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/Compiler.h" 19 #include "llvm/Support/MD5.h" 20 21 namespace llvm { 22 23 class AsmPrinter; 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: 35 DIEHash(AsmPrinter *A = nullptr, DwarfCompileUnit *CU = nullptr) 36 : AP(A), CU(CU) {} 37 38 /// Computes the CU signature. 39 uint64_t computeCUSignature(StringRef DWOName, const DIE &Die); 40 41 /// Computes the type signature. 42 LLVM_ABI_FOR_TEST uint64_t computeTypeSignature(const DIE &Die); 43 44 // Helper routines to process parts of a DIE. 45 private: 46 /// Adds the parent context of \param Parent to the hash. 47 void addParentContext(const DIE &Parent); 48 49 /// Adds the attributes of \param Die to the hash. 50 void addAttributes(const DIE &Die); 51 52 /// Computes the full DWARF4 7.27 hash of the DIE. 53 void computeHash(const DIE &Die); 54 55 // Routines that add DIEValues to the hash. 56 public: 57 /// Adds \param Value to the hash. 58 void update(uint8_t Value) { Hash.update(Value); } 59 60 /// Encodes and adds \param Value to the hash as a ULEB128. 61 void addULEB128(uint64_t Value); 62 63 /// Encodes and adds \param Value to the hash as a SLEB128. 64 void addSLEB128(int64_t Value); 65 66 void hashRawTypeReference(const DIE &Entry); 67 68 private: 69 /// Adds \param Str to the hash and includes a NULL byte. 70 void addString(StringRef Str); 71 72 /// Collects the attributes of DIE \param Die into the \param Attrs 73 /// structure. 74 void collectAttributes(const DIE &Die, DIEAttrs &Attrs); 75 76 /// Hashes the attributes in \param Attrs in order. 77 void hashAttributes(const DIEAttrs &Attrs, dwarf::Tag Tag); 78 79 /// Hashes the data in a block like DIEValue, e.g. DW_FORM_block or 80 /// DW_FORM_exprloc. 81 void hashBlockData(const DIE::const_value_range &Values); 82 83 /// Hashes the contents pointed to in the .debug_loc section. 84 void hashLocList(const DIELocList &LocList); 85 86 /// Hashes an individual attribute. 87 void hashAttribute(const DIEValue &Value, dwarf::Tag Tag); 88 89 /// Hashes an attribute that refers to another DIE. 90 void hashDIEEntry(dwarf::Attribute Attribute, dwarf::Tag Tag, 91 const DIE &Entry); 92 93 /// Hashes a reference to a named type in such a way that is 94 /// independent of whether that type is described by a declaration or a 95 /// definition. 96 void hashShallowTypeReference(dwarf::Attribute Attribute, const DIE &Entry, 97 StringRef Name); 98 99 /// Hashes a reference to a previously referenced type DIE. 100 void hashRepeatedTypeReference(dwarf::Attribute Attribute, 101 unsigned DieNumber); 102 103 void hashNestedType(const DIE &Die, StringRef Name); 104 105 private: 106 MD5 Hash; 107 AsmPrinter *AP; 108 DwarfCompileUnit *CU; 109 DenseMap<const DIE *, unsigned> Numbering; 110 }; 111 } 112 113 #endif 114