[llvm] r183610 - ARM: fix CPS decoding when ambiguous with QADD
Amaury de la Vieuville
amaury.dlv at gmail.com
Sat Jun 8 06:38:52 PDT 2013
Author: amaury.dlv
Date: Sat Jun 8 08:38:52 2013
New Revision: 183610
URL: http://llvm.org/viewvc/llvm-project?rev=183610&view=rev
Log:
ARM: fix CPS decoding when ambiguous with QADD
Handle the case when the disassembler table can't tell
the difference between some encodings of QADD and CPS.
Add some necessary safe guards in CPS decoding as well.
Added:
llvm/trunk/test/MC/Disassembler/ARM/invalid-CPS-arm.txt
Modified:
llvm/trunk/lib/Target/ARM/ARMInstrInfo.td
llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
llvm/trunk/test/MC/Disassembler/ARM/basic-arm-instructions.txt
Modified: llvm/trunk/lib/Target/ARM/ARMInstrInfo.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMInstrInfo.td?rev=183610&r1=183609&r2=183610&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMInstrInfo.td (original)
+++ llvm/trunk/lib/Target/ARM/ARMInstrInfo.td Sat Jun 8 08:38:52 2013
@@ -3279,9 +3279,11 @@ class AAI<bits<8> op27_20, bits<8> op11_
// Saturating add/subtract
+let DecoderMethod = "DecodeQADDInstruction" in
def QADD : AAI<0b00010000, 0b00000101, "qadd",
[(set GPRnopc:$Rd, (int_arm_qadd GPRnopc:$Rm, GPRnopc:$Rn))],
(ins GPRnopc:$Rm, GPRnopc:$Rn), "\t$Rd, $Rm, $Rn">;
+
def QSUB : AAI<0b00010010, 0b00000101, "qsub",
[(set GPRnopc:$Rd, (int_arm_qsub GPRnopc:$Rm, GPRnopc:$Rn))],
(ins GPRnopc:$Rm, GPRnopc:$Rn), "\t$Rd, $Rm, $Rn">;
Modified: llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp?rev=183610&r1=183609&r2=183610&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (original)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp Sat Jun 8 08:38:52 2013
@@ -359,6 +359,8 @@ static DecodeStatus DecodeThumbAddSPReg(
uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbCPS(MCInst &Inst, uint16_t Insn,
uint64_t Address, const void *Decoder);
+static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
+ uint64_t Address, const void *Decoder);
static DecodeStatus DecodeThumbBLXOffset(MCInst &Inst, unsigned Insn,
uint64_t Address, const void *Decoder);
static DecodeStatus DecodeT2AddrModeImm12(MCInst &Inst, unsigned Val,
@@ -1733,6 +1735,29 @@ static DecodeStatus DecodeRFEInstruction
return S;
}
+static DecodeStatus DecodeQADDInstruction(MCInst &Inst, unsigned Insn,
+ uint64_t Address, const void *Decoder) {
+ DecodeStatus S = MCDisassembler::Success;
+
+ unsigned Rd = fieldFromInstruction(Insn, 12, 4);
+ unsigned Rm = fieldFromInstruction(Insn, 0, 4);
+ unsigned Rn = fieldFromInstruction(Insn, 16, 4);
+ unsigned pred = fieldFromInstruction(Insn, 28, 4);
+
+ if (pred == 0xF)
+ return DecodeCPSInstruction(Inst, Insn, Address, Decoder);
+
+ if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rd, Address, Decoder)))
+ return MCDisassembler::Fail;
+ if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rm, Address, Decoder)))
+ return MCDisassembler::Fail;
+ if (!Check(S, DecodeGPRnopcRegisterClass(Inst, Rn, Address, Decoder)))
+ return MCDisassembler::Fail;
+ if (!Check(S, DecodePredicateOperand(Inst, pred, Address, Decoder)))
+ return MCDisassembler::Fail;
+ return S;
+}
+
static DecodeStatus DecodeMemMultipleWritebackInstruction(MCInst &Inst,
unsigned Insn,
uint64_t Address, const void *Decoder) {
@@ -1827,6 +1852,13 @@ static DecodeStatus DecodeCPSInstruction
DecodeStatus S = MCDisassembler::Success;
+ // This decoder is called from multiple location that do not check
+ // the full encoding is valid before they do.
+ if (fieldFromInstruction(Insn, 5, 1) != 0 ||
+ fieldFromInstruction(Insn, 16, 1) != 0 ||
+ fieldFromInstruction(Insn, 20, 8) != 0x10)
+ return MCDisassembler::Fail;
+
// imod == '01' --> UNPREDICTABLE
// NOTE: Even though this is technically UNPREDICTABLE, we choose to
// return failure here. The '01' imod value is unprintable, so there's
Modified: llvm/trunk/test/MC/Disassembler/ARM/basic-arm-instructions.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Disassembler/ARM/basic-arm-instructions.txt?rev=183610&r1=183609&r2=183610&view=diff
==============================================================================
--- llvm/trunk/test/MC/Disassembler/ARM/basic-arm-instructions.txt (original)
+++ llvm/trunk/test/MC/Disassembler/ARM/basic-arm-instructions.txt Sat Jun 8 08:38:52 2013
@@ -454,10 +454,14 @@
# CHECK: cpsie aif
# CHECK: cps #15
# CHECK: cpsid if, #10
+# CHECK: cpsid af, #17
+# CHECK: cpsie f, #26
0xc0 0x01 0x08 0xf1
0x0f 0x00 0x02 0xf1
0xca 0x00 0x0e 0xf1
+0x51 0x01 0x0e 0xf1
+0x5a 0x00 0x0a 0xf1
#------------------------------------------------------------------------------
Added: llvm/trunk/test/MC/Disassembler/ARM/invalid-CPS-arm.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Disassembler/ARM/invalid-CPS-arm.txt?rev=183610&view=auto
==============================================================================
--- llvm/trunk/test/MC/Disassembler/ARM/invalid-CPS-arm.txt (added)
+++ llvm/trunk/test/MC/Disassembler/ARM/invalid-CPS-arm.txt Sat Jun 8 08:38:52 2013
@@ -0,0 +1,9 @@
+# CPS: various encodings that are ambiguous with other instructions
+
+# RUN: echo "0x9f 0xff 0x4e 0xf1" | llvm-mc -triple=armv7 -disassemble 2>&1 | FileCheck %s
+# RUN: echo "0x80 0x80 0x2c 0xf1" | llvm-mc -triple=armv7 -disassemble 2>&1 | FileCheck %s
+# RUN: echo "0xce 0x3f 0x28 0xf1" | llvm-mc -triple=armv7 -disassemble 2>&1 | FileCheck %s
+# RUN: echo "0x80 0x00 0x20 0xf1" | llvm-mc -triple=armv7 -disassemble 2>&1 | FileCheck %s
+# RUN: echo "0xa0 0x00 0x00 0xf1" | llvm-mc -triple=armv7 -disassemble 2>&1 | FileCheck %s
+
+# CHECK: invalid instruction encoding
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