MachO/MapFile.cpp - llvm-project/lld - 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, which maps address ranges to their
 // respective contents, plus the input file these contents were originally from.
 // The contents (typically symbols) are listed in address order. Dead-stripped
 // contents are included as well.
 //
 // # Path: test
 // # Arch: x86_84
 // # Object files:
 // [  0] linker synthesized
 // [  1] a.o
 // # Sections:
 // # Address    Size       Segment  Section
 // 0x1000005C0  0x0000004C __TEXT   __text
 // # Symbols:
 // # Address    Size       File  Name
 // 0x1000005C0  0x00000001 [  1] _main
 // # Dead Stripped Symbols:
 // #            Size       File  Name
 // <<dead>>     0x00000001 [  1] _foo
 //
 //===----------------------------------------------------------------------===//

 #include "MapFile.h"
 #include "ConcatOutputSection.h"
 #include "Config.h"
 #include "InputFiles.h"
 #include "InputSection.h"
 #include "OutputSegment.h"
 #include "Symbols.h"
 #include "SyntheticSections.h"
 #include "Target.h"
 #include "lld/Common/ErrorHandler.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/Support/Parallel.h"
 #include "llvm/Support/TimeProfiler.h"

 using namespace llvm;
 using namespace llvm::sys;
 using namespace lld;
 using namespace lld::macho;

 struct CStringInfo {
   uint32_t fileIndex;
   StringRef str;
 };

 struct MapInfo {
   SmallVector<InputFile *> files;
   SmallVector<Defined *> deadSymbols;
   DenseMap<const OutputSection *,
            SmallVector<std::pair<uint64_t /*addr*/, CStringInfo>>>
       liveCStringsForSection;
   SmallVector<CStringInfo> deadCStrings;
 };

 static MapInfo gatherMapInfo() {
   MapInfo info;
   for (InputFile *file : inputFiles) {
     bool isReferencedFile = false;

     if (isa<ObjFile>(file) || isa<BitcodeFile>(file)) {
       uint32_t fileIndex = info.files.size() + 1;

       // Gather the dead symbols. We don't have to bother with the live ones
       // because we will pick them up as we iterate over the OutputSections
       // later.
       for (Symbol *sym : file->symbols) {
         if (auto *d = dyn_cast_or_null<Defined>(sym))
           // Only emit the prevailing definition of a symbol. Also, don't emit
           // the symbol if it is part of a cstring section (we use the literal
           // value instead, similar to ld64)
           if (d->isec() && d->getFile() == file &&
               !isa<CStringInputSection>(d->isec())) {
             isReferencedFile = true;
             if (!d->isLive())
               info.deadSymbols.push_back(d);
           }
       }

       // Gather all the cstrings (both live and dead). A CString(Output)Section
       // doesn't provide us a way of figuring out which InputSections its
       // cstring contents came from, so we need to build up that mapping here.
       for (const Section *sec : file->sections) {
         for (const Subsection &subsec : sec->subsections) {
           if (auto isec = dyn_cast<CStringInputSection>(subsec.isec)) {
             auto &liveCStrings = info.liveCStringsForSection[isec->parent];
             for (const auto &[i, piece] : llvm::enumerate(isec->pieces)) {
               if (piece.live)
                 liveCStrings.push_back({isec->parent->addr + piece.outSecOff,
                                         {fileIndex, isec->getStringRef(i)}});
               else
                 info.deadCStrings.push_back({fileIndex, isec->getStringRef(i)});
               isReferencedFile = true;
             }
           } else {
             break;
           }
         }
       }
     } else if (const auto *dylibFile = dyn_cast<DylibFile>(file)) {
       isReferencedFile = dylibFile->isReferenced();
     }

     if (isReferencedFile)
       info.files.push_back(file);
   }

   // cstrings are not stored in sorted order in their OutputSections, so we sort
   // them here.
   for (auto &liveCStrings : info.liveCStringsForSection)
     parallelSort(liveCStrings.second, [](const auto &p1, const auto &p2) {
       return p1.first < p2.first;
     });
   return info;
 }

 // We use this instead of `toString(const InputFile *)` as we don't want to
 // include the dylib install name in our output.
 static void printFileName(raw_fd_ostream &os, const InputFile *f) {
   if (f->archiveName.empty())
     os << f->getName();
   else
     os << f->archiveName << "(" << path::filename(f->getName()) + ")";
 }

 // For printing the contents of the __stubs and __la_symbol_ptr sections.
 static void printStubsEntries(
     raw_fd_ostream &os,
     const DenseMap<lld::macho::InputFile *, uint32_t> &readerToFileOrdinal,
     const OutputSection *osec, size_t entrySize) {
   for (const Symbol *sym : in.stubs->getEntries())
     os << format("0x%08llX\t0x%08zX\t[%3u] %s\n",
                  osec->addr + sym->stubsIndex * entrySize, entrySize,
                  readerToFileOrdinal.lookup(sym->getFile()),
                  sym->getName().str().data());
 }

 static void printNonLazyPointerSection(raw_fd_ostream &os,
                                        NonLazyPointerSectionBase *osec) {
   // ld64 considers stubs to belong to particular files, but considers GOT
   // entries to be linker-synthesized. Not sure why they made that decision, but
   // I think we can follow suit unless there's demand for better symbol-to-file
   // associations.
   for (const Symbol *sym : osec->getEntries())
     os << format("0x%08llX\t0x%08zX\t[  0] non-lazy-pointer-to-local: %s\n",
                  osec->addr + sym->gotIndex * target->wordSize,
                  target->wordSize, sym->getName().str().data());
 }

 static uint64_t getSymSizeForMap(Defined *sym) {
   if (sym->wasIdenticalCodeFolded)
     return 0;
   return sym->size;
 }

 void macho::writeMapFile() {
   if (config->mapFile.empty())
     return;

   TimeTraceScope timeScope("Write map file");

   // 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;
   }

   os << format("# Path: %s\n", config->outputFile.str().c_str());
   os << format("# Arch: %s\n",
                getArchitectureName(config->arch()).str().c_str());

   MapInfo info = gatherMapInfo();

   os << "# Object files:\n";
   os << format("[%3u] %s\n", 0, (const char *)"linker synthesized");
   uint32_t fileIndex = 1;
   DenseMap<lld::macho::InputFile *, uint32_t> readerToFileOrdinal;
   for (InputFile *file : info.files) {
     os << format("[%3u] ", fileIndex);
     printFileName(os, file);
     os << "\n";
     readerToFileOrdinal[file] = fileIndex++;
   }

   os << "# Sections:\n";
   os << "# Address\tSize    \tSegment\tSection\n";
   for (OutputSegment *seg : outputSegments)
     for (OutputSection *osec : seg->getSections()) {
       if (osec->isHidden())
         continue;

       os << format("0x%08llX\t0x%08llX\t%s\t%s\n", osec->addr, osec->getSize(),
                    seg->name.str().c_str(), osec->name.str().c_str());
     }

   // Shared function to print an array of symbols.
   auto printIsecArrSyms = [&](const std::vector<ConcatInputSection *> &arr) {
     for (const ConcatInputSection *isec : arr) {
       for (Defined *sym : isec->symbols) {
         if (!(isPrivateLabel(sym->getName()) && getSymSizeForMap(sym) == 0))
           os << format("0x%08llX\t0x%08llX\t[%3u] %s\n", sym->getVA(),
                        getSymSizeForMap(sym),
                        readerToFileOrdinal[sym->getFile()],
                        sym->getName().str().data());
       }
     }
   };

   os << "# Symbols:\n";
   os << "# Address\tSize    \tFile  Name\n";
   for (const OutputSegment *seg : outputSegments) {
     for (const OutputSection *osec : seg->getSections()) {
       if (auto *concatOsec = dyn_cast<ConcatOutputSection>(osec)) {
         printIsecArrSyms(concatOsec->inputs);
       } else if (osec == in.cStringSection || osec == in.objcMethnameSection) {
         const auto &liveCStrings = info.liveCStringsForSection.lookup(osec);
         uint64_t lastAddr = 0; // strings will never start at address 0, so this
                                // is a sentinel value
         for (const auto &[addr, info] : liveCStrings) {
           uint64_t size = 0;
           if (addr != lastAddr)
             size = info.str.size() + 1; // include null terminator
           lastAddr = addr;
           os << format("0x%08llX\t0x%08llX\t[%3u] literal string: ", addr, size,
                        info.fileIndex);
           os.write_escaped(info.str) << "\n";
         }
       } else if (osec == (void *)in.unwindInfo) {
         os << format("0x%08llX\t0x%08llX\t[  0] compact unwind info\n",
                      osec->addr, osec->getSize());
       } else if (osec == in.stubs) {
         printStubsEntries(os, readerToFileOrdinal, osec, target->stubSize);
       } else if (osec == in.lazyPointers) {
         printStubsEntries(os, readerToFileOrdinal, osec, target->wordSize);
       } else if (osec == in.stubHelper) {
         // yes, ld64 calls it "helper helper"...
         os << format("0x%08llX\t0x%08llX\t[  0] helper helper\n", osec->addr,
                      osec->getSize());
       } else if (osec == in.got) {
         printNonLazyPointerSection(os, in.got);
       } else if (osec == in.tlvPointers) {
         printNonLazyPointerSection(os, in.tlvPointers);
       } else if (osec == in.objcMethList) {
         printIsecArrSyms(in.objcMethList->getInputs());
       }
       // TODO print other synthetic sections
     }
   }

   if (config->deadStrip) {
     os << "# Dead Stripped Symbols:\n";
     os << "#        \tSize    \tFile  Name\n";
     for (Defined *sym : info.deadSymbols) {
       assert(!sym->isLive());
       os << format("<<dead>>\t0x%08llX\t[%3u] %s\n", getSymSizeForMap(sym),
                    readerToFileOrdinal[sym->getFile()],
                    sym->getName().str().data());
     }
     for (CStringInfo &cstrInfo : info.deadCStrings) {
       os << format("<<dead>>\t0x%08zX\t[%3u] literal string: ",
                    cstrInfo.str.size() + 1, cstrInfo.fileIndex);
       os.write_escaped(cstrInfo.str) << "\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, which maps address ranges to their
	// respective contents, plus the input file these contents were originally from.
	// The contents (typically symbols) are listed in address order. Dead-stripped
	// contents are included as well.
	//
	// # Path: test
	// # Arch: x86_84
	// # Object files:
	// [ 0] linker synthesized
	// [ 1] a.o
	// # Sections:
	// # Address Size Segment Section
	// 0x1000005C0 0x0000004C __TEXT __text
	// # Symbols:
	// # Address Size File Name
	// 0x1000005C0 0x00000001 [ 1] _main
	// # Dead Stripped Symbols:
	// # Size File Name
	// <<dead>> 0x00000001 [ 1] _foo
	//
	//===----------------------------------------------------------------------===//

	#include "MapFile.h"
	#include "ConcatOutputSection.h"
	#include "Config.h"
	#include "InputFiles.h"
	#include "InputSection.h"
	#include "OutputSegment.h"
	#include "Symbols.h"
	#include "SyntheticSections.h"
	#include "Target.h"
	#include "lld/Common/ErrorHandler.h"
	#include "llvm/ADT/DenseMap.h"
	#include "llvm/Support/Parallel.h"
	#include "llvm/Support/TimeProfiler.h"

	using namespace llvm;
	using namespace llvm::sys;
	using namespace lld;
	using namespace lld::macho;

	struct CStringInfo {
	uint32_t fileIndex;
	StringRef str;
	};

	struct MapInfo {
	SmallVector<InputFile *> files;
	SmallVector<Defined *> deadSymbols;
	DenseMap<const OutputSection *,
	SmallVector<std::pair<uint64_t /addr/, CStringInfo>>>
	liveCStringsForSection;
	SmallVector<CStringInfo> deadCStrings;
	};

	static MapInfo gatherMapInfo() {
	MapInfo info;
	for (InputFile *file : inputFiles) {
	bool isReferencedFile = false;

	if (isa<ObjFile>(file) \|\| isa<BitcodeFile>(file)) {
	uint32_t fileIndex = info.files.size() + 1;

	// Gather the dead symbols. We don't have to bother with the live ones
	// because we will pick them up as we iterate over the OutputSections
	// later.
	for (Symbol *sym : file->symbols) {
	if (auto *d = dyn_cast_or_null<Defined>(sym))
	// Only emit the prevailing definition of a symbol. Also, don't emit
	// the symbol if it is part of a cstring section (we use the literal
	// value instead, similar to ld64)
	if (d->isec() && d->getFile() == file &&
	!isa<CStringInputSection>(d->isec())) {
	isReferencedFile = true;
	if (!d->isLive())
	info.deadSymbols.push_back(d);
	}
	}

	// Gather all the cstrings (both live and dead). A CString(Output)Section
	// doesn't provide us a way of figuring out which InputSections its
	// cstring contents came from, so we need to build up that mapping here.
	for (const Section *sec : file->sections) {
	for (const Subsection &subsec : sec->subsections) {
	if (auto isec = dyn_cast<CStringInputSection>(subsec.isec)) {
	auto &liveCStrings = info.liveCStringsForSection[isec->parent];
	for (const auto &[i, piece] : llvm::enumerate(isec->pieces)) {
	if (piece.live)
	liveCStrings.push_back({isec->parent->addr + piece.outSecOff,
	{fileIndex, isec->getStringRef(i)}});
	else
	info.deadCStrings.push_back({fileIndex, isec->getStringRef(i)});
	isReferencedFile = true;
	}
	} else {
	break;
	}
	}
	}
	} else if (const auto *dylibFile = dyn_cast<DylibFile>(file)) {
	isReferencedFile = dylibFile->isReferenced();
	}

	if (isReferencedFile)
	info.files.push_back(file);
	}

	// cstrings are not stored in sorted order in their OutputSections, so we sort
	// them here.
	for (auto &liveCStrings : info.liveCStringsForSection)
	parallelSort(liveCStrings.second, [](const auto &p1, const auto &p2) {
	return p1.first < p2.first;
	});
	return info;
	}

	// We use this instead of `toString(const InputFile *)` as we don't want to
	// include the dylib install name in our output.
	static void printFileName(raw_fd_ostream &os, const InputFile *f) {
	if (f->archiveName.empty())
	os << f->getName();
	else
	os << f->archiveName << "(" << path::filename(f->getName()) + ")";
	}

	// For printing the contents of the __stubs and __la_symbol_ptr sections.
	static void printStubsEntries(
	raw_fd_ostream &os,
	const DenseMap<lld::macho::InputFile *, uint32_t> &readerToFileOrdinal,
	const OutputSection *osec, size_t entrySize) {
	for (const Symbol *sym : in.stubs->getEntries())
	os << format("0x%08llX\t0x%08zX\t[%3u] %s\n",
	osec->addr + sym->stubsIndex * entrySize, entrySize,
	readerToFileOrdinal.lookup(sym->getFile()),
	sym->getName().str().data());
	}

	static void printNonLazyPointerSection(raw_fd_ostream &os,
	NonLazyPointerSectionBase *osec) {
	// ld64 considers stubs to belong to particular files, but considers GOT
	// entries to be linker-synthesized. Not sure why they made that decision, but
	// I think we can follow suit unless there's demand for better symbol-to-file
	// associations.
	for (const Symbol *sym : osec->getEntries())
	os << format("0x%08llX\t0x%08zX\t[ 0] non-lazy-pointer-to-local: %s\n",
	osec->addr + sym->gotIndex * target->wordSize,
	target->wordSize, sym->getName().str().data());
	}

	static uint64_t getSymSizeForMap(Defined *sym) {
	if (sym->wasIdenticalCodeFolded)
	return 0;
	return sym->size;
	}

	void macho::writeMapFile() {
	if (config->mapFile.empty())
	return;

	TimeTraceScope timeScope("Write map file");

	// 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;
	}

	os << format("# Path: %s\n", config->outputFile.str().c_str());
	os << format("# Arch: %s\n",
	getArchitectureName(config->arch()).str().c_str());

	MapInfo info = gatherMapInfo();

	os << "# Object files:\n";
	os << format("[%3u] %s\n", 0, (const char *)"linker synthesized");
	uint32_t fileIndex = 1;
	DenseMap<lld::macho::InputFile *, uint32_t> readerToFileOrdinal;
	for (InputFile *file : info.files) {
	os << format("[%3u] ", fileIndex);
	printFileName(os, file);
	os << "\n";
	readerToFileOrdinal[file] = fileIndex++;
	}

	os << "# Sections:\n";
	os << "# Address\tSize \tSegment\tSection\n";
	for (OutputSegment *seg : outputSegments)
	for (OutputSection *osec : seg->getSections()) {
	if (osec->isHidden())
	continue;

	os << format("0x%08llX\t0x%08llX\t%s\t%s\n", osec->addr, osec->getSize(),
	seg->name.str().c_str(), osec->name.str().c_str());
	}

	// Shared function to print an array of symbols.
	auto printIsecArrSyms = [&](const std::vector<ConcatInputSection *> &arr) {
	for (const ConcatInputSection *isec : arr) {
	for (Defined *sym : isec->symbols) {
	if (!(isPrivateLabel(sym->getName()) && getSymSizeForMap(sym) == 0))
	os << format("0x%08llX\t0x%08llX\t[%3u] %s\n", sym->getVA(),
	getSymSizeForMap(sym),
	readerToFileOrdinal[sym->getFile()],
	sym->getName().str().data());
	}
	}
	};

	os << "# Symbols:\n";
	os << "# Address\tSize \tFile Name\n";
	for (const OutputSegment *seg : outputSegments) {
	for (const OutputSection *osec : seg->getSections()) {
	if (auto *concatOsec = dyn_cast<ConcatOutputSection>(osec)) {
	printIsecArrSyms(concatOsec->inputs);
	} else if (osec == in.cStringSection \|\| osec == in.objcMethnameSection) {
	const auto &liveCStrings = info.liveCStringsForSection.lookup(osec);
	uint64_t lastAddr = 0; // strings will never start at address 0, so this
	// is a sentinel value
	for (const auto &[addr, info] : liveCStrings) {
	uint64_t size = 0;
	if (addr != lastAddr)
	size = info.str.size() + 1; // include null terminator
	lastAddr = addr;
	os << format("0x%08llX\t0x%08llX\t[%3u] literal string: ", addr, size,
	info.fileIndex);
	os.write_escaped(info.str) << "\n";
	}
	} else if (osec == (void *)in.unwindInfo) {
	os << format("0x%08llX\t0x%08llX\t[ 0] compact unwind info\n",
	osec->addr, osec->getSize());
	} else if (osec == in.stubs) {
	printStubsEntries(os, readerToFileOrdinal, osec, target->stubSize);
	} else if (osec == in.lazyPointers) {
	printStubsEntries(os, readerToFileOrdinal, osec, target->wordSize);
	} else if (osec == in.stubHelper) {
	// yes, ld64 calls it "helper helper"...
	os << format("0x%08llX\t0x%08llX\t[ 0] helper helper\n", osec->addr,
	osec->getSize());
	} else if (osec == in.got) {
	printNonLazyPointerSection(os, in.got);
	} else if (osec == in.tlvPointers) {
	printNonLazyPointerSection(os, in.tlvPointers);
	} else if (osec == in.objcMethList) {
	printIsecArrSyms(in.objcMethList->getInputs());
	}
	// TODO print other synthetic sections
	}
	}

	if (config->deadStrip) {
	os << "# Dead Stripped Symbols:\n";
	os << "# \tSize \tFile Name\n";
	for (Defined *sym : info.deadSymbols) {
	assert(!sym->isLive());
	os << format("<<dead>>\t0x%08llX\t[%3u] %s\n", getSymSizeForMap(sym),
	readerToFileOrdinal[sym->getFile()],
	sym->getName().str().data());
	}
	for (CStringInfo &cstrInfo : info.deadCStrings) {
	os << format("<<dead>>\t0x%08zX\t[%3u] literal string: ",
	cstrInfo.str.size() + 1, cstrInfo.fileIndex);
	os.write_escaped(cstrInfo.str) << "\n";
	}
	}
	}