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 outputFile, arch, input files, output sections and
11 // symbol:
12 //
13 // # Path: test
14 // # Arch: x86_84
15 // # Object files:
16 // [  0] linker synthesized
17 // [  1] a.o
18 // # Sections:
19 // # Address  Size      Segment  Section
20 // 0x1000005C0  0x0000004C  __TEXT  __text
21 // # Symbols:
22 // # Address  File  Name
23 // 0x1000005C0  [  1] _main
24 //
25 //===----------------------------------------------------------------------===//
26 
27 #include "MapFile.h"
28 #include "Config.h"
29 #include "InputFiles.h"
30 #include "InputSection.h"
31 #include "OutputSection.h"
32 #include "OutputSegment.h"
33 #include "Symbols.h"
34 #include "Target.h"
35 #include "llvm/Support/Parallel.h"
36 #include "llvm/Support/TimeProfiler.h"
37 
38 using namespace llvm;
39 using namespace llvm::sys;
40 using namespace lld;
41 using namespace lld::macho;
42 
43 using SymbolMapTy = DenseMap<const InputSection *, SmallVector<Defined *, 4>>;
44 
45 // Returns a map from sections to their symbols.
46 static SymbolMapTy getSectionSyms(ArrayRef<Defined *> syms) {
47   SymbolMapTy ret;
48   for (Defined *dr : syms)
49     ret[dr->isec].push_back(dr);
50 
51   // Sort symbols by address. We want to print out symbols in the order they
52   // appear in the output file rather than the order they appeared in the input
53   // files.
54   for (auto &it : ret)
55     parallelSort(
56         it.second.begin(), it.second.end(), [](Defined *a, Defined *b) {
57           return a->getVA() != b->getVA() ? a->getVA() < b->getVA()
58                                           : a->getName() < b->getName();
59         });
60   return ret;
61 }
62 
63 // Returns a list of all symbols that we want to print out.
64 static std::vector<Defined *> getSymbols() {
65   std::vector<Defined *> v;
66   for (InputFile *file : inputFiles)
67     if (isa<ObjFile>(file))
68       for (Symbol *sym : file->symbols)
69         if (auto *d = dyn_cast_or_null<Defined>(sym))
70           if (d->isLive() && d->isec && d->getFile() == file) {
71             assert(!shouldOmitFromOutput(d->isec));
72             v.push_back(d);
73           }
74   return v;
75 }
76 
77 // Construct a map from symbols to their stringified representations.
78 // Demangling symbols (which is what toString() does) is slow, so
79 // we do that in batch using parallel-for.
80 static DenseMap<Symbol *, std::string>
81 getSymbolStrings(ArrayRef<Defined *> syms) {
82   std::vector<std::string> str(syms.size());
83   parallelForEachN(0, syms.size(), [&](size_t i) {
84     raw_string_ostream os(str[i]);
85     os << toString(*syms[i]);
86   });
87 
88   DenseMap<Symbol *, std::string> ret;
89   for (size_t i = 0, e = syms.size(); i < e; ++i)
90     ret[syms[i]] = std::move(str[i]);
91   return ret;
92 }
93 
94 void macho::writeMapFile() {
95   if (config->mapFile.empty())
96     return;
97 
98   TimeTraceScope timeScope("Write map file");
99 
100   // Open a map file for writing.
101   std::error_code ec;
102   raw_fd_ostream os(config->mapFile, ec, sys::fs::OF_None);
103   if (ec) {
104     error("cannot open " + config->mapFile + ": " + ec.message());
105     return;
106   }
107 
108   // Dump output path.
109   os << format("# Path: %s\n", config->outputFile.str().c_str());
110 
111   // Dump output architecture.
112   os << format("# Arch: %s\n",
113                getArchitectureName(config->arch()).str().c_str());
114 
115   // Dump table of object files.
116   os << "# Object files:\n";
117   os << format("[%3u] %s\n", 0, (const char *)"linker synthesized");
118   uint32_t fileIndex = 1;
119   DenseMap<lld::macho::InputFile *, uint32_t> readerToFileOrdinal;
120   for (InputFile *file : inputFiles) {
121     if (isa<ObjFile>(file)) {
122       os << format("[%3u] %s\n", fileIndex, file->getName().str().c_str());
123       readerToFileOrdinal[file] = fileIndex++;
124     }
125   }
126 
127   // Collect symbol info that we want to print out.
128   std::vector<Defined *> syms = getSymbols();
129   SymbolMapTy sectionSyms = getSectionSyms(syms);
130   DenseMap<Symbol *, std::string> symStr = getSymbolStrings(syms);
131 
132   // Dump table of sections
133   os << "# Sections:\n";
134   os << "# Address\tSize    \tSegment\tSection\n";
135   for (OutputSegment *seg : outputSegments)
136     for (OutputSection *osec : seg->getSections()) {
137       if (osec->isHidden())
138         continue;
139 
140       os << format("0x%08llX\t0x%08llX\t%s\t%s\n", osec->addr, osec->getSize(),
141                    seg->name.str().c_str(), osec->name.str().c_str());
142     }
143 
144   // Dump table of symbols
145   os << "# Symbols:\n";
146   os << "# Address\t    File  Name\n";
147   for (InputSection *isec : inputSections) {
148     auto symsIt = sectionSyms.find(isec);
149     assert(!shouldOmitFromOutput(isec) || (symsIt == sectionSyms.end()));
150     if (symsIt == sectionSyms.end())
151       continue;
152     for (Symbol *sym : symsIt->second) {
153       os << format("0x%08llX\t[%3u] %s\n", sym->getVA(),
154                    readerToFileOrdinal[sym->getFile()], symStr[sym].c_str());
155     }
156   }
157 
158   // TODO: when we implement -dead_strip, we should dump dead stripped symbols
159 }
160