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
15using namespace llvm;
16using namespace object;
17
18// Orders increasingly by (SectionID, Address).
19int llvm::object::compareAddress(const SymEntry *A, const SymEntry *B) {
20  if (A->SectionID != B->SectionID)
21    return A->SectionID < B->SectionID ? -1 : 1;
22  if (A->Address != B->Address)
23    return A->Address < B->Address ? -1 : 1;
24  return 0;
25}
26
27static unsigned getSectionID(const ObjectFile &O, SectionRef Sec) {
28  if (auto *M = dyn_cast<MachOObjectFile>(&O))
29    return M->getSectionID(Sec);
30  return cast<COFFObjectFile>(O).getSectionID(Sec);
31}
32
33static unsigned getSymbolSectionID(const ObjectFile &O, SymbolRef Sym) {
34  if (auto *M = dyn_cast<MachOObjectFile>(&O))
35    return M->getSymbolSectionID(Sym);
36  return cast<COFFObjectFile>(O).getSymbolSectionID(Sym);
37}
38
39std::vector<std::pair<SymbolRef, uint64_t>>
40llvm::object::computeSymbolSizes(const ObjectFile &O) {
41  std::vector<std::pair<SymbolRef, uint64_t>> Ret;
42
43  if (const auto *E = dyn_cast<ELFObjectFileBase>(&O)) {
44    auto Syms = E->symbols();
45    if (Syms.begin() == Syms.end())
46      Syms = E->getDynamicSymbolIterators();
47    for (ELFSymbolRef Sym : Syms)
48      Ret.push_back({Sym, Sym.getSize()});
49    return Ret;
50  }
51
52  // Collect sorted symbol addresses. Include dummy addresses for the end
53  // of each section.
54  std::vector<SymEntry> Addresses;
55  unsigned SymNum = 0;
56  for (symbol_iterator I = O.symbol_begin(), E = O.symbol_end(); I != E; ++I) {
57    SymbolRef Sym = *I;
58    uint64_t Value = Sym.getValue();
59    Addresses.push_back({I, Value, SymNum, getSymbolSectionID(O, Sym)});
60    ++SymNum;
61  }
62  for (SectionRef Sec : O.sections()) {
63    uint64_t Address = Sec.getAddress();
64    uint64_t Size = Sec.getSize();
65    Addresses.push_back(
66        {O.symbol_end(), Address + Size, 0, getSectionID(O, Sec)});
67  }
68
69  if (Addresses.empty())
70    return Ret;
71
72  array_pod_sort(Addresses.begin(), Addresses.end(), compareAddress);
73
74  // Compute the size as the gap to the next symbol
75  for (unsigned I = 0, N = Addresses.size() - 1; I < N; ++I) {
76    auto &P = Addresses[I];
77    if (P.I == O.symbol_end())
78      continue;
79
80    // If multiple symbol have the same address, give both the same size.
81    unsigned NextI = I + 1;
82    while (NextI < N && Addresses[NextI].Address == P.Address)
83      ++NextI;
84
85    uint64_t Size = Addresses[NextI].Address - P.Address;
86    P.Address = Size;
87  }
88
89  // Assign the sorted symbols in the original order.
90  Ret.resize(SymNum);
91  for (SymEntry &P : Addresses) {
92    if (P.I == O.symbol_end())
93      continue;
94    Ret[P.Number] = {*P.I, P.Address};
95  }
96  return Ret;
97}
98