Revert r4444 "Inline fast cases in string keyed load IC."

Review URL: http://codereview.chromium.org/1633024

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4445 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/globals.h

@@ -147,9 +147,6 @@ const int kPointerSizeLog2 = 2;
 const intptr_t kIntptrSignBit = 0x80000000;
 #endif
 
-// Mask for the sign bit in a smi.
-const intptr_t kSmiSignMask = kIntptrSignBit;
-
 const int kObjectAlignmentBits = kPointerSizeLog2;
 const intptr_t kObjectAlignment = 1 << kObjectAlignmentBits;
 const intptr_t kObjectAlignmentMask = kObjectAlignment - 1;

src/ia32/codegen-ia32.h

@@ -883,85 +883,53 @@ class GenericBinaryOpStub: public CodeStub {
 };
 
 
-class StringHelper : public AllStatic {
+class StringStubBase: public CodeStub {
  public:
-  // Generates fast code for getting a char code out of a string
-  // object at the given index. May bail out for three reasons (in the
-  // listed order):
-  //   * Receiver is not a string (receiver_not_string label).
-  //   * Index is not a positive smi (index_not_positive_smi label).
-  //   * Some other reason (slow_case label). In this case it's
-  //     guaranteed that the above conditions are not violated,
-  //     e.g. it's safe to assume the receiver is a string and the
-  //     index is a positive smi.
-  // When successful, object, index, and scratch are clobbered.
-  // Otherwise, scratch and result are clobbered.
-  static void GenerateFastCharCodeAt(MacroAssembler* masm,
-                                     Register object,
-                                     Register index,
-                                     Register scratch,
-                                     Register result,
-                                     Label* receiver_not_string,
-                                     Label* index_not_positive_smi,
-                                     Label* slow_case);
-
-  // Generates code for creating a one-char string from the given char
-  // code. May do a runtime call, so any register can be clobbered
-  // and, if the given invoke flag specifies a call, an internal frame
-  // is required. In tail call mode the result must be eax register.
-  static void GenerateCharFromCode(MacroAssembler* masm,
-                                   Register code,
-                                   Register result,
-                                   InvokeFlag flag);
-
   // Generate code for copying characters using a simple loop. This should only
   // be used in places where the number of characters is small and the
   // additional setup and checking in GenerateCopyCharactersREP adds too much
   // overhead. Copying of overlapping regions is not supported.
-  static void GenerateCopyCharacters(MacroAssembler* masm,
-                                     Register dest,
-                                     Register src,
-                                     Register count,
-                                     Register scratch,
-                                     bool ascii);
+  void GenerateCopyCharacters(MacroAssembler* masm,
+                              Register dest,
+                              Register src,
+                              Register count,
+                              Register scratch,
+                              bool ascii);
 
   // Generate code for copying characters using the rep movs instruction.
   // Copies ecx characters from esi to edi. Copying of overlapping regions is
   // not supported.
-  static void GenerateCopyCharactersREP(MacroAssembler* masm,
-                                        Register dest,     // Must be edi.
-                                        Register src,      // Must be esi.
-                                        Register count,    // Must be ecx.
-                                        Register scratch,  // Neither of above.
-                                        bool ascii);
+  void GenerateCopyCharactersREP(MacroAssembler* masm,
+                                 Register dest,     // Must be edi.
+                                 Register src,      // Must be esi.
+                                 Register count,    // Must be ecx.
+                                 Register scratch,  // Neither of the above.
+                                 bool ascii);
 
   // Probe the symbol table for a two character string. If the string is
   // not found by probing a jump to the label not_found is performed. This jump
   // does not guarantee that the string is not in the symbol table. If the
   // string is found the code falls through with the string in register eax.
-  static void GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
-                                                   Register c1,
-                                                   Register c2,
-                                                   Register scratch1,
-                                                   Register scratch2,
-                                                   Register scratch3,
-                                                   Label* not_found);
+  void GenerateTwoCharacterSymbolTableProbe(MacroAssembler* masm,
+                                            Register c1,
+                                            Register c2,
+                                            Register scratch1,
+                                            Register scratch2,
+                                            Register scratch3,
+                                            Label* not_found);
 
   // Generate string hash.
-  static void GenerateHashInit(MacroAssembler* masm,
-                               Register hash,
-                               Register character,
-                               Register scratch);
-  static void GenerateHashAddCharacter(MacroAssembler* masm,
-                                       Register hash,
-                                       Register character,
-                                       Register scratch);
-  static void GenerateHashGetHash(MacroAssembler* masm,
-                                  Register hash,
-                                  Register scratch);
-
- private:
-  DISALLOW_IMPLICIT_CONSTRUCTORS(StringHelper);
+  void GenerateHashInit(MacroAssembler* masm,
+                        Register hash,
+                        Register character,
+                        Register scratch);
+  void GenerateHashAddCharacter(MacroAssembler* masm,
+                                Register hash,
+                                Register character,
+                                Register scratch);
+  void GenerateHashGetHash(MacroAssembler* masm,
+                           Register hash,
+                           Register scratch);
 };
 
 
@@ -972,7 +940,7 @@ enum StringAddFlags {
 };
 
 
-class StringAddStub: public CodeStub {
+class StringAddStub: public StringStubBase {
  public:
   explicit StringAddStub(StringAddFlags flags) {
     string_check_ = ((flags & NO_STRING_CHECK_IN_STUB) == 0);
@@ -989,7 +957,7 @@ class StringAddStub: public CodeStub {
 };
 
 
-class SubStringStub: public CodeStub {
+class SubStringStub: public StringStubBase {
  public:
   SubStringStub() {}
 
@@ -1001,7 +969,7 @@ class SubStringStub: public CodeStub {
 };
 
 
-class StringCompareStub: public CodeStub {
+class StringCompareStub: public StringStubBase {
  public:
   explicit StringCompareStub() {
   }

src/ia32/ic-ia32.cc

@@ -491,58 +491,39 @@ void KeyedLoadIC::GenerateGeneric(MacroAssembler* masm) {
 
 void KeyedLoadIC::GenerateString(MacroAssembler* masm) {
   // ----------- S t a t e -------------
-  //  -- eax    : key (index)
+  //  -- eax    : key
   //  -- edx    : receiver
   //  -- esp[0] : return address
   // -----------------------------------
-  Label miss;
-  Label not_positive_smi;
-  Label slow_char_code;
-  Label got_char_code;
+  Label miss, index_ok;
 
-  Register receiver = edx;
-  Register index = eax;
-  Register code = ebx;
-  Register scratch = ecx;
-
-  StringHelper::GenerateFastCharCodeAt(masm,
-                                       receiver,
-                                       index,
-                                       scratch,
-                                       code,
-                                       &miss,  // When not a string.
-                                       &not_positive_smi,
-                                       &slow_char_code);
-  // If we didn't bail out, code register contains smi tagged char
-  // code.
-  __ bind(&got_char_code);
-  StringHelper::GenerateCharFromCode(masm, code, eax, JUMP_FUNCTION);
-#ifdef DEBUG
-  __ Abort("Unexpected fall-through from char from code tail call");
-#endif
+  // Pop return address.
+  // Performing the load early is better in the common case.
+  __ pop(ebx);
+
+  __ test(edx, Immediate(kSmiTagMask));
+  __ j(zero, &miss);
+  __ mov(ecx, FieldOperand(edx, HeapObject::kMapOffset));
+  __ movzx_b(ecx, FieldOperand(ecx, Map::kInstanceTypeOffset));
+  __ test(ecx, Immediate(kIsNotStringMask));
+  __ j(not_zero, &miss);
 
   // Check if key is a smi or a heap number.
-  __ bind(&not_positive_smi);
-  ASSERT(kSmiTag == 0);
-  __ test(index, Immediate(kSmiTagMask));
-  __ j(zero, &slow_char_code);
+  __ test(eax, Immediate(kSmiTagMask));
+  __ j(zero, &index_ok);
   __ mov(ecx, FieldOperand(eax, HeapObject::kMapOffset));
   __ cmp(ecx, Factory::heap_number_map());
   __ j(not_equal, &miss);
 
-  // Push receiver and key on the stack (now that we know they are a
-  // string and a number), and call runtime.
-  __ bind(&slow_char_code);
-  __ EnterInternalFrame();
-  __ push(receiver);
-  __ push(index);
-  __ CallRuntime(Runtime::kStringCharCodeAt, 1);
-  ASSERT(!code.is(eax));
-  __ mov(code, eax);
-  __ LeaveInternalFrame();
-  __ jmp(&got_char_code);
+  __ bind(&index_ok);
+  // Push receiver and key on the stack, and make a tail call.
+  __ push(edx);  // receiver
+  __ push(eax);  // key
+  __ push(ebx);  // return address
+  __ InvokeBuiltin(Builtins::STRING_CHAR_AT, JUMP_FUNCTION);
 
   __ bind(&miss);
+  __ push(ebx);
   GenerateMiss(masm);
 }