prog8/compiler/test/TestOptimization.kt

package prog8tests

import io.kotest.assertions.fail
import io.kotest.assertions.withClue
import io.kotest.core.spec.style.FunSpec
import io.kotest.matchers.shouldBe
import io.kotest.matchers.shouldNotBe
import io.kotest.matchers.types.instanceOf
import io.kotest.matchers.types.shouldBeSameInstanceAs
import prog8.ast.Program
import prog8.ast.base.DataType
import prog8.ast.base.ParentSentinel
import prog8.ast.base.Position
import prog8.ast.expressions.*
import prog8.ast.statements.*
import prog8.compiler.BeforeAsmGenerationAstChanger
import prog8.compiler.printAst
import prog8.compiler.target.C64Target
import prog8.compilerinterface.*
import prog8tests.helpers.DummyFunctions
import prog8tests.helpers.DummyMemsizer
import prog8tests.helpers.DummyStringEncoder
import prog8tests.helpers.ErrorReporterForTests
import prog8tests.helpers.assertSuccess
import prog8tests.helpers.compileText
import prog8tests.helpers.generateAssembly

class TestOptimization: FunSpec({
    test("testRemoveEmptySubroutineExceptStart") {
        val sourcecode = """
            main {
                sub start() {
                }
                sub empty() {
                    ; going to be removed
                }
            }
        """
        val result = compileText(C64Target, true, sourcecode).assertSuccess()
        val toplevelModule = result.program.toplevelModule
        val mainBlock = toplevelModule.statements.single() as Block
        val startSub = mainBlock.statements.single() as Subroutine
        result.program.entrypoint shouldBeSameInstanceAs startSub
        withClue("only start sub should remain") {
            startSub.name shouldBe "start"
        }
        withClue("compiler has inserted return in empty subroutines") {
            startSub.statements.single() shouldBe instanceOf<Return>()
        }
    }

    test("testDontRemoveEmptySubroutineIfItsReferenced") {
        val sourcecode = """
            main {
                sub start() {
                    uword xx = &empty
                    xx++
                }
                sub empty() {
                    ; should not be removed
                }
            }
        """
        val result = compileText(C64Target, true, sourcecode).assertSuccess()
        val toplevelModule = result.program.toplevelModule
        val mainBlock = toplevelModule.statements.single() as Block
        val startSub = mainBlock.statements[0] as Subroutine
        val emptySub = mainBlock.statements[1] as Subroutine
        result.program.entrypoint shouldBeSameInstanceAs startSub
        startSub.name shouldBe "start"
        emptySub.name shouldBe "empty"
        withClue("compiler has inserted return in empty subroutines") {
            emptySub.statements.single() shouldBe instanceOf<Return>()
        }
    }

    test("testGeneratedConstvalueInheritsProperParentLinkage") {
        val number = NumericLiteralValue(DataType.UBYTE, 11, Position.DUMMY)
        val tc = TypecastExpression(number, DataType.BYTE, false, Position.DUMMY)
        val program = Program("test", DummyFunctions, DummyMemsizer, DummyStringEncoder)
        tc.linkParents(ParentSentinel)
        tc.parent shouldNotBe null
        number.parent shouldNotBe null
        tc shouldBeSameInstanceAs number.parent
        val constvalue = tc.constValue(program)!!
        constvalue shouldBe instanceOf<NumericLiteralValue>()
        constvalue.number.toInt() shouldBe 11
        constvalue.type shouldBe DataType.BYTE
        tc shouldBeSameInstanceAs constvalue.parent
    }

    test("testConstantFoldedAndSilentlyTypecastedForInitializerValues") {
        val sourcecode = """
            main {
                sub start() {
                    const ubyte TEST = 10
                    byte @shared x1 = TEST as byte + 1
                    byte @shared x2 = 1 + TEST as byte
                    ubyte @shared y1 = TEST + 1 as byte
                    ubyte @shared y2 = 1 as byte + TEST
                }
            }
        """
        val result = compileText(C64Target, true, sourcecode).assertSuccess()
        val mainsub = result.program.entrypoint
        mainsub.statements.size shouldBe 10
        val declTest = mainsub.statements[0] as VarDecl
        val declX1 = mainsub.statements[1] as VarDecl
        val initX1 = mainsub.statements[2] as Assignment
        val declX2 = mainsub.statements[3] as VarDecl
        val initX2 = mainsub.statements[4] as Assignment
        val declY1 = mainsub.statements[5] as VarDecl
        val initY1 = mainsub.statements[6] as Assignment
        val declY2 = mainsub.statements[7] as VarDecl
        val initY2 = mainsub.statements[8] as Assignment
        mainsub.statements[9] shouldBe instanceOf<Return>()
        (declTest.value as NumericLiteralValue).number.toDouble() shouldBe 10.0
        declX1.value shouldBe null
        declX2.value shouldBe null
        declY1.value shouldBe null
        declY2.value shouldBe null
        (initX1.value as NumericLiteralValue).type shouldBe DataType.BYTE
        (initX1.value as NumericLiteralValue).number.toDouble() shouldBe 11.0
        (initX2.value as NumericLiteralValue).type shouldBe DataType.BYTE
        (initX2.value as NumericLiteralValue).number.toDouble() shouldBe 11.0
        (initY1.value as NumericLiteralValue).type shouldBe DataType.UBYTE
        (initY1.value as NumericLiteralValue).number.toDouble() shouldBe 11.0
        (initY2.value as NumericLiteralValue).type shouldBe DataType.UBYTE
        (initY2.value as NumericLiteralValue).number.toDouble() shouldBe 11.0
    }

    test("typecasted assignment from ubyte logical expressoin to uword var") {
        val src = """
            main {
                sub start() {
                    ubyte bb
                    uword ww
                    ww = not bb or not ww       ; expression combining ubyte and uword
                }
            }
        """
        val result = compileText(C64Target, false, src, writeAssembly = false).assertSuccess()

        // ww = ((( not bb as uword)  or  not ww) as uword)
        val wwAssign = result.program.entrypoint.statements.last() as Assignment
        val expr = wwAssign.value as TypecastExpression

        wwAssign.target.identifier?.nameInSource shouldBe listOf("ww")
        expr.type shouldBe DataType.UWORD
        expr.expression.inferType(result.program).istype(DataType.UBYTE) shouldBe true
    }

    test("intermediate assignment steps have correct types for codegen phase (BeforeAsmGenerationAstChanger)") {
        val src = """
            main {
                sub start() {
                    ubyte bb
                    uword ww
                    bb = not bb or not ww       ; expression combining ubyte and uword
                }
            }
        """
        val result = compileText(C64Target, false, src, writeAssembly = false).assertSuccess()

        // bb = (( not bb as uword)  or  not ww)
        val bbAssign = result.program.entrypoint.statements.last() as Assignment
        val expr = bbAssign.value as BinaryExpression
        expr.operator shouldBe "or"
        expr.left shouldBe instanceOf<TypecastExpression>() // casted to word
        expr.right shouldBe instanceOf<PrefixExpression>()
        expr.left.inferType(result.program).getOrElse { fail("dt") } shouldBe DataType.UWORD
        expr.right.inferType(result.program).getOrElse { fail("dt") } shouldBe DataType.UWORD
        expr.inferType(result.program).getOrElse { fail("dt") } shouldBe DataType.UBYTE

        val options = CompilationOptions(OutputType.RAW, LauncherType.NONE, ZeropageType.DONTUSE, emptyList(), false, true, C64Target)
        val changer = BeforeAsmGenerationAstChanger(result.program,
            options,
            ErrorReporterForTests()
        )

        changer.visit(result.program)
        while(changer.applyModifications()>0) {
            changer.visit(result.program)
        }

        // assignment is now split into:
        //     bb =  not bb
        //     bb = (bb or  not ww)

        val assigns = result.program.entrypoint.statements.filterIsInstance<Assignment>()
        val bbAssigns = assigns.filter { it.value !is NumericLiteralValue }
        bbAssigns.size shouldBe 2

        bbAssigns[0].target.identifier!!.nameInSource shouldBe listOf("bb")
        bbAssigns[0].value shouldBe instanceOf<PrefixExpression>()
        (bbAssigns[0].value as PrefixExpression).operator shouldBe "not"
        (bbAssigns[0].value as PrefixExpression).expression shouldBe IdentifierReference(listOf("bb"), Position.DUMMY)
        bbAssigns[0].value.inferType(result.program).getOrElse { fail("dt") } shouldBe DataType.UBYTE

        bbAssigns[1].target.identifier!!.nameInSource shouldBe listOf("bb")
        val bbAssigns1expr = bbAssigns[1].value as BinaryExpression
        bbAssigns1expr.operator shouldBe "or"
        bbAssigns1expr.left shouldBe IdentifierReference(listOf("bb"), Position.DUMMY)
        bbAssigns1expr.right shouldBe instanceOf<PrefixExpression>()
        (bbAssigns1expr.right as PrefixExpression).operator shouldBe "not"
        (bbAssigns1expr.right as PrefixExpression).expression shouldBe IdentifierReference(listOf("ww"), Position.DUMMY)
        bbAssigns1expr.inferType(result.program).getOrElse { fail("dt") } shouldBe DataType.UBYTE

        val asm = generateAssembly(result.program, options)
        asm.valid shouldBe true
    }

    test("intermediate assignment steps generated for typecasted expression") {
        val src = """
            main {
                sub start() {
                    ubyte r
                    ubyte @shared bb = (cos8(r)/2 + 100) as ubyte
                }
            }
        """
        val result = compileText(C64Target, true, src, writeAssembly = true).assertSuccess()
        /* turned into:
        ubyte r
        r = 0
        ubyte bb
        prog8_lib.retval_interm_b = cos8(r)
        prog8_lib.retval_interm_b >>= 1
        prog8_lib.retval_interm_b += 100
        bb = prog8_lib.retval_interm_b
        return
         */
        val st = result.program.entrypoint.statements
        st.size shouldBe 8
        st.last() shouldBe instanceOf<Return>()
        var assign = st[3] as Assignment
        assign.target.identifier!!.nameInSource shouldBe listOf("prog8_lib","retval_interm_b")
        assign = st[4] as Assignment
        assign.target.identifier!!.nameInSource shouldBe listOf("prog8_lib","retval_interm_b")
        assign = st[5] as Assignment
        assign.target.identifier!!.nameInSource shouldBe listOf("prog8_lib","retval_interm_b")
        assign = st[6] as Assignment
        assign.target.identifier!!.nameInSource shouldBe listOf("bb")
    }

    test("asmgen correctly deals with float typecasting in augmented assignment") {
        val src="""
            %option enable_floats
            
            main {
                sub start() {
                    ubyte ub
                    float ff
                    ff += (ub as float)         ; operator doesn't matter
                }
            }
        """
        val result1 = compileText(C64Target, optimize=false, src, writeAssembly = false).assertSuccess()

        val assignYY = result1.program.entrypoint.statements.last() as Assignment
        assignYY.isAugmentable shouldBe true
        assignYY.target.identifier!!.nameInSource shouldBe listOf("ff")
        val value = assignYY.value as BinaryExpression
        value.operator shouldBe "+"
        value.left shouldBe IdentifierReference(listOf("ff"), Position.DUMMY)
        value.right shouldBe instanceOf<TypecastExpression>()

        val asm = generateAssembly(result1.program)
        asm.valid shouldBe true
    }

    test("unused variable removal") {
        val src="""
            main {
                sub start() {
                    ubyte unused
                    ubyte @shared unused_but_shared     ; this one should remain
                    ubyte usedvar_only_written
                    usedvar_only_written=2
                    usedvar_only_written++
                    ubyte usedvar                       ; and this one too
                    usedvar = msb(usedvar)
                }
            }
        """
        val result = compileText(C64Target, optimize=true, src, writeAssembly=false).assertSuccess()
        result.program.entrypoint.statements.size shouldBe 4       // unused_but_shared decl, unused_but_shared=0,  usedvar decl, usedvar assign
        val (decl, assign, decl2, assign2) = result.program.entrypoint.statements
        decl shouldBe instanceOf<VarDecl>()
        (decl as VarDecl).name shouldBe "unused_but_shared"
        assign shouldBe instanceOf<Assignment>()
        decl2 shouldBe instanceOf<VarDecl>()
        (decl2 as VarDecl).name shouldBe "usedvar"
        assign2 shouldBe instanceOf<Assignment>()
    }

    test("unused variable removal from subscope") {
        val src="""
            main {
                sub start()  {
                    if cx16.r0 {
                        uword xx = 42       ; to be removed
                        xx=99               ; to be removed
                        cx16.r0 = 0
                    }
                    func2()
            
                    sub func2() {
                         uword yy = 33      ; to be removed
                         yy=99              ; to be removed
                         cx16.r0 = 0
                    }
                }
            }"""
        val result = compileText(C64Target, optimize=true, src, writeAssembly=false).assertSuccess()
        result.program.entrypoint.statements.size shouldBe 3
        val ifstmt = result.program.entrypoint.statements[0] as IfStatement
        ifstmt.truepart.statements.size shouldBe 1
        (ifstmt.truepart.statements[0] as Assignment).target.identifier!!.nameInSource shouldBe listOf("cx16", "r0")
        val func2 = result.program.entrypoint.statements[2] as Subroutine
        func2.statements.size shouldBe 1
        (func2.statements[0] as Assignment).target.identifier!!.nameInSource shouldBe listOf("cx16", "r0")
    }
})