1 //===- llvm/Analysis/MemoryProfileInfo.h - memory profile info ---*- C++ -*-==// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file contains utilities to analyze memory profile information. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_ANALYSIS_MEMORYPROFILEINFO_H 14 #define LLVM_ANALYSIS_MEMORYPROFILEINFO_H 15 16 #include "llvm/IR/Constants.h" 17 #include "llvm/IR/InstrTypes.h" 18 #include "llvm/IR/Metadata.h" 19 #include "llvm/IR/Module.h" 20 #include "llvm/IR/ModuleSummaryIndex.h" 21 #include <map> 22 23 namespace llvm { 24 namespace memprof { 25 26 /// Return the allocation type for a given set of memory profile values. 27 AllocationType getAllocType(uint64_t TotalLifetimeAccessDensity, 28 uint64_t AllocCount, uint64_t TotalLifetime); 29 30 /// Build callstack metadata from the provided list of call stack ids. Returns 31 /// the resulting metadata node. 32 MDNode *buildCallstackMetadata(ArrayRef<uint64_t> CallStack, LLVMContext &Ctx); 33 34 /// Returns the stack node from an MIB metadata node. 35 MDNode *getMIBStackNode(const MDNode *MIB); 36 37 /// Returns the allocation type from an MIB metadata node. 38 AllocationType getMIBAllocType(const MDNode *MIB); 39 40 /// Returns the string to use in attributes with the given type. 41 std::string getAllocTypeAttributeString(AllocationType Type); 42 43 /// True if the AllocTypes bitmask contains just a single type. 44 bool hasSingleAllocType(uint8_t AllocTypes); 45 46 /// Class to build a trie of call stack contexts for a particular profiled 47 /// allocation call, along with their associated allocation types. 48 /// The allocation will be at the root of the trie, which is then used to 49 /// compute the minimum lists of context ids needed to associate a call context 50 /// with a single allocation type. 51 class CallStackTrie { 52 private: 53 struct CallStackTrieNode { 54 // Allocation types for call context sharing the context prefix at this 55 // node. 56 uint8_t AllocTypes; 57 // Map of caller stack id to the corresponding child Trie node. 58 std::map<uint64_t, CallStackTrieNode *> Callers; 59 CallStackTrieNode(AllocationType Type) 60 : AllocTypes(static_cast<uint8_t>(Type)) {} 61 }; 62 63 // The node for the allocation at the root. 64 CallStackTrieNode *Alloc = nullptr; 65 // The allocation's leaf stack id. 66 uint64_t AllocStackId = 0; 67 68 void deleteTrieNode(CallStackTrieNode *Node) { 69 if (!Node) 70 return; 71 for (auto C : Node->Callers) 72 deleteTrieNode(C.second); 73 delete Node; 74 } 75 76 // Recursive helper to trim contexts and create metadata nodes. 77 bool buildMIBNodes(CallStackTrieNode *Node, LLVMContext &Ctx, 78 std::vector<uint64_t> &MIBCallStack, 79 std::vector<Metadata *> &MIBNodes, 80 bool CalleeHasAmbiguousCallerContext); 81 82 public: 83 CallStackTrie() = default; 84 ~CallStackTrie() { deleteTrieNode(Alloc); } 85 86 bool empty() const { return Alloc == nullptr; } 87 88 /// Add a call stack context with the given allocation type to the Trie. 89 /// The context is represented by the list of stack ids (computed during 90 /// matching via a debug location hash), expected to be in order from the 91 /// allocation call down to the bottom of the call stack (i.e. callee to 92 /// caller order). 93 void addCallStack(AllocationType AllocType, ArrayRef<uint64_t> StackIds); 94 95 /// Add the call stack context along with its allocation type from the MIB 96 /// metadata to the Trie. 97 void addCallStack(MDNode *MIB); 98 99 /// Build and attach the minimal necessary MIB metadata. If the alloc has a 100 /// single allocation type, add a function attribute instead. The reason for 101 /// adding an attribute in this case is that it matches how the behavior for 102 /// allocation calls will be communicated to lib call simplification after 103 /// cloning or another optimization to distinguish the allocation types, 104 /// which is lower overhead and more direct than maintaining this metadata. 105 /// Returns true if memprof metadata attached, false if not (attribute added). 106 bool buildAndAttachMIBMetadata(CallBase *CI); 107 }; 108 109 /// Helper class to iterate through stack ids in both metadata (memprof MIB and 110 /// callsite) and the corresponding ThinLTO summary data structures 111 /// (CallsiteInfo and MIBInfo). This simplifies implementation of client code 112 /// which doesn't need to worry about whether we are operating with IR (Regular 113 /// LTO), or summary (ThinLTO). 114 template <class NodeT, class IteratorT> class CallStack { 115 public: 116 CallStack(const NodeT *N = nullptr) : N(N) {} 117 118 // Implement minimum required methods for range-based for loop. 119 // The default implementation assumes we are operating on ThinLTO data 120 // structures, which have a vector of StackIdIndices. There are specialized 121 // versions provided to iterate through metadata. 122 struct CallStackIterator { 123 const NodeT *N = nullptr; 124 IteratorT Iter; 125 CallStackIterator(const NodeT *N, bool End); 126 uint64_t operator*(); 127 bool operator==(const CallStackIterator &rhs) { return Iter == rhs.Iter; } 128 bool operator!=(const CallStackIterator &rhs) { return !(*this == rhs); } 129 void operator++() { ++Iter; } 130 }; 131 132 bool empty() const { return N == nullptr; } 133 134 CallStackIterator begin() const; 135 CallStackIterator end() const { return CallStackIterator(N, /*End*/ true); } 136 CallStackIterator beginAfterSharedPrefix(CallStack &Other); 137 uint64_t back() const; 138 139 private: 140 const NodeT *N = nullptr; 141 }; 142 143 template <class NodeT, class IteratorT> 144 CallStack<NodeT, IteratorT>::CallStackIterator::CallStackIterator( 145 const NodeT *N, bool End) 146 : N(N) { 147 if (!N) { 148 Iter = nullptr; 149 return; 150 } 151 Iter = End ? N->StackIdIndices.end() : N->StackIdIndices.begin(); 152 } 153 154 template <class NodeT, class IteratorT> 155 uint64_t CallStack<NodeT, IteratorT>::CallStackIterator::operator*() { 156 assert(Iter != N->StackIdIndices.end()); 157 return *Iter; 158 } 159 160 template <class NodeT, class IteratorT> 161 uint64_t CallStack<NodeT, IteratorT>::back() const { 162 assert(N); 163 return N->StackIdIndices.back(); 164 } 165 166 template <class NodeT, class IteratorT> 167 typename CallStack<NodeT, IteratorT>::CallStackIterator 168 CallStack<NodeT, IteratorT>::begin() const { 169 return CallStackIterator(N, /*End*/ false); 170 } 171 172 template <class NodeT, class IteratorT> 173 typename CallStack<NodeT, IteratorT>::CallStackIterator 174 CallStack<NodeT, IteratorT>::beginAfterSharedPrefix(CallStack &Other) { 175 CallStackIterator Cur = begin(); 176 for (CallStackIterator OtherCur = Other.begin(); 177 Cur != end() && OtherCur != Other.end(); ++Cur, ++OtherCur) 178 assert(*Cur == *OtherCur); 179 return Cur; 180 } 181 182 /// Specializations for iterating through IR metadata stack contexts. 183 template <> 184 CallStack<MDNode, MDNode::op_iterator>::CallStackIterator::CallStackIterator( 185 const MDNode *N, bool End); 186 template <> 187 uint64_t CallStack<MDNode, MDNode::op_iterator>::CallStackIterator::operator*(); 188 template <> uint64_t CallStack<MDNode, MDNode::op_iterator>::back() const; 189 190 } // end namespace memprof 191 } // end namespace llvm 192 193 #endif 194