[PATCH] ARM: thumb byte & halfword stores cannot use PC as dest register

[Amaury de la Vieuville]

amaury.dlv added you to the CC list for the revision "ARM: thumb byte & halfword stores cannot use PC as dest register".

http://llvm-reviews.chandlerc.com/D972

Files:
  lib/Target/ARM/Disassembler/ARMDisassembler.cpp
  test/MC/Disassembler/ARM/invalid-STR-thumb.txt

Index: lib/Target/ARM/Disassembler/ARMDisassembler.cpp
===================================================================
--- lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -3164,6 +3164,16 @@
   unsigned Rm = fieldFromInstruction(Val, 2, 4);
   unsigned imm = fieldFromInstruction(Val, 0, 2);
 
+  switch (Inst.getOpcode()) {
+  case ARM::t2STRHs:
+  case ARM::t2STRBs:
+  case ARM::t2STRs:
+    if (Rn == 15)
+      return MCDisassembler::Fail;
+  default:
+    break;
+  }
+
   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
     return MCDisassembler::Fail;
   if (!Check(S, DecoderGPRRegisterClass(Inst, Rm, Address, Decoder)))
@@ -3292,6 +3302,20 @@
   unsigned Rn = fieldFromInstruction(Val, 9, 4);
   unsigned imm = fieldFromInstruction(Val, 0, 9);
 
+  switch (Inst.getOpcode()) {
+  case ARM::t2STRT:
+  case ARM::t2STRBT:
+  case ARM::t2STRHT:
+  case ARM::t2STRi8:
+  case ARM::t2STRHi8:
+  case ARM::t2STRBi8:
+    if (Rn == 15)
+      return MCDisassembler::Fail;
+    break;
+  default:
+    break;
+  }
+
   // Some instructions always use an additive offset.
   switch (Inst.getOpcode()) {
     case ARM::t2LDRT:
@@ -3353,6 +3377,16 @@
   unsigned Rn = fieldFromInstruction(Val, 13, 4);
   unsigned imm = fieldFromInstruction(Val, 0, 12);
 
+  switch (Inst.getOpcode()) {
+  case ARM::t2STRi12:
+  case ARM::t2STRBi12:
+  case ARM::t2STRHi12:
+    if (Rn == 15)
+      return MCDisassembler::Fail;
+  default:
+    break;
+  }
+
   if (!Check(S, DecodeGPRRegisterClass(Inst, Rn, Address, Decoder)))
     return MCDisassembler::Fail;
   Inst.addOperand(MCOperand::CreateImm(imm));
Index: test/MC/Disassembler/ARM/invalid-STR-thumb.txt
===================================================================
--- /dev/null
+++ test/MC/Disassembler/ARM/invalid-STR-thumb.txt
@@ -0,0 +1,25 @@
+# invalid t2STRB_PRE Rn=PC
+# RUN: echo "0x0f 0xf8 0x5f 0x0f" | llvm-mc -triple=thumbv7 -disassemble 2>&1 | FileCheck %s
+
+# invalid t2STRHi12 Rn=PC
+# RUN: echo "0xaf 0xf8 0xff 0xef" | llvm-mc -triple=thumbv7 -disassemble 2>&1 | FileCheck %s
+
+# invalid t2STRBi12 Rn=PC
+# RUN: echo "0xcf 0xf8 0xff 0xff" | llvm-mc -triple=thumbv7 -disassemble 2>&1 | FileCheck %s
+
+# invalid t2STRBi8 Rn=PC
+# RUN: echo "0x0f 0xf8 0x00 0x09" | llvm-mc -triple=thumbv7 -disassemble 2>&1 | FileCheck %s
+
+# invalid t2STRBT Rn=PC
+# RUN: echo "0x0f 0xf8 0x00 0x0e" | llvm-mc -triple=thumbv7 -disassemble 2>&1 | FileCheck %s
+
+# invalid t2STRi8 Rn=PC
+# RUN: echo "0x4f 0xf8 0x00 0x0c" | llvm-mc -triple=thumbv7 -disassemble 2>&1 | FileCheck %s
+
+# invalid t2STRHi8 Rn=PC
+# RUN: echo "0x2f 0xf8 0x00 0x0c" | llvm-mc -triple=thumbv7 -disassemble 2>&1 | FileCheck %s
+
+# invalid t2STRB_PRE Rn=PC
+# RUN: echo "0x0f 0xf8 0x5f 0x0f" | llvm-mc -triple=thumbv7 -disassemble 2>&1 | FileCheck %s
+
+# CHECK: invalid instruction encoding
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