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AstTranslator.java
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AstTranslator.java
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/*
* Copyright (c) 2002 - 2006 IBM Corporation.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*/
package com.ibm.wala.cast.ir.translator;
import com.ibm.wala.cast.ir.ssa.AssignInstruction;
import com.ibm.wala.cast.ir.ssa.AstAssertInstruction;
import com.ibm.wala.cast.ir.ssa.AstEchoInstruction;
import com.ibm.wala.cast.ir.ssa.AstGlobalRead;
import com.ibm.wala.cast.ir.ssa.AstGlobalWrite;
import com.ibm.wala.cast.ir.ssa.AstInstructionFactory;
import com.ibm.wala.cast.ir.ssa.AstIsDefinedInstruction;
import com.ibm.wala.cast.ir.ssa.AstLexicalAccess.Access;
import com.ibm.wala.cast.ir.ssa.AstLexicalRead;
import com.ibm.wala.cast.ir.ssa.AstLexicalWrite;
import com.ibm.wala.cast.ir.ssa.AstYieldInstruction;
import com.ibm.wala.cast.ir.ssa.CAstBinaryOp;
import com.ibm.wala.cast.ir.ssa.CAstUnaryOp;
import com.ibm.wala.cast.ir.ssa.EachElementGetInstruction;
import com.ibm.wala.cast.ir.ssa.EachElementHasNextInstruction;
import com.ibm.wala.cast.ir.ssa.SSAConversion;
import com.ibm.wala.cast.loader.AstMethod;
import com.ibm.wala.cast.loader.AstMethod.DebuggingInformation;
import com.ibm.wala.cast.loader.AstMethod.LexicalInformation;
import com.ibm.wala.cast.loader.CAstAbstractLoader;
import com.ibm.wala.cast.tree.CAstControlFlowMap;
import com.ibm.wala.cast.tree.CAstEntity;
import com.ibm.wala.cast.tree.CAstNode;
import com.ibm.wala.cast.tree.CAstSourcePositionMap;
import com.ibm.wala.cast.tree.CAstSourcePositionMap.Position;
import com.ibm.wala.cast.tree.CAstSymbol;
import com.ibm.wala.cast.tree.CAstType;
import com.ibm.wala.cast.tree.impl.AbstractSourcePosition;
import com.ibm.wala.cast.tree.impl.CAstImpl;
import com.ibm.wala.cast.tree.impl.CAstOperator;
import com.ibm.wala.cast.tree.impl.CAstSymbolImpl;
import com.ibm.wala.cast.tree.impl.CAstSymbolImplBase;
import com.ibm.wala.cast.tree.rewrite.CAstCloner;
import com.ibm.wala.cast.tree.rewrite.CAstRewriter;
import com.ibm.wala.cast.tree.visit.CAstVisitor;
import com.ibm.wala.cast.types.AstTypeReference;
import com.ibm.wala.cast.util.CAstPrinter;
import com.ibm.wala.cast.util.SourceBuffer;
import com.ibm.wala.cfg.AbstractCFG;
import com.ibm.wala.cfg.IBasicBlock;
import com.ibm.wala.classLoader.CallSiteReference;
import com.ibm.wala.classLoader.IClassLoader;
import com.ibm.wala.classLoader.IMethod;
import com.ibm.wala.classLoader.ModuleEntry;
import com.ibm.wala.ipa.callgraph.CGNode;
import com.ibm.wala.shrikeBT.BinaryOpInstruction;
import com.ibm.wala.shrikeBT.ConditionalBranchInstruction;
import com.ibm.wala.shrikeBT.IBinaryOpInstruction;
import com.ibm.wala.shrikeBT.IConditionalBranchInstruction;
import com.ibm.wala.shrikeBT.IUnaryOpInstruction;
import com.ibm.wala.shrikeBT.ShiftInstruction;
import com.ibm.wala.ssa.SSAAbstractInvokeInstruction;
import com.ibm.wala.ssa.SSAConditionalBranchInstruction;
import com.ibm.wala.ssa.SSAGetCaughtExceptionInstruction;
import com.ibm.wala.ssa.SSAGotoInstruction;
import com.ibm.wala.ssa.SSAInstruction;
import com.ibm.wala.ssa.SSAInstructionFactory;
import com.ibm.wala.ssa.SSAMonitorInstruction;
import com.ibm.wala.ssa.SSAThrowInstruction;
import com.ibm.wala.ssa.SymbolTable;
import com.ibm.wala.types.FieldReference;
import com.ibm.wala.types.TypeName;
import com.ibm.wala.types.TypeReference;
import com.ibm.wala.util.collections.HashMapFactory;
import com.ibm.wala.util.collections.HashSetFactory;
import com.ibm.wala.util.collections.Iterator2Iterable;
import com.ibm.wala.util.collections.MapUtil;
import com.ibm.wala.util.collections.Pair;
import com.ibm.wala.util.debug.Assertions;
import com.ibm.wala.util.debug.UnimplementedError;
import com.ibm.wala.util.graph.impl.SparseNumberedGraph;
import com.ibm.wala.util.graph.traverse.DFS;
import com.ibm.wala.util.intset.IntSet;
import com.ibm.wala.util.intset.IntSetUtil;
import com.ibm.wala.util.intset.MutableIntSet;
import com.ibm.wala.util.strings.Atom;
import com.ibm.wala.util.warnings.Warning;
import java.io.IOException;
import java.io.Reader;
import java.net.URL;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.SortedSet;
import java.util.function.Function;
/**
* Common code to translate CAst to IR. Must be specialized by each language to handle semantics
* appropriately.
*/
public abstract class AstTranslator extends CAstVisitor<AstTranslator.WalkContext>
implements ArrayOpHandler, TranslatorToIR {
/**
* does the language care about using type-appropriate default values? For Java, the answer is yes
* (ints should get a default value of 0, null for pointers, etc.). For JavaScript, the answer is
* no, as any variable can hold the value 'undefined'.
*/
protected abstract boolean useDefaultInitValues();
/** can lexical reads / writes access globals? */
protected abstract boolean treatGlobalsAsLexicallyScoped();
protected boolean topLevelFunctionsInGlobalScope() {
return true;
}
/**
* for a block that catches all exceptions, what is the root exception type that it can catch?
* E.g., for Java, java.lang.Throwable
*/
protected abstract TypeReference defaultCatchType();
protected abstract TypeReference makeType(CAstType type);
/**
* define a new (presumably nested) type. return true if type was successfully defined, false
* otherwise
*/
protected abstract boolean defineType(CAstEntity type, WalkContext wc);
/** declare a new function, represented by N */
protected abstract void declareFunction(CAstEntity N, WalkContext context);
/** fully define a function. invoked after all the code of the function has been processed */
protected abstract void defineFunction(
CAstEntity N,
WalkContext definingContext,
AbstractCFG<SSAInstruction, ? extends IBasicBlock<SSAInstruction>> cfg,
SymbolTable symtab,
boolean hasCatchBlock,
Map<IBasicBlock<SSAInstruction>, TypeReference[]> catchTypes,
boolean hasMonitorOp,
AstLexicalInformation lexicalInfo,
DebuggingInformation debugInfo);
/** define a new field fieldEntity within topEntity */
protected abstract void defineField(
CAstEntity topEntity, WalkContext context, CAstEntity fieldEntity);
/** create the language-appropriate name for f */
protected abstract String composeEntityName(WalkContext parent, CAstEntity f);
/** generate IR for a CAst throw expression, updating context.cfg() */
protected abstract void doThrow(WalkContext context, int exception);
/** generate IR for a CAst array read, updating context.cfg() */
@Override
public abstract void doArrayRead(
WalkContext context, int result, int arrayValue, CAstNode arrayRef, int[] dimValues);
/** generate IR for a CAst array write, updating context.cfg() */
@Override
public abstract void doArrayWrite(
WalkContext context, int arrayValue, CAstNode arrayRef, int[] dimValues, int rval);
/** generate IR for a CAst field read, updating context.cfg() */
protected abstract void doFieldRead(
WalkContext context, int result, int receiver, CAstNode elt, CAstNode parent);
/** generate IR for a CAst field write, updating context.cfg() */
protected abstract void doFieldWrite(
WalkContext context, int receiver, CAstNode elt, CAstNode parent, int rval);
/** generate IR for a CAst function expression, updating context.cfg() */
protected abstract void doMaterializeFunction(
CAstNode node, WalkContext context, int result, int exception, CAstEntity fn);
/** generate IR for a CAst new expression, updating context.cfg() */
protected abstract void doNewObject(
WalkContext context, CAstNode newNode, int result, Object type, int[] arguments);
/** generate IR for a CAst method call expression, updating context.cfg() */
protected abstract void doCall(
WalkContext context,
CAstNode call,
int result,
int exception,
CAstNode name,
int receiver,
int[] arguments);
/** the most-general type for the language being translated */
protected abstract CAstType topType();
/** the most-general exception type for the language being translated */
protected abstract CAstType exceptionType();
/** lift variable declarations for lexical scoping purposes? */
protected boolean liftDeclarationsForLexicalScoping() {
return false;
}
/** used to generate instructions for array operations; defaults to this */
private final ArrayOpHandler arrayOpHandler;
protected boolean isExceptionLabel(Object label) {
if (label == null) return false;
if (label instanceof Boolean) return false;
if (label instanceof Number) return false;
if (label == CAstControlFlowMap.SWITCH_DEFAULT) return false;
return true;
}
/**
* If this returns true, new global declarations get created for any attempt to access a
* non-existent variable (believe it or not, JavaScript actually does this!)
*/
protected boolean hasImplicitGlobals() {
return false;
}
/**
* If this returns true, then attempts to lookup non-existent names return `null' rather than
* tripping an assertion. This can be used when special handling is needed for built-in names.
* (PHP does this)
*/
protected boolean hasSpecialUndeclaredVariables() {
return false;
}
/**
* some languages let you omit initialization of certain fields when writing an object literal
* (e.g., PHP). This method should be overridden to handle such cases.
*/
protected void handleUnspecifiedLiteralKey() {
Assertions.UNREACHABLE();
}
/** generate prologue code for each function body */
protected void doPrologue(WalkContext context) {
// perform a lexical write to copy the value stored in the local
// associated with each parameter to the lexical name
final CAstEntity entity = context.top();
Set<String> exposedNames = entity2ExposedNames.get(entity);
if (exposedNames != null) {
int i = 0;
for (String arg : entity.getArgumentNames()) {
if (exposedNames.contains(arg)) {
final Scope currentScope = context.currentScope();
Symbol symbol = currentScope.lookup(arg);
assert symbol.getDefiningScope() == currentScope;
int argVN = symbol.valueNumber();
CAstType type =
(entity.getType() instanceof CAstType.Method)
? (CAstType) ((CAstType.Method) entity.getType()).getArgumentTypes().get(i)
: topType();
Access A = new Access(arg, context.getEntityName(entity), makeType(type), argVN);
context.cfg().addInstruction(new AstLexicalWrite(context.cfg().currentInstruction, A));
addExposedName(entity, entity, arg, argVN, true, context);
}
}
}
}
/** generate IR for call modeling creation of primitive value, updating context.cfg() */
protected abstract void doPrimitive(int resultVal, WalkContext context, CAstNode primitiveCall);
/**
* get the value number for a name defined locally (i.e., within the current method) by looking up
* the name in context.currentScope(). Note that the caller is responsible for ensuring that name
* is defined in the local scope.
*/
protected int doLocalRead(WalkContext context, String name, TypeReference type) {
CAstEntity entity = context.top();
Set<String> exposed = entity2ExposedNames.get(entity);
if (exposed != null && exposed.contains(name)) {
return doLexReadHelper(context, name, type);
}
return context.currentScope().lookup(name).valueNumber();
}
/**
* add an {@link AssignInstruction} to context.cfg() that copies rval to the value number of local
* nm. Note that the caller is responsible for ensuring that nm is defined in the local scope.
*/
protected void doLocalWrite(WalkContext context, String nm, TypeReference type, int rval) {
CAstEntity entity = context.top();
Set<String> exposed = entity2ExposedNames.get(entity);
if (exposed != null && exposed.contains(nm)) {
// use a lexical write
doLexicallyScopedWrite(context, nm, type, rval);
return;
}
int lval = context.currentScope().lookup(nm).valueNumber();
if (lval != rval) {
context
.cfg()
.addInstruction(new AssignInstruction(context.cfg().currentInstruction, lval, rval));
}
}
/**
* Note that the caller is responsible for ensuring that name is defined in a lexical scope.
*
* @param node the AST node representing the read
*/
protected int doLexicallyScopedRead(
CAstNode node, WalkContext context, final String name, TypeReference type) {
return doLexReadHelper(context, name, type);
}
/**
* @param name A variable name
* @return is this name safe to overwrite, i.e. it's synthetic from the translator?
*/
protected boolean ignoreName(String name) {
return false;
}
/**
* we only have this method to avoid having to pass a node parameter at other call sites, as would
* be required for {@link #doLexicallyScopedRead(CAstNode, WalkContext, String, TypeReference)}
*/
private static int doLexReadHelper(WalkContext context, final String name, TypeReference type) {
Symbol S = context.currentScope().lookup(name);
Scope definingScope = S.getDefiningScope();
CAstEntity E = definingScope.getEntity();
// record in declaring scope that the name is exposed to a nested scope
addExposedName(E, E, name, definingScope.lookup(name).valueNumber(), false, context);
final String entityName = context.getEntityName(E);
int result = context.currentScope().allocateTempValue();
Access A = new Access(name, entityName, type, result);
context.cfg().addInstruction(new AstLexicalRead(context.cfg().currentInstruction, A));
markExposedInEnclosingEntities(context, name, definingScope, type, E, entityName, false);
return result;
}
/**
* record name as exposed for the current entity and for all enclosing entities up to that of the
* defining scope, since if the name is updated via a call to a nested function, SSA for these
* entities may need to be updated with the new definition
*/
private static void markExposedInEnclosingEntities(
WalkContext context,
final String name,
Scope definingScope,
TypeReference type,
CAstEntity E,
final String entityName,
boolean isWrite) {
Scope curScope = context.currentScope();
while (!curScope.equals(definingScope)) {
final Symbol curSymbol = curScope.lookup(name);
final int vn = curSymbol.valueNumber();
final Access A = new Access(name, entityName, type, vn);
final CAstEntity entity = curScope.getEntity();
if (entity != definingScope.getEntity()) {
addExposedName(entity, E, name, vn, isWrite, context);
// record the access; later, the Accesses in the instruction
// defining vn will be adjusted based on this information; see
// patchLexicalAccesses()
addAccess(context, entity, A);
}
curScope = curScope.getParent();
}
}
/** Note that the caller is responsible for ensuring that name is defined in a lexical scope. */
protected void doLexicallyScopedWrite(
WalkContext context, String name, TypeReference type, int rval) {
Symbol S = context.currentScope().lookup(name);
Scope definingScope = S.getDefiningScope();
CAstEntity E = definingScope.getEntity();
// record in declaring scope that the name is exposed to a nested scope
addExposedName(E, E, name, definingScope.lookup(name).valueNumber(), true, context);
// lexically-scoped variables must be written in their scope each time
Access A = new Access(name, context.getEntityName(E), type, rval);
context.cfg().addInstruction(new AstLexicalWrite(context.cfg().currentInstruction, A));
markExposedInEnclosingEntities(
context, name, definingScope, type, E, context.getEntityName(E), true);
}
/** generate instructions for a read of a global */
protected int doGlobalRead(
@SuppressWarnings("unused") CAstNode node,
WalkContext context,
String name,
TypeReference type) {
// Global variables can be treated as lexicals defined in the CG root, or
if (treatGlobalsAsLexicallyScoped()) {
int result = context.currentScope().allocateTempValue();
Access A = new Access(name, null, type, result);
context.cfg().addInstruction(new AstLexicalRead(context.cfg().currentInstruction, A));
addAccess(context, context.top(), A);
return result;
// globals can be treated as a single static location
} else {
int result = context.currentScope().allocateTempValue();
FieldReference global = makeGlobalRef(name);
context
.cfg()
.addInstruction(new AstGlobalRead(context.cfg().currentInstruction, result, global));
return result;
}
}
/** generate instructions for a write of a global */
protected void doGlobalWrite(WalkContext context, String name, TypeReference type, int rval) {
// Global variables can be treated as lexicals defined in the CG root, or
if (treatGlobalsAsLexicallyScoped()) {
Access A = new Access(name, null, type, rval);
context.cfg().addInstruction(new AstLexicalWrite(context.cfg().currentInstruction, A));
addAccess(context, context.top(), A);
// globals can be treated as a single static location
} else {
FieldReference global = makeGlobalRef(name);
context
.cfg()
.addInstruction(new AstGlobalWrite(context.cfg().currentInstruction, global, rval));
}
}
/**
* creates a reference to a global named globalName. the declaring type and type of the global are
* both the root type.
*/
protected FieldReference makeGlobalRef(String globalName) {
TypeReference rootTypeRef =
TypeReference.findOrCreate(loader.getReference(), AstTypeReference.rootTypeName);
return FieldReference.findOrCreate(
rootTypeRef, Atom.findOrCreateUnicodeAtom("global " + globalName), rootTypeRef);
}
protected final IClassLoader loader;
/**
* for handling languages that let you include other source files named statically (e.g., ABAP)
*/
protected final Map<Object, CAstEntity> namedEntityResolver;
protected final SSAInstructionFactory insts;
protected AstTranslator(
IClassLoader loader,
Map<Object, CAstEntity> namedEntityResolver,
ArrayOpHandler arrayOpHandler) {
this.loader = loader;
this.namedEntityResolver = namedEntityResolver;
this.arrayOpHandler = arrayOpHandler != null ? arrayOpHandler : this;
this.insts = loader.getInstructionFactory();
}
protected AstTranslator(IClassLoader loader, Map<Object, CAstEntity> namedEntityResolver) {
this(loader, namedEntityResolver, null);
}
protected AstTranslator(IClassLoader loader) {
this(loader, null);
}
/** for keeping position information for the generated SSAInstructions and SSA locals */
private static class AstDebuggingInformation implements DebuggingInformation {
private final Position codeBodyPosition;
private final Position codeBodyNamePosition;
private final String[][] valueNumberNames;
private final Position[] instructionPositions;
private final Position[][] operandPositions;
private final Position[] parameterPositions;
private final SortedSet<Position> codePositions;
AstDebuggingInformation(
Position codeBodyNamePosition,
Position codeBodyPosition,
Position[] instructionPositions,
Position[][] operandPositions,
Position[] parameterPositions,
String[] names,
SortedSet<Position> codePositions) {
this.codePositions = codePositions;
this.codeBodyNamePosition = codeBodyNamePosition;
this.codeBodyPosition = codeBodyPosition;
this.instructionPositions = instructionPositions;
this.operandPositions = operandPositions;
this.parameterPositions = parameterPositions;
valueNumberNames = new String[names.length][];
for (int i = 0; i < names.length; i++) {
if (names[i] != null) {
valueNumberNames[i] = new String[] {names[i]};
} else {
valueNumberNames[i] = new String[0];
}
}
}
@Override
public Position getCodeBodyPosition() {
return codeBodyPosition;
}
@Override
public Position getCodeNamePosition() {
return codeBodyNamePosition;
}
@Override
public Position getInstructionPosition(int instructionOffset) {
return instructionPositions[instructionOffset];
}
@Override
public Position getOperandPosition(int instructionOffset, int operand) {
if (operandPositions[instructionOffset] != null
&& operandPositions[instructionOffset].length > operand) {
return operandPositions[instructionOffset][operand];
} else {
return null;
}
}
@Override
public String[][] getSourceNamesForValues() {
return valueNumberNames;
}
@Override
public Position getParameterPosition(int param) {
return parameterPositions[param];
}
private static boolean disjoint(Position a, Position b) {
return (a.getLastLine() < b.getFirstLine()
|| (a.getLastLine() == b.getFirstLine() && a.getLastCol() < b.getFirstCol()))
|| (b.getLastLine() < a.getFirstLine()
|| (b.getLastLine() == a.getFirstLine() && b.getLastCol() < a.getFirstCol()));
}
private String getComment(int instructionOffset, Function<Position, SortedSet<Position>> set)
throws IOException {
Position pos = getInstructionPosition(instructionOffset);
if (pos == null) {
return null;
} else {
SortedSet<Position> prevSet = set.apply(pos);
if (prevSet != null && !prevSet.isEmpty()) {
Position ppos = null;
for (Position other : prevSet) {
if (disjoint(other, pos)) {
ppos = other;
break;
}
}
if (ppos == null) {
return null;
}
Position first, second;
if (ppos.compareTo(pos) < 0) {
first = ppos;
second = pos;
} else {
first = pos;
second = ppos;
}
Position intermediate =
new AbstractSourcePosition() {
@Override
public URL getURL() {
return pos.getURL();
}
@Override
public Reader getReader() throws IOException {
return pos.getReader();
}
@Override
public int getFirstLine() {
return first.getLastLine();
}
@Override
public int getLastLine() {
return second.getFirstLine();
}
@Override
public int getFirstCol() {
return first.getLastCol();
}
@Override
public int getLastCol() {
return second.getFirstCol();
}
@Override
public int getFirstOffset() {
return first.getLastOffset();
}
@Override
public int getLastOffset() {
return second.getFirstOffset();
}
};
return new SourceBuffer(intermediate).toString();
}
}
return null;
}
@Override
public String getFollowingComment(int instructionOffset) throws IOException {
return getComment(instructionOffset, codePositions::tailSet);
}
@Override
public String getLeadingComment(int instructionOffset) throws IOException {
return getComment(instructionOffset, codePositions::headSet);
}
}
public static final boolean DEBUG_ALL = false;
public static final boolean DEBUG_TOP = DEBUG_ALL || false;
public static final boolean DEBUG_CFG = DEBUG_ALL || false;
public static final boolean DEBUG_NAMES = DEBUG_ALL || false;
public static final boolean DEBUG_LEXICAL = DEBUG_ALL || false;
/**
* basic block implementation used in the CFGs constructed during the IR-generating AST traversal
*/
protected static final class PreBasicBlock implements IBasicBlock<SSAInstruction> {
private static final int NORMAL = 0;
private static final int HANDLER = 1;
private static final int ENTRY = 2;
private static final int EXIT = 3;
private int kind = NORMAL;
private int number = -1;
private int firstIndex = -1;
private int lastIndex = -2;
private final List<SSAInstruction> instructions = new ArrayList<>();
@Override
public int getNumber() {
return getGraphNodeId();
}
@Override
public int getGraphNodeId() {
return number;
}
@Override
public void setGraphNodeId(int number) {
this.number = number;
}
@Override
public int getFirstInstructionIndex() {
return firstIndex;
}
void setFirstIndex(int firstIndex) {
this.firstIndex = firstIndex;
}
@Override
public int getLastInstructionIndex() {
return lastIndex;
}
void setLastIndex(int lastIndex) {
this.lastIndex = lastIndex;
}
void makeExitBlock() {
kind = EXIT;
}
void makeEntryBlock() {
kind = ENTRY;
}
void makeHandlerBlock() {
kind = HANDLER;
}
@Override
public boolean isEntryBlock() {
return kind == ENTRY;
}
@Override
public boolean isExitBlock() {
return kind == EXIT;
}
public boolean isHandlerBlock() {
return kind == HANDLER;
}
@Override
public String toString() {
return "PreBB" + number + ':' + firstIndex + ".." + lastIndex;
}
private List<SSAInstruction> instructions() {
return instructions;
}
@Override
public boolean isCatchBlock() {
return (lastIndex > -1) && (instructions.get(0) instanceof SSAGetCaughtExceptionInstruction);
}
@Override
public IMethod getMethod() {
return null;
}
@Override
public Iterator<SSAInstruction> iterator() {
return instructions.iterator();
}
}
protected static final class UnwindState {
final CAstNode unwindAst;
final WalkContext astContext;
final CAstVisitor<WalkContext> astVisitor;
UnwindState(CAstNode unwindAst, WalkContext astContext, CAstVisitor<WalkContext> astVisitor) {
this.unwindAst = unwindAst;
this.astContext = astContext;
this.astVisitor = astVisitor;
}
public UnwindState getParent() {
return astContext.getUnwindState();
}
@Override
public int hashCode() {
return astContext.hashCode() * unwindAst.hashCode() * astVisitor.hashCode();
}
@Override
public boolean equals(Object o) {
if (o instanceof UnwindState) {
if (((UnwindState) o).unwindAst != unwindAst) return false;
if (((UnwindState) o).astVisitor != astVisitor) return false;
if (getParent() == null) {
return ((UnwindState) o).getParent() == null;
} else {
return getParent().equals(((UnwindState) o).getParent());
}
}
return false;
}
boolean covers(UnwindState other) {
if (equals(other)) return true;
if (getParent() != null) return getParent().covers(other);
return false;
}
}
/**
* holds the control-flow graph as it is being constructed. When construction is complete,
* information is stored in an {@link AstCFG}
*/
public final class IncipientCFG extends SparseNumberedGraph<PreBasicBlock> {
protected class Unwind {
private final Map<PreBasicBlock, UnwindState> unwindData = new LinkedHashMap<>();
/** a cache of generated blocks */
private final Map<Pair<UnwindState, Pair<PreBasicBlock, Boolean>>, PreBasicBlock> code =
new LinkedHashMap<>();
void setUnwindState(PreBasicBlock block, UnwindState context) {
unwindData.put(block, context);
}
void setUnwindState(CAstNode node, UnwindState context) {
unwindData.put(nodeToBlock.get(node), context);
}
/**
* When adding an edge from source to target, it is possible that certain exception-handling
* code needs to be executed before the control is actually transfered to target. This method
* determines if this is the case, and if so, it generates the exception handler blocks and
* adds an appropriate edge to the target. It returns the basic block that should be the
* target of the edge from source (target itself if there is no exception-handling code, the
* initial catch block otherwise)
*/
public PreBasicBlock findOrCreateCode(
PreBasicBlock source, PreBasicBlock target, final boolean exception) {
final UnwindState sourceContext = unwindData.get(source);
// no unwinding is needed, so jump to target block directly
if (sourceContext == null) return target;
final WalkContext sourceAstContext = sourceContext.astContext;
final UnwindState targetContext = target == null ? null : unwindData.get(target);
// in unwind context, but catch in same (or inner) unwind context
if (targetContext != null && targetContext.covers(sourceContext)) return target;
Pair<UnwindState, Pair<PreBasicBlock, Boolean>> key =
Pair.make(sourceContext, Pair.make(target, exception));
if (code.containsKey(key)) {
return code.get(key);
} else {
// generate a copy of the finally block
int exceptionVarValNum = -1;
final CAstNode dummyExceptionTarget =
exception ? (new CAstImpl()).makeNode(CAstNode.EMPTY) : null;
PreBasicBlock blockBeforeFinallyCopy = getCurrentBlock();
if (!isDeadBlock(blockBeforeFinallyCopy)) {
addInstruction(insts.GotoInstruction(currentInstruction, -1));
newBlock(false);
}
PreBasicBlock startBlock = getCurrentBlock();
if (exception) {
setCurrentBlockAsHandler();
exceptionVarValNum = sourceAstContext.currentScope().allocateTempValue();
addInstruction(
insts.GetCaughtExceptionInstruction(
currentInstruction, startBlock.getNumber(), exceptionVarValNum));
sourceAstContext.setCatchType(startBlock, defaultCatchType());
}
UnwindState curUnwindState = sourceContext;
while (curUnwindState != null
&& (targetContext == null || !targetContext.covers(curUnwindState))) {
WalkContext curUnwindAstContext = curUnwindState.astContext;
final CAstRewriter.Rewrite ast =
(new CAstCloner(new CAstImpl()) {
@Override
protected CAstNode flowOutTo(
Map<Pair<CAstNode, NoKey>, CAstNode> nodeMap,
CAstNode oldSource,
Object label,
CAstNode oldTarget,
CAstControlFlowMap orig,
CAstSourcePositionMap src) {
if (exception && !isExceptionLabel(label)) {
return dummyExceptionTarget;
} else {
return oldTarget;
}
}
})
.copy(
curUnwindState.unwindAst,
curUnwindAstContext.getControlFlow(),
curUnwindAstContext.getSourceMap(),
curUnwindAstContext.top().getNodeTypeMap(),
curUnwindAstContext.top().getAllScopedEntities(),
curUnwindAstContext.top().getArgumentDefaults());
curUnwindState.astVisitor.visit(
ast.newRoot(),
new DelegatingContext(curUnwindAstContext) {
@Override
public CAstSourcePositionMap getSourceMap() {
return ast.newPos();
}
@Override
public CAstControlFlowMap getControlFlow() {
return ast.newCfg();
}
},
curUnwindState.astVisitor);
curUnwindState = curUnwindState.getParent();
}
PreBasicBlock endBlock = getCurrentBlock();
if (exception) {
// rethrow the exception
assert unwindData.get(endBlock) == null;
addPreNode(dummyExceptionTarget);
doThrow(sourceAstContext, exceptionVarValNum);
} else {
addInstruction(insts.GotoInstruction(currentInstruction, -1));
}
newBlock(false);
if (target != null) {
addEdge(blockBeforeFinallyCopy, getCurrentBlock());
assert unwindData.get(getCurrentBlock()) == null;
addEdge(endBlock, target);
// assert unwindData.get(target) == null;
// `null' target is idiom for branch/throw to exit
} else {
if (exception) {
addEdge(blockBeforeFinallyCopy, getCurrentBlock());
} else {
addDelayedEdge(endBlock, exitMarker, exception);
}
}
code.put(key, startBlock);
return startBlock;
}
}
}
private Unwind unwind = null;
private final List<PreBasicBlock> blocks = new ArrayList<>();
private PreBasicBlock entryBlock;
private final Map<CAstNode, PreBasicBlock> nodeToBlock = new LinkedHashMap<>();
private final Map<Object, Set<Pair<PreBasicBlock, Boolean>>> delayedEdges =
new LinkedHashMap<>();
private final Object exitMarker = new Object();
private final Set<PreBasicBlock> deadBlocks = new LinkedHashSet<>();
private final Set<PreBasicBlock> normalToExit = new LinkedHashSet<>();
private final Set<PreBasicBlock> exceptionalToExit = new LinkedHashSet<>();
private Position[] linePositions = new Position[10];
private Position[][] operandPositions = new Position[10][];
private boolean hasCatchBlock = false;
/** does the method have any monitor operations? */
private boolean hasMonitorOp = false;
private int currentInstruction = 0;
private PreBasicBlock currentBlock;
public int getCurrentInstruction() {
return currentInstruction;
}
public PreBasicBlock getCurrentBlock() {
return currentBlock;
}
boolean hasCatchBlock() {
return hasCatchBlock;