[arm] Clean up the use of UNALIGNED_ACCESSES.

src/arm/simulator-arm.cc

Index: src/arm/simulator-arm.cc
diff --git a/src/arm/simulator-arm.cc b/src/arm/simulator-arm.cc
index afe31db95063ec4c214049dbdb52bda4717ecbb7..ab416d724a73f1527660ad5f0982c013b8f23b7a 100644
--- a/src/arm/simulator-arm.cc
+++ b/src/arm/simulator-arm.cc
@@ -1107,98 +1107,51 @@ void Simulator::TrashCallerSaveRegisters() {
 }
 
 
-// Some Operating Systems allow unaligned access on ARMv7 targets. We
-// assume that unaligned accesses are not allowed unless the v8 build system
-// defines the CAN_USE_UNALIGNED_ACCESSES macro to be non-zero.
-// The following statements below describes the behavior of the ARM CPUs
-// that don't support unaligned access.
-// Some ARM platforms raise an interrupt on detecting unaligned access.
-// On others it does a funky rotation thing.  For now we
-// simply disallow unaligned reads.  Note that simulator runs have the runtime
-// system running directly on the host system and only generated code is
-// executed in the simulator.  Since the host is typically IA32 we will not
-// get the correct ARM-like behaviour on unaligned accesses for those ARM
-// targets that don't support unaligned loads and stores.
-
-
 int Simulator::ReadW(int32_t addr, Instruction* instr) {
-  if (FLAG_enable_unaligned_accesses || (addr & 3) == 0) {
-    intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
-    return *ptr;
-  } else {
-    PrintF("Unaligned read at 0x%08x, pc=0x%08" V8PRIxPTR "\n",
-           addr,
-           reinterpret_cast<intptr_t>(instr));
-    UNIMPLEMENTED();
-    return 0;
-  }
+  // All supported ARM targets allow unaligned accesses, so we don't need to
+  // check the alignment here.
+  intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
+  return *ptr;
 }
 
 
 void Simulator::WriteW(int32_t addr, int value, Instruction* instr) {
-  if (FLAG_enable_unaligned_accesses || (addr & 3) == 0) {
-    intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
-    *ptr = value;
-  } else {
-    PrintF("Unaligned write at 0x%08x, pc=0x%08" V8PRIxPTR "\n",
-           addr,
-           reinterpret_cast<intptr_t>(instr));
-    UNIMPLEMENTED();
-  }
+  // All supported ARM targets allow unaligned accesses, so we don't need to
+  // check the alignment here.
+  intptr_t* ptr = reinterpret_cast<intptr_t*>(addr);
+  *ptr = value;
 }
 
 
 uint16_t Simulator::ReadHU(int32_t addr, Instruction* instr) {
-  if (FLAG_enable_unaligned_accesses || (addr & 1) == 0) {
-    uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
-    return *ptr;
-  } else {
-    PrintF("Unaligned unsigned halfword read at 0x%08x, pc=0x%08"
-           V8PRIxPTR "\n",
-           addr,
-           reinterpret_cast<intptr_t>(instr));
-    UNIMPLEMENTED();
-    return 0;
-  }
+  // All supported ARM targets allow unaligned accesses, so we don't need to
+  // check the alignment here.
+  uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
+  return *ptr;
 }
 
 
 int16_t Simulator::ReadH(int32_t addr, Instruction* instr) {
-  if (FLAG_enable_unaligned_accesses || (addr & 1) == 0) {
-    int16_t* ptr = reinterpret_cast<int16_t*>(addr);
-    return *ptr;
-  } else {
-    PrintF("Unaligned signed halfword read at 0x%08x\n", addr);
-    UNIMPLEMENTED();
-    return 0;
-  }
+  // All supported ARM targets allow unaligned accesses, so we don't need to
+  // check the alignment here.
+  int16_t* ptr = reinterpret_cast<int16_t*>(addr);
+  return *ptr;
 }
 
 
 void Simulator::WriteH(int32_t addr, uint16_t value, Instruction* instr) {
-  if (FLAG_enable_unaligned_accesses || (addr & 1) == 0) {
-    uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
-    *ptr = value;
-  } else {
-    PrintF("Unaligned unsigned halfword write at 0x%08x, pc=0x%08"
-           V8PRIxPTR "\n",
-           addr,
-           reinterpret_cast<intptr_t>(instr));
-    UNIMPLEMENTED();
-  }
+  // All supported ARM targets allow unaligned accesses, so we don't need to
+  // check the alignment here.
+  uint16_t* ptr = reinterpret_cast<uint16_t*>(addr);
+  *ptr = value;
 }
 
 
 void Simulator::WriteH(int32_t addr, int16_t value, Instruction* instr) {
-  if (FLAG_enable_unaligned_accesses || (addr & 1) == 0) {
-    int16_t* ptr = reinterpret_cast<int16_t*>(addr);
-    *ptr = value;
-  } else {
-    PrintF("Unaligned halfword write at 0x%08x, pc=0x%08" V8PRIxPTR "\n",
-           addr,
-           reinterpret_cast<intptr_t>(instr));
-    UNIMPLEMENTED();
-  }
+  // All supported ARM targets allow unaligned accesses, so we don't need to
+  // check the alignment here.
+  int16_t* ptr = reinterpret_cast<int16_t*>(addr);
+  *ptr = value;
 }
 
 
@@ -1227,26 +1180,19 @@ void Simulator::WriteB(int32_t addr, int8_t value) {
 
 
 int32_t* Simulator::ReadDW(int32_t addr) {
-  if (FLAG_enable_unaligned_accesses || (addr & 3) == 0) {
-    int32_t* ptr = reinterpret_cast<int32_t*>(addr);
-    return ptr;
-  } else {
-    PrintF("Unaligned read at 0x%08x\n", addr);
-    UNIMPLEMENTED();
-    return 0;
-  }
+  // All supported ARM targets allow unaligned accesses, so we don't need to
+  // check the alignment here.
+  int32_t* ptr = reinterpret_cast<int32_t*>(addr);
+  return ptr;
 }
 
 
 void Simulator::WriteDW(int32_t addr, int32_t value1, int32_t value2) {
-  if (FLAG_enable_unaligned_accesses || (addr & 3) == 0) {
-    int32_t* ptr = reinterpret_cast<int32_t*>(addr);
-    *ptr++ = value1;
-    *ptr = value2;
-  } else {
-    PrintF("Unaligned write at 0x%08x\n", addr);
-    UNIMPLEMENTED();
-  }
+  // All supported ARM targets allow unaligned accesses, so we don't need to
+  // check the alignment here.
+  int32_t* ptr = reinterpret_cast<int32_t*>(addr);
+  *ptr++ = value1;
+  *ptr = value2;
 }