[AutoDiff] Add differentiability witness SILGen test.

test/AutoDiff/sil_differentiability_witness_silgen.swift

@@ -0,0 +1,112 @@
+// RUN: %target-swift-frontend -emit-silgen %s | %target-sil-opt | %FileCheck %s
+
+// Test SIL differentiability witness SIL generation.
+
+// Test public non-generic function.
+// SIL differentiability witness:
+// - Has public linkage (implicit).
+// - Has no `where` clause.
+
+public func foo(_ x: Float) -> Float { x }
+
+@differentiating(foo)
+public func foo_jvp(_ x: Float) -> (value: Float, differential: (Float) -> Float) {
+  (x, { $0 })
+}
+
+@differentiating(foo)
+public func foo_vjp(_ x: Float) -> (value: Float, pullback: (Float) -> Float) {
+  (x, { $0 })
+}
+
+// CHECK-LABEL: // differentiability witness for foo(_:)
+// CHECK-NEXT: sil_differentiability_witness [parameters 0] [results 0] @$s36sil_differentiability_witness_silgen3fooyS2fF : $@convention(thin) (Float) -> Float {
+// CHECK-NEXT:   jvp: @AD__$s36sil_differentiability_witness_silgen3fooyS2fF__jvp_src_0_wrt_0 : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float)
+// CHECK-NEXT:   vjp: @AD__$s36sil_differentiability_witness_silgen3fooyS2fF__vjp_src_0_wrt_0 : $@convention(thin) (Float) -> (Float, @owned @callee_guaranteed (Float) -> Float)
+// CHECK-NEXT: }
+
+// Test internal non-generic function.
+// SIL differentiability witness:
+// - Has hidden linkage.
+// - Has no `where` clause.
+// - Has only VJP.
+
+func bar<T>(_ x: Float, _ y: T) -> Float { x }
+
+@differentiating(bar)
+public func bar_jvp<T>(_ x: Float, _ y: T) -> (value: Float, differential: (Float) -> Float) {
+  (x, { $0 })
+}
+
+// CHECK-LABEL: // differentiability witness for bar<A>(_:_:)
+// CHECK-NEXT: sil_differentiability_witness hidden [parameters 0] [results 0] @$s36sil_differentiability_witness_silgen3baryS2f_xtlF : $@convention(thin) <T> (Float, @in_guaranteed T) -> Float {
+// CHECK-NEXT:   jvp: @AD__$s36sil_differentiability_witness_silgen3baryS2f_xtlF__jvp_src_0_wrt_0 : $@convention(thin) <τ_0_0> (Float, @in_guaranteed τ_0_0) -> (Float, @owned @callee_guaranteed (Float) -> Float)
+// CHECK-NEXT: }
+
+// Test internal generic function.
+// SIL differentiability witness:
+// - Has hidden linkage.
+// - Has `where` clause.
+
+@differentiable(where T: Differentiable)
+func generic<T>(_ x: T, _ y: Float) -> T { x }
+
+@differentiating(generic)
+func generic_jvp<T: Differentiable>(_ x: T, _ y: Float) -> (
+  value: T, differential: (T.TangentVector, Float) -> T.TangentVector
+) {
+  (x, { dx, dy in dx })
+}
+
+@differentiating(generic)
+func generic_vjp<T: Differentiable>(_ x: T, _ y: Float) -> (
+  value: T, pullback: (T.TangentVector) -> (T.TangentVector, Float)
+) {
+  (x, { ($0, .zero) })
+}
+
+// CHECK-LABEL: // differentiability witness for generic<A>(_:_:)
+// CHECK-NEXT: sil_differentiability_witness hidden [parameters 0 1] [results 0] [where T : _Differentiable] @$s36sil_differentiability_witness_silgen7genericyxx_SftlF : $@convention(thin) <T> (@in_guaranteed T, Float) -> @out T {
+// CHECK-NEXT:   jvp: @AD__$s36sil_differentiability_witness_silgen7genericyxx_SftlF__jvp_src_0_wrt_0_1 : $@convention(thin) <τ_0_0 where τ_0_0 : _Differentiable> (@in_guaranteed τ_0_0, Float) -> (@out τ_0_0, @owned @callee_guaranteed (@in_guaranteed τ_0_0.TangentVector, Float) -> @out τ_0_0.TangentVector)
+// CHECK-NEXT:   vjp: @AD__$s36sil_differentiability_witness_silgen7genericyxx_SftlF__vjp_src_0_wrt_0_1 : $@convention(thin) <τ_0_0 where τ_0_0 : _Differentiable> (@in_guaranteed τ_0_0, Float) -> (@out τ_0_0, @owned @callee_guaranteed (@in_guaranteed τ_0_0.TangentVector) -> (@out τ_0_0.TangentVector, Float))
+// CHECK-NEXT: }
+
+public struct Foo: Differentiable {
+  public var x: Float
+
+  @differentiable
+  public init(_ x: Float) {
+    self.x = x
+  }
+
+// CHECK-LABEL: // differentiability witness for Foo.init(_:)
+// CHECK-NEXT: sil_differentiability_witness [parameters 0] [results 0] @$s36sil_differentiability_witness_silgen3FooVyACSfcfC : $@convention(method) (Float, @thin Foo.Type) -> Foo {
+// CHECK-NEXT: }
+
+  @differentiable
+  public func method() -> Float {
+    x
+  }
+
+// CHECK-LABEL: // differentiability witness for Foo.method()
+// CHECK-NEXT: sil_differentiability_witness [parameters 0] [results 0] @$s36sil_differentiability_witness_silgen3FooV6methodSfyF : $@convention(method) (Foo) -> Float {
+// CHECK-NEXT: }
+
+  @differentiable
+  public var computedProperty: Float {
+    x
+  }
+
+// CHECK-LABEL: // differentiability witness for Foo.computedProperty.getter
+// CHECK-NEXT: sil_differentiability_witness [parameters 0] [results 0] @$s36sil_differentiability_witness_silgen3FooV16computedPropertySfvg : $@convention(method) (Foo) -> Float {
+// CHECK-NEXT: }
+
+  @differentiable
+  public subscript() -> Float {
+    x
+  }
+
+// CHECK-LABEL: // differentiability witness for Foo.subscript.getter
+// CHECK-NEXT: sil_differentiability_witness [parameters 0] [results 0] @$s36sil_differentiability_witness_silgen3FooVSfycig : $@convention(method) (Foo) -> Float {
+// CHECK-NEXT: }
+}