The asm parser currently selects the wrong encoding for non-conditional Thumb2 branches. However, this exposed a number of situations where the decoder was too permissive in allowing invalid instructions to decode successful. Specify additional fixed bits to close those gaps.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138910 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index 10b17f3..431c67a 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -3243,7 +3243,9 @@
: T2I<oops, iops, itin, opc, asm, pattern> {
let Inst{31-20} = op31_20{11-0};
let Inst{15-14} = op15_14{1-0};
+ let Inst{13} = 0b0;
let Inst{12} = op12{0};
+ let Inst{7-0} = 0;
}
class T2MRS<bits<12> op31_20, bits<2> op15_14, bits<1> op12,
@@ -3276,7 +3278,6 @@
bits<4> Rn;
let Inst{19-16} = Rn;
let Inst{20} = mask{4}; // R Bit
- let Inst{13} = 0b0;
let Inst{11-8} = mask{3-0};
}
diff --git a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index f4ca9ec..0c2abe2 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -2603,17 +2603,17 @@
unsigned pred = fieldFromInstruction32(Insn, 22, 4);
if (pred == 0xE || pred == 0xF) {
- unsigned opc = fieldFromInstruction32(Insn, 4, 2);
+ unsigned opc = fieldFromInstruction32(Insn, 4, 28);
switch (opc) {
default:
return Fail;
- case 0:
+ case 0xf3bf8f4:
Inst.setOpcode(ARM::t2DSB);
break;
- case 1:
+ case 0xf3bf8f5:
Inst.setOpcode(ARM::t2DMB);
break;
- case 2:
+ case 0xf3bf8f6:
Inst.setOpcode(ARM::t2ISB);
return Success;
}