From 75390f477ac7d4568ac02f97358d146ff9879d6e Mon Sep 17 00:00:00 2001 From: Cliff Click Date: Mon, 28 Sep 2026 15:42:57 -0700 Subject: Backport FunPtr Helps keep functions alive via ptr only (no calls). A few RISC 5 TFP encoding fixes. --- chapter23/src/main/java/com/seaofnodes/simple/Parser.java | 2 +- .../main/java/com/seaofnodes/simple/codegen/CodeGen.java | 4 +++- .../main/java/com/seaofnodes/simple/codegen/ElfFile.java | 1 + .../java/com/seaofnodes/simple/node/ConstantNode.java | 4 ++++ .../src/main/java/com/seaofnodes/simple/node/FunNode.java | 10 ++++++++++ .../main/java/com/seaofnodes/simple/node/FunPtrNode.java | 13 +++++++++++++ .../com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java | 15 ++++----------- 7 files changed, 36 insertions(+), 13 deletions(-) create mode 100644 chapter23/src/main/java/com/seaofnodes/simple/node/FunPtrNode.java (limited to 'chapter23/src/main/java') diff --git a/chapter23/src/main/java/com/seaofnodes/simple/Parser.java b/chapter23/src/main/java/com/seaofnodes/simple/Parser.java index be5c8932..5b3f4d1a 100644 --- a/chapter23/src/main/java/com/seaofnodes/simple/Parser.java +++ b/chapter23/src/main/java/com/seaofnodes/simple/Parser.java @@ -1618,7 +1618,7 @@ public class Parser { // Make a concrete function type, with a fidx TypeFunPtr tfp = _code.makeFun(TypeFunPtr.make(false,false,ts.asAry(),Type.BOTTOM)); ReturnNode ret = parseFunctionBody(tfp,loc,ids.asAry()); - return con(ret._fun.sig()); + return new FunPtrNode(ret._fun.sig(),ret).peephole(); } /** diff --git a/chapter23/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java b/chapter23/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java index adfefae5..50490689 100644 --- a/chapter23/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java +++ b/chapter23/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java @@ -194,7 +194,7 @@ public class CodeGen { for( int i=0; i<_start.nOuts(); i++ ) { Node use = _start.out(i); if( use instanceof FunNode fun && - fun.nIns()==2 && fun.in(1)==_start && fun != main && + fun.nIns()==2 && fun.in(1)==_start && fun != main && !fun.hasPtr() && (fun._name==null || fun._name.startsWith("sys.")) ) { add(fun).setDef(1,Parser.XCTRL); addAll(fun._outputs); @@ -353,6 +353,8 @@ public class CodeGen { // Produce a machine node from n; map it to flag as done so stops cycles. map.put(n, x=_mach.instSelect(n) ); + // Stop retains the callable body. Its lifetime edge is not a machine operand. + if( n instanceof FunPtrNode ) x._inputs.pop(); // Walk machine op and replace inputs with mapped inputs for( int i=0; i < x.nIns(); i++ ) x._inputs.set(i, _instSelect(x.in(i),map) ); diff --git a/chapter23/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java b/chapter23/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java index 8f9e2981..b6267600 100644 --- a/chapter23/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java +++ b/chapter23/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java @@ -222,6 +222,7 @@ public class ElfFile { i++; int end = _code._encoding._opStart[ret._nid] + _code._encoding._opLen[ret._nid]; + if( fun._name==null ) continue; // Anonymous addresses are relocated within .text. Symbol func = new Symbol(fun._name, text._index, SYM_BIND_GLOBAL, SYM_TYPE_FUNC); func._value = _code._encoding._opStart[fun._nid]; func._size = end - func._value; diff --git a/chapter23/src/main/java/com/seaofnodes/simple/node/ConstantNode.java b/chapter23/src/main/java/com/seaofnodes/simple/node/ConstantNode.java index 8fd0e61e..0d7c0964 100644 --- a/chapter23/src/main/java/com/seaofnodes/simple/node/ConstantNode.java +++ b/chapter23/src/main/java/com/seaofnodes/simple/node/ConstantNode.java @@ -27,6 +27,10 @@ public class ConstantNode extends Node { public static Node make( Type type ) { if( type==Type. CONTROL ) return new CtrlNode(); if( type==Type.XCONTROL ) return new XCtrlNode(); + if( type instanceof TypeFunPtr tfp && tfp.isConstant() && tfp.notNull() ) { + FunNode fun = CodeGen.CODE.link(tfp); + if( fun!=null && !fun.isDead() ) return new FunPtrNode(tfp,fun.ret()); + } return new ConstantNode(type); } diff --git a/chapter23/src/main/java/com/seaofnodes/simple/node/FunNode.java b/chapter23/src/main/java/com/seaofnodes/simple/node/FunNode.java index 88f5dc18..e7d6c3a6 100644 --- a/chapter23/src/main/java/com/seaofnodes/simple/node/FunNode.java +++ b/chapter23/src/main/java/com/seaofnodes/simple/node/FunNode.java @@ -61,6 +61,16 @@ public class FunNode extends RegionNode { public void setRet(ReturnNode ret) { _ret=ret; } public ReturnNode ret() { assert _ret!=null; return _ret; } + // Direct calls are known; any other use of an address may have unknown callers. + public boolean hasPtr() { + for( Node use : ret()._outputs ) + if( use instanceof FunPtrNode ) + for( Node user : use._outputs ) + if( !(user instanceof CallNode call) || call.fptr()!=use || + call._inputs.find(use)!=call.nIns()-1 ) return true; + return false; + } + // Signature can improve over time public TypeFunPtr sig() { return _sig; } public void setSig( TypeFunPtr sig ) { diff --git a/chapter23/src/main/java/com/seaofnodes/simple/node/FunPtrNode.java b/chapter23/src/main/java/com/seaofnodes/simple/node/FunPtrNode.java new file mode 100644 index 00000000..7f32698e --- /dev/null +++ b/chapter23/src/main/java/com/seaofnodes/simple/node/FunPtrNode.java @@ -0,0 +1,13 @@ +package com.seaofnodes.simple.node; + +import com.seaofnodes.simple.type.TypeFunPtr; + +// A function address keeps its body alive, even without a linked Call. +public class FunPtrNode extends ConstantNode { + public FunPtrNode(TypeFunPtr tfp, ReturnNode ret) { + super(tfp); + addDef(ret); + } + public ReturnNode ret() { return (ReturnNode)in(1); } + @Override public String uniqueName() { return "FunPtr_"+_nid; } +} diff --git a/chapter23/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java b/chapter23/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java index 7e057507..db140304 100644 --- a/chapter23/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java +++ b/chapter23/src/main/java/com/seaofnodes/simple/node/cpus/riscv/TFPRISC.java @@ -26,22 +26,15 @@ public class TFPRISC extends ConstantNode implements MachNode, RIPRelSize { enc.add4(riscv.i_type(riscv.OP_IMM, dst, 0, dst, 0)); } - @Override public byte encSize(int delta) { - if( -(1L<<11) <= delta && delta < (1L<<11) ) return 4; - throw Utils.TODO(); - } + @Override public byte encSize(int delta) { return 8; } // Delta is from opcode start @Override public void patch( Encoding enc, int opStart, int opLen, int delta ) { short rpc = enc.reg(this); if( opLen==8 ) { - // AUIPC (upper 20 bits) - // opstart of add - int next = opStart + opLen; - enc.patch4(opStart,riscv.u_type(riscv.OP_AUIPC, rpc, delta>>12)); - // addi(low 12 bits) - enc.patch4(next,riscv.i_type(riscv.OP_IMM, rpc, 0, rpc, delta & 0xFFF)); - // addi + // ADDI sign-extends its low 12 bits, so round the AUIPC high part. + enc.patch4(opStart ,riscv.u_type(riscv.OP_AUIPC, rpc, (delta+0x800)>>12)); + enc.patch4(opStart+4,riscv.i_type(riscv.OP_IMM, rpc, 0, rpc, delta & 0xFFF)); } else { // should not happen as one instruction is 4 byte, and TFP arm encodes 2. throw Utils.TODO(); -- cgit v1.2.3