From 56ca0091082aeda16567196e788f344d5a4694e8 Mon Sep 17 00:00:00 2001
From: "palfia@homejinni.com"
 <palfia@homejinni.com@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Thu, 7 Nov 2013 21:59:45 +0000
Subject: [PATCH] MIPS: Add new HSeqStringGetChar instruction.

Port r17565 (dce7927c)

Original commit message:
This instruction is required for copying characters from sequential
strings in the hydrogenized StringAddStub.

BUG=
R=plind44@gmail.com

Review URL: https://codereview.chromium.org/65483002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@17574 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/mips/lithium-codegen-mips.cc | 28 ++++++++++++++++++++++++++++
 src/mips/lithium-mips.cc         |  7 +++++++
 src/mips/lithium-mips.h          | 16 ++++++++++++++++
 3 files changed, 51 insertions(+)

diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index 5d09a30..2d8939f 100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -1756,6 +1756,34 @@ MemOperand LCodeGen::BuildSeqStringOperand(Register string,
 }
 
 
+void LCodeGen::DoSeqStringGetChar(LSeqStringGetChar* instr) {
+  String::Encoding encoding = instr->hydrogen()->encoding();
+  Register string = ToRegister(instr->string());
+  Register result = ToRegister(instr->result());
+
+  if (FLAG_debug_code) {
+    Register scratch = scratch0();
+    __ lw(scratch, FieldMemOperand(string, HeapObject::kMapOffset));
+    __ lbu(scratch, FieldMemOperand(scratch, Map::kInstanceTypeOffset));
+
+    __ And(scratch, scratch,
+           Operand(kStringRepresentationMask | kStringEncodingMask));
+    static const uint32_t one_byte_seq_type = kSeqStringTag | kOneByteStringTag;
+    static const uint32_t two_byte_seq_type = kSeqStringTag | kTwoByteStringTag;
+    __ Subu(at, scratch, Operand(encoding == String::ONE_BYTE_ENCODING
+                                ? one_byte_seq_type : two_byte_seq_type));
+    __ Check(eq, kUnexpectedStringType, at, Operand(zero_reg));
+  }
+
+  MemOperand operand = BuildSeqStringOperand(string, instr->index(), encoding);
+  if (encoding == String::ONE_BYTE_ENCODING) {
+    __ lbu(result, operand);
+  } else {
+    __ lhu(result, operand);
+  }
+}
+
+
 void LCodeGen::DoSeqStringSetChar(LSeqStringSetChar* instr) {
   String::Encoding encoding = instr->hydrogen()->encoding();
   Register string = ToRegister(instr->string());
diff --git a/src/mips/lithium-mips.cc b/src/mips/lithium-mips.cc
index 6f8d95e..7686096 100644
--- a/src/mips/lithium-mips.cc
+++ b/src/mips/lithium-mips.cc
@@ -1804,6 +1804,13 @@ LInstruction* LChunkBuilder::DoDateField(HDateField* instr) {
 }
 
 
+LInstruction* LChunkBuilder::DoSeqStringGetChar(HSeqStringGetChar* instr) {
+  LOperand* string = UseRegisterAtStart(instr->string());
+  LOperand* index = UseRegisterOrConstantAtStart(instr->index());
+  return DefineAsRegister(new(zone()) LSeqStringGetChar(string, index));
+}
+
+
 LInstruction* LChunkBuilder::DoSeqStringSetChar(HSeqStringSetChar* instr) {
   LOperand* string = UseRegister(instr->string());
   LOperand* index = UseRegisterOrConstant(instr->index());
diff --git a/src/mips/lithium-mips.h b/src/mips/lithium-mips.h
index 9b4d111..14bd29b 100644
--- a/src/mips/lithium-mips.h
+++ b/src/mips/lithium-mips.h
@@ -155,6 +155,7 @@ class LCodeGen;
   V(Random)                                     \
   V(RegExpLiteral)                              \
   V(Return)                                     \
+  V(SeqStringGetChar)                           \
   V(SeqStringSetChar)                           \
   V(ShiftI)                                     \
   V(SmiTag)                                     \
@@ -1340,6 +1341,21 @@ class LDateField V8_FINAL : public LTemplateInstruction<1, 1, 1> {
 };
 
 
+class LSeqStringGetChar V8_FINAL : public LTemplateInstruction<1, 2, 0> {
+ public:
+  LSeqStringGetChar(LOperand* string, LOperand* index) {
+    inputs_[0] = string;
+    inputs_[1] = index;
+  }
+
+  LOperand* string() const { return inputs_[0]; }
+  LOperand* index() const { return inputs_[1]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(SeqStringGetChar, "seq-string-get-char")
+  DECLARE_HYDROGEN_ACCESSOR(SeqStringGetChar)
+};
+
+
 class LSeqStringSetChar V8_FINAL : public LTemplateInstruction<1, 3, 0> {
  public:
   LSeqStringSetChar(LOperand* string,
-- 
2.7.4