Java Code Examples for com.sun.org.apache.bcel.internal.Constants#RETURN

The following examples show how to use com.sun.org.apache.bcel.internal.Constants#RETURN . You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example 1
Source File: ReturnInstruction.java    From jdk1.8-source-analysis with Apache License 2.0 5 votes vote down vote up 
public Type getType() {
  switch(opcode) {
    case Constants.IRETURN: return Type.INT;
    case Constants.LRETURN: return Type.LONG;
    case Constants.FRETURN: return Type.FLOAT;
    case Constants.DRETURN: return Type.DOUBLE;
    case Constants.ARETURN: return Type.OBJECT;
    case Constants.RETURN:  return Type.VOID;

  default: // Never reached
    throw new ClassGenException("Unknown type " + opcode);
  }
}
Example 2
Source File: ReturnInstruction.java    From openjdk-8 with GNU General Public License v2.0 5 votes vote down vote up 
public Type getType() {
  switch(opcode) {
    case Constants.IRETURN: return Type.INT;
    case Constants.LRETURN: return Type.LONG;
    case Constants.FRETURN: return Type.FLOAT;
    case Constants.DRETURN: return Type.DOUBLE;
    case Constants.ARETURN: return Type.OBJECT;
    case Constants.RETURN:  return Type.VOID;

  default: // Never reached
    throw new ClassGenException("Unknown type " + opcode);
  }
}
Example 3
Source File: ReturnInstruction.java    From openjdk-8-source with GNU General Public License v2.0 5 votes vote down vote up 
public Type getType() {
  switch(opcode) {
    case Constants.IRETURN: return Type.INT;
    case Constants.LRETURN: return Type.LONG;
    case Constants.FRETURN: return Type.FLOAT;
    case Constants.DRETURN: return Type.DOUBLE;
    case Constants.ARETURN: return Type.OBJECT;
    case Constants.RETURN:  return Type.VOID;

  default: // Never reached
    throw new ClassGenException("Unknown type " + opcode);
  }
}
Example 4
Source File: ReturnInstruction.java    From hottub with GNU General Public License v2.0 5 votes vote down vote up 
public Type getType() {
  switch(opcode) {
    case Constants.IRETURN: return Type.INT;
    case Constants.LRETURN: return Type.LONG;
    case Constants.FRETURN: return Type.FLOAT;
    case Constants.DRETURN: return Type.DOUBLE;
    case Constants.ARETURN: return Type.OBJECT;
    case Constants.RETURN:  return Type.VOID;

  default: // Never reached
    throw new ClassGenException("Unknown type " + opcode);
  }
}
Example 5
Source File: ReturnInstruction.java    From openjdk-jdk9 with GNU General Public License v2.0 5 votes vote down vote up 
public Type getType() {
  switch(opcode) {
    case Constants.IRETURN: return Type.INT;
    case Constants.LRETURN: return Type.LONG;
    case Constants.FRETURN: return Type.FLOAT;
    case Constants.DRETURN: return Type.DOUBLE;
    case Constants.ARETURN: return Type.OBJECT;
    case Constants.RETURN:  return Type.VOID;

  default: // Never reached
    throw new ClassGenException("Unknown type " + opcode);
  }
}
Example 6
Source File: ReturnInstruction.java    From openjdk-jdk8u-backup with GNU General Public License v2.0 5 votes vote down vote up 
public Type getType() {
  switch(opcode) {
    case Constants.IRETURN: return Type.INT;
    case Constants.LRETURN: return Type.LONG;
    case Constants.FRETURN: return Type.FLOAT;
    case Constants.DRETURN: return Type.DOUBLE;
    case Constants.ARETURN: return Type.OBJECT;
    case Constants.RETURN:  return Type.VOID;

  default: // Never reached
    throw new ClassGenException("Unknown type " + opcode);
  }
}
Example 7
Source File: ReturnInstruction.java    From openjdk-jdk8u with GNU General Public License v2.0 5 votes vote down vote up 
public Type getType() {
  switch(opcode) {
    case Constants.IRETURN: return Type.INT;
    case Constants.LRETURN: return Type.LONG;
    case Constants.FRETURN: return Type.FLOAT;
    case Constants.DRETURN: return Type.DOUBLE;
    case Constants.ARETURN: return Type.OBJECT;
    case Constants.RETURN:  return Type.VOID;

  default: // Never reached
    throw new ClassGenException("Unknown type " + opcode);
  }
}
Example 8
Source File: ReturnInstruction.java    From JDKSourceCode1.8 with MIT License 5 votes vote down vote up 
public Type getType() {
  switch(opcode) {
    case Constants.IRETURN: return Type.INT;
    case Constants.LRETURN: return Type.LONG;
    case Constants.FRETURN: return Type.FLOAT;
    case Constants.DRETURN: return Type.DOUBLE;
    case Constants.ARETURN: return Type.OBJECT;
    case Constants.RETURN:  return Type.VOID;

  default: // Never reached
    throw new ClassGenException("Unknown type " + opcode);
  }
}
Example 9
Source File: ReturnInstruction.java    From jdk8u60 with GNU General Public License v2.0 5 votes vote down vote up 
public Type getType() {
  switch(opcode) {
    case Constants.IRETURN: return Type.INT;
    case Constants.LRETURN: return Type.LONG;
    case Constants.FRETURN: return Type.FLOAT;
    case Constants.DRETURN: return Type.DOUBLE;
    case Constants.ARETURN: return Type.OBJECT;
    case Constants.RETURN:  return Type.VOID;

  default: // Never reached
    throw new ClassGenException("Unknown type " + opcode);
  }
}
Example 10
Source File: ReturnInstruction.java    From TencentKona-8 with GNU General Public License v2.0 5 votes vote down vote up 
public Type getType() {
  switch(opcode) {
    case Constants.IRETURN: return Type.INT;
    case Constants.LRETURN: return Type.LONG;
    case Constants.FRETURN: return Type.FLOAT;
    case Constants.DRETURN: return Type.DOUBLE;
    case Constants.ARETURN: return Type.OBJECT;
    case Constants.RETURN:  return Type.VOID;

  default: // Never reached
    throw new ClassGenException("Unknown type " + opcode);
  }
}
Example 11
Source File: MethodGen.java    From openjdk-jdk8u with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Computes stack usage of an instruction list by performing control flow analysis.
 *
 * @return maximum stack depth used by method
 */
public static int getMaxStack(ConstantPoolGen cp, InstructionList il, CodeExceptionGen[] et) {
  BranchStack branchTargets = new BranchStack();

  /* Initially, populate the branch stack with the exception
   * handlers, because these aren't (necessarily) branched to
   * explicitly. in each case, the stack will have depth 1,
   * containing the exception object.
   */
  for (int i = 0; i < et.length; i++) {
    InstructionHandle handler_pc = et[i].getHandlerPC();
    if (handler_pc != null)
      branchTargets.push(handler_pc, 1);
  }

  int               stackDepth = 0, maxStackDepth = 0;
  InstructionHandle ih         = il.getStart();

  while(ih != null) {
    Instruction instruction = ih.getInstruction();
    short opcode = instruction.getOpcode();
    int delta = instruction.produceStack(cp) - instruction.consumeStack(cp);

    stackDepth += delta;
    if(stackDepth > maxStackDepth)
      maxStackDepth = stackDepth;

    // choose the next instruction based on whether current is a branch.
    if(instruction instanceof BranchInstruction) {
      BranchInstruction branch = (BranchInstruction) instruction;
      if(instruction instanceof Select) {
        // explore all of the select's targets. the default target is handled below.
        Select select = (Select) branch;
        InstructionHandle[] targets = select.getTargets();
        for (int i = 0; i < targets.length; i++)
          branchTargets.push(targets[i], stackDepth);
        // nothing to fall through to.
        ih = null;
      } else if(!(branch instanceof IfInstruction)) {
        // if an instruction that comes back to following PC,
        // push next instruction, with stack depth reduced by 1.
        if(opcode == Constants.JSR || opcode == Constants.JSR_W)
          branchTargets.push(ih.getNext(), stackDepth - 1);
        ih = null;
      }
      // for all branches, the target of the branch is pushed on the branch stack.
      // conditional branches have a fall through case, selects don't, and
      // jsr/jsr_w return to the next instruction.
      branchTargets.push(branch.getTarget(), stackDepth);
    } else {
      // check for instructions that terminate the method.
      if(opcode == Constants.ATHROW || opcode == Constants.RET ||
         (opcode >= Constants.IRETURN && opcode <= Constants.RETURN))
        ih = null;
    }
    // normal case, go to the next instruction.
    if(ih != null)
      ih = ih.getNext();
    // if we have no more instructions, see if there are any deferred branches to explore.
    if(ih == null) {
      BranchTarget bt = branchTargets.pop();
      if (bt != null) {
        ih = bt.target;
        stackDepth = bt.stackDepth;
      }
    }
  }

  return maxStackDepth;
}
Example 12
Source File: MethodGen.java    From JDKSourceCode1.8 with MIT License 4 votes vote down vote up 
/**
 * Computes stack usage of an instruction list by performing control flow analysis.
 *
 * @return maximum stack depth used by method
 */
public static int getMaxStack(ConstantPoolGen cp, InstructionList il, CodeExceptionGen[] et) {
  BranchStack branchTargets = new BranchStack();

  /* Initially, populate the branch stack with the exception
   * handlers, because these aren't (necessarily) branched to
   * explicitly. in each case, the stack will have depth 1,
   * containing the exception object.
   */
  for (int i = 0; i < et.length; i++) {
    InstructionHandle handler_pc = et[i].getHandlerPC();
    if (handler_pc != null)
      branchTargets.push(handler_pc, 1);
  }

  int               stackDepth = 0, maxStackDepth = 0;
  InstructionHandle ih         = il.getStart();

  while(ih != null) {
    Instruction instruction = ih.getInstruction();
    short opcode = instruction.getOpcode();
    int delta = instruction.produceStack(cp) - instruction.consumeStack(cp);

    stackDepth += delta;
    if(stackDepth > maxStackDepth)
      maxStackDepth = stackDepth;

    // choose the next instruction based on whether current is a branch.
    if(instruction instanceof BranchInstruction) {
      BranchInstruction branch = (BranchInstruction) instruction;
      if(instruction instanceof Select) {
        // explore all of the select's targets. the default target is handled below.
        Select select = (Select) branch;
        InstructionHandle[] targets = select.getTargets();
        for (int i = 0; i < targets.length; i++)
          branchTargets.push(targets[i], stackDepth);
        // nothing to fall through to.
        ih = null;
      } else if(!(branch instanceof IfInstruction)) {
        // if an instruction that comes back to following PC,
        // push next instruction, with stack depth reduced by 1.
        if(opcode == Constants.JSR || opcode == Constants.JSR_W)
          branchTargets.push(ih.getNext(), stackDepth - 1);
        ih = null;
      }
      // for all branches, the target of the branch is pushed on the branch stack.
      // conditional branches have a fall through case, selects don't, and
      // jsr/jsr_w return to the next instruction.
      branchTargets.push(branch.getTarget(), stackDepth);
    } else {
      // check for instructions that terminate the method.
      if(opcode == Constants.ATHROW || opcode == Constants.RET ||
         (opcode >= Constants.IRETURN && opcode <= Constants.RETURN))
        ih = null;
    }
    // normal case, go to the next instruction.
    if(ih != null)
      ih = ih.getNext();
    // if we have no more instructions, see if there are any deferred branches to explore.
    if(ih == null) {
      BranchTarget bt = branchTargets.pop();
      if (bt != null) {
        ih = bt.target;
        stackDepth = bt.stackDepth;
      }
    }
  }

  return maxStackDepth;
}
Example 13
Source File: MethodGen.java    From openjdk-jdk8u-backup with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Computes stack usage of an instruction list by performing control flow analysis.
 *
 * @return maximum stack depth used by method
 */
public static int getMaxStack(ConstantPoolGen cp, InstructionList il, CodeExceptionGen[] et) {
  BranchStack branchTargets = new BranchStack();

  /* Initially, populate the branch stack with the exception
   * handlers, because these aren't (necessarily) branched to
   * explicitly. in each case, the stack will have depth 1,
   * containing the exception object.
   */
  for (int i = 0; i < et.length; i++) {
    InstructionHandle handler_pc = et[i].getHandlerPC();
    if (handler_pc != null)
      branchTargets.push(handler_pc, 1);
  }

  int               stackDepth = 0, maxStackDepth = 0;
  InstructionHandle ih         = il.getStart();

  while(ih != null) {
    Instruction instruction = ih.getInstruction();
    short opcode = instruction.getOpcode();
    int delta = instruction.produceStack(cp) - instruction.consumeStack(cp);

    stackDepth += delta;
    if(stackDepth > maxStackDepth)
      maxStackDepth = stackDepth;

    // choose the next instruction based on whether current is a branch.
    if(instruction instanceof BranchInstruction) {
      BranchInstruction branch = (BranchInstruction) instruction;
      if(instruction instanceof Select) {
        // explore all of the select's targets. the default target is handled below.
        Select select = (Select) branch;
        InstructionHandle[] targets = select.getTargets();
        for (int i = 0; i < targets.length; i++)
          branchTargets.push(targets[i], stackDepth);
        // nothing to fall through to.
        ih = null;
      } else if(!(branch instanceof IfInstruction)) {
        // if an instruction that comes back to following PC,
        // push next instruction, with stack depth reduced by 1.
        if(opcode == Constants.JSR || opcode == Constants.JSR_W)
          branchTargets.push(ih.getNext(), stackDepth - 1);
        ih = null;
      }
      // for all branches, the target of the branch is pushed on the branch stack.
      // conditional branches have a fall through case, selects don't, and
      // jsr/jsr_w return to the next instruction.
      branchTargets.push(branch.getTarget(), stackDepth);
    } else {
      // check for instructions that terminate the method.
      if(opcode == Constants.ATHROW || opcode == Constants.RET ||
         (opcode >= Constants.IRETURN && opcode <= Constants.RETURN))
        ih = null;
    }
    // normal case, go to the next instruction.
    if(ih != null)
      ih = ih.getNext();
    // if we have no more instructions, see if there are any deferred branches to explore.
    if(ih == null) {
      BranchTarget bt = branchTargets.pop();
      if (bt != null) {
        ih = bt.target;
        stackDepth = bt.stackDepth;
      }
    }
  }

  return maxStackDepth;
}
Example 14
Source File: MethodGen.java    From openjdk-jdk9 with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Computes stack usage of an instruction list by performing control flow analysis.
 *
 * @return maximum stack depth used by method
 */
public static int getMaxStack(ConstantPoolGen cp, InstructionList il, CodeExceptionGen[] et) {
  BranchStack branchTargets = new BranchStack();

  /* Initially, populate the branch stack with the exception
   * handlers, because these aren't (necessarily) branched to
   * explicitly. in each case, the stack will have depth 1,
   * containing the exception object.
   */
  for (int i = 0; i < et.length; i++) {
    InstructionHandle handler_pc = et[i].getHandlerPC();
    if (handler_pc != null)
      branchTargets.push(handler_pc, 1);
  }

  int               stackDepth = 0, maxStackDepth = 0;
  InstructionHandle ih         = il.getStart();

  while(ih != null) {
    Instruction instruction = ih.getInstruction();
    short opcode = instruction.getOpcode();
    int delta = instruction.produceStack(cp) - instruction.consumeStack(cp);

    stackDepth += delta;
    if(stackDepth > maxStackDepth)
      maxStackDepth = stackDepth;

    // choose the next instruction based on whether current is a branch.
    if(instruction instanceof BranchInstruction) {
      BranchInstruction branch = (BranchInstruction) instruction;
      if(instruction instanceof Select) {
        // explore all of the select's targets. the default target is handled below.
        Select select = (Select) branch;
        InstructionHandle[] targets = select.getTargets();
        for (int i = 0; i < targets.length; i++)
          branchTargets.push(targets[i], stackDepth);
        // nothing to fall through to.
        ih = null;
      } else if(!(branch instanceof IfInstruction)) {
        // if an instruction that comes back to following PC,
        // push next instruction, with stack depth reduced by 1.
        if(opcode == Constants.JSR || opcode == Constants.JSR_W)
          branchTargets.push(ih.getNext(), stackDepth - 1);
        ih = null;
      }
      // for all branches, the target of the branch is pushed on the branch stack.
      // conditional branches have a fall through case, selects don't, and
      // jsr/jsr_w return to the next instruction.
      branchTargets.push(branch.getTarget(), stackDepth);
    } else {
      // check for instructions that terminate the method.
      if(opcode == Constants.ATHROW || opcode == Constants.RET ||
         (opcode >= Constants.IRETURN && opcode <= Constants.RETURN))
        ih = null;
    }
    // normal case, go to the next instruction.
    if(ih != null)
      ih = ih.getNext();
    // if we have no more instructions, see if there are any deferred branches to explore.
    if(ih == null) {
      BranchTarget bt = branchTargets.pop();
      if (bt != null) {
        ih = bt.target;
        stackDepth = bt.stackDepth;
      }
    }
  }

  return maxStackDepth;
}
Example 15
Source File: MethodGen.java    From jdk8u60 with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Computes stack usage of an instruction list by performing control flow analysis.
 *
 * @return maximum stack depth used by method
 */
public static int getMaxStack(ConstantPoolGen cp, InstructionList il, CodeExceptionGen[] et) {
  BranchStack branchTargets = new BranchStack();

  /* Initially, populate the branch stack with the exception
   * handlers, because these aren't (necessarily) branched to
   * explicitly. in each case, the stack will have depth 1,
   * containing the exception object.
   */
  for (int i = 0; i < et.length; i++) {
    InstructionHandle handler_pc = et[i].getHandlerPC();
    if (handler_pc != null)
      branchTargets.push(handler_pc, 1);
  }

  int               stackDepth = 0, maxStackDepth = 0;
  InstructionHandle ih         = il.getStart();

  while(ih != null) {
    Instruction instruction = ih.getInstruction();
    short opcode = instruction.getOpcode();
    int delta = instruction.produceStack(cp) - instruction.consumeStack(cp);

    stackDepth += delta;
    if(stackDepth > maxStackDepth)
      maxStackDepth = stackDepth;

    // choose the next instruction based on whether current is a branch.
    if(instruction instanceof BranchInstruction) {
      BranchInstruction branch = (BranchInstruction) instruction;
      if(instruction instanceof Select) {
        // explore all of the select's targets. the default target is handled below.
        Select select = (Select) branch;
        InstructionHandle[] targets = select.getTargets();
        for (int i = 0; i < targets.length; i++)
          branchTargets.push(targets[i], stackDepth);
        // nothing to fall through to.
        ih = null;
      } else if(!(branch instanceof IfInstruction)) {
        // if an instruction that comes back to following PC,
        // push next instruction, with stack depth reduced by 1.
        if(opcode == Constants.JSR || opcode == Constants.JSR_W)
          branchTargets.push(ih.getNext(), stackDepth - 1);
        ih = null;
      }
      // for all branches, the target of the branch is pushed on the branch stack.
      // conditional branches have a fall through case, selects don't, and
      // jsr/jsr_w return to the next instruction.
      branchTargets.push(branch.getTarget(), stackDepth);
    } else {
      // check for instructions that terminate the method.
      if(opcode == Constants.ATHROW || opcode == Constants.RET ||
         (opcode >= Constants.IRETURN && opcode <= Constants.RETURN))
        ih = null;
    }
    // normal case, go to the next instruction.
    if(ih != null)
      ih = ih.getNext();
    // if we have no more instructions, see if there are any deferred branches to explore.
    if(ih == null) {
      BranchTarget bt = branchTargets.pop();
      if (bt != null) {
        ih = bt.target;
        stackDepth = bt.stackDepth;
      }
    }
  }

  return maxStackDepth;
}
Example 16
Source File: MethodGen.java    From hottub with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Computes stack usage of an instruction list by performing control flow analysis.
 *
 * @return maximum stack depth used by method
 */
public static int getMaxStack(ConstantPoolGen cp, InstructionList il, CodeExceptionGen[] et) {
  BranchStack branchTargets = new BranchStack();

  /* Initially, populate the branch stack with the exception
   * handlers, because these aren't (necessarily) branched to
   * explicitly. in each case, the stack will have depth 1,
   * containing the exception object.
   */
  for (int i = 0; i < et.length; i++) {
    InstructionHandle handler_pc = et[i].getHandlerPC();
    if (handler_pc != null)
      branchTargets.push(handler_pc, 1);
  }

  int               stackDepth = 0, maxStackDepth = 0;
  InstructionHandle ih         = il.getStart();

  while(ih != null) {
    Instruction instruction = ih.getInstruction();
    short opcode = instruction.getOpcode();
    int delta = instruction.produceStack(cp) - instruction.consumeStack(cp);

    stackDepth += delta;
    if(stackDepth > maxStackDepth)
      maxStackDepth = stackDepth;

    // choose the next instruction based on whether current is a branch.
    if(instruction instanceof BranchInstruction) {
      BranchInstruction branch = (BranchInstruction) instruction;
      if(instruction instanceof Select) {
        // explore all of the select's targets. the default target is handled below.
        Select select = (Select) branch;
        InstructionHandle[] targets = select.getTargets();
        for (int i = 0; i < targets.length; i++)
          branchTargets.push(targets[i], stackDepth);
        // nothing to fall through to.
        ih = null;
      } else if(!(branch instanceof IfInstruction)) {
        // if an instruction that comes back to following PC,
        // push next instruction, with stack depth reduced by 1.
        if(opcode == Constants.JSR || opcode == Constants.JSR_W)
          branchTargets.push(ih.getNext(), stackDepth - 1);
        ih = null;
      }
      // for all branches, the target of the branch is pushed on the branch stack.
      // conditional branches have a fall through case, selects don't, and
      // jsr/jsr_w return to the next instruction.
      branchTargets.push(branch.getTarget(), stackDepth);
    } else {
      // check for instructions that terminate the method.
      if(opcode == Constants.ATHROW || opcode == Constants.RET ||
         (opcode >= Constants.IRETURN && opcode <= Constants.RETURN))
        ih = null;
    }
    // normal case, go to the next instruction.
    if(ih != null)
      ih = ih.getNext();
    // if we have no more instructions, see if there are any deferred branches to explore.
    if(ih == null) {
      BranchTarget bt = branchTargets.pop();
      if (bt != null) {
        ih = bt.target;
        stackDepth = bt.stackDepth;
      }
    }
  }

  return maxStackDepth;
}
Example 17
Source File: MethodGen.java    From openjdk-8-source with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Computes stack usage of an instruction list by performing control flow analysis.
 *
 * @return maximum stack depth used by method
 */
public static int getMaxStack(ConstantPoolGen cp, InstructionList il, CodeExceptionGen[] et) {
  BranchStack branchTargets = new BranchStack();

  /* Initially, populate the branch stack with the exception
   * handlers, because these aren't (necessarily) branched to
   * explicitly. in each case, the stack will have depth 1,
   * containing the exception object.
   */
  for (int i = 0; i < et.length; i++) {
    InstructionHandle handler_pc = et[i].getHandlerPC();
    if (handler_pc != null)
      branchTargets.push(handler_pc, 1);
  }

  int               stackDepth = 0, maxStackDepth = 0;
  InstructionHandle ih         = il.getStart();

  while(ih != null) {
    Instruction instruction = ih.getInstruction();
    short opcode = instruction.getOpcode();
    int delta = instruction.produceStack(cp) - instruction.consumeStack(cp);

    stackDepth += delta;
    if(stackDepth > maxStackDepth)
      maxStackDepth = stackDepth;

    // choose the next instruction based on whether current is a branch.
    if(instruction instanceof BranchInstruction) {
      BranchInstruction branch = (BranchInstruction) instruction;
      if(instruction instanceof Select) {
        // explore all of the select's targets. the default target is handled below.
        Select select = (Select) branch;
        InstructionHandle[] targets = select.getTargets();
        for (int i = 0; i < targets.length; i++)
          branchTargets.push(targets[i], stackDepth);
        // nothing to fall through to.
        ih = null;
      } else if(!(branch instanceof IfInstruction)) {
        // if an instruction that comes back to following PC,
        // push next instruction, with stack depth reduced by 1.
        if(opcode == Constants.JSR || opcode == Constants.JSR_W)
          branchTargets.push(ih.getNext(), stackDepth - 1);
        ih = null;
      }
      // for all branches, the target of the branch is pushed on the branch stack.
      // conditional branches have a fall through case, selects don't, and
      // jsr/jsr_w return to the next instruction.
      branchTargets.push(branch.getTarget(), stackDepth);
    } else {
      // check for instructions that terminate the method.
      if(opcode == Constants.ATHROW || opcode == Constants.RET ||
         (opcode >= Constants.IRETURN && opcode <= Constants.RETURN))
        ih = null;
    }
    // normal case, go to the next instruction.
    if(ih != null)
      ih = ih.getNext();
    // if we have no more instructions, see if there are any deferred branches to explore.
    if(ih == null) {
      BranchTarget bt = branchTargets.pop();
      if (bt != null) {
        ih = bt.target;
        stackDepth = bt.stackDepth;
      }
    }
  }

  return maxStackDepth;
}
Example 18
Source File: MethodGen.java    From TencentKona-8 with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Computes stack usage of an instruction list by performing control flow analysis.
 *
 * @return maximum stack depth used by method
 */
public static int getMaxStack(ConstantPoolGen cp, InstructionList il, CodeExceptionGen[] et) {
  BranchStack branchTargets = new BranchStack();

  /* Initially, populate the branch stack with the exception
   * handlers, because these aren't (necessarily) branched to
   * explicitly. in each case, the stack will have depth 1,
   * containing the exception object.
   */
  for (int i = 0; i < et.length; i++) {
    InstructionHandle handler_pc = et[i].getHandlerPC();
    if (handler_pc != null)
      branchTargets.push(handler_pc, 1);
  }

  int               stackDepth = 0, maxStackDepth = 0;
  InstructionHandle ih         = il.getStart();

  while(ih != null) {
    Instruction instruction = ih.getInstruction();
    short opcode = instruction.getOpcode();
    int delta = instruction.produceStack(cp) - instruction.consumeStack(cp);

    stackDepth += delta;
    if(stackDepth > maxStackDepth)
      maxStackDepth = stackDepth;

    // choose the next instruction based on whether current is a branch.
    if(instruction instanceof BranchInstruction) {
      BranchInstruction branch = (BranchInstruction) instruction;
      if(instruction instanceof Select) {
        // explore all of the select's targets. the default target is handled below.
        Select select = (Select) branch;
        InstructionHandle[] targets = select.getTargets();
        for (int i = 0; i < targets.length; i++)
          branchTargets.push(targets[i], stackDepth);
        // nothing to fall through to.
        ih = null;
      } else if(!(branch instanceof IfInstruction)) {
        // if an instruction that comes back to following PC,
        // push next instruction, with stack depth reduced by 1.
        if(opcode == Constants.JSR || opcode == Constants.JSR_W)
          branchTargets.push(ih.getNext(), stackDepth - 1);
        ih = null;
      }
      // for all branches, the target of the branch is pushed on the branch stack.
      // conditional branches have a fall through case, selects don't, and
      // jsr/jsr_w return to the next instruction.
      branchTargets.push(branch.getTarget(), stackDepth);
    } else {
      // check for instructions that terminate the method.
      if(opcode == Constants.ATHROW || opcode == Constants.RET ||
         (opcode >= Constants.IRETURN && opcode <= Constants.RETURN))
        ih = null;
    }
    // normal case, go to the next instruction.
    if(ih != null)
      ih = ih.getNext();
    // if we have no more instructions, see if there are any deferred branches to explore.
    if(ih == null) {
      BranchTarget bt = branchTargets.pop();
      if (bt != null) {
        ih = bt.target;
        stackDepth = bt.stackDepth;
      }
    }
  }

  return maxStackDepth;
}
Example 19
Source File: MethodGen.java    From openjdk-8 with GNU General Public License v2.0 4 votes vote down vote up 
/**
 * Computes stack usage of an instruction list by performing control flow analysis.
 *
 * @return maximum stack depth used by method
 */
public static int getMaxStack(ConstantPoolGen cp, InstructionList il, CodeExceptionGen[] et) {
  BranchStack branchTargets = new BranchStack();

  /* Initially, populate the branch stack with the exception
   * handlers, because these aren't (necessarily) branched to
   * explicitly. in each case, the stack will have depth 1,
   * containing the exception object.
   */
  for (int i = 0; i < et.length; i++) {
    InstructionHandle handler_pc = et[i].getHandlerPC();
    if (handler_pc != null)
      branchTargets.push(handler_pc, 1);
  }

  int               stackDepth = 0, maxStackDepth = 0;
  InstructionHandle ih         = il.getStart();

  while(ih != null) {
    Instruction instruction = ih.getInstruction();
    short opcode = instruction.getOpcode();
    int delta = instruction.produceStack(cp) - instruction.consumeStack(cp);

    stackDepth += delta;
    if(stackDepth > maxStackDepth)
      maxStackDepth = stackDepth;

    // choose the next instruction based on whether current is a branch.
    if(instruction instanceof BranchInstruction) {
      BranchInstruction branch = (BranchInstruction) instruction;
      if(instruction instanceof Select) {
        // explore all of the select's targets. the default target is handled below.
        Select select = (Select) branch;
        InstructionHandle[] targets = select.getTargets();
        for (int i = 0; i < targets.length; i++)
          branchTargets.push(targets[i], stackDepth);
        // nothing to fall through to.
        ih = null;
      } else if(!(branch instanceof IfInstruction)) {
        // if an instruction that comes back to following PC,
        // push next instruction, with stack depth reduced by 1.
        if(opcode == Constants.JSR || opcode == Constants.JSR_W)
          branchTargets.push(ih.getNext(), stackDepth - 1);
        ih = null;
      }
      // for all branches, the target of the branch is pushed on the branch stack.
      // conditional branches have a fall through case, selects don't, and
      // jsr/jsr_w return to the next instruction.
      branchTargets.push(branch.getTarget(), stackDepth);
    } else {
      // check for instructions that terminate the method.
      if(opcode == Constants.ATHROW || opcode == Constants.RET ||
         (opcode >= Constants.IRETURN && opcode <= Constants.RETURN))
        ih = null;
    }
    // normal case, go to the next instruction.
    if(ih != null)
      ih = ih.getNext();
    // if we have no more instructions, see if there are any deferred branches to explore.
    if(ih == null) {
      BranchTarget bt = branchTargets.pop();
      if (bt != null) {
        ih = bt.target;
        stackDepth = bt.stackDepth;
      }
    }
  }

  return maxStackDepth;
}
Example 20
Source File: MethodGen.java    From jdk1.8-source-analysis with Apache License 2.0 4 votes vote down vote up 
/**
 * Computes stack usage of an instruction list by performing control flow analysis.
 *
 * @return maximum stack depth used by method
 */
public static int getMaxStack(ConstantPoolGen cp, InstructionList il, CodeExceptionGen[] et) {
  BranchStack branchTargets = new BranchStack();

  /* Initially, populate the branch stack with the exception
   * handlers, because these aren't (necessarily) branched to
   * explicitly. in each case, the stack will have depth 1,
   * containing the exception object.
   */
  for (int i = 0; i < et.length; i++) {
    InstructionHandle handler_pc = et[i].getHandlerPC();
    if (handler_pc != null)
      branchTargets.push(handler_pc, 1);
  }

  int               stackDepth = 0, maxStackDepth = 0;
  InstructionHandle ih         = il.getStart();

  while(ih != null) {
    Instruction instruction = ih.getInstruction();
    short opcode = instruction.getOpcode();
    int delta = instruction.produceStack(cp) - instruction.consumeStack(cp);

    stackDepth += delta;
    if(stackDepth > maxStackDepth)
      maxStackDepth = stackDepth;

    // choose the next instruction based on whether current is a branch.
    if(instruction instanceof BranchInstruction) {
      BranchInstruction branch = (BranchInstruction) instruction;
      if(instruction instanceof Select) {
        // explore all of the select's targets. the default target is handled below.
        Select select = (Select) branch;
        InstructionHandle[] targets = select.getTargets();
        for (int i = 0; i < targets.length; i++)
          branchTargets.push(targets[i], stackDepth);
        // nothing to fall through to.
        ih = null;
      } else if(!(branch instanceof IfInstruction)) {
        // if an instruction that comes back to following PC,
        // push next instruction, with stack depth reduced by 1.
        if(opcode == Constants.JSR || opcode == Constants.JSR_W)
          branchTargets.push(ih.getNext(), stackDepth - 1);
        ih = null;
      }
      // for all branches, the target of the branch is pushed on the branch stack.
      // conditional branches have a fall through case, selects don't, and
      // jsr/jsr_w return to the next instruction.
      branchTargets.push(branch.getTarget(), stackDepth);
    } else {
      // check for instructions that terminate the method.
      if(opcode == Constants.ATHROW || opcode == Constants.RET ||
         (opcode >= Constants.IRETURN && opcode <= Constants.RETURN))
        ih = null;
    }
    // normal case, go to the next instruction.
    if(ih != null)
      ih = ih.getNext();
    // if we have no more instructions, see if there are any deferred branches to explore.
    if(ih == null) {
      BranchTarget bt = branchTargets.pop();
      if (bt != null) {
        ih = bt.target;
        stackDepth = bt.stackDepth;
      }
    }
  }

  return maxStackDepth;
}