Fix issues with Arm's use of embedded constant pools

src/arm/assembler-arm.cc

Index: src/arm/assembler-arm.cc
diff --git a/src/arm/assembler-arm.cc b/src/arm/assembler-arm.cc
index ed8664a9c5f32f10ddc131ad8973e2b79cc37347..eb303d1c2449cc63a4d5a9a3b0468153f8e7efb1 100644
--- a/src/arm/assembler-arm.cc
+++ b/src/arm/assembler-arm.cc
@@ -494,12 +494,21 @@ void Assembler::GetCode(CodeDesc* desc) {
 
 void Assembler::Align(int m) {
   DCHECK(m >= 4 && base::bits::IsPowerOfTwo32(m));
+  DCHECK((pc_offset() & (kInstrSize - 1)) == 0);
   while ((pc_offset() & (m - 1)) != 0) {
     nop();
   }
 }
 
 
+void Assembler::DataAlign(int m) {
+  DCHECK(m >= 2 && base::bits::IsPowerOfTwo32(m));
+  while ((pc_offset() & (m - 1)) != 0) {
+    db(0);
+  }
+}
+
+
 void Assembler::CodeTargetAlign() {
   // Preferred alignment of jump targets on some ARM chips.
   Align(8);