1 files changed, 188 insertions, 0 deletions
diff --git a/toolkit/components/telemetry/other/ProcessedStack.cpp b/toolkit/components/telemetry/other/ProcessedStack.cpp
new file mode 100644
index 0000000000..ce62826a05
--- /dev/null
+++ b/toolkit/components/telemetry/other/ProcessedStack.cpp
@@ -0,0 +1,188 @@
+/* -*- 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 "ProcessedStack.h"
+
+namespace {
+
+struct StackFrame {
+  uintptr_t mPC;    // The program counter at this position in the call stack.
+  uint16_t mIndex;  // The number of this frame in the call stack.
+  uint16_t mModIndex;  // The index of module that has this program counter.
+};
+
+#ifdef MOZ_GECKO_PROFILER
+static bool CompareByPC(const StackFrame& a, const StackFrame& b) {
+  return a.mPC < b.mPC;
+}
+
+static bool CompareByIndex(const StackFrame& a, const StackFrame& b) {
+  return a.mIndex < b.mIndex;
+}
+#endif
+
+}  // namespace
+
+namespace mozilla::Telemetry {
+
+const size_t kMaxChromeStackDepth = 50;
+
+ProcessedStack::ProcessedStack() = default;
+
+size_t ProcessedStack::GetStackSize() const { return mStack.size(); }
+
+size_t ProcessedStack::GetNumModules() const { return mModules.size(); }
+
+bool ProcessedStack::Module::operator==(const Module& aOther) const {
+  return mName == aOther.mName && mBreakpadId == aOther.mBreakpadId;
+}
+
+const ProcessedStack::Frame& ProcessedStack::GetFrame(unsigned aIndex) const {
+  MOZ_ASSERT(aIndex < mStack.size());
+  return mStack[aIndex];
+}
+
+void ProcessedStack::AddFrame(const Frame& aFrame) { mStack.push_back(aFrame); }
+
+const ProcessedStack::Module& ProcessedStack::GetModule(unsigned aIndex) const {
+  MOZ_ASSERT(aIndex < mModules.size());
+  return mModules[aIndex];
+}
+
+void ProcessedStack::AddModule(const Module& aModule) {
+  mModules.push_back(aModule);
+}
+
+void ProcessedStack::Clear() {
+  mModules.clear();
+  mStack.clear();
+}
+
+ProcessedStack GetStackAndModules(const std::vector<uintptr_t>& aPCs) {
+  return BatchProcessedStackGenerator().GetStackAndModules(aPCs);
+}
+
+BatchProcessedStackGenerator::BatchProcessedStackGenerator()
+#ifdef MOZ_GECKO_PROFILER
+    : mSortedRawModules(SharedLibraryInfo::GetInfoForSelf())
+#endif
+{
+#ifdef MOZ_GECKO_PROFILER
+  mSortedRawModules.SortByAddress();
+#endif
+}
+
+#ifndef MOZ_GECKO_PROFILER
+static ProcessedStack GetStackAndModulesInternal(
+    std::vector<StackFrame>& aRawStack) {
+#else
+static ProcessedStack GetStackAndModulesInternal(
+    std::vector<StackFrame>& aRawStack, SharedLibraryInfo& aSortedRawModules) {
+  SharedLibraryInfo rawModules(aSortedRawModules);
+  // Remove all modules not referenced by a PC on the stack
+  std::sort(aRawStack.begin(), aRawStack.end(), CompareByPC);
+
+  size_t moduleIndex = 0;
+  size_t stackIndex = 0;
+  size_t stackSize = aRawStack.size();
+
+  while (moduleIndex < rawModules.GetSize()) {
+    const SharedLibrary& module = rawModules.GetEntry(moduleIndex);
+    uintptr_t moduleStart = module.GetStart();
+    uintptr_t moduleEnd = module.GetEnd() - 1;
+    // the interval is [moduleStart, moduleEnd)
+
+    bool moduleReferenced = false;
+    for (; stackIndex < stackSize; ++stackIndex) {
+      uintptr_t pc = aRawStack[stackIndex].mPC;
+      if (pc >= moduleEnd) break;
+
+      if (pc >= moduleStart) {
+        // If the current PC is within the current module, mark
+        // module as used
+        moduleReferenced = true;
+        aRawStack[stackIndex].mPC -= moduleStart;
+        aRawStack[stackIndex].mModIndex = moduleIndex;
+      } else {
+        // PC does not belong to any module. It is probably from
+        // the JIT. Use a fixed mPC so that we don't get different
+        // stacks on different runs.
+        aRawStack[stackIndex].mPC = std::numeric_limits<uintptr_t>::max();
+      }
+    }
+
+    if (moduleReferenced) {
+      ++moduleIndex;
+    } else {
+      // Remove module if no PCs within its address range
+      rawModules.RemoveEntries(moduleIndex, moduleIndex + 1);
+    }
+  }
+
+  for (; stackIndex < stackSize; ++stackIndex) {
+    // These PCs are past the last module.
+    aRawStack[stackIndex].mPC = std::numeric_limits<uintptr_t>::max();
+  }
+
+  std::sort(aRawStack.begin(), aRawStack.end(), CompareByIndex);
+#endif
+
+  // Copy the information to the return value.
+  ProcessedStack Ret;
+  for (auto& rawFrame : aRawStack) {
+    mozilla::Telemetry::ProcessedStack::Frame frame = {rawFrame.mPC,
+                                                       rawFrame.mModIndex};
+    Ret.AddFrame(frame);
+  }
+
+#ifdef MOZ_GECKO_PROFILER
+  for (unsigned i = 0, n = rawModules.GetSize(); i != n; ++i) {
+    const SharedLibrary& info = rawModules.GetEntry(i);
+    mozilla::Telemetry::ProcessedStack::Module module = {info.GetDebugName(),
+                                                         info.GetBreakpadId()};
+    Ret.AddModule(module);
+  }
+#endif
+
+  return Ret;
+}
+
+ProcessedStack BatchProcessedStackGenerator::GetStackAndModules(
+    const std::vector<uintptr_t>& aPCs) {
+  std::vector<StackFrame> rawStack;
+  auto stackEnd = aPCs.begin() + std::min(aPCs.size(), kMaxChromeStackDepth);
+  for (auto i = aPCs.begin(); i != stackEnd; ++i) {
+    uintptr_t aPC = *i;
+    StackFrame Frame = {aPC, static_cast<uint16_t>(rawStack.size()),
+                        std::numeric_limits<uint16_t>::max()};
+    rawStack.push_back(Frame);
+  }
+
+#if defined(MOZ_GECKO_PROFILER)
+  return GetStackAndModulesInternal(rawStack, mSortedRawModules);
+#else
+  return GetStackAndModulesInternal(rawStack);
+#endif
+}
+
+ProcessedStack BatchProcessedStackGenerator::GetStackAndModules(
+    const uintptr_t* aBegin, const uintptr_t* aEnd) {
+  std::vector<StackFrame> rawStack;
+  for (auto i = aBegin; i != aEnd; ++i) {
+    uintptr_t aPC = *i;
+    StackFrame Frame = {aPC, static_cast<uint16_t>(rawStack.size()),
+                        std::numeric_limits<uint16_t>::max()};
+    rawStack.push_back(Frame);
+  }
+
+#if defined(MOZ_GECKO_PROFILER)
+  return GetStackAndModulesInternal(rawStack, mSortedRawModules);
+#else
+  return GetStackAndModulesInternal(rawStack);
+#endif
+}
+
+}  // namespace mozilla::Telemetry