Currently the ARM backend only accpets constant expressions as the
immediate operand in load and store instructions. This allows the
result of symbolic expressions to be used in memory instructions. For
example,
0:
.space 2048
strb r2, [r0, #(.-0b)]
would be assembled into the following instructions.
strb r2, [r0, #2048]
This only adds support to ldr, ldrb, str, and strb in arm mode to
address the build failure of Linux kernel for now, but should facilitate
adding support to similar instructions in the future if the need arises.
Link:
https://github.com/ClangBuiltLinux/linux/issues/1329
Reviewed By: peter.smith, nickdesaulniers
Differential Revision: https://reviews.llvm.org/D98916
cfce5b26a8