diff options
Diffstat (limited to 'chapter21/src/main/java/com')
5 files changed, 102 insertions, 119 deletions
diff --git a/chapter21/src/main/java/com/seaofnodes/simple/Parser.java b/chapter21/src/main/java/com/seaofnodes/simple/Parser.java index e1120a2f..219c3c44 100644 --- a/chapter21/src/main/java/com/seaofnodes/simple/Parser.java +++ b/chapter21/src/main/java/com/seaofnodes/simple/Parser.java @@ -144,7 +144,25 @@ public class Parser { // Parse whole program, as-if function header "{ int arg -> body }" parseFunctionBody(_code._main,loc(),"arg"); - _code.link(_code._main)._name = "main"; + + // Kill an empty default main. Keep only if it was explicitly defined + // (programmer asked for a "main") or it has stuff (i.e. beginner + // default main). + FunNode main = _code.link(_code._main); + StopNode stop = _code._stop; + if( main.ret().expr() instanceof ConstantNode && main.ret().mem().in(0)==main && stop.nIns() > 1 ) { + // Kill an empty default main; so it does not attempt to put a + // "main" in any final ELF file + stop.delDef(stop._inputs.find(main.ret())); + } else { + // We have a non-empty default main. + // Check for an explicit main + for( Node n : stop._inputs ) + if( n instanceof FunNode fun && fun._name.equals("main") ) + // Found an explicit "main" AND we have a default "main" + throw error("Cannot define both an explicit main and a default main"); + main._name = "main"; + } if( !_lexer.isEOF() ) throw _errorSyntax("unexpected"); @@ -154,7 +172,7 @@ public class Parser { for( StructNode init : INITS.values() ) init.unkeep().kill(); INITS.clear(); - _code._stop.peephole(); + stop.peephole(); if( show ) showGraph(); } diff --git a/chapter21/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java b/chapter21/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java index 32c41b16..64ea8201 100644 --- a/chapter21/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java +++ b/chapter21/src/main/java/com/seaofnodes/simple/codegen/CodeGen.java @@ -4,7 +4,6 @@ import com.seaofnodes.simple.*; import com.seaofnodes.simple.node.*; import com.seaofnodes.simple.print.*; import com.seaofnodes.simple.type.*; -import java.io.ByteArrayOutputStream; import java.io.IOException; import java.util.BitSet; import java.util.HashMap; @@ -327,8 +326,8 @@ public class CodeGen { public CodeGen exportELF(String fname) throws IOException { assert _phase == Phase.Encoding; _phase = Phase.Export; - ElfFile obj = new ElfFile(this); - obj.export(fname); + if( fname == null ) new LinkMem(this).link(); // In memory patching + else new ElfFile(this).export(fname); // External ELF file return this; } diff --git a/chapter21/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java b/chapter21/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java index 6aed0fae..223911ba 100644 --- a/chapter21/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java +++ b/chapter21/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java @@ -3,11 +3,11 @@ package com.seaofnodes.simple.codegen; import com.seaofnodes.simple.*; import com.seaofnodes.simple.node.*; import com.seaofnodes.simple.type.*; +import com.seaofnodes.simple.codegen.Encoding.BAOS; import java.io.*; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.util.HashMap; -import java.util.Map; public class ElfFile { @@ -118,7 +118,7 @@ public class ElfFile { out.putLong(size()); // size out.putInt(_link); // link out.putInt(_info); // info - out.putLong(1); // addralign + out.putLong(16); // addralign if (_type == 2) { out.putLong(SYMBOL_SIZE);// entsize } else if (_type == 4) { @@ -160,7 +160,7 @@ public class ElfFile { } @Override - void write(ByteBuffer out) { + void write(ByteBuffer out) { // Index 0 both designates the first entry in the table and serves as the undefined symbol index for( int i = 0; i < SYMBOL_SIZE/4; i++ ) { out.putInt(0); @@ -175,7 +175,7 @@ public class ElfFile { } @Override - int size() { + int size() { return (1 + _symbols.len() + _loc.len()) * SYMBOL_SIZE; } } @@ -244,7 +244,10 @@ public class ElfFile { text._flags = SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR; pushSection(text); - DataSection rdata = new DataSection(".rodata", 1 /* SHT_PROGBITS */); + // Build and write constant pool + BAOS cpool = new BAOS(); + _code._encoding.writeConstantPool(cpool,false); + DataSection rdata = new DataSection(".rodata", 1 /* SHT_PROGBITS */, cpool); rdata._flags = SHF_ALLOC; pushSection(rdata); @@ -262,13 +265,12 @@ public class ElfFile { // calculate local index int num = 1; - for( Symbol s : symbols._loc ) { + for( Symbol s : symbols._loc ) s._index = num++; - } int start_global = symbols._loc.size(); - for(Symbol a: symbols._symbols) { + for(Symbol a: symbols._symbols) a._index = start_global++; - } + // create .text relocations DataSection text_rela = new DataSection(".rela.text", 4 /* SHT_RELA */); for( Node n : _code._encoding._externals.keySet()) { diff --git a/chapter21/src/main/java/com/seaofnodes/simple/codegen/Encoding.java b/chapter21/src/main/java/com/seaofnodes/simple/codegen/Encoding.java index 065a555f..0f9aac89 100644 --- a/chapter21/src/main/java/com/seaofnodes/simple/codegen/Encoding.java +++ b/chapter21/src/main/java/com/seaofnodes/simple/codegen/Encoding.java @@ -44,6 +44,9 @@ public class Encoding { public int [] _opStart; // Start of opcodes, by _nid public byte[] _opLen; // Length of opcodes, by _nid + // Big Constant relocation info + public final HashMap<Node,Type> _bigCons = new HashMap<>(); + Encoding( CodeGen code ) { _code = code; } // Shortcut to the defining register @@ -51,23 +54,6 @@ public class Encoding { return _code._regAlloc.regnum(n); } - public Encoding add1( int op ) { _bits.write(op); return this; } - - public void add2( int op ) { - _bits.write(op ); - _bits.write(op>> 8); - } - // Little endian write of a 32b opcode - public void add4( int op ) { - _bits.write(op ); - _bits.write(op>> 8); - _bits.write(op>>16); - _bits.write(op>>24); - } - public void add8( long i64 ) { - add4((int) i64 ); - add4((int)(i64>>32)); - } public int read1(int idx) { byte[] buf = _bits.buf(); return (buf[idx]&0xFF); @@ -96,11 +82,32 @@ public class Encoding { buf[idx+3] = (byte)(val>>24); } - void pad(int n) { - while( (_bits.size()+n-1 & -n) > _bits.size() ) - _bits.write(0); + static void padN(int n, BAOS bits) { + while( (bits.size()+n-1 & -n) > bits.size() ) + bits.write(0); } + // Convenience for writing log-N + static void addN( int log, Type t, BAOS bits ) { + long x = t instanceof TypeInteger ti + ? ti.value() + : log==3 + ? Double.doubleToRawLongBits( ((TypeFloat)t).value()) + : Float.floatToRawIntBits((float)((TypeFloat)t).value()); + addN(log,x,bits); + } + static void addN( int log, long x, BAOS bits ) { + for( int i=0; i < 1<<log; i++ ) { + bits.write((int)x); + x >>= 8; + } + } + + public Encoding add1( int op ) { addN(0,op,_bits); return this; } + public Encoding add2( int op ) { addN(1,op,_bits); return this; } + public Encoding add4( int op ) { addN(2,op,_bits); return this; } + public Encoding add8(long op ) { addN(3,op,_bits); return this; } + // Nodes need "relocation" patching; things done after code is placed. // Record src and dst Nodes. @@ -128,7 +135,6 @@ public class Encoding { // Store t as a 32/64 bit constant in the code space; generate RIP-relative // addressing to load it - public final HashMap<Node,Type> _bigCons = new HashMap<>(); public void largeConstant( Node relo, Type t ) { assert t.isConstant(); _bigCons.put(relo,t); @@ -148,13 +154,6 @@ public class Encoding { // Short-form RIP-relative support: replace long encodings with short // encodings and compact the code, changing all the offsets. compactShortForm(); - - // Write any large constants into a constant pool; they - // are accessed by RIP-relative addressing. - writeConstantPool(true); - - // Patch RIP-relative and local encodings now. - patchLocalRelocations(); } // Basic block layout: invert branches to keep blocks in-order; insert @@ -277,7 +276,7 @@ public class Encoding { if( !(bb instanceof MachNode mach0) ) _opStart[bb._nid] = _bits.size(); else if( bb instanceof FunNode fun ) { - pad(16); + padN(16,_bits); _fun = fun; // Currently encoding function _opStart[bb._nid] = _bits.size(); mach0.encoding( this ); @@ -291,7 +290,7 @@ public class Encoding { } } } - pad(16); + padN(16,_bits); } // Short-form RIP-relative support: replace short encodings with long @@ -315,6 +314,11 @@ public class Encoding { slide = 0; for( int i=0; i<len; i++ ) { CFGNode bb = _code._cfg.at(i); + // Functions pad to align 16 + if( bb instanceof FunNode ) { + int newStart = _opStart[bb._nid]+slide; + slide += (newStart+15 & -16)-newStart; + } _opStart[bb._nid] += slide; if( bb instanceof RIPRelSize riprel ) { CFGNode target = ((CFGNode)bb.out(0)).uctrlSkipEmpty(); @@ -332,12 +336,6 @@ public class Encoding { } } } - - // CPool padding is non-linear; in rare cases padding can force a - // larger size... which will shrink the padding and allow the - // short form to work. Too bad. - if( !_cpool.isEmpty() ) - pad(8); } @@ -358,18 +356,16 @@ public class Encoding { } } - // Write the constant pool; either into the code space - // and patch locally, or into another BAOS for emission - // to the ELF file. - public final HashMap<Node,Integer> _cpool = new HashMap<>(); - public final BAOS _cbits = new BAOS(); - private void writeConstantPool(boolean elf) { + + // Write the constant pool into the BAOS and optionally patch locally + void writeConstantPool( BAOS bits, boolean patch ) { HashSet<Type> ts = new HashSet<>(); for( Type t : _bigCons.values() ) { if( ts.contains(t) ) throw Utils.TODO(); // Dup! Compress! ts.add(t); } + padN(16,bits); // By log size for( int log = 3; log >= 0; log-- ) { @@ -377,82 +373,32 @@ public class Encoding { for( Node relo : _bigCons.keySet() ) { Type t = _bigCons.get(relo); if( t.log_size()==log ) { - // Map from relo to constant start - // Else local patch - int target = _bits.size(); - int start = _opStart[relo._nid]; - ((RIPRelSize)relo).patch(this, start, _opLen[relo._nid], target - start); - if( t instanceof TypeTuple tt ) { + // Map from relo to constant start and patch + if( patch ) { + int target = _bits.size(); + int start = _opStart[relo._nid]; + ((RIPRelSize)relo).patch(this, start, _opLen[relo._nid], target - start); + } + // Put constant into code space. + if( t instanceof TypeTuple tt ) // Constant tuples put all entries for( Type tx : tt._types ) - addN(log,tx); - } else - addN(log,t); - //if( elf ) _cbits.write8(x); - //else { - //} + addN(log,tx,bits); + else + addN(log,t,bits); } } } } - private void addN( int log, Type t ) { - long x = t instanceof TypeInteger ti - ? ti.value() - : log==3 - ? Double.doubleToRawLongBits( ((TypeFloat)t).value()) - : Float.floatToRawIntBits((float)((TypeFloat)t).value()); - switch(log) { - case 0: add1((int)x); break; - case 1: add2((int)x); break; - case 2: add4((int)x); break; - case 3: add8( x); break; - } - } - // Patch local encodings now - private void patchLocalRelocations() { + void patchLocalRelocations() { // Walk the local code-address relocations for( Node src : _internals.keySet() ) { - Node dst = _internals.get(src); + Node dst = _internals.get(src); int target = _opStart[dst._nid]; int start = _opStart[src._nid]; ((RIPRelSize)src).patch(this, start, _opLen[src._nid], target - start); } - - for( Node src : _cpool.keySet() ) { - int target = _cpool.get(src); - int start = _opStart[src._nid]; - ((RIPRelSize)src).patch(this, start, _opLen[src._nid], target - start); - } - } - - - // Actual stack layout is up to each CPU. - // X86, with too many args & spills: - // | CALLER | - // | argN | // slot 1, required by callER - // +--------+ - // | RPC | // slot 0, required by callER - // | callee | // slot 3, callEE - // | callee | // slot 2, callEE - // | PAD16 | - // +--------+ - - // RISC/ARM, with too many args & spills: - // | CALLER | - // | argN | // slot 0, required by callER - // +--------+ - // | callee | // slot 3, callEE: might be RPC - // | callee | // slot 2, callEE - // | callee | // slot 1, callEE - // | PAD16 | - // +--------+ - private void frameSize() { - for( Node n : _code._start.outs() ) { - if( n instanceof FunNode fun ) { - throw Utils.TODO(); - } - } } } diff --git a/chapter21/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java b/chapter21/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java new file mode 100644 index 00000000..35d2008a --- /dev/null +++ b/chapter21/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java @@ -0,0 +1,18 @@ +package com.seaofnodes.simple.codegen; + +// In-memory linking +public class LinkMem { + final CodeGen _code; + LinkMem( CodeGen code ) { _code = code; } + + public CodeGen link() { + // Write any large constants into a constant pool; they + // are accessed by RIP-relative addressing. + _code._encoding.writeConstantPool(_code._encoding._bits,true); + + // Patch RIP-relative and local encodings now. + _code._encoding.patchLocalRelocations(); + + return _code; + } +} |