Pass /bigobj when building lib/ASTMatchers/Dynamic/Registry.cpp

This is the third time it has crossed the 2^16 section limit. We've
already spent time optimizing this file to reduce template
instantiations, and it's not clear that there is anymore low hanging
fruit.

llvm-svn: 260267

clang/lib/ASTMatchers/Dynamic/CMakeLists.txt

@@ -1,5 +1,14 @@
 set(LLVM_LINK_COMPONENTS support)
 
+# The registry source file ends up generating a lot of sections for each
+# matcher. Each matcher appears to get a vtable and several methods. Each
+# method needs .text, .pdata, .xdata, and .debug sections, adding to the
+# section multiplier. By default MSVC has a 2^16 limit on the number of
+# sections in an object file, and this needs more than that.
+if (MSVC)
+  set_source_files_properties(Registry.cpp PROPERTIES COMPILE_FLAGS /bigobj)
+endif()
+
 add_clang_library(clangDynamicASTMatchers
   Diagnostics.cpp
   VariantValue.cpp