Yes don't compile with -fPIC or compile with -ftls-model=local-exec .
Thanks, Andrew Pinski ________________________________ From: linaro-toolchain-bounces@lists.linaro.org linaro-toolchain-bounces@lists.linaro.org on behalf of Vitali Sokhin vitali.sokhin@gmail.com Sent: Sunday, July 14, 2013 12:21 AM To: linaro-toolchain@lists.linaro.org Subject: How to make gcc generate optimized code for statically linked TLS
Hello,
I use gcc-linaro-aarch64-linux-gnu-4.8 to compile my C code with thread-local variables.
Here is an example of my C code:
__thread u32 threadedVar; void test(void) { threadedVar = 0xDEAD; }
gcc produces the following assembly to access my threaded variable:
threadedVar = 0xDEAD; 72b0: d00000c0 adrp x0, 21000 72b4: f945ac00 ldr x0, [x0,#2904] 72b8: d503201f nop 72bc: d503201f nop 72c0: d53bd041 mrs x1, tpidr_el0 72c4: 529bd5a2 movz w2, #0xdead 72c8: b8206822 str w2, [x1,x0]
This assembly fits dynamically linked code, but in my case I have statically linked application that does not load any additional modules. Since I have exactly one TLS block containing all thread-local variable gcc should be able to calculate the offset at link time.
Can I make gcc to produce the following assembly ?
threadedVar = 0xDEAD; 72c0: d53bd041 mrs x1, tpidr_el0 72c4: 529bd5a2 movz w2, #0xdead 72c8: b8206822 str w2, [x1,#offset_to_threadedVar]
Thank you, Vitali