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https://github.com/c64scene-ar/llvm-6502.git
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Improve performance of iterating over children and accessing the member file buffer by caching the file size and moving code out to the header. This also makes getBuffer return a StringRef instead of a MemoryBuffer. Both fixing a memory leak and removing a malloc. This takes getBuffer from ~10% of the time in lld to unmeasurable. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174272 91177308-0d34-0410-b5e6-96231b3b80d8
302 lines
9.5 KiB
C++
302 lines
9.5 KiB
C++
//===- Archive.cpp - ar File Format implementation --------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the ArchiveObjectFile class.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Object/Archive.h"
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#include "llvm/ADT/APInt.h"
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#include "llvm/Support/Endian.h"
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#include "llvm/Support/MemoryBuffer.h"
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using namespace llvm;
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using namespace object;
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static const char *Magic = "!<arch>\n";
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static bool isInternalMember(const ArchiveMemberHeader &amh) {
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static const char *const internals[] = {
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"/",
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"//",
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"#_LLVM_SYM_TAB_#"
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};
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StringRef name = amh.getName();
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for (std::size_t i = 0; i < sizeof(internals) / sizeof(*internals); ++i) {
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if (name == internals[i])
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return true;
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}
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return false;
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}
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void Archive::anchor() { }
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error_code Archive::Child::getName(StringRef &Result) const {
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StringRef name = ToHeader(Data.data())->getName();
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// Check if it's a special name.
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if (name[0] == '/') {
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if (name.size() == 1) { // Linker member.
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Result = name;
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return object_error::success;
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}
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if (name.size() == 2 && name[1] == '/') { // String table.
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Result = name;
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return object_error::success;
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}
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// It's a long name.
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// Get the offset.
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std::size_t offset;
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if (name.substr(1).rtrim(" ").getAsInteger(10, offset))
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llvm_unreachable("Long name offset is not an integer");
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const char *addr = Parent->StringTable->Data.begin()
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+ sizeof(ArchiveMemberHeader)
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+ offset;
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// Verify it.
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if (Parent->StringTable == Parent->end_children()
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|| addr < (Parent->StringTable->Data.begin()
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+ sizeof(ArchiveMemberHeader))
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|| addr > (Parent->StringTable->Data.begin()
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+ sizeof(ArchiveMemberHeader)
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+ Parent->StringTable->getSize()))
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return object_error::parse_failed;
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// GNU long file names end with a /.
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if (Parent->kind() == K_GNU) {
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StringRef::size_type End = StringRef(addr).find('/');
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Result = StringRef(addr, End);
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} else {
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Result = addr;
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}
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return object_error::success;
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} else if (name.startswith("#1/")) {
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uint64_t name_size;
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if (name.substr(3).rtrim(" ").getAsInteger(10, name_size))
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llvm_unreachable("Long name length is not an ingeter");
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Result = Data.substr(sizeof(ArchiveMemberHeader), name_size);
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return object_error::success;
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}
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// It's a simple name.
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if (name[name.size() - 1] == '/')
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Result = name.substr(0, name.size() - 1);
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else
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Result = name;
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return object_error::success;
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}
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error_code Archive::Child::getAsBinary(OwningPtr<Binary> &Result) const {
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OwningPtr<Binary> ret;
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OwningPtr<MemoryBuffer> Buff;
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if (error_code ec = getMemoryBuffer(Buff))
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return ec;
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if (error_code ec = createBinary(Buff.take(), ret))
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return ec;
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Result.swap(ret);
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return object_error::success;
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}
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Archive::Archive(MemoryBuffer *source, error_code &ec)
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: Binary(Binary::ID_Archive, source) {
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// Check for sufficient magic.
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if (!source || source->getBufferSize()
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< (8 + sizeof(ArchiveMemberHeader) + 2) // Smallest archive.
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|| StringRef(source->getBufferStart(), 8) != Magic) {
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ec = object_error::invalid_file_type;
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return;
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}
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// Get the special members.
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child_iterator i = begin_children(false);
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child_iterator e = end_children();
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StringRef name;
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if ((ec = i->getName(name)))
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return;
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// Below is the pattern that is used to figure out the archive format
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// GNU archive format
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// First member : / (points to the symbol table )
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// Second member : // (may exist, if it exists, points to the string table)
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// Note : The string table is used if the filename exceeds 15 characters
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// BSD archive format
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// First member : __.SYMDEF (points to the symbol table)
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// There is no string table, if the filename exceeds 15 characters or has a
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// embedded space, the filename has #1/<size>, The size represents the size
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// of the filename that needs to be read after the archive header
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// COFF archive format
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// First member : /
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// Second member : / (provides a directory of symbols)
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// Third member : // contains the string table, this is present even if the
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// string table is empty
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if (name == "/") {
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SymbolTable = i;
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StringTable = e;
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if (i != e) ++i;
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if (i == e) {
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ec = object_error::parse_failed;
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return;
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}
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if ((ec = i->getName(name)))
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return;
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if (name[0] != '/') {
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Format = K_GNU;
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} else if ((name.size() > 1) && (name == "//")) {
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Format = K_GNU;
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StringTable = i;
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++i;
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} else {
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Format = K_COFF;
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if (i != e) {
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SymbolTable = i;
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++i;
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}
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if (i != e) {
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StringTable = i;
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}
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}
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} else if (name == "__.SYMDEF") {
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Format = K_BSD;
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SymbolTable = i;
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StringTable = e;
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}
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ec = object_error::success;
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}
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Archive::child_iterator Archive::begin_children(bool skip_internal) const {
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const char *Loc = Data->getBufferStart() + strlen(Magic);
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size_t Size = sizeof(ArchiveMemberHeader) +
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ToHeader(Loc)->getSize();
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Child c(this, StringRef(Loc, Size));
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// Skip internals at the beginning of an archive.
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if (skip_internal && isInternalMember(*ToHeader(Loc)))
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return c.getNext();
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return c;
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}
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Archive::child_iterator Archive::end_children() const {
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return Child(this, StringRef(0, 0));
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}
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error_code Archive::Symbol::getName(StringRef &Result) const {
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Result = StringRef(Parent->SymbolTable->getBuffer().begin() + StringIndex);
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return object_error::success;
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}
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error_code Archive::Symbol::getMember(child_iterator &Result) const {
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const char *Buf = Parent->SymbolTable->getBuffer().begin();
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const char *Offsets = Buf + 4;
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uint32_t Offset = 0;
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if (Parent->kind() == K_GNU) {
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Offset = *(reinterpret_cast<const support::ubig32_t*>(Offsets)
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+ SymbolIndex);
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} else if (Parent->kind() == K_BSD) {
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llvm_unreachable("BSD format is not supported");
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} else {
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uint32_t MemberCount = *reinterpret_cast<const support::ulittle32_t*>(Buf);
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// Skip offsets.
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Buf += sizeof(support::ulittle32_t)
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+ (MemberCount * sizeof(support::ulittle32_t));
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uint32_t SymbolCount = *reinterpret_cast<const support::ulittle32_t*>(Buf);
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if (SymbolIndex >= SymbolCount)
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return object_error::parse_failed;
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// Skip SymbolCount to get to the indices table.
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const char *Indices = Buf + sizeof(support::ulittle32_t);
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// Get the index of the offset in the file member offset table for this
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// symbol.
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uint16_t OffsetIndex =
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*(reinterpret_cast<const support::ulittle16_t*>(Indices)
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+ SymbolIndex);
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// Subtract 1 since OffsetIndex is 1 based.
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--OffsetIndex;
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if (OffsetIndex >= MemberCount)
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return object_error::parse_failed;
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Offset = *(reinterpret_cast<const support::ulittle32_t*>(Offsets)
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+ OffsetIndex);
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}
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const char *Loc = Parent->getData().begin() + Offset;
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size_t Size = sizeof(ArchiveMemberHeader) +
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ToHeader(Loc)->getSize();
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Result = Child(Parent, StringRef(Loc, Size));
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return object_error::success;
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}
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Archive::Symbol Archive::Symbol::getNext() const {
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Symbol t(*this);
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// Go to one past next null.
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t.StringIndex =
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Parent->SymbolTable->getBuffer().find('\0', t.StringIndex) + 1;
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++t.SymbolIndex;
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return t;
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}
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Archive::symbol_iterator Archive::begin_symbols() const {
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const char *buf = SymbolTable->getBuffer().begin();
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if (kind() == K_GNU) {
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uint32_t symbol_count = 0;
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symbol_count = *reinterpret_cast<const support::ubig32_t*>(buf);
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buf += sizeof(uint32_t) + (symbol_count * (sizeof(uint32_t)));
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} else if (kind() == K_BSD) {
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llvm_unreachable("BSD archive format is not supported");
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} else {
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uint32_t member_count = 0;
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uint32_t symbol_count = 0;
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member_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
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buf += 4 + (member_count * 4); // Skip offsets.
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symbol_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
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buf += 4 + (symbol_count * 2); // Skip indices.
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}
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uint32_t string_start_offset = buf - SymbolTable->getBuffer().begin();
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return symbol_iterator(Symbol(this, 0, string_start_offset));
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}
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Archive::symbol_iterator Archive::end_symbols() const {
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const char *buf = SymbolTable->getBuffer().begin();
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uint32_t symbol_count = 0;
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if (kind() == K_GNU) {
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symbol_count = *reinterpret_cast<const support::ubig32_t*>(buf);
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buf += sizeof(uint32_t) + (symbol_count * (sizeof(uint32_t)));
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} else if (kind() == K_BSD) {
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llvm_unreachable("BSD archive format is not supported");
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} else {
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uint32_t member_count = 0;
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member_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
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buf += 4 + (member_count * 4); // Skip offsets.
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symbol_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
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}
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return symbol_iterator(
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Symbol(this, symbol_count, 0));
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}
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Archive::child_iterator Archive::findSym(StringRef name) const {
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Archive::symbol_iterator bs = begin_symbols();
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Archive::symbol_iterator es = end_symbols();
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Archive::child_iterator result;
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StringRef symname;
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for (; bs != es; ++bs) {
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if (bs->getName(symname))
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return end_children();
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if (symname == name) {
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if (bs->getMember(result))
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return end_children();
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return result;
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}
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}
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return end_children();
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}
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