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SILGen: Don't crash on withoutActuallyEscaping of objc blocks #15393

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Merged
merged 2 commits into from
Mar 21, 2018
Merged

SILGen: Don't crash on withoutActuallyEscaping of objc blocks #15393

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19d3a4d
Test case for withoutActuallyEscaping of blocks
aschwaighofer Mar 21, 2018
eac5f83
SILGen: Don't crash on withoutActuallyEscaping of objc blocks
aschwaighofer Mar 21, 2018
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22 changes: 22 additions & 0 deletions lib/SILGen/SILGenExpr.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -5480,6 +5480,28 @@ RValue RValueEmitter::visitMakeTemporarilyEscapableExpr(
visit(E->getNonescapingClosureValue()).getAsSingleValue(SGF, E);

auto escapingFnTy = SGF.getLoweredType(E->getOpaqueValue()->getType());
auto silFnTy = escapingFnTy.castTo<SILFunctionType>();

// Handle @convention(block). No withoutActuallyEscaping verification yet.
if (silFnTy->getExtInfo().getRepresentation() !=
SILFunctionTypeRepresentation::Thick) {
RValue rvalue;
auto escapingClosure =
SGF.emitManagedRValueWithCleanup(SGF.B.createConvertFunction(
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Can you use SILGenFunction APIs instead of doing this by hand here?

E, functionValue.ensurePlusOne(SGF, E).forward(SGF), escapingFnTy));
// Bind the opaque value to the escaping function.
SILGenFunction::OpaqueValueState opaqueValue{
escapingClosure,
/*consumable*/ true,
/*hasBeenConsumed*/ false,
};
SILGenFunction::OpaqueValueRAII pushOpaqueValue(SGF, E->getOpaqueValue(),
opaqueValue);

// Emit the guarded expression.
rvalue = visit(E->getSubExpr(), C);
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Why not just return this rather than assign to rvalue.

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Will cleanup in follow-up commit.

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SGTM

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#15402

return rvalue;
}

// Convert it to an escaping function value.
auto escapingClosure =
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26 changes: 26 additions & 0 deletions test/SILGen/without_actually_escaping_block.swift
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@@ -0,0 +1,26 @@
// RUN: %target-swift-frontend -module-name without_actually_escaping -emit-silgen -enable-sil-ownership %s | %FileCheck %s

// REQUIRES: objc_interop

import Foundation

typealias Callback = @convention(block) () -> Void

// CHECK-LABEL: sil {{.*}} @$S25without_actually_escaping9testBlock5blockyyyXB_tF
// CHECK: bb0([[ARG:%.*]] : @guaranteed $@convention(block) @noescape () -> ()):
// CHECK: [[C1:%.*]] = copy_block [[ARG]]
// CHECK: [[B1:%.*]] = begin_borrow [[C1]]
// CHECK: [[C2:%.*]] = copy_value [[B1]]
// CHECK: [[CVT:%.*]] = convert_function [[C2]] : $@convention(block) @noescape () -> () to $@convention(block) () -> ()
// CHECK: [[B2:%.*]] = begin_borrow [[CVT]]
// CHECK: [[FN:%.*]] = function_ref @$S25without_actually_escaping9testBlock5blockyyyXB_tFyyyXBXEfU_
// CHECK: apply [[FN]]([[B2]])
// CHECK: end_borrow [[B2]] from [[CVT]]
// CHECK: destroy_value [[CVT]]
// CHECK: end_borrow [[B1]] from [[C1]]
// CHECK: destroy_value [[C1]]
// CHECK: return

func testBlock(block: Callback) {
withoutActuallyEscaping(block) { $0() }
}