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A8.6.393

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The ARM disassembler should reject invalid (type, align) encodings as invalid instructions.

So, instead of:
Opcode=1641 Name=VST2b32_UPD Format=ARM_FORMAT_NLdSt(30)
 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0 
-------------------------------------------------------------------------------------------------
| 1: 1: 1: 1| 0: 1: 0: 0| 0: 0: 0: 0| 0: 0: 1: 1| 0: 0: 0: 0| 1: 0: 0: 1| 1: 0: 1: 1| 0: 0: 1: 1|
-------------------------------------------------------------------------------------------------

	vst2.32	{d0, d2}, [r3, :256], r3

we now have:
Opcode=1641 Name=VST2b32_UPD Format=ARM_FORMAT_NLdSt(30)
 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10  9  8  7  6  5  4  3  2  1  0 
-------------------------------------------------------------------------------------------------
| 1: 1: 1: 1| 0: 1: 0: 0| 0: 0: 0: 0| 0: 0: 1: 1| 0: 0: 0: 0| 1: 0: 0: 1| 1: 0: 1: 1| 0: 0: 1: 1|
-------------------------------------------------------------------------------------------------

mc-input.txt:1:1: warning: invalid instruction encoding
0xb3 0x9 0x3 0xf4
^


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129033 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Johnny Chen 2011-04-06 22:14:48 +00:00
parent 01ccab4012
commit d8b4c4d74f
2 changed files with 60 additions and 28 deletions
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59
lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
View File

@ -2497,10 +2497,6 @@ static bool DisassembleNLdSt(MCInst &MI, unsigned Opcode, uint32_t insn,
// 0 represents standard alignment, i.e., unaligned data access.
unsigned alignment = 0;
if (Name.find("LN") != std::string::npos) {
// To one lane instructions.
// See, for example, 8.6.317 VLD4 (single 4-element structure to one lane).
unsigned elem = 0; // legal values: {1, 2, 3, 4}
if (Name.startswith("VST1") || Name.startswith("VLD1"))
elem = 1;
@ -2514,6 +2510,10 @@ static bool DisassembleNLdSt(MCInst &MI, unsigned Opcode, uint32_t insn,
if (Name.startswith("VST4") || Name.startswith("VLD4"))
elem = 4;
if (Name.find("LN") != std::string::npos) {
// To one lane instructions.
// See, for example, 8.6.317 VLD4 (single 4-element structure to one lane).
// Utility function takes number of elements, size, and index_align.
if (!Align4OneLaneInst(elem,
slice(insn, 11, 10),
@ -2533,7 +2533,8 @@ static bool DisassembleNLdSt(MCInst &MI, unsigned Opcode, uint32_t insn,
// See, for example, A8.6.316 VLD4 (multiple 4-element structures).
// Inst{5-4} encodes alignment.
switch (slice(insn, 5, 4)) {
unsigned align = slice(insn, 5, 4);
switch (align) {
default:
break;
case 1:
@ -2544,22 +2545,42 @@ static bool DisassembleNLdSt(MCInst &MI, unsigned Opcode, uint32_t insn,
alignment = 256; break;
}
// n == 2 && type == 0b1001 -> DblSpaced = true
if (Name.startswith("VST2") || Name.startswith("VLD2"))
DblSpaced = slice(insn, 11, 8) == 9;
// n == 3 && type == 0b0101 -> DblSpaced = true
if (Name.startswith("VST3") || Name.startswith("VLD3")) {
// A8.6.313 & A8.6.395
if (slice(insn, 7, 6) == 3 && slice(insn, 5, 5) == 1)
unsigned type = slice(insn, 11, 8);
// Reject UNDEFINED instructions based on type and align.
// Plus set DblSpaced flag where appropriate.
switch (elem) {
default:
break;
case 1:
// n == 1
// A8.6.307 & A8.6.391
if ((type == 7 && slice(align, 1, 1) == 1) ||
(type == 10 && align == 3) ||
(type == 6 && slice(align, 1, 1) == 1))
return false;
DblSpaced = slice(insn, 11, 8) == 5;
}
break;
case 2:
// n == 2 && type == 0b1001 -> DblSpaced = true
// A8.6.310 & A8.6.393
if ((type == 8 || type == 9) && align == 3)
return false;
DblSpaced = (type == 9);
break;
case 3:
// n == 3 && type == 0b0101 -> DblSpaced = true
// A8.6.313 & A8.6.395
if (slice(insn, 7, 6) == 3 || slice(align, 1, 1) == 1)
return false;
DblSpaced = (type == 5);
break;
case 4:
// n == 4 && type == 0b0001 -> DblSpaced = true
if (Name.startswith("VST4") || Name.startswith("VLD4"))
DblSpaced = slice(insn, 11, 8) == 1;
// A8.6.316 & A8.6.397
if (slice(insn, 7, 6) == 3)
return false;
DblSpaced = (type == 1);
break;
}
}
return DisassembleNLdSt0(MI, Opcode, insn, NumOps, NumOpsAdded,
slice(insn, 21, 21) == 0, DblSpaced, alignment/8, B);

11
test/MC/Disassembler/ARM/invalid-VST2b32_UPD-arm.txt Normal file
View File

@ -0,0 +1,11 @@
# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 |& grep {invalid instruction encoding}
# Opcode=1641 Name=VST2b32_UPD Format=ARM_FORMAT_NLdSt(30)
# 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
# -------------------------------------------------------------------------------------------------
# | 1: 1: 1: 1| 0: 1: 0: 0| 0: 0: 0: 0| 0: 0: 1: 1| 0: 0: 0: 0| 1: 0: 0: 1| 1: 0: 1: 1| 0: 0: 1: 1|
# -------------------------------------------------------------------------------------------------
#
# A8.6.393 VST2 (multiple 2-element structures)
# type == '1001' and align == '11' ==> UNDEFINED
0xb3 0x9 0x3 0xf4