xref: /llvm-project-15.0.7/lld/MachO/MapFile.cpp (revision ed4a4e33)
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
52   // order in the output file rather than the order they appeared
53   // in the input files.
54   for (auto &it : ret)
55     llvm::stable_sort(it.second, [](Defined *a, Defined *b) {
56       return a->getVA() < b->getVA();
57     });
58   return ret;
59 }
60 
61 // Returns a list of all symbols that we want to print out.
62 static std::vector<Defined *> getSymbols() {
63   std::vector<Defined *> v;
64   for (InputFile *file : inputFiles)
65     if (isa<ObjFile>(file))
66       for (Symbol *sym : file->symbols) {
67         if (sym == nullptr)
68           continue;
69         if (auto *d = dyn_cast<Defined>(sym))
70           if (d->isec && d->getFile() == file)
71             v.push_back(d);
72       }
73   return v;
74 }
75 
76 // Construct a map from symbols to their stringified representations.
77 // Demangling symbols (which is what toString() does) is slow, so
78 // we do that in batch using parallel-for.
79 static DenseMap<Symbol *, std::string>
80 getSymbolStrings(ArrayRef<Defined *> syms) {
81   std::vector<std::string> str(syms.size());
82   parallelForEachN(0, syms.size(), [&](size_t i) {
83     raw_string_ostream os(str[i]);
84     os << toString(*syms[i]);
85   });
86 
87   DenseMap<Symbol *, std::string> ret;
88   for (size_t i = 0, e = syms.size(); i < e; ++i)
89     ret[syms[i]] = std::move(str[i]);
90   return ret;
91 }
92 
93 void macho::writeMapFile() {
94   if (config->mapFile.empty())
95     return;
96 
97   TimeTraceScope timeScope("Write map file");
98 
99   // Open a map file for writing.
100   std::error_code ec;
101   raw_fd_ostream os(config->mapFile, ec, sys::fs::OF_None);
102   if (ec) {
103     error("cannot open " + config->mapFile + ": " + ec.message());
104     return;
105   }
106 
107   // Dump output path.
108   os << format("# Path: %s\n", config->outputFile.str().c_str());
109 
110   // Dump output architecture.
111   os << format("# Arch: %s\n",
112                getArchitectureName(config->arch()).str().c_str());
113 
114   // Dump table of object files.
115   os << "# Object files:\n";
116   os << format("[%3u] %s\n", 0, (const char *)"linker synthesized");
117   uint32_t fileIndex = 1;
118   DenseMap<lld::macho::InputFile *, uint32_t> readerToFileOrdinal;
119   for (InputFile *file : inputFiles) {
120     if (isa<ObjFile>(file)) {
121       os << format("[%3u] %s\n", fileIndex, file->getName().str().c_str());
122       readerToFileOrdinal[file] = fileIndex++;
123     }
124   }
125 
126   // Collect symbol info that we want to print out.
127   std::vector<Defined *> syms = getSymbols();
128   SymbolMapTy sectionSyms = getSectionSyms(syms);
129   DenseMap<Symbol *, std::string> symStr = getSymbolStrings(syms);
130 
131   // Dump table of sections
132   os << "# Sections:\n";
133   os << "# Address\tSize    \tSegment\tSection\n";
134   for (OutputSegment *seg : outputSegments)
135     for (OutputSection *osec : seg->getSections()) {
136       if (osec->isHidden())
137         continue;
138 
139       os << format("0x%08llX\t0x%08llX\t%s\t%s\n", osec->addr, osec->getSize(),
140                    seg->name.str().c_str(), osec->name.str().c_str());
141     }
142 
143   // Dump table of symbols
144   os << "# Symbols:\n";
145   os << "# Address\t    File  Name\n";
146   for (InputSection *isec : inputSections) {
147     for (Symbol *sym : sectionSyms[isec]) {
148       os << format("0x%08llX\t[%3u] %s\n", sym->getVA(),
149                    readerToFileOrdinal[sym->getFile()], symStr[sym].c_str());
150     }
151   }
152 
153   // TODO: when we implement -dead_strip, we should dump dead stripped symbols
154 }
155