {
+public:
+ template <class... g>
+ [[gnu::used]] auto h(g...) -> decltype(operator()(g()...)) {} // {
dg-warning "mangled name" }
+// { dg-final { scan-assembler
"_ZN1i1hIJ1adS1_EEEDTcldtdefpTonclspcvT__EEEDpS2_" } }
+};
+template <class> class C {
+public:
+ template <class j> C(j);
+ i k() const;
+ int operator()() {
+ int l = 10;
+ c<> m, n;
+ operator()(m, l, n);
+ return 0;
+ }
+ int operator()(c<> &, c<> const &, c<> const &) const;
+ template <class d, class e> void k(d m, double gamma, e o) const {
+ k().h(m, gamma, o);
+ }
+};
+template <class r> int C<r>::operator()(c<> &, c<> const &, c<> const &) const
{
+ [&](c<> m, double gamma, c<> o) { k(m, gamma, o); };
+ return 0;
+}
+c<> p = C<double>(p)();
base-commit: 0fb7aa205afebe178c06683037ccd4c41104337a
--
2.29.2
