On 07/14/14 04:58 PM, Michael Jones wrote:
Karel,
Thanks. This helps.
If I understand, you have Linux running on a Panda, and on that Panda system you have gcc, and you compile GHC on the Panda itself, rather than build a cross compiler. I can see the advantage of building this way.
Correct!
As far as cross compilers, I have a reason for trying to build a cross compiler, other than the ability to keep the image of the target small. That is, eventually, I want to be able to compile for an RTOS and/or bare iron system. I decided that learning to cross compile for Linux first would be a good approach. Learn the build system on something known to work. So I probably will not give up on that.
That is right, in future I'd also like to give a try to port GHC to some free RTOS and for this I'd need to use cross-compiling anyway, so I'll be on the same boat...
I got a book on Autoconfig. I’ll just have to dig a level deeper into the whole build system. Mainly it means learning the M4 system. I have never used it.
Below are the defines from the command you suggested. Thanks for that, got me over an ignorance hump. At least this define, __ARM_ARCH_5T__, is in the aclocal.m4 file. So I will have to study the macros until I figure out what controls the gcc options passed to the gcc cross compiler. I guess my question is what actually controls this result ("target arch", "ArchARM {armISA = ARMv7, armISAExt = [VFPv3,NEON], armABI = HARD}”)?
Are these controlled by the defines below, or are they controlled by passing gcc arguments to the gcc compiler when the Haskell compiler calls gcc?
Basically speaking all those are controlled by platform gcc. That means if you pass the right option to your cross-compiling gcc you should also get the same result, so for example if you use: gcc -mfloat-abi=hard -march=armv7-a -mfpu=vfpv3-d16 you should get the same settings like me. But anyway, please note that ABI you set to your cross-compiler *have to* match the ABI provided by the target RTOS/OS! I hope that's clear. :-) Cheers, Karel