OpenJDK / amber / amber
changeset 57025:a898dc684456 patterns
Improving fallthrough handling in switches with patterns.
| author | jlahoda |
|---|---|
| date | Wed, 21 Aug 2019 13:28:16 +0200 |
| parents | c91c71a053ad |
| children | 00dece45a5de e80040658b50 |
| files | src/jdk.compiler/share/classes/com/sun/tools/javac/comp/TransPatterns.java |
| diffstat | 1 files changed, 14 insertions(+), 5 deletions(-) [+] |
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--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/TransPatterns.java Tue Aug 20 15:59:21 2019 +0200 +++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/TransPatterns.java Wed Aug 21 13:28:16 2019 +0200 @@ -294,9 +294,10 @@ pendingMatchLabel = make.Labelled(names.fromString("match$" + tree.pos), null); VarSymbol fallthroughSym = new VarSymbol(0, names.fromString("fallthrough$" + tree.pos), syms.booleanType, currentMethodSym); - JCStatement fallthroughInit = make.at(tree.pos).VarDef(fallthroughSym, make.Literal(BOOLEAN, 0).setType(syms.booleanType)); + boolean hasFallThrough = false; + boolean wasFallThrough = false; - List<JCStatement> resultStatements = List.of(fallthroughInit); + List<JCStatement> resultStatements = List.nil(); for (JCCase clause : tree.cases) { Assert.check(clause.pats.size() <= 1); @@ -311,12 +312,20 @@ JCStatement translatedIf = translate(make.If(jcMatches, body, null)); JCIf testStatement = translatedIf.hasTag(Tag.IF) ? (JCIf)translatedIf : (JCIf) ((JCBlock)translatedIf).stats.tail.head; - testStatement.cond = makeBinary(Tag.OR, - make.Ident(fallthroughSym), - testStatement.cond); + if (wasFallThrough) { + testStatement.cond = makeBinary(Tag.OR, + make.Ident(fallthroughSym), + testStatement.cond); + } + hasFallThrough |= wasFallThrough = clause.completesNormally; resultStatements = resultStatements.append(translatedIf); } + if (hasFallThrough) { + resultStatements = resultStatements.prepend(make.at(tree.pos) + .VarDef(fallthroughSym, + make.Literal(BOOLEAN, 0).setType(syms.booleanType))); + } pendingMatchLabel.body = make.Block(0, resultStatements); result = pendingMatchLabel; } finally {