Internalize strings in-place

src/ia32/codegen-ia32.cc

Index: src/ia32/codegen-ia32.cc
diff --git a/src/ia32/codegen-ia32.cc b/src/ia32/codegen-ia32.cc
index ccd159e2991658a55b3f3381a954d824f0a238d5..339aa716f35afa616e5b8544c42eb512706766c6 100644
--- a/src/ia32/codegen-ia32.cc
+++ b/src/ia32/codegen-ia32.cc
@@ -501,9 +501,12 @@ void StringCharLoadGenerator::Generate(MacroAssembler* masm,
   __ j(zero, &check_sequential, Label::kNear);
 
   // Dispatch on the indirect string shape: slice or cons.
-  Label cons_string;
-  __ test(result, Immediate(kSlicedNotConsMask));
-  __ j(zero, &cons_string, Label::kNear);
+  Label cons_string, thin_string;
+  __ and_(result, Immediate(kStringRepresentationMask));
+  __ cmp(result, Immediate(kConsStringTag));
+  __ j(equal, &cons_string, Label::kNear);
+  __ cmp(result, Immediate(kThinStringTag));
+  __ j(equal, &thin_string, Label::kNear);
 
   // Handle slices.
   Label indirect_string_loaded;
@@ -513,6 +516,11 @@ void StringCharLoadGenerator::Generate(MacroAssembler* masm,
   __ mov(string, FieldOperand(string, SlicedString::kParentOffset));
   __ jmp(&indirect_string_loaded, Label::kNear);
 
+  // Handle thin strings.
+  __ bind(&thin_string);
+  __ mov(string, FieldOperand(string, ThinString::kActualOffset));
+  __ jmp(&indirect_string_loaded, Label::kNear);
+
   // Handle cons strings.
   // Check whether the right hand side is the empty string (i.e. if
   // this is really a flat string in a cons string). If that is not