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Saleem Abdulrasool
08a3d1862e
Add a [copy] attribute to unconditional_checked_cast_addr to preserve its source and initialize an independently owned destination. Failure still terminates execution through the runtime's cast diagnostic. This expresses forced casts from borrowed storage without first copying the source or introducing a conditional cast and a separate failure path. Store the flag in SILNode's shared byte and preserve it through serialization, cloning, and differentiation. Casts without [copy] retain the existing consuming behavior.
30 lines
1.0 KiB
Plaintext
30 lines
1.0 KiB
Plaintext
// RUN: %target-swift-frontend -emit-ir %s | %FileCheck %s
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// RUN: %target-swift-frontend -O -emit-ir %s | %FileCheck %s
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sil_stage canonical
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import Swift
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// Unconditional alone: preserve the source, and diagnose failure in the runtime.
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// CHECK-LABEL: define {{.*}}@copy_source(
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// CHECK: call {{.*}}@swift_dynamicCast({{.*}}i{{32|64}} 1)
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// CHECK-NOT: @swift_dynamicCast
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// CHECK: ret void
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sil @copy_source : $@convention(thin) <T, U> (@in_guaranteed T) -> @out U {
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bb0(%0 : $*U, %1 : $*T):
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unconditional_checked_cast_addr [copy] T in %1 : $*T to U in %0 : $*U
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%2 = tuple ()
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return %2 : $()
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}
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// Unconditional | TakeOnSuccess | DestroyOnFailure: existing consuming behavior.
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// CHECK-LABEL: define {{.*}}@take_source(
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// CHECK: call {{.*}}@swift_dynamicCast({{.*}}i{{32|64}} 7)
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// CHECK-NOT: @swift_dynamicCast
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// CHECK: ret void
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sil @take_source : $@convention(thin) <T, U> (@in T) -> @out U {
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bb0(%0 : $*U, %1 : $*T):
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unconditional_checked_cast_addr T in %1 : $*T to U in %0 : $*U
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%2 = tuple ()
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return %2 : $()
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}
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