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Fix grammar

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The BlockStatement production is rewritten for performance
and clarity. There was a problem with ModifierLists floating around
This commit is contained in:
Clément Fournier
2020-08-23 15:38:21 +02:00
parent 9eb6602b7c
commit f3d887956d
3 changed files with 105 additions and 53 deletions
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142
pmd-java/etc/grammar/Java.jjt
View File

@ -275,6 +275,10 @@ class JavaParserImpl {
return (jdkVersion == 14 || jdkVersion == 15) && preview;
}
private boolean localTypesSupported() {
return isRecordTypeSupported();
}
private boolean isSealedClassSupported() {
return jdkVersion == 15 && preview;
}
@ -294,7 +298,7 @@ class JavaParserImpl {
// This is a semantic LOOKAHEAD to determine if we're dealing with an assert
// Note that this can't be replaced with a syntactic lookahead
// since "assert" isn't a string literal token
private boolean isNextTokenAnAssert() {
private boolean isAssertStart() {
if (jdkVersion <= 3) {
return false;
}
@ -302,6 +306,14 @@ class JavaParserImpl {
return getToken(1).getImage().equals("assert");
}
private boolean isRecordStart() {
return isRecordTypeSupported() && isKeyword("record");
}
private boolean isEnumStart() {
return jdkVersion >= 5 && isKeyword("enum");
}
/**
* Semantic lookahead to check if the next identifier is a
* specific restricted keyword.
@ -357,13 +369,22 @@ class JavaParserImpl {
|| isSealedClassSupported() && isNonSealedModifier();
}
private boolean localTypeDeclLookahead() {
private boolean localTypeDeclAfterModifiers() {
Token next = getToken(1);
return next.kind == CLASS
|| isRecordTypeSupported() && next.kind == INTERFACE
|| isRecordTypeSupported() && next.kind == AT && isToken(2, INTERFACE)
|| isRecordTypeSupported() && next.kind == IDENTIFIER && next.getImage().equals("enum")
|| isRecordTypeSupported() && next.kind == IDENTIFIER && next.image.equals("record");
|| localTypesSupported() && (
next.kind == INTERFACE
|| next.kind == AT && isToken(2, INTERFACE)
|| next.kind == IDENTIFIER && next.getImage().equals("enum")
||
next.kind == IDENTIFIER && next.image.equals("record")
);
}
private boolean localTypeDeclGivenNextIsIdent() {
return localTypesSupported() && (
isNonSealedModifier() || isRecordStart() || isEnumStart()
);
}
/**
@ -436,6 +457,11 @@ class JavaParserImpl {
node.setImage(getToken(0).getImage());
}
private void fixLastToken() {
AbstractJavaNode top = (AbstractJavaNode) jjtree.peekNode();
top.setLastToken(getToken(0));
}
private void forceExprContext() {
AbstractJavaNode top = jjtree.peekNode();
@ -2127,8 +2153,20 @@ void ArrayDimExpr() #void:
void Statement() #void:
{}
{
Block()
StatementNoIdent()
// testing the hard cases last optimises the code gen
// all the previous cases are trivial for the parser
// because they start with a different token
| LOOKAHEAD( { isYieldStart() } ) YieldStatement()
| LOOKAHEAD( { isAssertStart() } ) AssertStatement()
| LOOKAHEAD(2) LabeledStatement()
| ( StatementExpression() ";" ) #ExpressionStatement
}
void StatementNoIdent() #void:
{}
{
Block()
| EmptyStatement()
| SwitchStatement()
| IfStatement()
@ -2141,12 +2179,6 @@ void Statement() #void:
| ThrowStatement()
| SynchronizedStatement()
| TryStatement()
// testing the hard cases last optimises the code gen
// all the previous cases are trivial for the parser
// because they start with a different token
| LOOKAHEAD( { isNextTokenAnAssert() } ) AssertStatement()
| LOOKAHEAD(2) LabeledStatement()
| ( StatementExpression() ";" ) #ExpressionStatement
}
void LabeledStatement() :
@ -2162,45 +2194,60 @@ void Block() :
}
void BlockStatement() #void:
{}
{} // Note: this has been written this way to minimize lookaheads
// This generates a table switch with very few lookaheads
{
LOOKAHEAD( { isNextTokenAnAssert() } ) AssertStatement()
| LOOKAHEAD( { isYieldStart() } ) YieldStatement()
| LOOKAHEAD( "@" | "final" )
LOOKAHEAD(1, "@" | "final" )
// this eagerly parses all modifiers and annotations. After that, either a local type declaration
// or a local variable declaration follows.
// This allows more modifiers for local variables than actually allowed
// and the annotations for local variables need to be moved in the AST down again.
ModifierList()
(
LOOKAHEAD({localTypeDeclLookahead()}) LocalTypeDecl()
|
LocalVariableDeclaration() ";"
// The ModifierList is adopted by the next class to open
ModifierList() (
LOOKAHEAD({localTypeDeclAfterModifiers()}) LocalTypeDecl()
| LOOKAHEAD({true}) LocalVariableDeclaration() ";" { fixLastToken(); }
)
| LOOKAHEAD({classModifierLookahead() || localTypeDeclLookahead()})
ModifierList() LocalTypeDecl()
| LOOKAHEAD(Type() <IDENTIFIER>)
LocalVariableDeclaration() ";" {
// make it so that the LocalVariableDeclaration's last token is the semicolon
AbstractJavaNode top = (AbstractJavaNode) jjtree.peekNode();
top.setLastToken(getToken(0));
} {}
|
// we need to lookahead until the "class" token,
// because a method ref may be annotated
// -> so Expression, and hence Statement, may start with "@"
LOOKAHEAD(ModifierList() "class") LocalTypeDecl()
|
Statement()
| LOOKAHEAD(1, <IDENTIFIER>)
(
LOOKAHEAD({ localTypeDeclGivenNextIsIdent() }) ModifierList() LocalTypeDecl()
| LOOKAHEAD({ isAssertStart() }) AssertStatement()
| LOOKAHEAD({ isYieldStart() }) YieldStatement()
| LOOKAHEAD({ getToken(2).kind == COLON }) LabeledStatement()
| LOOKAHEAD(ClassOrInterfaceType() <IDENTIFIER>) LocalVariableDeclaration() ";" { fixLastToken(); }
| LOOKAHEAD({true}) ExpressionStatement()
)
| LOOKAHEAD(1, LocalTypeStartNoIdent()) ModifierList() LocalTypeDecl()
| LOOKAHEAD(1) StatementNoIdent()
| LOOKAHEAD(Type() <IDENTIFIER>) LocalVariableDeclaration() ";" { fixLastToken(); }
| LOOKAHEAD({true}) ExpressionStatement()
}
void LocalTypeDecl() #LocalClassStatement:
private void LocalTypeStartNoIdent() #void: // A lookahead
{}
{
ClassOrInterfaceDeclaration()
{ // notice: not default
"public" | "static" | "protected" | "private" | "final"
| "abstract" | "synchronized" | "native" | "transient"
| "volatile" | "strictfp"
| "class" | "interface"
}
void LocalTypeDecl() #void:
{} // At the point this is called, a ModifierList is on the top of the stack,
{ // waiting for the next node to open. We want that node to be the type declaration,
// not the wrapper statement node.
( ClassOrInterfaceDeclaration()
| AnnotationTypeDeclaration()
| LOOKAHEAD({isKeyword("record")}) RecordDeclaration()
| LOOKAHEAD({isKeyword("enum")}) EnumDeclaration()
) {
// Wrap the type decl into a statement
// This can't be done with regular jjtree constructs, as the ModifierList
// is adopted by the first node to be opened.
ASTAnyTypeDeclaration type = (ASTAnyTypeDeclaration) jjtree.popNode();
ASTLocalClassStatement stmt = new ASTLocalClassStatement(type);
jjtree.pushNode(stmt);
}
}
/*
@ -2241,6 +2288,12 @@ void EmptyDeclaration() :
";"
}
void ExpressionStatement():
{}
{
StatementExpression() ";"
}
void StatementExpression() #void:
{AssignmentOp op = null;}
{
@ -2268,12 +2321,6 @@ void SwitchBlock() #void:
"}"
}
void SwitchArrowLahead() #void:
{}
{
SwitchLabel() "->"
}
void SwitchArrowBranch():
{}
{
@ -2671,3 +2718,4 @@ void VariableAccess(): {} { <IDENTIFIER> }
// those are created manually
void TypeExpression(): {} { <IDENTIFIER> }
void PatternExpression(): {} { <IDENTIFIER> }
void LocalClassStatement(): {} { TypeDeclaration() }

13
pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/ASTLocalClassStatement.java
View File

@ -12,7 +12,7 @@ import org.checkerframework.checker.nullness.qual.NonNull;
*
* <pre class="grammar">
*
* LocalClassStatement ::= {@link ASTClassOrInterfaceDeclaration ClassDeclaration}
* LocalClassStatement ::= {@link ASTAnyTypeDeclaration TypeDeclaration}
*
* </pre>
*/
@ -22,6 +22,12 @@ public final class ASTLocalClassStatement extends AbstractStatement {
super(id);
}
ASTLocalClassStatement(ASTAnyTypeDeclaration tdecl) {
super(JavaParserImplTreeConstants.JJTLOCALCLASSSTATEMENT);
assert tdecl != null;
addChild((AbstractJavaNode) tdecl, 0);
}
@Override
protected <P, R> R acceptVisitor(JavaVisitor<? super P, ? extends R> visitor, P data) {
return visitor.visit(this, data);
@ -31,8 +37,7 @@ public final class ASTLocalClassStatement extends AbstractStatement {
/**
* Returns the contained declaration.
*/
@NonNull
public ASTClassOrInterfaceDeclaration getDeclaration() {
return (ASTClassOrInterfaceDeclaration) getChild(0);
public @NonNull ASTAnyTypeDeclaration getDeclaration() {
return (ASTAnyTypeDeclaration) getChild(0);
}
}

3
pmd-java/src/main/java/net/sourceforge/pmd/lang/java/symbols/table/internal/SymbolTableResolver.java
View File

@ -17,7 +17,6 @@ import net.sourceforge.pmd.lang.java.ast.ASTAnonymousClassDeclaration;
import net.sourceforge.pmd.lang.java.ast.ASTAnyTypeDeclaration;
import net.sourceforge.pmd.lang.java.ast.ASTBlock;
import net.sourceforge.pmd.lang.java.ast.ASTCatchClause;
import net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceDeclaration;
import net.sourceforge.pmd.lang.java.ast.ASTCompilationUnit;
import net.sourceforge.pmd.lang.java.ast.ASTConstructorCall;
import net.sourceforge.pmd.lang.java.ast.ASTFieldDeclaration;
@ -282,7 +281,7 @@ public final class SymbolTableResolver {
if (st instanceof ASTLocalVariableDeclaration) {
pushed += pushOnStack(f.localVarSymTable(top(), ((ASTLocalVariableDeclaration) st).getVarIds()));
} else if (st instanceof ASTLocalClassStatement) {
ASTClassOrInterfaceDeclaration local = ((ASTLocalClassStatement) st).getDeclaration();
ASTAnyTypeDeclaration local = ((ASTLocalClassStatement) st).getDeclaration();
pushed += pushOnStack(f.localTypeSymTable(top(), local.getSymbol()));
processTypeHeader(local);
}