When writing a unit test on replacing standard epilogue sequences with `BR __mspabi_func_epilog_<N>`, by manually asm-clobbering `rN` - `r10` for N = 4..10, everything worked well except for seeming inability to clobber r4.
The problem was that MSP430 code generator of LLVM used an obsolete name FP for that register. Things were worse because when `llc` read an unknown register name, it silently ignored it.
That is, I cannot use `fp` register name from the C code because Clang does not accept it (exactly like GCC). But the accepted name `r4` is not recognised by `llc` (it can be used in listings passed to `llvm-mc` and even `fp` is replace to `r4` by `llvm-mc`). So I can specify any of `fp` or `r4` for the string literal of `asm(...)` but nothing in the clobber list.
This patch replaces `MSP430::FP` with `MSP430::R4` in the backend code (even [MSP430 EABI](http://www.ti.com/lit/an/slaa534/slaa534.pdf) doesn't mention FP as a register name). The R0 - R3 registers, on the other hand, are left as is in the backend code (after all, they have some special meaning on the ISA level). It is just ensured clang is renaming them as expected by the downstream tools. There is probably not much sense in **marking them clobbered** but rename them //just in case// for use at potentially different contexts.
Differential Revision: https://reviews.llvm.org/D82184
When writing a unit test on replacing standard epilogue sequences with `BR __mspabi_func_epilog_<N>`, by manually asm-clobbering `rN` - `r10` for N = 4..10, everything worked well except for seeming inability to clobber r4.
The problem was that MSP430 code generator of LLVM used an obsolete name FP for that register. Things were worse because when `llc` read an unknown register name, it silently ignored it.
Differential Revision: https://reviews.llvm.org/D82184
Reapply r346374 with the fixes for modules build.
Original summary:
This change implements assembler parser, code emitter, ELF object writer
and disassembler for the MSP430 ISA. Also, more instruction forms are added
to the target description.
Patch by Michael Skvortsov!
llvm-svn: 346948
Summary:
This change implements assembler parser, code emitter, ELF object writer
and disassembler for the MSP430 ISA. Also, more instruction forms are added
to the target description.
Reviewers: asl
Reviewed By: asl
Subscribers: pftbest, krisb, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D53661
llvm-svn: 346374
Anatoly Trosinenko