The following prototype patch re-uses cc1-checksum.c from the
previous stage when compiling stage-final. This eventually
allows to compare cc1 from the last two stages to fix the
lack of a true comparison when doing LTO bootstrap (it
compiles LTO bytecode from the compile-stage there, not the
final optimization result).
Bootstrapped on x86_64-unknown-linux-gnu.
When stripping gcc/cc1 and prev-gcc/cc1 after the bootstrap
they now compare identical (with LTO bootstrap it should
not require stripping as that doesn't do a bootstrap-debug AFAIK).
Is sth like this acceptable? (consider it also done for cp/Make-lang.in)
In theory we can compare all stage1 languages but I guess comparing
the required ones for a LTO bootstrap, cc1, cc1plus and lto1 would
be sufficient (or even just comparing one binary in which case
comparing lto1 would not require any patches).
This also gets rid of the annoying warning that cc1-checksum.o
differs (obviously).
Thanks,
Richard.
2016-04-28 Richard Biener <rguent...@suse.de>
c/
* Make-lang.in (cc1-checksum.c): For stage-final re-use
the checksum from the previous stage.
Index: gcc/c/Make-lang.in
===================================================================
--- gcc/c/Make-lang.in (revision 235499)
+++ gcc/c/Make-lang.in (working copy)
@@ -63,9 +63,14 @@ c-warn = $(STRICT_WARN)
# compute checksum over all object files and the options
cc1-checksum.c : build/genchecksum$(build_exeext) checksum-options \
$(C_OBJS) $(BACKEND) $(LIBDEPS)
- build/genchecksum$(build_exeext) $(C_OBJS) $(BACKEND) $(LIBDEPS) \
+ if [ -f ../stage_final ] \
+ && cmp -s ../stage_current ../stage_final; then \
+ cp ../prev-gcc/cc1-checksum.c cc1-checksum.c; \
+ else \
+ build/genchecksum$(build_exeext) $(C_OBJS) $(BACKEND) $(LIBDEPS) \
checksum-options > cc1-checksum.c.tmp && \
- $(srcdir)/../move-if-change cc1-checksum.c.tmp cc1-checksum.c
+ $(srcdir)/../move-if-change cc1-checksum.c.tmp cc1-checksum.c; \
+ fi
cc1$(exeext): $(C_OBJS) cc1-checksum.o $(BACKEND) $(LIBDEPS)
+$(LLINKER) $(ALL_LINKERFLAGS) $(LDFLAGS) -o $@ $(C_OBJS) \
