Chapter 8. Assembler Directives

61

@progbits

section contains data

@nobits

section does not contain data (i.e., section only occupies space)

@note

section contains data which is used by things other than the program

@init_array

section contains an array of pointers to init functions

@fini_array

section contains an array of pointers to finish functions

@preinit_array

section contains an array of pointers to pre init functions

Many targets only support the first three section types.

Note on targets where the

@

character is the start of a comment (eg ARM) then another character is

used instead. For example the ARM port uses the

%

character.

If

flags

contains the

M

symbol then the

type

argument must be specified as well as an extra argument

entsize

  like this:

.section name , "flags"M, @type, entsize

Sections with the

M

flag but not

S

flag must contain fixed size constants, each

entsize

octets long.

Sections with both

M

and

S

must contain zero terminated strings where each character is

entsize

bytes long. The linker may remove duplicates within sections with the same name, same entity size

and same flags.

entsize

must be an absolute expression.

If

flags

contains the

G

symbol then the

type

argument must be present along with an additional

field like this:

.section name , "flags"G, @type, GroupName[, linkage]

The

GroupName

field specifies the name of the section group to which this particular section belongs.

The optional linkage field can contain:

comdat

indicates that only one copy of this section should be retained

.gnu.linkonce

an alias for comdat

Note   if both the

M

and

G

flags are present then the fields for the Merge flag should come first, like

this:

.section name , "flags"MG, @type, entsize, GroupName[, linkage]