\input texinfo
-@c Copyright 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
-@c 2001, 2002, 2003, 2004, 2005
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1991-2018 Free Software Foundation, Inc.
@setfilename internals.info
@node Top
@top Assembler Internals
Whether the symbol is an MRI common symbol created by the @code{COMMON}
pseudo-op when assembling in MRI mode.
+@item sy_volatile
+Whether the symbol can be re-defined.
+
+@item sy_forward_ref
+Whether the symbol's value must only be evaluated upon use.
+
+@item sy_weakrefr
+Whether the symbol is a @code{weakref} alias to another symbol.
+
+@item sy_weakrefd
+Whether the symbol is or was referenced by one or more @code{weakref} aliases,
+and has not had any direct references.
+
@item bsym
This points to the BFD @code{asymbol} that
will be used in writing the object file.
@cindex S_IS_EXTERNAL
Return non-zero if the symbol is externally visible.
-@item S_IS_EXTERN
-@cindex S_IS_EXTERN
-A synonym for @code{S_IS_EXTERNAL}. Don't use it.
-
@item S_IS_WEAK
@cindex S_IS_WEAK
-Return non-zero if the symbol is weak.
+Return non-zero if the symbol is weak, or if it is a @code{weakref} alias or
+symbol that has not been strongly referenced.
+
+@item S_IS_WEAKREFR
+@cindex S_IS_WEAKREFR
+Return non-zero if the symbol is a @code{weakref} alias.
+
+@item S_IS_WEAKREFD
+@cindex S_IS_WEAKREFD
+Return non-zero if the symbol was aliased by a @code{weakref} alias and has not
+had any strong references.
+
+@item S_IS_VOLATILE
+@cindex S_IS_VOLATILE
+Return non-zero if the symbol may be re-defined. Such symbols get created by
+the @code{=} operator, @code{equ}, or @code{set}.
+
+@item S_IS_FORWARD_REF
+@cindex S_IS_FORWARD_REF
+Return non-zero if the symbol is a forward reference, that is its value must
+only be determined upon use.
@item S_IS_COMMON
@cindex S_IS_COMMON
@cindex S_SET_WEAK
Mark the symbol as weak.
+@item S_SET_WEAKREFR
+@cindex S_SET_WEAKREFR
+Mark the symbol as the referrer in a @code{weakref} directive. The symbol it
+aliases must have been set to the value expression before this point. If the
+alias has already been used, the symbol is marked as used too.
+
+@item S_CLEAR_WEAKREFR
+@cindex S_CLEAR_WEAKREFR
+Clear the @code{weakref} alias status of a symbol. This is implicitly called
+whenever a symbol is defined or set to a new expression.
+
+@item S_SET_WEAKREFD
+@cindex S_SET_WEAKREFD
+Mark the symbol as the referred symbol in a @code{weakref} directive.
+Implicitly marks the symbol as weak, but see below. It should only be called
+if the referenced symbol has just been added to the symbol table.
+
+@item S_SET_WEAKREFD
+@cindex S_SET_WEAKREFD
+Clear the @code{weakref} aliased status of a symbol. This is implicitly called
+whenever the symbol is looked up, as part of a direct reference or a
+definition, but not as part of a @code{weakref} directive.
+
+@item S_SET_VOLATILE
+@cindex S_SET_VOLATILE
+Indicate that the symbol may be re-defined.
+
+@item S_CLEAR_VOLATILE
+@cindex S_CLEAR_VOLATILE
+Indicate that the symbol may no longer be re-defined.
+
+@item S_SET_FORWARD_REF
+@cindex S_SET_FORWARD_REF
+Indicate that the symbol is a forward reference, that is its value must only
+be determined upon use.
+
@item S_GET_TYPE
-@item S_GET_DESC
-@item S_GET_OTHER
+@itemx S_GET_DESC
+@itemx S_GET_OTHER
@cindex S_GET_TYPE
@cindex S_GET_DESC
@cindex S_GET_OTHER
a.out).
@item S_SET_TYPE
-@item S_SET_DESC
-@item S_SET_OTHER
+@itemx S_SET_DESC
+@itemx S_SET_OTHER
@cindex S_SET_TYPE
@cindex S_SET_DESC
@cindex S_SET_OTHER
@cindex porting
Each GAS target specifies two main things: the CPU file and the object format
-file. Two main switches in the @file{configure.in} file handle this. The
+file. Two main switches in the @file{configure.ac} file handle this. The
first switches on CPU type to set the shell variable @code{cpu_type}. The
second switches on the entire target to set the shell variable @code{fmt}.
unrecognized code, presumably indicating a special code value which appears in
@code{md_longopts}. This function should return non-zero if it handled the
option and zero otherwise. There is no need to print a message about an option
-not being recognised. This will be handled by the generic code.
+not being recognized. This will be handled by the generic code.
GAS will call @code{md_show_usage} when a usage message is printed; it should
print a description of the machine specific options. @code{md_after_pase_args},
@item tc_comment_chars
@cindex tc_comment_chars
If this macro is defined, GAS will use it instead of @code{comment_chars}.
+This has the advantage that this macro does not have to refer to a constant
+array.
@item tc_symbol_chars
@cindex tc_symbol_chars
If this macro is defined, it is a pointer to a null terminated list of
characters which may appear in an operand. GAS already assumes that all
-alphanumberic characters, and @samp{$}, @samp{.}, and @samp{_} may appear in an
+alphanumeric characters, and @samp{$}, @samp{.}, and @samp{_} may appear in an
operand (see @samp{symbol_chars} in @file{app.c}). This macro may be defined
to treat additional characters as appearing in an operand. This affects the
way in which GAS removes whitespace before passing the string to
if found in a comment, such as after a character in line_comment_chars or
comment_chars.
+@item tc_line_separator_chars
+@cindex tc_line_separator_chars
+If this macro is defined, GAS will use it instead of
+@code{line_separator_chars}. This has the advantage that this macro does not
+have to refer to a constant array.
+
+
@item EXP_CHARS
@cindex EXP_CHARS
This is a null terminated @code{const char} array of characters which may be
is called, @code{input_line_pointer} will point to the start of the
expression.
+@item md_register_arithmetic
+@cindex md_register_arithmetic
+If this macro is defined and evaluates to zero then GAS will not fold
+expressions that add or subtract a constant to/from a register to give
+another register. For example GAS's default behaviour is to fold the
+expression "r8 + 1" into "r9", which is probably not the result
+intended by the programmer. The default is to allow such folding,
+since this maintains backwards compatibility with earlier releases of
+GAS.
+
@item tc_unrecognized_line
@cindex tc_unrecognized_line
If you define this macro, GAS will call it when it finds a line that it can not
@cindex md_atof
This function is called to convert an ASCII string into a floating point value
in format used by the CPU. It takes three arguments. The first is @var{type}
-which is a byte describing the type of floating point number to be created.
-Possible values are @var{'f'} or @var{'s'} for single precision, @var{'d'} or
-@var{'r'} for double precision and @var{'x'} or @var{'p'} for extended
-precision. Either lower or upper case versions of these letters can be used.
+which is a byte describing the type of floating point number to be created. It
+is one of the characters defined in the @code{FLT_CHARS} macro. Possible
+values are @var{'f'} or @var{'s'} for single precision, @var{'d'} or @var{'r'}
+for double precision and @var{'x'} or @var{'p'} for extended precision. Either
+lower or upper case versions of these letters can be used. Note: some targets
+do not support all of these types, and some targets may also support other
+types not mentioned here.
The second parameter is @var{litP} which is a pointer to a byte array where the
-converted value should be stored. The third argument is @var{sizeP}, which is
-a pointer to a integer that should be filled in with the number of
-@var{LITTLENUM}s emitted into the byte array. (@var{LITTLENUM} is defined in
-gas/bignum.h). The function should return NULL upon success or an error string
-upon failure.
+converted value should be stored. The value is converted into LITTLENUMs and
+is stored in the target's endian-ness order. (@var{LITTLENUM} is defined in
+gas/bignum.h). Single precision values occupy 2 littlenums. Double precision
+values occupy 4 littlenums and extended precision values occupy either 5 or 6
+littlenums, depending upon the target.
+
+The third argument is @var{sizeP}, which is a pointer to a integer that should
+be filled in with the number of chars emitted into the byte array.
+
+The function should return NULL upon success or an error string upon failure.
@item TC_LARGEST_EXPONENT_IS_NORMAL
@cindex TC_LARGEST_EXPONENT_IS_NORMAL (@var{precision})
@cindex TC_FINALIZE_SYMS_BEFORE_SIZE_SEG
Specifies the value to be assigned to @code{finalize_syms} before the function
@code{size_segs} is called. Since @code{size_segs} calls @code{cvt_frag_to_fill}
-which can call @code{md_convert_frag}, this constant governs whether the symbols
+which can call @code{md_convert_frag}, this constant governs whether the symbols
accessed in @code{md_convert_frag} will be fully resolved. In particular it
governs whether local symbols will have been resolved, and had their frag
information removed. Depending upon the processing performed by
@cindex TC_FORCE_RELOCATION_LOCAL
Like @code{TC_FORCE_RELOCATION}, but used only for fixup expressions against a
symbol in the current section. If undefined, fixups that are not
-@code{fx_pcrel} or @code{fx_plt} or for which @code{TC_FORCE_RELOCATION}
+@code{fx_pcrel} or for which @code{TC_FORCE_RELOCATION}
returns non-zero, will emit relocs.
@item TC_FORCE_RELOCATION_SUB_SAME (@var{fix}, @var{seg})
difference of two symbols in the same section. If this macro returns zero,
the subtrahend will be resolved and @code{fx_subsy} set to @code{NULL} for
@code{md_apply_fix}. If undefined, the default of
-@w{@code{! SEG_NORMAL (@var{seg}) || TC_FORCE_RELOCATION (@var{fix})}} will
-be used.
+@w{@code{! SEG_NORMAL (@var{seg})}} will be used.
-@item TC_FORCE_RELOCATION_SUB_ABS (@var{fix})
+@item TC_FORCE_RELOCATION_SUB_ABS (@var{fix}, @var{seg})
@cindex TC_FORCE_RELOCATION_SUB_ABS
Like @code{TC_FORCE_RELOCATION_SUB_SAME}, but used when the subtrahend is an
absolute symbol. If the macro is undefined a default of @code{0} is used.
-@item TC_FORCE_RELOCATION_SUB_LOCAL (@var{fix})
+@item TC_FORCE_RELOCATION_SUB_LOCAL (@var{fix}, @var{seg})
@cindex TC_FORCE_RELOCATION_SUB_LOCAL
Like @code{TC_FORCE_RELOCATION_SUB_ABS}, but the subtrahend is a symbol in the
same section as the fixup.
-@item TC_VALIDATE_FIX_SUB (@var{fix})
+@item TC_VALIDATE_FIX_SUB (@var{fix}, @var{seg})
@cindex TC_VALIDATE_FIX_SUB
This macro is evaluated for any fixup with a @code{fx_subsy} that
@code{fixup_segment} cannot reduce to a number. If the macro returns
@code{false} an error will be reported.
+@item TC_GLOBAL_REGISTER_SYMBOL_OK
+@cindex TC_GLOBAL_REGISTER_SYMBOL_OK
+Define this macro if global register symbols are supported. The default
+is to disallow global register symbols.
+
@item MD_APPLY_SYM_VALUE (@var{fix})
@cindex MD_APPLY_SYM_VALUE
This macro controls whether the symbol value becomes part of the value passed
@cindex tc_frob_label
If you define this macro, GAS will call it each time a label is defined.
+@item tc_new_dot_label
+@cindex tc_new_dot_label
+If you define this macro, GAS will call it each time a fake label is created
+off the special dot symbol.
+
@item md_section_align
@cindex md_section_align
GAS will call this function for each section at the end of the assembly, to
If you define this macro, GAS will call it after the relocs have been
generated.
+@item tc_cfi_reloc_for_encoding
+@cindex tc_cfi_reloc_for_encoding
+This macro is used to indicate whether a cfi encoding requires a relocation.
+It should return the required relocation type. Defining this macro implies
+that Compact EH is supported.
+
@item md_post_relax_hook
If you define this macro, GAS will call it after relaxing and sizing the
segments.
a new section's attributes when a directive has no valid flags or when the
flag is @code{w}. The default value of the macro is @code{SEC_LOAD | SEC_DATA}.
-@item DWARF2_FORMAT ()
+@item DWARF2_FORMAT (@var{sec})
@cindex DWARF2_FORMAT
If you define this, it should return one of @code{dwarf2_format_32bit},
@code{dwarf2_format_64bit}, or @code{dwarf2_format_64bit_irix} to indicate
If you don't define this, @code{dwarf2_format_32bit} will be used as
the default.
-This define only affects @code{.debug_info} and @code{.debug_line}
+This define only affects debug
sections generated by the assembler. DWARF 2 sections generated by
other tools will be unaffected by this setting.
backend. This format will be used when generating assembler specific debug
information.
+@item md_allow_local_subtract (@var{left}, @var{right}, @var{section})
+If defined, GAS will call this macro when evaluating an expression which is the
+difference of two symbols defined in the same section. It takes three
+arguments: @code{expressioS * @var{left}} which is the symbolic expression on
+the left hand side of the subtraction operation, @code{expressionS *
+@var{right}} which is the symbolic expression on the right hand side of the
+subtraction, and @code{segT @var{section}} which is the section containing the two
+symbols. The macro should return a non-zero value if the expression should be
+evaluated. Targets which implement link time relaxation which may change the
+position of the two symbols relative to each other should ensure that this
+macro returns zero in situations where this can occur.
+
+@item md_allow_eh_opt
+If defined, GAS will check this macro before performing any optimizations on
+the DWARF call frame debug information that is emitted. Targets which
+implement link time relaxation may need to define this macro and set it to zero
+if it is possible to change the size of a function's prologue.
@end table
@node Object format backend
that the symbol should not be included in the object file by defining this
macro to set its second argument to a non-zero value.
+@item obj_set_weak_hook
+@cindex obj_set_weak_hook
+If you define this macro, @code{S_SET_WEAK} will call it before modifying the
+symbol's flags.
+
+@item obj_clear_weak_hook
+@cindex obj_clear_weak_hook
+If you define this macro, @code{S_CLEAR_WEAKREFD} will call it after cleaning
+the @code{weakrefd} flag, but before modifying any other flags.
+
@item obj_frob_file
@cindex obj_frob_file
If you define this macro, GAS will call it after the symbol table has been
during this invocation.
@end deftypefun
-@deftypefun @{@} void as_perror (const char *@var{gripe}, const char *@var{filename})
-Displays a BFD or system error, then clears the error status.
-@end deftypefun
-
@deftypefun @{@} void as_tsktsk (const char *@var{format}, ...)
@deftypefunx @{@} void as_warn (const char *@var{format}, ...)
@deftypefunx @{@} void as_bad (const char *@var{format}, ...)
Destroy a hash table.
@end deftypefun
-@deftypefun @{@} PTR hash_delete (struct hash_control *, const char *)
-Deletes entry from the hash table, returns the value it had.
+@deftypefun @{@} void *hash_delete (struct hash_control *, const char *, int)
+Deletes entry from the hash table, returns the value it had. If the last
+arg is non-zero, free memory allocated for this entry and all entries
+allocated more recently than this entry.
@end deftypefun
-@deftypefun @{@} PTR hash_replace (struct hash_control *, const char *, PTR)
+@deftypefun @{@} void *hash_replace (struct hash_control *, const char *, void *)
Updates the value for an entry already in the table, returning the old value.
If no entry was found, just returns NULL.
@end deftypefun
-@deftypefun @{@} @{const char *@} hash_insert (struct hash_control *, const char *, PTR)
+@deftypefun @{@} @{const char *@} hash_insert (struct hash_control *, const char *, void *)
Inserting a value already in the table is an error.
Returns an error message or NULL.
@end deftypefun
-@deftypefun @{@} @{const char *@} hash_jam (struct hash_control *, const char *, PTR)
+@deftypefun @{@} @{const char *@} hash_jam (struct hash_control *, const char *, void *)
Inserts if the value isn't already present, updates it if it is.
@end deftypefun
projects / deliverable / binutils-gdb.git / blobdiff