1 files changed, 115 insertions, 0 deletions
diff --git a/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/info/NonEmptyStackReturnMarker.java b/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/info/NonEmptyStackReturnMarker.java
new file mode 100644
index 0000000000..12124126ca
--- /dev/null
+++ b/third_party/java/proguard/proguard5.3.3/src/proguard/optimize/info/NonEmptyStackReturnMarker.java
@@ -0,0 +1,115 @@
+/*
+ * 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.info;
+
+import proguard.classfile.*;
+import proguard.classfile.attribute.CodeAttribute;
+import proguard.classfile.attribute.visitor.StackSizeComputer;
+import proguard.classfile.instruction.*;
+import proguard.classfile.instruction.visitor.InstructionVisitor;
+import proguard.classfile.util.SimplifiedVisitor;
+
+/**
+ * This InstructionVisitor marks all methods that return with a non-empty stack
+ * (other than the return value).
+ *
+ * @author Eric Lafortune
+ */
+public class NonEmptyStackReturnMarker
+extends      SimplifiedVisitor
+implements   InstructionVisitor
+{
+    private final StackSizeComputer stackSizeComputer;
+
+
+    /**
+     * Creates a new NonEmptyStackReturnMarker
+     * @param stackSizeComputer the stack size computer that can return the
+     *                          stack sizes at the instructions that are
+     *                          visited.
+     */
+    public NonEmptyStackReturnMarker(StackSizeComputer stackSizeComputer)
+    {
+        this.stackSizeComputer = stackSizeComputer;
+    }
+
+
+    // Implementations for InstructionVisitor.
+
+    public void visitAnyInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, Instruction instruction) {}
+
+
+    public void visitSimpleInstruction(Clazz clazz, Method method, CodeAttribute codeAttribute, int offset, SimpleInstruction simpleInstruction)
+    {
+        switch (simpleInstruction.opcode)
+        {
+            case InstructionConstants.OP_LRETURN:
+            case InstructionConstants.OP_DRETURN:
+                markReturnWithNonEmptyStack(method, offset, 2);
+                break;
+
+            case InstructionConstants.OP_IRETURN:
+            case InstructionConstants.OP_FRETURN:
+            case InstructionConstants.OP_ARETURN:
+                markReturnWithNonEmptyStack(method, offset, 1);
+                break;
+
+            case InstructionConstants.OP_RETURN:
+                markReturnWithNonEmptyStack(method, offset, 0);
+                break;
+        }
+    }
+
+
+    // Small utility methods.
+
+    /**
+     * Marks the given method if the stack before the given instruction offset
+     * has a size larger than the given size.
+     */
+    private void markReturnWithNonEmptyStack(Method method,
+                                             int    offset,
+                                             int    stackSize)
+    {
+        if (!stackSizeComputer.isReachable(offset) ||
+            stackSizeComputer.getStackSizeBefore(offset) > stackSize)
+        {
+            setReturnsWithNonEmptyStack(method);
+        }
+    }
+
+
+    private static void setReturnsWithNonEmptyStack(Method method)
+    {
+        MethodOptimizationInfo info = MethodOptimizationInfo.getMethodOptimizationInfo(method);
+        if (info != null)
+        {
+            info.setReturnsWithNonEmptyStack();
+        }
+    }
+
+
+    public static boolean returnsWithNonEmptyStack(Method method)
+    {
+        MethodOptimizationInfo info = MethodOptimizationInfo.getMethodOptimizationInfo(method);
+        return info == null || info.returnsWithNonEmptyStack();
+    }
+}