Linker and Libraries Guide

x64: Relocation Types

The relocations that are listed in the following table are defined for x64.

Table 7–16 x64: ELF Relocation Types


Name	Value	Field	Calculation
`R_AMD64_NONE`	`0`	None	None
`R_AMD64_64`	`1`	`word64`	`S + A`
`R_AMD64_PC32`	`2`	`word32`	`S + A - P`
`R_AMD64_GOT32`	`3`	`word32`	`G + A`
`R_AMD64_PLT32`	`4`	`word32`	`L + A - P`
`R_AMD64_COPY`	`5`	None	Refer to the explanation following this table.
`R_AMD64_GLOB_DAT`	`6`	`word64`	`S`
`R_AMD64_JUMP_SLOT`	`7`	`word64`	`S`
`R_AMD64_RELATIVE`	`8`	`word64`	`B + A`
`R_AMD64_GOTPCREL`	`9`	`word32`	`G + GOT + A - P`
`R_AMD64_32`	`10`	`word32`	`S + A`
`R_AMD64_32S`	`11`	`word32`	`S + A`
`R_AMD64_16`	`12`	`word16`	`S + A`
`R_AMD64_PC16`	`13`	`word16`	`S + A - P`
`R_AMD64_8`	`14`	`word8`	`S + A`
`R_AMD64_PC8`	`15`	`word8`	`S + A - P`
`R_AMD64_PC64`	`24`	`word64`	`S + A - P`
`R_AMD64_GOTOFF64`	`25`	`word64`	`S + A - GOT`
`R_AMD64_GOTPC32`	`26`	`word32`	`GOT + A + P`

Note –

Additional relocations are available for thread-local storage references. These relocations are covered in Chapter 8, Thread-Local Storage.

The special semantics for most of these relocation types are identical to those used for x86. Some relocation types have semantics beyond simple calculation.

R_AMD64_GOTPCREL

This relocations has different semantics from the R_AMD64_GOT32 or equivalent R_386_GOTPC relocation. The x64 architecture provides an addressing mode that is relative to the instruction pointer. Therefore, an address can be loaded from the GOT using a single instruction.

The calculation for the R_AMD64_GOTPCREL relocation provides the difference between the location in the GOT where the symbol's address is given, and the location where the relocation is applied.

R_AMD64_32

The computed value is truncated to 32–bits. The link-editor verifies that the generated value for the relocation zero-extends to the original 64–bit value.

R_AMD64_32S

The computed value is truncated to 32–bits. The link-editor verifies that the generated value for the relocation sign-extends to the original 64–bit value.

R_AMD64_8, R_AMD64_16, R_AMD64_PC16, and R_AMD64_PC8

These relocations are not conformant to the x64 ABI, but are added here for documentation purposes. The R_AMD64_8 relocation truncates the computed value to 8-bits. The R_AMD64_16 relocation truncates the computed value to 16-bits.