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llvm-mirror/lib/Object/Archive.cpp
Rafael Espindola 08aa78de63 Don't own the buffer in object::Binary. 
Owning the buffer is somewhat inflexible. Some Binaries have sub Binaries
(like Archive) and we had to create dummy buffers just to handle that. It is
also a bad fit for IRObjectFile where the Module wants to own the buffer too.

Keeping this ownership would make supporting IR inside native objects
particularly painful.

This patch focuses in lib/Object. If something elsewhere used to own an Binary,
now it also owns a MemoryBuffer.

This patch introduces a few new types.

* MemoryBufferRef. This is just a pair of StringRefs for the data and name.
  This is to MemoryBuffer as StringRef is to std::string.
* OwningBinary. A combination of Binary and a MemoryBuffer. This is needed
  for convenience functions that take a filename and return both the
  buffer and the Binary using that buffer.

The C api now uses OwningBinary to avoid any change in semantics. I will start
a new thread to see if we want to change it and how.

llvm-svn: 216002
2014-08-19 18:44:46 +00:00

497 lines
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//===- Archive.cpp - ar File Format implementation --------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the ArchiveObjectFile class.
//
//===----------------------------------------------------------------------===//
#include "llvm/Object/Archive.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/Twine.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/MemoryBuffer.h"
using namespace llvm;
using namespace object;
static const char *const Magic = "!<arch>\n";
void Archive::anchor() { }
StringRef ArchiveMemberHeader::getName() const {
char EndCond;
if (Name[0] == '/' || Name[0] == '#')
EndCond = ' ';
else
EndCond = '/';
llvm::StringRef::size_type end =
llvm::StringRef(Name, sizeof(Name)).find(EndCond);
if (end == llvm::StringRef::npos)
end = sizeof(Name);
assert(end <= sizeof(Name) && end > 0);
// Don't include the EndCond if there is one.
return llvm::StringRef(Name, end);
}
uint32_t ArchiveMemberHeader::getSize() const {
uint32_t Ret;
if (llvm::StringRef(Size, sizeof(Size)).rtrim(" ").getAsInteger(10, Ret))
llvm_unreachable("Size is not a decimal number.");
return Ret;
}
sys::fs::perms ArchiveMemberHeader::getAccessMode() const {
unsigned Ret;
if (StringRef(AccessMode, sizeof(AccessMode)).rtrim(" ").getAsInteger(8, Ret))
llvm_unreachable("Access mode is not an octal number.");
return static_cast<sys::fs::perms>(Ret);
}
sys::TimeValue ArchiveMemberHeader::getLastModified() const {
unsigned Seconds;
if (StringRef(LastModified, sizeof(LastModified)).rtrim(" ")
.getAsInteger(10, Seconds))
llvm_unreachable("Last modified time not a decimal number.");
sys::TimeValue Ret;
Ret.fromEpochTime(Seconds);
return Ret;
}
unsigned ArchiveMemberHeader::getUID() const {
unsigned Ret;
if (StringRef(UID, sizeof(UID)).rtrim(" ").getAsInteger(10, Ret))
llvm_unreachable("UID time not a decimal number.");
return Ret;
}
unsigned ArchiveMemberHeader::getGID() const {
unsigned Ret;
if (StringRef(GID, sizeof(GID)).rtrim(" ").getAsInteger(10, Ret))
llvm_unreachable("GID time not a decimal number.");
return Ret;
}
Archive::Child::Child(const Archive *Parent, const char *Start)
: Parent(Parent) {
if (!Start)
return;
const ArchiveMemberHeader *Header =
reinterpret_cast<const ArchiveMemberHeader *>(Start);
Data = StringRef(Start, sizeof(ArchiveMemberHeader) + Header->getSize());
// Setup StartOfFile and PaddingBytes.
StartOfFile = sizeof(ArchiveMemberHeader);
// Don't include attached name.
StringRef Name = Header->getName();
if (Name.startswith("#1/")) {
uint64_t NameSize;
if (Name.substr(3).rtrim(" ").getAsInteger(10, NameSize))
llvm_unreachable("Long name length is not an integer");
StartOfFile += NameSize;
}
}
Archive::Child Archive::Child::getNext() const {
size_t SpaceToSkip = Data.size();
// If it's odd, add 1 to make it even.
if (SpaceToSkip & 1)
++SpaceToSkip;
const char *NextLoc = Data.data() + SpaceToSkip;
// Check to see if this is past the end of the archive.
if (NextLoc >= Parent->Data.getBufferEnd())
return Child(Parent, nullptr);
return Child(Parent, NextLoc);
}
ErrorOr<StringRef> Archive::Child::getName() const {
StringRef name = getRawName();
// Check if it's a special name.
if (name[0] == '/') {
if (name.size() == 1) // Linker member.
return name;
if (name.size() == 2 && name[1] == '/') // String table.
return name;
// It's a long name.
// Get the offset.
std::size_t offset;
if (name.substr(1).rtrim(" ").getAsInteger(10, offset))
llvm_unreachable("Long name offset is not an integer");
const char *addr = Parent->StringTable->Data.begin()
+ sizeof(ArchiveMemberHeader)
+ offset;
// Verify it.
if (Parent->StringTable == Parent->child_end()
|| addr < (Parent->StringTable->Data.begin()
+ sizeof(ArchiveMemberHeader))
|| addr > (Parent->StringTable->Data.begin()
+ sizeof(ArchiveMemberHeader)
+ Parent->StringTable->getSize()))
return object_error::parse_failed;
// GNU long file names end with a /.
if (Parent->kind() == K_GNU) {
StringRef::size_type End = StringRef(addr).find('/');
return StringRef(addr, End);
}
return StringRef(addr);
} else if (name.startswith("#1/")) {
uint64_t name_size;
if (name.substr(3).rtrim(" ").getAsInteger(10, name_size))
llvm_unreachable("Long name length is not an ingeter");
return Data.substr(sizeof(ArchiveMemberHeader), name_size)
.rtrim(StringRef("\0", 1));
}
// It's a simple name.
if (name[name.size() - 1] == '/')
return name.substr(0, name.size() - 1);
return name;
}
ErrorOr<MemoryBufferRef> Archive::Child::getMemoryBufferRef() const {
ErrorOr<StringRef> NameOrErr = getName();
if (std::error_code EC = NameOrErr.getError())
return EC;
StringRef Name = NameOrErr.get();
return MemoryBufferRef(getBuffer(), Name);
}
ErrorOr<std::unique_ptr<Binary>>
Archive::Child::getAsBinary(LLVMContext *Context) const {
ErrorOr<MemoryBufferRef> BuffOrErr = getMemoryBufferRef();
if (std::error_code EC = BuffOrErr.getError())
return EC;
return createBinary(BuffOrErr.get(), Context);
}
ErrorOr<std::unique_ptr<Archive>> Archive::create(MemoryBufferRef Source) {
std::error_code EC;
std::unique_ptr<Archive> Ret(new Archive(Source, EC));
if (EC)
return EC;
return std::move(Ret);
}
Archive::Archive(MemoryBufferRef Source, std::error_code &ec)
: Binary(Binary::ID_Archive, Source), SymbolTable(child_end()) {
// Check for sufficient magic.
if (Data.getBufferSize() < 8 ||
StringRef(Data.getBufferStart(), 8) != Magic) {
ec = object_error::invalid_file_type;
return;
}
// Get the special members.
child_iterator i = child_begin(false);
child_iterator e = child_end();
if (i == e) {
ec = object_error::success;
return;
}
StringRef Name = i->getRawName();
// Below is the pattern that is used to figure out the archive format
// GNU archive format
// First member : / (may exist, if it exists, points to the symbol table )
// Second member : // (may exist, if it exists, points to the string table)
// Note : The string table is used if the filename exceeds 15 characters
// BSD archive format
// First member : __.SYMDEF or "__.SYMDEF SORTED" (the symbol table)
// There is no string table, if the filename exceeds 15 characters or has a
// embedded space, the filename has #1/<size>, The size represents the size
// of the filename that needs to be read after the archive header
// COFF archive format
// First member : /
// Second member : / (provides a directory of symbols)
// Third member : // (may exist, if it exists, contains the string table)
// Note: Microsoft PE/COFF Spec 8.3 says that the third member is present
// even if the string table is empty. However, lib.exe does not in fact
// seem to create the third member if there's no member whose filename
// exceeds 15 characters. So the third member is optional.
if (Name == "__.SYMDEF") {
Format = K_BSD;
SymbolTable = i;
++i;
FirstRegular = i;
ec = object_error::success;
return;
}
if (Name.startswith("#1/")) {
Format = K_BSD;
// We know this is BSD, so getName will work since there is no string table.
ErrorOr<StringRef> NameOrErr = i->getName();
ec = NameOrErr.getError();
if (ec)
return;
Name = NameOrErr.get();
if (Name == "__.SYMDEF SORTED") {
SymbolTable = i;
++i;
}
FirstRegular = i;
return;
}
if (Name == "/") {
SymbolTable = i;
++i;
if (i == e) {
ec = object_error::parse_failed;
return;
}
Name = i->getRawName();
}
if (Name == "//") {
Format = K_GNU;
StringTable = i;
++i;
FirstRegular = i;
ec = object_error::success;
return;
}
if (Name[0] != '/') {
Format = K_GNU;
FirstRegular = i;
ec = object_error::success;
return;
}
if (Name != "/") {
ec = object_error::parse_failed;
return;
}
Format = K_COFF;
SymbolTable = i;
++i;
if (i == e) {
FirstRegular = i;
ec = object_error::success;
return;
}
Name = i->getRawName();
if (Name == "//") {
StringTable = i;
++i;
}
FirstRegular = i;
ec = object_error::success;
}
Archive::child_iterator Archive::child_begin(bool SkipInternal) const {
if (Data.getBufferSize() == 8) // empty archive.
return child_end();
if (SkipInternal)
return FirstRegular;
const char *Loc = Data.getBufferStart() + strlen(Magic);
Child c(this, Loc);
return c;
}
Archive::child_iterator Archive::child_end() const {
return Child(this, nullptr);
}
StringRef Archive::Symbol::getName() const {
return Parent->SymbolTable->getBuffer().begin() + StringIndex;
}
ErrorOr<Archive::child_iterator> Archive::Symbol::getMember() const {
const char *Buf = Parent->SymbolTable->getBuffer().begin();
const char *Offsets = Buf + 4;
uint32_t Offset = 0;
if (Parent->kind() == K_GNU) {
Offset = *(reinterpret_cast<const support::ubig32_t*>(Offsets)
+ SymbolIndex);
} else if (Parent->kind() == K_BSD) {
// The SymbolIndex is an index into the ranlib structs that start at
// Offsets (the first uint32_t is the number of bytes of the ranlib
// structs). The ranlib structs are a pair of uint32_t's the first
// being a string table offset and the second being the offset into
// the archive of the member that defines the symbol. Which is what
// is needed here.
Offset = *(reinterpret_cast<const support::ulittle32_t *>(Offsets) +
(SymbolIndex * 2) + 1);
} else {
uint32_t MemberCount = *reinterpret_cast<const support::ulittle32_t*>(Buf);
// Skip offsets.
Buf += sizeof(support::ulittle32_t)
+ (MemberCount * sizeof(support::ulittle32_t));
uint32_t SymbolCount = *reinterpret_cast<const support::ulittle32_t*>(Buf);
if (SymbolIndex >= SymbolCount)
return object_error::parse_failed;
// Skip SymbolCount to get to the indices table.
const char *Indices = Buf + sizeof(support::ulittle32_t);
// Get the index of the offset in the file member offset table for this
// symbol.
uint16_t OffsetIndex =
*(reinterpret_cast<const support::ulittle16_t*>(Indices)
+ SymbolIndex);
// Subtract 1 since OffsetIndex is 1 based.
--OffsetIndex;
if (OffsetIndex >= MemberCount)
return object_error::parse_failed;
Offset = *(reinterpret_cast<const support::ulittle32_t*>(Offsets)
+ OffsetIndex);
}
const char *Loc = Parent->getData().begin() + Offset;
child_iterator Iter(Child(Parent, Loc));
return Iter;
}
Archive::Symbol Archive::Symbol::getNext() const {
Symbol t(*this);
if (Parent->kind() == K_BSD) {
// t.StringIndex is an offset from the start of the __.SYMDEF or
// "__.SYMDEF SORTED" member into the string table for the ranlib
// struct indexed by t.SymbolIndex . To change t.StringIndex to the
// offset in the string table for t.SymbolIndex+1 we subtract the
// its offset from the start of the string table for t.SymbolIndex
// and add the offset of the string table for t.SymbolIndex+1.
// The __.SYMDEF or "__.SYMDEF SORTED" member starts with a uint32_t
// which is the number of bytes of ranlib structs that follow. The ranlib
// structs are a pair of uint32_t's the first being a string table offset
// and the second being the offset into the archive of the member that
// define the symbol. After that the next uint32_t is the byte count of
// the string table followed by the string table.
const char *Buf = Parent->SymbolTable->getBuffer().begin();
uint32_t RanlibCount = 0;
RanlibCount = (*reinterpret_cast<const support::ulittle32_t *>(Buf)) /
(sizeof(uint32_t) * 2);
// If t.SymbolIndex + 1 will be past the count of symbols (the RanlibCount)
// don't change the t.StringIndex as we don't want to reference a ranlib
// past RanlibCount.
if (t.SymbolIndex + 1 < RanlibCount) {
const char *Ranlibs = Buf + 4;
uint32_t CurRanStrx = 0;
uint32_t NextRanStrx = 0;
CurRanStrx = *(reinterpret_cast<const support::ulittle32_t *>(Ranlibs) +
(t.SymbolIndex * 2));
NextRanStrx = *(reinterpret_cast<const support::ulittle32_t *>(Ranlibs) +
((t.SymbolIndex + 1) * 2));
t.StringIndex -= CurRanStrx;
t.StringIndex += NextRanStrx;
}
} else {
// Go to one past next null.
t.StringIndex =
Parent->SymbolTable->getBuffer().find('\0', t.StringIndex) + 1;
}
++t.SymbolIndex;
return t;
}
Archive::symbol_iterator Archive::symbol_begin() const {
if (!hasSymbolTable())
return symbol_iterator(Symbol(this, 0, 0));
const char *buf = SymbolTable->getBuffer().begin();
if (kind() == K_GNU) {
uint32_t symbol_count = 0;
symbol_count = *reinterpret_cast<const support::ubig32_t*>(buf);
buf += sizeof(uint32_t) + (symbol_count * (sizeof(uint32_t)));
} else if (kind() == K_BSD) {
// The __.SYMDEF or "__.SYMDEF SORTED" member starts with a uint32_t
// which is the number of bytes of ranlib structs that follow. The ranlib
// structs are a pair of uint32_t's the first being a string table offset
// and the second being the offset into the archive of the member that
// define the symbol. After that the next uint32_t is the byte count of
// the string table followed by the string table.
uint32_t ranlib_count = 0;
ranlib_count = (*reinterpret_cast<const support::ulittle32_t *>(buf)) /
(sizeof(uint32_t) * 2);
const char *ranlibs = buf + 4;
uint32_t ran_strx = 0;
ran_strx = *(reinterpret_cast<const support::ulittle32_t *>(ranlibs));
buf += sizeof(uint32_t) + (ranlib_count * (2 * (sizeof(uint32_t))));
// Skip the byte count of the string table.
buf += sizeof(uint32_t);
buf += ran_strx;
} else {
uint32_t member_count = 0;
uint32_t symbol_count = 0;
member_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
buf += 4 + (member_count * 4); // Skip offsets.
symbol_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
buf += 4 + (symbol_count * 2); // Skip indices.
}
uint32_t string_start_offset = buf - SymbolTable->getBuffer().begin();
return symbol_iterator(Symbol(this, 0, string_start_offset));
}
Archive::symbol_iterator Archive::symbol_end() const {
if (!hasSymbolTable())
return symbol_iterator(Symbol(this, 0, 0));
const char *buf = SymbolTable->getBuffer().begin();
uint32_t symbol_count = 0;
if (kind() == K_GNU) {
symbol_count = *reinterpret_cast<const support::ubig32_t*>(buf);
} else if (kind() == K_BSD) {
symbol_count = (*reinterpret_cast<const support::ulittle32_t *>(buf)) /
(sizeof(uint32_t) * 2);
} else {
uint32_t member_count = 0;
member_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
buf += 4 + (member_count * 4); // Skip offsets.
symbol_count = *reinterpret_cast<const support::ulittle32_t*>(buf);
}
return symbol_iterator(
Symbol(this, symbol_count, 0));
}
Archive::child_iterator Archive::findSym(StringRef name) const {
Archive::symbol_iterator bs = symbol_begin();
Archive::symbol_iterator es = symbol_end();
for (; bs != es; ++bs) {
StringRef SymName = bs->getName();
if (SymName == name) {
ErrorOr<Archive::child_iterator> ResultOrErr = bs->getMember();
// FIXME: Should we really eat the error?
if (ResultOrErr.getError())
return child_end();
return ResultOrErr.get();
}
}
return child_end();
}
bool Archive::hasSymbolTable() const {
return SymbolTable != child_end();
}
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