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Fixing the strong imported async frame pointer flags #40035

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Merged
merged 2 commits into from
Nov 10, 2021
Merged

Fixing the strong imported async frame pointer flags #40035

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1e7ce90
Fixing the strong imported async frame pointer flags
etcwilde Nov 3, 2021
3e2c5a6
Make it LinkOnceODRLinkage
etcwilde Nov 3, 2021
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13 changes: 13 additions & 0 deletions lib/IRGen/IRGenModule.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1834,6 +1834,19 @@ void IRGenModule::emitSwiftAsyncExtendedFrameInfoWeakRef() {
extendedFramePointerFlagsWeakRef = new llvm::GlobalVariable(Module, Int8PtrTy, false,
llvm::GlobalValue::ExternalWeakLinkage, nullptr,
symbolName);

// The weak imported extendedFramePointerFlagsWeakRef gets optimized out
// before being added back as a strong import.
// Declarations can't be added to the used list, so we create a little
// global that can't be used from the program, but can be in the used list to
// avoid optimizations.
llvm::GlobalVariable *usage = new llvm::GlobalVariable(
Module, extendedFramePointerFlagsWeakRef->getType(), false,
llvm::GlobalValue::LinkOnceODRLinkage,
static_cast<llvm::GlobalVariable *>(extendedFramePointerFlagsWeakRef),
"_swift_async_extendedFramePointerFlagsUser");
usage->setVisibility(llvm::GlobalValue::HiddenVisibility);
addUsedGlobal(usage);
}

bool IRGenModule::isConcurrencyAvailable() {
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8 changes: 8 additions & 0 deletions test/Concurrency/Backdeploy/weak_linking.swift
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Expand Up @@ -3,6 +3,9 @@
// RUN: %FileCheck %s --check-prefix=NEW < %t/new.ir
// RUN: %target-swift-frontend %s -target x86_64-apple-macosx10.15 -module-name main -emit-ir -o %t/old.ir -disable-availability-checking
// RUN: %FileCheck %s --check-prefix=OLD < %t/old.ir
// RUN: %target-swift-frontend %s -target x86_64-apple-macosx10.15 -O -module-name main -emit-ir -o %t/optimized.ir -disable-availability-checking
// RUN: %FileCheck %s --check-prefix=OPTIMIZED < %t/optimized.ir


// REQUIRES: OS=macosx

Expand All @@ -12,6 +15,11 @@
// OLD: declare extern_weak swiftcc %swift.metadata_response @"$sScPMa"
// OLD: declare extern_weak swiftcc i8 @"$sScP8rawValues5UInt8Vvg"

// OPTIMIZED: @swift_async_extendedFramePointerFlags = extern_weak global i8*
// OPTIMIZED: @_swift_async_extendedFramePointerFlagsUser = linkonce_odr hidden global i8** @swift_async_extendedFramePointerFlags
// OPTIMIZED: @llvm.used =
// OPTIMIZED-SAME: (i8*** @_swift_async_extendedFramePointerFlagsUser to i8*)

@available(macOS 12.0, *)
public func g() async -> String { "hello" }

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