X87: [Interpreter] Add ForInPrepare runtime function which returns a ObjectTriple.

src/x87/code-stubs-x87.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 1997 matching lines @@
   // ebp: frame pointer  (restored after C call)
   // esp: stack pointer  (restored after C call)
   // esi: current context (C callee-saved)
   // edi: JS function of the caller (C callee-saved)
   //
   // If argv_in_register():
   // ecx: pointer to the first argument
 
   ProfileEntryHookStub::MaybeCallEntryHook(masm);
 
+  // Reserve space on the stack for the three arguments passed to the call. If
+  // result size is greater than can be returned in registers, also reserve
+  // space for the hidden argument for the result location, and space for the
+  // result itself.
+  int arg_stack_space = result_size() < 3 ? 3 : 4 + result_size();
+
   // Enter the exit frame that transitions from JavaScript to C++.
   if (argv_in_register()) {
     DCHECK(!save_doubles());
-    __ EnterApiExitFrame(3);
+    __ EnterApiExitFrame(arg_stack_space);
 
     // Move argc and argv into the correct registers.
     __ mov(esi, ecx);
     __ mov(edi, eax);
   } else {
-    __ EnterExitFrame(save_doubles());
+    __ EnterExitFrame(arg_stack_space, save_doubles());
   }
 
   // ebx: pointer to C function  (C callee-saved)
   // ebp: frame pointer  (restored after C call)
   // esp: stack pointer  (restored after C call)
   // edi: number of arguments including receiver  (C callee-saved)
   // esi: pointer to the first argument (C callee-saved)
 
   // Result returned in eax, or eax+edx if result size is 2.
 
   // Check stack alignment.
   if (FLAG_debug_code) {
     __ CheckStackAlignment();
   }
+  // Call C function.
+  if (result_size() <= 2) {
+    __ mov(Operand(esp, 0 * kPointerSize), edi);  // argc.
+    __ mov(Operand(esp, 1 * kPointerSize), esi);  // argv.
+    __ mov(Operand(esp, 2 * kPointerSize),
+           Immediate(ExternalReference::isolate_address(isolate())));
+  } else {
+    DCHECK_EQ(3, result_size());
+    // Pass a pointer to the result location as the first argument.
+    __ lea(eax, Operand(esp, 4 * kPointerSize));
+    __ mov(Operand(esp, 0 * kPointerSize), eax);
+    __ mov(Operand(esp, 1 * kPointerSize), edi);  // argc.
+    __ mov(Operand(esp, 2 * kPointerSize), esi);  // argv.
+    __ mov(Operand(esp, 3 * kPointerSize),
+           Immediate(ExternalReference::isolate_address(isolate())));
+  }
+  __ call(ebx);
 
-  // Call C function.
-  __ mov(Operand(esp, 0 * kPointerSize), edi);  // argc.
-  __ mov(Operand(esp, 1 * kPointerSize), esi);  // argv.
-  __ mov(Operand(esp, 2 * kPointerSize),
-         Immediate(ExternalReference::isolate_address(isolate())));
-  __ call(ebx);
-  // Result is in eax or edx:eax - do not destroy these registers!
+  if (result_size() > 2) {
+    DCHECK_EQ(3, result_size());
+#ifndef _WIN32
+    // Restore the "hidden" argument on the stack which was popped by caller.
+    __ sub(esp, Immediate(kPointerSize));
+#endif
+    // Read result values stored on stack. Result is stored above the arguments.
+    __ mov(kReturnRegister0, Operand(esp, 4 * kPointerSize));
+    __ mov(kReturnRegister1, Operand(esp, 5 * kPointerSize));
+    __ mov(kReturnRegister2, Operand(esp, 6 * kPointerSize));
+  }
+  // Result is in eax, edx:eax or edi:edx:eax - do not destroy these registers!
 
   // Check result for exception sentinel.
   Label exception_returned;
   __ cmp(eax, isolate()->factory()->exception());
   __ j(equal, &exception_returned);
 
   // Check that there is no pending exception, otherwise we
   // should have returned the exception sentinel.
   if (FLAG_debug_code) {
     __ push(edx);
@@ skipping 3290 matching lines @@
                            Operand(ebp, 7 * kPointerSize), NULL);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87