lld/ELF/MapFile.cpp - llvm-project - Git at Google

 //===- 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 "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/Support/Parallel.h"
 #include "llvm/Support/TimeProfiler.h"
 #include "llvm/Support/raw_ostream.h"

 using namespace llvm;
 using namespace llvm::object;
 using namespace lld;
 using namespace lld::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";
   }
 }

 static void writeMapFile(raw_fd_ostream &os) {
   // 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 (SectionCommand *cmd : script->sectionCommands) {
     if (auto *assign = dyn_cast<SymbolAssignment>(cmd)) {
       if (assign->provide && !assign->sym)
         continue;
       uint64_t lma = osec ? osec->getLMA() + assign->addr - osec->getVA(0) : 0;
       writeHeader(os, assign->addr, lma, assign->size, 1);
       os << assign->commandString << '\n';
       continue;
     }

     osec = cast<OutputSection>(cmd);
     writeHeader(os, osec->addr, osec->getLMA(), osec->size, osec->alignment);
     os << osec->name << '\n';

     // Dump symbols for each input section.
     for (SectionCommand *subCmd : osec->commands) {
       if (auto *isd = dyn_cast<InputSectionDescription>(subCmd)) {
         for (InputSection *isec : isd->sections) {
           if (auto *ehSec = dyn_cast<EhFrameSection>(isec)) {
             printEhFrame(os, ehSec);
             continue;
           }

           writeHeader(os, isec->getVA(), osec->getLMA() + isec->outSecOff,
                       isec->getSize(), isec->alignment);
           os << indent8 << toString(isec) << '\n';
           for (Symbol *sym : sectionSyms[isec])
             os << symStr[sym] << '\n';
         }
         continue;
       }

       if (auto *data = dyn_cast<ByteCommand>(subCmd)) {
         writeHeader(os, osec->addr + data->offset,
                     osec->getLMA() + data->offset, data->size, 1);
         os << indent8 << data->commandString << '\n';
         continue;
       }

       if (auto *assign = dyn_cast<SymbolAssignment>(subCmd)) {
         if (assign->provide && !assign->sym)
           continue;
         writeHeader(os, assign->addr,
                     osec->getLMA() + assign->addr - osec->getVA(0),
                     assign->size, 1);
         os << indent8 << assign->commandString << '\n';
         continue;
       }
     }
   }
 }

 void elf::writeWhyExtract() {
   if (config->whyExtract.empty())
     return;

   std::error_code ec;
   raw_fd_ostream os(config->whyExtract, ec, sys::fs::OF_None);
   if (ec) {
     error("cannot open --why-extract= file " + config->whyExtract + ": " +
           ec.message());
     return;
   }

   os << "reference\textracted\tsymbol\n";
   for (auto &entry : whyExtract) {
     os << std::get<0>(entry) << '\t' << toString(std::get<1>(entry)) << '\t'
        << toString(std::get<2>(entry)) << '\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.
 static void writeCref(raw_fd_ostream &os) {
   // 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);
     }
   }

   auto print = [&](StringRef a, StringRef b) {
     os << left_justify(a, 49) << ' ' << b << '\n';
   };

   // Print a blank line and a header. The format matches GNU ld.
   os << "\nCross 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));
   }
 }

 void elf::writeMapAndCref() {
   if (config->mapFile.empty() && !config->cref)
     return;

   llvm::TimeTraceScope timeScope("Write map file");

   // Open a map file for writing.
   std::error_code ec;
   StringRef mapFile = config->mapFile.empty() ? "-" : config->mapFile;
   raw_fd_ostream os(mapFile, ec, sys::fs::OF_None);
   if (ec) {
     error("cannot open " + mapFile + ": " + ec.message());
     return;
   }

   if (!config->mapFile.empty())
     writeMapFile(os);
   if (config->cref)
     writeCref(os);
 }

 void elf::writeArchiveStats() {
   if (config->printArchiveStats.empty())
     return;

   std::error_code ec;
   raw_fd_ostream os(config->printArchiveStats, ec, sys::fs::OF_None);
   if (ec) {
     error("--print-archive-stats=: cannot open " + config->printArchiveStats +
           ": " + ec.message());
     return;
   }

   os << "members\textracted\tarchive\n";
   for (const ArchiveFile *f : archiveFiles)
     os << f->getMemberCount() << '\t' << f->getExtractedMemberCount() << '\t'
        << f->getName() << '\n';
 }
	//===- 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 "llvm/ADT/MapVector.h"
	#include "llvm/ADT/SetVector.h"
	#include "llvm/Support/Parallel.h"
	#include "llvm/Support/TimeProfiler.h"
	#include "llvm/Support/raw_ostream.h"

	using namespace llvm;
	using namespace llvm::object;
	using namespace lld;
	using namespace lld::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";
	}
	}

	static void writeMapFile(raw_fd_ostream &os) {
	// 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 (SectionCommand *cmd : script->sectionCommands) {
	if (auto *assign = dyn_cast<SymbolAssignment>(cmd)) {
	if (assign->provide && !assign->sym)
	continue;
	uint64_t lma = osec ? osec->getLMA() + assign->addr - osec->getVA(0) : 0;
	writeHeader(os, assign->addr, lma, assign->size, 1);
	os << assign->commandString << '\n';
	continue;
	}

	osec = cast<OutputSection>(cmd);
	writeHeader(os, osec->addr, osec->getLMA(), osec->size, osec->alignment);
	os << osec->name << '\n';

	// Dump symbols for each input section.
	for (SectionCommand *subCmd : osec->commands) {
	if (auto *isd = dyn_cast<InputSectionDescription>(subCmd)) {
	for (InputSection *isec : isd->sections) {
	if (auto *ehSec = dyn_cast<EhFrameSection>(isec)) {
	printEhFrame(os, ehSec);
	continue;
	}

	writeHeader(os, isec->getVA(), osec->getLMA() + isec->outSecOff,
	isec->getSize(), isec->alignment);
	os << indent8 << toString(isec) << '\n';
	for (Symbol *sym : sectionSyms[isec])
	os << symStr[sym] << '\n';
	}
	continue;
	}

	if (auto *data = dyn_cast<ByteCommand>(subCmd)) {
	writeHeader(os, osec->addr + data->offset,
	osec->getLMA() + data->offset, data->size, 1);
	os << indent8 << data->commandString << '\n';
	continue;
	}

	if (auto *assign = dyn_cast<SymbolAssignment>(subCmd)) {
	if (assign->provide && !assign->sym)
	continue;
	writeHeader(os, assign->addr,
	osec->getLMA() + assign->addr - osec->getVA(0),
	assign->size, 1);
	os << indent8 << assign->commandString << '\n';
	continue;
	}
	}
	}
	}

	void elf::writeWhyExtract() {
	if (config->whyExtract.empty())
	return;

	std::error_code ec;
	raw_fd_ostream os(config->whyExtract, ec, sys::fs::OF_None);
	if (ec) {
	error("cannot open --why-extract= file " + config->whyExtract + ": " +
	ec.message());
	return;
	}

	os << "reference\textracted\tsymbol\n";
	for (auto &entry : whyExtract) {
	os << std::get<0>(entry) << '\t' << toString(std::get<1>(entry)) << '\t'
	<< toString(std::get<2>(entry)) << '\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.
	static void writeCref(raw_fd_ostream &os) {
	// 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);
	}
	}

	auto print = [&](StringRef a, StringRef b) {
	os << left_justify(a, 49) << ' ' << b << '\n';
	};

	// Print a blank line and a header. The format matches GNU ld.
	os << "\nCross 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));
	}
	}

	void elf::writeMapAndCref() {
	if (config->mapFile.empty() && !config->cref)
	return;

	llvm::TimeTraceScope timeScope("Write map file");

	// Open a map file for writing.
	std::error_code ec;
	StringRef mapFile = config->mapFile.empty() ? "-" : config->mapFile;
	raw_fd_ostream os(mapFile, ec, sys::fs::OF_None);
	if (ec) {
	error("cannot open " + mapFile + ": " + ec.message());
	return;
	}

	if (!config->mapFile.empty())
	writeMapFile(os);
	if (config->cref)
	writeCref(os);
	}

	void elf::writeArchiveStats() {
	if (config->printArchiveStats.empty())
	return;

	std::error_code ec;
	raw_fd_ostream os(config->printArchiveStats, ec, sys::fs::OF_None);
	if (ec) {
	error("--print-archive-stats=: cannot open " + config->printArchiveStats +
	": " + ec.message());
	return;
	}

	os << "members\textracted\tarchive\n";
	for (const ArchiveFile *f : archiveFiles)
	os << f->getMemberCount() << '\t' << f->getExtractedMemberCount() << '\t'
	<< f->getName() << '\n';
	}