See the added test for the motivation example. In that example, we add a
new function declaration in `a.cppm` and this is not used in the reduced
BMI of `b.cppm`. We expect that the change won't affect the BMI of
`b.cppm`. But it is the not the case.
There are 2 reason for unexpected result:
1. We would register the interesting identifiers in a pretty late phase.
This may cause some some predefined identifier ID change due to we
insert other identifiers during emitting decls and types.
2. In `GenerateNameLookup`, we would generate information for predefined
decls. This may not be intended. Since every predefined decl doesn't
belong to any module.
And this patch solves the first issue by registering the identifiers in
the very early posititon to make sure the ID won't get affected by the
process to emit decls and types. And we solve the second question by
filtering predefined decls simply.
This patch tries to reduce the size of the BMIs by packing more bits
into an unsigned integer.
This patch was reverted due to buildbot failure report. But it should be
irrevelent after I took a double look. So I tried to recommit this NFC
change again.
Fix decl-params-determinisim test after 48be81e1 packed some information
in the clang module. The test is to make sure the decls are appearing in
a strict ordering and it relies on check the correct field in the
bitcode format.
Add more explanation in the comments to help future updates when
serialization format affects this test.
Previously, the boolean values will occupy spaces that can contain
integers. It wastes the spaces especially if the boolean values are
serialized consecutively. The patch tries to pack such consecutive
boolean values (and enum values) so that we can save more spaces and so
the times.
Before the patch, we need 4.478s (in my machine) to build the std module
(https://libcxx.llvm.org/Modules.html) with 28712 bytes for size of the
BMI. After the patch, the time becomes to 4.374s and the size becomes to
27388 bytes for the size of the BMI.
This is intended to be a NFC patch.
This patch doesn't optimize all such cases. We can do it later after we
have consensus on this.
Fix a non-deterministic issue in clang module generation, which the
anonymous declaration number from a function context is not
deterministic. This is due to the unstable iteration order for decls in
scope so the order after moving the decls into function decl context is
not deterministic.
From https://reviews.llvm.org/D135118, we can't use a set that preserves
the order without the performance penalty. Fix the issue by sorting the
decls based on raw encoding of their source location.
rdar://104097976
Reviewed By: akyrtzi, vsapsai
Differential Revision: https://reviews.llvm.org/D141625
