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Fix 'MIPS: Fix Utf16CharacterStream scanner crash due to missaligned access'

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Removed a wrong condition test in  TwoByteExternalBufferedStream. This changed fixes errors that may occur under some conditions.

Review-Url: https://codereview.chromium.org/2469723002
Cr-Commit-Position: refs/heads/master@{#40722}
This commit is contained in:
predrag.rudic 2016-11-03 05:31:51 -07:00 committed by Commit bot
parent 9b308dcaf5
commit f04a9b4936
2 changed files with 17 additions and 11 deletions
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26
src/parsing/scanner-character-streams.cc
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@ -537,7 +537,7 @@ size_t OneByteExternalStreamingStream::FillBuffer(size_t position) {
return len;
}
#if !(V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM)
#if !(V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64)
// ----------------------------------------------------------------------------
// TwoByteExternalStreamingStream
//
@ -703,6 +703,7 @@ bool TwoByteExternalBufferedStream::ReadBlock() {
DCHECK_EQ(position, pos());
return true;
} else {
buffer_start_ = buffer_;
buffer_pos_ = position;
buffer_cursor_ = buffer_;
buffer_end_ = buffer_ + FillBuffer(position, chunk_no);
@ -714,6 +715,8 @@ bool TwoByteExternalBufferedStream::ReadBlock() {
size_t TwoByteExternalBufferedStream::FillBuffer(size_t position,
size_t chunk_no) {
DCHECK_EQ(chunks_[chunk_no].byte_pos % 2, 1);
bool odd_start = true;
// Align buffer_pos_ to the size of the buffer.
{
size_t new_pos = position / kBufferSize * kBufferSize;
@ -722,6 +725,7 @@ size_t TwoByteExternalBufferedStream::FillBuffer(size_t position,
buffer_pos_ = new_pos;
buffer_cursor_ = buffer_start_ + (position - buffer_pos_);
position = new_pos;
odd_start = chunks_[chunk_no].byte_pos % 2;
}
}
@ -742,18 +746,18 @@ size_t TwoByteExternalBufferedStream::FillBuffer(size_t position,
}
// Common case: character is in current chunk.
DCHECK_LE(current->byte_pos, 2 * position + 1);
DCHECK_LE(current->byte_pos, 2 * position + odd_start);
DCHECK_LT(2 * position + 1, current->byte_pos + current->byte_length);
// Copy characters from current chunk starting from chunk_pos to the end of
// buffer or chunk.
size_t chunk_pos = position - current->byte_pos / 2;
bool middle_of_chunk = chunk_pos != 0;
size_t start_offset = odd_start && chunk_pos != 0;
size_t bytes_to_move =
i::Min(2 * kBufferSize - !middle_of_chunk,
current->byte_length - 2 * chunk_pos + middle_of_chunk);
i::MemMove(reinterpret_cast<uint8_t*>(buffer_) + !middle_of_chunk,
current->data + 2 * chunk_pos - middle_of_chunk, bytes_to_move);
i::Min(2 * kBufferSize - lonely_byte,
current->byte_length - 2 * chunk_pos + start_offset);
i::MemMove(reinterpret_cast<uint8_t*>(buffer_) + lonely_byte,
current->data + 2 * chunk_pos - start_offset, bytes_to_move);
// Fill up the rest of the buffer if there is space and data left.
totalLength += bytes_to_move;
@ -761,10 +765,11 @@ size_t TwoByteExternalBufferedStream::FillBuffer(size_t position,
if (position - buffer_pos_ < kBufferSize) {
chunk_no = FindChunk(chunks_, source_, 2 * position + 1);
current = &chunks_[chunk_no];
odd_start = current->byte_pos % 2;
bytes_to_move = i::Min(2 * kBufferSize - totalLength, current->byte_length);
while (bytes_to_move && current->byte_pos % 2) {
while (bytes_to_move) {
// Common case: character is in current chunk.
DCHECK_LE(current->byte_pos, 2 * position + 1);
DCHECK_LE(current->byte_pos, 2 * position + odd_start);
DCHECK_LT(2 * position + 1, current->byte_pos + current->byte_length);
i::MemMove(reinterpret_cast<uint8_t*>(buffer_) + totalLength,
@ -773,6 +778,7 @@ size_t TwoByteExternalBufferedStream::FillBuffer(size_t position,
position = (current->byte_pos + current->byte_length) / 2;
chunk_no = FindChunk(chunks_, source_, 2 * position + 1);
current = &chunks_[chunk_no];
odd_start = current->byte_pos % 2;
bytes_to_move =
i::Min(2 * kBufferSize - totalLength, current->byte_length);
}
@ -820,7 +826,7 @@ Utf16CharacterStream* ScannerStream::For(
v8::ScriptCompiler::StreamedSource::Encoding encoding) {
switch (encoding) {
case v8::ScriptCompiler::StreamedSource::TWO_BYTE:
#if !(V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64 || V8_TARGET_ARCH_ARM)
#if !(V8_TARGET_ARCH_MIPS || V8_TARGET_ARCH_MIPS64)
return new TwoByteExternalStreamingStream(source_stream);
#else
return new TwoByteExternalBufferedStream(source_stream);

2
test/cctest/parsing/test-scanner-streams.cc
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@ -27,7 +27,7 @@ class ChunkSource : public v8::ScriptCompiler::ExternalSourceStream {
// If extra_chunky, we'll use increasingly large chunk sizes.
// If not, we'll have a single chunk of full length.
size_t chunk_size = extra_chunky ? 1 : len;
for (size_t i = 0; i < len; i += chunk_size, chunk_size *= 2) {
for (size_t i = 0; i < len; i += chunk_size, chunk_size++) {
chunks_.push_back({data + i, i::Min(chunk_size, len - i)});
}
chunks_.push_back({nullptr, 0});