1 //===-- llvm/CodeGen/DIEHash.h - Dwarf Hashing Framework -------*- 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 support for DWARF4 hashing of DIEs. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #ifndef LLVM_LIB_CODEGEN_ASMPRINTER_DIEHASH_H 14 #define LLVM_LIB_CODEGEN_ASMPRINTER_DIEHASH_H 15 16 #include "llvm/ADT/DenseMap.h" 17 #include "llvm/CodeGen/DIE.h" 18 #include "llvm/Support/MD5.h" 19 20 namespace llvm { 21 22 class AsmPrinter; 23 24 /// An object containing the capability of hashing and adding hash 25 /// attributes onto a DIE. 26 class DIEHash { 27 // Collection of all attributes used in hashing a particular DIE. 28 struct DIEAttrs { 29 #define HANDLE_DIE_HASH_ATTR(NAME) DIEValue NAME; 30 #include "DIEHashAttributes.def" 31 }; 32 33 public: 34 DIEHash(AsmPrinter *A = nullptr) : AP(A) {} 35 36 /// Computes the CU signature. 37 uint64_t computeCUSignature(StringRef DWOName, const DIE &Die); 38 39 /// Computes the type signature. 40 uint64_t computeTypeSignature(const DIE &Die); 41 42 // Helper routines to process parts of a DIE. 43 private: 44 /// Adds the parent context of \param Parent to the hash. 45 void addParentContext(const DIE &Parent); 46 47 /// Adds the attributes of \param Die to the hash. 48 void addAttributes(const DIE &Die); 49 50 /// Computes the full DWARF4 7.27 hash of the DIE. 51 void computeHash(const DIE &Die); 52 53 // Routines that add DIEValues to the hash. 54 public: 55 /// Adds \param Value to the hash. 56 void update(uint8_t Value) { Hash.update(Value); } 57 58 /// Encodes and adds \param Value to the hash as a ULEB128. 59 void addULEB128(uint64_t Value); 60 61 /// Encodes and adds \param Value to the hash as a SLEB128. 62 void addSLEB128(int64_t Value); 63 64 private: 65 /// Adds \param Str to the hash and includes a NULL byte. 66 void addString(StringRef Str); 67 68 /// Collects the attributes of DIE \param Die into the \param Attrs 69 /// structure. 70 void collectAttributes(const DIE &Die, DIEAttrs &Attrs); 71 72 /// Hashes the attributes in \param Attrs in order. 73 void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag); 74 75 /// Hashes the data in a block like DIEValue, e.g. DW_FORM_block or 76 /// DW_FORM_exprloc. 77 void hashBlockData(const DIE::const_value_range &Values); 78 79 /// Hashes the contents pointed to in the .debug_loc section. 80 void hashLocList(const DIELocList &LocList); 81 82 /// Hashes an individual attribute. 83 void hashAttribute(const DIEValue &Value, dwarf::Tag Tag); 84 85 /// Hashes an attribute that refers to another DIE. 86 void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag, 87 const DIE &Entry); 88 89 /// Hashes a reference to a named type in such a way that is 90 /// independent of whether that type is described by a declaration or a 91 /// definition. 92 void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry, 93 StringRef Name); 94 95 /// Hashes a reference to a previously referenced type DIE. 96 void hashRepeatedTypeReference(dwarf::Attribute Attribute, 97 unsigned DieNumber); 98 99 void hashNestedType(const DIE &Die, StringRef Name); 100 101 private: 102 MD5 Hash; 103 AsmPrinter *AP; 104 DenseMap<const DIE *, unsigned> Numbering; 105 }; 106 } 107 108 #endif 109