[PATCH] D27545: Don't assert when redefining a built-in macro in a PCH, PR29119

[Richard Smith via Phabricator via cfe-commits]

rsmith added inline comments.


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Comment at: lib/Lex/PPMacroExpansion.cpp:110-112
+    // FIXME: shouldIgnoreMacro() in ASTWriter also stops at macros from the
+    // predefines buffer in module builds. Do we need to splice to those here
+    // too?
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If I remember correctly, we shouldn't need to; we run this step before we start lexing the predefines buffer. However, that does mean that macros on the command line will *override* macros from the PCH, which seems like it's probably the wrong behavior...


https://reviews.llvm.org/D27545