sun.tools.tree

Class Vset

java.lang.Object

sun.tools.tree.Vset

All Implemented Interfaces:

Constants, RuntimeConstants

public final class Vset
extends java.lang.Object
implements Constants

WARNING: The contents of this source file are not part of any supported API. Code that depends on them does so at its own risk: they are subject to change or removal without notice.

Field Summary

Fields inherited from interface sun.tools.java.Constants

ABSTRACT, ACCM_CLASS, ACCM_FIELD, ACCM_INNERCLASS, ACCM_MEMBER, ACCM_METHOD, ADD, AND, ARRAY, ARRAYACCESS, ASGADD, ASGBITAND, ASGBITOR, ASGBITXOR, ASGDIV, ASGLSHIFT, ASGMUL, ASGREM, ASGRSHIFT, ASGSUB, ASGURSHIFT, ASSIGN, ATT_ALL, ATT_ALLCLASSES, ATT_CODE, BITAND, BITNOT, BITOR, BITXOR, BOOLEAN, BOOLEANVAL, BREAK, BYTE, BYTEVAL, CASE, CAST, CATCH, CHAR, CHARVAL, CLASS, COLON, COMMA, COMMENT, COND, CONST, CONTINUE, CONVERT, CS_BINARY, CS_CHECKED, CS_COMPILED, CS_NOTFOUND, CS_PARSED, CS_SOURCE, CS_UNDECIDED, CS_UNDEFINED, CT_BLOCK, CT_BRANCH_FALSE, CT_BRANCH_TRUE, CT_CASE, CT_FIKT_METHOD, CT_FIKT_RET, CT_FIRST_KIND, CT_LAST_KIND, CT_METHOD, CT_SWITH_WO_DEF, DEC, DECLARATION, DEFAULT, DIV, DO, DOUBLE, DOUBLEVAL, ELSE, EQ, ERROR, EXPR, EXPRESSION, EXTENDS, F_COVDATA, F_COVERAGE, F_DEBUG_LINES, F_DEBUG_SOURCE, F_DEBUG_VARS, F_DEPENDENCIES, F_DEPRECATION, F_DUMP, F_ERRORSREPORTED, F_OPT, F_OPT_INTERCLASS, F_PRINT_DEPENDENCIES, F_STRICTDEFAULT, F_VERBOSE, F_VERSION12, F_WARNINGS, FALSE, FIELD, FINAL, FINALLY, FLOAT, FLOATVAL, FOR, GE, GOTO, GT, idAppend, idClass, idClassInit, idClone, idCode, idConstantValue, idCoverageTable, idDeprecated, idDocumentation, IDENT, idExceptions, idFinallyReturnValue, idGetClass, idInit, idInnerClasses, idJavaIoSerializable, idJavaLang, idJavaLangClass, idJavaLangCloneable, idJavaLangError, idJavaLangException, idJavaLangObject, idJavaLangRuntimeException, idJavaLangString, idJavaLangStringBuffer, idJavaLangThrowable, idLength, idLineNumberTable, idLocalVariableTable, idNew, idNull, idSourceFile, idStar, idSuper, idSynthetic, idThis, idToString, idTYPE, idValueOf, IF, IMPLEMENTS, IMPORT, INC, INLINEMETHOD, INLINENEWINSTANCE, INLINERETURN, INSTANCEOF, INT, INTERFACE, INTVAL, LBRACE, LE, LENGTH, LONG, LONGVAL, LPAREN, LSHIFT, LSQBRACKET, LT, M_ABSTRACT, M_ANONYMOUS, M_DEPRECATED, M_FINAL, M_INLINEABLE, M_INTERFACE, M_LOCAL, M_NATIVE, M_PRIVATE, M_PROTECTED, M_PUBLIC, M_STATIC, M_STRICTFP, M_SYNCHRONIZED, M_SYNTHETIC, M_TRANSIENT, M_VOLATILE, MAXFILESIZE, MAXLINENUMBER, METHOD, MM_CLASS, MM_FIELD, MM_MEMBER, MM_METHOD, MUL, NATIVE, NE, NEG, NEW, NEWARRAY, NEWFROMNAME, NEWINSTANCE, NOT, NULL, opNames, opPrecedence, OR, PACKAGE, paraDeprecated, POS, POSTDEC, POSTINC, PREDEC, prefixAccess, prefixArray, prefixClass, prefixLoc, prefixThis, prefixVal, PREINC, PRIVATE, PROTECTED, PUBLIC, QUESTIONMARK, RBRACE, REM, RETURN, RPAREN, RSHIFT, RSQBRACKET, SEMICOLON, SHORT, SHORTVAL, SIG_INNERCLASS, SIGC_INNERCLASS, STAT, STATIC, STRICTFP, STRINGVAL, SUB, SUPER, SWITCH, SYNCHRONIZED, TC_ARRAY, TC_BOOLEAN, TC_BYTE, TC_CHAR, TC_CLASS, TC_DOUBLE, TC_ERROR, TC_FLOAT, TC_INT, TC_LONG, TC_METHOD, TC_NULL, TC_SHORT, TC_VOID, THIS, THROW, THROWS, TM_ARRAY, TM_BOOLEAN, TM_BYTE, TM_CHAR, TM_CLASS, TM_DOUBLE, TM_ERROR, TM_FLOAT, TM_INT, TM_INT32, TM_INTEGER, TM_LONG, TM_METHOD, TM_NULL, TM_NUM32, TM_NUM64, TM_NUMBER, TM_REAL, TM_REFERENCE, TM_SHORT, TM_VOID, tracing, TRANSIENT, TRUE, TRY, TYPE, URSHIFT, VARDECLARATION, VOID, VOLATILE, WHEREOFFSETBITS, WHILE

Fields inherited from interface sun.tools.java.RuntimeConstants

ACC_ABSTRACT, ACC_FINAL, ACC_INTERFACE, ACC_NATIVE, ACC_PRIVATE, ACC_PROTECTED, ACC_PUBLIC, ACC_STATIC, ACC_STRICT, ACC_SUPER, ACC_SYNCHRONIZED, ACC_TRANSIENT, ACC_VOLATILE, CONSTANT_CLASS, CONSTANT_DOUBLE, CONSTANT_FIELD, CONSTANT_FLOAT, CONSTANT_INTEGER, CONSTANT_INTERFACEMETHOD, CONSTANT_INVOKEDYNAMIC, CONSTANT_LONG, CONSTANT_METHOD, CONSTANT_METHODHANDLE, CONSTANT_METHODTYPE, CONSTANT_NAMEANDTYPE, CONSTANT_STRING, CONSTANT_UNICODE, CONSTANT_UTF8, JAVA_DEFAULT_MINOR_VERSION, JAVA_DEFAULT_VERSION, JAVA_MAGIC, JAVA_MAX_SUPPORTED_MINOR_VERSION, JAVA_MAX_SUPPORTED_VERSION, JAVA_MIN_SUPPORTED_VERSION, opc_aaload, opc_aastore, opc_aconst_null, opc_aload, opc_aload_0, opc_aload_1, opc_aload_2, opc_aload_3, opc_anewarray, opc_areturn, opc_arraylength, opc_astore, opc_astore_0, opc_astore_1, opc_astore_2, opc_astore_3, opc_athrow, opc_baload, opc_bastore, opc_bipush, opc_breakpoint, opc_caload, opc_castore, opc_checkcast, opc_d2f, opc_d2i, opc_d2l, opc_dadd, opc_daload, opc_dastore, opc_dcmpg, opc_dcmpl, opc_dconst_0, opc_dconst_1, opc_ddiv, opc_dead, opc_dload, opc_dload_0, opc_dload_1, opc_dload_2, opc_dload_3, opc_dmul, opc_dneg, opc_drem, opc_dreturn, opc_dstore, opc_dstore_0, opc_dstore_1, opc_dstore_2, opc_dstore_3, opc_dsub, opc_dup, opc_dup_x1, opc_dup_x2, opc_dup2, opc_dup2_x1, opc_dup2_x2, opc_f2d, opc_f2i, opc_f2l, opc_fadd, opc_faload, opc_fastore, opc_fcmpg, opc_fcmpl, opc_fconst_0, opc_fconst_1, opc_fconst_2, opc_fdiv, opc_fload, opc_fload_0, opc_fload_1, opc_fload_2, opc_fload_3, opc_fmul, opc_fneg, opc_frem, opc_freturn, opc_fstore, opc_fstore_0, opc_fstore_1, opc_fstore_2, opc_fstore_3, opc_fsub, opc_getfield, opc_getstatic, opc_goto, opc_goto_w, opc_i2b, opc_i2c, opc_i2d, opc_i2f, opc_i2l, opc_i2s, opc_iadd, opc_iaload, opc_iand, opc_iastore, opc_iconst_0, opc_iconst_1, opc_iconst_2, opc_iconst_3, opc_iconst_4, opc_iconst_5, opc_iconst_m1, opc_idiv, opc_if_acmpeq, opc_if_acmpne, opc_if_icmpeq, opc_if_icmpge, opc_if_icmpgt, opc_if_icmple, opc_if_icmplt, opc_if_icmpne, opc_ifeq, opc_ifge, opc_ifgt, opc_ifle, opc_iflt, opc_ifne, opc_ifnonnull, opc_ifnull, opc_iinc, opc_iload, opc_iload_0, opc_iload_1, opc_iload_2, opc_iload_3, opc_imul, opc_ineg, opc_instanceof, opc_invokedynamic, opc_invokeinterface, opc_invokespecial, opc_invokestatic, opc_invokevirtual, opc_ior, opc_irem, opc_ireturn, opc_ishl, opc_ishr, opc_istore, opc_istore_0, opc_istore_1, opc_istore_2, opc_istore_3, opc_isub, opc_iushr, opc_ixor, opc_jsr, opc_jsr_w, opc_l2d, opc_l2f, opc_l2i, opc_label, opc_ladd, opc_laload, opc_land, opc_lastore, opc_lcmp, opc_lconst_0, opc_lconst_1, opc_ldc, opc_ldc_w, opc_ldc2_w, opc_ldiv, opc_lload, opc_lload_0, opc_lload_1, opc_lload_2, opc_lload_3, opc_lmul, opc_lneg, opc_lookupswitch, opc_lor, opc_lrem, opc_lreturn, opc_lshl, opc_lshr, opc_lstore, opc_lstore_0, opc_lstore_1, opc_lstore_2, opc_lstore_3, opc_lsub, opc_lushr, opc_lxor, opc_monitorenter, opc_monitorexit, opc_multianewarray, opc_new, opc_newarray, opc_nop, opc_pop, opc_pop2, opc_putfield, opc_putstatic, opc_ret, opc_return, opc_saload, opc_sastore, opc_sipush, opc_swap, opc_tableswitch, opc_try, opc_wide, opcLengths, opcNames, SIG_ARRAY, SIG_BOOLEAN, SIG_BYTE, SIG_CHAR, SIG_CLASS, SIG_DOUBLE, SIG_ENDCLASS, SIG_ENDMETHOD, SIG_FLOAT, SIG_INT, SIG_LONG, SIG_METHOD, SIG_PACKAGE, SIG_SHORT, SIG_VOID, SIGC_ARRAY, SIGC_BOOLEAN, SIGC_BYTE, SIGC_CHAR, SIGC_CLASS, SIGC_DOUBLE, SIGC_ENDCLASS, SIGC_ENDMETHOD, SIGC_FLOAT, SIGC_INT, SIGC_LONG, SIGC_METHOD, SIGC_PACKAGE, SIGC_SHORT, SIGC_VOID, T_BOOLEAN, T_BYTE, T_CHAR, T_CLASS, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_SHORT

Constructor Summary

Constructors

Constructor and Description
Vset() Create an empty Vset.

Method Summary

Methods

Modifier and Type	Method and Description
Vset	addDAandJoinDU(Vset other) Add in the definite assignment bits of another vset, but join the definite unassignment bits.
Vset	addVar(int varNumber) Note that a var is definitely assigned.
Vset	addVarUnassigned(int varNumber) Note that a var is definitely un-assigned.
Vset	clearDeadEnd() Replace canonical DEAD_END with a distinct but equivalent Vset.
Vset	clearVar(int varNumber) Retract any assertion about the var.
Vset	copy() Create an copy of the given Vset.
static Vset	firstDAandSecondDU(Vset sourceDA, Vset sourceDU) Construct a vset consisting of the DA bits of the first argument and the DU bits of the second argument.
boolean	isDeadEnd() Ask if this is a vset for a dead end.
boolean	isReallyDeadEnd() Ask if this is a vset for a dead end.
Vset	join(Vset other) Join with another vset.
Vset	removeAdditionalVars(int varNumber) Remove variables from the vset that are no longer part of a context.
boolean	testVar(int varNumber) Ask if a var is definitely assigned.
boolean	testVarUnassigned(int varNumber) Ask if a var is definitely un-assigned.
java.lang.String	toString()
int	varLimit() Return one larger than the highest bit set.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Vset

public Vset()

Create an empty Vset.

Method Detail

copy

public Vset copy()

Create an copy of the given Vset. (However, DEAD_END simply returns itself.)

isDeadEnd

public boolean isDeadEnd()

Ask if this is a vset for a dead end. Answer true only for the canonical dead-end, DEAD_END. A canonical dead-end is produced only as a result of a statement that cannot complete normally, as specified by the JLS. Due to the special-case rules for if-then and if-then-else, this may fail to detect actual unreachable code that could easily be identified.

isReallyDeadEnd

public boolean isReallyDeadEnd()

Ask if this is a vset for a dead end. Answer true for any dead-end. Since 'clearDeadEnd' has no effect on this predicate, if-then and if-then-else are handled in the more 'obvious' and precise way. This predicate is to be preferred for dead code elimination purposes. (Presently used in workaround for bug 4173473 in MethodExpression.java)

clearDeadEnd

public Vset clearDeadEnd()

Replace canonical DEAD_END with a distinct but equivalent Vset. The bits are unaltered, but the result does not answer true to 'isDeadEnd'.

Used mostly for error recovery, but see 'IfStatement.check', where it is used to implement the special-case treatment of statement reachability for such statements.

testVar

public boolean testVar(int varNumber)

Ask if a var is definitely assigned.

testVarUnassigned

public boolean testVarUnassigned(int varNumber)

Ask if a var is definitely un-assigned. (This is not just the negation of testVar: It's possible for neither to be true.)

addVar

public Vset addVar(int varNumber)

Note that a var is definitely assigned. (Side-effecting.)

addVarUnassigned

public Vset addVarUnassigned(int varNumber)

Note that a var is definitely un-assigned. (Side-effecting.)

clearVar

public Vset clearVar(int varNumber)

Retract any assertion about the var. This operation is ineffective on a dead-end. (Side-effecting.)

join

public Vset join(Vset other)

Join with another vset. This is set intersection. (Side-effecting.)

addDAandJoinDU

public Vset addDAandJoinDU(Vset other)

Add in the definite assignment bits of another vset, but join the definite unassignment bits. This unusual operation is used only for 'finally' blocks. The original vset 'this' is destroyed by this operation. (Part of fix for 4068688.)

firstDAandSecondDU

public static Vset firstDAandSecondDU(Vset sourceDA,
                      Vset sourceDU)

Construct a vset consisting of the DA bits of the first argument and the DU bits of the second argument. This is a higly unusual operation, as it implies a case where the flowgraph for DA analysis differs from that for DU analysis. It is only needed for analysing 'try' blocks. The result is a dead-end iff the first argument is dead-end. (Part of fix for 4068688.)

removeAdditionalVars

public Vset removeAdditionalVars(int varNumber)

Remove variables from the vset that are no longer part of a context. Zeroes are stored past varNumber. (Side-effecting.)

However, if this is a dead end, keep it so. That is, leave an infinite tail of bits set.

varLimit

public int varLimit()

Return one larger than the highest bit set.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object