From b1c9b3c3408c1ec8043f9b9e1a148f84bb7f3b25 Mon Sep 17 00:00:00 2001 From: Patrick Palka 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) : Don't print the "operator " prefix for __alignof__. : 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 0698e58a335..40e92229d8a 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 7d0e0d9c88a..9552cebe0d6 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 9fd30011288..5548e51d39d 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 8d0d2136831..553cc07e330 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 08106004c4d..7c3c17051ed 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 00000000000..a4d7f24a4d7 --- /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 + +template void f1(decltype(alignof(T))) { } +template void f2(decltype(alignof(T{}))) { } +template void f3(decltype(__alignof__(T))) { } +template void f4(decltype(__alignof__(T{}))) { } + +template void f1(std::size_t); +template void f2(std::size_t); +template void f3(std::size_t); +template void f4(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 00000000000..a9368e21b0b --- /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 aede23fbf6b..a9f8e759ff5 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 0850db3d6dd..4ad9da82f2c 100644 --- a/libiberty/testsuite/demangle-expected +++ b/libiberty/testsuite/demangle-expected @@ -1469,3 +1469,10 @@ f(A) # PR 96143 _Z2F2IZ1FvEUlvE_EN1AIT_E1XES2_ A::X F2(F()::{lambda()#1}) + +# PR 88115 +_Z1fIiEvDTv111__alignof__T_E +void f(decltype (__alignof__(int))) + +_Z1fIiEvDTv111__alignof__tlT_EE +void f(decltype (__alignof__(int{}))) -- 2.30.2