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[AIX] Support of Big archive (read)
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Summary:

The patch is based on the EGuesnet's implement of the "Support of Big archive (read)
the first commit of the patch is come from https://reviews.llvm.org/D100651.

the rest of commits of the patch

1  Addressed the comments on the https://reviews.llvm.org/D100651
2  according to https://www.ibm.com/docs/en/aix/7.2?topic=formats-ar-file-format-big
using the "fl_fstmoff" for the first object file number, using "char ar_nxtmem[20]" to get next object file ,
using the "char fl_lstmoff[20]" for the last of the object file will fix the following problems:
   2.1 can not correct reading a archive files which has padding data between too object file
   2.2 can not correct reading a archive files from which some object file has be deleted

3 introduce a new derived class BigArchive for big ar file.

Reviewers: James Henderson
Differential Revision: https://reviews.llvm.org/D111889
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@diggerlin
diggerlin committed Jan 17, 2022
1 parent 875117a commit 3130134
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Showing 9 changed files with 536 additions and 194 deletions.
219 changes: 183 additions & 36 deletions llvm/include/llvm/Object/Archive.h
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Expand Up @@ -32,50 +32,127 @@
namespace llvm {
namespace object {

const char ArchiveMagic[] = "!<arch>\n";
const char ThinArchiveMagic[] = "!<thin>\n";
const char BigArchiveMagic[] = "<bigaf>\n";

class Archive;

class ArchiveMemberHeader {
class AbstractArchiveMemberHeader {
protected:
AbstractArchiveMemberHeader(const Archive *Parent) : Parent(Parent){};

public:
friend class Archive;

ArchiveMemberHeader(Archive const *Parent, const char *RawHeaderPtr,
uint64_t Size, Error *Err);
// ArchiveMemberHeader() = default;
virtual std::unique_ptr<AbstractArchiveMemberHeader> clone() const = 0;
virtual ~AbstractArchiveMemberHeader(){};

/// Get the name without looking up long names.
Expected<StringRef> getRawName() const;
virtual Expected<StringRef> getRawName() const = 0;
virtual StringRef getRawAccessMode() const = 0;
virtual StringRef getRawLastModified() const = 0;
virtual StringRef getRawUID() const = 0;
virtual StringRef getRawGID() const = 0;

/// Get the name looking up long names.
Expected<StringRef> getName(uint64_t Size) const;
virtual Expected<StringRef> getName(uint64_t Size) const = 0;
virtual Expected<uint64_t> getSize() const = 0;
virtual uint64_t getOffset() const = 0;

Expected<uint64_t> getSize() const;
/// Get next file member location.
virtual Expected<const char *> getNextChildLoc() const = 0;
virtual Expected<bool> isThin() const = 0;

Expected<sys::fs::perms> getAccessMode() const;
Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const;
Expected<unsigned> getUID() const;
Expected<unsigned> getGID() const;

/// Returns the size in bytes of the format-defined member header of the
/// concrete archive type.
virtual uint64_t getSizeOf() const = 0;

const Archive *Parent;
};

template <typename T>
class CommonArchiveMemberHeader : public AbstractArchiveMemberHeader {
public:
CommonArchiveMemberHeader(const Archive *Parent, const T *RawHeaderPtr)
: AbstractArchiveMemberHeader(Parent), ArMemHdr(RawHeaderPtr){};
StringRef getRawAccessMode() const override;
StringRef getRawLastModified() const override;
StringRef getRawUID() const override;
StringRef getRawGID() const override;

uint64_t getOffset() const override;
uint64_t getSizeOf() const override { return sizeof(T); }

T const *ArMemHdr;
};

StringRef getRawLastModified() const {
return StringRef(ArMemHdr->LastModified, sizeof(ArMemHdr->LastModified))
.rtrim(' ');
struct UnixArMemHdrType {
char Name[16];
char LastModified[12];
char UID[6];
char GID[6];
char AccessMode[8];
char Size[10]; ///< Size of data, not including header or padding.
char Terminator[2];
};

class ArchiveMemberHeader : public CommonArchiveMemberHeader<UnixArMemHdrType> {
public:
ArchiveMemberHeader(const Archive *Parent, const char *RawHeaderPtr,
uint64_t Size, Error *Err);

std::unique_ptr<AbstractArchiveMemberHeader> clone() const override {
return std::make_unique<ArchiveMemberHeader>(*this);
}

Expected<unsigned> getUID() const;
Expected<unsigned> getGID() const;
Expected<StringRef> getRawName() const override;

// This returns the size of the private struct ArMemHdrType
uint64_t getSizeOf() const { return sizeof(ArMemHdrType); }
Expected<StringRef> getName(uint64_t Size) const override;
Expected<uint64_t> getSize() const override;
Expected<const char *> getNextChildLoc() const override;
Expected<bool> isThin() const override;
};

private:
struct ArMemHdrType {
char Name[16];
char LastModified[12];
char UID[6];
char GID[6];
char AccessMode[8];
char Size[10]; ///< Size of data, not including header or padding.
// File Member Header
struct BigArMemHdrType {
char Size[20]; // File member size in decimal
char NextOffset[20]; // Next member offset in decimal
char PrevOffset[20]; // Previous member offset in decimal
char LastModified[12];
char UID[12];
char GID[12];
char AccessMode[12];
char NameLen[4]; // File member name length in decimal
union {
char Name[2]; // Start of member name
char Terminator[2];
};
Archive const *Parent;
ArMemHdrType const *ArMemHdr;
};

// Define file member header of AIX big archive.
class BigArchiveMemberHeader
: public CommonArchiveMemberHeader<BigArMemHdrType> {

public:
BigArchiveMemberHeader(Archive const *Parent, const char *RawHeaderPtr,
uint64_t Size, Error *Err);
std::unique_ptr<AbstractArchiveMemberHeader> clone() const override {
return std::make_unique<BigArchiveMemberHeader>(*this);
}

Expected<StringRef> getRawName() const override;
Expected<uint64_t> getRawNameSize() const;

Expected<StringRef> getName(uint64_t Size) const override;
Expected<uint64_t> getSize() const override;
Expected<const char *> getNextChildLoc() const override;
Expected<uint64_t> getNextOffset() const;
Expected<bool> isThin() const override { return false; }
};

class Archive : public Binary {
Expand All @@ -84,10 +161,10 @@ class Archive : public Binary {
public:
class Child {
friend Archive;
friend ArchiveMemberHeader;
friend AbstractArchiveMemberHeader;

const Archive *Parent;
ArchiveMemberHeader Header;
std::unique_ptr<AbstractArchiveMemberHeader> Header;
/// Includes header but not padding byte.
StringRef Data;
/// Offset from Data to the start of the file.
Expand All @@ -99,6 +176,44 @@ class Archive : public Binary {
Child(const Archive *Parent, const char *Start, Error *Err);
Child(const Archive *Parent, StringRef Data, uint16_t StartOfFile);

Child(const Child &C)
: Parent(C.Parent), Data(C.Data), StartOfFile(C.StartOfFile) {
if (C.Header)
Header = C.Header->clone();
}

Child(Child &&C) {
Parent = std::move(C.Parent);
Header = std::move(C.Header);
Data = C.Data;
StartOfFile = C.StartOfFile;
}

Child &operator=(Child &&C) noexcept {
if (&C == this)
return *this;

Parent = std::move(C.Parent);
Header = std::move(C.Header);
Data = C.Data;
StartOfFile = C.StartOfFile;

return *this;
}

Child &operator=(const Child &C) {
if (&C == this)
return *this;

Parent = C.Parent;
if (C.Header)
Header = C.Header->clone();
Data = C.Data;
StartOfFile = C.StartOfFile;

return *this;
}

bool operator==(const Child &other) const {
assert(!Parent || !other.Parent || Parent == other.Parent);
return Data.begin() == other.Data.begin();
Expand All @@ -109,19 +224,21 @@ class Archive : public Binary {

Expected<StringRef> getName() const;
Expected<std::string> getFullName() const;
Expected<StringRef> getRawName() const { return Header.getRawName(); }
Expected<StringRef> getRawName() const { return Header->getRawName(); }

Expected<sys::TimePoint<std::chrono::seconds>> getLastModified() const {
return Header.getLastModified();
return Header->getLastModified();
}

StringRef getRawLastModified() const { return Header.getRawLastModified(); }
StringRef getRawLastModified() const {
return Header->getRawLastModified();
}

Expected<unsigned> getUID() const { return Header.getUID(); }
Expected<unsigned> getGID() const { return Header.getGID(); }
Expected<unsigned> getUID() const { return Header->getUID(); }
Expected<unsigned> getGID() const { return Header->getGID(); }

Expected<sys::fs::perms> getAccessMode() const {
return Header.getAccessMode();
return Header->getAccessMode();
}

/// \return the size of the archive member without the header or padding.
Expand Down Expand Up @@ -218,7 +335,7 @@ class Archive : public Binary {
/// Size field is 10 decimal digits long
static const uint64_t MaxMemberSize = 9999999999;

enum Kind { K_GNU, K_GNU64, K_BSD, K_DARWIN, K_DARWIN64, K_COFF };
enum Kind { K_GNU, K_GNU64, K_BSD, K_DARWIN, K_DARWIN64, K_COFF, K_AIXBIG };

Kind kind() const { return (Kind)Format; }
bool isThin() const { return IsThin; }
Expand All @@ -236,7 +353,6 @@ class Archive : public Binary {
return make_range(symbol_begin(), symbol_end());
}

// Cast methods.
static bool classof(Binary const *v) { return v->isArchive(); }

// check if a symbol is in the archive
Expand All @@ -247,24 +363,55 @@ class Archive : public Binary {
StringRef getSymbolTable() const { return SymbolTable; }
StringRef getStringTable() const { return StringTable; }
uint32_t getNumberOfSymbols() const;
virtual uint64_t getFirstChildOffset() const { return getArchiveMagicLen(); }

std::vector<std::unique_ptr<MemoryBuffer>> takeThinBuffers() {
return std::move(ThinBuffers);
}

std::unique_ptr<AbstractArchiveMemberHeader>
createArchiveMemberHeader(const char *RawHeaderPtr, uint64_t Size,
Error *Err) const;

protected:
uint64_t getArchiveMagicLen() const;
void setFirstRegular(const Child &C);

private:
StringRef SymbolTable;
StringRef StringTable;

StringRef FirstRegularData;
uint16_t FirstRegularStartOfFile = -1;
void setFirstRegular(const Child &C);

unsigned Format : 3;
unsigned IsThin : 1;
mutable std::vector<std::unique_ptr<MemoryBuffer>> ThinBuffers;
};

class BigArchive : public Archive {
/// Fixed-Length Header.
struct FixLenHdr {
char Magic[sizeof(BigArchiveMagic) - 1]; ///< Big archive magic string.
char MemOffset[20]; ///< Offset to member table.
char GlobSymOffset[20]; ///< Offset to global symbol table.
char
GlobSym64Offset[20]; ///< Offset global symbol table for 64-bit objects.
char FirstChildOffset[20]; ///< Offset to first archive member.
char LastChildOffset[20]; ///< Offset to last archive member.
char FreeOffset[20]; ///< Offset to first mem on free list.
};

const FixLenHdr *ArFixLenHdr;
uint64_t FirstChildOffset = 0;
uint64_t LastChildOffset = 0;

public:
BigArchive(MemoryBufferRef Source, Error &Err);
uint64_t getFirstChildOffset() const override { return FirstChildOffset; }
uint64_t getLastChildOffset() const { return LastChildOffset; }
};

} // end namespace object
} // end namespace llvm

Expand Down

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