From fc2fb4fd547fb39d76237a3a1a50f5c4f3646936 Mon Sep 17 00:00:00 2001 From: Alexandre Oliva Date: Thu, 23 Jun 2022 23:20:48 -0300 Subject: [PATCH] Introduce -nostdlib++ option Using g++ to link without libstdc++, as in g++.dg/abi/pure-virtual1.C, is error prone, because there's no way to tell g++ to drop libstdc++ without also dropping libc and any other libraries that the target implicitly links in. This has often led to the need for manual adjustments to this testcase. I figured adding support for -nostdlib++, even though redundant, makes some sense. One could presumably use gcc rather than g++ for linking, for the same effect, but sometimes changing the link command is harder than adding an option, as in our testsuite. Since clang already had an option with this effect, we've adopted the same spelling. for gcc/ChangeLog * common.opt (nostdlib++): New. * doc/invoke.texi (-nostdlib++): Document it. for gcc/cp/ChangeLog * g++spec.cc (lang_specific_driver): Implement -nostdlib++. for gcc/testsuite/ChangeLog * g++.dg/abi/pure-virtual1.C: Use -nostdlib++. --- gcc/common.opt | 3 +++ gcc/cp/g++spec.cc | 1 + gcc/doc/invoke.texi | 6 +++++- gcc/testsuite/g++.dg/abi/pure-virtual1.C | 2 +- 4 files changed, 10 insertions(+), 2 deletions(-) diff --git a/gcc/common.opt b/gcc/common.opt index ed50f77848dd..e7a51e882bad 100644 --- a/gcc/common.opt +++ b/gcc/common.opt @@ -3467,6 +3467,9 @@ Driver nostdlib Driver +nostdlib++ +Driver + o Common Driver Joined Separate Var(asm_file_name) MissingArgError(missing filename after %qs) -o Place output into . diff --git a/gcc/cp/g++spec.cc b/gcc/cp/g++spec.cc index 8174d652776b..b63d8350ba11 100644 --- a/gcc/cp/g++spec.cc +++ b/gcc/cp/g++spec.cc @@ -159,6 +159,7 @@ lang_specific_driver (struct cl_decoded_option **in_decoded_options, switch (decoded_options[i].opt_index) { case OPT_nostdlib: + case OPT_nostdlib__: case OPT_nodefaultlibs: library = -1; break; diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 07a1bf40ad94..f794edd49e11 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -653,7 +653,7 @@ Objective-C and Objective-C++ Dialects}. @item Linker Options @xref{Link Options,,Options for Linking}. @gccoptlist{@var{object-file-name} -fuse-ld=@var{linker} -l@var{library} @gol --nostartfiles -nodefaultlibs -nolibc -nostdlib @gol +-nostartfiles -nodefaultlibs -nolibc -nostdlib -nostdlib++ @gol -e @var{entry} --entry=@var{entry} @gol -pie -pthread -r -rdynamic @gol -s -static -static-pie -static-libgcc -static-libstdc++ @gol @@ -16846,6 +16846,10 @@ library subroutines. constructors are called; @pxref{Collect2,,@code{collect2}, gccint, GNU Compiler Collection (GCC) Internals}.) +@item -nostdlib++ +@opindex nostdlib++ +Do not implicitly link with standard C++ libraries. + @item -e @var{entry} @itemx --entry=@var{entry} @opindex e diff --git a/gcc/testsuite/g++.dg/abi/pure-virtual1.C b/gcc/testsuite/g++.dg/abi/pure-virtual1.C index 538e2cb097a0..59eaf2256204 100644 --- a/gcc/testsuite/g++.dg/abi/pure-virtual1.C +++ b/gcc/testsuite/g++.dg/abi/pure-virtual1.C @@ -1,7 +1,7 @@ // Test that we don't need libsupc++ just for __cxa_pure_virtual. // { dg-do link } // { dg-require-weak } -// { dg-additional-options "-fno-rtti -nodefaultlibs -lc" } +// { dg-additional-options "-fno-rtti -nostdlib++" } // { dg-additional-options "-Wl,-undefined,dynamic_lookup" { target *-*-darwin* } } // { dg-xfail-if "AIX weak" { powerpc-ibm-aix* } } -- 2.47.2