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7b2a6e5e8d
This matches how dispatch_once works in C, dramatically cutting the cost of a global accessor by avoiding the runtime call in the hot path and giving the global a unique branch for the CPU to predict away. For now, only do this for Darwin; non-ObjC platforms don't necessarily expose their "done" value as ABI like ours do. While we're here, change "once" to take a thin function pointer. We don't ever emit global initializers with context dependencies, and this simplifies the runtime glue between swift_once and dispatch_once/std::call_once a bit. Swift SVN r28166
54 lines
2.3 KiB
Swift
54 lines
2.3 KiB
Swift
// RUN: %target-swift-frontend -parse-as-library -emit-silgen %s | FileCheck %s
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// CHECK: sil private @globalinit_[[T:.*]]_func0 : $@convention(thin) () -> () {
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// CHECK: [[XADDR:%.*]] = global_addr @_Tv12lazy_globals1xSi : $*Int
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// CHECK: store {{%.*}} to [[XADDR]] : $*Int
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// CHECK: sil hidden [global_init] @_TF12lazy_globalsau1xSi : $@convention(thin) () -> Builtin.RawPointer {
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// CHECK: [[TOKEN_ADDR:%.*]] = global_addr @globalinit_[[T]]_token0 : $*Builtin.Word
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// CHECK: [[TOKEN_PTR:%.*]] = address_to_pointer [[TOKEN_ADDR]] : $*Builtin.Word to $Builtin.RawPointer
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// CHECK: [[INIT_FUNC:%.*]] = function_ref @globalinit_[[T]]_func0 : $@convention(thin) () -> ()
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// CHECK: builtin "once"([[TOKEN_PTR]] : $Builtin.RawPointer, [[INIT_FUNC]] : $@convention(thin) () -> ()) : $()
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// CHECK: [[GLOBAL_ADDR:%.*]] = global_addr @_Tv12lazy_globals1xSi : $*Int
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// CHECK: [[GLOBAL_PTR:%.*]] = address_to_pointer [[GLOBAL_ADDR]] : $*Int to $Builtin.RawPointer
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// CHECK: return [[GLOBAL_PTR]] : $Builtin.RawPointer
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// CHECK: }
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var x: Int = 0
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struct Foo {
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// CHECK: sil hidden [global_init] @_TFV12lazy_globals3Fooau3fooSi : $@convention(thin) () -> Builtin.RawPointer {
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static var foo: Int = 22
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static var computed: Int {
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return 33
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}
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static var initialized: Int = 57
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}
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enum Bar {
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// CHECK: sil hidden [global_init] @_TFO12lazy_globals3Barau3barSi : $@convention(thin) () -> Builtin.RawPointer {
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static var bar: Int = 33
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}
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// We only emit one initializer function per pattern binding, which initializes
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// all of the bound variables.
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func f() -> (Int, Int) { return (1, 2) }
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// CHECK: sil private @globalinit_[[T]]_func4 : $@convention(thin) () -> () {
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// CHECK: function_ref @_TF12lazy_globals1fFT_TSiSi_ : $@convention(thin) () -> (Int, Int)
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// CHECK: sil hidden [global_init] @_TF12lazy_globalsau2a1Si : $@convention(thin) () -> Builtin.RawPointer
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// CHECK: function_ref @globalinit_[[T]]_func4 : $@convention(thin) () -> ()
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// CHECK: global_addr @_Tv12lazy_globals2a1Si : $*Int
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// CHECK: sil hidden [global_init] @_TF12lazy_globalsau2b1Si : $@convention(thin) () -> Builtin.RawPointer {
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// CHECK: function_ref @globalinit_[[T]]_func4 : $@convention(thin) () -> ()
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// CHECK: global_addr @_Tv12lazy_globals2b1Si : $*Int
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var (a1, b1) = f()
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var computed: Int {
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return 44
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}
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var initialized: Int = 57
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