On 03/13/2015 06:04 PM, Marc Gauthier wrote:
Other than the required 16-byte stack alignment, there's nothing in
the ABI that requires these extra 16 bytes. Perhaps there was a bad
implementation of the alloca exception handler at some point a long
time ago that prompted the extra 16 bytes?
On Fri, Mar 13, 2015 at 8:08 PM, augustine.sterl...@gmail.com
augustine.sterl...@gmail.com wrote:
On Fri, Mar 13, 2015 at 10:04 AM, Marc Gauthier m...@cadence.com wrote:
Other than the required 16-byte stack alignment, there's nothing in
the ABI that requires these extra 16 bytes. Perhaps
On Fri, Mar 13, 2015 at 11:36:47PM +0300, Max Filippov wrote:
2. alloca seems to make an additional 16-bytes padding to each stack
allocation: alloca(1) results in moving sp down by 32 bytes, alloca(17)
moves it by 48 bytes, etc.
This sounds like PR 50938, 47353, 34548, maybe more?
On Fri, Mar 13, 2015 at 05:54:48PM +0300, Max Filippov wrote:
2. alloca seems to make an additional 16-bytes padding to each stack
allocation: alloca(1) results in moving sp down by 32 bytes, alloca(17)
moves it by 48 bytes, etc.
This sounds like PR 50938, 47353, 34548, maybe more?
On Fri, Mar 13, 2015 at 11:18 PM, Segher Boessenkool
seg...@kernel.crashing.org wrote:
On Fri, Mar 13, 2015 at 05:54:48PM +0300, Max Filippov wrote:
2. alloca seems to make an additional 16-bytes padding to each stack
allocation: alloca(1) results in moving sp down by 32 bytes, alloca(17)
Hi Sterling,
I've got an issue building gdb for xtensa linux with gcc, reported it here:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65416
Looking at it I've got two questions, can you help me with them?
1. in windowed ABI stack pointer update is always split into two opcodes:
add and movsp.
On Fri, Mar 13, 2015 at 7:54 AM, Max Filippov jcmvb...@gmail.com wrote:
1. in windowed ABI stack pointer update is always split into two opcodes:
add and movsp. How gcc optimization passes are supposed to know that
'movsp' is related to 'add' and that stack allocation is complete only after
augustine.sterl...@gmail.com wrote:
On Fri, Mar 13, 2015 at 7:54 AM, Max Filippov jcmvb...@gmail.com wrote:
[...]
2. alloca seems to make an additional 16-bytes padding to each stack
allocation: alloca(1) results in moving sp down by 32 bytes,
alloca(17)
moves it by 48 bytes, etc.
On Fri, Mar 13, 2015 at 10:04 AM, Marc Gauthier m...@cadence.com wrote:
Other than the required 16-byte stack alignment, there's nothing in
the ABI that requires these extra 16 bytes. Perhaps there was a bad
implementation of the alloca exception handler at some point a long
time ago that
