[PATCH] D45899: TableGen: Add a --write-if-changed flag to tablegen directly instead of doing it in cmake.

[Reid Kleckner via Phabricator via llvm-commits]

rnk accepted this revision.
rnk added inline comments.
This revision is now accepted and ready to land.


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Comment at: lib/TableGen/Main.cpp:110-112
+  auto MBOrErr = MemoryBuffer::getFile(OutputFilename);
+  bool OutputChanged =
+      MBOrErr.getError() || std::move(MBOrErr.get())->getBuffer() != Out.str();
----------------
A variable name like `ExistingOrError` might be better here, and we could probably write it like:
  bool OutputChanged = true;
  if (auto ExistingOrErr = MemoryBuffer::getFile(OutputFilename))
    OutputChanged = std::move(ExistingOrErr)->getBuffer() != Out.str();


================
Comment at: lib/TableGen/Main.cpp:113
+      MBOrErr.getError() || std::move(MBOrErr.get())->getBuffer() != Out.str();
+  if (!OutputChanged && WriteIfChanged)
+    return 0;
----------------
thakis wrote:
> Not sure if we should even have a --write-if-changed flag instead of doing this unconditionally, since we always pass the flag.
I'm in favor of removing the option and doing this unconditionally.


https://reviews.llvm.org/D45899