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package org.plumelib.bcelutil;
import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import org.apache.bcel.Const;
import org.apache.bcel.classfile.Attribute;
import org.apache.bcel.classfile.Constant;
import org.apache.bcel.classfile.ConstantUtf8;
import org.apache.bcel.classfile.StackMap;
import org.apache.bcel.classfile.StackMapEntry;
import org.apache.bcel.classfile.StackMapType;
import org.apache.bcel.generic.BasicType;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.IINC;
import org.apache.bcel.generic.IndexedInstruction;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.LocalVariableGen;
import org.apache.bcel.generic.LocalVariableInstruction;
import org.apache.bcel.generic.MethodGen;
import org.apache.bcel.generic.ObjectType;
import org.apache.bcel.generic.RET;
import org.apache.bcel.generic.Type;
import org.apache.bcel.verifier.VerificationResult;
import org.checkerframework.checker.index.qual.IndexOrLow;
import org.checkerframework.checker.index.qual.NonNegative;
import org.checkerframework.checker.interning.qual.InternedDistinct;
import org.checkerframework.checker.nullness.qual.EnsuresNonNull;
import org.checkerframework.checker.nullness.qual.Nullable;
import org.checkerframework.checker.signature.qual.ClassGetName;
import org.checkerframework.dataflow.qual.Pure;
/**
* This class provides methods to manipulate the StackMapTable. It is used to maintain and modify
* the StackMap for a method.
*
* BCEL should automatically build and maintain the StackMapTable in a manner similar to the
* LineNumberTable and the LocalVariableTable. However, for historical reasons, it does not.
*/
@SuppressWarnings("nullness")
public abstract class StackMapUtils {
/*
* NOMENCLATURE
*
* 'index' is an item's subscript into a data structure.
*
* 'offset' is an item's runtime address as an offset (for example)
* from the start of a method's byte codes or from the start
* of a method's stack frame. The Java Virtual Machine Specification
* uses 'index into the local variable array of the current frame'
* or 'slot number' to describe this later case.
*
* Unfortunately, BCEL uses the method names getIndex and setIndex
* to refer to 'offset's into the local stack frame.
* It uses getPosition and setPosition to refer to 'offset's into
* the byte codes.
*/
/** The pool for the method currently being processed. Must be set by the client. */
protected @Nullable ConstantPoolGen pool = null;
/** A log to which to print debugging information about program instrumentation. */
protected SimpleLog debug_instrument = new SimpleLog(false);
/** Whether or not the current method needs a StackMap. */
protected boolean needStackMap = false;
/** Working copy of StackMapTable; set by fetch_current_stack_map_table. */
protected StackMapEntry @Nullable [] stack_map_table = null;
/** Original stack map table attribute; set by fetch_current_stack_map_table. */
protected @Nullable StackMap smta = null;
/** Initial state of StackMapTypes for locals on method entry. */
protected StackMapType[] initial_type_list;
/** The number of local variables in this method prior to any modifications. */
protected int initial_locals_count;
/**
* The number of live local variables according to the current StackMap of interest. Set by
* update_stack_map_offset, find_stack_map_equal, find_stack_map_index_before, or
* find_stack_map_index_after.
*/
protected @NonNegative int number_active_locals;
/**
* Offset into code that corresponds to the current StackMap of interest. Set by
* find_stack_map_index_before.
*/
protected int running_offset;
/**
* The index of the first 'true' local in the local variable table. That is, after 'this' and any
* parameters.
*/
protected int first_local_index;
/** An empty StackMap used for initialization. */
@SuppressWarnings("interning") // @InternedDistinct initalization with fresh object
private StackMapEntry @InternedDistinct [] empty_stack_map_table = {};
/**
* A map from instructions that create uninitialized NEW objects to the corresponding StackMap
* entry. Set by build_unitialized_NEW_map.
*/
private Map uninitialized_NEW_map =
new HashMap();
/**
* Returns a String array with new_string added to the end of arr.
*
* @param arr original string array
* @param new_string string to be added
* @return the new string array
*/
protected String[] add_string(String[] arr, String new_string) {
String[] new_arr = new String[arr.length + 1];
for (int ii = 0; ii < arr.length; ii++) {
new_arr[ii] = arr[ii];
}
new_arr[arr.length] = new_string;
return new_arr;
}
/**
* Return the attribute name for the specified attribute.
*
* @param a the attribute
* @return the attribute name for the specified attribute
*/
@Pure
protected final String get_attribute_name(Attribute a) {
int con_index = a.getNameIndex();
Constant c = pool.getConstant(con_index);
String att_name = ((ConstantUtf8) c).getBytes();
return att_name;
}
/**
* Returns whether or not the specified attribute is a LocalVariableTypeTable.
*
* @param a the attribute
* @return true iff the attribute is a LocalVariableTypeTable
*/
@Pure
protected final boolean is_local_variable_type_table(Attribute a) {
return (get_attribute_name(a).equals("LocalVariableTypeTable"));
}
/**
* Returns whether or not the specified attribute is a StackMapTable.
*
* @param a the attribute
* @return true iff the attribute is a StackMapTable
*/
@Pure
protected final boolean is_stack_map_table(Attribute a) {
return (get_attribute_name(a).equals("StackMapTable"));
}
/**
* Find the StackMapTable attribute for a method. Return null if there isn't one.
*
* @param mgen the method
* @return the StackMapTable attribute for the method (or null if not present)
*/
@Pure
protected final @Nullable Attribute get_stack_map_table_attribute(MethodGen mgen) {
for (Attribute a : mgen.getCodeAttributes()) {
if (is_stack_map_table(a)) {
return a;
}
}
return null;
}
/**
* Find the LocalVariableTypeTable attribute for a method. Return null if there isn't one.
*
* @param mgen the method
* @return the LocalVariableTypeTable attribute for the method (or null if not present)
*/
@Pure
protected final @Nullable Attribute get_local_variable_type_table_attribute(MethodGen mgen) {
for (Attribute a : mgen.getCodeAttributes()) {
if (is_local_variable_type_table(a)) {
return a;
}
}
return null;
}
/**
* Remove the local variable type table attribute (LVTT) from mgen. Some instrumentation changes
* require this to be updated, but without BCEL support that would be hard to do. It should be
* safe to just delete it since it is optional and really only of use to a debugger.
*
* @param mgen the method to clear out
*/
protected final void remove_local_variable_type_table(MethodGen mgen) {
mgen.removeLocalVariableTypeTable();
}
/**
* We have inserted additional byte(s) into the instruction list; update the StackMaps, if
* required. Also sets running_offset.
*
* @param position the location of insertion
* @param delta the size of the insertion
*/
protected final void update_stack_map_offset(int position, int delta) {
running_offset = -1; // no +1 on first entry
for (int i = 0; i < stack_map_table.length; i++) {
running_offset = stack_map_table[i].getByteCodeOffset() + running_offset + 1;
if (running_offset > position) {
stack_map_table[i].updateByteCodeOffset(delta);
// Only update the first StackMap that occurs after the given
// offset as map offsets are relative to previous map entry.
return;
}
}
}
/**
* Find the StackMap entry whose offset matches the input argument. Also sets running_offset.
*
* @param offset byte code offset
* @return the corresponding StackMapEntry
*/
protected final StackMapEntry find_stack_map_equal(int offset) {
running_offset = -1; // no +1 on first entry
for (int i = 0; i < stack_map_table.length; i++) {
running_offset = stack_map_table[i].getByteCodeOffset() + running_offset + 1;
if (running_offset > offset) {
throw new RuntimeException("Invalid StackMap offset 1");
}
if (running_offset == offset) {
return stack_map_table[i];
}
// try next map entry
}
// no offset matched
throw new RuntimeException("Invalid StackMap offset 2");
}
/**
* Find the index of the StackMap entry whose offset is the last one before the input argument.
* Return -1 if there isn't one. Also sets running_offset and number_active_locals.
*
* @param offset byte code offset
* @return the corresponding StackMapEntry index
*/
protected final int find_stack_map_index_before(int offset) {
number_active_locals = initial_locals_count;
running_offset = -1; // no +1 on first entry
for (int i = 0; i < stack_map_table.length; i++) {
running_offset = running_offset + stack_map_table[i].getByteCodeOffset() + 1;
if (running_offset >= offset) {
if (i == 0) {
// reset offset to previous
running_offset = -1;
return -1;
} else {
// back up offset to previous
running_offset = running_offset - stack_map_table[i].getByteCodeOffset() - 1;
// return previous
return (i - 1);
}
}
// Update number of active locals based on this StackMap entry.
int frame_type = stack_map_table[i].getFrameType();
if (frame_type >= Const.APPEND_FRAME && frame_type <= Const.APPEND_FRAME_MAX) {
number_active_locals += frame_type - 251;
} else if (frame_type >= Const.CHOP_FRAME && frame_type <= Const.CHOP_FRAME_MAX) {
number_active_locals -= 251 - frame_type;
} else if (frame_type == Const.FULL_FRAME) {
number_active_locals = stack_map_table[i].getNumberOfLocals();
}
// All other frame_types do not modify locals.
}
if (stack_map_table.length == 0) {
return -1;
} else {
return stack_map_table.length - 1;
}
}
/**
* Find the index of the StackMap entry whose offset is the first one after the input argument.
* Return -1 if there isn't one. Also sets running_offset.
*
* @param offset byte code offset
* @return the corresponding StackMapEntry index
*/
protected final @IndexOrLow("stack_map_table") int find_stack_map_index_after(int offset) {
running_offset = -1; // no +1 on first entry
for (int i = 0; i < stack_map_table.length; i++) {
running_offset = running_offset + stack_map_table[i].getByteCodeOffset() + 1;
if (running_offset > offset) {
return i;
}
// try next map entry
}
// no such entry found
return -1;
}
/**
* Check to see if (due to some instruction modifications) there have been any changes in a switch
* statement's padding bytes. If so, then update the corresponding StackMap to reflect this
* change.
*
* @param ih where to start looking for a switch instruction
* @param il instruction list to search
*/
protected final void modify_stack_maps_for_switches(InstructionHandle ih, InstructionList il) {
Instruction inst;
short opcode;
if (!needStackMap) return;
// Make sure all instruction offsets are uptodate.
il.setPositions();
// Loop through each instruction looking for a switch
while (ih != null) {
inst = ih.getInstruction();
opcode = inst.getOpcode();
if (opcode == Const.TABLESWITCH || opcode == Const.LOOKUPSWITCH) {
int current_offset = ih.getPosition();
int index = find_stack_map_index_after(current_offset);
if (index == -1) {
throw new RuntimeException("Invalid StackMap offset 3");
}
StackMapEntry stack_map = stack_map_table[index];
int delta = (current_offset + inst.getLength()) - running_offset;
if (delta != 0) {
stack_map.updateByteCodeOffset(delta);
}
// Since StackMap offsets are relative to the previous one
// we only have to do the first one after a switch.
// But we do need to look at all the switch instructions.
}
// Go on to the next instruction in the list
ih = ih.getNext();
}
}
/**
* Find the live range of the compiler temp(s) at the given offset and create a LocalVariableGen
* for each. Note the compiler might generate temps of different sizes at the same offset (must
* have disjoint lifetimes).
*
* @param mgen the method
* @param offset compiler assigned local offset of hidden temp
* @return offset incremented by size of smallest temp found at offset
*/
protected final int gen_temp_locals(MethodGen mgen, int offset) {
int live_start = 0;
Type live_type = null;
InstructionList il = mgen.getInstructionList();
il.setPositions();
// Set up inital state of StackMap info on entry to method.
int locals_offset_height = 0;
int byte_code_offset = -1;
LocalVariableGen new_lvg;
int min_size = 3; // only sizes are 1 or 2; start with something larger.
number_active_locals = initial_locals_count;
StackMapType[] types_of_active_locals = new StackMapType[number_active_locals];
for (int ii = 0; ii < number_active_locals; ii++) {
types_of_active_locals[ii] = initial_type_list[ii];
locals_offset_height += getSize(initial_type_list[ii]);
}
// update state for each StackMap entry
for (StackMapEntry smte : stack_map_table) {
int frame_type = smte.getFrameType();
byte_code_offset += smte.getByteCodeOffset() + 1;
if (frame_type >= Const.APPEND_FRAME && frame_type <= Const.APPEND_FRAME_MAX) {
// number to append is frame_type - 251
types_of_active_locals =
Arrays.copyOf(types_of_active_locals, number_active_locals + frame_type - 251);
for (StackMapType smt : smte.getTypesOfLocals()) {
types_of_active_locals[number_active_locals++] = smt;
locals_offset_height += getSize(smt);
}
} else if (frame_type >= Const.CHOP_FRAME && frame_type <= Const.CHOP_FRAME_MAX) {
int number_to_chop = 251 - frame_type;
while (number_to_chop > 0) {
locals_offset_height -= getSize(types_of_active_locals[--number_active_locals]);
number_to_chop--;
}
types_of_active_locals = Arrays.copyOf(types_of_active_locals, number_active_locals);
} else if (frame_type == Const.FULL_FRAME) {
locals_offset_height = 0;
number_active_locals = 0;
types_of_active_locals = new StackMapType[smte.getNumberOfLocals()];
for (StackMapType smt : smte.getTypesOfLocals()) {
types_of_active_locals[number_active_locals++] = smt;
locals_offset_height += getSize(smt);
}
}
// all other frame_types do not modify locals.
// System.out.printf("byte_code_offset: %d, temp offset: %d, locals_offset_height: %d,
// number_active_locals: %d, local types: %s%n",
// byte_code_offset, offset, locals_offset_height, number_active_locals,
// Arrays.toString(types_of_active_locals));
if (live_start == 0) {
// did the latest StackMap entry define the temp in question?
if (offset < locals_offset_height) {
live_start = byte_code_offset;
int running_offset = 0;
for (StackMapType smt : types_of_active_locals) {
if (running_offset == offset) {
live_type = generate_Type_from_StackMapType(smt);
break;
}
running_offset += getSize(smt);
}
if (live_type == null) {
// No matching offset in stack maps so this offset must be
// second half of long or double. Just skip to next stack map.
live_start = 0;
}
}
} else {
// did the latest StackMap entry undefine the temp in question?
if (offset >= locals_offset_height) {
// create the temp variable
new_lvg =
mgen.addLocalVariable(
"DaIkOnTeMp" + offset,
live_type,
offset,
il.findHandle(live_start),
il.findHandle(byte_code_offset));
debug_instrument.log(
"Added local %s, %d, %d : %s, %s%n",
new_lvg.getIndex(),
new_lvg.getStart().getPosition(),
new_lvg.getEnd().getPosition(),
new_lvg.getName(),
new_lvg.getType());
min_size = Math.min(min_size, live_type.getSize());
// reset to look for more temps at same offset
live_start = 0;
live_type = null;
}
}
// go on to next StackMap entry
}
// we are done with stack maps; need to see if any temps still active
if (live_start != 0) {
// live range is to end of method; create the temp variable
new_lvg =
mgen.addLocalVariable(
"DaIkOnTeMp" + offset, live_type, offset, il.findHandle(live_start), null);
debug_instrument.log(
"Added local %s, %d, %d : %s, %s%n",
new_lvg.getIndex(),
new_lvg.getStart().getPosition(),
il.getEnd().getPosition(),
new_lvg.getName(),
new_lvg.getType());
min_size = Math.min(min_size, live_type.getSize());
} else {
if (min_size == 3) {
// did not find a temp in any of the stack maps; that must mean the
// temp live range is in between two stack maps or after last stack map
// need to scan all byte codes to get live range and type
// HACK: for now, just make a guess and put it after last stack map
// Note we may be defining a bogus temp for second half of long or double.
if (byte_code_offset == -1) {
// no stack maps at all, set start to 0
byte_code_offset = 0;
}
new_lvg =
mgen.addLocalVariable(
"DaIkOnTeMp" + offset, Type.OBJECT, offset, il.findHandle(byte_code_offset), null);
debug_instrument.log(
"Added local %s, %d, %d : %s, %s%n",
new_lvg.getIndex(),
new_lvg.getStart().getPosition(),
il.getEnd().getPosition(),
new_lvg.getName(),
new_lvg.getType());
min_size = Math.min(min_size, Type.OBJECT.getSize());
}
}
return offset + min_size;
}
/**
* We need to locate and remember any NEW instructions that create uninitialized objects. Their
* offset may be contained in a StackMap entry and will probably need to be updated as we add
* instrumentation code. Note that these instructions are fairly rare.
*
* @param il instruction list to search
*/
protected final void build_unitialized_NEW_map(InstructionList il) {
uninitialized_NEW_map.clear();
il.setPositions();
for (StackMapEntry smte : stack_map_table) {
int frame_type = smte.getFrameType();
if ((frame_type >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME
&& frame_type <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED)
|| (frame_type >= Const.APPEND_FRAME && frame_type <= Const.APPEND_FRAME_MAX)
|| (frame_type == Const.FULL_FRAME)) {
if (smte.getNumberOfLocals() > 0) {
for (StackMapType smt : smte.getTypesOfLocals()) {
if (smt.getType() == Const.ITEM_NewObject) {
int i = smt.getIndex();
uninitialized_NEW_map.put(il.findHandle(i), i);
}
}
}
if (smte.getNumberOfStackItems() > 0) {
for (StackMapType smt : smte.getTypesOfStackItems()) {
if (smt.getType() == Const.ITEM_NewObject) {
int i = smt.getIndex();
uninitialized_NEW_map.put(il.findHandle(i), i);
}
}
}
}
}
}
/**
* One of uninitialized NEW instructions has moved. Update its offset in StackMap entries. Note
* that more than one entry could refer to the same instruction. This is a helper routine used by
* update_uninitialized_NEW_offsets.
*
* @param old_offset original location of NEW instruction
* @param new_offset new location of NEW instruction
*/
private final void update_NEW_object_stack_map_entries(int old_offset, int new_offset) {
for (StackMapEntry smte : stack_map_table) {
int frame_type = smte.getFrameType();
if ((frame_type >= Const.SAME_LOCALS_1_STACK_ITEM_FRAME
&& frame_type <= Const.SAME_LOCALS_1_STACK_ITEM_FRAME_EXTENDED)
|| (frame_type >= Const.APPEND_FRAME && frame_type <= Const.APPEND_FRAME_MAX)
|| (frame_type == Const.FULL_FRAME)) {
if (smte.getNumberOfLocals() > 0) {
for (StackMapType smt : smte.getTypesOfLocals()) {
if (smt.getType() == Const.ITEM_NewObject) {
if (old_offset == smt.getIndex()) {
smt.setIndex(new_offset);
}
}
}
}
if (smte.getNumberOfStackItems() > 0) {
for (StackMapType smt : smte.getTypesOfStackItems()) {
if (smt.getType() == Const.ITEM_NewObject) {
if (old_offset == smt.getIndex()) {
smt.setIndex(new_offset);
}
}
}
}
}
}
}
/**
* Check to see if any of the uninitialized NEW instructions have moved. Again, these are rare, so
* a linear pass is fine.
*
* @param il instruction list to search
*/
protected final void update_uninitialized_NEW_offsets(InstructionList il) {
il.setPositions();
for (Map.Entry e : uninitialized_NEW_map.entrySet()) {
InstructionHandle ih = e.getKey();
int old_offset = e.getValue().intValue();
int new_offset = ih.getPosition();
if (old_offset != new_offset) {
update_NEW_object_stack_map_entries(old_offset, new_offset);
e.setValue(new_offset);
}
}
}
/**
* Process the instruction list, adding size (1 or 2) to the index of each Instruction that
* references a local that is equal or higher in the local map than index_first_moved_local. Size
* should be the size of the new local that was just inserted at index_first_moved_local.
*
* @param mgen MethodGen to be modified
* @param index_first_moved_local original index of first local moved "up"
* @param size size of new local added (1 or 2)
*/
protected final void adjust_code_for_locals_change(
MethodGen mgen, int index_first_moved_local, int size) {
InstructionList il = mgen.getInstructionList();
for (InstructionHandle ih = il.getStart(); ih != null; ih = ih.getNext()) {
Instruction inst = ih.getInstruction();
int orig_length = inst.getLength();
int operand;
if ((inst instanceof RET) || (inst instanceof IINC)) {
IndexedInstruction index_inst = (IndexedInstruction) inst;
if (index_inst.getIndex() >= index_first_moved_local) {
index_inst.setIndex(index_inst.getIndex() + size);
}
} else if (inst instanceof LocalVariableInstruction) {
// BCEL handles all the details of which opcode and if index
// is implicit or explicit; also, and if needs to be WIDE.
operand = ((LocalVariableInstruction) inst).getIndex();
if (operand >= index_first_moved_local) {
((LocalVariableInstruction) inst).setIndex(operand + size);
}
}
// Unfortunately, BCEL doesn't take care of incrementing the
// offset within StackMapEntrys.
int delta = inst.getLength() - orig_length;
if (delta > 0) {
il.setPositions();
update_stack_map_offset(ih.getPosition(), delta);
modify_stack_maps_for_switches(ih, il);
}
}
}
/**
* Get existing StackMapTable from the MethodGen arguments. If there is none, create a new empty
* one. Sets both smta and stack_map_table. Must be called prior to any other methods that
* manipulate the stack_map_table!
*
* @param mgen MethodGen to search
* @param java_class_version Java version for the classfile; stack_map_table is optional before
* Java 1.7 (= classfile version 51)
*/
@EnsuresNonNull({"stack_map_table"})
protected final void fetch_current_stack_map_table(MethodGen mgen, int java_class_version) {
smta = (StackMap) get_stack_map_table_attribute(mgen);
if (smta != null) {
// get a deep copy of the original StackMapTable.
stack_map_table = ((StackMap) (smta.copy(smta.getConstantPool()))).getStackMap();
needStackMap = true;
debug_instrument.log(
"Attribute tag: %s length: %d nameIndex: %d%n",
smta.getTag(), smta.getLength(), smta.getNameIndex());
// Delete existing stack map - we'll add a new one later.
mgen.removeCodeAttribute(smta);
} else {
stack_map_table = empty_stack_map_table;
if (java_class_version > Const.MAJOR_1_6) {
needStackMap = true;
}
}
print_stack_map_table("Original");
}
/**
* Print the contents of the StackMapTable to the debug_instrument.log.
*
* @param prefix label to display with table
*/
protected final void print_stack_map_table(String prefix) {
debug_instrument.log("%nStackMap(%s) %s items:%n", prefix, stack_map_table.length);
running_offset = -1; // no +1 on first entry
for (int i = 0; i < stack_map_table.length; i++) {
running_offset = stack_map_table[i].getByteCodeOffset() + running_offset + 1;
debug_instrument.log("@%03d %s %n", running_offset, stack_map_table[i]);
}
}
/**
* Create a new StackMap code attribute from stack_map_table.
*
* @param mgen MethodGen to add attribute to
* @throws IOException if cannot create the attribute
*/
protected final void create_new_stack_map_attribute(MethodGen mgen) throws IOException {
if (!needStackMap) return;
if (stack_map_table == empty_stack_map_table) return;
print_stack_map_table("Final");
// Build new StackMapTable attribute
StackMap map_table =
new StackMap(pool.addUtf8("StackMapTable"), 0, null, pool.getConstantPool());
map_table.setStackMap(stack_map_table);
mgen.addCodeAttribute(map_table);
}
/**
* Convert a Type name to a Class name.
*
* @param t type whose name is to be converted
* @return a String containing the class name
*/
@SuppressWarnings("signature") // conversion routine
protected static @ClassGetName String typeToClassGetName(Type t) {
if (t instanceof ObjectType) {
return ((ObjectType) t).getClassName();
} else if (t instanceof BasicType) {
// Use reserved keyword for basic type rather than signature to
// avoid conflicts with user defined types.
return t.toString();
} else {
// Array type: just convert '/' to '.'
return t.getSignature().replace('/', '.');
}
}
/**
* Convert a Type to a StackMapType.
*
* @param t Type to be converted
* @return result StackMapType
*/
protected final StackMapType generate_StackMapType_from_Type(Type t) {
switch (t.getType()) {
case Const.T_BOOLEAN:
case Const.T_CHAR:
case Const.T_BYTE:
case Const.T_SHORT:
case Const.T_INT:
return new StackMapType(Const.ITEM_Integer, -1, pool.getConstantPool());
case Const.T_FLOAT:
return new StackMapType(Const.ITEM_Float, -1, pool.getConstantPool());
case Const.T_DOUBLE:
return new StackMapType(Const.ITEM_Double, -1, pool.getConstantPool());
case Const.T_LONG:
return new StackMapType(Const.ITEM_Long, -1, pool.getConstantPool());
case Const.T_ARRAY:
case Const.T_OBJECT:
return new StackMapType(
Const.ITEM_Object, pool.addClass(typeToClassGetName(t)), pool.getConstantPool());
// UNKNOWN seems to be used for Uninitialized objects.
// The second argument to the constructor should be the code offset
// of the corresponding 'new' instruction. Just using 0 for now.
case Const.T_UNKNOWN:
return new StackMapType(Const.ITEM_NewObject, 0, pool.getConstantPool());
default:
throw new RuntimeException("Invalid type: " + t + t.getType());
}
}
/**
* Convert a StackMapType to a Type.
*
* @param smt StackMapType to be converted
* @return result Type
*/
protected final Type generate_Type_from_StackMapType(StackMapType smt) {
switch (smt.getType()) {
case Const.ITEM_Integer:
case Const.ITEM_Bogus: // not sure about this; reresents 'top'?
return Type.INT;
case Const.ITEM_Float:
return Type.FLOAT;
case Const.ITEM_Double:
return Type.DOUBLE;
case Const.ITEM_Long:
return Type.LONG;
case Const.ITEM_Object:
return Type.OBJECT;
default:
Thread.dumpStack();
assert false : "Invalid StackMapType: " + smt + smt.getType();
throw new RuntimeException("Invalid StackMapType: " + smt + smt.getType());
}
}
/**
* @param smt a StackMapType object
* @return operand size of this type (2 for long and double, 1 otherwise)
*/
protected final int getSize(StackMapType smt) {
switch (smt.getType()) {
case Const.ITEM_Double:
case Const.ITEM_Long:
return 2;
default:
return 1;
}
}
/**
* Update any FULL_FRAME StackMap entries to include a new local var. The locals array is a copy
* of the local variables PRIOR to the addition of the new local in question.
*
* @param offset offset into stack of the new variable we are adding
* @param type_new_var type of new variable we are adding
* @param locals a copy of the local variable table prior to this modification
*/
protected final void update_full_frame_stack_map_entries(
int offset, Type type_new_var, LocalVariableGen[] locals) {
@NonNegative int index; // locals index
for (int i = 0; i < stack_map_table.length; i++) {
if (stack_map_table[i].getFrameType() == Const.FULL_FRAME) {
int num_locals = stack_map_table[i].getNumberOfLocals();
StackMapType[] new_local_types = new StackMapType[num_locals + 1];
StackMapType[] old_local_types = stack_map_table[i].getTypesOfLocals();
// System.out.printf ("update_full_frame %s %s %s %n", offset, num_locals, locals.length);
for (index = 0; index < num_locals; index++) {
if (index >= locals.length) {
// there are hidden compiler temps in map
break;
}
if (locals[index].getIndex() >= offset) {
// we've reached the point of insertion
break;
}
new_local_types[index] = old_local_types[index];
}
new_local_types[index++] = generate_StackMapType_from_Type(type_new_var);
while (index <= num_locals) {
new_local_types[index] = old_local_types[index - 1];
index++;
}
stack_map_table[i].setTypesOfLocals(new_local_types);
}
}
}
/**
* Add a new argument to the method. This will be added after last current argument and before the
* first local variable. This might have the side effect of causing us to rewrite the method byte
* codes to adjust the offsets for the local variables - see below for details.
*
* Must call fix_local_variable_table (just once per method) before calling this routine.
*
* @param mgen MethodGen to be modified
* @param arg_name name of new argument
* @param arg_type type of new argument
* @return a LocalVariableGen for the new argument
*/
protected final LocalVariableGen add_new_argument(
MethodGen mgen, String arg_name, Type arg_type) {
// We add a new argument, after any current ones, and then
// we need to make a pass over the byte codes to update the local
// offset values of all the locals we just shifted up. This may have
// a 'knock on' effect if we are forced to change an instruction that
// references implict local #3 to an instruction with an explict
// reference to local #4 as this would require the insertion of an
// offset into the byte codes. This means we would need to make an
// additional pass to update branch targets (no - BCEL does this for
// us) and the StackMapTable (yes - BCEL should do this, but it doesn't).
//
LocalVariableGen arg_new = null;
// get a copy of the locals before modification
LocalVariableGen[] locals = mgen.getLocalVariables();
Type[] arg_types = mgen.getArgumentTypes();
int new_index = 0;
int new_offset = 0;
boolean has_code = (mgen.getInstructionList() != null);
if (has_code) {
if (!mgen.isStatic()) {
// Skip the 'this' pointer argument.
new_index++;
new_offset++; // size of 'this' is 1
}
if (arg_types.length > 0) {
LocalVariableGen last_arg;
new_index = new_index + arg_types.length;
// new_index is now positive, because arg_types.length is
last_arg = locals[new_index - 1];
new_offset = last_arg.getIndex() + (last_arg.getType()).getSize();
}
// Insert our new local variable into existing table at 'new_offset'.
arg_new = mgen.addLocalVariable(arg_name, arg_type, new_offset, null, null);
// Update the index of the first 'true' local in the local variable table.
first_local_index++;
}
initial_locals_count++;
// Update the method's argument information.
arg_types = BcelUtil.postpendToArray(arg_types, arg_type);
String[] arg_names = add_string(mgen.getArgumentNames(), arg_name);
mgen.setArgumentTypes(arg_types);
mgen.setArgumentNames(arg_names);
if (has_code) {
// we need to adjust the offset of any locals after our insertion
for (int i = new_index; i < locals.length; i++) {
LocalVariableGen lv = locals[i];
lv.setIndex(lv.getIndex() + arg_type.getSize());
}
mgen.setMaxLocals(mgen.getMaxLocals() + arg_type.getSize());
debug_instrument.log(
"Added arg %s%n",
arg_new.getIndex() + ": " + arg_new.getName() + ", " + arg_new.getType());
// Now process the instruction list, adding one to the offset
// within each LocalVariableInstruction that references a
// local that is 'higher' in the local map than new local
// we just inserted.
adjust_code_for_locals_change(mgen, new_offset, arg_type.getSize());
// Finally, we need to update any FULL_FRAME StackMap entries to
// add in the new local variable type.
update_full_frame_stack_map_entries(new_offset, arg_type, locals);
debug_instrument.log("New LocalVariableTable:%n%s%n", mgen.getLocalVariableTable(pool));
}
return arg_new;
}
/**
* Create a new local with a scope of the full method. This means we need to search the existing
* locals to find the proper index for our new local. This might have the side effect of causing
* us to rewrite the method byte codes to adjust the offsets for the existing local variables -
* see below for details.
*
*
Must call fix_local_variable_table (just once per method) before calling this routine.
*
* @param mgen MethodGen to be modified
* @param local_name name of new local
* @param local_type type of new local
* @return a LocalVariableGen for the new local
*/
protected final LocalVariableGen create_method_scope_local(
MethodGen mgen, String local_name, Type local_type) {
// BCEL sorts local vars and presents them in offset order. Search
// locals for first var with start != 0. If none, just add the new
// var at the end of the table and exit. Otherwise, insert the new
// var just prior to the local we just found.
// Now we need to make a pass over the byte codes to update the local
// offset values of all the locals we just shifted up. This may have
// a 'knock on' effect if we are forced to change an instruction that
// references implict local #3 to an instruction with an explict
// reference to local #4 as this would require the insertion of an
// offset into the byte codes. This means we would need to make an
// additional pass to update branch targets (no - BCEL does this for
// us) and the StackMapTable (yes - BCEL should do this, but it doesn't).
//
// We never want to insert our local prior to any parameters. This would
// happen naturally, but some old class files have non zero addresses
// for 'this' and/or the parameters so we need to add an explicit
// check to make sure we skip these variables.
LocalVariableGen lv_new;
int max_offset = 0;
int new_offset = -1;
// get a copy of the local before modification
LocalVariableGen[] locals = mgen.getLocalVariables();
@IndexOrLow("locals") int compiler_temp_i = -1;
int new_index = -1;
int i;
for (i = 0; i < locals.length; i++) {
LocalVariableGen lv = locals[i];
if (i >= first_local_index) {
if (lv.getStart().getPosition() != 0) {
if (new_offset == -1) {
if (compiler_temp_i != -1) {
new_offset = locals[compiler_temp_i].getIndex();
new_index = compiler_temp_i;
} else {
new_offset = lv.getIndex();
new_index = i;
}
}
}
}
// calculate max local size seen so far (+1)
max_offset = lv.getIndex() + lv.getType().getSize();
if (lv.getName().startsWith("DaIkOnTeMp")) {
// Remember the index of a compiler temp. We may wish
// to insert our new local prior to a temp to simplfy
// the generation of StackMaps.
if (compiler_temp_i == -1) {
compiler_temp_i = i;
}
} else {
// If there were compiler temps prior to this local, we don't
// need to worry about them as the compiler will have already
// included them in the StackMaps. Reset the indicators.
compiler_temp_i = -1;
}
}
// We have looked at all the local variables; if we have not found
// a place for our new local, check to see if last local was a
// compiler temp and insert prior.
if ((new_offset == -1) && (compiler_temp_i != -1)) {
new_offset = locals[compiler_temp_i].getIndex();
new_index = compiler_temp_i;
}
// If new_offset is still unset, we can just add our local at the
// end. There may be unnamed compiler temps here, so we need to
// check for this (via max_offset) and move them up.
if (new_offset == -1) {
new_offset = max_offset;
if (new_offset < mgen.getMaxLocals()) {
mgen.setMaxLocals(mgen.getMaxLocals() + local_type.getSize());
}
lv_new = mgen.addLocalVariable(local_name, local_type, new_offset, null, null);
} else {
// insert our new local variable into existing table at 'new_offset'
lv_new = mgen.addLocalVariable(local_name, local_type, new_offset, null, null);
// we need to adjust the offset of any locals after our insertion
for (i = new_index; i < locals.length; i++) {
LocalVariableGen lv = locals[i];
lv.setIndex(lv.getIndex() + local_type.getSize());
}
mgen.setMaxLocals(mgen.getMaxLocals() + local_type.getSize());
}
debug_instrument.log(
"Added local %s%n", lv_new.getIndex() + ": " + lv_new.getName() + ", " + lv_new.getType());
// Now process the instruction list, adding one to the offset
// within each LocalVariableInstruction that references a
// local that is 'higher' in the local map than new local
// we just inserted.
adjust_code_for_locals_change(mgen, new_offset, local_type.getSize());
// Finally, we need to update any FULL_FRAME StackMap entries to
// add in the new local variable type.
update_full_frame_stack_map_entries(new_offset, local_type, locals);
debug_instrument.log("New LocalVariableTable:%n%s%n", mgen.getLocalVariableTable(pool));
return lv_new;
}
/**
* Under some circumstances, there may be problems with the local variable table. These problems
* occur when the Java compiler adds unnamed entries. There may be unnamed parameters and/or
* unnamed local variables. These items appear as gaps in the LocalVariable table. This routine
* creates LocalVariable entries for these missing items.
*
*
* - The java Compiler allocates a hidden parameter for the constructor of an inner class.
* These items are given the name $hidden$ appended with their offset.
*
- The Java compiler allocates unnamed local temps for:
*
* - saving the exception in a finally clause
*
- the lock for a synchronized block
*
- interators
*
- (others?)
*
* These items are given the name DaIkOnTeMp appended with their offset.
*
*
* @param mgen MethodGen to be modified
*/
protected final void fix_local_variable_table(MethodGen mgen) {
InstructionList il = mgen.getInstructionList();
if (il == null) {
// no code so nothing to do
first_local_index = 0;
return;
}
// Get the current local variables (includes 'this' and parameters)
LocalVariableGen[] locals = mgen.getLocalVariables();
LocalVariableGen l;
LocalVariableGen new_lvg;
// We need a deep copy
for (int ii = 0; ii < locals.length; ii++) {
locals[ii] = (LocalVariableGen) (locals[ii].clone());
}
// The arg types are correct and include all parameters.
Type[] arg_types = mgen.getArgumentTypes();
// Initial offset into the stack frame
int offset = 0;
// Index into locals of the first parameter
int loc_index = 0;
// Rarely, the java compiler gets the max locals count wrong (too big).
// This would cause problems for us later, so we need to recalculate
// the highest local used based on looking at code offsets.
mgen.setMaxLocals();
int max_locals = mgen.getMaxLocals();
// Remove the existing locals
mgen.removeLocalVariables();
// Reset MaxLocals to 0 and let code below rebuild it.
mgen.setMaxLocals(0);
// Determine the first 'true' local index into the local variables.
// The object 'this' pointer and the parameters form the first n
// entries in the list.
first_local_index = arg_types.length;
if (!mgen.isStatic()) {
// Add the 'this' pointer argument back in.
l = locals[0];
new_lvg = mgen.addLocalVariable(l.getName(), l.getType(), l.getIndex(), null, null);
debug_instrument.log(
"Added %s%n",
new_lvg.getIndex() + ": " + new_lvg.getName() + ", " + new_lvg.getType());
loc_index = 1;
offset = 1;
first_local_index++;
}
// Loop through each argument
for (int ii = 0; ii < arg_types.length; ii++) {
// If this parameter doesn't have a matching local
if ((loc_index >= locals.length) || (offset != locals[loc_index].getIndex())) {
// Create a local variable to describe the missing argument
new_lvg = mgen.addLocalVariable("$hidden$" + offset, arg_types[ii], offset, null, null);
} else {
l = locals[loc_index];
new_lvg = mgen.addLocalVariable(l.getName(), l.getType(), l.getIndex(), null, null);
loc_index++;
}
debug_instrument.log(
"Added param %s%n",
new_lvg.getIndex() + ": " + new_lvg.getName() + ", " + new_lvg.getType());
offset += arg_types[ii].getSize();
}
// At this point the LocalVaraibles contain:
// the 'this' pointer (if present)
// the arguments to the method
// This will be used to construct the initial state of the
// StackMapTypes.
LocalVariableGen[] initial_locals = mgen.getLocalVariables();
initial_locals_count = initial_locals.length;
initial_type_list = new StackMapType[initial_locals_count];
for (int ii = 0; ii < initial_locals_count; ii++) {
initial_type_list[ii] = generate_StackMapType_from_Type(initial_locals[ii].getType());
}
// Add back the true locals
//
// NOTE that the Java compiler uses unnamed local temps for:
// saving the exception in a finally clause
// the lock for a synchronized block
// iterators
// (others?)
// We will create a 'fake' local for these cases.
for (int ii = first_local_index; ii < locals.length; ii++) {
l = locals[ii];
if (l.getIndex() > offset) {
// A gap in index values indicates a compiler allocated temp.
// (if offset is 0, probably a lock object)
// there is at least one hidden compiler temp before the next local
offset = gen_temp_locals(mgen, offset);
ii--; // need to revisit same local
} else {
new_lvg =
mgen.addLocalVariable(l.getName(), l.getType(), l.getIndex(), l.getStart(), l.getEnd());
debug_instrument.log(
"Added local %s%n",
new_lvg.getIndex() + ": " + new_lvg.getName() + ", " + new_lvg.getType());
offset = new_lvg.getIndex() + (new_lvg.getType()).getSize();
}
}
// check for hidden temps after last declared local.
while (offset < max_locals) {
offset = gen_temp_locals(mgen, offset);
}
// Recalculate the highest local used based on looking at code offsets.
mgen.setMaxLocals();
}
/**
* Calculates the types on the stack for each instruction using the BCEL stack verification
* routines.
*
* @param mg MethodGen for the method to be analyzed
* @return a StackTypes object for the method
*/
protected final StackTypes bcel_calc_stack_types(MethodGen mg) {
StackVer stackver = new StackVer();
VerificationResult vr;
try {
vr = stackver.do_stack_ver(mg);
} catch (Throwable t) {
System.out.printf("Warning: StackVer exception for %s.%s%n", mg.getClassName(), mg.getName());
System.out.printf("Exception: %s%n", t);
System.out.printf("Method is NOT instrumented%n");
return null;
}
if (vr != VerificationResult.VR_OK) {
System.out.printf(
"Warning: StackVer failed for %s.%s: %s%n", mg.getClassName(), mg.getName(), vr);
System.out.printf("Method is NOT instrumented%n");
return null;
}
assert vr == VerificationResult.VR_OK : " vr failed " + vr;
return stackver.get_stack_types();
}
}