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, DwarfCompileUnit *CU = nullptr) 35 : AP(A), CU(CU) {} 36 37 /// Computes the CU signature. 38 uint64_t computeCUSignature(StringRef DWOName, const DIE &Die); 39 40 /// Computes the type signature. 41 uint64_t computeTypeSignature(const DIE &Die); 42 43 // Helper routines to process parts of a DIE. 44 private: 45 /// Adds the parent context of \param Parent to the hash. 46 void addParentContext(const DIE &Parent); 47 48 /// Adds the attributes of \param Die to the hash. 49 void addAttributes(const DIE &Die); 50 51 /// Computes the full DWARF4 7.27 hash of the DIE. 52 void computeHash(const DIE &Die); 53 54 // Routines that add DIEValues to the hash. 55 public: 56 /// Adds \param Value to the hash. 57 void update(uint8_t Value) { Hash.update(Value); } 58 59 /// Encodes and adds \param Value to the hash as a ULEB128. 60 void addULEB128(uint64_t Value); 61 62 /// Encodes and adds \param Value to the hash as a SLEB128. 63 void addSLEB128(int64_t Value); 64 65 void hashRawTypeReference(const DIE &Entry); 66 67 private: 68 /// Adds \param Str to the hash and includes a NULL byte. 69 void addString(StringRef Str); 70 71 /// Collects the attributes of DIE \param Die into the \param Attrs 72 /// structure. 73 void collectAttributes(const DIE &Die, DIEAttrs &Attrs); 74 75 /// Hashes the attributes in \param Attrs in order. 76 void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag); 77 78 /// Hashes the data in a block like DIEValue, e.g. DW_FORM_block or 79 /// DW_FORM_exprloc. 80 void hashBlockData(const DIE::const_value_range &Values); 81 82 /// Hashes the contents pointed to in the .debug_loc section. 83 void hashLocList(const DIELocList &LocList); 84 85 /// Hashes an individual attribute. 86 void hashAttribute(const DIEValue &Value, dwarf::Tag Tag); 87 88 /// Hashes an attribute that refers to another DIE. 89 void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag, 90 const DIE &Entry); 91 92 /// Hashes a reference to a named type in such a way that is 93 /// independent of whether that type is described by a declaration or a 94 /// definition. 95 void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry, 96 StringRef Name); 97 98 /// Hashes a reference to a previously referenced type DIE. 99 void hashRepeatedTypeReference(dwarf::Attribute Attribute, 100 unsigned DieNumber); 101 102 void hashNestedType(const DIE &Die, StringRef Name); 103 104 private: 105 MD5 Hash; 106 AsmPrinter *AP; 107 DwarfCompileUnit *CU; 108 DenseMap<const DIE *, unsigned> Numbering; 109 }; 110 } 111 112 #endif 113