When we see a non flag-setting instruction for which only the flag-setting
version is available in Thumb1, we should give a better error message than
"invalid instruction".
Differential Revision: https://reviews.llvm.org/D27414
llvm-svn: 288805
Summary:
The assembler currently does not check the branch target for CBZ/CBNZ
instructions, which only permit branching forwards with a positive offset. This
adds validation for the branch target to ensure negative PC-relative offsets are
not encoded into the instruction, whether specified as a literal or as an
assembler symbol.
Reviewers: rengolin, t.p.northover
Subscribers: llvm-commits, rengolin
Differential Revision: https://reviews.llvm.org/D23312
llvm-svn: 278788
This currently breaks the greendragon clang-stage1-configure-RA/ and
brotli. It is probably just uncovering a pre-existing problem. Reverting
temporarily to get the buildbots green again. A reduced testcase will
follow shortly.
This reverts commit r278659.
llvm-svn: 278711
Summary:
The assembler currently does not check the branch target for CBZ/CBNZ
instructions, which only permit branching forwards with a positive offset. This
adds validation for the branch target to ensure negative PC-relative offsets are
not encoded into the instruction, whether specified as a literal or as an
assembler symbol.
Reviewers: rengolin, t.p.northover
Subscribers: llvm-commits, rengolin
Differential Revision: https://reviews.llvm.org/D23312
llvm-svn: 278659
ARMv6K is another layer between ARMV6 and ARMV6T2. This is the LLVM
side of the changes.
ARMV6 family LLVM implementation.
+-------------------------------------+
| ARMV6 |
+----------------+--------------------+
| ARMV6M (thumb) | ARMV6K (arm,thumb) | <- From ARMV6K and ARMV6M processors
+----------------+--------------------+ have support for hint instructions
| ARMV6T2 (arm,thumb,thumb2) | (SEV/WFE/WFI/NOP/YIELD). They can
+-------------------------------------+ be either real or default to NOP.
| ARMV7 (arm,thumb,thumb2) | The two processors also use
+-------------------------------------+ different encoding for them.
Patch by Vinicius Tinti.
llvm-svn: 232468
The ARM Architecture Reference Manual states the following:
LDM{,IA,DB}:
The SP cannot be in the list.
The PC can be in the list.
If the PC is in the list:
• the LR must not be in the list
• the instruction must be either outside any IT block, or the last
instruction in an IT block.
POP:
The PC can be in the list.
If the PC is in the list:
• the LR must not be in the list
• the instruction must be either outside any IT block, or the last
instruction in an IT block.
PUSH:
The SP and PC can be in the list in ARM instructions, but not in Thumb
instructions.
STM:{,IA,DB}:
The SP and PC can be in the list in ARM instructions, but not in Thumb
instructions.
llvm-svn: 224502
Certain ARM instructions accept 32-bit immediate operands encoded as a 8-bit
integer value (0-255) and a 4-bit rotation (0-30, even). Current ARM assembly
syntax support in LLVM allows the decoded (32-bit) immediate to be specified
as a single immediate operand for such instructions:
mov r0, #4278190080
The ARMARM defines an extended assembly syntax allowing the encoding to be made
more explicit, as in:
mov r0, #255, #8 ; (same 32-bit value as above)
The behaviour of the two instructions can be different w.r.t flags, which is
documented under "Modified immediate constants" in ARMARM. This patch enables
support for this extended syntax at the MC layer.
llvm-svn: 223113
POP instructions are aliased to the ARM LDM variants but have different syntax.
This caused two problems: we tried to access a non-existent operand to annotate
the '!', and the error message didn't make much sense.
With some vigorous hand-waving in the error message both problems can be
fixed.
llvm-svn: 193322
The set of circumstances where the writeback register is allowed to be in the
list of registers is rather baroque, but I think this implements them all on
the assembly parsing side.
For disassembly, we still warn about an ARM-mode LDM even if the architecture
revision is < v7 (the required architecture information isn't available). It's
a silly instruction anyway, so hopefully no-one will mind.
rdar://problem/15223374
llvm-svn: 193185
The hint instructions ("nop", "yield", etc) are mostly Thumb2-only, but have
been ported across to the v6M architecture. Fortunately, v6M seems to sit
nicely between v6 (thumb-1 only) and v6T2, so we can add a feature for it
fairly easily.
rdar://problem/15144406
llvm-svn: 192097
Changing the diagnostic message for out of range branch targets in 191686 broke the tests.
The diagnostic message for out of range branch targets was changed to be more consistent with the other diagnostics.
llvm-svn: 191691
These were pretty straightforward instructions, with some assembly support
required for HLT.
The ARM assembler is keen to split the instruction mnemonic into a
(non-existent) 'H' instruction with the LT condition code. An exception for
HLT is needed.
HLT follows the same rules as BKPT when in IT blocks, so the special BKPT
hadling code has been adapted to handle HLT also.
Regression tests added including diagnostic tests for out of range immediates
and illegal condition codes, as well as negative tests for pre-ARMv8.
llvm-svn: 190053
1. The offset range for Thumb1 PC relative loads is [0..1020] and not [-1024..1020]
2. Thumb2 PC relative loads may define the PC, so the restriction placed on target register is removed
3. Removes unneeded alias between "ldr.n" and t1LDRpci. ".n" is actually stripped by both tablegen
and the ASM parser, so this alias rule really does nothing
llvm-svn: 188466
The long encoding for Thumb2 unconditional branches is broken.
Additionally, there is no range checking for target operands; as such
for instructions originating in assembly code, only short Thumb encodings
are generated, regardless of the bitsize needed for the offset.
Adding range checking is non trivial due to the representation of Thumb
branch instructions. There is no true difference between conditional and
unconditional branches in terms of operands and syntax - even unconditional
branches have a predicate which is expected to match that of the IT block
they are in. Yet, the encodings and the permitted size of the offset differ.
Due to this, for any mnemonic there are really 4 encodings to choose for.
The problem cannot be handled in the parser alone or by manipulating td files.
Because the parser builds first a set of match candidates and then checks them
one by one, whatever tablegen-only solution might be found will ultimately be
dependent of the parser's evaluation order. What's worse is that due to the fact
that all branches have the same syntax and the same kinds of operands, that
order is governed by the lexicographical ordering of the names of operand
classes...
To circumvent all this, any necessary disambiguation is added to the instruction
validation pass.
llvm-svn: 188067
Make sure when parsing the Thumb1 sp+register ADD instruction that
the source and destination operands match. In thumb2, just use the
wide encoding if they don't. In Thumb1, issue a diagnostic.
rdar://11219154
llvm-svn: 155748
When an instruction match is found, but the subtarget features it
requires are not available (missing floating point unit, or thumb vs arm
mode, for example), issue a diagnostic that identifies what the feature
mismatch is.
rdar://11257547
llvm-svn: 155499
Outside an IT block, "add r3, #2" should select a 32-bit wide encoding
rather than generating an error indicating the 16-bit encoding is only
legal in an IT block (outside, the 'S' suffic is required for the 16-bit
encoding).
rdar://10348481
llvm-svn: 143201
Fix base register type and canonicallize to the "ldm" spelling rather than
"ldmia." Add diagnostics for incorrect writeback token and out-of-range
registers.
llvm-svn: 137986
Oliver Stannard