-fvisibility=hidden: Hide init symbols, TypeInfos and vtables too if the associated aggregate isn't exported (#3129)

gen/declarations.cpp

@@ -146,7 +146,7 @@ public:
       auto &initZ = ir->getInitSymbol();
       auto initGlobal = llvm::cast<LLGlobalVariable>(initZ);
       initZ = irs->setGlobalVarInitializer(initGlobal, ir->getDefaultInit());
-      setLinkage(decl, initGlobal);
+      setLinkageAndVisibility(decl, initGlobal);
 
       // emit typeinfo
       if (!ir->suppressTypeInfo()) {
@@ -198,7 +198,7 @@ public:
       auto &initZ = ir->getInitSymbol();
       auto initGlobal = llvm::cast<LLGlobalVariable>(initZ);
       initZ = irs->setGlobalVarInitializer(initGlobal, ir->getDefaultInit());
-      setLinkage(decl, initGlobal);
+      setLinkageAndVisibility(decl, initGlobal);
 
       llvm::GlobalVariable *vtbl = ir->getVtblSymbol();
       defineGlobal(vtbl, ir->getVtblInit(), decl);

gen/llvmhelpers.cpp

@@ -1790,12 +1790,12 @@ llvm::GlobalVariable *declareGlobal(const Loc &loc, llvm::Module &module,
 }
 
 void defineGlobal(llvm::GlobalVariable *global, llvm::Constant *init,
-                  Dsymbol *symbolForLinkage) {
+                  Dsymbol *symbolForLinkageAndVisibility) {
   assert(global->isDeclaration() && "Global variable already defined");
   assert(init);
   global->setInitializer(init);
-  if (symbolForLinkage)
+  if (symbolForLinkageAndVisibility)
-    setLinkage(symbolForLinkage, global);
+    setLinkageAndVisibility(symbolForLinkageAndVisibility, global);
 }
 
 llvm::GlobalVariable *defineGlobal(const Loc &loc, llvm::Module &module,

gen/llvmhelpers.h

@@ -254,10 +254,10 @@ llvm::GlobalVariable *declareGlobal(const Loc &loc, llvm::Module &module,
                                     bool isThreadLocal = false);
 
 /// Defines an existing LLVM global, i.e., sets the initial value and finalizes
-/// its linkage.
+/// its linkage and visibility.
 /// Asserts that a global isn't defined multiple times this way.
 void defineGlobal(llvm::GlobalVariable *global, llvm::Constant *init,
-                  Dsymbol *symbolForLinkage);
+                  Dsymbol *symbolForLinkageAndVisibility);
 
 /// Declares (if not already declared) & defines an LLVM global.
 llvm::GlobalVariable *defineGlobal(const Loc &loc, llvm::Module &module,

gen/tollvm.cpp

@@ -16,6 +16,7 @@
 #include "dmd/id.h"
 #include "dmd/init.h"
 #include "dmd/module.h"
+#include "driver/cl_options.h"
 #include "gen/abi.h"
 #include "gen/arrays.h"
 #include "gen/classes.h"
@@ -243,8 +244,14 @@ void setLinkage(LinkageWithCOMDAT lwc, llvm::GlobalObject *obj) {
     obj->setComdat(gIR->module.getOrInsertComdat(obj->getName()));
 }
 
-void setLinkage(Dsymbol *sym, llvm::GlobalObject *obj) {
+void setLinkageAndVisibility(Dsymbol *sym, llvm::GlobalObject *obj) {
   setLinkage(DtoLinkage(sym), obj);
+  setVisibility(sym, obj);
+}
+
+void setVisibility(Dsymbol *sym, llvm::GlobalObject *obj) {
+  if (opts::defaultToHiddenVisibility && !sym->isExport())
+    obj->setVisibility(LLGlobalValue::HiddenVisibility);
 }
 
 ////////////////////////////////////////////////////////////////////////////////

gen/tollvm.h

@@ -71,7 +71,12 @@ LinkageWithCOMDAT DtoLinkage(Dsymbol *sym);
 
 bool supportsCOMDAT();
 void setLinkage(LinkageWithCOMDAT lwc, llvm::GlobalObject *obj);
-void setLinkage(Dsymbol *sym, llvm::GlobalObject *obj);
+// Sets the linkage of the specified IR global and possibly hides it, both based
+// on the specified D symbol.
+void setLinkageAndVisibility(Dsymbol *sym, llvm::GlobalObject *obj);
+// Hides the specified IR global if using `-fvisibility=hidden` and the
+// specified D symbol is not exported.
+void setVisibility(Dsymbol *sym, llvm::GlobalObject *obj);
 
 // some types
 LLIntegerType *DtoSize_t();

gen/typinf.cpp

@@ -666,6 +666,8 @@ void TypeInfoDeclaration_codegen(TypeInfoDeclaration *decl, IRState *p) {
   decl->accept(&v);
 
   setLinkage({TYPEINFO_LINKAGE_TYPE, supportsCOMDAT()}, gvar);
+  if (auto forStructType = forType->isTypeStruct())
+    setVisibility(forStructType->sym, gvar);
 }
 
 /* ========================================================================= */

tests/codegen/export_aggregate_symbols.d

@@ -0,0 +1,55 @@
+// Tests -fvisibility={default,hidden} for special symbols generated for
+// aggregates on non-Windows targets.
+
+// UNSUPPORTED: Windows
+
+// RUN: %ldc %s -shared -fvisibility=default -of=lib%t_default%so
+// RUN: nm -g lib%t_default%so | FileCheck -check-prefix=DEFAULT -check-prefix=BOTH %s
+
+// RUN: %ldc %s -shared -fvisibility=hidden -of=lib%t_hidden%so
+// RUN: nm -g lib%t_hidden%so | FileCheck -check-prefix=HIDDEN -check-prefix=BOTH %s
+
+
+// DEFAULT:    _D24export_aggregate_symbols8DefaultC11__interface24export_aggregate_symbols8DefaultI{{.*}}__vtblZ
+// HIDDEN-NOT: _D24export_aggregate_symbols8DefaultC11__interface24export_aggregate_symbols8DefaultI{{.*}}__vtblZ
+// DEFAULT:    _D24export_aggregate_symbols8DefaultC16__interfaceInfosZ
+// HIDDEN-NOT: _D24export_aggregate_symbols8DefaultC16__interfaceInfosZ
+// DEFAULT:    _D24export_aggregate_symbols8DefaultC6__initZ
+// HIDDEN-NOT: _D24export_aggregate_symbols8DefaultC6__initZ
+// DEFAULT:    _D24export_aggregate_symbols8DefaultC6__vtblZ
+// HIDDEN-NOT: _D24export_aggregate_symbols8DefaultC6__vtblZ
+// DEFAULT:    _D24export_aggregate_symbols8DefaultC7__ClassZ
+// HIDDEN-NOT: _D24export_aggregate_symbols8DefaultC7__ClassZ
+class DefaultC : DefaultI { void foo() {} }
+
+// DEFAULT:    _D24export_aggregate_symbols8DefaultI11__InterfaceZ
+// HIDDEN-NOT: _D24export_aggregate_symbols8DefaultI11__InterfaceZ
+interface DefaultI { void foo(); }
+
+// DEFAULT:    _D24export_aggregate_symbols8DefaultS6__initZ
+// HIDDEN-NOT: _D24export_aggregate_symbols8DefaultS6__initZ
+struct DefaultS {}
+
+
+
+// BOTH: _D24export_aggregate_symbols9ExportedC11__interface24export_aggregate_symbols9ExportedI{{.*}}__vtblZ
+// BOTH: _D24export_aggregate_symbols9ExportedC16__interfaceInfosZ
+// BOTH: _D24export_aggregate_symbols9ExportedC6__initZ
+// BOTH: _D24export_aggregate_symbols9ExportedC6__vtblZ
+// BOTH: _D24export_aggregate_symbols9ExportedC7__ClassZ
+export class ExportedC : ExportedI { void foo() {} }
+
+// BOTH: _D24export_aggregate_symbols9ExportedI11__InterfaceZ
+export interface ExportedI { void foo(); }
+
+// BOTH: _D24export_aggregate_symbols9ExportedS6__initZ
+export struct ExportedS {}
+
+
+
+// struct TypeInfos:
+
+// DEFAULT:    _D45TypeInfo_S24export_aggregate_symbols8DefaultS6__initZ
+// HIDDEN-NOT: _D45TypeInfo_S24export_aggregate_symbols8DefaultS6__initZ
+
+// BOTH: _D46TypeInfo_S24export_aggregate_symbols9ExportedS6__initZ

tests/codegen/export_marked_symbols1.d

@@ -3,10 +3,10 @@
 
 // UNSUPPORTED: Windows
 
-// RUN: ldc2 %s -betterC -shared -fvisibility=default -of=lib%t_default%so
+// RUN: %ldc %s -betterC -shared -fvisibility=default -of=lib%t_default%so
 // RUN: nm -g lib%t_default%so | FileCheck -check-prefix=DEFAULT %s
 
-// RUN: ldc2 %s -betterC -shared -fvisibility=hidden -of=lib%t_hidden%so
+// RUN: %ldc %s -betterC -shared -fvisibility=hidden -of=lib%t_hidden%so
 // RUN: nm -g lib%t_hidden%so | FileCheck -check-prefix=HIDDEN %s
 
 extern(C) export int test__exportedFun() { return 42; }

tests/codegen/export_marked_symbols2.d

@@ -3,9 +3,9 @@
 
 // UNSUPPORTED: Windows
 
-// RUN: ldc2 %S/inputs/export_marked_symbols_lib.d -shared -of=%t_lib%so
+// RUN: %ldc %S/inputs/export_marked_symbols_lib.d -shared -of=%t_lib%so
-// RUN: ldc2 %s -I%S/inputs -fvisibility=hidden -of=%t%exe %t_lib%so
+// RUN: %ldc %s -I%S/inputs -fvisibility=hidden -of=%t%exe %t_lib%so
-// RUN: ldc2 %s -I%S/inputs -fvisibility=hidden -of=%t%exe %t_lib%so -d-version=DECLARE_MANUALLY
+// RUN: %ldc %s -I%S/inputs -fvisibility=hidden -of=%t%exe %t_lib%so -d-version=DECLARE_MANUALLY
 
 version (DECLARE_MANUALLY)
 {

tests/codegen/export_marked_symbols_thin_lto.d

@@ -3,8 +3,8 @@
 
 // REQUIRES: LTO
 
-// RUN: ldc2 %S/inputs/export_marked_symbols_lib.d -c -fvisibility=hidden -flto=thin -of=%t_lib%obj
+// RUN: %ldc %S/inputs/export_marked_symbols_lib.d -c -fvisibility=hidden -flto=thin -of=%t_lib%obj
-// RUN: ldc2 %s -I%S/inputs -flto=thin -of=%t%exe %t_lib%obj
+// RUN: %ldc %s -I%S/inputs -flto=thin -of=%t%exe %t_lib%obj
 
 import export_marked_symbols_lib;