How to add some padding for a block in IAR linker configuration file - sections

Question

I am working on an IAR project. In its linker configuration file, a block is defined as the following
define block MY_BLOCK with alignment = 32 { section myblock };
place in CODE_RAM { block MY_BLOCK };
This created a MY_BLOCK memory object with 32 byte alignment， which is linked into physical memory CODE_RAM.
What I want to achieve is, leaving some extra padding area (say 64 bytes) in the end of the block. The block definition directive have the size parameter, if I want the MY_BLOCK size to grow to 1024, I can use
define block MY_BLOCK with alignment = 32, size = 1024 { section myblock };
And it works well.
However, I want the size to be relative to the original size. So I use
define block MY_BLOCK with alignment = 32, size = __section_size(section myblock) + 64 { section myblock };
This time linker report a error
Error[Lc009]: "__section_size" undefined
Looks like __section_size can be only used in C instead of linker configuration file.
In comparision, ARMGCC we can simply use
. = . + 64
in linker file to achieve this purpose. I am wondering if it is achievable in IAR.
Can someone help me out?

Answer 1

The way to achieve this is to create an empty block with the padding and add it to MY_BLOCK. To ensure that the content and the padding are placed in the order listed in the file we add the attribute fixed order to MY_BLOCK. We also need to add keep { block MY_PADDING }; to the configuration file to tell the linker to include MY_PADDING even though its content is not referenced from the application. The result looks something like this:
define block MY_PADDING with size = 64 {};
define block MY_BLOCK with alignment = 32, fixed order { section myblock,
block MY_PADDING };
keep { block MY_PADDING };
place in CODE_RAM { block MY_BLOCK };