Linker::Segment Class Reference

A class representing a sequence of sections that must be written to the output file as a group. More...

#include <segment.h>

Inheritance diagram for Linker::Segment:

Public Member Functions
	Segment (std::string name, offset_t base_address=0)
bool	IsMissing ()
	Segment that contains neither non zero filled, nor zero filled, nor optional extra data.
void	Fill ()
	Fills zero filled sections with zero data, making them non-zero filled in the sense that they have to be written to disk.
void	RealignEnd (offset_t align)
	Aligns end of segment by increasing size of last section.
void	Append (std::shared_ptr< Section > section)
	Appends section to segment.
offset_t	WriteFile (std::ostream &out, offset_t size, offset_t offset=0) const
	Writes data of non-zero filled sections.
offset_t	WriteFile (std::ostream &out) const
	Writes data of non-zero filled sections.
offset_t	WriteFile (Writer &wr, offset_t count, offset_t offset=0) const override
	Writes data of non-zero filled sections.
offset_t	WriteFile (Writer &wr) const override
	Writes data of non-zero filled sections.
size_t	ReadData (size_t bytes, offset_t offset, void *buffer) const override
	Attempts to fill a buffer with data.
offset_t	TotalSize ()
	Retrieves total size of segment.
offset_t	ImageSize () const override
	Retrieves size of all data in segment, as present in the binary image.
offset_t	GetStartAddress ()
	Returns starting address (base_address)
offset_t	GetEndAddress ()
	Returns end address (GetStartAddress() + TotalSize())
void	SetEndAddress (offset_t address)
	Increases final section to end on specified address.
void	AlignEndAddress (offset_t align)
	Aligns the end of the segment.
void	SetStartAddress (offset_t address)
	Forcibly resets starting address of segment.
Public Member Functions inherited from Linker::ActualImage
std::shared_ptr< const ActualImage >	AsImage () const override
	Retrieves a randomly accessible image.
uint64_t	ReadUnsigned (size_t bytes, offset_t offset, EndianType endiantype) const
	Reads an unsigned number at a specific offset.
uint64_t	ReadUnsigned (size_t bytes, offset_t offset) const
	Reads an unsigned number at a specific offset with the default endianness.
int64_t	ReadSigned (size_t bytes, offset_t offset, EndianType endiantype) const
	Reads a signed number at a specific offset.
int64_t	ReadSigned (size_t bytes, offset_t offset) const
	Reads a signed number at a specific offset with the default endianness.
int	GetByte (offset_t offset) const
	Retrieve byte at a certain offset (optional, might not be defined)
Public Member Functions inherited from Linker::Image
std::shared_ptr< ActualImage >	AsImage ()
	Retrieves a randomly accessible image.

Public Attributes
std::string	name
	The name of the segment.
std::vector< std::shared_ptr< Section > >	sections
	Sequence of sections belonging to the segment.
offset_t	base_address
	Address where segment starts.
offset_t	align = 1
	Alignment requirements of segment.
offset_t	data_size = 0
	Cached value of the non-filled data for the entire segment.
offset_t	zero_fill = 0
	Extra zero filled space following filled data.
offset_t	optional_extra = 0
	Optional extra space after zero filled data.

Protected Member Functions
void	ShiftAddress (int64_t amount)
std::shared_ptr< Segment >	shared_from_this ()

Detailed Description

A class representing a sequence of sections that must be written to the output file as a group.

A segment represents a collection of sections that appear within the same addressing space. It also makes it easier to write several sections into the output file consecutively.

Only sections that appear consecutively in memory (or with known displacements at linking time) may be stored in the same segment.

Member Function Documentation

Append()

void Segment::Append

(

std::shared_ptr< Section >

section

)

Appends section to segment.

This action might require aligning end of last section, possibly zero filling it, and setting the base address and bias of the new section.

ImageSize()

offset_t Segment::ImageSize ( ) const

overridevirtual

Retrieves size of all data in segment, as present in the binary image.

This function should always return the same value as data_size. This is checked by an assert value.

Implements Linker::Image.

ReadData()

size_t Segment::ReadData ( size_t bytes, offset_t offset, void * buffer ) const

overridevirtual

Attempts to fill a buffer with data.

Parameters

bytes	The (maximum) number of bytes to place in buffer
offset	The offset in the image to start reading the data
buffer	A byte buffer

Returns

Actual number of bytes copied into buffer

Implements Linker::ActualImage.

SetEndAddress()

void Segment::SetEndAddress

(

offset_t

address

)

Increases final section to end on specified address.

Note that decreasing a segment is not possible

WriteFile() [1/2]

offset_t Segment::WriteFile ( Writer & wr ) const

overridevirtual

Writes data of non-zero filled sections.

Reimplemented from Linker::Image.

WriteFile() [2/2]

offset_t Segment::WriteFile ( Writer & wr, offset_t count, offset_t offset = 0 ) const

overridevirtual

Writes data of non-zero filled sections.

Implements Linker::Image.

Member Data Documentation

data_size

offset_t Linker::Segment::data_size = 0

Cached value of the non-filled data for the entire segment.

This should be equal to the sum of all sizes of sections are not zero filled. Note that a non zero filled section may not follow a zero filled one.

zero_fill

offset_t Linker::Segment::zero_fill = 0

Extra zero filled space following filled data.

This should be equal to the sum of all sizes of sections are zero filled. Note that a non zero filled section may not follow a zero filled one.

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The documentation for this class was generated from the following files:

• src/linker/segment.h
• src/linker/segment.cc