[IR] Reduce unnecessary allocations

compiler/backend.common.jvm/src/org/jetbrains/kotlin/codegen/signature/JvmSignatureWriter.java

@@ -138,11 +138,11 @@ public class JvmSignatureWriter extends JvmDescriptorTypeWriter<Type> {
 
     @NotNull
     public JvmMethodGenericSignature makeJvmMethodSignature(@NotNull String name) {
-        List<Type> types = new ArrayList<>(kotlinParameterTypes.size());
-        for (JvmMethodParameterSignature parameter : kotlinParameterTypes) {
-            types.add(parameter.getAsmType());
+        Type[] types = new Type[kotlinParameterTypes.size()];
+        for (int i = 0; i < kotlinParameterTypes.size(); i++) {
+            types[i] = kotlinParameterTypes.get(i).getAsmType();
         }
-        Method asmMethod = new Method(name, jvmReturnType, types.toArray(new Type[types.size()]));
+        Method asmMethod = new Method(name, jvmReturnType, types);
         return new JvmMethodGenericSignature(asmMethod, kotlinParameterTypes, makeJavaGenericSignature());
     }
 

compiler/ir/backend.jvm/lower/src/org/jetbrains/kotlin/backend/jvm/lower/UniqueLoopLabelsLowering.kt

@@ -12,29 +12,40 @@ import org.jetbrains.kotlin.ir.IrElement
 import org.jetbrains.kotlin.ir.declarations.IrDeclarationWithName
 import org.jetbrains.kotlin.ir.declarations.IrFile
 import org.jetbrains.kotlin.ir.expressions.IrLoop
-import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
+import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
+import org.jetbrains.kotlin.ir.visitors.acceptChildrenVoid
+import org.jetbrains.kotlin.ir.visitors.acceptVoid
+import org.jetbrains.kotlin.name.Name
 
 internal val uniqueLoopLabelsPhase = makeIrFilePhase(
-    ::UniqueLoopLabelsLowering,
+    { _: JvmBackendContext -> UniqueLoopLabelsLowering() },
     name = "UniqueLoopLabels",
     description = "Label all loops for non-local break/continue"
 )
 
-private class UniqueLoopLabelsLowering(val context: JvmBackendContext) : FileLoweringPass {
+private class UniqueLoopLabelsLowering : FileLoweringPass {
     override fun lower(irFile: IrFile) {
-        irFile.accept(object : IrElementVisitor<Unit, String> {
+        irFile.acceptVoid(object : IrElementVisitorVoid {
             // This counter is intentionally not local to every declaration because their names might clash.
             private var counter = 0
+            private val stack = ArrayList<Name>()
 
-            override fun visitElement(element: IrElement, data: String) =
-                element.acceptChildren(this, if (element is IrDeclarationWithName) "$data${element.name}$" else data)
+            override fun visitElement(element: IrElement) {
+                if (element is IrDeclarationWithName) {
+                    stack.add(element.name)
+                    element.acceptChildrenVoid(this)
+                    stack.removeLast()
+                } else {
+                    element.acceptChildrenVoid(this)
+                }
+            }
 
-            override fun visitLoop(loop: IrLoop, data: String) {
+            override fun visitLoop(loop: IrLoop) {
                 // Give all loops unique labels so that we can generate unambiguous instructions for non-local
                 // `break`/`continue` statements.
-                loop.label = "$data${++counter}"
-                super.visitLoop(loop, data)
+                loop.label = stack.joinToString("$", postfix = (++counter).toString())
+                super.visitLoop(loop)
             }
-        }, "")
+        })
     }
 }

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/caches/BridgeLoweringCache.kt

@@ -35,9 +35,12 @@ class BridgeLoweringCache(private val context: JvmBackendContext) {
             return true
         // Function name could be mangled by inline class rules
         val functionName = function.name.asString()
-        if (specialBridgeMethods.specialMethodNames.any { functionName.startsWith(it.asString() + "-") })
-            return true
-        return false
+        return specialBridgeMethods.specialMethodNames.any {
+            // Optimized version of functionName.startsWith(it.asString() + "-") which is a hot spot
+            val specialMethodNameString = it.asString()
+            val specialMethodNameLength = specialMethodNameString.length
+            functionName.startsWith(specialMethodNameString) && functionName.length > specialMethodNameLength && functionName[specialMethodNameLength] == '-'
+        }
     }
 
     fun computeSpecialBridge(function: IrSimpleFunction): SpecialBridge? {

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/types/irTypePredicates.kt

@@ -14,6 +14,7 @@ import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.symbols.IrClassifierSymbol
 import org.jetbrains.kotlin.ir.util.IdSignature
 import org.jetbrains.kotlin.ir.util.hasEqualFqName
+import org.jetbrains.kotlin.ir.util.hasTopLevelEqualFqName
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.FqNameUnsafe
 import org.jetbrains.kotlin.name.Name
@@ -74,8 +75,7 @@ private fun IrType.isClassType(signature: IdSignature.CommonSignature, nullable:
 }
 
 private fun IrClass.hasFqNameEqualToSignature(signature: IdSignature.CommonSignature): Boolean =
-    name.asString() == signature.shortName &&
-            hasEqualFqName(FqName("${signature.packageFqName}.${signature.declarationFqName}"))
+    name.asString() == signature.shortName && hasTopLevelEqualFqName(signature.packageFqName, signature.declarationFqName)
 
 fun IrClassifierSymbol.isClassWithFqName(fqName: FqNameUnsafe): Boolean =
     this is IrClassSymbol && classFqNameEquals(this, fqName)

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/AdditionalIrUtils.kt

@@ -146,9 +146,27 @@ fun IrDeclarationWithName.hasEqualFqName(fqName: FqName): Boolean =
         else -> false
     }
 
+fun IrDeclarationWithName.hasTopLevelEqualFqName(packageName: String, declarationName: String): Boolean =
+    symbol.hasTopLevelEqualFqName(packageName, declarationName) || name.asString() == declarationName && when (val parent = parent) {
+        is IrPackageFragment -> parent.packageFqName.asString() == packageName
+        else -> false
+    }
+
 fun IrSymbol.hasEqualFqName(fqName: FqName): Boolean {
     return this is IrClassPublicSymbolImpl && with(signature as? IdSignature.CommonSignature ?: return false) {
-        FqName("$packageFqName.$declarationFqName") == fqName
+        // optimized version of FqName("$packageFqName.$declarationFqName") == fqName
+        val fqNameAsString = fqName.asString()
+        fqNameAsString.length == packageFqName.length + 1 + declarationFqName.length &&
+                fqNameAsString[packageFqName.length] == '.' &&
+                fqNameAsString.startsWith(packageFqName) &&
+                fqNameAsString.endsWith(declarationFqName)
+    }
+}
+
+private fun IrSymbol.hasTopLevelEqualFqName(packageName: String, declarationName: String): Boolean {
+    return this is IrClassPublicSymbolImpl && with(signature as? IdSignature.CommonSignature ?: return false) {
+        // optimized version of FqName("$packageFqName.$declarationFqName") == fqName
+        packageFqName == packageName && declarationFqName == declarationName
     }
 }