| //===--- Timer.h - Shared timers for compilation phases ---------*- C++ -*-===// |
| // |
| // This source file is part of the Swift.org open source project |
| // |
| // Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors |
| // Licensed under Apache License v2.0 with Runtime Library Exception |
| // |
| // See https://swift.org/LICENSE.txt for license information |
| // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef SWIFT_BASIC_TIMER_H |
| #define SWIFT_BASIC_TIMER_H |
| |
| #include "swift/Basic/LLVM.h" |
| #include "llvm/ADT/Optional.h" |
| #include "llvm/Support/Timer.h" |
| |
| namespace swift { |
| /// A convenience class for declaring a timer that's part of the Swift |
| /// compilation timers group. |
| /// |
| /// Please don't use this class directly for anything other than the flat, |
| /// top-level compilation-phase timing numbers; unadorned SharedTimers are |
| /// enabled, summed and reported via -debug-time-compilation, using LLVM's |
| /// built-in logic for timer groups, and that logic doesn't work right if |
| /// there's any nesting or reentry in timers at all (crashes on reentry, |
| /// simply mis-reports nesting). Additional SharedTimers also confuse users |
| /// who are expecting to see only top-level phase timings when they pass |
| /// -debug-time-compilation. |
| /// |
| /// Instead, please use FrontendStatsTracer objects and the -stats-output-dir |
| /// subsystem in include/swift/Basic/Statistic.h. In addition to not |
| /// interfering with users passing -debug-time-compilation, the |
| /// FrontendStatsTracer objects automatically instantiate nesting-safe and |
| /// reentry-safe SharedTimers themselves, as well as supporting event and |
| /// source-entity tracing and profiling. |
| class SharedTimer { |
| enum class State { |
| Initial, |
| Skipped, |
| Enabled |
| }; |
| static State CompilationTimersEnabled; |
| |
| Optional<llvm::NamedRegionTimer> Timer; |
| |
| public: |
| explicit SharedTimer(StringRef name) { |
| if (CompilationTimersEnabled == State::Enabled) |
| Timer.emplace(name, name, "swift", "Swift compilation"); |
| else |
| CompilationTimersEnabled = State::Skipped; |
| } |
| |
| /// Must be called before any SharedTimers have been created. |
| static void enableCompilationTimers() { |
| assert(CompilationTimersEnabled != State::Skipped && |
| "a timer has already been created"); |
| CompilationTimersEnabled = State::Enabled; |
| } |
| }; |
| } // end namespace swift |
| |
| #endif // SWIFT_BASIC_TIMER_H |