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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#ifndef jit_BaselineFrameInfo_h
#define jit_BaselineFrameInfo_h
#include "mozilla/Attributes.h"
#include "mozilla/Maybe.h"
#include <new>
#include "jit/BaselineFrame.h"
#include "jit/BaselineJIT.h"
#include "jit/FixedList.h"
#include "jit/MacroAssembler.h"
#include "jit/SharedICRegisters.h"
namespace js {
namespace jit {
struct BytecodeInfo;
class MacroAssembler;
// [SMDOC] Baseline FrameInfo overview.
//
// FrameInfo is used by BaselineCodeGen to track values stored in the frame.
// There are two implementations:
//
// InterpreterFrameInfo
// --------------------
// The InterpreterFrameInfo class is used by the interpreter generator and is
// a very simple interface on top of the MacroAssembler, because the stack is
// always synced.
//
// CompilerFrameInfo
// -----------------
// The CompilerFrameInfo class is more complicated because it maintains a
// virtual stack to optimize some common stack operations. Locals and arguments
// are always fully synced. Stack values can either be synced, stored as
// constant, stored in a Value register or refer to a local slot. Syncing a
// StackValue ensures it's stored on the stack, e.g. kind == Stack.
//
// To see how this works, consider the following statement:
//
// var y = x + 9;
//
// Here two values are pushed: StackValue(LocalSlot(0)) and
// StackValue(Int32Value(9)). Only when we reach the ADD op, code is generated
// to load the operands directly into the right operand registers and sync all
// other stack values.
//
// For stack values, the following invariants hold (and are checked between
// ops):
//
// (1) If a value is synced (kind == Stack), all values below it must also be
// synced. In other words, values with kind other than Stack can only appear
// on top of the abstract stack.
//
// (2) When we call a stub or IC, all values still on the stack must be synced.
// Represents a value pushed on the stack. Note that StackValue is not used for
// locals or arguments since these are always fully synced.
class StackValue {
public:
enum Kind {
Constant,
Register,
Stack,
LocalSlot,
ArgSlot,
ThisSlot,
#ifdef DEBUG
// In debug builds, assert Kind is initialized.
Uninitialized,
#endif
};
private:
MOZ_INIT_OUTSIDE_CTOR Kind kind_;
MOZ_INIT_OUTSIDE_CTOR union Data {
JS::Value constant;
ValueOperand reg;
uint32_t localSlot;
uint32_t argSlot;
// |constant| has a non-trivial constructor and therefore MUST be
// placement-new'd into existence.
MOZ_PUSH_DISABLE_NONTRIVIAL_UNION_WARNINGS
Data() {}
MOZ_POP_DISABLE_NONTRIVIAL_UNION_WARNINGS
} data;
MOZ_INIT_OUTSIDE_CTOR JSValueType knownType_;
public:
StackValue() { reset(); }
Kind kind() const { return kind_; }
bool hasKnownType() const { return knownType_ != JSVAL_TYPE_UNKNOWN; }
bool hasKnownType(JSValueType type) const {
MOZ_ASSERT(type != JSVAL_TYPE_UNKNOWN);
return knownType_ == type;
}
JSValueType knownType() const {
MOZ_ASSERT(hasKnownType());
return knownType_;
}
void reset() {
#ifdef DEBUG
kind_ = Uninitialized;
knownType_ = JSVAL_TYPE_UNKNOWN;
#endif
}
Value constant() const {
MOZ_ASSERT(kind_ == Constant);
return data.constant;
}
ValueOperand reg() const {
MOZ_ASSERT(kind_ == Register);
return data.reg;
}
uint32_t localSlot() const {
MOZ_ASSERT(kind_ == LocalSlot);
return data.localSlot;
}
uint32_t argSlot() const {
MOZ_ASSERT(kind_ == ArgSlot);
return data.argSlot;
}
void setConstant(const Value& v) {
kind_ = Constant;
new (&data.constant) Value(v);
knownType_ = v.isDouble() ? JSVAL_TYPE_DOUBLE : v.extractNonDoubleType();
}
void setRegister(const ValueOperand& val,
JSValueType knownType = JSVAL_TYPE_UNKNOWN) {
kind_ = Register;
new (&data.reg) ValueOperand(val);
knownType_ = knownType;
}
void setLocalSlot(uint32_t slot) {
kind_ = LocalSlot;
new (&data.localSlot) uint32_t(slot);
knownType_ = JSVAL_TYPE_UNKNOWN;
}
void setArgSlot(uint32_t slot) {
kind_ = ArgSlot;
new (&data.argSlot) uint32_t(slot);
knownType_ = JSVAL_TYPE_UNKNOWN;
}
void setThis() {
kind_ = ThisSlot;
knownType_ = JSVAL_TYPE_UNKNOWN;
}
void setStack() {
kind_ = Stack;
knownType_ = JSVAL_TYPE_UNKNOWN;
}
};
enum StackAdjustment { AdjustStack, DontAdjustStack };
class FrameInfo {
protected:
MacroAssembler& masm;
public:
explicit FrameInfo(MacroAssembler& masm) : masm(masm) {}
Address addressOfLocal(size_t local) const {
return Address(FramePointer, BaselineFrame::reverseOffsetOfLocal(local));
}
Address addressOfArg(size_t arg) const {
return Address(FramePointer, JitFrameLayout::offsetOfActualArg(arg));
}
Address addressOfThis() const {
return Address(FramePointer, JitFrameLayout::offsetOfThis());
}
Address addressOfCalleeToken() const {
return Address(FramePointer, JitFrameLayout::offsetOfCalleeToken());
}
Address addressOfEnvironmentChain() const {
return Address(FramePointer,
BaselineFrame::reverseOffsetOfEnvironmentChain());
}
Address addressOfICScript() const {
return Address(FramePointer, BaselineFrame::reverseOffsetOfICScript());
}
Address addressOfFlags() const {
return Address(FramePointer, BaselineFrame::reverseOffsetOfFlags());
}
Address addressOfReturnValue() const {
return Address(FramePointer, BaselineFrame::reverseOffsetOfReturnValue());
}
Address addressOfArgsObj() const {
return Address(FramePointer, BaselineFrame::reverseOffsetOfArgsObj());
}
Address addressOfScratchValue() const {
return Address(FramePointer, BaselineFrame::reverseOffsetOfScratchValue());
}
Address addressOfScratchValueLow32() const {
return Address(FramePointer,
BaselineFrame::reverseOffsetOfScratchValueLow32());
}
Address addressOfScratchValueHigh32() const {
return Address(FramePointer,
BaselineFrame::reverseOffsetOfScratchValueHigh32());
}
#ifdef DEBUG
Address addressOfDebugFrameSize() const {
return Address(FramePointer,
BaselineFrame::reverseOffsetOfDebugFrameSize());
}
#endif
};
class CompilerFrameInfo : public FrameInfo {
friend class BaselinePerfSpewer;
JSScript* script;
FixedList<StackValue> stack;
size_t spIndex;
public:
CompilerFrameInfo(JSScript* script, MacroAssembler& masm)
: FrameInfo(masm), script(script), spIndex(0) {}
[[nodiscard]] bool init(TempAllocator& alloc);
size_t nlocals() const { return script->nfixed(); }
size_t nargs() const { return script->function()->nargs(); }
private:
inline StackValue* rawPush() {
StackValue* val = &stack[spIndex++];
val->reset();
return val;
}
inline StackValue* peek(int32_t index) const {
MOZ_ASSERT(index < 0);
return const_cast<StackValue*>(&stack[spIndex + index]);
}
public:
inline size_t stackDepth() const { return spIndex; }
inline void setStackDepth(uint32_t newDepth) {
if (newDepth <= stackDepth()) {
spIndex = newDepth;
} else {
uint32_t diff = newDepth - stackDepth();
for (uint32_t i = 0; i < diff; i++) {
StackValue* val = rawPush();
val->setStack();
}
MOZ_ASSERT(spIndex == newDepth);
}
}
void assertStackDepth(uint32_t depth) { MOZ_ASSERT(stackDepth() == depth); }
void incStackDepth(int32_t diff) { setStackDepth(stackDepth() + diff); }
bool hasKnownStackDepth(uint32_t depth) { return stackDepth() == depth; }
inline void pop(StackAdjustment adjust = AdjustStack);
inline void popn(uint32_t n, StackAdjustment adjust = AdjustStack);
inline void push(const Value& val) {
StackValue* sv = rawPush();
sv->setConstant(val);
}
inline void push(const ValueOperand& val,
JSValueType knownType = JSVAL_TYPE_UNKNOWN) {
StackValue* sv = rawPush();
sv->setRegister(val, knownType);
}
inline void pushLocal(uint32_t local) {
MOZ_ASSERT(local < nlocals());
StackValue* sv = rawPush();
sv->setLocalSlot(local);
}
inline void pushArg(uint32_t arg) {
StackValue* sv = rawPush();
sv->setArgSlot(arg);
}
inline void pushThis() {
StackValue* sv = rawPush();
sv->setThis();
}
inline void pushScratchValue() {
masm.pushValue(addressOfScratchValue());
StackValue* sv = rawPush();
sv->setStack();
}
Address addressOfLocal(size_t local) const {
MOZ_ASSERT(local < nlocals());
return FrameInfo::addressOfLocal(local);
}
Address addressOfArg(size_t arg) const {
MOZ_ASSERT(arg < nargs());
return FrameInfo::addressOfArg(arg);
}
Address addressOfStackValue(int32_t depth) const {
const StackValue* value = peek(depth);
MOZ_ASSERT(value->kind() == StackValue::Stack);
size_t slot = value - &stack[0];
MOZ_ASSERT(slot < stackDepth());
return Address(FramePointer,
BaselineFrame::reverseOffsetOfLocal(nlocals() + slot));
}
void popValue(ValueOperand dest);
void sync(StackValue* val);
void syncStack(uint32_t uses);
uint32_t numUnsyncedSlots();
void popRegsAndSync(uint32_t uses);
void assertSyncedStack() const {
MOZ_ASSERT_IF(stackDepth() > 0, peek(-1)->kind() == StackValue::Stack);
}
bool stackValueHasKnownType(int32_t depth, JSValueType type) const {
return peek(depth)->hasKnownType(type);
}
mozilla::Maybe<Value> knownStackValue(int32_t depth) const {
StackValue* val = peek(depth);
if (val->kind() == StackValue::Constant) {
return mozilla::Some(val->constant());
}
return mozilla::Nothing();
}
void storeStackValue(int32_t depth, const Address& dest,
const ValueOperand& scratch);
uint32_t frameSize() const {
return BaselineFrame::frameSizeForNumValueSlots(nlocals() + stackDepth());
}
#ifdef DEBUG
// Assert the state is valid before excuting "pc".
void assertValidState(const BytecodeInfo& info);
#else
inline void assertValidState(const BytecodeInfo& info) {}
#endif
};
class InterpreterFrameInfo : public FrameInfo {
public:
explicit InterpreterFrameInfo(MacroAssembler& masm) : FrameInfo(masm) {}
// These methods are no-ops in the interpreter, because we don't have a
// virtual stack there.
void syncStack(uint32_t uses) {}
void assertSyncedStack() const {}
void assertStackDepth(uint32_t depth) {}
void incStackDepth(int32_t diff) {}
bool hasKnownStackDepth(uint32_t depth) { return false; }
uint32_t numUnsyncedSlots() { return 0; }
bool stackValueHasKnownType(int32_t depth, JSValueType type) const {
return false;
}
mozilla::Maybe<Value> knownStackValue(int32_t depth) const {
return mozilla::Nothing();
}
Address addressOfStackValue(int depth) const {
MOZ_ASSERT(depth < 0);
return Address(masm.getStackPointer(),
masm.framePushed() + size_t(-(depth + 1)) * sizeof(Value));
}
BaseIndex addressOfStackValue(Register index, int32_t offset = 0) const {
return BaseIndex(masm.getStackPointer(), index, ValueScale, offset);
}
void popRegsAndSync(uint32_t uses);
inline void pop();
inline void popn(uint32_t n);
void popn(Register reg) {
// sp := sp + reg * sizeof(Value)
Register spReg = AsRegister(masm.getStackPointer());
masm.computeEffectiveAddress(BaseValueIndex(spReg, reg), spReg);
// On arm64, SP may be < PSP now (that's OK).
// eg testcase: tests/arguments/strict-args-generator-flushstack.js
}
void popValue(ValueOperand dest) { masm.popValue(dest); }
void push(const ValueOperand& val,
JSValueType knownType = JSVAL_TYPE_UNKNOWN) {
masm.pushValue(val);
}
void push(const Value& val) { masm.pushValue(val); }
void pushThis() { masm.pushValue(addressOfThis()); }
void pushScratchValue() { masm.pushValue(addressOfScratchValue()); }
void storeStackValue(int32_t depth, const Address& dest,
const ValueOperand& scratch) {
masm.loadValue(addressOfStackValue(depth), scratch);
masm.storeValue(scratch, dest);
}
void bumpInterpreterICEntry();
Address addressOfInterpreterScript() const {
return Address(FramePointer,
BaselineFrame::reverseOffsetOfInterpreterScript());
}
Address addressOfInterpreterPC() const {
return Address(FramePointer, BaselineFrame::reverseOffsetOfInterpreterPC());
}
Address addressOfInterpreterICEntry() const {
return Address(FramePointer,
BaselineFrame::reverseOffsetOfInterpreterICEntry());
}
};
} // namespace jit
} // namespace js
#endif /* jit_BaselineFrameInfo_h */