[es6] Further fixing of tail Calls.

src/full-codegen/mips/full-codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_MIPS
 
 // Note on Mips implementation:
 //
 // The result_register() for mips is the 'v0' register, which is defined
 // by the ABI to contain function return values. However, the first
@@ skipping 396 matching lines @@
   EmitProfilingCounterReset();
 
   __ bind(&ok);
   PrepareForBailoutForId(stmt->EntryId(), NO_REGISTERS);
   // Record a mapping of the OSR id to this PC.  This is used if the OSR
   // entry becomes the target of a bailout.  We don't expect it to be, but
   // we want it to work if it is.
   PrepareForBailoutForId(stmt->OsrEntryId(), NO_REGISTERS);
 }
 
+void FullCodeGenerator::EmitProfilingCounterHandlingForReturnSequence(
+    bool is_tail_call) {
+  // Pretend that the exit is a backwards jump to the entry.
+  int weight = 1;
+  if (info_->ShouldSelfOptimize()) {
+    weight = FLAG_interrupt_budget / FLAG_self_opt_count;
+  } else {
+    int distance = masm_->pc_offset();
+    weight = Min(kMaxBackEdgeWeight, Max(1, distance / kCodeSizeMultiplier));
+  }
+  EmitProfilingCounterDecrement(weight);
+  Label ok;
+  __ Branch(&ok, ge, a3, Operand(zero_reg));
+  // Don't need to save result register if we are going to do a tail call.
+  if (!is_tail_call) {
+    __ push(v0);
+  }
+  __ Call(isolate()->builtins()->InterruptCheck(), RelocInfo::CODE_TARGET);
+  if (!is_tail_call) {
+    __ pop(v0);
+  }
+  EmitProfilingCounterReset();
+  __ bind(&ok);
+}
 
 void FullCodeGenerator::EmitReturnSequence() {
   Comment cmnt(masm_, "[ Return sequence");
   if (return_label_.is_bound()) {
     __ Branch(&return_label_);
   } else {
     __ bind(&return_label_);
     if (FLAG_trace) {
       // Push the return value on the stack as the parameter.
       // Runtime::TraceExit returns its parameter in v0.
       __ push(v0);
       __ CallRuntime(Runtime::kTraceExit);
     }
-    // Pretend that the exit is a backwards jump to the entry.
-    int weight = 1;
-    if (info_->ShouldSelfOptimize()) {
-      weight = FLAG_interrupt_budget / FLAG_self_opt_count;
-    } else {
-      int distance = masm_->pc_offset();
-      weight = Min(kMaxBackEdgeWeight,
-                   Max(1, distance / kCodeSizeMultiplier));
-    }
-    EmitProfilingCounterDecrement(weight);
-    Label ok;
-    __ Branch(&ok, ge, a3, Operand(zero_reg));
-    __ push(v0);
-    __ Call(isolate()->builtins()->InterruptCheck(),
-            RelocInfo::CODE_TARGET);
-    __ pop(v0);
-    EmitProfilingCounterReset();
-    __ bind(&ok);
+    EmitProfilingCounterHandlingForReturnSequence(false);
 
     // Make sure that the constant pool is not emitted inside of the return
     // sequence.
     { Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm_);
       // Here we use masm_-> instead of the __ macro to avoid the code coverage
       // tool from instrumenting as we rely on the code size here.
       int32_t arg_count = info_->scope()->num_parameters() + 1;
       int32_t sp_delta = arg_count * kPointerSize;
       SetReturnPosition(literal());
       masm_->mov(sp, fp);
@@ skipping 2276 matching lines @@
   // Load the arguments.
   ZoneList<Expression*>* args = expr->arguments();
   int arg_count = args->length();
   for (int i = 0; i < arg_count; i++) {
     VisitForStackValue(args->at(i));
   }
 
   PrepareForBailoutForId(expr->CallId(), NO_REGISTERS);
   // Record source position of the IC call.
   SetCallPosition(expr);
+  if (expr->tail_call_mode() == TailCallMode::kAllow) {
+    if (FLAG_trace) {
+      __ CallRuntime(Runtime::kTraceTailCall);
+    }
+    // Update profiling counters before the tail call since we will
+    // not return to this function.
+    EmitProfilingCounterHandlingForReturnSequence(true);
+  }
   Handle<Code> ic =
       CodeFactory::CallIC(isolate(), arg_count, mode, expr->tail_call_mode())
           .code();
   __ li(a3, Operand(SmiFromSlot(expr->CallFeedbackICSlot())));
   __ lw(a1, MemOperand(sp, (arg_count + 1) * kPointerSize));
   // Don't assign a type feedback id to the IC, since type feedback is provided
   // by the vector above.
   CallIC(ic);
 
   RecordJSReturnSite(expr);
@@ skipping 1914 matching lines @@
          reinterpret_cast<uint32_t>(
              isolate->builtins()->OsrAfterStackCheck()->entry()));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS