How can I run GCC/Clang for static analysis? (warnings only)

Question

Without compiling code, I would like GCC or Clang to report warnings.
Is it possible to run the compiler for static analysis only?
I can't find a way to pass the compiler warning flags and tell it not to compile.

edit: just found that clang has a static analyser

Answer 1

Both GCC and Clang have an option -fsyntax-only that makes the compiler only perform syntax checking without any actual compilation.

Answer 2

In addition to the other replies, gcc is doing some analysis during compilation (and even during some optimization passes). So you could discard the generated code and still get all the warnings with e.g. gcc -Wall -O -c code.c -o /dev/null

Notice that you could extend GCC with your additional passes doing some additional, application specific, checks and warnings, e.g. with MELT (a high level domain specific language to extend GCC).

If you want strong static analysis and are willing to give additional annotations for that purpose consider also Frama C.