Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1414 insertions, 0 deletions

diff --git a/js/src/jit/MIRGraph.cpp b/js/src/jit/MIRGraph.cpp
new file mode 100644
index 0000000000..86a2bf4ad3
--- /dev/null
+++ b/js/src/jit/MIRGraph.cpp
@@ -0,0 +1,1414 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "jit/MIRGraph.h"
+
+#include "jit/CompileInfo.h"
+#include "jit/InlineScriptTree.h"
+#include "jit/IonOptimizationLevels.h"
+#include "jit/JitSpewer.h"
+#include "jit/MIR.h"
+#include "jit/MIRGenerator.h"
+
+using namespace js;
+using namespace js::jit;
+
+MIRGenerator::MIRGenerator(CompileRealm* realm,
+                           const JitCompileOptions& options,
+                           TempAllocator* alloc, MIRGraph* graph,
+                           const CompileInfo* info,
+                           const OptimizationInfo* optimizationInfo)
+    : realm(realm),
+      runtime(realm ? realm->runtime() : nullptr),
+      outerInfo_(info),
+      optimizationInfo_(optimizationInfo),
+      alloc_(alloc),
+      graph_(graph),
+      offThreadStatus_(Ok()),
+      cancelBuild_(false),
+      wasmMaxStackArgBytes_(0),
+      needsOverrecursedCheck_(false),
+      needsStaticStackAlignment_(false),
+      instrumentedProfiling_(false),
+      instrumentedProfilingIsCached_(false),
+      stringsCanBeInNursery_(realm ? realm->zone()->canNurseryAllocateStrings()
+                                   : false),
+      bigIntsCanBeInNursery_(realm ? realm->zone()->canNurseryAllocateBigInts()
+                                   : false),
+      minWasmHeapLength_(0),
+      options(options),
+      gs_(alloc) {}
+
+bool MIRGenerator::licmEnabled() const {
+  return optimizationInfo().licmEnabled() && !disableLICM_ &&
+         !outerInfo().hadLICMInvalidation();
+}
+
+mozilla::GenericErrorResult<AbortReason> MIRGenerator::abort(AbortReason r) {
+  if (JitSpewEnabled(JitSpew_IonAbort)) {
+    switch (r) {
+      case AbortReason::Alloc:
+        JitSpew(JitSpew_IonAbort, "AbortReason::Alloc");
+        break;
+      case AbortReason::Disable:
+        JitSpew(JitSpew_IonAbort, "AbortReason::Disable");
+        break;
+      case AbortReason::Error:
+        JitSpew(JitSpew_IonAbort, "AbortReason::Error");
+        break;
+      case AbortReason::NoAbort:
+        MOZ_CRASH("Abort with AbortReason::NoAbort");
+        break;
+    }
+  }
+  return Err(std::move(r));
+}
+
+mozilla::GenericErrorResult<AbortReason> MIRGenerator::abortFmt(
+    AbortReason r, const char* message, va_list ap) {
+  JitSpewVA(JitSpew_IonAbort, message, ap);
+  return Err(std::move(r));
+}
+
+mozilla::GenericErrorResult<AbortReason> MIRGenerator::abort(
+    AbortReason r, const char* message, ...) {
+  va_list ap;
+  va_start(ap, message);
+  auto forward = abortFmt(r, message, ap);
+  va_end(ap);
+  return forward;
+}
+
+void MIRGraph::addBlock(MBasicBlock* block) {
+  MOZ_ASSERT(block);
+  block->setId(blockIdGen_++);
+  blocks_.pushBack(block);
+  numBlocks_++;
+}
+
+void MIRGraph::insertBlockAfter(MBasicBlock* at, MBasicBlock* block) {
+  block->setId(blockIdGen_++);
+  blocks_.insertAfter(at, block);
+  numBlocks_++;
+}
+
+void MIRGraph::insertBlockBefore(MBasicBlock* at, MBasicBlock* block) {
+  block->setId(blockIdGen_++);
+  blocks_.insertBefore(at, block);
+  numBlocks_++;
+}
+
+void MIRGraph::removeBlock(MBasicBlock* block) {
+  // Remove a block from the graph. It will also cleanup the block.
+
+  if (block == osrBlock_) {
+    osrBlock_ = nullptr;
+  }
+
+  if (returnAccumulator_) {
+    size_t i = 0;
+    while (i < returnAccumulator_->length()) {
+      if ((*returnAccumulator_)[i] == block) {
+        returnAccumulator_->erase(returnAccumulator_->begin() + i);
+      } else {
+        i++;
+      }
+    }
+  }
+
+  block->clear();
+  block->markAsDead();
+
+  if (block->isInList()) {
+    blocks_.remove(block);
+    numBlocks_--;
+  }
+}
+
+void MIRGraph::unmarkBlocks() {
+  for (MBasicBlockIterator i(blocks_.begin()); i != blocks_.end(); i++) {
+    i->unmark();
+  }
+}
+
+MBasicBlock* MBasicBlock::New(MIRGraph& graph, size_t stackDepth,
+                              const CompileInfo& info, MBasicBlock* maybePred,
+                              BytecodeSite* site, Kind kind) {
+  MOZ_ASSERT(site->pc() != nullptr);
+
+  MBasicBlock* block = new (graph.alloc()) MBasicBlock(graph, info, site, kind);
+  if (!block->init()) {
+    return nullptr;
+  }
+
+  if (!block->inherit(graph.alloc(), stackDepth, maybePred, 0)) {
+    return nullptr;
+  }
+
+  return block;
+}
+
+MBasicBlock* MBasicBlock::NewPopN(MIRGraph& graph, const CompileInfo& info,
+                                  MBasicBlock* pred, BytecodeSite* site,
+                                  Kind kind, uint32_t popped) {
+  MOZ_ASSERT(site->pc() != nullptr);
+
+  MBasicBlock* block = new (graph.alloc()) MBasicBlock(graph, info, site, kind);
+  if (!block->init()) {
+    return nullptr;
+  }
+
+  if (!block->inherit(graph.alloc(), pred->stackDepth(), pred, popped)) {
+    return nullptr;
+  }
+
+  return block;
+}
+
+MBasicBlock* MBasicBlock::NewPendingLoopHeader(MIRGraph& graph,
+                                               const CompileInfo& info,
+                                               MBasicBlock* pred,
+                                               BytecodeSite* site) {
+  MOZ_ASSERT(site->pc() != nullptr);
+
+  MBasicBlock* block =
+      new (graph.alloc()) MBasicBlock(graph, info, site, PENDING_LOOP_HEADER);
+  if (!block->init()) {
+    return nullptr;
+  }
+
+  if (!block->inherit(graph.alloc(), pred->stackDepth(), pred, 0)) {
+    return nullptr;
+  }
+
+  return block;
+}
+
+MBasicBlock* MBasicBlock::NewSplitEdge(MIRGraph& graph, MBasicBlock* pred,
+                                       size_t predEdgeIdx, MBasicBlock* succ) {
+  MBasicBlock* split = nullptr;
+  if (!succ->pc()) {
+    // The predecessor does not have a PC, this is a Wasm compilation.
+    split = MBasicBlock::New(graph, succ->info(), pred, SPLIT_EDGE);
+    if (!split) {
+      return nullptr;
+    }
+
+    // Insert the split edge block in-between.
+    split->end(MGoto::New(graph.alloc(), succ));
+  } else {
+    // The predecessor has a PC, this is a Warp compilation.
+    MResumePoint* succEntry = succ->entryResumePoint();
+
+    BytecodeSite* site =
+        new (graph.alloc()) BytecodeSite(succ->trackedTree(), succEntry->pc());
+    split =
+        new (graph.alloc()) MBasicBlock(graph, succ->info(), site, SPLIT_EDGE);
+
+    if (!split->init()) {
+      return nullptr;
+    }
+
+    // A split edge is used to simplify the graph to avoid having a
+    // predecessor with multiple successors as well as a successor with
+    // multiple predecessors.  As instructions can be moved in this
+    // split-edge block, we need to give this block a resume point. To do
+    // so, we copy the entry resume points of the successor and filter the
+    // phis to keep inputs from the current edge.
+
+    // Propagate the caller resume point from the inherited block.
+    split->callerResumePoint_ = succ->callerResumePoint();
+
+    // Split-edge are created after the interpreter stack emulation. Thus,
+    // there is no need for creating slots.
+    split->stackPosition_ = succEntry->stackDepth();
+
+    // Create a resume point using our initial stack position.
+    MResumePoint* splitEntry = new (graph.alloc())
+        MResumePoint(split, succEntry->pc(), ResumeMode::ResumeAt);
+    if (!splitEntry->init(graph.alloc())) {
+      return nullptr;
+    }
+    split->entryResumePoint_ = splitEntry;
+
+    // Insert the split edge block in-between.
+    split->end(MGoto::New(graph.alloc(), succ));
+
+    // The target entry resume point might have phi operands, keep the
+    // operands of the phi coming from our edge.
+    size_t succEdgeIdx = succ->indexForPredecessor(pred);
+
+    for (size_t i = 0, e = splitEntry->numOperands(); i < e; i++) {
+      MDefinition* def = succEntry->getOperand(i);
+      // This early in the pipeline, we have no recover instructions in
+      // any entry resume point.
+      if (def->block() == succ) {
+        if (def->isPhi()) {
+          def = def->toPhi()->getOperand(succEdgeIdx);
+        } else {
+          // The phi-operand may already have been optimized out.
+          MOZ_ASSERT(def->isConstant());
+          MOZ_ASSERT(def->type() == MIRType::MagicOptimizedOut);
+
+          def = split->optimizedOutConstant(graph.alloc());
+        }
+      }
+
+      splitEntry->initOperand(i, def);
+    }
+
+    // This is done in the New variant for wasm, so we cannot keep this
+    // line below, where the rest of the graph is modified.
+    if (!split->predecessors_.append(pred)) {
+      return nullptr;
+    }
+  }
+
+  split->setLoopDepth(succ->loopDepth());
+
+  graph.insertBlockAfter(pred, split);
+
+  pred->replaceSuccessor(predEdgeIdx, split);
+  succ->replacePredecessor(pred, split);
+  return split;
+}
+
+void MBasicBlock::moveToNewBlock(MInstruction* ins, MBasicBlock* dst) {
+  MOZ_ASSERT(ins->block() == this);
+  MOZ_ASSERT(!dst->hasLastIns());
+  instructions_.remove(ins);
+  ins->setInstructionBlock(dst, dst->trackedSite());
+  if (MResumePoint* rp = ins->resumePoint()) {
+    removeResumePoint(rp);
+    dst->addResumePoint(rp);
+    rp->setBlock(dst);
+  }
+  dst->instructions_.pushBack(ins);
+}
+
+void MBasicBlock::moveOuterResumePointTo(MBasicBlock* dest) {
+  if (MResumePoint* outer = outerResumePoint()) {
+    removeResumePoint(outer);
+    outerResumePoint_ = nullptr;
+    dest->setOuterResumePoint(outer);
+    dest->addResumePoint(outer);
+    outer->setBlock(dest);
+  }
+}
+
+bool MBasicBlock::wrapInstructionInFastpath(MInstruction* ins,
+                                            MInstruction* fastpath,
+                                            MInstruction* condition) {
+  MOZ_ASSERT(ins->block() == this);
+  MOZ_ASSERT(!ins->isControlInstruction());
+
+  MInstructionIterator rest(begin(ins));
+  rest++;
+
+  MResumePoint* resumeBeforeIns = activeResumePoint(ins);
+  MResumePoint* resumeAfterIns = activeResumePoint(*rest);
+
+  // Create the join block.
+  MBasicBlock* join = MBasicBlock::NewInternal(graph_, this, resumeAfterIns);
+  if (!join) {
+    return false;
+  }
+
+  // Update the successors of the current block.
+  for (uint32_t i = 0; i < numSuccessors(); i++) {
+    getSuccessor(i)->replacePredecessor(this, join);
+  }
+  if (successorWithPhis()) {
+    join->setSuccessorWithPhis(successorWithPhis(), positionInPhiSuccessor());
+    clearSuccessorWithPhis();
+  }
+
+  // Copy all instructions after |ins| into the join block.
+  while (rest != end()) {
+    MInstruction* ins = *rest++;
+    moveToNewBlock(ins, join);
+  }
+  MOZ_ASSERT(!hasLastIns());
+  MOZ_ASSERT(join->hasLastIns());
+
+  graph_.insertBlockAfter(this, join);
+
+  // Create the fast path block.
+  MBasicBlock* fastpathBlock =
+      MBasicBlock::NewInternal(graph_, this, resumeBeforeIns);
+  if (!fastpathBlock) {
+    return false;
+  }
+  graph_.insertBlockAfter(this, fastpathBlock);
+  fastpathBlock->add(fastpath);
+  fastpathBlock->end(MGoto::New(graph_.alloc(), join));
+
+  // Create the slowpath block.
+  MBasicBlock* slowpathBlock =
+      MBasicBlock::NewInternal(graph_, this, resumeBeforeIns);
+  if (!slowpathBlock) {
+    return false;
+  }
+  graph_.insertBlockAfter(fastpathBlock, slowpathBlock);
+  moveToNewBlock(ins, slowpathBlock);
+  slowpathBlock->end(MGoto::New(graph_.alloc(), join));
+
+  // Connect current block to fastpath and slowpath.
+  add(condition);
+  end(MTest::New(graph_.alloc(), condition, fastpathBlock, slowpathBlock));
+
+  // Update predecessors.
+  if (!fastpathBlock->addPredecessorWithoutPhis(this) ||
+      !slowpathBlock->addPredecessorWithoutPhis(this) ||
+      !join->addPredecessorWithoutPhis(fastpathBlock) ||
+      !join->addPredecessorWithoutPhis(slowpathBlock)) {
+    return false;
+  }
+
+  if (ins->hasUses()) {
+    // Insert phi.
+    MPhi* phi = MPhi::New(graph_.alloc());
+    if (!phi->reserveLength(2)) {
+      return false;
+    }
+    phi->addInput(fastpath);
+    fastpathBlock->setSuccessorWithPhis(join, 0);
+    phi->addInput(ins);
+    slowpathBlock->setSuccessorWithPhis(join, 1);
+    join->addPhi(phi);
+
+    for (MUseIterator i(ins->usesBegin()), e(ins->usesEnd()); i != e;) {
+      MUse* use = *i++;
+      if (use->consumer() != phi && use->consumer() != ins->resumePoint()) {
+        use->replaceProducer(phi);
+      }
+    }
+  }
+
+  moveOuterResumePointTo(join);
+
+  return true;
+}
+
+MBasicBlock* MBasicBlock::NewInternal(MIRGraph& graph, MBasicBlock* orig,
+                                      MResumePoint* resumePoint) {
+  jsbytecode* pc = IsResumeAfter(resumePoint->mode())
+                       ? GetNextPc(resumePoint->pc())
+                       : resumePoint->pc();
+
+  BytecodeSite* site =
+      new (graph.alloc()) BytecodeSite(orig->trackedTree(), pc);
+  MBasicBlock* block =
+      new (graph.alloc()) MBasicBlock(graph, orig->info(), site, INTERNAL);
+  if (!block->init()) {
+    return nullptr;
+  }
+
+  // Propagate the caller resume point from the original block.
+  block->callerResumePoint_ = orig->callerResumePoint();
+
+  // Copy the resume point.
+  block->stackPosition_ = resumePoint->stackDepth();
+  MResumePoint* entryResumePoint =
+      new (graph.alloc()) MResumePoint(block, pc, ResumeMode::ResumeAt);
+  if (!entryResumePoint->init(graph.alloc())) {
+    return nullptr;
+  }
+  for (size_t i = 0; i < resumePoint->stackDepth(); i++) {
+    entryResumePoint->initOperand(i, resumePoint->getOperand(i));
+  }
+  block->entryResumePoint_ = entryResumePoint;
+
+  block->setLoopDepth(orig->loopDepth());
+
+  return block;
+}
+
+MBasicBlock* MBasicBlock::New(MIRGraph& graph, const CompileInfo& info,
+                              MBasicBlock* pred, Kind kind) {
+  BytecodeSite* site = new (graph.alloc()) BytecodeSite();
+  MBasicBlock* block = new (graph.alloc()) MBasicBlock(graph, info, site, kind);
+  if (!block->init()) {
+    return nullptr;
+  }
+
+  if (pred) {
+    block->stackPosition_ = pred->stackPosition_;
+
+    if (block->kind_ == PENDING_LOOP_HEADER) {
+      size_t nphis = block->stackPosition_;
+
+      size_t nfree = graph.phiFreeListLength();
+
+      TempAllocator& alloc = graph.alloc();
+      MPhi* phis = nullptr;
+      if (nphis > nfree) {
+        phis = alloc.allocateArray<MPhi>(nphis - nfree);
+        if (!phis) {
+          return nullptr;
+        }
+      }
+
+      // Note: Phis are inserted in the same order as the slots.
+      for (size_t i = 0; i < nphis; i++) {
+        MDefinition* predSlot = pred->getSlot(i);
+
+        MOZ_ASSERT(predSlot->type() != MIRType::Value);
+
+        MPhi* phi;
+        if (i < nfree) {
+          phi = graph.takePhiFromFreeList();
+        } else {
+          phi = phis + (i - nfree);
+        }
+        new (phi) MPhi(alloc, predSlot->type());
+
+        phi->addInlineInput(predSlot);
+
+        // Add append Phis in the block.
+        block->addPhi(phi);
+        block->setSlot(i, phi);
+      }
+    } else {
+      if (!block->ensureHasSlots(0)) {
+        return nullptr;
+      }
+      block->copySlots(pred);
+    }
+
+    if (!block->predecessors_.append(pred)) {
+      return nullptr;
+    }
+  }
+
+  return block;
+}
+
+// Create an empty and unreachable block which jumps to |header|. Used
+// when the normal entry into a loop is removed (but the loop is still
+// reachable due to OSR) to preserve the invariant that every loop
+// header has two predecessors, which is needed for building the
+// dominator tree. The new block is inserted immediately before the
+// header, which preserves the graph ordering (post-order/RPO). These
+// blocks will all be removed before lowering.
+MBasicBlock* MBasicBlock::NewFakeLoopPredecessor(MIRGraph& graph,
+                                                 MBasicBlock* header) {
+  MOZ_ASSERT(graph.osrBlock());
+
+  MBasicBlock* backedge = header->backedge();
+  MBasicBlock* fake = MBasicBlock::New(graph, header->info(), nullptr,
+                                       MBasicBlock::FAKE_LOOP_PRED);
+  if (!fake) {
+    return nullptr;
+  }
+
+  graph.insertBlockBefore(header, fake);
+  fake->setUnreachable();
+
+  // Create fake defs to use as inputs for any phis in |header|.
+  for (MPhiIterator iter(header->phisBegin()), end(header->phisEnd());
+       iter != end; ++iter) {
+    if (!graph.alloc().ensureBallast()) {
+      return nullptr;
+    }
+    MPhi* phi = *iter;
+    auto* fakeDef = MUnreachableResult::New(graph.alloc(), phi->type());
+    fake->add(fakeDef);
+    if (!phi->addInputSlow(fakeDef)) {
+      return nullptr;
+    }
+  }
+
+  fake->end(MGoto::New(graph.alloc(), header));
+
+  if (!header->addPredecessorWithoutPhis(fake)) {
+    return nullptr;
+  }
+
+  // The backedge is always the last predecessor, but we have added a
+  // new pred. Restore |backedge| as |header|'s loop backedge.
+  header->clearLoopHeader();
+  header->setLoopHeader(backedge);
+
+  return fake;
+}
+
+void MIRGraph::removeFakeLoopPredecessors() {
+  MOZ_ASSERT(osrBlock());
+  size_t id = 0;
+  for (ReversePostorderIterator it = rpoBegin(); it != rpoEnd();) {
+    MBasicBlock* block = *it++;
+    if (block->isFakeLoopPred()) {
+      MOZ_ASSERT(block->unreachable());
+      MBasicBlock* succ = block->getSingleSuccessor();
+      succ->removePredecessor(block);
+      removeBlock(block);
+    } else {
+      block->setId(id++);
+    }
+  }
+#ifdef DEBUG
+  canBuildDominators_ = false;
+#endif
+}
+
+MBasicBlock::MBasicBlock(MIRGraph& graph, const CompileInfo& info,
+                         BytecodeSite* site, Kind kind)
+    : graph_(graph),
+      info_(info),
+      predecessors_(graph.alloc()),
+      stackPosition_(info_.firstStackSlot()),
+      id_(0),
+      domIndex_(0),
+      numDominated_(0),
+      lir_(nullptr),
+      callerResumePoint_(nullptr),
+      entryResumePoint_(nullptr),
+      outerResumePoint_(nullptr),
+      successorWithPhis_(nullptr),
+      positionInPhiSuccessor_(0),
+      loopDepth_(0),
+      kind_(kind),
+      mark_(false),
+      immediatelyDominated_(graph.alloc()),
+      immediateDominator_(nullptr),
+      trackedSite_(site),
+      lineno_(0u),
+      columnIndex_(0u) {
+  MOZ_ASSERT(trackedSite_, "trackedSite_ is non-nullptr");
+}
+
+bool MBasicBlock::init() { return slots_.init(graph_.alloc(), info_.nslots()); }
+
+bool MBasicBlock::increaseSlots(size_t num) {
+  return slots_.growBy(graph_.alloc(), num);
+}
+
+bool MBasicBlock::ensureHasSlots(size_t num) {
+  size_t depth = stackDepth() + num;
+  if (depth > nslots()) {
+    if (!increaseSlots(depth - nslots())) {
+      return false;
+    }
+  }
+  return true;
+}
+
+void MBasicBlock::copySlots(MBasicBlock* from) {
+  MOZ_ASSERT(stackPosition_ <= from->stackPosition_);
+  MOZ_ASSERT(stackPosition_ <= nslots());
+
+  MDefinition** thisSlots = slots_.begin();
+  MDefinition** fromSlots = from->slots_.begin();
+  for (size_t i = 0, e = stackPosition_; i < e; ++i) {
+    thisSlots[i] = fromSlots[i];
+  }
+}
+
+bool MBasicBlock::inherit(TempAllocator& alloc, size_t stackDepth,
+                          MBasicBlock* maybePred, uint32_t popped) {
+  MOZ_ASSERT_IF(maybePred, maybePred->stackDepth() == stackDepth);
+
+  MOZ_ASSERT(stackDepth >= popped);
+  stackDepth -= popped;
+  stackPosition_ = stackDepth;
+
+  if (maybePred && kind_ != PENDING_LOOP_HEADER) {
+    copySlots(maybePred);
+  }
+
+  MOZ_ASSERT(info_.nslots() >= stackPosition_);
+  MOZ_ASSERT(!entryResumePoint_);
+
+  // Propagate the caller resume point from the inherited block.
+  callerResumePoint_ = maybePred ? maybePred->callerResumePoint() : nullptr;
+
+  // Create a resume point using our initial stack state.
+  entryResumePoint_ =
+      new (alloc) MResumePoint(this, pc(), ResumeMode::ResumeAt);
+  if (!entryResumePoint_->init(alloc)) {
+    return false;
+  }
+
+  if (maybePred) {
+    if (!predecessors_.append(maybePred)) {
+      return false;
+    }
+
+    if (kind_ == PENDING_LOOP_HEADER) {
+      for (size_t i = 0; i < stackDepth; i++) {
+        MPhi* phi = MPhi::New(alloc.fallible());
+        if (!phi) {
+          return false;
+        }
+        phi->addInlineInput(maybePred->getSlot(i));
+        addPhi(phi);
+        setSlot(i, phi);
+        entryResumePoint()->initOperand(i, phi);
+      }
+    } else {
+      for (size_t i = 0; i < stackDepth; i++) {
+        entryResumePoint()->initOperand(i, getSlot(i));
+      }
+    }
+  } else {
+    /*
+     * Don't leave the operands uninitialized for the caller, as it may not
+     * initialize them later on.
+     */
+    for (size_t i = 0; i < stackDepth; i++) {
+      entryResumePoint()->clearOperand(i);
+    }
+  }
+
+  return true;
+}
+
+void MBasicBlock::inheritSlots(MBasicBlock* parent) {
+  stackPosition_ = parent->stackPosition_;
+  copySlots(parent);
+}
+
+bool MBasicBlock::initEntrySlots(TempAllocator& alloc) {
+  // Remove the previous resume point.
+  discardResumePoint(entryResumePoint_);
+
+  // Create a resume point using our initial stack state.
+  entryResumePoint_ =
+      MResumePoint::New(alloc, this, pc(), ResumeMode::ResumeAt);
+  if (!entryResumePoint_) {
+    return false;
+  }
+  return true;
+}
+
+MDefinition* MBasicBlock::environmentChain() {
+  return getSlot(info().environmentChainSlot());
+}
+
+MDefinition* MBasicBlock::argumentsObject() {
+  return getSlot(info().argsObjSlot());
+}
+
+void MBasicBlock::setEnvironmentChain(MDefinition* scopeObj) {
+  setSlot(info().environmentChainSlot(), scopeObj);
+}
+
+void MBasicBlock::setArgumentsObject(MDefinition* argsObj) {
+  setSlot(info().argsObjSlot(), argsObj);
+}
+
+void MBasicBlock::pick(int32_t depth) {
+  // pick takes a value and moves it to the top.
+  // pick(-2):
+  //   A B C D E
+  //   A B D C E [ swapAt(-2) ]
+  //   A B D E C [ swapAt(-1) ]
+  for (; depth < 0; depth++) {
+    swapAt(depth);
+  }
+}
+
+void MBasicBlock::unpick(int32_t depth) {
+  // unpick takes the value on top of the stack and moves it under the depth-th
+  // element;
+  // unpick(-2):
+  //   A B C D E
+  //   A B C E D [ swapAt(-1) ]
+  //   A B E C D [ swapAt(-2) ]
+  for (int32_t n = -1; n >= depth; n--) {
+    swapAt(n);
+  }
+}
+
+void MBasicBlock::swapAt(int32_t depth) {
+  uint32_t lhsDepth = stackPosition_ + depth - 1;
+  uint32_t rhsDepth = stackPosition_ + depth;
+
+  MDefinition* temp = slots_[lhsDepth];
+  slots_[lhsDepth] = slots_[rhsDepth];
+  slots_[rhsDepth] = temp;
+}
+
+void MBasicBlock::discardLastIns() { discard(lastIns()); }
+
+MConstant* MBasicBlock::optimizedOutConstant(TempAllocator& alloc) {
+  // If the first instruction is a MConstant(MagicValue(JS_OPTIMIZED_OUT))
+  // then reuse it.
+  MInstruction* ins = *begin();
+  if (ins->type() == MIRType::MagicOptimizedOut) {
+    return ins->toConstant();
+  }
+
+  MConstant* constant = MConstant::New(alloc, MagicValue(JS_OPTIMIZED_OUT));
+  insertBefore(ins, constant);
+  return constant;
+}
+
+void MBasicBlock::moveBefore(MInstruction* at, MInstruction* ins) {
+  // Remove |ins| from the current block.
+  MOZ_ASSERT(ins->block() == this);
+  instructions_.remove(ins);
+
+  // Insert into new block, which may be distinct.
+  // Uses and operands are untouched.
+  ins->setInstructionBlock(at->block(), at->trackedSite());
+  at->block()->instructions_.insertBefore(at, ins);
+}
+
+MInstruction* MBasicBlock::safeInsertTop(MDefinition* ins, IgnoreTop ignore) {
+  MOZ_ASSERT(graph().osrBlock() != this,
+             "We are not supposed to add any instruction in OSR blocks.");
+
+  // Beta nodes and interrupt checks are required to be located at the
+  // beginnings of basic blocks, so we must insert new instructions after any
+  // such instructions.
+  MInstructionIterator insertIter =
+      !ins || ins->isPhi() ? begin() : begin(ins->toInstruction());
+  while (insertIter->isBeta() || insertIter->isInterruptCheck() ||
+         insertIter->isConstant() || insertIter->isParameter() ||
+         (!(ignore & IgnoreRecover) && insertIter->isRecoveredOnBailout())) {
+    insertIter++;
+  }
+
+  return *insertIter;
+}
+
+void MBasicBlock::discardResumePoint(
+    MResumePoint* rp, ReferencesType refType /* = RefType_Default */) {
+  if (refType & RefType_DiscardOperands) {
+    rp->releaseUses();
+  }
+  rp->setDiscarded();
+  removeResumePoint(rp);
+}
+
+void MBasicBlock::removeResumePoint(MResumePoint* rp) {
+#ifdef DEBUG
+  MResumePointIterator iter = resumePointsBegin();
+  while (*iter != rp) {
+    // We should reach it before reaching the end.
+    MOZ_ASSERT(iter != resumePointsEnd());
+    iter++;
+  }
+  resumePoints_.removeAt(iter);
+#endif
+}
+
+void MBasicBlock::prepareForDiscard(
+    MInstruction* ins, ReferencesType refType /* = RefType_Default */) {
+  // Only remove instructions from the same basic block.  This is needed for
+  // correctly removing the resume point if any.
+  MOZ_ASSERT(ins->block() == this);
+
+  MResumePoint* rp = ins->resumePoint();
+  if ((refType & RefType_DiscardResumePoint) && rp) {
+    discardResumePoint(rp, refType);
+  }
+
+  // We need to assert that instructions have no uses after removing the their
+  // resume points operands as they could be captured by their own resume
+  // point.
+  MOZ_ASSERT_IF(refType & RefType_AssertNoUses, !ins->hasUses());
+
+  const uint32_t InstructionOperands =
+      RefType_DiscardOperands | RefType_DiscardInstruction;
+  if ((refType & InstructionOperands) == InstructionOperands) {
+    for (size_t i = 0, e = ins->numOperands(); i < e; i++) {
+      ins->releaseOperand(i);
+    }
+  }
+
+  ins->setDiscarded();
+}
+
+void MBasicBlock::discard(MInstruction* ins) {
+  prepareForDiscard(ins);
+  instructions_.remove(ins);
+}
+
+void MBasicBlock::discardIgnoreOperands(MInstruction* ins) {
+#ifdef DEBUG
+  for (size_t i = 0, e = ins->numOperands(); i < e; i++) {
+    MOZ_ASSERT(!ins->hasOperand(i));
+  }
+#endif
+
+  prepareForDiscard(ins, RefType_IgnoreOperands);
+  instructions_.remove(ins);
+}
+
+void MBasicBlock::discardAllInstructions() {
+  MInstructionIterator iter = begin();
+  discardAllInstructionsStartingAt(iter);
+}
+
+void MBasicBlock::discardAllInstructionsStartingAt(MInstructionIterator iter) {
+  while (iter != end()) {
+    // Discard operands and resume point operands and flag the instruction
+    // as discarded.  Also we do not assert that we have no uses as blocks
+    // might be removed in reverse post order.
+    MInstruction* ins = *iter++;
+    prepareForDiscard(ins, RefType_DefaultNoAssert);
+    instructions_.remove(ins);
+  }
+}
+
+void MBasicBlock::discardAllPhis() {
+  for (MPhiIterator iter = phisBegin(); iter != phisEnd(); iter++) {
+    iter->removeAllOperands();
+  }
+
+  for (MBasicBlock** pred = predecessors_.begin(); pred != predecessors_.end();
+       pred++) {
+    (*pred)->clearSuccessorWithPhis();
+  }
+
+  phis_.clear();
+}
+
+void MBasicBlock::discardAllResumePoints(bool discardEntry) {
+  if (outerResumePoint_) {
+    clearOuterResumePoint();
+  }
+
+  if (discardEntry && entryResumePoint_) {
+    clearEntryResumePoint();
+  }
+
+#ifdef DEBUG
+  if (!entryResumePoint()) {
+    MOZ_ASSERT(resumePointsEmpty());
+  } else {
+    MResumePointIterator iter(resumePointsBegin());
+    MOZ_ASSERT(iter != resumePointsEnd());
+    iter++;
+    MOZ_ASSERT(iter == resumePointsEnd());
+  }
+#endif
+}
+
+void MBasicBlock::clear() {
+  discardAllInstructions();
+  discardAllResumePoints();
+  discardAllPhis();
+}
+
+void MBasicBlock::insertBefore(MInstruction* at, MInstruction* ins) {
+  MOZ_ASSERT(at->block() == this);
+  ins->setInstructionBlock(this, at->trackedSite());
+  graph().allocDefinitionId(ins);
+  instructions_.insertBefore(at, ins);
+}
+
+void MBasicBlock::insertAfter(MInstruction* at, MInstruction* ins) {
+  MOZ_ASSERT(at->block() == this);
+  ins->setInstructionBlock(this, at->trackedSite());
+  graph().allocDefinitionId(ins);
+  instructions_.insertAfter(at, ins);
+}
+
+void MBasicBlock::insertAtEnd(MInstruction* ins) {
+  if (hasLastIns()) {
+    insertBefore(lastIns(), ins);
+  } else {
+    add(ins);
+  }
+}
+
+void MBasicBlock::addPhi(MPhi* phi) {
+  phis_.pushBack(phi);
+  phi->setPhiBlock(this);
+  graph().allocDefinitionId(phi);
+}
+
+void MBasicBlock::discardPhi(MPhi* phi) {
+  MOZ_ASSERT(!phis_.empty());
+
+  phi->removeAllOperands();
+  phi->setDiscarded();
+
+  phis_.remove(phi);
+
+  if (phis_.empty()) {
+    for (MBasicBlock* pred : predecessors_) {
+      pred->clearSuccessorWithPhis();
+    }
+  }
+}
+
+MResumePoint* MBasicBlock::activeResumePoint(MInstruction* ins) {
+  for (MInstructionReverseIterator iter = rbegin(ins); iter != rend(); iter++) {
+    if (iter->resumePoint() && *iter != ins) {
+      return iter->resumePoint();
+    }
+  }
+
+  // If none, take the entry resume point.
+  return entryResumePoint();
+}
+
+void MBasicBlock::flagOperandsOfPrunedBranches(MInstruction* ins) {
+  MResumePoint* rp = activeResumePoint(ins);
+
+  // The only blocks which do not have any entryResumePoint in Ion, are the
+  // SplitEdge blocks.  SplitEdge blocks only have a Goto instruction before
+  // Range Analysis phase.  In adjustInputs, we are manipulating instructions
+  // which have a TypePolicy.  So, as a Goto has no operand and no type
+  // policy, the entry resume point should exist.
+  MOZ_ASSERT(rp);
+
+  // Flag all operands as being potentially used.
+  while (rp) {
+    for (size_t i = 0, end = rp->numOperands(); i < end; i++) {
+      rp->getOperand(i)->setImplicitlyUsedUnchecked();
+    }
+    rp = rp->caller();
+  }
+}
+
+bool MBasicBlock::addPredecessor(TempAllocator& alloc, MBasicBlock* pred) {
+  return addPredecessorPopN(alloc, pred, 0);
+}
+
+bool MBasicBlock::addPredecessorPopN(TempAllocator& alloc, MBasicBlock* pred,
+                                     uint32_t popped) {
+  MOZ_ASSERT(pred);
+  MOZ_ASSERT(predecessors_.length() > 0);
+
+  // Predecessors must be finished, and at the correct stack depth.
+  MOZ_ASSERT(pred->hasLastIns());
+  MOZ_ASSERT(pred->stackPosition_ == stackPosition_ + popped);
+
+  for (uint32_t i = 0, e = stackPosition_; i < e; ++i) {
+    MDefinition* mine = getSlot(i);
+    MDefinition* other = pred->getSlot(i);
+
+    if (mine != other) {
+      MIRType phiType = mine->type();
+      if (phiType != other->type()) {
+        phiType = MIRType::Value;
+      }
+
+      // If the current instruction is a phi, and it was created in this
+      // basic block, then we have already placed this phi and should
+      // instead append to its operands.
+      if (mine->isPhi() && mine->block() == this) {
+        MOZ_ASSERT(predecessors_.length());
+        MOZ_ASSERT(!mine->hasDefUses(),
+                   "should only change type of newly created phis");
+        mine->setResultType(phiType);
+        if (!mine->toPhi()->addInputSlow(other)) {
+          return false;
+        }
+      } else {
+        // Otherwise, create a new phi node.
+        MPhi* phi = MPhi::New(alloc.fallible(), phiType);
+        if (!phi) {
+          return false;
+        }
+        addPhi(phi);
+
+        // Prime the phi for each predecessor, so input(x) comes from
+        // predecessor(x).
+        if (!phi->reserveLength(predecessors_.length() + 1)) {
+          return false;
+        }
+
+        for (size_t j = 0, numPreds = predecessors_.length(); j < numPreds;
+             ++j) {
+          MOZ_ASSERT(predecessors_[j]->getSlot(i) == mine);
+          phi->addInput(mine);
+        }
+        phi->addInput(other);
+
+        setSlot(i, phi);
+        if (entryResumePoint()) {
+          entryResumePoint()->replaceOperand(i, phi);
+        }
+      }
+    }
+  }
+
+  return predecessors_.append(pred);
+}
+
+bool MBasicBlock::addPredecessorSameInputsAs(MBasicBlock* pred,
+                                             MBasicBlock* existingPred) {
+  MOZ_ASSERT(pred);
+  MOZ_ASSERT(predecessors_.length() > 0);
+
+  // Predecessors must be finished, and at the correct stack depth.
+  MOZ_ASSERT(pred->hasLastIns());
+  MOZ_ASSERT(!pred->successorWithPhis());
+
+  if (!phisEmpty()) {
+    size_t existingPosition = indexForPredecessor(existingPred);
+    for (MPhiIterator iter = phisBegin(); iter != phisEnd(); iter++) {
+      if (!iter->addInputSlow(iter->getOperand(existingPosition))) {
+        return false;
+      }
+    }
+  }
+
+  if (!predecessors_.append(pred)) {
+    return false;
+  }
+  return true;
+}
+
+bool MBasicBlock::addPredecessorWithoutPhis(MBasicBlock* pred) {
+  // Predecessors must be finished.
+  MOZ_ASSERT(pred && pred->hasLastIns());
+  return predecessors_.append(pred);
+}
+
+bool MBasicBlock::addImmediatelyDominatedBlock(MBasicBlock* child) {
+  return immediatelyDominated_.append(child);
+}
+
+void MBasicBlock::removeImmediatelyDominatedBlock(MBasicBlock* child) {
+  for (size_t i = 0;; ++i) {
+    MOZ_ASSERT(i < immediatelyDominated_.length(),
+               "Dominated block to remove not present");
+    if (immediatelyDominated_[i] == child) {
+      immediatelyDominated_[i] = immediatelyDominated_.back();
+      immediatelyDominated_.popBack();
+      return;
+    }
+  }
+}
+
+bool MBasicBlock::setBackedge(MBasicBlock* pred) {
+  // Predecessors must be finished, and at the correct stack depth.
+  MOZ_ASSERT(hasLastIns());
+  MOZ_ASSERT(pred->hasLastIns());
+  MOZ_ASSERT(pred->stackDepth() == entryResumePoint()->stackDepth());
+
+  // We must be a pending loop header
+  MOZ_ASSERT(kind_ == PENDING_LOOP_HEADER);
+
+  // Add exit definitions to each corresponding phi at the entry.
+  if (!inheritPhisFromBackedge(pred)) {
+    return false;
+  }
+
+  // We are now a loop header proper
+  kind_ = LOOP_HEADER;
+
+  return predecessors_.append(pred);
+}
+
+bool MBasicBlock::setBackedgeWasm(MBasicBlock* pred, size_t paramCount) {
+  // Predecessors must be finished, and at the correct stack depth.
+  MOZ_ASSERT(hasLastIns());
+  MOZ_ASSERT(pred->hasLastIns());
+  MOZ_ASSERT(stackDepth() + paramCount == pred->stackDepth());
+
+  // We must be a pending loop header
+  MOZ_ASSERT(kind_ == PENDING_LOOP_HEADER);
+
+  // Add exit definitions to each corresponding phi at the entry.
+  // Note: Phis are inserted in the same order as the slots. (see
+  // MBasicBlock::New)
+  size_t slot = 0;
+  for (MPhiIterator phi = phisBegin(); phi != phisEnd(); phi++, slot++) {
+    MPhi* entryDef = *phi;
+    MDefinition* exitDef = pred->getSlot(slot);
+
+    // Assert that we already placed phis for each slot.
+    MOZ_ASSERT(entryDef->block() == this);
+
+    // Assert that the phi already has the correct type.
+    MOZ_ASSERT(entryDef->type() == exitDef->type());
+    MOZ_ASSERT(entryDef->type() != MIRType::Value);
+
+    if (entryDef == exitDef) {
+      // If the exit def is the same as the entry def, make a redundant
+      // phi. Since loop headers have exactly two incoming edges, we
+      // know that that's just the first input.
+      //
+      // Note that we eliminate later rather than now, to avoid any
+      // weirdness around pending continue edges which might still hold
+      // onto phis.
+      exitDef = entryDef->getOperand(0);
+    }
+
+    // Phis always have room for 2 operands, so this can't fail.
+    MOZ_ASSERT(phi->numOperands() == 1);
+    entryDef->addInlineInput(exitDef);
+
+    // Two cases here: phis that correspond to locals, and phis that correspond
+    // to loop parameters.  Only phis for locals go in slots.
+    if (slot < stackDepth()) {
+      setSlot(slot, entryDef);
+    }
+  }
+
+  // We are now a loop header proper
+  kind_ = LOOP_HEADER;
+
+  return predecessors_.append(pred);
+}
+
+void MBasicBlock::clearLoopHeader() {
+  MOZ_ASSERT(isLoopHeader());
+  kind_ = NORMAL;
+}
+
+void MBasicBlock::setLoopHeader(MBasicBlock* newBackedge) {
+  MOZ_ASSERT(!isLoopHeader());
+  kind_ = LOOP_HEADER;
+
+  size_t numPreds = numPredecessors();
+  MOZ_ASSERT(numPreds != 0);
+
+  size_t lastIndex = numPreds - 1;
+  size_t oldIndex = 0;
+  for (;; ++oldIndex) {
+    MOZ_ASSERT(oldIndex < numPreds);
+    MBasicBlock* pred = getPredecessor(oldIndex);
+    if (pred == newBackedge) {
+      break;
+    }
+  }
+
+  // Set the loop backedge to be the last element in predecessors_.
+  std::swap(predecessors_[oldIndex], predecessors_[lastIndex]);
+
+  // If we have phis, reorder their operands accordingly.
+  if (!phisEmpty()) {
+    getPredecessor(oldIndex)->setSuccessorWithPhis(this, oldIndex);
+    getPredecessor(lastIndex)->setSuccessorWithPhis(this, lastIndex);
+    for (MPhiIterator iter(phisBegin()), end(phisEnd()); iter != end; ++iter) {
+      MPhi* phi = *iter;
+      MDefinition* last = phi->getOperand(oldIndex);
+      MDefinition* old = phi->getOperand(lastIndex);
+      phi->replaceOperand(oldIndex, old);
+      phi->replaceOperand(lastIndex, last);
+    }
+  }
+
+  MOZ_ASSERT(newBackedge->loopHeaderOfBackedge() == this);
+  MOZ_ASSERT(backedge() == newBackedge);
+}
+
+size_t MBasicBlock::getSuccessorIndex(MBasicBlock* block) const {
+  MOZ_ASSERT(lastIns());
+  for (size_t i = 0; i < numSuccessors(); i++) {
+    if (getSuccessor(i) == block) {
+      return i;
+    }
+  }
+  MOZ_CRASH("Invalid successor");
+}
+
+size_t MBasicBlock::getPredecessorIndex(MBasicBlock* block) const {
+  for (size_t i = 0, e = numPredecessors(); i < e; ++i) {
+    if (getPredecessor(i) == block) {
+      return i;
+    }
+  }
+  MOZ_CRASH("Invalid predecessor");
+}
+
+void MBasicBlock::replaceSuccessor(size_t pos, MBasicBlock* split) {
+  MOZ_ASSERT(lastIns());
+
+  // Note, during split-critical-edges, successors-with-phis is not yet set.
+  // During PAA, this case is handled before we enter.
+  MOZ_ASSERT_IF(successorWithPhis_, successorWithPhis_ != getSuccessor(pos));
+
+  lastIns()->replaceSuccessor(pos, split);
+}
+
+void MBasicBlock::replacePredecessor(MBasicBlock* old, MBasicBlock* split) {
+  for (size_t i = 0; i < numPredecessors(); i++) {
+    if (getPredecessor(i) == old) {
+      predecessors_[i] = split;
+
+#ifdef DEBUG
+      // The same block should not appear twice in the predecessor list.
+      for (size_t j = i; j < numPredecessors(); j++) {
+        MOZ_ASSERT(predecessors_[j] != old);
+      }
+#endif
+
+      return;
+    }
+  }
+
+  MOZ_CRASH("predecessor was not found");
+}
+
+void MBasicBlock::clearDominatorInfo() {
+  setImmediateDominator(nullptr);
+  immediatelyDominated_.clear();
+  numDominated_ = 0;
+}
+
+void MBasicBlock::removePredecessorWithoutPhiOperands(MBasicBlock* pred,
+                                                      size_t predIndex) {
+  // If we're removing the last backedge, this is no longer a loop.
+  if (isLoopHeader() && hasUniqueBackedge() && backedge() == pred) {
+    clearLoopHeader();
+  }
+
+  // Adjust phis.  Note that this can leave redundant phis behind.
+  // Don't adjust successorWithPhis() if we haven't constructed this
+  // information yet.
+  if (pred->successorWithPhis()) {
+    MOZ_ASSERT(pred->positionInPhiSuccessor() == predIndex);
+    pred->clearSuccessorWithPhis();
+    for (size_t j = predIndex + 1; j < numPredecessors(); j++) {
+      getPredecessor(j)->setSuccessorWithPhis(this, j - 1);
+    }
+  }
+
+  // Remove from pred list.
+  predecessors_.erase(predecessors_.begin() + predIndex);
+}
+
+void MBasicBlock::removePredecessor(MBasicBlock* pred) {
+  size_t predIndex = getPredecessorIndex(pred);
+
+  // Remove the phi operands.
+  for (MPhiIterator iter(phisBegin()), end(phisEnd()); iter != end; ++iter) {
+    iter->removeOperand(predIndex);
+  }
+
+  // Now we can call the underlying function, which expects that phi
+  // operands have been removed.
+  removePredecessorWithoutPhiOperands(pred, predIndex);
+}
+
+bool MBasicBlock::inheritPhisFromBackedge(MBasicBlock* backedge) {
+  // We must be a pending loop header
+  MOZ_ASSERT(kind_ == PENDING_LOOP_HEADER);
+
+  size_t stackDepth = entryResumePoint()->stackDepth();
+  for (size_t slot = 0; slot < stackDepth; slot++) {
+    // Get the value stack-slot of the back edge.
+    MDefinition* exitDef = backedge->getSlot(slot);
+
+    // Get the value of the loop header.
+    MDefinition* loopDef = entryResumePoint()->getOperand(slot);
+    if (loopDef->block() != this) {
+      // If we are finishing a pending loop header, then we need to ensure
+      // that all operands are phis. This is usualy the case, except for
+      // object/arrays build with generators, in which case we share the
+      // same allocations across all blocks.
+      MOZ_ASSERT(loopDef->block()->id() < id());
+      MOZ_ASSERT(loopDef == exitDef);
+      continue;
+    }
+
+    // Phis are allocated by NewPendingLoopHeader.
+    MPhi* entryDef = loopDef->toPhi();
+    MOZ_ASSERT(entryDef->block() == this);
+
+    if (entryDef == exitDef) {
+      // If the exit def is the same as the entry def, make a redundant
+      // phi. Since loop headers have exactly two incoming edges, we
+      // know that that's just the first input.
+      //
+      // Note that we eliminate later rather than now, to avoid any
+      // weirdness around pending continue edges which might still hold
+      // onto phis.
+      exitDef = entryDef->getOperand(0);
+    }
+
+    if (!entryDef->addInputSlow(exitDef)) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+MTest* MBasicBlock::immediateDominatorBranch(BranchDirection* pdirection) {
+  *pdirection = FALSE_BRANCH;
+
+  if (numPredecessors() != 1) {
+    return nullptr;
+  }
+
+  MBasicBlock* dom = immediateDominator();
+  if (dom != getPredecessor(0)) {
+    return nullptr;
+  }
+
+  // Look for a trailing MTest branching to this block.
+  MInstruction* ins = dom->lastIns();
+  if (ins->isTest()) {
+    MTest* test = ins->toTest();
+
+    MOZ_ASSERT(test->ifTrue() == this || test->ifFalse() == this);
+    if (test->ifTrue() == this && test->ifFalse() == this) {
+      return nullptr;
+    }
+
+    *pdirection = (test->ifTrue() == this) ? TRUE_BRANCH : FALSE_BRANCH;
+    return test;
+  }
+
+  return nullptr;
+}
+
+void MBasicBlock::dumpStack(GenericPrinter& out) {
+#ifdef DEBUG
+  out.printf(" %-3s %-16s %-6s %-10s\n", "#", "name", "copyOf", "first/next");
+  out.printf("-------------------------------------------\n");
+  for (uint32_t i = 0; i < stackPosition_; i++) {
+    out.printf(" %-3u", i);
+    out.printf(" %-16p\n", (void*)slots_[i]);
+  }
+#endif
+}
+
+void MBasicBlock::dumpStack() {
+  Fprinter out(stderr);
+  dumpStack(out);
+  out.finish();
+}
+
+void MIRGraph::dump(GenericPrinter& out) {
+#ifdef JS_JITSPEW
+  for (MBasicBlockIterator iter(begin()); iter != end(); iter++) {
+    iter->dump(out);
+    out.printf("\n");
+  }
+#endif
+}
+
+void MIRGraph::dump() {
+  Fprinter out(stderr);
+  dump(out);
+  out.finish();
+}
+
+void MBasicBlock::dump(GenericPrinter& out) {
+#ifdef JS_JITSPEW
+  out.printf("block%u:%s%s%s\n", id(), isLoopHeader() ? " (loop header)" : "",
+             unreachable() ? " (unreachable)" : "",
+             isMarked() ? " (marked)" : "");
+  if (MResumePoint* resume = entryResumePoint()) {
+    resume->dump(out);
+  }
+  for (MPhiIterator iter(phisBegin()); iter != phisEnd(); iter++) {
+    iter->dump(out);
+  }
+  for (MInstructionIterator iter(begin()); iter != end(); iter++) {
+    iter->dump(out);
+  }
+#endif
+}
+
+void MBasicBlock::dump() {
+  Fprinter out(stderr);
+  dump(out);
+  out.finish();
+}