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