PPC: Handle StepIn for constructors through PrepareStep just like for regular calls

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

Index: src/full-codegen/ppc/full-codegen-ppc.cc
diff --git a/src/full-codegen/ppc/full-codegen-ppc.cc b/src/full-codegen/ppc/full-codegen-ppc.cc
index 9850f7cf57ef1ed6444cfea6e1d512c37510b7cb..ee7f1b3207a4ec87f27b6802d064710242a37dd7 100644
--- a/src/full-codegen/ppc/full-codegen-ppc.cc
+++ b/src/full-codegen/ppc/full-codegen-ppc.cc
@@ -3082,7 +3082,7 @@ void FullCodeGenerator::VisitCallNew(CallNew* expr) {
 
   // Call the construct call builtin that handles allocation and
   // constructor invocation.
-  SetConstructCallPosition(expr);
+  SetConstructCallPosition(expr, arg_count);
 
   // Load function and argument count into r4 and r3.
   __ mov(r3, Operand(arg_count));
@@ -3118,7 +3118,7 @@ void FullCodeGenerator::EmitSuperConstructorCall(Call* expr) {
 
   // Call the construct call builtin that handles allocation and
   // constructor invocation.
-  SetConstructCallPosition(expr);
+  SetConstructCallPosition(expr, arg_count);
 
   // Load new target into r7.
   VisitForAccumulatorValue(super_call_ref->new_target_var());
@@ -3850,21 +3850,23 @@ void FullCodeGenerator::EmitDefaultConstructorCallSuper(CallRuntime* expr) {
   ZoneList<Expression*>* args = expr->arguments();
   DCHECK(args->length() == 2);
 
-  // Evaluate new.target.
+  // Evaluate new.target and super constructor.
   VisitForStackValue(args->at(0));
+  VisitForStackValue(args->at(1));
 
-  // Evaluate super constructor (to stack and r4).
-  VisitForAccumulatorValue(args->at(1));
-  __ push(result_register());
-  __ mr(r4, result_register());
-
-  // Load new target into r6.
-  __ LoadP(r6, MemOperand(sp, 1 * kPointerSize));
+  // Call the construct call builtin that handles allocation and
+  // constructor invocation.
+  SetConstructCallPosition(expr, 0);
 
   // Check if the calling frame is an arguments adaptor frame.
   Label adaptor_frame, args_set_up, runtime;
   __ LoadP(r5, MemOperand(fp, StandardFrameConstants::kCallerFPOffset));
   __ LoadP(r7, MemOperand(r5, StandardFrameConstants::kContextOffset));
+
+  // Load super constructor, new target into r4, r6.
+  __ LoadP(r4, MemOperand(sp));
+  __ LoadP(r6, MemOperand(sp, 1 * kPointerSize));
+
   __ CmpSmiLiteral(r7, Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR), r0);
   __ beq(&adaptor_frame);