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    <div class="moz-cite-prefix">On 05/26/2017 07:59 PM, Zachary Turner
      wrote:<br>
    </div>
    <blockquote
cite="mid:CAAErz9jH2VGdkgantDnssUbgngPTY2mmjokKTRTDaTkx5UA66g@mail.gmail.com"
      type="cite">
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      <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>
    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?<br>
    <br>
     -Hal<br>
    <br>
    <blockquote
cite="mid:CAAErz9jH2VGdkgantDnssUbgngPTY2mmjokKTRTDaTkx5UA66g@mail.gmail.com"
      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">hfinkel@anl.gov</a>>
          wrote:<br>
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          .8ex;border-left:1px #ccc solid;padding-left:1ex">
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            <p><br>
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            <br>
            <div class="m_-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>
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                <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_-895338599256642649inbox-inbox-Apple-interchange-newline">
                    Is this something worth putting effort into?  If so,
                    I volunteer.</div>
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                    class="m_-895338599256642649inbox-inbox-Apple-interchange-newline">
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            <blockquote type="cite">
              <pre>_______________________________________________
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</pre>
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          <div bgcolor="#FFFFFF" text="#000000"> <br>
            <pre class="m_-895338599256642649moz-signature" cols="72">-- 
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre>
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    <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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