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
16using namespace llvm;
17using namespace object;
18
19// Orders increasingly by (SectionID, Address).
20int 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
28static 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
37static 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
45std::vector<std::pair<SymbolRef, uint64_t>>
46llvm::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