Author: Shoaib Meenai Date: 2024-08-26T13:11:05-07:00 New Revision: 7945435f46c4b0a9fd08c6d76eee8ea8f5e37bca
URL: https://github.com/llvm/llvm-project/commit/7945435f46c4b0a9fd08c6d76eee8ea8f5e37bca DIFF: https://github.com/llvm/llvm-project/commit/7945435f46c4b0a9fd08c6d76eee8ea8f5e37bca.diff LOG: [clang] Add support for omitting only global destructors (#104899) For mobile applications, it's common for global destructors to never be called (because the applications have their own lifecycle independent of the standard C runtime), but threads are created and destroyed as normal and so thread-local destructors are still called. -fno-static-c++-destructors omits unnecessary global destructors, which is useful for code size, but it also omits thread-local destructors, which is unsuitable. Add a ternary `-fc++-static-destructors={all,none,thread-local}` option instead to allow omitting only global destructors. Added: clang/test/Driver/cxx-static-destructors.cpp Modified: clang/docs/ReleaseNotes.rst clang/include/clang/Basic/LangOptions.def clang/include/clang/Basic/LangOptions.h clang/include/clang/Driver/Options.td clang/lib/AST/Decl.cpp clang/lib/Driver/ToolChains/Clang.cpp clang/test/CodeGenCXX/always_destroy.cpp clang/test/CodeGenCXX/attr-no-destroy-d54344.cpp clang/test/SemaCXX/no_destroy.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 7a9e7f0b4eba69..0a31953ab87005 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -173,6 +173,13 @@ Non-comprehensive list of changes in this release New Compiler Flags ------------------ +- The ``-fc++-static-destructors={all,thread-local,none}`` flag was + added to control which C++ variables have static destructors + registered: all (the default) does so for all variables, thread-local + only for thread-local variables, and none (which corresponds to the + existing ``-fno-c++-static-destructors`` flag) skips all static + destructors registration. + Deprecated Compiler Flags ------------------------- diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def index 956d9a2d2434c4..fd3346d29f26a3 100644 --- a/clang/include/clang/Basic/LangOptions.def +++ b/clang/include/clang/Basic/LangOptions.def @@ -464,7 +464,9 @@ LANGOPT(FixedPoint, 1, 0, "fixed point types") LANGOPT(PaddingOnUnsignedFixedPoint, 1, 0, "unsigned fixed point types having one extra padding bit") -LANGOPT(RegisterStaticDestructors, 1, 1, "Register C++ static destructors") +ENUM_LANGOPT(RegisterStaticDestructors, RegisterStaticDestructorsKind, 2, + RegisterStaticDestructorsKind::All, + "Register C++ static destructors") LANGOPT(RegCall4, 1, 0, "Set __regcall4 as a default calling convention to respect __regcall ABI v.4") diff --git a/clang/include/clang/Basic/LangOptions.h b/clang/include/clang/Basic/LangOptions.h index 1c80ee89837cb3..51a34686ad7e1d 100644 --- a/clang/include/clang/Basic/LangOptions.h +++ b/clang/include/clang/Basic/LangOptions.h @@ -458,6 +458,16 @@ class LangOptionsBase { CX_None }; + /// Controls which variables have static destructors registered. + enum class RegisterStaticDestructorsKind { + /// Register static destructors for all variables. + All, + /// Register static destructors only for thread-local variables. + ThreadLocal, + /// Don't register static destructors for any variables. + None, + }; + // Define simple language options (with no accessors). #define LANGOPT(Name, Bits, Default, Description) unsigned Name : Bits; #define ENUM_LANGOPT(Name, Type, Bits, Default, Description) diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td index 1b9b3f2c6600a3..83cf753e824845 100644 --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -2302,11 +2302,18 @@ defm fixed_point : BoolFOption<"fixed-point", PosFlag<SetTrue, [], [ClangOption, CC1Option], "Enable">, NegFlag<SetFalse, [], [ClangOption], "Disable">, BothFlags<[], [ClangOption], " fixed point types">>; -defm cxx_static_destructors : BoolFOption<"c++-static-destructors", - LangOpts<"RegisterStaticDestructors">, DefaultTrue, - NegFlag<SetFalse, [], [ClangOption, CC1Option], - "Disable C++ static destructor registration">, - PosFlag<SetTrue>>; +def cxx_static_destructors_EQ : Joined<["-"], "fc++-static-destructors=">, Group<f_Group>, + HelpText<"Controls which variables C++ static destructors are registered for">, + Values<"all,thread-local,none">, + NormalizedValues<["All", "ThreadLocal", "None"]>, + NormalizedValuesScope<"LangOptions::RegisterStaticDestructorsKind">, + MarshallingInfoEnum<LangOpts<"RegisterStaticDestructors">, "All">, + Visibility<[ClangOption, CC1Option]>; +def cxx_static_destructors : Flag<["-"], "fc++-static-destructors">, Group<f_Group>, + Alias<cxx_static_destructors_EQ>, AliasArgs<["all"]>; +def no_cxx_static_destructors : Flag<["-"], "fno-c++-static-destructors">, Group<f_Group>, + Alias<cxx_static_destructors_EQ>, AliasArgs<["none"]>, + HelpText<"Disable C++ static destructor registration">; def fsymbol_partition_EQ : Joined<["-"], "fsymbol-partition=">, Group<f_Group>, Visibility<[ClangOption, CC1Option]>, MarshallingInfoString<CodeGenOpts<"SymbolPartition">>; diff --git a/clang/lib/AST/Decl.cpp b/clang/lib/AST/Decl.cpp index 90caf81757ac96..1a07125815832e 100644 --- a/clang/lib/AST/Decl.cpp +++ b/clang/lib/AST/Decl.cpp @@ -2799,9 +2799,17 @@ bool VarDecl::isKnownToBeDefined() const { } bool VarDecl::isNoDestroy(const ASTContext &Ctx) const { - return hasGlobalStorage() && (hasAttr<NoDestroyAttr>() || - (!Ctx.getLangOpts().RegisterStaticDestructors && - !hasAttr<AlwaysDestroyAttr>())); + if (!hasGlobalStorage()) + return false; + if (hasAttr<NoDestroyAttr>()) + return true; + if (hasAttr<AlwaysDestroyAttr>()) + return false; + + using RSDKind = LangOptions::RegisterStaticDestructorsKind; + RSDKind K = Ctx.getLangOpts().getRegisterStaticDestructors(); + return K == RSDKind::None || + (K == RSDKind::ThreadLocal && getTLSKind() == TLS_None); } QualType::DestructionKind diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp index 9f1d57f43b6565..df86941950e46e 100644 --- a/clang/lib/Driver/ToolChains/Clang.cpp +++ b/clang/lib/Driver/ToolChains/Clang.cpp @@ -7972,8 +7972,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA, options::OPT_fno_keep_persistent_storage_variables); Args.addOptInFlag(CmdArgs, options::OPT_fcomplete_member_pointers, options::OPT_fno_complete_member_pointers); - Args.addOptOutFlag(CmdArgs, options::OPT_fcxx_static_destructors, - options::OPT_fno_cxx_static_destructors); + if (Arg *A = Args.getLastArg(options::OPT_cxx_static_destructors_EQ)) + A->render(Args, CmdArgs); addMachineOutlinerArgs(D, Args, CmdArgs, Triple, /*IsLTO=*/false); diff --git a/clang/test/CodeGenCXX/always_destroy.cpp b/clang/test/CodeGenCXX/always_destroy.cpp index e84c4cf02c52f5..ca8a8e0cabacb3 100644 --- a/clang/test/CodeGenCXX/always_destroy.cpp +++ b/clang/test/CodeGenCXX/always_destroy.cpp @@ -1,4 +1,7 @@ -// RUN: %clang_cc1 %s -fno-c++-static-destructors -emit-llvm -triple x86_64-apple-macosx10.13.0 -o - | FileCheck %s +// RUN: %clang_cc1 %s -fc++-static-destructors=none -emit-llvm -triple x86_64-apple-macosx10.13.0 -o - | \ +// RUN: FileCheck --check-prefixes=CHECK,NO-DTORS %s +// RUN: %clang_cc1 %s -fc++-static-destructors=thread-local -emit-llvm -triple x86_64-apple-macosx10.13.0 -o - | \ +// RUN: FileCheck --check-prefixes=CHECK,THREAD-LOCAL-DTORS %s struct NonTrivial { ~NonTrivial(); @@ -6,7 +9,8 @@ struct NonTrivial { // CHECK-NOT: __cxa_atexit{{.*}}_ZN10NonTrivialD1Ev NonTrivial nt1; -// CHECK-NOT: _tlv_atexit{{.*}}_ZN10NonTrivialD1Ev +// NO-DTORS-NOT: _tlv_atexit{{.*}}_ZN10NonTrivialD1Ev +// THREAD-LOCAL-DTORS: _tlv_atexit{{.*}}_ZN10NonTrivialD1Ev thread_local NonTrivial nt2; struct NonTrivial2 { diff --git a/clang/test/CodeGenCXX/attr-no-destroy-d54344.cpp b/clang/test/CodeGenCXX/attr-no-destroy-d54344.cpp index b03791e5135df5..053043adb61c17 100644 --- a/clang/test/CodeGenCXX/attr-no-destroy-d54344.cpp +++ b/clang/test/CodeGenCXX/attr-no-destroy-d54344.cpp @@ -1,6 +1,7 @@ // RUN: %clang_cc1 -std=c++2a -emit-llvm -O0 -triple x86_64-unknown-linux-gnu -DNOATTR %s -o - | FileCheck %s // RUN: %clang_cc1 -std=c++2a -emit-llvm -O0 -triple x86_64-unknown-linux-gnu %s -o - | FileCheck %s --check-prefix=CHECK-ATTR -// RUN: %clang_cc1 -std=c++2a -emit-llvm -O0 -triple x86_64-unknown-linux-gnu -DNOATTR -fno-c++-static-destructors %s -o - | FileCheck %s --check-prefix=CHECK-FLAG +// RUN: %clang_cc1 -std=c++2a -emit-llvm -O0 -triple x86_64-unknown-linux-gnu -DNOATTR -fc++-static-destructors=none %s -o - | FileCheck %s --check-prefix=CHECK-FLAG +// RUN: %clang_cc1 -std=c++2a -emit-llvm -O0 -triple x86_64-unknown-linux-gnu -DNOATTR -fc++-static-destructors=thread-local %s -o - | FileCheck %s --check-prefix=CHECK-FLAG // Regression test for D54344. Class with no user-defined destructor // that has an inherited member that has a non-trivial destructor diff --git a/clang/test/Driver/cxx-static-destructors.cpp b/clang/test/Driver/cxx-static-destructors.cpp new file mode 100644 index 00000000000000..a12a292a387bda --- /dev/null +++ b/clang/test/Driver/cxx-static-destructors.cpp @@ -0,0 +1,11 @@ +// RUN: %clang -### -c -fc++-static-destructors=all %s 2>&1 | FileCheck --check-prefix ALL %s +// RUN: %clang -### -c -fc++-static-destructors %s 2>&1 | FileCheck --check-prefix ALL %s +// RUN: %clang -### -c -fno-c++-static-destructors -fc++-static-destructors %s 2>&1 | FileCheck --check-prefix ALL %s +// RUN: %clang -### -c -fc++-static-destructors=none %s 2>&1 | FileCheck --check-prefix NONE %s +// RUN: %clang -### -c -fno-c++-static-destructors %s 2>&1 | FileCheck --check-prefix NONE %s +// RUN: %clang -### -c -fc++-static-destructors -fno-c++-static-destructors %s 2>&1 | FileCheck --check-prefix NONE %s +// RUN: %clang -### -c -fc++-static-destructors=thread-local %s 2>&1 | FileCheck --check-prefix THREAD-LOCAL %s + +// ALL: -fc++-static-destructors=all +// NONE: -fc++-static-destructors=none +// THREAD-LOCAL: -fc++-static-destructors=thread-local diff --git a/clang/test/SemaCXX/no_destroy.cpp b/clang/test/SemaCXX/no_destroy.cpp index 5872bcf4b439e2..d39bcaeff860a1 100644 --- a/clang/test/SemaCXX/no_destroy.cpp +++ b/clang/test/SemaCXX/no_destroy.cpp @@ -1,31 +1,21 @@ -// RUN: %clang_cc1 -DNO_DTORS -DNO_EXCEPTIONS -fno-c++-static-destructors -verify %s -// RUN: %clang_cc1 -DNO_EXCEPTIONS -verify %s -// RUN: %clang_cc1 -DNO_DTORS -fexceptions -fno-c++-static-destructors -verify %s -// RUN: %clang_cc1 -fexceptions -verify %s +// RUN: %clang_cc1 -fc++-static-destructors=none -verify %s +// RUN: %clang_cc1 -fc++-static-destructors=thread-local -verify=expected,thread-local-dtors %s +// RUN: %clang_cc1 -verify=expected,thread-local-dtors,all-dtors %s +// RUN: %clang_cc1 -fexceptions -fc++-static-destructors=none -verify %s +// RUN: %clang_cc1 -fexceptions -fc++-static-destructors=thread-local -verify=expected,thread-local-dtors %s +// RUN: %clang_cc1 -fexceptions -verify=expected,thread-local-dtors,all-dtors %s struct SecretDestructor { -#ifndef NO_DTORS - // expected-note@+2 4 {{private}} -#endif private: ~SecretDestructor(); // expected-note + {{private}} }; -SecretDestructor sd1; -thread_local SecretDestructor sd2; +SecretDestructor sd1; // all-dtors-error{{private}} +thread_local SecretDestructor sd2; // thread-local-dtors-error{{private}} void locals() { - static SecretDestructor sd3; - thread_local SecretDestructor sd4; + static SecretDestructor sd3; // all-dtors-error{{private}} + thread_local SecretDestructor sd4; // thread-local-dtors-error{{private}} } -#ifndef NO_DTORS -// SecretDestructor sd1; // expected-error@-8 {{private}} -// thread_local SecretDestructor sd2; // expected-error@-8 {{private}} -// void locals() { -// static SecretDestructor sd3; // expected-error@-8 {{private}} -// thread_local SecretDestructor sd4; // expected-error@-8 {{private}} -// } -#endif - [[clang::always_destroy]] SecretDestructor sd6; // expected-error{{private}} [[clang::always_destroy]] thread_local SecretDestructor sd7; // expected-error{{private}} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
