RegExpMacroAssembler::CheckStackGuardState should update input string pointer...

RegExpMacroAssembler::CheckStackGuardState should update input string pointer when it is moved or changed by GC.

If input string was cons-string it might undergo short-circuiting during GC. This does not change input start if underlying seq-string (first element of cons-string) does not move but this makes input-string pointer on the native regexp's frame invalid.

R=lrn@chromium.org

Review URL: http://codereview.chromium.org/8343001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9697 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/regexp-macro-assembler-arm.cc

@@ -1111,6 +1111,11 @@ int RegExpMacroAssemblerARM::CheckStackGuardState(Address* return_address,
     frame_entry<const String*>(re_frame, kInputString) = *subject;
     frame_entry<const byte*>(re_frame, kInputStart) = new_address;
     frame_entry<const byte*>(re_frame, kInputEnd) = new_address + byte_length;
+  } else if (frame_entry<const String*>(re_frame, kInputString) != *subject) {
+    // Subject string might have been a ConsString that underwent
+    // short-circuiting during GC. That will not change start_address but
+    // will change pointer inside the subject handle.
+    frame_entry<const String*>(re_frame, kInputString) = *subject;
   }
 
   return 0;

src/ia32/regexp-macro-assembler-ia32.cc

@@ -1141,6 +1141,11 @@ int RegExpMacroAssemblerIA32::CheckStackGuardState(Address* return_address,
     frame_entry<const String*>(re_frame, kInputString) = *subject;
     frame_entry<const byte*>(re_frame, kInputStart) = new_address;
     frame_entry<const byte*>(re_frame, kInputEnd) = new_address + byte_length;
+  } else if (frame_entry<const String*>(re_frame, kInputString) != *subject) {
+    // Subject string might have been a ConsString that underwent
+    // short-circuiting during GC. That will not change start_address but
+    // will change pointer inside the subject handle.
+    frame_entry<const String*>(re_frame, kInputString) = *subject;
   }
 
   return 0;

src/x64/regexp-macro-assembler-x64.cc

@@ -1248,6 +1248,11 @@ int RegExpMacroAssemblerX64::CheckStackGuardState(Address* return_address,
     frame_entry<const String*>(re_frame, kInputString) = *subject;
     frame_entry<const byte*>(re_frame, kInputStart) = new_address;
     frame_entry<const byte*>(re_frame, kInputEnd) = new_address + byte_length;
+  } else if (frame_entry<const String*>(re_frame, kInputString) != *subject) {
+    // Subject string might have been a ConsString that underwent
+    // short-circuiting during GC. That will not change start_address but
+    // will change pointer inside the subject handle.
+    frame_entry<const String*>(re_frame, kInputString) = *subject;
   }
 
   return 0;