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[SILGen] Remove subtle identity function call. #67846

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Merged
merged 4 commits into from
Aug 10, 2023
Merged

[SILGen] Remove subtle identity function call. #67846

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6e26b41
[SILGen] Gardening: Moved comment.
nate-chandler Aug 8, 2023
c8d1ea5
[SILGen] Gardening: Line wrapping.
nate-chandler Aug 8, 2023
e894a34
[SILGen] Gardening: Deleted comment.
nate-chandler Aug 9, 2023
368536c
[SILGen] Remove subtle identity function call.
nate-chandler Aug 8, 2023
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30 changes: 13 additions & 17 deletions lib/SILGen/SILGenFunction.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -795,18 +795,14 @@ void SILGenFunction::emitCaptures(SILLocation loc,
case CaptureKind::Box: {
assert(!isPack);

auto entryValue = getAddressValue(val, /*forceCopy=*/false);
// LValues are captured as both the box owning the value and the
// address of the value.
assert(entryValue->getType().isAddress() && "no address for captured var!");
assert(val->getType().isAddress() &&
"no address for captured var!");
// Boxes of opaque return values stay opaque.
auto minimalLoweredType = SGM.Types.getLoweredRValueType(
TypeExpansionContext::minimal(), type->getCanonicalType());
// If this is a boxed variable, we can use it directly.
if (Entry.box &&
entryValue->getType().getASTType() == minimalLoweredType) {
// If our captured value is a box with a moveonlywrapped type inside,
// unwrap it.
val->getType().getASTType() == minimalLoweredType) {
auto box = ManagedValue::forBorrowedObjectRValue(Entry.box);
// We can guarantee our own box to the callee.
if (canGuarantee) {
Expand All @@ -815,6 +811,8 @@ void SILGenFunction::emitCaptures(SILLocation loc,
box = box.copy(*this, loc);
}

// If our captured value is a box with a moveonlywrapped type inside,
// unwrap it.
if (box.getType().isBoxedMoveOnlyWrappedType(&F)) {
CleanupCloner cloner(*this, box);
box = cloner.clone(
Expand All @@ -824,7 +822,7 @@ void SILGenFunction::emitCaptures(SILLocation loc,
capturedArgs.push_back(box);

if (captureCanEscape)
escapesToMark.push_back(entryValue);
escapesToMark.push_back(val);
} else {
// Address only 'let' values are passed by box. This isn't great, in
// that a variable captured by multiple closures will be boxed for each
Expand All @@ -838,12 +836,13 @@ void SILGenFunction::emitCaptures(SILLocation loc,
// in-place.
// TODO: Use immutable box for immutable captures.
auto boxTy = SGM.Types.getContextBoxTypeForCapture(
vd, minimalLoweredType, FunctionDC->getGenericEnvironmentOfContext(),
vd, minimalLoweredType,
FunctionDC->getGenericEnvironmentOfContext(),
/*mutable*/ true);

AllocBoxInst *allocBox = B.createAllocBox(loc, boxTy);
ProjectBoxInst *boxAddress = B.createProjectBox(loc, allocBox, 0);
B.createCopyAddr(loc, entryValue, boxAddress, IsNotTake,
B.createCopyAddr(loc, val, boxAddress, IsNotTake,
IsInitialization);
if (canGuarantee)
capturedArgs.push_back(
Expand All @@ -857,17 +856,14 @@ void SILGenFunction::emitCaptures(SILLocation loc,
case CaptureKind::ImmutableBox: {
assert(!isPack);

auto entryValue = getAddressValue(val, /*forceCopy=*/false);
// LValues are captured as both the box owning the value and the
// address of the value.
assert(entryValue->getType().isAddress() &&
assert(val->getType().isAddress() &&
"no address for captured var!");
// Boxes of opaque return values stay opaque.
auto minimalLoweredType = SGM.Types.getLoweredRValueType(
TypeExpansionContext::minimal(), type->getCanonicalType());
// If this is a boxed variable, we can use it directly.
if (Entry.box &&
entryValue->getType().getASTType() == minimalLoweredType) {
val->getType().getASTType() == minimalLoweredType) {
// We can guarantee our own box to the callee.
if (canGuarantee) {
capturedArgs.push_back(
Expand All @@ -876,7 +872,7 @@ void SILGenFunction::emitCaptures(SILLocation loc,
capturedArgs.push_back(emitManagedRetain(loc, Entry.box));
}
if (captureCanEscape)
escapesToMark.push_back(entryValue);
escapesToMark.push_back(val);
} else {
// Address only 'let' values are passed by box. This isn't great, in
// that a variable captured by multiple closures will be boxed for each
Expand All @@ -896,7 +892,7 @@ void SILGenFunction::emitCaptures(SILLocation loc,

AllocBoxInst *allocBox = B.createAllocBox(loc, boxTy);
ProjectBoxInst *boxAddress = B.createProjectBox(loc, allocBox, 0);
B.createCopyAddr(loc, entryValue, boxAddress, IsNotTake,
B.createCopyAddr(loc, val, boxAddress, IsNotTake,
IsInitialization);
if (canGuarantee)
capturedArgs.push_back(
Expand Down