Chapter 25: Modules, Separate Compilation, and SSA Constructionlinear

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 <jun784@gmail.com>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 0 insertions, 382 deletions

diff --git a/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java b/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java
deleted file mode 100644
index b6267600..00000000
--- a/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java
+++ /dev/null
@@ -1,382 +0,0 @@
-package com.seaofnodes.simple.codegen;
-
-import com.seaofnodes.simple.*;
-import com.seaofnodes.simple.codegen.Encoding.BAOS;
-import com.seaofnodes.simple.node.*;
-import com.seaofnodes.simple.type.*;
-import com.seaofnodes.simple.util.Ary;
-import java.io.*;
-import java.nio.ByteBuffer;
-import java.nio.ByteOrder;
-import java.util.HashMap;
-import java.util.Map;
-
-public class ElfFile {
-
-    final CodeGen _code;
-    Ary<Section> _sections = new Ary<>(Section.class);
-
-    ElfFile( CodeGen code ) { _code = code; }
-
-    public static int writeCString(DataSection strtab, String name) {
-        // place name in the string table
-        int pos = strtab._contents.size();
-        byte[] name_bytes = name.getBytes();
-        strtab._contents.write(name_bytes, 0, name_bytes.length);
-        // the strings are null terminated
-        strtab._contents.write(0);
-        return pos;
-    }
-
-    public static void write4( ByteArrayOutputStream bits, int op ) {
-        bits.write(op    );
-        bits.write(op>> 8);
-        bits.write(op>>16);
-        bits.write(op>>24);
-    }
-    public static void write8( ByteArrayOutputStream bits, long i64 ) {
-        write4(bits, (int) i64     );
-        write4(bits, (int)(i64>>32));
-    }
-
-    public static final int SYMBOL_SIZE = 4+1+1+2+8+8;
-
-    public static final int SYM_BIND_LOCAL   = 0;
-    public static final int SYM_BIND_GLOBAL  = 1;
-    public static final int SYM_BIND_WEAK    = 2;
-
-    public static final int SYM_TYPE_NOTYPE  = 0;
-    public static final int SYM_TYPE_OBJECT  = 1;
-    public static final int SYM_TYPE_FUNC    = 2;
-    public static final int SYM_TYPE_SECTION = 3;
-
-    public static class Symbol {
-        String _name;
-        int _name_pos;
-
-        // index in the symbol table
-        int _index;
-
-        // which section is it in
-        int _parent;
-
-        // depends on the symbol type
-        //   TODO
-        int _value, _size;
-
-        // top 4bits are the "bind", bottom 4 are "type"
-        int _info;
-
-        // bind 1011
-        // 00001111
-        // 10110000
-
-        Symbol(String name, int parent, int bind, int type) {
-            _name = name;
-            _parent = parent;
-            _info = (bind << 4) | (type & 0xF);
-        }
-
-        void writeHeader(ByteBuffer out) {
-            out.putInt(_name_pos);         // name
-            out.put((byte) _info);         // info
-            // default visibility
-            out.put((byte) 0);             // other
-            out.putShort((short) _parent); // shndx
-            out.putLong(_value);           // value
-            out.putLong(_size);            // size
-        }
-    }
-
-    public static final int SHF_WRITE     = 1;
-    public static final int SHF_ALLOC     = 2;
-    public static final int SHF_EXECINSTR = 4;
-    public static final int SHF_STRINGS   = 32;
-    public static final int SHF_INFO_LINK = 64;
-
-    public static final int SECTION_HDR_SIZE = 64;
-    abstract public static class Section {
-        String _name;
-        int _index;
-
-        int _type, _flags;
-        int _link, _info;
-
-        // where's the name in the string table
-        int _name_pos;
-        int _file_offset;
-
-        Section(String name, int type) {
-            _name = name;
-            _type = type;
-        }
-
-        void writeHeader(ByteBuffer out) {
-            out.putInt(_name_pos);     // name
-            out.putInt(_type);         // type
-            out.putLong(_flags);       // flags
-            out.putLong(0);            // addr
-            out.putLong(_file_offset); // offset
-            out.putLong(size());       // size
-            out.putInt(_link);         // link
-            out.putInt(_info);         // info
-            out.putLong(16);           // addralign
-            if (_type == 2) {
-                out.putLong(SYMBOL_SIZE);// entsize
-            } else if (_type == 4) {
-                out.putLong(24);         // entsize
-            } else {
-                out.putLong(0);          // entsize
-            }
-        }
-
-        abstract void write(ByteBuffer out);
-        abstract int size();
-    }
-
-    public static class SymbolSection extends Section {
-        Ary<Symbol> _symbols = new Ary<>(Symbol.class);
-        Ary<Symbol> _loc = new Ary<>(Symbol.class);
-
-        SymbolSection(String name, int type) {
-            super(name, type);
-        }
-
-        @Override
-        void writeHeader(ByteBuffer out) {
-            // points to string table section
-            _link = 1;
-
-            // number of non-local symbols
-            _info = _loc.len() + 1;
-
-            super.writeHeader(out);
-        }
-
-        void push(Symbol s) {
-            if ((s._info >> 4) != SYM_BIND_LOCAL) {
-                _symbols.push(s);
-            } else {
-                _loc.push(s);
-            }
-        }
-
-        @Override
-        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);
-            }
-            // index is already set
-            for( Symbol s : _loc ) {
-                s.writeHeader(out);
-            }
-            for( Symbol s : _symbols ) {
-                s.writeHeader(out);
-            }
-        }
-
-        @Override
-        int size() {
-            return (1 + _symbols.len() + _loc.len()) * SYMBOL_SIZE;
-        }
-    }
-
-    public static class DataSection extends Section {
-        ByteArrayOutputStream _contents;
-
-        DataSection(String name, int type) {
-            super(name, type);
-            _contents = new ByteArrayOutputStream();
-        }
-
-        DataSection(String name, int type, ByteArrayOutputStream contents) {
-            super(name, type);
-            _contents = contents;
-        }
-
-        @Override
-            void write(ByteBuffer out) {
-            out.put(_contents.toByteArray());
-        }
-
-        @Override
-            int size() {
-            return _contents.size();
-        }
-    }
-
-    private void pushSection(Section s) {
-        _sections.push(s);
-        // ELF is effectively "1-based", due to the NULL section
-        s._index = _sections._len;
-    }
-
-    /* creates function and stores where it starts*/
-    private final HashMap<TypeFunPtr,Symbol> _funcs = new HashMap<>();
-    private void encodeFunctions(SymbolSection symbols, DataSection text) {
-        for( int i=0; i<_code._cfg._len; i++ ) {
-            if( !(_code._cfg.at(i) instanceof FunNode fun) ) continue;
-            // skip until the function ends
-            while( !(_code._cfg.at(i) instanceof ReturnNode ret) )
-                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;
-            symbols.push(func);
-            _funcs.put(fun.sig(), func);
-        }
-    }
-
-    public void export(String fname) throws IOException {
-        DataSection strtab = new DataSection(".strtab", 3 /* SHT_SYMTAB */);
-        // first byte is reserved for an empty string
-        strtab._contents.write(0);
-        pushSection(strtab);
-
-        // place all the symbols
-        SymbolSection symbols = new SymbolSection(".symtab", 2 /* SHT_STRTAB */);
-        pushSection(symbols);
-
-        // zero flag by default
-        // we've already constructed this entire section in the encoding phase
-        DataSection text = new DataSection(".text", 1 /* SHT_PROGBITS */, _code._encoding._bits);
-        text._flags = SHF_ALLOC | SHF_WRITE | SHF_EXECINSTR;
-        pushSection(text);
-
-        // Build and write constant pool
-        BAOS cpool = new BAOS();
-        Encoding enc = _code._encoding;
-        enc.writeConstantPool(cpool,false);
-        DataSection rdata = new DataSection(".rodata", 1 /* SHT_PROGBITS */, cpool);
-        rdata._flags = SHF_ALLOC;
-        pushSection(rdata);
-
-        // populate function symbols
-        encodeFunctions(symbols, text);
-
-        int idx = 1;
-        for( Section s : _sections ) {
-            Symbol sym = new Symbol(s._name, idx++, SYM_BIND_LOCAL, SYM_TYPE_SECTION);
-            // we can reuse the same name pos from the actual section
-            sym._name_pos = s._name_pos;
-            sym._size = s.size();
-            symbols.push(sym);
-        }
-
-        // calculate local index
-        int num = 1;
-        for( Symbol s : symbols._loc )
-            s._index = num++;
-        // extra space for .rela.text
-        int start_global = num+1; // Add one to skip the final .rela.text local symbol
-        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 : enc._externals.keySet()) {
-            int nid    = n._nid;
-            String extern = enc._externals.get(n);
-
-            Symbol sym = new Symbol(extern, 0, SYM_BIND_GLOBAL, SYM_TYPE_NOTYPE);
-            sym._index = start_global++;
-            symbols.push(sym);
-
-            int offset = enc._opStart[nid] + enc._opLen[nid] - 4;
-
-            // u64 offset
-            write8(text_rela._contents, offset);
-            // u64 info
-            write8(text_rela._contents, ((long)sym._index << 32L) | 4L /* PLT32 */);
-            // i64 addend
-            write8(text_rela._contents, -4);
-        }
-
-        // Write relocations for the constant pool
-        for( Encoding.Relo relo : enc._bigCons.values() ) {
-            Symbol glob = new Symbol("CPOOL$"+start_global, rdata._index, SYM_BIND_GLOBAL, SYM_TYPE_FUNC);
-            glob._value = relo._target;
-            glob._size = relo._t.size();
-            glob._index = start_global++;
-            symbols.push(glob);
-            write8(text_rela._contents, relo._opStart+relo._off);
-            write8(text_rela._contents, ((long)glob._index << 32L) | relo._elf );
-            write8(text_rela._contents, -4);
-        }
-
-        text_rela._flags = SHF_INFO_LINK;
-        text_rela._link = 2;
-        text_rela._info = text._index;
-        pushSection(text_rela);
-
-        // Final .rela.text symbol
-        Symbol sym = new Symbol(text_rela._name, num++, SYM_BIND_LOCAL, SYM_TYPE_SECTION);
-        sym._name_pos = text_rela._name_pos;
-        sym._size = text_rela.size();
-        symbols.push(sym);
-
-        // populate string table
-        for( Section s : _sections ) { s._name_pos = writeCString(strtab, s._name); }
-        for( Symbol s : symbols._symbols ) { s._name_pos = writeCString(strtab, s._name); }
-        for( Symbol s : symbols._loc ) { s._name_pos = writeCString(strtab, s._name); }
-
-        int size = 64; // ELF header
-        // size of all section data
-        for( Section s : _sections ) {
-            s._file_offset = size;
-            size += s.size();
-        }
-        // headers go at the very end
-        int shdr_offset = size;
-        // there's a "null" section at the start of the section headers
-        size += SECTION_HDR_SIZE*(1 + _sections.len());
-
-        // System.out.printf("Hello %d, %d, %s\n", size, shdr_offset);
-        ByteBuffer out = ByteBuffer.allocate(size);
-        out.order(ByteOrder.LITTLE_ENDIAN);
-
-        // ELF header
-        out.put(new byte[]{ 0x7F, 'E', 'L', 'F', 2, 1, 1, 0 });
-        out.put(new byte[8]);
-        out.putShort((short)1 /* ET_REL */); // type
-        out.putShort((short)62 /* AMD64 */); // machine
-        out.putInt(1);                // version
-        out.putLong(0);               // entry
-        out.putLong(0);               // phoff
-        out.putLong(shdr_offset);     // shoff
-        out.putInt(0);                // flags
-        out.putShort((short)64);      // ehsize
-        out.putShort((short)0);       // phentsize
-        out.putShort((short)0);       // phnum
-        out.putShort((short)64);      // shentsize
-        out.putShort((short) (1 + _sections.len())); // shnum
-        out.putShort((short)1);       // shstrndx
-
-        // raw section data
-        for( Section s : _sections ) {
-            s.write(out);
-        }
-
-        // "null" section
-        for( int i = 0; i < 16; i++ ) {
-            out.putInt(0);
-        }
-
-        for( Section s : _sections ) {
-            s.writeHeader(out);
-        }
-        assert out.position() == size;
-
-        File file = new File(fname);
-        if( file.getParentFile()!=null )
-          file.getParentFile().mkdirs();
-        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
-        bos.write(out.array());
-        bos.close();
-    }
-
-}