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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.
#ifndef V8_CODEGEN_TURBO_ASSEMBLER_H_
#define V8_CODEGEN_TURBO_ASSEMBLER_H_
#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.
// You will encounter two subclasses, TurboAssembler (derives from
// TurboAssemblerBase), and MacroAssembler (derives from TurboAssembler). The
// main difference is that MacroAssembler is allowed to access the isolate, and
// TurboAssembler accesses the isolate in a very limited way. TurboAssembler
// contains all the functionality that is used by Turbofan, and does not expect
// to be running on the main thread.
class V8_EXPORT_PRIVATE TurboAssemblerBase : public Assembler {
public:
// 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 {
DCHECK(!code_object_.is_null());
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(Builtin builtin) { maybe_builtin_ = builtin; }
void set_has_frame(bool v) { has_frame_ = v; }
bool has_frame() const { return has_frame_; }
// 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);
Address BuiltinEntry(Builtin builtin);
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;
static int32_t RootRegisterOffsetForRootIndex(RootIndex root_index);
static int32_t RootRegisterOffsetForBuiltin(Builtin builtin);
// 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);
#if defined(V8_TARGET_OS_WIN) || defined(V8_TARGET_OS_MACOS)
// Minimum page size. We must touch memory once per page when expanding the
// stack, to avoid access violations.
static constexpr int kStackPageSize = 4 * KB;
#endif
V8_INLINE std::string CommentForOffHeapTrampoline(const char* prefix,
Builtin builtin) {
if (!v8_flags.code_comments) return "";
std::ostringstream str;
str << "Inlined Trampoline for " << prefix << " to "
<< Builtins::name(builtin);
return str.str();
}
enum class RecordWriteCallMode { kDefault, kWasm };
protected:
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_ = v8_flags.trap_on_abort;
// Emit a C call to abort instead of a runtime call.
bool hard_abort_ = false;
// May be set while generating builtins.
Builtin maybe_builtin_ = Builtin::kNoBuiltinId;
bool has_frame_ = false;
int comment_depth_ = 0;
DISALLOW_IMPLICIT_CONSTRUCTORS(TurboAssemblerBase);
};
// Avoids emitting calls to the {Builtin::kAbort} builtin when emitting
// debug code during the lifetime of this scope object.
class V8_NODISCARD HardAbortScope {
public:
explicit HardAbortScope(TurboAssemblerBase* assembler)
: assembler_(assembler), old_value_(assembler->should_abort_hard()) {
assembler_->set_abort_hard(true);
}
~HardAbortScope() { assembler_->set_abort_hard(old_value_); }
private:
TurboAssemblerBase* assembler_;
bool old_value_;
};
} // namespace internal
} // namespace v8
#endif // V8_CODEGEN_TURBO_ASSEMBLER_H_
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