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      1 //===- Trace.h - XRay Trace Abstraction -----------------------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // Defines the XRay Trace class representing records in an XRay trace file.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 #ifndef LLVM_XRAY_TRACE_H
     14 #define LLVM_XRAY_TRACE_H
     15 
     16 #include <cstdint>
     17 #include <vector>
     18 
     19 #include "llvm/ADT/StringRef.h"
     20 #include "llvm/Support/Error.h"
     21 #include "llvm/Support/FileSystem.h"
     22 #include "llvm/XRay/XRayRecord.h"
     23 
     24 namespace llvm {
     25 namespace xray {
     26 
     27 /// A Trace object represents the records that have been loaded from XRay
     28 /// log files generated by instrumented binaries. We encapsulate the logic of
     29 /// reading the traces in factory functions that populate the Trace object
     30 /// appropriately.
     31 ///
     32 /// Trace objects provide an accessor to an XRayFileHeader which says more about
     33 /// details of the file from which the XRay trace was loaded from.
     34 ///
     35 /// Usage:
     36 ///
     37 ///   if (auto TraceOrErr = loadTraceFile("xray-log.something.xray")) {
     38 ///     auto& T = *TraceOrErr;
     39 ///     // T.getFileHeader() will provide information from the trace header.
     40 ///     for (const XRayRecord &R : T) {
     41 ///       // ... do something with R here.
     42 ///     }
     43 ///   } else {
     44 ///     // Handle the error here.
     45 ///   }
     46 ///
     47 class Trace {
     48   XRayFileHeader FileHeader;
     49   std::vector<XRayRecord> Records;
     50 
     51   typedef std::vector<XRayRecord>::const_iterator citerator;
     52 
     53   friend Expected<Trace> loadTraceFile(StringRef, bool);
     54 
     55 public:
     56   /// Provides access to the loaded XRay trace file header.
     57   const XRayFileHeader &getFileHeader() const { return FileHeader; }
     58 
     59   citerator begin() const { return Records.begin(); }
     60   citerator end() const { return Records.end(); }
     61   size_t size() const { return Records.size(); }
     62 };
     63 
     64 /// This function will attempt to load XRay trace records from the provided
     65 /// |Filename|.
     66 Expected<Trace> loadTraceFile(StringRef Filename, bool Sort = false);
     67 
     68 } // namespace xray
     69 } // namespace llvm
     70 
     71 #endif // LLVM_XRAY_TRACE_H
     72