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 -nolibstdc++, 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.
Regstrapped on x86_64-linux-gnu, also tested with a cross to
aarch64-rtems6. Ok to install?
for gcc/ChangeLog
* common.opt (nolibstdc++): New.
* doc/invoke.texi (-nolibstdc++): Document it.
for gcc/cp/ChangeLog
* g++spec.c (lang_specific_driver): Implement -nolibstdc++.
for gcc/testsuite/ChangeLog
* g++.dg/abi/pure-virtual1.C: Use -nolibstdc++.
---
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 32917aafcaec1..e00c6fc2fb098 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -3456,6 +3456,9 @@ Driver
nolibc
Driver
+nolibstdc++
+Driver
+
nostdlib
Driver
diff --git a/gcc/cp/g++spec.cc b/gcc/cp/g++spec.cc
index 8174d652776b1..539e6ca089d85 100644
--- a/gcc/cp/g++spec.cc
+++ b/gcc/cp/g++spec.cc
@@ -160,6 +160,7 @@ lang_specific_driver (struct cl_decoded_option
**in_decoded_options,
{
case OPT_nostdlib:
case OPT_nodefaultlibs:
+ case OPT_nolibstdc__:
library = -1;
break;
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 50f57877477bc..469b6d97e0dfa 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -652,7 +652,7 @@ 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 -nolibstdc++ -nostdlib @gol
-e @var{entry} --entry=@var{entry} @gol
-pie -pthread -r -rdynamic @gol
-s -static -static-pie -static-libgcc -static-libstdc++ @gol
@@ -16787,6 +16787,10 @@ absence of a C library is assumed, for example
@option{-lpthread} or
@option{-lm} in some configurations. This is intended for bare-board
targets when there is indeed no C library available.
+@item -nolibstdc++
+@opindex nolibstdc++
+Do not link with standard C++ libraries implicitly.
+
@item -nostdlib
@opindex nostdlib
Do not use the standard system startup files or libraries when linking.
diff --git a/gcc/testsuite/g++.dg/abi/pure-virtual1.C
b/gcc/testsuite/g++.dg/abi/pure-virtual1.C
index 538e2cb097a0d..889c33e4952f4 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 -nolibstdc++" }
// { dg-additional-options "-Wl,-undefined,dynamic_lookup" { target
*-*-darwin* } }
// { dg-xfail-if "AIX weak" { powerpc-ibm-aix* } }
--
Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/
Free Software Activist GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice
but very few check the facts. Ask me about <https://stallmansupport.org>
