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/*
* Copyright (C) 1999-2001 Harri Porten (porten@kde.org)
* Copyright (C) 2001 Peter Kelly (pmk@post.com)
* Copyright (C) 2003-2018 Apple Inc. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*
*/
#pragma once
#include "AbstractPC.h"
#include "CalleeBits.h"
#include "MacroAssemblerCodeRef.h"
#include "Register.h"
#include "StackVisitor.h"
#include "VM.h"
#include "VMEntryRecord.h"
namespace JSC {
class Arguments;
class ExecState;
class Interpreter;
class JSCallee;
class JSScope;
class SourceOrigin;
struct Instruction;
typedef ExecState CallFrame;
struct CallSiteIndex {
CallSiteIndex()
: m_bits(UINT_MAX)
{
}
explicit CallSiteIndex(uint32_t bits)
: m_bits(bits)
{ }
#if USE(JSVALUE32_64)
explicit CallSiteIndex(const Instruction* instruction)
: m_bits(bitwise_cast<uint32_t>(instruction))
{ }
#endif
explicit operator bool() const { return m_bits != UINT_MAX; }
bool operator==(const CallSiteIndex& other) const { return m_bits == other.m_bits; }
inline uint32_t bits() const { return m_bits; }
private:
uint32_t m_bits;
};
// arm64_32 expects caller frame and return pc to use 8 bytes
struct CallerFrameAndPC {
alignas(CPURegister) CallFrame* callerFrame;
alignas(CPURegister) const Instruction* returnPC;
static const int sizeInRegisters = 2 * sizeof(CPURegister) / sizeof(Register);
};
static_assert(CallerFrameAndPC::sizeInRegisters == sizeof(CallerFrameAndPC) / sizeof(Register), "CallerFrameAndPC::sizeInRegisters is incorrect.");
struct CallFrameSlot {
static const int codeBlock = CallerFrameAndPC::sizeInRegisters;
static const int callee = codeBlock + 1;
static const int argumentCount = callee + 1;
static const int thisArgument = argumentCount + 1;
static const int firstArgument = thisArgument + 1;
};
// Represents the current state of script execution.
// Passed as the first argument to most functions.
class ExecState : private Register {
public:
static const int headerSizeInRegisters = CallFrameSlot::argumentCount + 1;
// This function should only be called in very specific circumstances
// when you've guaranteed the callee can't be a Wasm callee, and can
// be an arbitrary JSValue. This function should basically never be used.
// Its only use right now is when we are making a call, and we're not
// yet sure if the callee is a cell. In general, a JS callee is guaranteed
// to be a cell, however, there is a brief window where we need to check
// to see if it's a cell, and if it's not, we throw an exception.
JSValue guaranteedJSValueCallee() const
{
ASSERT(!callee().isWasm());
return this[CallFrameSlot::callee].jsValue();
}
JSObject* jsCallee() const
{
ASSERT(!callee().isWasm());
return this[CallFrameSlot::callee].object();
}
CalleeBits callee() const { return CalleeBits(this[CallFrameSlot::callee].pointer()); }
SUPPRESS_ASAN CalleeBits unsafeCallee() const { return CalleeBits(this[CallFrameSlot::callee].asanUnsafePointer()); }
CodeBlock* codeBlock() const { return this[CallFrameSlot::codeBlock].Register::codeBlock(); }
CodeBlock** addressOfCodeBlock() const { return bitwise_cast<CodeBlock**>(this + CallFrameSlot::codeBlock); }
SUPPRESS_ASAN CodeBlock* unsafeCodeBlock() const { return this[CallFrameSlot::codeBlock].Register::asanUnsafeCodeBlock(); }
JSScope* scope(int scopeRegisterOffset) const
{
ASSERT(this[scopeRegisterOffset].Register::scope());
return this[scopeRegisterOffset].Register::scope();
}
JSGlobalObject* wasmAwareLexicalGlobalObject(VM&);
bool isAnyWasmCallee();
// Global object in which the currently executing code was defined.
// Differs from VM::vmEntryGlobalObject() during function calls across web browser frames.
JSGlobalObject* lexicalGlobalObject() const;
// Differs from lexicalGlobalObject because this will have DOM window shell rather than
// the actual DOM window, which can't be "this" for security reasons.
JSObject* globalThisValue() const;
VM& vm() const;
static CallFrame* create(Register* callFrameBase) { return static_cast<CallFrame*>(callFrameBase); }
Register* registers() { return this; }
const Register* registers() const { return this; }
CallFrame& operator=(const Register& r) { *static_cast<Register*>(this) = r; return *this; }
CallFrame* callerFrame() const { return static_cast<CallFrame*>(callerFrameOrEntryFrame()); }
void* callerFrameOrEntryFrame() const { return callerFrameAndPC().callerFrame; }
SUPPRESS_ASAN void* unsafeCallerFrameOrEntryFrame() const { return unsafeCallerFrameAndPC().callerFrame; }
CallFrame* unsafeCallerFrame(EntryFrame*&) const;
JS_EXPORT_PRIVATE CallFrame* callerFrame(EntryFrame*&) const;
JS_EXPORT_PRIVATE SourceOrigin callerSourceOrigin();
static ptrdiff_t callerFrameOffset() { return OBJECT_OFFSETOF(CallerFrameAndPC, callerFrame); }
ReturnAddressPtr returnPC() const { return ReturnAddressPtr(callerFrameAndPC().returnPC); }
bool hasReturnPC() const { return !!callerFrameAndPC().returnPC; }
void clearReturnPC() { callerFrameAndPC().returnPC = 0; }
static ptrdiff_t returnPCOffset() { return OBJECT_OFFSETOF(CallerFrameAndPC, returnPC); }
AbstractPC abstractReturnPC(VM& vm) { return AbstractPC(vm, this); }
bool callSiteBitsAreBytecodeOffset() const;
bool callSiteBitsAreCodeOriginIndex() const;
unsigned callSiteAsRawBits() const;
unsigned unsafeCallSiteAsRawBits() const;
CallSiteIndex callSiteIndex() const;
CallSiteIndex unsafeCallSiteIndex() const;
private:
unsigned callSiteBitsAsBytecodeOffset() const;
public:
// This will try to get you the bytecode offset, but you should be aware that
// this bytecode offset may be bogus in the presence of inlining. This will
// also return 0 if the call frame has no notion of bytecode offsets (for
// example if it's native code).
// https://bugs.webkit.org/show_bug.cgi?id=121754
unsigned bytecodeOffset();
// This will get you a CodeOrigin. It will always succeed. May return
// CodeOrigin(0) if we're in native code.
JS_EXPORT_PRIVATE CodeOrigin codeOrigin();
Register* topOfFrame()
{
if (!codeBlock())
return registers();
return topOfFrameInternal();
}
const Instruction* currentVPC() const; // This only makes sense in the LLInt and baseline.
void setCurrentVPC(const Instruction*);
void setCallerFrame(CallFrame* frame) { callerFrameAndPC().callerFrame = frame; }
void setScope(int scopeRegisterOffset, JSScope* scope) { static_cast<Register*>(this)[scopeRegisterOffset] = scope; }
static void initGlobalExec(ExecState* globalExec, JSCallee* globalCallee);
// Read a register from the codeframe (or constant from the CodeBlock).
Register& r(int);
Register& r(VirtualRegister);
// Read a register for a non-constant
Register& uncheckedR(int);
Register& uncheckedR(VirtualRegister);
// Access to arguments as passed. (After capture, arguments may move to a different location.)
size_t argumentCount() const { return argumentCountIncludingThis() - 1; }
size_t argumentCountIncludingThis() const { return this[CallFrameSlot::argumentCount].payload(); }
static int argumentOffset(int argument) { return (CallFrameSlot::firstArgument + argument); }
static int argumentOffsetIncludingThis(int argument) { return (CallFrameSlot::thisArgument + argument); }
// In the following (argument() and setArgument()), the 'argument'
// parameter is the index of the arguments of the target function of
// this frame. The index starts at 0 for the first arg, 1 for the
// second, etc.
//
// The arguments (in this case) do not include the 'this' value.
// arguments(0) will not fetch the 'this' value. To get/set 'this',
// use thisValue() and setThisValue() below.
JSValue* addressOfArgumentsStart() const { return bitwise_cast<JSValue*>(this + argumentOffset(0)); }
JSValue argument(size_t argument)
{
if (argument >= argumentCount())
return jsUndefined();
return getArgumentUnsafe(argument);
}
JSValue uncheckedArgument(size_t argument)
{
ASSERT(argument < argumentCount());
return getArgumentUnsafe(argument);
}
void setArgument(size_t argument, JSValue value)
{
this[argumentOffset(argument)] = value;
}
JSValue getArgumentUnsafe(size_t argIndex)
{
// User beware! This method does not verify that there is a valid
// argument at the specified argIndex. This is used for debugging
// and verification code only. The caller is expected to know what
// he/she is doing when calling this method.
return this[argumentOffset(argIndex)].jsValue();
}
static int thisArgumentOffset() { return argumentOffsetIncludingThis(0); }
JSValue thisValue() { return this[thisArgumentOffset()].jsValue(); }
void setThisValue(JSValue value) { this[thisArgumentOffset()] = value; }
// Under the constructor implemented in C++, thisValue holds the newTarget instead of the automatically constructed value.
// The result of this function is only effective under the "construct" context.
JSValue newTarget() { return thisValue(); }
JSValue argumentAfterCapture(size_t argument);
static int offsetFor(size_t argumentCountIncludingThis) { return argumentCountIncludingThis + CallFrameSlot::thisArgument - 1; }
static CallFrame* noCaller() { return nullptr; }
bool isGlobalExec() const
{
return callerFrameAndPC().callerFrame == noCaller() && callerFrameAndPC().returnPC == nullptr;
}
void convertToStackOverflowFrame(VM&, CodeBlock* codeBlockToKeepAliveUntilFrameIsUnwound);
bool isStackOverflowFrame() const;
bool isWasmFrame() const;
void setArgumentCountIncludingThis(int count) { static_cast<Register*>(this)[CallFrameSlot::argumentCount].payload() = count; }
void setCallee(JSObject* callee) { static_cast<Register*>(this)[CallFrameSlot::callee] = callee; }
void setCodeBlock(CodeBlock* codeBlock) { static_cast<Register*>(this)[CallFrameSlot::codeBlock] = codeBlock; }
void setReturnPC(void* value) { callerFrameAndPC().returnPC = reinterpret_cast<const Instruction*>(value); }
String friendlyFunctionName();
// CallFrame::iterate() expects a Functor that implements the following method:
// StackVisitor::Status operator()(StackVisitor&) const;
// FIXME: This method is improper. We rely on the fact that we can call it with a null
// receiver. We should always be using StackVisitor directly.
// It's only valid to call this from a non-wasm top frame.
template <StackVisitor::EmptyEntryFrameAction action = StackVisitor::ContinueIfTopEntryFrameIsEmpty, typename Functor> void iterate(const Functor& functor)
{
VM* vm;
void* rawThis = this;
if (!!rawThis) {
RELEASE_ASSERT(callee().isCell());
vm = &this->vm();
} else
vm = nullptr;
StackVisitor::visit<action, Functor>(this, vm, functor);
}
void dump(PrintStream&);
JS_EXPORT_PRIVATE const char* describeFrame();
private:
ExecState();
~ExecState();
Register* topOfFrameInternal();
// The following are for internal use in debugging and verification
// code only and not meant as an API for general usage:
size_t argIndexForRegister(Register* reg)
{
// The register at 'offset' number of slots from the frame pointer
// i.e.
// reg = frame[offset];
// ==> reg = frame + offset;
// ==> offset = reg - frame;
int offset = reg - this->registers();
// The offset is defined (based on argumentOffset()) to be:
// offset = CallFrameSlot::firstArgument - argIndex;
// Hence:
// argIndex = CallFrameSlot::firstArgument - offset;
size_t argIndex = offset - CallFrameSlot::firstArgument;
return argIndex;
}
CallerFrameAndPC& callerFrameAndPC() { return *reinterpret_cast<CallerFrameAndPC*>(this); }
const CallerFrameAndPC& callerFrameAndPC() const { return *reinterpret_cast<const CallerFrameAndPC*>(this); }
SUPPRESS_ASAN const CallerFrameAndPC& unsafeCallerFrameAndPC() const { return *reinterpret_cast<const CallerFrameAndPC*>(this); }
};
} // namespace JSC