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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
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package jdk.vm.ci.code;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Map;

import jdk.vm.ci.meta.JavaType;
import jdk.vm.ci.meta.MetaUtil;
import jdk.vm.ci.meta.ResolvedJavaMethod;
import jdk.vm.ci.meta.Signature;

Miscellaneous collection of utility methods used by jdk.vm.ci.code and its clients.
/** * Miscellaneous collection of utility methods used by {@code jdk.vm.ci.code} and its clients. */
public class CodeUtil { public static final String NEW_LINE = String.format("%n"); public static final int K = 1024; public static final int M = 1024 * 1024; public static boolean isOdd(int n) { return (n & 1) == 1; } public static boolean isEven(int n) { return (n & 1) == 0; }
Checks whether the specified integer is a power of two.
Params:
  • val – the value to check
Returns:true if the value is a power of two; false otherwise
/** * Checks whether the specified integer is a power of two. * * @param val the value to check * @return {@code true} if the value is a power of two; {@code false} otherwise */
public static boolean isPowerOf2(int val) { return val > 0 && (val & val - 1) == 0; }
Checks whether the specified long is a power of two.
Params:
  • val – the value to check
Returns:true if the value is a power of two; false otherwise
/** * Checks whether the specified long is a power of two. * * @param val the value to check * @return {@code true} if the value is a power of two; {@code false} otherwise */
public static boolean isPowerOf2(long val) { return val > 0 && (val & val - 1) == 0; }
Computes the log (base 2) of the specified integer, rounding down. (E.g log2(8) = 3, log2(21) = 4 )
Params:
  • val – the value
Returns:the log base 2 of the value
/** * Computes the log (base 2) of the specified integer, rounding down. (E.g {@code log2(8) = 3}, * {@code log2(21) = 4} ) * * @param val the value * @return the log base 2 of the value */
public static int log2(int val) { assert val > 0; return (Integer.SIZE - 1) - Integer.numberOfLeadingZeros(val); }
Computes the log (base 2) of the specified long, rounding down. (E.g log2(8) = 3, log2(21) = 4)
Params:
  • val – the value
Returns:the log base 2 of the value
/** * Computes the log (base 2) of the specified long, rounding down. (E.g {@code log2(8) = 3}, * {@code log2(21) = 4}) * * @param val the value * @return the log base 2 of the value */
public static int log2(long val) { assert val > 0; return (Long.SIZE - 1) - Long.numberOfLeadingZeros(val); }
Narrow an integer value to a given bit width, and return the result as a signed long.
Params:
  • value – the value
  • resultBits – the result bit width
Returns:value interpreted as resultBits bit number, encoded as signed long
/** * Narrow an integer value to a given bit width, and return the result as a signed long. * * @param value the value * @param resultBits the result bit width * @return {@code value} interpreted as {@code resultBits} bit number, encoded as signed long */
public static long narrow(long value, int resultBits) { long ret = value & mask(resultBits); return signExtend(ret, resultBits); }
Sign extend an integer.
Params:
  • value – the input value
  • inputBits – the bit width of the input value
Returns:a signed long with the same value as the signed inputBits-bit number value
/** * Sign extend an integer. * * @param value the input value * @param inputBits the bit width of the input value * @return a signed long with the same value as the signed {@code inputBits}-bit number * {@code value} */
public static long signExtend(long value, int inputBits) { if (inputBits < 64) { if ((value >>> (inputBits - 1) & 1) == 1) { return value | (-1L << inputBits); } else { return value & ~(-1L << inputBits); } } else { return value; } }
Zero extend an integer.
Params:
  • value – the input value
  • inputBits – the bit width of the input value
Returns:an unsigned long with the same value as the unsigned inputBits-bit number value
/** * Zero extend an integer. * * @param value the input value * @param inputBits the bit width of the input value * @return an unsigned long with the same value as the unsigned {@code inputBits}-bit number * {@code value} */
public static long zeroExtend(long value, int inputBits) { if (inputBits < 64) { return value & ~(-1L << inputBits); } else { return value; } }
Convert an integer to long.
Params:
  • value – the input value
  • inputBits – the bit width of the input value
  • unsigned – whether the values should be interpreted as signed or unsigned
Returns:a long with the same value as the inputBits-bit number value
/** * Convert an integer to long. * * @param value the input value * @param inputBits the bit width of the input value * @param unsigned whether the values should be interpreted as signed or unsigned * @return a long with the same value as the {@code inputBits}-bit number {@code value} */
public static long convert(long value, int inputBits, boolean unsigned) { if (unsigned) { return zeroExtend(value, inputBits); } else { return signExtend(value, inputBits); } }
Get a bitmask with the low bits bit set and the high 64 - bits bit clear.
/** * Get a bitmask with the low {@code bits} bit set and the high {@code 64 - bits} bit clear. */
public static long mask(int bits) { assert 0 <= bits && bits <= 64; if (bits == 64) { return 0xffffffffffffffffL; } else { return (1L << bits) - 1; } }
Get the minimum value representable in a bits bit signed integer.
/** * Get the minimum value representable in a {@code bits} bit signed integer. */
public static long minValue(int bits) { assert 0 < bits && bits <= 64; return -1L << (bits - 1); }
Get the maximum value representable in a bits bit signed integer.
/** * Get the maximum value representable in a {@code bits} bit signed integer. */
public static long maxValue(int bits) { assert 0 < bits && bits <= 64; return mask(bits - 1); }
Formats the values in a frame as a tabulated string.
Params:
  • frame –
Returns:the values in frame as a tabulated string
/** * Formats the values in a frame as a tabulated string. * * @param frame * @return the values in {@code frame} as a tabulated string */
public static String tabulateValues(BytecodeFrame frame) { int cols = Math.max(frame.numLocals, Math.max(frame.numStack, frame.numLocks)); assert cols > 0; ArrayList<Object> cells = new ArrayList<>(); cells.add(""); for (int i = 0; i < cols; i++) { cells.add(i); } cols++; if (frame.numLocals != 0) { cells.add("locals:"); cells.addAll(Arrays.asList(frame.values).subList(0, frame.numLocals)); cells.addAll(Collections.nCopies(cols - frame.numLocals - 1, "")); } if (frame.numStack != 0) { cells.add("stack:"); cells.addAll(Arrays.asList(frame.values).subList(frame.numLocals, frame.numLocals + frame.numStack)); cells.addAll(Collections.nCopies(cols - frame.numStack - 1, "")); } if (frame.numLocks != 0) { cells.add("locks:"); cells.addAll(Arrays.asList(frame.values).subList(frame.numLocals + frame.numStack, frame.values.length)); cells.addAll(Collections.nCopies(cols - frame.numLocks - 1, "")); } Object[] cellArray = cells.toArray(); for (int i = 0; i < cellArray.length; i++) { if ((i % cols) != 0) { cellArray[i] = "|" + cellArray[i]; } } return CodeUtil.tabulate(cellArray, cols, 1, 1); }
Formats a given table as a string. The value of each cell is produced by String.valueOf(Object).
Params:
  • cells – the cells of the table in row-major order
  • cols – the number of columns per row
  • lpad – the number of space padding inserted before each formatted cell value
  • rpad – the number of space padding inserted after each formatted cell value
Returns:a string with one line per row and each column left-aligned
/** * Formats a given table as a string. The value of each cell is produced by * {@link String#valueOf(Object)}. * * @param cells the cells of the table in row-major order * @param cols the number of columns per row * @param lpad the number of space padding inserted before each formatted cell value * @param rpad the number of space padding inserted after each formatted cell value * @return a string with one line per row and each column left-aligned */
public static String tabulate(Object[] cells, int cols, int lpad, int rpad) { int rows = (cells.length + (cols - 1)) / cols; int[] colWidths = new int[cols]; for (int col = 0; col < cols; col++) { for (int row = 0; row < rows; row++) { int index = col + (row * cols); if (index < cells.length) { Object cell = cells[index]; colWidths[col] = Math.max(colWidths[col], String.valueOf(cell).length()); } } } StringBuilder sb = new StringBuilder(); String nl = NEW_LINE; for (int row = 0; row < rows; row++) { for (int col = 0; col < cols; col++) { int index = col + (row * cols); if (index < cells.length) { for (int i = 0; i < lpad; i++) { sb.append(' '); } Object cell = cells[index]; String s = String.valueOf(cell); int w = s.length(); sb.append(s); while (w < colWidths[col]) { sb.append(' '); w++; } for (int i = 0; i < rpad; i++) { sb.append(' '); } } } sb.append(nl); } return sb.toString(); }
Appends a formatted code position to a StringBuilder.
Params:
  • sb – the StringBuilder to append to
  • pos – the code position to format and append to sb
Returns:the value of sb
/** * Appends a formatted code position to a {@link StringBuilder}. * * @param sb the {@link StringBuilder} to append to * @param pos the code position to format and append to {@code sb} * @return the value of {@code sb} */
public static StringBuilder append(StringBuilder sb, BytecodePosition pos) { MetaUtil.appendLocation(sb.append("at "), pos.getMethod(), pos.getBCI()); if (pos.getCaller() != null) { sb.append(NEW_LINE); append(sb, pos.getCaller()); } return sb; }
Appends a formatted frame to a StringBuilder.
Params:
  • sb – the StringBuilder to append to
  • frame – the frame to format and append to sb
Returns:the value of sb
/** * Appends a formatted frame to a {@link StringBuilder}. * * @param sb the {@link StringBuilder} to append to * @param frame the frame to format and append to {@code sb} * @return the value of {@code sb} */
public static StringBuilder append(StringBuilder sb, BytecodeFrame frame) { MetaUtil.appendLocation(sb.append("at "), frame.getMethod(), frame.getBCI()); assert sb.charAt(sb.length() - 1) == ']'; sb.deleteCharAt(sb.length() - 1); sb.append(", duringCall: ").append(frame.duringCall).append(", rethrow: ").append(frame.rethrowException).append(']'); if (frame.values != null && frame.values.length > 0) { sb.append(NEW_LINE); String table = tabulateValues(frame); String[] rows = table.split(NEW_LINE); for (int i = 0; i < rows.length; i++) { String row = rows[i]; if (!row.trim().isEmpty()) { sb.append(" ").append(row); if (i != rows.length - 1) { sb.append(NEW_LINE); } } } } if (frame.caller() != null) { sb.append(NEW_LINE); append(sb, frame.caller()); } else if (frame.getCaller() != null) { sb.append(NEW_LINE); append(sb, frame.getCaller()); } return sb; } public interface RefMapFormatter { String formatStackSlot(int frameRefMapIndex); }
Formats a location present in a reference map.
/** * Formats a location present in a reference map. */
public static class DefaultRefMapFormatter implements RefMapFormatter {
The size of a stack slot.
/** * The size of a stack slot. */
public final int slotSize;
The register used as the frame pointer.
/** * The register used as the frame pointer. */
public final Register fp;
The offset (in bytes) from the slot pointed to by fp to the slot corresponding to bit 0 in the frame reference map.
/** * The offset (in bytes) from the slot pointed to by {@link #fp} to the slot corresponding * to bit 0 in the frame reference map. */
public final int refMapToFPOffset; public DefaultRefMapFormatter(int slotSize, Register fp, int refMapToFPOffset) { this.slotSize = slotSize; this.fp = fp; this.refMapToFPOffset = refMapToFPOffset; } @Override public String formatStackSlot(int frameRefMapIndex) { int refMapOffset = frameRefMapIndex * slotSize; int fpOffset = refMapOffset + refMapToFPOffset; if (fpOffset >= 0) { return fp + "+" + fpOffset; } return fp.name + fpOffset; } } public static class NumberedRefMapFormatter implements RefMapFormatter { public String formatStackSlot(int frameRefMapIndex) { return "s" + frameRefMapIndex; } public String formatRegister(int regRefMapIndex) { return "r" + regRefMapIndex; } }
Appends a formatted debug info to a StringBuilder.
Params:
  • sb – the StringBuilder to append to
  • info – the debug info to format and append to sb
Returns:the value of sb
/** * Appends a formatted debug info to a {@link StringBuilder}. * * @param sb the {@link StringBuilder} to append to * @param info the debug info to format and append to {@code sb} * @return the value of {@code sb} */
public static StringBuilder append(StringBuilder sb, DebugInfo info, RefMapFormatter formatterArg) { RefMapFormatter formatter = formatterArg; if (formatter == null) { formatter = new NumberedRefMapFormatter(); } String nl = NEW_LINE; ReferenceMap refMap = info.getReferenceMap(); if (refMap != null) { sb.append(refMap.toString()); } RegisterSaveLayout calleeSaveInfo = info.getCalleeSaveInfo(); if (calleeSaveInfo != null) { sb.append("callee-save-info:").append(nl); Map<Integer, Register> map = calleeSaveInfo.slotsToRegisters(true); for (Map.Entry<Integer, Register> e : map.entrySet()) { sb.append(" ").append(e.getValue()).append(" -> ").append(formatter.formatStackSlot(e.getKey())).append(nl); } } BytecodeFrame frame = info.frame(); if (frame != null) { append(sb, frame); } else if (info.getBytecodePosition() != null) { append(sb, info.getBytecodePosition()); } return sb; }
Create a calling convention from a ResolvedJavaMethod.
/** * Create a calling convention from a {@link ResolvedJavaMethod}. */
public static CallingConvention getCallingConvention(CodeCacheProvider codeCache, CallingConvention.Type type, ResolvedJavaMethod method, ValueKindFactory<?> valueKindFactory) { Signature sig = method.getSignature(); JavaType retType = sig.getReturnType(null); int sigCount = sig.getParameterCount(false); JavaType[] argTypes; int argIndex = 0; if (!method.isStatic()) { argTypes = new JavaType[sigCount + 1]; argTypes[argIndex++] = method.getDeclaringClass(); } else { argTypes = new JavaType[sigCount]; } for (int i = 0; i < sigCount; i++) { argTypes[argIndex++] = sig.getParameterType(i, null); } RegisterConfig registerConfig = codeCache.getRegisterConfig(); return registerConfig.getCallingConvention(type, retType, argTypes, valueKindFactory); } }