ARM disassembler was erroneously accepting an invalid RSC instruction.

Added checks for regs which should not be 15.

rdar://problem/9237734

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128945 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp b/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
index 786e001127f3dcb35dcf6245c44a0ae70b314ced..db76c11b7b7de5c23ed17fee5b30f853a6f57976 100644 (file)
--- a/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
@@ -1072,6 +1072,12 @@ static bool DisassembleDPSoRegFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
     if (slice(insn, 7, 7))
       return false;
 
+    // A8.6.3 ADC (register-shifted register)
+    // if d == 15 || n == 15 || m == 15 || s == 15 then UNPREDICTABLE;
+    if (decodeRd(insn) == 15 || decodeRn(insn) == 15 ||
+        decodeRm(insn) == 15 || decodeRs(insn) == 15)
+      return false;
+    
     // Register-controlled shifts: [Rm, Rs, shift].
     MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
                                                        decodeRs(insn))));

diff --git a/test/MC/Disassembler/ARM/invalid-RSC-arm.txt b/test/MC/Disassembler/ARM/invalid-RSC-arm.txt
new file mode 100644 (file)
index 0000000..e7992ae
--- /dev/null
+++ b/test/MC/Disassembler/ARM/invalid-RSC-arm.txt
@@ -0,0 +1,9 @@
+# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 |& grep {invalid instruction encoding}
+
+# Opcode=261 Name=RSCrs Format=ARM_FORMAT_DPSOREGFRM(5)
+#  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 
+# -------------------------------------------------------------------------------------------------
+# | 0: 0: 1: 1| 0: 0: 0: 0| 1: 1: 1: 0| 0: 1: 0: 0| 1: 1: 1: 1| 1: 0: 0: 0| 0: 1: 0: 1| 1: 1: 1: 1|
+# -------------------------------------------------------------------------------------------------
+# if d == 15 || n == 15 || m == 15 || s == 15 then UNPREDICTABLE;
+0x5f 0xf8 0xe4 0x30