When parsing a C++17 binding declaration, we first create the
BindingDecls in Sema::ActOnDecompositionDeclarator, and then build the
DecompositionDecl in Sema::ActOnVariableDeclarator, so the contained
BindingDecls are never null. But when deserializing, we read the
DecompositionDecl with all properties before filling in the Bindings.
Among other things, reading a declaration reads whether it's invalid,
then calling setInvalidDecl which assumes that all bindings of the
DecompositionDecl are available, but that isn't the case.
Deserialization should just set all properties directly without invoking
subsequent functions, so we just set the flag without using the setter.
Fixes PR34960.
Reviewed By: rsmith
Differential Revision: https://reviews.llvm.org/D86207
Add -fpch-instantiate-templates which makes template instantiations be
performed already in the PCH instead of it being done in every single
file that uses the PCH (but every single file will still do it as well
in order to handle its own instantiations). I can see 20-30% build
time saved with the few tests I've tried.
The change may reorder compiler output and also generated code, but
should be generally safe and produce functionally identical code.
There are some rare cases that do not compile with it,
such as test/PCH/pch-instantiate-templates-forward-decl.cpp. If
template instantiation bailed out instead of reporting the error,
these instantiations could even be postponed, which would make them
work.
Enable this by default for clang-cl. MSVC creates PCHs by compiling
them using an empty .cpp file, which means templates are instantiated
while building the PCH and so the .h needs to be self-contained,
making test/PCH/pch-instantiate-templates-forward-decl.cpp to fail
with MSVC anyway. So the option being enabled for clang-cl matches this.
Differential Revision: https://reviews.llvm.org/D69585
Aaron Puchert