MIPS: Improve array to string conversion.

Port r13144 (71c45300)

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/11573017
Patch from Akos Palfi <palfia@homejinni.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13230 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/codegen-mips.cc

@@ -517,6 +517,50 @@ void StringCharLoadGenerator::Generate(MacroAssembler* masm,
 }
 
 
+void SeqStringSetCharGenerator::Generate(MacroAssembler* masm,
+                                         String::Encoding encoding,
+                                         Register string,
+                                         Register index,
+                                         Register value) {
+  if (FLAG_debug_code) {
+    __ And(at, index, Operand(kSmiTagMask));
+    __ Check(eq, "Non-smi index", at, Operand(zero_reg));
+    __ And(at, value, Operand(kSmiTagMask));
+    __ Check(eq, "Non-smi value", at, Operand(zero_reg));
+
+    __ lw(at, FieldMemOperand(string, String::kLengthOffset));
+    __ Check(lt, "Index is too large", at, Operand(index));
+
+    __ Check(ge, "Index is negative", index, Operand(Smi::FromInt(0)));
+
+    __ lw(at, FieldMemOperand(string, HeapObject::kMapOffset));
+    __ lbu(at, FieldMemOperand(at, Map::kInstanceTypeOffset));
+
+    __ And(at, at, Operand(kStringRepresentationMask | kStringEncodingMask));
+    static const uint32_t one_byte_seq_type = kSeqStringTag | kOneByteStringTag;
+    static const uint32_t two_byte_seq_type = kSeqStringTag | kTwoByteStringTag;
+    __ Check(eq, "Unexpected string type", at,
+        Operand(encoding == String::ONE_BYTE_ENCODING
+                    ? one_byte_seq_type : two_byte_seq_type));
+  }
+
+  __ Addu(at,
+          string,
+          Operand(SeqString::kHeaderSize - kHeapObjectTag));
+  __ SmiUntag(value);
+  STATIC_ASSERT(kSmiTagSize == 1 && kSmiTag == 0);
+  if (encoding == String::ONE_BYTE_ENCODING) {
+    __ SmiUntag(index);
+    __ Addu(at, at, index);
+    __ sb(value, MemOperand(at));
+  } else {
+    // No need to untag a smi for two-byte addressing.
+    __ Addu(at, at, index);
+    __ sh(value, MemOperand(at));
+  }
+}
+
+
 static MemOperand ExpConstant(int index, Register base) {
   return MemOperand(base, index * kDoubleSize);
 }

src/mips/full-codegen-mips.cc

@@ -3146,6 +3146,38 @@ void FullCodeGenerator::EmitDateField(CallRuntime* expr) {
 }
 
 
+void FullCodeGenerator::EmitOneByteSeqStringSetChar(CallRuntime* expr) {
+  ZoneList<Expression*>* args = expr->arguments();
+  ASSERT_EQ(3, args->length());
+
+  VisitForStackValue(args->at(1));  // index
+  VisitForStackValue(args->at(2));  // value
+  __ pop(a2);
+  __ pop(a1);
+  VisitForAccumulatorValue(args->at(0));  // string
+
+  static const String::Encoding encoding = String::ONE_BYTE_ENCODING;
+  SeqStringSetCharGenerator::Generate(masm_, encoding, v0, a1, a2);
+  context()->Plug(v0);
+}
+
+
+void FullCodeGenerator::EmitTwoByteSeqStringSetChar(CallRuntime* expr) {
+  ZoneList<Expression*>* args = expr->arguments();
+  ASSERT_EQ(3, args->length());
+
+  VisitForStackValue(args->at(1));  // index
+  VisitForStackValue(args->at(2));  // value
+  __ pop(a2);
+  __ pop(a1);
+  VisitForAccumulatorValue(args->at(0));  // string
+
+  static const String::Encoding encoding = String::TWO_BYTE_ENCODING;
+  SeqStringSetCharGenerator::Generate(masm_, encoding, v0, a1, a2);
+  context()->Plug(v0);
+}
+
+
 void FullCodeGenerator::EmitMathPow(CallRuntime* expr) {
   // Load the arguments on the stack and call the runtime function.
   ZoneList<Expression*>* args = expr->arguments();

src/mips/lithium-codegen-mips.cc

@@ -1389,6 +1389,15 @@ void LCodeGen::DoDateField(LDateField* instr) {
 }
 
 
+void LCodeGen::DoSeqStringSetChar(LSeqStringSetChar* instr) {
+  SeqStringSetCharGenerator::Generate(masm(),
+                                      instr->encoding(),
+                                      ToRegister(instr->string()),
+                                      ToRegister(instr->index()),
+                                      ToRegister(instr->value()));
+}
+
+
 void LCodeGen::DoBitNotI(LBitNotI* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());

src/mips/lithium-mips.cc

@@ -1531,6 +1531,16 @@ LInstruction* LChunkBuilder::DoDateField(HDateField* instr) {
 }
 
 
+LInstruction* LChunkBuilder::DoSeqStringSetChar(HSeqStringSetChar* instr) {
+  LOperand* string = UseRegister(instr->string());
+  LOperand* index = UseRegister(instr->index());
+  LOperand* value = UseRegister(instr->value());
+  LSeqStringSetChar* result =
+      new(zone()) LSeqStringSetChar(instr->encoding(), string, index, value);
+  return DefineAsRegister(result);
+}
+
+
 LInstruction* LChunkBuilder::DoBoundsCheck(HBoundsCheck* instr) {
   LOperand* value = UseRegisterOrConstantAtStart(instr->index());
   LOperand* length = UseRegister(instr->length());

src/mips/lithium-mips.h

@@ -148,6 +148,7 @@ class LCodeGen;
   V(Random)                                     \
   V(RegExpLiteral)                              \
   V(Return)                                     \
+  V(SeqStringSetChar)                           \
   V(ShiftI)                                     \
   V(SmiTag)                                     \
   V(SmiUntag)                                   \
@@ -1143,6 +1144,30 @@ class LDateField: public LTemplateInstruction<1, 1, 1> {
 };
 
 
+class LSeqStringSetChar: public LTemplateInstruction<1, 3, 0> {
+ public:
+  LSeqStringSetChar(String::Encoding encoding,
+                    LOperand* string,
+                    LOperand* index,
+                    LOperand* value) : encoding_(encoding) {
+    inputs_[0] = string;
+    inputs_[1] = index;
+    inputs_[2] = value;
+  }
+
+  String::Encoding encoding() { return encoding_; }
+  LOperand* string() { return inputs_[0]; }
+  LOperand* index() { return inputs_[1]; }
+  LOperand* value() { return inputs_[2]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(SeqStringSetChar, "seq-string-set-char")
+  DECLARE_HYDROGEN_ACCESSOR(SeqStringSetChar)
+
+ private:
+  String::Encoding encoding_;
+};
+
+
 class LThrow: public LTemplateInstruction<0, 1, 0> {
  public:
   explicit LThrow(LOperand* value) {