S390X: Prevent upper 32bit corruption in 32bit ops

src/s390/macro-assembler-s390.cc

Index: src/s390/macro-assembler-s390.cc
diff --git a/src/s390/macro-assembler-s390.cc b/src/s390/macro-assembler-s390.cc
index ea1079e4d658244bd75002fedb368afde0500ea2..120b208ae7d79669ea469c229c5fa192dace6a6b 100644
--- a/src/s390/macro-assembler-s390.cc
+++ b/src/s390/macro-assembler-s390.cc
@@ -1925,7 +1925,7 @@ void MacroAssembler::AllocateTwoByteString(Register result, Register length,
   // observing object alignment.
   DCHECK((SeqTwoByteString::kHeaderSize & kObjectAlignmentMask) == 0);
 
-  ShiftLeft(scratch1, length, Operand(1));  // Length in bytes, not chars.
+  ShiftLeftP(scratch1, length, Operand(1));  // Length in bytes, not chars.
   AddP(scratch1, Operand(kObjectAlignmentMask + SeqTwoByteString::kHeaderSize));
 
   AndP(scratch1, Operand(~kObjectAlignmentMask));
@@ -4895,6 +4895,15 @@ void MacroAssembler::StoreMultipleW(Register src1, Register src2,
 }
 
 // Load 32-bits and sign extend if necessary.
+void MacroAssembler::LoadW(Register dst, Register src) {
+#if V8_TARGET_ARCH_S390X
+  lgfr(dst, src);
+#else
+  if (!dst.is(src)) lr(dst, src);
+#endif
+}
+
+// Load 32-bits and sign extend if necessary.
 void MacroAssembler::LoadW(Register dst, const MemOperand& mem,
                            Register scratch) {
   int offset = mem.offset();
@@ -4920,6 +4929,15 @@ void MacroAssembler::LoadW(Register dst, const MemOperand& mem,
   }
 }
 
+// Load 32-bits and zero extend if necessary.
+void MacroAssembler::LoadlW(Register dst, Register src) {
+#if V8_TARGET_ARCH_S390X
+  llgfr(dst, src);
+#else
+  if (!dst.is(src)) lr(dst, src);
+#endif
+}
+
 // Variable length depending on whether offset fits into immediate field
 // MemOperand of RX or RXY format
 void MacroAssembler::LoadlW(Register dst, const MemOperand& mem,