[llvm] [llvm]Add a simple Telemetry framework (PR #102323)

[Thorsten Schütt via llvm-commits]

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@@ -0,0 +1,107 @@
+//===- llvm/Telemetry/Telemetry.h - Telemetry -------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TELEMETRY_TELEMETRY_H
+#define LLVM_TELEMETRY_TELEMETRY_H
+
+#include <chrono>
+#include <ctime>
+#include <memory>
+#include <optional>
+#include <string>
+
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/JSON.h"
+
+namespace llvm {
+namespace telemetry {
+
+using SteadyTimePoint = std::chrono::time_point<std::chrono::steady_clock>;
+
+struct TelemetryConfig {
+  // If true, telemetry will be enabled.
+  bool enable_telemetry;
+
+  // Additional destinations to send the logged entries.
+  // Could be stdout, stderr, or some local paths.
+  // Note: these are destinations are __in addition to__ whatever the default
+  // destination(s) are, as implemented by vendors.
+  std::vector<std::string> additional_destinations;
+};
+
+struct TelemetryEventStats {
+  // REQUIRED: Start time of event
+  SteadyTimePoint m_start;
+  // OPTIONAL: End time of event - may be empty if not meaningful.
+  std::optional<SteadyTimePoint> m_end;
+  // TBD: could add some memory stats here too?
+
+  TelemetryEventStats() = default;
+  TelemetryEventStats(SteadyTimePoint start) : m_start(start) {}
+  TelemetryEventStats(SteadyTimePoint start, SteadyTimePoint end)
+      : m_start(start), m_end(end) {}
+
+  std::string ToString() const;
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tschuett wrote:

I would call it a `Consumer` base class to avoid the connection to serialization.

https://github.com/llvm/llvm-project/pull/102323