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Switch when to phi. (#172)

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This commit is contained in:
Nikolay Igotti
2016-12-29 16:33:23 +03:00
committed by GitHub
parent c15fb6833d
commit 667d3b9356
4 changed files with 46 additions and 30 deletions
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backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/IrToBitcode.kt
+28 -30
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@@ -1146,28 +1146,29 @@ internal class CodeGeneratorVisitor(val context: Context) : IrElementVisitorVoid
private fun evaluateWhen(expression: IrWhen): LLVMValueRef {
context.log("evaluateWhen : ${ir2string(expression)}")
var bbExit: LLVMBasicBlockRef? = null // By default "when" does not have "exit".
if (!KotlinBuiltIns.isNothing(expression.type)) // If "when" has "exit".
bbExit = codegen.basicBlock() // Create basic block to process "exit".
val isUnit = KotlinBuiltIns.isUnit(expression.type)
val isNothing = KotlinBuiltIns.isNothing(expression.type)
val neitherUnitNorNothing = !isNothing && !isUnit
val tmpLlvmVariable = if (!isUnit) codegen.vars.createAnonymousMutable(expression.type) else -1
expression.branches.forEach { // Iterate through "when" branches (clauses).
var bbNext = bbExit // For last clause bbNext coincides with bbExit.
if (it != expression.branches.last()) // If it is not last clause.
bbNext = codegen.basicBlock() // Create new basic block for next clause.
val isUnitBranch = KotlinBuiltIns.isUnit(it.result.type)
val isNothingBranch = KotlinBuiltIns.isNothing(it.result.type)
generateWhenCase(isUnitBranch, isNothingBranch, tmpLlvmVariable, it, bbNext, bbExit) // Generate code for current clause.
if (!isNothing) // If "when" has "exit".
bbExit = codegen.basicBlock() // Create basic block to process "exit".
val resultPhi = if (isUnit || isNothing) null else
codegen.appendingTo(bbExit!!) {
codegen.phi(codegen.getLLVMType(expression.type))
}
expression.branches.forEach { // Iterate through "when" branches (clauses).
var bbNext = bbExit // For last clause bbNext coincides with bbExit.
if (it != expression.branches.last()) // If it is not last clause.
bbNext = codegen.basicBlock() // Create new basic block for next clause.
generateWhenCase(resultPhi, it, bbNext, bbExit) // Generate code for current clause.
}
return when {
// FIXME: remove the hacks.
isUnit -> codegen.theUnitInstanceRef.llvm
isNothing -> codegen.kNothingFakeValue
else -> codegen.vars.load(tmpLlvmVariable)
else -> resultPhi!!
}
}
@@ -1760,30 +1761,27 @@ internal class CodeGeneratorVisitor(val context: Context) : IrElementVisitorVoid
//-------------------------------------------------------------------------//
private fun generateWhenCase(isUnit:Boolean, isNothing:Boolean, resultPtr: Int,
branch: IrBranch, bbNext: LLVMBasicBlockRef?, bbExit: LLVMBasicBlockRef?) {
val neitherUnitNorNothing = !isNothing && !isUnit // If branches doesn't end with 'return' either result hasn't got 'unit' type.
private fun generateWhenCase(resultPhi: LLVMValueRef?, branch: IrBranch,
bbNext: LLVMBasicBlockRef?, bbExit: LLVMBasicBlockRef?) {
val branchResult = branch.result
// TODO: use phis here!
if (isUnconditional(branch)) { // It is the "else" clause.
val brResult = evaluateExpression(branchResult) // Generate clause body.
if (neitherUnitNorNothing) // If nor unit neither result ends with return
codegen.vars.store(brResult, resultPtr) // we store result to temporal variable.
if (bbExit == null) return // If 'bbExit' isn't defined just return
codegen.br(bbExit) // Generate branch to bbExit.
codegen.positionAtEnd(bbExit) // Switch generation to bbExit.
val isNothing = KotlinBuiltIns.isNothing(branchResult.type)
val brResult = if (isUnconditional(branch)) { // It is the "else" clause.
evaluateExpression(branchResult) // Generate clause body.
} else { // It is conditional clause.
val bbCurr = codegen.basicBlock() // Create block for clause body.
val condition = evaluateExpression(branch.condition) // Generate cmp instruction.
codegen.condBr(condition, bbCurr, bbNext) // Conditional branch depending on cmp result.
codegen.positionAtEnd(bbCurr) // Switch generation to block for clause body.
val brResult = evaluateExpression(branch.result) // Generate clause body.
if (neitherUnitNorNothing) // If nor unit neither result ends with return
codegen.vars.store(brResult, resultPtr) // we store result to temporal variable.
if (!isNothing) // If basic block doesn't end with 'return'
codegen.br(bbExit!!) // generate branch to bbExit.
codegen.positionAtEnd(bbNext!!) // Switch generation to bbNextClause.
evaluateExpression(branch.result) // Generate clause body.
}
if (resultPhi != null && !isNothing)
codegen.assignPhis(resultPhi to brResult)
if (bbExit != null && !isNothing)
codegen.br(bbExit!!)
if (bbNext != null) // Switch generation to next or exit.
codegen.positionAtEnd(bbNext)
else if (bbExit != null)
codegen.positionAtEnd(bbExit)
}
//-------------------------------------------------------------------------//
backend.native/tests/build.gradle
+8
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@@ -279,6 +279,14 @@ task when5(type: RunKonanTest) {
source = "codegen/branching/when5.kt"
}
task when6(type: RunKonanTest) {
source = "codegen/branching/when6.kt"
}
task when7(type: RunKonanTest) {
source = "codegen/branching/when7.kt"
}
task when_through(type: RunKonanTest) {
source = "codegen/branching/when_through.kt"
}
backend.native/tests/codegen/branching/when6.kt
+6
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@@ -0,0 +1,6 @@
fun foo() {
}
fun main(args: Array<String>) {
if (true) foo() else foo()
}
backend.native/tests/codegen/branching/when7.kt
+4
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@@ -0,0 +1,4 @@
fun main(args: Array<String>) {
val b = args.size < 1
val x = if (b) Any() else throw Error()
}