Should static libraries be always built with same compiler options as the application?

Question

We have a reusable library which gets delivered across to multiple products. Most of the products are in VxWorks and use gcc compiler. But, each of them will be on different architectures like PPC, MIPS and in PPC itself there are more types like 8531, 8620 etc.

Currently, I am building static libs for each of these boards seperately and provide. Is there anyway that a common library can be built, which can be used across all these different architectures?

Also, currently I try to ensure that compiler options are same as that of the products. Is it necessary? Is there any information available in the internet which classifies which options are important to maintained same for static libraries and applications?

Answer 1

1. No there is no other way - you must built the libraries (static or not) for each platform. As you probably already know static library is really just a container storing a buch of object files. Each object file contains binary code specific to platform that the library was built for (read: different set of assembly instructions).
2. Yes, keeping the compiler options the same when you are building a library and the binary (program) that uses it the same is a very good practice. This way you are avoiding potentially very nasty problems. Some optimization options are binary incompatible (e.g.: you may compile a function in a library with a optimization that will cause it to return (or expect) a data by register), but your main program may expect that the function returns it by address on stack - big trouble.