Windows breakage -- again

[Johan Tibell]

We are on x86(-64), but not on other archs. Simon, which arch are you on?


On Wed, Jul 16, 2014 at 5:58 PM, Carter Schonwald <
carter.schonwald at gmail.com> wrote:

> Huh. We're not generating the atomics assembly directly ourselves?
>
>
> On Wednesday, July 16, 2014, Johan Tibell <johan.tibell at gmail.com> wrote:
>
>> I added some primops about a month ago
>> (4ee4ab01c1d97845aecb7707ad2f9a80933e7a49) that call __sync_fetch_and_add,
>> a gcc/llvm builtin. I'm a bit surprised to see this error. The GCC manual
>> [1] says:
>>
>> > " Not all operations are supported by all target processors. If a
>> particular operation cannot be implemented on the target processor, a
>> warning will be generated and a call an external function will be
>> generated. The external function will carry the same name as the builtin,
>> with an additional suffix `_n' where n is the size of the data type."
>>
>> I'm a bit surprised by this error for two reasons:
>>
>>  * A call to that symbol should only be generated if the CPU doesn't
>> support the atomic instructions. What CPU model does Windows report that
>> you have?
>>
>>  * gcc should define such a symbol. For me the following test program
>> compiles:
>>
>> #include <stdint.h>
>>
>> uint8_t test(uint8_t* ptr, uint8_t val) {
>>   return __sync_fetch_and_add_1(ptr, val);
>> }
>>
>> int main(void) {
>>   uint8_t n;
>>   return test(&n, 1);
>> }
>>
>> Does that compile for you? Which version of GCC do we end up using on
>> Windows?
>>
>> The reported symbol (___sync_fetch_and_add_1) has three leading
>> underscores, that looks weird. Can you compile just
>> libraries/ghc-prim/cbits/atomic.c and see if it's indeed GCC that generates
>> a reference to that symbol?
>>
>> 1. http://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Atomic-Builtins.html
>>
>>
>> On Wed, Jul 16, 2014 at 12:29 AM, Simon Peyton Jones <
>> simonpj at microsoft.com> wrote:
>>
>>>  Aargh!  The Windows build has broken – again.  I can’t build GHC on my
>>> laptop any more.
>>>
>>> A clean ‘sh validate’ finishes as below.  What on earth is
>>> `___sync_fetch_and_add_1'?
>>>
>>> Can anyone help?  Thanks!
>>>
>>> Simon
>>>
>>> "inplace/bin/ghc-stage2.exe" -hisuf hi -osuf  o -hcsuf hc -static  -H32m
>>> -O -Werror -Wall -H64m -O0    -package-name vector-0.10.9.1
>>> -hide-all-packages -i -ilibraries/vector/.
>>> -ilibraries/vector/dist-install/build
>>> -ilibraries/vector/dist-install/build/autogen
>>> -Ilibraries/vector/dist-install/build
>>> -Ilibraries/vector/dist-install/build/autogen -Ilibraries/vector/include
>>> -Ilibraries/vector/internal   -optP-DVECTOR_BOUNDS_CHECKS -optP-include
>>> -optPlibraries/vector/dist-install/build/autogen/cabal_macros.h -package
>>> base-4.7.1.0 -package deepseq-1.3.0.2 -package ghc-prim-0.3.1.0 -package
>>> primitive-0.5.2.1 -O2 -XHaskell98 -XCPP -XDeriveDataTypeable -O2 -O
>>> -dcore-lint -fno-warn-deprecated-flags  -no-user-package-db -rtsopts
>>> -Wwarn     -odir libraries/vector/dist-install/build -hidir
>>> libraries/vector/dist-install/build -stubdir
>>> libraries/vector/dist-install/build   -c
>>> libraries/vector/./Data/Vector/Fusion/Stream/Monadic.hs -o
>>> libraries/vector/dist-install/build/Data/Vector/Fusion/Stream/Monadic.o
>>>
>>> Loading package ghc-prim ... linking ... ghc-stage2.exe: unable to load
>>> package `ghc-prim'
>>>
>>> ghc-stage2.exe:
>>> C:\code\HEAD\libraries\ghc-prim\dist-install\build\HSghc-prim-0.3.1.0.o:
>>> unknown symbol `___sync_fetch_and_add_1'
>>>
>>> libraries/vector/ghc.mk:5: recipe for target
>>> 'libraries/vector/dist-install/build/Data/Vector/Fusion/Stream/Monadic.o'
>>> failed
>>>
>>> make[1]: ***
>>> [libraries/vector/dist-install/build/Data/Vector/Fusion/Stream/Monadic.o]
>>> Error 1
>>>
>>>
>>>
>>> I
>>>
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>>> ghc-devs at haskell.org
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>>>
>>>
>>
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