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<div class="moz-cite-prefix">On 05/26/2017 10:06 PM, Zachary Turner
wrote:<br>
</div>
<blockquote
cite="mid:CAAErz9hLRw-kGZtGqcHdWdi1GZrHGrW+crUrvW9CEMZbhLg0=g@mail.gmail.com"
type="cite">
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It would be better, because a debug tablegen is slower than an
optimized tablegen, but it's still slow and it doesn't address the
problem that tablegen runs *at all* when it doesn't really need
to. I think if tablegen wasn't running all the time we could
incremental builds down from 15 minutes (and that's on my really
powerful machine) to under 5, which seemed like a big productivity
boost averaged out over all users x time<br>
<br>
We've got a lot of random stuff in Support, not all really related
and not all relevant to every project. It seems like we should be
able to do better.<br>
</blockquote>
<br>
That certainly makes sense. I wonder, however, if we could have a
more principled decomposition (instead of just "What's used by
TableGen" vs. "What's not used by TableGen").<br>
<br>
-Hal<br>
<br>
<blockquote
cite="mid:CAAErz9hLRw-kGZtGqcHdWdi1GZrHGrW+crUrvW9CEMZbhLg0=g@mail.gmail.com"
type="cite">
<div class="gmail_quote">
<div dir="ltr">On Fri, May 26, 2017 at 6:48 PM Hal Finkel <<a
moz-do-not-send="true" href="mailto:hfinkel@anl.gov">hfinkel@anl.gov</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p><br>
</p>
<div class="m_-6805375126177304137moz-cite-prefix">On
05/26/2017 07:59 PM, Zachary Turner wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">It's that TableGen depends on Support, so
if you change one file in support, support gets
recompiled into a new static archive, which triggers a
rerun of tablegen on all the tablegen inputs, which is
extremely slow.</div>
</blockquote>
<br>
</div>
<div bgcolor="#FFFFFF" text="#000000"> I thought that we had a
"build an optimized tablegen even in debug mode" setting to
work around this problem. Would that avoid this problem?</div>
<div bgcolor="#FFFFFF" text="#000000"><br>
<br>
-Hal</div>
<div bgcolor="#FFFFFF" text="#000000"><br>
<br>
<blockquote type="cite"><br>
<div class="gmail_quote">
<div dir="ltr">On Fri, May 26, 2017 at 5:56 PM Hal
Finkel <<a moz-do-not-send="true"
href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<p><br>
</p>
<br>
<div
class="m_-6805375126177304137m_-895338599256642649moz-cite-prefix">On
05/26/2017 07:47 PM, Zachary Turner via llvm-dev
wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Changing a header file somewhere
and having to spend 10 minutes waiting for a
build leads to a lot of wasted developer time.
<div><br>
</div>
<div>The real culprit here is tablegen. Can we
split support and ADT into two - the parts
that tablegen depends on and the parts that it
doesn't?</div>
</div>
</blockquote>
<br>
</div>
<div bgcolor="#FFFFFF" text="#000000"> What's the
actual problem here? Is it that TableGen regenerates
different files and so we then need to rebuild all
dependencies of those files? Maybe we should use a
diff-and-update approach (I thought, however, that
we already did that).<br>
<br>
-Hal<br>
<br>
</div>
<div bgcolor="#FFFFFF" text="#000000">
<blockquote type="cite">
<div dir="ltr">
<div><br>
</div>
<div>From what I can gather, Tablegen currently
depends on these headers and all of their
transitive dependencies.</div>
<div><br>
</div>
<div>
<div>#include "llvm/Support/Casting.h"</div>
<div>#include "llvm/Support/CommandLine.h"</div>
<div>#include "llvm/Support/Compiler.h"</div>
<div>#include "llvm/Support/DataTypes.h"</div>
<div>#include "llvm/Support/Debug.h"</div>
<div>#include "llvm/Support/Error.h"</div>
<div>#include "llvm/Support/ErrorHandling.h"</div>
<div>#include "llvm/Support/Format.h"</div>
<div>#include "llvm/Support/FormattedStream.h"</div>
<div>#include "llvm/Support/LEB128.h"</div>
<div>#include
"llvm/Support/LowLevelTypeImpl.h"</div>
<div>#include "llvm/Support/ManagedStatic.h"</div>
<div>#include "llvm/Support/MathExtras.h"</div>
<div>#include "llvm/Support/MemoryBuffer.h"</div>
<div>#include
"llvm/Support/PrettyStackTrace.h"</div>
<div>#include "llvm/Support/Regex.h"</div>
<div>#include "llvm/Support/SMLoc.h"</div>
<div>#include "llvm/Support/ScopedPrinter.h"</div>
<div>#include "llvm/Support/Signals.h"</div>
<div>#include "llvm/Support/SourceMgr.h"</div>
<div>#include "llvm/Support/raw_ostream.h"</div>
<div><br>
</div>
<div>#include "llvm/ADT/APInt.h"</div>
<div>#include "llvm/ADT/ArrayRef.h"</div>
<div>#include "llvm/ADT/BitVector.h"</div>
<div>#include "llvm/ADT/CachedHashString.h"</div>
<div>#include "llvm/ADT/DenseSet.h"</div>
<div>#include "llvm/ADT/IndexedMap.h"</div>
<div>#include "llvm/ADT/IntEqClasses.h"</div>
<div>#include "llvm/ADT/MapVector.h"</div>
<div>#include "llvm/ADT/Optional.h"</div>
<div>#include "llvm/ADT/PointerUnion.h"</div>
<div>#include "llvm/ADT/STLExtras.h"</div>
<div>#include "llvm/ADT/SetVector.h"</div>
<div>#include "llvm/ADT/SmallPtrSet.h"</div>
<div>#include "llvm/ADT/SmallSet.h"</div>
<div>#include "llvm/ADT/SmallVector.h"</div>
<div>#include "llvm/ADT/SparseBitVector.h"</div>
<div>#include "llvm/ADT/Statistic.h"</div>
<div>#include "llvm/ADT/StringExtras.h"</div>
<div>#include "llvm/ADT/StringMap.h"</div>
<div>#include "llvm/ADT/StringRef.h"</div>
<div>#include "llvm/ADT/StringSet.h"</div>
<div>#include "llvm/ADT/StringSwitch.h"</div>
<div>#include "llvm/ADT/TinyPtrVector.h"</div>
<div>#include "llvm/ADT/Twine.h"</div>
</div>
<div><br>
</div>
<div>
<div><br
class="m_-6805375126177304137m_-895338599256642649inbox-inbox-Apple-interchange-newline">
Is this something worth putting effort
into? If so, I volunteer.</div>
<br
class="m_-6805375126177304137m_-895338599256642649inbox-inbox-Apple-interchange-newline">
</div>
</div>
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<blockquote type="cite">
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<div bgcolor="#FFFFFF" text="#000000"> <br>
<pre class="m_-6805375126177304137m_-895338599256642649moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre>
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</blockquote>
<br>
<pre class="m_-6805375126177304137moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre>
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</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre>
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