Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

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

1 files changed, 1253 insertions, 0 deletions

diff --git a/js/src/wasm/WasmCode.cpp b/js/src/wasm/WasmCode.cpp
new file mode 100644
index 0000000000..063d2a020c
--- /dev/null
+++ b/js/src/wasm/WasmCode.cpp
@@ -0,0 +1,1253 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ *
+ * Copyright 2016 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "wasm/WasmCode.h"
+
+#include "mozilla/Atomics.h"
+#include "mozilla/BinarySearch.h"
+#include "mozilla/EnumeratedRange.h"
+#include "mozilla/Sprintf.h"
+
+#include <algorithm>
+
+#include "jsnum.h"
+
+#include "jit/Disassemble.h"
+#include "jit/ExecutableAllocator.h"
+#include "jit/MacroAssembler.h"
+#include "jit/PerfSpewer.h"
+#include "util/Poison.h"
+#ifdef MOZ_VTUNE
+#  include "vtune/VTuneWrapper.h"
+#endif
+#include "wasm/WasmModule.h"
+#include "wasm/WasmProcess.h"
+#include "wasm/WasmSerialize.h"
+#include "wasm/WasmStubs.h"
+#include "wasm/WasmUtility.h"
+
+using namespace js;
+using namespace js::jit;
+using namespace js::wasm;
+using mozilla::BinarySearch;
+using mozilla::BinarySearchIf;
+using mozilla::MakeEnumeratedRange;
+using mozilla::PodAssign;
+
+size_t LinkData::SymbolicLinkArray::sizeOfExcludingThis(
+    MallocSizeOf mallocSizeOf) const {
+  size_t size = 0;
+  for (const Uint32Vector& offsets : *this) {
+    size += offsets.sizeOfExcludingThis(mallocSizeOf);
+  }
+  return size;
+}
+
+CodeSegment::~CodeSegment() {
+  if (unregisterOnDestroy_) {
+    UnregisterCodeSegment(this);
+  }
+}
+
+static uint32_t RoundupCodeLength(uint32_t codeLength) {
+  // AllocateExecutableMemory() requires a multiple of ExecutableCodePageSize.
+  return RoundUp(codeLength, ExecutableCodePageSize);
+}
+
+UniqueCodeBytes wasm::AllocateCodeBytes(uint32_t codeLength) {
+  if (codeLength > MaxCodeBytesPerProcess) {
+    return nullptr;
+  }
+
+  static_assert(MaxCodeBytesPerProcess <= INT32_MAX, "rounding won't overflow");
+  uint32_t roundedCodeLength = RoundupCodeLength(codeLength);
+
+  void* p =
+      AllocateExecutableMemory(roundedCodeLength, ProtectionSetting::Writable,
+                               MemCheckKind::MakeUndefined);
+
+  // If the allocation failed and the embedding gives us a last-ditch attempt
+  // to purge all memory (which, in gecko, does a purging GC/CC/GC), do that
+  // then retry the allocation.
+  if (!p) {
+    if (OnLargeAllocationFailure) {
+      OnLargeAllocationFailure();
+      p = AllocateExecutableMemory(roundedCodeLength,
+                                   ProtectionSetting::Writable,
+                                   MemCheckKind::MakeUndefined);
+    }
+  }
+
+  if (!p) {
+    return nullptr;
+  }
+
+  // Zero the padding.
+  memset(((uint8_t*)p) + codeLength, 0, roundedCodeLength - codeLength);
+
+  // We account for the bytes allocated in WasmModuleObject::create, where we
+  // have the necessary JSContext.
+
+  return UniqueCodeBytes((uint8_t*)p, FreeCode(roundedCodeLength));
+}
+
+bool CodeSegment::initialize(const CodeTier& codeTier) {
+  MOZ_ASSERT(!initialized());
+  codeTier_ = &codeTier;
+  MOZ_ASSERT(initialized());
+
+  // In the case of tiering, RegisterCodeSegment() immediately makes this code
+  // segment live to access from other threads executing the containing
+  // module. So only call once the CodeSegment is fully initialized.
+  if (!RegisterCodeSegment(this)) {
+    return false;
+  }
+
+  // This bool is only used by the destructor which cannot be called racily
+  // and so it is not a problem to mutate it after RegisterCodeSegment().
+  MOZ_ASSERT(!unregisterOnDestroy_);
+  unregisterOnDestroy_ = true;
+  return true;
+}
+
+const Code& CodeSegment::code() const {
+  MOZ_ASSERT(codeTier_);
+  return codeTier_->code();
+}
+
+void CodeSegment::addSizeOfMisc(MallocSizeOf mallocSizeOf, size_t* code) const {
+  *code += RoundupCodeLength(length());
+}
+
+void FreeCode::operator()(uint8_t* bytes) {
+  MOZ_ASSERT(codeLength);
+  MOZ_ASSERT(codeLength == RoundupCodeLength(codeLength));
+
+#ifdef MOZ_VTUNE
+  vtune::UnmarkBytes(bytes, codeLength);
+#endif
+  DeallocateExecutableMemory(bytes, codeLength);
+}
+
+bool wasm::StaticallyLink(const ModuleSegment& ms, const LinkData& linkData) {
+  for (LinkData::InternalLink link : linkData.internalLinks) {
+    CodeLabel label;
+    label.patchAt()->bind(link.patchAtOffset);
+    label.target()->bind(link.targetOffset);
+#ifdef JS_CODELABEL_LINKMODE
+    label.setLinkMode(static_cast<CodeLabel::LinkMode>(link.mode));
+#endif
+    Assembler::Bind(ms.base(), label);
+  }
+
+  if (!EnsureBuiltinThunksInitialized()) {
+    return false;
+  }
+
+  for (auto imm : MakeEnumeratedRange(SymbolicAddress::Limit)) {
+    const Uint32Vector& offsets = linkData.symbolicLinks[imm];
+    if (offsets.empty()) {
+      continue;
+    }
+
+    void* target = SymbolicAddressTarget(imm);
+    for (uint32_t offset : offsets) {
+      uint8_t* patchAt = ms.base() + offset;
+      Assembler::PatchDataWithValueCheck(CodeLocationLabel(patchAt),
+                                         PatchedImmPtr(target),
+                                         PatchedImmPtr((void*)-1));
+    }
+  }
+
+  return true;
+}
+
+void wasm::StaticallyUnlink(uint8_t* base, const LinkData& linkData) {
+  for (LinkData::InternalLink link : linkData.internalLinks) {
+    CodeLabel label;
+    label.patchAt()->bind(link.patchAtOffset);
+    label.target()->bind(-size_t(base));  // to reset immediate to null
+#ifdef JS_CODELABEL_LINKMODE
+    label.setLinkMode(static_cast<CodeLabel::LinkMode>(link.mode));
+#endif
+    Assembler::Bind(base, label);
+  }
+
+  for (auto imm : MakeEnumeratedRange(SymbolicAddress::Limit)) {
+    const Uint32Vector& offsets = linkData.symbolicLinks[imm];
+    if (offsets.empty()) {
+      continue;
+    }
+
+    void* target = SymbolicAddressTarget(imm);
+    for (uint32_t offset : offsets) {
+      uint8_t* patchAt = base + offset;
+      Assembler::PatchDataWithValueCheck(CodeLocationLabel(patchAt),
+                                         PatchedImmPtr((void*)-1),
+                                         PatchedImmPtr(target));
+    }
+  }
+}
+
+static bool AppendToString(const char* str, UTF8Bytes* bytes) {
+  return bytes->append(str, strlen(str)) && bytes->append('\0');
+}
+
+static void SendCodeRangesToProfiler(const ModuleSegment& ms,
+                                     const Metadata& metadata,
+                                     const CodeRangeVector& codeRanges) {
+  bool enabled = false;
+  enabled |= PerfEnabled();
+#ifdef MOZ_VTUNE
+  enabled |= vtune::IsProfilingActive();
+#endif
+  if (!enabled) {
+    return;
+  }
+
+  for (const CodeRange& codeRange : codeRanges) {
+    if (!codeRange.hasFuncIndex()) {
+      continue;
+    }
+
+    uintptr_t start = uintptr_t(ms.base() + codeRange.begin());
+    uintptr_t size = codeRange.end() - codeRange.begin();
+
+    UTF8Bytes name;
+    if (!metadata.getFuncNameStandalone(codeRange.funcIndex(), &name)) {
+      return;
+    }
+
+    // Avoid "unused" warnings
+    (void)start;
+    (void)size;
+
+    if (PerfEnabled()) {
+      const char* file = metadata.filename.get();
+      if (codeRange.isFunction()) {
+        if (!name.append('\0')) {
+          return;
+        }
+        unsigned line = codeRange.funcLineOrBytecode();
+        CollectPerfSpewerWasmFunctionMap(start, size, file, line, name.begin());
+      } else if (codeRange.isInterpEntry()) {
+        if (!AppendToString(" slow entry", &name)) {
+          return;
+        }
+        CollectPerfSpewerWasmMap(start, size, file, name.begin());
+      } else if (codeRange.isJitEntry()) {
+        if (!AppendToString(" fast entry", &name)) {
+          return;
+        }
+        CollectPerfSpewerWasmMap(start, size, file, name.begin());
+      } else if (codeRange.isImportInterpExit()) {
+        if (!AppendToString(" slow exit", &name)) {
+          return;
+        }
+        CollectPerfSpewerWasmMap(start, size, file, name.begin());
+      } else if (codeRange.isImportJitExit()) {
+        if (!AppendToString(" fast exit", &name)) {
+          return;
+        }
+        CollectPerfSpewerWasmMap(start, size, file, name.begin());
+      } else {
+        MOZ_CRASH("unhandled perf hasFuncIndex type");
+      }
+    }
+#ifdef MOZ_VTUNE
+    if (!vtune::IsProfilingActive()) {
+      continue;
+    }
+    if (!codeRange.isFunction()) {
+      continue;
+    }
+    if (!name.append('\0')) {
+      return;
+    }
+    vtune::MarkWasm(vtune::GenerateUniqueMethodID(), name.begin(), (void*)start,
+                    size);
+#endif
+  }
+}
+
+ModuleSegment::ModuleSegment(Tier tier, UniqueCodeBytes codeBytes,
+                             uint32_t codeLength, const LinkData& linkData)
+    : CodeSegment(std::move(codeBytes), codeLength, CodeSegment::Kind::Module),
+      tier_(tier),
+      trapCode_(base() + linkData.trapOffset) {}
+
+/* static */
+UniqueModuleSegment ModuleSegment::create(Tier tier, MacroAssembler& masm,
+                                          const LinkData& linkData) {
+  uint32_t codeLength = masm.bytesNeeded();
+
+  UniqueCodeBytes codeBytes = AllocateCodeBytes(codeLength);
+  if (!codeBytes) {
+    return nullptr;
+  }
+
+  masm.executableCopy(codeBytes.get());
+
+  return js::MakeUnique<ModuleSegment>(tier, std::move(codeBytes), codeLength,
+                                       linkData);
+}
+
+/* static */
+UniqueModuleSegment ModuleSegment::create(Tier tier, const Bytes& unlinkedBytes,
+                                          const LinkData& linkData) {
+  uint32_t codeLength = unlinkedBytes.length();
+
+  UniqueCodeBytes codeBytes = AllocateCodeBytes(codeLength);
+  if (!codeBytes) {
+    return nullptr;
+  }
+
+  memcpy(codeBytes.get(), unlinkedBytes.begin(), codeLength);
+
+  return js::MakeUnique<ModuleSegment>(tier, std::move(codeBytes), codeLength,
+                                       linkData);
+}
+
+bool ModuleSegment::initialize(const CodeTier& codeTier,
+                               const LinkData& linkData,
+                               const Metadata& metadata,
+                               const MetadataTier& metadataTier) {
+  if (!StaticallyLink(*this, linkData)) {
+    return false;
+  }
+
+  // Optimized compilation finishes on a background thread, so we must make sure
+  // to flush the icaches of all the executing threads.
+  // Reprotect the whole region to avoid having separate RW and RX mappings.
+  if (!ExecutableAllocator::makeExecutableAndFlushICache(
+          base(), RoundupCodeLength(length()))) {
+    return false;
+  }
+
+  SendCodeRangesToProfiler(*this, metadata, metadataTier.codeRanges);
+
+  // See comments in CodeSegment::initialize() for why this must be last.
+  return CodeSegment::initialize(codeTier);
+}
+
+void ModuleSegment::addSizeOfMisc(mozilla::MallocSizeOf mallocSizeOf,
+                                  size_t* code, size_t* data) const {
+  CodeSegment::addSizeOfMisc(mallocSizeOf, code);
+  *data += mallocSizeOf(this);
+}
+
+const CodeRange* ModuleSegment::lookupRange(const void* pc) const {
+  return codeTier().lookupRange(pc);
+}
+
+size_t CacheableChars::sizeOfExcludingThis(MallocSizeOf mallocSizeOf) const {
+  return mallocSizeOf(get());
+}
+
+size_t MetadataTier::sizeOfExcludingThis(MallocSizeOf mallocSizeOf) const {
+  return funcToCodeRange.sizeOfExcludingThis(mallocSizeOf) +
+         codeRanges.sizeOfExcludingThis(mallocSizeOf) +
+         callSites.sizeOfExcludingThis(mallocSizeOf) +
+         tryNotes.sizeOfExcludingThis(mallocSizeOf) +
+         trapSites.sizeOfExcludingThis(mallocSizeOf) +
+         funcImports.sizeOfExcludingThis(mallocSizeOf) +
+         funcExports.sizeOfExcludingThis(mallocSizeOf);
+}
+
+UniqueLazyStubSegment LazyStubSegment::create(const CodeTier& codeTier,
+                                              size_t length) {
+  UniqueCodeBytes codeBytes = AllocateCodeBytes(length);
+  if (!codeBytes) {
+    return nullptr;
+  }
+
+  auto segment = js::MakeUnique<LazyStubSegment>(std::move(codeBytes), length);
+  if (!segment || !segment->initialize(codeTier)) {
+    return nullptr;
+  }
+
+  return segment;
+}
+
+bool LazyStubSegment::hasSpace(size_t bytes) const {
+  MOZ_ASSERT(AlignBytesNeeded(bytes) == bytes);
+  return bytes <= length() && usedBytes_ <= length() - bytes;
+}
+
+bool LazyStubSegment::addStubs(const Metadata& metadata, size_t codeLength,
+                               const Uint32Vector& funcExportIndices,
+                               const FuncExportVector& funcExports,
+                               const CodeRangeVector& codeRanges,
+                               uint8_t** codePtr,
+                               size_t* indexFirstInsertedCodeRange) {
+  MOZ_ASSERT(hasSpace(codeLength));
+
+  size_t offsetInSegment = usedBytes_;
+  *codePtr = base() + usedBytes_;
+  usedBytes_ += codeLength;
+
+  *indexFirstInsertedCodeRange = codeRanges_.length();
+
+  if (!codeRanges_.reserve(codeRanges_.length() + 2 * codeRanges.length())) {
+    return false;
+  }
+
+  size_t i = 0;
+  for (uint32_t funcExportIndex : funcExportIndices) {
+    const FuncExport& fe = funcExports[funcExportIndex];
+    const FuncType& funcType = metadata.getFuncExportType(fe);
+    const CodeRange& interpRange = codeRanges[i];
+    MOZ_ASSERT(interpRange.isInterpEntry());
+    MOZ_ASSERT(interpRange.funcIndex() ==
+               funcExports[funcExportIndex].funcIndex());
+
+    codeRanges_.infallibleAppend(interpRange);
+    codeRanges_.back().offsetBy(offsetInSegment);
+    i++;
+
+    if (!funcType.canHaveJitEntry()) {
+      continue;
+    }
+
+    const CodeRange& jitRange = codeRanges[i];
+    MOZ_ASSERT(jitRange.isJitEntry());
+    MOZ_ASSERT(jitRange.funcIndex() == interpRange.funcIndex());
+
+    codeRanges_.infallibleAppend(jitRange);
+    codeRanges_.back().offsetBy(offsetInSegment);
+    i++;
+  }
+
+  return true;
+}
+
+const CodeRange* LazyStubSegment::lookupRange(const void* pc) const {
+  // Do not search if the search will not find anything.  There can be many
+  // segments, each with many entries.
+  if (pc < base() || pc >= base() + length()) {
+    return nullptr;
+  }
+  return LookupInSorted(codeRanges_,
+                        CodeRange::OffsetInCode((uint8_t*)pc - base()));
+}
+
+void LazyStubSegment::addSizeOfMisc(MallocSizeOf mallocSizeOf, size_t* code,
+                                    size_t* data) const {
+  CodeSegment::addSizeOfMisc(mallocSizeOf, code);
+  *data += codeRanges_.sizeOfExcludingThis(mallocSizeOf);
+  *data += mallocSizeOf(this);
+}
+
+// When allocating a single stub to a page, we should not always place the stub
+// at the beginning of the page as the stubs will tend to thrash the icache by
+// creating conflicts (everything ends up in the same cache set).  Instead,
+// locate stubs at different line offsets up to 3/4 the system page size (the
+// code allocation quantum).
+//
+// This may be called on background threads, hence the atomic.
+
+static void PadCodeForSingleStub(MacroAssembler& masm) {
+  // Assume 64B icache line size
+  static uint8_t zeroes[64];
+
+  // The counter serves only to spread the code out, it has no other meaning and
+  // can wrap around.
+  static mozilla::Atomic<uint32_t, mozilla::MemoryOrdering::ReleaseAcquire>
+      counter(0);
+
+  uint32_t maxPadLines = ((gc::SystemPageSize() * 3) / 4) / sizeof(zeroes);
+  uint32_t padLines = counter++ % maxPadLines;
+  for (uint32_t i = 0; i < padLines; i++) {
+    masm.appendRawCode(zeroes, sizeof(zeroes));
+  }
+}
+
+static constexpr unsigned LAZY_STUB_LIFO_DEFAULT_CHUNK_SIZE = 8 * 1024;
+
+bool LazyStubTier::createManyEntryStubs(const Uint32Vector& funcExportIndices,
+                                        const Metadata& metadata,
+                                        const CodeTier& codeTier,
+                                        size_t* stubSegmentIndex) {
+  MOZ_ASSERT(funcExportIndices.length());
+
+  LifoAlloc lifo(LAZY_STUB_LIFO_DEFAULT_CHUNK_SIZE);
+  TempAllocator alloc(&lifo);
+  JitContext jitContext;
+  WasmMacroAssembler masm(alloc);
+
+  if (funcExportIndices.length() == 1) {
+    PadCodeForSingleStub(masm);
+  }
+
+  const MetadataTier& metadataTier = codeTier.metadata();
+  const FuncExportVector& funcExports = metadataTier.funcExports;
+  uint8_t* moduleSegmentBase = codeTier.segment().base();
+
+  CodeRangeVector codeRanges;
+  DebugOnly<uint32_t> numExpectedRanges = 0;
+  for (uint32_t funcExportIndex : funcExportIndices) {
+    const FuncExport& fe = funcExports[funcExportIndex];
+    const FuncType& funcType = metadata.getFuncExportType(fe);
+    // Exports that don't support a jit entry get only the interp entry.
+    numExpectedRanges += (funcType.canHaveJitEntry() ? 2 : 1);
+    void* calleePtr =
+        moduleSegmentBase + metadataTier.codeRange(fe).funcUncheckedCallEntry();
+    Maybe<ImmPtr> callee;
+    callee.emplace(calleePtr, ImmPtr::NoCheckToken());
+    if (!GenerateEntryStubs(masm, funcExportIndex, fe, funcType, callee,
+                            /* asmjs */ false, &codeRanges)) {
+      return false;
+    }
+  }
+  MOZ_ASSERT(codeRanges.length() == numExpectedRanges,
+             "incorrect number of entries per function");
+
+  masm.finish();
+
+  MOZ_ASSERT(masm.callSites().empty());
+  MOZ_ASSERT(masm.callSiteTargets().empty());
+  MOZ_ASSERT(masm.trapSites().empty());
+  MOZ_ASSERT(masm.tryNotes().empty());
+
+  if (masm.oom()) {
+    return false;
+  }
+
+  size_t codeLength = LazyStubSegment::AlignBytesNeeded(masm.bytesNeeded());
+
+  if (!stubSegments_.length() ||
+      !stubSegments_[lastStubSegmentIndex_]->hasSpace(codeLength)) {
+    size_t newSegmentSize = std::max(codeLength, ExecutableCodePageSize);
+    UniqueLazyStubSegment newSegment =
+        LazyStubSegment::create(codeTier, newSegmentSize);
+    if (!newSegment) {
+      return false;
+    }
+    lastStubSegmentIndex_ = stubSegments_.length();
+    if (!stubSegments_.emplaceBack(std::move(newSegment))) {
+      return false;
+    }
+  }
+
+  LazyStubSegment* segment = stubSegments_[lastStubSegmentIndex_].get();
+  *stubSegmentIndex = lastStubSegmentIndex_;
+
+  size_t interpRangeIndex;
+  uint8_t* codePtr = nullptr;
+  if (!segment->addStubs(metadata, codeLength, funcExportIndices, funcExports,
+                         codeRanges, &codePtr, &interpRangeIndex)) {
+    return false;
+  }
+
+  masm.executableCopy(codePtr);
+  PatchDebugSymbolicAccesses(codePtr, masm);
+  memset(codePtr + masm.bytesNeeded(), 0, codeLength - masm.bytesNeeded());
+
+  for (const CodeLabel& label : masm.codeLabels()) {
+    Assembler::Bind(codePtr, label);
+  }
+
+  if (!ExecutableAllocator::makeExecutableAndFlushICache(codePtr, codeLength)) {
+    return false;
+  }
+
+  // Create lazy function exports for funcIndex -> entry lookup.
+  if (!exports_.reserve(exports_.length() + funcExportIndices.length())) {
+    return false;
+  }
+
+  for (uint32_t funcExportIndex : funcExportIndices) {
+    const FuncExport& fe = funcExports[funcExportIndex];
+    const FuncType& funcType = metadata.getFuncExportType(fe);
+
+    DebugOnly<CodeRange> cr = segment->codeRanges()[interpRangeIndex];
+    MOZ_ASSERT(cr.value.isInterpEntry());
+    MOZ_ASSERT(cr.value.funcIndex() == fe.funcIndex());
+
+    LazyFuncExport lazyExport(fe.funcIndex(), *stubSegmentIndex,
+                              interpRangeIndex);
+
+    size_t exportIndex;
+    const uint32_t targetFunctionIndex = fe.funcIndex();
+    MOZ_ALWAYS_FALSE(BinarySearchIf(
+        exports_, 0, exports_.length(),
+        [targetFunctionIndex](const LazyFuncExport& funcExport) {
+          return targetFunctionIndex - funcExport.funcIndex;
+        },
+        &exportIndex));
+    MOZ_ALWAYS_TRUE(
+        exports_.insert(exports_.begin() + exportIndex, std::move(lazyExport)));
+
+    // Exports that don't support a jit entry get only the interp entry.
+    interpRangeIndex += (funcType.canHaveJitEntry() ? 2 : 1);
+  }
+
+  return true;
+}
+
+bool LazyStubTier::createOneEntryStub(uint32_t funcExportIndex,
+                                      const Metadata& metadata,
+                                      const CodeTier& codeTier) {
+  Uint32Vector funcExportIndexes;
+  if (!funcExportIndexes.append(funcExportIndex)) {
+    return false;
+  }
+
+  size_t stubSegmentIndex;
+  if (!createManyEntryStubs(funcExportIndexes, metadata, codeTier,
+                            &stubSegmentIndex)) {
+    return false;
+  }
+
+  const UniqueLazyStubSegment& segment = stubSegments_[stubSegmentIndex];
+  const CodeRangeVector& codeRanges = segment->codeRanges();
+
+  const FuncExport& fe = codeTier.metadata().funcExports[funcExportIndex];
+  const FuncType& funcType = metadata.getFuncExportType(fe);
+
+  // Exports that don't support a jit entry get only the interp entry.
+  if (!funcType.canHaveJitEntry()) {
+    MOZ_ASSERT(codeRanges.length() >= 1);
+    MOZ_ASSERT(codeRanges.back().isInterpEntry());
+    return true;
+  }
+
+  MOZ_ASSERT(codeRanges.length() >= 2);
+  MOZ_ASSERT(codeRanges[codeRanges.length() - 2].isInterpEntry());
+
+  const CodeRange& cr = codeRanges[codeRanges.length() - 1];
+  MOZ_ASSERT(cr.isJitEntry());
+
+  codeTier.code().setJitEntry(cr.funcIndex(), segment->base() + cr.begin());
+  return true;
+}
+
+bool LazyStubTier::createTier2(const Uint32Vector& funcExportIndices,
+                               const Metadata& metadata,
+                               const CodeTier& codeTier,
+                               Maybe<size_t>* outStubSegmentIndex) {
+  if (!funcExportIndices.length()) {
+    return true;
+  }
+
+  size_t stubSegmentIndex;
+  if (!createManyEntryStubs(funcExportIndices, metadata, codeTier,
+                            &stubSegmentIndex)) {
+    return false;
+  }
+
+  outStubSegmentIndex->emplace(stubSegmentIndex);
+  return true;
+}
+
+void LazyStubTier::setJitEntries(const Maybe<size_t>& stubSegmentIndex,
+                                 const Code& code) {
+  if (!stubSegmentIndex) {
+    return;
+  }
+  const UniqueLazyStubSegment& segment = stubSegments_[*stubSegmentIndex];
+  for (const CodeRange& cr : segment->codeRanges()) {
+    if (!cr.isJitEntry()) {
+      continue;
+    }
+    code.setJitEntry(cr.funcIndex(), segment->base() + cr.begin());
+  }
+}
+
+bool LazyStubTier::hasEntryStub(uint32_t funcIndex) const {
+  size_t match;
+  return BinarySearchIf(
+      exports_, 0, exports_.length(),
+      [funcIndex](const LazyFuncExport& funcExport) {
+        return funcIndex - funcExport.funcIndex;
+      },
+      &match);
+}
+
+void* LazyStubTier::lookupInterpEntry(uint32_t funcIndex) const {
+  size_t match;
+  if (!BinarySearchIf(
+          exports_, 0, exports_.length(),
+          [funcIndex](const LazyFuncExport& funcExport) {
+            return funcIndex - funcExport.funcIndex;
+          },
+          &match)) {
+    return nullptr;
+  }
+  const LazyFuncExport& fe = exports_[match];
+  const LazyStubSegment& stub = *stubSegments_[fe.lazyStubSegmentIndex];
+  return stub.base() + stub.codeRanges()[fe.funcCodeRangeIndex].begin();
+}
+
+void LazyStubTier::addSizeOfMisc(MallocSizeOf mallocSizeOf, size_t* code,
+                                 size_t* data) const {
+  *data += sizeof(*this);
+  *data += exports_.sizeOfExcludingThis(mallocSizeOf);
+  for (const UniqueLazyStubSegment& stub : stubSegments_) {
+    stub->addSizeOfMisc(mallocSizeOf, code, data);
+  }
+}
+
+size_t Metadata::sizeOfExcludingThis(MallocSizeOf mallocSizeOf) const {
+  return types->sizeOfExcludingThis(mallocSizeOf) +
+         globals.sizeOfExcludingThis(mallocSizeOf) +
+         tables.sizeOfExcludingThis(mallocSizeOf) +
+         tags.sizeOfExcludingThis(mallocSizeOf) +
+         funcNames.sizeOfExcludingThis(mallocSizeOf) +
+         filename.sizeOfExcludingThis(mallocSizeOf) +
+         sourceMapURL.sizeOfExcludingThis(mallocSizeOf);
+}
+
+struct ProjectFuncIndex {
+  const FuncExportVector& funcExports;
+  explicit ProjectFuncIndex(const FuncExportVector& funcExports)
+      : funcExports(funcExports) {}
+  uint32_t operator[](size_t index) const {
+    return funcExports[index].funcIndex();
+  }
+};
+
+FuncExport& MetadataTier::lookupFuncExport(
+    uint32_t funcIndex, size_t* funcExportIndex /* = nullptr */) {
+  size_t match;
+  if (!BinarySearch(ProjectFuncIndex(funcExports), 0, funcExports.length(),
+                    funcIndex, &match)) {
+    MOZ_CRASH("missing function export");
+  }
+  if (funcExportIndex) {
+    *funcExportIndex = match;
+  }
+  return funcExports[match];
+}
+
+const FuncExport& MetadataTier::lookupFuncExport(
+    uint32_t funcIndex, size_t* funcExportIndex) const {
+  return const_cast<MetadataTier*>(this)->lookupFuncExport(funcIndex,
+                                                           funcExportIndex);
+}
+
+static bool AppendName(const Bytes& namePayload, const Name& name,
+                       UTF8Bytes* bytes) {
+  MOZ_RELEASE_ASSERT(name.offsetInNamePayload <= namePayload.length());
+  MOZ_RELEASE_ASSERT(name.length <=
+                     namePayload.length() - name.offsetInNamePayload);
+  return bytes->append(
+      (const char*)namePayload.begin() + name.offsetInNamePayload, name.length);
+}
+
+static bool AppendFunctionIndexName(uint32_t funcIndex, UTF8Bytes* bytes) {
+  const char beforeFuncIndex[] = "wasm-function[";
+  const char afterFuncIndex[] = "]";
+
+  Int32ToCStringBuf cbuf;
+  size_t funcIndexStrLen;
+  const char* funcIndexStr =
+      Uint32ToCString(&cbuf, funcIndex, &funcIndexStrLen);
+  MOZ_ASSERT(funcIndexStr);
+
+  return bytes->append(beforeFuncIndex, strlen(beforeFuncIndex)) &&
+         bytes->append(funcIndexStr, funcIndexStrLen) &&
+         bytes->append(afterFuncIndex, strlen(afterFuncIndex));
+}
+
+bool Metadata::getFuncName(NameContext ctx, uint32_t funcIndex,
+                           UTF8Bytes* name) const {
+  if (moduleName && moduleName->length != 0) {
+    if (!AppendName(namePayload->bytes, *moduleName, name)) {
+      return false;
+    }
+    if (!name->append('.')) {
+      return false;
+    }
+  }
+
+  if (funcIndex < funcNames.length() && funcNames[funcIndex].length != 0) {
+    return AppendName(namePayload->bytes, funcNames[funcIndex], name);
+  }
+
+  if (ctx == NameContext::BeforeLocation) {
+    return true;
+  }
+
+  return AppendFunctionIndexName(funcIndex, name);
+}
+
+bool CodeTier::initialize(const Code& code, const LinkData& linkData,
+                          const Metadata& metadata) {
+  MOZ_ASSERT(!initialized());
+  code_ = &code;
+
+  MOZ_ASSERT(lazyStubs_.readLock()->entryStubsEmpty());
+
+  // See comments in CodeSegment::initialize() for why this must be last.
+  if (!segment_->initialize(*this, linkData, metadata, *metadata_)) {
+    return false;
+  }
+
+  MOZ_ASSERT(initialized());
+  return true;
+}
+
+void CodeTier::addSizeOfMisc(MallocSizeOf mallocSizeOf, size_t* code,
+                             size_t* data) const {
+  segment_->addSizeOfMisc(mallocSizeOf, code, data);
+  lazyStubs_.readLock()->addSizeOfMisc(mallocSizeOf, code, data);
+  *data += metadata_->sizeOfExcludingThis(mallocSizeOf);
+}
+
+const CodeRange* CodeTier::lookupRange(const void* pc) const {
+  CodeRange::OffsetInCode target((uint8_t*)pc - segment_->base());
+  return LookupInSorted(metadata_->codeRanges, target);
+}
+
+const wasm::TryNote* CodeTier::lookupTryNote(const void* pc) const {
+  size_t target = (uint8_t*)pc - segment_->base();
+  const TryNoteVector& tryNotes = metadata_->tryNotes;
+
+  // We find the first hit (there may be multiple) to obtain the innermost
+  // handler, which is why we cannot binary search here.
+  for (const auto& tryNote : tryNotes) {
+    if (tryNote.offsetWithinTryBody(target)) {
+      return &tryNote;
+    }
+  }
+
+  return nullptr;
+}
+
+bool JumpTables::init(CompileMode mode, const ModuleSegment& ms,
+                      const CodeRangeVector& codeRanges) {
+  static_assert(JSScript::offsetOfJitCodeRaw() == 0,
+                "wasm fast jit entry is at (void*) jit[funcIndex]");
+
+  mode_ = mode;
+
+  size_t numFuncs = 0;
+  for (const CodeRange& cr : codeRanges) {
+    if (cr.isFunction()) {
+      numFuncs++;
+    }
+  }
+
+  numFuncs_ = numFuncs;
+
+  if (mode_ == CompileMode::Tier1) {
+    tiering_ = TablePointer(js_pod_calloc<void*>(numFuncs));
+    if (!tiering_) {
+      return false;
+    }
+  }
+
+  // The number of jit entries is overestimated, but it is simpler when
+  // filling/looking up the jit entries and safe (worst case we'll crash
+  // because of a null deref when trying to call the jit entry of an
+  // unexported function).
+  jit_ = TablePointer(js_pod_calloc<void*>(numFuncs));
+  if (!jit_) {
+    return false;
+  }
+
+  uint8_t* codeBase = ms.base();
+  for (const CodeRange& cr : codeRanges) {
+    if (cr.isFunction()) {
+      setTieringEntry(cr.funcIndex(), codeBase + cr.funcTierEntry());
+    } else if (cr.isJitEntry()) {
+      setJitEntry(cr.funcIndex(), codeBase + cr.begin());
+    }
+  }
+  return true;
+}
+
+Code::Code(UniqueCodeTier tier1, const Metadata& metadata,
+           JumpTables&& maybeJumpTables)
+    : tier1_(std::move(tier1)),
+      metadata_(&metadata),
+      profilingLabels_(mutexid::WasmCodeProfilingLabels,
+                       CacheableCharsVector()),
+      jumpTables_(std::move(maybeJumpTables)) {}
+
+bool Code::initialize(const LinkData& linkData) {
+  MOZ_ASSERT(!initialized());
+
+  if (!tier1_->initialize(*this, linkData, *metadata_)) {
+    return false;
+  }
+
+  MOZ_ASSERT(initialized());
+  return true;
+}
+
+bool Code::setAndBorrowTier2(UniqueCodeTier tier2, const LinkData& linkData,
+                             const CodeTier** borrowedTier) const {
+  MOZ_RELEASE_ASSERT(!hasTier2());
+  MOZ_RELEASE_ASSERT(tier2->tier() == Tier::Optimized &&
+                     tier1_->tier() == Tier::Baseline);
+
+  if (!tier2->initialize(*this, linkData, *metadata_)) {
+    return false;
+  }
+
+  tier2_ = std::move(tier2);
+  *borrowedTier = &*tier2_;
+
+  return true;
+}
+
+void Code::commitTier2() const {
+  MOZ_RELEASE_ASSERT(!hasTier2());
+  hasTier2_ = true;
+  MOZ_ASSERT(hasTier2());
+
+  // To maintain the invariant that tier2_ is never read without the tier having
+  // been committed, this checks tier2_ here instead of before setting hasTier2_
+  // (as would be natural).  See comment in WasmCode.h.
+  MOZ_RELEASE_ASSERT(tier2_.get());
+}
+
+uint32_t Code::getFuncIndex(JSFunction* fun) const {
+  MOZ_ASSERT(fun->isWasm() || fun->isAsmJSNative());
+  if (!fun->isWasmWithJitEntry()) {
+    return fun->wasmFuncIndex();
+  }
+  return jumpTables_.funcIndexFromJitEntry(fun->wasmJitEntry());
+}
+
+Tiers Code::tiers() const {
+  if (hasTier2()) {
+    return Tiers(tier1_->tier(), tier2_->tier());
+  }
+  return Tiers(tier1_->tier());
+}
+
+bool Code::hasTier(Tier t) const {
+  if (hasTier2() && tier2_->tier() == t) {
+    return true;
+  }
+  return tier1_->tier() == t;
+}
+
+Tier Code::stableTier() const { return tier1_->tier(); }
+
+Tier Code::bestTier() const {
+  if (hasTier2()) {
+    return tier2_->tier();
+  }
+  return tier1_->tier();
+}
+
+const CodeTier& Code::codeTier(Tier tier) const {
+  switch (tier) {
+    case Tier::Baseline:
+      if (tier1_->tier() == Tier::Baseline) {
+        MOZ_ASSERT(tier1_->initialized());
+        return *tier1_;
+      }
+      MOZ_CRASH("No code segment at this tier");
+    case Tier::Optimized:
+      if (tier1_->tier() == Tier::Optimized) {
+        MOZ_ASSERT(tier1_->initialized());
+        return *tier1_;
+      }
+      // It is incorrect to ask for the optimized tier without there being such
+      // a tier and the tier having been committed.  The guard here could
+      // instead be `if (hasTier2()) ... ` but codeTier(t) should not be called
+      // in contexts where that test is necessary.
+      MOZ_RELEASE_ASSERT(hasTier2());
+      MOZ_ASSERT(tier2_->initialized());
+      return *tier2_;
+  }
+  MOZ_CRASH();
+}
+
+bool Code::containsCodePC(const void* pc) const {
+  for (Tier t : tiers()) {
+    const ModuleSegment& ms = segment(t);
+    if (ms.containsCodePC(pc)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+struct CallSiteRetAddrOffset {
+  const CallSiteVector& callSites;
+  explicit CallSiteRetAddrOffset(const CallSiteVector& callSites)
+      : callSites(callSites) {}
+  uint32_t operator[](size_t index) const {
+    return callSites[index].returnAddressOffset();
+  }
+};
+
+const CallSite* Code::lookupCallSite(void* returnAddress) const {
+  for (Tier t : tiers()) {
+    uint32_t target = ((uint8_t*)returnAddress) - segment(t).base();
+    size_t lowerBound = 0;
+    size_t upperBound = metadata(t).callSites.length();
+
+    size_t match;
+    if (BinarySearch(CallSiteRetAddrOffset(metadata(t).callSites), lowerBound,
+                     upperBound, target, &match)) {
+      return &metadata(t).callSites[match];
+    }
+  }
+
+  return nullptr;
+}
+
+const CodeRange* Code::lookupFuncRange(void* pc) const {
+  for (Tier t : tiers()) {
+    const CodeRange* result = codeTier(t).lookupRange(pc);
+    if (result && result->isFunction()) {
+      return result;
+    }
+  }
+  return nullptr;
+}
+
+const StackMap* Code::lookupStackMap(uint8_t* nextPC) const {
+  for (Tier t : tiers()) {
+    const StackMap* result = metadata(t).stackMaps.findMap(nextPC);
+    if (result) {
+      return result;
+    }
+  }
+  return nullptr;
+}
+
+const wasm::TryNote* Code::lookupTryNote(void* pc, Tier* tier) const {
+  for (Tier t : tiers()) {
+    const TryNote* result = codeTier(t).lookupTryNote(pc);
+    if (result) {
+      *tier = t;
+      return result;
+    }
+  }
+  return nullptr;
+}
+
+struct TrapSitePCOffset {
+  const TrapSiteVector& trapSites;
+  explicit TrapSitePCOffset(const TrapSiteVector& trapSites)
+      : trapSites(trapSites) {}
+  uint32_t operator[](size_t index) const { return trapSites[index].pcOffset; }
+};
+
+bool Code::lookupTrap(void* pc, Trap* trapOut, BytecodeOffset* bytecode) const {
+  for (Tier t : tiers()) {
+    uint32_t target = ((uint8_t*)pc) - segment(t).base();
+    const TrapSiteVectorArray& trapSitesArray = metadata(t).trapSites;
+    for (Trap trap : MakeEnumeratedRange(Trap::Limit)) {
+      const TrapSiteVector& trapSites = trapSitesArray[trap];
+
+      size_t upperBound = trapSites.length();
+      size_t match;
+      if (BinarySearch(TrapSitePCOffset(trapSites), 0, upperBound, target,
+                       &match)) {
+        MOZ_ASSERT(segment(t).containsCodePC(pc));
+        *trapOut = trap;
+        *bytecode = trapSites[match].bytecode;
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
+// When enabled, generate profiling labels for every name in funcNames_ that is
+// the name of some Function CodeRange. This involves malloc() so do it now
+// since, once we start sampling, we'll be in a signal-handing context where we
+// cannot malloc.
+void Code::ensureProfilingLabels(bool profilingEnabled) const {
+  auto labels = profilingLabels_.lock();
+
+  if (!profilingEnabled) {
+    labels->clear();
+    return;
+  }
+
+  if (!labels->empty()) {
+    return;
+  }
+
+  // Any tier will do, we only need tier-invariant data that are incidentally
+  // stored with the code ranges.
+
+  for (const CodeRange& codeRange : metadata(stableTier()).codeRanges) {
+    if (!codeRange.isFunction()) {
+      continue;
+    }
+
+    Int32ToCStringBuf cbuf;
+    size_t bytecodeStrLen;
+    const char* bytecodeStr =
+        Uint32ToCString(&cbuf, codeRange.funcLineOrBytecode(), &bytecodeStrLen);
+    MOZ_ASSERT(bytecodeStr);
+
+    UTF8Bytes name;
+    if (!metadata().getFuncNameStandalone(codeRange.funcIndex(), &name)) {
+      return;
+    }
+    if (!name.append(" (", 2)) {
+      return;
+    }
+
+    if (const char* filename = metadata().filename.get()) {
+      if (!name.append(filename, strlen(filename))) {
+        return;
+      }
+    } else {
+      if (!name.append('?')) {
+        return;
+      }
+    }
+
+    if (!name.append(':') || !name.append(bytecodeStr, bytecodeStrLen) ||
+        !name.append(")\0", 2)) {
+      return;
+    }
+
+    UniqueChars label(name.extractOrCopyRawBuffer());
+    if (!label) {
+      return;
+    }
+
+    if (codeRange.funcIndex() >= labels->length()) {
+      if (!labels->resize(codeRange.funcIndex() + 1)) {
+        return;
+      }
+    }
+
+    ((CacheableCharsVector&)labels)[codeRange.funcIndex()] = std::move(label);
+  }
+}
+
+const char* Code::profilingLabel(uint32_t funcIndex) const {
+  auto labels = profilingLabels_.lock();
+
+  if (funcIndex >= labels->length() ||
+      !((CacheableCharsVector&)labels)[funcIndex]) {
+    return "?";
+  }
+  return ((CacheableCharsVector&)labels)[funcIndex].get();
+}
+
+void Code::addSizeOfMiscIfNotSeen(MallocSizeOf mallocSizeOf,
+                                  Metadata::SeenSet* seenMetadata,
+                                  Code::SeenSet* seenCode, size_t* code,
+                                  size_t* data) const {
+  auto p = seenCode->lookupForAdd(this);
+  if (p) {
+    return;
+  }
+  bool ok = seenCode->add(p, this);
+  (void)ok;  // oh well
+
+  *data += mallocSizeOf(this) +
+           metadata().sizeOfIncludingThisIfNotSeen(mallocSizeOf, seenMetadata) +
+           profilingLabels_.lock()->sizeOfExcludingThis(mallocSizeOf) +
+           jumpTables_.sizeOfMiscExcludingThis();
+
+  for (auto t : tiers()) {
+    codeTier(t).addSizeOfMisc(mallocSizeOf, code, data);
+  }
+}
+
+void Code::disassemble(JSContext* cx, Tier tier, int kindSelection,
+                       PrintCallback printString) const {
+  const MetadataTier& metadataTier = metadata(tier);
+  const CodeTier& codeTier = this->codeTier(tier);
+  const ModuleSegment& segment = codeTier.segment();
+
+  for (const CodeRange& range : metadataTier.codeRanges) {
+    if (kindSelection & (1 << range.kind())) {
+      MOZ_ASSERT(range.begin() < segment.length());
+      MOZ_ASSERT(range.end() < segment.length());
+
+      const char* kind;
+      char kindbuf[128];
+      switch (range.kind()) {
+        case CodeRange::Function:
+          kind = "Function";
+          break;
+        case CodeRange::InterpEntry:
+          kind = "InterpEntry";
+          break;
+        case CodeRange::JitEntry:
+          kind = "JitEntry";
+          break;
+        case CodeRange::ImportInterpExit:
+          kind = "ImportInterpExit";
+          break;
+        case CodeRange::ImportJitExit:
+          kind = "ImportJitExit";
+          break;
+        default:
+          SprintfLiteral(kindbuf, "CodeRange::Kind(%d)", range.kind());
+          kind = kindbuf;
+          break;
+      }
+      const char* separator =
+          "\n--------------------------------------------------\n";
+      // The buffer is quite large in order to accomodate mangled C++ names;
+      // lengths over 3500 have been observed in the wild.
+      char buf[4096];
+      if (range.hasFuncIndex()) {
+        const char* funcName = "(unknown)";
+        UTF8Bytes namebuf;
+        if (metadata().getFuncNameStandalone(range.funcIndex(), &namebuf) &&
+            namebuf.append('\0')) {
+          funcName = namebuf.begin();
+        }
+        SprintfLiteral(buf, "%sKind = %s, index = %d, name = %s:\n", separator,
+                       kind, range.funcIndex(), funcName);
+      } else {
+        SprintfLiteral(buf, "%sKind = %s\n", separator, kind);
+      }
+      printString(buf);
+
+      uint8_t* theCode = segment.base() + range.begin();
+      jit::Disassemble(theCode, range.end() - range.begin(), printString);
+    }
+  }
+}
+
+void wasm::PatchDebugSymbolicAccesses(uint8_t* codeBase, MacroAssembler& masm) {
+#ifdef WASM_CODEGEN_DEBUG
+  for (auto& access : masm.symbolicAccesses()) {
+    switch (access.target) {
+      case SymbolicAddress::PrintI32:
+      case SymbolicAddress::PrintPtr:
+      case SymbolicAddress::PrintF32:
+      case SymbolicAddress::PrintF64:
+      case SymbolicAddress::PrintText:
+        break;
+      default:
+        MOZ_CRASH("unexpected symbol in PatchDebugSymbolicAccesses");
+    }
+    ABIFunctionType abiType;
+    void* target = AddressOf(access.target, &abiType);
+    uint8_t* patchAt = codeBase + access.patchAt.offset();
+    Assembler::PatchDataWithValueCheck(CodeLocationLabel(patchAt),
+                                       PatchedImmPtr(target),
+                                       PatchedImmPtr((void*)-1));
+  }
+#else
+  MOZ_ASSERT(masm.symbolicAccesses().empty());
+#endif
+}