1 files changed, 143 insertions, 0 deletions
diff --git a/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/peephole/UnreachableCodeRemover.java b/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/peephole/UnreachableCodeRemover.java
new file mode 100644
index 0000000000..aa07d11882
--- /dev/null
+++ b/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/peephole/UnreachableCodeRemover.java
@@ -0,0 +1,143 @@
+/*
+ * ProGuard -- shrinking, optimization, obfuscation, and preverification
+ *             of Java bytecode.
+ *
+ * Copyright (c) 2002-2017 Eric Lafortune @ GuardSquare
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+package proguard.optimize.peephole;
+
+import proguard.classfile.*;
+import proguard.classfile.attribute.*;
+import proguard.classfile.attribute.visitor.AttributeVisitor;
+import proguard.classfile.editor.CodeAttributeEditor;
+import proguard.classfile.instruction.Instruction;
+import proguard.classfile.instruction.visitor.InstructionVisitor;
+import proguard.classfile.util.SimplifiedVisitor;
+
+/**
+ * This InstructionVisitor deletes blocks of code that can never be reached by
+ * regular calls or branches.
+ *
+ * @author Eric Lafortune
+ */
+public class UnreachableCodeRemover
+extends      SimplifiedVisitor
+implements   AttributeVisitor,
+             InstructionVisitor
+{
+    //*
+    private static final boolean DEBUG = false;
+    /*/
+    private static       boolean DEBUG = true;
+    //*/
+
+    private final InstructionVisitor  extraInstructionVisitor;
+
+    private final ReachableCodeMarker reachableCodeMarker = new ReachableCodeMarker();
+    private final CodeAttributeEditor codeAttributeEditor = new CodeAttributeEditor();
+
+
+    /**
+     * Creates a new UnreachableCodeRemover.
+     */
+    public UnreachableCodeRemover()
+    {
+        this(null);
+    }
+
+
+    /**
+     * Creates a new UnreachableCodeRemover.
+     * @param extraInstructionVisitor an optional extra visitor for all
+     *                                deleted instructions.
+     */
+    public UnreachableCodeRemover(InstructionVisitor  extraInstructionVisitor)
+    {
+        this.extraInstructionVisitor = extraInstructionVisitor;
+    }
+
+
+    // Implementations for AttributeVisitor.
+
+    public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
+
+
+    public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute)
+    {
+//        DEBUG =
+//            clazz.getName().equals("abc/Def") &&
+//            method.getName(clazz).equals("abc");
+
+        // TODO: Remove this when the code has stabilized.
+        // Catch any unexpected exceptions from the actual visiting method.
+        try
+        {
+            // Process the code.
+            visitCodeAttribute0(clazz, method, codeAttribute);
+        }
+        catch (RuntimeException ex)
+        {
+            System.err.println("Unexpected error while removing unreachable code:");
+            System.err.println("  Class       = ["+clazz.getName()+"]");
+            System.err.println("  Method      = ["+method.getName(clazz)+method.getDescriptor(clazz)+"]");
+            System.err.println("  Exception   = ["+ex.getClass().getName()+"] ("+ex.getMessage()+")");
+
+            throw ex;
+        }
+    }
+
+
+    public void visitCodeAttribute0(Clazz clazz, Method method, CodeAttribute codeAttribute)
+    {
+        if (DEBUG)
+        {
+            System.out.println("UnreachableCodeRemover: "+clazz.getName()+"."+method.getName(clazz)+method.getDescriptor(clazz));
+        }
+
+        reachableCodeMarker.visitCodeAttribute(clazz, method, codeAttribute);
+
+        codeAttributeEditor.reset(codeAttribute.u4codeLength);
+
+        codeAttribute.instructionsAccept(clazz, method, this);
+
+        codeAttributeEditor.visitCodeAttribute(clazz, method, codeAttribute);
+    }
+
+
+    // Implementations for InstructionVisitor.
+
+    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction)
+    {
+        if (DEBUG)
+        {
+            System.out.println("  "+(reachableCodeMarker.isReachable(offset) ? "+" : "-")+" "+instruction.toString(offset));
+        }
+
+        // Is this instruction unreachable?
+        if (!reachableCodeMarker.isReachable(offset))
+        {
+            // Then delete it.
+            codeAttributeEditor.deleteInstruction(offset);
+
+            // Visit the instruction, if required.
+            if (extraInstructionVisitor != null)
+            {
+                instruction.accept(clazz, method, codeAttribute, offset, extraInstructionVisitor);
+            }
+        }
+    }
+}