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 "SyntheticSections.h"
35 #include "Target.h"
36 #include "llvm/Support/Parallel.h"
37 #include "llvm/Support/TimeProfiler.h"
38
39 using namespace llvm;
40 using namespace llvm::sys;
41 using namespace lld;
42 using namespace lld::macho;
43
44 using Symbols = std::vector<Defined *>;
45 // Returns a pair where the left element is a container of all live Symbols and
46 // the right element is a container of all dead symbols.
getSymbols()47 static std::pair<Symbols, Symbols> getSymbols() {
48 Symbols liveSymbols, deadSymbols;
49 for (InputFile *file : inputFiles)
50 if (isa<ObjFile>(file))
51 for (Symbol *sym : file->symbols)
52 if (auto *d = dyn_cast_or_null<Defined>(sym))
53 if (d->isec && d->getFile() == file) {
54 if (d->isLive()) {
55 assert(!shouldOmitFromOutput(d->isec));
56 liveSymbols.push_back(d);
57 } else {
58 deadSymbols.push_back(d);
59 }
60 }
61 parallelSort(liveSymbols.begin(), liveSymbols.end(),
62 [](Defined *a, Defined *b) {
63 return a->getVA() != b->getVA() ? a->getVA() < b->getVA()
64 : a->getName() < b->getName();
65 });
66 parallelSort(
67 deadSymbols.begin(), deadSymbols.end(),
68 [](Defined *a, Defined *b) { return a->getName() < b->getName(); });
69 return {std::move(liveSymbols), std::move(deadSymbols)};
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>
getSymbolStrings(ArrayRef<Defined * > syms)76 getSymbolStrings(ArrayRef<Defined *> syms) {
77 std::vector<std::string> str(syms.size());
78 parallelFor(0, syms.size(), [&](size_t i) {
79 raw_string_ostream os(str[i]);
80 Defined *sym = syms[i];
81
82 switch (sym->isec->kind()) {
83 case InputSection::CStringLiteralKind: {
84 // Output "literal string: <string literal>"
85 const auto *isec = cast<CStringInputSection>(sym->isec);
86 const StringPiece &piece = isec->getStringPiece(sym->value);
87 assert(
88 sym->value == piece.inSecOff &&
89 "We expect symbols to always point to the start of a StringPiece.");
90 StringRef str = isec->getStringRef(&piece - &(*isec->pieces.begin()));
91 assert(str.back() == '\000');
92 (os << "literal string: ")
93 // Remove null sequence at the end
94 .write_escaped(str.substr(0, str.size() - 1));
95 break;
96 }
97 case InputSection::ConcatKind:
98 case InputSection::WordLiteralKind:
99 os << toString(*sym);
100 }
101 });
102
103 DenseMap<Symbol *, std::string> ret;
104 for (size_t i = 0, e = syms.size(); i < e; ++i)
105 ret[syms[i]] = std::move(str[i]);
106 return ret;
107 }
108
writeMapFile()109 void macho::writeMapFile() {
110 if (config->mapFile.empty())
111 return;
112
113 TimeTraceScope timeScope("Write map file");
114
115 // Open a map file for writing.
116 std::error_code ec;
117 raw_fd_ostream os(config->mapFile, ec, sys::fs::OF_None);
118 if (ec) {
119 error("cannot open " + config->mapFile + ": " + ec.message());
120 return;
121 }
122
123 // Dump output path.
124 os << format("# Path: %s\n", config->outputFile.str().c_str());
125
126 // Dump output architecture.
127 os << format("# Arch: %s\n",
128 getArchitectureName(config->arch()).str().c_str());
129
130 // Dump table of object files.
131 os << "# Object files:\n";
132 os << format("[%3u] %s\n", 0, (const char *)"linker synthesized");
133 uint32_t fileIndex = 1;
134 DenseMap<lld::macho::InputFile *, uint32_t> readerToFileOrdinal;
135 for (InputFile *file : inputFiles) {
136 if (isa<ObjFile>(file)) {
137 os << format("[%3u] %s\n", fileIndex, file->getName().str().c_str());
138 readerToFileOrdinal[file] = fileIndex++;
139 }
140 }
141
142 // Dump table of sections
143 os << "# Sections:\n";
144 os << "# Address\tSize \tSegment\tSection\n";
145 for (OutputSegment *seg : outputSegments)
146 for (OutputSection *osec : seg->getSections()) {
147 if (osec->isHidden())
148 continue;
149
150 os << format("0x%08llX\t0x%08llX\t%s\t%s\n", osec->addr, osec->getSize(),
151 seg->name.str().c_str(), osec->name.str().c_str());
152 }
153
154 // Dump table of symbols
155 Symbols liveSymbols, deadSymbols;
156 std::tie(liveSymbols, deadSymbols) = getSymbols();
157
158 DenseMap<Symbol *, std::string> liveSymbolStrings =
159 getSymbolStrings(liveSymbols);
160 os << "# Symbols:\n";
161 os << "# Address\t File Name\n";
162 for (Symbol *sym : liveSymbols) {
163 assert(sym->isLive());
164 os << format("0x%08llX\t[%3u] %s\n", sym->getVA(),
165 readerToFileOrdinal[sym->getFile()],
166 liveSymbolStrings[sym].c_str());
167 }
168
169 if (config->deadStrip) {
170 DenseMap<Symbol *, std::string> deadSymbolStrings =
171 getSymbolStrings(deadSymbols);
172 os << "# Dead Stripped Symbols:\n";
173 os << "# Address\t File Name\n";
174 for (Symbol *sym : deadSymbols) {
175 assert(!sym->isLive());
176 os << format("<<dead>>\t[%3u] %s\n", readerToFileOrdinal[sym->getFile()],
177 deadSymbolStrings[sym].c_str());
178 }
179 }
180 }
181