search for: funnels

Displaying 20 results from an estimated 120 matches for "funnels".

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2018 Jan 24
3
RFC: Using link-time optimization to eliminate retpolines
...the vtable address into register r10, setting up the other registers for the virtual call and directly calling the branch funnel as if it were a regular function. Because the branch funnel enforces control flow integrity by itself, we can also avoid emitting CFI checks at call sites that use branch funnels when CFI is enabled. To control the layout of vtables and function pointers, we can extend existing mechanisms for controlling layout that are used to implement CFI (see https://clang.llvm.org/docs/ControlFlowIntegrityDesign.html) so that they are also used whenever a branch funnel needs to be cre...
2019 Feb 25
3
funnel shift, select, and poison
We have these transforms from funnel shift to a simpler shift op: // fshl(X, 0, C) -> shl X, C // fshl(X, undef, C) -> shl X, C // fshl(0, X, C) -> lshr X, (BW-C) // fshl(undef, X, C) -> lshr X, (BW-C) These were part of: https://reviews.llvm.org/D54778 In all cases, one operand must be 0 or undef and the shift amount is a constant, so I think these are safe.
2019 Feb 25
2
funnel shift, select, and poison
Don't we need to distinguish funnel shift from the more specific rotate? I'm not seeing how rotate (a single input op shifted by some amount) gets into trouble like funnel shift (two variables concatenated and shifted by some amount). Eg, if in pseudo IR we have: %funnel_shift = fshl %x, %y, %sh ; this is problematic because either x or y can be poison, but we may not touch the poison when
2018 Jan 26
0
RFC: Using link-time optimization to eliminate retpolines
...nto > register r10, setting up the other registers for the virtual call and > directly calling the branch funnel as if it were a regular function. > Because the branch funnel enforces control flow integrity by itself, we can > also avoid emitting CFI checks at call sites that use branch funnels when > CFI is enabled. > > To control the layout of vtables and function pointers, we can extend > existing mechanisms for controlling layout that are used to implement CFI > (see https://clang.llvm.org/docs/ControlFlowIntegrityDesign.html) so that > they are also used whenever a...
2019 Feb 26
2
funnel shift, select, and poison
If I got poison propagation right, it's probably only by luck! Hopefully, the funnel shift bug is fixed here: https://reviews.llvm.org/rL354905 Nuno, IIUC this means that you do *not* need to change the funnel shift semantics in Alive. So I think that means we're still on track to go with John's suggestion that only select and phi can block poison? (I don't know of any
2018 Jan 26
1
RFC: Using link-time optimization to eliminate retpolines
..., setting up the other registers for the virtual call > and directly calling the branch funnel as if it were a regular > function. Because the branch funnel enforces control flow integrity > by itself, we can also avoid emitting CFI checks at call sites that > use branch funnels when CFI is enabled. > > To control the layout of vtables and function pointers, we can > extend existing mechanisms for controlling layout that are used to > implement CFI (see > https://clang.llvm.org/docs/ControlFlowIntegrityDesign.html > <https://clang....
2019 Feb 25
4
funnel shift, select, and poison
There's a question about the behavior of funnel shift [1] + select and poison here that reminds me of previous discussions about select and poison [2]: https://github.com/AliveToolkit/alive2/pull/32#discussion_r257528880 Example: define i8 @fshl_zero_shift_guard(i8 %x, i8 %y, i8 %sh) { %c = icmp eq i8 %sh, 0 %f = fshl i8 %x, i8 %y, i8 %sh %s = select i1 %c, i8 %x, i8 %f ; shift amount is 0
2018 Jul 02
2
Rotates, once again
On 7/2/2018 3:16 PM, Sanjay Patel wrote: > I also agree that the per-element rotate for vectors is what we want for > this intrinsic. > > So I have this so far: > > declare i32 @llvm.catshift.i32(i32 %a, i32 %b, i32 %shift_amount) > declare <2 x i32> @llvm.catshift.v2i32(<2 x i32> %a, <2 x i32> %b, <2 x i32> %shift_amount) > > For
2009 Jun 12
0
funnel plots
for the function funnelplot(), how do I include 95% confidence intervals for the effect estimate ( ie. / \ )? -- View this message in context: http://www.nabble.com/funnel-plots-tp24003106p24003106.html Sent from the R help mailing list archive at Nabble.com.
2018 Dec 18
2
RFE: OpenSSH Support for PKCS11 Funneling to PAM for Kerberos/PKINIT
I know OpenSSH currently supports PKCS11 devices (such as smartcards) for publickey authentication, but I would love to see PKCS11 extended further. It is currently possible to perform PKCS11 certificate authentication, via pam_krb5.so (on Linux at least and likely something similar on other *NIX) which allows smartcard auth to a Kerberos (including AD) server, where a TGT can also be granted.
2019 Feb 25
2
funnel shift, select, and poison
On 2/25/2019 11:15 AM, John Regehr via llvm-dev wrote: > I'd just like to add that the general question here is "where does > poison stop propagating" and this question needs to be definitively > answered by this community. Does a call stop poison? Whatever the decision is may be contradicted after inlining, so what should such a call return? A superposition of poison
2019 Feb 25
2
funnel shift, select, and poison
On 2/25/2019 12:28 PM, John Regehr via llvm-dev wrote: > Poison has to propagate through calls and loads/stores, or else > basically nothing works. Consider this: %v0 = call i32 @foo(poison) nounwind/readnone store i32 %v0, i32* %valid_address If we assume that poison propagates through calls, we could then optimize this to %v0 = poison store poison, i32* %valid_address If
2019 Feb 25
2
funnel shift, select, and poison
On 2/25/2019 1:24 PM, John Regehr via llvm-dev wrote: > > This is a sound transformation only if foo() returns poison when it is > called with poison as an argument. Then how do you interpret "poison has to propagate through calls"? A typical analysis of a function will either see a call or the inlined body. If "call(poison)" cannot be assumed to be a poison, then
2009 Mar 27
2
Physical or Statistical Explanation for the "Funnel" Plot?
The R code below produces (after running for a few minutes on a decent computer) the plot shown at the following location: http://n2.nabble.com/Is-there-a-physical-and-quantitative-explanation-for-this-plot--td2542321.html I'm just taking the mean of a given set of random variables, where the set size is increased. There appears to be a quick convergence and then a pretty steady variance
2012 Mar 28
0
Major update: meta version 2.0-0
Version 2.0-0 of meta (an R package for meta-analysis) is now available on CRAN. Changes are described below. Yours, Guido Major revision R package meta linked to R package metafor by Wolfgang Viechtbauer to provide additional statistical methods, e.g. meta-regression and other estimates for tau-squared (REML, ...) New functions: - metareg (meta-regression) - metabias
2012 Mar 28
0
Major update: meta version 2.0-0
Version 2.0-0 of meta (an R package for meta-analysis) is now available on CRAN. Changes are described below. Yours, Guido Major revision R package meta linked to R package metafor by Wolfgang Viechtbauer to provide additional statistical methods, e.g. meta-regression and other estimates for tau-squared (REML, ...) New functions: - metareg (meta-regression) - metabias
2019 Feb 26
2
funnel shift, select, and poison
> Transforms/InstCombine/select.ll > ================================ > define i1 @trueval_is_true(i1 %C, i1 %X) { >  %R = select i1 %C, i1 1, i1 %X >  ret i1 %R > } > => > define i1 @trueval_is_true(i1 %C, i1 %X) { >  %R = or i1 %C, %X >  ret i1 %R > } > ERROR: Target is more poisonous than source (when %C = #x1 & %X = poison) > > (there are
2005 Mar 29
1
External voice channels pack up
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2018 Dec 18
2
RFE: OpenSSH Support for PKCS11 Funneling to PAM for Kerberos/PKINIT
Alon, I should have provided more background. You are assuming that I could perform the PKINIT prior to connecting to the SSH server. In this case (and others) there is an interest in not exposing the kerberos servers to the world and thus someone connecting remotely would not be able to obtain a TGT or do a PKINIT. The goal would be for SSH to handle all the auth and only after connecting to
2007 Sep 10
5
Asterisk Manager API - Originate command
Hi all, Just ran into some issue with the originate AMI command. It seems that there is a limit of around 120 calls I can place with the originate command simutanously. By that I mean sending Asterisk a lot of originate command very fast. Anyone know if there is a limitation? Thnx. -------------- next part -------------- An HTML attachment was scrubbed... URL: