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[embedded] Ignore 'do not specialize' @_semantics attributes in embedded Swift mode #70810

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Merged
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Jan 11, 2024
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[embedded] Ignore 'do not specialize' @_semantics attributes in embedded Swift mode #70810

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[embedded] Ignore 'do not specialize' @_semantics attributes in embed…
kubamracek Jan 10, 2024
62e8dc7
[embedded] Adjust embedded/specialize-attrs.swift test to include pri…
kubamracek Jan 10, 2024
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5 changes: 5 additions & 0 deletions lib/SILOptimizer/Utils/Generics.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -500,6 +500,11 @@ static bool createsInfiniteSpecializationLoop(ApplySite Apply) {

static bool shouldNotSpecialize(SILFunction *Callee, SILFunction *Caller,
SubstitutionMap Subs = {}) {
// Ignore "do not specialize" markers in embedded Swift -- specialization is
// mandatory.
if (Callee->getModule().getOptions().EmbeddedSwift)
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@zoecarver zoecarver Jan 10, 2024

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Would be nice if we could do this for perf annotations too, but that's probably a separate patch.

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@kubamracek kubamracek Jan 10, 2024

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Hm, I wonder if there is actually anything to fix for perf annotations: (1) The stdlib only has a handful of functions with the "do not specialize" marker and they seem to mostly be slow paths that do cause allocations (and thus are not going to be usable in @noLocks or @noAllocations code anyway). (2) Non-stdlib code probably shouldn't use the "do not specialize" marker as it's an underscored attribute, and arguably it could be considered to be the user's problem if they use the marker and then try to use such a code in a perf-annotated function...

return false;

if (Callee->hasSemanticsAttr(semantics::OPTIMIZE_SIL_SPECIALIZE_GENERIC_NEVER))
return true;

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29 changes: 29 additions & 0 deletions test/embedded/specialize-attrs.swift
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@@ -0,0 +1,29 @@
// RUN: %target-run-simple-swift(%S/Inputs/print.swift -parse-as-library -Onone -enable-experimental-feature Embedded -runtime-compatibility-version none -wmo -Xfrontend -disable-objc-interop -Xlinker -dead_strip) | %FileCheck %s
// RUN: %target-run-simple-swift(%S/Inputs/print.swift -parse-as-library -O -enable-experimental-feature Embedded -runtime-compatibility-version none -wmo -Xfrontend -disable-objc-interop -Xlinker -dead_strip) | %FileCheck %s
// RUN: %target-run-simple-swift(%S/Inputs/print.swift -parse-as-library -Osize -enable-experimental-feature Embedded -runtime-compatibility-version none -wmo -Xfrontend -disable-objc-interop -Xlinker -dead_strip) | %FileCheck %s

// REQUIRES: swift_in_compiler
// REQUIRES: executable_test
// REQUIRES: optimized_stdlib
// REQUIRES: OS=macosx

@_semantics("optimize.sil.specialize.generic.never")
func foo<T>(_ t: T) -> Int {
return 42
}

@_semantics("optimize.sil.specialize.generic.size.never")
func foo2<T>(_ t: T) -> Int {
return 42
}

@main
struct Main {
static func main() {
foo(42)
foo2(42)
print("OK!")
}
}

// CHECK: OK!