Patch by Mikulas Patocka. I added the test. I checked that for cpu names that
gas knows about, it also doesn't generate nopl.
The modified cpus:
i686 - there are i686-class CPUs that don't have nopl: Via c3, Transmeta
Crusoe, Microsoft VirtualBox - see
https://bbs.archlinux.org/viewtopic.php?pid=775414
k6, k6-2, k6-3, winchip-c6, winchip2 - these are 586-class CPUs
via c3 c3-2 - see https://bugs.archlinux.org/task/19733 as a proof that
Via c3 and c3-Nehemiah don't have nopl
llvm-svn: 195679
This patch fixes a bug in the assembler that was causing bad code to
be emitted. When switching modes in an assembly file (e.g. arm to
thumb mode) we would always emit the opcode from the original mode.
Consider this small example:
$ cat align.s
.code 16
foo:
add r0, r0
.align 3
add r0, r0
$ llvm-mc -triple armv7-none-linux align.s -filetype=obj -o t.o
$ llvm-objdump -triple thumbv7 -d t.o
Disassembly of section .text:
foo:
0: 00 44 add r0, r0
2: 00 f0 20 e3 blx #4195904
6: 00 00 movs r0, r0
8: 00 44 add r0, r0
This shows that we have actually emitted an arm nop (e320f000)
instead of a thumb nop. Unfortunately, this encodes to a thumb
branch which causes bad things to happen when compiling assembly
code with align directives.
The fix is to notify the ARMAsmBackend when we switch mode. The
MCMachOStreamer was already doing this correctly. This patch makes
the same change for the MCElfStreamer.
There is still a bug in the way nops are emitted for alignment
because the MCAlignment fragment does not store the correct mode.
The ARMAsmBackend will emit nops for the last mode it knew about. In
the example above, we still generate an arm nop if we add a `.code
32` to the end of the file.
PR18019
llvm-svn: 195677
These should not use COMDATs. GNU as uses .bss for .lcomm and section 0 for
.comm.
Given
static int a;
int b;
MSVC puts both in .bss. This patch then puts both .comm and .lcomm on .bss. With
this change we agree with gas on .lcomm, are much closer on .comm and clang-cl
matches msvc on the above example.
llvm-svn: 195654
This is the first step to fix pr17918.
It extends the .section directive a bit, inspired by what the ELF one looks
like. The problem with using linkonce is that given
.section foo
.linkonce....
.section foo
.linkonce
we would already have switched sections when getting to .linkonce. The cleanest
solution seems to be to add the comdat information in the .section itself.
llvm-svn: 195148
No true functional changes.
Change the "hack" name of emitMipsHackSTOCG to emitSymSTO.
Remove demonstration code in AsmParser for emitMipsHackSTOCG and
emitMipsHackELFFlags. The STO field is in an ELF symbol and is not
an explicit directive. That said, we are missing the compliment call
in AsmParser and that will need to be addressed soon.
XFAIL dummy tests for emitMipsHackELFFlags and emitMipsHackELFFlags.
These will built out with following patches.
llvm-svn: 195067
This reverts commit r190888, to fix PR17967. The original change wasn't
the right way to get @feat.00 into the object file. The right fix is to
make @feat.00 be a global symbol.
llvm-svn: 195053
The system LDM and STM instructions can't usually writeback to the base
register. The one exception is when an LDM is actually an exception-return
(i.e. contains PC in the register list).
(There's already a test that "ldm sp!, {r0-r3, pc}^" works, which is why there
is no positive test).
rdar://problem/15223374
llvm-svn: 194512
On darwin, when trying to create compact unwind info, a .cfi_cfa_def
directive would case an llvm_unreachable() to be hit. Back off when we
see this directive and generate the regular DWARF style eh_frame.
rdar://15406518
llvm-svn: 194285
Cortex-M0 supports these 32-bit instructions despite being Thumb1 only
(mostly). We knew about that but not that the aliases without the default "sy"
operand were also permitted.
llvm-svn: 194094
This adds a new subtarget feature called FPARMv8 (implied by NEON), and
predicates the support of the FP instructions and registers on this feature.
llvm-svn: 193739
