An object file is divided into sections containing different types of data. In the most common case, there are three sections: the text section, which holds instructions and read-only data; the data section, which holds initialized writable data; and the bss section, which holds uninitialized data. Some systems have other kinds of sections.
The compiler must tell the assembler when to switch sections. These macros control what commands to output to tell the assembler this. You can also define additional sections.
TEXT_SECTION_ASM_OP
".text"
is right.
DATA_SECTION_ASM_OP
".data"
is right.
SHARED_SECTION_ASM_OP
DATA_SECTION_ASM_OP
will be used.
INIT_SECTION_ASM_OP
EXTRA_SECTIONS
in_text
and in_data
. You need not define this macro
on a system with no other sections (that GCC needs to use).
EXTRA_SECTION_FUNCTIONS
varasm.c
'. These
functions should do jobs analogous to those of text_section
and
data_section
, for your additional sections. Do not define this
macro if you do not define EXTRA_SECTIONS
.
READONLY_DATA_SECTION
data_section
or a function defined in EXTRA_SECTIONS
) that
switches to the section to be used for read-only items.
If these items should be placed in the text section, this macro should not be defined.
SELECT_SECTION (exp, reloc)
VAR_DECL
node or a constant of some sort. reloc
indicates whether the initial value of exp requires link-time
relocations. Select the section by calling text_section
or one
of the alternatives for other sections.
Do not define this macro if you put all read-only variables and constants in the read-only data section (usually the text section).
SELECT_RTX_SECTION (mode, rtx)
const_int
rtx. Select the section by
calling text_section
or one of the alternatives for other
sections.
Do not define this macro if you put all constants in the read-only data section.
JUMP_TABLES_IN_TEXT_SECTION
tablejump
insns) should be
output in the text section, along with the assembler instructions.
Otherwise, the readonly data section is used.
This macro is irrelevant if there is no separate readonly data section.
ENCODE_SECTION_INFO (decl)
The macro definition, if any, is executed immediately after the rtl for
decl has been created and stored in DECL_RTL (decl)
.
The value of the rtl will be a mem
whose address is a
symbol_ref
.
The usual thing for this macro to do is to record a flag in the
symbol_ref
(such as SYMBOL_REF_FLAG
) or to store a
modified name string in the symbol_ref
(if one bit is not enough
information).
STRIP_NAME_ENCODING (var, sym_name)
ENCODE_SECTION_INFO
alters the symbol's name string.