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com.android.dx.dex.file.DebugInfoEncoder Maven / Gradle / Ivy

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * 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.android.dx.dex.file;

import com.android.dex.util.ExceptionWithContext;
import com.android.dx.dex.code.LocalList;
import com.android.dx.dex.code.PositionList;
import static com.android.dx.dex.file.DebugInfoConstants.DBG_ADVANCE_LINE;
import static com.android.dx.dex.file.DebugInfoConstants.DBG_ADVANCE_PC;
import static com.android.dx.dex.file.DebugInfoConstants.DBG_END_LOCAL;
import static com.android.dx.dex.file.DebugInfoConstants.DBG_END_SEQUENCE;
import static com.android.dx.dex.file.DebugInfoConstants.DBG_FIRST_SPECIAL;
import static com.android.dx.dex.file.DebugInfoConstants.DBG_LINE_BASE;
import static com.android.dx.dex.file.DebugInfoConstants.DBG_LINE_RANGE;
import static com.android.dx.dex.file.DebugInfoConstants.DBG_RESTART_LOCAL;
import static com.android.dx.dex.file.DebugInfoConstants.DBG_SET_PROLOGUE_END;
import static com.android.dx.dex.file.DebugInfoConstants.DBG_START_LOCAL;
import static com.android.dx.dex.file.DebugInfoConstants.DBG_START_LOCAL_EXTENDED;
import com.android.dx.rop.code.RegisterSpec;
import com.android.dx.rop.code.SourcePosition;
import com.android.dx.rop.cst.CstMethodRef;
import com.android.dx.rop.cst.CstString;
import com.android.dx.rop.cst.CstType;
import com.android.dx.rop.type.Prototype;
import com.android.dx.rop.type.StdTypeList;
import com.android.dx.rop.type.Type;
import com.android.dx.util.AnnotatedOutput;
import com.android.dx.util.ByteArrayAnnotatedOutput;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.BitSet;
import java.util.Collections;
import java.util.Comparator;

/**
 * An encoder for the dex debug info state machine format. The format
 * for each method enrty is as follows:
 * 
    *
  1. signed LEB128: initial value for line register. *
  2. n instances of signed LEB128: string indicies (offset by 1) * for each method argument in left-to-right order * with {@code this} excluded. A value of '0' indicates "no name" *
  3. A sequence of special or normal opcodes as defined in * {@code DebugInfoConstants}. *
  4. A single terminating {@code OP_END_SEQUENCE} *
*/ public final class DebugInfoEncoder { private static final boolean DEBUG = false; /** {@code null-ok;} positions (line numbers) to encode */ private final PositionList positions; /** {@code null-ok;} local variables to encode */ private final LocalList locals; private final ByteArrayAnnotatedOutput output; private final DexFile file; private final int codeSize; private final int regSize; private final Prototype desc; private final boolean isStatic; /** current encoding state: bytecode address */ private int address = 0; /** current encoding state: line number */ private int line = 1; /** * if non-null: the output to write annotations to. No normal * output is written to this. */ private AnnotatedOutput annotateTo; /** if non-null: another possible output for annotations */ private PrintWriter debugPrint; /** if non-null: the prefix for each annotation or debugPrint line */ private String prefix; /** true if output should be consumed during annotation */ private boolean shouldConsume; /** indexed by register; last local alive in register */ private final LocalList.Entry[] lastEntryForReg; /** * Creates an instance. * * @param positions {@code null-ok;} positions (line numbers) to encode * @param locals {@code null-ok;} local variables to encode * @param file {@code null-ok;} may only be {@code null} if simply using * this class to do a debug print * @param codeSize * @param regSize * @param isStatic * @param ref */ public DebugInfoEncoder(PositionList positions, LocalList locals, DexFile file, int codeSize, int regSize, boolean isStatic, CstMethodRef ref) { this.positions = positions; this.locals = locals; this.file = file; this.desc = ref.getPrototype(); this.isStatic = isStatic; this.codeSize = codeSize; this.regSize = regSize; output = new ByteArrayAnnotatedOutput(); lastEntryForReg = new LocalList.Entry[regSize]; } /** * Annotates or writes a message to the {@code debugPrint} writer * if applicable. * * @param length the number of bytes associated with this message * @param message the message itself */ private void annotate(int length, String message) { if (prefix != null) { message = prefix + message; } if (annotateTo != null) { annotateTo.annotate(shouldConsume ? length : 0, message); } if (debugPrint != null) { debugPrint.println(message); } } /** * Converts this (PositionList, LocalList) pair into a state machine * sequence. * * @return {@code non-null;} encoded byte sequence without padding and * terminated with a {@code 0x00} byte */ public byte[] convert() { try { byte[] ret; ret = convert0(); if (DEBUG) { for (int i = 0 ; i < ret.length; i++) { System.err.printf("byte %02x\n", (0xff & ret[i])); } } return ret; } catch (IOException ex) { throw ExceptionWithContext .withContext(ex, "...while encoding debug info"); } } /** * Converts and produces annotations on a stream. Does not write * actual bits to the {@code AnnotatedOutput}. * * @param prefix {@code null-ok;} prefix to attach to each line of output * @param debugPrint {@code null-ok;} if specified, an alternate output for * annotations * @param out {@code null-ok;} if specified, where annotations should go * @param consume whether to claim to have consumed output for * {@code out} * @return {@code non-null;} encoded output */ public byte[] convertAndAnnotate(String prefix, PrintWriter debugPrint, AnnotatedOutput out, boolean consume) { this.prefix = prefix; this.debugPrint = debugPrint; annotateTo = out; shouldConsume = consume; byte[] result = convert(); return result; } private byte[] convert0() throws IOException { ArrayList sortedPositions = buildSortedPositions(); ArrayList methodArgs = extractMethodArguments(); emitHeader(sortedPositions, methodArgs); // TODO: Make this mark be the actual prologue end. output.writeByte(DBG_SET_PROLOGUE_END); if (annotateTo != null || debugPrint != null) { annotate(1, String.format("%04x: prologue end",address)); } int positionsSz = sortedPositions.size(); int localsSz = locals.size(); // Current index in sortedPositions int curPositionIdx = 0; // Current index in locals int curLocalIdx = 0; for (;;) { /* * Emit any information for the current address. */ curLocalIdx = emitLocalsAtAddress(curLocalIdx); curPositionIdx = emitPositionsAtAddress(curPositionIdx, sortedPositions); /* * Figure out what the next important address is. */ int nextAddrL = Integer.MAX_VALUE; // local variable int nextAddrP = Integer.MAX_VALUE; // position (line number) if (curLocalIdx < localsSz) { nextAddrL = locals.get(curLocalIdx).getAddress(); } if (curPositionIdx < positionsSz) { nextAddrP = sortedPositions.get(curPositionIdx).getAddress(); } int next = Math.min(nextAddrP, nextAddrL); // No next important address == done. if (next == Integer.MAX_VALUE) { break; } /* * If the only work remaining are local ends at the end of the * block, stop here. Those are implied anyway. */ if (next == codeSize && nextAddrL == Integer.MAX_VALUE && nextAddrP == Integer.MAX_VALUE) { break; } if (next == nextAddrP) { // Combined advance PC + position entry emitPosition(sortedPositions.get(curPositionIdx++)); } else { emitAdvancePc(next - address); } } emitEndSequence(); return output.toByteArray(); } /** * Emits all local variable activity that occurs at the current * {@link #address} starting at the given index into {@code * locals} and including all subsequent activity at the same * address. * * @param curLocalIdx Current index in locals * @return new value for {@code curLocalIdx} * @throws IOException */ private int emitLocalsAtAddress(int curLocalIdx) throws IOException { int sz = locals.size(); // TODO: Don't emit ends implied by starts. while ((curLocalIdx < sz) && (locals.get(curLocalIdx).getAddress() == address)) { LocalList.Entry entry = locals.get(curLocalIdx++); int reg = entry.getRegister(); LocalList.Entry prevEntry = lastEntryForReg[reg]; if (entry == prevEntry) { /* * Here we ignore locals entries for parameters, * which have already been represented and placed in the * lastEntryForReg array. */ continue; } // At this point we have a new entry one way or another. lastEntryForReg[reg] = entry; if (entry.isStart()) { if ((prevEntry != null) && entry.matches(prevEntry)) { /* * The previous local in this register has the same * name and type as the one being introduced now, so * use the more efficient "restart" form. */ if (prevEntry.isStart()) { /* * We should never be handed a start when a * a matching local is already active. */ throw new RuntimeException("shouldn't happen"); } emitLocalRestart(entry); } else { emitLocalStart(entry); } } else { /* * Only emit a local end if it is *not* due to a direct * replacement. Direct replacements imply an end of the * previous local in the same register. * * TODO: Make sure the runtime can deal with implied * local ends from category-2 interactions, and when so, * also stop emitting local ends for those cases. */ if (entry.getDisposition() != LocalList.Disposition.END_REPLACED) { emitLocalEnd(entry); } } } return curLocalIdx; } /** * Emits all positions that occur at the current {@code address} * * @param curPositionIdx Current index in sortedPositions * @param sortedPositions positions, sorted by ascending address * @return new value for {@code curPositionIdx} * @throws IOException */ private int emitPositionsAtAddress(int curPositionIdx, ArrayList sortedPositions) throws IOException { int positionsSz = sortedPositions.size(); while ((curPositionIdx < positionsSz) && (sortedPositions.get(curPositionIdx).getAddress() == address)) { emitPosition(sortedPositions.get(curPositionIdx++)); } return curPositionIdx; } /** * Emits the header sequence, which consists of LEB128-encoded initial * line number and string indicies for names of all non-"this" arguments. * * @param sortedPositions positions, sorted by ascending address * @param methodArgs local list entries for method argumens arguments, * in left-to-right order omitting "this" * @throws IOException */ private void emitHeader(ArrayList sortedPositions, ArrayList methodArgs) throws IOException { boolean annotate = (annotateTo != null) || (debugPrint != null); int mark = output.getCursor(); // Start by initializing the line number register. if (sortedPositions.size() > 0) { PositionList.Entry entry = sortedPositions.get(0); line = entry.getPosition().getLine(); } output.writeUleb128(line); if (annotate) { annotate(output.getCursor() - mark, "line_start: " + line); } int curParam = getParamBase(); // paramTypes will not include 'this' StdTypeList paramTypes = desc.getParameterTypes(); int szParamTypes = paramTypes.size(); /* * Initialize lastEntryForReg to have an initial * entry for the 'this' pointer. */ if (!isStatic) { for (LocalList.Entry arg : methodArgs) { if (curParam == arg.getRegister()) { lastEntryForReg[curParam] = arg; break; } } curParam++; } // Write out the number of parameter entries that will follow. mark = output.getCursor(); output.writeUleb128(szParamTypes); if (annotate) { annotate(output.getCursor() - mark, String.format("parameters_size: %04x", szParamTypes)); } /* * Then emit the string indicies of all the method parameters. * Note that 'this', if applicable, is excluded. */ for (int i = 0; i < szParamTypes; i++) { Type pt = paramTypes.get(i); LocalList.Entry found = null; mark = output.getCursor(); for (LocalList.Entry arg : methodArgs) { if (curParam == arg.getRegister()) { found = arg; if (arg.getSignature() != null) { /* * Parameters with signatures will be re-emitted * in complete as LOCAL_START_EXTENDED's below. */ emitStringIndex(null); } else { emitStringIndex(arg.getName()); } lastEntryForReg[curParam] = arg; break; } } if (found == null) { /* * Emit a null symbol for "unnamed." This is common * for, e.g., synthesized methods and inner-class * this$0 arguments. */ emitStringIndex(null); } if (annotate) { String parameterName = (found == null || found.getSignature() != null) ? "" : found.getName().toHuman(); annotate(output.getCursor() - mark, "parameter " + parameterName + " " + RegisterSpec.PREFIX + curParam); } curParam += pt.getCategory(); } /* * If anything emitted above has a type signature, emit it again as * a LOCAL_RESTART_EXTENDED */ for (LocalList.Entry arg : lastEntryForReg) { if (arg == null) { continue; } CstString signature = arg.getSignature(); if (signature != null) { emitLocalStartExtended(arg); } } } /** * Builds a list of position entries, sorted by ascending address. * * @return A sorted positions list */ private ArrayList buildSortedPositions() { int sz = (positions == null) ? 0 : positions.size(); ArrayList result = new ArrayList(sz); for (int i = 0; i < sz; i++) { result.add(positions.get(i)); } // Sort ascending by address. Collections.sort (result, new Comparator() { public int compare (PositionList.Entry a, PositionList.Entry b) { return a.getAddress() - b.getAddress(); } public boolean equals (Object obj) { return obj == this; } }); return result; } /** * Gets the register that begins the method's parameter range (including * the 'this' parameter for non-static methods). The range continues until * {@code regSize} * * @return register as noted above */ private int getParamBase() { return regSize - desc.getParameterTypes().getWordCount() - (isStatic? 0 : 1); } /** * Extracts method arguments from a locals list. These will be collected * from the input list and sorted by ascending register in the * returned list. * * @return list of non-{@code this} method argument locals, * sorted by ascending register */ private ArrayList extractMethodArguments() { ArrayList result = new ArrayList(desc.getParameterTypes().size()); int argBase = getParamBase(); BitSet seen = new BitSet(regSize - argBase); int sz = locals.size(); for (int i = 0; i < sz; i++) { LocalList.Entry e = locals.get(i); int reg = e.getRegister(); if (reg < argBase) { continue; } // only the lowest-start-address entry is included. if (seen.get(reg - argBase)) { continue; } seen.set(reg - argBase); result.add(e); } // Sort by ascending register. Collections.sort(result, new Comparator() { public int compare(LocalList.Entry a, LocalList.Entry b) { return a.getRegister() - b.getRegister(); } public boolean equals(Object obj) { return obj == this; } }); return result; } /** * Returns a string representation of this LocalList entry that is * appropriate for emitting as an annotation. * * @param e {@code non-null;} entry * @return {@code non-null;} annotation string */ private String entryAnnotationString(LocalList.Entry e) { StringBuilder sb = new StringBuilder(); sb.append(RegisterSpec.PREFIX); sb.append(e.getRegister()); sb.append(' '); CstString name = e.getName(); if (name == null) { sb.append("null"); } else { sb.append(name.toHuman()); } sb.append(' '); CstType type = e.getType(); if (type == null) { sb.append("null"); } else { sb.append(type.toHuman()); } CstString signature = e.getSignature(); if (signature != null) { sb.append(' '); sb.append(signature.toHuman()); } return sb.toString(); } /** * Emits a {@link DebugInfoConstants#DBG_RESTART_LOCAL DBG_RESTART_LOCAL} * sequence. * * @param entry entry associated with this restart * @throws IOException */ private void emitLocalRestart(LocalList.Entry entry) throws IOException { int mark = output.getCursor(); output.writeByte(DBG_RESTART_LOCAL); emitUnsignedLeb128(entry.getRegister()); if (annotateTo != null || debugPrint != null) { annotate(output.getCursor() - mark, String.format("%04x: +local restart %s", address, entryAnnotationString(entry))); } if (DEBUG) { System.err.println("emit local restart"); } } /** * Emits a string index as an unsigned LEB128. The actual value written * is shifted by 1, so that the '0' value is reserved for "null". The * null symbol is used in some cases by the parameter name list * at the beginning of the sequence. * * @param string {@code null-ok;} string to emit * @throws IOException */ private void emitStringIndex(CstString string) throws IOException { if ((string == null) || (file == null)) { output.writeUleb128(0); } else { output.writeUleb128( 1 + file.getStringIds().indexOf(string)); } if (DEBUG) { System.err.printf("Emit string %s\n", string == null ? "" : string.toQuoted()); } } /** * Emits a type index as an unsigned LEB128. The actual value written * is shifted by 1, so that the '0' value is reserved for "null". * * @param type {@code null-ok;} type to emit * @throws IOException */ private void emitTypeIndex(CstType type) throws IOException { if ((type == null) || (file == null)) { output.writeUleb128(0); } else { output.writeUleb128( 1 + file.getTypeIds().indexOf(type)); } if (DEBUG) { System.err.printf("Emit type %s\n", type == null ? "" : type.toHuman()); } } /** * Emits a {@link DebugInfoConstants#DBG_START_LOCAL DBG_START_LOCAL} or * {@link DebugInfoConstants#DBG_START_LOCAL_EXTENDED * DBG_START_LOCAL_EXTENDED} sequence. * * @param entry entry to emit * @throws IOException */ private void emitLocalStart(LocalList.Entry entry) throws IOException { if (entry.getSignature() != null) { emitLocalStartExtended(entry); return; } int mark = output.getCursor(); output.writeByte(DBG_START_LOCAL); emitUnsignedLeb128(entry.getRegister()); emitStringIndex(entry.getName()); emitTypeIndex(entry.getType()); if (annotateTo != null || debugPrint != null) { annotate(output.getCursor() - mark, String.format("%04x: +local %s", address, entryAnnotationString(entry))); } if (DEBUG) { System.err.println("emit local start"); } } /** * Emits a {@link DebugInfoConstants#DBG_START_LOCAL_EXTENDED * DBG_START_LOCAL_EXTENDED} sequence. * * @param entry entry to emit * @throws IOException */ private void emitLocalStartExtended(LocalList.Entry entry) throws IOException { int mark = output.getCursor(); output.writeByte(DBG_START_LOCAL_EXTENDED); emitUnsignedLeb128(entry.getRegister()); emitStringIndex(entry.getName()); emitTypeIndex(entry.getType()); emitStringIndex(entry.getSignature()); if (annotateTo != null || debugPrint != null) { annotate(output.getCursor() - mark, String.format("%04x: +localx %s", address, entryAnnotationString(entry))); } if (DEBUG) { System.err.println("emit local start"); } } /** * Emits a {@link DebugInfoConstants#DBG_END_LOCAL DBG_END_LOCAL} sequence. * * @param entry {@code entry non-null;} entry associated with end. * @throws IOException */ private void emitLocalEnd(LocalList.Entry entry) throws IOException { int mark = output.getCursor(); output.writeByte(DBG_END_LOCAL); output.writeUleb128(entry.getRegister()); if (annotateTo != null || debugPrint != null) { annotate(output.getCursor() - mark, String.format("%04x: -local %s", address, entryAnnotationString(entry))); } if (DEBUG) { System.err.println("emit local end"); } } /** * Emits the necessary byte sequences to emit the given position table * entry. This will typically be a single special opcode, although * it may also require DBG_ADVANCE_PC or DBG_ADVANCE_LINE. * * @param entry position entry to emit. * @throws IOException */ private void emitPosition(PositionList.Entry entry) throws IOException { SourcePosition pos = entry.getPosition(); int newLine = pos.getLine(); int newAddress = entry.getAddress(); int opcode; int deltaLines = newLine - line; int deltaAddress = newAddress - address; if (deltaAddress < 0) { throw new RuntimeException( "Position entries must be in ascending address order"); } if ((deltaLines < DBG_LINE_BASE) || (deltaLines > (DBG_LINE_BASE + DBG_LINE_RANGE -1))) { emitAdvanceLine(deltaLines); deltaLines = 0; } opcode = computeOpcode (deltaLines, deltaAddress); if ((opcode & ~0xff) > 0) { emitAdvancePc(deltaAddress); deltaAddress = 0; opcode = computeOpcode (deltaLines, deltaAddress); if ((opcode & ~0xff) > 0) { emitAdvanceLine(deltaLines); deltaLines = 0; opcode = computeOpcode (deltaLines, deltaAddress); } } output.writeByte(opcode); line += deltaLines; address += deltaAddress; if (annotateTo != null || debugPrint != null) { annotate(1, String.format("%04x: line %d", address, line)); } } /** * Computes a special opcode that will encode the given position change. * If the return value is > 0xff, then the request cannot be fulfilled. * Essentially the same as described in "DWARF Debugging Format Version 3" * section 6.2.5.1. * * @param deltaLines {@code >= DBG_LINE_BASE, <= DBG_LINE_BASE + * DBG_LINE_RANGE;} the line change to encode * @param deltaAddress {@code >= 0;} the address change to encode * @return {@code <= 0xff} if in range, otherwise parameters are out * of range */ private static int computeOpcode(int deltaLines, int deltaAddress) { if (deltaLines < DBG_LINE_BASE || deltaLines > (DBG_LINE_BASE + DBG_LINE_RANGE -1)) { throw new RuntimeException("Parameter out of range"); } return (deltaLines - DBG_LINE_BASE) + (DBG_LINE_RANGE * deltaAddress) + DBG_FIRST_SPECIAL; } /** * Emits an {@link DebugInfoConstants#DBG_ADVANCE_LINE DBG_ADVANCE_LINE} * sequence. * * @param deltaLines amount to change line number register by * @throws IOException */ private void emitAdvanceLine(int deltaLines) throws IOException { int mark = output.getCursor(); output.writeByte(DBG_ADVANCE_LINE); output.writeSleb128(deltaLines); line += deltaLines; if (annotateTo != null || debugPrint != null) { annotate(output.getCursor() - mark, String.format("line = %d", line)); } if (DEBUG) { System.err.printf("Emitting advance_line for %d\n", deltaLines); } } /** * Emits an {@link DebugInfoConstants#DBG_ADVANCE_PC DBG_ADVANCE_PC} * sequence. * * @param deltaAddress {@code >= 0;} amount to change program counter by * @throws IOException */ private void emitAdvancePc(int deltaAddress) throws IOException { int mark = output.getCursor(); output.writeByte(DBG_ADVANCE_PC); output.writeUleb128(deltaAddress); address += deltaAddress; if (annotateTo != null || debugPrint != null) { annotate(output.getCursor() - mark, String.format("%04x: advance pc", address)); } if (DEBUG) { System.err.printf("Emitting advance_pc for %d\n", deltaAddress); } } /** * Emits an unsigned LEB128 value. * * @param n {@code >= 0;} value to emit. Note that, although this can * represent integers larger than Integer.MAX_VALUE, we currently don't * allow that. * @throws IOException */ private void emitUnsignedLeb128(int n) throws IOException { // We'll never need the top end of the unsigned range anyway. if (n < 0) { throw new RuntimeException( "Signed value where unsigned required: " + n); } output.writeUleb128(n); } /** * Emits the {@link DebugInfoConstants#DBG_END_SEQUENCE DBG_END_SEQUENCE} * bytecode. */ private void emitEndSequence() { output.writeByte(DBG_END_SEQUENCE); if (annotateTo != null || debugPrint != null) { annotate(1, "end sequence"); } } }




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