代码链接后空间分布 Code RO RW ZI

5.3 Example of using the --info linker option

This is an example of the output generated by the --info option

To display the component sizes when linking enter:

armlink --info sizes …

Here, sizes gives a list of the Code and data sizes for each input object and library member in the image. Using this option implies --info sizes,totals.

The following example shows the output in tabular format with the totals separated out for easy reading:

Code (inc. data)   RO Data   RW Data    ZI Data      Debug
3712        1580        19        44      10200       7436   Object Totals
0              0        16         0          0          0   (incl. Generated)
0              0         3         0          0          0   (incl. Padding)
21376        648       805         4        300      10216   Library Totals 
0              0         6         0          0          0   (incl. Padding)
===============================================================================
Code (inc. data)   RO Data    RW Data    ZI Data      Debug
25088       2228       824         48      10500      17652   Grand Totals
25088       2228       824         48      10500      17652   ELF Image Totals
25088       2228       824         48          0          0   ROM Totals
===============================================================================
Total RO  Size (Code + RO Data)             25912 (  25.30kB)
Total RW  Size (RW Data + ZI Data)          10548 (  10.30kB)
Total ROM Size (Code + RO Data + RW Data)   25960 (  25.35kB)

In this example:

Code (inc. data)

Shows how many bytes are occupied by code. In this image, there are 3712 bytes of code. This includes 1580 bytes of inline data (inc. data), for example, literal pools, and short strings.

RO Data

Shows how many bytes are occupied by RO data. This is in addition to the inline data included in the Code (inc. data) column.

RW Data

Shows how many bytes are occupied by RW data.

ZI Data

Shows how many bytes are occupied by ZI data.

Debug

Shows how many bytes are occupied by debug data, for example, debug input sections and the symbol and string table.

Object Totals

Shows how many bytes are occupied by objects linked together to generate the image.

(incl. Generated)

armlink might generate image contents, for example, interworking veneers, and input sections such as region tables. If the Object Totals row includes this type of data, it is shown in this row.

In the example, there are 19 bytes of RO data in total, of which 16 bytes is linker-generated RO data.

Library Totals

Shows how many bytes are occupied by library members that have been extracted and added to the image as individual objects.

(incl. Padding)

armlink inserts padding, if required, to force section alignment. If the Object Totals row includes this type of data, it is shown in the associated (incl. Padding) row. Similarly, if the Library Totals row includes this type of data, it is shown in its associated row.

In the example, there are 19 bytes of RO data in the object total, of which 3 bytes is linker-generated padding, and 805 bytes of RO data in the library total, with 6 bytes of padding.

Grand Totals

Shows the true size of the image. In the example, there are 10200 bytes of ZI data (in Object Totals) and 300 of ZI data (in Library Totals) giving a total of 10500 bytes.

ELF Image Totals

If you are using RW data compression (the default) to optimize ROM size, the size of the final image changes and this is reflected in the output from --info. Compare the number of bytes under Grand Totals and ELF Image Totalsto see the effect of compression.

In the example, RW data compression is not enabled. If data is compressed, the RW value changes.

ROM Totals

Shows the minimum size of ROM required to contain the image. This does not include ZI data and debug information which is not stored in the ROM.

Related reference

5.1 Options for getting information about linker-generated files

9.53 --info=topic[,topic,…]

 

 

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