Steering file commands

where:

You cannot import a symbol that has been defined in the current shared object or executable. Only one wildcard character (either * or ?) is permitted in IMPORT.

The undefined symbol is included in the dynamic symbol table (as replacement_pattern if given, otherwise as pattern), if a dynamic symbol table is present.

where:

You cannot export a symbol to a name that already exists. Only one wildcard character (either * or ?) is permitted in EXPORT.

The defined global symbol is included in the dynamic symbol table (as replacement_pattern if given, otherwise as pattern), if a dynamic symbol table is present.

where:

You cannot rename a symbol to a symbol name that already exists, even if the target symbol name is being renamed itself. Only one wildcard character (either * or ?) is permitted in RENAME. For example, given an image containing the symbols func1, func2, and func3:

EXPORT func1 AS func2    ;invalid, func2 exists
RENAME func3 AS b2
EXPORT func1 AS func3    ;invalid, func3 exists, even though it is renamed to b2

The linker processes the steering file before doing any replacements. You cannot, therefore, use RENAME A AS B on line 1 and then RENAME B AS A on line 2.

where:

RESOLVE is an extension of the existing armlink ‑‑unresolved command-line option. The difference is that ‑‑unresolved enables all undefined references to match one single definition, whereas RESOLVE enables more specific matching of references to symbols.

The undefined references are removed from the output symbol table.

RESOLVE works when performing partial-linking and when linking normally.

For example, you might have two files file1.c and file2.c, as shown in Example 4.4. Create an ed.txt file containing the line RESOLVE MP3* AS MyMP3*, and issue the following command:

armlink file1.o file2.o ‑‑edit ed.txt ‑‑unresolved foobar

This command has the following effects:

file1.c

extern int foo;
extern void MP3_Init(void);
extern void MP3_Play(void);

int main(void)
{
  int x = foo + 1;
  MP3_Init();
  MP3_Play();
  return x;
}


file2.c:

int foobar;
void MyMP3_Init()
{
}
void MyMP3_Play()
{
}

where:

The linker inserts a DT_NEEDED tag with the value of pattern into the dynamic array. This tells the dynamic loader that the file it is currently loading requires pattern to be loaded.

where:

HIDE and SHOW can be used to make certain global symbols anonymous in an output image or partially linked object. Hiding symbols in an object file or library can be useful as a means of protecting intellectual property, as shown in Example 4.5. This example produces a partially linked object with all global symbols hidden, except those beginning with os_.

steer.txt

HIDE *            ; Hides all global symbols
SHOW os_*         ; Shows all symbols beginning with ’os_’

Link this example with the command:

armlink ‑‑partial input_object.o ‑‑edit steer.txt ‑o partial_object.o

This example can be linked with other objects, provided they do not contain references to the hidden symbols. When symbols are hidden in the output object, SHOW commands in subsequent link steps have no effect on them. The hidden references are removed from the output symbol table.

where:

The usage of SHOW is closely related to that of HIDE. See HIDE for further information.