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| author | Alexandre Oliva <aoliva@redhat.com> | 2017-11-15 03:11:37 +0000 |
|---|---|---|
| committer | Alexandre Oliva <aoliva@gcc.gnu.org> | 2017-11-15 03:11:37 +0000 |
| commit | 3267bd36aaf32ac4c88e5a4618067d9141fbfac7 (patch) | |
| tree | 5d4271af7bdbe2924a3d00fddbbe6990a298ced7 /config | |
| parent | 3ca0dc603213b2ad5ffbcf1a443a102bef96053a (diff) | |
Use compare-debug for bootstrap-debug-lean to ignore != DW_AT_producer
Unlike bootstrap-debug, bootstrap-debug-lean used to pass compare using
the traditional compare command, because it compiled both stage2 and
stage3 with options that used to generate identical output
(-fcompare-debug= in stage2 vs -fcompare-debug in stage3).
Since we started adding relevant command-line flags to DW_AT_producer,
this is no longer the case, and stages 2 and 3 object files that differ
in nothing but the DW_AT_producer strings.
-fcompare-debug is short for -fcompare-debug=-gtoggle, so stage3
compiles twice, once with the normal options, once with toggled -g, to
then compare the temporary final dumps. When enabled, both compilations
get from the driver an additional -frandom-seed flag (if none is given
explicitly).
-fcompare-debug= is short for -fno-compare-debug, disabling the second
compilation.
The difference between the DW_AT_producer lines are the different
-fcompare-debug flags, and the presence of the -frandom-seed flag in the
stage3 compilation.
It is easy and sensible enough to filter the -fcompare-debug flags out
of the DW_AT_producer string. This option should never affect the
compilation output, it just determines whether or not to perform an
additional compilation that should produce the same executable output.
However, dropping -frandom-seed is not quite correct, in that it might
have other consequences on the compilation. So, it makes little sense
to make the effort to drop it when it's implicit; for those comparing
compiler output differences, it might even hint at what causes, and
could fix, difficult to explain differences, namely, explicitly
supplying -frandom-seed options.
They don't seem to matter for compiler bootstraps, though, at least
for now, so we can safely refrain from issuing -frandom-seed (or maybe
we already issue it where needed :-), and then, for
bootstrap-debug-lean, use the compare-debug script, that strips out
debug information before comparing the object files.
for config/ChangeLog
* bootstrap-debug-lean.mk (do-compare): Use the
contrib/compare-debug script.
for gcc/ChangeLog
* dwarf2out.c (gen_producer_string): Discard
OPT_fcompare_debug.
From-SVN: r254750
Diffstat (limited to 'config')
| -rw-r--r-- | config/ChangeLog | 5 | ||||
| -rw-r--r-- | config/bootstrap-debug-lean.mk | 1 |
2 files changed, 6 insertions, 0 deletions
diff --git a/config/ChangeLog b/config/ChangeLog index 2e3ead0a26b..90e1af4779d 100644 --- a/config/ChangeLog +++ b/config/ChangeLog @@ -1,3 +1,8 @@ +2017-11-15 Alexandre Oliva <aoliva@redhat.com> + + * bootstrap-debug-lean.mk (do-compare): Use the + contrib/compare-debug script. + 2017-10-24 H.J. Lu <hongjiu.lu@intel.com> * bootstrap-cet.mk: New file. diff --git a/config/bootstrap-debug-lean.mk b/config/bootstrap-debug-lean.mk index e215280b09f..5f2db80687f 100644 --- a/config/bootstrap-debug-lean.mk +++ b/config/bootstrap-debug-lean.mk @@ -9,3 +9,4 @@ STAGE2_CFLAGS += -fcompare-debug= STAGE3_CFLAGS += -fcompare-debug +do-compare = $(SHELL) $(srcdir)/contrib/compare-debug $$f1 $$f2 |