Add /Zc:DllexportInlines option to clang-cl

Summary: This CL adds /Zc:DllexportInlines flag to clang-cl. When Zc:DllexportInlines- is specified, inline class member function is not exported if the function does not have local static variables. By not exporting inline function, code for those functions are not generated and that reduces both compile time and obj size. Also this flag does not import inline functions from dllimported class if the function does not have local static variables. On my 24C48T windows10 machine, build performance of chrome target in chromium repository is like below. These stats are come with 'target_cpu="x86" enable_nacl = false is_component_build=true dcheck_always_on=true` build config and applied * https://chromium-review.googlesource.com/c/chromium/src/+/1212379 * https://chromium-review.googlesource.com/c/v8/v8/+/1186017 Below stats were taken with this patch applied on https://github.com/llvm-project/llvm-project-20170507/commit/a05115cd4c57ff76b0f529e38118765b58ed7f2e | config | build time | speedup | build dir size | | with patch, PCH on, debug | 1h10m0s | x1.13 | 35.6GB | | without patch, PCH on, debug | 1h19m17s | | 49.0GB | | with patch, PCH off, debug | 1h15m45s | x1.16 | 33.7GB | | without patch, PCH off, debug | 1h28m10s | | 52.3GB | | with patch, PCH on, release | 1h13m13s | x1.22 | 26.2GB | | without patch, PCH on, release | 1h29m57s | | 37.5GB | | with patch, PCH off, release | 1h23m38s | x1.32 | 23.7GB | | without patch, PCH off, release | 1h50m50s | | 38.7GB | This patch reduced obj size and the number of exported symbols largely, that improved link time too. e.g. link time stats of blink_core.dll become like below | | cold disk cache | warm disk cache | | with patch, PCH on, debug | 71s | 30s | | without patch, PCH on, debug | 111s | 48s | This patch's implementation is based on Nico Weber's patch. I modified to support static local variable, added tests and took stats. Bug: https://bugs.llvm.org/show_bug.cgi?id=33628 Reviewers: hans, thakis, rnk, javed.absar Reviewed By: hans Subscribers: kristof.beyls, smeenai, dschuff, probinson, cfe-commits, eraman Differential Revision: https://reviews.llvm.org/D51340 llvm-svn: 346069
llvm · Nov 3, 2018 · 302c643 · 302c643
1 parent 4ec5d67
commit 302c643
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diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
@@ -2683,6 +2683,17 @@ def DLLExport : InheritableAttr, TargetSpecificAttr<TargetWindows> {
   let Documentation = [DLLExportDocs];
 }
 
+def DLLExportStaticLocal : InheritableAttr, TargetSpecificAttr<TargetWindows> {
+  // This attribute is used internally only when -fno-dllexport-inlines is
+  // passed. This attribute is added to inline function of class having
+  // dllexport attribute. And if the function has static local variables, this
+  // attribute is used to whether the variables are exported or not. Also if
+  // function has local static variables, the function is dllexported too.
+  let Spellings = [];
+  let Subjects = SubjectList<[Function]>;
+  let Documentation = [Undocumented];
+}
+
 def DLLImport : InheritableAttr, TargetSpecificAttr<TargetWindows> {
   let Spellings = [Declspec<"dllimport">, GCC<"dllimport">];
   let Subjects = SubjectList<[Function, Var, CXXRecord, ObjCInterface]>;
@@ -2699,6 +2710,16 @@ public:
   }];
 }
 
+def DLLImportStaticLocal : InheritableAttr, TargetSpecificAttr<TargetWindows> {
+  // This attribute is used internally only when -fno-dllexport-inlines is
+  // passed. This attribute is added to inline function of class having
+  // dllimport attribute. And if the function has static local variables, this
+  // attribute is used to whether the variables are imported or not.
+  let Spellings = [];
+  let Subjects = SubjectList<[Function]>;
+  let Documentation = [Undocumented];
+}
+
 def SelectAny : InheritableAttr {
   let Spellings = [Declspec<"selectany">, GCC<"selectany">];
   let Documentation = [SelectAnyDocs];

diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
@@ -138,6 +138,7 @@ LANGOPT(NoBuiltin         , 1, 0, "disable builtin functions")
 LANGOPT(NoMathBuiltin     , 1, 0, "disable math builtin functions")
 LANGOPT(GNUAsm            , 1, 1, "GNU-style inline assembly")
 LANGOPT(CoroutinesTS      , 1, 0, "C++ coroutines TS")
+LANGOPT(DllExportInlines  , 1, 1, "dllexported classes dllexport inline methods")
 LANGOPT(RelaxedTemplateTemplateArgs, 1, 0, "C++17 relaxed matching of template template arguments")
 
 LANGOPT(DoubleSquareBracketAttributes, 1, 0, "'[[]]' attributes extension for all language standard modes")

diff --git a/clang/include/clang/Driver/CC1Options.td b/clang/include/clang/Driver/CC1Options.td
@@ -363,6 +363,7 @@ def fno_debug_pass_manager : Flag<["-"], "fno-debug-pass-manager">,
 def msign_return_address_key_EQ : Joined<["-"], "msign-return-address-key=">,
     Values<"a_key,b_key">;
 def mbranch_target_enforce : Flag<["-"], "mbranch-target-enforce">;
+def fno_dllexport_inlines : Flag<["-"], "fno-dllexport-inlines">;
 
 //===----------------------------------------------------------------------===//
 // Dependency Output Options

diff --git a/clang/include/clang/Driver/CLCompatOptions.td b/clang/include/clang/Driver/CLCompatOptions.td
@@ -333,6 +333,8 @@ def _SLASH_Yu : CLJoined<"Yu">,
   MetaVarName<"<filename>">;
 def _SLASH_Y_ : CLFlag<"Y-">,
   HelpText<"Disable precompiled headers, overrides /Yc and /Yu">;
+def _SLASH_Zc_dllexportInlines : CLFlag<"Zc:dllexportInlines">;
+def _SLASH_Zc_dllexportInlines_ : CLFlag<"Zc:dllexportInlines-">;
 def _SLASH_Fp : CLJoined<"Fp">,
   HelpText<"Set pch filename (with /Yc and /Yu)">, MetaVarName<"<filename>">;
 

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -5504,6 +5504,11 @@ void Clang::AddClangCLArgs(const ArgList &Args, types::ID InputType,
   if (VolatileOptionID == options::OPT__SLASH_volatile_ms)
     CmdArgs.push_back("-fms-volatile");
 
+ if (Args.hasFlag(options::OPT__SLASH_Zc_dllexportInlines_,
+                  options::OPT__SLASH_Zc_dllexportInlines,
+                  false))
+    CmdArgs.push_back("-fno-dllexport-inlines");
+
   Arg *MostGeneralArg = Args.getLastArg(options::OPT__SLASH_vmg);
   Arg *BestCaseArg = Args.getLastArg(options::OPT__SLASH_vmb);
   if (MostGeneralArg && BestCaseArg)

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2179,6 +2179,9 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
     }
   }
 
+  if (Args.hasArg(OPT_fno_dllexport_inlines))
+    Opts.DllExportInlines = false;
+
   if (const Arg *A = Args.getLastArg(OPT_fcf_protection_EQ)) {
     StringRef Name = A->getValue();
     if (Name == "full" || Name == "branch") {

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
@@ -11930,6 +11930,14 @@ void Sema::CheckStaticLocalForDllExport(VarDecl *VD) {
   assert(VD->isStaticLocal());
 
   auto *FD = dyn_cast_or_null<FunctionDecl>(VD->getParentFunctionOrMethod());
+
+  // Find outermost function when VD is in lambda function.
+  while (FD && !getDLLAttr(FD) &&
+         !FD->hasAttr<DLLExportStaticLocalAttr>() &&
+         !FD->hasAttr<DLLImportStaticLocalAttr>()) {
+    FD = dyn_cast_or_null<FunctionDecl>(FD->getParentFunctionOrMethod());
+  }
+
   if (!FD)
     return;
 
@@ -11938,6 +11946,24 @@ void Sema::CheckStaticLocalForDllExport(VarDecl *VD) {
     auto *NewAttr = cast<InheritableAttr>(A->clone(getASTContext()));
     NewAttr->setInherited(true);
     VD->addAttr(NewAttr);
+  } else if (Attr *A = FD->getAttr<DLLExportStaticLocalAttr>()) {
+    auto *NewAttr = ::new (getASTContext()) DLLExportAttr(A->getRange(),
+                                                          getASTContext(),
+                                                          A->getSpellingListIndex());
+    NewAttr->setInherited(true);
+    VD->addAttr(NewAttr);
+
+    // Export this function to enforce exporting this static variable even
+    // if it is not used in this compilation unit.
+    if (!FD->hasAttr<DLLExportAttr>())
+      FD->addAttr(NewAttr);
+
+  } else if (Attr *A = FD->getAttr<DLLImportStaticLocalAttr>()) {
+    auto *NewAttr = ::new (getASTContext()) DLLImportAttr(A->getRange(),
+                                                          getASTContext(),
+                                                          A->getSpellingListIndex());
+    NewAttr->setInherited(true);
+    VD->addAttr(NewAttr);
   }
 }
 

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -5707,8 +5707,28 @@ void Sema::checkClassLevelDLLAttribute(CXXRecordDecl *Class) {
       continue;
 
     if (!getDLLAttr(Member)) {
-      auto *NewAttr =
-          cast<InheritableAttr>(ClassAttr->clone(getASTContext()));
+      InheritableAttr *NewAttr = nullptr;
+
+      // Do not export/import inline function when -fno-dllexport-inlines is
+      // passed. But add attribute for later local static var check.
+      if (!getLangOpts().DllExportInlines && MD && MD->isInlined() &&
+          TSK != TSK_ExplicitInstantiationDeclaration &&
+          TSK != TSK_ExplicitInstantiationDefinition) {
+        if (ClassExported) {
+          NewAttr = ::new (getASTContext())
+            DLLExportStaticLocalAttr(ClassAttr->getRange(),
+                                     getASTContext(),
+                                     ClassAttr->getSpellingListIndex());
+        } else {
+          NewAttr = ::new (getASTContext())
+            DLLImportStaticLocalAttr(ClassAttr->getRange(),
+                                     getASTContext(),
+                                     ClassAttr->getSpellingListIndex());
+        }
+      } else {
+        NewAttr = cast<InheritableAttr>(ClassAttr->clone(getASTContext()));
+      }
+
       NewAttr->setInherited(true);
       Member->addAttr(NewAttr);
 

diff --git a/clang/test/CodeGenCXX/dllexport-no-dllexport-inlines.cpp b/clang/test/CodeGenCXX/dllexport-no-dllexport-inlines.cpp
@@ -0,0 +1,133 @@
+// RUN: %clang_cc1 %s -fms-extensions -triple x86_64-windows-msvc       \
+// RUN:     -disable-llvm-passes                                        \
+// RUN:     -fno-dllexport-inlines -emit-llvm -O1 -o - |                \
+// RUN:     FileCheck --check-prefix=CHECK --check-prefix=NOEXPORTINLINE %s
+
+// RUN: %clang_cc1 %s -fms-extensions -triple x86_64-windows-msvc       \
+// RUN:     -disable-llvm-passes                                        \
+// RUN:     -emit-llvm -O1 -o - |                                       \
+// RUN:     FileCheck --check-prefix=CHECK  --check-prefix=EXPORTINLINE %s
+
+
+struct __declspec(dllexport) ExportedClass {
+
+  // NOEXPORTINLINE-DAG: define linkonce_odr dso_local void @"?InclassDefFunc@ExportedClass@@
+  // EXPORTINLINE-DAG: define weak_odr dso_local dllexport void @"?InclassDefFunc@ExportedClass@@
+  void InclassDefFunc() {}
+
+  // CHECK-DAG: define weak_odr dso_local dllexport i32 @"?InclassDefFuncWithStaticVariable@ExportedClass@@QEAAHXZ"
+  int InclassDefFuncWithStaticVariable() {
+    // CHECK-DAG: @"?static_variable@?1??InclassDefFuncWithStaticVariable@ExportedClass@@QEAAHXZ@4HA" = weak_odr dso_local dllexport global i32 0, comdat, align 4
+    static int static_variable = 0;
+    ++static_variable;
+    return static_variable;
+  }
+
+  // CHECK-DAG: define weak_odr dso_local dllexport i32 @"?InclassDefFunctWithLambdaStaticVariable@ExportedClass@@QEAAHXZ"
+  int InclassDefFunctWithLambdaStaticVariable() {
+    // CHECK-DAG: @"?static_x@?2???R<lambda_1>@?0??InclassDefFunctWithLambdaStaticVariable@ExportedClass@@QEAAHXZ@QEBA?A?<auto>@@XZ@4HA" = weak_odr dso_local dllexport global i32 0, comdat, align 4
+    return ([]() { static int static_x; return ++static_x; })();
+  }
+
+  // NOEXPORTINLINE-DAG: define linkonce_odr dso_local void @"?InlineOutclassDefFunc@ExportedClass@@QEAAXXZ
+  // EXPORTINLINE-DAG: define weak_odr dso_local dllexport void @"?InlineOutclassDefFunc@ExportedClass@@QEAAXXZ
+  inline void InlineOutclassDefFunc();
+
+  // CHECK-DAG: define weak_odr dso_local dllexport i32 @"?InlineOutclassDefFuncWithStaticVariable@ExportedClass@@QEAAHXZ"
+  inline int InlineOutclassDefFuncWithStaticVariable();
+
+  // CHECK-DAG: define dso_local dllexport void @"?OutoflineDefFunc@ExportedClass@@QEAAXXZ"
+  void OutoflineDefFunc();
+};
+
+void ExportedClass::OutoflineDefFunc() {}
+
+inline void ExportedClass::InlineOutclassDefFunc() {}
+
+inline int ExportedClass::InlineOutclassDefFuncWithStaticVariable() {
+  static int static_variable = 0;
+  return ++static_variable;
+}
+
+void ExportedClassUser() {
+  ExportedClass a;
+  a.InclassDefFunc();
+  a.InlineOutclassDefFunc();
+}
+
+template<typename T>
+struct __declspec(dllexport) TemplateExportedClass {
+  void InclassDefFunc() {}
+
+  int InclassDefFuncWithStaticVariable() {
+    static int static_x = 0;
+    return ++static_x;
+  }
+};
+
+class A11{};
+class B22{};
+
+// CHECK-DAG: define weak_odr dso_local dllexport void @"?InclassDefFunc@?$TemplateExportedClass@VA11@@@@QEAAXXZ"
+// CHECK-DAG: define weak_odr dso_local dllexport i32 @"?InclassDefFuncWithStaticVariable@?$TemplateExportedClass@VA11@@@@QEAAHXZ"
+// CHECK-DAG: @"?static_x@?2??InclassDefFuncWithStaticVariable@?$TemplateExportedClass@VA11@@@@QEAAHXZ@4HA" = weak_odr dso_local dllexport global i32 0, comdat, align 4
+template class TemplateExportedClass<A11>;
+
+// NOEXPORTINLINE-DAG: define linkonce_odr dso_local void @"?InclassDefFunc@?$TemplateExportedClass@VB22@@@@QEAAXXZ"
+// EXPORTINLINE-DAG: define weak_odr dso_local dllexport void @"?InclassDefFunc@?$TemplateExportedClass@VB22@@@@QEAAXXZ
+// CHECK-DAG: define weak_odr dso_local dllexport i32 @"?InclassDefFuncWithStaticVariable@?$TemplateExportedClass@VB22@@@@QEAAHXZ"
+// CHECK-DAG: @"?static_x@?2??InclassDefFuncWithStaticVariable@?$TemplateExportedClass@VB22@@@@QEAAHXZ@4HA" = weak_odr dso_local dllexport global i32 0, comdat, align 4
+TemplateExportedClass<B22> b22;
+
+void TemplateExportedClassUser() {
+  b22.InclassDefFunc();
+  b22.InclassDefFuncWithStaticVariable();
+}
+
+
+template<typename T>
+struct TemplateNoAttributeClass {
+  void InclassDefFunc() {}
+  int InclassDefFuncWithStaticLocal() {
+    static int static_x;
+    return ++static_x;
+  }
+};
+
+// CHECK-DAG: define weak_odr dso_local dllexport void @"?InclassDefFunc@?$TemplateNoAttributeClass@VA11@@@@QEAAXXZ"
+// CHECK-DAG: define weak_odr dso_local dllexport i32 @"?InclassDefFuncWithStaticLocal@?$TemplateNoAttributeClass@VA11
+// CHECK-DAG: @"?static_x@?2??InclassDefFuncWithStaticLocal@?$TemplateNoAttributeClass@VA11@@@@QEAAHXZ@4HA" = weak_odr dso_local dllexport global i32 0, comdat, align 4
+template class __declspec(dllexport) TemplateNoAttributeClass<A11>;
+
+// CHECK-DAG: define available_externally dllimport void @"?InclassDefFunc@?$TemplateNoAttributeClass@VB22@@@@QEAAXXZ"
+// CHECK-DAG: define available_externally dllimport i32 @"?InclassDefFuncWithStaticLocal@?$TemplateNoAttributeClass@VB22@@@@QEAAHXZ"
+// CHECK-DAG: @"?static_x@?2??InclassDefFuncWithStaticLocal@?$TemplateNoAttributeClass@VB22@@@@QEAAHXZ@4HA" = available_externally dllimport global i32 0, align 4
+extern template class __declspec(dllimport) TemplateNoAttributeClass<B22>;
+
+void TemplateNoAttributeClassUser() {
+  TemplateNoAttributeClass<B22> b22;
+  b22.InclassDefFunc();
+  b22.InclassDefFuncWithStaticLocal();
+}
+
+struct __declspec(dllimport) ImportedClass {
+  // NOEXPORTINLINE-DAG: define linkonce_odr dso_local void @"?InClassDefFunc@ImportedClass@@QEAAXXZ"
+  // EXPORTINLINE-DAG: define available_externally dllimport void @"?InClassDefFunc@ImportedClass@@QEAAXXZ"
+  void InClassDefFunc() {}
+
+  // EXPORTINLINE-DAG: define available_externally dllimport i32 @"?InClassDefFuncWithStaticVariable@ImportedClass@@QEAAHXZ"
+  // NOEXPORTINLINE-DAG: define linkonce_odr dso_local i32 @"?InClassDefFuncWithStaticVariable@ImportedClass@@QEAAHXZ"
+  int InClassDefFuncWithStaticVariable() {
+    // CHECK-DAG: @"?static_variable@?1??InClassDefFuncWithStaticVariable@ImportedClass@@QEAAHXZ@4HA" = available_externally dllimport global i32 0, align 4
+    static int static_variable = 0;
+    ++static_variable;
+    return static_variable;
+  }
+};
+
+int InClassDefFuncUser() {
+  // This is necessary for declare statement of ImportedClass::InClassDefFunc().
+  ImportedClass c;
+  c.InClassDefFunc();
+  return c.InClassDefFuncWithStaticVariable();
+}
diff --git a/clang/test/Driver/cl-options.c b/clang/test/Driver/cl-options.c
@@ -490,6 +490,11 @@
 // RUN: %clang_cl /Zc:threadSafeInit /c -### -- %s 2>&1 | FileCheck -check-prefix=ThreadSafeStatics %s
 // ThreadSafeStatics-NOT: "-fno-threadsafe-statics"
 
+// RUN: %clang_cl /Zc:dllexportInlines- /c -### -- %s 2>&1 | FileCheck -check-prefix=NoDllExportInlines %s
+// NoDllExportInlines: "-fno-dllexport-inlines"
+// RUN: %clang_cl /Zc:dllexportInlines /c -### -- %s 2>&1 | FileCheck -check-prefix=DllExportInlines %s
+// DllExportInlines-NOT: "-fno-dllexport-inlines"
+
 // RUN: %clang_cl /Zi /c -### -- %s 2>&1 | FileCheck -check-prefix=Zi %s
 // Zi: "-gcodeview"
 // Zi: "-debug-info-kind=limited"