Summary:
The LLVM disassembler assumes that the unused src0 operand of v_nop is
zero. Other tools can put another value in that field, which is still
valid. This commit fixes the LLVM disassembler to recognize such an
encoding as v_nop, in the same way as we already do for s_getpc.
Differential Revision: https://reviews.llvm.org/D63724
Change-Id: Iaf0363eae26ff92fc4ebc716216476adbff37a6f
llvm-svn: 364208
Changes:
- Added disassembler project
- Fixed all decoding conflicts in .td files
- Added DecoderMethod=“NONE” option to Target.td that allows to
disable decoder generation for an instruction.
- Created decoding functions for VS_32 and VReg_32 register classes.
- Added stubs for decoding all register classes.
- Added several tests for disassembler
Disassembler only supports:
- VI subtarget
- VOP1 instruction encoding
- 32-bit register operands and inline constants
[Valery]
One of the point that requires to pay attention to is how decoder
conflicts were resolved:
- Groups of target instructions were separated by using different
DecoderNamespace (SICI, VI, CI) using similar to AssemblerPredicate
approach.
- There were conflicts in IMAGE_<> instructions caused by two
different reasons:
1. dmask wasn’t specified for the output (fixed)
2. There are image instructions that differ only by the number of
the address components but have the same encoding by the HW spec. The
actual number of address components is determined by the HW at runtime
using image resource descriptor starting from the VGPR encoded in an
IMAGE instruction. This means that we should choose only one instruction
from conflicting group to be the rule for decoder. I didn’t find the way
to disable decoder generation for an arbitrary instruction and therefore
made a onelinear fix to tablegen generator that would suppress decoder
generation when DecoderMethod is set to “NONE”. This is a change that
should be reviewed and submitted first. Otherwise I would need to
specify different DecoderNamespace for every instruction in the
conflicting group. I haven’t checked yet if DecoderMethod=“NONE” is not
used in other targets.
3. IMAGE_GATHER decoder generation is for now disabled and to be
done later.
[/Valery]
Patch By: Sam Kolton
Differential Revision: http://reviews.llvm.org/D16723
llvm-svn: 261185
Tim Renouf