IRGen: Add #_hasSymbol support for clang function decls and ObjC classes.

Resolves rdar://103408651.

Author: tshortli

include/swift/SIL/SILSymbolVisitor.h

@@ -128,6 +128,14 @@ class SILSymbolVisitor {
 
 template <typename F>
 void enumerateFunctionsForHasSymbol(SILModule &M, ValueDecl *D, F Handler) {
+  // Handle clang decls separately.
+  if (auto *clangDecl = D->getClangDecl()) {
+    if (isa<clang::FunctionDecl>(clangDecl))
+      Handler(SILDeclRef(D).asForeign());
+
+    return;
+  }
+
   class SymbolVisitor : public SILSymbolVisitor {
     F Handler;
 

lib/IRGen/GenHasSymbol.cpp

@@ -21,6 +21,8 @@
 #include "swift/SIL/SILFunctionBuilder.h"
 #include "swift/SIL/SILModule.h"
 #include "swift/SIL/SILSymbolVisitor.h"
+#include "clang/AST/DeclObjC.h"
+#include "clang/AST/GlobalDecl.h"
 
 #include "GenDecl.h"
 #include "IRGenFunction.h"
@@ -68,9 +70,8 @@ class HasSymbolIRGenVisitor : public IRSymbolVisitor {
     SILFunction *silFn = IGM.getSILModule().lookUpFunction(name);
     // Definitions for each SIL function should have been emitted by SILGen.
     assert(silFn && "missing SIL function?");
-    if (silFn) {
+    if (silFn)
       addFunction(silFn);
-    }
   }
 
 public:
@@ -111,6 +112,39 @@ class HasSymbolIRGenVisitor : public IRSymbolVisitor {
   }
 };
 
+static llvm::Constant *
+getAddrOfLLVMVariableForClangDecl(IRGenModule &IGM, ValueDecl *decl,
+                                  const clang::Decl *clangDecl) {
+  if (isa<clang::FunctionDecl>(clangDecl)) {
+    SILFunction *silFn =
+        IGM.getSILModule().lookUpFunction(SILDeclRef(decl).asForeign());
+    assert(silFn && "missing SIL function?");
+    return silFn ? IGM.getAddrOfSILFunction(silFn, NotForDefinition) : nullptr;
+  }
+
+  if (auto var = dyn_cast<clang::ObjCInterfaceDecl>(clangDecl))
+    return IGM.getAddrOfObjCClass(cast<ClassDecl>(decl), NotForDefinition);
+
+  llvm::report_fatal_error("Unexpected clang decl kind");
+}
+
+static void
+getSymbolAddrsForDecl(IRGenModule &IGM, ValueDecl *decl,
+                      llvm::SmallVector<llvm::Constant *, 4> &addrs) {
+  if (auto *clangDecl = decl->getClangDecl()) {
+    if (auto *addr = getAddrOfLLVMVariableForClangDecl(IGM, decl, clangDecl))
+      addrs.push_back(addr);
+    return;
+  }
+
+  SILSymbolVisitorOptions opts;
+  opts.VisitMembers = false;
+  auto silCtx = SILSymbolVisitorContext(IGM.getSwiftModule(), opts);
+  auto linkInfo = UniversalLinkageInfo(IGM);
+  auto symbolVisitorCtx = IRSymbolVisitorContext(linkInfo, silCtx);
+  HasSymbolIRGenVisitor(IGM, addrs).visit(decl, symbolVisitorCtx);
+}
+
 llvm::Function *IRGenModule::emitHasSymbolFunction(ValueDecl *decl) {
 
   PrettyStackTraceDecl trace("emitting #_hasSymbol query for", decl);
@@ -119,14 +153,9 @@ llvm::Function *IRGenModule::emitHasSymbolFunction(ValueDecl *decl) {
   auto func = cast<llvm::Function>(getOrCreateHelperFunction(
       mangler.mangleHasSymbolQuery(decl), Int1Ty, {},
       [decl, this](IRGenFunction &IGF) {
-        SILSymbolVisitorOptions opts;
-        opts.VisitMembers = false;
-        auto silCtx = SILSymbolVisitorContext(getSwiftModule(), opts);
-        auto linkInfo = UniversalLinkageInfo(*this);
-        auto symbolVisitorCtx = IRSymbolVisitorContext(linkInfo, silCtx);
         auto &Builder = IGF.Builder;
         llvm::SmallVector<llvm::Constant *, 4> addrs;
-        HasSymbolIRGenVisitor(*this, addrs).visit(decl, symbolVisitorCtx);
+        getSymbolAddrsForDecl(*this, decl, addrs);
 
         llvm::Value *ret = nullptr;
         for (llvm::Constant *addr : addrs) {

test/IRGen/Inputs/has_symbol_helper.swift renamed to test/IRGen/Inputs/has_symbol/has_symbol_helper.swift

@@ -0,0 +1,3 @@
+// NOTE: This header is used on platforms that do not support Obj-C.
+
+extern void clangFunc(int x);

test/IRGen/Inputs/has_symbol/has_symbol_helper_clang.h

@@ -0,0 +1,4 @@
+@import Foundation;
+
+@interface ObjCClass : NSObject
+@end

test/IRGen/Inputs/has_symbol/has_symbol_helper_objc.h

@@ -0,0 +1,9 @@
+module has_symbol_helper_clang {
+  header "has_symbol_helper_clang.h"
+  export *
+}
+
+module has_symbol_helper_objc {
+  header "has_symbol_helper_objc.h"
+  export *
+}

test/IRGen/Inputs/has_symbol/module.modulemap

@@ -1,6 +1,6 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -emit-module-path %t/has_symbol_helper.swiftmodule -parse-as-library %S/Inputs/has_symbol_helper.swift -enable-library-evolution -disable-availability-checking
-// RUN: %target-swift-frontend -emit-irgen %s -I %t -module-name test | %FileCheck %s
+// RUN: %target-swift-frontend -emit-module -emit-module-path %t/has_symbol_helper.swiftmodule -parse-as-library %S/Inputs/has_symbol/has_symbol_helper.swift -enable-library-evolution -disable-availability-checking
+// RUN: %target-swift-frontend -emit-irgen %s -I %t -I %S/Inputs/has_symbol -module-name test | %FileCheck %s
 
 // UNSUPPORTED: OS=windows-msvc
 

test/IRGen/has_symbol.swift

@@ -1,5 +1,5 @@
 // RUN: %empty-directory(%t)
-// RUN: %target-swift-frontend -emit-module -emit-module-path %t/has_symbol_helper.swiftmodule -parse-as-library %S/Inputs/has_symbol_helper.swift -enable-library-evolution -disable-availability-checking -DCONCURRENCY
+// RUN: %target-swift-frontend -emit-module -emit-module-path %t/has_symbol_helper.swiftmodule -parse-as-library %S/Inputs/has_symbol/has_symbol_helper.swift -enable-library-evolution -disable-availability-checking -DCONCURRENCY
 // RUN: %target-swift-frontend -emit-irgen %s -I %t -module-name test | %FileCheck %s
 
 // REQUIRES: concurrency

test/IRGen/has_symbol_async.swift

@@ -0,0 +1,15 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-irgen %s -I %t -I %S/Inputs/has_symbol -module-name test | %FileCheck %s
+
+// UNSUPPORTED: OS=windows-msvc
+
+@_weakLinked import has_symbol_helper_clang
+
+public func testClangDecls() {
+  // CHECK: %{{[0-9]+}} = call i1 @"$sSo9clangFuncyys5Int32VFTwS"()
+  if #_hasSymbol(clangFunc(_:)) {}
+}
+
+// --- clangFunc(_:) ---
+// CHECK: define linkonce_odr hidden i1 @"$sSo9clangFuncyys5Int32VFTwS"() #1 {
+// CHECK:   ret i1 icmp ne (void (i32)* @clangFunc, void (i32)* null)

test/IRGen/has_symbol_clang.swift

@@ -0,0 +1,14 @@
+// RUN: %empty-directory(%t)
+// RUN: %target-swift-frontend -emit-irgen %s -I %t -I %S/Inputs/has_symbol -module-name test | %FileCheck %s
+
+// REQUIRES: objc_interop
+
+@_weakLinked import has_symbol_helper_objc
+
+public func testClassTypes() {
+  // CHECK: %{{[0-9]+}} = call i1 @"$sSo9ObjCClassCTwS"()
+  if #_hasSymbol(ObjCClass.self) {}
+}
+
+// CHECK: define linkonce_odr hidden i1 @"$sSo9ObjCClassCTwS"()
+// CHECK:   ret i1 icmp ne (%objc_class* @"OBJC_CLASS_$_ObjCClass", %objc_class* null)