Summary:
lld discards .gnu.linonce.* sections work around a bug in glibc.
https://sourceware.org/bugzilla/show_bug.cgi?id=20543
Unfortunately, the Linux kernel uses a section named
.gnu.linkonce.this_module to store infomation about kernel modules. The
kernel reads data from this section when loading kernel modules, and
errors if it fails to find this section. The current behavior of lld
discards this section when kernel modules are linked, so kernel modules
linked with lld are unloadable by the linux kernel.
The Linux kernel should use a comdat section instead of .gnu.linkonce.
The minimum version of binutils supported by the kernel supports comdat
sections. The kernel is also not relying on the old linkonce behavior;
it seems to have chosen a name that contains a deprecated GNU feature.
Changing the section name now in the kernel would require all kernel
modules to be recompiled to make use of the new section name. Instead,
rather than discarding .gnu.linkonce.*, let's discard the more specific
section name to continue working around the glibc issue while supporting
linking Linux kernel modules.
Link: https://github.com/ClangBuiltLinux/linux/issues/329
Reviewers: pcc, espindola
Reviewed By: pcc
Subscribers: nathanchance, emaste, arichardson, void, srhines
Differential Revision: https://reviews.llvm.org/D57294
llvm-svn: 352302
If building lld without x86 support, tests that require that support should
be treated as unsupported, not errors.
Tested using:
1. cmake '-DLLVM_TARGETS_TO_BUILD=AArch64;X86'
make check-lld
=>
Expected Passes : 1406
Unsupported Tests : 287
2. cmake '-DLLVM_TARGETS_TO_BUILD=AArch64'
make check-lld
=>
Expected Passes : 410
Unsupported Tests : 1283
Patch by Joel Jones
Differential Revision: https://reviews.llvm.org/D47748
llvm-svn: 334095
The linkonce feature is a sort of proto-comdat. As far as I am aware no
compiler produces linkonce sections anymore, but some glibc i386 object
files contain definitions of symbol "__x86.get_pc_thunk.bx" in linkonce
sections. Drop those sections to avoid duplicate symbol errors.
This is glibc PR20543, we should remove this hack once that has been
fixed for a while.
Fixes PR31215.
Differential Revision: https://reviews.llvm.org/D28430
llvm-svn: 291474
Nick Desaulniers