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Update the X86 disassembler to use xacquire and xrelease when appropriate. 

This is a bit tricky as the xacquire and xrelease hints use the same bytes,
0xf2 and 0xf3, as the repne and rep prefixes.

Fortunately llvm has different llvm MCInst Opcode enums for rep/xrelease
and repne/xacquire. So to make this work a boolean was added the
InternalInstruction struct as part of the Prefix state which is set with the
added logic in readPrefixes() when decoding an instruction to determine
if these prefix bytes are to be disassembled as xacquire or xrelease.  Then
we let the matcher pick the normal prefix instructionID and we change the
Opcode after that when it is set into the MCInst being created.

rdar://11019859

llvm-svn: 184490
This commit is contained in:
Kevin Enderby 2013-06-20 22:32:18 +00:00
parent 40238f0451
commit 35fd79237f
4 changed files with 61 additions and 1 deletions
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9
llvm/lib/Target/X86/Disassembler/X86Disassembler.cpp
View File

@ -683,6 +683,15 @@ static bool translateInstruction(MCInst &mcInst,
}
mcInst.setOpcode(insn.instructionID);
// If when reading the prefix bytes we determined the overlapping 0xf2 or 0xf3
// prefix bytes should be disassembled as xrelease and xacquire then set the
// opcode to those instead of the rep and repne opcodes.
if (insn.xAcquireRelease) {
if(mcInst.getOpcode() == X86::REP_PREFIX)
mcInst.setOpcode(X86::XRELEASE_PREFIX);
else if(mcInst.getOpcode() == X86::REPNE_PREFIX)
mcInst.setOpcode(X86::XACQUIRE_PREFIX);
}
int index;

21
llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.c
View File

@ -328,6 +328,27 @@ static int readPrefixes(struct InternalInstruction* insn) {
break;
if (lookAtByte(insn, &nextByte))
return -1;
/*
* If the byte is 0xf2 or 0xf3, and any of the following conditions are
* met:
* - it is followed by a LOCK (0xf0) prefix
* - it is followed by an xchg instruction
* then it should be disassembled as a xacquire/xrelease not repne/rep.
*/
if ((byte == 0xf2 || byte == 0xf3) &&
((nextByte == 0xf0) |
((nextByte & 0xfe) == 0x86 || (nextByte & 0xf8) == 0x90)))
insn->xAcquireRelease = TRUE;
/*
* Also if the byte is 0xf3, and the following condition is met:
* - it is followed by a "mov mem, reg" (opcode 0x88/0x89) or
* "mov mem, imm" (opcode 0xc6/0xc7) instructions.
* then it should be disassembled as an xrelease not rep.
*/
if (byte == 0xf3 &&
(nextByte == 0x88 || nextByte == 0x89 ||
nextByte == 0xc6 || nextByte == 0xc7))
insn->xAcquireRelease = TRUE;
if (insn->mode == MODE_64BIT && (nextByte & 0xf0) == 0x40) {
if (consumeByte(insn, &nextByte))
return -1;

2
llvm/lib/Target/X86/Disassembler/X86DisassemblerDecoder.h
View File

@ -457,6 +457,8 @@ struct InternalInstruction {
uint64_t necessaryPrefixLocation;
/* The segment override type */
SegmentOverride segmentOverride;
/* 1 if the prefix byte, 0xf2 or 0xf3 is xacquire or xrelease */
BOOL xAcquireRelease;
/* Sizes of various critical pieces of data, in bytes */
uint8_t registerSize;

30
llvm/test/MC/Disassembler/X86/simple-tests.txt
View File

@ -764,7 +764,35 @@
# CHECK: repne
# CHECK-NEXT: movb $0, (%rax)
0xf2 0xc6 0x0 0x0
# CHECK: rep
# rdar://11019859 Support 2013 Haswell RTM instructions and HLE prefixes
# CHECK: xrelease
# CHECK-NEXT: lock
# CHECK-NEXT: incl (%rax)
0xf3 0xf0 0xff 0x00
# CHECK: xrelease
# CHECK-NEXT: xchgl %ebx, %eax
0xf3 0x93
# CHECK: xrelease
# CHECK-NEXT: xchgl %ebx, (%rax)
0xf3 0x87 0x18
# CHECK: xrelease
# CHECK-NEXT: movb %al, (%rbx)
0xf3 0x88 0x03
# CHECK: xrelease
# CHECK-NEXT: movl %eax, (%rbx)
0xf3 0x89 0x03
# CHECK: xrelease
# CHECK-NEXT: movb $1, (%rbx)
0xf3 0xc6 0x03 0x01
# CHECK: xrelease
# CHECK-NEXT: movl $1, (%rbx)
0xf3 0xc7 0x03 0x01 0x00 0x00 0x00
# CHECK: xacquire
# CHECK-NEXT: xchgl %ebx, %eax
0xf2 0x93
# CHECK: xacquire
# CHECK-NEXT: xchgl %ebx, (%rax)
0xf2 0x87 0x18