forked from OSchip/llvm-project
80 lines
2.7 KiB
C++
80 lines
2.7 KiB
C++
//===--- Trace.h - Performance tracing facilities ---------------*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Supports writing performance traces describing clangd's behavior.
|
|
// Traces are written in the Trace Event format supported by chrome's trace
|
|
// viewer (chrome://tracing).
|
|
//
|
|
// The format is documented here:
|
|
// https://docs.google.com/document/d/1CvAClvFfyA5R-PhYUmn5OOQtYMH4h6I0nSsKchNAySU/preview
|
|
//
|
|
// All APIs are no-ops unless a Session is active (created by ClangdMain).
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_TRACE_H_
|
|
#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_TRACE_H_
|
|
|
|
#include "JSONExpr.h"
|
|
#include "llvm/ADT/Twine.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
|
|
namespace clang {
|
|
namespace clangd {
|
|
namespace trace {
|
|
|
|
// A session directs the output of trace events. Only one Session can exist.
|
|
// It should be created before clangd threads are spawned, and destroyed after
|
|
// they exit.
|
|
// TODO: we may want to add pluggable support for other tracing backends.
|
|
class Session {
|
|
public:
|
|
// Starts a sessions capturing trace events and writing Trace Event JSON.
|
|
static std::unique_ptr<Session> create(llvm::raw_ostream &OS,
|
|
bool Pretty = false);
|
|
~Session();
|
|
|
|
private:
|
|
Session() = default;
|
|
};
|
|
|
|
// Records a single instant event, associated with the current thread.
|
|
void log(const llvm::Twine &Name);
|
|
|
|
// Records an event whose duration is the lifetime of the Span object.
|
|
//
|
|
// Arbitrary JSON metadata can be attached while this span is active:
|
|
// SPAN_ATTACH(MySpan, "Payload", SomeJSONExpr);
|
|
// SomeJSONExpr is evaluated and copied only if actually needed.
|
|
class Span {
|
|
public:
|
|
Span(std::string Name);
|
|
~Span();
|
|
|
|
// Returns mutable span metadata if this span is interested.
|
|
// Prefer to use SPAN_ATTACH rather than accessing this directly.
|
|
json::obj *args() { return Args.get(); }
|
|
|
|
private:
|
|
std::unique_ptr<json::obj> Args;
|
|
};
|
|
|
|
#define SPAN_ATTACH(S, Name, Expr) \
|
|
do { \
|
|
if ((S).args() != nullptr) { \
|
|
(*((S).args()))[(Name)] = (Expr); \
|
|
} \
|
|
} while (0)
|
|
|
|
} // namespace trace
|
|
} // namespace clangd
|
|
} // namespace clang
|
|
|
|
#endif // LLVM_CLANG_TOOLS_EXTRA_CLANGD_TRACE_H_
|