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| //===- MapFile.cpp --------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the -Map option. It shows lists in order and
// hierarchically the output sections, input sections, input files and
// symbol:
//
// Address Size Align Out In Symbol
// 00201000 00000015 4 .text
// 00201000 0000000e 4 test.o:(.text)
// 0020100e 00000000 0 local
// 00201005 00000000 0 f(int)
//
//===----------------------------------------------------------------------===//
#include "MapFile.h"
#include "InputFiles.h"
#include "LinkerScript.h"
#include "OutputSections.h"
#include "SymbolTable.h"
#include "Symbols.h"
#include "SyntheticSections.h"
#include "lld/Common/Strings.h"
#include "lld/Common/Threads.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
using namespace llvm::object;
namespace lld {
namespace elf {
using SymbolMapTy = DenseMap<const SectionBase *, SmallVector<Defined *, 4>>;
static constexpr char indent8[] = " "; // 8 spaces
static constexpr char indent16[] = " "; // 16 spaces
// Print out the first three columns of a line.
static void writeHeader(raw_ostream &os, uint64_t vma, uint64_t lma,
uint64_t size, uint64_t align) {
if (config->is64)
os << format("%16llx %16llx %8llx %5lld ", vma, lma, size, align);
else
os << format("%8llx %8llx %8llx %5lld ", vma, lma, size, align);
}
// Returns a list of all symbols that we want to print out.
static std::vector<Defined *> getSymbols() {
std::vector<Defined *> v;
for (InputFile *file : objectFiles)
for (Symbol *b : file->getSymbols())
if (auto *dr = dyn_cast<Defined>(b))
if (!dr->isSection() && dr->section && dr->section->isLive() &&
(dr->file == file || dr->needsPltAddr || dr->section->bss))
v.push_back(dr);
return v;
}
// Returns a map from sections to their symbols.
static SymbolMapTy getSectionSyms(ArrayRef<Defined *> syms) {
SymbolMapTy ret;
for (Defined *dr : syms)
ret[dr->section].push_back(dr);
// Sort symbols by address. We want to print out symbols in the
// order in the output file rather than the order they appeared
// in the input files.
for (auto &it : ret)
llvm::stable_sort(it.second, [](Defined *a, Defined *b) {
return a->getVA() < b->getVA();
});
return ret;
}
// Construct a map from symbols to their stringified representations.
// Demangling symbols (which is what toString() does) is slow, so
// we do that in batch using parallel-for.
static DenseMap<Symbol *, std::string>
getSymbolStrings(ArrayRef<Defined *> syms) {
std::vector<std::string> str(syms.size());
parallelForEachN(0, syms.size(), [&](size_t i) {
raw_string_ostream os(str[i]);
OutputSection *osec = syms[i]->getOutputSection();
uint64_t vma = syms[i]->getVA();
uint64_t lma = osec ? osec->getLMA() + vma - osec->getVA(0) : 0;
writeHeader(os, vma, lma, syms[i]->getSize(), 1);
os << indent16 << toString(*syms[i]);
});
DenseMap<Symbol *, std::string> ret;
for (size_t i = 0, e = syms.size(); i < e; ++i)
ret[syms[i]] = std::move(str[i]);
return ret;
}
// Print .eh_frame contents. Since the section consists of EhSectionPieces,
// we need a specialized printer for that section.
//
// .eh_frame tend to contain a lot of section pieces that are contiguous
// both in input file and output file. Such pieces are squashed before
// being displayed to make output compact.
static void printEhFrame(raw_ostream &os, const EhFrameSection *sec) {
std::vector<EhSectionPiece> pieces;
auto add = [&](const EhSectionPiece &p) {
// If P is adjacent to Last, squash the two.
if (!pieces.empty()) {
EhSectionPiece &last = pieces.back();
if (last.sec == p.sec && last.inputOff + last.size == p.inputOff &&
last.outputOff + last.size == p.outputOff) {
last.size += p.size;
return;
}
}
pieces.push_back(p);
};
// Gather section pieces.
for (const CieRecord *rec : sec->getCieRecords()) {
add(*rec->cie);
for (const EhSectionPiece *fde : rec->fdes)
add(*fde);
}
// Print out section pieces.
const OutputSection *osec = sec->getOutputSection();
for (EhSectionPiece &p : pieces) {
writeHeader(os, osec->addr + p.outputOff, osec->getLMA() + p.outputOff,
p.size, 1);
os << indent8 << toString(p.sec->file) << ":(" << p.sec->name << "+0x"
<< Twine::utohexstr(p.inputOff) + ")\n";
}
}
void writeMapFile() {
if (config->mapFile.empty())
return;
// Open a map file for writing.
std::error_code ec;
raw_fd_ostream os(config->mapFile, ec, sys::fs::OF_None);
if (ec) {
error("cannot open " + config->mapFile + ": " + ec.message());
return;
}
// Collect symbol info that we want to print out.
std::vector<Defined *> syms = getSymbols();
SymbolMapTy sectionSyms = getSectionSyms(syms);
DenseMap<Symbol *, std::string> symStr = getSymbolStrings(syms);
// Print out the header line.
int w = config->is64 ? 16 : 8;
os << right_justify("VMA", w) << ' ' << right_justify("LMA", w)
<< " Size Align Out In Symbol\n";
OutputSection* osec = nullptr;
for (BaseCommand *base : script->sectionCommands) {
if (auto *cmd = dyn_cast<SymbolAssignment>(base)) {
if (cmd->provide && !cmd->sym)
continue;
uint64_t lma = osec ? osec->getLMA() + cmd->addr - osec->getVA(0) : 0;
writeHeader(os, cmd->addr, lma, cmd->size, 1);
os << cmd->commandString << '\n';
continue;
}
osec = cast<OutputSection>(base);
writeHeader(os, osec->addr, osec->getLMA(), osec->size, osec->alignment);
os << osec->name << '\n';
// Dump symbols for each input section.
for (BaseCommand *base : osec->sectionCommands) {
if (auto *isd = dyn_cast<InputSectionDescription>(base)) {
for (InputSection *isec : isd->sections) {
if (auto *ehSec = dyn_cast<EhFrameSection>(isec)) {
printEhFrame(os, ehSec);
continue;
}
writeHeader(os, isec->getVA(0), osec->getLMA() + isec->getOffset(0),
isec->getSize(), isec->alignment);
os << indent8 << toString(isec) << '\n';
for (Symbol *sym : sectionSyms[isec])
os << symStr[sym] << '\n';
}
continue;
}
if (auto *cmd = dyn_cast<ByteCommand>(base)) {
writeHeader(os, osec->addr + cmd->offset, osec->getLMA() + cmd->offset,
cmd->size, 1);
os << indent8 << cmd->commandString << '\n';
continue;
}
if (auto *cmd = dyn_cast<SymbolAssignment>(base)) {
if (cmd->provide && !cmd->sym)
continue;
writeHeader(os, cmd->addr, osec->getLMA() + cmd->addr - osec->getVA(0),
cmd->size, 1);
os << indent8 << cmd->commandString << '\n';
continue;
}
}
}
}
static void print(StringRef a, StringRef b) {
outs() << left_justify(a, 49) << " " << b << "\n";
}
// Output a cross reference table to stdout. This is for --cref.
//
// For each global symbol, we print out a file that defines the symbol
// followed by files that uses that symbol. Here is an example.
//
// strlen /lib/x86_64-linux-gnu/libc.so.6
// tools/lld/tools/lld/CMakeFiles/lld.dir/lld.cpp.o
// lib/libLLVMSupport.a(PrettyStackTrace.cpp.o)
//
// In this case, strlen is defined by libc.so.6 and used by other two
// files.
void writeCrossReferenceTable() {
if (!config->cref)
return;
// Collect symbols and files.
MapVector<Symbol *, SetVector<InputFile *>> map;
for (InputFile *file : objectFiles) {
for (Symbol *sym : file->getSymbols()) {
if (isa<SharedSymbol>(sym))
map[sym].insert(file);
if (auto *d = dyn_cast<Defined>(sym))
if (!d->isLocal() && (!d->section || d->section->isLive()))
map[d].insert(file);
}
}
// Print out a header.
outs() << "Cross Reference Table\n\n";
print("Symbol", "File");
// Print out a table.
for (auto kv : map) {
Symbol *sym = kv.first;
SetVector<InputFile *> &files = kv.second;
print(toString(*sym), toString(sym->file));
for (InputFile *file : files)
if (file != sym->file)
print("", toString(file));
}
}
} // namespace elf
} // namespace lld
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