The bitstream reader handles errors poorly. This has two effects:
* Bugs in file handling (especially modules) manifest as an "unexpected end of
file" crash
* Users of clang as a library end up aborting because the code unconditionally
calls `report_fatal_error`
The bitstream reader should be more resilient and return Expected / Error as
soon as an error is encountered, not way late like it does now. This patch
starts doing so and adopting the error handling where I think it makes sense.
There's plenty more to do: this patch propagates errors to be minimally useful,
and follow-ups will propagate them further and improve diagnostics.
https://bugs.llvm.org/show_bug.cgi?id=42311
<rdar://problem/33159405>
Differential Revision: https://reviews.llvm.org/D63518
llvm-svn: 364464
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
If this is a problem for anyone (shared_ptr is two pointers in size,
whereas IntrusiveRefCntPtr is 1 - and the ref count control block that
make_shared adds is probably larger than the one int in RefCountedBase)
I'd prefer to address this by adding a lower-overhead version of
shared_ptr (possibly refactoring IntrusiveRefCntPtr into such a thing)
to avoid the intrusiveness - this allows memory ownership to remain
orthogonal to types and at least to me, seems to make code easier to
understand (since no implicit ownership acquisition can happen).
This recommits 291006, reverted in r291007.
llvm-svn: 291016
If this is a problem for anyone (shared_ptr is two pointers in size,
whereas IntrusiveRefCntPtr is 1 - and the ref count control block that
make_shared adds is probably larger than the one int in RefCountedBase)
I'd prefer to address this by adding a lower-overhead version of
shared_ptr (possibly refactoring IntrusiveRefCntPtr into such a thing)
to avoid the intrusiveness - this allows memory ownership to remain
orthogonal to types and at least to me, seems to make code easier to
understand (since no implicit ownership acquisition can happen).
llvm-svn: 291006
The assertions were wrong; we need to call getEncodingData() on the element,
not the array. While here, simplify the skipRecord() implementation for Fixed
and Char6 arrays. This is tested by the code I added to llvm-bcanalyzer
which makes sure that we can skip any record.
Differential Revision: https://reviews.llvm.org/D27241
llvm-svn: 288315
As proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/106630.html
Move block info block state to a new class, BitstreamBlockInfo.
Clients may set the block info for a particular cursor with the
BitstreamCursor::setBlockInfo() method.
At this point BitstreamReader is not much more than a container for an
ArrayRef<uint8_t>, so remove it and replace all uses with direct uses
of memory buffers.
Differential Revision: https://reviews.llvm.org/D26259
llvm-svn: 286207
The implementation is fairly obvious. This is preparation for using
some blobs in bitcode.
For clarity (and perhaps future-proofing?), I moved the call to
JumpToBit in BitstreamCursor::readRecord ahead of calling
MemoryObject::getPointer, since JumpToBit can theoretically (a) read
bytes, which (b) invalidates the blob pointer.
This isn't strictly necessary the two memory objects we have:
- The return of RawMemoryObject::getPointer is valid until the memory
object is destroyed.
- StreamingMemoryObject::getPointer is valid until the next chunk is
read from the stream. Since the JumpToBit call is only going ahead
to a word boundary, we'll never load another chunk.
However, reordering makes it clear by inspection that the blob returned
by BitstreamCursor::readRecord will be valid.
I added some tests for StreamingMemoryObject::getPointer and
BitstreamCursor::readRecord.
llvm-svn: 264549
Add API to SimpleBitstreamCursor to allow users to translate between
byte addresses and pointers.
- jumpToPointer: move the bit position to a particular pointer.
- getPointerToByte: get the pointer for a particular byte.
- getPointerToBit: get the pointer for the byte of the current bit.
- getCurrentByteNo: convenience function for assertions and tests.
Mainly adds unit tests (getPointerToBit/Byte already has a use), but
also preparation for eventually using jumpToPointer.
llvm-svn: 264546
Split out SimpleBitstreamCursor from BitstreamCursor, which is a
lower-level cursor with no knowledge of bitcode blocks, abbreviations,
or records. It just knows how to read bits and navigate the stream.
This is mainly organizational, to separate the API for manipulating raw
bits from that for bitcode concepts like Record and Block.
llvm-svn: 264545
Optimize output of MDStrings in bitcode. This emits them in big blocks
(currently 1024) in a pair of records:
- BULK_STRING_SIZES: the sizes of the strings in the block, and
- BULK_STRING_DATA: a single blob, which is the concatenation of all
the strings.
Inspired by Mehdi's similar patch, http://reviews.llvm.org/D18342, this
should (a) slightly reduce bitcode size, since there is less record
overhead, and (b) greatly improve reading speed, since blobs are super
cheap to deserialize.
I needed to add support for blobs to streaming input to get the test
suite passing.
- StreamingMemoryObject::getPointer reads ahead and returns the
address of the blob.
- To avoid a possible reallocation of StreamingMemoryObject::Bytes,
BitstreamCursor::readRecord needs to move the call to JumpToEnd
forward so that getPointer is the last bitstream operation.
llvm-svn: 264409
Summary: This make readRecord 20% faster, measured on an LTO build
Reviewers: rafael
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D17911
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 262811
Summary:
Make sure the abbrev operands are valid and that we can read/skip them
afterwards.
Bug found with AFL fuzz.
Reviewers: rafael
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9030
llvm-svn: 235595
Eventually we can make some of these pass the error along to the caller.
Reports a fatal error if:
We find an invalid abbrev record
We try to get an invalid abbrev number
We can't fill the current word due to an EOF
Fixed an invalid bitcode test to check for output with FileCheck
Bugs found with afl-fuzz
llvm-svn: 226986
This doesn't change the interface or gives additional safety but removes
a ton of retain/release boilerplate.
No functionality change.
llvm-svn: 217778
Previously, BitstreamCursor read an abbreviated record by splatting the
whole thing into a data vector, then extracting and removing the /first/
element. Now, it reads the first element--the record code--separately from
the actual field values.
No (intended) functionality change.
llvm-svn: 181639
bitcode writer would generate abbrev records saying that the abbrev should be
filled with fixed zero-bit bitfields (this happens in the .bc writer when
the number of types used in a module is exactly one, since log2(1) == 0).
In this case, just handle it as a literal zero. We can't "just fix" the writer
without breaking compatibility with existing bc files, so have the abbrev reader
do the substitution.
Strengthen the assert in read to reject reads of zero bits so we catch such
crimes in the future, and remove the special case designed to handle this.
llvm-svn: 174801
BLOB (i.e., large, performance intensive data) in a bitcode file was switched to
invoking one virtual method call per byte read. Now we do one virtual call per
BLOB.
llvm-svn: 173065
through a BitstreamCursor that produce it: advance() and
advanceSkippingSubblocks(), representing the two most common ways clients
want to walk through bitcode.
llvm-svn: 172919
