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
There was some code that tried to calculate the number of 4-byte
words required to hold N bits, but it was instead computing the
number of bytes required to hold N bits. This was leading to
extraneous data being output into the hash table, which would
cause certain operations in DIA (the Microsoft PDB reader) to
fail.
llvm-svn: 327675
It previously only worked when the key and value types were
both 4 byte integers. We now have a use case for a non trivial
value type, so we need to extend it to support arbitrary value
types, which means templatizing it.
llvm-svn: 327647
This was originally reported as a bug with the symptom being "cvdump
crashes when printing an LLD-linked PDB that has an S_FILESTATIC record
in it". After some additional investigation, I determined that this was
a symptom of a larger problem, and in fact the real problem was in the
way we emitted the global PDB string table. As evidence of this, you can
take any lld-generated PDB, run cvdump -stringtable on it, and it would
return no results.
My hypothesis was that cvdump could not *find* the string table to begin
with. Normally it would do this by looking in the "named stream map",
finding the string /names, and using its value as the stream index. If
this lookup fails, then cvdump would fail to load the string table.
To test this hypothesis, I looked at the name stream map generated by a
link.exe PDB, and I emitted exactly those bytes into an LLD-generated
PDB. Suddenly, cvdump could read our string table!
This code has always been hacky and we knew there was something we
didn't understand. After all, there were some comments to the effect of
"we have to emit strings in a specific order, otherwise things don't
work". The key to fixing this was finally understanding this.
The way it works is that it makes use of a generic serializable hash map
that maps integers to other integers. In this case, the "key" is the
offset into a buffer, and the value is the stream number. If you index
into the buffer at the offset specified by a given key, you find the
name. The underlying cause of all these problems is that we were using
the identity function for the hash. i.e. if a string's offset in the
buffer was 12, the hash value was 12. Instead, we need to hash the
string *at that offset*. There is an additional catch, in that we have
to compute the hash as a uint32 and then truncate it to uint16.
Making this work is a little bit annoying, because we use the same hash
table in other places as well, and normally just using the identity
function for the hash function is actually what's desired. I'm not
totally happy with the template goo I came up with, but it works in any
case.
The reason we never found this bug through our own testing is because we
were building a /parallel/ hash table (in the form of an
llvm::StringMap<>) and doing all of our lookups and "real" hash table
work against that. I deleted all of that code and now everything goes
through the real hash table. Then, to test it, I added a unit test which
adds 7 strings and queries the associated values. I test every possible
insertion order permutation of these 7 strings, to verify that it really
does work as expected.
Differential Revision: https://reviews.llvm.org/D43326
llvm-svn: 325386
Before the endianness was specified on each call to read
or write of the StreamReader / StreamWriter, but in practice
it's extremely rare for streams to have data encoded in
multiple different endiannesses, so we should optimize for the
99% use case.
This makes the code cleaner and more general, but otherwise
has NFC.
llvm-svn: 296415
This was reverted because it was breaking some builds, and
because of incorrect error code usage. Since the CL was
large and contained many different things, I'm resubmitting
it in pieces.
This portion is NFC, and consists of:
1) Renaming classes to follow a consistent naming convention.
2) Fixing the const-ness of the interface methods.
3) Adding detailed doxygen comments.
4) Fixing a few instances of passing `const BinaryStream& X`. These
are now passed as `BinaryStreamRef X`.
llvm-svn: 296394
r296215, "[PDB] General improvements to Stream library."
r296217, "Disable BinaryStreamTest.StreamReaderObject temporarily."
r296220, "Re-enable BinaryStreamTest.StreamReaderObject."
r296244, "[PDB] Disable some tests that are breaking bots."
r296249, "Add static_cast to silence -Wc++11-narrowing."
std::errc::no_buffer_space should be used for OS-oriented errors for socket transmission.
(Seek discussions around llvm/xray.)
I could substitute s/no_buffer_space/others/g, but I revert whole them ATM.
Could we define and use LLVM errors there?
llvm-svn: 296258
This adds various new functionality and cleanup surrounding the
use of the Stream library. Major changes include:
* Renaming of all classes for more consistency / meaningfulness
* Addition of some new methods for reading multiple values at once.
* Full suite of unit tests for reader / writer functionality.
* Full set of doxygen comments for all classes.
* Streams now store their own endianness.
* Fixed some bugs in a few of the classes that were discovered
by the unit tests.
llvm-svn: 296215
