diff options
Diffstat (limited to 'bfd/coffcode.h')
| -rw-r--r-- | bfd/coffcode.h | 160 |
1 files changed, 130 insertions, 30 deletions
diff --git a/bfd/coffcode.h b/bfd/coffcode.h index db0b2e9..cfa1a40 100644 --- a/bfd/coffcode.h +++ b/bfd/coffcode.h @@ -1,6 +1,6 @@ /* Support for the generic parts of most COFF variants, for BFD. Copyright 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, - 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 + 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. Written by Cygnus Support. @@ -109,6 +109,60 @@ SUBSUBSECTION target. SUBSUBSECTION + Coff long section names + + In the standard Coff object format, section names are limited to + the eight bytes available in the @code{s_name} field of the + @code{SCNHDR} section header structure. The format requires the + field to be NUL-padded, but not necessarily NUL-terminated, so + the longest section names permitted are a full eight characters. + + The Microsoft PE variants of the Coff object file format add + an extension to support the use of long section names. This + extension is defined in section 4 of the Microsoft PE/COFF + specification (rev 8.1). If a section name is too long to fit + into the section header's @code{s_name} field, it is instead + placed into the string table, and the @code{s_name} field is + filled with a slash ("/") followed by the ASCII decimal + representation of the offset of the full name relative to the + string table base. + + Note that this implies that the extension can only be used in object + files, as executables do not contain a string table. The standard + specifies that long section names from objects emitted into executable + images are to be truncated. + + However, as a GNU extension, BFD can generate executable images + that contain a string table and long section names. This + would appear to be technically valid, as the standard only says + that Coff debugging information is deprecated, not forbidden, + and in practice it works, although some tools that parse PE files + expecting the MS standard format may become confused; @file{PEview} is + one known example. + + The functionality is supported in BFD by code implemented under + the control of the macro @code{COFF_LONG_SECTION_NAMES}. If not + defined, the format does not support long section names in any way. + If defined, it is used to initialise a flag, + @code{_bfd_coff_long_section_names}, and a hook function pointer, + @code{_bfd_coff_set_long_section_names}, in the Coff backend data + structure. The flag controls the generation of long section names + in output BFDs at runtime; if it is false, as it will be by default + when generating an executable image, long section names are truncated; + if true, the long section names extension is employed. The hook + points to a function that allows the value of the flag to be altered + at runtime, on formats that support long section names at all; on + other formats it points to a stub that returns an error indication. + + If @code{COFF_LONG_SECTION_NAMES} is simply defined (blank), or is + defined to the value "1", then long section names are enabled by + default; if it is defined to the value zero, they are disabled by + default (but still accepted in input BFDs). The header @file{coffcode.h} + defines a macro, @code{COFF_DEFAULT_LONG_SECTION_NAMES}, which is + used in the backends to initialise the backend data structure fields + appropriately; see the comments for further detail. + +SUBSUBSECTION Bit twiddling Each flavour of coff supported in BFD has its own header file @@ -310,6 +364,40 @@ CODE_FRAGMENT #define DOT_DEBUG ".debug" #define GNU_LINKONCE_WI ".gnu.linkonce.wi." +#if defined (COFF_LONG_SECTION_NAMES) +/* Needed to expand the inputs to BLANKOR1TOODD. */ +#define COFFLONGSECTIONCATHELPER(x,y) x ## y +/* If the input macro Y is blank or '1', return an odd number; if it is + '0', return an even number. Result undefined in all other cases. */ +#define BLANKOR1TOODD(y) COFFLONGSECTIONCATHELPER(1,y) +/* Defined to numerical 0 or 1 according to whether generation of long + section names is disabled or enabled by default. */ +#define COFF_ENABLE_LONG_SECTION_NAMES (BLANKOR1TOODD(COFF_LONG_SECTION_NAMES) & 1) +/* Where long section names are supported, we allow them to be enabled + and disabled at runtime, so select an appropriate hook function for + _bfd_coff_set_long_section_names. */ +#define COFF_LONG_SECTION_NAMES_SETTER bfd_coff_set_long_section_names_allowed +#else /* !defined (COFF_LONG_SECTION_NAMES) */ +/* If long section names are not supported, this stub disallows any + attempt to enable them at run-time. */ +#define COFF_LONG_SECTION_NAMES_SETTER bfd_coff_set_long_section_names_disallowed +#endif /* defined (COFF_LONG_SECTION_NAMES) */ + +/* Define a macro that can be used to initialise both the fields relating + to long section names in the backend data struct simultaneously. */ +#if COFF_ENABLE_LONG_SECTION_NAMES +#define COFF_DEFAULT_LONG_SECTION_NAMES (TRUE), COFF_LONG_SECTION_NAMES_SETTER +#else /* !COFF_ENABLE_LONG_SECTION_NAMES */ +#define COFF_DEFAULT_LONG_SECTION_NAMES (FALSE), COFF_LONG_SECTION_NAMES_SETTER +#endif /* COFF_ENABLE_LONG_SECTION_NAMES */ + +#if defined (COFF_LONG_SECTION_NAMES) +static bfd_boolean bfd_coff_set_long_section_names_allowed + (bfd *, int); +#else /* !defined (COFF_LONG_SECTION_NAMES) */ +static bfd_boolean bfd_coff_set_long_section_names_disallowed + (bfd *, int); +#endif /* defined (COFF_LONG_SECTION_NAMES) */ static long sec_to_styp_flags (const char *, flagword); static bfd_boolean styp_to_sec_flags @@ -372,6 +460,23 @@ static bfd_boolean ticoff1_bad_format_hook /* void warning(); */ +#if defined (COFF_LONG_SECTION_NAMES) +static bfd_boolean +bfd_coff_set_long_section_names_allowed (bfd *abfd, int enable) +{ + coff_backend_info (abfd)->_bfd_coff_long_section_names = enable; + return TRUE; +} +#else /* !defined (COFF_LONG_SECTION_NAMES) */ +static bfd_boolean +bfd_coff_set_long_section_names_disallowed (bfd *abfd, int enable) +{ + (void) abfd; + (void) enable; + return FALSE; +} +#endif /* defined (COFF_LONG_SECTION_NAMES) */ + /* Return a word with STYP_* (scnhdr.s_flags) flags set to represent the incoming SEC_* flags. The inverse of this function is styp_to_sec_flags(). NOTE: If you add to/change this routine, you @@ -1214,7 +1319,11 @@ Special entry points for gdb to swap in coff symbol table parts: . unsigned int _bfd_linesz; . unsigned int _bfd_filnmlen; . bfd_boolean _bfd_coff_long_filenames; +. . bfd_boolean _bfd_coff_long_section_names; +. bfd_boolean (*_bfd_coff_set_long_section_names) +. (bfd *, int); +. . unsigned int _bfd_coff_default_section_alignment_power; . bfd_boolean _bfd_coff_force_symnames_in_strings; . unsigned int _bfd_coff_debug_string_prefix_length; @@ -1351,6 +1460,8 @@ Special entry points for gdb to swap in coff symbol table parts: . (coff_backend_info (abfd)->_bfd_coff_long_filenames) .#define bfd_coff_long_section_names(abfd) \ . (coff_backend_info (abfd)->_bfd_coff_long_section_names) +.#define bfd_coff_set_long_section_names(abfd, enable) \ +. ((coff_backend_info (abfd)->_bfd_coff_set_long_section_names) (abfd, enable)) .#define bfd_coff_default_section_alignment_power(abfd) \ . (coff_backend_info (abfd)->_bfd_coff_default_section_alignment_power) .#define bfd_coff_swap_filehdr_in(abfd, i,o) \ @@ -3511,18 +3622,19 @@ coff_write_object_contents (bfd * abfd) #ifdef COFF_LONG_SECTION_NAMES /* Handle long section names as in PE. This must be compatible with the code in coff_write_symbols and _bfd_coff_final_link. */ - { - size_t len; + if (bfd_coff_long_section_names (abfd)) + { + size_t len; - len = strlen (current->name); - if (len > SCNNMLEN) - { - memset (section.s_name, 0, SCNNMLEN); - sprintf (section.s_name, "/%lu", (unsigned long) string_size); - string_size += len + 1; - long_section_names = TRUE; - } - } + len = strlen (current->name); + if (len > SCNNMLEN) + { + memset (section.s_name, 0, SCNNMLEN); + sprintf (section.s_name, "/%lu", (unsigned long) string_size); + string_size += len + 1; + long_section_names = TRUE; + } + } #endif #ifdef _LIB @@ -5246,7 +5358,7 @@ coff_final_link_postscript (bfd * abfd ATTRIBUTE_UNUSED, #define coff_SWAP_scnhdr_in coff_swap_scnhdr_in #endif -static const bfd_coff_backend_data bfd_coff_std_swap_table ATTRIBUTE_UNUSED = +static bfd_coff_backend_data bfd_coff_std_swap_table ATTRIBUTE_UNUSED = { coff_SWAP_aux_in, coff_SWAP_sym_in, coff_SWAP_lineno_in, coff_SWAP_aux_out, coff_SWAP_sym_out, @@ -5259,11 +5371,7 @@ static const bfd_coff_backend_data bfd_coff_std_swap_table ATTRIBUTE_UNUSED = #else FALSE, #endif -#ifdef COFF_LONG_SECTION_NAMES - TRUE, -#else - FALSE, -#endif + COFF_DEFAULT_LONG_SECTION_NAMES, COFF_DEFAULT_SECTION_ALIGNMENT_POWER, #ifdef COFF_FORCE_SYMBOLS_IN_STRINGS TRUE, @@ -5290,7 +5398,7 @@ static const bfd_coff_backend_data bfd_coff_std_swap_table ATTRIBUTE_UNUSED = #ifdef TICOFF /* COFF0 differs in file/section header size and relocation entry size. */ -static const bfd_coff_backend_data ticoff0_swap_table = +static bfd_coff_backend_data ticoff0_swap_table = { coff_SWAP_aux_in, coff_SWAP_sym_in, coff_SWAP_lineno_in, coff_SWAP_aux_out, coff_SWAP_sym_out, @@ -5303,11 +5411,7 @@ static const bfd_coff_backend_data ticoff0_swap_table = #else FALSE, #endif -#ifdef COFF_LONG_SECTION_NAMES - TRUE, -#else - FALSE, -#endif + COFF_DEFAULT_LONG_SECTION_NAMES, COFF_DEFAULT_SECTION_ALIGNMENT_POWER, #ifdef COFF_FORCE_SYMBOLS_IN_STRINGS TRUE, @@ -5335,7 +5439,7 @@ static const bfd_coff_backend_data ticoff0_swap_table = #ifdef TICOFF /* COFF1 differs in section header size. */ -static const bfd_coff_backend_data ticoff1_swap_table = +static bfd_coff_backend_data ticoff1_swap_table = { coff_SWAP_aux_in, coff_SWAP_sym_in, coff_SWAP_lineno_in, coff_SWAP_aux_out, coff_SWAP_sym_out, @@ -5348,11 +5452,7 @@ static const bfd_coff_backend_data ticoff1_swap_table = #else FALSE, #endif -#ifdef COFF_LONG_SECTION_NAMES - TRUE, -#else - FALSE, -#endif + COFF_DEFAULT_LONG_SECTION_NAMES, COFF_DEFAULT_SECTION_ALIGNMENT_POWER, #ifdef COFF_FORCE_SYMBOLS_IN_STRINGS TRUE, |