PPC: [turbofan] Further fixing ES6 tail call elimination in Turbofan.

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

Index: src/compiler/ppc/code-generator-ppc.cc
diff --git a/src/compiler/ppc/code-generator-ppc.cc b/src/compiler/ppc/code-generator-ppc.cc
index 6bf0a7e80a75a59c7f1e0a0d618c6411a707c7d7..f20f476473a79867457d1e1d5245b8ac3e95abd4 100644
--- a/src/compiler/ppc/code-generator-ppc.cc
+++ b/src/compiler/ppc/code-generator-ppc.cc
@@ -685,6 +685,30 @@ void CodeGenerator::AssemblePrepareTailCall(int stack_param_delta) {
   frame_access_state()->SetFrameAccessToSP();
 }
 
+void CodeGenerator::AssemblePopArgumentsAdaptorFrame(Register args_reg,
+                                                     Register scratch1,
+                                                     Register scratch2,
+                                                     Register scratch3) {
+  DCHECK(!AreAliased(args_reg, scratch1, scratch2, scratch3));
+  Label done;
+
+  // Check if current frame is an arguments adaptor frame.
+  __ LoadP(scratch1, MemOperand(fp, StandardFrameConstants::kContextOffset));
+  __ CmpSmiLiteral(scratch1, Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR), r0);
+  __ bne(&done);
+
+  // Load arguments count from current arguments adaptor frame (note, it
+  // does not include receiver).
+  Register caller_args_count_reg = scratch1;
+  __ LoadP(caller_args_count_reg,
+           MemOperand(fp, ArgumentsAdaptorFrameConstants::kLengthOffset));
+  __ SmiUntag(caller_args_count_reg);
+
+  ParameterCount callee_args_count(args_reg);
+  __ PrepareForTailCall(callee_args_count, caller_args_count_reg, scratch2,
+                        scratch3);
+  __ bind(&done);
+}
 
 // Assembles an instruction after register allocation, producing machine code.
 void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
@@ -709,9 +733,15 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       frame_access_state()->ClearSPDelta();
       break;
     }
+    case kArchTailCallCodeObjectFromJSFunction:
     case kArchTailCallCodeObject: {
       int stack_param_delta = i.InputInt32(instr->InputCount() - 1);
       AssembleDeconstructActivationRecord(stack_param_delta);
+      if (opcode == kArchTailCallCodeObjectFromJSFunction) {
+        AssemblePopArgumentsAdaptorFrame(kJavaScriptCallArgCountRegister,
+                                         i.TempRegister(0), i.TempRegister(1),
+                                         i.TempRegister(2));
+      }
       if (HasRegisterInput(instr, 0)) {
         __ addi(ip, i.InputRegister(0),
                 Operand(Code::kHeaderSize - kHeapObjectTag));
@@ -746,6 +776,7 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       frame_access_state()->ClearSPDelta();
       break;
     }
+    case kArchTailCallJSFunctionFromJSFunction:
     case kArchTailCallJSFunction: {
       Register func = i.InputRegister(0);
       if (FLAG_debug_code) {
@@ -757,6 +788,11 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       }
       int stack_param_delta = i.InputInt32(instr->InputCount() - 1);
       AssembleDeconstructActivationRecord(stack_param_delta);
+      if (opcode == kArchTailCallJSFunctionFromJSFunction) {
+        AssemblePopArgumentsAdaptorFrame(kJavaScriptCallArgCountRegister,
+                                         i.TempRegister(0), i.TempRegister(1),
+                                         i.TempRegister(2));
+      }
       __ LoadP(ip, FieldMemOperand(func, JSFunction::kCodeEntryOffset));
       __ Jump(ip);
       DCHECK_EQ(LeaveRC, i.OutputRCBit());