sparcv9 unsupported argument '-Av9b' to option '-Wa,'

[bsdkurt]

oracle$ echo | clang -Wa,-Av9b -x c -
clang: error: unsupported argument '-Av9b' to option '-Wa,'

oracle$ clang -v
OpenBSD clang version 19.1.7
Target: sparc64-unknown-openbsd7.6
Thread model: posix
InstalledDir: /usr/bin

-Wa,-Av9b is supported by gcc on sparc and it would be helpful if clang would support it as well so makefiles don't have to conditionally use -Wa,-mcpu=niagara for clang and -Wa,-Av9b for gcc.

[llvmbot]

@llvm/issue-subscribers-clang-driver

Author: Kurt Miller (bsdkurt)

oracle$ echo | clang -Wa,-Av9b -x c - clang: error: unsupported argument '-Av9b' to option '-Wa,'

oracle$ clang -v
OpenBSD clang version 19.1.7
Target: sparc64-unknown-openbsd7.6
Thread model: posix
InstalledDir: /usr/bin

-Wa,-Av9b is supported by gcc on sparc and it would be helpful if clang would support it as well so makefiles don't have to conditionally use -Wa,-mcpu=niagara for clang and -Wa,-Av9b for gcc.

[bsdkurt]

There are some similar issues in the space and I'm unsure if I should open additional bug reports - all sparc related.

1. clang -x assembler-with-cpp does not respect the default CPU that clang without -x assemebler-with-cpp does. clang without -x assembler-with-cpp sets -Av9a as the default CPU for Linux, FreeBSD and OpenBSD:
   https://clang.llvm.org/doxygen/Driver_2ToolChains_2Arch_2Sparc_8cpp_source.html

2. clang -x assembler-with-cpp -Wa,-mcpu=ultrasparc does not change the instruction set to v9a and errors when v9a instructions are used:
   /usr/xenocara/driver/xf86-video-sunffb/src/VISmoveImage.s:2436:2: error: instruction requires a CPU feature not currently enabled
   faligndata %f42, %f44, %f26

The workaround for 2 is to use clang -x assembler-with-cpp -mcpu=ultrasparc

Please let me know if the above should be their own bug reports or can be a part of this bug report.

[brad0]

@koachan

[koachan]

Ah, for the avilability of -Av9b and friends there's an open PR at #125151

For the assembler-with-cpp issues, I'll look into it, thanks thanks.

[koachan]

1. clang -x assembler-with-cpp does not respect the default CPU that clang without -x assemebler-with-cpp does. clang without -x assembler-with-cpp sets -Av9a as the default CPU for Linux, FreeBSD and OpenBSD:
   https://clang.llvm.org/doxygen/Driver_2ToolChains_2Arch_2Sparc_8cpp_source.html

When assembling with IAS clang seems to not enable VIS (-Av9a) by default. Should be fixed in #130108.

2. clang -x assembler-with-cpp -Wa,-mcpu=ultrasparc does not change the instruction set to v9a and errors when v9a instructions are used:
   /usr/xenocara/driver/xf86-video-sunffb/src/VISmoveImage.s:2436:2: error: instruction requires a CPU feature not currently enabled
   faligndata %f42, %f44, %f26

The workaround for 2 is to use clang -x assembler-with-cpp -mcpu=ultrasparc

Now that #125151 is merged, clang -x assembler-with-cpp -Wa,-Av9a should work. Would that be okay, or do you still need -Wa,-mcpu=ultrasparc flag?

[bsdkurt]

1. clang -x assembler-with-cpp does not respect the default CPU that clang without -x assemebler-with-cpp does. clang without -x assembler-with-cpp sets -Av9a as the default CPU for Linux, FreeBSD and OpenBSD:
   https://clang.llvm.org/doxygen/Driver_2ToolChains_2Arch_2Sparc_8cpp_source.html

When assembling with IAS clang seems to not enable VIS (-Av9a) by default. Should be fixed in #130108.

Thank you.

2. clang -x assembler-with-cpp -Wa,-mcpu=ultrasparc does not change the instruction set to v9a and errors when v9a instructions are used:
   /usr/xenocara/driver/xf86-video-sunffb/src/VISmoveImage.s:2436:2: error: instruction requires a CPU feature not currently enabled
   faligndata %f42, %f44, %f26

The workaround for 2 is to use clang -x assembler-with-cpp -mcpu=ultrasparc

Now that #125151 is merged, clang -x assembler-with-cpp -Wa,-Av9a should work. Would that be okay, or do you still need -Wa,-mcpu=ultrasparc flag?

We don't need the -Wa,-mcpu=ultrasparc flag. I only tried this to find a workaround for the missing support for clang -x assembler-with-cpp -Wa,-Av9a.

BTW, I back ported your inital version of #125151 to clang 19 and tested it on OpenBSD/sparc64 - works as intended. I'll back port the committed version and also #130108 and retest. It will take a few days before I can report back.

[bsdkurt]

Now that #125151 is merged, clang -x assembler-with-cpp -Wa,-Av9a should work. Would that be okay, or do you still need -Wa,-mcpu=ultrasparc flag?

We don't need the -Wa,-mcpu=ultrasparc flag. I only tried this to find a workaround for the missing support for clang -x assembler-with-cpp -Wa,-Av9a.

BTW, I back ported your inital version of #125151 to clang 19 and tested it on OpenBSD/sparc64 - works as intended. I'll back port the committed version and also #130108 and retest. It will take a few days before I can report back.

Following up on this. Back porting the committed version of #125151 to llvm 19 on OpenbSD/sparc64 together with #130108 both work well. Thank you.