[es6] Make new.target work in functions

src/mips/builtins-mips.cc

Index: src/mips/builtins-mips.cc
diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
index 2c80c75c7909eab488380ad3ff64c089eee99629..985f9c714f753f01412308bf2dd9170264efacb0 100644
--- a/src/mips/builtins-mips.cc
+++ b/src/mips/builtins-mips.cc
@@ -348,6 +348,7 @@ static void Generate_Runtime_NewObject(MacroAssembler* masm,
 
 static void Generate_JSConstructStubHelper(MacroAssembler* masm,
                                            bool is_api_function,
+                                           bool use_new_target,
                                            bool create_memento) {
   // ----------- S t a t e -------------
   //  -- a0     : number of arguments
@@ -379,9 +380,13 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
       __ push(a2);
     }
 
-    // Preserve the two incoming parameters on the stack.
-    __ sll(a0, a0, kSmiTagSize);  // Tag arguments count.
-    __ MultiPushReversed(a0.bit() | a1.bit());
+    // Preserve the incoming parameters on the stack.
+    __ SmiTag(a0);
+    if (use_new_target) {
+      __ Push(a0, a1, a3);
+    } else {
+      __ Push(a0, a1);
+    }
 
     Label rt_call, allocated, normal_new, count_incremented;
     __ Branch(&normal_new, eq, a1, Operand(a3));
@@ -628,7 +633,8 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     __ bind(&allocated);
 
     if (create_memento) {
-      __ lw(a2, MemOperand(sp, kPointerSize * 2));
+      int offset = (use_new_target ? 3 : 2) * kPointerSize;
+      __ lw(a2, MemOperand(sp, offset));
       __ LoadRoot(t5, Heap::kUndefinedValueRootIndex);
       __ Branch(&count_incremented, eq, a2, Operand(t5));
       // a2 is an AllocationSite. We are creating a memento from it, so we
@@ -641,22 +647,25 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
       __ bind(&count_incremented);
     }
 
+    // Restore the parameters.
+    if (use_new_target) {
+      __ Pop(a3);  // new.target
+    }
     __ Pop(a1);
 
-    __ Push(t4, t4);
+    // Retrieve smi-tagged arguments count from the stack.
+    __ lw(a0, MemOperand(sp));
+    __ SmiUntag(a0);
 
-    // Reload the number of arguments from the stack.
-    // sp[0]: receiver
-    // sp[1]: receiver
-    // sp[2]: number of arguments (smi-tagged)
-    __ lw(a3, MemOperand(sp, 2 * kPointerSize));
+    if (use_new_target) {
+      __ Push(a3, t4, t4);
+    } else {
+      __ Push(t4, t4);
+    }
 
     // Set up pointer to last argument.
     __ Addu(a2, fp, Operand(StandardFrameConstants::kCallerSPOffset));
 
-    // Set up number of arguments for function call below.
-    __ srl(a0, a3, kSmiTagSize);
-
     // Copy arguments and receiver to the expression stack.
     // a0: number of arguments
     // a1: constructor function
@@ -664,8 +673,10 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     // a3: number of arguments (smi-tagged)
     // sp[0]: receiver
     // sp[1]: receiver
-    // sp[2]: number of arguments (smi-tagged)
+    // sp[2]: new.target (if used)
+    // sp[2/3]: number of arguments (smi-tagged)
     Label loop, entry;
+    __ SmiTag(a3, a0);
     __ jmp(&entry);
     __ bind(&loop);
     __ sll(t0, a3, kPointerSizeLog2 - kSmiTagSize);
@@ -690,7 +701,9 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     }
 
     // Store offset of return address for deoptimizer.
-    if (!is_api_function) {
+    // TODO(arv): Remove the "!use_new_target" before supporting optimization
+    // of functions that reference new.target
+    if (!is_api_function && !use_new_target) {
       masm->isolate()->heap()->SetConstructStubDeoptPCOffset(masm->pc_offset());
     }
 
@@ -705,7 +718,8 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     // If the result is a smi, it is *not* an object in the ECMA sense.
     // v0: result
     // sp[0]: receiver (newly allocated object)
-    // sp[1]: number of arguments (smi-tagged)
+    // sp[1]: new.target (if used)
+    // sp[1/2]: number of arguments (smi-tagged)
     __ JumpIfSmi(v0, &use_receiver);
 
     // If the type of the result (stored in its map) is less than
@@ -723,8 +737,10 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     __ bind(&exit);
     // v0: result
     // sp[0]: receiver (newly allocated object)
-    // sp[1]: number of arguments (smi-tagged)
-    __ lw(a1, MemOperand(sp, kPointerSize));
+    // sp[1]: new.target (if used)
+    // sp[1/2]: number of arguments (smi-tagged)
+    int offset = (use_new_target ? 2 : 1) * kPointerSize;
+    __ lw(a1, MemOperand(sp, offset));
 
     // Leave construct frame.
   }
@@ -738,12 +754,17 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
 
 
 void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, false, FLAG_pretenuring_call_new);
+  Generate_JSConstructStubHelper(masm, false, false, FLAG_pretenuring_call_new);
 }
 
 
 void Builtins::Generate_JSConstructStubApi(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, true, false);
+  Generate_JSConstructStubHelper(masm, true, false, false);
+}
+
+
+void Builtins::Generate_JSConstructStubNewTarget(MacroAssembler* masm) {
+  Generate_JSConstructStubHelper(masm, false, true, FLAG_pretenuring_call_new);
 }