As proposed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-October/106595.html
This change also fixes an API oddity where BitstreamCursor::Read() would
return zero for the first read past the end of the bitstream, but would
report_fatal_error for subsequent reads. Now we always report_fatal_error
for all reads past the end. Updated clients to check for the end of the
bitstream before reading from it.
I also needed to add padding to the invalid bitcode tests in
test/Bitcode/. This is because the streaming interface was not checking that
the file size is a multiple of 4.
Differential Revision: https://reviews.llvm.org/D26219
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@285773 91177308-0d34-0410-b5e6-96231b3b80d8
Explicitly check that artificial byte limit is rounded correctly by
exposing BitstreamReader::Size through a new accessor, getSizeIfKnown.
The original code for rounding (from r264547) wasn't obviously correct,
and even though r264623 cleaned it up (by calling llvm::alignTo) I think
it's worth testing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264650 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264549 91177308-0d34-0410-b5e6-96231b3b80d8
Allow users of SimpleBitstreamCursor to limit the number of bytes
available to the cursor. This is preparation for instantiating a cursor
that isn't allowed to load more bytes from a StreamingMemoryObject (just
move around the ones already-loaded).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264547 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264546 91177308-0d34-0410-b5e6-96231b3b80d8
This avoids an issue where AtEndOfStream mistakenly returns true at the /start/ of
a stream.
(In the rare case that the size is known and actually 0, the slow path will still
handle it correctly.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221840 91177308-0d34-0410-b5e6-96231b3b80d8
