Skip to content

Commit fdad63e

Browse files
oderskyodersky
authored
Merge pull request #24 from dotty-staging/add-errorhandling-stack-handled-by-backend
Add errorhandling stack handled by backend
2 parents 0c1b9b5 + 009d623 commit fdad63e

File tree

4 files changed

+101
-19
lines changed

4 files changed

+101
-19
lines changed

‎compiler/src/dotty/tools/backend/jvm/BCodeBodyBuilder.scala

Lines changed: 74 additions & 17 deletions
Original file line numberDiff line numberDiff line change
@@ -4,7 +4,7 @@ package jvm
44

55
import scala.language.unsafeNulls
66

7-
import scala.annotation.switch
7+
import scala.annotation.{switch, tailrec}
88
import scala.collection.mutable.SortedMap
99

1010
import scala.tools.asm
@@ -79,9 +79,14 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
7979

8080
tree match {
8181
case Assign(lhs @ DesugaredSelect(qual, _), rhs) =>
82+
val savedStackHeight = stackHeight
8283
val isStatic = lhs.symbol.isStaticMember
83-
if (!isStatic) { genLoadQualifier(lhs) }
84+
if (!isStatic) {
85+
genLoadQualifier(lhs)
86+
stackHeight += 1
87+
}
8488
genLoad(rhs, symInfoTK(lhs.symbol))
89+
stackHeight = savedStackHeight
8590
lineNumber(tree)
8691
// receiverClass is used in the bytecode to access the field. using sym.owner may lead to IllegalAccessError
8792
val receiverClass = qual.tpe.typeSymbol
@@ -145,7 +150,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
145150
}
146151

147152
genLoad(larg, resKind)
153+
stackHeight += resKind.size
148154
genLoad(rarg, if (isShift) INT else resKind)
155+
stackHeight -= resKind.size
149156

150157
(code: @switch) match {
151158
case ADD => bc add resKind
@@ -182,14 +189,19 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
182189
if (isArrayGet(code)) {
183190
// load argument on stack
184191
assert(args.length == 1, s"Too many arguments for array get operation: $tree");
192+
stackHeight += 1
185193
genLoad(args.head, INT)
194+
stackHeight -= 1
186195
generatedType = k.asArrayBType.componentType
187196
bc.aload(elementType)
188197
}
189198
else if (isArraySet(code)) {
190199
val List(a1, a2) = args
200+
stackHeight += 1
191201
genLoad(a1, INT)
202+
stackHeight += 1
192203
genLoad(a2)
204+
stackHeight -= 2
193205
generatedType = UNIT
194206
bc.astore(elementType)
195207
} else {
@@ -223,7 +235,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
223235
val resKind = if (hasUnitBranch) UNIT else tpeTK(tree)
224236

225237
val postIf = new asm.Label
226-
genLoadTo(thenp, resKind, LoadDestination.Jump(postIf))
238+
genLoadTo(thenp, resKind, LoadDestination.Jump(postIf, stackHeight))
227239
markProgramPoint(failure)
228240
genLoadTo(elsep, resKind, LoadDestination.FallThrough)
229241
markProgramPoint(postIf)
@@ -482,7 +494,17 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
482494
dest match
483495
case LoadDestination.FallThrough =>
484496
()
485-
case LoadDestination.Jump(label) =>
497+
case LoadDestination.Jump(label, targetStackHeight) =>
498+
if targetStackHeight < stackHeight then
499+
val stackDiff = stackHeight - targetStackHeight
500+
if expectedType == UNIT then
501+
bc dropMany stackDiff
502+
else
503+
val loc = locals.makeTempLocal(expectedType)
504+
bc.store(loc.idx, expectedType)
505+
bc dropMany stackDiff
506+
bc.load(loc.idx, expectedType)
507+
end if
486508
bc goTo label
487509
case LoadDestination.Return =>
488510
bc emitRETURN returnType
@@ -577,7 +599,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
577599
if dest == LoadDestination.FallThrough then
578600
val resKind = tpeTK(tree)
579601
val jumpTarget = new asm.Label
580-
registerJumpDest(labelSym, resKind, LoadDestination.Jump(jumpTarget))
602+
registerJumpDest(labelSym, resKind, LoadDestination.Jump(jumpTarget, stackHeight))
581603
genLoad(expr, resKind)
582604
markProgramPoint(jumpTarget)
583605
resKind
@@ -635,7 +657,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
635657
markProgramPoint(loop)
636658

637659
if isInfinite then
638-
val dest = LoadDestination.Jump(loop)
660+
val dest = LoadDestination.Jump(loop, stackHeight)
639661
genLoadTo(body, UNIT, dest)
640662
dest
641663
else
@@ -650,7 +672,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
650672
val failure = new asm.Label
651673
genCond(cond, success, failure, targetIfNoJump = success)
652674
markProgramPoint(success)
653-
genLoadTo(body, UNIT, LoadDestination.Jump(loop))
675+
genLoadTo(body, UNIT, LoadDestination.Jump(loop, stackHeight))
654676
markProgramPoint(failure)
655677
end match
656678
LoadDestination.FallThrough
@@ -744,7 +766,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
744766

745767
// scala/bug#10290: qual can be `this.$outer()` (not just `this`), so we call genLoad (not just ALOAD_0)
746768
genLoad(superQual)
769+
stackHeight += 1
747770
genLoadArguments(args, paramTKs(app))
771+
stackHeight -= 1
748772
generatedType = genCallMethod(fun.symbol, InvokeStyle.Super, app.span)
749773

750774
// 'new' constructor call: Note: since constructors are
@@ -766,7 +790,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
766790
assert(classBTypeFromSymbol(ctor.owner) == rt, s"Symbol ${ctor.owner.showFullName} is different from $rt")
767791
mnode.visitTypeInsn(asm.Opcodes.NEW, rt.internalName)
768792
bc dup generatedType
793+
stackHeight += 2
769794
genLoadArguments(args, paramTKs(app))
795+
stackHeight -= 2
770796
genCallMethod(ctor, InvokeStyle.Special, app.span)
771797

772798
case _ =>
@@ -799,8 +825,12 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
799825
else if (app.hasAttachment(BCodeHelpers.UseInvokeSpecial)) InvokeStyle.Special
800826
else InvokeStyle.Virtual
801827

802-
if (invokeStyle.hasInstance) genLoadQualifier(fun)
828+
val savedStackHeight = stackHeight
829+
if invokeStyle.hasInstance then
830+
genLoadQualifier(fun)
831+
stackHeight += 1
803832
genLoadArguments(args, paramTKs(app))
833+
stackHeight = savedStackHeight
804834

805835
val DesugaredSelect(qual, name) = fun: @unchecked // fun is a Select, also checked in genLoadQualifier
806836
val isArrayClone = name == nme.clone_ && qual.tpe.widen.isInstanceOf[JavaArrayType]
@@ -858,6 +888,8 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
858888
bc iconst elems.length
859889
bc newarray elmKind
860890

891+
stackHeight += 3 // during the genLoad below, there is the result, its dup, and the index
892+
861893
var i = 0
862894
var rest = elems
863895
while (!rest.isEmpty) {
@@ -869,6 +901,8 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
869901
i = i + 1
870902
}
871903

904+
stackHeight -= 3
905+
872906
generatedType
873907
}
874908

@@ -883,7 +917,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
883917
val (generatedType, postMatch, postMatchDest) =
884918
if dest == LoadDestination.FallThrough then
885919
val postMatch = new asm.Label
886-
(tpeTK(tree), postMatch, LoadDestination.Jump(postMatch))
920+
(tpeTK(tree), postMatch, LoadDestination.Jump(postMatch, stackHeight))
887921
else
888922
(expectedType, null, dest)
889923

@@ -1160,14 +1194,21 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
11601194
}
11611195

11621196
def genLoadArguments(args: List[Tree], btpes: List[BType]): Unit =
1163-
args match
1164-
case arg :: args1 =>
1165-
btpes match
1166-
case btpe :: btpes1 =>
1167-
genLoad(arg, btpe)
1168-
genLoadArguments(args1, btpes1)
1169-
case _ =>
1170-
case _ =>
1197+
@tailrec def loop(args: List[Tree], btpes: List[BType]): Unit =
1198+
args match
1199+
case arg :: args1 =>
1200+
btpes match
1201+
case btpe :: btpes1 =>
1202+
genLoad(arg, btpe)
1203+
stackHeight += btpe.size
1204+
loop(args1, btpes1)
1205+
case _ =>
1206+
case _ =>
1207+
1208+
val savedStackHeight = stackHeight
1209+
loop(args, btpes)
1210+
stackHeight = savedStackHeight
1211+
end genLoadArguments
11711212

11721213
def genLoadModule(tree: Tree): BType = {
11731214
val module = (
@@ -1266,11 +1307,14 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
12661307
}.sum
12671308
bc.genNewStringBuilder(approxBuilderSize)
12681309

1310+
stackHeight += 1 // during the genLoad below, there is a reference to the StringBuilder on the stack
12691311
for (elem <- concatArguments) {
12701312
val elemType = tpeTK(elem)
12711313
genLoad(elem, elemType)
12721314
bc.genStringBuilderAppend(elemType)
12731315
}
1316+
stackHeight -= 1
1317+
12741318
bc.genStringBuilderEnd
12751319
} else {
12761320

@@ -1287,12 +1331,15 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
12871331
var totalArgSlots = 0
12881332
var countConcats = 1 // ie. 1 + how many times we spilled
12891333

1334+
val savedStackHeight = stackHeight
1335+
12901336
for (elem <- concatArguments) {
12911337
val tpe = tpeTK(elem)
12921338
val elemSlots = tpe.size
12931339

12941340
// Unlikely spill case
12951341
if (totalArgSlots + elemSlots >= MaxIndySlots) {
1342+
stackHeight = savedStackHeight + countConcats
12961343
bc.genIndyStringConcat(recipe.toString, argTypes.result(), constVals.result())
12971344
countConcats += 1
12981345
totalArgSlots = 0
@@ -1317,8 +1364,10 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
13171364
val tpe = tpeTK(elem)
13181365
argTypes += tpe.toASMType
13191366
genLoad(elem, tpe)
1367+
stackHeight += 1
13201368
}
13211369
}
1370+
stackHeight = savedStackHeight
13221371
bc.genIndyStringConcat(recipe.toString, argTypes.result(), constVals.result())
13231372

13241373
// If we spilled, generate one final concat
@@ -1513,7 +1562,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
15131562
} else {
15141563
val tk = tpeTK(l).maxType(tpeTK(r))
15151564
genLoad(l, tk)
1565+
stackHeight += tk.size
15161566
genLoad(r, tk)
1567+
stackHeight -= tk.size
15171568
genCJUMP(success, failure, op, tk, targetIfNoJump)
15181569
}
15191570
}
@@ -1628,7 +1679,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
16281679
}
16291680

16301681
genLoad(l, ObjectRef)
1682+
stackHeight += 1
16311683
genLoad(r, ObjectRef)
1684+
stackHeight -= 1
16321685
genCallMethod(equalsMethod, InvokeStyle.Static)
16331686
genCZJUMP(success, failure, Primitives.NE, BOOL, targetIfNoJump)
16341687
}
@@ -1644,7 +1697,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
16441697
} else if (isNonNullExpr(l)) {
16451698
// SI-7852 Avoid null check if L is statically non-null.
16461699
genLoad(l, ObjectRef)
1700+
stackHeight += 1
16471701
genLoad(r, ObjectRef)
1702+
stackHeight -= 1
16481703
genCallMethod(defn.Any_equals, InvokeStyle.Virtual)
16491704
genCZJUMP(success, failure, Primitives.NE, BOOL, targetIfNoJump)
16501705
} else {
@@ -1654,7 +1709,9 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
16541709
val lNonNull = new asm.Label
16551710

16561711
genLoad(l, ObjectRef)
1712+
stackHeight += 1
16571713
genLoad(r, ObjectRef)
1714+
stackHeight -= 1
16581715
locals.store(eqEqTempLocal)
16591716
bc dup ObjectRef
16601717
genCZJUMP(lNull, lNonNull, Primitives.EQ, ObjectRef, targetIfNoJump = lNull)

‎compiler/src/dotty/tools/backend/jvm/BCodeIdiomatic.scala

Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -620,6 +620,16 @@ trait BCodeIdiomatic {
620620
// can-multi-thread
621621
final def drop(tk: BType): Unit = { emit(if (tk.isWideType) Opcodes.POP2 else Opcodes.POP) }
622622

623+
// can-multi-thread
624+
final def dropMany(size: Int): Unit = {
625+
var s = size
626+
while s >= 2 do
627+
emit(Opcodes.POP2)
628+
s -= 2
629+
if s > 0 then
630+
emit(Opcodes.POP)
631+
}
632+
623633
// can-multi-thread
624634
final def dup(tk: BType): Unit = { emit(if (tk.isWideType) Opcodes.DUP2 else Opcodes.DUP) }
625635

‎compiler/src/dotty/tools/backend/jvm/BCodeSkelBuilder.scala

Lines changed: 12 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -45,7 +45,7 @@ trait BCodeSkelBuilder extends BCodeHelpers {
4545
/** The value is put on the stack, and control flows through to the next opcode. */
4646
case FallThrough
4747
/** The value is put on the stack, and control flow is transferred to the given `label`. */
48-
case Jump(label: asm.Label)
48+
case Jump(label: asm.Label, targetStackHeight: Int)
4949
/** The value is RETURN'ed from the enclosing method. */
5050
case Return
5151
/** The value is ATHROW'n. */
@@ -368,6 +368,8 @@ trait BCodeSkelBuilder extends BCodeHelpers {
368368
// used by genLoadTry() and genSynchronized()
369369
var earlyReturnVar: Symbol = null
370370
var shouldEmitCleanup = false
371+
// stack tracking
372+
var stackHeight = 0
371373
// line numbers
372374
var lastEmittedLineNr = -1
373375

@@ -504,6 +506,13 @@ trait BCodeSkelBuilder extends BCodeHelpers {
504506
loc
505507
}
506508

509+
def makeTempLocal(tk: BType): Local =
510+
assert(nxtIdx != -1, "not a valid start index")
511+
assert(tk.size > 0, "makeLocal called for a symbol whose type is Unit.")
512+
val loc = Local(tk, "temp", nxtIdx, isSynth = true)
513+
nxtIdx += tk.size
514+
loc
515+
507516
// not to be confused with `fieldStore` and `fieldLoad` which also take a symbol but a field-symbol.
508517
def store(locSym: Symbol): Unit = {
509518
val Local(tk, _, idx, _) = slots(locSym)
@@ -574,6 +583,8 @@ trait BCodeSkelBuilder extends BCodeHelpers {
574583
earlyReturnVar = null
575584
shouldEmitCleanup = false
576585

586+
stackHeight = 0
587+
577588
lastEmittedLineNr = -1
578589
}
579590

‎compiler/src/dotty/tools/dotc/transform/DropBreaks.scala

Lines changed: 5 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -162,7 +162,7 @@ class DropBreaks extends MiniPhase, RecordStackChange:
162162
* source and target of the jump
163163
*/
164164
protected def stackChange(using Context) =
165-
if enclosingBoundaries == 0 then ctx else shadowLabels
165+
ctx // if enclosingBoundaries == 0 then ctx else shadowLabels
166166

167167
/** Need to suppress labeled returns if there is an intervening try
168168
*/
@@ -178,6 +178,10 @@ class DropBreaks extends MiniPhase, RecordStackChange:
178178
case Break(_, _) => ctx
179179
case _ => stackChange
180180

181+
override def prepareForValDef(tree: ValDef)(using Context): Context =
182+
if tree.symbol.is(Lazy) && tree.symbol.owner == ctx.owner.enclosingMethod then shadowLabels
183+
else ctx
184+
181185
// other stack changing operations are handled in RecordStackChange
182186

183187
/** If `tree` is a BreakBoundary, transform it as follows:

0 commit comments

Comments
 (0)