1 files changed, 176 insertions, 0 deletions
diff --git a/js/src/wasm/WasmDebugFrame.cpp b/js/src/wasm/WasmDebugFrame.cpp
new file mode 100644
index 0000000000..2c93e750bc
--- /dev/null
+++ b/js/src/wasm/WasmDebugFrame.cpp
@@ -0,0 +1,176 @@
+/* -*- 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 2021 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/WasmDebugFrame.h"
+
+#include "vm/EnvironmentObject.h"
+#include "wasm/WasmBaselineCompile.h"
+#include "wasm/WasmDebug.h"
+#include "wasm/WasmInstance.h"
+#include "wasm/WasmInstanceData.h"
+#include "wasm/WasmStubs.h"
+
+#include "vm/NativeObject-inl.h"
+#include "wasm/WasmInstance-inl.h"
+
+using namespace js;
+using namespace js::jit;
+using namespace js::wasm;
+
+/* static */
+DebugFrame* DebugFrame::from(Frame* fp) {
+  MOZ_ASSERT(GetNearestEffectiveInstance(fp)->code().metadata().debugEnabled);
+  auto* df =
+      reinterpret_cast<DebugFrame*>((uint8_t*)fp - DebugFrame::offsetOfFrame());
+  MOZ_ASSERT(GetNearestEffectiveInstance(fp) == df->instance());
+  return df;
+}
+
+void DebugFrame::alignmentStaticAsserts() {
+  // VS2017 doesn't consider offsetOfFrame() to be a constexpr, so we have
+  // to use offsetof directly. These asserts can't be at class-level
+  // because the type is incomplete.
+
+  static_assert(WasmStackAlignment >= Alignment,
+                "Aligned by ABI before pushing DebugFrame");
+#ifndef JS_CODEGEN_NONE
+  static_assert((offsetof(DebugFrame, frame_) + sizeof(Frame)) % Alignment == 0,
+                "Aligned after pushing DebugFrame");
+#endif
+#ifdef JS_CODEGEN_ARM64
+  // This constraint may or may not be necessary.  If you hit this because
+  // you've changed the frame size then feel free to remove it, but be extra
+  // aware of possible problems.
+  static_assert(sizeof(DebugFrame) % 16 == 0, "ARM64 SP alignment");
+#endif
+}
+
+Instance* DebugFrame::instance() {
+  return GetNearestEffectiveInstance(&frame_);
+}
+
+const Instance* DebugFrame::instance() const {
+  return GetNearestEffectiveInstance(&frame_);
+}
+
+GlobalObject* DebugFrame::global() { return &instance()->object()->global(); }
+
+bool DebugFrame::hasGlobal(const GlobalObject* global) const {
+  return global == &instance()->objectUnbarriered()->global();
+}
+
+JSObject* DebugFrame::environmentChain() {
+  return &global()->lexicalEnvironment();
+}
+
+bool DebugFrame::getLocal(uint32_t localIndex, MutableHandleValue vp) {
+  ValTypeVector locals;
+  size_t argsLength;
+  StackResults stackResults;
+  if (!instance()->debug().debugGetLocalTypes(funcIndex(), &locals, &argsLength,
+                                              &stackResults)) {
+    return false;
+  }
+
+  ValTypeVector args;
+  MOZ_ASSERT(argsLength <= locals.length());
+  if (!args.append(locals.begin(), argsLength)) {
+    return false;
+  }
+  ArgTypeVector abiArgs(args, stackResults);
+
+  BaseLocalIter iter(locals, abiArgs, /* debugEnabled = */ true);
+  while (!iter.done() && iter.index() < localIndex) {
+    iter++;
+  }
+  MOZ_ALWAYS_TRUE(!iter.done());
+
+  uint8_t* frame = static_cast<uint8_t*>((void*)this) + offsetOfFrame();
+  void* dataPtr = frame - iter.frameOffset();
+  switch (iter.mirType()) {
+    case jit::MIRType::Int32:
+      vp.set(Int32Value(*static_cast<int32_t*>(dataPtr)));
+      break;
+    case jit::MIRType::Int64:
+      // Just display as a Number; it's ok if we lose some precision
+      vp.set(NumberValue((double)*static_cast<int64_t*>(dataPtr)));
+      break;
+    case jit::MIRType::Float32:
+      vp.set(NumberValue(JS::CanonicalizeNaN(*static_cast<float*>(dataPtr))));
+      break;
+    case jit::MIRType::Double:
+      vp.set(NumberValue(JS::CanonicalizeNaN(*static_cast<double*>(dataPtr))));
+      break;
+    case jit::MIRType::RefOrNull:
+      vp.set(ObjectOrNullValue(*(JSObject**)dataPtr));
+      break;
+#ifdef ENABLE_WASM_SIMD
+    case jit::MIRType::Simd128:
+      vp.set(NumberValue(0));
+      break;
+#endif
+    default:
+      MOZ_CRASH("local type");
+  }
+  return true;
+}
+
+bool DebugFrame::updateReturnJSValue(JSContext* cx) {
+  MutableHandleValue rval =
+      MutableHandleValue::fromMarkedLocation(&cachedReturnJSValue_);
+  rval.setUndefined();
+  flags_.hasCachedReturnJSValue = true;
+  ResultType resultType = ResultType::Vector(
+      instance()->metadata().debugFuncType(funcIndex()).results());
+  Maybe<char*> stackResultsLoc;
+  if (ABIResultIter::HasStackResults(resultType)) {
+    stackResultsLoc = Some(static_cast<char*>(stackResultsPointer_));
+  }
+  DebugCodegen(DebugChannel::Function,
+               "wasm-function[%d] updateReturnJSValue [", funcIndex());
+  bool ok =
+      ResultsToJSValue(cx, resultType, registerResults_, stackResultsLoc, rval);
+  DebugCodegen(DebugChannel::Function, "]\n");
+  return ok;
+}
+
+HandleValue DebugFrame::returnValue() const {
+  MOZ_ASSERT(flags_.hasCachedReturnJSValue);
+  return HandleValue::fromMarkedLocation(&cachedReturnJSValue_);
+}
+
+void DebugFrame::clearReturnJSValue() {
+  flags_.hasCachedReturnJSValue = true;
+  cachedReturnJSValue_.setUndefined();
+}
+
+void DebugFrame::observe(JSContext* cx) {
+  if (!flags_.observing) {
+    instance()->debug().adjustEnterAndLeaveFrameTrapsState(
+        cx, instance(), /* enabled = */ true);
+    flags_.observing = true;
+  }
+}
+
+void DebugFrame::leave(JSContext* cx) {
+  if (flags_.observing) {
+    instance()->debug().adjustEnterAndLeaveFrameTrapsState(
+        cx, instance(), /* enabled = */ false);
+    flags_.observing = false;
+  }
+}