Internalize strings in-place

src/mips/codegen-mips.cc

Index: src/mips/codegen-mips.cc
diff --git a/src/mips/codegen-mips.cc b/src/mips/codegen-mips.cc
index a57299abf67bc55042bc764ca7069a9a0e3cf166..15011023ccdaad35a072844fad8abce5be3d9d1d 100644
--- a/src/mips/codegen-mips.cc
+++ b/src/mips/codegen-mips.cc
@@ -620,9 +620,10 @@ void StringCharLoadGenerator::Generate(MacroAssembler* masm,
   __ Branch(&check_sequential, eq, at, Operand(zero_reg));
 
   // Dispatch on the indirect string shape: slice or cons.
-  Label cons_string;
-  __ And(at, result, Operand(kSlicedNotConsMask));
-  __ Branch(&cons_string, eq, at, Operand(zero_reg));
+  Label cons_string, thin_string;
+  __ And(at, result, Operand(kStringRepresentationMask));
+  __ Branch(&cons_string, eq, at, Operand(kConsStringTag));
+  __ Branch(&thin_string, eq, at, Operand(kThinStringTag));
 
   // Handle slices.
   Label indirect_string_loaded;
@@ -632,6 +633,11 @@ void StringCharLoadGenerator::Generate(MacroAssembler* masm,
   __ Addu(index, index, at);
   __ jmp(&indirect_string_loaded);
 
+  // Handle thin strings.
+  __ bind(&thin_string);
+  __ lw(string, FieldMemOperand(string, ThinString::kActualOffset));
+  __ jmp(&indirect_string_loaded);
+
   // 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