Object files contain COFF relocations, which specify how the section data should be modified when placed in the image file and subsequently loaded into memory.
Image files do not contain COFF relocations, because all symbols referenced have already been assigned addresses in a flat address space. An image contains relocation information in the form of base relocations in the .reloc section (unless the image has the IMAGE_FILE_RELOCS_STRIPPED attribute). See Section 6.5 for more information.
For each section in an object file, there is an array of fixed-length records that are the section’s COFF relocations. The position and length of the array are specified in the section header. Each element of the array has the following format:
| Offset | Size | Field | Description |
| 0 | 4 | VirtualAddress | Address of the item to which relocation is applied: this is the offset from the beginning of the section, plus the value of the section’s RVA/Offset field (see Section 4, “Section Table.”). For example, if the first byte of the section has an address of 0x10, the third byte has an address of 0x12. |
| 4 | 4 | SymbolTableIndex | A zero-based index into the symbol table. This symbol gives the address to be used for the relocation. If the specified symbol has section storage class, then the symbol’s address is the address with the first section of the same name. |
| 8 | 2 | Type | A value indicating what kind of relocation should be performed. Valid relocation types depend on machine type. See Section 5.2.1, “Type Indicators.” |
If the symbol referred to (by the SymbolTableIndex field) has storage class IMAGE_SYM_CLASS_SECTION, the symbol’s address is the beginning of the section. The section is usually in the same file, except when the object file is part of an archive (library). In that case, the section may be found in any other object file in the archive that has the same archive-member name as the current object file. (The relationship with the archive-member name is used in the linking of import tables, i.e. the .idata section.)
The Type field of the relocation record indicates what kind of relocation should be performed. Different relocation types are defined for each type of machine.
The following relocation type indicators are defined for Intel386 and compatible processors:
| Constant | Value | Description |
| IMAGE_REL_I386_ABSOLUTE | 0x0000 | This relocation is ignored. |
| IMAGE_REL_I386_DIR16 | 0x0001 | Not supported. |
| IMAGE_REL_I386_REL16 | 0x0002 | Not supported. |
| IMAGE_REL_I386_DIR32 | 0x0006 | The target’s 32-bit virtual address. |
| IMAGE_REL_I386_DIR32NB | 0x0007 | The target’s 32-bit relative virtual address. |
| IMAGE_REL_I386_SEG12 | 0x0009 | Not supported. |
| IMAGE_REL_I386_SECTION | 0x000A | The 16-bit-section index of the section containing the target. This is used to support debugging information. |
| IMAGE_REL_I386_SECREL | 0x000B | The 32-bit offset of the target from the beginning of its section. This is used to support debugging information as well as static thread local storage. |
| IMAGE_REL_I386_REL32 | 0x0014 | The 32-bit relative displacement to the target. This supports the x86 relative branch and call instructions. |
The following relocation type indicators are defined for MIPS processors:
| Constant | Value | Description |
| IMAGE_REL_MIPS_ABSOLUTE | 0x0000 | This relocation is ignored. |
| IMAGE_REL_MIPS_REFHALF | 0x0001 | The high 16 bits of the target’s 32-bit virtual address. |
| IMAGE_REL_MIPS_REFWORD | 0x0002 | The target’s 32-bit virtual address. |
| IMAGE_REL_MIPS_JMPADDR | 0x0003 | The low 26 bits of the target’s virtual address. This supports the MIPS J and JAL instructions. |
| IMAGE_REL_MIPS_REFHI | 0x0004 | The high 16 bits of the target’s 32-bit virtual address. Used for the first instruction in a two-instruction sequence that loads a full address. This relocation must be immediately followed by a PAIR relocations whose SymbolTableIndex contains a signed 16-bit displacement which is added to the upper 16 bits taken from the location being relocated. |
| IMAGE_REL_MIPS_REFLO | 0x0005 | The low 16 bits of the target’s virtual address. |
| IMAGE_REL_MIPS_GPREL | 0x0006 | 16-bit signed displacement of the target relative to the Global Pointer (GP) register. |
| IMAGE_REL_MIPS_LITERAL | 0x0007 | Same as IMAGE_REL_MIPS_GPREL. |
| IMAGE_REL_MIPS_SECTION | 0x000A | The 16-bit section index of the section containing the target. This is used to support debugging information. |
| IMAGE_REL_MIPS_SECREL | 0x000B | The 32-bit offset of the target from the beginning of its section. This is used to support debugging information as well as static thread local storage. |
| IMAGE_REL_MIPS_SECRELLO | 0x000C | The low 16 bits of the 32-bit offset of the target from the beginning of its section. |
| IMAGE_REL_MIPS_SECRELHI | 0x000D | The high 16 bits of the 32-bit offset of the target from the beginning of its section. A PAIR relocation must immediately follow this on. The SymbolTableIndex of the PAIR relocation contains a signed 16-bit displacement, which is added to the upper 16 bits taken from the location being relocated. |
| IMAGE_REL_MIPS_JMPADDR16 | 0x0010 | The low 26 bits of the target’s virtual address. This supports the MIPS16 JAL instruction. |
| IMAGE_REL_MIPS_REFWORDNB | 0x0022 | The target’s 32-bit relative virtual address. |
| IMAGE_REL_MIPS_PAIR | 0x0025 | This relocation is only valid when it immediately follows a REFHI or SECRELHI relocation. Its SymbolTableIndex contains a displacement and not an index into the symbol table. |
The following relocation Type indicators are defined for Alpha processors:
| Constant | Value | Description |
| IMAGE_REL_ALPHA_ABSOLUTE | 0x0000 | This relocation is ignored. |
| IMAGE_REL_ALPHA_REFLONG | 0x0001 | The target’s 32-bit virtual address. This fixup is illegal in a PE32+ image unless the image has been sandboxed by clearing the IMAGE_FILE_LARGE_ADDRESS_AWARE bit in the File Header. |
| IMAGE_REL_ALPHA_REFQUAD | 0x0002 | The target’s 64-bit virtual address. |
| IMAGE_REL_ALPHA_GPREL32 | 0x0003 | 32-bit signed displacement of the target relative to the Global Pointer (GP) register. |
| IMAGE_REL_ALPHA_LITERAL | 0x0004 | 16-bit signed displacement of the target relative to the Global Pointer (GP) register. |
| IMAGE_REL_ALPHA_LITUSE | 0x0005 | Reserved for future use. |
| IMAGE_REL_ALPHA_GPDISP | 0x0006 | Reserved for future use. |
| IMAGE_REL_ALPHA_BRADDR | 0x0007 | The 21-bit relative displacement to the target. This supports the Alpha relative branch instructions. |
| IMAGE_REL_ALPHA_HINT | 0x0008 | 14-bit hints to the processor for the target of an Alpha jump instruction. |
| IMAGE_REL_ALPHA_INLINE_REFLONG | 0x0009 | The target’s 32-bit virtual address split into high and low 16-bit parts. Either an ABSOLUTE or MATCH relocation must immediately follow this relocation. The high 16 bits of the target address are stored in the location identified by the INLINE_REFLONG relocation. The low 16 bits are stored four bytes later if the following relocation is of type ABSOLUTE or at a signed displacement given in the SymbolTableIndex if the following relocation is of type MATCH. |
| IMAGE_REL_ALPHA_REFHI | 0x000A | The high 16 bits of the target’s 32-bit virtual address. Used for the first instruction in a two-instruction sequence that loads a full address. This relocation must be immediately followed by a PAIR relocations whose SymbolTableIndex contains a signed 16-bit displacement which is added to the upper 16 bits taken from the location being relocated. |
| IMAGE_REL_ALPHA_REFLO | 0x000B | The low 16 bits of the target’s virtual address. |
| IMAGE_REL_ALPHA_PAIR | 0x000C | This relocation is only valid when it immediately follows a REFHI , REFQ3, REFQ2, or SECRELHI relocation. Its SymbolTableIndex contains a displacement and not an index into the symbol table. |
| IMAGE_REL_ALPHA_MATCH | 0x000D | This relocation is only valid when it immediately follows INLINE_REFLONG relocation. Its SymbolTableIndex contains the displacement in bytes of the location for the matching low address and not an index into the symbol table. |
| IMAGE_REL_ALPHA_SECTION | 0x000E | The 16-bit section index of the section containing the target. This is used to support debugging information. |
| IMAGE_REL_ALPHA_SECREL | 0x000F | The 32-bit offset of the target from the beginning of its section. This is used to support debugging information as well as static thread local storage. |
| IMAGE_REL_ALPHA_REFLONGNB | 0x0010 | The target’s 32-bit relative virtual address. |
| IMAGE_REL_ALPHA_SECRELLO | 0x0011 | The low 16 bits of the 32-bit offset of the target from the beginning of its section. |
| IMAGE_REL_ALPHA_SECRELHI | 0x0012 | The high 16 bits of the 32-bit offset of the target from the beginning of its section. A PAIR relocation must immediately follow this on. The SymbolTableIndex of the PAIR relocation contains a signed 16-bit displacement which is added to the upper 16 bits taken from the location being relocated. |
| IMAGE_REL_ALPHA_REFQ3 | 0x0013 | The low 16 bits of the high 32 bits of the target’s 64-bit virtual address. This relocation must be immediately followed by a PAIR relocations whose SymbolTableIndex contains a signed 32-bit displacement which is added to the 16 bits taken from the location being relocated. The 16 bits in the relocated location are shifted left by 32 before this addition. |
| IMAGE_REL_ALPHA_REFQ2 | 0x0014 | The high 16 bits of the low 32 bits of the target’s 64-bit virtual address. This relocation must be immediately followed by a PAIR relocations whose SymbolTableIndex contains a signed 16-bit displacement which is added to the upper 16 bits taken from the location being relocated. |
| IMAGE_REL_ALPHA_REFQ1 | 0x0015 | The low 16 bits of the target’s 64-bit virtual address. |
| IMAGE_REL_ALPHA_GPRELLO | 0x0016 | The low 16 bits of the 32-bit signed displacement of the target relative to the Global Pointer (GP) register. |
| IMAGE_REL_ALPHA_GPRELHI | 0x0017 | The high 16 bits of the 32-bit signed displacement of the target relative to the Global Pointer (GP) register. |
The following relocation Type indicators are defined for PowerPC processors:
| Constant | Value | Description |
| IMAGE_REL_PPC_ABSOLUTE | 0x0000 | This relocation is ignored. |
| IMAGE_REL_PPC_ADDR64 | 0x0001 | The target’s 64-bit virtual address. |
| IMAGE_REL_PPC_ADDR32 | 0x0002 | The target’s 32-bit virtual address. |
| IMAGE_REL_PPC_ADDR24 | 0x0003 | The low 24 bits of the target’s virtual address. This is only valid when the target symbol is absolute and can be sign extended to its original value. |
| IMAGE_REL_PPC_ADDR16 | 0x0004 | The low 16 bits of the target’s virtual address. |
| IMAGE_REL_PPC_ADDR14 | 0x0005 | The low 14 bits of the target’s virtual address. This is only valid when the target symbol is absolute and can be sign extended to its original value. |
| IMAGE_REL_PPC_REL24 | 0x0006 | A 24-bit PC-relative offset to the symbol’s location. |
| IMAGE_REL_PPC_REL14 | 0x0007 | A 14-bit PC-relative offset to the symbol’s location. |
| IMAGE_REL_PPC_ADDR32NB | 0x000A | The target’s 32-bit relative virtual address. |
| IMAGE_REL_PPC_SECREL | 0x000B | The 32-bit offset of the target from the beginning of its section. This is used to support debugging information as well as static thread local storage. |
| IMAGE_REL_PPC_SECTION | 0x000C | The 16-bit section index of the section containing the target. This is used to support debugging information. |
| IMAGE_REL_PPC_SECREL16 | 0x000F | The 16-bit offset of the target from the beginning of its section. This is used to support debugging information as well as static thread local storage. |
| IMAGE_REL_PPC_REFHI | 0x0010 | The high 16 bits of the target’s 32-bit virtual address. Used for the first instruction in a two-instruction sequence that loads a full address. This relocation must be immediately followed by a PAIR relocations whose SymbolTableIndex contains a signed 16-bit displacement which is added to the upper 16 bits taken from the location being relocated. |
| IMAGE_REL_PPC_REFLO | 0x0011 | The low 16 bits of the target’s virtual address. |
| IMAGE_REL_PPC_PAIR | 0x0012 | This relocation is only valid when it immediately follows a REFHI or SECRELHI relocation. Its SymbolTableIndex contains a displacement and not an index into the symbol table. |
| IMAGE_REL_PPC_SECRELLO | 0x0013 | The low 16 bits of the 32-bit offset of the target from the beginning of its section. |
| IMAGE_REL_PPC_SECRELHI | 0x0014 | The high 16 bits of the 32-bit offset of the target from the beginning of its section. A PAIR relocation must immediately follow this on. The SymbolTableIndex of the PAIR relocation contains a signed 16-bit displacement which is added to the upper 16 bits taken from the location being relocated. |
| IMAGE_REL_PPC_GPREL | 0x0015 | 16-bit signed displacement of the target relative to the Global Pointer (GP) register. |
The following relocation type indicators are defined for SH3 and SH4 processors:
| Constant | Value | Description |
| IMAGE_REL_SH3_ABSOLUTE | 0x0000 | This relocation is ignored. |
| IMAGE_REL_SH3_DIRECT16 | 0x0001 | Reference to the 16-bit location that contains the virtual address of the target symbol. |
| IMAGE_REL_SH3_DIRECT32 | 0x0002 | The target’s 32-bit virtual address. |
| IMAGE_REL_SH3_DIRECT8 | 0x0003 | Reference to the 8-bit location that contains the virtual address of the target symbol. |
| IMAGE_REL_SH3_DIRECT8_WORD | 0x0004 | Reference to the 8-bit instruction that contains the effective 16-bit virtual address of the target symbol. |
| IMAGE_REL_SH3_DIRECT8_LONG | 0x0005 | Reference to the 8-bit instruction that contains the effective 32-bit virtual address of the target symbol. |
| IMAGE_REL_SH3_DIRECT4 | 0x0006 | Reference to the 8-bit location whose low 4 bits contain the virtual address of the target symbol. |
| IMAGE_REL_SH3_DIRECT4_WORD | 0x0007 | Reference to the 8-bit instruction whose low 4 bits contain the effective 16-bit virtual address of the target symbol. |
| IMAGE_REL_SH3_DIRECT4_LONG | 0x0008 | Reference to the 8-bit instruction whose low 4 bits contain the effective 32-bit virtual address of the target symbol. |
| IMAGE_REL_SH3_PCREL8_WORD | 0x0009 | Reference to the 8-bit instruction which contains the effective 16-bit relative offset of the target symbol. |
| IMAGE_REL_SH3_PCREL8_LONG | 0x000A | Reference to the 8-bit instruction which contains the effective 32-bit relative offset of the target symbol. |
| IMAGE_REL_SH3_PCREL12_WORD | 0x000B | Reference to the 16-bit instruction whose low 12 bits contain the effective 16-bit relative offset of the target symbol. |
| IMAGE_REL_SH3_STARTOF_SECTION | 0x000C | Reference to a 32-bit location that is the virtual address of the symbol’s section. |
| IMAGE_REL_SH3_SIZEOF_SECTION | 0x000D | Reference to the 32-bit location that is the size of the symbol’s section. |
| IMAGE_REL_SH3_SECTION | 0x000E | The 16-bit section index of the section containing the target. This is used to support debugging information. |
| IMAGE_REL_SH3_SECREL | 0x000F | The 32-bit offset of the target from the beginning of its section. This is used to support debugging information as well as static thread local storage. |
| IMAGE_REL_SH3_DIRECT32_NB | 0x0010 | The target’s 32-bit relative virtual address. |
The following relocation Type indicators are defined for ARM processors:
| Constant | Value | Description |
| IMAGE_REL_ARM_ABSOLUTE | 0x0000 | This relocation is ignored. |
| IMAGE_REL_ARM_ADDR32 | 0x0001 | The target’s 32-bit virtual address. |
| IMAGE_REL_ARM_ADDR32NB | 0x0002 | The target’s 32-bit relative virtual address. |
| IMAGE_REL_ARM_BRANCH24 | 0x0003 | The 24-bit relative displacement to the target. |
| IMAGE_REL_ARM_BRANCH11 | 0x0004 | Reference to a subroutine call, consisting of two 16-bit instructions with 11-bit offsets. |
| IMAGE_REL_ARM_SECTION | 0x000E | The 16-bit section index of the section containing the target. This is used to support debugging information. |
| IMAGE_REL_ARM_SECREL | 0x000F | The 32-bit offset of the target from the beginning of its section. This is used to support debugging information as well as static thread local storage. |