Re: clang + VFP
Hi Renato, I was trying to experiment with what you mentioned; here: https://pastebin.linaro.org/view/35ea66c1 - it still seems to fail with the same error. Would you please have a look at it, and let me know if you spot something absolutely basic and idiotic? (sorry, and a n00b to llvm / clang world !) Best regards, ~Sumit. On 18 April 2013 13:36, Renato Golin wrote: > Hi Tom, > > On 17 April 2013 21:13, Tom Gall wrote: > >> When the clang .o is linked to the gcc/gcc+, I'm getting >> /home/tgall/opencl/SNU/tmp2/cl_temp_1.tkl uses VFP register arguments, >> /home/tgall/opencl/SNU/tmp2/cl_temp_1.o does not >> > > This is pretty common. Clang assumes ARMv4 unless you're pretty specific > about your core. > > > clang -mfloat-abi=hard -mfpu=neon -S -emit-llvm -x cl >> -I/home/tgall/opencl/SNU/src/compiler/tools/clang/lib/Headers >> -I/home/tgall/opencl/SNU/inc -include >> /home/tgall/opencl/SNU/inc/comp/cl_kernel.h >> /home/tgall/opencl/SNU/tmp2/cl_temp_1.cl -o >> /home/tgall/opencl/SNU/tmp2/cl_temp_1.ll >> > > What target triple do you see when you run: > > $ head /home/tgall/opencl/SNU/tmp2/cl_temp_1.ll > > If it's "arm-blah", then it'll default to ARMv4. It has to be "armv7*" to > default to Cortex-A8, but would be good to specify the CPU as well. It > won't detect from the hardware you're in yet. > > > >> so first obvious question is -mfloat-abi=hard -mfpu=neon correct for >> clang? >> > > Neither required, nor sufficient. ;) > > When you chose your triple "armv7l-*" it'll default to A8, Neon, > hard-float. If you specify hard-float and Neon, it won't default to A8 and > the parameters will be ignored further in. It doesn't make sense, I agree, > and it's a problem not just for cross-compilation, but native. > > The best bet is to specify the triple AND the CPU, so that you're sure > you're getting what you want: > > $ clang -target arm-linux-gnueabihf -mcpu=cortex-a9 -mfpu=neon -mthumb > > As you noticed, Thumb2 is not the default for Cortex-A*, but hard-float > is. You can always see what hidden options you got by adding -v to the > command line. Also, the triple here is "arm-*" but Clang will notice the A9 > option and will change accordingly in the IR and pass the correct options > to the assembler. If you do in two steps, you still have to pass it > yourself, because "armv7-*" in the IR will turn out as Cortex-A8 by default. > > Two other options that I encourage you to try: > > -integrated-as : the experimental (on ARM) integrated assembler. You won't > be using GAS, so if your code depends on GAS' idiosyncrasies, don't use > this option. > > -O3 : Apart from the usual, this will turn on auto-vectorization (like > GCC), which is also kind of experimental. Just be aware of that. > > Hope that helps, > --renato > > PS: If you're cross compiling, you'll have to manually specify the include > paths. > -- Thanks and regards, Sumit Semwal Linaro Kernel Engineer - Graphics working group Linaro.org <http://www.linaro.org/>* **│ *Open source software for ARM SoCs* *** Follow *Linaro: *Facebook <http://www.facebook.com/pages/Linaro> | Twitter<http://twitter.com/#!/linaroorg> | Blog <http://www.linaro.org/linaro-blog/> ___ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
Re: clang + VFP
On 25 April 2013 16:19, Renato Golin wrote: > On 23 April 2013 10:03, Sumit Semwal wrote: >> >> Would you please have a look at it, and let me know if you spot something >> absolutely basic and idiotic? (sorry, and a n00b to llvm / clang world !) > > > I can't see anything wrong with it. > > What I suggest is to start investigating the IR files for clues (especially > the target triple and the aapcs_vfp function attributes), the assembly files > (for build attributes and function prologue) and the objects (for correctly > linked libraries). > > If you use -v on all command lines (clang, gcc, g++, ld) you might spot what > assumptions are being taken and what to do instead. > > cheers, > --renato Sure, Thanks Renato! -- Thanks and regards, Sumit Semwal ___ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
Re: clang + VFP
Hi Renato! Apologies again for troubling you; attached is a log file from one of the builds I am doing (trying to get pocl working on chromebook) - I 'think' I have provided the right values for target etc, but maybe you could have a quick look to spot any quickly visible mismatches? Thanks a bunch! Best regards, ~Sumit. On 25 April 2013 16:37, Sumit Semwal wrote: > On 25 April 2013 16:19, Renato Golin wrote: >> On 23 April 2013 10:03, Sumit Semwal wrote: >>> >>> Would you please have a look at it, and let me know if you spot something >>> absolutely basic and idiotic? (sorry, and a n00b to llvm / clang world !) >> >> >> I can't see anything wrong with it. >> >> What I suggest is to start investigating the IR files for clues (especially >> the target triple and the aapcs_vfp function attributes), the assembly files >> (for build attributes and function prologue) and the objects (for correctly >> linked libraries). >> >> If you use -v on all command lines (clang, gcc, g++, ld) you might spot what >> assumptions are being taken and what to do instead. >> >> cheers, >> --renato > Sure, Thanks Renato! > > > -- > Thanks and regards, > Sumit Semwal -- Thanks and regards, Sumit Semwal Linaro Kernel Engineer - Graphics working group Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog temp.log Description: Binary data ___ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
Re: clang + VFP
Awesome Renato! Thanks a bunch! I'll try it out and let you know! Best, ~Sumit. On 26 April 2013 01:17, Renato Golin wrote: > Hi Sumit, > > I think I've found it! > > You compiled to IR (.bc) by specifying hard-float, but when you convert it > to assembly (where the AAPCS will be lowered), you don't: > > [pocl] executing [/usr/lib/llvm-3.2/bin/llc -relocation-model=pic -o > /tmp/pthread/test_as_type/1-1-1.0-0-0/parallel.s > /tmp/pthread/test_as_type/1-1-1.0-0-0/parallel.bc] > > Later on you pass the hard-float argument to the assembler (clang, which > passes to as), but that's too late. > > If you want to compile in separate steps, you'll have to provide consistent > flags on each step, to make sure nothing is left behind. All tools, clang, > as, llc etc will have to have the same set of flags (or similar flags, if > they accept slightly different syntax). > > Hope that helps! > > --renato > > > On 25 April 2013 15:36, Sumit Semwal wrote: >> >> Hi Renato! >> >> Apologies again for troubling you; attached is a log file from one of >> the builds I am doing (trying to get pocl working on chromebook) - I >> 'think' I have provided the right values for target etc, but maybe you >> could have a quick look to spot any quickly visible mismatches? >> >> Thanks a bunch! >> Best regards, >> ~Sumit. >> >> On 25 April 2013 16:37, Sumit Semwal wrote: >> > On 25 April 2013 16:19, Renato Golin wrote: >> >> On 23 April 2013 10:03, Sumit Semwal wrote: >> >>> >> >>> Would you please have a look at it, and let me know if you spot >> >>> something >> >>> absolutely basic and idiotic? (sorry, and a n00b to llvm / clang world >> >>> !) >> >> >> >> >> >> I can't see anything wrong with it. >> >> >> >> What I suggest is to start investigating the IR files for clues >> >> (especially >> >> the target triple and the aapcs_vfp function attributes), the assembly >> >> files >> >> (for build attributes and function prologue) and the objects (for >> >> correctly >> >> linked libraries). >> >> >> >> If you use -v on all command lines (clang, gcc, g++, ld) you might spot >> >> what >> >> assumptions are being taken and what to do instead. >> >> >> >> cheers, >> >> --renato >> > Sure, Thanks Renato! >> > >> > >> > -- >> > Thanks and regards, >> > Sumit Semwal >> >> >> >> -- >> Thanks and regards, >> >> Sumit Semwal >> >> Linaro Kernel Engineer - Graphics working group >> >> Linaro.org │ Open source software for ARM SoCs >> >> Follow Linaro: Facebook | Twitter | Blog > > -- Thanks and regards, Sumit Semwal Linaro Kernel Engineer - Graphics working group Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog ___ linaro-toolchain mailing list linaro-toolchain@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-toolchain
