1 files changed, 714 insertions, 0 deletions
diff --git a/js/src/jit/JitScript.cpp b/js/src/jit/JitScript.cpp
new file mode 100644
index 0000000000..829665adf1
--- /dev/null
+++ b/js/src/jit/JitScript.cpp
@@ -0,0 +1,714 @@
+/* -*- 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/JitScript-inl.h"
+
+#include "mozilla/BinarySearch.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/IntegerPrintfMacros.h"
+#include "mozilla/ScopeExit.h"
+
+#include <utility>
+
+#include "jit/BaselineIC.h"
+#include "jit/BytecodeAnalysis.h"
+#include "jit/IonScript.h"
+#include "jit/JitFrames.h"
+#include "jit/ScriptFromCalleeToken.h"
+#include "util/Memory.h"
+#include "vm/BytecodeIterator.h"
+#include "vm/BytecodeLocation.h"
+#include "vm/BytecodeUtil.h"
+#include "vm/FrameIter.h"  // js::OnlyJSJitFrameIter
+#include "vm/JSScript.h"
+#include "vm/Stack.h"
+#include "wasm/WasmInstance.h"
+
+#include "gc/FreeOp-inl.h"
+#include "jit/JSJitFrameIter-inl.h"
+#include "vm/BytecodeIterator-inl.h"
+#include "vm/BytecodeLocation-inl.h"
+#include "vm/JSScript-inl.h"
+
+using namespace js;
+using namespace js::jit;
+
+using mozilla::CheckedInt;
+
+JitScript::JitScript(JSScript* script, Offset endOffset,
+                     const char* profileString)
+    : profileString_(profileString),
+      endOffset_(endOffset),
+      icScript_(script->getWarmUpCount(), endOffset - offsetOfICScript(),
+                /*depth=*/0) {
+  // Ensure the baselineScript_ and ionScript_ fields match the BaselineDisabled
+  // and IonDisabled script flags.
+  if (!script->canBaselineCompile()) {
+    setBaselineScriptImpl(script, BaselineDisabledScriptPtr);
+  }
+  if (!script->canIonCompile()) {
+    setIonScriptImpl(script, IonDisabledScriptPtr);
+  }
+}
+
+bool JSScript::createJitScript(JSContext* cx) {
+  MOZ_ASSERT(!hasJitScript());
+  cx->check(this);
+
+  // Scripts with a JitScript can run in the Baseline Interpreter. Make sure
+  // we don't create a JitScript for scripts we shouldn't Baseline interpret.
+  MOZ_ASSERT_IF(IsBaselineInterpreterEnabled(),
+                CanBaselineInterpretScript(this));
+
+  gc::AutoSuppressGC suppressGC(cx);
+
+  // Run the arguments-analysis if needed. Both the Baseline Interpreter and
+  // Compiler rely on this.
+  if (!ensureHasAnalyzedArgsUsage(cx)) {
+    return false;
+  }
+
+  // If ensureHasAnalyzedArgsUsage allocated the JitScript we're done.
+  if (hasJitScript()) {
+    return true;
+  }
+
+  // Store the profile string in the JitScript if the profiler is enabled.
+  const char* profileString = nullptr;
+  if (cx->runtime()->geckoProfiler().enabled()) {
+    profileString = cx->runtime()->geckoProfiler().profileString(cx, this);
+    if (!profileString) {
+      return false;
+    }
+  }
+
+  static_assert(sizeof(JitScript) % sizeof(uintptr_t) == 0,
+                "Trailing arrays must be aligned properly");
+  static_assert(sizeof(ICEntry) % sizeof(uintptr_t) == 0,
+                "Trailing arrays must be aligned properly");
+
+  static_assert(
+      sizeof(JitScript) == offsetof(JitScript, icScript_) + sizeof(ICScript),
+      "icScript_ must be the last field");
+
+  // Calculate allocation size.
+  CheckedInt<uint32_t> allocSize = sizeof(JitScript);
+  allocSize += CheckedInt<uint32_t>(numICEntries()) * sizeof(ICEntry);
+  if (!allocSize.isValid()) {
+    ReportAllocationOverflow(cx);
+    return false;
+  }
+
+  void* raw = cx->pod_malloc<uint8_t>(allocSize.value());
+  MOZ_ASSERT(uintptr_t(raw) % alignof(JitScript) == 0);
+  if (!raw) {
+    return false;
+  }
+
+  UniquePtr<JitScript> jitScript(
+      new (raw) JitScript(this, allocSize.value(), profileString));
+
+  // Sanity check the length computation.
+  MOZ_ASSERT(jitScript->numICEntries() == numICEntries());
+
+  // We need to call prepareForDestruction on JitScript before we |delete| it.
+  auto prepareForDestruction = mozilla::MakeScopeExit(
+      [&] { jitScript->prepareForDestruction(cx->zone()); });
+
+  if (!jitScript->icScript()->initICEntries(cx, this)) {
+    return false;
+  }
+
+  prepareForDestruction.release();
+  warmUpData_.initJitScript(jitScript.release());
+  AddCellMemory(this, allocSize.value(), MemoryUse::JitScript);
+
+  // We have a JitScript so we can set the script's jitCodeRaw pointer to the
+  // Baseline Interpreter code.
+  updateJitCodeRaw(cx->runtime());
+
+  return true;
+}
+
+void JSScript::maybeReleaseJitScript(JSFreeOp* fop) {
+  MOZ_ASSERT(hasJitScript());
+
+  if (zone()->jitZone()->keepJitScripts() || jitScript()->hasBaselineScript() ||
+      jitScript()->active()) {
+    return;
+  }
+
+  releaseJitScript(fop);
+}
+
+void JSScript::releaseJitScript(JSFreeOp* fop) {
+  MOZ_ASSERT(hasJitScript());
+  MOZ_ASSERT(!hasBaselineScript());
+  MOZ_ASSERT(!hasIonScript());
+
+  fop->removeCellMemory(this, jitScript()->allocBytes(), MemoryUse::JitScript);
+
+  JitScript::Destroy(zone(), jitScript());
+  warmUpData_.clearJitScript();
+  updateJitCodeRaw(fop->runtime());
+}
+
+void JSScript::releaseJitScriptOnFinalize(JSFreeOp* fop) {
+  MOZ_ASSERT(hasJitScript());
+
+  if (hasIonScript()) {
+    IonScript* ion = jitScript()->clearIonScript(fop, this);
+    jit::IonScript::Destroy(fop, ion);
+  }
+
+  if (hasBaselineScript()) {
+    BaselineScript* baseline = jitScript()->clearBaselineScript(fop, this);
+    jit::BaselineScript::Destroy(fop, baseline);
+  }
+
+  releaseJitScript(fop);
+}
+
+void JitScript::CachedIonData::trace(JSTracer* trc) {
+  TraceNullableEdge(trc, &templateEnv, "jitscript-iondata-template-env");
+}
+
+void JitScript::trace(JSTracer* trc) {
+  icScript_.trace(trc);
+
+  if (hasBaselineScript()) {
+    baselineScript()->trace(trc);
+  }
+
+  if (hasIonScript()) {
+    ionScript()->trace(trc);
+  }
+
+  if (hasCachedIonData()) {
+    cachedIonData().trace(trc);
+  }
+
+  if (hasInliningRoot()) {
+    inliningRoot()->trace(trc);
+  }
+}
+
+void ICScript::trace(JSTracer* trc) {
+  // Mark all IC stub codes hanging off the IC stub entries.
+  for (size_t i = 0; i < numICEntries(); i++) {
+    ICEntry& ent = icEntry(i);
+    ent.trace(trc);
+  }
+}
+
+bool ICScript::addInlinedChild(JSContext* cx, UniquePtr<ICScript> child,
+                               uint32_t pcOffset) {
+  MOZ_ASSERT(!hasInlinedChild(pcOffset));
+
+  if (!inlinedChildren_) {
+    inlinedChildren_ = cx->make_unique<Vector<CallSite>>(cx);
+    if (!inlinedChildren_) {
+      return false;
+    }
+  }
+
+  // First reserve space in inlinedChildren_ to ensure that if the ICScript is
+  // added to the inlining root, it can also be added to inlinedChildren_.
+  CallSite callsite(child.get(), pcOffset);
+  if (!inlinedChildren_->reserve(inlinedChildren_->length() + 1)) {
+    return false;
+  }
+  if (!inliningRoot()->addInlinedScript(std::move(child))) {
+    return false;
+  }
+  inlinedChildren_->infallibleAppend(callsite);
+  return true;
+}
+
+ICScript* ICScript::findInlinedChild(uint32_t pcOffset) {
+  for (auto& callsite : *inlinedChildren_) {
+    if (callsite.pcOffset_ == pcOffset) {
+      return callsite.callee_;
+    }
+  }
+  MOZ_CRASH("Inlined child expected at pcOffset");
+}
+
+void ICScript::removeInlinedChild(uint32_t pcOffset) {
+  MOZ_ASSERT(inliningRoot());
+  inlinedChildren_->eraseIf([pcOffset](const CallSite& callsite) -> bool {
+    return callsite.pcOffset_ == pcOffset;
+  });
+}
+
+bool ICScript::hasInlinedChild(uint32_t pcOffset) {
+  if (!inlinedChildren_) {
+    return false;
+  }
+  for (auto& callsite : *inlinedChildren_) {
+    if (callsite.pcOffset_ == pcOffset) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void JitScript::resetWarmUpCount(uint32_t count) {
+  icScript_.resetWarmUpCount(count);
+  if (hasInliningRoot()) {
+    inliningRoot()->resetWarmUpCounts(count);
+  }
+}
+
+void JitScript::ensureProfileString(JSContext* cx, JSScript* script) {
+  MOZ_ASSERT(cx->runtime()->geckoProfiler().enabled());
+
+  if (profileString_) {
+    return;
+  }
+
+  AutoEnterOOMUnsafeRegion oomUnsafe;
+  profileString_ = cx->runtime()->geckoProfiler().profileString(cx, script);
+  if (!profileString_) {
+    oomUnsafe.crash("Failed to allocate profile string");
+  }
+}
+
+/* static */
+void JitScript::Destroy(Zone* zone, JitScript* script) {
+  script->prepareForDestruction(zone);
+
+  js_delete(script);
+}
+
+struct ICEntries {
+  ICScript* const icScript_;
+
+  explicit ICEntries(ICScript* icScript) : icScript_(icScript) {}
+
+  size_t numEntries() const { return icScript_->numICEntries(); }
+  ICEntry& operator[](size_t index) const { return icScript_->icEntry(index); }
+};
+
+static bool ComputeBinarySearchMid(ICEntries entries, uint32_t pcOffset,
+                                   size_t* loc) {
+  return mozilla::BinarySearchIf(
+      entries, 0, entries.numEntries(),
+      [pcOffset](const ICEntry& entry) {
+        uint32_t entryOffset = entry.pcOffset();
+        if (pcOffset < entryOffset) {
+          return -1;
+        }
+        if (entryOffset < pcOffset) {
+          return 1;
+        }
+        return 0;
+      },
+      loc);
+}
+
+ICEntry* ICScript::maybeICEntryFromPCOffset(uint32_t pcOffset) {
+  // This method ignores prologue IC entries. There can be at most one
+  // non-prologue IC per bytecode op.
+
+  size_t mid;
+  if (!ComputeBinarySearchMid(ICEntries(this), pcOffset, &mid)) {
+    return nullptr;
+  }
+
+  MOZ_ASSERT(mid < numICEntries());
+
+  ICEntry& entry = icEntry(mid);
+  MOZ_ASSERT(entry.pcOffset() == pcOffset);
+  return &entry;
+}
+
+ICEntry& ICScript::icEntryFromPCOffset(uint32_t pcOffset) {
+  ICEntry* entry = maybeICEntryFromPCOffset(pcOffset);
+  MOZ_RELEASE_ASSERT(entry);
+  return *entry;
+}
+
+ICEntry* ICScript::maybeICEntryFromPCOffset(uint32_t pcOffset,
+                                            ICEntry* prevLookedUpEntry) {
+  // Do a linear forward search from the last queried PC offset, or fallback to
+  // a binary search if the last offset is too far away.
+  if (prevLookedUpEntry && pcOffset >= prevLookedUpEntry->pcOffset() &&
+      (pcOffset - prevLookedUpEntry->pcOffset()) <= 10) {
+    ICEntry* firstEntry = &icEntry(0);
+    ICEntry* lastEntry = &icEntry(numICEntries() - 1);
+    ICEntry* curEntry = prevLookedUpEntry;
+    while (curEntry >= firstEntry && curEntry <= lastEntry) {
+      if (curEntry->pcOffset() == pcOffset) {
+        return curEntry;
+      }
+      curEntry++;
+    }
+    return nullptr;
+  }
+
+  return maybeICEntryFromPCOffset(pcOffset);
+}
+
+ICEntry& ICScript::icEntryFromPCOffset(uint32_t pcOffset,
+                                       ICEntry* prevLookedUpEntry) {
+  ICEntry* entry = maybeICEntryFromPCOffset(pcOffset, prevLookedUpEntry);
+  MOZ_RELEASE_ASSERT(entry);
+  return *entry;
+}
+
+ICEntry* ICScript::interpreterICEntryFromPCOffset(uint32_t pcOffset) {
+  // We have to return the entry to store in BaselineFrame::interpreterICEntry
+  // when resuming in the Baseline Interpreter at pcOffset. The bytecode op at
+  // pcOffset does not necessarily have an ICEntry, so we want to return the
+  // first ICEntry for which the following is true:
+  //
+  //    entry.pcOffset() >= pcOffset
+  //
+  // Fortunately, ComputeBinarySearchMid returns exactly this entry.
+
+  size_t mid;
+  ComputeBinarySearchMid(ICEntries(this), pcOffset, &mid);
+
+  if (mid < numICEntries()) {
+    ICEntry& entry = icEntry(mid);
+    MOZ_ASSERT(entry.pcOffset() >= pcOffset);
+    return &entry;
+  }
+
+  // Resuming at a pc after the last ICEntry. Just return nullptr:
+  // BaselineFrame::interpreterICEntry will never be used in this case.
+  return nullptr;
+}
+
+void JitScript::purgeOptimizedStubs(JSScript* script) {
+  MOZ_ASSERT(script->jitScript() == this);
+
+  Zone* zone = script->zone();
+  if (IsAboutToBeFinalizedUnbarriered(&script)) {
+    // We're sweeping and the script is dead. Don't purge optimized stubs
+    // because (1) accessing CacheIRStubInfo pointers in ICStubs is invalid
+    // because we may have swept them already when we started (incremental)
+    // sweeping and (2) it's unnecessary because this script will be finalized
+    // soon anyway.
+    return;
+  }
+
+  JitSpew(JitSpew_BaselineIC, "Purging optimized stubs");
+
+  icScript()->purgeOptimizedStubs(zone);
+  if (hasInliningRoot()) {
+    inliningRoot()->purgeOptimizedStubs(zone);
+  }
+#ifdef DEBUG
+  failedICHash_.reset();
+#endif
+}
+
+void ICScript::purgeOptimizedStubs(Zone* zone) {
+  for (size_t i = 0; i < numICEntries(); i++) {
+    ICEntry& entry = icEntry(i);
+    ICStub* lastStub = entry.firstStub();
+    while (!lastStub->isFallback()) {
+      lastStub = lastStub->toCacheIRStub()->next();
+    }
+
+    // Unlink all stubs allocated in the optimized space.
+    ICStub* stub = entry.firstStub();
+    ICCacheIRStub* prev = nullptr;
+
+    while (stub != lastStub) {
+      if (!stub->toCacheIRStub()->allocatedInFallbackSpace()) {
+        lastStub->toFallbackStub()->unlinkStub(zone, prev,
+                                               stub->toCacheIRStub());
+        stub = stub->toCacheIRStub()->next();
+        continue;
+      }
+
+      prev = stub->toCacheIRStub();
+      stub = stub->toCacheIRStub()->next();
+    }
+  }
+
+#ifdef DEBUG
+  // All remaining stubs must be allocated in the fallback space.
+  for (size_t i = 0; i < numICEntries(); i++) {
+    ICEntry& entry = icEntry(i);
+    ICStub* stub = entry.firstStub();
+    while (!stub->isFallback()) {
+      MOZ_ASSERT(stub->toCacheIRStub()->allocatedInFallbackSpace());
+      stub = stub->toCacheIRStub()->next();
+    }
+  }
+#endif
+}
+
+JitScript::CachedIonData::CachedIonData(EnvironmentObject* templateEnv,
+                                        IonBytecodeInfo bytecodeInfo)
+    : templateEnv(templateEnv), bytecodeInfo(bytecodeInfo) {}
+
+bool JitScript::ensureHasCachedIonData(JSContext* cx, HandleScript script) {
+  MOZ_ASSERT(script->jitScript() == this);
+
+  if (hasCachedIonData()) {
+    return true;
+  }
+
+  Rooted<EnvironmentObject*> templateEnv(cx);
+  if (script->function()) {
+    RootedFunction fun(cx, script->function());
+
+    if (fun->needsNamedLambdaEnvironment()) {
+      templateEnv =
+          NamedLambdaObject::createTemplateObject(cx, fun, gc::TenuredHeap);
+      if (!templateEnv) {
+        return false;
+      }
+    }
+
+    if (fun->needsCallObject()) {
+      templateEnv = CallObject::createTemplateObject(cx, script, templateEnv,
+                                                     gc::TenuredHeap);
+      if (!templateEnv) {
+        return false;
+      }
+    }
+  }
+
+  IonBytecodeInfo bytecodeInfo = AnalyzeBytecodeForIon(cx, script);
+
+  UniquePtr<CachedIonData> data =
+      cx->make_unique<CachedIonData>(templateEnv, bytecodeInfo);
+  if (!data) {
+    return false;
+  }
+
+  cachedIonData_ = std::move(data);
+  return true;
+}
+
+void JitScript::setBaselineScriptImpl(JSScript* script,
+                                      BaselineScript* baselineScript) {
+  JSRuntime* rt = script->runtimeFromMainThread();
+  setBaselineScriptImpl(rt->defaultFreeOp(), script, baselineScript);
+}
+
+void JitScript::setBaselineScriptImpl(JSFreeOp* fop, JSScript* script,
+                                      BaselineScript* baselineScript) {
+  if (hasBaselineScript()) {
+    BaselineScript::preWriteBarrier(script->zone(), baselineScript_);
+    fop->removeCellMemory(script, baselineScript_->allocBytes(),
+                          MemoryUse::BaselineScript);
+    baselineScript_ = nullptr;
+  }
+
+  MOZ_ASSERT(ionScript_ == nullptr || ionScript_ == IonDisabledScriptPtr);
+
+  baselineScript_ = baselineScript;
+  if (hasBaselineScript()) {
+    AddCellMemory(script, baselineScript_->allocBytes(),
+                  MemoryUse::BaselineScript);
+  }
+
+  script->resetWarmUpResetCounter();
+  script->updateJitCodeRaw(fop->runtime());
+}
+
+void JitScript::setIonScriptImpl(JSScript* script, IonScript* ionScript) {
+  JSRuntime* rt = script->runtimeFromMainThread();
+  setIonScriptImpl(rt->defaultFreeOp(), script, ionScript);
+}
+
+void JitScript::setIonScriptImpl(JSFreeOp* fop, JSScript* script,
+                                 IonScript* ionScript) {
+  MOZ_ASSERT_IF(ionScript != IonDisabledScriptPtr,
+                !baselineScript()->hasPendingIonCompileTask());
+
+  if (hasIonScript()) {
+    IonScript::preWriteBarrier(script->zone(), ionScript_);
+    fop->removeCellMemory(script, ionScript_->allocBytes(),
+                          MemoryUse::IonScript);
+    ionScript_ = nullptr;
+  }
+
+  ionScript_ = ionScript;
+  MOZ_ASSERT_IF(hasIonScript(), hasBaselineScript());
+  if (hasIonScript()) {
+    AddCellMemory(script, ionScript_->allocBytes(), MemoryUse::IonScript);
+  }
+
+  script->updateJitCodeRaw(fop->runtime());
+}
+
+#ifdef JS_STRUCTURED_SPEW
+static bool HasEnteredCounters(ICEntry& entry) {
+  ICStub* stub = entry.firstStub();
+  if (stub && !stub->isFallback()) {
+    return true;
+  }
+  return false;
+}
+
+void jit::JitSpewBaselineICStats(JSScript* script, const char* dumpReason) {
+  MOZ_ASSERT(script->hasJitScript());
+  JSContext* cx = TlsContext.get();
+  AutoStructuredSpewer spew(cx, SpewChannel::BaselineICStats, script);
+  if (!spew) {
+    return;
+  }
+
+  JitScript* jitScript = script->jitScript();
+  spew->property("reason", dumpReason);
+  spew->beginListProperty("entries");
+  for (size_t i = 0; i < jitScript->numICEntries(); i++) {
+    ICEntry& entry = jitScript->icEntry(i);
+    if (!HasEnteredCounters(entry)) {
+      continue;
+    }
+
+    uint32_t pcOffset = entry.pcOffset();
+    jsbytecode* pc = entry.pc(script);
+
+    unsigned column;
+    unsigned int line = PCToLineNumber(script, pc, &column);
+
+    spew->beginObject();
+    spew->property("op", CodeName(JSOp(*pc)));
+    spew->property("pc", pcOffset);
+    spew->property("line", line);
+    spew->property("column", column);
+
+    spew->beginListProperty("counts");
+    ICStub* stub = entry.firstStub();
+    while (stub && !stub->isFallback()) {
+      uint32_t count = stub->enteredCount();
+      spew->value(count);
+      stub = stub->toCacheIRStub()->next();
+    }
+    spew->endList();
+    spew->property("fallback_count", entry.fallbackStub()->enteredCount());
+    spew->endObject();
+  }
+  spew->endList();
+}
+#endif
+
+static void MarkActiveJitScripts(JSContext* cx,
+                                 const JitActivationIterator& activation) {
+  for (OnlyJSJitFrameIter iter(activation); !iter.done(); ++iter) {
+    const JSJitFrameIter& frame = iter.frame();
+    switch (frame.type()) {
+      case FrameType::BaselineJS:
+        frame.script()->jitScript()->setActive();
+        break;
+      case FrameType::Exit:
+        if (frame.exitFrame()->is<LazyLinkExitFrameLayout>()) {
+          LazyLinkExitFrameLayout* ll =
+              frame.exitFrame()->as<LazyLinkExitFrameLayout>();
+          JSScript* script =
+              ScriptFromCalleeToken(ll->jsFrame()->calleeToken());
+          script->jitScript()->setActive();
+        }
+        break;
+      case FrameType::Bailout:
+      case FrameType::IonJS: {
+        // Keep the JitScript and BaselineScript around, since bailouts from
+        // the ion jitcode need to re-enter into the Baseline code.
+        frame.script()->jitScript()->setActive();
+        for (InlineFrameIterator inlineIter(cx, &frame); inlineIter.more();
+             ++inlineIter) {
+          inlineIter.script()->jitScript()->setActive();
+        }
+        break;
+      }
+      default:;
+    }
+  }
+}
+
+void jit::MarkActiveJitScripts(Zone* zone) {
+  if (zone->isAtomsZone()) {
+    return;
+  }
+  JSContext* cx = TlsContext.get();
+  for (JitActivationIterator iter(cx); !iter.done(); ++iter) {
+    if (iter->compartment()->zone() == zone) {
+      MarkActiveJitScripts(cx, iter);
+    }
+  }
+}
+
+InliningRoot* JitScript::getOrCreateInliningRoot(JSContext* cx,
+                                                 JSScript* script) {
+  if (!inliningRoot_) {
+    inliningRoot_ = js::MakeUnique<InliningRoot>(cx, script);
+    if (!inliningRoot_) {
+      ReportOutOfMemory(cx);
+      return nullptr;
+    }
+    icScript_.inliningRoot_ = inliningRoot_.get();
+  }
+  return inliningRoot_.get();
+}
+
+FallbackICStubSpace* ICScript::fallbackStubSpace() {
+  if (isInlined()) {
+    return inliningRoot_->fallbackStubSpace();
+  }
+  return outerJitScript()->fallbackStubSpace();
+}
+
+JitScript* ICScript::outerJitScript() {
+  MOZ_ASSERT(!isInlined());
+  uint8_t* ptr = reinterpret_cast<uint8_t*>(this);
+  return reinterpret_cast<JitScript*>(ptr - JitScript::offsetOfICScript());
+}
+
+#ifdef DEBUG
+// This hash is used to verify that we do not recompile after a
+// TranspiledCacheIR invalidation with the exact same ICs.
+//
+// It should change iff an ICEntry in this ICScript (or an ICScript
+// inlined into this ICScript) is modified such that we will make a
+// different decision in WarpScriptOracle::maybeInlineIC. This means:
+//
+// 1. The hash will change if we attach a new stub.
+// 2. The hash will change if we increment the entered count of any
+//    CacheIR stub other than the first.
+// 3. The hash will change if we increment the entered count of the
+//    fallback stub.
+//
+HashNumber ICScript::hash() {
+  HashNumber h = 0;
+  for (size_t i = 0; i < numICEntries(); i++) {
+    ICStub* stub = icEntry(i).firstStub();
+
+    // Hash the address of the first stub.
+    h = mozilla::AddToHash(h, stub);
+
+    // Hash the entered count of each subsequent CacheIRStub.
+    if (!stub->isFallback()) {
+      stub = stub->toCacheIRStub()->next();
+      while (!stub->isFallback()) {
+        h = mozilla::AddToHash(h, stub->enteredCount());
+        stub = stub->toCacheIRStub()->next();
+      }
+    }
+
+    // Hash the enteredCount of the fallback stub.
+    MOZ_ASSERT(stub->isFallback());
+    h = mozilla::AddToHash(h, stub->enteredCount());
+  }
+
+  if (inlinedChildren_) {
+    for (auto& callsite : *inlinedChildren_) {
+      h = mozilla::AddToHash(h, callsite.callee_->hash());
+    }
+  }
+  return h;
+}
+
+#endif