SharedArrayRawBuffer*
SharedArrayRawBuffer::New(JSContext* cx, uint32_t length)
{
// The value (uint32_t)-1 is used as a signal in various places,
// so guard against it on principle.
MOZ_ASSERT(length != (uint32_t)-1);
// Add a page for the header and round to a page boundary.
uint32_t allocSize = SharedArrayAllocSize(length);
if (allocSize <= length)
return nullptr;
bool preparedForAsmJS = jit::JitOptions.asmJSAtomicsEnable && IsValidAsmJSHeapLength(length);
void* p = nullptr;
if (preparedForAsmJS) {
// Test >= to guard against the case where multiple extant runtimes
// race to allocate.
if (++numLive >= maxLive) {
JSRuntime* rt = cx->runtime();
if (rt->largeAllocationFailureCallback)
rt->largeAllocationFailureCallback(rt->largeAllocationFailureCallbackData);
if (numLive >= maxLive) {
numLive--;
return nullptr;
}
}
uint32_t mappedSize = SharedArrayMappedSize(allocSize);
// Get the entire reserved region (with all pages inaccessible)
p = MapMemory(mappedSize, false);
if (!p) {
numLive--;
return nullptr;
}
if (!MarkValidRegion(p, allocSize)) {
UnmapMemory(p, mappedSize);
numLive--;
return nullptr;
}
# if defined(MOZ_VALGRIND) && defined(VALGRIND_DISABLE_ADDR_ERROR_REPORTING_IN_RANGE)
// Tell Valgrind/Memcheck to not report accesses in the inaccessible region.
VALGRIND_DISABLE_ADDR_ERROR_REPORTING_IN_RANGE((unsigned char*)p + allocSize,
mappedSize - allocSize);
# endif
} else {
p = MapMemory(allocSize, true);
if (!p)
return nullptr;
}
uint8_t* buffer = reinterpret_cast<uint8_t*>(p) + gc::SystemPageSize();
uint8_t* base = buffer - sizeof(SharedArrayRawBuffer);
SharedArrayRawBuffer* rawbuf = new (base) SharedArrayRawBuffer(buffer, length, preparedForAsmJS);
MOZ_ASSERT(rawbuf->length == length); // Deallocation needs this
return rawbuf;
}
SharedArrayRawBuffer*
SharedArrayRawBuffer::New(JSContext* cx, uint32_t length)
{
// The value (uint32_t)-1 is used as a signal in various places,
// so guard against it on principle.
MOZ_ASSERT(length != (uint32_t)-1);
// Add a page for the header and round to a page boundary.
uint32_t allocSize = (length + 2*AsmJSPageSize - 1) & ~(AsmJSPageSize - 1);
if (allocSize <= length)
return nullptr;
#if defined(ASMJS_MAY_USE_SIGNAL_HANDLERS_FOR_OOB)
// Test >= to guard against the case where multiple extant runtimes
// race to allocate.
if (++numLive >= maxLive) {
JSRuntime* rt = cx->runtime();
if (rt->largeAllocationFailureCallback)
rt->largeAllocationFailureCallback(rt->largeAllocationFailureCallbackData);
if (numLive >= maxLive) {
numLive--;
return nullptr;
}
}
// Get the entire reserved region (with all pages inaccessible)
void* p = MapMemory(SharedArrayMappedSize, false);
if (!p) {
numLive--;
return nullptr;
}
if (!MarkValidRegion(p, allocSize)) {
UnmapMemory(p, SharedArrayMappedSize);
numLive--;
return nullptr;
}
# if defined(MOZ_VALGRIND) && defined(VALGRIND_DISABLE_ADDR_ERROR_REPORTING_IN_RANGE)
// Tell Valgrind/Memcheck to not report accesses in the inaccessible region.
VALGRIND_DISABLE_ADDR_ERROR_REPORTING_IN_RANGE((unsigned char*)p + allocSize,
SharedArrayMappedSize - allocSize);
# endif
#else
void* p = MapMemory(allocSize, true);
if (!p)
return nullptr;
#endif
uint8_t* buffer = reinterpret_cast<uint8_t*>(p) + AsmJSPageSize;
uint8_t* base = buffer - sizeof(SharedArrayRawBuffer);
return new (base) SharedArrayRawBuffer(buffer, length);
}