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// Copyright 2017 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_EXECUTION_SIMULATOR_BASE_H_
#define V8_EXECUTION_SIMULATOR_BASE_H_
#include <type_traits>
#include "src/execution/isolate.h"
#include "src/globals.h"
#if defined(USE_SIMULATOR)
namespace v8 {
namespace internal {
class Instruction;
class Redirection;
class SimulatorBase {
public:
// Call on process start and exit.
static void InitializeOncePerProcess();
static void GlobalTearDown();
static base::Mutex* redirection_mutex() { return redirection_mutex_; }
static Redirection* redirection() { return redirection_; }
static void set_redirection(Redirection* r) { redirection_ = r; }
static base::Mutex* i_cache_mutex() { return i_cache_mutex_; }
static base::CustomMatcherHashMap* i_cache() { return i_cache_; }
// Runtime call support.
static Address RedirectExternalReference(Address external_function,
ExternalReference::Type type);
protected:
template <typename Return, typename SimT, typename CallImpl, typename... Args>
static Return VariadicCall(SimT* sim, CallImpl call, Address entry,
Args... args) {
// Convert all arguments to intptr_t. Fails if any argument is not integral
// or pointer.
std::array<intptr_t, sizeof...(args)> args_arr{{ConvertArg(args)...}};
intptr_t ret = (sim->*call)(entry, args_arr.size(), args_arr.data());
return ConvertReturn<Return>(ret);
}
// Convert back integral return types. This is always a narrowing conversion.
template <typename T>
static typename std::enable_if<std::is_integral<T>::value, T>::type
ConvertReturn(intptr_t ret) {
static_assert(sizeof(T) <= sizeof(intptr_t), "type bigger than ptrsize");
return static_cast<T>(ret);
}
// Convert back pointer-typed return types.
template <typename T>
static typename std::enable_if<std::is_pointer<T>::value, T>::type
ConvertReturn(intptr_t ret) {
return reinterpret_cast<T>(ret);
}
template <typename T>
static typename std::enable_if<std::is_base_of<Object, T>::value, T>::type
ConvertReturn(intptr_t ret) {
return Object(ret);
}
// Convert back void return type (i.e. no return).
template <typename T>
static typename std::enable_if<std::is_void<T>::value, T>::type ConvertReturn(
intptr_t ret) {}
private:
static base::Mutex* redirection_mutex_;
static Redirection* redirection_;
static base::Mutex* i_cache_mutex_;
static base::CustomMatcherHashMap* i_cache_;
// Helper methods to convert arbitrary integer or pointer arguments to the
// needed generic argument type intptr_t.
// Convert integral argument to intptr_t.
template <typename T>
static typename std::enable_if<std::is_integral<T>::value, intptr_t>::type
ConvertArg(T arg) {
static_assert(sizeof(T) <= sizeof(intptr_t), "type bigger than ptrsize");
#if V8_TARGET_ARCH_MIPS64
// The MIPS64 calling convention is to sign extend all values, even unsigned
// ones.
using signed_t = typename std::make_signed<T>::type;
return static_cast<intptr_t>(static_cast<signed_t>(arg));
#else
// Standard C++ convertion: Sign-extend signed values, zero-extend unsigned
// values.
return static_cast<intptr_t>(arg);
#endif
}
// Convert pointer-typed argument to intptr_t.
template <typename T>
static typename std::enable_if<std::is_pointer<T>::value, intptr_t>::type
ConvertArg(T arg) {
return reinterpret_cast<intptr_t>(arg);
}
};
// When the generated code calls an external reference we need to catch that in
// the simulator. The external reference will be a function compiled for the
// host architecture. We need to call that function instead of trying to
// execute it with the simulator. We do that by redirecting the external
// reference to a trapping instruction that is handled by the simulator. We
// write the original destination of the jump just at a known offset from the
// trapping instruction so the simulator knows what to call.
//
// The following are trapping instructions used for various architectures:
// - V8_TARGET_ARCH_ARM: svc (Supervisor Call)
// - V8_TARGET_ARCH_ARM64: svc (Supervisor Call)
// - V8_TARGET_ARCH_MIPS: swi (software-interrupt)
// - V8_TARGET_ARCH_MIPS64: swi (software-interrupt)
// - V8_TARGET_ARCH_PPC: svc (Supervisor Call)
// - V8_TARGET_ARCH_S390: svc (Supervisor Call)
class Redirection {
public:
Redirection(Address external_function, ExternalReference::Type type);
Address address_of_instruction() {
#if ABI_USES_FUNCTION_DESCRIPTORS
return reinterpret_cast<Address>(function_descriptor_);
#else
return reinterpret_cast<Address>(&instruction_);
#endif
}
void* external_function() {
return reinterpret_cast<void*>(external_function_);
}
ExternalReference::Type type() { return type_; }
static Redirection* Get(Address external_function,
ExternalReference::Type type);
static Redirection* FromInstruction(Instruction* instruction) {
Address addr_of_instruction = reinterpret_cast<Address>(instruction);
Address addr_of_redirection =
addr_of_instruction - offsetof(Redirection, instruction_);
return reinterpret_cast<Redirection*>(addr_of_redirection);
}
static void* ReverseRedirection(intptr_t reg) {
Redirection* redirection = FromInstruction(
reinterpret_cast<Instruction*>(reinterpret_cast<void*>(reg)));
return redirection->external_function();
}
static void DeleteChain(Redirection* redirection) {
while (redirection != nullptr) {
Redirection* next = redirection->next_;
delete redirection;
redirection = next;
}
}
private:
Address external_function_;
uint32_t instruction_;
ExternalReference::Type type_;
Redirection* next_;
#if ABI_USES_FUNCTION_DESCRIPTORS
intptr_t function_descriptor_[3];
#endif
};
} // namespace internal
} // namespace v8
#endif // defined(USE_SIMULATOR)
#endif // V8_EXECUTION_SIMULATOR_BASE_H_