1 files changed, 189 insertions, 0 deletions
diff --git a/java/java-analysis-impl/src/com/intellij/codeInspection/bytecodeAnalysis/asm/LiteAnalyzer.java b/java/java-analysis-impl/src/com/intellij/codeInspection/bytecodeAnalysis/asm/LiteAnalyzer.java
new file mode 100644
index 000000000000..22961208076b
--- /dev/null
+++ b/java/java-analysis-impl/src/com/intellij/codeInspection/bytecodeAnalysis/asm/LiteAnalyzer.java
@@ -0,0 +1,189 @@
+/*
+ * Copyright 2000-2014 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.intellij.codeInspection.bytecodeAnalysis.asm;
+
+import org.jetbrains.org.objectweb.asm.Opcodes;
+import org.jetbrains.org.objectweb.asm.Type;
+import org.jetbrains.org.objectweb.asm.tree.*;
+import org.jetbrains.org.objectweb.asm.tree.analysis.AnalyzerException;
+import org.jetbrains.org.objectweb.asm.tree.analysis.Frame;
+import org.jetbrains.org.objectweb.asm.tree.analysis.Interpreter;
+import org.jetbrains.org.objectweb.asm.tree.analysis.Value;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Specialized lite version of {@link org.objectweb.asm.tree.analysis.Analyzer}.
+ * No processing of Subroutines. May be used for methods without JSR/RET instructions.
+ *
+ * @author lambdamix
+ */
+public class LiteAnalyzer<V extends Value> implements Opcodes {
+
+  private final Interpreter<V> interpreter;
+
+  private Frame<V>[] frames;
+
+  private boolean[] queued;
+
+  private int[] queue;
+
+  private int top;
+
+  public LiteAnalyzer(final Interpreter<V> interpreter) {
+    this.interpreter = interpreter;
+  }
+
+  public Frame<V>[] analyze(final String owner, final MethodNode m) throws AnalyzerException {
+    if ((m.access & (ACC_ABSTRACT | ACC_NATIVE)) != 0 || m.instructions.size() == 0) {
+      frames = (Frame<V>[]) new Frame<?>[0];
+      return frames;
+    }
+    int n = m.instructions.size();
+    InsnList insns = m.instructions;
+    List<TryCatchBlockNode>[] handlers = (List<TryCatchBlockNode>[]) new List<?>[n];
+    frames = (Frame<V>[]) new Frame<?>[n];
+    queued = new boolean[n];
+    queue = new int[n];
+    top = 0;
+
+    // computes exception handlers for each instruction
+    for (int i = 0; i < m.tryCatchBlocks.size(); ++i) {
+      TryCatchBlockNode tcb = m.tryCatchBlocks.get(i);
+      int begin = insns.indexOf(tcb.start);
+      int end = insns.indexOf(tcb.end);
+      for (int j = begin; j < end; ++j) {
+        List<TryCatchBlockNode> insnHandlers = handlers[j];
+        if (insnHandlers == null) {
+          insnHandlers = new ArrayList<TryCatchBlockNode>();
+          handlers[j] = insnHandlers;
+        }
+        insnHandlers.add(tcb);
+      }
+    }
+
+    // initializes the data structures for the control flow analysis
+    Frame<V> current = new Frame<V>(m.maxLocals, m.maxStack);
+    Frame<V> handler = new Frame<V>(m.maxLocals, m.maxStack);
+    current.setReturn(interpreter.newValue(Type.getReturnType(m.desc)));
+    Type[] args = Type.getArgumentTypes(m.desc);
+    int local = 0;
+    if ((m.access & ACC_STATIC) == 0) {
+      Type ctype = Type.getObjectType(owner);
+      current.setLocal(local++, interpreter.newValue(ctype));
+    }
+    for (int i = 0; i < args.length; ++i) {
+      current.setLocal(local++, interpreter.newValue(args[i]));
+      if (args[i].getSize() == 2) {
+        current.setLocal(local++, interpreter.newValue(null));
+      }
+    }
+    while (local < m.maxLocals) {
+      current.setLocal(local++, interpreter.newValue(null));
+    }
+    merge(0, current);
+
+    // control flow analysis
+    while (top > 0) {
+      int insn = queue[--top];
+      Frame<V> f = frames[insn];
+      queued[insn] = false;
+
+      AbstractInsnNode insnNode = null;
+      try {
+        insnNode = m.instructions.get(insn);
+        int insnOpcode = insnNode.getOpcode();
+        int insnType = insnNode.getType();
+
+        if (insnType == AbstractInsnNode.LABEL || insnType == AbstractInsnNode.LINE || insnType == AbstractInsnNode.FRAME) {
+          merge(insn + 1, f);
+        } else {
+          current.init(f).execute(insnNode, interpreter);
+
+          if (insnNode instanceof JumpInsnNode) {
+            JumpInsnNode j = (JumpInsnNode) insnNode;
+            if (insnOpcode != GOTO && insnOpcode != JSR) {
+              merge(insn + 1, current);
+            }
+            int jump = insns.indexOf(j.label);
+            merge(jump, current);
+          } else if (insnNode instanceof LookupSwitchInsnNode) {
+            LookupSwitchInsnNode lsi = (LookupSwitchInsnNode) insnNode;
+            int jump = insns.indexOf(lsi.dflt);
+            merge(jump, current);
+            for (int j = 0; j < lsi.labels.size(); ++j) {
+              LabelNode label = lsi.labels.get(j);
+              jump = insns.indexOf(label);
+              merge(jump, current);
+            }
+          } else if (insnNode instanceof TableSwitchInsnNode) {
+            TableSwitchInsnNode tsi = (TableSwitchInsnNode) insnNode;
+            int jump = insns.indexOf(tsi.dflt);
+            merge(jump, current);
+            for (int j = 0; j < tsi.labels.size(); ++j) {
+              LabelNode label = tsi.labels.get(j);
+              jump = insns.indexOf(label);
+              merge(jump, current);
+            }
+          } else if (insnOpcode != ATHROW && (insnOpcode < IRETURN || insnOpcode > RETURN)) {
+            merge(insn + 1, current);
+          }
+        }
+
+        List<TryCatchBlockNode> insnHandlers = handlers[insn];
+        if (insnHandlers != null) {
+          for (int i = 0; i < insnHandlers.size(); ++i) {
+            TryCatchBlockNode tcb = insnHandlers.get(i);
+            int jump = insns.indexOf(tcb.handler);
+            handler.init(f);
+            handler.clearStack();
+            handler.push(interpreter.newValue(ASMUtils.THROWABLE_TYPE));
+            merge(jump, handler);
+          }
+        }
+      } catch (AnalyzerException e) {
+        throw new AnalyzerException(e.node, "Error at instruction "  + insn + ": " + e.getMessage(), e);
+      } catch (Exception e) {
+        throw new AnalyzerException(insnNode, "Error at instruction " + insn + ": " + e.getMessage(), e);
+      }
+    }
+
+    return frames;
+  }
+
+  public Frame<V>[] getFrames() {
+    return frames;
+  }
+
+  private void merge(final int insn, final Frame<V> frame) throws AnalyzerException {
+    Frame<V> oldFrame = frames[insn];
+    boolean changes;
+
+    if (oldFrame == null) {
+      frames[insn] = new Frame<V>(frame);
+      changes = true;
+    } else {
+      changes = oldFrame.merge(frame, interpreter);
+    }
+    if (changes && !queued[insn]) {
+      queued[insn] = true;
+      queue[top++] = insn;
+    }
+  }
+
+}
+