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package com.seaofnodes.simple.node;
import com.seaofnodes.simple.codegen.CodeGen;
import com.seaofnodes.simple.type.*;
import com.seaofnodes.simple.util.BAOS;
import java.util.HashMap;
import java.util.IdentityHashMap;
// Stop of a single compilation unit, distinct from the outer whole-program Stop.
public class StopCUNode extends StopNode {
public StopCUNode() { super(); }
public StopCUNode(StopNode stop) { super(stop); }
@Override public Tag serialTag() { return Tag.StopCU; }
@Override public void packed( BAOS baos, HashMap<String,Integer> strs, HashMap<Type,Integer> types, IdentityHashMap<Node, Integer> anodes ) { baos.packed1(nIns()); }
static Node make( BAOS bais ) {
StopCUNode stop = new StopCUNode();
stop.setDefX(bais.packed1()-1,null);
return stop;
}
public StartCUNode start() {
for( Node use : _outputs )
if( use instanceof StartCUNode start )
return start;
return null;
}
@Override
public TypeTuple compute() {
// During Parsing, new Stops and Returns are being added. This Stop
// cannot know if more are coming, so must assume the worst.
if( CodeGen.CODE._phase ==null || CodeGen.CODE._phase == CodeGen.Phase.Parse )
return TypeTuple.STATE;
StartCUNode start = start();
// Memory start from all returns
TypeMem xmem = TypeMem.START;
// Escape summaries are monotone discovery facts. In Opto, a Return
// can widen from a precise set to FULL; the public-only normalization
// below must not forget private bits already discovered precisely from
// that Return on an earlier SCCP step.
if( CodeGen.CODE._phase == CodeGen.Phase.Opto &&
_type instanceof TypeTuple old && old.mem() instanceof TypeMem omem )
xmem = xmem.makeFrom(XInt.meet(xmem._escFs,omem._escFs),
XInt.meet(xmem._escAs,omem._escAs));
for( Node def : _inputs ) {
ReturnNode ret = (ReturnNode)def;
if( ret._type == Type.TOP ) continue;
if( !(ret._type instanceof TypeTuple tret) )
return TypeTuple.STATE; // Must be Type.BOTTOM
FunNode fun = ret.fun();
boolean noUserCtor = fun.isInstance() &&
!CodeGen.hasUserConstructor(((TypeMemPtr)fun.sig().arg(0))._obj);
// Instance <init> is an allocation helper, never an externally
// callable constructor when a user constructor exists. Otherwise
// the same no-arg <init> is the public constructor.
boolean pub = fun.isPublic() && (fun.isClz() || noUserCtor);
TypeFunPtr sig = fun.sig();
// If public init, the function escapes and the related class escapes
if( pub ) {
xmem = xmem.escapes(sig);
// Classes also escape their public clazz pointer, which then
// escapes all their public fields. Private fields do not
// escape, and are only available from the local class code.
if( fun.isClz() )
xmem = xmem.escapesAliases(sig._sig[0]);
}
// The instance <init> Start edge supplies conservative pre-Opto
// inputs, but its private-memory result is consumed only by the
// allocation sequence and is never an externally visible return.
if( fun.isInstance() && !noUserCtor ) continue;
// Does this function escape? If not, then no need to MEET
// here as its effects are not visible to the outside world.
addDepForwards(start); // Check again if function escapes
if( pub || start.escapedFIDX(sig.fidx()) ) {
if( tret.ctl().isHigh() ) continue; // Return not reachable
// Capture (precisely?) all escaping pointer aliases and fidxs.
// Escaped fidxs means the linked world can call that function;
// escaped aliases means the linked world can R/W those aliases.
xmem = xmem.escapes(tret.ret());
xmem = publicBottom(xmem);
xmem = (TypeMem)xmem.meet(publicBottom(tret.mem(),xmem));
}
}
assert xmem._alias==1 && !xmem._one;
return TypeTuple.make(Type.CONTROL,xmem,Type.BOTTOM);
}
// FULL escape sets arise from global BOTTOM. Across a compilation-unit
// boundary global BOTTOM exposes every public field, while retaining any
// private escapes already discovered precisely.
private TypeMem publicBottom(TypeMem mem) { return publicBottom(mem,mem); }
private TypeMem publicBottom(TypeMem mem, TypeMem prior) {
// The pessimistic Iter pass naturally lifts transient FULL inputs to
// precise finite sets. Replacing FULL early there would let a later
// input refinement add bits, reversing Iter's monotonic direction.
// This normalization is needed only for Opto's optimistic grand cycle.
if( CodeGen.CODE._phase != CodeGen.Phase.Opto ) return mem;
int[] escFs = XInt.isHigh(mem._escFs)
? XInt.meet(prior._escFs,CodeGen.CODE.publicFIDXs())
: mem._escFs;
int[] escAs = XInt.isHigh(mem._escAs)
? XInt.meet(prior._escAs,CodeGen.CODE.publicAliases())
: mem._escAs;
return escFs==mem._escFs && escAs==mem._escAs ? mem : mem.makeFrom(escFs,escAs);
}
@Override
public Node idealize() {
int len = nIns();
for( int i=0; i<nIns(); i++ )
if( in(i) instanceof ReturnNode ret && addDep(ret.fun()).isDead() )
delDef(i--);
if( len != nIns() ) return this;
return null;
}
}
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