Sanity check MSRi for invalid mask values and reject it as invalid.

rdar://problem/9246844

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129050 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp b/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
index 48a748b..bc0ba92 100644 (file)
--- a/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
@@ -836,6 +836,11 @@ static bool DisassembleBrFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
   // MSRi take a mask, followed by one so_imm operand. The mask contains the
   // R Bit in bit 4, and the special register fields in bits 3-0.
   if (Opcode == ARM::MSRi) {
+    // A5.2.11 MSR (immediate), and hints & B6.1.6 MSR (immediate)
+    // The hints instructions have more specific encodings, so if mask == 0,
+    // we should reject this as an invalid instruction.
+    if (slice(insn, 19, 16) == 0)
+      return false;
     MI.addOperand(MCOperand::CreateImm(slice(insn, 22, 22) << 4 /* R Bit */ |
                                        slice(insn, 19, 16) /* Special Reg */ ));
     // SOImm is 4-bit rotate amount in bits 11-8 with 8-bit imm in bits 7-0.

diff --git a/test/MC/Disassembler/ARM/invalid-MSRi-arm.txt b/test/MC/Disassembler/ARM/invalid-MSRi-arm.txt
new file mode 100644 (file)
index 0000000..e9d5deb
--- /dev/null
+++ b/test/MC/Disassembler/ARM/invalid-MSRi-arm.txt
@@ -0,0 +1,12 @@
+# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 |& grep {invalid instruction encoding}
+
+# Opcode=206 Name=MSRi Format=ARM_FORMAT_BRFRM(2)
+#  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: 0: 0| 0: 0: 1: 1| 0: 0: 1: 0| 0: 0: 0: 0| 1: 1: 1: 1| 0: 0: 0: 1| 1: 0: 1: 0| 0: 1: 1: 1|
+# -------------------------------------------------------------------------------------------------
+#
+# A5.2.11 MSR (immediate), and hints & B6.1.6 MSR (immediate)
+# The hints instructions have more specific encodings, so if mask == 0,
+# we should reject this as an invalid instruction.
+0xa7 0xf1 0x20 0x3