PPC: [es6] Further fixing of tail Calls.

Port e519e6fa

Original commit message:
    1) Update profiling counters in Full codegen.
    2) Call Runtime::kTraceTailCall when tracing is on

    test/mjsunit/es6/tail-call-simple.js is disabled for now, because Turbofan does not fully support TCO yet.

R=ishell@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=v8:4698
LOG=N

Review URL: https://codereview.chromium.org/1690953003

Cr-Commit-Position: refs/heads/master@{#33951}

src/full-codegen/ppc/full-codegen-ppc.cc

@@ -411,6 +411,31 @@ void FullCodeGenerator::EmitBackEdgeBookkeeping(IterationStatement* stmt,
   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() + kCodeSizeMultiplier / 2;
+    weight = Min(kMaxBackEdgeWeight, Max(1, distance / kCodeSizeMultiplier));
+  }
+  EmitProfilingCounterDecrement(weight);
+  Label ok;
+  __ cmpi(r6, Operand::Zero());
+  __ bge(&ok);
+  // Don't need to save result register if we are going to do a tail call.
+  if (!is_tail_call) {
+    __ push(r3);
+  }
+  __ Call(isolate()->builtins()->InterruptCheck(), RelocInfo::CODE_TARGET);
+  if (!is_tail_call) {
+    __ pop(r3);
+  }
+  EmitProfilingCounterReset();
+  __ bind(&ok);
+}
 
 void FullCodeGenerator::EmitReturnSequence() {
   Comment cmnt(masm_, "[ Return sequence");
@@ -424,23 +449,7 @@ void FullCodeGenerator::EmitReturnSequence() {
       __ push(r3);
       __ 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() + kCodeSizeMultiplier / 2;
-      weight = Min(kMaxBackEdgeWeight, Max(1, distance / kCodeSizeMultiplier));
-    }
-    EmitProfilingCounterDecrement(weight);
-    Label ok;
-    __ cmpi(r6, Operand::Zero());
-    __ bge(&ok);
-    __ push(r3);
-    __ Call(isolate()->builtins()->InterruptCheck(), RelocInfo::CODE_TARGET);
-    __ pop(r3);
-    EmitProfilingCounterReset();
-    __ bind(&ok);
+    EmitProfilingCounterHandlingForReturnSequence(false);
 
     // Make sure that the constant pool is not emitted inside of the return
     // sequence.
@@ -2741,6 +2750,14 @@ void FullCodeGenerator::EmitCall(Call* expr, ConvertReceiverMode mode) {
 
   PrepareForBailoutForId(expr->CallId(), NO_REGISTERS);
   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();