Commit Graph

4 Commits

Author SHA1 Message Date
Rafael Espindola 9f92995781 Don't pass the code model to MC
I was surprised to see the code model being passed to MC. After all,
it assembles code, it doesn't create it.

The one place it is used is in the expansion of .cfi directives to
handle .eh_frame being more that 2gb away from the code.

As far as I can tell, gnu assembler doesn't even have an option to
enable this. Compiling a c file with gcc -mcmodel=large produces a
regular looking .eh_frame. This is probably because in practice linker
parse and recreate .eh_frames.

In llvm this is used because the JIT can place the code and .eh_frame
very far apart. Ideally we would fix the jit and delete this
option. This is hard.

Apart from confusion another problem with the current interface is
that most callers pass CodeModel::Default, which is bad since MC has
no way to map it to the target default if it actually needed to.

This patch then replaces the argument with a boolean with a default
value. The vast majority of users don't ever need to look at it. In
fact, only CodeGen and llvm-mc use it and llvm-mc just to enable more
testing.

llvm-svn: 309884
2017-08-02 20:32:26 +00:00
Rafael Espindola b20b70687a Use SHT_X86_64_UNWIND on every OS.
That is the ABI required type. Linkers still check the section name, so
everything should still work.

llvm-svn: 252300
2015-11-06 13:35:35 +00:00
Rafael Espindola a7c3163cdf Use CIE version 1 for .eh_frame.
According to

http://www.linuxbase.org/betaspecs/lsb/LSB-Core-generic/LSB-Core-generic/ehframechpt.html

we should always use 1.

llvm-svn: 235923
2015-04-27 22:04:24 +00:00
Rafael Espindola d11591b293 Commit back the correct bits of r222760 (was r222538).
I also added a test.

Original message:

Allow FDE references outside the +/-2GB range supported by PC relative
offsets for code models other than small/medium. For JIT application,
memory layout is less controlled and can result in truncations
otherwise.

Patch from Akos Kiss.

Differential Revision: http://reviews.llvm.org/D6079

llvm-svn: 222897
2014-11-27 17:13:56 +00:00