uint32_t
FrontEnd::calculateSizeOfStackAtlas(
bool encodeFourByteOffsets,
uint32_t numberOfSlotsMapped,
uint32_t bytesPerStackMap,
TR::Compilation *comp)
{
TR::CodeGenerator *cg = comp->cg();
TR::GCStackAtlas * stackAtlas = cg->getStackAtlas();
// Calculate the size of each individual map in the atlas. The fixed
// portion of the map contains:
//
// Low Code Offset (2 or 4)
// Stack map (depends on # of mapped parms/locals)
//
uint32_t sizeOfEncodedCodeOffsetInBytes = encodeFourByteOffsets ? 4 : 2;
uint32_t sizeOfSingleEncodedMapInBytes = sizeOfEncodedCodeOffsetInBytes;
sizeOfSingleEncodedMapInBytes += bytesPerStackMap;
// Calculate the atlas size
//
uint32_t atlasSize = sizeof(OMR::StackAtlasPOD);
ListIterator<TR_GCStackMap> mapIterator(&stackAtlas->getStackMapList());
TR_GCStackMap *mapCursor = mapIterator.getFirst();
while (mapCursor != NULL)
{
TR_GCStackMap *nextMapCursor = mapIterator.getNext();
if (!mapsAreIdentical(mapCursor, nextMapCursor, stackAtlas, comp))
{
atlasSize += sizeOfSingleEncodedMapInBytes;
}
mapCursor = nextMapCursor;
}
return atlasSize;
}
uint8_t *
FrontEnd::createStackAtlas(
bool encodeFourByteOffsets,
uint32_t numberOfSlotsMapped,
uint32_t bytesPerStackMap,
uint8_t *encodedAtlasBaseAddress,
uint32_t atlasSizeInBytes,
TR::Compilation *comp)
{
TR::CodeGenerator *cg = comp->cg();
TR::GCStackAtlas *stackAtlas = cg->getStackAtlas();
stackAtlas->setAtlasBits(encodedAtlasBaseAddress);
// Calculate the size of each individual map in the atlas. The fixed
// portion of the map contains:
//
// Low Code Offset (2 or 4)
// Stack map (depends on # of mapped parms/locals)
//
uint32_t sizeOfEncodedCodeOffsetInBytes = encodeFourByteOffsets ? 4 : 2;
uint32_t sizeOfSingleEncodedMapInBytes = sizeOfEncodedCodeOffsetInBytes;
sizeOfSingleEncodedMapInBytes += bytesPerStackMap;
// Encode the atlas
//
OMR::StackAtlasPOD *pyAtlas = (OMR::StackAtlasPOD *)encodedAtlasBaseAddress;
pyAtlas->numberOfMaps = stackAtlas->getNumberOfMaps();
pyAtlas->bytesPerStackMap = bytesPerStackMap;
// Offset to the MAPPED pyFrameObject parameter
//
pyAtlas->frameObjectParmOffset = 0;
// Lowest stack offset where MAPPED locals begin.
//
pyAtlas->localBaseOffset = stackAtlas->getLocalBaseOffset();
// Abort if we have overflowed the fields in pyAtlas.
//
if (bytesPerStackMap > USHRT_MAX ||
stackAtlas->getNumberOfMaps() > USHRT_MAX ||
stackAtlas->getNumberOfParmSlotsMapped() > USHRT_MAX ||
stackAtlas->getParmBaseOffset() < SHRT_MIN || stackAtlas->getParmBaseOffset() > SHRT_MAX ||
stackAtlas->getLocalBaseOffset() < SHRT_MIN || stackAtlas->getLocalBaseOffset() > SHRT_MAX)
{
comp->failCompilation<TR::CompilationException>("Overflowed the fields in pyAtlas");
}
// Maps are in reverse order in list from what we want in the atlas
// so advance to the address where the last map should go and start
// building the maps moving back toward the beginning of the atlas.
//
uint8_t *cursorInEncodedAtlas = encodedAtlasBaseAddress + atlasSizeInBytes;
ListIterator<TR_GCStackMap> mapIterator(&stackAtlas->getStackMapList());
TR_GCStackMap *mapCursor = mapIterator.getFirst();
while (mapCursor != NULL)
{
// Move back from the end of the atlas till the current map can be fit in,
// then pass the cursor to the routine that actually creates and fills in
// the stack map
//
TR_GCStackMap *nextMapCursor = mapIterator.getNext();
if (!mapsAreIdentical(mapCursor, nextMapCursor, stackAtlas, comp))
{
cursorInEncodedAtlas -= sizeOfSingleEncodedMapInBytes;
encodeStackMap(mapCursor, cursorInEncodedAtlas, encodeFourByteOffsets, bytesPerStackMap, comp);
}
mapCursor = nextMapCursor;
}
return encodedAtlasBaseAddress;
}
