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Fix and improve stdlib optimizations

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This commit is contained in:
Karol Stasiak 2020-07-24 22:18:25 +02:00
parent ff03b50668
commit 9a67ac553d
6 changed files with 134 additions and 31 deletions
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2
docs/api/command-line.md
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@ -218,7 +218,7 @@ Default: yes.
* `-foptimize-stdlib`, `-fno-optimize-stdlib` –
Whether should replace some standard library calls with constant parameters with more efficient variants.
Currently affects `putstrz` and `strzlen`, but may affect more functions in the future.
Currently affects `putstrz`, `putpstr`, `strzlen`, `scrstrlen` and `pstrlen`, but may affect more functions in the future.
`.ini` equivalent: `optimize_stdlib`.
Default: no.

12
docs/stdlib/string.md
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@ -54,7 +54,7 @@ It contains functions for handling strings in the screen encoding with the same
## pstring
The `scrstring` module automatically imports the [`err` module](./other.md).
The `pstring` module automatically imports the [`err` module](./other.md).
It contains functions for handling length-prefixed strings in any 8-bit encoding.
@ -62,6 +62,14 @@ It contains functions for handling length-prefixed strings in any 8-bit encoding
#### `sbyte pstrcmp(pointer str1, pointer str2)`
#### `void pstrcopy(pointer dest, pointer src)`
#### `void pstrpaste(pointer dest, pointer src)`
#### `word pstr2word(pointer str)`
#### `void pstrappend(pointer buffer, pointer str)`
#### `void pstrappendchar(pointer buffer, byte char)`
#### `word pstr2word(pointer str)`
Converts a length-prefixed string to a number. Uses the default encoding.
Sets `errno`.
#### `word pscrstr2word(pointer str)`
Converts a length-prefixed string to a number. Uses the screen encoding.
Sets `errno`.

60
src/main/scala/millfork/compiler/AbstractStatementPreprocessor.scala
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@ -73,27 +73,36 @@ abstract class AbstractStatementPreprocessor(protected val ctx: CompilationConte
// stdlib:
if (optimizeStdlib) {
stmt match {
case ExpressionStatement(FunctionCallExpression("putstrz", List(TextLiteralExpression(text)))) =>
text.lastOption match {
case Some(LiteralExpression(0, _)) =>
text.size match {
case 1 =>
ctx.log.debug("Removing putstrz with empty argument", stmt.position)
return EmptyStatement(Nil) -> currentVarValues
case 2 =>
case ExpressionStatement(FunctionCallExpression("putstrz", List(TextLiteralExpression(text))))
if StdLibOptUtils.isValidNulTerminated(ctx.options.platform.defaultCodec, text) =>
text.size match {
case 1 =>
ctx.log.debug("Removing putstrz with empty argument", stmt.position)
return EmptyStatement(Nil) -> currentVarValues
case 2 =>
ctx.log.debug("Replacing putstrz with putchar", stmt.position)
return ExpressionStatement(FunctionCallExpression("putchar", List(text.head))) -> currentVarValues
case 3 =>
if (ctx.options.platform.cpuFamily == CpuFamily.M6502) {
ctx.log.debug("Replacing putstrz with putchar", stmt.position)
return ExpressionStatement(FunctionCallExpression("putchar", List(text.head))) -> currentVarValues
case 3 =>
if (ctx.options.platform.cpuFamily == CpuFamily.M6502) {
ctx.log.debug("Replacing putstrz with putchar", stmt.position)
return IfStatement(FunctionCallExpression("==", List(LiteralExpression(1, 1), LiteralExpression(1, 1))), List(
ExpressionStatement(FunctionCallExpression("putchar", List(text.head))),
ExpressionStatement(FunctionCallExpression("putchar", List(text(1))))
), Nil) -> currentVarValues
}
case _ =>
}
}
return IfStatement(FunctionCallExpression("==", List(LiteralExpression(1, 1), LiteralExpression(1, 1))), List(
ExpressionStatement(FunctionCallExpression("putchar", List(text.head))),
ExpressionStatement(FunctionCallExpression("putchar", List(text(1))))
), Nil) -> currentVarValues
}
case _ =>
}
case ExpressionStatement(FunctionCallExpression("putpstr", List(TextLiteralExpression(text))))
if StdLibOptUtils.isValidPascal(text) =>
text.length match {
case 1 =>
ctx.log.debug("Removing putpstr with empty argument", stmt.position)
return EmptyStatement(Nil) -> currentVarValues
case 2 =>
ctx.log.debug("Replacing putpstr with putchar", stmt.position)
return ExpressionStatement(FunctionCallExpression("putchar", List(text(1)))) -> currentVarValues
case _ =>
}
case _ =>
}
}
@ -360,12 +369,11 @@ abstract class AbstractStatementPreprocessor(protected val ctx: CompilationConte
if (optimizeStdlib) {
expr match {
case FunctionCallExpression("strzlen", List(TextLiteralExpression(text))) =>
text.lastOption match {
case Some(LiteralExpression(0, _)) if text.size <= 256 =>
ctx.log.debug("Replacing strzlen with constant argument", expr.position)
return LiteralExpression(text.size - 1, 1)
case _ =>
}
StdLibOptUtils.evalStrzLen(ctx, expr, ctx.options.platform.defaultCodec , text).foreach(return _)
case FunctionCallExpression("scrstrzlen", List(TextLiteralExpression(text))) =>
StdLibOptUtils.evalStrzLen(ctx, expr, ctx.options.platform.defaultCodec, text).foreach(return _)
case FunctionCallExpression("pstrlen", List(TextLiteralExpression(text))) =>
StdLibOptUtils.evalPStrLen(ctx, expr, text).foreach(return _)
case _ =>
}
}

67
src/main/scala/millfork/compiler/StdLibOptUtils.scala Normal file
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@ -0,0 +1,67 @@
package millfork.compiler
import millfork.node.{Expression, FunctionCallExpression, LiteralExpression}
import millfork.parser.TextCodec
/**
* @author Karol Stasiak
*/
object StdLibOptUtils {
private def fn(expr: Expression) = expr match {
case f: FunctionCallExpression => f.functionName
case _ => "library function call"
}
def isValidNulTerminated(codec: TextCodec, text: List[Expression], minLength: Int = 0, maxLength: Int = 255): Boolean = {
if (codec.stringTerminator.length != 1) return false
val Nul = codec.stringTerminator.head
if (text.init.forall {
case LiteralExpression(c, _) => c != Nul
case _ => false
}) {
text.lastOption match {
case Some(LiteralExpression(Nul, _)) if text.size >= minLength + 1 && text.size <= maxLength + 1 => return true
case _ =>
}
}
false
}
def isValidPascal(text: List[Expression]): Boolean = {
text.headOption match {
case Some(LiteralExpression(l, _)) if text.size == l + 1 && text.size <= 256 =>
true
case _ =>
false
}
}
def evalStrzLen(ctx: CompilationContext, expr: Expression, codec: TextCodec, text: List[Expression]): Option[Expression] = {
if (codec.stringTerminator.length != 1) return None
val Nul = codec.stringTerminator.head
if (text.init.forall {
case LiteralExpression(c, _) => c != Nul
case _ => false
}) {
text.lastOption match {
case Some(LiteralExpression(Nul, _)) if text.size <= 256 =>
ctx.log.debug(s"Replacing ${fn(expr)} with constant argument", expr.position)
return Some(LiteralExpression(text.size - 1, 1))
case _ =>
}
}
None
}
def evalPStrLen(ctx: CompilationContext, expr: Expression, text: List[Expression]): Option[Expression] = {
text.headOption match {
case Some(LiteralExpression(l, _)) if text.size == l + 1 && text.size <= 256 =>
ctx.log.debug(s"Replacing ${fn(expr)} with constant argument", expr.position)
return Some(LiteralExpression(l, 1))
case _ =>
}
None
}
}

16
src/test/resources/include/dummy_stdio.mfk
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@ -1,10 +1,22 @@
noinline void putchar(byte b) { }
noinline void putstrz(pointer p) { putchar(0) }
byte strzlen(pointer str) {
noinline void putpstr(pointer p) { putchar(0) }
noinline byte strzlen(pointer str) {
byte index
index = 0
while str[index] != 0 {
while str[index] != nullchar {
index += 1
}
return index
}
noinline byte scrstrzlen(pointer str) {
byte index
index = 0
while str[index] != nullchar_scr {
index += 1
}
return index
}
noinline byte pstrlen(pointer str) {
return str[0]
}

8
src/test/scala/millfork/test/StatementOptimizationSuite.scala
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@ -62,16 +62,24 @@ class StatementOptimizationSuite extends FunSuite with Matchers {
"""
| import stdio
| byte output @$c000
| byte output2 @$c002
| byte output3 @$c003
| void main() {
| output = strzlen("test"z)
| output2 = scrstrzlen("test"z)
| output3 = pstrlen("test"p)
| putstrz(""z)
| putstrz("a"z)
| putpstr(""p)
| putpstr("a"p)
| putstrz("bc"z)
| putstrz("def"z)
| }
""".stripMargin
) { m =>
m.readByte(0xc000) should equal(4)
m.readByte(0xc002) should equal(4)
m.readByte(0xc003) should equal(4)
}
}
}