This paves the way to making OnDiskHashTable work with hashes that are
not 32 bits wide and to making OnDiskHashTable work very large hash
tables. The LLVM change to use these types is upcoming.
llvm-svn: 206640
To differentiate between two modules with the same name, we will
consider the path the module map file that they are defined by* part of
the ‘key’ for looking up the precompiled module (pcm file).
Specifically, this patch renames the precompiled module (pcm) files from
cache-path/<module hash>/Foo.pcm
to
cache-path/<module hash>/Foo-<hash of module map path>.pcm
In addition, I’ve taught the ASTReader to re-resolve the names of
imported modules during module loading so that if the header search
context changes between when a module was originally built and when it
is loaded we can rebuild it if necessary. For example, if module A
imports module B
first time:
clang -I /path/to/A -I /path/to/B ...
second time:
clang -I /path/to/A -I /different/path/to/B ...
will now rebuild A as expected.
* in the case of inferred modules, we use the module map file that
allowed the inference, not the __inferred_module.map file, since the
inferred file path is the same for every inferred module.
llvm-svn: 206201
Currently the on disk hash table's key_iterator and data_iterator make
the assumption that the table data starts exactly four bytes after the
base of the table. This happens to be true for all of the tables we
currently iterate over, but not for all of the OnDiskHashTables we
currently use. For example, key_ and data_iterator would iterate over
meaningless data if they were used on the hash tables in PTHLexer.
We make the API safer by breaking this into two types. One doesn't
have the iterators, and the other must be told where the payload
starts.
llvm-svn: 206189
Committed this by accident before it was done last time.
Original message:
Rather than rolling our own functions to read little endian data
from a buffer, we can use the support in llvm's Endian.h.
No functional change.
llvm-svn: 205062
Committed this by accident before it was done last time.
Original message:
Rather than rolling our own functions to write little endian data
to an ostream, we can use the support in llvm's EndianStream.h.
No functional change.
llvm-svn: 205061
Rather than rolling our own functions to read little endian data from
a buffer, we can use the support in llvm's Endian.h.
No functional change.
llvm-svn: 205045
Rather than rolling our own functions to write little endian data to
an ostream, we can use the support in llvm's EndianStream.h.
No functional change.
llvm-svn: 205044
Typo correction for an unqualified name needs to walk through all of the identifier tables of all modules.
When we have a global index, just walk its identifier table only.
rdar://13425732
llvm-svn: 179730
The refactoring in r177367 introduced a serious performance bug where
the "lazy" resolution of module file names in the global module index
to actual module file entries in the module manager would perform
repeated negative stats(). The new interaction requires the module
manager to inform the global module index when a module file has been
loaded, eliminating the extraneous stat()s and a bunch of bookkeeping
on both sides.
llvm-svn: 177750
The global module index was querying the file manager for each of the
module files it knows about at load time, to prune out any out-of-date
information. The file manager would then cache the results of the
stat() falls used to find that module file.
Later, the same translation unit could end up trying to import one of the
module files that had previously been ignored by the module cache, but
after some other Clang instance rebuilt the module file to bring it
up-to-date. The stale stat() results in the file manager would
trigger a second rebuild of the already-up-to-date module, causing
failures down the line.
The global module index now lazily resolves its module file references
to actual AST reader module files only after the module file has been
loaded, eliminating the stat-caching race. Moreover, the AST reader
can communicate to its caller that a module file is missing (rather
than simply being out-of-date), allowing us to simplify the
module-loading logic and allowing the compiler to recover if a
dependent module file ends up getting deleted.
llvm-svn: 177367
Essentially, a module file on disk could change size between the time
we stat() it and the time we open it, and we need to be robust against
such a problem.
llvm-svn: 174529
index, optimizing the operation that skips lookup in modules where we
know the identifier will not be found. This makes the global module
index optimization actually useful, providing an 8.5% speedup over
modules without the global module index for -fsyntax-only.
llvm-svn: 173529
AST reader.
The global module index tracks all of the identifiers known to a set
of module files. Lookup of those identifiers looks first in the global
module index, which returns the set of module files in which that
identifier can be found. The AST reader only needs to look into those
module files and any module files not known to the global index (e.g.,
because they were (re)built after the global index), reducing the
number of on-disk hash tables to visit. For an example source I'm
looking at, we go from 237844 total identifier lookups into on-disk
hash tables down to 126817.
Unfortunately, this does not translate into a performance advantage.
At best, it's a wash once the global module index has been built, but
that's ignore the cost of building the global module index (which
is itself fairly large). Profiles show that the global module index
code is far less efficient than it should be; optimizing it might give
enough of an advantage to justify its continued inclusion.
llvm-svn: 173405
The global module index is a "global" index for all of the module
files within a particular subdirectory in the module cache, which
keeps track of all of the "interesting" identifiers and selectors
known in each of the module files. One can perform a fast lookup in
the index to determine which module files will have more information
about entities with a particular name/selector. This information can
help eliminate redundant lookups into module files (a serious
performance problem) and help with creating auto-import/auto-include
Fix-Its.
The global module index is created or updated at the end of a
translation unit that has triggered a (re)build of a module by
scraping all of the .pcm files out of the module cache subdirectory,
so it catches everything. As with module rebuilds, we use the file
system's atomicity to synchronize.
llvm-svn: 173301
Rafael Espindola