Chandler Carruth via llvm-dev
2016-Apr-18 22:25 UTC
[llvm-dev] Move InlineCost.cpp out of Analysis?
On Mon, Apr 18, 2016 at 3:20 PM Easwaran Raman <eraman at google.com> wrote:> On Mon, Apr 18, 2016 at 3:00 PM, Chandler Carruth via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > >> On Mon, Apr 18, 2016 at 2:48 PM Hal Finkel <hfinkel at anl.gov> wrote: >> >>> >>> >>> ------------------------------ >>> >>> *From: *"Xinliang David Li" <davidxl at google.com> >>> >>> On Mon, Apr 18, 2016 at 2:33 PM, Mehdi Amini <mehdi.amini at apple.com> >>> wrote: >>>> >>>> In the current case at stake: the issue is that we can't make the >>>> Analysis library using anything from the ProfileData library. Conceptually >>>> there is a problem IMO. >>>> >>> >>> >>> Yes -- this is a very good point. >>> >>> Independent of anything else, +1. >>> >> >> The design of ProfileData and reading profile information in the entire >> middle end had a really fundamental invariant that folks seem to have lost >> track of: >> >> a) There is exactly *one* way to get at profile information from general >> analyses and transforms: a dedicated analysis pass that manages access to >> the profile info. >> >> b) There is exactly *one* way for this analysis to compute this >> information from an *external* profile source: profile metadata attached to >> the IR. >> >> c) There could be many external profile sources, but all of them should >> be read and then translated into metadata annotations on the IR so that >> serialization / deserialization preserve them in a common format and we can >> reason about how they work. >> >> >> This layering is why it is only a transform that accesses ProfileData -- >> it is responsible for annotating the IR and nothing else. Then the >> analysis uses these annotations and never reads the data directly. >> >> I think this is a really important separation of concerns as it ensures >> that we don't get an explosion of different analyses supporting various >> different subsets of profile sources. >> >> >> Now, the original design only accounted for profile information *within* >> a function body, clearly it needs to be extended to support intraprocedural >> information. But I would still expect that to follow a similar layering >> where we first read the data into IR annotations, then have an analysis >> pass (this time a module analysis pass in all likelihood) that brokers >> access to these annotations through an API that can do intelligent things >> like synthesizing it from the "cold" attribute or whatever when missing. >> >> > Invariants b) and c) above are still true, but a) is not since InlineCost > directly calls ProfileSummary instead of through an analysis pass. >Not quite -- ProfileSummary seems to only exist in the profile *reading* code, so it isn't *just* an annotation on the IR. I think the problem here is that we have failed to build a proper separate abstraction around the interprocedural profile data that is extracted from IR annotations. That abstraction should have nothing to do with reading profile data and so shouldn't live in the ProifileData library, it should (IMO) live in the Analysis library. I'll add a module level pass as you suggest, but that still needs> breaking the ProfileData->Analysis dependence chain. >Well, this will also re-highlight the fundamental pass manager problem as you won't have easy access to this analysis pass.> > - Easwaran > >> -Chandler >> > >> _______________________________________________ >> LLVM Developers mailing list >> llvm-dev at lists.llvm.org >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >> >>-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20160418/9cf669a4/attachment.html>
Hal Finkel via llvm-dev
2016-Apr-18 22:31 UTC
[llvm-dev] Move InlineCost.cpp out of Analysis?
----- Original Message -----> From: "Chandler Carruth" <chandlerc at gmail.com> > To: "Easwaran Raman" <eraman at google.com> > Cc: "Hal Finkel" <hfinkel at anl.gov>, "Xinliang David Li" > <davidxl at google.com>, "via llvm-dev" <llvm-dev at lists.llvm.org> > Sent: Monday, April 18, 2016 5:25:03 PM > Subject: Re: [llvm-dev] Move InlineCost.cpp out of Analysis?> On Mon, Apr 18, 2016 at 3:20 PM Easwaran Raman < eraman at google.com > > wrote:> > On Mon, Apr 18, 2016 at 3:00 PM, Chandler Carruth via llvm-dev < > > llvm-dev at lists.llvm.org > wrote: >> > > On Mon, Apr 18, 2016 at 2:48 PM Hal Finkel < hfinkel at anl.gov > > > > wrote: > > >> > > > > From: "Xinliang David Li" < davidxl at google.com > > > > > > > > > > >> > > > > On Mon, Apr 18, 2016 at 2:33 PM, Mehdi Amini < > > > > > mehdi.amini at apple.com > > > > > > wrote: > > > > > > > > > > > > > > > > In the current case at stake: the issue is that we can't > > > > > > make > > > > > > the > > > > > > Analysis library using anything from the ProfileData > > > > > > library. > > > > > > Conceptually there is a problem IMO. > > > > > > > > > > > > > > > > > > > > Yes -- this is a very good point. > > > > > > > > > > > > > > Independent of anything else, +1. > > > > > >> > > The design of ProfileData and reading profile information in the > > > entire middle end had a really fundamental invariant that folks > > > seem > > > to have lost track of: > > >> > > a) There is exactly *one* way to get at profile information from > > > general analyses and transforms: a dedicated analysis pass that > > > manages access to the profile info. > > >> > > b) There is exactly *one* way for this analysis to compute this > > > information from an *external* profile source: profile metadata > > > attached to the IR. > > >> > > c) There could be many external profile sources, but all of them > > > should be read and then translated into metadata annotations on > > > the > > > IR so that serialization / deserialization preserve them in a > > > common > > > format and we can reason about how they work. > > >> > > This layering is why it is only a transform that accesses > > > ProfileData > > > -- it is responsible for annotating the IR and nothing else. Then > > > the analysis uses these annotations and never reads the data > > > directly. > > >> > > I think this is a really important separation of concerns as it > > > ensures that we don't get an explosion of different analyses > > > supporting various different subsets of profile sources. > > >> > > Now, the original design only accounted for profile information > > > *within* a function body, clearly it needs to be extended to > > > support > > > intraprocedural information. But I would still expect that to > > > follow > > > a similar layering where we first read the data into IR > > > annotations, > > > then have an analysis pass (this time a module analysis pass in > > > all > > > likelihood) that brokers access to these annotations through an > > > API > > > that can do intelligent things like synthesizing it from the > > > "cold" > > > attribute or whatever when missing. > > >> > Invariants b) and c) above are still true, but a) is not since > > InlineCost directly calls ProfileSummary instead of through an > > analysis pass. > > Not quite -- ProfileSummary seems to only exist in the profile > *reading* code, so it isn't *just* an annotation on the IR.> I think the problem here is that we have failed to build a proper > separate abstraction around the interprocedural profile data that is > extracted from IR annotations. That abstraction should have nothing > to do with reading profile data and so shouldn't live in the > ProifileData library, it should (IMO) live in the Analysis library.> > I'll add a module level pass as you suggest, but that still needs > > breaking the ProfileData->Analysis dependence chain. > > Well, this will also re-highlight the fundamental pass manager > problem as you won't have easy access to this analysis pass.Could this be an immutable pass? -Hal> > - Easwaran > > > > -Chandler > > > > > > _______________________________________________ > > > > > > LLVM Developers mailing list > > > > > > llvm-dev at lists.llvm.org > > > > > > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev > > >-- Hal Finkel Assistant Computational Scientist Leadership Computing Facility Argonne National Laboratory -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20160418/b32d9223/attachment.html>
Xinliang David Li via llvm-dev
2016-Apr-18 22:51 UTC
[llvm-dev] Move InlineCost.cpp out of Analysis?
On Mon, Apr 18, 2016 at 3:31 PM, Hal Finkel <hfinkel at anl.gov> wrote:> > > ------------------------------ > > *From: *"Chandler Carruth" <chandlerc at gmail.com> > *To: *"Easwaran Raman" <eraman at google.com> > *Cc: *"Hal Finkel" <hfinkel at anl.gov>, "Xinliang David Li" < > davidxl at google.com>, "via llvm-dev" <llvm-dev at lists.llvm.org> > *Sent: *Monday, April 18, 2016 5:25:03 PM > *Subject: *Re: [llvm-dev] Move InlineCost.cpp out of Analysis? > > On Mon, Apr 18, 2016 at 3:20 PM Easwaran Raman <eraman at google.com> wrote: > >> On Mon, Apr 18, 2016 at 3:00 PM, Chandler Carruth via llvm-dev < >> llvm-dev at lists.llvm.org> wrote: >> >>> On Mon, Apr 18, 2016 at 2:48 PM Hal Finkel <hfinkel at anl.gov> wrote: >>> >>>> >>>> >>>> ------------------------------ >>>> >>>> *From: *"Xinliang David Li" <davidxl at google.com> >>>> >>>> On Mon, Apr 18, 2016 at 2:33 PM, Mehdi Amini <mehdi.amini at apple.com> >>>> wrote: >>>>> >>>>> In the current case at stake: the issue is that we can't make the >>>>> Analysis library using anything from the ProfileData library. Conceptually >>>>> there is a problem IMO. >>>>> >>>> >>>> >>>> Yes -- this is a very good point. >>>> >>>> Independent of anything else, +1. >>>> >>> >>> The design of ProfileData and reading profile information in the entire >>> middle end had a really fundamental invariant that folks seem to have lost >>> track of: >>> >>> a) There is exactly *one* way to get at profile information from general >>> analyses and transforms: a dedicated analysis pass that manages access to >>> the profile info. >>> >>> b) There is exactly *one* way for this analysis to compute this >>> information from an *external* profile source: profile metadata attached to >>> the IR. >>> >>> c) There could be many external profile sources, but all of them should >>> be read and then translated into metadata annotations on the IR so that >>> serialization / deserialization preserve them in a common format and we can >>> reason about how they work. >>> >>> >>> This layering is why it is only a transform that accesses ProfileData -- >>> it is responsible for annotating the IR and nothing else. Then the >>> analysis uses these annotations and never reads the data directly. >>> >>> I think this is a really important separation of concerns as it ensures >>> that we don't get an explosion of different analyses supporting various >>> different subsets of profile sources. >>> >>> >>> Now, the original design only accounted for profile information *within* >>> a function body, clearly it needs to be extended to support intraprocedural >>> information. But I would still expect that to follow a similar layering >>> where we first read the data into IR annotations, then have an analysis >>> pass (this time a module analysis pass in all likelihood) that brokers >>> access to these annotations through an API that can do intelligent things >>> like synthesizing it from the "cold" attribute or whatever when missing. >>> >>> >> Invariants b) and c) above are still true, but a) is not since InlineCost >> directly calls ProfileSummary instead of through an analysis pass. >> > > Not quite -- ProfileSummary seems to only exist in the profile *reading* > code, so it isn't *just* an annotation on the IR. > > I think the problem here is that we have failed to build a proper separate > abstraction around the interprocedural profile data that is extracted from > IR annotations. That abstraction should have nothing to do with reading > profile data and so shouldn't live in the ProifileData library, it should > (IMO) live in the Analysis library. > > I'll add a module level pass as you suggest, but that still needs >> breaking the ProfileData->Analysis dependence chain. >> > > Well, this will also re-highlight the fundamental pass manager problem as > you won't have easy access to this analysis pass. > > Could this be an immutable pass? >I think yes, but this is independent of the issue at hand -- removing the circular dependency introduced (due to dep of cov mapping on bitcode writer ....). Easwaran is working on that without requiring moving InlineCostAnalysis. David> > > -Hal > > > >> >> - Easwaran >> >>> -Chandler >>> >> >>> _______________________________________________ >>> LLVM Developers mailing list >>> llvm-dev at lists.llvm.org >>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >>> >>> > > > -- > Hal Finkel > Assistant Computational Scientist > Leadership Computing Facility > Argonne National Laboratory >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20160418/30c9afec/attachment-0001.html>
Easwaran Raman via llvm-dev
2016-Apr-18 23:05 UTC
[llvm-dev] Move InlineCost.cpp out of Analysis?
On Mon, Apr 18, 2016 at 3:25 PM, Chandler Carruth <chandlerc at gmail.com> wrote:> On Mon, Apr 18, 2016 at 3:20 PM Easwaran Raman <eraman at google.com> wrote: > >> On Mon, Apr 18, 2016 at 3:00 PM, Chandler Carruth via llvm-dev < >> llvm-dev at lists.llvm.org> wrote: >> >>> On Mon, Apr 18, 2016 at 2:48 PM Hal Finkel <hfinkel at anl.gov> wrote: >>> >>>> >>>> >>>> ------------------------------ >>>> >>>> *From: *"Xinliang David Li" <davidxl at google.com> >>>> >>>> On Mon, Apr 18, 2016 at 2:33 PM, Mehdi Amini <mehdi.amini at apple.com> >>>> wrote: >>>>> >>>>> In the current case at stake: the issue is that we can't make the >>>>> Analysis library using anything from the ProfileData library. Conceptually >>>>> there is a problem IMO. >>>>> >>>> >>>> >>>> Yes -- this is a very good point. >>>> >>>> Independent of anything else, +1. >>>> >>> >>> The design of ProfileData and reading profile information in the entire >>> middle end had a really fundamental invariant that folks seem to have lost >>> track of: >>> >>> a) There is exactly *one* way to get at profile information from general >>> analyses and transforms: a dedicated analysis pass that manages access to >>> the profile info. >>> >>> b) There is exactly *one* way for this analysis to compute this >>> information from an *external* profile source: profile metadata attached to >>> the IR. >>> >>> c) There could be many external profile sources, but all of them should >>> be read and then translated into metadata annotations on the IR so that >>> serialization / deserialization preserve them in a common format and we can >>> reason about how they work. >>> >>> >>> This layering is why it is only a transform that accesses ProfileData -- >>> it is responsible for annotating the IR and nothing else. Then the >>> analysis uses these annotations and never reads the data directly. >>> >>> I think this is a really important separation of concerns as it ensures >>> that we don't get an explosion of different analyses supporting various >>> different subsets of profile sources. >>> >>> >>> Now, the original design only accounted for profile information *within* >>> a function body, clearly it needs to be extended to support intraprocedural >>> information. But I would still expect that to follow a similar layering >>> where we first read the data into IR annotations, then have an analysis >>> pass (this time a module analysis pass in all likelihood) that brokers >>> access to these annotations through an API that can do intelligent things >>> like synthesizing it from the "cold" attribute or whatever when missing. >>> >>> >> Invariants b) and c) above are still true, but a) is not since InlineCost >> directly calls ProfileSummary instead of through an analysis pass. >> > > Not quite -- ProfileSummary seems to only exist in the profile *reading* > code, so it isn't *just* an annotation on the IR. >Sorry, I'm lost here. There is an IR annotation (module flag) called ProfileSummary and this data is represented in memory by the ProfileSummary class. . This class provides methods to serialize/de-serialize this data into/from metadata. This class has methods to compute this summary, but this is used only by the profile readers and writers. I am not sure what you mean by "it isn't just* an annotation on the IR". - Easwaran> > I think the problem here is that we have failed to build a proper separate > abstraction around the interprocedural profile data that is extracted from > IR annotations. That abstraction should have nothing to do with reading > profile data and so shouldn't live in the ProifileData library, it should > (IMO) live in the Analysis library. > > I'll add a module level pass as you suggest, but that still needs >> breaking the ProfileData->Analysis dependence chain. >> > > Well, this will also re-highlight the fundamental pass manager problem as > you won't have easy access to this analysis pass. > > > >> >> - Easwaran >> >>> -Chandler >>> >> >>> _______________________________________________ >>> LLVM Developers mailing list >>> llvm-dev at lists.llvm.org >>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >>> >>>-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20160418/a4a8f5d1/attachment.html>
Philip Reames via llvm-dev
2016-Apr-18 23:36 UTC
[llvm-dev] Move InlineCost.cpp out of Analysis?
On 04/18/2016 04:05 PM, Easwaran Raman via llvm-dev wrote:> > > On Mon, Apr 18, 2016 at 3:25 PM, Chandler Carruth <chandlerc at gmail.com > <mailto:chandlerc at gmail.com>> wrote: > > On Mon, Apr 18, 2016 at 3:20 PM Easwaran Raman <eraman at google.com > <mailto:eraman at google.com>> wrote: > > On Mon, Apr 18, 2016 at 3:00 PM, Chandler Carruth via llvm-dev > <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote: > > On Mon, Apr 18, 2016 at 2:48 PM Hal Finkel > <hfinkel at anl.gov <mailto:hfinkel at anl.gov>> wrote: > > > > ------------------------------------------------------------------------ > > *From: *"Xinliang David Li" <davidxl at google.com > <mailto:davidxl at google.com>> > > On Mon, Apr 18, 2016 at 2:33 PM, Mehdi Amini > <mehdi.amini at apple.com > <mailto:mehdi.amini at apple.com>> wrote: > > In the current case at stake: the issue is > that we can't make the Analysis library using > anything from the ProfileData library. > Conceptually there is a problem IMO. > > > > Yes -- this is a very good point. > > Independent of anything else, +1. > > > The design of ProfileData and reading profile information > in the entire middle end had a really fundamental > invariant that folks seem to have lost track of: > > a) There is exactly *one* way to get at profile > information from general analyses and transforms: a > dedicated analysis pass that manages access to the profile > info. > > b) There is exactly *one* way for this analysis to compute > this information from an *external* profile source: > profile metadata attached to the IR. > > c) There could be many external profile sources, but all > of them should be read and then translated into metadata > annotations on the IR so that serialization / > deserialization preserve them in a common format and we > can reason about how they work. > > > This layering is why it is only a transform that accesses > ProfileData -- it is responsible for annotating the IR and > nothing else. Then the analysis uses these annotations and > never reads the data directly. > > I think this is a really important separation of concerns > as it ensures that we don't get an explosion of different > analyses supporting various different subsets of profile > sources. > > > Now, the original design only accounted for profile > information *within* a function body, clearly it needs to > be extended to support intraprocedural information. But I > would still expect that to follow a similar layering where > we first read the data into IR annotations, then have an > analysis pass (this time a module analysis pass in all > likelihood) that brokers access to these annotations > through an API that can do intelligent things like > synthesizing it from the "cold" attribute or whatever when > missing. > > > Invariants b) and c) above are still true, but a) is not since > InlineCost directly calls ProfileSummary instead of through an > analysis pass. > > > Not quite -- ProfileSummary seems to only exist in the profile > *reading* code, so it isn't *just* an annotation on the IR. > > Sorry, I'm lost here. There is an IR annotation (module flag) called > ProfileSummary and this data is represented in memory by the > ProfileSummary class. . This class provides methods to > serialize/de-serialize this data into/from metadata. This class has > methods to compute this summary, but this is used only by the profile > readers and writers. I am not sure what you mean by "it isn't just* an > annotation on the IR".If this is true, why is this class currently part of ProfileData? Shouldn't this live in IR? Or to phrase this differently, why is an "analysis" over IR mixed in with the parsing code?> > - Easwaran > > > I think the problem here is that we have failed to build a proper > separate abstraction around the interprocedural profile data that > is extracted from IR annotations. That abstraction should have > nothing to do with reading profile data and so shouldn't live in > the ProifileData library, it should (IMO) live in the Analysis > library. > > I'll add a module level pass as you suggest, but that still > needs breaking the ProfileData->Analysis dependence chain. > > > Well, this will also re-highlight the fundamental pass manager > problem as you won't have easy access to this analysis pass. > > > - Easwaran > > -Chandler > > > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev > > > > > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20160418/cb4e593e/attachment.html>