similar to: Writing static analyzers to detect non-deterministic behavior?

Thanks for your response David. 1) I'm not sure it's do-able. I don't know of any nice way to track whether an ordered walk of an unordered container leaks out into the final output of the program. Only iterating over an unordered container is probably not a sufficient hint (it'd have a high false positive rate to warn on every instance of that) - and I don't have any

Hi all, Last year I had shared with the community my findings about instances of non-determinism in llvm codegen. The major source of which was the iteration of unordered containers resulting in non-deterministic iteration order. In order to uncover such instances we had introduced "reverse iteration" of unordered containers (currently only enabled for SmallPtrSet). I would now

On Thu, Jul 6, 2017 at 8:02 AM, Robinson, Paul via llvm-dev < llvm-dev at lists.llvm.org> wrote: > > > > -----Original Message----- > > From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of > > Grang, Mandeep Singh via llvm-dev > > Sent: Thursday, July 06, 2017 2:56 AM > > To: llvm-dev at lists.llvm.org > > Subject: [llvm-dev]

Everyone, There is non-determinism in LLVM codegen in the following scenarios: 1. Between back-to-back runs of the same LLVM toolchain 2. Between Release vs Release+Asserts toolchains 3. Between Linux vs Windows toolchains The main reasons for the non-determinism in codegen are: 1. Iteration of unordered containers (like SmallPtrSet, DenseMap, etc) where the iteration order is undefined 2.

On Thu, Jul 6, 2017 at 12:34 PM, Sean Silva <chisophugis at gmail.com> wrote: > > > On Thu, Jul 6, 2017 at 10:20 AM, Daniel Berlin via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > >> >> >> On Thu, Jul 6, 2017 at 8:02 AM, Robinson, Paul via llvm-dev < >> llvm-dev at lists.llvm.org> wrote: >> >>> >>> >>>

Everyone, The following patch to reverse iterate SmallPtrSet's has now been merged: https://reviews.llvm.org/D26718 This is how LLVM behavior will change due to this patch: - In LLVM builds with *assertions enabled*, SmallPtrSet's would always be reverse iterated by default. This default behavior can be overridden via the flag "-mllvm -reverse-iterate=<true/false>".

> On 2016-Nov-15, at 15:16, Hal Finkel <hfinkel at anl.gov> wrote: > > ----- Original Message ----- >> From: "Mandeep Singh via llvm-dev Grang" <llvm-dev at lists.llvm.org> >> To: llvm-dev at lists.llvm.org, "mehdi amini" <mehdi.amini at apple.com>, dexonsmith at apple.com, zinob at codeaurora.org >> Sent: Tuesday, November 15, 2016

It is with great sadness that I must tell everyone CMake’s Ninja generator is non-deterministic (https://public.kitware.com/Bug/view.php?id=15968 <https://public.kitware.com/Bug/view.php?id=15968>). I’m not sure if this impacts all versions of CMake, but it certainly impacts all the recent releases. You might ask why this matters? Sadly the non-determinism *does* impact determinism in the

I'm sorry, but I don't think LLDB has any release notes. On Sat, Aug 26, 2017 at 9:49 PM, Kamil Rytarowski <n54 at gmx.com> wrote: > LLDB: > > Switched the NetBSD platform to new remote tracing capable framework. > > Preliminary support for tracing NetBSD(/amd64) processes and core files > with a single thread. > > On 25.08.2017 02:44, Hans Wennborg via

Hi All, I wanted to share a couple of updates on the effort to uncover non-determinism in LLVM through reverse iteration. 1. Reverse iteration has now been enabled for DenseMap (https://reviews.llvm.org/D35043) 2. We have setup a nightly reverse iteration buildbot (http://lab.llvm.org:8011/builders/reverse-iteration). This builds all LLVM targets with reverse iteration ON and runs ninja

On 30 August 2017 at 18:51, David Blaikie via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > > On Tue, Aug 29, 2017 at 11:45 AM Grang, Mandeep Singh via cfe-dev > <cfe-dev at lists.llvm.org> wrote: >> >> Hi All, >> >> I wanted to share a couple of updates on the effort to uncover >> non-determinism in LLVM through reverse iteration. >>

I see that the following test fails if reverse iteration of SmallPtrSet is enabled: /clang/test/SemaCXX/warn-loop-analysis.cpp/ This is because in SemaStmt.cpp we iterate SmallPtrSet and output warnings about the variables not used in the loop. Expected output: /warning: variables 'i', 'j', and 'k' used in loop condition not modified/ Output with reverse iteration:

I haven't tested it, but it looks to me like llvm-profdata merge (well, InstrProfWriter specifically) would not have deterministic output. Certainly the textual output iterates over FunctionData which is a StringMap of SmallDenseMaps, neither of which has deterministic iteration. The binary writing looks like it'd have similar issues - looping through these unordered maps & writing

r327219 added a new wrapper function called *llvm::sort*. If EXPENSIVE_CHECKS is enabled, llvm::sort will randomly shuffle the container before invoking std::sort. This will help uncover non-deterministic ordering of objects having the same key. All occurrences of std::sort have been changed to llvm::sort in llvm/clang/polly repos. Going forward please make sure to avoid use of std::sort and

Hello LLVM-Dev, Today if a user checks out LLVM, configures with no options specified, and builds the result is non-deterministic. Meaning if you clean and build again the binaries are not identical. This impacts all target platforms equally and is caused by the default value of LLVM_ENABLE_TIMESTAMPS being On. I believe this is incorrect behavior, and I’m curious what the wider community

On Thu, Jun 29, 2017 at 7:03 PM Xinliang David Li <davidxl at google.com> wrote: > On Thu, Jun 29, 2017 at 6:27 PM, David Blaikie <dblaikie at gmail.com> wrote: > >> I haven't tested it, but it looks to me like llvm-profdata merge (well, >> InstrProfWriter specifically) would not have deterministic output. >> >> Certainly the textual output iterates

On Tue, Dec 13, 2016 at 6:39 PM, Hans Wennborg <hans at chromium.org> wrote: > On Tue, Dec 13, 2016 at 4:57 PM, Grang, Mandeep Singh via llvm-dev > <llvm-dev at lists.llvm.org> wrote: >> Everyone, >> >> The following patch to reverse iterate SmallPtrSet's has now been merged: >> https://reviews.llvm.org/D26718 >> >> This is how LLVM

On Thu, Jun 29, 2017 at 7:26 PM, David Blaikie <dblaikie at gmail.com> wrote: > > > On Thu, Jun 29, 2017 at 7:03 PM Xinliang David Li <davidxl at google.com> > wrote: > >> On Thu, Jun 29, 2017 at 6:27 PM, David Blaikie <dblaikie at gmail.com> >> wrote: >> >>> I haven't tested it, but it looks to me like llvm-profdata merge (well,

Ping From: Mandeep Singh Grang [mailto:mgrang at codeaurora.org] Sent: Tuesday, February 03, 2015 4:34 PM To: 'llvmdev at cs.uiuc.edu' Cc: 'ghoflehner at apple.com'; 'apazos at codeaurora.org'; mgrang at codeaurora.org Subject: Question on Machine Combiner Pass Hi, In the file lib/CodeGen/MachineCombiner.cpp I see that in the function

Joerg, Referring to your patch https://reviews.llvm.org/rL291172. / switch (MAI->getExceptionHandlingType()) {// // case ExceptionHandling::SjLj:// // case ExceptionHandling::DwarfCFI:// // case ExceptionHandling::ARM:// //*isCFIMoveForDebugging = true;*// //*if (MAI->getExceptionHandlingType() != ExceptionHandling::DwarfCFI)*/*/ /**/ break;/*/ // for (auto &F: