1 files changed, 305 insertions, 0 deletions
diff --git a/js/src/frontend/FrontendContext.cpp b/js/src/frontend/FrontendContext.cpp
new file mode 100644
index 0000000000..aeb12efe93
--- /dev/null
+++ b/js/src/frontend/FrontendContext.cpp
@@ -0,0 +1,305 @@
+/* -*- 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 "frontend/FrontendContext.h"
+
+#ifdef _WIN32
+#  include <windows.h>
+#  include <process.h>  // GetCurrentThreadId
+#else
+#  include <pthread.h>  // pthread_self
+#endif
+
+#include "gc/GC.h"
+#include "js/AllocPolicy.h"  // js::ReportOutOfMemory
+#include "js/friend/StackLimits.h"  // js::ReportOverRecursed, js::MinimumStackLimitMargin
+#include "js/Modules.h"
+#include "util/DifferentialTesting.h"
+#include "util/NativeStack.h"  // GetNativeStackBase
+#include "vm/JSContext.h"
+
+using namespace js;
+
+void FrontendErrors::clearErrors() {
+  error.reset();
+  warnings.clear();
+  overRecursed = false;
+  outOfMemory = false;
+  allocationOverflow = false;
+}
+
+void FrontendErrors::clearWarnings() { warnings.clear(); }
+
+void FrontendAllocator::reportAllocationOverflow() {
+  fc_->onAllocationOverflow();
+}
+
+void* FrontendAllocator::onOutOfMemory(AllocFunction allocFunc,
+                                       arena_id_t arena, size_t nbytes,
+                                       void* reallocPtr) {
+  return fc_->onOutOfMemory(allocFunc, arena, nbytes, reallocPtr);
+}
+
+FrontendContext::~FrontendContext() {
+  if (ownNameCollectionPool_) {
+    MOZ_ASSERT(nameCollectionPool_);
+    js_delete(nameCollectionPool_);
+  }
+}
+
+void FrontendContext::setStackQuota(JS::NativeStackSize stackSize) {
+#ifdef __wasi__
+  stackLimit_ = JS::WASINativeStackLimit;
+#else   // __wasi__
+  if (stackSize == 0) {
+    stackLimit_ = JS::NativeStackLimitMax;
+  } else {
+    stackLimit_ = JS::GetNativeStackLimit(GetNativeStackBase(), stackSize - 1);
+  }
+#endif  // !__wasi__
+
+#ifdef DEBUG
+  setNativeStackLimitThread();
+#endif
+}
+
+bool FrontendContext::allocateOwnedPool() {
+  MOZ_ASSERT(!nameCollectionPool_);
+
+  nameCollectionPool_ = js_new<frontend::NameCollectionPool>();
+  if (!nameCollectionPool_) {
+    return false;
+  }
+  ownNameCollectionPool_ = true;
+  return true;
+}
+
+bool FrontendContext::hadErrors() const {
+  // All errors must be reported to FrontendContext.
+  MOZ_ASSERT_IF(maybeCx_, !maybeCx_->isExceptionPending());
+
+  return errors_.hadErrors();
+}
+
+void FrontendContext::clearErrors() {
+  MOZ_ASSERT(!maybeCx_);
+  return errors_.clearErrors();
+}
+
+void FrontendContext::clearWarnings() { return errors_.clearWarnings(); }
+
+void* FrontendContext::onOutOfMemory(AllocFunction allocFunc, arena_id_t arena,
+                                     size_t nbytes, void* reallocPtr) {
+  addPendingOutOfMemory();
+  return nullptr;
+}
+
+void FrontendContext::onAllocationOverflow() {
+  errors_.allocationOverflow = true;
+}
+
+void FrontendContext::onOutOfMemory() { addPendingOutOfMemory(); }
+
+void FrontendContext::onOverRecursed() { errors_.overRecursed = true; }
+
+void FrontendContext::recoverFromOutOfMemory() {
+  MOZ_ASSERT_IF(maybeCx_, !maybeCx_->isThrowingOutOfMemory());
+
+  errors_.outOfMemory = false;
+}
+
+const JSErrorFormatString* FrontendContext::gcSafeCallback(
+    JSErrorCallback callback, void* userRef, const unsigned errorNumber) {
+  mozilla::Maybe<gc::AutoSuppressGC> suppressGC;
+  if (maybeCx_) {
+    suppressGC.emplace(maybeCx_);
+  }
+
+  return callback(userRef, errorNumber);
+}
+
+void FrontendContext::reportError(CompileError&& err) {
+  if (errors_.error) {
+    errors_.error.reset();
+  }
+
+  // When compiling off thread, save the error so that the thread finishing the
+  // parse can report it later.
+  errors_.error.emplace(std::move(err));
+}
+
+bool FrontendContext::reportWarning(CompileError&& err) {
+  if (!errors_.warnings.append(std::move(err))) {
+    ReportOutOfMemory();
+    return false;
+  }
+
+  return true;
+}
+
+void FrontendContext::ReportOutOfMemory() {
+  /*
+   * OOMs are non-deterministic, especially across different execution modes
+   * (e.g. interpreter vs JIT). When doing differential testing, print to
+   * stderr so that the fuzzers can detect this.
+   */
+  if (SupportDifferentialTesting()) {
+    fprintf(stderr, "ReportOutOfMemory called\n");
+  }
+
+  addPendingOutOfMemory();
+}
+
+void FrontendContext::addPendingOutOfMemory() { errors_.outOfMemory = true; }
+
+void FrontendContext::setCurrentJSContext(JSContext* cx) {
+  MOZ_ASSERT(!nameCollectionPool_);
+
+  maybeCx_ = cx;
+  nameCollectionPool_ = &cx->frontendCollectionPool();
+  scriptDataTableHolder_ = &cx->runtime()->scriptDataTableHolder();
+  stackLimit_ = cx->stackLimitForCurrentPrincipal();
+
+#ifdef DEBUG
+  setNativeStackLimitThread();
+#endif
+}
+
+bool FrontendContext::convertToRuntimeError(
+    JSContext* cx, Warning warning /* = Warning::Report */) {
+  // Report out of memory errors eagerly, or errors could be malformed.
+  if (hadOutOfMemory()) {
+    js::ReportOutOfMemory(cx);
+    return false;
+  }
+
+  if (maybeError()) {
+    if (!maybeError()->throwError(cx)) {
+      return false;
+    }
+  }
+  if (warning == Warning::Report) {
+    for (CompileError& error : warnings()) {
+      if (!error.throwError(cx)) {
+        return false;
+      }
+    }
+  }
+  if (hadOverRecursed()) {
+    js::ReportOverRecursed(cx);
+  }
+  if (hadAllocationOverflow()) {
+    js::ReportAllocationOverflow(cx);
+  }
+
+  MOZ_ASSERT(!extraBindingsAreNotUsed(),
+             "extraBindingsAreNotUsed shouldn't escape from FrontendContext");
+  return true;
+}
+
+#ifdef DEBUG
+static size_t GetTid() {
+#  if defined(_WIN32)
+  return size_t(GetCurrentThreadId());
+#  else
+  return size_t(pthread_self());
+#  endif
+}
+
+void FrontendContext::setNativeStackLimitThread() {
+  stackLimitThreadId_.emplace(GetTid());
+}
+
+void FrontendContext::assertNativeStackLimitThread() {
+  if (!stackLimitThreadId_.isSome()) {
+    return;
+  }
+
+  MOZ_ASSERT(*stackLimitThreadId_ == GetTid());
+}
+#endif
+
+#ifdef __wasi__
+void FrontendContext::incWasiRecursionDepth() {
+  if (maybeCx_) {
+    IncWasiRecursionDepth(maybeCx_);
+  }
+}
+
+void FrontendContext::decWasiRecursionDepth() {
+  if (maybeCx_) {
+    DecWasiRecursionDepth(maybeCx_);
+  }
+}
+
+bool FrontendContext::checkWasiRecursionLimit() {
+  if (maybeCx_) {
+    return CheckWasiRecursionLimit(maybeCx_);
+  }
+  return true;
+}
+
+JS_PUBLIC_API void js::IncWasiRecursionDepth(FrontendContext* fc) {
+  fc->incWasiRecursionDepth();
+}
+
+JS_PUBLIC_API void js::DecWasiRecursionDepth(FrontendContext* fc) {
+  fc->decWasiRecursionDepth();
+}
+
+JS_PUBLIC_API bool js::CheckWasiRecursionLimit(FrontendContext* fc) {
+  return fc->checkWasiRecursionLimit();
+}
+#endif  // __wasi__
+
+FrontendContext* js::NewFrontendContext() {
+  UniquePtr<FrontendContext> fc = MakeUnique<FrontendContext>();
+  if (!fc) {
+    return nullptr;
+  }
+
+  if (!fc->allocateOwnedPool()) {
+    return nullptr;
+  }
+
+  return fc.release();
+}
+
+void js::DestroyFrontendContext(FrontendContext* fc) { js_delete_poison(fc); }
+
+#ifdef DEBUG
+void FrontendContext::checkAndUpdateFrontendContextRecursionLimit(void* sp) {
+  // For the js::MinimumStackLimitMargin to be effective, it should be larger
+  // than the largest stack space which might be consumed by successive calls
+  // to AutoCheckRecursionLimit::check.
+  //
+  // This function asserts that this property holds by recalling the stack
+  // pointer of the previous call and comparing the consumed stack size with
+  // the minimum margin.
+  //
+  // If this property does not hold, either the stack limit should be increased
+  // or more calls to check for recursion should be added.
+  if (previousStackPointer_ != nullptr) {
+#  if JS_STACK_GROWTH_DIRECTION > 0
+    if (sp > previousStackPointer_) {
+      size_t diff = uintptr_t(sp) - uintptr_t(previousStackPointer_);
+      MOZ_ASSERT(diff < js::MinimumStackLimitMargin);
+    }
+#  else
+    if (sp < previousStackPointer_) {
+      size_t diff = uintptr_t(previousStackPointer_) - uintptr_t(sp);
+      MOZ_ASSERT(diff < js::MinimumStackLimitMargin);
+    }
+#  endif
+  }
+  previousStackPointer_ = sp;
+}
+
+void js::CheckAndUpdateFrontendContextRecursionLimit(FrontendContext* fc,
+                                                     void* sp) {
+  fc->checkAndUpdateFrontendContextRecursionLimit(sp);
+}
+#endif