From b1c9b3c3408c1ec8043f9b9e1a148f84bb7f3b25 Mon Sep 17 00:00:00 2001
From: Patrick Palka <ppalka@redhat.com>
Date: Wed, 11 Nov 2020 15:11:23 -0500
Subject: [PATCH] c++: Change the mangling of __alignof__ [PR88115]
This patch changes the mangling of __alignof__ to v111__alignof__,
making its mangling distinct from that of alignof(type) and
alignof(expr).
How we mangle ALIGNOF_EXPR now depends on its ALIGNOF_EXPR_STD_P flag,
which after the previous patch gets consistently set for alignof(type)
as well as alignof(expr).
gcc/c-family/ChangeLog:
PR c++/88115
* c-opts.c (c_common_post_options): Update latest_abi_version.
gcc/ChangeLog:
PR c++/88115
* common.opt (-fabi-version): Document =15.
* doc/invoke.texi (C++ Dialect Options): Likewise.
gcc/cp/ChangeLog:
PR c++/88115
* mangle.c (write_expression): Mangle __alignof_ differently
from alignof when the ABI version is at least 15.
libiberty/ChangeLog:
PR c++/88115
* cp-demangle.c (d_print_comp_inner)
<case DEMANGLE_COMPONENT_EXTENDED_OPERATOR>: Don't print the
"operator " prefix for __alignof__.
<case DEMANGLE_COMPONENT_UNARY>: Always print parens around the
operand of __alignof__.
* testsuite/demangle-expected: Test demangling for __alignof__.
gcc/testsuite/ChangeLog:
PR c++/88115
* g++.dg/abi/macro0.C: Adjust.
* g++.dg/cpp0x/alignof7.C: New test.
* g++.dg/cpp0x/alignof8.C: New test.
---
gcc/c-family/c-opts.c | 2 +-
gcc/common.opt | 4 ++++
gcc/cp/mangle.c | 27 +++++++++++++++++++++++----
gcc/doc/invoke.texi | 3 +++
gcc/testsuite/g++.dg/abi/macro0.C | 2 +-
gcc/testsuite/g++.dg/cpp0x/alignof7.C | 22 ++++++++++++++++++++++
gcc/testsuite/g++.dg/cpp0x/alignof8.C | 13 +++++++++++++
libiberty/cp-demangle.c | 25 ++++++++++++++++++++-----
libiberty/testsuite/demangle-expected | 7 +++++++
9 files changed, 94 insertions(+), 11 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/alignof7.C
create mode 100644 gcc/testsuite/g++.dg/cpp0x/alignof8.C
diff --git a/gcc/c-family/c-opts.c b/gcc/c-family/c-opts.c
index 0698e58a335d..40e92229d8ac 100644
--- a/gcc/c-family/c-opts.c
+++ b/gcc/c-family/c-opts.c
@@ -945,7 +945,7 @@ c_common_post_options (const char **pfilename)
/* Change flag_abi_version to be the actual current ABI level, for the
benefit of c_cpp_builtins, and to make comparison simpler. */
- const int latest_abi_version = 14;
+ const int latest_abi_version = 15;
/* Generate compatibility aliases for ABI v11 (7.1) by default. */
const int abi_compat_default = 11;
diff --git a/gcc/common.opt b/gcc/common.opt
index 7d0e0d9c88a8..9552cebe0d6c 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -960,9 +960,13 @@ Driver Undocumented
; 13: Fixes the accidental change in 12 to the calling convention for classes
; with deleted copy constructor and trivial move constructor.
; Default in G++ 8.2.
+;
; 14: Corrects the mangling of nullptr expression.
; Default in G++ 10.
;
+; 15: Changes the mangling of __alignof__ to be distinct from that of alignof.
+; Default in G++ 11.
+;
; Additional positive integers will be assigned as new versions of
; the ABI become the default version of the ABI.
fabi-version=
diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 9fd300112886..5548e51d39d1 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -3049,11 +3049,30 @@ write_expression (tree expr)
else
goto normal_expr;
}
- else if (TREE_CODE (expr) == ALIGNOF_EXPR
- && TYPE_P (TREE_OPERAND (expr, 0)))
+ else if (TREE_CODE (expr) == ALIGNOF_EXPR)
{
- write_string ("at");
- write_type (TREE_OPERAND (expr, 0));
+ if (!ALIGNOF_EXPR_STD_P (expr))
+ {
+ if (abi_warn_or_compat_version_crosses (15))
+ G.need_abi_warning = true;
+ if (abi_version_at_least (15))
+ {
+ /* We used to mangle __alignof__ like alignof. */
+ write_string ("v111__alignof__");
+ if (TYPE_P (TREE_OPERAND (expr, 0)))
+ write_type (TREE_OPERAND (expr, 0));
+ else
+ write_expression (TREE_OPERAND (expr, 0));
+ return;
+ }
+ }
+ if (TYPE_P (TREE_OPERAND (expr, 0)))
+ {
+ write_string ("at");
+ write_type (TREE_OPERAND (expr, 0));
+ }
+ else
+ goto normal_expr;
}
else if (code == SCOPE_REF
|| code == BASELINK)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 8d0d2136831a..553cc07e3306 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -2807,6 +2807,9 @@ change in version 12.
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}.
+
See also @option{-Wabi}.
@item -fabi-compat-version=@var{n}
diff --git a/gcc/testsuite/g++.dg/abi/macro0.C b/gcc/testsuite/g++.dg/abi/macro0.C
index 08106004c4d0..7c3c17051ed6 100644
--- a/gcc/testsuite/g++.dg/abi/macro0.C
+++ b/gcc/testsuite/g++.dg/abi/macro0.C
@@ -1,6 +1,6 @@
// This testcase will need to be kept in sync with c_common_post_options.
// { dg-options "-fabi-version=0" }
-#if __GXX_ABI_VERSION != 1014
+#if __GXX_ABI_VERSION != 1015
#error "Incorrect value of __GXX_ABI_VERSION"
#endif
diff --git a/gcc/testsuite/g++.dg/cpp0x/alignof7.C b/gcc/testsuite/g++.dg/cpp0x/alignof7.C
new file mode 100644
index 000000000000..a4d7f24a4d75
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/alignof7.C
@@ -0,0 +1,22 @@
+// PR c++/88115
+// { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wno-pedantic" }
+
+// Verify we mangle __alignof__ differently from alignof.
+
+#include <cstddef>
+
+template <class T> void f1(decltype(alignof(T))) { }
+template <class T> void f2(decltype(alignof(T{}))) { }
+template <class T> void f3(decltype(__alignof__(T))) { }
+template <class T> void f4(decltype(__alignof__(T{}))) { }
+
+template void f1<int>(std::size_t);
+template void f2<int>(std::size_t);
+template void f3<int>(std::size_t);
+template void f4<int>(std::size_t);
+
+// { dg-final { scan-assembler "_Z2f1IiEvDTatT_E" } }
+// { dg-final { scan-assembler "_Z2f2IiEvDTaztlT_EE" } }
+// { dg-final { scan-assembler "_Z2f3IiEvDTv111__alignof__T_E" } }
+// { dg-final { scan-assembler "_Z2f4IiEvDTv111__alignof__tlT_EE" } }
diff --git a/gcc/testsuite/g++.dg/cpp0x/alignof8.C b/gcc/testsuite/g++.dg/cpp0x/alignof8.C
new file mode 100644
index 000000000000..a9368e21b0b8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/alignof8.C
@@ -0,0 +1,13 @@
+// PR c++/88115
+// { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wno-pedantic -fabi-version=14 -Wabi" }
+
+#include "alignof7.C"
+
+// { dg-warning "changes between" "" { target *-*-* } 11 }
+// { dg-warning "changes between" "" { target *-*-* } 12 }
+
+// { dg-final { scan-assembler "_Z2f1IiEvDTatT_E" } }
+// { dg-final { scan-assembler "_Z2f2IiEvDTaztlT_EE" } }
+// { dg-final { scan-assembler "_Z2f3IiEvDTatT_E" } }
+// { dg-final { scan-assembler "_Z2f4IiEvDTaztlT_EE" } }
diff --git a/libiberty/cp-demangle.c b/libiberty/cp-demangle.c
index aede23fbf6b6..a9f8e759ff53 100644
--- a/libiberty/cp-demangle.c
+++ b/libiberty/cp-demangle.c
@@ -5458,9 +5458,18 @@ d_print_comp_inner (struct d_print_info *dpi, int options,
}
case DEMANGLE_COMPONENT_EXTENDED_OPERATOR:
- d_append_string (dpi, "operator ");
- d_print_comp (dpi, options, dc->u.s_extended_operator.name);
- return;
+ {
+ struct demangle_component *name = dc->u.s_extended_operator.name;
+ if (name->type == DEMANGLE_COMPONENT_NAME
+ && !strncmp (name->u.s_name.s, "__alignof__", name->u.s_name.len))
+ d_print_comp (dpi, options, dc->u.s_extended_operator.name);
+ else
+ {
+ d_append_string (dpi, "operator ");
+ d_print_comp (dpi, options, dc->u.s_extended_operator.name);
+ }
+ return;
+ }
case DEMANGLE_COMPONENT_CONVERSION:
d_append_string (dpi, "operator ");
@@ -5525,8 +5534,14 @@ d_print_comp_inner (struct d_print_info *dpi, int options,
if (code && !strcmp (code, "gs"))
/* Avoid parens after '::'. */
d_print_comp (dpi, options, operand);
- else if (code && !strcmp (code, "st"))
- /* Always print parens for sizeof (type). */
+ else if ((code && !strcmp (code, "st"))
+ || (op->type == DEMANGLE_COMPONENT_EXTENDED_OPERATOR
+ && (op->u.s_extended_operator.name->type
+ == DEMANGLE_COMPONENT_NAME)
+ && !strncmp (op->u.s_extended_operator.name->u.s_name.s,
+ "__alignof__",
+ op->u.s_extended_operator.name->u.s_name.len)))
+ /* Always print parens for sizeof (type) and __alignof__. */
{
d_append_char (dpi, '(');
d_print_comp (dpi, options, operand);
diff --git a/libiberty/testsuite/demangle-expected b/libiberty/testsuite/demangle-expected
index 0850db3d6dd4..4ad9da82f2c7 100644
--- a/libiberty/testsuite/demangle-expected
+++ b/libiberty/testsuite/demangle-expected
@@ -1469,3 +1469,10 @@ f(A<X{.a.b[3 ... 4]=(1)}>)
# PR 96143
_Z2F2IZ1FvEUlvE_EN1AIT_E1XES2_
A<F()::{lambda()#1}>::X F2<F()::{lambda()#1}>(F()::{lambda()#1})
+
+# PR 88115
+_Z1fIiEvDTv111__alignof__T_E
+void f<int>(decltype (__alignof__(int)))
+
+_Z1fIiEvDTv111__alignof__tlT_EE
+void f<int>(decltype (__alignof__(int{})))
--
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