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