Xiaochu Liu via llvm-dev
2015-Aug-27 00:52 UTC
[llvm-dev] preserve registers across function call
Dear there, I was wondering how to preserve registers (caller saved) across calls. I implemented getCalleeSavedRegs and getCallPreservedMask. But the non-callee-saved registers are still not saved by caller. I want to spill these registers in use on stack right before the call. From my understanding, the register allocator in llvm will do the spill and restoring automatically? Is there anything I was supposed to do to make it happen? Thanks, Xiaochu -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150827/e71882ac/attachment.html>
Marcello Maggioni via llvm-dev
2015-Aug-27 00:58 UTC
[llvm-dev] preserve registers across function call
Is the preserved mask passed down to your Call instruction in LowerCall ? Marcello> On 26 Aug 2015, at 17:52, Xiaochu Liu via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > Dear there, > > I was wondering how to preserve registers (caller saved) across calls. I implemented getCalleeSavedRegs and getCallPreservedMask. But the non-callee-saved registers are still not saved by caller. I want to spill these registers in use on stack right before the call. From my understanding, the register allocator in llvm will do the spill and restoring automatically? Is there anything I was supposed to do to make it happen? > > Thanks, > Xiaochu > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.llvm.org_cgi-2Dbin_mailman_listinfo_llvm-2Ddev&d=BQIGaQ&c=eEvniauFctOgLOKGJOplqw&r=THu9ANfN9LYlQTYNQdmA7D-MsdMl2OioTAKXjMfn7i4&m=T0_ZG8YhyugTycTFs3lQPt6d4mu6n739A4TOI-X1aJ0&s=xBBwHMhNOhAnZr_RXMJN6_kyjY2Wnap1c9aCtrfM7T8&e=-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150826/8ea2c2c6/attachment.html>
Xiaochu Liu via llvm-dev
2015-Aug-27 01:51 UTC
[llvm-dev] preserve registers across function call
Hi Marcello, Thanks for your reply. I will try to pass down the mask! I have one more question. In my backend I return CSR_RegMask in getCallPreservedMask and return CSR_SaveList in getCalleeSavedRegs. Is that a correct setup? I dumped the regmask and found that callee saved regs are marked 1 and non-callee saved regs are 0. Thanks, Xiaochu On Wed, Aug 26, 2015 at 5:58 PM Marcello Maggioni <mmaggioni at apple.com> wrote:> Is the preserved mask passed down to your Call instruction in LowerCall ? > > Marcello > > On 26 Aug 2015, at 17:52, Xiaochu Liu via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > > Dear there, > > I was wondering how to preserve registers (caller saved) across calls. I > implemented getCalleeSavedRegs and getCallPreservedMask. But the > non-callee-saved registers are still not saved by caller. I want to spill > these registers in use on stack right before the call. From my > understanding, the register allocator in llvm will do the spill and > restoring automatically? Is there anything I was supposed to do to make it > happen? > > Thanks, > Xiaochu > > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > > https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.llvm.org_cgi-2Dbin_mailman_listinfo_llvm-2Ddev&d=BQIGaQ&c=eEvniauFctOgLOKGJOplqw&r=THu9ANfN9LYlQTYNQdmA7D-MsdMl2OioTAKXjMfn7i4&m=T0_ZG8YhyugTycTFs3lQPt6d4mu6n739A4TOI-X1aJ0&s=xBBwHMhNOhAnZr_RXMJN6_kyjY2Wnap1c9aCtrfM7T8&e> > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150827/d23075f6/attachment.html>
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