Description of problem: The "used" attribute does not cause a local static to be emitted to the .s/.o file Version-Release number of selected component (if applicable): gcc-4.1.1-24 How reproducible: All the time Steps to Reproduce: 1.compile the attached file with "gcc -O -S t.c" 2. 3. Actual results: no evidence of "bar" in the output Expected results: "bar" emitted in some form Additional info: I'm actually using this in the kernel to emit things into a section, so it doesn't matter what actual name the variable gets.
Created attachment 137451 [details] C source
As a workaround, I'm adding asm("" : : "m" (bar)) to force a reference to the variable. Unfortunately, this seems to provoke some other bug when I use it in the kernel; I get references to labels which don't exist. I'll try to winnow something down to file a separate bug.
Created attachment 137452 [details] .s output file I get
I don't think that's a bug, local statics are very different from global ones. For global statics you know their name and can reference it from asm, for local statics if you don't reference them, you can't guess their name. Also, this is nothing Fedora gcc specific, upstream GCC behaves the same way, so if you insist this is a GCC bug, you should file it to upstream instead (http://gcc.gnu.org/bugzilla/).
As I said in the original report: "I'm actually using this in the kernel to emit things into a section, so it doesn't matter what actual name the variable gets." I want to emit a record for each BUG() into the __bug_table section; since BUG is necessarily used within code, everything that happens within it needs to have some kind of local scope. I thought I'd report it here in case there was some local change, but I'll report it upstream.