lld/wasm/MapFile.cpp

   1 //===- MapFile.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 // This file implements the -Map option. It shows lists in order and
  10 // hierarchically the output sections, input sections, input files and
  11 // symbol:
  12 //
  13 //       Addr      Off   Size    Out     In      Symbol
  14 //          - 00000015     10    .text
  15 //          - 0000000e     10            test.o:(.text)
  16 //          - 00000000      5                    local
  17 //          - 00000000      5                    f(int)
  18 //
  19 //===----------------------------------------------------------------------===//
  20
  21 #include "MapFile.h"
  22 #include "InputElement.h"
  23 #include "InputFiles.h"
  24 #include "OutputSections.h"
  25 #include "OutputSegment.h"
  26 #include "SymbolTable.h"
  27 #include "Symbols.h"
  28 #include "SyntheticSections.h"
  29 #include "lld/Common/Strings.h"
  30 #include "llvm/ADT/MapVector.h"
  31 #include "llvm/ADT/SetVector.h"
  32 #include "llvm/Support/Parallel.h"
  33 #include "llvm/Support/raw_ostream.h"
  34
  35 using namespace llvm;
  36 using namespace llvm::object;
  37 using namespace lld;
  38 using namespace lld::wasm;
  39
  40 using SymbolMapTy = DenseMap<const InputChunk *, SmallVector<Symbol *, 4>>;
  41
  42 // Print out the first three columns of a line.
  43 static void writeHeader(raw_ostream &os, int64_t vma, uint64_t lma,
  44                         uint64_t size) {
  45   // Not all entries in the map has a virtual memory address (e.g. functions)
  46   if (vma == -1)
  47     os << format("       - %8llx %8llx ", lma, size);
  48   else
  49     os << format("%8llx %8llx %8llx ", vma, lma, size);
  50 }
  51
  52 // Returns a list of all symbols that we want to print out.
  53 static std::vector<Symbol *> getSymbols() {
  54   std::vector<Symbol *> v;
  55   for (InputFile *file : symtab->objectFiles)
  56     for (Symbol *b : file->getSymbols())
  57       if (auto *dr = dyn_cast<Symbol>(b))
  58         if ((!isa<SectionSymbol>(dr)) && dr->isLive() &&
  59             (dr->getFile() == file))
  60           v.push_back(dr);
  61   return v;
  62 }
  63
  64 // Returns a map from sections to their symbols.
  65 static SymbolMapTy getSectionSyms(ArrayRef<Symbol *> syms) {
  66   SymbolMapTy ret;
  67   for (Symbol *dr : syms)
  68     ret[dr->getChunk()].push_back(dr);
  69   return ret;
  70 }
  71
  72 // Construct a map from symbols to their stringified representations.
  73 // Demangling symbols (which is what toString() does) is slow, so
  74 // we do that in batch using parallel-for.
  75 static DenseMap<Symbol *, std::string>
  76 getSymbolStrings(ArrayRef<Symbol *> syms) {
  77   std::vector<std::string> str(syms.size());
  78   parallelForEachN(0, syms.size(), [&](size_t i) {
  79     raw_string_ostream os(str[i]);
  80     auto *chunk = syms[i]->getChunk();
  81     if (chunk == nullptr)
  82       return;
  83     uint64_t fileOffset = chunk->outputSec != nullptr
  84                               ? chunk->outputSec->getOffset() + chunk->outSecOff
  85                               : 0;
  86     uint64_t vma = -1;
  87     uint64_t size = 0;
  88     if (auto *DD = dyn_cast<DefinedData>(syms[i])) {
  89       vma = DD->getVA();
  90       size = DD->getSize();
  91       fileOffset += DD->value;
  92     }
  93     if (auto *DF = dyn_cast<DefinedFunction>(syms[i])) {
  94       size = DF->function->getSize();
  95     }
  96     writeHeader(os, vma, fileOffset, size);
  97     os.indent(16) << toString(*syms[i]);
  98   });
  99
 100   DenseMap<Symbol *, std::string> ret;
 101   for (size_t i = 0, e = syms.size(); i < e; ++i)
 102     ret[syms[i]] = std::move(str[i]);
 103   return ret;
 104 }
 105
 106 void lld::wasm::writeMapFile(ArrayRef<OutputSection *> outputSections) {
 107   if (config->mapFile.empty())
 108     return;
 109
 110   // Open a map file for writing.
 111   std::error_code ec;
 112   raw_fd_ostream os(config->mapFile, ec, sys::fs::OF_None);
 113   if (ec) {
 114     error("cannot open " + config->mapFile + ": " + ec.message());
 115     return;
 116   }
 117
 118   // Collect symbol info that we want to print out.
 119   std::vector<Symbol *> syms = getSymbols();
 120   SymbolMapTy sectionSyms = getSectionSyms(syms);
 121   DenseMap<Symbol *, std::string> symStr = getSymbolStrings(syms);
 122
 123   // Print out the header line.
 124   os << "    Addr      Off     Size Out     In      Symbol\n";
 125
 126   for (OutputSection *osec : outputSections) {
 127     writeHeader(os, -1, osec->getOffset(), osec->getSize());
 128     os << toString(*osec) << '\n';
 129     if (auto *code = dyn_cast<CodeSection>(osec)) {
 130       for (auto *chunk : code->functions) {
 131         writeHeader(os, -1, chunk->outputSec->getOffset() + chunk->outSecOff,
 132                     chunk->getSize());
 133         os.indent(8) << toString(chunk) << '\n';
 134         for (Symbol *sym : sectionSyms[chunk])
 135           os << symStr[sym] << '\n';
 136       }
 137     } else if (auto *data = dyn_cast<DataSection>(osec)) {
 138       for (auto *oseg : data->segments) {
 139         writeHeader(os, oseg->startVA, data->getOffset() + oseg->sectionOffset,
 140                     oseg->size);
 141         os << oseg->name << '\n';
 142         for (auto *chunk : oseg->inputSegments) {
 143           uint64_t offset =
 144               chunk->outputSec != nullptr
 145                   ? chunk->outputSec->getOffset() + chunk->outSecOff
 146                   : 0;
 147           writeHeader(os, chunk->getVA(), offset, chunk->getSize());
 148           os.indent(8) << toString(chunk) << '\n';
 149           for (Symbol *sym : sectionSyms[chunk])
 150             os << symStr[sym] << '\n';
 151         }
 152       }
 153     } else if (auto *globals = dyn_cast<GlobalSection>(osec)) {
 154       for (auto *global : globals->inputGlobals) {
 155         writeHeader(os, global->getAssignedIndex(), 0, 0);
 156         os.indent(8) << global->getName() << '\n';
 157       }
 158     }
 159     // TODO: other section/symbol types
 160   }
 161 }