15.57 RELOC

The RELOC directive explicitly encodes an ELF relocation in an object file.

Syntax

RELOC n, symbol

RELOC n

where:

n

must be an integer in the range 0 to 255 or one of the relocation names defined in the Application Binary Interface for the ARM Architecture.

symbol

can be any PC-relative label.

Usage

Use RELOC n, symbol to create a relocation with respect to the address labeled by symbol.

If used immediately after an ARM or Thumb instruction, RELOC results in a relocation at that instruction. If used immediately after a DCB, DCW, or DCD, or any other data generating directive, RELOC results in a relocation at the start of the data. Any addend to be applied must be encoded in the instruction or in the data.

If the assembler has already emitted a relocation at that place, the relocation is updated with the details in the RELOC directive, for example:

DCD     sym2 ; R_ARM_ABS32 to sym32
RELOC   55   ; ... makes it R_ARM_ABS32_NOI

RELOC is faulted in all other cases, for example, after any non-data generating directive, LTORG, ALIGN, or as the first thing in an AREA.

Use RELOC n to create a relocation with respect to the anonymous symbol, that is, symbol 0 of the symbol table. If you use RELOC n without a preceding assembler generated relocation, the relocation is with respect to the anonymous symbol.

Examples

IMPORT  impsym
LDR     r0,[pc,#-8]
RELOC   4, impsym
DCD     0
RELOC   2, sym
DCD     0,1,2,3,4       ; the final word is relocated
RELOC   38,sym2         ; R_ARM_TARGET1
DCD     impsym
RELOC   R_ARM_TARGET1   ; relocation code 38
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