Added soft fail checks for the disassembler when decoding some corner cases of the STRD, STRH, LDRD, LDRH, LDRSH and LDRSB instructions on ARM.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153252 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 102 insertions, 3 deletions

diff --git a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 0f3623985f..0a4d635dcd 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -1536,6 +1536,7 @@ DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
   unsigned pred = fieldFromInstruction32(Insn, 28, 4);
   unsigned W = fieldFromInstruction32(Insn, 21, 1);
   unsigned P = fieldFromInstruction32(Insn, 24, 1);
+  unsigned Rt2 = Rt + 1;
 
   bool writeback = (W == 1) | (P == 0);
 
@@ -1547,7 +1548,86 @@ DecodeAddrMode3Instruction(llvm::MCInst &Inst, unsigned Insn,
     case ARM::LDRD:
     case ARM::LDRD_PRE:
     case ARM::LDRD_POST:
-      if (Rt & 0x1) return MCDisassembler::Fail;
+      if (Rt & 0x1) S = MCDisassembler::SoftFail;
+      break;
+    default:
+      break;
+  }
+  switch (Inst.getOpcode()) {
+    case ARM::STRD:
+    case ARM::STRD_PRE:
+    case ARM::STRD_POST:
+      if (P == 0 && W == 1)
+        S = MCDisassembler::SoftFail;
+      
+      if (writeback && (Rn == 15 || Rn == Rt || Rn == Rt2))
+        S = MCDisassembler::SoftFail;
+      if (type && Rm == 15)
+        S = MCDisassembler::SoftFail;
+      if (Rt2 == 15)
+        S = MCDisassembler::SoftFail;
+      if (!type && fieldFromInstruction32(Insn, 8, 4))
+        S = MCDisassembler::SoftFail;
+      break;
+    case ARM::STRH:
+    case ARM::STRH_PRE:
+    case ARM::STRH_POST:
+      if (Rt == 15)
+        S = MCDisassembler::SoftFail;
+      if (writeback && (Rn == 15 || Rn == Rt))
+        S = MCDisassembler::SoftFail;
+      if (!type && Rm == 15)
+        S = MCDisassembler::SoftFail;
+      break;
+    case ARM::LDRD:
+    case ARM::LDRD_PRE:
+    case ARM::LDRD_POST:
+      if (type && Rn == 15){
+        if (Rt2 == 15)
+          S = MCDisassembler::SoftFail;
+        break;
+      }
+      if (P == 0 && W == 1)
+        S = MCDisassembler::SoftFail;
+      if (!type && (Rt2 == 15 || Rm == 15 || Rm == Rt || Rm == Rt2))
+        S = MCDisassembler::SoftFail;
+      if (!type && writeback && Rn == 15)
+        S = MCDisassembler::SoftFail;
+      if (writeback && (Rn == Rt || Rn == Rt2))
+        S = MCDisassembler::SoftFail;
+      break;
+    case ARM::LDRH:
+    case ARM::LDRH_PRE:
+    case ARM::LDRH_POST:
+      if (type && Rn == 15){
+        if (Rt == 15)
+          S = MCDisassembler::SoftFail;
+        break;
+      }
+      if (Rt == 15)
+        S = MCDisassembler::SoftFail;
+      if (!type && Rm == 15)
+        S = MCDisassembler::SoftFail;
+      if (!type && writeback && (Rn == 15 || Rn == Rt))
+        S = MCDisassembler::SoftFail;
+      break;
+    case ARM::LDRSH:
+    case ARM::LDRSH_PRE:
+    case ARM::LDRSH_POST:
+    case ARM::LDRSB:
+    case ARM::LDRSB_PRE:
+    case ARM::LDRSB_POST:
+      if (type && Rn == 15){
+        if (Rt == 15)
+          S = MCDisassembler::SoftFail;
+        break;
+      }
+      if (type && (Rt == 15 || (writeback && Rn == Rt)))
+        S = MCDisassembler::SoftFail;
+      if (!type && (Rt == 15 || Rm == 15))
+        S = MCDisassembler::SoftFail;
+      if (!type && writeback && (Rn == 15 || Rn == Rt))
+        S = MCDisassembler::SoftFail;
       break;
     default:
       break;
diff --git a/test/MC/Disassembler/ARM/arm-tests.txt b/test/MC/Disassembler/ARM/arm-tests.txt
index 264a78a83e..ce1446b02b 100644
--- a/test/MC/Disassembler/ARM/arm-tests.txt
+++ b/test/MC/Disassembler/ARM/arm-tests.txt
@@ -201,7 +201,7 @@
 0x20 0x51 0x17 0xe6
 
 # CHECK:	strdeq	r2, r3, [r0], -r8
-0xf8 0x24 0x00 0x00
+0xf8 0x20 0x00 0x00
 
 # CHECK:	ldrdeq	r2, r3, [r0], -r12
 0xdc 0x24 0x00 0x00
diff --git a/test/MC/Disassembler/ARM/unpredictable-ADDREXT3-arm.txt b/test/MC/Disassembler/ARM/unpredictable-ADDREXT3-arm.txt
new file mode 100644
index 0000000000..635b66ea43
--- /dev/null
+++ b/test/MC/Disassembler/ARM/unpredictable-ADDREXT3-arm.txt
@@ -0,0 +1,16 @@
+# RUN: llvm-mc --disassemble %s -triple=armv7-linux-gnueabi |& FileCheck %s
+
+# CHECK: potentially undefined
+# CHECK: 0xd1 0xf1 0x5f 0x01
+0xd1 0xf1 0x5f 0x01
+# CHECK: potentially undefined
+# CHECK: 0xf1 0xf1 0x5f 0x01
+0xf1 0xf1 0x5f 0x01
+# CHECK: potentially undefined
+# CHECK: 0xf1 0xf1 0x5f 0x01
+0xf1 0xf1 0x5f 0x01
+# CHECK: potentially undefined
+# CHECK: 0xd1 0xe1 0x4f 0x01
+0xd1 0xe1 0x4f 0x01
+
+
diff --git a/test/MC/Disassembler/ARM/invalid-LDRD-arm.txt b/test/MC/Disassembler/ARM/unpredictable-LDRD-arm.txt
index f8f23ed02b..a8f54f7127 100644
--- a/test/MC/Disassembler/ARM/invalid-LDRD-arm.txt
+++ b/test/MC/Disassembler/ARM/unpredictable-LDRD-arm.txt
@@ -1,4 +1,4 @@
-# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 |& grep {invalid instruction encoding}
+# RUN: llvm-mc --disassemble %s -triple=arm-apple-darwin9 |& FileCheck %s
 
 #  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 
 # -------------------------------------------------------------------------------------------------
@@ -7,4 +7,7 @@
 # 
 # A8.6.68 LDRD (register)
 # if Rt{0} = 1 then UNDEFINED;
+
+# CHECK: potentially undefined
+# CHECK: 0xd0 0x10 0x00 0x00
 0xd0 0x10 0x00 0x00