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DougGregorDougGregor
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Merge pull request #84682 from DougGregor/embedded-deferred-code-gen-external-symbols
2 parents 9fa9ea7 + cc519a0 commit cd7924a

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‎include/swift/SIL/SILDeclRef.h‎

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Original file line numberDiff line numberDiff line change
@@ -415,6 +415,10 @@ struct SILDeclRef {
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/// embedded linkage model.
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bool hasNonUniqueDefinition() const;
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/// True if the declaration is explicitly marked as being exposed to a
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/// foreign language or environment,
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static bool declExposedToForeignLanguage(const ValueDecl *decl);
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/// True if the declaration should have a non-unique definition based on the
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/// embedded linkage model.
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static bool declHasNonUniqueDefinition(const ValueDecl *decl);

‎lib/SIL/IR/SILDeclRef.cpp‎

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@@ -1153,6 +1153,29 @@ bool SILDeclRef::hasNonUniqueDefinition() const {
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return false;
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}
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bool SILDeclRef::declExposedToForeignLanguage(const ValueDecl *decl) {
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// @c / @_cdecl / @objc.
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if (decl->getAttrs().hasAttribute<CDeclAttr>() ||
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(decl->getAttrs().hasAttribute<ObjCAttr>() &&
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decl->getDeclContext()->isModuleScopeContext())) {
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return true;
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}
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// @_expose that isn't negated.
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for (auto *expose : decl->getAttrs().getAttributes<ExposeAttr>()) {
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switch (expose->getExposureKind()) {
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case ExposureKind::Cxx:
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case ExposureKind::Wasm:
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return true;
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case ExposureKind::NotCxx:
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continue;
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}
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}
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return false;
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}
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bool SILDeclRef::declHasNonUniqueDefinition(const ValueDecl *decl) {
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// This function only forces the issue in embedded.
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if (!decl->getASTContext().LangOpts.hasFeature(Feature::Embedded))
@@ -1167,6 +1190,28 @@ bool SILDeclRef::declHasNonUniqueDefinition(const ValueDecl *decl) {
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if (decl->getAttrs().hasAttribute<AlwaysEmitIntoClientAttr>())
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return true;
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// If the declaration is marked in a manner that indicates that other
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// systems will expect it to have a symbol, then it has a unique definition.
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// There are a few cases here.
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// - @implementation explicitly says that we are implementing something to
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// be called from another language, so call it non-unique.
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if (decl->isObjCImplementation())
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return false;
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// - @c / @_cdecl / @objc / @_expose expect to be called from another
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// language if the symbol itself would be visible.
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if (declExposedToForeignLanguage(decl) &&
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decl->getFormalAccess() >= AccessLevel::Internal) {
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return false;
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}
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// - @_section and @_used imply that external tools will look for this symbol.
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if (decl->getAttrs().hasAttribute<SectionAttr>() ||
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decl->getAttrs().hasAttribute<UsedAttr>()) {
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return false;
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}
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auto module = decl->getModuleContext();
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auto &ctx = module->getASTContext();
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‎lib/SIL/IR/SILFunction.cpp‎

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Original file line numberDiff line numberDiff line change
@@ -1069,6 +1069,18 @@ SILFunction::isPossiblyUsedExternally() const {
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if (markedAsUsed())
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return true;
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// If this function is exposed to a foreign language, it can be used
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// externally (by that language).
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if (auto decl = getDeclRef().getDecl()) {
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if (SILDeclRef::declExposedToForeignLanguage(decl))
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return true;
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}
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// If this function was explicitly placed in a section or given a WebAssembly
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// export, it can be used externally.
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if (!Section.empty() || !WasmExportName.empty())
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return true;
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if (shouldBePreservedForDebugger())
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return true;
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‎lib/SIL/IR/SILGlobalVariable.cpp‎

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Original file line numberDiff line numberDiff line change
@@ -91,6 +91,9 @@ bool SILGlobalVariable::isPossiblyUsedExternally() const {
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if (markedAsUsed())
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return true;
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if (getSectionAttr())
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return true;
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SILLinkage linkage = getLinkage();
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return swift::isPossiblyUsedExternally(linkage, getModule().isWholeModule());
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}

‎test/embedded/linkage/Inputs/MyModuleExports.h‎

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@@ -0,0 +1,4 @@
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double clib_func1(void);
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double clib_func2(void);
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double clib_func3(void);
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double clib_func4(void);

‎test/embedded/linkage/Inputs/module.modulemap‎

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Original file line numberDiff line numberDiff line change
@@ -1,3 +1,7 @@
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module CDependency {
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header "CHeader.h"
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}
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module MyModuleExports {
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header "MyModuleExports.h"
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}

‎test/embedded/linkage/c.swift‎

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// Check that C functions are exported as needed.
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// REQUIRES: swift_in_compiler
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// REQUIRES: executable_test
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// REQUIRES: swift_feature_Embedded
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// REQUIRES: swift_feature_DeferredCodeGen
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// REQUIRES: swift_feature_CDecl
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// REQUIRES: swift_feature_CImplementation
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// REQUIRES: swift_feature_SymbolLinkageMarkers
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// RUN: %target-swift-frontend -emit-ir -o - %s -I %S/Inputs -package-name MyPackage -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -enable-experimental-feature CDecl -enable-experimental-feature CImplementation -enable-experimental-feature SymbolLinkageMarkers -parse-as-library | %FileCheck %s
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import MyModuleExports
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// ---------------------------------------------------------------------------
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// @c / @_cdecl on > internal declarations cause symbol emission
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// ---------------------------------------------------------------------------
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// CHECK: define {{(protected |dllexport )?}}void @lib_publicCDeclFunc()
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@_cdecl("lib_publicCDeclFunc")
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public func f1() { }
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// CHECK: define {{(protected |dllexport )?}}void @lib_publicCFunc()
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@c(lib_publicCFunc)
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package func f2() { }
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// CHECK: define hidden void @lib_publicCDeclFunc3
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@_cdecl("lib_publicCDeclFunc3")
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internal func f3() { }
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// CHECK: define hidden void @lib_publicCDeclFunc4
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@c("lib_publicCDeclFunc4")
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internal func f4() { }
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// CHECK-NOT: lib_publicCDeclFunc5
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@_cdecl("lib_publicCDeclFunc5")
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private func f5() { }
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// CHECK-NOT: lib_publicCDeclFunc6
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@c("lib_publicCDeclFunc6")
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private func f6() { }
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// ---------------------------------------------------------------------------
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// @implementation @c / @_cdecl cause symbol emission
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// ---------------------------------------------------------------------------
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// CHECK: define {{(protected |dllexport )?}}double @clib_func1
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@_cdecl("clib_func1") @implementation
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public func clib_func1() -> Double { 0 }
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// CHECK: define {{(protected |dllexport )?}}double @clib_func2
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@c @implementation
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package func clib_func2() -> Double { 0 }
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// CHECK: define hidden double @clib_func3
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@_cdecl("clib_func3") @implementation
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internal func clib_func3() -> Double { 0 }
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// CHECK: define hidden double @clib_func4
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@c @implementation
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internal func clib_func4() -> Double { 0 }
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// ---------------------------------------------------------------------------
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// @_section causes symbol emission
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// ---------------------------------------------------------------------------
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// CHECK: define {{(protected |dllexport )?}}swiftcc void @"$e1c15symbolInSectionyyF"
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@_section("__TEXT,__mysection")
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public func symbolInSection() { }
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// CHECK: define hidden swiftcc void @"$e1c23internalSymbolInSectionyyF"
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@_section("__TEXT,__mysection")
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func internalSymbolInSection() { }
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// ---------------------------------------------------------------------------
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// @_used causes symbol emission
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// ---------------------------------------------------------------------------
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// CHECK: define hidden swiftcc void @"$e1c10usedSymbolyyF"
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@_used
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func usedSymbol() { }

‎test/embedded/linkage/cxx.swift‎

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@@ -0,0 +1,16 @@
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// Check that C++ functions are exported as needed.
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// REQUIRES: swift_in_compiler
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// REQUIRES: executable_test
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// REQUIRES: swift_feature_Embedded
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// REQUIRES: swift_feature_DeferredCodeGen
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// RUN: %target-swift-frontend -emit-ir -o - %s -I %S/Inputs -package-name MyPackage -enable-experimental-feature Embedded -enable-experimental-feature DeferredCodeGen -parse-as-library -cxx-interoperability-mode=default | %FileCheck %s
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// CHECK: define hidden swiftcc void @"$e3cxx2f1yyF"()
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@_expose(Cxx)
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func f1() { }
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// CHECK-NOT: 2f2
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@_expose(!Cxx)
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public func f2() { }

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