John Leidel (jleidel)
2014-Dec-10 21:07 UTC
[LLVMdev] llvm-mc support for .cpu directive or AArch64
All, we’ve been running some internal tests with the various LLVM backend
utilities. In running some simply assembler tests for llvm-mc (3.5 release
tree), we’ve found that the “.cpu” directive is not currently supported. We
generated an assembly file using the GNU-Linaro GCC 4.8.0 for AArch64 that
contains this directive. The assembly looks similar to the following:
.cpu generic+fp+simd
.file "arm.c"
.text
.align 2
.global __arm_function
.type __arm_function, %function
__arm_function:
sub sp, sp, #16
llvm-mc complains when we attempt to assemble it:
arm.s:1:2: error: unknown directive
.cpu generic+fp+simd
It seems somewhat logical that this directive wouldn’t be inherently necessary
given the way that the backends (et.al. assembler, dissasmbler templates) are
functionally organized in LLVM. However, does anyone have any plans to
implement this directive? I would prefer not to parse+ignore it. Are there any
other known common directives from other codegens that don’t work?
cheers
john
—John D. Leidel
Renato Golin
2014-Dec-11 10:15 UTC
[LLVMdev] llvm-mc support for .cpu directive or AArch64
To whomever plan to implement that, please be wary of this bug: http://llvm.org/bugs/show_bug.cgi?id=20757 and add a FIXME to that effect, as we did on ARM. Also, we're planning on implementing a push/pop mechanism to make it sane to use cpu/fpu directives. cheers, --renato On 10 December 2014 at 21:07, John Leidel (jleidel) <jleidel at micron.com> wrote:> All, we’ve been running some internal tests with the various LLVM backend utilities. In running some simply assembler tests for llvm-mc (3.5 release tree), we’ve found that the “.cpu” directive is not currently supported. We generated an assembly file using the GNU-Linaro GCC 4.8.0 for AArch64 that contains this directive. The assembly looks similar to the following: > > .cpu generic+fp+simd > .file "arm.c" > .text > .align 2 > .global __arm_function > .type __arm_function, %function > __arm_function: > sub sp, sp, #16 > > llvm-mc complains when we attempt to assemble it: > arm.s:1:2: error: unknown directive > .cpu generic+fp+simd > > It seems somewhat logical that this directive wouldn’t be inherently necessary given the way that the backends (et.al. assembler, dissasmbler templates) are functionally organized in LLVM. However, does anyone have any plans to implement this directive? I would prefer not to parse+ignore it. Are there any other known common directives from other codegens that don’t work? > > cheers > john > > —John D. Leidel > > _______________________________________________ > LLVM Developers mailing list > LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev