Summary:
This patch adds support for ULEB128 and SLEB128 encoding and decoding to
BinaryStreamWriter and BinaryStreamReader respectively.
Support for ULEB128/SLEB128 will be used for eh-frame parsing in the JITLink
library currently under development (see https://reviews.llvm.org/D58704).
Reviewers: zturner, dblaikie
Subscribers: kristina, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60810
llvm-svn: 358584
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
This is essentially just a BinaryStreamRef packaged with an
offset and the logic for reading one is no different than the
logic for reading a BinaryStreamRef, except that we save the
current offset.
llvm-svn: 306122
Previously it would do a character by character search for a null
terminator, to account for the fact that an arbitrary stream need not
store its data contiguously so you couldn't just do a memchr. However, the
stream API has a function which will return the longest contiguous chunk
without doing a copy, and by using this function we can do a memchr on the
individual chunks. For certain types of streams like data from object
files etc, this is guaranteed to find the null terminator with only a
single memchr, but even with discontiguous streams such as
MappedBlockStream, it's rare that any given string will cross a block
boundary, so even those will almost always be satisfied with a single
memchr.
This optimization is worth a 10-12% reduction in link time (4.2 seconds ->
3.75 seconds)
Differential Revision: https://reviews.llvm.org/D33503
llvm-svn: 303918
Often you have an array and you just want to use it. With the current
design, you have to first construct a `BinaryByteStream`, and then create
a `BinaryStreamRef` from it. Worse, the `BinaryStreamRef` holds a pointer
to the `BinaryByteStream`, so you can't just create a temporary one to
appease the compiler, you have to actually hold onto both the `ArrayRef`
as well as the `BinaryByteStream` *AND* the `BinaryStreamReader` on top of
that. This makes for very cumbersome code, often requiring one to store a
`BinaryByteStream` in a class just to circumvent this.
At the cost of some added complexity (not exposed to users, but internal
to the library), we can do better than this. This patch allows us to
construct `BinaryStreamReaders` and `BinaryStreamWriters` directly from
source data (e.g. `StringRef`, `MutableArrayRef<uint8_t>`, etc). Not only
does this reduce the amount of code you have to type and make it more
obvious how to use it, but it solves real lifetime issues when it's
inconvenient to hold onto a `BinaryByteStream` for a long time.
The additional complexity is in the form of an added layer of indirection.
Whereas before we simply stored a `BinaryStream*` in the ref, we now store
both a `BinaryStream*` **and** a `std::shared_ptr<BinaryStream>`. When
the user wants to construct a `BinaryStreamRef` directly from an
`ArrayRef` etc, we allocate an internal object that holds ownership over a
`BinaryByteStream` and forwards all calls, and store this in the
`shared_ptr<>`. This also maintains the ref semantics, as you can copy it
by value and references refer to the same underlying stream -- the one
being held in the object stored in the `shared_ptr`.
Differential Revision: https://reviews.llvm.org/D33293
llvm-svn: 303294
This was reverted due to a "missing" file, but in reality
what happened was that I renamed a file, and then due to
a merge conflict both the old file and the new file got
added to the repository. This led to an unused cpp file
being in the repo and not referenced by any CMakeLists.txt
but #including a .h file that wasn't in the repo. In an
even more unfortunate coincidence, CMake didn't report the
unused cpp file because it was in a subdirectory of the
folder with the CMakeLists.txt, and not in the same directory
as any CMakeLists.txt.
The presence of the unused file was then breaking certain
tools that determine file lists by globbing rather than
by what's specified in CMakeLists.txt
In any case, the fix is to just remove the unused file from
the patch set.
llvm-svn: 302042
The patch is failing to add StringTableStreamBuilder.h, but that isn't
even discovered because the corresponding StringTableStreamBuilder.cpp
isn't added to any CMakeLists.txt file and thus never built. I think
this patch is just incomplete.
llvm-svn: 302002
Previously we had knowledge of how to serialize and deserialize
a string table inside of DebugInfo/PDB, but the string table
that it serializes contains a piece that is actually considered
CodeView and can appear outside of a PDB. We already have logic
in llvm-readobj and MCCodeView to read and write this format,
so it doesn't make sense to duplicate the logic in DebugInfoPDB
as well.
This patch makes codeview::StringTable (for writing) and
codeview::StringTableRef (for reading), updates DebugInfoPDB
to use these classes for its own writing, and updates llvm-readobj
to additionally use StringTableRef for reading.
It's a bit more difficult to get MCCodeView to use this for
writing, but it's a logical next step.
llvm-svn: 301986
After several smaller patches to get most of the core improvements
finished up, this patch is a straight move and header fixup of
the source.
Differential Revision: https://reviews.llvm.org/D30266
llvm-svn: 296810
Simon Pilgrim