Internalize strings in-place

src/s390/codegen-s390.cc

Index: src/s390/codegen-s390.cc
diff --git a/src/s390/codegen-s390.cc b/src/s390/codegen-s390.cc
index 02cc8c206c704338f94cd4e4d2798af5f0718a46..6b84200510af8245594c3fafac9385a8cdc462d7 100644
--- a/src/s390/codegen-s390.cc
+++ b/src/s390/codegen-s390.cc
@@ -70,6 +70,9 @@ void StubRuntimeCallHelper::AfterCall(MacroAssembler* masm) const {
 void StringCharLoadGenerator::Generate(MacroAssembler* masm, Register string,
                                        Register index, Register result,
                                        Label* call_runtime) {
+  Label indirect_string_loaded;
+  __ bind(&indirect_string_loaded);
+
   // Fetch the instance type of the receiver into result register.
   __ LoadP(result, FieldMemOperand(string, HeapObject::kMapOffset));
   __ LoadlB(result, FieldMemOperand(result, Map::kInstanceTypeOffset));
@@ -81,19 +84,25 @@ void StringCharLoadGenerator::Generate(MacroAssembler* masm, Register string,
   __ beq(&check_sequential, Label::kNear /*, cr0*/);
 
   // Dispatch on the indirect string shape: slice or cons.
-  Label cons_string;
-  __ mov(ip, Operand(kSlicedNotConsMask));
-  __ LoadRR(r0, result);
-  __ AndP(r0, ip /*, SetRC*/);  // Should be okay to remove RC
-  __ beq(&cons_string, Label::kNear /*, cr0*/);
+  Label cons_string, thin_string;
+  __ LoadRR(ip, result);
+  __ nilf(ip, Operand(kStringRepresentationMask));
+  __ CmpP(ip, Operand(kConsStringTag));
+  __ beq(&cons_string);
+  __ CmpP(ip, Operand(kThinStringTag));
+  __ beq(&thin_string);
 
   // Handle slices.
-  Label indirect_string_loaded;
   __ LoadP(result, FieldMemOperand(string, SlicedString::kOffsetOffset));
   __ LoadP(string, FieldMemOperand(string, SlicedString::kParentOffset));
   __ SmiUntag(ip, result);
   __ AddP(index, ip);
-  __ b(&indirect_string_loaded, Label::kNear);
+  __ b(&indirect_string_loaded);
+
+  // Handle thin strings.
+  __ bind(&thin_string);
+  __ LoadP(string, FieldMemOperand(string, ThinString::kActualOffset));
+  __ b(&indirect_string_loaded);
 
   // Handle cons strings.
   // Check whether the right hand side is the empty string (i.e. if
@@ -106,10 +115,7 @@ void StringCharLoadGenerator::Generate(MacroAssembler* masm, Register string,
   __ bne(call_runtime);
   // Get the first of the two strings and load its instance type.
   __ LoadP(string, FieldMemOperand(string, ConsString::kFirstOffset));
-
-  __ bind(&indirect_string_loaded);
-  __ LoadP(result, FieldMemOperand(string, HeapObject::kMapOffset));
-  __ LoadlB(result, FieldMemOperand(result, Map::kInstanceTypeOffset));
+  __ b(&indirect_string_loaded);
 
   // Distinguish sequential and external strings. Only these two string
   // representations can reach here (slices and flat cons strings have been