[llvm-commits] [llvm] r168960 - in /llvm/trunk: lib/Target/ARM/Disassembler/ARMDisassembler.cpp test/MC/Disassembler/ARM/unpredictable-BFI.txt

[Kevin Enderby]

Author: enderby
Date: Thu Nov 29 17:47:11 2012
New Revision: 168960

URL: http://llvm.org/viewvc/llvm-project?rev=168960&view=rev
Log:
Fixed the arm disassembly of invalid BFI instructions to not build a bad MCInst
which would then cause an assert when printed.  rdar://11437956

Added:
    llvm/trunk/test/MC/Disassembler/ARM/unpredictable-BFI.txt
Modified:
    llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp

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=168960&r1=168959&r2=168960&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (original)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp Thu Nov 29 17:47:11 2012
@@ -1281,7 +1281,13 @@
   unsigned lsb = fieldFromInstruction(Val, 0, 5);
 
   DecodeStatus S = MCDisassembler::Success;
-  if (lsb > msb) Check(S, MCDisassembler::SoftFail);
+  if (lsb > msb) {
+    Check(S, MCDisassembler::SoftFail);
+    // The check above will cause the warning for the "potentially undefined
+    // instruction encoding" but we can't build a bad MCOperand value here
+    // with a lsb > msb or else printing the MCInst will cause a crash.
+    lsb = msb;
+  }
 
   uint32_t msb_mask = 0xFFFFFFFF;
   if (msb != 31) msb_mask = (1U << (msb+1)) - 1;

Added: llvm/trunk/test/MC/Disassembler/ARM/unpredictable-BFI.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Disassembler/ARM/unpredictable-BFI.txt?rev=168960&view=auto
==============================================================================
--- llvm/trunk/test/MC/Disassembler/ARM/unpredictable-BFI.txt (added)
+++ llvm/trunk/test/MC/Disassembler/ARM/unpredictable-BFI.txt Thu Nov 29 17:47:11 2012
@@ -0,0 +1,11 @@
+# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 2>&1 | FileCheck %s
+
+# rdar://11437956
+
+# CHECK: warning: invalid instruction encoding
+# CHECK: 0x90 0x00 0xc0 0xe7
+0x90 0x00 0xc0 0xe7
+
+# CHECK: warning: invalid instruction encoding
+# CHECK: 0x90 0x01 0xc0 0xe7
+0x90 0x01 0xc0 0xe7