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/*
* Copyright (C) 2009-2019 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include "ExecutableAllocator.h"
#include "JSCPtrTag.h"
#include <wtf/DataLog.h>
#include <wtf/PrintStream.h>
#include <wtf/RefPtr.h>
#include <wtf/text/CString.h>
// ASSERT_VALID_CODE_POINTER checks that ptr is a non-null pointer, and that it is a valid
// instruction address on the platform (for example, check any alignment requirements).
#if CPU(ARM_THUMB2) && ENABLE(JIT)
// ARM instructions must be 16-bit aligned. Thumb2 code pointers to be loaded into
// into the processor are decorated with the bottom bit set, while traditional ARM has
// the lower bit clear. Since we don't know what kind of pointer, we check for both
// decorated and undecorated null.
#define ASSERT_NULL_OR_VALID_CODE_POINTER(ptr) \
ASSERT(!ptr || reinterpret_cast<intptr_t>(ptr) & ~1)
#define ASSERT_VALID_CODE_POINTER(ptr) \
ASSERT(reinterpret_cast<intptr_t>(ptr) & ~1)
#define ASSERT_VALID_CODE_OFFSET(offset) \
ASSERT(!(offset & 1)) // Must be multiple of 2.
#else
#define ASSERT_NULL_OR_VALID_CODE_POINTER(ptr) // Anything goes!
#define ASSERT_VALID_CODE_POINTER(ptr) \
ASSERT(ptr)
#define ASSERT_VALID_CODE_OFFSET(offset) // Anything goes!
#endif
namespace JSC {
template<PtrTag> class MacroAssemblerCodePtr;
enum OpcodeID : unsigned;
// CFunctionPtr can only be used to hold C/C++ functions.
class CFunctionPtr {
public:
using Ptr = void(*)();
CFunctionPtr() { }
CFunctionPtr(std::nullptr_t) { }
template<typename ReturnType, typename... Arguments>
constexpr CFunctionPtr(ReturnType(&ptr)(Arguments...))
: m_ptr(reinterpret_cast<Ptr>(&ptr))
{ }
template<typename ReturnType, typename... Arguments>
explicit CFunctionPtr(ReturnType(*ptr)(Arguments...))
: m_ptr(reinterpret_cast<Ptr>(ptr))
{
assertIsCFunctionPtr(m_ptr);
}
// MSVC doesn't seem to treat functions with different calling conventions as
// different types; these methods are already defined for fastcall, below.
#if CALLING_CONVENTION_IS_STDCALL && !OS(WINDOWS)
template<typename ReturnType, typename... Arguments>
constexpr CFunctionPtr(ReturnType(CDECL &ptr)(Arguments...))
: m_ptr(reinterpret_cast<Ptr>(&ptr))
{ }
template<typename ReturnType, typename... Arguments>
explicit CFunctionPtr(ReturnType(CDECL *ptr)(Arguments...))
: m_ptr(reinterpret_cast<Ptr>(ptr))
{
assertIsCFunctionPtr(m_ptr);
}
#endif // CALLING_CONVENTION_IS_STDCALL && !OS(WINDOWS)
#if COMPILER_SUPPORTS(FASTCALL_CALLING_CONVENTION)
template<typename ReturnType, typename... Arguments>
constexpr CFunctionPtr(ReturnType(FASTCALL &ptr)(Arguments...))
: m_ptr(reinterpret_cast<Ptr>(&ptr))
{ }
template<typename ReturnType, typename... Arguments>
explicit CFunctionPtr(ReturnType(FASTCALL *ptr)(Arguments...))
: m_ptr(reinterpret_cast<Ptr>(ptr))
{
assertIsCFunctionPtr(m_ptr);
}
#endif // COMPILER_SUPPORTS(FASTCALL_CALLING_CONVENTION)
constexpr Ptr get() const { return m_ptr; }
void* address() const { return reinterpret_cast<void*>(m_ptr); }
explicit operator bool() const { return !!m_ptr; }
bool operator!() const { return !m_ptr; }
bool operator==(const CFunctionPtr& other) const { return m_ptr == other.m_ptr; }
bool operator!=(const CFunctionPtr& other) const { return m_ptr != other.m_ptr; }
private:
Ptr m_ptr { nullptr };
};
// FunctionPtr:
//
// FunctionPtr should be used to wrap pointers to C/C++ functions in JSC
// (particularly, the stub functions).
template<PtrTag tag = CFunctionPtrTag>
class FunctionPtr {
public:
FunctionPtr() { }
FunctionPtr(std::nullptr_t) { }
template<typename ReturnType, typename... Arguments>
FunctionPtr(ReturnType(*value)(Arguments...))
: m_value(tagCFunctionPtr<void*, tag>(value))
{
assertIsNullOrCFunctionPtr(value);
ASSERT_NULL_OR_VALID_CODE_POINTER(m_value);
}
// MSVC doesn't seem to treat functions with different calling conventions as
// different types; these methods already defined for fastcall, below.
#if CALLING_CONVENTION_IS_STDCALL && !OS(WINDOWS)
template<typename ReturnType, typename... Arguments>
FunctionPtr(ReturnType(CDECL *value)(Arguments...))
: m_value(tagCFunctionPtr<void*, tag>(value))
{
assertIsNullOrCFunctionPtr(value);
ASSERT_NULL_OR_VALID_CODE_POINTER(m_value);
}
#endif // CALLING_CONVENTION_IS_STDCALL && !OS(WINDOWS)
#if COMPILER_SUPPORTS(FASTCALL_CALLING_CONVENTION)
template<typename ReturnType, typename... Arguments>
FunctionPtr(ReturnType(FASTCALL *value)(Arguments...))
: m_value(tagCFunctionPtr<void*, tag>(value))
{
assertIsNullOrCFunctionPtr(value);
ASSERT_NULL_OR_VALID_CODE_POINTER(m_value);
}
#endif // COMPILER_SUPPORTS(FASTCALL_CALLING_CONVENTION)
template<typename PtrType, typename = std::enable_if_t<std::is_pointer<PtrType>::value && !std::is_function<typename std::remove_pointer<PtrType>::type>::value>>
explicit FunctionPtr(PtrType value)
// Using a C-ctyle cast here to avoid compiler error on RVTC:
// Error: #694: reinterpret_cast cannot cast away const or other type qualifiers
// (I guess on RVTC function pointers have a different constness to GCC/MSVC?)
: m_value(tagCFunctionPtr<void*, tag>(value))
{
assertIsNullOrCFunctionPtr(value);
ASSERT_NULL_OR_VALID_CODE_POINTER(m_value);
}
explicit FunctionPtr(MacroAssemblerCodePtr<tag>);
template<PtrTag otherTag>
FunctionPtr<otherTag> retagged() const
{
if (!m_value)
return FunctionPtr<otherTag>();
return FunctionPtr<otherTag>(*this);
}
void* executableAddress() const
{
return m_value;
}
template<PtrTag newTag>
void* retaggedExecutableAddress() const
{
return retagCodePtr<tag, newTag>(m_value);
}
explicit operator bool() const { return !!m_value; }
bool operator!() const { return !m_value; }
bool operator==(const FunctionPtr& other) const { return m_value == other.m_value; }
bool operator!=(const FunctionPtr& other) const { return m_value != other.m_value; }
private:
template<PtrTag otherTag>
explicit FunctionPtr(const FunctionPtr<otherTag>& other)
: m_value(retagCodePtr<otherTag, tag>(other.executableAddress()))
{
ASSERT_NULL_OR_VALID_CODE_POINTER(m_value);
}
void* m_value { nullptr };
template<PtrTag> friend class FunctionPtr;
};
static_assert(sizeof(FunctionPtr<CFunctionPtrTag>) == sizeof(void*), "");
#if COMPILER_SUPPORTS(BUILTIN_IS_TRIVIALLY_COPYABLE)
static_assert(__is_trivially_copyable(FunctionPtr<CFunctionPtrTag>), "");
#endif
// ReturnAddressPtr:
//
// ReturnAddressPtr should be used to wrap return addresses generated by processor
// 'call' instructions exectued in JIT code. We use return addresses to look up
// exception and optimization information, and to repatch the call instruction
// that is the source of the return address.
class ReturnAddressPtr {
public:
ReturnAddressPtr() { }
explicit ReturnAddressPtr(const void* value)
: m_value(value)
{
ASSERT_VALID_CODE_POINTER(m_value);
}
const void* value() const
{
return m_value;
}
void dump(PrintStream& out) const
{
out.print(RawPointer(m_value));
}
private:
const void* m_value { nullptr };
};
// MacroAssemblerCodePtr:
//
// MacroAssemblerCodePtr should be used to wrap pointers to JIT generated code.
class MacroAssemblerCodePtrBase {
protected:
static void dumpWithName(void* executableAddress, void* dataLocation, const char* name, PrintStream& out);
};
// FIXME: Make JSC MacroAssemblerCodePtr injerit from MetaAllocatorPtr.
// https://bugs.webkit.org/show_bug.cgi?id=185145
template<PtrTag tag>
class MacroAssemblerCodePtr : private MacroAssemblerCodePtrBase {
public:
MacroAssemblerCodePtr() = default;
MacroAssemblerCodePtr(std::nullptr_t) : m_value(nullptr) { }
explicit MacroAssemblerCodePtr(const void* value)
#if CPU(ARM_THUMB2)
// Decorate the pointer as a thumb code pointer.
: m_value(reinterpret_cast<const char*>(value) + 1)
#else
: m_value(value)
#endif
{
assertIsTaggedWith(value, tag);
ASSERT(value);
#if CPU(ARM_THUMB2)
ASSERT(!(reinterpret_cast<uintptr_t>(value) & 1));
#endif
ASSERT_VALID_CODE_POINTER(m_value);
}
static MacroAssemblerCodePtr createFromExecutableAddress(const void* value)
{
ASSERT(value);
ASSERT_VALID_CODE_POINTER(value);
assertIsTaggedWith(value, tag);
MacroAssemblerCodePtr result;
result.m_value = value;
return result;
}
explicit MacroAssemblerCodePtr(ReturnAddressPtr ra)
: m_value(tagCodePtr<tag>(ra.value()))
{
assertIsNotTagged(ra.value());
ASSERT(ra.value());
ASSERT_VALID_CODE_POINTER(m_value);
}
template<PtrTag newTag>
MacroAssemblerCodePtr<newTag> retagged() const
{
if (!m_value)
return MacroAssemblerCodePtr<newTag>();
return MacroAssemblerCodePtr<newTag>::createFromExecutableAddress(retaggedExecutableAddress<newTag>());
}
template<typename T = void*>
T executableAddress() const
{
return bitwise_cast<T>(m_value);
}
template<typename T = void*>
T untaggedExecutableAddress() const
{
return untagCodePtr<T, tag>(m_value);
}
template<PtrTag newTag, typename T = void*>
T retaggedExecutableAddress() const
{
return retagCodePtr<T, tag, newTag>(m_value);
}
#if CPU(ARM_THUMB2)
// To use this pointer as a data address remove the decoration.
template<typename T = void*>
T dataLocation() const
{
ASSERT_VALID_CODE_POINTER(m_value);
return bitwise_cast<T>(m_value ? bitwise_cast<char*>(m_value) - 1 : nullptr);
}
#else
template<typename T = void*>
T dataLocation() const
{
ASSERT_VALID_CODE_POINTER(m_value);
return untagCodePtr<T, tag>(m_value);
}
#endif
bool operator!() const
{
return !m_value;
}
explicit operator bool() const { return !(!*this); }
bool operator==(const MacroAssemblerCodePtr& other) const
{
return m_value == other.m_value;
}
// Disallow any casting operations (except for booleans). Instead, the client
// should be asking executableAddress() explicitly.
template<typename T, typename = std::enable_if_t<!std::is_same<T, bool>::value>>
operator T() = delete;
void dumpWithName(const char* name, PrintStream& out) const
{
MacroAssemblerCodePtrBase::dumpWithName(executableAddress(), dataLocation(), name, out);
}
void dump(PrintStream& out) const { dumpWithName("CodePtr", out); }
enum EmptyValueTag { EmptyValue };
enum DeletedValueTag { DeletedValue };
MacroAssemblerCodePtr(EmptyValueTag)
: m_value(emptyValue())
{ }
MacroAssemblerCodePtr(DeletedValueTag)
: m_value(deletedValue())
{ }
bool isEmptyValue() const { return m_value == emptyValue(); }
bool isDeletedValue() const { return m_value == deletedValue(); }
unsigned hash() const { return PtrHash<const void*>::hash(m_value); }
static void initialize();
private:
static const void* emptyValue() { return bitwise_cast<void*>(static_cast<intptr_t>(1)); }
static const void* deletedValue() { return bitwise_cast<void*>(static_cast<intptr_t>(2)); }
const void* m_value { nullptr };
};
template<PtrTag tag>
struct MacroAssemblerCodePtrHash {
static unsigned hash(const MacroAssemblerCodePtr<tag>& ptr) { return ptr.hash(); }
static bool equal(const MacroAssemblerCodePtr<tag>& a, const MacroAssemblerCodePtr<tag>& b)
{
return a == b;
}
static constexpr bool safeToCompareToEmptyOrDeleted = true;
};
// MacroAssemblerCodeRef:
//
// A reference to a section of JIT generated code. A CodeRef consists of a
// pointer to the code, and a ref pointer to the pool from within which it
// was allocated.
class MacroAssemblerCodeRefBase {
protected:
static bool tryToDisassemble(MacroAssemblerCodePtr<DisassemblyPtrTag>, size_t, const char* prefix, PrintStream& out);
static bool tryToDisassemble(MacroAssemblerCodePtr<DisassemblyPtrTag>, size_t, const char* prefix);
JS_EXPORT_PRIVATE static CString disassembly(MacroAssemblerCodePtr<DisassemblyPtrTag>, size_t);
};
template<PtrTag tag>
class MacroAssemblerCodeRef : private MacroAssemblerCodeRefBase {
private:
// This is private because it's dangerous enough that we want uses of it
// to be easy to find - hence the static create method below.
explicit MacroAssemblerCodeRef(MacroAssemblerCodePtr<tag> codePtr)
: m_codePtr(codePtr)
{
ASSERT(m_codePtr);
}
public:
MacroAssemblerCodeRef() = default;
MacroAssemblerCodeRef(Ref<ExecutableMemoryHandle>&& executableMemory)
: m_codePtr(executableMemory->start().retaggedPtr<tag>())
, m_executableMemory(WTFMove(executableMemory))
{
ASSERT(m_executableMemory->isManaged());
ASSERT(m_executableMemory->start());
ASSERT(m_codePtr);
}
template<PtrTag otherTag>
MacroAssemblerCodeRef& operator=(const MacroAssemblerCodeRef<otherTag>& otherCodeRef)
{
m_codePtr = MacroAssemblerCodePtr<tag>::createFromExecutableAddress(otherCodeRef.code().template retaggedExecutableAddress<tag>());
m_executableMemory = otherCodeRef.m_executableMemory;
return *this;
}
// Use this only when you know that the codePtr refers to code that is
// already being kept alive through some other means. Typically this means
// that codePtr is immortal.
static MacroAssemblerCodeRef createSelfManagedCodeRef(MacroAssemblerCodePtr<tag> codePtr)
{
return MacroAssemblerCodeRef(codePtr);
}
ExecutableMemoryHandle* executableMemory() const
{
return m_executableMemory.get();
}
MacroAssemblerCodePtr<tag> code() const
{
return m_codePtr;
}
template<PtrTag newTag>
MacroAssemblerCodePtr<newTag> retaggedCode() const
{
return m_codePtr.template retagged<newTag>();
}
template<PtrTag newTag>
MacroAssemblerCodeRef<newTag> retagged() const
{
return MacroAssemblerCodeRef<newTag>(*this);
}
size_t size() const
{
if (!m_executableMemory)
return 0;
return m_executableMemory->sizeInBytes();
}
bool tryToDisassemble(PrintStream& out, const char* prefix = "") const
{
return tryToDisassemble(retaggedCode<DisassemblyPtrTag>(), size(), prefix, out);
}
bool tryToDisassemble(const char* prefix = "") const
{
return tryToDisassemble(retaggedCode<DisassemblyPtrTag>(), size(), prefix);
}
CString disassembly() const
{
return MacroAssemblerCodeRefBase::disassembly(retaggedCode<DisassemblyPtrTag>(), size());
}
explicit operator bool() const { return !!m_codePtr; }
void dump(PrintStream& out) const
{
m_codePtr.dumpWithName("CodeRef", out);
}
private:
template<PtrTag otherTag>
MacroAssemblerCodeRef(const MacroAssemblerCodeRef<otherTag>& otherCodeRef)
{
*this = otherCodeRef;
}
MacroAssemblerCodePtr<tag> m_codePtr;
RefPtr<ExecutableMemoryHandle> m_executableMemory;
template<PtrTag> friend class MacroAssemblerCodeRef;
};
template<PtrTag tag>
inline FunctionPtr<tag>::FunctionPtr(MacroAssemblerCodePtr<tag> ptr)
: m_value(ptr.executableAddress())
{
}
} // namespace JSC
namespace WTF {
template<typename T> struct DefaultHash;
template<JSC::PtrTag tag> struct DefaultHash<JSC::MacroAssemblerCodePtr<tag>> {
typedef JSC::MacroAssemblerCodePtrHash<tag> Hash;
};
template<typename T> struct HashTraits;
template<JSC::PtrTag tag> struct HashTraits<JSC::MacroAssemblerCodePtr<tag>> : public CustomHashTraits<JSC::MacroAssemblerCodePtr<tag>> { };
} // namespace WTF