From d32f97238c903765dec4e9a9f3cbfa5fd12cded6 Mon Sep 17 00:00:00 2001 From: Cliff Click Date: Mon, 10 Aug 2026 11:11:18 -0700 Subject: Chapter 25: Modules, Separate Compilation, and SSA Construction Co-authored-by: Hsiang-Ying Fu <66062782+fuhsnn@users.noreply.github.com> Co-authored-by: fuhsnn <66062782+fuhsnn@users.noreply.github.com> Co-authored-by: Symious <14933944+symious@users.noreply.github.com> Co-authored-by: Jun Kawasaki Co-authored-by: Claude Opus 5 --- .../com/seaofnodes/simple/node/StopCUNode.java | 122 +++++++++++++++++++++ 1 file changed, 122 insertions(+) create mode 100644 src/main/java/com/seaofnodes/simple/node/StopCUNode.java (limited to 'src/main/java/com/seaofnodes/simple/node/StopCUNode.java') diff --git a/src/main/java/com/seaofnodes/simple/node/StopCUNode.java b/src/main/java/com/seaofnodes/simple/node/StopCUNode.java new file mode 100644 index 00000000..ab0f5da6 --- /dev/null +++ b/src/main/java/com/seaofnodes/simple/node/StopCUNode.java @@ -0,0 +1,122 @@ +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 strs, HashMap types, IdentityHashMap 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 is an allocation helper, never an externally + // callable constructor when a user constructor exists. Otherwise + // the same no-arg 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 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