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      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 
     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 
     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 
     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>>
     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