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 "InputFiles.h"
23 #include "OutputSections.h"
24 #include "OutputSegment.h"
25 #include "SymbolTable.h"
26 #include "Symbols.h"
27 #include "SyntheticSections.h"
28 #include "lld/Common/Strings.h"
29 #include "llvm/ADT/MapVector.h"
30 #include "llvm/ADT/SetVector.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.
writeHeader(raw_ostream & os,int64_t vma,uint64_t lma,uint64_t size)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.
getSymbols()52 static std::vector<Symbol *> getSymbols() {
53   std::vector<Symbol *> v;
54   for (InputFile *file : symtab->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.
getSectionSyms(ArrayRef<Symbol * > syms)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>
getSymbolStrings(ArrayRef<Symbol * > syms)75 getSymbolStrings(ArrayRef<Symbol *> syms) {
76   std::vector<std::string> str(syms.size());
77   parallelForEachN(0, syms.size(), [&](size_t i) {
78     raw_string_ostream os(str[i]);
79     auto &chunk = *syms[i]->getChunk();
80     uint64_t fileOffset = chunk.outputSec->getOffset() + chunk.outputOffset;
81     uint64_t vma = -1;
82     uint64_t size = 0;
83     if (auto *DD = dyn_cast<DefinedData>(syms[i])) {
84       vma = DD->getVirtualAddress();
85       size = DD->getSize();
86       fileOffset += DD->offset;
87     }
88     if (auto *DF = dyn_cast<DefinedFunction>(syms[i])) {
89       size = DF->function->getSize();
90     }
91     writeHeader(os, vma, fileOffset, size);
92     os.indent(16) << toString(*syms[i]);
93   });
94 
95   DenseMap<Symbol *, std::string> ret;
96   for (size_t i = 0, e = syms.size(); i < e; ++i)
97     ret[syms[i]] = std::move(str[i]);
98   return ret;
99 }
100 
writeMapFile(ArrayRef<OutputSection * > outputSections)101 void lld::wasm::writeMapFile(ArrayRef<OutputSection *> outputSections) {
102   if (config->mapFile.empty())
103     return;
104 
105   // Open a map file for writing.
106   std::error_code ec;
107   raw_fd_ostream os(config->mapFile, ec, sys::fs::OF_None);
108   if (ec) {
109     error("cannot open " + config->mapFile + ": " + ec.message());
110     return;
111   }
112 
113   // Collect symbol info that we want to print out.
114   std::vector<Symbol *> syms = getSymbols();
115   SymbolMapTy sectionSyms = getSectionSyms(syms);
116   DenseMap<Symbol *, std::string> symStr = getSymbolStrings(syms);
117 
118   // Print out the header line.
119   os << "    Addr      Off     Size Out     In      Symbol\n";
120 
121   for (OutputSection *osec : outputSections) {
122     writeHeader(os, -1, osec->getOffset(), osec->getSize());
123     os << toString(*osec) << '\n';
124     if (auto *code = dyn_cast<CodeSection>(osec)) {
125       for (auto *chunk : code->functions) {
126         writeHeader(os, -1, chunk->outputSec->getOffset() + chunk->outputOffset,
127                     chunk->getSize());
128         os.indent(8) << toString(chunk) << '\n';
129         for (Symbol *sym : sectionSyms[chunk])
130           os << symStr[sym] << '\n';
131       }
132     } else if (auto *data = dyn_cast<DataSection>(osec)) {
133       for (auto *oseg : data->segments) {
134         writeHeader(os, oseg->startVA, data->getOffset() + oseg->sectionOffset,
135                     oseg->size);
136         os << oseg->name << '\n';
137         for (auto *chunk : oseg->inputSegments) {
138           writeHeader(os, oseg->startVA + chunk->outputSegmentOffset,
139                       chunk->outputSec->getOffset() + chunk->outputOffset,
140                       chunk->getSize());
141           os.indent(8) << toString(chunk) << '\n';
142           for (Symbol *sym : sectionSyms[chunk])
143             os << symStr[sym] << '\n';
144         }
145       }
146     }
147   }
148 }
149