From f26d8a21e6bcd7cc838cdaef03b4f8a29ceeb279 Mon Sep 17 00:00:00 2001
From: hoenicke <hoenicke@379699f6-c40d-0410-875b-85095c16579e>
Date: Fri, 1 Dec 2000 10:33:58 +0000
Subject: [PATCH] Calculate number of stack elements and local variables in
 prepareWriting. Removed setting of number of local variables from
 LocalOptimizer.

git-svn-id: https://svn.code.sf.net/p/jode/code/branches/branch_1_1@1275 379699f6-c40d-0410-875b-85095c16579e
---
 jode/jode/bytecode/BytecodeInfo.java.in       | 105 +++++++++++++++---
 .../obfuscator/modules/LocalOptimizer.java.in |   9 +-
 2 files changed, 89 insertions(+), 25 deletions(-)

diff --git a/jode/jode/bytecode/BytecodeInfo.java.in b/jode/jode/bytecode/BytecodeInfo.java.in
index d7a0169..b098753 100644
--- a/jode/jode/bytecode/BytecodeInfo.java.in
+++ b/jode/jode/bytecode/BytecodeInfo.java.in
@@ -25,6 +25,8 @@ import java.io.ByteArrayInputStream;
 import java.io.InputStream;
 import java.io.EOFException;
 import java.io.IOException;
+import java.util.BitSet;
+import java.util.Stack;
 import java.util.Vector;
 import java.util.Enumeration;
 import java.util.NoSuchElementException;
@@ -901,9 +903,61 @@ public class BytecodeInfo extends BinaryInfo implements Opcodes {
 	}
     }
 
+    private void calculateMaxStack() {
+	maxStack = 0;
+	int[] stackHeights = new int[instructions.getCodeLength()];
+	int[] poppush = new int[2];
+	Stack todo = new Stack();
+
+	for (int i=0; i < stackHeights.length; i++)
+	    stackHeights[i] = -1;
+
+	stackHeights[0] = 0;
+	todo.push(instructions.get(0));
+	while (!todo.isEmpty()) {
+	    Instruction instr = (Instruction) todo.pop();
+	    Instruction next = instr.getNextByAddr();
+	    Instruction[] succs = instr.getSuccs();
+	    int addr = instr.getAddr();
+	    instr.getStackPopPush(poppush);
+	    int sh = stackHeights[addr] - poppush[0] + poppush[1];
+// 	    System.err.println("Instr: "+instr.getDescription()+
+// 			       "; before: "+stackHeights[addr]+" after: "+sh);
+	    if (maxStack < sh)
+		maxStack = sh;
+	    if (instr.getOpcode() == opc_jsr) {
+		if (stackHeights[next.getAddr()] == -1) {
+		    stackHeights[next.getAddr()] = sh - 1;
+		    todo.push(next);
+		}
+		if (stackHeights[succs[0].getAddr()] == -1) {
+		    stackHeights[succs[0].getAddr()] = sh;
+		    todo.push(succs[0]);
+		}
+	    } else {
+		if (succs != null) {
+		    for (int i=0; i < succs.length; i++) {
+			if (stackHeights[succs[i].getAddr()] == -1) {
+			    stackHeights[succs[i].getAddr()] = sh;
+			    todo.push(succs[i]);
+			}
+		    }
+		}
+		if (!instr.doesAlwaysJump()
+		    && stackHeights[next.getAddr()] == -1) {
+		    stackHeights[next.getAddr()] = sh;
+		    todo.push(next);
+		}
+	    }
+	}
+// 	System.err.println("New maxStack: "+maxStack+" Locals: "+maxLocals);
+    }
+
     public void prepareWriting(GrowableConstantPool gcp) {
-	/* Recalculate addr, length and add all constants to gcp */
+	/* Recalculate addr, length, maxStack, maxLocals and add all
+	 * constants to gcp */
 	int addr = 0;
+	maxLocals = 0;
 	for (Iterator iter = instructions.iterator(); iter.hasNext(); ) {
 	    Instruction instr = (Instruction) iter.next();
 	    int opcode = instr.getOpcode();
@@ -957,22 +1011,44 @@ public class BytecodeInfo extends BinaryInfo implements Opcodes {
 		    length = 3;
 		else
 		    length = 6;
+		if (slot >= maxLocals)
+		    maxLocals = slot + 1;
 		break;
 	    }
-	    case opc_iload: case opc_lload: 
-	    case opc_fload: case opc_dload: case opc_aload:
-	    case opc_istore: case opc_lstore: 
-	    case opc_fstore: case opc_dstore: case opc_astore:
-		if (instr.getLocalSlot() < 4) {
+	    case opc_iload: case opc_fload: case opc_aload:
+	    case opc_istore: case opc_fstore: case opc_astore: {
+		int slot = instr.getLocalSlot();
+		if (slot < 4)
 		    length = 1;
-		    break;
-		}
-		/* fall through */
+		else if (slot < 256)
+		    length = 2;
+		else 
+		    length = 4;
+		if (slot >= maxLocals)
+		    maxLocals = slot + 1;
+		break;
+	    }
+	    case opc_lload: case opc_dload:
+	    case opc_lstore: case opc_dstore: {
+		int slot = instr.getLocalSlot();
+		if (slot < 4)
+		    length = 1;
+		else if (slot < 256)
+		    length = 2;
+		else 
+		    length = 4;
+		if (slot+1 >= maxLocals)
+		    maxLocals = slot + 2;
+		break;
+	    }
 	    case opc_ret: {
-		if (instr.getLocalSlot() < 256)
+		int slot = instr.getLocalSlot();
+		if (slot < 256)
 		    length = 2;
 		else 
 		    length = 4;
+		if (slot >= maxLocals)
+		    maxLocals = slot + 1;
 		break;
 	    } 
 	    case opc_lookupswitch: {
@@ -1092,6 +1168,7 @@ public class BytecodeInfo extends BinaryInfo implements Opcodes {
 	    addr += length;
 	}
 	instructions.setLastAddr(addr);
+	calculateMaxStack();
 	for (int i=0; i< exceptionHandlers.length; i++)
 	    if (exceptionHandlers[i].type != null)
 		gcp.putClassName(exceptionHandlers[i].type);
@@ -1483,14 +1560,6 @@ public class BytecodeInfo extends BinaryInfo implements Opcodes {
 	return lnt;
     }
 
-    public void setMaxStack(int ms) {
-        maxStack = ms;
-    }
-
-    public void setMaxLocals(int ml) {
-        maxLocals = ml;
-    }
-
     public void setExceptionHandlers(Handler[] handlers) {
         exceptionHandlers = handlers;
     }
diff --git a/jode/jode/obfuscator/modules/LocalOptimizer.java.in b/jode/jode/obfuscator/modules/LocalOptimizer.java.in
index cb776fc..bb1b0c0 100644
--- a/jode/jode/obfuscator/modules/LocalOptimizer.java.in
+++ b/jode/jode/obfuscator/modules/LocalOptimizer.java.in
@@ -657,17 +657,12 @@ public class LocalOptimizer implements Opcodes, CodeTransformer {
 	 */
 	distributeLocals(locals);
 
-	/* Update the instructions and calculate new maxlocals.
+	/* Update the instructions.
 	 */
-	maxlocals = paramLocals.length;
 	for (InstrInfo info = firstInfo; info != null; info = info.nextInfo) {
-	    if (info.local != null) {
-		if (info.local.newSlot+info.local.size > maxlocals)
-		    maxlocals = info.local.newSlot + info.local.size;
+	    if (info.local != null)
 		info.instr.setLocalSlot(info.local.newSlot);
-	    }
 	}
-	bc.setMaxLocals(maxlocals);
 
 	/* Update LocalVariableTable
 	 */