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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: set ts=8 sts=4 et sw=4 tw=99:
+ * 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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef jit_Snapshot_h
+#define jit_Snapshot_h
+
+#include "mozilla/Alignment.h"
+
+#include "jsalloc.h"
+#include "jsbytecode.h"
+
+#include "jit/CompactBuffer.h"
+#include "jit/IonTypes.h"
+#include "jit/Registers.h"
+
+#include "js/HashTable.h"
+
+namespace js {
+class GenericPrinter;
+
+namespace jit {
+
+class RValueAllocation;
+
+// A Recover Value Allocation mirror what is known at compiled time as being the
+// MIRType and the LAllocation. This is read out of the snapshot to recover the
+// value which would be there if this frame was an interpreter frame instead of
+// an Ion frame.
+//
+// It is used with the SnapshotIterator to recover a Value from the stack,
+// spilled registers or the list of constant of the compiled script.
+//
+// Unit tests are located in jsapi-tests/testJitRValueAlloc.cpp.
+class RValueAllocation
+{
+ public:
+
+ // See RValueAllocation encoding in Snapshots.cpp
+ enum Mode
+ {
+ CONSTANT = 0x00,
+ CST_UNDEFINED = 0x01,
+ CST_NULL = 0x02,
+ DOUBLE_REG = 0x03,
+ ANY_FLOAT_REG = 0x04,
+ ANY_FLOAT_STACK = 0x05,
+#if defined(JS_NUNBOX32)
+ UNTYPED_REG_REG = 0x06,
+ UNTYPED_REG_STACK = 0x07,
+ UNTYPED_STACK_REG = 0x08,
+ UNTYPED_STACK_STACK = 0x09,
+#elif defined(JS_PUNBOX64)
+ UNTYPED_REG = 0x06,
+ UNTYPED_STACK = 0x07,
+#endif
+
+ // Recover instructions.
+ RECOVER_INSTRUCTION = 0x0a,
+ RI_WITH_DEFAULT_CST = 0x0b,
+
+ // The JSValueType is packed in the Mode.
+ TYPED_REG_MIN = 0x10,
+ TYPED_REG_MAX = 0x1f,
+ TYPED_REG = TYPED_REG_MIN,
+
+ // The JSValueType is packed in the Mode.
+ TYPED_STACK_MIN = 0x20,
+ TYPED_STACK_MAX = 0x2f,
+ TYPED_STACK = TYPED_STACK_MIN,
+
+ // This mask can be used with any other valid mode. When this flag is
+ // set on the mode, this inform the snapshot iterator that even if the
+ // allocation is readable, the content of if might be incomplete unless
+ // all side-effects are executed.
+ RECOVER_SIDE_EFFECT_MASK = 0x80,
+
+ // This mask represents the set of bits which can be used to encode a
+ // value in a snapshot. The mode is used to determine how to interpret
+ // the union of values and how to pack the value in memory.
+ MODE_BITS_MASK = 0x17f,
+
+ INVALID = 0x100,
+ };
+
+ enum { PACKED_TAG_MASK = 0x0f };
+
+ // See Payload encoding in Snapshots.cpp
+ enum PayloadType {
+ PAYLOAD_NONE,
+ PAYLOAD_INDEX,
+ PAYLOAD_STACK_OFFSET,
+ PAYLOAD_GPR,
+ PAYLOAD_FPU,
+ PAYLOAD_PACKED_TAG
+ };
+
+ struct Layout {
+ PayloadType type1;
+ PayloadType type2;
+ const char* name;
+ };
+
+ private:
+ Mode mode_;
+
+ // Additional information to recover the content of the allocation.
+ struct FloatRegisterBits {
+ uint32_t data;
+ bool operator == (const FloatRegisterBits& other) const {
+ return data == other.data;
+ }
+ uint32_t code() const {
+ return data;
+ }
+ const char* name() const {
+ FloatRegister tmp = FloatRegister::FromCode(data);
+ return tmp.name();
+ }
+ };
+
+ union Payload {
+ uint32_t index;
+ int32_t stackOffset;
+ Register gpr;
+ FloatRegisterBits fpu;
+ JSValueType type;
+ };
+
+ Payload arg1_;
+ Payload arg2_;
+
+ static Payload payloadOfIndex(uint32_t index) {
+ Payload p;
+ p.index = index;
+ return p;
+ }
+ static Payload payloadOfStackOffset(int32_t offset) {
+ Payload p;
+ p.stackOffset = offset;
+ return p;
+ }
+ static Payload payloadOfRegister(Register reg) {
+ Payload p;
+ p.gpr = reg;
+ return p;
+ }
+ static Payload payloadOfFloatRegister(FloatRegister reg) {
+ Payload p;
+ FloatRegisterBits b;
+ b.data = reg.code();
+ p.fpu = b;
+ return p;
+ }
+ static Payload payloadOfValueType(JSValueType type) {
+ Payload p;
+ p.type = type;
+ return p;
+ }
+
+ static const Layout& layoutFromMode(Mode mode);
+
+ static void readPayload(CompactBufferReader& reader, PayloadType t,
+ uint8_t* mode, Payload* p);
+ static void writePayload(CompactBufferWriter& writer, PayloadType t,
+ Payload p);
+ static void writePadding(CompactBufferWriter& writer);
+ static void dumpPayload(GenericPrinter& out, PayloadType t, Payload p);
+ static bool equalPayloads(PayloadType t, Payload lhs, Payload rhs);
+
+ RValueAllocation(Mode mode, Payload a1, Payload a2)
+ : mode_(mode),
+ arg1_(a1),
+ arg2_(a2)
+ {
+ }
+
+ RValueAllocation(Mode mode, Payload a1)
+ : mode_(mode),
+ arg1_(a1)
+ {
+ }
+
+ explicit RValueAllocation(Mode mode)
+ : mode_(mode)
+ {
+ }
+
+ public:
+ RValueAllocation()
+ : mode_(INVALID)
+ { }
+
+ // DOUBLE_REG
+ static RValueAllocation Double(FloatRegister reg) {
+ return RValueAllocation(DOUBLE_REG, payloadOfFloatRegister(reg));
+ }
+
+ // ANY_FLOAT_REG or ANY_FLOAT_STACK
+ static RValueAllocation AnyFloat(FloatRegister reg) {
+ return RValueAllocation(ANY_FLOAT_REG, payloadOfFloatRegister(reg));
+ }
+ static RValueAllocation AnyFloat(int32_t offset) {
+ return RValueAllocation(ANY_FLOAT_STACK, payloadOfStackOffset(offset));
+ }
+
+ // TYPED_REG or TYPED_STACK
+ static RValueAllocation Typed(JSValueType type, Register reg) {
+ MOZ_ASSERT(type != JSVAL_TYPE_DOUBLE &&
+ type != JSVAL_TYPE_MAGIC &&
+ type != JSVAL_TYPE_NULL &&
+ type != JSVAL_TYPE_UNDEFINED);
+ return RValueAllocation(TYPED_REG, payloadOfValueType(type),
+ payloadOfRegister(reg));
+ }
+ static RValueAllocation Typed(JSValueType type, int32_t offset) {
+ MOZ_ASSERT(type != JSVAL_TYPE_MAGIC &&
+ type != JSVAL_TYPE_NULL &&
+ type != JSVAL_TYPE_UNDEFINED);
+ return RValueAllocation(TYPED_STACK, payloadOfValueType(type),
+ payloadOfStackOffset(offset));
+ }
+
+ // UNTYPED
+#if defined(JS_NUNBOX32)
+ static RValueAllocation Untyped(Register type, Register payload) {
+ return RValueAllocation(UNTYPED_REG_REG,
+ payloadOfRegister(type),
+ payloadOfRegister(payload));
+ }
+
+ static RValueAllocation Untyped(Register type, int32_t payloadStackOffset) {
+ return RValueAllocation(UNTYPED_REG_STACK,
+ payloadOfRegister(type),
+ payloadOfStackOffset(payloadStackOffset));
+ }
+
+ static RValueAllocation Untyped(int32_t typeStackOffset, Register payload) {
+ return RValueAllocation(UNTYPED_STACK_REG,
+ payloadOfStackOffset(typeStackOffset),
+ payloadOfRegister(payload));
+ }
+
+ static RValueAllocation Untyped(int32_t typeStackOffset, int32_t payloadStackOffset) {
+ return RValueAllocation(UNTYPED_STACK_STACK,
+ payloadOfStackOffset(typeStackOffset),
+ payloadOfStackOffset(payloadStackOffset));
+ }
+
+#elif defined(JS_PUNBOX64)
+ static RValueAllocation Untyped(Register reg) {
+ return RValueAllocation(UNTYPED_REG, payloadOfRegister(reg));
+ }
+
+ static RValueAllocation Untyped(int32_t stackOffset) {
+ return RValueAllocation(UNTYPED_STACK, payloadOfStackOffset(stackOffset));
+ }
+#endif
+
+ // common constants.
+ static RValueAllocation Undefined() {
+ return RValueAllocation(CST_UNDEFINED);
+ }
+ static RValueAllocation Null() {
+ return RValueAllocation(CST_NULL);
+ }
+
+ // CONSTANT's index
+ static RValueAllocation ConstantPool(uint32_t index) {
+ return RValueAllocation(CONSTANT, payloadOfIndex(index));
+ }
+
+ // Recover instruction's index
+ static RValueAllocation RecoverInstruction(uint32_t index) {
+ return RValueAllocation(RECOVER_INSTRUCTION, payloadOfIndex(index));
+ }
+ static RValueAllocation RecoverInstruction(uint32_t riIndex, uint32_t cstIndex) {
+ return RValueAllocation(RI_WITH_DEFAULT_CST,
+ payloadOfIndex(riIndex),
+ payloadOfIndex(cstIndex));
+ }
+
+ void setNeedSideEffect() {
+ MOZ_ASSERT(!needSideEffect() && mode_ != INVALID);
+ mode_ = Mode(mode_ | RECOVER_SIDE_EFFECT_MASK);
+ }
+
+ void writeHeader(CompactBufferWriter& writer, JSValueType type, uint32_t regCode) const;
+ public:
+ static RValueAllocation read(CompactBufferReader& reader);
+ void write(CompactBufferWriter& writer) const;
+
+ public:
+ Mode mode() const {
+ return Mode(mode_ & MODE_BITS_MASK);
+ }
+ bool needSideEffect() const {
+ return mode_ & RECOVER_SIDE_EFFECT_MASK;
+ }
+
+ uint32_t index() const {
+ MOZ_ASSERT(layoutFromMode(mode()).type1 == PAYLOAD_INDEX);
+ return arg1_.index;
+ }
+ int32_t stackOffset() const {
+ MOZ_ASSERT(layoutFromMode(mode()).type1 == PAYLOAD_STACK_OFFSET);
+ return arg1_.stackOffset;
+ }
+ Register reg() const {
+ MOZ_ASSERT(layoutFromMode(mode()).type1 == PAYLOAD_GPR);
+ return arg1_.gpr;
+ }
+ FloatRegister fpuReg() const {
+ MOZ_ASSERT(layoutFromMode(mode()).type1 == PAYLOAD_FPU);
+ FloatRegisterBits b = arg1_.fpu;
+ return FloatRegister::FromCode(b.data);
+ }
+ JSValueType knownType() const {
+ MOZ_ASSERT(layoutFromMode(mode()).type1 == PAYLOAD_PACKED_TAG);
+ return arg1_.type;
+ }
+
+ uint32_t index2() const {
+ MOZ_ASSERT(layoutFromMode(mode()).type2 == PAYLOAD_INDEX);
+ return arg2_.index;
+ }
+ int32_t stackOffset2() const {
+ MOZ_ASSERT(layoutFromMode(mode()).type2 == PAYLOAD_STACK_OFFSET);
+ return arg2_.stackOffset;
+ }
+ Register reg2() const {
+ MOZ_ASSERT(layoutFromMode(mode()).type2 == PAYLOAD_GPR);
+ return arg2_.gpr;
+ }
+
+ public:
+ void dump(GenericPrinter& out) const;
+
+ public:
+ bool operator==(const RValueAllocation& rhs) const {
+ if (mode_ != rhs.mode_)
+ return false;
+
+ const Layout& layout = layoutFromMode(mode());
+ return equalPayloads(layout.type1, arg1_, rhs.arg1_) &&
+ equalPayloads(layout.type2, arg2_, rhs.arg2_);
+ }
+
+ HashNumber hash() const;
+
+ struct Hasher
+ {
+ typedef RValueAllocation Key;
+ typedef Key Lookup;
+ static HashNumber hash(const Lookup& v) {
+ return v.hash();
+ }
+ static bool match(const Key& k, const Lookup& l) {
+ return k == l;
+ }
+ };
+};
+
+class RecoverWriter;
+
+// Collects snapshots in a contiguous buffer, which is copied into IonScript
+// memory after code generation.
+class SnapshotWriter
+{
+ CompactBufferWriter writer_;
+ CompactBufferWriter allocWriter_;
+
+ // Map RValueAllocations to an offset in the allocWriter_ buffer. This is
+ // useful as value allocations are repeated frequently.
+ typedef RValueAllocation RVA;
+ typedef HashMap<RVA, uint32_t, RVA::Hasher, SystemAllocPolicy> RValueAllocMap;
+ RValueAllocMap allocMap_;
+
+ // This is only used to assert sanity.
+ uint32_t allocWritten_;
+
+ // Used to report size of the snapshot in the spew messages.
+ SnapshotOffset lastStart_;
+
+ public:
+ MOZ_MUST_USE bool init();
+
+ SnapshotOffset startSnapshot(RecoverOffset recoverOffset, BailoutKind kind);
+#ifdef TRACK_SNAPSHOTS
+ void trackSnapshot(uint32_t pcOpcode, uint32_t mirOpcode, uint32_t mirId,
+ uint32_t lirOpcode, uint32_t lirId);
+#endif
+ MOZ_MUST_USE bool add(const RValueAllocation& slot);
+
+ uint32_t allocWritten() const {
+ return allocWritten_;
+ }
+ void endSnapshot();
+
+ bool oom() const {
+ return writer_.oom() || writer_.length() >= MAX_BUFFER_SIZE ||
+ allocWriter_.oom() || allocWriter_.length() >= MAX_BUFFER_SIZE;
+ }
+
+ size_t listSize() const {
+ return writer_.length();
+ }
+ const uint8_t* listBuffer() const {
+ return writer_.buffer();
+ }
+
+ size_t RVATableSize() const {
+ return allocWriter_.length();
+ }
+ const uint8_t* RVATableBuffer() const {
+ return allocWriter_.buffer();
+ }
+};
+
+class MNode;
+
+class RecoverWriter
+{
+ CompactBufferWriter writer_;
+
+ uint32_t instructionCount_;
+ uint32_t instructionsWritten_;
+
+ public:
+ SnapshotOffset startRecover(uint32_t instructionCount, bool resumeAfter);
+
+ void writeInstruction(const MNode* rp);
+
+ void endRecover();
+
+ size_t size() const {
+ return writer_.length();
+ }
+ const uint8_t* buffer() const {
+ return writer_.buffer();
+ }
+
+ bool oom() const {
+ return writer_.oom() || writer_.length() >= MAX_BUFFER_SIZE;
+ }
+};
+
+class RecoverReader;
+
+// A snapshot reader reads the entries out of the compressed snapshot buffer in
+// a script. These entries describe the equivalent interpreter frames at a given
+// position in JIT code. Each entry is an Ion's value allocations, used to
+// recover the corresponding Value from an Ion frame.
+class SnapshotReader
+{
+ CompactBufferReader reader_;
+ CompactBufferReader allocReader_;
+ const uint8_t* allocTable_;
+
+ BailoutKind bailoutKind_;
+ uint32_t allocRead_; // Number of slots that have been read.
+ RecoverOffset recoverOffset_; // Offset of the recover instructions.
+
+#ifdef TRACK_SNAPSHOTS
+ private:
+ uint32_t pcOpcode_;
+ uint32_t mirOpcode_;
+ uint32_t mirId_;
+ uint32_t lirOpcode_;
+ uint32_t lirId_;
+
+ public:
+ void readTrackSnapshot();
+ void spewBailingFrom() const;
+#endif
+
+ private:
+ void readSnapshotHeader();
+ uint32_t readAllocationIndex();
+
+ public:
+ SnapshotReader(const uint8_t* snapshots, uint32_t offset,
+ uint32_t RVATableSize, uint32_t listSize);
+
+ RValueAllocation readAllocation();
+ void skipAllocation() {
+ readAllocationIndex();
+ }
+
+ BailoutKind bailoutKind() const {
+ return bailoutKind_;
+ }
+ RecoverOffset recoverOffset() const {
+ return recoverOffset_;
+ }
+
+ uint32_t numAllocationsRead() const {
+ return allocRead_;
+ }
+ void resetNumAllocationsRead() {
+ allocRead_ = 0;
+ }
+};
+
+class RInstructionStorage
+{
+ static const size_t Size = 4 * sizeof(uint32_t);
+ mozilla::AlignedStorage<Size> mem;
+
+ public:
+ const void* addr() const { return mem.addr(); }
+ void* addr() { return mem.addr(); }
+
+ RInstructionStorage() = default;
+
+ RInstructionStorage(const RInstructionStorage& other) {
+ memcpy(addr(), other.addr(), Size);
+ }
+ void operator=(const RInstructionStorage& other) {
+ memcpy(addr(), other.addr(), Size);
+ }
+};
+
+class RInstruction;
+
+class RecoverReader
+{
+ CompactBufferReader reader_;
+
+ // Number of encoded instructions.
+ uint32_t numInstructions_;
+
+ // Number of instruction read.
+ uint32_t numInstructionsRead_;
+
+ // True if we need to resume after the Resume Point instruction of the
+ // innermost frame.
+ bool resumeAfter_;
+
+ // Space is reserved as part of the RecoverReader to avoid allocations of
+ // data which is needed to decode the current instruction.
+ RInstructionStorage rawData_;
+
+ private:
+ void readRecoverHeader();
+ void readInstruction();
+
+ public:
+ RecoverReader(SnapshotReader& snapshot, const uint8_t* recovers, uint32_t size);
+
+ uint32_t numInstructions() const {
+ return numInstructions_;
+ }
+ uint32_t numInstructionsRead() const {
+ return numInstructionsRead_;
+ }
+
+ bool moreInstructions() const {
+ return numInstructionsRead_ < numInstructions_;
+ }
+ void nextInstruction() {
+ readInstruction();
+ }
+
+ const RInstruction* instruction() const {
+ return reinterpret_cast<const RInstruction*>(rawData_.addr());
+ }
+
+ bool resumeAfter() const {
+ return resumeAfter_;
+ }
+};
+
+} // namespace jit
+} // namespace js
+
+#endif /* jit_Snapshot_h */