RFR (S): JDK-8142909 Integration of minor fixes from the build-infra project

David Holmes david.holmes at oracle.com
Tue Nov 17 01:57:17 UTC 2015 

On 16/11/2015 10:14 PM, Erik Joelsson wrote:
> On 2015-11-16 12:11, David Holmes wrote:
>> On 16/11/2015 6:22 PM, Erik Joelsson wrote:
>>> On 2015-11-16 03:10, David Holmes wrote:
>>>> Hi Magnus,
>>>>
>>>> On 13/11/2015 9:33 PM, Magnus Ihse Bursie wrote:
>>>>> On 2015-11-13 09:13, Erik Joelsson wrote:
>>>>>> Hello,
>>>>>>
>>>>>> make/bsd/makefiles/amd64.make:
>>>>>> make/bsd/makefiles/gcc.make:
>>>>>> Perhaps the order of "$(OPT_CFLAGS/NOOPT) $(OPT_CFLAGS/$(BUILDARCH))"
>>>>>> should be reversed to guarantee that NOOPT is the one used in case
>>>>>> BUILDARCH contains something that conflicts? The solaris file does it
>>>>>> this way.
>>>>> You know you wrote that code originally? ;-)
>>>>>
>>>>> Yeah, I agree, it's more reasonable. Updated webrev:
>>>>> http://cr.openjdk.java.net/~ihse/JDK-8142909-hotspot-build-infra-integration/webrev.02
>>>>>
>>>>>
>>>>
>>>> I don't like this particular change as it is too generic. It gives the
>>>> appearance of being apply to apply whatever the BUILDARCH specific
>>>> optflags are, which makes no sense if the whole point here is to not
>>>> optimize these files. If all this is intended to do is include -g then
>>>> I think that should be done explicitly.
>>>>
>>> The -g flag is added to OPT_CFLAGS/$(BUILDARCH) and I can only assume
>>> the intention was to have it added to all compilation command lines.
>>> However, the OPT_CFLAGS/<filename> variable overrides
>>> CFLAGS/$(BUILDARCH), effectively removing the -g flag from the files
>>> where we explicitly change the optimization level. The patch intends to
>>> make sure -g is used on those files too.
>>
>> I understand that, but it is far from obvious that OPT_FLAGS/BUILDARCH
>> means -g (why???), or that putting other things in that variable might
>> break files that should not be optimized.
>>
>>> A cleaner solution would be to not have -g be part of the OPT flags at
>>> all but its own set of DEBUG_CFLAGS.
>>
>> I thought -g was in the DEBUG_CFLAGS ?? Or maybe it used to be. Anyway
>> if all we are interested in is adding -g then I agree it should have
>> its own variable.
>>
> I looked some more at this. There is a DEBUG_CFLAGS, FASTDEBUG_CFLAGS
> and OPT_CFLAGS. These get picked depending on the debug level of the
> build. For example in product.make, $(OPT_CFLAGS/BYFILE) gets added to
> CFLAGS.
>
> I can't really see a better way of making sure the -g does not fall off
> for some files than what is proposed here. At least not without
> completely reworking the flags handling in the current hotspot
> makefiles, something I'm very uninterested in doing.

In the -g case what we are handling is the addition of -g to product 
builds (it is already on fastdebug, debug) when 
ENABLE_FULL_DEBUG_SYMBOLS is selected, on a subset of architectures. As 
a convenience we define it thus (BSD version):

OPT_CFLAGS/ia64 = -g
OPT_CFLAGS/amd64 = -g
OPT_CFLAGS/arm = -g
OPT_CFLAGS/ppc = -g
OPT_CFLAGS += $(OPT_CFLAGS/$(BUILDARCH))

so $(OPT_CFLAGS/$(BUILDARCH)) happens to contain -g. I would be happy if 
the above were changed to:

FDS_CFLAGS/ia64 = -g
FDS_CFLAGS/amd64 = -g
FDS_CFLAGS/arm = -g
FDS_CFLAGS/ppc = -g
OPT_CFLAGS += $(FDS_CFLAGS/$(BUILDARCH))

and then you could use $(FDS_CFLAGS/$(BUILDARCH) on the "by-file" 
definitions, where it would be much clearer what kind of flag is 
actually being applied. However this needs to be done everywhere, and I 
don't see this fix attempting to do that. We set OPT_CFLAGS/<filename> 
in numerous places (open and closed) to regain control over the "opt" 
flags applied to that file. Sometimes we use predefined opt flags, like 
NOOPT or SPEED, and sometimes we don't eg:

linux/makefiles/amd64.make

OPT_CFLAGS/compactingPermGenGen.o = -O1

This would need to be applied to every occurrence of the "byfile" 
definitions in all the makefiles. Or else ascertained on a case-by-case 
basis that we don't want -g for a specific file.

Further, on architectures where $(FDS_CFLAGS/$(BUILDARCH) is not set you 
still have to somehow handle the rest of the above logic:

  507     ifeq ($(OPT_CFLAGS/$(BUILDARCH)),)
  508       ifeq ($(USE_CLANG), true)
  509         # Clang doesn't understand -gstabs
  510         OPT_CFLAGS += -g
  511       else
  512         OPT_CFLAGS += -gstabs
  513       endif
  514     endif

else you again fail to set -g or -gstabs on the "by-file" definitions.

Also looking at the change in make/solaris/makefiles/amd64.make you have 
taken the file specific flags:

  OPT_CFLAGS/generateOptoStub.o = -xO2

and added the generic OPT_CFLAGS value:

OPT_CFLAGS/generateOptoStub.o = $(OPT_CFLAGS) -xO2

which seems extremely dubious from a correctness perspective.

Thanks,
David
-----

>>>> ---
>>>>
>>>> make/bsd/makefiles/saproc.make
>>>>
>>>> ! # Order src files alfabetically
>>>>
>>>> That would be "alphabetically". But that list doesn't seem alphabetic
>>>> anyway: MacosxDebuggerLocal.m would come after libproc_impl.c; and
>>>> $(AGENTDIR) should come first. I really see no point in forcing such
>>>> lists to be in alphabetic order.
>>>>
>>> This is to make comparison of binaries between the old hotspot build and
>>> the new hotspot build easier. In build-infra, we $(sort ) the object
>>> files before linking to get a reproducible order. The linker output is
>>> affected by the order of the object files. By making sure the old and
>>> the new build sorts them the same way, we get cleaner comparisons and
>>> can more easily detect other types of differences through those
>>> comparisons. The sort order isn't strictly alphabetical, it's on byte
>>> order so upper case goes before lower case.
>>
>> I saw the change for the ordered object files on Windows, but this
>> simply orders source files in a list. Not sure how that has any affect
>> on the linking ??
>>
> It has an effect on the linking because that list is used verbatim on
> the combined compile/link command line.
>
> /Erik
>> Cheers,
>> David
>>
>>> /Erik
>>>> make/linux/makefiles/saproc.make doesn't have the comment that was
>>>> added for bsd.
>>>>
>>>> ----
>>>>
>>>> make/solaris/makefiles/amd64.make
>>>>
>>>> Similar issue with bsd amd64.make. Not sure what you are trying to
>>>> achieve here - is it some kind of last option wins situation ?
>>>>
>>>> ---
>>>>
>>>> make/windows/create_obj_files.sh
>>>>
>>>> Harmless I guess but not sure about relevance of sort order here.
>>>>
>>>> ----
>>>>
>>>>  src/share/vm/adlc/adlparse.cpp
>>>>
>>>> So that's where that comes from! :)
>>>>
>>>> ---
>>>>
>>>> src/share/vm/gc/g1/g1EvacStats.cpp
>>>>
>>>> I don't see anything in the cpp files that uses anything from the
>>>> atomic class ???
>>>>
>>>>
>>>> Thanks,
>>>> David
>>>>
>>>>
>>>>>
>>>>> /Magnus
>>>>>
>>>>>>
>>>>>> Otherwise looks good.
>>>>>>
>>>>>> /Erik
>>>>>>
>>>>>> On 2015-11-13 03:34, Magnus Ihse Bursie wrote:
>>>>>>> In the new hotspot build project, we have made a few changes to the
>>>>>>> existing build. In preparation for the new build, I'd like to
>>>>>>> integrate these into mainline.
>>>>>>>
>>>>>>> These changes are:
>>>>>>> * When overriding optimization, do not lose current debug (-g)
>>>>>>> setting (!)
>>>>>>> * Make adlc actually quiet in quiet mode
>>>>>>> * Make g1EvacStats.cpp compile in all cases without precompiled
>>>>>>> headers
>>>>>>> * Sort saproc object files when linking (facilitates comparison to
>>>>>>> new build)
>>>>>>>
>>>>>>> Unless someone suggests otherwise, I intend to push this (using
>>>>>>> JPRT)
>>>>>>> to hs-rt.
>>>>>>>
>>>>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8142909
>>>>>>> WebRev:
>>>>>>> http://cr.openjdk.java.net/~ihse/JDK-8142909-hotspot-build-infra-integration/webrev.01
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> /Magnus
>>>>>>
>>>>>
>>>
>

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