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[FIR2IR] Extract generateWhen & toIrWhenBranch

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This commit is contained in:
Mikhail Glukhikh
2020-07-01 11:26:57 +03:00
committed by Dmitriy Novozhilov
parent 31765a4abc
commit 6229d2e215
1 changed files with 49 additions and 39 deletions
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compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt
+49 -39
View File
@@ -638,49 +638,59 @@ class Fir2IrVisitor(
KtNodeTypes.POSTFIX_EXPRESSION -> IrStatementOrigin.EXCLEXCL
else -> null
}
// If the constant true branch has empty body, it won't be converted. Thus, the entire `when` expression is effectively _not_
// exhaustive anymore. In that case, coerce the return type of `when` expression to Unit as per the backend expectation.
val effectivelyNotExhaustive = !whenExpression.isExhaustive ||
whenExpression.branches.any { it.condition is FirElseIfTrueCondition && it.result.statements.isEmpty() }
return conversionScope.withWhenSubject(subjectVariable) {
whenExpression.convertWithOffsets { startOffset, endOffset ->
val irWhen = IrWhenImpl(
startOffset, endOffset,
if (effectivelyNotExhaustive) irBuiltIns.unitType else whenExpression.typeRef.toIrType(),
origin
).apply {
var unconditionalBranchFound = false
for (branch in whenExpression.branches) {
if (branch.condition !is FirElseIfTrueCondition) {
branches += branch.accept(this@Fir2IrVisitor, data) as IrBranch
} else {
unconditionalBranchFound = true
if (branch.result.statements.isNotEmpty()) {
branches += branch.accept(this@Fir2IrVisitor, data) as IrBranch
}
}
}
if (whenExpression.isExhaustive && !unconditionalBranchFound) {
val irResult = IrCallImpl(
startOffset, endOffset, irBuiltIns.nothingType,
irBuiltIns.noWhenBranchMatchedExceptionSymbol,
typeArgumentsCount = 0,
valueArgumentsCount = 0
)
branches += IrElseBranchImpl(
IrConstImpl.boolean(startOffset, endOffset, irBuiltIns.booleanType, true), irResult
)
}
// If the constant true branch has empty body, it won't be converted. Thus, the entire `when` expression is effectively _not_
// exhaustive anymore. In that case, coerce the return type of `when` expression to Unit as per the backend expectation.
val irBranches = whenExpression.branches.mapNotNullTo(mutableListOf()) { branch ->
branch.takeIf {
it.condition !is FirElseIfTrueCondition || it.result.statements.isNotEmpty()
}?.toIrWhenBranch()
}
if (subjectVariable == null) {
irWhen
} else {
IrBlockImpl(startOffset, endOffset, irWhen.type, origin, listOf(subjectVariable, irWhen))
if (whenExpression.isExhaustive && whenExpression.branches.none { it.condition is FirElseIfTrueCondition }) {
val irResult = IrCallImpl(
startOffset, endOffset, irBuiltIns.nothingType,
irBuiltIns.noWhenBranchMatchedExceptionSymbol,
typeArgumentsCount = 0,
valueArgumentsCount = 0
)
irBranches += IrElseBranchImpl(
IrConstImpl.boolean(startOffset, endOffset, irBuiltIns.booleanType, true), irResult
)
}
generateWhen(
startOffset, endOffset, origin,
subjectVariable, irBranches,
whenExpression.isExhaustive && whenExpression.branches.none {
it.condition is FirElseIfTrueCondition && it.result.statements.isEmpty()
},
whenExpression.typeRef
)
}
}
}
private fun generateWhen(
startOffset: Int,
endOffset: Int,
origin: IrStatementOrigin?,
subjectVariable: IrVariable?,
branches: List<IrBranch>,
isEffectivelyExhaustive: Boolean,
resultTypeRef: FirTypeRef
): IrExpression {
val irWhen = IrWhenImpl(
startOffset, endOffset,
if (isEffectivelyExhaustive) resultTypeRef.toIrType() else irBuiltIns.unitType,
origin, branches
)
return if (subjectVariable == null) {
irWhen
} else {
IrBlockImpl(startOffset, endOffset, irWhen.type, origin, listOf(subjectVariable, irWhen))
}
}
private fun generateWhenSubjectVariable(whenExpression: FirWhenExpression): IrVariable? {
val subjectVariable = whenExpression.subjectVariable
val subjectExpression = whenExpression.subject
@@ -693,10 +703,10 @@ class Fir2IrVisitor(
}
}
override fun visitWhenBranch(whenBranch: FirWhenBranch, data: Any?): IrElement {
return whenBranch.convertWithOffsets { startOffset, endOffset ->
val condition = whenBranch.condition
val irResult = convertToIrExpression(whenBranch.result)
private fun FirWhenBranch.toIrWhenBranch(): IrBranch {
return convertWithOffsets { startOffset, endOffset ->
val condition = condition
val irResult = convertToIrExpression(result)
if (condition is FirElseIfTrueCondition) {
IrElseBranchImpl(IrConstImpl.boolean(irResult.startOffset, irResult.endOffset, irBuiltIns.booleanType, true), irResult)
} else {