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Pre-Processers for Inlined C Code?
Scott Snell asks: "I have inherited the C code for an embedded system project that has run out of code space. The source code is highly fragmented and the compiler doesnt generate efficient code for stack handling. Ideally I would direct the compiler to 'inline' a lot of the functions but unfortunately it doesnt support the inline keyword. Using macros is dangerous and manually inlining is driving me crazy! What I need is a tool that will take the source files, look for the 'inline' keyword and generate new source files that are inlined. Any ideas?"
Assembler
Here Here!
Perl would be excellent for this job.
11*43+456^2
Unless the functions to inline are *real* small. Think about it- if the function is f bytes in size inlined, and f+a bytes in size as a standalone, and it takes c bytes to call the standalone function, and the function is called in n places, then inlining the function everywhere takes f*n bytes, while calling it takes c*n + f + a bytes. If c f - ((f+a)/n), then it'll be cheaper (require fewer code bytes) to not inline f than to inline f. As n gets large, all you need is c f for it to be a win. How many bytes does it take to call a function? That's your target- if your function is more than a few lines of code (at best) you're probably better off not inlining the function.
I'd actually be inclined to go the other direction- is it possible to uninline things? If the code is doing similiar things in different places, is it possible to write a single function which is instead called in both places?
Barring that, other options include using a different complier- does gcc support your processor? I know gcc doesn't support everything under the sun- many 8- and 16-bit micros and DSPs aren't supported, for example. But if gcc is supported, it does pretty good on the stack space management and automatically inlining. Or you just might have to bite the bullet and spring for a larger rom/flash or larger cpu.
Brian