We have some code to try to determine how many pieces an MSF
Free Page Map is split into, and this code had an off by one
error which would cause the calculation to be incorrect when
there were exactly 4096*k + 1 blocks in an MSF file.
Original investigation and patch outline by Colden Cullen.
Differential Revision: https://reviews.llvm.org/D41742
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321880 91177308-0d34-0410-b5e6-96231b3b80d8
inlined subroutines for a given address.
This is essentially the hot path of llvm-symbolizer when extracting
inlined frames during symbolization. Previously, we would read every
subprogram and every inlined subroutine, building a std::map across the
entire PC space to the best DIE, and then do only a handful of queries
as we symbolized a backtrace. A huge fraction of the time was spent
building the map itself.
This patch changes it two a two-level system. First, we just build a map
from PC-interval to DWARF subprograms. These are required to be disjoint
and so constructing this is pretty easy. Second, we build a map *just*
for the inlined subroutines within the subprogram containing the query
address. This allows us to look at far fewer DIEs and build a *much*
smaller set of cached maps in the llvm-symbolizer case where only a few
address get symbolized during the entire run.
It also builds both interval maps in a very different way. It constructs
a single flat vector of pairs that maps from offset -> index. The
indices point into collections of DIE objects, but can also be
"tombstones" (-1) to mark gaps. In the case of subprograms, this mostly
just simplifies the data structure a bit. For inlined subroutines,
because we carefully split them as we build the map, we end up in many
cases having no holes and not having to store both start and stop
offsets.
Finally, the PC ranges for the inlined subroutines are compressed into
32-bits by making them relative to the base PC of the outer subprogram.
This means that if you have a single function body with over 2gb of
executable code in it, we will stop mapping address past the first 2gb
of that function into inlined subroutines and just give you the
subprogram. This doesn't seem like a problem. ;]
All of this combines to make llvm-symbolizer *well* over 2x faster for
symbolizing backtraces out of LLVM's unittests. Death-test heavy unit
tests are running >2x faster. I'm still going to look at completely
disabling symbolization there, but figured while I had a good benchmark
we should make symbolization a bit better.
Sadly, the logic to build the flat interval map for the inlined
subroutines is fairly complex. I'm not super happy about this and
welcome any simplifying suggestions.
Huge thanks to Dave Blaikie who helped walk me through what the various
things I needed to do in DWARF to make this work.
Differential Revision: https://reviews.llvm.org/D40987
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321345 91177308-0d34-0410-b5e6-96231b3b80d8
Reorganizes the DWARF consumer to derive the string offsets table
contribution's format from the contribution header instead of
(incorrectly) from the unit's format.
Reviewers: JDevliegehere, aprantl
Differential Revision: https://reviews.llvm.org/D41146
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321295 91177308-0d34-0410-b5e6-96231b3b80d8
This adds the /DEBUG:GHASH option to LLD which will look for
the existence of .debug$H sections in linker inputs and use them
to accelerate type merging. The clang-cl side has already been
added, so this completes the work necessary to begin experimenting
with this feature.
Differential Revision: https://reviews.llvm.org/D40980
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320719 91177308-0d34-0410-b5e6-96231b3b80d8
Currently this is an LLVM extension to the COFF spec which is
experimental and intended to speed up linking. For now it is
behind a hidden cl::opt flag, but in the future we can move it
to a "real" cc1 flag and have the driver pass it through whenever
it is appropriate.
The patch to actually make use of this section in lld will come
in a followup.
Differential Revision: https://reviews.llvm.org/D40917
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320649 91177308-0d34-0410-b5e6-96231b3b80d8
This fixes a bug where the verifier was complaining about empty
accelerator tables. When the table is empty, its size is not a valid
offset as it points after the end of the section.
This patch also makes the extractor return llvm:Error instead of bool
for better error reporting in the verifier.
Differential revision: https://reviews.llvm.org/D41063
rdar://35932007
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320399 91177308-0d34-0410-b5e6-96231b3b80d8
--diff Emit the output in a diff-friendly way by omitting offsets and
addresses.
<rdar://problem/34502625>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320214 91177308-0d34-0410-b5e6-96231b3b80d8
Previously, when linking against libcmt from the MSVC runtime,
lld-link /verbose would show "Ignoring unknown symbol record
with kind 0x1006". It turns out this was because
TypeIndexDiscovery did not handle S_REGISTER records, so these
records were not getting properly remapped.
Patch by: Alexnadre Ganea
Differential Revision: https://reviews.llvm.org/D40919
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@320108 91177308-0d34-0410-b5e6-96231b3b80d8
This was storing the hash alongside the key so that the hash
doesn't need to be re-computed every time, but in doing so it
was allocating a structure to keep the key size small in the
DenseMap. This is a noble goal, but it also leads to a pointer
indirection on every probe, and this cost of this pointer
indirection ends up being higher than the cost of having a
slightly larger entry in the hash table. Removing this not only
simplifies the code, but yields a small but noticeable
performance improvement in the type merging algorithm.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319493 91177308-0d34-0410-b5e6-96231b3b80d8
This class had some code that would automatically remap type
indices before hashing and serializing. The only caller of
this method was the TypeStreamMerger anyway, and the method
doesn't make general sense, and prevents making certain future
improvements to the class. So, factoring this up one level
into the TypeStreamMerger where it belongs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319377 91177308-0d34-0410-b5e6-96231b3b80d8
A couple of places in LLD were passing references to
TypeTableCollections around, which makes it hard to change the
implementation at runtime. However, these cases only needed to
iterate over the types in the collection, and TypeCollection
already provides a handy abstract interface for this purpose.
By implementing this interface, we can get rid of the need to
pass TypeTableBuilder references around, which should allow us
to swap the implementation at runtime in subsequent patches.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319345 91177308-0d34-0410-b5e6-96231b3b80d8
The motivation behind this patch is that future directions require us to
be able to compute the hash value of records independently of actually
using them for de-duplication.
The current structure of TypeSerializer / TypeTableBuilder being a
single entry point that takes an unserialized type record, and then
hashes and de-duplicates it is not flexible enough to allow this.
At the same time, the existing TypeSerializer is already extremely
complex for this very reason -- it tries to be too many things. In
addition to serializing, hashing, and de-duplicating, ti also supports
splitting up field list records and adding continuations. All of this
functionality crammed into this one class makes it very complicated to
work with and hard to maintain.
To solve all of these problems, I've re-written everything from scratch
and split the functionality into separate pieces that can easily be
reused. The end result is that one class TypeSerializer is turned into 3
new classes SimpleTypeSerializer, ContinuationRecordBuilder, and
TypeTableBuilder, each of which in isolation is simple and
straightforward.
A quick summary of these new classes and their responsibilities are:
- SimpleTypeSerializer : Turns a non-FieldList leaf type into a series of
bytes. Does not do any hashing. Every time you call it, it will
re-serialize and return bytes again. The same instance can be re-used
over and over to avoid re-allocations, and in exchange for this
optimization the bytes returned by the serializer only live until the
caller attempts to serialize a new record.
- ContinuationRecordBuilder : Turns a FieldList-like record into a series
of fragments. Does not do any hashing. Like SimpleTypeSerializer,
returns references to privately owned bytes, so the storage is
invalidated as soon as the caller tries to re-use the instance. Works
equally well for LF_FIELDLIST as it does for LF_METHODLIST, solving a
long-standing theoretical limitation of the previous implementation.
- TypeTableBuilder : Accepts sequences of bytes that the user has already
serialized, and inserts them by de-duplicating with a hash table. For
the sake of convenience and efficiency, this class internally stores a
SimpleTypeSerializer so that it can accept unserialized records. The
same is not true of ContinuationRecordBuilder. The user is required to
create their own instance of ContinuationRecordBuilder.
Differential Revision: https://reviews.llvm.org/D40518
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319198 91177308-0d34-0410-b5e6-96231b3b80d8
The previous implementation would only look 1 DW_AT_specification or DW_AT_abstract_origin deep. This means DWARFDie::getName() would fail in certain cases. I ran into such a case while creating a tool that used the LLVM DWARF parser to generate a symbolication format so I have seen this in the wild.
Differential Revision: https://reviews.llvm.org/D40156
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319104 91177308-0d34-0410-b5e6-96231b3b80d8
The existing library assumed that a stream's length would never
change. This makes some things simpler, but it's not flexible
enough for what we need, especially for writable streams where
what you really want is for each call to write to actually append.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319070 91177308-0d34-0410-b5e6-96231b3b80d8
DWARF4 relative DW_AT_high_pc values are now displayed as absolute
addresses. The relative value is only shown when explicitly dumping the
forms, i.e. in show-form or verbose mode.
```
DW_AT_low_pc (0x0000000000000049)
DW_AT_high_pc (0x00000019)
```
becomes
```
DW_AT_low_pc (0x0000000000000049)
DW_AT_high_pc (0x0000000000000062)
```
Differential revision: https://reviews.llvm.org/D40317
rdar://35416943
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319044 91177308-0d34-0410-b5e6-96231b3b80d8
As a side effect, the .debug_line section will be dumped in physical
order, rather than in the order that compile units refer to their
associated portions of the .debug_line section. These are probably
always the same order anyway, and no tests noticed the difference.
Differential Revision: https://reviews.llvm.org/D39854
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318839 91177308-0d34-0410-b5e6-96231b3b80d8
It turns out this #include isn't used from Host.h anyway,
but by having it it causes circular include dependencies.
This issues only surfaced while I was working on a separate
patch, so I'm submitting this first so that it's independent
of the other, unrelated patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318489 91177308-0d34-0410-b5e6-96231b3b80d8
Initial changes to support debugging PE/COFF files with LLDB on Windows through DIA SDK.
There is another set of changes required on the LLDB side before this does anything.
Differential Revision: https://reviews.llvm.org/D39517
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318403 91177308-0d34-0410-b5e6-96231b3b80d8
Patch improves next things:
* Fixes assert/crash in getOpDesc when giving it a invalid expression op code.
* DWARFExpression::print() called DWARFExpression::Operation::getEndOffset() which
returned and used uninitialized field EndOffset. Patch fixes that.
* Teaches verifier to verify DW_AT_location and error out on broken expressions.
Differential revision: https://reviews.llvm.org/D39294
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316756 91177308-0d34-0410-b5e6-96231b3b80d8
Adrian Prantl