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Use unsigned integer arithmetic in Zone::NewExpand.

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BUG=328202
R=jkummerow@chromium.org
LOG=N

Review URL: https://codereview.chromium.org/108783005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@18564 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
dslomov@chromium.org 2014-01-13 13:00:09 +00:00
parent 38cde85729
commit da52e9106e
1 changed files with 19 additions and 10 deletions
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29
src/zone.cc
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@ -185,25 +185,31 @@ Address Zone::NewExpand(int size) {
// except that we employ a maximum segment size when we delete. This
// is to avoid excessive malloc() and free() overhead.
Segment* head = segment_head_;
int old_size = (head == NULL) ? 0 : head->size();
static const int kSegmentOverhead = sizeof(Segment) + kAlignment;
int new_size_no_overhead = size + (old_size << 1);
int new_size = kSegmentOverhead + new_size_no_overhead;
const size_t old_size = (head == NULL) ? 0 : head->size();
static const size_t kSegmentOverhead = sizeof(Segment) + kAlignment;
const size_t new_size_no_overhead = size + (old_size << 1);
size_t new_size = kSegmentOverhead + new_size_no_overhead;
const size_t min_new_size = kSegmentOverhead + static_cast<size_t>(size);
// Guard against integer overflow.
if (new_size_no_overhead < size || new_size < kSegmentOverhead) {
if (new_size_no_overhead < static_cast<size_t>(size) ||
new_size < static_cast<size_t>(kSegmentOverhead)) {
V8::FatalProcessOutOfMemory("Zone");
return NULL;
}
if (new_size < kMinimumSegmentSize) {
if (new_size < static_cast<size_t>(kMinimumSegmentSize)) {
new_size = kMinimumSegmentSize;
} else if (new_size > kMaximumSegmentSize) {
} else if (new_size > static_cast<size_t>(kMaximumSegmentSize)) {
// Limit the size of new segments to avoid growing the segment size
// exponentially, thus putting pressure on contiguous virtual address space.
// All the while making sure to allocate a segment large enough to hold the
// requested size.
new_size = Max(kSegmentOverhead + size, kMaximumSegmentSize);
new_size = Max(min_new_size, static_cast<size_t>(kMaximumSegmentSize));
}
Segment* segment = NewSegment(new_size);
if (new_size > INT_MAX) {
V8::FatalProcessOutOfMemory("Zone");
return NULL;
}
Segment* segment = NewSegment(static_cast<int>(new_size));
if (segment == NULL) {
V8::FatalProcessOutOfMemory("Zone");
return NULL;
@ -213,7 +219,10 @@ Address Zone::NewExpand(int size) {
Address result = RoundUp(segment->start(), kAlignment);
position_ = result + size;
// Check for address overflow.
if (position_ < result) {
// (Should not happen since the segment is guaranteed to accomodate
// size bytes + header and alignment padding)
if (reinterpret_cast<uintptr_t>(position_)
< reinterpret_cast<uintptr_t>(result)) {
V8::FatalProcessOutOfMemory("Zone");
return NULL;
}