Commit Graph

4 Commits

Author SHA1 Message Date
Luboš Luňák a45f713c67 add option to instantiate templates already in the PCH
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
2020-06-21 17:05:52 +02:00
Richard Smith 151c456858 [c++1z] P0195R2: Support pack-expansion of using-declarations.
This change introduces UsingPackDecl as a marker for the set of UsingDecls
produced by pack expansion of a single (unresolved) using declaration. This is
not strictly necessary (we just need to be able to map from the original using
declaration to its expansions somehow), but it's useful to maintain the
invariant that each declaration reference instantiates to refer to one
declaration.

This is a re-commit of r290080 (reverted in r290092) with a fix for a
use-after-lifetime bug.

llvm-svn: 290203
2016-12-20 21:35:28 +00:00
Daniel Jasper 9949ead55a Revert "[c++1z] P0195R2: Support pack-expansion of using-declarations."
This reverts commit r290080 as it leads to many Clang crashes, e.g.:
http://lab.llvm.org:8011/builders/clang-cmake-aarch64-quick/builds/1814

llvm-svn: 290092
2016-12-19 10:09:25 +00:00
Richard Smith 22a250cd5d [c++1z] P0195R2: Support pack-expansion of using-declarations.
This change introduces UsingPackDecl as a marker for the set of UsingDecls
produced by pack expansion of a single (unresolved) using declaration. This is
not strictly necessary (we just need to be able to map from the original using
declaration to its expansions somehow), but it's useful to maintain the
invariant that each declaration reference instantiates to refer to one
declaration.

llvm-svn: 290080
2016-12-19 04:08:53 +00:00