// Copyright 2014 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. #ifndef V8_RUNTIME_RUNTIME_UTILS_H_ #define V8_RUNTIME_RUNTIME_UTILS_H_ #include "src/base/logging.h" #include "src/common/globals.h" #include "src/objects/objects.h" #include "src/runtime/runtime.h" namespace v8 { namespace internal { // A mechanism to return a pair of Object pointers in registers (if possible). // How this is achieved is calling convention-dependent. // All currently supported x86 compiles uses calling conventions that are cdecl // variants where a 64-bit value is returned in two 32-bit registers // (edx:eax on ia32, r1:r0 on ARM). // In AMD-64 calling convention a struct of two pointers is returned in rdx:rax. // In Win64 calling convention, a struct of two pointers is returned in memory, // allocated by the caller, and passed as a pointer in a hidden first parameter. #ifdef V8_HOST_ARCH_64_BIT struct ObjectPair { Address x; Address y; }; static inline ObjectPair MakePair(Object x, Object y) { ObjectPair result = {x.ptr(), y.ptr()}; // Pointers x and y returned in rax and rdx, in AMD-x64-abi. // In Win64 they are assigned to a hidden first argument. return result; } #else using ObjectPair = uint64_t; static inline ObjectPair MakePair(Object x, Object y) { #if defined(V8_TARGET_LITTLE_ENDIAN) return x.ptr() | (static_cast<ObjectPair>(y.ptr()) << 32); #elif defined(V8_TARGET_BIG_ENDIAN) return y->ptr() | (static_cast<ObjectPair>(x->ptr()) << 32); #else #error Unknown endianness #endif } #endif } // namespace internal } // namespace v8 #endif // V8_RUNTIME_RUNTIME_UTILS_H_