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Recently I had to write a program for an embedded Linux router which ran on a MIPS architecture and had a 2MB flash. I only had about 40kb of space to fit the

Recently I had to write a program for an embedded Linux router which ran on a MIPS architecture and had a 2MB flash. I only had about 40kb of space to fit the application on. I was able to get a binary that was compiling to more than 1.5mb down to 20kb through using a combination of gcc tricks like separating data and code sections, eliminating unused sections, statically linking some libraries and dynamically linking against others. It once again gave me immense appreciation for having a language and toolchain that can give you this power for those 1% of problems your career might depend on. For amusement, the relevant section of the Makefile I ended up with: LIB_NL_MIPS_STATIC=libs/libnl_mips_static CFLAGS=-Os -I$(LIB_NL_BASE)/include -ffunction-sections -fdata-sections -Wall -Wextra -MD LDFLAGS=-Wl,--gc-sections -L$(LIB_NL_MIPS_STATIC) -Lbuild -Wl,-Bstatic -lmon -lnl-3 -lnl-route-3 -Wl,-Bdynamic -lpthread -lm -lc I'm unsure how many other languages/toolchains give you that sort of flexibility down to the linking level. Also it's self contained and doesn't require some kind of "virtual machine" or interpreter to run it.

userbinator 13y ago
That makes me wonder why "eliminating unused sections" isn't a default, as it feels like the compiler is doing a lot of unnecessary work if it's generating 1.5M of output that actually has only 20k of useful stuff in it.
- laichzeit0 13y ago
  It's only that big because of static linking. Typically you're never statically linking your applications, but in this case it's necessary if you want to use libraries but only want the space-overhead from the code and data you use from the libraries. It reminds me of a quote I read in the book, Expert C Programming: Deep C Secrets (an excellent book on C btw), that read: "Static linking is now functionally obsolete, and should be allowed to rest in peace." I kinda chuckled a bit when I saw.
  - uggedal 13y ago
    It's far from obselete: http://sta.li/faq http://sta.li/faq
pjmlp 13y ago
> I'm unsure how many other languages/toolchains give you that sort of flexibility down to the linking level. Also it's self contained and doesn't require some kind of "virtual machine" or interpreter to run it. Almost every language that has an ahead of time compiler to native code.

userbinator 13y ago

That makes me wonder why "eliminating unused sections" isn't a default, as it feels like the compiler is doing a lot of unnecessary work if it's generating 1.5M of output that actually has only 20k of useful stuff in it.

laichzeit0 13y ago
It's only that big because of static linking. Typically you're never statically linking your applications, but in this case it's necessary if you want to use libraries but only want the space-overhead from the code and data you use from the libraries. It reminds me of a quote I read in the book, Expert C Programming: Deep C Secrets (an excellent book on C btw), that read: "Static linking is now functionally obsolete, and should be allowed to rest in peace." I kinda chuckled a bit when I saw.
- uggedal 13y ago
  It's far from obselete: http://sta.li/faq http://sta.li/faq

pjmlp 13y ago

> I'm unsure how many other languages/toolchains give you that sort of flexibility down to the linking level. Also it's self contained and doesn't require some kind of "virtual machine" or interpreter to run it. Almost every language that has an ahead of time compiler to native code.