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 class CompileUnit; 24 25 /// An object containing the capability of hashing and adding hash 26 /// attributes onto a DIE. 27 class DIEHash { 28 // Collection of all attributes used in hashing a particular DIE. 29 struct DIEAttrs { 30 #define HANDLE_DIE_HASH_ATTR(NAME) DIEValue NAME; 31 #include "DIEHashAttributes.def" 32 }; 33 34 public: AP(A)35 DIEHash(AsmPrinter *A = nullptr) : AP(A) {} 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. update(uint8_t Value)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 private: 66 /// Adds \param Str to the hash and includes a NULL byte. 67 void addString(StringRef Str); 68 69 /// Collects the attributes of DIE \param Die into the \param Attrs 70 /// structure. 71 void collectAttributes(const DIE &Die, DIEAttrs &Attrs); 72 73 /// Hashes the attributes in \param Attrs in order. 74 void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag); 75 76 /// Hashes the data in a block like DIEValue, e.g. DW_FORM_block or 77 /// DW_FORM_exprloc. 78 void hashBlockData(const DIE::const_value_range &Values); 79 80 /// Hashes the contents pointed to in the .debug_loc section. 81 void hashLocList(const DIELocList &LocList); 82 83 /// Hashes an individual attribute. 84 void hashAttribute(const DIEValue &Value, dwarf::Tag Tag); 85 86 /// Hashes an attribute that refers to another DIE. 87 void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag, 88 const DIE &Entry); 89 90 /// Hashes a reference to a named type in such a way that is 91 /// independent of whether that type is described by a declaration or a 92 /// definition. 93 void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry, 94 StringRef Name); 95 96 /// Hashes a reference to a previously referenced type DIE. 97 void hashRepeatedTypeReference(dwarf::Attribute Attribute, 98 unsigned DieNumber); 99 100 void hashNestedType(const DIE &Die, StringRef Name); 101 102 private: 103 MD5 Hash; 104 AsmPrinter *AP; 105 DenseMap<const DIE *, unsigned> Numbering; 106 }; 107 } 108 109 #endif 110