Hello to all,
I am trying to port the old arm project written in C language and partly in assembly that was compiled with the armcc version 4.1. And I must mention I am not an expert on this, still learning, reading the arm documentation.
The selected new compiler is armclang v6.16. For the assembly code I am still using the armasm.
I have read the migration document and the difference between the old arm v5 and new arm v6 compiler and adapted the compiler/linker flags accordingly.
Everything is ok with the build, but the linking is failing with the error:
Error: L6291E: Cannot assign Fixed Execution Region ... Load Address:0x000179b4. Load Address must be greater than or equal to next available Load Address:0x00017f7c.
and what I could see from the map file, using fromelf for specific object file is that the build output from the armclang is bigger than when I used the older compiler. I did some basic test to compile empty functions and found out the following:
- Using old compiler: building the empty function void and non-void creates function of size 2 bytes when I look in the object file using fromelf or in the map file (Memory map of the image)
- Using the new compiler:
- building the empty function void creates function size of 2 bytes
- building the empty non void function creates function size of 4 bytes. (Very strange why additional 2 bytes).
For the code optimization I am using flag -oz as we are not using LTO in the project.
For the moment I am still trying to find out the reason, also checking if I misses any specific compiler flags.
Thank you for any useful information that could help me solve this mystery, Iknerf
I don't think there is more we can suggest here. The underlying optimizers behave quite differently.