1 files changed, 133 insertions, 0 deletions
diff --git a/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/peephole/VariableShrinker.java b/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/peephole/VariableShrinker.java
new file mode 100644
index 0000000000..8f01954ddf
--- /dev/null
+++ b/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/peephole/VariableShrinker.java
@@ -0,0 +1,133 @@
+/*
+ * 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.VariableEditor;
+import proguard.classfile.util.*;
+import proguard.classfile.visitor.MemberVisitor;
+import proguard.optimize.*;
+import proguard.optimize.info.*;
+
+/**
+ * This MemberVisitor removes unused local variables from the code of the methods
+ * that it visits.
+ *
+ * @see ParameterUsageMarker
+ * @see MethodStaticizer
+ * @see MethodDescriptorShrinker
+ * @author Eric Lafortune
+ */
+public class VariableShrinker
+extends      SimplifiedVisitor
+implements   AttributeVisitor
+{
+    //*
+    private static final boolean DEBUG = false;
+    /*/
+    private static       boolean DEBUG = System.getProperty("vs") != null;
+    //*/
+
+
+    private final MemberVisitor extraVariableMemberVisitor;
+
+    private final VariableUsageMarker variableUsageMarker = new VariableUsageMarker();
+    private final VariableEditor      variableEditor      = new VariableEditor();
+
+
+    /**
+     * Creates a new VariableShrinker.
+     */
+    public VariableShrinker()
+    {
+        this(null);
+    }
+
+
+    /**
+     * Creates a new VariableShrinker with an extra visitor.
+     * @param extraVariableMemberVisitor an optional extra visitor for all
+     *                                   removed variables.
+     */
+    public VariableShrinker(MemberVisitor extraVariableMemberVisitor)
+    {
+        this.extraVariableMemberVisitor = extraVariableMemberVisitor;
+    }
+
+
+    // Implementations for AttributeVisitor.
+
+    public void visitAnyAttribute(Clazz clazz, Attribute attribute) {}
+
+
+    public void visitCodeAttribute(Clazz clazz, Method method, CodeAttribute codeAttribute)
+    {
+        if ((method.getAccessFlags() & ClassConstants.ACC_ABSTRACT) == 0)
+        {
+            // Compute the parameter size.
+            int parameterSize =
+                ClassUtil.internalMethodParameterSize(method.getDescriptor(clazz),
+                                                      method.getAccessFlags());
+
+            // Get the total size of the local variable frame.
+            int maxLocals = codeAttribute.u2maxLocals;
+
+            if (DEBUG)
+            {
+                System.out.println("VariableShrinker: "+clazz.getName()+"."+method.getName(clazz)+method.getDescriptor(clazz));
+                System.out.println("  Parameter size = " + parameterSize);
+                System.out.println("  Max locals     = " + maxLocals);
+            }
+
+            // Figure out the local variables that are used by the code.
+            variableUsageMarker.visitCodeAttribute(clazz, method, codeAttribute);
+
+            // Delete unused local variables from the local variable frame.
+            variableEditor.reset(maxLocals);
+
+            for (int variableIndex = parameterSize; variableIndex < maxLocals; variableIndex++)
+            {
+                // Is the variable not required?
+                if (!variableUsageMarker.isVariableUsed(variableIndex))
+                {
+                    if (DEBUG)
+                    {
+                        System.out.println("  Deleting local variable #"+variableIndex);
+                    }
+
+                    // Delete the unused variable.
+                    variableEditor.deleteVariable(variableIndex);
+
+                    // Visit the method, if required.
+                    if (extraVariableMemberVisitor != null)
+                    {
+                        method.accept(clazz, extraVariableMemberVisitor);
+                    }
+                }
+            }
+
+            // Shift all remaining parameters and variables in the byte code.
+            variableEditor.visitCodeAttribute(clazz, method, codeAttribute);
+        }
+    }
+}