We were able to assemble, but not disassemble.
Note that fixupRMValue was truncating EA_REG_BND0-3 because we hit
the uint8_t max. The control registers were already squarely above
it, but I don't think they ever go in .r/m, only in .reg.
I also did notice an extra REX.W in our encoding, but I think that's
fine.
llvm-svn: 275427
This is a fix for disassembling unusual instruction sequences in 64-bit
mode w.r.t the CALL rel16 instruction. It might be desirable to move the
check somewhere else, but it essentially mimics the special case
handling with JCXZ in 16-bit mode.
The current behavior accepts the opcode size prefix and causes the
call's immediate to stop disassembling after 2 bytes. When debugging
sequences of instructions with this pattern, the disassembler output
becomes extremely unreliable and essentially useless (if you jump midway
into what lldb thinks is a unified instruction, you'll lose %rip). So we
ignore the prefix and consume all 4 bytes when disassembling a 64-bit
mode binary.
Note: in Vol. 2A 3-99 the Intel spec states that CALL rel16 is N.S. N.S.
is defined as:
Indicates an instruction syntax that requires an address override
prefix in 64-bit mode and is not supported. Using an address
override prefix in 64-bit mode may result in model-specific
execution behavior. (Vol. 2A 3-7)
Since 0x66 is an operand override prefix we should be OK (although we
may want to warn about 0x67 prefixes to 0xe8). On the CPUs I tested
with, they all ignore the 0x66 prefix in 64-bit mode.
Patch by Matthew Barney!
Differential Revision: http://reviews.llvm.org/D9573
llvm-svn: 246038
- Deciding that insn->sibIndex is SIB_INDEX_NONE does not require another
check beyond the fully decoded bits being equal to 0x4.
The expression insn->sibIndex == SIB_INDEX_sib could not have been true unless
index were 0x4, because SIB_INDEX_sib is merely the range base (SIB_INDEX_EAX)
plus 4. Respectively SIB_INDEX_sib64.
- Don't use a switch statement to perform left-shift.
Differential Revision: http://reviews.llvm.org/D9762
llvm-svn: 240598
Simplify boolean expressions with `true` and `false` with `clang-tidy`
Patch by Richard Thomson.
Differential Revision: http://reviews.llvm.org/D8519
llvm-svn: 233002
Unfortunately, this isn't easy to fix since there's no simple way to figure out from the disassembler tables whether the W-bit is being used to select a 64-bit GPR or if its a required part of the opcode. The fix implemented here just looks for "64" in the instruction name and ignores the W-bit in 32-bit mode if its present.
Fixes PR21169.
llvm-svn: 219194
There are two parts here. First is to modify tablegen to adjust the encoding
type ENCODING_RM with the scaling factor.
The second is to use the new encoding types to compute the correct
displacement in the decoder.
Fixes <rdar://problem/17608489>
llvm-svn: 213281
V' bit in the P2 byte of the EVEX prefix provides the top bit of the NDD and
NDS register fields. This was simply not used in the decoder until now.
Fixes <rdar://problem/17402661>
llvm-svn: 211565
X86_MAX_OPERANDS is changed to unsigned.
Also, add range-based for loops for affected loops. This in turn
needed an ArrayRef instead of a pointer-to-array in
InternalInstruction.
llvm-svn: 207413
reason to expose a global symbol 'decodeInstruction' nor to pollute the global
scope with a bunch of external linkage entities (some of which conflict with
others elsewhere in LLVM).
This is just the initial transition to C++; more cleanups to follow.
llvm-svn: 206717
Ahmed Bougacha