As of rev ea222be0d, LLVMs assembler will actually try to honour the
"fill value" part of p2align directives. X86 printed these as 0x90, which
isn't actually what it wanted: we want multi-byte nops for .text
padding. Compiling via a textual assembly file produces single-byte
nop padding since ea222be0d but the built-in assembler will produce
multi-byte nops. This divergent behaviour is undesirable.
To fix: don't set the byte padding field for x86, which allows the
assembler to pick multi-byte nops. Test that we get the same multi-byte
padding when compiled via textual assembly or directly to object file.
Added same-align-bytes-with-llasm-llobj.ll to that effect, updated
numerous other tests to not contain check-lines for the explicit padding.
This patch makes LLVM emit line 0 source locations for nops emitted as
basic block padding.
---------
Co-authored-by: Orlando Cazalet-Hyams <orlando.hyams@sony.com>
