SymbolSize.cpp revision 341825 
1//===- SymbolSize.cpp -----------------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "llvm/Object/SymbolSize.h"
11#include "llvm/ADT/STLExtras.h"
12#include "llvm/Object/COFF.h"
13#include "llvm/Object/ELFObjectFile.h"
14#include "llvm/Object/MachO.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  return cast<COFFObjectFile>(O).getSectionID(Sec);
32}
33
34static unsigned getSymbolSectionID(const ObjectFile &O, SymbolRef Sym) {
35  if (auto *M = dyn_cast<MachOObjectFile>(&O))
36    return M->getSymbolSectionID(Sym);
37  return cast<COFFObjectFile>(O).getSymbolSectionID(Sym);
38}
39
40std::vector<std::pair<SymbolRef, uint64_t>>
41llvm::object::computeSymbolSizes(const ObjectFile &O) {
42  std::vector<std::pair<SymbolRef, uint64_t>> Ret;
43
44  if (const auto *E = dyn_cast<ELFObjectFileBase>(&O)) {
45    auto Syms = E->symbols();
46    if (Syms.begin() == Syms.end())
47      Syms = E->getDynamicSymbolIterators();
48    for (ELFSymbolRef Sym : Syms)
49      Ret.push_back({Sym, Sym.getSize()});
50    return Ret;
51  }
52
53  // Collect sorted symbol addresses. Include dummy addresses for the end
54  // of each section.
55  std::vector<SymEntry> Addresses;
56  unsigned SymNum = 0;
57  for (symbol_iterator I = O.symbol_begin(), E = O.symbol_end(); I != E; ++I) {
58    SymbolRef Sym = *I;
59    uint64_t Value = Sym.getValue();
60    Addresses.push_back({I, Value, SymNum, getSymbolSectionID(O, Sym)});
61    ++SymNum;
62  }
63  for (SectionRef Sec : O.sections()) {
64    uint64_t Address = Sec.getAddress();
65    uint64_t Size = Sec.getSize();
66    Addresses.push_back(
67        {O.symbol_end(), Address + Size, 0, getSectionID(O, Sec)});
68  }
69
70  if (Addresses.empty())
71    return Ret;
72
73  array_pod_sort(Addresses.begin(), Addresses.end(), compareAddress);
74
75  // Compute the size as the gap to the next symbol
76  for (unsigned I = 0, N = Addresses.size() - 1; I < N; ++I) {
77    auto &P = Addresses[I];
78    if (P.I == O.symbol_end())
79      continue;
80
81    // If multiple symbol have the same address, give both the same size.
82    unsigned NextI = I + 1;
83    while (NextI < N && Addresses[NextI].Address == P.Address)
84      ++NextI;
85
86    uint64_t Size = Addresses[NextI].Address - P.Address;
87    P.Address = Size;
88  }
89
90  // Assign the sorted symbols in the original order.
91  Ret.resize(SymNum);
92  for (SymEntry &P : Addresses) {
93    if (P.I == O.symbol_end())
94      continue;
95    Ret[P.Number] = {*P.I, P.Address};
96  }
97  return Ret;
98}
99