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
34using namespace llvm;
35using namespace llvm::object;
36using namespace lld;
37using namespace lld::wasm;
38
39using SymbolMapTy = DenseMap<const InputChunk *, SmallVector<Symbol *, 4>>;
40
41// Print out the first three columns of a line.
42static 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(Fmt: " - %8llx %8llx ", Vals: lma, Vals: size);
47 else
48 os << format(Fmt: "%8llx %8llx %8llx ", Vals: vma, Vals: lma, Vals: size);
49}
50
51// Returns a list of all symbols that we want to print out.
52static 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>(Val: b))
57 if ((!isa<SectionSymbol>(Val: dr)) && dr->isLive() &&
58 (dr->getFile() == file))
59 v.push_back(x: dr);
60 return v;
61}
62
63// Returns a map from sections to their symbols.
64static SymbolMapTy getSectionSyms(ArrayRef<Symbol *> syms) {
65 SymbolMapTy ret;
66 for (Symbol *dr : syms)
67 ret[dr->getChunk()].push_back(Elt: 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.
74static DenseMap<Symbol *, std::string>
75getSymbolStrings(ArrayRef<Symbol *> syms) {
76 std::vector<std::string> str(syms.size());
77 parallelFor(Begin: 0, End: syms.size(), Fn: [&](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>(Val: syms[i])) {
88 vma = DD->getVA();
89 size = DD->getSize();
90 fileOffset += DD->value;
91 }
92 if (auto *DF = dyn_cast<DefinedFunction>(Val: syms[i])) {
93 size = DF->function->getSize();
94 }
95 writeHeader(os, vma, lma: fileOffset, size);
96 os.indent(NumSpaces: 16) << toString(sym: *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
105void 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(msg: "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, vma: -1, lma: osec->getOffset(), size: osec->getSize());
127 os << toString(section: *osec) << '\n';
128 if (auto *code = dyn_cast<CodeSection>(Val: osec)) {
129 for (auto *chunk : code->functions) {
130 writeHeader(os, vma: -1, lma: chunk->outputSec->getOffset() + chunk->outSecOff,
131 size: chunk->getSize());
132 os.indent(NumSpaces: 8) << toString(chunk) << '\n';
133 for (Symbol *sym : sectionSyms[chunk])
134 os << symStr[sym] << '\n';
135 }
136 } else if (auto *data = dyn_cast<DataSection>(Val: osec)) {
137 for (auto *oseg : data->segments) {
138 writeHeader(os, vma: oseg->startVA, lma: data->getOffset() + oseg->sectionOffset,
139 size: 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, vma: chunk->getVA(), lma: offset, size: chunk->getSize());
147 os.indent(NumSpaces: 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>(Val: osec)) {
153 for (auto *global : globals->inputGlobals) {
154 writeHeader(os, vma: global->getAssignedIndex(), lma: 0, size: 0);
155 os.indent(NumSpaces: 8) << global->getName() << '\n';
156 }
157 }
158 // TODO: other section/symbol types
159 }
160}
161

source code of lld/wasm/MapFile.cpp