The Tor Browser: js/src/jit/Snapshots.h@6474c204b198 (annotated)

js/src/jit/Snapshots.h@6474c204b198 (annotated)

js/src/jit/Snapshots.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- 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 {
 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,
         FLOAT32_REG         = 0x04,
         FLOAT32_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
         // The JSValueType is packed in the Mode.
         TYPED_REG_MIN       = 0x10,
         TYPED_REG_MAX       = 0x17,
         TYPED_REG = TYPED_REG_MIN,
         // The JSValueType is packed in the Mode.
         TYPED_STACK_MIN     = 0x18,
         TYPED_STACK_MAX     = 0x1f,
         TYPED_STACK = TYPED_STACK_MIN,
         INVALID = 0x100,
     };
     // 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.
     union Payload {
         uint32_t index;
         int32_t stackOffset;
         Register gpr;
         FloatRegister 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;
         p.fpu = reg;
         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(FILE *fp, 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)
     {
     }
     RValueAllocation(Mode mode)
       : mode_(mode)
     {
     }
   public:
     RValueAllocation()
       : mode_(INVALID)
     { }
     // DOUBLE_REG
     static RValueAllocation Double(const FloatRegister &reg) {
         return RValueAllocation(DOUBLE_REG, payloadOfFloatRegister(reg));
     }
     // FLOAT32_REG or FLOAT32_STACK
     static RValueAllocation Float32(const FloatRegister &reg) {
         return RValueAllocation(FLOAT32_REG, payloadOfFloatRegister(reg));
     }
     static RValueAllocation Float32(int32_t offset) {
         return RValueAllocation(FLOAT32_STACK, payloadOfStackOffset(offset));
     }
     // TYPED_REG or TYPED_STACK
     static RValueAllocation Typed(JSValueType type, const Register &reg) {
         JS_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) {
         JS_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(const Register &type, const Register &payload) {
         return RValueAllocation(UNTYPED_REG_REG,
                                 payloadOfRegister(type),
                                 payloadOfRegister(payload));
     }
     static RValueAllocation Untyped(const Register &type, int32_t payloadStackOffset) {
         return RValueAllocation(UNTYPED_REG_STACK,
                                 payloadOfRegister(type),
                                 payloadOfStackOffset(payloadStackOffset));
     }
     static RValueAllocation Untyped(int32_t typeStackOffset, const 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(const 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));
     }
     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_;
     }
     uint32_t index() const {
         JS_ASSERT(layoutFromMode(mode()).type1 == PAYLOAD_INDEX);
         return arg1_.index;
     }
     int32_t stackOffset() const {
         JS_ASSERT(layoutFromMode(mode()).type1 == PAYLOAD_STACK_OFFSET);
         return arg1_.stackOffset;
     }
     Register reg() const {
         JS_ASSERT(layoutFromMode(mode()).type1 == PAYLOAD_GPR);
         return arg1_.gpr;
     }
     FloatRegister fpuReg() const {
         JS_ASSERT(layoutFromMode(mode()).type1 == PAYLOAD_FPU);
         return arg1_.fpu;
     }
     JSValueType knownType() const {
         JS_ASSERT(layoutFromMode(mode()).type1 == PAYLOAD_PACKED_TAG);
         return arg1_.type;
     }
     int32_t stackOffset2() const {
         JS_ASSERT(layoutFromMode(mode()).type2 == PAYLOAD_STACK_OFFSET);
         return arg2_.stackOffset;
     }
     Register reg2() const {
         JS_ASSERT(layoutFromMode(mode()).type2 == PAYLOAD_GPR);
         return arg2_.gpr;
     }
   public:
     void dump(FILE *fp) 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:
     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
     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 MResumePoint;
 class RecoverWriter
 {
     CompactBufferWriter writer_;
     uint32_t nframes_;
     uint32_t framesWritten_;
   public:
     SnapshotOffset startRecover(uint32_t frameCount, bool resumeAfter);
     bool writeFrame(const MResumePoint *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;
     }
 };
 typedef mozilla::AlignedStorage<4 * sizeof(uint32_t)> RInstructionStorage;
 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);
     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_;
     }
 };
 }
 }
 #endif /* jit_Snapshot_h */

The Tor Browser / annotate

js/src/jit/Snapshots.h@6474c204b198 (annotated)

js/src/jit/Snapshots.h