[llvm-commits] [llvm] r128192 - /llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp

[Johnny Chen]

Author: johnny
Date: Wed Mar 23 21:24:36 2011
New Revision: 128192

URL: http://llvm.org/viewvc/llvm-project?rev=128192&view=rev
Log:
CPS3p: Let's reject impossible imod values by returning false from the DisassembleMiscFrm() function.

Fixed rdar://problem/9179416 ARM disassembler crash: "Unknown imod operand" (fuzz testing)

Opcode=98 Name=CPS3p Format=ARM_FORMAT_MISCFRM(26)
 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 
-------------------------------------------------------------------------------------------------
| 1: 1: 1: 1| 0: 0: 0: 1| 0: 0: 0: 0| 0: 0: 1: 0| 0: 0: 0: 1| 1: 1: 0: 0| 1: 0: 0: 1| 0: 0: 1: 1|
-------------------------------------------------------------------------------------------------

Before:
	cpsUnknown imod operand
UNREACHABLE executed at /Volumes/data/lldb/llvm/lib/Target/ARM/InstPrinter/../ARMBaseInfo.h:123!

After:
/Volumes/data/Radar/9179416/mc-input-arm.txt:1:1: warning: invalid instruction encoding
0x93 0x1c 0x2 0xf1
^

Modified:
    llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp

Modified: llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp?rev=128192&r1=128191&r2=128192&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp (original)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassemblerCore.cpp Wed Mar 23 21:24:36 2011
@@ -2945,6 +2945,9 @@
   // no current handling of optional arguments. Fix here when a better handling
   // of optional arguments is implemented.
   if (Opcode == ARM::CPS3p) {
+    // Let's reject impossible imod values by returning false.
+    if (slice(insn, 19, 18) == 0 || slice(insn, 19, 18) == 1)
+      return false;
     MI.addOperand(MCOperand::CreateImm(slice(insn, 19, 18))); // imod
     MI.addOperand(MCOperand::CreateImm(slice(insn, 8, 6)));   // iflags
     MI.addOperand(MCOperand::CreateImm(slice(insn, 4, 0)));   // mode