[llvm-commits] [llvm] r139432 - in /llvm/trunk: lib/Target/ARM/Disassembler/ARMDisassembler.cpp test/MC/Disassembler/ARM/invalid-LDM-thumb.txt

[Owen Anderson]

Author: resistor
Date: Fri Sep  9 18:13:33 2011
New Revision: 139432

URL: http://llvm.org/viewvc/llvm-project?rev=139432&view=rev
Log:
LDM writeback is not allowed if Rn is in the target register list.

Added:
    llvm/trunk/test/MC/Disassembler/ARM/invalid-LDM-thumb.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=139432&r1=139431&r2=139432&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp (original)
+++ llvm/trunk/lib/Target/ARM/Disassembler/ARMDisassembler.cpp Fri Sep  9 18:13:33 2011
@@ -918,12 +918,31 @@
                                  uint64_t Address, const void *Decoder) {
   DecodeStatus S = MCDisassembler::Success;
 
+  bool writebackLoad = false;
+  unsigned writebackReg = 0;
+  switch (Inst.getOpcode()) {
+    default:
+      break;
+    case ARM::LDMIA_UPD:
+    case ARM::LDMDB_UPD:
+    case ARM::LDMIB_UPD:
+    case ARM::LDMDA_UPD:
+    case ARM::t2LDMIA_UPD:
+    case ARM::t2LDMDB_UPD:
+      writebackLoad = true;
+      writebackReg = Inst.getOperand(0).getReg();
+      break;
+  }
+
   // Empty register lists are not allowed.
   if (CountPopulation_32(Val) == 0) return MCDisassembler::Fail;
   for (unsigned i = 0; i < 16; ++i) {
     if (Val & (1 << i)) {
       if (!Check(S, DecodeGPRRegisterClass(Inst, i, Address, Decoder)))
         return MCDisassembler::Fail;
+      // Writeback not allowed if Rn is in the target list.
+      if (writebackLoad && writebackReg == Inst.end()[-1].getReg())
+        Check(S, MCDisassembler::SoftFail);
     }
   }
 

Added: llvm/trunk/test/MC/Disassembler/ARM/invalid-LDM-thumb.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Disassembler/ARM/invalid-LDM-thumb.txt?rev=139432&view=auto
==============================================================================
--- llvm/trunk/test/MC/Disassembler/ARM/invalid-LDM-thumb.txt (added)
+++ llvm/trunk/test/MC/Disassembler/ARM/invalid-LDM-thumb.txt Fri Sep  9 18:13:33 2011
@@ -0,0 +1,5 @@
+# RUN: llvm-mc --disassemble %s -triple=thumbv7-apple-darwin9 |& grep {potentially undefined instruction encoding}
+
+# Writeback is not allowed is Rn is in the target register list.
+
+0xb4 0xe8 0x34 0x04