To fully support hydrogen code stubs which accept a variable number of arguments,

src/ia32/lithium-codegen-ia32.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2682 matching lines @@
   __ test(eax, Operand(eax));
   __ j(condition, &true_value, Label::kNear);
   __ mov(ToRegister(instr->result()), factory()->false_value());
   __ jmp(&done, Label::kNear);
   __ bind(&true_value);
   __ mov(ToRegister(instr->result()), factory()->true_value());
   __ bind(&done);
 }
 
 
+void LCodeGen::EmitReturn(LReturn* instr, bool dynamic_frame_alignment) {
+  int extra_value_count = dynamic_frame_alignment ? 2 : 1;
+
+  if (instr->has_constant_parameter_count()) {
+    int parameter_count = ToInteger32(instr->constant_parameter_count());
+    if (dynamic_frame_alignment && FLAG_debug_code) {
+      __ cmp(Operand(esp,
+                     (parameter_count + extra_value_count) * kPointerSize),
+             Immediate(kAlignmentZapValue));
+      __ Assert(equal, "expected alignment marker");
+    }
+    __ Ret((parameter_count + extra_value_count) * kPointerSize, ecx);
+  } else {
+    Register reg = ToRegister(instr->parameter_count());
+    Register return_addr_reg = reg.is(ecx) ? ebx : ecx;
+    if (dynamic_frame_alignment && FLAG_debug_code) {
+      ASSERT(extra_value_count == 2);
+      __ cmp(Operand(esp, reg, times_pointer_size,
+                     extra_value_count * kPointerSize),
+             Immediate(kAlignmentZapValue));
+      __ Assert(equal, "expected alignment marker");
+    }
+
+    // emit code to restore stack based on instr->parameter_count()
+    __ pop(return_addr_reg);  // save return address
+    if (dynamic_frame_alignment) {
+      __ inc(reg);  // 1 more for alignment
+    }
+    __ shl(reg, kPointerSizeLog2);
+    __ add(esp, reg);
+    __ jmp(return_addr_reg);
+  }
+}
+
+
 void LCodeGen::DoReturn(LReturn* instr) {
   if (FLAG_trace && info()->IsOptimizing()) {
     // Preserve the return value on the stack and rely on the runtime call
     // to return the value in the same register.  We're leaving the code
     // managed by the register allocator and tearing down the frame, it's
     // safe to write to the context register.
     __ push(eax);
     __ mov(esi, Operand(ebp, StandardFrameConstants::kContextOffset));
     __ CallRuntime(Runtime::kTraceExit, 1);
   }
@@ skipping 16 matching lines @@
       JavaScriptFrameConstants::kDynamicAlignmentStateOffset));
   }
   if (NeedsEagerFrame()) {
     __ mov(esp, ebp);
     __ pop(ebp);
   }
   if (dynamic_frame_alignment_) {
     Label no_padding;
     __ cmp(edx, Immediate(kNoAlignmentPadding));
     __ j(equal, &no_padding);
-    if (FLAG_debug_code) {
-      __ cmp(Operand(esp, (GetParameterCount() + 2) * kPointerSize),
-             Immediate(kAlignmentZapValue));
-      __ Assert(equal, "expected alignment marker");
-    }
-    __ Ret((GetParameterCount() + 2) * kPointerSize, ecx);
+
+    EmitReturn(instr, true);
     __ bind(&no_padding);
   }
-  if (info()->IsStub()) {
-    __ Ret();
-  } else {
-    __ Ret((GetParameterCount() + 1) * kPointerSize, ecx);
-  }
+
+  EmitReturn(instr, false);
 }
 
 
 void LCodeGen::DoLoadGlobalCell(LLoadGlobalCell* instr) {
   Register result = ToRegister(instr->result());
   __ mov(result, Operand::Cell(instr->hydrogen()->cell()));
   if (instr->hydrogen()->RequiresHoleCheck()) {
     __ cmp(result, factory()->the_hole_value());
     DeoptimizeIf(equal, instr->environment());
   }
@@ skipping 3497 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32