When building in Debug on Windows-MSVC after b7402edce3, a lot of tests were failing because we were dereferencing an element past the end of HashRecords. This happened towards the end of the table, in unused slots.
This reduces peak memory on my test case from 1960.14MB to 1700.63MB
(-260MB, -13.2%) with no measurable impact on CPU time. I'm currently
working with a publics stream that is about 277MB. Before this change,
we would allocate 277MB of heap memory, serialize publics into them,
hold onto that heap memory, open the PDB, and commit into it. After
this change, we defer the serialization until commit time.
In the last change I made to public writing, I re-sorted the list of
publics multiple times in place to avoid allocating new temporary data
structures. Deferring serialization until later requires that we don't
reorder the publics. Instead of sorting the publics, I partially
construct the hash table data structures, store a publics index in them,
and then sort the hash table data structures. Later, I replace the index
with the symbol record offset.
This change also addresses a FIXME and moves the list of global and
public records from GSIHashStreamBuilder to GSIStreamBuilder. Now that
publics aren't being serialized, it makes even less sense to store them
as a list of CVSymbol records. The hash table used to deduplicate
globals is moved as well, since that is specific to globals, and not
publics.
Reviewed By: aganea, hans
Differential Revision: https://reviews.llvm.org/D81296
Reduces time to link PGO instrumented net_unittets.exe by 11% (9.766s ->
8.672s, best of three). Reduces peak memory by 65.7MB (2142.71MB ->
2076.95MB).
Use a more compact struct, BulkPublic, for faster sorting. Sort in
parallel. Construct the hash buckets in parallel. Try to use one vector
to hold all the publics instead of copying them from one to another.
Allocate all the memory needed to serialize publics up front, and then
serialize them in place in parallel.
Reviewed By: aganea, hans
Differential Revision: https://reviews.llvm.org/D79467
The number of public symbols is very large, and each deserialization
does a few heap allocations. The public symbols are serialized by the
linker, so we can assume they have the expected layout and use it
directly.
Saves O(#publics) temporary heap allocations and shrinks some data
structures.
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
llvm-svn: 369013
Summary: Deduplicate S_CONSTANTS when linking, if they have the same value.
Reviewers: rnk
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63151
llvm-svn: 363089
Summary:
Now CVType and CVSymbol are effectively type-safe wrappers around
ArrayRef<uint8_t>. Make the kind() accessor load it from the
RecordPrefix, which is the same for types and symbols.
Reviewers: zturner, aganea
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60018
llvm-svn: 357658
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Previously these were dropped. We now understand them sufficiently
well to start emitting them. From the debugger's perspective, this
now enables us to have debug info about typedefs (both global and
function-locally scoped)
Differential Revision: https://reviews.llvm.org/D55228
llvm-svn: 348306
Makes the produced pdbs more deterministic; before they'd contain 2 arbitary
bytes where this padding was.
Also reorder initialization to match the order of the fields in the struct (nfc)
llvm-svn: 341945
The reference implementation uses a case-insensitive string
comparison for strings of equal length. This will cause the
string "tEo" to compare less than "VUo". However we were using
a case sensitive comparison, which would generate the opposite
outcome. Switch to a case insensitive comparison. Also, when
one of the strings contains non-ascii characters, fallback to
a straight memcmp.
The only way to really test this is with a DIA test. Before this
patch, the test will fail (but succeed if link.exe is used instead
of lld-link). After the patch, it succeeds even with lld-link.
llvm-svn: 336464
It seems like the debugger first computes a symbol's bucket,
and then does a binary search of entries in the bucket using the
symbol's name in order to find it. If the bucket entries are not
in sorted order, this obviously won't work. After this patch a
couple of simple test cases show that we generate an exactly
identical GSI hash stream, which is very nice.
llvm-svn: 336405
When investigating bugs in PDB generation, the first step is
often to do the same link with link.exe and then compare PDBs.
But comparing PDBs is hard because two completely different byte
sequences can both be correct, so it hampers the investigation when
you also have to spend time figuring out not just which bytes are
different, but also if the difference is meaningful.
This patch fixes a couple of cases related to string table emission,
hash table emission, and the order in which we emit strings that
makes more of our bytes the same as the bytes generated by MS PDBs.
Differential Revision: https://reviews.llvm.org/D44810
llvm-svn: 328348
computeAddrMap function calls std::stable_sort with a comparison
function that computes deserialized symbols every time its called.
In the result deserializeAs<PublicSym32> is called 20-30 times per
symbol. It's much faster to calculate it beforehand and pass a
pointer to it to the comparison function.
Patch by Alex Telishev
Differential Revision: https://reviews.llvm.org/D36941
llvm-svn: 311373
Previously we were writing an empty globals stream. Windows
tools interpret this as "private symbols are not present in
this PDB", even when they are, so we need to fix this. Regardless,
without it we don't have information about global variables, so
we need to fix it anyway. This patch does that.
With this patch, the "lm" command in WinDbg correctly reports
that we have private symbols available, but the "dv" command
still refuses to display local variables.
Differential Revision: https://reviews.llvm.org/D36535
llvm-svn: 310743
In the refactor to merge the publics and globals stream, a bug
was introduced that wrote the wrong value for one of the fields
of the PublicsStreamHeader. This caused debugging in WinDbg
to break.
We had no way of dumping any of these fields, so in addition to
fixing the bug I've added dumping support for them along with a
test that verifies the correct value is written.
llvm-svn: 310439
The publics stream and globals stream are very similar. They both
contain a list of hash buckets that refer into a single shared stream,
the symbol record stream. Because of the need for each builder to manage
both an independent hash stream as well as a single shared record
stream, making the two builders be independent entities is not the right
design. This patch merges them into a single class, of which only a
single instance is needed to create all 3 streams. PublicsStreamBuilder
and GlobalsStreamBuilder are now merged into the single GSIStreamBuilder
class, which writes all 3 streams at once.
Note that this patch does not contain any functionality change. So we're
still not yet writing any records to the globals stream. All we're doing
is making it so that when we do start writing records to the globals,
this refactor won't have to be part of that patch.
Differential Revision: https://reviews.llvm.org/D36489
llvm-svn: 310438
Nico Weber