[XRay] Implement the `llvm-xray account` subcommand

Summary:
This is the third of a multi-part change to implement subcommands for
the `llvm-xray` tool.

Here we define the `account` subcommand which does simple function call
accounting, generating basic statistics on function calls we find in an
XRay log/trace. We support text output and csv output for this
subcommand.

This change also supports sorting, summing, and filtering the top N
results.

Part of this tool will later be turned into a library that could be used
for basic function call accounting.

Depends on D24376.

Reviewers: dblaikie, echristo

Subscribers: mehdi_amini, dberris, beanz, llvm-commits

Differential Revision: https://reviews.llvm.org/D24377

llvm-svn: 291749

1 files changed, 104 insertions, 0 deletions

diff --git a/llvm/tools/llvm-xray/xray-account.h b/llvm/tools/llvm-xray/xray-account.h
new file mode 100644
index 00000000000..763ea011de0
--- /dev/null
+++ 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