MC assertion failure on .private_extern when producing ELF object code

[llvmbot]

Bugzilla Link	9291
Resolution	WONTFIX
Resolved on	Apr 18, 2019 07:03
Version	trunk
OS	Linux
Attachments	test case
Reporter	LLVM Bugzilla Contributor

Extended Description

Hello,

I accidentally discovered that llvm-mc (r126241) does not fail nicely when it tries to generate ELF object code and encounters the .private_extern assembler directive (which, afaikt only works with Mach-O). The expected behaviour would be to issue an error message that the directive is unsupported for ELF object code, the actual behaviour is the following

llvm-mc: MCELFStreamer.cpp:276: virtual void::MCELFStreamer::EmitSymbolAttribute(llvm::MCSymbol*, llvm::MCSymbolAttr): Assertion `0 && "Invalid symbol attribute for ELF!"' failed.
0 llvm-mc 0x0000000000b535df
1 llvm-mc 0x0000000000b55842
2 libpthread.so.0 0x00007fc8e5d82f60
3 libc.so.6 0x00007fc8e4e8d165 gsignal + 53
4 libc.so.6 0x00007fc8e4e8ff70 abort + 384
5 libc.so.6 0x00007fc8e4e862b1 __assert_fail + 241
6 llvm-mc 0x0000000000afcf22
7 llvm-mc 0x000000000079a3f6
8 llvm-mc 0x00000000007a0b22
9 llvm-mc 0x00000000007a0df1
10 llvm-mc 0x000000000040a489
11 llvm-mc 0x000000000040b108
12 libc.so.6 0x00007fc8e4e79c4d __libc_start_main + 253
13 llvm-mc 0x0000000000406b29
Stack dump:
0. Program arguments: llvm-mc --filetype=obj private_extern.s

Attached is a test-case that demonstrates the problem.

[llvmbot]

Closing old bugs. If this is still relevant, please reopen.