PPC: Enable unaligned access and clean up the use of UNALIGNED_ACCESSES

src/regexp/ppc/regexp-macro-assembler-ppc.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_PPC
 
 #include "src/regexp/ppc/regexp-macro-assembler-ppc.h"
 
 #include "src/base/bits.h"
 #include "src/code-stubs.h"
@@ skipping 1251 matching lines @@
 void RegExpMacroAssemblerPPC::CheckStackLimit() {
   ExternalReference stack_limit =
       ExternalReference::address_of_regexp_stack_limit(isolate());
   __ mov(r3, Operand(stack_limit));
   __ LoadP(r3, MemOperand(r3));
   __ cmpl(backtrack_stackpointer(), r3);
   SafeCall(&stack_overflow_label_, le);
 }
 
 
-bool RegExpMacroAssemblerPPC::CanReadUnaligned() {
-  return CpuFeatures::IsSupported(UNALIGNED_ACCESSES) && !slow_safe();
-}
-
-
 void RegExpMacroAssemblerPPC::LoadCurrentCharacterUnchecked(int cp_offset,
                                                             int characters) {
   Register offset = current_input_offset();
   if (cp_offset != 0) {
     // r25 is not being used to store the capture start index at this point.
     __ addi(r25, current_input_offset(), Operand(cp_offset * char_size()));
     offset = r25;
   }
   // The lwz, stw, lhz, sth instructions can do unaligned accesses, if the CPU
   // and the operating system running on the target allow it.
   // We assume we don't want to do unaligned loads on PPC, so this function
   // must only be used to load a single character at a time.
 
-  DCHECK(characters == 1);
   __ add(current_character(), end_of_input_address(), offset);
+#if V8_TARGET_LITTLE_ENDIAN
   if (mode_ == LATIN1) {
-    __ lbz(current_character(), MemOperand(current_character()));
+    if (characters == 4) {
+      __ lwz(current_character(), MemOperand(current_character()));
+    } else if (characters == 2) {
+      __ lhz(current_character(), MemOperand(current_character()));
+    } else {
+      DCHECK(characters == 1);
+      __ lbz(current_character(), MemOperand(current_character()));
+    }
   } else {
     DCHECK(mode_ == UC16);
-    __ lhz(current_character(), MemOperand(current_character()));
+    if (characters == 2) {
+      __ lwz(current_character(), MemOperand(current_character()));
+    } else {
+      DCHECK(characters == 1);
+      __ lhz(current_character(), MemOperand(current_character()));
+    }
   }
+#else
+  if (mode_ == LATIN1) {
+    if (characters == 4) {
+      __ lwbrx(current_character(), MemOperand(r0, current_character()));
+    } else if (characters == 2) {
+      __ lhbrx(current_character(), MemOperand(r0, current_character()));
+    } else {
+      DCHECK(characters == 1);
+      __ lbz(current_character(), MemOperand(current_character()));
+    }
+  } else {
+    DCHECK(mode_ == UC16);
+    if (characters == 2) {
+      __ lwz(current_character(), MemOperand(current_character()));
+      __ rlwinm(current_character(), current_character(), 16, 0, 31);
+    } else {
+      DCHECK(characters == 1);
+      __ lhz(current_character(), MemOperand(current_character()));
+    }
+  }
+#endif
 }
 
 
 #undef __
 
 #endif  // V8_INTERPRETED_REGEXP
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_PPC