407 lines
11 KiB
C
407 lines
11 KiB
C
|
/* LTO routines for COFF object files.
|
||
|
Copyright 2009 Free Software Foundation, Inc.
|
||
|
Contributed by Dave Korn.
|
||
|
|
||
|
This file is part of GCC.
|
||
|
|
||
|
GCC is free software; you can redistribute it and/or modify it under
|
||
|
the terms of the GNU General Public License as published by the Free
|
||
|
Software Foundation; either version 3, or (at your option) any later
|
||
|
version.
|
||
|
|
||
|
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
|
||
|
WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
||
|
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
||
|
for more details.
|
||
|
|
||
|
You should have received a copy of the GNU General Public License
|
||
|
along with GCC; see the file COPYING3. If not see
|
||
|
<http://www.gnu.org/licenses/>. */
|
||
|
|
||
|
#ifndef LTO_COFF_H
|
||
|
#define LTO_COFF_H
|
||
|
|
||
|
/* Rather than implementing a libcoff to match libelf, or attempting to
|
||
|
integrate libbfd into GCC, this file is a self-contained (and very
|
||
|
minimal) COFF format object file reader/writer. The generated files
|
||
|
will contain a COFF header, a number of COFF section headers, the
|
||
|
section data itself, and a trailing string table for section names. */
|
||
|
|
||
|
/* Alignment of sections in a COFF object file.
|
||
|
|
||
|
The LTO writer uses zlib compression on the data that it streams into
|
||
|
LTO sections in the output object file. Because these streams don't
|
||
|
have any embedded size information, the section in the object file must
|
||
|
be exactly sized to the data emitted; any trailing padding bytes will
|
||
|
be interpreted as partial and/or corrupt compressed data.
|
||
|
|
||
|
This is easy enough to do on COFF targets (with binutils 2.20.1 or
|
||
|
above) because we can specify 1-byte alignment for the LTO sections.
|
||
|
They are then emitted precisely-sized and byte-packed into the object
|
||
|
and the reader is happy when it parses them later. This is currently
|
||
|
implemented in the x86/windows backed in i386_pe_asm_named_section()
|
||
|
in config/i386/winnt.c by detecting the LTO section name prefix,
|
||
|
|
||
|
That would be sufficient, but for one thing. At the start of the LTO
|
||
|
data is a header struct with (currently) a couple of version numbers and
|
||
|
some type info; see struct lto_header in lto-streamer.h. If the sections
|
||
|
are byte-packed, this header will not necessarily be correctly-aligned
|
||
|
when it is read back into memory.
|
||
|
|
||
|
On x86 targets, which are currently the only LTO-COFF targets, misaligned
|
||
|
memory accesses aren't problematic (okay, inefficient, but not worth
|
||
|
worrying about two half-word memory reads per section in the context of
|
||
|
everything else the compiler has to do at the time!), but RISC targets may
|
||
|
fail on trying to access the header struct. In this case, it will be
|
||
|
necessary to enable (preferably in a target-dependent fashion, but a few
|
||
|
bytes of padding are hardly an important issue if it comes down to it) the
|
||
|
COFF_ALIGNMENT macros below.
|
||
|
|
||
|
As currently implemented, this will emit padding to the necessary number
|
||
|
of bytes after each LTO section. These bytes will constitute 'gaps' in
|
||
|
the object file structure, as they won't be covered by any section header.
|
||
|
This hasn't yet been tested, because no such RISC LTO-COFF target yet
|
||
|
exists. If it causes problems further down the toolchain, it will be
|
||
|
necessary to adapt the code to emit additional section headers for these
|
||
|
padding bytes, but the odds are that it will "just work".
|
||
|
|
||
|
*/
|
||
|
|
||
|
#if 0
|
||
|
#define COFF_ALIGNMENT (4)
|
||
|
#define COFF_ALIGNMENTM1 (COFF_ALIGNMENT - 1)
|
||
|
#define COFF_ALIGN(x) (((x) + COFF_ALIGNMENTM1) & ~COFF_ALIGNMENTM1)
|
||
|
#else
|
||
|
#define COFF_ALIGNMENT (1)
|
||
|
#define COFF_ALIGN(x) (x)
|
||
|
#endif
|
||
|
|
||
|
/* COFF header machine codes. */
|
||
|
|
||
|
#define IMAGE_FILE_MACHINE_I386 (0x014c)
|
||
|
|
||
|
/* Known header magics for validation, as an array initialiser. */
|
||
|
|
||
|
#define COFF_KNOWN_MACHINES \
|
||
|
{ IMAGE_FILE_MACHINE_I386/*, ... add more here when working. */ }
|
||
|
|
||
|
/* COFF object file header, section and symbol flags and types. These are
|
||
|
currently specific to PE-COFF, which is the only LTO-COFF format at the
|
||
|
time of writing. Maintainers adding support for new COFF formats will
|
||
|
need to make these into target macros of some kind. */
|
||
|
|
||
|
/* COFF header characteristics. */
|
||
|
|
||
|
#define IMAGE_FILE_EXECUTABLE_IMAGE (1 << 1)
|
||
|
#define IMAGE_FILE_32BIT_MACHINE (1 << 8)
|
||
|
#define IMAGE_FILE_SYSTEM (1 << 12)
|
||
|
#define IMAGE_FILE_DLL (1 << 13)
|
||
|
|
||
|
/* Desired characteristics (for validation). */
|
||
|
|
||
|
#define COFF_CHARACTERISTICS \
|
||
|
(IMAGE_FILE_32BIT_MACHINE)
|
||
|
|
||
|
/* Unwanted characteristics (for validation). */
|
||
|
|
||
|
#define COFF_NOT_CHARACTERISTICS \
|
||
|
(IMAGE_FILE_EXECUTABLE_IMAGE | IMAGE_FILE_SYSTEM | IMAGE_FILE_DLL)
|
||
|
|
||
|
/* Section flags. LTO emits byte-aligned read-only loadable data sections. */
|
||
|
|
||
|
#define IMAGE_SCN_CNT_INITIALIZED_DATA (1 << 6)
|
||
|
#define IMAGE_SCN_CNT_UNINITIALIZED_DATA (1 << 7)
|
||
|
#define IMAGE_SCN_ALIGN_1BYTES (0x1 << 20)
|
||
|
#define IMAGE_SCN_MEM_DISCARDABLE (1 << 25)
|
||
|
#define IMAGE_SCN_MEM_SHARED (1 << 28)
|
||
|
#define IMAGE_SCN_MEM_READ (1 << 30)
|
||
|
|
||
|
#define COFF_SECTION_CHARACTERISTICS \
|
||
|
(IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_ALIGN_1BYTES | \
|
||
|
IMAGE_SCN_MEM_DISCARDABLE | IMAGE_SCN_MEM_SHARED | IMAGE_SCN_MEM_READ)
|
||
|
|
||
|
/* Symbol-related constants. */
|
||
|
|
||
|
#define IMAGE_SYM_DEBUG (-2)
|
||
|
#define IMAGE_SYM_TYPE_NULL (0)
|
||
|
#define IMAGE_SYM_DTYPE_NULL (0)
|
||
|
#define IMAGE_SYM_CLASS_STATIC (3)
|
||
|
#define IMAGE_SYM_CLASS_FILE (103)
|
||
|
|
||
|
#define IMAGE_SYM_TYPE \
|
||
|
((IMAGE_SYM_DTYPE_NULL << 4) | IMAGE_SYM_TYPE_NULL)
|
||
|
|
||
|
/* Size of a COFF symbol in bytes. */
|
||
|
|
||
|
#define COFF_SYMBOL_SIZE (18)
|
||
|
|
||
|
/* On-disk file structures. */
|
||
|
|
||
|
struct Coff_header
|
||
|
{
|
||
|
unsigned char Machine[2];
|
||
|
unsigned char NumberOfSections[2];
|
||
|
unsigned char TimeDateStamp[4];
|
||
|
unsigned char PointerToSymbolTable[4];
|
||
|
unsigned char NumberOfSymbols[4];
|
||
|
unsigned char SizeOfOptionalHeader[2];
|
||
|
unsigned char Characteristics[2];
|
||
|
};
|
||
|
typedef struct Coff_header Coff_header;
|
||
|
|
||
|
struct Coff_section
|
||
|
{
|
||
|
unsigned char Name[8];
|
||
|
unsigned char VirtualSize[4];
|
||
|
unsigned char VirtualAddress[4];
|
||
|
unsigned char SizeOfRawData[4];
|
||
|
unsigned char PointerToRawData[4];
|
||
|
unsigned char PointerToRelocations[4];
|
||
|
unsigned char PointerToLinenumbers[4];
|
||
|
unsigned char NumberOfRelocations[2];
|
||
|
unsigned char NumberOfLinenumbers[2];
|
||
|
unsigned char Characteristics[4];
|
||
|
};
|
||
|
typedef struct Coff_section Coff_section;
|
||
|
|
||
|
struct Coff_symbol
|
||
|
{
|
||
|
unsigned char Name[8];
|
||
|
unsigned char Value[4];
|
||
|
unsigned char SectionNumber[2];
|
||
|
unsigned char Type[2];
|
||
|
unsigned char StorageClass[1];
|
||
|
unsigned char NumberOfAuxSymbols[1];
|
||
|
};
|
||
|
typedef struct Coff_symbol Coff_symbol;
|
||
|
|
||
|
struct Coff_aux_sym_file
|
||
|
{
|
||
|
unsigned char FileName[18];
|
||
|
};
|
||
|
typedef struct Coff_aux_sym_file Coff_aux_sym_file;
|
||
|
|
||
|
struct Coff_aux_sym_section
|
||
|
{
|
||
|
unsigned char Length[4];
|
||
|
unsigned char NumberOfRelocations[2];
|
||
|
unsigned char NumberOfLineNumbers[2];
|
||
|
unsigned char Checksum[4];
|
||
|
unsigned char Number[2];
|
||
|
unsigned char Selection[1];
|
||
|
unsigned char Unused[3];
|
||
|
};
|
||
|
typedef struct Coff_aux_sym_section Coff_aux_sym_section;
|
||
|
|
||
|
/* Accessor macros for the above structures. */
|
||
|
|
||
|
#define COFF_GET(struc,memb) \
|
||
|
((COFFENDIAN ? get_be : get_le) (&(struc)->memb[0], sizeof ((struc)->memb)))
|
||
|
|
||
|
#define COFF_PUT(struc,memb,val) \
|
||
|
((COFFENDIAN ? put_be : put_le) (&(struc)->memb[0], sizeof ((struc)->memb), val))
|
||
|
|
||
|
#define COFF_PUT_NDXSZ(struc,memb,val,ndx,sz) \
|
||
|
((COFFENDIAN ? put_be : put_le) (&(struc)->memb[ndx], sz, val))
|
||
|
|
||
|
/* In-memory file structures. */
|
||
|
|
||
|
/* Forward declared structs. */
|
||
|
|
||
|
struct lto_coff_data;
|
||
|
struct lto_coff_section;
|
||
|
struct lto_coff_file;
|
||
|
|
||
|
/* Section data in output files is made of these. */
|
||
|
|
||
|
struct lto_coff_data
|
||
|
{
|
||
|
/* Pointer to data block. */
|
||
|
void *d_buf;
|
||
|
|
||
|
/* Size of data block. */
|
||
|
ssize_t d_size;
|
||
|
|
||
|
/* Next data block for this section. */
|
||
|
struct lto_coff_data *next;
|
||
|
};
|
||
|
typedef struct lto_coff_data lto_coff_data;
|
||
|
|
||
|
/* This struct tracks the data for a section. */
|
||
|
|
||
|
struct lto_coff_section
|
||
|
{
|
||
|
/* Singly-linked list of section's data blocks. */
|
||
|
lto_coff_data *data_chain;
|
||
|
|
||
|
/* Offset in string table of name. */
|
||
|
size_t strtab_offs;
|
||
|
|
||
|
/* Section type: 0 = real, 1 = dummy. */
|
||
|
size_t type;
|
||
|
|
||
|
/* Section name. */
|
||
|
const char *name;
|
||
|
|
||
|
#if COFF_ALIGNMENT > 1
|
||
|
/* Number of trailing padding bytes needed. */
|
||
|
ssize_t pad_needed;
|
||
|
#endif
|
||
|
|
||
|
/* Raw section header data. */
|
||
|
Coff_section coffsec;
|
||
|
|
||
|
/* Next section for this file. */
|
||
|
struct lto_coff_section *next;
|
||
|
};
|
||
|
typedef struct lto_coff_section lto_coff_section;
|
||
|
|
||
|
/* A COFF file. */
|
||
|
|
||
|
struct lto_coff_file
|
||
|
{
|
||
|
/* The base information. */
|
||
|
lto_file base;
|
||
|
|
||
|
/* Common file members: */
|
||
|
|
||
|
/* The system file descriptor for the file. */
|
||
|
int fd;
|
||
|
|
||
|
/* The file's overall header. */
|
||
|
Coff_header coffhdr;
|
||
|
|
||
|
/* All sections in a singly-linked list. */
|
||
|
lto_coff_section *section_chain;
|
||
|
|
||
|
/* Readable file members: */
|
||
|
|
||
|
/* File total size. */
|
||
|
off_t file_size;
|
||
|
|
||
|
/* String table file offset, relative to base.offset. */
|
||
|
off_t strtab_offs;
|
||
|
|
||
|
/* Writable file members: */
|
||
|
|
||
|
/* The currently active section. */
|
||
|
lto_coff_section *scn;
|
||
|
|
||
|
/* The output stream for section header names. */
|
||
|
struct lto_output_stream *shstrtab_stream;
|
||
|
|
||
|
/* Linked list of data which must be freed *after* the file has been
|
||
|
closed. This is an annoying limitation of libelf. Which has been
|
||
|
faithfully reproduced here. */
|
||
|
struct lto_char_ptr_base *data;
|
||
|
};
|
||
|
typedef struct lto_coff_file lto_coff_file;
|
||
|
|
||
|
/* Data hunk iterator. */
|
||
|
|
||
|
#define COFF_FOR_ALL_DATA(sec,var) \
|
||
|
for (var = sec->data_chain; var; var = var->next)
|
||
|
|
||
|
/* Section list iterator. */
|
||
|
|
||
|
#define COFF_FOR_ALL_SECTIONS(file,var) \
|
||
|
for (var = file->section_chain; var; var = var->next)
|
||
|
|
||
|
/* Very simple endian-ness layer. */
|
||
|
|
||
|
#ifndef COFFENDIAN
|
||
|
#define COFFENDIAN (BYTES_BIG_ENDIAN)
|
||
|
#endif
|
||
|
|
||
|
static inline unsigned int
|
||
|
get_2_le (const unsigned char *ptr)
|
||
|
{
|
||
|
return ptr[0] | (ptr[1] << 8);
|
||
|
}
|
||
|
|
||
|
static inline unsigned int
|
||
|
get_4_le (const unsigned char *ptr)
|
||
|
{
|
||
|
return ptr[0] | (ptr[1] << 8) | (ptr[2] << 16) | (ptr[3] << 24);
|
||
|
}
|
||
|
|
||
|
static inline unsigned int
|
||
|
get_2_be (const unsigned char *ptr)
|
||
|
{
|
||
|
return ptr[1] | (ptr[0] << 8);
|
||
|
}
|
||
|
|
||
|
static inline unsigned int
|
||
|
get_4_be (const unsigned char *ptr)
|
||
|
{
|
||
|
return ptr[3] | (ptr[2] << 8) | (ptr[1] << 16) | (ptr[0] << 24);
|
||
|
}
|
||
|
|
||
|
static inline unsigned int
|
||
|
get_be (const unsigned char *ptr, size_t size)
|
||
|
{
|
||
|
gcc_assert (size == 4 || size == 2);
|
||
|
return (size == 2) ? get_2_be (ptr) : get_4_be (ptr);
|
||
|
}
|
||
|
|
||
|
static inline unsigned int
|
||
|
get_le (const unsigned char *ptr, size_t size)
|
||
|
{
|
||
|
gcc_assert (size == 4 || size == 2);
|
||
|
return (size == 2) ? get_2_le (ptr) : get_4_le (ptr);
|
||
|
}
|
||
|
|
||
|
static inline void
|
||
|
put_2_le (unsigned char *ptr, unsigned int data)
|
||
|
{
|
||
|
ptr[0] = data & 0xff;
|
||
|
ptr[1] = (data >> 8) & 0xff;
|
||
|
}
|
||
|
|
||
|
static inline void
|
||
|
put_4_le (unsigned char *ptr, unsigned int data)
|
||
|
{
|
||
|
ptr[0] = data & 0xff;
|
||
|
ptr[1] = (data >> 8) & 0xff;
|
||
|
ptr[2] = (data >> 16) & 0xff;
|
||
|
ptr[3] = (data >> 24) & 0xff;
|
||
|
}
|
||
|
|
||
|
static inline void
|
||
|
put_2_be (unsigned char *ptr, unsigned int data)
|
||
|
{
|
||
|
ptr[1] = data & 0xff;
|
||
|
ptr[0] = (data >> 8) & 0xff;
|
||
|
}
|
||
|
|
||
|
static inline void
|
||
|
put_4_be (unsigned char *ptr, unsigned int data)
|
||
|
{
|
||
|
ptr[3] = data & 0xff;
|
||
|
ptr[2] = (data >> 8) & 0xff;
|
||
|
ptr[1] = (data >> 16) & 0xff;
|
||
|
ptr[0] = (data >> 24) & 0xff;
|
||
|
}
|
||
|
|
||
|
static inline void
|
||
|
put_le (unsigned char *ptr, size_t size, unsigned int data)
|
||
|
{
|
||
|
gcc_assert (size == 4 || size == 2);
|
||
|
(void) (size == 2 ? put_2_le : put_4_le) (ptr, data);
|
||
|
}
|
||
|
|
||
|
static inline void
|
||
|
put_be (unsigned char *ptr, size_t size, unsigned int data)
|
||
|
{
|
||
|
gcc_assert (size == 4 || size == 2);
|
||
|
(void) (size == 2 ? put_2_be : put_4_be) (ptr, data);
|
||
|
}
|
||
|
|
||
|
/* We use this for putting the string table size. */
|
||
|
|
||
|
#define COFF_PUT4(ptr, data) \
|
||
|
((COFFENDIAN ? put_4_be : put_4_le) (ptr, data))
|
||
|
|
||
|
|
||
|
#endif /* LTO_COFF_H */
|