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[clang] Add support for omitting only global destructors #104899

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Merged
merged 2 commits into from
Aug 26, 2024
Merged

[clang] Add support for omitting only global destructors #104899

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e0a1a4d
[clang] Add support for omitting only global destructors
smeenai Aug 20, 2024
76d4eb2
Address comments and add release note
smeenai Aug 20, 2024
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4 changes: 3 additions & 1 deletion clang/include/clang/Basic/LangOptions.def
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Original file line number Diff line number Diff line change
Expand Up @@ -465,7 +465,9 @@ 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")

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10 changes: 10 additions & 0 deletions clang/include/clang/Basic/LangOptions.h
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Expand Up @@ -441,6 +441,16 @@ 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)
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17 changes: 12 additions & 5 deletions clang/include/clang/Driver/Options.td
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Expand Up @@ -2300,11 +2300,18 @@ 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">>;
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14 changes: 11 additions & 3 deletions clang/lib/AST/Decl.cpp
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Expand Up @@ -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
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5 changes: 3 additions & 2 deletions clang/lib/Driver/ToolChains/Clang.cpp
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Expand Up @@ -7967,8 +7967,9 @@ 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))
CmdArgs.push_back(
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A->render(Args, CmdArgs);

Args.MakeArgString(Twine("-fc++-static-destructors=") + A->getValue()));

addMachineOutlinerArgs(D, Args, CmdArgs, Triple, /*IsLTO=*/false);

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8 changes: 6 additions & 2 deletions clang/test/CodeGenCXX/always_destroy.cpp
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@@ -1,12 +1,16 @@
// 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();
};

// 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 {
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3 changes: 2 additions & 1 deletion clang/test/CodeGenCXX/attr-no-destroy-d54344.cpp
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@@ -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
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9 changes: 9 additions & 0 deletions clang/test/Driver/cxx-static-destructors.cpp
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@@ -0,0 +1,9 @@
// 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 -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=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
30 changes: 10 additions & 20 deletions clang/test/SemaCXX/no_destroy.cpp
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@@ -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}}

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