Line data    Source code

       1             : //===- Profile.h - XRay Profile 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 Profile class representing the latency profile generated by
      11             : // XRay's profiling mode.
      12             : //
      13             : //===----------------------------------------------------------------------===//
      14             : #ifndef LLVM_XRAY_PROFILE_H
      15             : #define LLVM_XRAY_PROFILE_H
      16             : 
      17             : #include "llvm/ADT/DenseMap.h"
      18             : #include "llvm/ADT/SmallVector.h"
      19             : #include "llvm/ADT/StringRef.h"
      20             : #include "llvm/Support/Error.h"
      21             : #include <list>
      22             : #include <utility>
      23             : #include <vector>
      24             : 
      25             : namespace llvm {
      26             : namespace xray {
      27             : 
      28             : class Profile;
      29             : 
      30             : // We forward declare the Trace type for turning a Trace into a Profile.
      31             : class Trace;
      32             : 
      33             : /// This function will attempt to load an XRay Profiling Mode profile from the
      34             : /// provided |Filename|.
      35             : ///
      36             : /// For any errors encountered in the loading of the profile data from
      37             : /// |Filename|, this function will return an Error condition appropriately.
      38             : Expected<Profile> loadProfile(StringRef Filename);
      39             : 
      40             : /// This algorithm will merge two Profile instances into a single Profile
      41             : /// instance, aggregating blocks by Thread ID.
      42             : Profile mergeProfilesByThread(const Profile &L, const Profile &R);
      43             : 
      44             : /// This algorithm will merge two Profile instances into a single Profile
      45             : /// instance, aggregating blocks by function call stack.
      46             : Profile mergeProfilesByStack(const Profile &L, const Profile &R);
      47             : 
      48             : /// This function takes a Trace and creates a Profile instance from it.
      49             : Expected<Profile> profileFromTrace(const Trace &T);
      50             : 
      51             : /// Profile instances are thread-compatible.
      52             : class Profile {
      53             : public:
      54             :   using ThreadID = uint64_t;
      55             :   using PathID = unsigned;
      56             :   using FuncID = int32_t;
      57             : 
      58             :   struct Data {
      59             :     uint64_t CallCount;
      60             :     uint64_t CumulativeLocalTime;
      61             :   };
      62             : 
      63          27 :   struct Block {
      64             :     ThreadID Thread;
      65             :     std::vector<std::pair<PathID, Data>> PathData;
      66             :   };
      67             : 
      68             :   /// Provides a sequence of function IDs from a previously interned PathID.
      69             :   ///
      70             :   /// Returns an error if |P| had not been interned before into the Profile.
      71             :   ///
      72             :   Expected<std::vector<FuncID>> expandPath(PathID P) const;
      73             : 
      74             :   /// The stack represented in |P| must be in stack order (leaf to root). This
      75             :   /// will always return the same PathID for |P| that has the same sequence.
      76             :   PathID internPath(ArrayRef<FuncID> P);
      77             : 
      78             :   /// Appends a fully-formed Block instance into the Profile.
      79             :   ///
      80             :   /// Returns an error condition in the following cases:
      81             :   ///
      82             :   ///    - The PathData component of the Block is empty
      83             :   ///
      84             :   Error addBlock(Block &&B);
      85             : 
      86          22 :   Profile() = default;
      87          29 :   ~Profile() = default;
      88             : 
      89           2 :   Profile(Profile &&O) noexcept
      90           2 :       : Blocks(std::move(O.Blocks)), NodeStorage(std::move(O.NodeStorage)),
      91             :         Roots(std::move(O.Roots)), PathIDMap(std::move(O.PathIDMap)),
      92           2 :         NextID(O.NextID) {}
      93             : 
      94           7 :   Profile &operator=(Profile &&O) noexcept {
      95           7 :     Blocks = std::move(O.Blocks);
      96           7 :     NodeStorage = std::move(O.NodeStorage);
      97             :     Roots = std::move(O.Roots);
      98           7 :     PathIDMap = std::move(O.PathIDMap);
      99           7 :     NextID = O.NextID;
     100           7 :     return *this;
     101             :   }
     102             : 
     103             :   Profile(const Profile &);
     104             :   Profile &operator=(const Profile &);
     105             : 
     106             :   friend void swap(Profile &L, Profile &R) {
     107             :     using std::swap;
     108             :     swap(L.Blocks, R.Blocks);
     109             :     swap(L.NodeStorage, R.NodeStorage);
     110             :     swap(L.Roots, R.Roots);
     111             :     swap(L.PathIDMap, R.PathIDMap);
     112             :     swap(L.NextID, R.NextID);
     113             :   }
     114             : 
     115             : private:
     116             :   using BlockList = std::list<Block>;
     117             : 
     118          64 :   struct TrieNode {
     119             :     FuncID Func = 0;
     120             :     std::vector<TrieNode *> Callees{};
     121             :     TrieNode *Caller = nullptr;
     122             :     PathID ID = 0;
     123             :   };
     124             : 
     125             :   // List of blocks associated with a Profile.
     126             :   BlockList Blocks;
     127             : 
     128             :   // List of TrieNode elements we've seen.
     129             :   std::list<TrieNode> NodeStorage;
     130             : 
     131             :   // List of call stack roots.
     132             :   SmallVector<TrieNode *, 4> Roots;
     133             : 
     134             :   // Reverse mapping between a PathID to a TrieNode*.
     135             :   DenseMap<PathID, TrieNode *> PathIDMap;
     136             : 
     137             :   // Used to identify paths.
     138             :   PathID NextID = 1;
     139             : 
     140             : public:
     141             :   using const_iterator = BlockList::const_iterator;
     142          22 :   const_iterator begin() const { return Blocks.begin(); }
     143             :   const_iterator end() const { return Blocks.end(); }
     144             :   bool empty() const { return Blocks.empty(); }
     145             : };
     146             : 
     147             : } // namespace xray
     148             : } // namespace llvm
     149             : 
     150             : #endif