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// Copyright 2018 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.
#include <memory>
#include "src/base/template-utils.h"
#include "src/builtins/builtins.h"
#include "src/codegen/assembler-arch.h"
#include "src/roots/roots.h"
namespace v8 {
namespace internal {
// Common base class for platform-specific TurboAssemblers containing
// platform-independent bits.
class V8_EXPORT_PRIVATE TurboAssemblerBase : public Assembler {
// Constructors are declared public to inherit them in derived classes
// with `using` directive.
TurboAssemblerBase(Isolate* isolate, CodeObjectRequired create_code_object,
std::unique_ptr<AssemblerBuffer> buffer = {})
: TurboAssemblerBase(isolate, AssemblerOptions::Default(isolate),
create_code_object, std::move(buffer)) {}
TurboAssemblerBase(Isolate* isolate, const AssemblerOptions& options,
CodeObjectRequired create_code_object,
std::unique_ptr<AssemblerBuffer> buffer = {});
Isolate* isolate() const {
return isolate_;
Handle<HeapObject> CodeObject() const {
return code_object_;
bool root_array_available() const { return root_array_available_; }
void set_root_array_available(bool v) { root_array_available_ = v; }
bool trap_on_abort() const { return trap_on_abort_; }
bool should_abort_hard() const { return hard_abort_; }
void set_abort_hard(bool v) { hard_abort_ = v; }
void set_builtin_index(int i) { maybe_builtin_index_ = i; }
void set_has_frame(bool v) { has_frame_ = v; }
bool has_frame() const { return has_frame_; }
virtual void Jump(const ExternalReference& reference) = 0;
// Calls the builtin given by the Smi in |builtin|. If builtins are embedded,
// the trampoline Code object on the heap is not used.
virtual void CallBuiltinByIndex(Register builtin_index) = 0;
// Calls/jumps to the given Code object. If builtins are embedded, the
// trampoline Code object on the heap is not used.
virtual void CallCodeObject(Register code_object) = 0;
virtual void JumpCodeObject(Register code_object) = 0;
// Loads the given Code object's entry point into the destination register.
virtual void LoadCodeObjectEntry(Register destination,
Register code_object) = 0;
// Loads the given constant or external reference without embedding its direct
// pointer. The produced code is isolate-independent.
void IndirectLoadConstant(Register destination, Handle<HeapObject> object);
void IndirectLoadExternalReference(Register destination,
ExternalReference reference);
virtual void LoadFromConstantsTable(Register destination,
int constant_index) = 0;
// Corresponds to: destination = kRootRegister + offset.
virtual void LoadRootRegisterOffset(Register destination,
intptr_t offset) = 0;
// Corresponds to: destination = [kRootRegister + offset].
virtual void LoadRootRelative(Register destination, int32_t offset) = 0;
virtual void LoadRoot(Register destination, RootIndex index) = 0;
virtual void Trap() = 0;
virtual void DebugBreak() = 0;
static int32_t RootRegisterOffsetForRootIndex(RootIndex root_index);
static int32_t RootRegisterOffsetForBuiltinIndex(int builtin_index);
// Returns the root-relative offset to reference.address().
static intptr_t RootRegisterOffsetForExternalReference(
Isolate* isolate, const ExternalReference& reference);
// Returns the root-relative offset to the external reference table entry,
// which itself contains reference.address().
static int32_t RootRegisterOffsetForExternalReferenceTableEntry(
Isolate* isolate, const ExternalReference& reference);
// An address is addressable through kRootRegister if it is located within
// isolate->root_register_addressable_region().
static bool IsAddressableThroughRootRegister(
Isolate* isolate, const ExternalReference& reference);
// Minimum page size. We must touch memory once per page when expanding the
// stack, to avoid access violations.
static constexpr int kStackPageSize = 4 * KB;
void RecordCommentForOffHeapTrampoline(int builtin_index);
Isolate* const isolate_ = nullptr;
// This handle will be patched with the code object on installation.
Handle<HeapObject> code_object_;
// Whether kRootRegister has been initialized.
bool root_array_available_ = true;
// Immediately trap instead of calling {Abort} when debug code fails.
bool trap_on_abort_ = FLAG_trap_on_abort;
// Emit a C call to abort instead of a runtime call.
bool hard_abort_ = false;
// May be set while generating builtins.
int maybe_builtin_index_ = Builtins::kNoBuiltinId;
bool has_frame_ = false;
// Avoids emitting calls to the {Builtins::kAbort} builtin when emitting debug
// code during the lifetime of this scope object. For disabling debug code
// entirely use the {DontEmitDebugCodeScope} instead.
class HardAbortScope {
explicit HardAbortScope(TurboAssemblerBase* assembler)
: assembler_(assembler), old_value_(assembler->should_abort_hard()) {
~HardAbortScope() { assembler_->set_abort_hard(old_value_); }
TurboAssemblerBase* assembler_;
bool old_value_;
#ifdef DEBUG
struct CountIfValidRegisterFunctor {
template <typename RegType>
constexpr int operator()(int count, RegType reg) const {
return count + (reg.is_valid() ? 1 : 0);
template <typename RegType, typename... RegTypes,
// All arguments must be either Register or DoubleRegister.
typename = typename std::enable_if<
base::is_same<Register, RegType, RegTypes...>::value ||
base::is_same<DoubleRegister, RegType, RegTypes...>::value>::type>
inline bool AreAliased(RegType first_reg, RegTypes... regs) {
int num_different_regs = NumRegs(RegType::ListOf(first_reg, regs...));
int num_given_regs =
base::fold(CountIfValidRegisterFunctor{}, 0, first_reg, regs...);
return num_different_regs < num_given_regs;
} // namespace internal
} // namespace v8