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Allow only disassembling of M-class MSR masks that the assembler knows how to assemble back.

Note: The current code in DecodeMSRMask() rejects the unpredictable A/R MSR mask '0000' with Fail. The code in the patch follows this style and rejects unpredictable M-class MSR masks also with Fail (instead of SoftFail). If SoftFail is preferred in this case then additional changes to ARMInstPrinter (to print non-symbolic masks) and ARMAsmParser (to parse non-symbolic masks) will be needed.

Patch by Petr Pavlu!

llvm-svn: 214505
This commit is contained in:
James Molloy 2014-08-01 12:42:11 +00:00
parent 182f1c73e1
commit 17c114f241
3 changed files with 172 additions and 5 deletions

View File

@ -3974,7 +3974,53 @@ static DecodeStatus DecodeInstSyncBarrierOption(MCInst &Inst, unsigned Val,
static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val, static DecodeStatus DecodeMSRMask(MCInst &Inst, unsigned Val,
uint64_t Address, const void *Decoder) { uint64_t Address, const void *Decoder) {
if (!Val) return MCDisassembler::Fail; uint64_t FeatureBits = ((const MCDisassembler*)Decoder)->getSubtargetInfo()
.getFeatureBits();
if (FeatureBits & ARM::FeatureMClass) {
unsigned ValLow = Val & 0xff;
// Validate the SYSm value first.
switch (ValLow) {
case 0: // apsr
case 1: // iapsr
case 2: // eapsr
case 3: // xpsr
case 5: // ipsr
case 6: // epsr
case 7: // iepsr
case 8: // msp
case 9: // psp
case 16: // primask
case 20: // control
break;
case 17: // basepri
case 18: // basepri_max
case 19: // faultmask
if (!(FeatureBits & ARM::HasV7Ops))
// Values basepri, basepri_max and faultmask are only valid for v7m.
return MCDisassembler::Fail;
break;
default:
return MCDisassembler::Fail;
}
// The ARMv7-M architecture has an additional 2-bit mask value in the MSR
// instruction (bits {11,10}). The mask is used only with apsr, iapsr,
// eapsr and xpsr, it has to be 0b10 in other cases. Bit mask{1} indicates
// if the NZCVQ bits should be moved by the instruction. Bit mask{0}
// indicates the move for the GE{3:0} bits, the mask{0} bit can be set
// only if the processor includes the DSP extension.
if ((FeatureBits & ARM::HasV7Ops) && Inst.getOpcode() == ARM::t2MSR_M) {
unsigned Mask = (Val >> 10) & 3;
if (Mask == 0 || (Mask != 2 && ValLow > 3) ||
(!(FeatureBits & ARM::FeatureDSPThumb2) && Mask == 1))
return MCDisassembler::Fail;
}
} else {
// A/R class
if (Val == 0)
return MCDisassembler::Fail;
}
Inst.addOperand(MCOperand::CreateImm(Val)); Inst.addOperand(MCOperand::CreateImm(Val));
return MCDisassembler::Success; return MCDisassembler::Success;
} }

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@ -0,0 +1,34 @@
# RUN: not llvm-mc -disassemble %s -triple=thumbv7-apple-darwin9 -mcpu cortex-m3 2>&1 | FileCheck %s
#------------------------------------------------------------------------------
# Undefined encodings for mrs
#------------------------------------------------------------------------------
# invalid SYSm
# CHECK: warning: invalid instruction encoding
# CHECK-NEXT: [0xef 0xf3 0x80 0x80]
[0xef 0xf3 0x80 0x80]
#------------------------------------------------------------------------------
# Undefined encodings for msr
#------------------------------------------------------------------------------
# invalid mask = '00'
# CHECK: warning: invalid instruction encoding
# CHECK-NEXT: [0x80 0xf3 0x00 0x80]
[0x80 0xf3 0x00 0x80]
# invalid mask = '11' with SYSm not in {0..3}
# CHECK: warning: invalid instruction encoding
# CHECK-NEXT: [0x80 0xf3 0x04 0x8c]
[0x80 0xf3 0x04 0x8c]
# invalid mask = '01' (Cortex-M3 does not have the DSP extension)
# CHECK: warning: invalid instruction encoding
# CHECK-NEXT: [0x80 0xf3 0x00 0x84]
[0x80 0xf3 0x00 0x84]
# invalid SYSm
# CHECK: warning: invalid instruction encoding
# CHECK-NEXT: [0x80 0xf3 0x80 0x88]
[0x80 0xf3 0x80 0x88]

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@ -1,7 +1,94 @@
# RUN: llvm-mc --disassemble %s -triple=thumbv7-apple-darwin9 -mcpu cortex-m3 | FileCheck %s # RUN: llvm-mc --disassemble %s -triple=thumbv7-apple-darwin9 -mcpu cortex-m4 | FileCheck %s
# CHECK: msr primask, r0 #------------------------------------------------------------------------------
0x80 0xf3 0x10 0x80 # MRS
#------------------------------------------------------------------------------
# CHECK: mrs r0, primask # CHECK: mrs r0, apsr
# CHECK: mrs r0, iapsr
# CHECK: mrs r0, eapsr
# CHECK: mrs r0, xpsr
# CHECK: mrs r0, ipsr
# CHECK: mrs r0, epsr
# CHECK: mrs r0, iepsr
# CHECK: mrs r0, msp
# CHECK: mrs r0, psp
# CHECK: mrs r0, primask
# CHECK: mrs r0, basepri
# CHECK: mrs r0, basepri_max
# CHECK: mrs r0, faultmask
# CHECK: mrs r0, control
0xef 0xf3 0x00 0x80
0xef 0xf3 0x01 0x80
0xef 0xf3 0x02 0x80
0xef 0xf3 0x03 0x80
0xef 0xf3 0x05 0x80
0xef 0xf3 0x06 0x80
0xef 0xf3 0x07 0x80
0xef 0xf3 0x08 0x80
0xef 0xf3 0x09 0x80
0xef 0xf3 0x10 0x80 0xef 0xf3 0x10 0x80
0xef 0xf3 0x11 0x80
0xef 0xf3 0x12 0x80
0xef 0xf3 0x13 0x80
0xef 0xf3 0x14 0x80
#------------------------------------------------------------------------------
# MSR
#------------------------------------------------------------------------------
# CHECK: msr apsr, r0
# CHECK: msr apsr_g, r0
# CHECK: msr apsr_nzcvqg, r0
0x80 0xf3 0x00 0x88
0x80 0xf3 0x00 0x84
0x80 0xf3 0x00 0x8c
# CHECK: msr iapsr, r0
# CHECK: msr iapsr_g, r0
# CHECK: msr iapsr_nzcvqg, r0
0x80 0xf3 0x01 0x88
0x80 0xf3 0x01 0x84
0x80 0xf3 0x01 0x8c
# CHECK: msr eapsr, r0
# CHECK: msr eapsr_g, r0
# CHECK: msr eapsr_nzcvqg, r0
0x80 0xf3 0x02 0x88
0x80 0xf3 0x02 0x84
0x80 0xf3 0x02 0x8c
# CHECK: msr xpsr, r0
# CHECK: msr xpsr_g, r0
# CHECK: msr xpsr_nzcvqg, r0
0x80 0xf3 0x03 0x88
0x80 0xf3 0x03 0x84
0x80 0xf3 0x03 0x8c
# CHECK: msr ipsr, r0
# CHECK: msr epsr, r0
# CHECK: msr iepsr, r0
# CHECK: msr msp, r0
# CHECK: msr psp, r0
# CHECK: msr primask, r0
# CHECK: msr basepri, r0
# CHECK: msr basepri_max, r0
# CHECK: msr faultmask, r0
# CHECK: msr control, r0
0x80 0xf3 0x05 0x88
0x80 0xf3 0x06 0x88
0x80 0xf3 0x07 0x88
0x80 0xf3 0x08 0x88
0x80 0xf3 0x09 0x88
0x80 0xf3 0x10 0x88
0x80 0xf3 0x11 0x88
0x80 0xf3 0x12 0x88
0x80 0xf3 0x13 0x88
0x80 0xf3 0x14 0x88