Merge pull request #146 from mkouba/string-switch-optimize-hash-colli…

…sion StringSwitch - fix hashCode collisons
quarkusio · Jan 4, 2023 · ab1c927 · ab1c927
2 parents 1185f56 + f51bebd
commit ab1c927
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Showing 2 changed files with 8 additions and 4 deletions.
diff --git a/src/main/java/io/quarkus/gizmo/EnumSwitchImpl.java b/src/main/java/io/quarkus/gizmo/EnumSwitchImpl.java
@@ -74,7 +74,7 @@ void writeBytecode(MethodVisitor methodVisitor) {
                     if (caseBlock != null && !fallThrough) {
                         caseBlock.breakScope(EnumSwitchImpl.this);
                     } else if (caseBlock == null) {
-                        // Add empty fall through block
+                        // Add an empty fall through block
                         caseBlock = new BytecodeCreatorImpl(EnumSwitchImpl.this);
                         caseEntry.setValue(caseBlock);
                     }

diff --git a/src/main/java/io/quarkus/gizmo/StringSwitchImpl.java b/src/main/java/io/quarkus/gizmo/StringSwitchImpl.java
@@ -49,19 +49,23 @@ void writeBytecode(MethodVisitor methodVisitor) {
                 // Initialize the case blocks and lookup blocks
                 for (Entry<Integer, List<Entry<String, BytecodeCreatorImpl>>> hashEntry : hashToCaseBlocks.entrySet()) {
                     BytecodeCreatorImpl lookupBlock = new BytecodeCreatorImpl(StringSwitchImpl.this);
-                    for (Entry<String, BytecodeCreatorImpl> caseEntry : hashEntry.getValue()) {
+                    for (Iterator<Entry<String, BytecodeCreatorImpl>> it = hashEntry.getValue().iterator(); it.hasNext();) {
+                        Entry<String, BytecodeCreatorImpl> caseEntry = it.next();
                         BytecodeCreatorImpl caseBlock = caseEntry.getValue();
                         if (caseBlock != null && !fallThrough) {
                             caseBlock.breakScope(StringSwitchImpl.this);
                         } else if (caseBlock == null) {
-                            // TODO empty block
+                            // Add an empty fall through block
                             caseBlock = new BytecodeCreatorImpl(StringSwitchImpl.this);
                             caseEntry.setValue(caseBlock);
                         }
-                        // caseBlock.findActiveResultHandles(inputHandles);
                         BytecodeCreatorImpl isEqual = (BytecodeCreatorImpl) lookupBlock
                                 .ifTrue(Gizmo.equals(lookupBlock, lookupBlock.load(caseEntry.getKey()), value)).trueBranch();
                         isEqual.jumpTo(caseBlock);
+                        if (!it.hasNext()) {
+                            // None of the labels is equal to the tested value - skip to the default block
+                            lookupBlock.jumpTo(defaultBlock);
+                        }
                     }
                     hashToLabel.put(hashEntry.getKey(), lookupBlock.getTop());
                     lookupBlock.findActiveResultHandles(inputHandles);