| Message ID | 20200903203053.3411268-15-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add support for Clang LTO | expand |
On Thu, Sep 03, 2020 at 01:30:39PM -0700, Sami Tolvanen wrote: > With LTO, llvm-nm prints out symbols for each archive member > separately, which results in a lot of duplicate dependencies in the > .mod file when CONFIG_TRIM_UNUSED_SYMS is enabled. When a module > consists of several compilation units, the output can exceed the > default xargs command size limit and split the dependency list to > multiple lines, which results in used symbols getting trimmed. > > This change removes duplicate dependencies, which will reduce the > probability of this happening and makes .mod files smaller and > easier to read. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org>
diff --git a/scripts/Makefile.build b/scripts/Makefile.build index b8f1f0d65a73..3bb36b4b853c 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -286,7 +286,7 @@ endef # List module undefined symbols (or empty line if not enabled) ifdef CONFIG_TRIM_UNUSED_KSYMS -cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | xargs echo +cmd_undef_syms = $(NM) $< | sed -n 's/^ *U //p' | sort -u | xargs echo else cmd_undef_syms = echo endif
With LTO, llvm-nm prints out symbols for each archive member separately, which results in a lot of duplicate dependencies in the .mod file when CONFIG_TRIM_UNUSED_SYMS is enabled. When a module consists of several compilation units, the output can exceed the default xargs command size limit and split the dependency list to multiple lines, which results in used symbols getting trimmed. This change removes duplicate dependencies, which will reduce the probability of this happening and makes .mod files smaller and easier to read. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- scripts/Makefile.build | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)