diff --git a/llvm/tools/llvm-xray/xray-account.cc b/llvm/tools/llvm-xray/xray-account.cc
diff --git a/llvm/tools/llvm-xray/xray-account.h b/llvm/tools/llvm-xray/xray-account.h
@@ -0,0 +1,104 @@
+//===- xray-account.h - XRay Function Call Accounting ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines the interface for performing some basic function call
+// accounting from an XRay trace.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_TOOLS_LLVM_XRAY_XRAY_ACCOUNT_H
+#define LLVM_TOOLS_LLVM_XRAY_XRAY_ACCOUNT_H
+
+#include <map>
+#include <utility>
+#include <vector>
+
+#include "func-id-helper.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/XRay/XRayRecord.h"
+
+namespace llvm {
+namespace xray {
+
+class LatencyAccountant {
+public:
+  typedef std::map<int32_t, std::vector<uint64_t>> FunctionLatencyMap;
+  typedef std::map<pid_t, std::pair<uint64_t, uint64_t>> PerThreadMinMaxTSCMap;
+  typedef std::map<uint8_t, std::pair<uint64_t, uint64_t>> PerCPUMinMaxTSCMap;
+  typedef std::vector<std::pair<int32_t, uint64_t>> FunctionStack;
+  typedef std::map<pid_t, FunctionStack> PerThreadFunctionStackMap;
+
+private:
+  PerThreadFunctionStackMap PerThreadFunctionStack;
+  FunctionLatencyMap FunctionLatencies;
+  PerThreadMinMaxTSCMap PerThreadMinMaxTSC;
+  PerCPUMinMaxTSCMap PerCPUMinMaxTSC;
+  FuncIdConversionHelper &FuncIdHelper;
+
+  bool DeduceSiblingCalls = false;
+  uint64_t CurrentMaxTSC = 0;
+
+  void recordLatency(int32_t FuncId, uint64_t Latency) {
+    FunctionLatencies[FuncId].push_back(Latency);
+  }
+
+public:
+  explicit LatencyAccountant(FuncIdConversionHelper &FuncIdHelper,
+                             bool DeduceSiblingCalls)
+      : FuncIdHelper(FuncIdHelper), DeduceSiblingCalls(DeduceSiblingCalls) {}
+
+  const FunctionLatencyMap &getFunctionLatencies() const {
+    return FunctionLatencies;
+  }
+
+  const PerThreadMinMaxTSCMap &getPerThreadMinMaxTSC() const {
+    return PerThreadMinMaxTSC;
+  }
+
+  const PerCPUMinMaxTSCMap &getPerCPUMinMaxTSC() const {
+    return PerCPUMinMaxTSC;
+  }
+
+  /// Returns false in case we fail to account the provided record. This happens
+  /// in the following cases:
+  ///
+  ///   - An exit record does not match any entry records for the same function.
+  ///     If we've been set to deduce sibling calls, we try walking up the stack
+  ///     and recording times for the higher level functions.
+  ///   - A record has a TSC that's before the latest TSC that has been
+  ///     recorded. We still record the TSC for the min-max.
+  ///
+  bool accountRecord(const XRayRecord &Record);
+
+  const FunctionStack *getThreadFunctionStack(pid_t TId) const {
+    auto I = PerThreadFunctionStack.find(TId);
+    if (I == PerThreadFunctionStack.end())
+      return nullptr;
+    return &I->second;
+  }
+
+  const PerThreadFunctionStackMap &getPerThreadFunctionStack() const {
+    return PerThreadFunctionStack;
+  }
+
+  // Output Functions
+  // ================
+
+  void exportStatsAsText(raw_ostream &OS, const XRayFileHeader &Header) const;
+  void exportStatsAsCSV(raw_ostream &OS, const XRayFileHeader &Header) const;
+
+private:
+  // Internal helper to implement common parts of the exportStatsAs...
+  // functions.
+  template <class F> void exportStats(const XRayFileHeader &Header, F fn) const;
+};
+
+} // namespace xray
+} // namespace llvm
+
+#endif // LLVM_TOOLS_LLVM_XRAY_XRAY_ACCOUNT_H
diff --git a/llvm/tools/llvm-xray/xray-record-yaml.h b/llvm/tools/llvm-xray/xray-record-yaml.h
@@ -0,0 +1,102 @@
+//===- xray-record-yaml.h - XRay Record YAML Support Definitions ----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Types and traits specialisations for YAML I/O of XRay log entries.
+//
+//===----------------------------------------------------------------------===//
+#ifndef LLVM_TOOLS_LLVM_XRAY_XRAY_RECORD_YAML_H
+#define LLVM_TOOLS_LLVM_XRAY_XRAY_RECORD_YAML_H
+
+#include <type_traits>
+
+#include "xray-record.h"
+#include "llvm/Support/YAMLTraits.h"
+
+namespace llvm {
+namespace xray {
+
+struct YAMLXRayFileHeader {
+  uint16_t Version;
+  uint16_t Type;
+  bool ConstantTSC;
+  bool NonstopTSC;
+  uint64_t CycleFrequency;
+};
+
+struct YAMLXRayRecord {
+  uint16_t RecordType;
+  uint8_t CPU;
+  RecordTypes Type;
+  int32_t FuncId;
+  std::string Function;
+  uint64_t TSC;
+  uint32_t TId;
+};
+
+struct YAMLXRayTrace {
+  YAMLXRayFileHeader Header;
+  std::vector<YAMLXRayRecord> Records;
+};
+
+using XRayRecordStorage =
+    std::aligned_storage<sizeof(XRayRecord), alignof(XRayRecord)>::type;
+
+} // namespace xray
+
+namespace yaml {
+
+// YAML Traits
+// -----------
+template <> struct ScalarEnumerationTraits<xray::RecordTypes> {
+  static void enumeration(IO &IO, xray::RecordTypes &Type) {
+    IO.enumCase(Type, "function-enter", xray::RecordTypes::ENTER);
+    IO.enumCase(Type, "function-exit", xray::RecordTypes::EXIT);
+  }
+};
+
+template <> struct MappingTraits<xray::YAMLXRayFileHeader> {
+  static void mapping(IO &IO, xray::YAMLXRayFileHeader &Header) {
+    IO.mapRequired("version", Header.Version);
+    IO.mapRequired("type", Header.Type);
+    IO.mapRequired("constant-tsc", Header.ConstantTSC);
+    IO.mapRequired("nonstop-tsc", Header.NonstopTSC);
+    IO.mapRequired("cycle-frequency", Header.CycleFrequency);
+  }
+};
+
+template <> struct MappingTraits<xray::YAMLXRayRecord> {
+  static void mapping(IO &IO, xray::YAMLXRayRecord &Record) {
+    // FIXME: Make this type actually be descriptive
+    IO.mapRequired("type", Record.RecordType);
+    IO.mapRequired("func-id", Record.FuncId);
+    IO.mapOptional("function", Record.Function);
+    IO.mapRequired("cpu", Record.CPU);
+    IO.mapRequired("thread", Record.TId);
+    IO.mapRequired("kind", Record.Type);
+    IO.mapRequired("tsc", Record.TSC);
+  }
+
+  static constexpr bool flow = true;
+};
+
+template <> struct MappingTraits<xray::YAMLXRayTrace> {
+  static void mapping(IO &IO, xray::YAMLXRayTrace &Trace) {
+    // A trace file contains two parts, the header and the list of all the
+    // trace records.
+    IO.mapRequired("header", Trace.Header);
+    IO.mapRequired("records", Trace.Records);
+  }
+};
+
+} // namespace yaml
+} // namespace llvm
+
+LLVM_YAML_IS_SEQUENCE_VECTOR(xray::YAMLXRayRecord) 
+
+#endif // LLVM_TOOLS_LLVM_XRAY_XRAY_RECORD_YAML_H