* net/loveruby/cflat/compiler/CodeGenerator.java: remove unused labels.

* net/loveruby/cflat/asm/AsmStatistics.java: collect label usage.
* net/loveruby/cflat/asm/DirectMemoryReference.java: support collectStatistics.
* net/loveruby/cflat/asm/Literal.java: ditto.
* net/loveruby/cflat/asm/LabelRef.java: ditto.
* net/loveruby/cflat/asm/IntegerLiteral.java: ditto.


git-svn-id: file:///Users/aamine/c/gitwork/public/cbc/trunk@4054 1b9489fe-b721-0410-924e-b54b9192deb8

ChangeLog

@@ -1,3 +1,19 @@
+Wed Sep 24 01:10:36 2008  Minero Aoki  <aamine@loveruby.net>
+
+	* net/loveruby/cflat/compiler/CodeGenerator.java: remove unused
+	  labels.
+
+	* net/loveruby/cflat/asm/AsmStatistics.java: collect label usage.
+
+	* net/loveruby/cflat/asm/DirectMemoryReference.java: support
+	  collectStatistics.
+
+	* net/loveruby/cflat/asm/Literal.java: ditto.
+
+	* net/loveruby/cflat/asm/LabelRef.java: ditto.
+
+	* net/loveruby/cflat/asm/IntegerLiteral.java: ditto.
+
 Wed Sep 24 00:48:37 2008  Minero Aoki  <aamine@loveruby.net>
 
 	* net/loveruby/cflat/asm/PeepholeOptimizer.java: unify insn

ToDo

@@ -3,9 +3,6 @@
 == Current
 
 * check composite Type#equals, #hashCode (?)
-* -O (jump elimination)
-        * label renaming
-        * remove useless jump
 * Label -> Symbol
 * all Symbols should be got from objects
 * named/unnamed Label
@@ -252,3 +249,5 @@
 - generate prologue/epilogue after function body.
 - -O (fast immediate load)
 - check "puts = str"
+- -O (jump elimination)
+- useless label elimination

net/loveruby/cflat/asm/AsmStatistics.java

@@ -2,8 +2,9 @@ package net.loveruby.cflat.asm;
 import java.util.*;
 
 public class AsmStatistics {
-    protected Map registerUsage;
-    protected Map insnUsage;
+    protected Map registerUsage;   // Map<Register, Integer>
+    protected Map insnUsage;       // Map<String, Integer>
+    protected Map labelUsage;      // Map<Label, Integer>
 
     static public AsmStatistics collect(List assemblies) {
         AsmStatistics stats = new AsmStatistics();
@@ -18,13 +19,14 @@ public class AsmStatistics {
     public AsmStatistics() {
         registerUsage = new HashMap();
         insnUsage = new HashMap();
+        labelUsage = new HashMap();
     }
 
     public boolean doesRegisterUsed(Register reg) {
-        return numRegisterUsage(reg) > 0;
+        return numRegisterUsed(reg) > 0;
     }
 
-    public int numRegisterUsage(Register reg) {
+    public int numRegisterUsed(Register reg) {
         return fetchCount(registerUsage, reg);
     }
 
@@ -40,6 +42,18 @@ public class AsmStatistics {
         incrementCount(insnUsage, insn);
     }
 
+    public boolean doesLabelUsed(Label label) {
+        return numLabelUsed(label) > 0;
+    }
+
+    public int numLabelUsed(Label label) {
+        return fetchCount(labelUsage, label);
+    }
+
+    public void labelUsed(Label label) {
+        incrementCount(labelUsage, label);
+    }
+
     protected int fetchCount(Map m, Object key) {
         Integer n = (Integer)m.get(key);
         if (n == null) {

net/loveruby/cflat/asm/DirectMemoryReference.java

@@ -16,7 +16,7 @@ public class DirectMemoryReference extends MemoryReference {
     }
 
     public void collectStatistics(AsmStatistics stats) {
-        // does nothing
+        value.collectStatistics(stats);
     }
 
     public String toSource() {

net/loveruby/cflat/asm/IntegerLiteral.java

@@ -21,6 +21,10 @@ public class IntegerLiteral extends Literal {
         return this;
     }
 
+    public void collectStatistics(AsmStatistics stats) {
+        // does nothing
+    }
+
     public String toSource() {
         return new Long(value).toString();
     }

net/loveruby/cflat/asm/LabelRef.java

@@ -15,6 +15,10 @@ public class LabelRef extends Literal {
         return label.name();
     }
 
+    public void collectStatistics(AsmStatistics stats) {
+        stats.labelUsed(label);
+    }
+
     public String toSource() {
         return symbol();
     }

net/loveruby/cflat/asm/Literal.java

@@ -2,4 +2,5 @@ package net.loveruby.cflat.asm;
 
 abstract public class Literal {
     abstract public String toSource();
+    abstract public void collectStatistics(AsmStatistics stats);
 }

net/loveruby/cflat/compiler/CodeGenerator.java

@@ -217,6 +217,7 @@ public class CodeGenerator extends Visitor implements ASTLHSVisitor {
     protected void compileFunctionBody(DefinedFunction func) {
         List bodyAsms = compileStmts(func);
         AsmStatistics stats = AsmStatistics.collect(bodyAsms);
+        bodyAsms = reduceLabels(bodyAsms, stats);
         List saveRegs = usedCalleeSavedRegisters(stats);
         long lvarBytes = allocateLocalVariables(func.body().scope(),
                                                 saveRegs.size());
@@ -234,6 +235,21 @@ public class CodeGenerator extends Visitor implements ASTLHSVisitor {
         return optimizer.optimize(popAssembler().assemblies());
     }
 
+    protected List reduceLabels(List assemblies, AsmStatistics stats) {
+        List result = new ArrayList();
+        Iterator asms = assemblies.iterator();
+        while (asms.hasNext()) {
+            Assembly asm = (Assembly)asms.next();
+            if (asm.isLabel() && ! stats.doesLabelUsed((Label)asm)) {
+                ;
+            }
+            else {
+                result.add(asm);
+            }
+        }
+        return result;
+    }
+
     // #@@range/compile{
     protected void compile(Node n) {
         if (verboseAsm) {