[turbofan] Initial support for Switch.

src/compiler/x64/code-generator-x64.cc

Index: src/compiler/x64/code-generator-x64.cc
diff --git a/src/compiler/x64/code-generator-x64.cc b/src/compiler/x64/code-generator-x64.cc
index f5117f292a8cc300c98ec0273e40edb6f473fd7f..bad87b2fff73c65d44e0fc1bb7f90f08d5e1cca9 100644
--- a/src/compiler/x64/code-generator-x64.cc
+++ b/src/compiler/x64/code-generator-x64.cc
@@ -532,6 +532,9 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kArchJmp:
       AssembleArchJump(i.InputRpo(0));
       break;
+    case kArchSwitch:
+      AssembleArchSwitch(instr);
+      break;
     case kArchNop:
       // don't emit code for nops.
       break;
@@ -1067,6 +1070,19 @@ void CodeGenerator::AssembleArchJump(BasicBlock::RpoNumber target) {
 }
 
 
+void CodeGenerator::AssembleArchSwitch(Instruction* instr) {
+  X64OperandConverter i(this, instr);
+  size_t const label_count = instr->InputCount() - 1;
+  Label** labels = zone()->NewArray<Label*>(static_cast<int>(label_count));
+  for (size_t index = 0; index < label_count; ++index) {
+    labels[index] = GetLabel(i.InputRpo(static_cast<int>(index + 1)));
+  }
+  Label* const table = AddJumpTable(labels, label_count);
+  __ leaq(kScratchRegister, Operand(table));
+  __ jmp(Operand(kScratchRegister, i.InputRegister(0), times_8, 0));
+}
+
+
 // Assembles boolean materializations after this instruction.
 void CodeGenerator::AssembleArchBoolean(Instruction* instr,
                                         FlagsCondition condition) {
@@ -1380,6 +1396,13 @@ void CodeGenerator::AssembleSwap(InstructionOperand* source,
 }
 
 
+void CodeGenerator::AssembleJumpTable(Label** targets, size_t target_count) {
+  for (size_t index = 0; index < target_count; ++index) {
+    __ dq(targets[index]);
+  }
+}
+
+
 void CodeGenerator::AddNopForSmiCodeInlining() { __ nop(); }