Hello,
// 1.s
.abiversion 2
mfspr 8, ABCD
// clang -c -mcpu=power9 -target ppc64le 1.s
The command successfully assembles the source into an object file.
The disassembly shows the instruction emitted:
a6 1a 10 7d: mfspr 8, 112
112 is 0x70.
GNU as throws unsupported relocation error, and doesn't assemble.
This causes problems when a .S is passed to clang for preprocessing
and if the usage of a #define has a typo - clang doesn't catch it.
Thanks,
amol
Hi Amol:
Thanks for reporting this issue.
I believe you are using release build of clang.
If you use assert enabled clang, you should get an assert similar to this:
clang-12: …/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp:252: int64_t (anonymous namespace)::PPCOperand::getImm() const: Assertion `Kind == Immediate && “Invalid access!”’ failed.
I would say this is somehow a known limitation of current asmparser – the error detection/reporting mechanism is not that user friendly…
I would recommend you open a bugzilla for future enhancement https://bugs.llvm.org/. Thanks.
Best,
Jinsong Ji (纪金松), PhD.
XL/LLVM on Power Compiler Development
E-mail: jji@us.ibm.com
Amol via llvm-dev —11/01/2020 09:20:29 AM—Hello, // 1.s