Fix elf constants

Record more relocation info in the machine-specific encodings.  Use it when building ELF.
Switch to simpler Newtons; some encoding bug in the complex one.

7 files changed, 60 insertions, 75 deletions

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 62bcfcde..746ecfed 100644
--- a/chapter21/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java
+++ b/chapter21/src/main/java/com/seaofnodes/simple/codegen/ElfFile.java
@@ -8,6 +8,7 @@ import java.io.*;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.util.HashMap;
+import java.util.Map;
 
 public class ElfFile {
 
@@ -228,30 +229,6 @@ public class ElfFile {
         }
     }
 
-    public final HashMap<Type, Symbol> _bigCons = new HashMap<>();
-    private void encodeConstants(SymbolSection symbols, DataSection rdata) {
-        int cnt = 0;
-        for (Map.Entry<Node,Type> e : _code._encoding._bigCons.entrySet()) {
-            if (_bigCons.get(e.getValue()) != null) {
-                continue;
-            }
-
-            Symbol glob = new Symbol("GLOB$"+cnt, rdata._index, SYM_BIND_GLOBAL, SYM_TYPE_FUNC);
-            glob._value = rdata._contents.size();
-            symbols.push(glob);
-
-            Type t = e.getValue();
-            if ( t instanceof TypeFloat tf ) {
-                write8(rdata._contents, Double.doubleToLongBits(tf._con));
-            } else {
-                throw Utils.TODO();
-            }
-
-            glob._size = rdata._contents.size() - glob._value;
-            _bigCons.put(e.getValue(), glob);
-            cnt++;
-        }
-    }
     public void export(String fname) throws IOException {
         DataSection strtab = new DataSection(".strtab", 3 /* SHT_SYMTAB */);
         // first byte is reserved for an empty string
@@ -270,15 +247,14 @@ public class ElfFile {
 
         // Build and write constant pool
         BAOS cpool = new BAOS();
-        _code._encoding.writeConstantPool(cpool,false);
+        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);
-        // populate big constants
-        encodeConstants(symbols, rdata);
 
         int idx = 1;
         for( Section s : _sections ) {
@@ -294,21 +270,23 @@ public class ElfFile {
         for( Symbol s : symbols._loc )
             s._index = num++;
         // extra space for .rela.text
-        int start_global = symbols._loc.size();
-        for(Symbol a: symbols._symbols) {
+        int start_global = num+1; // Add one to skip the final .rela.text local symbol
+        for( Symbol a: symbols._symbols )
             a._index = start_global++;
+        int bigConIdx = start_global;
+        start_global += enc._bigCons.size();
 
         // create .text relocations
         DataSection text_rela = new DataSection(".rela.text", 4 /* SHT_RELA */);
-        for( Node n : _code._encoding._externals.keySet()) {
+        for( Node n : enc._externals.keySet()) {
             int nid    = n._nid;
-            String extern = _code._encoding._externals.get(n);
+            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 = _code._encoding._opStart[nid] + _code._encoding._opLen[nid] - 4;
+            int offset = enc._opStart[nid] + enc._opLen[nid] - 4;
 
             // u64 offset
             write8(text_rela._contents, offset);
@@ -318,17 +296,15 @@ public class ElfFile {
             write8(text_rela._contents, -4);
         }
 
-        // relocations to constants
-        for (Map.Entry<Node,Type> e : _code._encoding._bigCons.entrySet()) {
-            int nid    = e.getKey()._nid;
-            int sym_id = _bigCons.get(e.getValue())._index;
-            int offset = _code._encoding._opStart[nid] + _code._encoding._opLen[nid] - 4;
-
-            // u64 offset
-            write8(text_rela._contents, offset);
-            // u64 info
-            write8(text_rela._contents, ((long)sym_id << 32L) | 2L /* PC32 */);
-            // i64 addend
+        // Write relocations for the constant pool
+        for( Encoding.Relo relo : enc._bigCons.values() ) {
+            Symbol glob = new Symbol("GLOB$"+bigConIdx, rdata._index, SYM_BIND_GLOBAL, SYM_TYPE_FUNC);
+            glob._value = relo._target;
+            glob._size = 1 << relo._t.log_size();
+            glob._index = bigConIdx++;
+            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);
         }
 
@@ -337,7 +313,7 @@ public class ElfFile {
         text_rela._info = text._index;
         pushSection(text_rela);
 
-        Symbol sym = new Symbol(text_rela._name, num, SYM_BIND_LOCAL, SYM_TYPE_SECTION);
+        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);
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 f90ce96a..a66fc579 100644
--- a/chapter21/src/main/java/com/seaofnodes/simple/codegen/Encoding.java
+++ b/chapter21/src/main/java/com/seaofnodes/simple/codegen/Encoding.java
@@ -44,8 +44,19 @@ 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<>();
+    // Big Constant relocation info.
+    public static class Relo {
+        public final Node _op;
+        public final Type _t;          // Constant type
+        public final byte _off;        // Offset from start of opcode
+        public final byte _elf;        // ELF relocation type, e.g. 2/PC32
+        public int _target;      // Where constant is finally placede
+        public int _opStart;     // Opcode start
+        Relo( Node op, Type t, byte off, byte elf ) {
+            _op=op;  _t=t;  _off=off; _elf=elf;
+        }
+    }
+    public final HashMap<Node,Relo> _bigCons = new HashMap<>();
 
     Encoding( CodeGen code ) { _code = code; }
 
@@ -135,9 +146,11 @@ public class Encoding {
 
     // Store t as a 32/64 bit constant in the code space; generate RIP-relative
     // addressing to load it
-    public void largeConstant( Node relo, Type t ) {
+    public void largeConstant( Node relo, Type t, int off, int elf ) {
         assert t.isConstant();
-        _bigCons.put(relo,t);
+        assert (byte)off == off;
+        assert (byte)elf == elf;
+        _bigCons.put(relo,new Relo(relo,t,(byte)off,(byte)elf));
     }
 
     void encode() {
@@ -151,14 +164,13 @@ public class Encoding {
         // Record opcode start and length.
         writeEncodings();
 
-        // ELF handles big constants, they
-        // are accessed by RIP-relative addressing.
-
-        if(_code._JIT) writeConstantPool(true);
         // Short-form RIP-relative support: replace long encodings with short
         // encodings and compact the code, changing all the offsets.
         compactShortForm();
 
+        // Patch RIP-relative and local encodings now.
+        patchLocalRelocations();
+
     }
 
     // Basic block layout: invert branches to keep blocks in-order; insert
@@ -364,8 +376,8 @@ public class Encoding {
 
     // 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() ) {
+        HashSet<Relo> ts = new HashSet<>();
+        for( Relo t : _bigCons.values() ) {
             if( ts.contains(t) )
                 throw Utils.TODO(); // Dup!  Compress!
             ts.add(t);
@@ -375,21 +387,21 @@ public class Encoding {
         // By log size
         for( int log = 3; log >= 0; log-- ) {
             // Write the 8-byte constants
-            for( Node relo : _bigCons.keySet() ) {
-                Type t = _bigCons.get(relo);
-                if( t.log_size()==log ) {
+            for( Node op : _bigCons.keySet() ) {
+                Relo relo = _bigCons.get(op);
+                if( relo._t.log_size()==log ) {
                     // 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);
-                    }
+                    relo._target = bits.size();
+                    relo._opStart= _opStart[op._nid];
+                    // Go ahead and locally patch in-memory
+                    if( patch )
+                        ((RIPRelSize)op).patch(this, relo._opStart, _opLen[op._nid], relo._target - relo._opStart);
                     // Put constant into code space.
-                    if( t instanceof TypeTuple tt ) // Constant tuples put all entries
+                    if( relo._t instanceof TypeTuple tt ) // Constant tuples put all entries
                         for( Type tx : tt._types )
                             addN(log,tx,bits);
                     else
-                        addN(log,t,bits);
+                        addN(log,relo._t,bits);
                 }
             }
         }
diff --git a/chapter21/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java b/chapter21/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java
index 35d2008a..07a5dd12 100644
--- a/chapter21/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java
+++ b/chapter21/src/main/java/com/seaofnodes/simple/codegen/LinkMem.java
@@ -10,9 +10,6 @@ public class LinkMem {
         // 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;
     }
 }
diff --git a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/arm/FloatARM.java b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/arm/FloatARM.java
index 45ecc430..dc125af2 100644
--- a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/arm/FloatARM.java
+++ b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/arm/FloatARM.java
@@ -18,7 +18,7 @@ public class FloatARM extends ConstantNode implements MachNode, RIPRelSize {
     @Override public FloatARM copy() { return new FloatARM(this); }
 
     @Override public void encoding( Encoding enc ) {
-        enc.largeConstant(this,_con);
+        enc.largeConstant(this,_con,0,-1/*TODO: ARM-style ELF patching*/);
         short dst = (short)(enc.reg(this) - arm.D_OFFSET);
         double d = ((TypeFloat)_con).value();
         long x = Double.doubleToRawLongBits(d);
diff --git a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java
index d1bd4a94..0a7b02e3 100644
--- a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java
+++ b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/riscv/FltRISC.java
@@ -16,7 +16,7 @@ public class FltRISC extends ConstantNode implements MachNode, RIPRelSize {
     @Override public FltRISC copy() { return new FltRISC(this); }
 
     @Override public void encoding( Encoding enc ) {
-        enc.largeConstant(this,_con);
+        enc.largeConstant(this,_con, 0, -1/*TODO: RISC5 style patching*/);
         short dst = (short)(enc.reg(this) - riscv.F_OFFSET);
         short tmp = (short)riscv.T6;
         // AUIPC dst,#hi20_constant_pool
diff --git a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java
index c9df7b99..e3b20003 100644
--- a/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java
+++ b/chapter21/src/main/java/com/seaofnodes/simple/node/cpus/x86_64_v2/FltX86.java
@@ -19,7 +19,6 @@ public class FltX86 extends ConstantNode implements MachNode, RIPRelSize{
         // F2 0F 10 /r MOVSD xmm1, m64
         _encSize = 1/*Fop*/+0/*REX*/+2/*op*/+1/*MODRM*/+4/*offset*/;
         short dst = (short)(enc.reg(this ) - x86_64_v2.XMM_OFFSET);
-        enc.largeConstant(this,_con);
         // Fopcode
         enc.add1(0xF2);
         // rex prefix must come next (REX.W is not set)
@@ -28,6 +27,7 @@ public class FltX86 extends ConstantNode implements MachNode, RIPRelSize{
         // hard-code rip here
         enc.add1(x86_64_v2.modrm(x86_64_v2.MOD.INDIRECT, dst, 0x05));
         enc.add4(0);
+        enc.largeConstant(this,_con,_encSize-4,2/*ELF encoding PC32*/);
     }
 
     // Delta is from opcode start
diff --git a/chapter21/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java b/chapter21/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java
index 2e475f13..c040d414 100644
--- a/chapter21/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java
+++ b/chapter21/src/main/java/com/seaofnodes/simple/print/ASMPrinter.java
@@ -29,11 +29,11 @@ public abstract class ASMPrinter {
             sb.p("--- Constant Pool ------").nl();
             // By log size
             for( int log = 3; log >= 0; log-- ) {
-                for( Node relo : enc._bigCons.keySet() ) {
-                    Type t = enc._bigCons.get(relo);
-                    if( t.log_size()==log ) {
+                for( Node op : enc._bigCons.keySet() ) {
+                    Encoding.Relo relo = enc._bigCons.get(op);
+                    if( relo._t.log_size()==log ) {
                         sb.hex2(iadr).p("  ");
-                        if( t instanceof TypeTuple tt ) {
+                        if( relo._t instanceof TypeTuple tt ) {
                             for( Type tx : tt._types ) {
                                 switch( log ) {
                                 case 0: sb.hex1(enc.read1(iadr)); break;
@@ -53,7 +53,7 @@ public abstract class ASMPrinter {
                             }
                             iadr += (1<<log);
                         }
-                        t.print(sb).nl();
+                        relo._t.print(sb).nl();
                     }
                 }
             }