michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "jsprf.h"
michael@0: #include "jit/arm/Simulator-arm.h"
michael@0: #include "jit/BaselineIC.h"
michael@0: #include "jit/BaselineJIT.h"
michael@0: #include "jit/CompileInfo.h"
michael@0: #include "jit/IonSpewer.h"
michael@0: #include "jit/Recover.h"
michael@0: #include "jit/RematerializedFrame.h"
michael@0: 
michael@0: #include "vm/ArgumentsObject.h"
michael@0: #include "vm/Debugger.h"
michael@0: #include "vm/TraceLogging.h"
michael@0: 
michael@0: #include "jsscriptinlines.h"
michael@0: 
michael@0: #include "jit/IonFrames-inl.h"
michael@0: 
michael@0: using namespace js;
michael@0: using namespace js::jit;
michael@0: 
michael@0: // BaselineStackBuilder may reallocate its buffer if the current one is too
michael@0: // small. To avoid dangling pointers, BufferPointer represents a pointer into
michael@0: // this buffer as a pointer to the header and a fixed offset.
michael@0: template <typename T>
michael@0: class BufferPointer
michael@0: {
michael@0:     BaselineBailoutInfo **header_;
michael@0:     size_t offset_;
michael@0:     bool heap_;
michael@0: 
michael@0:   public:
michael@0:     BufferPointer(BaselineBailoutInfo **header, size_t offset, bool heap)
michael@0:       : header_(header), offset_(offset), heap_(heap)
michael@0:     { }
michael@0: 
michael@0:     T *get() const {
michael@0:         BaselineBailoutInfo *header = *header_;
michael@0:         if (!heap_)
michael@0:             return (T*)(header->incomingStack + offset_);
michael@0: 
michael@0:         uint8_t *p = header->copyStackTop - offset_;
michael@0:         JS_ASSERT(p >= header->copyStackBottom && p < header->copyStackTop);
michael@0:         return (T*)p;
michael@0:     }
michael@0: 
michael@0:     T &operator*() const { return *get(); }
michael@0:     T *operator->() const { return get(); }
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * BaselineStackBuilder helps abstract the process of rebuilding the C stack on the heap.
michael@0:  * It takes a bailout iterator and keeps track of the point on the C stack from which
michael@0:  * the reconstructed frames will be written.
michael@0:  *
michael@0:  * It exposes methods to write data into the heap memory storing the reconstructed
michael@0:  * stack.  It also exposes method to easily calculate addresses.  This includes both the
michael@0:  * virtual address that a particular value will be at when it's eventually copied onto
michael@0:  * the stack, as well as the current actual address of that value (whether on the heap
michael@0:  * allocated portion being constructed or the existing stack).
michael@0:  *
michael@0:  * The abstraction handles transparent re-allocation of the heap memory when it
michael@0:  * needs to be enlarged to accomodate new data.  Similarly to the C stack, the
michael@0:  * data that's written to the reconstructed stack grows from high to low in memory.
michael@0:  *
michael@0:  * The lowest region of the allocated memory contains a BaselineBailoutInfo structure that
michael@0:  * points to the start and end of the written data.
michael@0:  */
michael@0: struct BaselineStackBuilder
michael@0: {
michael@0:     IonBailoutIterator &iter_;
michael@0:     IonJSFrameLayout *frame_;
michael@0: 
michael@0:     static size_t HeaderSize() {
michael@0:         return AlignBytes(sizeof(BaselineBailoutInfo), sizeof(void *));
michael@0:     };
michael@0:     size_t bufferTotal_;
michael@0:     size_t bufferAvail_;
michael@0:     size_t bufferUsed_;
michael@0:     uint8_t *buffer_;
michael@0:     BaselineBailoutInfo *header_;
michael@0: 
michael@0:     size_t framePushed_;
michael@0: 
michael@0:     BaselineStackBuilder(IonBailoutIterator &iter, size_t initialSize)
michael@0:       : iter_(iter),
michael@0:         frame_(static_cast<IonJSFrameLayout*>(iter.current())),
michael@0:         bufferTotal_(initialSize),
michael@0:         bufferAvail_(0),
michael@0:         bufferUsed_(0),
michael@0:         buffer_(nullptr),
michael@0:         header_(nullptr),
michael@0:         framePushed_(0)
michael@0:     {
michael@0:         JS_ASSERT(bufferTotal_ >= HeaderSize());
michael@0:     }
michael@0: 
michael@0:     ~BaselineStackBuilder() {
michael@0:         js_free(buffer_);
michael@0:     }
michael@0: 
michael@0:     bool init() {
michael@0:         JS_ASSERT(!buffer_);
michael@0:         JS_ASSERT(bufferUsed_ == 0);
michael@0:         buffer_ = reinterpret_cast<uint8_t *>(js_calloc(bufferTotal_));
michael@0:         if (!buffer_)
michael@0:             return false;
michael@0:         bufferAvail_ = bufferTotal_ - HeaderSize();
michael@0:         bufferUsed_ = 0;
michael@0: 
michael@0:         header_ = reinterpret_cast<BaselineBailoutInfo *>(buffer_);
michael@0:         header_->incomingStack = reinterpret_cast<uint8_t *>(frame_);
michael@0:         header_->copyStackTop = buffer_ + bufferTotal_;
michael@0:         header_->copyStackBottom = header_->copyStackTop;
michael@0:         header_->setR0 = 0;
michael@0:         header_->valueR0 = UndefinedValue();
michael@0:         header_->setR1 = 0;
michael@0:         header_->valueR1 = UndefinedValue();
michael@0:         header_->resumeFramePtr = nullptr;
michael@0:         header_->resumeAddr = nullptr;
michael@0:         header_->monitorStub = nullptr;
michael@0:         header_->numFrames = 0;
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     bool enlarge() {
michael@0:         JS_ASSERT(buffer_ != nullptr);
michael@0:         if (bufferTotal_ & mozilla::tl::MulOverflowMask<2>::value)
michael@0:             return false;
michael@0:         size_t newSize = bufferTotal_ * 2;
michael@0:         uint8_t *newBuffer = reinterpret_cast<uint8_t *>(js_calloc(newSize));
michael@0:         if (!newBuffer)
michael@0:             return false;
michael@0:         memcpy((newBuffer + newSize) - bufferUsed_, header_->copyStackBottom, bufferUsed_);
michael@0:         memcpy(newBuffer, header_, sizeof(BaselineBailoutInfo));
michael@0:         js_free(buffer_);
michael@0:         buffer_ = newBuffer;
michael@0:         bufferTotal_ = newSize;
michael@0:         bufferAvail_ = newSize - (HeaderSize() + bufferUsed_);
michael@0: 
michael@0:         header_ = reinterpret_cast<BaselineBailoutInfo *>(buffer_);
michael@0:         header_->copyStackTop = buffer_ + bufferTotal_;
michael@0:         header_->copyStackBottom = header_->copyStackTop - bufferUsed_;
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     BaselineBailoutInfo *info() {
michael@0:         JS_ASSERT(header_ == reinterpret_cast<BaselineBailoutInfo *>(buffer_));
michael@0:         return header_;
michael@0:     }
michael@0: 
michael@0:     BaselineBailoutInfo *takeBuffer() {
michael@0:         JS_ASSERT(header_ == reinterpret_cast<BaselineBailoutInfo *>(buffer_));
michael@0:         buffer_ = nullptr;
michael@0:         return header_;
michael@0:     }
michael@0: 
michael@0:     void resetFramePushed() {
michael@0:         framePushed_ = 0;
michael@0:     }
michael@0: 
michael@0:     size_t framePushed() const {
michael@0:         return framePushed_;
michael@0:     }
michael@0: 
michael@0:     bool subtract(size_t size, const char *info = nullptr) {
michael@0:         // enlarge the buffer if need be.
michael@0:         while (size > bufferAvail_) {
michael@0:             if (!enlarge())
michael@0:                 return false;
michael@0:         }
michael@0: 
michael@0:         // write out element.
michael@0:         header_->copyStackBottom -= size;
michael@0:         bufferAvail_ -= size;
michael@0:         bufferUsed_ += size;
michael@0:         framePushed_ += size;
michael@0:         if (info) {
michael@0:             IonSpew(IonSpew_BaselineBailouts,
michael@0:                     "      SUB_%03d   %p/%p %-15s",
michael@0:                     (int) size, header_->copyStackBottom, virtualPointerAtStackOffset(0), info);
michael@0:         }
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     template <typename T>
michael@0:     bool write(const T &t) {
michael@0:         if (!subtract(sizeof(T)))
michael@0:             return false;
michael@0:         memcpy(header_->copyStackBottom, &t, sizeof(T));
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     template <typename T>
michael@0:     bool writePtr(T *t, const char *info) {
michael@0:         if (!write<T *>(t))
michael@0:             return false;
michael@0:         if (info)
michael@0:             IonSpew(IonSpew_BaselineBailouts,
michael@0:                     "      WRITE_PTR %p/%p %-15s %p",
michael@0:                     header_->copyStackBottom, virtualPointerAtStackOffset(0), info, t);
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     bool writeWord(size_t w, const char *info) {
michael@0:         if (!write<size_t>(w))
michael@0:             return false;
michael@0:         if (info) {
michael@0:             if (sizeof(size_t) == 4) {
michael@0:                 IonSpew(IonSpew_BaselineBailouts,
michael@0:                         "      WRITE_WRD %p/%p %-15s %08x",
michael@0:                         header_->copyStackBottom, virtualPointerAtStackOffset(0), info, w);
michael@0:             } else {
michael@0:                 IonSpew(IonSpew_BaselineBailouts,
michael@0:                         "      WRITE_WRD %p/%p %-15s %016llx",
michael@0:                         header_->copyStackBottom, virtualPointerAtStackOffset(0), info, w);
michael@0:             }
michael@0:         }
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     bool writeValue(Value val, const char *info) {
michael@0:         if (!write<Value>(val))
michael@0:             return false;
michael@0:         if (info) {
michael@0:             IonSpew(IonSpew_BaselineBailouts,
michael@0:                     "      WRITE_VAL %p/%p %-15s %016llx",
michael@0:                     header_->copyStackBottom, virtualPointerAtStackOffset(0), info,
michael@0:                     *((uint64_t *) &val));
michael@0:         }
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     Value popValue() {
michael@0:         JS_ASSERT(bufferUsed_ >= sizeof(Value));
michael@0:         JS_ASSERT(framePushed_ >= sizeof(Value));
michael@0:         bufferAvail_ += sizeof(Value);
michael@0:         bufferUsed_ -= sizeof(Value);
michael@0:         framePushed_ -= sizeof(Value);
michael@0:         Value result = *((Value *) header_->copyStackBottom);
michael@0:         header_->copyStackBottom += sizeof(Value);
michael@0:         return result;
michael@0:     }
michael@0: 
michael@0:     void popValueInto(PCMappingSlotInfo::SlotLocation loc) {
michael@0:         JS_ASSERT(PCMappingSlotInfo::ValidSlotLocation(loc));
michael@0:         switch(loc) {
michael@0:           case PCMappingSlotInfo::SlotInR0:
michael@0:             header_->setR0 = 1;
michael@0:             header_->valueR0 = popValue();
michael@0:             break;
michael@0:           case PCMappingSlotInfo::SlotInR1:
michael@0:             header_->setR1 = 1;
michael@0:             header_->valueR1 = popValue();
michael@0:             break;
michael@0:           default:
michael@0:             JS_ASSERT(loc == PCMappingSlotInfo::SlotIgnore);
michael@0:             popValue();
michael@0:             break;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     void setResumeFramePtr(void *resumeFramePtr) {
michael@0:         header_->resumeFramePtr = resumeFramePtr;
michael@0:     }
michael@0: 
michael@0:     void setResumeAddr(void *resumeAddr) {
michael@0:         header_->resumeAddr = resumeAddr;
michael@0:     }
michael@0: 
michael@0:     void setMonitorStub(ICStub *stub) {
michael@0:         header_->monitorStub = stub;
michael@0:     }
michael@0: 
michael@0:     template <typename T>
michael@0:     BufferPointer<T> pointerAtStackOffset(size_t offset) {
michael@0:         if (offset < bufferUsed_) {
michael@0:             // Calculate offset from copyStackTop.
michael@0:             offset = header_->copyStackTop - (header_->copyStackBottom + offset);
michael@0:             return BufferPointer<T>(&header_, offset, /* heap = */ true);
michael@0:         }
michael@0: 
michael@0:         return BufferPointer<T>(&header_, offset - bufferUsed_, /* heap = */ false);
michael@0:     }
michael@0: 
michael@0:     BufferPointer<Value> valuePointerAtStackOffset(size_t offset) {
michael@0:         return pointerAtStackOffset<Value>(offset);
michael@0:     }
michael@0: 
michael@0:     inline uint8_t *virtualPointerAtStackOffset(size_t offset) {
michael@0:         if (offset < bufferUsed_)
michael@0:             return reinterpret_cast<uint8_t *>(frame_) - (bufferUsed_ - offset);
michael@0:         return reinterpret_cast<uint8_t *>(frame_) + (offset - bufferUsed_);
michael@0:     }
michael@0: 
michael@0:     inline IonJSFrameLayout *startFrame() {
michael@0:         return frame_;
michael@0:     }
michael@0: 
michael@0:     BufferPointer<IonJSFrameLayout> topFrameAddress() {
michael@0:         return pointerAtStackOffset<IonJSFrameLayout>(0);
michael@0:     }
michael@0: 
michael@0:     //
michael@0:     // This method should only be called when the builder is in a state where it is
michael@0:     // starting to construct the stack frame for the next callee.  This means that
michael@0:     // the lowest value on the constructed stack is the return address for the previous
michael@0:     // caller frame.
michael@0:     //
michael@0:     // This method is used to compute the value of the frame pointer (e.g. ebp on x86)
michael@0:     // that would have been saved by the baseline jitcode when it was entered.  In some
michael@0:     // cases, this value can be bogus since we can ensure that the caller would have saved
michael@0:     // it anyway.
michael@0:     //
michael@0:     void *calculatePrevFramePtr() {
michael@0:         // Get the incoming frame.
michael@0:         BufferPointer<IonJSFrameLayout> topFrame = topFrameAddress();
michael@0:         FrameType type = topFrame->prevType();
michael@0: 
michael@0:         // For IonJS and Entry frames, the "saved" frame pointer in the baseline
michael@0:         // frame is meaningless, since Ion saves all registers before calling other ion
michael@0:         // frames, and the entry frame saves all registers too.
michael@0:         if (type == JitFrame_IonJS || type == JitFrame_Entry)
michael@0:             return nullptr;
michael@0: 
michael@0:         // BaselineStub - Baseline calling into Ion.
michael@0:         //  PrevFramePtr needs to point to the BaselineStubFrame's saved frame pointer.
michael@0:         //      STACK_START_ADDR + IonJSFrameLayout::Size() + PREV_FRAME_SIZE
michael@0:         //                      - IonBaselineStubFrameLayout::reverseOffsetOfSavedFramePtr()
michael@0:         if (type == JitFrame_BaselineStub) {
michael@0:             size_t offset = IonJSFrameLayout::Size() + topFrame->prevFrameLocalSize() +
michael@0:                             IonBaselineStubFrameLayout::reverseOffsetOfSavedFramePtr();
michael@0:             return virtualPointerAtStackOffset(offset);
michael@0:         }
michael@0: 
michael@0:         JS_ASSERT(type == JitFrame_Rectifier);
michael@0:         // Rectifier - behaviour depends on the frame preceding the rectifier frame, and
michael@0:         // whether the arch is x86 or not.  The x86 rectifier frame saves the frame pointer,
michael@0:         // so we can calculate it directly.  For other archs, the previous frame pointer
michael@0:         // is stored on the stack in the frame that precedes the rectifier frame.
michael@0:         size_t priorOffset = IonJSFrameLayout::Size() + topFrame->prevFrameLocalSize();
michael@0: #if defined(JS_CODEGEN_X86)
michael@0:         // On X86, the FramePointer is pushed as the first value in the Rectifier frame.
michael@0:         JS_ASSERT(BaselineFrameReg == FramePointer);
michael@0:         priorOffset -= sizeof(void *);
michael@0:         return virtualPointerAtStackOffset(priorOffset);
michael@0: #elif defined(JS_CODEGEN_X64) || defined(JS_CODEGEN_ARM) || defined(JS_CODEGEN_MIPS)
michael@0:         // On X64, ARM and MIPS, the frame pointer save location depends on
michael@0:         // the caller of the rectifier frame.
michael@0:         BufferPointer<IonRectifierFrameLayout> priorFrame =
michael@0:             pointerAtStackOffset<IonRectifierFrameLayout>(priorOffset);
michael@0:         FrameType priorType = priorFrame->prevType();
michael@0:         JS_ASSERT(priorType == JitFrame_IonJS || priorType == JitFrame_BaselineStub);
michael@0: 
michael@0:         // If the frame preceding the rectifier is an IonJS frame, then once again
michael@0:         // the frame pointer does not matter.
michael@0:         if (priorType == JitFrame_IonJS)
michael@0:             return nullptr;
michael@0: 
michael@0:         // Otherwise, the frame preceding the rectifier is a BaselineStub frame.
michael@0:         //  let X = STACK_START_ADDR + IonJSFrameLayout::Size() + PREV_FRAME_SIZE
michael@0:         //      X + IonRectifierFrameLayout::Size()
michael@0:         //        + ((IonRectifierFrameLayout *) X)->prevFrameLocalSize()
michael@0:         //        - BaselineStubFrameLayout::reverseOffsetOfSavedFramePtr()
michael@0:         size_t extraOffset = IonRectifierFrameLayout::Size() + priorFrame->prevFrameLocalSize() +
michael@0:                              IonBaselineStubFrameLayout::reverseOffsetOfSavedFramePtr();
michael@0:         return virtualPointerAtStackOffset(priorOffset + extraOffset);
michael@0: #else
michael@0: #  error "Bad architecture!"
michael@0: #endif
michael@0:     }
michael@0: };
michael@0: 
michael@0: static inline bool
michael@0: IsInlinableFallback(ICFallbackStub *icEntry)
michael@0: {
michael@0:     return icEntry->isCall_Fallback() || icEntry->isGetProp_Fallback() ||
michael@0:            icEntry->isSetProp_Fallback();
michael@0: }
michael@0: 
michael@0: static inline void*
michael@0: GetStubReturnAddress(JSContext *cx, jsbytecode *pc)
michael@0: {
michael@0:     if (IsGetPropPC(pc))
michael@0:         return cx->compartment()->jitCompartment()->baselineGetPropReturnFromIonAddr();
michael@0:     if (IsSetPropPC(pc))
michael@0:         return cx->compartment()->jitCompartment()->baselineSetPropReturnFromIonAddr();
michael@0:     // This should be a call op of some kind, now.
michael@0:     JS_ASSERT(IsCallPC(pc));
michael@0:     return cx->compartment()->jitCompartment()->baselineCallReturnFromIonAddr();
michael@0: }
michael@0: 
michael@0: static inline jsbytecode *
michael@0: GetNextNonLoopEntryPc(jsbytecode *pc)
michael@0: {
michael@0:     JSOp op = JSOp(*pc);
michael@0:     if (op == JSOP_GOTO)
michael@0:         return pc + GET_JUMP_OFFSET(pc);
michael@0:     if (op == JSOP_LOOPENTRY || op == JSOP_NOP || op == JSOP_LOOPHEAD)
michael@0:         return GetNextPc(pc);
michael@0:     return pc;
michael@0: }
michael@0: 
michael@0: // For every inline frame, we write out the following data:
michael@0: //
michael@0: //                      |      ...      |
michael@0: //                      +---------------+
michael@0: //                      |  Descr(???)   |  --- Descr size here is (PREV_FRAME_SIZE)
michael@0: //                      +---------------+
michael@0: //                      |  ReturnAddr   |
michael@0: //             --       +===============+  --- OVERWRITE STARTS HERE  (START_STACK_ADDR)
michael@0: //             |        | PrevFramePtr  |
michael@0: //             |    +-> +---------------+
michael@0: //             |    |   |   Baseline    |
michael@0: //             |    |   |    Frame      |
michael@0: //             |    |   +---------------+
michael@0: //             |    |   |    Fixed0     |
michael@0: //             |    |   +---------------+
michael@0: //         +--<     |   |     ...       |
michael@0: //         |   |    |   +---------------+
michael@0: //         |   |    |   |    FixedF     |
michael@0: //         |   |    |   +---------------+
michael@0: //         |   |    |   |    Stack0     |
michael@0: //         |   |    |   +---------------+
michael@0: //         |   |    |   |     ...       |
michael@0: //         |   |    |   +---------------+
michael@0: //         |   |    |   |    StackS     |
michael@0: //         |   --   |   +---------------+  --- IF NOT LAST INLINE FRAME,
michael@0: //         +------------|  Descr(BLJS)  |  --- CALLING INFO STARTS HERE
michael@0: //                  |   +---------------+
michael@0: //                  |   |  ReturnAddr   | <-- return into main jitcode after IC
michael@0: //             --   |   +===============+
michael@0: //             |    |   |    StubPtr    |
michael@0: //             |    |   +---------------+
michael@0: //             |    +---|   FramePtr    |
michael@0: //             |        +---------------+
michael@0: //             |        |     ArgA      |
michael@0: //             |        +---------------+
michael@0: //             |        |     ...       |
michael@0: //         +--<         +---------------+
michael@0: //         |   |        |     Arg0      |
michael@0: //         |   |        +---------------+
michael@0: //         |   |        |     ThisV     |
michael@0: //         |   --       +---------------+
michael@0: //         |            |  ActualArgC   |
michael@0: //         |            +---------------+
michael@0: //         |            |  CalleeToken  |
michael@0: //         |            +---------------+
michael@0: //         +------------| Descr(BLStub) |
michael@0: //                      +---------------+
michael@0: //                      |  ReturnAddr   | <-- return into ICCall_Scripted IC
michael@0: //             --       +===============+ --- IF CALLEE FORMAL ARGS > ActualArgC
michael@0: //             |        |  UndefinedU   |
michael@0: //             |        +---------------+
michael@0: //             |        |     ...       |
michael@0: //             |        +---------------+
michael@0: //             |        |  Undefined0   |
michael@0: //             |        +---------------+
michael@0: //         +--<         |     ArgA      |
michael@0: //         |   |        +---------------+
michael@0: //         |   |        |     ...       |
michael@0: //         |   |        +---------------+
michael@0: //         |   |        |     Arg0      |
michael@0: //         |   |        +---------------+
michael@0: //         |   |        |     ThisV     |
michael@0: //         |   --       +---------------+
michael@0: //         |            |  ActualArgC   |
michael@0: //         |            +---------------+
michael@0: //         |            |  CalleeToken  |
michael@0: //         |            +---------------+
michael@0: //         +------------|  Descr(Rect)  |
michael@0: //                      +---------------+
michael@0: //                      |  ReturnAddr   | <-- return into ArgumentsRectifier after call
michael@0: //                      +===============+
michael@0: //
michael@0: static bool
michael@0: InitFromBailout(JSContext *cx, HandleScript caller, jsbytecode *callerPC,
michael@0:                 HandleFunction fun, HandleScript script, IonScript *ionScript,
michael@0:                 SnapshotIterator &iter, bool invalidate, BaselineStackBuilder &builder,
michael@0:                 AutoValueVector &startFrameFormals, MutableHandleFunction nextCallee,
michael@0:                 jsbytecode **callPC, const ExceptionBailoutInfo *excInfo)
michael@0: {
michael@0:     MOZ_ASSERT(script->hasBaselineScript());
michael@0: 
michael@0:     // Are we catching an exception?
michael@0:     bool catchingException = excInfo && excInfo->catchingException();
michael@0: 
michael@0:     // If we are catching an exception, we are bailing out to a catch or
michael@0:     // finally block and this is the frame where we will resume. Usually the
michael@0:     // expression stack should be empty in this case but there can be
michael@0:     // iterators on the stack.
michael@0:     uint32_t exprStackSlots;
michael@0:     if (catchingException)
michael@0:         exprStackSlots = excInfo->numExprSlots();
michael@0:     else
michael@0:         exprStackSlots = iter.numAllocations() - (script->nfixed() + CountArgSlots(script, fun));
michael@0: 
michael@0:     builder.resetFramePushed();
michael@0: 
michael@0:     // Build first baseline frame:
michael@0:     // +===============+
michael@0:     // | PrevFramePtr  |
michael@0:     // +---------------+
michael@0:     // |   Baseline    |
michael@0:     // |    Frame      |
michael@0:     // +---------------+
michael@0:     // |    Fixed0     |
michael@0:     // +---------------+
michael@0:     // |     ...       |
michael@0:     // +---------------+
michael@0:     // |    FixedF     |
michael@0:     // +---------------+
michael@0:     // |    Stack0     |
michael@0:     // +---------------+
michael@0:     // |     ...       |
michael@0:     // +---------------+
michael@0:     // |    StackS     |
michael@0:     // +---------------+  --- IF NOT LAST INLINE FRAME,
michael@0:     // |  Descr(BLJS)  |  --- CALLING INFO STARTS HERE
michael@0:     // +---------------+
michael@0:     // |  ReturnAddr   | <-- return into main jitcode after IC
michael@0:     // +===============+
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      Unpacking %s:%d", script->filename(), script->lineno());
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      [BASELINE-JS FRAME]");
michael@0: 
michael@0:     // Calculate and write the previous frame pointer value.
michael@0:     // Record the virtual stack offset at this location.  Later on, if we end up
michael@0:     // writing out a BaselineStub frame for the next callee, we'll need to save the
michael@0:     // address.
michael@0:     void *prevFramePtr = builder.calculatePrevFramePtr();
michael@0:     if (!builder.writePtr(prevFramePtr, "PrevFramePtr"))
michael@0:         return false;
michael@0:     prevFramePtr = builder.virtualPointerAtStackOffset(0);
michael@0: 
michael@0:     // Write struct BaselineFrame.
michael@0:     if (!builder.subtract(BaselineFrame::Size(), "BaselineFrame"))
michael@0:         return false;
michael@0:     BufferPointer<BaselineFrame> blFrame = builder.pointerAtStackOffset<BaselineFrame>(0);
michael@0: 
michael@0:     // Initialize BaselineFrame::frameSize
michael@0:     uint32_t frameSize = BaselineFrame::Size() + BaselineFrame::FramePointerOffset +
michael@0:                          (sizeof(Value) * (script->nfixed() + exprStackSlots));
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      FrameSize=%d", (int) frameSize);
michael@0:     blFrame->setFrameSize(frameSize);
michael@0: 
michael@0:     uint32_t flags = 0;
michael@0: 
michael@0:     // If SPS Profiler is enabled, mark the frame as having pushed an SPS entry.
michael@0:     // This may be wrong for the last frame of ArgumentCheck bailout, but
michael@0:     // that will be fixed later.
michael@0:     if (ionScript->hasSPSInstrumentation()) {
michael@0:         if (callerPC == nullptr) {
michael@0:             IonSpew(IonSpew_BaselineBailouts, "      Setting SPS flag on top frame!");
michael@0:             flags |= BaselineFrame::HAS_PUSHED_SPS_FRAME;
michael@0:         } else if (js_JitOptions.profileInlineFrames) {
michael@0:             IonSpew(IonSpew_BaselineBailouts, "      Setting SPS flag on inline frame!");
michael@0:             flags |= BaselineFrame::HAS_PUSHED_SPS_FRAME;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // Initialize BaselineFrame's scopeChain and argsObj
michael@0:     JSObject *scopeChain = nullptr;
michael@0:     Value returnValue;
michael@0:     ArgumentsObject *argsObj = nullptr;
michael@0:     BailoutKind bailoutKind = iter.bailoutKind();
michael@0:     if (bailoutKind == Bailout_ArgumentCheck) {
michael@0:         // Temporary hack -- skip the (unused) scopeChain, because it could be
michael@0:         // bogus (we can fail before the scope chain slot is set). Strip the
michael@0:         // hasScopeChain flag and this will be fixed up later in |FinishBailoutToBaseline|,
michael@0:         // which calls |EnsureHasScopeObjects|.
michael@0:         IonSpew(IonSpew_BaselineBailouts, "      Bailout_ArgumentCheck! (no valid scopeChain)");
michael@0:         iter.skip();
michael@0: 
michael@0:         // skip |return value|
michael@0:         iter.skip();
michael@0:         returnValue = UndefinedValue();
michael@0: 
michael@0:         // Scripts with |argumentsHasVarBinding| have an extra slot.
michael@0:         if (script->argumentsHasVarBinding()) {
michael@0:             IonSpew(IonSpew_BaselineBailouts,
michael@0:                     "      Bailout_ArgumentCheck for script with argumentsHasVarBinding!"
michael@0:                     "Using empty arguments object");
michael@0:             iter.skip();
michael@0:         }
michael@0:     } else {
michael@0:         Value v = iter.read();
michael@0:         if (v.isObject()) {
michael@0:             scopeChain = &v.toObject();
michael@0:             if (fun && fun->isHeavyweight())
michael@0:                 flags |= BaselineFrame::HAS_CALL_OBJ;
michael@0:         } else {
michael@0:             JS_ASSERT(v.isUndefined() || v.isMagic(JS_OPTIMIZED_OUT));
michael@0: 
michael@0:             // Get scope chain from function or script.
michael@0:             if (fun) {
michael@0:                 // If pcOffset == 0, we may have to push a new call object, so
michael@0:                 // we leave scopeChain nullptr and enter baseline code before
michael@0:                 // the prologue.
michael@0:                 if (iter.pcOffset() != 0 || iter.resumeAfter())
michael@0:                     scopeChain = fun->environment();
michael@0:             } else {
michael@0:                 // For global, compile-and-go scripts the scope chain is the
michael@0:                 // script's global (Ion does not compile non-compile-and-go
michael@0:                 // scripts). Also note that it's invalid to resume into the
michael@0:                 // prologue in this case because the prologue expects the scope
michael@0:                 // chain in R1 for eval and global scripts.
michael@0:                 JS_ASSERT(!script->isForEval());
michael@0:                 JS_ASSERT(script->compileAndGo());
michael@0:                 scopeChain = &(script->global());
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         // Make sure to add HAS_RVAL to flags here because setFlags() below
michael@0:         // will clobber it.
michael@0:         returnValue = iter.read();
michael@0:         flags |= BaselineFrame::HAS_RVAL;
michael@0: 
michael@0:         // If script maybe has an arguments object, the third slot will hold it.
michael@0:         if (script->argumentsHasVarBinding()) {
michael@0:             v = iter.read();
michael@0:             JS_ASSERT(v.isObject() || v.isUndefined() || v.isMagic(JS_OPTIMIZED_OUT));
michael@0:             if (v.isObject())
michael@0:                 argsObj = &v.toObject().as<ArgumentsObject>();
michael@0:         }
michael@0:     }
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      ScopeChain=%p", scopeChain);
michael@0:     blFrame->setScopeChain(scopeChain);
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      ReturnValue=%016llx", *((uint64_t *) &returnValue));
michael@0:     blFrame->setReturnValue(returnValue);
michael@0: 
michael@0:     // Do not need to initialize scratchValue field in BaselineFrame.
michael@0:     blFrame->setFlags(flags);
michael@0: 
michael@0:     // initArgsObjUnchecked modifies the frame's flags, so call it after setFlags.
michael@0:     if (argsObj)
michael@0:         blFrame->initArgsObjUnchecked(*argsObj);
michael@0: 
michael@0:     if (fun) {
michael@0:         // The unpacked thisv and arguments should overwrite the pushed args present
michael@0:         // in the calling frame.
michael@0:         Value thisv = iter.read();
michael@0:         IonSpew(IonSpew_BaselineBailouts, "      Is function!");
michael@0:         IonSpew(IonSpew_BaselineBailouts, "      thisv=%016llx", *((uint64_t *) &thisv));
michael@0: 
michael@0:         size_t thisvOffset = builder.framePushed() + IonJSFrameLayout::offsetOfThis();
michael@0:         *builder.valuePointerAtStackOffset(thisvOffset) = thisv;
michael@0: 
michael@0:         JS_ASSERT(iter.numAllocations() >= CountArgSlots(script, fun));
michael@0:         IonSpew(IonSpew_BaselineBailouts, "      frame slots %u, nargs %u, nfixed %u",
michael@0:                 iter.numAllocations(), fun->nargs(), script->nfixed());
michael@0: 
michael@0:         if (!callerPC) {
michael@0:             // This is the first frame. Store the formals in a Vector until we
michael@0:             // are done. Due to UCE and phi elimination, we could store an
michael@0:             // UndefinedValue() here for formals we think are unused, but
michael@0:             // locals may still reference the original argument slot
michael@0:             // (MParameter/LArgument) and expect the original Value.
michael@0:             JS_ASSERT(startFrameFormals.empty());
michael@0:             if (!startFrameFormals.resize(fun->nargs()))
michael@0:                 return false;
michael@0:         }
michael@0: 
michael@0:         for (uint32_t i = 0; i < fun->nargs(); i++) {
michael@0:             Value arg = iter.read();
michael@0:             IonSpew(IonSpew_BaselineBailouts, "      arg %d = %016llx",
michael@0:                         (int) i, *((uint64_t *) &arg));
michael@0:             if (callerPC) {
michael@0:                 size_t argOffset = builder.framePushed() + IonJSFrameLayout::offsetOfActualArg(i);
michael@0:                 *builder.valuePointerAtStackOffset(argOffset) = arg;
michael@0:             } else {
michael@0:                 startFrameFormals[i] = arg;
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     for (uint32_t i = 0; i < script->nfixed(); i++) {
michael@0:         Value slot = iter.read();
michael@0:         if (!builder.writeValue(slot, "FixedValue"))
michael@0:             return false;
michael@0:     }
michael@0: 
michael@0:     // Get the pc. If we are handling an exception, resume at the pc of the
michael@0:     // catch or finally block.
michael@0:     jsbytecode *pc = catchingException ? excInfo->resumePC() : script->offsetToPC(iter.pcOffset());
michael@0:     bool resumeAfter = catchingException ? false : iter.resumeAfter();
michael@0: 
michael@0:     JSOp op = JSOp(*pc);
michael@0: 
michael@0:     // Fixup inlined JSOP_FUNCALL, JSOP_FUNAPPLY, and accessors on the caller side.
michael@0:     // On the caller side this must represent like the function wasn't inlined.
michael@0:     uint32_t pushedSlots = 0;
michael@0:     AutoValueVector savedCallerArgs(cx);
michael@0:     bool needToSaveArgs = op == JSOP_FUNAPPLY || IsGetPropPC(pc) || IsSetPropPC(pc);
michael@0:     if (iter.moreFrames() && (op == JSOP_FUNCALL || needToSaveArgs))
michael@0:     {
michael@0:         uint32_t inlined_args = 0;
michael@0:         if (op == JSOP_FUNCALL)
michael@0:             inlined_args = 2 + GET_ARGC(pc) - 1;
michael@0:         else if (op == JSOP_FUNAPPLY)
michael@0:             inlined_args = 2 + blFrame->numActualArgs();
michael@0:         else
michael@0:             inlined_args = 2 + IsSetPropPC(pc);
michael@0: 
michael@0:         JS_ASSERT(exprStackSlots >= inlined_args);
michael@0:         pushedSlots = exprStackSlots - inlined_args;
michael@0: 
michael@0:         IonSpew(IonSpew_BaselineBailouts,
michael@0:                 "      pushing %u expression stack slots before fixup",
michael@0:                 pushedSlots);
michael@0:         for (uint32_t i = 0; i < pushedSlots; i++) {
michael@0:             Value v = iter.read();
michael@0:             if (!builder.writeValue(v, "StackValue"))
michael@0:                 return false;
michael@0:         }
michael@0: 
michael@0:         if (op == JSOP_FUNCALL) {
michael@0:             // When funcall got inlined and the native js_fun_call was bypassed,
michael@0:             // the stack state is incorrect. To restore correctly it must look like
michael@0:             // js_fun_call was actually called. This means transforming the stack
michael@0:             // from |target, this, args| to |js_fun_call, target, this, args|
michael@0:             // The js_fun_call is never read, so just pushing undefined now.
michael@0:             IonSpew(IonSpew_BaselineBailouts, "      pushing undefined to fixup funcall");
michael@0:             if (!builder.writeValue(UndefinedValue(), "StackValue"))
michael@0:                 return false;
michael@0:         }
michael@0: 
michael@0:         if (needToSaveArgs) {
michael@0:             // When an accessor is inlined, the whole thing is a lie. There
michael@0:             // should never have been a call there. Fix the caller's stack to
michael@0:             // forget it ever happened.
michael@0: 
michael@0:             // When funapply gets inlined we take all arguments out of the
michael@0:             // arguments array. So the stack state is incorrect. To restore
michael@0:             // correctly it must look like js_fun_apply was actually called.
michael@0:             // This means transforming the stack from |target, this, arg1, ...|
michael@0:             // to |js_fun_apply, target, this, argObject|.
michael@0:             // Since the information is never read, we can just push undefined
michael@0:             // for all values.
michael@0:             if (op == JSOP_FUNAPPLY) {
michael@0:                 IonSpew(IonSpew_BaselineBailouts, "      pushing 4x undefined to fixup funapply");
michael@0:                 if (!builder.writeValue(UndefinedValue(), "StackValue"))
michael@0:                     return false;
michael@0:                 if (!builder.writeValue(UndefinedValue(), "StackValue"))
michael@0:                     return false;
michael@0:                 if (!builder.writeValue(UndefinedValue(), "StackValue"))
michael@0:                     return false;
michael@0:                 if (!builder.writeValue(UndefinedValue(), "StackValue"))
michael@0:                     return false;
michael@0:             }
michael@0:             // Save the actual arguments. They are needed on the callee side
michael@0:             // as the arguments. Else we can't recover them.
michael@0:             if (!savedCallerArgs.resize(inlined_args))
michael@0:                 return false;
michael@0:             for (uint32_t i = 0; i < inlined_args; i++)
michael@0:                 savedCallerArgs[i] = iter.read();
michael@0: 
michael@0:             if (IsSetPropPC(pc)) {
michael@0:                 // We would love to just save all the arguments and leave them
michael@0:                 // in the stub frame pushed below, but we will lose the inital
michael@0:                 // argument which the function was called with, which we must
michael@0:                 // return to the caller, even if the setter internally modifies
michael@0:                 // its arguments. Stash the initial argument on the stack, to be
michael@0:                 // later retrieved by the SetProp_Fallback stub.
michael@0:                 Value initialArg = savedCallerArgs[inlined_args - 1];
michael@0:                 IonSpew(IonSpew_BaselineBailouts, "     pushing setter's initial argument");
michael@0:                 if (!builder.writeValue(initialArg, "StackValue"))
michael@0:                     return false;
michael@0:             }
michael@0:             pushedSlots = exprStackSlots;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      pushing %u expression stack slots",
michael@0:                                       exprStackSlots - pushedSlots);
michael@0:     for (uint32_t i = pushedSlots; i < exprStackSlots; i++) {
michael@0:         Value v;
michael@0: 
michael@0:         if (!iter.moreFrames() && i == exprStackSlots - 1 &&
michael@0:             cx->runtime()->hasIonReturnOverride())
michael@0:         {
michael@0:             // If coming from an invalidation bailout, and this is the topmost
michael@0:             // value, and a value override has been specified, don't read from the
michael@0:             // iterator. Otherwise, we risk using a garbage value.
michael@0:             JS_ASSERT(invalidate);
michael@0:             iter.skip();
michael@0:             IonSpew(IonSpew_BaselineBailouts, "      [Return Override]");
michael@0:             v = cx->runtime()->takeIonReturnOverride();
michael@0:         } else if (excInfo && excInfo->propagatingIonExceptionForDebugMode()) {
michael@0:             // If we are in the middle of propagating an exception from Ion by
michael@0:             // bailing to baseline due to debug mode, we might not have all
michael@0:             // the stack if we are at the newest frame.
michael@0:             //
michael@0:             // For instance, if calling |f()| pushed an Ion frame which threw,
michael@0:             // the snapshot expects the return value to be pushed, but it's
michael@0:             // possible nothing was pushed before we threw. Iterators might
michael@0:             // still be on the stack, so we can't just drop the stack.
michael@0:             MOZ_ASSERT(cx->compartment()->debugMode());
michael@0:             if (iter.moreFrames())
michael@0:                 v = iter.read();
michael@0:             else
michael@0:                 v = MagicValue(JS_OPTIMIZED_OUT);
michael@0:         } else {
michael@0:             v = iter.read();
michael@0:         }
michael@0:         if (!builder.writeValue(v, "StackValue"))
michael@0:             return false;
michael@0:     }
michael@0: 
michael@0:     size_t endOfBaselineJSFrameStack = builder.framePushed();
michael@0: 
michael@0:     // If we are resuming at a LOOPENTRY op, resume at the next op to avoid
michael@0:     // a bailout -> enter Ion -> bailout loop with --ion-eager. See also
michael@0:     // ThunkToInterpreter.
michael@0:     //
michael@0:     // The algorithm below is the "tortoise and the hare" algorithm. See bug
michael@0:     // 994444 for more explanation.
michael@0:     if (!resumeAfter) {
michael@0:         jsbytecode *fasterPc = pc;
michael@0:         while (true) {
michael@0:             pc = GetNextNonLoopEntryPc(pc);
michael@0:             fasterPc = GetNextNonLoopEntryPc(GetNextNonLoopEntryPc(fasterPc));
michael@0:             if (fasterPc == pc)
michael@0:                 break;
michael@0:         }
michael@0:         op = JSOp(*pc);
michael@0:     }
michael@0: 
michael@0:     uint32_t pcOff = script->pcToOffset(pc);
michael@0:     bool isCall = IsCallPC(pc);
michael@0:     BaselineScript *baselineScript = script->baselineScript();
michael@0: 
michael@0: #ifdef DEBUG
michael@0:     uint32_t expectedDepth;
michael@0:     bool reachablePC;
michael@0:     if (!ReconstructStackDepth(cx, script, resumeAfter ? GetNextPc(pc) : pc, &expectedDepth, &reachablePC))
michael@0:         return false;
michael@0: 
michael@0:     if (reachablePC) {
michael@0:         if (op != JSOP_FUNAPPLY || !iter.moreFrames() || resumeAfter) {
michael@0:             if (op == JSOP_FUNCALL) {
michael@0:                 // For fun.call(this, ...); the reconstructStackDepth will
michael@0:                 // include the this. When inlining that is not included.
michael@0:                 // So the exprStackSlots will be one less.
michael@0:                 JS_ASSERT(expectedDepth - exprStackSlots <= 1);
michael@0:             } else if (iter.moreFrames() && (IsGetPropPC(pc) || IsSetPropPC(pc))) {
michael@0:                 // Accessors coming out of ion are inlined via a complete
michael@0:                 // lie perpetrated by the compiler internally. Ion just rearranges
michael@0:                 // the stack, and pretends that it looked like a call all along.
michael@0:                 // This means that the depth is actually one *more* than expected
michael@0:                 // by the interpreter, as there is now a JSFunction, |this| and [arg],
michael@0:                 // rather than the expected |this| and [arg]
michael@0:                 // Note that none of that was pushed, but it's still reflected
michael@0:                 // in exprStackSlots.
michael@0:                 JS_ASSERT(exprStackSlots - expectedDepth == 1);
michael@0:             } else {
michael@0:                 // For fun.apply({}, arguments) the reconstructStackDepth will
michael@0:                 // have stackdepth 4, but it could be that we inlined the
michael@0:                 // funapply. In that case exprStackSlots, will have the real
michael@0:                 // arguments in the slots and not be 4.
michael@0:                 JS_ASSERT(exprStackSlots == expectedDepth);
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      Resuming %s pc offset %d (op %s) (line %d) of %s:%d",
michael@0:                 resumeAfter ? "after" : "at", (int) pcOff, js_CodeName[op],
michael@0:                 PCToLineNumber(script, pc), script->filename(), (int) script->lineno());
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      Bailout kind: %s",
michael@0:             BailoutKindString(bailoutKind));
michael@0: #endif
michael@0: 
michael@0:     // If this was the last inline frame, or we are bailing out to a catch or
michael@0:     // finally block in this frame, then unpacking is almost done.
michael@0:     if (!iter.moreFrames() || catchingException) {
michael@0:         // Last frame, so PC for call to next frame is set to nullptr.
michael@0:         *callPC = nullptr;
michael@0: 
michael@0:         // If the bailout was a resumeAfter, and the opcode is monitored,
michael@0:         // then the bailed out state should be in a position to enter
michael@0:         // into the ICTypeMonitor chain for the op.
michael@0:         bool enterMonitorChain = false;
michael@0:         if (resumeAfter && (js_CodeSpec[op].format & JOF_TYPESET)) {
michael@0:             // Not every monitored op has a monitored fallback stub, e.g.
michael@0:             // JSOP_NEWOBJECT, which always returns the same type for a
michael@0:             // particular script/pc location.
michael@0:             ICEntry &icEntry = baselineScript->icEntryFromPCOffset(pcOff);
michael@0:             ICFallbackStub *fallbackStub = icEntry.firstStub()->getChainFallback();
michael@0:             if (fallbackStub->isMonitoredFallback())
michael@0:                 enterMonitorChain = true;
michael@0:         }
michael@0: 
michael@0:         uint32_t numCallArgs = isCall ? GET_ARGC(pc) : 0;
michael@0: 
michael@0:         if (resumeAfter && !enterMonitorChain)
michael@0:             pc = GetNextPc(pc);
michael@0: 
michael@0:         builder.setResumeFramePtr(prevFramePtr);
michael@0: 
michael@0:         if (enterMonitorChain) {
michael@0:             ICEntry &icEntry = baselineScript->icEntryFromPCOffset(pcOff);
michael@0:             ICFallbackStub *fallbackStub = icEntry.firstStub()->getChainFallback();
michael@0:             JS_ASSERT(fallbackStub->isMonitoredFallback());
michael@0:             IonSpew(IonSpew_BaselineBailouts, "      [TYPE-MONITOR CHAIN]");
michael@0:             ICMonitoredFallbackStub *monFallbackStub = fallbackStub->toMonitoredFallbackStub();
michael@0:             ICStub *firstMonStub = monFallbackStub->fallbackMonitorStub()->firstMonitorStub();
michael@0: 
michael@0:             // To enter a monitoring chain, we load the top stack value into R0
michael@0:             IonSpew(IonSpew_BaselineBailouts, "      Popping top stack value into R0.");
michael@0:             builder.popValueInto(PCMappingSlotInfo::SlotInR0);
michael@0: 
michael@0:             // Need to adjust the frameSize for the frame to match the values popped
michael@0:             // into registers.
michael@0:             frameSize -= sizeof(Value);
michael@0:             blFrame->setFrameSize(frameSize);
michael@0:             IonSpew(IonSpew_BaselineBailouts, "      Adjusted framesize -= %d: %d",
michael@0:                             (int) sizeof(Value), (int) frameSize);
michael@0: 
michael@0:             // If resuming into a JSOP_CALL, baseline keeps the arguments on the
michael@0:             // stack and pops them only after returning from the call IC.
michael@0:             // Push undefs onto the stack in anticipation of the popping of the
michael@0:             // callee, thisv, and actual arguments passed from the caller's frame.
michael@0:             if (isCall) {
michael@0:                 builder.writeValue(UndefinedValue(), "CallOp FillerCallee");
michael@0:                 builder.writeValue(UndefinedValue(), "CallOp FillerThis");
michael@0:                 for (uint32_t i = 0; i < numCallArgs; i++)
michael@0:                     builder.writeValue(UndefinedValue(), "CallOp FillerArg");
michael@0: 
michael@0:                 frameSize += (numCallArgs + 2) * sizeof(Value);
michael@0:                 blFrame->setFrameSize(frameSize);
michael@0:                 IonSpew(IonSpew_BaselineBailouts, "      Adjusted framesize += %d: %d",
michael@0:                                 (int) ((numCallArgs + 2) * sizeof(Value)), (int) frameSize);
michael@0:             }
michael@0: 
michael@0:             // Set the resume address to the return point from the IC, and set
michael@0:             // the monitor stub addr.
michael@0:             builder.setResumeAddr(baselineScript->returnAddressForIC(icEntry));
michael@0:             builder.setMonitorStub(firstMonStub);
michael@0:             IonSpew(IonSpew_BaselineBailouts, "      Set resumeAddr=%p monitorStub=%p",
michael@0:                     baselineScript->returnAddressForIC(icEntry), firstMonStub);
michael@0: 
michael@0:         } else {
michael@0:             // If needed, initialize BaselineBailoutInfo's valueR0 and/or valueR1 with the
michael@0:             // top stack values.
michael@0:             PCMappingSlotInfo slotInfo;
michael@0:             uint8_t *nativeCodeForPC = baselineScript->nativeCodeForPC(script, pc, &slotInfo);
michael@0:             unsigned numUnsynced = slotInfo.numUnsynced();
michael@0:             JS_ASSERT(numUnsynced <= 2);
michael@0:             PCMappingSlotInfo::SlotLocation loc1, loc2;
michael@0:             if (numUnsynced > 0) {
michael@0:                 loc1 = slotInfo.topSlotLocation();
michael@0:                 IonSpew(IonSpew_BaselineBailouts, "      Popping top stack value into %d.",
michael@0:                             (int) loc1);
michael@0:                 builder.popValueInto(loc1);
michael@0:             }
michael@0:             if (numUnsynced > 1) {
michael@0:                 loc2 = slotInfo.nextSlotLocation();
michael@0:                 IonSpew(IonSpew_BaselineBailouts, "      Popping next stack value into %d.",
michael@0:                             (int) loc2);
michael@0:                 JS_ASSERT_IF(loc1 != PCMappingSlotInfo::SlotIgnore, loc1 != loc2);
michael@0:                 builder.popValueInto(loc2);
michael@0:             }
michael@0: 
michael@0:             // Need to adjust the frameSize for the frame to match the values popped
michael@0:             // into registers.
michael@0:             frameSize -= sizeof(Value) * numUnsynced;
michael@0:             blFrame->setFrameSize(frameSize);
michael@0:             IonSpew(IonSpew_BaselineBailouts, "      Adjusted framesize -= %d: %d",
michael@0:                             int(sizeof(Value) * numUnsynced), int(frameSize));
michael@0: 
michael@0:             // If scopeChain is nullptr, then bailout is occurring during argument check.
michael@0:             // In this case, resume into the prologue.
michael@0:             uint8_t *opReturnAddr;
michael@0:             if (scopeChain == nullptr) {
michael@0:                 // Global and eval scripts expect the scope chain in R1, so only
michael@0:                 // resume into the prologue for function scripts.
michael@0:                 JS_ASSERT(fun);
michael@0:                 JS_ASSERT(numUnsynced == 0);
michael@0:                 opReturnAddr = baselineScript->prologueEntryAddr();
michael@0:                 IonSpew(IonSpew_BaselineBailouts, "      Resuming into prologue.");
michael@0: 
michael@0:                 // If bailing into prologue, HAS_PUSHED_SPS_FRAME should not be set on frame.
michael@0:                 blFrame->unsetPushedSPSFrame();
michael@0: 
michael@0:                 if (cx->runtime()->spsProfiler.enabled()) {
michael@0:                     if (js_JitOptions.profileInlineFrames) {
michael@0:                         // If SPS is enabled, there are two corner cases to handle:
michael@0:                         //  1. If resuming into the prologue, and innermost frame is an inlined
michael@0:                         //     frame, and bailout is because of argument check failure, then:
michael@0:                         //          Top SPS profiler entry would be for caller frame.
michael@0:                         //          Ion would not have set the PC index field on that frame
michael@0:                         //              (since this bailout happens before MFunctionBoundary).
michael@0:                         //          Make sure that's done now.
michael@0:                         //  2. If resuming into the prologue, and the bailout is NOT because of an
michael@0:                         //     argument check, then:
michael@0:                         //          Top SPS profiler entry would be for callee frame.
michael@0:                         //          Ion would already have pushed an SPS entry for this frame.
michael@0:                         //          The pc for this entry would be set to nullptr.
michael@0:                         //          Make sure it's set to script->pc.
michael@0:                         if (caller && bailoutKind == Bailout_ArgumentCheck) {
michael@0:                             IonSpew(IonSpew_BaselineBailouts, "      Setting PCidx on innermost "
michael@0:                                     "inlined frame's parent's SPS entry (%s:%d) (pcIdx=%d)!",
michael@0:                                     caller->filename(), caller->lineno(),
michael@0:                                     caller->pcToOffset(callerPC));
michael@0:                             cx->runtime()->spsProfiler.updatePC(caller, callerPC);
michael@0: 
michael@0:                         } else if (bailoutKind != Bailout_ArgumentCheck) {
michael@0:                             IonSpew(IonSpew_BaselineBailouts,
michael@0:                                     "      Popping SPS entry for innermost inlined frame");
michael@0:                             cx->runtime()->spsProfiler.exit(script, fun);
michael@0:                         }
michael@0: 
michael@0:                     } else {
michael@0:                         // If not profiling inline frames, then this is logically simpler.
michael@0:                         //
michael@0:                         // 1. If resuming into inline code, then the top SPS entry will be
michael@0:                         // for the outermost caller, and will have an uninitialized PC.
michael@0:                         // This will be fixed up later in BailoutIonToBaseline.
michael@0:                         //
michael@0:                         // 2. If resuming into top-level code prologue, with ArgumentCheck,
michael@0:                         // no SPS entry will have been pushed.  Can be left alone.
michael@0:                         //
michael@0:                         // 3. If resuming into top-level code prologue, without ArgumentCheck,
michael@0:                         // an SPS entry will have been pushed, and needs to be popped.
michael@0:                         //
michael@0:                         // 4. If resuming into top-level code main body, an SPS entry will
michael@0:                         // have been pushed, and can be left alone.
michael@0:                         //
michael@0:                         // Only need to handle case 3 here.
michael@0:                         if (!caller && bailoutKind != Bailout_ArgumentCheck) {
michael@0:                             IonSpew(IonSpew_BaselineBailouts,
michael@0:                                     "      Popping SPS entry for outermost frame");
michael@0:                             cx->runtime()->spsProfiler.exit(script, fun);
michael@0:                         }
michael@0:                     }
michael@0:                 }
michael@0:             } else {
michael@0:                 opReturnAddr = nativeCodeForPC;
michael@0:             }
michael@0:             builder.setResumeAddr(opReturnAddr);
michael@0:             IonSpew(IonSpew_BaselineBailouts, "      Set resumeAddr=%p", opReturnAddr);
michael@0:         }
michael@0: 
michael@0:         if (cx->runtime()->spsProfiler.enabled()) {
michael@0:             if (blFrame->hasPushedSPSFrame()) {
michael@0:                 // Set PC index to 0 for the innermost frame to match what the
michael@0:                 // interpreter and Baseline do: they update the SPS pc for
michael@0:                 // JSOP_CALL ops but set it to 0 when running other ops. Ion code
michael@0:                 // can set the pc to NullPCIndex and this will confuse SPS when
michael@0:                 // Baseline calls into the VM at non-CALL ops and re-enters JS.
michael@0:                 IonSpew(IonSpew_BaselineBailouts, "      Setting PCidx for last frame to 0");
michael@0:                 cx->runtime()->spsProfiler.updatePC(script, script->code());
michael@0:             }
michael@0: 
michael@0:             // Register bailout with profiler.
michael@0:             const char *filename = script->filename();
michael@0:             if (filename == nullptr)
michael@0:                 filename = "<unknown>";
michael@0:             unsigned len = strlen(filename) + 200;
michael@0:             char *buf = js_pod_malloc<char>(len);
michael@0:             if (buf == nullptr)
michael@0:                 return false;
michael@0:             JS_snprintf(buf, len, "%s %s %s on line %d of %s:%d",
michael@0:                                   BailoutKindString(bailoutKind),
michael@0:                                   resumeAfter ? "after" : "at",
michael@0:                                   js_CodeName[op],
michael@0:                                   int(PCToLineNumber(script, pc)),
michael@0:                                   filename,
michael@0:                                   int(script->lineno()));
michael@0:             cx->runtime()->spsProfiler.markEvent(buf);
michael@0:             js_free(buf);
michael@0:         }
michael@0: 
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     *callPC = pc;
michael@0: 
michael@0:     // Write out descriptor of BaselineJS frame.
michael@0:     size_t baselineFrameDescr = MakeFrameDescriptor((uint32_t) builder.framePushed(),
michael@0:                                                     JitFrame_BaselineJS);
michael@0:     if (!builder.writeWord(baselineFrameDescr, "Descriptor"))
michael@0:         return false;
michael@0: 
michael@0:     // Calculate and write out return address.
michael@0:     // The icEntry in question MUST have an inlinable fallback stub.
michael@0:     ICEntry &icEntry = baselineScript->icEntryFromPCOffset(pcOff);
michael@0:     JS_ASSERT(IsInlinableFallback(icEntry.firstStub()->getChainFallback()));
michael@0:     if (!builder.writePtr(baselineScript->returnAddressForIC(icEntry), "ReturnAddr"))
michael@0:         return false;
michael@0: 
michael@0:     // Build baseline stub frame:
michael@0:     // +===============+
michael@0:     // |    StubPtr    |
michael@0:     // +---------------+
michael@0:     // |   FramePtr    |
michael@0:     // +---------------+
michael@0:     // |     ArgA      |
michael@0:     // +---------------+
michael@0:     // |     ...       |
michael@0:     // +---------------+
michael@0:     // |     Arg0      |
michael@0:     // +---------------+
michael@0:     // |     ThisV     |
michael@0:     // +---------------+
michael@0:     // |  ActualArgC   |
michael@0:     // +---------------+
michael@0:     // |  CalleeToken  |
michael@0:     // +---------------+
michael@0:     // | Descr(BLStub) |
michael@0:     // +---------------+
michael@0:     // |  ReturnAddr   |
michael@0:     // +===============+
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      [BASELINE-STUB FRAME]");
michael@0: 
michael@0:     size_t startOfBaselineStubFrame = builder.framePushed();
michael@0: 
michael@0:     // Write stub pointer.
michael@0:     JS_ASSERT(IsInlinableFallback(icEntry.fallbackStub()));
michael@0:     if (!builder.writePtr(icEntry.fallbackStub(), "StubPtr"))
michael@0:         return false;
michael@0: 
michael@0:     // Write previous frame pointer (saved earlier).
michael@0:     if (!builder.writePtr(prevFramePtr, "PrevFramePtr"))
michael@0:         return false;
michael@0:     prevFramePtr = builder.virtualPointerAtStackOffset(0);
michael@0: 
michael@0:     // Write out actual arguments (and thisv), copied from unpacked stack of BaselineJS frame.
michael@0:     // Arguments are reversed on the BaselineJS frame's stack values.
michael@0:     JS_ASSERT(IsIonInlinablePC(pc));
michael@0:     unsigned actualArgc;
michael@0:     if (needToSaveArgs) {
michael@0:         // For FUNAPPLY or an accessor, the arguments are not on the stack anymore,
michael@0:         // but they are copied in a vector and are written here.
michael@0:         if (op == JSOP_FUNAPPLY)
michael@0:             actualArgc = blFrame->numActualArgs();
michael@0:         else
michael@0:             actualArgc = IsSetPropPC(pc);
michael@0: 
michael@0:         JS_ASSERT(actualArgc + 2 <= exprStackSlots);
michael@0:         JS_ASSERT(savedCallerArgs.length() == actualArgc + 2);
michael@0:         for (unsigned i = 0; i < actualArgc + 1; i++) {
michael@0:             size_t arg = savedCallerArgs.length() - (i + 1);
michael@0:             if (!builder.writeValue(savedCallerArgs[arg], "ArgVal"))
michael@0:                 return false;
michael@0:         }
michael@0:     } else {
michael@0:         actualArgc = GET_ARGC(pc);
michael@0:         if (op == JSOP_FUNCALL) {
michael@0:             JS_ASSERT(actualArgc > 0);
michael@0:             actualArgc--;
michael@0:         }
michael@0: 
michael@0:         JS_ASSERT(actualArgc + 2 <= exprStackSlots);
michael@0:         for (unsigned i = 0; i < actualArgc + 1; i++) {
michael@0:             size_t argSlot = (script->nfixed() + exprStackSlots) - (i + 1);
michael@0:             if (!builder.writeValue(*blFrame->valueSlot(argSlot), "ArgVal"))
michael@0:                 return false;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // In case these arguments need to be copied on the stack again for a rectifier frame,
michael@0:     // save the framePushed values here for later use.
michael@0:     size_t endOfBaselineStubArgs = builder.framePushed();
michael@0: 
michael@0:     // Calculate frame size for descriptor.
michael@0:     size_t baselineStubFrameSize = builder.framePushed() - startOfBaselineStubFrame;
michael@0:     size_t baselineStubFrameDescr = MakeFrameDescriptor((uint32_t) baselineStubFrameSize,
michael@0:                                                         JitFrame_BaselineStub);
michael@0: 
michael@0:     // Push actual argc
michael@0:     if (!builder.writeWord(actualArgc, "ActualArgc"))
michael@0:         return false;
michael@0: 
michael@0:     // Push callee token (must be a JS Function)
michael@0:     Value callee;
michael@0:     if (needToSaveArgs) {
michael@0:         // The arguments of FUNAPPLY or inlined accessors are not writen to the stack.
michael@0:         // So get the callee from the specially saved vector.
michael@0:         callee = savedCallerArgs[0];
michael@0:     } else {
michael@0:         uint32_t calleeStackSlot = exprStackSlots - uint32_t(actualArgc + 2);
michael@0:         size_t calleeOffset = (builder.framePushed() - endOfBaselineJSFrameStack)
michael@0:             + ((exprStackSlots - (calleeStackSlot + 1)) * sizeof(Value));
michael@0:         callee = *builder.valuePointerAtStackOffset(calleeOffset);
michael@0:         IonSpew(IonSpew_BaselineBailouts, "      CalleeStackSlot=%d", (int) calleeStackSlot);
michael@0:     }
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      Callee = %016llx", *((uint64_t *) &callee));
michael@0:     JS_ASSERT(callee.isObject() && callee.toObject().is<JSFunction>());
michael@0:     JSFunction *calleeFun = &callee.toObject().as<JSFunction>();
michael@0:     if (!builder.writePtr(CalleeToToken(calleeFun), "CalleeToken"))
michael@0:         return false;
michael@0:     nextCallee.set(calleeFun);
michael@0: 
michael@0:     // Push BaselineStub frame descriptor
michael@0:     if (!builder.writeWord(baselineStubFrameDescr, "Descriptor"))
michael@0:         return false;
michael@0: 
michael@0:     // Push return address into ICCall_Scripted stub, immediately after the call.
michael@0:     void *baselineCallReturnAddr = GetStubReturnAddress(cx, pc);
michael@0:     JS_ASSERT(baselineCallReturnAddr);
michael@0:     if (!builder.writePtr(baselineCallReturnAddr, "ReturnAddr"))
michael@0:         return false;
michael@0: 
michael@0:     // If actualArgc >= fun->nargs, then we are done.  Otherwise, we need to push on
michael@0:     // a reconstructed rectifier frame.
michael@0:     if (actualArgc >= calleeFun->nargs())
michael@0:         return true;
michael@0: 
michael@0:     // Push a reconstructed rectifier frame.
michael@0:     // +===============+
michael@0:     // |  UndefinedU   |
michael@0:     // +---------------+
michael@0:     // |     ...       |
michael@0:     // +---------------+
michael@0:     // |  Undefined0   |
michael@0:     // +---------------+
michael@0:     // |     ArgA      |
michael@0:     // +---------------+
michael@0:     // |     ...       |
michael@0:     // +---------------+
michael@0:     // |     Arg0      |
michael@0:     // +---------------+
michael@0:     // |     ThisV     |
michael@0:     // +---------------+
michael@0:     // |  ActualArgC   |
michael@0:     // +---------------+
michael@0:     // |  CalleeToken  |
michael@0:     // +---------------+
michael@0:     // |  Descr(Rect)  |
michael@0:     // +---------------+
michael@0:     // |  ReturnAddr   |
michael@0:     // +===============+
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      [RECTIFIER FRAME]");
michael@0: 
michael@0:     size_t startOfRectifierFrame = builder.framePushed();
michael@0: 
michael@0:     // On x86-only, the frame pointer is saved again in the rectifier frame.
michael@0: #if defined(JS_CODEGEN_X86)
michael@0:     if (!builder.writePtr(prevFramePtr, "PrevFramePtr-X86Only"))
michael@0:         return false;
michael@0: #endif
michael@0: 
michael@0:     // Push undefined for missing arguments.
michael@0:     for (unsigned i = 0; i < (calleeFun->nargs() - actualArgc); i++) {
michael@0:         if (!builder.writeValue(UndefinedValue(), "FillerVal"))
michael@0:             return false;
michael@0:     }
michael@0: 
michael@0:     // Copy arguments + thisv from BaselineStub frame.
michael@0:     if (!builder.subtract((actualArgc + 1) * sizeof(Value), "CopiedArgs"))
michael@0:         return false;
michael@0:     BufferPointer<uint8_t> stubArgsEnd =
michael@0:         builder.pointerAtStackOffset<uint8_t>(builder.framePushed() - endOfBaselineStubArgs);
michael@0:     IonSpew(IonSpew_BaselineBailouts, "      MemCpy from %p", stubArgsEnd.get());
michael@0:     memcpy(builder.pointerAtStackOffset<uint8_t>(0).get(), stubArgsEnd.get(),
michael@0:            (actualArgc + 1) * sizeof(Value));
michael@0: 
michael@0:     // Calculate frame size for descriptor.
michael@0:     size_t rectifierFrameSize = builder.framePushed() - startOfRectifierFrame;
michael@0:     size_t rectifierFrameDescr = MakeFrameDescriptor((uint32_t) rectifierFrameSize,
michael@0:                                                      JitFrame_Rectifier);
michael@0: 
michael@0:     // Push actualArgc
michael@0:     if (!builder.writeWord(actualArgc, "ActualArgc"))
michael@0:         return false;
michael@0: 
michael@0:     // Push calleeToken again.
michael@0:     if (!builder.writePtr(CalleeToToken(calleeFun), "CalleeToken"))
michael@0:         return false;
michael@0: 
michael@0:     // Push rectifier frame descriptor
michael@0:     if (!builder.writeWord(rectifierFrameDescr, "Descriptor"))
michael@0:         return false;
michael@0: 
michael@0:     // Push return address into the ArgumentsRectifier code, immediately after the ioncode
michael@0:     // call.
michael@0:     void *rectReturnAddr = cx->runtime()->jitRuntime()->getArgumentsRectifierReturnAddr();
michael@0:     JS_ASSERT(rectReturnAddr);
michael@0:     if (!builder.writePtr(rectReturnAddr, "ReturnAddr"))
michael@0:         return false;
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: uint32_t
michael@0: jit::BailoutIonToBaseline(JSContext *cx, JitActivation *activation, IonBailoutIterator &iter,
michael@0:                           bool invalidate, BaselineBailoutInfo **bailoutInfo,
michael@0:                           const ExceptionBailoutInfo *excInfo)
michael@0: {
michael@0:     JS_ASSERT(bailoutInfo != nullptr);
michael@0:     JS_ASSERT(*bailoutInfo == nullptr);
michael@0: 
michael@0:     TraceLogger *logger = TraceLoggerForMainThread(cx->runtime());
michael@0:     TraceLogStopEvent(logger, TraceLogger::IonMonkey);
michael@0:     TraceLogStartEvent(logger, TraceLogger::Baseline);
michael@0: 
michael@0:     // The caller of the top frame must be one of the following:
michael@0:     //      IonJS - Ion calling into Ion.
michael@0:     //      BaselineStub - Baseline calling into Ion.
michael@0:     //      Entry - Interpreter or other calling into Ion.
michael@0:     //      Rectifier - Arguments rectifier calling into Ion.
michael@0:     JS_ASSERT(iter.isIonJS());
michael@0:     FrameType prevFrameType = iter.prevType();
michael@0:     JS_ASSERT(prevFrameType == JitFrame_IonJS ||
michael@0:               prevFrameType == JitFrame_BaselineStub ||
michael@0:               prevFrameType == JitFrame_Entry ||
michael@0:               prevFrameType == JitFrame_Rectifier);
michael@0: 
michael@0:     // All incoming frames are going to look like this:
michael@0:     //
michael@0:     //      +---------------+
michael@0:     //      |     ...       |
michael@0:     //      +---------------+
michael@0:     //      |     Args      |
michael@0:     //      |     ...       |
michael@0:     //      +---------------+
michael@0:     //      |    ThisV      |
michael@0:     //      +---------------+
michael@0:     //      |  ActualArgC   |
michael@0:     //      +---------------+
michael@0:     //      |  CalleeToken  |
michael@0:     //      +---------------+
michael@0:     //      |  Descriptor   |
michael@0:     //      +---------------+
michael@0:     //      |  ReturnAddr   |
michael@0:     //      +---------------+
michael@0:     //      |    |||||      | <---- Overwrite starting here.
michael@0:     //      |    |||||      |
michael@0:     //      |    |||||      |
michael@0:     //      +---------------+
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts, "Bailing to baseline %s:%u (IonScript=%p) (FrameType=%d)",
michael@0:             iter.script()->filename(), iter.script()->lineno(), (void *) iter.ionScript(),
michael@0:             (int) prevFrameType);
michael@0: 
michael@0:     bool catchingException;
michael@0:     bool propagatingExceptionForDebugMode;
michael@0:     if (excInfo) {
michael@0:         catchingException = excInfo->catchingException();
michael@0:         propagatingExceptionForDebugMode = excInfo->propagatingIonExceptionForDebugMode();
michael@0: 
michael@0:         if (catchingException)
michael@0:             IonSpew(IonSpew_BaselineBailouts, "Resuming in catch or finally block");
michael@0: 
michael@0:         if (propagatingExceptionForDebugMode)
michael@0:             IonSpew(IonSpew_BaselineBailouts, "Resuming in-place for debug mode");
michael@0:     } else {
michael@0:         catchingException = false;
michael@0:         propagatingExceptionForDebugMode = false;
michael@0:     }
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts, "  Reading from snapshot offset %u size %u",
michael@0:             iter.snapshotOffset(), iter.ionScript()->snapshotsListSize());
michael@0: 
michael@0:     if (!excInfo)
michael@0:         iter.ionScript()->incNumBailouts();
michael@0:     iter.script()->updateBaselineOrIonRaw();
michael@0: 
michael@0:     // Allocate buffer to hold stack replacement data.
michael@0:     BaselineStackBuilder builder(iter, 1024);
michael@0:     if (!builder.init())
michael@0:         return BAILOUT_RETURN_FATAL_ERROR;
michael@0:     IonSpew(IonSpew_BaselineBailouts, "  Incoming frame ptr = %p", builder.startFrame());
michael@0: 
michael@0:     SnapshotIterator snapIter(iter);
michael@0: 
michael@0:     RootedFunction callee(cx, iter.maybeCallee());
michael@0:     RootedScript scr(cx, iter.script());
michael@0:     if (callee) {
michael@0:         IonSpew(IonSpew_BaselineBailouts, "  Callee function (%s:%u)",
michael@0:                 scr->filename(), scr->lineno());
michael@0:     } else {
michael@0:         IonSpew(IonSpew_BaselineBailouts, "  No callee!");
michael@0:     }
michael@0: 
michael@0:     if (iter.isConstructing())
michael@0:         IonSpew(IonSpew_BaselineBailouts, "  Constructing!");
michael@0:     else
michael@0:         IonSpew(IonSpew_BaselineBailouts, "  Not constructing!");
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts, "  Restoring frames:");
michael@0:     size_t frameNo = 0;
michael@0: 
michael@0:     // Reconstruct baseline frames using the builder.
michael@0:     RootedScript caller(cx);
michael@0:     jsbytecode *callerPC = nullptr;
michael@0:     RootedFunction fun(cx, callee);
michael@0:     AutoValueVector startFrameFormals(cx);
michael@0: 
michael@0:     RootedScript topCaller(cx);
michael@0:     jsbytecode *topCallerPC = nullptr;
michael@0: 
michael@0:     while (true) {
michael@0:         MOZ_ASSERT(snapIter.instruction()->isResumePoint());
michael@0: 
michael@0:         if (frameNo > 0) {
michael@0:             TraceLogStartEvent(logger, TraceLogCreateTextId(logger, scr));
michael@0:             TraceLogStartEvent(logger, TraceLogger::Baseline);
michael@0:         }
michael@0: 
michael@0:         IonSpew(IonSpew_BaselineBailouts, "    FrameNo %d", frameNo);
michael@0: 
michael@0:         // If we are bailing out to a catch or finally block in this frame,
michael@0:         // pass excInfo to InitFromBailout and don't unpack any other frames.
michael@0:         bool handleException = (catchingException && excInfo->frameNo() == frameNo);
michael@0: 
michael@0:         // We also need to pass excInfo if we're bailing out in place for
michael@0:         // debug mode.
michael@0:         bool passExcInfo = handleException || propagatingExceptionForDebugMode;
michael@0: 
michael@0:         jsbytecode *callPC = nullptr;
michael@0:         RootedFunction nextCallee(cx, nullptr);
michael@0:         if (!InitFromBailout(cx, caller, callerPC, fun, scr, iter.ionScript(),
michael@0:                              snapIter, invalidate, builder, startFrameFormals,
michael@0:                              &nextCallee, &callPC, passExcInfo ? excInfo : nullptr))
michael@0:         {
michael@0:             return BAILOUT_RETURN_FATAL_ERROR;
michael@0:         }
michael@0: 
michael@0:         if (!snapIter.moreFrames()) {
michael@0:             JS_ASSERT(!callPC);
michael@0:             break;
michael@0:         }
michael@0: 
michael@0:         if (handleException)
michael@0:             break;
michael@0: 
michael@0:         JS_ASSERT(nextCallee);
michael@0:         JS_ASSERT(callPC);
michael@0:         caller = scr;
michael@0:         callerPC = callPC;
michael@0:         fun = nextCallee;
michael@0:         scr = fun->existingScriptForInlinedFunction();
michael@0: 
michael@0:         // Save top caller info for adjusting SPS frames later.
michael@0:         if (!topCaller) {
michael@0:             JS_ASSERT(frameNo == 0);
michael@0:             topCaller = caller;
michael@0:             topCallerPC = callerPC;
michael@0:         }
michael@0: 
michael@0:         frameNo++;
michael@0: 
michael@0:         snapIter.nextInstruction();
michael@0:     }
michael@0:     IonSpew(IonSpew_BaselineBailouts, "  Done restoring frames");
michael@0: 
michael@0:     // If there were multiple inline frames unpacked, and inline frame profiling
michael@0:     // is off, then the current top SPS frame is for the outermost caller, and
michael@0:     // has an uninitialized PC.  Initialize it now.
michael@0:     if (frameNo > 0 && !js_JitOptions.profileInlineFrames)
michael@0:         cx->runtime()->spsProfiler.updatePC(topCaller, topCallerPC);
michael@0: 
michael@0:     BailoutKind bailoutKind = snapIter.bailoutKind();
michael@0: 
michael@0:     if (!startFrameFormals.empty()) {
michael@0:         // Set the first frame's formals, see the comment in InitFromBailout.
michael@0:         Value *argv = builder.startFrame()->argv() + 1; // +1 to skip |this|.
michael@0:         mozilla::PodCopy(argv, startFrameFormals.begin(), startFrameFormals.length());
michael@0:     }
michael@0: 
michael@0:     // Do stack check.
michael@0:     bool overRecursed = false;
michael@0:     BaselineBailoutInfo *info = builder.info();
michael@0:     uint8_t *newsp = info->incomingStack - (info->copyStackTop - info->copyStackBottom);
michael@0: #ifdef JS_ARM_SIMULATOR
michael@0:     if (Simulator::Current()->overRecursed(uintptr_t(newsp)))
michael@0:         overRecursed = true;
michael@0: #else
michael@0:     JS_CHECK_RECURSION_WITH_SP_DONT_REPORT(cx, newsp, overRecursed = true);
michael@0: #endif
michael@0:     if (overRecursed) {
michael@0:         IonSpew(IonSpew_BaselineBailouts, "  Overrecursion check failed!");
michael@0:         return BAILOUT_RETURN_OVERRECURSED;
michael@0:     }
michael@0: 
michael@0:     // Take the reconstructed baseline stack so it doesn't get freed when builder destructs.
michael@0:     info = builder.takeBuffer();
michael@0:     info->numFrames = frameNo + 1;
michael@0:     info->bailoutKind = bailoutKind;
michael@0:     *bailoutInfo = info;
michael@0:     return BAILOUT_RETURN_OK;
michael@0: }
michael@0: 
michael@0: static bool
michael@0: HandleBoundsCheckFailure(JSContext *cx, HandleScript outerScript, HandleScript innerScript)
michael@0: {
michael@0:     IonSpew(IonSpew_Bailouts, "Bounds check failure %s:%d, inlined into %s:%d",
michael@0:             innerScript->filename(), innerScript->lineno(),
michael@0:             outerScript->filename(), outerScript->lineno());
michael@0: 
michael@0:     JS_ASSERT(!outerScript->ionScript()->invalidated());
michael@0: 
michael@0:     // TODO: Currently this mimic's Ion's handling of this case.  Investigate setting
michael@0:     // the flag on innerScript as opposed to outerScript, and maybe invalidating both
michael@0:     // inner and outer scripts, instead of just the outer one.
michael@0:     if (!outerScript->failedBoundsCheck())
michael@0:         outerScript->setFailedBoundsCheck();
michael@0:     IonSpew(IonSpew_BaselineBailouts, "Invalidating due to bounds check failure");
michael@0:     return Invalidate(cx, outerScript);
michael@0: }
michael@0: 
michael@0: static bool
michael@0: HandleShapeGuardFailure(JSContext *cx, HandleScript outerScript, HandleScript innerScript)
michael@0: {
michael@0:     IonSpew(IonSpew_Bailouts, "Shape guard failure %s:%d, inlined into %s:%d",
michael@0:             innerScript->filename(), innerScript->lineno(),
michael@0:             outerScript->filename(), outerScript->lineno());
michael@0: 
michael@0:     JS_ASSERT(!outerScript->ionScript()->invalidated());
michael@0: 
michael@0:     // TODO: Currently this mimic's Ion's handling of this case.  Investigate setting
michael@0:     // the flag on innerScript as opposed to outerScript, and maybe invalidating both
michael@0:     // inner and outer scripts, instead of just the outer one.
michael@0:     outerScript->setFailedShapeGuard();
michael@0:     IonSpew(IonSpew_BaselineBailouts, "Invalidating due to shape guard failure");
michael@0:     return Invalidate(cx, outerScript);
michael@0: }
michael@0: 
michael@0: static bool
michael@0: HandleBaselineInfoBailout(JSContext *cx, JSScript *outerScript, JSScript *innerScript)
michael@0: {
michael@0:     IonSpew(IonSpew_Bailouts, "Baseline info failure %s:%d, inlined into %s:%d",
michael@0:             innerScript->filename(), innerScript->lineno(),
michael@0:             outerScript->filename(), outerScript->lineno());
michael@0: 
michael@0:     JS_ASSERT(!outerScript->ionScript()->invalidated());
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts, "Invalidating due to invalid baseline info");
michael@0:     return Invalidate(cx, outerScript);
michael@0: }
michael@0: 
michael@0: static bool
michael@0: CopyFromRematerializedFrame(JSContext *cx, JitActivation *act, uint8_t *fp, size_t inlineDepth,
michael@0:                             BaselineFrame *frame)
michael@0: {
michael@0:     RematerializedFrame *rematFrame = act->lookupRematerializedFrame(fp, inlineDepth);
michael@0: 
michael@0:     // We might not have rematerialized a frame if the user never requested a
michael@0:     // Debugger.Frame for it.
michael@0:     if (!rematFrame)
michael@0:         return true;
michael@0: 
michael@0:     MOZ_ASSERT(rematFrame->script() == frame->script());
michael@0:     MOZ_ASSERT(rematFrame->numActualArgs() == frame->numActualArgs());
michael@0: 
michael@0:     frame->setScopeChain(rematFrame->scopeChain());
michael@0:     frame->thisValue() = rematFrame->thisValue();
michael@0: 
michael@0:     for (unsigned i = 0; i < frame->numActualArgs(); i++)
michael@0:         frame->argv()[i] = rematFrame->argv()[i];
michael@0: 
michael@0:     for (size_t i = 0; i < frame->script()->nfixed(); i++)
michael@0:         *frame->valueSlot(i) = rematFrame->locals()[i];
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts,
michael@0:             "  Copied from rematerialized frame at (%p,%u)",
michael@0:             fp, inlineDepth);
michael@0: 
michael@0:     if (cx->compartment()->debugMode())
michael@0:         return Debugger::handleIonBailout(cx, rematFrame, frame);
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: uint32_t
michael@0: jit::FinishBailoutToBaseline(BaselineBailoutInfo *bailoutInfo)
michael@0: {
michael@0:     // The caller pushes R0 and R1 on the stack without rooting them.
michael@0:     // Since GC here is very unlikely just suppress it.
michael@0:     JSContext *cx = GetJSContextFromJitCode();
michael@0:     js::gc::AutoSuppressGC suppressGC(cx);
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts, "  Done restoring frames");
michael@0: 
michael@0:     // Check that we can get the current script's PC.
michael@0: #ifdef DEBUG
michael@0:     jsbytecode *pc;
michael@0:     cx->currentScript(&pc);
michael@0:     IonSpew(IonSpew_BaselineBailouts, "  Got pc=%p", pc);
michael@0: #endif
michael@0: 
michael@0:     uint32_t numFrames = bailoutInfo->numFrames;
michael@0:     JS_ASSERT(numFrames > 0);
michael@0:     BailoutKind bailoutKind = bailoutInfo->bailoutKind;
michael@0: 
michael@0:     // Free the bailout buffer.
michael@0:     js_free(bailoutInfo);
michael@0:     bailoutInfo = nullptr;
michael@0: 
michael@0:     // Ensure the frame has a call object if it needs one. If the scope chain
michael@0:     // is nullptr, we will enter baseline code at the prologue so no need to do
michael@0:     // anything in that case.
michael@0:     BaselineFrame *topFrame = GetTopBaselineFrame(cx);
michael@0:     if (topFrame->scopeChain() && !EnsureHasScopeObjects(cx, topFrame))
michael@0:         return false;
michael@0: 
michael@0:     // Create arguments objects for bailed out frames, to maintain the invariant
michael@0:     // that script->needsArgsObj() implies frame->hasArgsObj().
michael@0:     RootedScript innerScript(cx, nullptr);
michael@0:     RootedScript outerScript(cx, nullptr);
michael@0: 
michael@0:     JS_ASSERT(cx->currentlyRunningInJit());
michael@0:     JitFrameIterator iter(cx);
michael@0:     uint8_t *outerFp = nullptr;
michael@0: 
michael@0:     uint32_t frameno = 0;
michael@0:     while (frameno < numFrames) {
michael@0:         JS_ASSERT(!iter.isIonJS());
michael@0: 
michael@0:         if (iter.isBaselineJS()) {
michael@0:             BaselineFrame *frame = iter.baselineFrame();
michael@0:             MOZ_ASSERT(frame->script()->hasBaselineScript());
michael@0: 
michael@0:             // If the frame doesn't even have a scope chain set yet, then it's resuming
michael@0:             // into the the prologue before the scope chain is initialized.  Any
michael@0:             // necessary args object will also be initialized there.
michael@0:             if (frame->scopeChain() && frame->script()->needsArgsObj()) {
michael@0:                 ArgumentsObject *argsObj;
michael@0:                 if (frame->hasArgsObj()) {
michael@0:                     argsObj = &frame->argsObj();
michael@0:                 } else {
michael@0:                     argsObj = ArgumentsObject::createExpected(cx, frame);
michael@0:                     if (!argsObj)
michael@0:                         return false;
michael@0:                 }
michael@0: 
michael@0:                 // The arguments is a local binding and needsArgsObj does not
michael@0:                 // check if it is clobbered. Ensure that the local binding
michael@0:                 // restored during bailout before storing the arguments object
michael@0:                 // to the slot.
michael@0:                 RootedScript script(cx, frame->script());
michael@0:                 SetFrameArgumentsObject(cx, frame, script, argsObj);
michael@0:             }
michael@0: 
michael@0:             if (frameno == 0)
michael@0:                 innerScript = frame->script();
michael@0: 
michael@0:             if (frameno == numFrames - 1) {
michael@0:                 outerScript = frame->script();
michael@0:                 outerFp = iter.fp();
michael@0:             }
michael@0: 
michael@0:             frameno++;
michael@0:         }
michael@0: 
michael@0:         ++iter;
michael@0:     }
michael@0: 
michael@0:     MOZ_ASSERT(innerScript);
michael@0:     MOZ_ASSERT(outerScript);
michael@0:     MOZ_ASSERT(outerFp);
michael@0: 
michael@0:     // If we rematerialized Ion frames due to debug mode toggling, copy their
michael@0:     // values into the baseline frame. We need to do this even when debug mode
michael@0:     // is off, as we should respect the mutations made while debug mode was
michael@0:     // on.
michael@0:     JitActivation *act = cx->mainThread().activation()->asJit();
michael@0:     if (act->hasRematerializedFrame(outerFp)) {
michael@0:         JitFrameIterator iter(cx);
michael@0:         size_t inlineDepth = numFrames;
michael@0:         while (inlineDepth > 0) {
michael@0:             if (iter.isBaselineJS() &&
michael@0:                 !CopyFromRematerializedFrame(cx, act, outerFp, --inlineDepth,
michael@0:                                              iter.baselineFrame()))
michael@0:             {
michael@0:                 return false;
michael@0:             }
michael@0:             ++iter;
michael@0:         }
michael@0: 
michael@0:         // After copying from all the rematerialized frames, remove them from
michael@0:         // the table to keep the table up to date.
michael@0:         act->removeRematerializedFrame(outerFp);
michael@0:     }
michael@0: 
michael@0:     IonSpew(IonSpew_BaselineBailouts,
michael@0:             "  Restored outerScript=(%s:%u,%u) innerScript=(%s:%u,%u) (bailoutKind=%u)",
michael@0:             outerScript->filename(), outerScript->lineno(), outerScript->getUseCount(),
michael@0:             innerScript->filename(), innerScript->lineno(), innerScript->getUseCount(),
michael@0:             (unsigned) bailoutKind);
michael@0: 
michael@0:     switch (bailoutKind) {
michael@0:       case Bailout_Normal:
michael@0:         // Do nothing.
michael@0:         break;
michael@0:       case Bailout_ArgumentCheck:
michael@0:         // Do nothing, bailout will resume before the argument monitor ICs.
michael@0:         break;
michael@0:       case Bailout_BoundsCheck:
michael@0:         if (!HandleBoundsCheckFailure(cx, outerScript, innerScript))
michael@0:             return false;
michael@0:         break;
michael@0:       case Bailout_ShapeGuard:
michael@0:         if (!HandleShapeGuardFailure(cx, outerScript, innerScript))
michael@0:             return false;
michael@0:         break;
michael@0:       case Bailout_BaselineInfo:
michael@0:         if (!HandleBaselineInfoBailout(cx, outerScript, innerScript))
michael@0:             return false;
michael@0:         break;
michael@0:       case Bailout_IonExceptionDebugMode:
michael@0:         // Return false to resume in HandleException with reconstructed
michael@0:         // baseline frame.
michael@0:         return false;
michael@0:       default:
michael@0:         MOZ_ASSUME_UNREACHABLE("Unknown bailout kind!");
michael@0:     }
michael@0: 
michael@0:     if (!CheckFrequentBailouts(cx, outerScript))
michael@0:         return false;
michael@0: 
michael@0:     return true;
michael@0: }