1 //===- SymbolSize.cpp -----------------------------------------------------===// 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 #include "llvm/Object/SymbolSize.h" 10 #include "llvm/ADT/STLExtras.h" 11 #include "llvm/Object/COFF.h" 12 #include "llvm/Object/ELFObjectFile.h" 13 #include "llvm/Object/MachO.h" 14 #include "llvm/Object/Wasm.h" 15 #include "llvm/Object/XCOFFObjectFile.h" 16 17 using namespace llvm; 18 using namespace object; 19 20 // Orders increasingly by (SectionID, Address). 21 int llvm::object::compareAddress(const SymEntry *A, const SymEntry *B) { 22 if (A->SectionID != B->SectionID) 23 return A->SectionID < B->SectionID ? -1 : 1; 24 if (A->Address != B->Address) 25 return A->Address < B->Address ? -1 : 1; 26 return 0; 27 } 28 29 static unsigned getSectionID(const ObjectFile &O, SectionRef Sec) { 30 if (auto *M = dyn_cast<MachOObjectFile>(&O)) 31 return M->getSectionID(Sec); 32 if (isa<WasmObjectFile>(&O)) 33 return Sec.getIndex(); 34 if (isa<XCOFFObjectFile>(&O)) 35 return Sec.getIndex(); 36 return cast<COFFObjectFile>(O).getSectionID(Sec); 37 } 38 39 static unsigned getSymbolSectionID(const ObjectFile &O, SymbolRef Sym) { 40 if (auto *M = dyn_cast<MachOObjectFile>(&O)) 41 return M->getSymbolSectionID(Sym); 42 if (const auto *M = dyn_cast<WasmObjectFile>(&O)) 43 return M->getSymbolSectionId(Sym); 44 if (const auto *M = dyn_cast<XCOFFObjectFile>(&O)) 45 return M->getSymbolSectionID(Sym); 46 return cast<COFFObjectFile>(O).getSymbolSectionID(Sym); 47 } 48 49 std::vector<std::pair<SymbolRef, uint64_t>> 50 llvm::object::computeSymbolSizes(const ObjectFile &O) { 51 std::vector<std::pair<SymbolRef, uint64_t>> Ret; 52 53 if (const auto *E = dyn_cast<ELFObjectFileBase>(&O)) { 54 auto Syms = E->symbols(); 55 if (Syms.empty()) 56 Syms = E->getDynamicSymbolIterators(); 57 for (ELFSymbolRef Sym : Syms) 58 Ret.push_back({Sym, Sym.getSize()}); 59 return Ret; 60 } 61 62 if (const auto *E = dyn_cast<XCOFFObjectFile>(&O)) { 63 for (XCOFFSymbolRef Sym : E->symbols()) 64 Ret.push_back({Sym, Sym.getSize()}); 65 return Ret; 66 } 67 68 // Collect sorted symbol addresses. Include dummy addresses for the end 69 // of each section. 70 std::vector<SymEntry> Addresses; 71 unsigned SymNum = 0; 72 for (symbol_iterator I = O.symbol_begin(), E = O.symbol_end(); I != E; ++I) { 73 SymbolRef Sym = *I; 74 Expected<uint64_t> ValueOrErr = Sym.getValue(); 75 if (!ValueOrErr) 76 // TODO: Actually report errors helpfully. 77 report_fatal_error(ValueOrErr.takeError()); 78 Addresses.push_back({I, *ValueOrErr, SymNum, getSymbolSectionID(O, Sym)}); 79 ++SymNum; 80 } 81 for (SectionRef Sec : O.sections()) { 82 uint64_t Address = Sec.getAddress(); 83 uint64_t Size = Sec.getSize(); 84 Addresses.push_back( 85 {O.symbol_end(), Address + Size, 0, getSectionID(O, Sec)}); 86 } 87 88 if (Addresses.empty()) 89 return Ret; 90 91 array_pod_sort(Addresses.begin(), Addresses.end(), compareAddress); 92 93 // Compute the size as the gap to the next symbol. If multiple symbols have 94 // the same address, give both the same size. Because Addresses is sorted, 95 // use two pointers to keep track of the current symbol vs. the next symbol 96 // that doesn't have the same address for size computation. 97 for (unsigned I = 0, NextI = 0, N = Addresses.size() - 1; I < N; ++I) { 98 auto &P = Addresses[I]; 99 if (P.I == O.symbol_end()) 100 continue; 101 102 // If the next pointer is behind, update it to the next symbol. 103 if (NextI <= I) { 104 NextI = I + 1; 105 while (NextI < N && Addresses[NextI].Address == P.Address) 106 ++NextI; 107 } 108 109 uint64_t Size = Addresses[NextI].Address - P.Address; 110 P.Address = Size; 111 } 112 113 // Assign the sorted symbols in the original order. 114 Ret.resize(SymNum); 115 for (SymEntry &P : Addresses) { 116 if (P.I == O.symbol_end()) 117 continue; 118 Ret[P.Number] = {*P.I, P.Address}; 119 } 120 return Ret; 121 } 122