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
16 using namespace llvm;
17 using namespace object;
18
19 // Orders increasingly by (SectionID, Address).
compareAddress(const SymEntry * A,const SymEntry * B)20 int llvm::object::compareAddress(const SymEntry *A, const SymEntry *B) {
21 if (A->SectionID != B->SectionID)
22 return A->SectionID < B->SectionID ? -1 : 1;
23 if (A->Address != B->Address)
24 return A->Address < B->Address ? -1 : 1;
25 return 0;
26 }
27
getSectionID(const ObjectFile & O,SectionRef Sec)28 static unsigned getSectionID(const ObjectFile &O, SectionRef Sec) {
29 if (auto *M = dyn_cast<MachOObjectFile>(&O))
30 return M->getSectionID(Sec);
31 if (isa<WasmObjectFile>(&O))
32 return Sec.getIndex();
33
34 return cast<COFFObjectFile>(O).getSectionID(Sec);
35 }
36
getSymbolSectionID(const ObjectFile & O,SymbolRef Sym)37 static unsigned getSymbolSectionID(const ObjectFile &O, SymbolRef Sym) {
38 if (auto *M = dyn_cast<MachOObjectFile>(&O))
39 return M->getSymbolSectionID(Sym);
40 if (const auto *M = dyn_cast<WasmObjectFile>(&O))
41 return M->getSymbolSectionId(Sym);
42 return cast<COFFObjectFile>(O).getSymbolSectionID(Sym);
43 }
44
45 std::vector<std::pair<SymbolRef, uint64_t>>
computeSymbolSizes(const ObjectFile & O)46 llvm::object::computeSymbolSizes(const ObjectFile &O) {
47 std::vector<std::pair<SymbolRef, uint64_t>> Ret;
48
49 if (const auto *E = dyn_cast<ELFObjectFileBase>(&O)) {
50 auto Syms = E->symbols();
51 if (Syms.begin() == Syms.end())
52 Syms = E->getDynamicSymbolIterators();
53 for (ELFSymbolRef Sym : Syms)
54 Ret.push_back({Sym, Sym.getSize()});
55 return Ret;
56 }
57
58 // Collect sorted symbol addresses. Include dummy addresses for the end
59 // of each section.
60 std::vector<SymEntry> Addresses;
61 unsigned SymNum = 0;
62 for (symbol_iterator I = O.symbol_begin(), E = O.symbol_end(); I != E; ++I) {
63 SymbolRef Sym = *I;
64 Expected<uint64_t> ValueOrErr = Sym.getValue();
65 if (!ValueOrErr)
66 // TODO: Actually report errors helpfully.
67 report_fatal_error(ValueOrErr.takeError());
68 Addresses.push_back({I, *ValueOrErr, SymNum, getSymbolSectionID(O, Sym)});
69 ++SymNum;
70 }
71 for (SectionRef Sec : O.sections()) {
72 uint64_t Address = Sec.getAddress();
73 uint64_t Size = Sec.getSize();
74 Addresses.push_back(
75 {O.symbol_end(), Address + Size, 0, getSectionID(O, Sec)});
76 }
77
78 if (Addresses.empty())
79 return Ret;
80
81 array_pod_sort(Addresses.begin(), Addresses.end(), compareAddress);
82
83 // Compute the size as the gap to the next symbol
84 for (unsigned I = 0, N = Addresses.size() - 1; I < N; ++I) {
85 auto &P = Addresses[I];
86 if (P.I == O.symbol_end())
87 continue;
88
89 // If multiple symbol have the same address, give both the same size.
90 unsigned NextI = I + 1;
91 while (NextI < N && Addresses[NextI].Address == P.Address)
92 ++NextI;
93
94 uint64_t Size = Addresses[NextI].Address - P.Address;
95 P.Address = Size;
96 }
97
98 // Assign the sorted symbols in the original order.
99 Ret.resize(SymNum);
100 for (SymEntry &P : Addresses) {
101 if (P.I == O.symbol_end())
102 continue;
103 Ret[P.Number] = {*P.I, P.Address};
104 }
105 return Ret;
106 }
107