This patch should not introduce any behavior changes. It consists of
mostly one of two changes:
1. Replacing fall through comments with the LLVM_FALLTHROUGH macro
2. Inserting 'break' before falling through into a case block consisting
of only 'break'.
We were already using this warning with GCC, but its warning behaves
slightly differently. In this patch, the following differences are
relevant:
1. GCC recognizes comments that say "fall through" as annotations, clang
doesn't
2. GCC doesn't warn on "case N: foo(); default: break;", clang does
3. GCC doesn't warn when the case contains a switch, but falls through
the outer case.
I will enable the warning separately in a follow-up patch so that it can
be cleanly reverted if necessary.
Reviewers: alexfh, rsmith, lattner, rtrieu, EricWF, bollu
Differential Revision: https://reviews.llvm.org/D53950
llvm-svn: 345882
The behavior in 64-bit mode is different between Intel and AMD CPUs. Intel ignores the 0x66 prefix. AMD does not. objump doesn't ignore the 0x66 prefix. Since LLVM aims to match objdump behavior, we should do the same.
While I was trying to fix this I had change brtarget16/32 to use ENCODING_IW/ID instead of ENCODING_Iv to get the 0x66+REX.W case to act sort of sanely. It's still wrong, but that's a problem for another day.
The change in encoding exposed the fact that 16-bit mode disassembly of relative jumps was creating JMP_4 with a 2 byte immediate. It should have been JMP_2. From just printing you can't tell the difference, but if you dumped the encoding it wouldn't have matched what we started with.
While fixing that, it exposed that jo/jno opcodes were missing from the switch that this patch deleted and there were no test cases for them.
Fixes PR38537.
llvm-svn: 339622
Summary:
If LOCK prefix is not the first prefix in an instruction, LLVM
disassembler silently drops the prefix.
The fix is to select a proper instruction with a builtin LOCK prefix if
one exists.
Reviewers: craig.topper
Reviewed By: craig.topper
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D49001
llvm-svn: 336400
These encodings correspond to the cases in the normal encoding scheme where there is no index and our modrm reading code initially decodes it as such. The VSIB handling code tried to compensate for this, but failed to add the base needed to make later code do the right thing.
Fixes PR37712.
llvm-svn: 334121
A 5-bit value can occur when EVEX.X is 0 due to it being used to extend modrm.rm to encode XMM16-31. But if modrm.rm instead encodes a GPR, the Intel documentation says EVEX.X should be ignored so just mask it to 4 bits once we know its a GPR.
llvm-svn: 333725
This was an accidental side effect of EVEX.X being used to encode XMM16-XMM31 using modrm.rm with modrm.mod==0x3.
I think there are still more bugs related to this.
llvm-svn: 333722
Three new instructions:
umonitor - Sets up a linear address range to be
monitored by hardware and activates the monitor.
The address range should be a writeback memory
caching type.
umwait - A hint that allows the processor to
stop instruction execution and enter an
implementation-dependent optimized state
until occurrence of a class of events.
tpause - Directs the processor to enter an
implementation-dependent optimized state
until the TSC reaches the value in EDX:EAX.
Also modifying the description of the mfence
instruction, as the rep prefix (0xF3) was allowed
before, which would conflict with umonitor during
disassembly.
Before:
$ echo 0xf3,0x0f,0xae,0xf0 | llvm-mc -disassemble
.text
mfence
After:
$ echo 0xf3,0x0f,0xae,0xf0 | llvm-mc -disassemble
.text
umonitor %rax
Reviewers: craig.topper, zvi
Reviewed By: craig.topper
Differential Revision: https://reviews.llvm.org/D45253
llvm-svn: 330462
Summary:
This patch makes the decoder understand old AMD 3DNow!
instructions that have never been properly supported in the X86
disassembler, despite being supported in other subsystems. Hopefully
this should make the X86 decoder more complete with respect to binaries
containing legacy code.
Reviewers: craig.topper
Reviewed By: craig.topper
Subscribers: llvm-commits, maksfb, bruno
Differential Revision: https://reviews.llvm.org/D43311
llvm-svn: 325295
This introduces a new operand type to encode the whether the index register should be XMM/YMM/ZMM. And new code to fixup the results created by readSIB.
This has the nice effect of removing a bunch of code that hard coded the name of every GATHER and SCATTER instruction to map the index type.
This fixes PR32807.
llvm-svn: 316273
Differential Revision: https://reviews.llvm.org/D36788
M lib/Target/X86/Disassembler/X86DisassemblerDecoder.cpp
M lib/Target/X86/Disassembler/X86DisassemblerDecoder.h
A test/MC/Disassembler/X86/prefixes-i386.s
A test/MC/Disassembler/X86/prefixes-x86_64.s
M test/MC/Disassembler/X86/prefixes.txt
llvm-svn: 311882
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.
I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.
This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.
Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).
llvm-svn: 304787
We were frequently checking for a list of types and the different types
conveyed no real information. So lump them together explicitly.
llvm-svn: 292095
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
Reid Kleckner