I'm migrating from arm compiler 5 to armclang and I'm struggling with placing functions in RAM.
I tried using what this page suggests - https://www.keil.com/support/docs/3228.htm - and it works, if LTO is disabled.
If I enable LTO and set optimization level to -Oz, function gets inlined in 'normal' flash-function. Using -fno-inline or __attribute__((noinline)) doesn't affect this.
How can I prevent this?
Hi Roman, this is the nature of LTO (link time optimization) - you are asking the linker to put this function in the most optimal place based on how other objects interact with it. LTO will result in a single large object with all the LTO'd code together (this is most easily seen by the --info sizes linker output).
The solution is to disable LTO for this source file (-fno-lto) - you can continue to use LTO for other files.
Unfortunately that didn't help; functions still got inlined
Does the --info sizes linker output show that this function('s object) is linked in independently or the large LTO'ed object?
From there, does the scatter file show this object being placed at the expected address?
Oh dear, I'm so sorry. Somehow I got all mixed up; the function wasn't inlined in the first place, even with LTO enabled everywhere.
I just updated to Keil 5.34 and there -LTO really does break ramfunctions. Howerver disabling lto for one file as you suggested - works!
View all questions in Arm Compilers forum