New Compiler Flags
------------------
+The sized deallocation feature of C++14 is now controlled by the
+``-fsized-deallocation`` flag. This feature relies on library support that
+isn't yet widely deployed, so the user must supply an extra flag to get the
+extra functionality.
+
The option ....
/// allocation function. [...]
bool isReplaceableGlobalAllocationFunction() const;
- /// \brief Determine whether this function is a sized global deallocation
- /// function in C++1y. If so, find and return the corresponding unsized
- /// deallocation function.
- FunctionDecl *getCorrespondingUnsizedGlobalDeallocationFunction() const;
-
/// Compute the language linkage.
LanguageLinkage getLanguageLinkage() const;
LANGOPT(AssumeSaneOperatorNew , 1, 1, "implicit __attribute__((malloc)) for C++'s new operators")
LANGOPT(SizedDeallocation , 1, 0, "enable sized deallocation functions")
-LANGOPT(DefineSizedDeallocation , 1, 0, "generate weak definitions of sized delete")
BENIGN_LANGOPT(ElideConstructors , 1, 1, "C++ copy constructor elision")
BENIGN_LANGOPT(DumpRecordLayouts , 1, 0, "dumping the layout of IRgen'd records")
BENIGN_LANGOPT(DumpRecordLayoutsSimple , 1, 0, "dumping the layout of IRgen'd records in a simple form")
HelpText<"Defines the __DEPRECATED macro">;
def fno_deprecated_macro : Flag<["-"], "fno-deprecated-macro">,
HelpText<"Undefines the __DEPRECATED macro">;
-def fsized_deallocation : Flag<["-"], "fsized-deallocation">,
- HelpText<"Enable C++14 sized global deallocation functions">;
-def fno_sized_deallocation: Flag<["-"], "fno-sized-deallocation">,
- HelpText<"Disable sized deallocation functions">;
-def fdefine_sized_deallocation: Flag<["-"], "fdefine-sized-deallocation">,
- HelpText<"Allow compiler-generated definition of sized deallocation functions">;
def fobjc_subscripting_legacy_runtime : Flag<["-"], "fobjc-subscripting-legacy-runtime">,
HelpText<"Allow Objective-C array and dictionary subscripting in legacy runtime">;
def vtordisp_mode_EQ : Joined<["-"], "vtordisp-mode=">,
HelpText<"Restrict code to those available for App Extensions">;
def fno_application_extension : Flag<["-"], "fno-application-extension">,
Group<f_Group>;
+def fsized_deallocation : Flag<["-"], "fsized-deallocation">, Flags<[CC1Option]>,
+ HelpText<"Enable C++14 sized global deallocation functions">, Group<f_Group>;
+def fno_sized_deallocation: Flag<["-"], "fno-sized-deallocation">, Group<f_Group>;
def fobjc_gc_only : Flag<["-"], "fobjc-gc-only">, Group<f_Group>, Flags<[CC1Option]>,
HelpText<"Use GC exclusively for Objective-C related memory management">;
return RD && isNamed(RD, "nothrow_t") && RD->isInStdNamespace();
}
-FunctionDecl *
-FunctionDecl::getCorrespondingUnsizedGlobalDeallocationFunction() const {
- ASTContext &Ctx = getASTContext();
- if (!Ctx.getLangOpts().SizedDeallocation)
- return nullptr;
-
- if (getDeclName().getNameKind() != DeclarationName::CXXOperatorName)
- return nullptr;
- if (getDeclName().getCXXOverloadedOperator() != OO_Delete &&
- getDeclName().getCXXOverloadedOperator() != OO_Array_Delete)
- return nullptr;
- if (isa<CXXRecordDecl>(getDeclContext()))
- return nullptr;
-
- if (!getDeclContext()->getRedeclContext()->isTranslationUnit())
- return nullptr;
-
- if (getNumParams() != 2 || isVariadic() ||
- !Ctx.hasSameType(getType()->castAs<FunctionProtoType>()->getParamType(1),
- Ctx.getSizeType()))
- return nullptr;
-
- // This is a sized deallocation function. Find the corresponding unsized
- // deallocation function.
- lookup_result R = getDeclContext()->lookup(getDeclName());
- for (lookup_result::iterator RI = R.begin(), RE = R.end(); RI != RE;
- ++RI)
- if (FunctionDecl *FD = dyn_cast<FunctionDecl>(*RI))
- if (FD->getNumParams() == 1 && !FD->isVariadic())
- return FD;
- return nullptr;
-}
-
LanguageLinkage FunctionDecl::getLanguageLinkage() const {
return getDeclLanguageLinkage(*this);
}
F->setDoesNotThrow();
}
-static void EmitSizedDeallocationFunction(CodeGenFunction &CGF,
- const FunctionDecl *UnsizedDealloc) {
- // This is a weak discardable definition of the sized deallocation function.
- CGF.CurFn->setLinkage(llvm::Function::LinkOnceAnyLinkage);
- if (CGF.CGM.supportsCOMDAT())
- CGF.CurFn->setComdat(
- CGF.CGM.getModule().getOrInsertComdat(CGF.CurFn->getName()));
-
- // Call the unsized deallocation function and forward the first argument
- // unchanged.
- llvm::Constant *Unsized = CGF.CGM.GetAddrOfFunction(UnsizedDealloc);
- CGF.Builder.CreateCall(Unsized, &*CGF.CurFn->arg_begin());
-}
-
void CodeGenFunction::GenerateCode(GlobalDecl GD, llvm::Function *Fn,
const CGFunctionInfo &FnInfo) {
const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
emitImplicitAssignmentOperatorBody(Args);
} else if (Stmt *Body = FD->getBody()) {
EmitFunctionBody(Args, Body);
- } else if (FunctionDecl *UnsizedDealloc =
- FD->getCorrespondingUnsizedGlobalDeallocationFunction()) {
- // Global sized deallocation functions get an implicit weak definition if
- // they don't have an explicit definition, if allowed.
- assert(getLangOpts().DefineSizedDeallocation &&
- "Can't emit unallowed definition.");
- EmitSizedDeallocationFunction(*this, UnsizedDealloc);
-
} else
llvm_unreachable("no definition for emitted function");
// don't need it anymore).
addDeferredDeclToEmit(F, DDI->second);
DeferredDecls.erase(DDI);
-
- // Otherwise, if this is a sized deallocation function, emit a weak
- // definition for it at the end of the translation unit (if allowed),
- // unless the sized deallocation function is aliased.
- } else if (D &&
- cast<FunctionDecl>(D)
- ->getCorrespondingUnsizedGlobalDeallocationFunction() &&
- getLangOpts().DefineSizedDeallocation &&
- !D->hasAttr<AliasAttr>()) {
- addDeferredDeclToEmit(F, GD);
// Otherwise, there are cases we have to worry about where we're
// using a declaration for which we must emit a definition but where
options::OPT_fno_assume_sane_operator_new))
CmdArgs.push_back("-fno-assume-sane-operator-new");
+ // -fsized-deallocation is off by default, as it is an ABI-breaking change for
+ // most platforms.
+ if (Args.hasFlag(options::OPT_fsized_deallocation,
+ options::OPT_fno_sized_deallocation, false))
+ CmdArgs.push_back("-fsized-deallocation");
+
// -fconstant-cfstrings is default, and may be subject to argument translation
// on Darwin.
if (!Args.hasFlag(options::OPT_fconstant_cfstrings,
Opts.CXXOperatorNames = Opts.CPlusPlus;
Opts.DollarIdents = !Opts.AsmPreprocessor;
-
- // C++14 onwards has sized global deallocation functions.
- Opts.SizedDeallocation = Opts.CPlusPlus14;
}
/// Attempt to parse a visibility value out of the given argument.
Opts.NoBuiltin = Args.hasArg(OPT_fno_builtin) || Opts.Freestanding;
Opts.NoMathBuiltin = Args.hasArg(OPT_fno_math_builtin);
Opts.AssumeSaneOperatorNew = !Args.hasArg(OPT_fno_assume_sane_operator_new);
- Opts.SizedDeallocation |= Args.hasArg(OPT_fsized_deallocation);
- Opts.SizedDeallocation &= !Args.hasArg(OPT_fno_sized_deallocation);
- Opts.DefineSizedDeallocation = Opts.SizedDeallocation &&
- Args.hasArg(OPT_fdefine_sized_deallocation);
+ Opts.SizedDeallocation = Args.hasArg(OPT_fsized_deallocation);
Opts.HeinousExtensions = Args.hasArg(OPT_fheinous_gnu_extensions);
Opts.AccessControl = !Args.hasArg(OPT_fno_access_control);
Opts.ElideConstructors = !Args.hasArg(OPT_fno_elide_constructors);
}
}
}
-
- // If the function is sized operator delete and has not already been
- // declared, and weak definitions have been disabled, do not declare
- // it implicitly. Instead, let deallocation function lookup pick up
- // unsized delete.
- // FIXME: We should remove this guard once backward compatibility is
- // no longer an issue
- if (NumParams == 2 && !getLangOpts().DefineSizedDeallocation)
- return;
FunctionProtoType::ExtProtoInfo EPI;
inline void* operator new[](size_t) BAD_ALLOC; // expected-error {{cannot be declared 'inline'}}
inline void operator delete(void*) NOEXCEPT; // expected-error {{cannot be declared 'inline'}}
inline void operator delete[](void*) NOEXCEPT; // expected-error {{cannot be declared 'inline'}}
-#if __cplusplus >= 201402L
+#ifdef __cpp_sized_deallocation
inline void operator delete(void*, size_t) NOEXCEPT; // expected-error {{cannot be declared 'inline'}}
inline void operator delete[](void*, size_t) NOEXCEPT; // expected-error {{cannot be declared 'inline'}}
#endif
-// RUN: %clang_cc1 -std=c++1y %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s --check-prefix=CHECK-UNSIZED
-// RUN: %clang_cc1 -std=c++1y %s -emit-llvm -triple x86_64-linux-gnu -o - -DINLIB | FileCheck %s --check-prefix=CHECK --check-prefix=CHECKUND
-// RUN: %clang_cc1 -std=c++1y %s -emit-llvm -triple x86_64-linux-gnu -fdefine-sized-deallocation -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECKDEF
-// RUN: %clang_cc1 -std=c++11 -fsized-deallocation %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s --check-prefix=CHECK-UNSIZED
-// RUN: %clang_cc1 -std=c++11 -fsized-deallocation %s -emit-llvm -triple x86_64-linux-gnu -o - -DINLIB | FileCheck %s --check-prefix=CHECK --check-prefix=CHECKUND
-// RUN: %clang_cc1 -std=c++11 -fsized-deallocation -fdefine-sized-deallocation %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECKDEF
+// Check that delete exprs call the sized deallocation function if
+// -fsized-deallocation is passed in both C++11 and C++14.
+// RUN: %clang_cc1 -std=c++11 -fsized-deallocation %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s
+// RUN: %clang_cc1 -std=c++14 -fsized-deallocation %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s
+
+// Check that we don't used sized deallocation without -fsized-deallocation and
+// C++14.
// RUN: %clang_cc1 -std=c++11 %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s --check-prefix=CHECK-UNSIZED
-// RUN: %clang_cc1 -std=c++1y %s -emit-llvm -triple x86_64-linux-gnu -fno-sized-deallocation -o - | FileCheck %s --check-prefix=CHECK-UNSIZED
+// RUN: %clang_cc1 -std=c++14 %s -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s --check-prefix=CHECK-UNSIZED
// CHECK-UNSIZED-NOT: _ZdlPvm
// CHECK-UNSIZED-NOT: _ZdaPvm
typedef decltype(sizeof(0)) size_t;
-#ifdef INLIB
-void operator delete(void *, size_t) noexcept;
-void operator delete[](void *, size_t) noexcept;
-#endif
-
typedef int A;
struct B { int n; };
struct C { ~C() {} };
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 4)
// CHECK: call void @_ZdaPv(i8* %{{[^ ]*}})
-// CHECKDEF-LABEL: define linkonce void @_ZdlPvm(i8*, i64) #{{[0-9]+}} comdat
-// CHECKDEF: call void @_ZdlPv(i8* %0)
-// CHECKUND-LABEL: declare void @_ZdlPvm(i8*
+// CHECK-LABEL: declare void @_ZdlPvm(i8*
// CHECK-LABEL: define weak_odr void @_Z3delI1BEvv()
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 4)
// CHECK: add i64 %{{[^ ]*}}, 8
// CHECK: call void @_ZdaPvm(i8* %{{[^ ]*}}, i64 %{{[^ ]*}})
-// CHECKDEF-LABEL: define linkonce void @_ZdaPvm(i8*, i64) #{{[0-9]+}} comdat
-// CHECKDEF: call void @_ZdaPv(i8* %0)
-// CHECKUND-LABEL: declare void @_ZdaPvm(i8*
+// CHECK-LABEL: declare void @_ZdaPvm(i8*
// CHECK-LABEL: define weak_odr void @_Z3delI1DEvv()
// CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 8)
+++ /dev/null
-// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-unknown -o - -std=c++11 %s 2>&1 | FileCheck %s -check-prefix=CHECKDEF -check-prefix=CHECK11
-// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-unknown -o - -std=c++11 -fvisibility hidden %s 2>&1 | FileCheck %s -check-prefix=CHECKHID -check-prefix=CHECK11
-// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-unknown -o - -std=c++14 -DINLIB -fno-sized-deallocation %s 2>&1 | FileCheck %s -check-prefix=CHECKDEF -check-prefix=CHECK11
-// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-unknown -o - -std=c++14 -DINLIB %s 2>&1 | FileCheck %s -check-prefix=CHECKDEF -check-prefix=CHECK14 -check-prefix=CHECK14UND
-// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-unknown -o - -std=c++14 -DINLIB -fvisibility hidden %s 2>&1 | FileCheck %s -check-prefix=CHECKHID -check-prefix=CHECK14 -check-prefix=CHECK14UND
-// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-unknown -o - -std=c++14 -DINLIB -fdefine-sized-deallocation %s 2>&1 | FileCheck %s -check-prefix=CHECKDEF -check-prefix=CHECK14 -check-prefix=CHECK14DEFCOMDAT
-// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-unknown -o - -std=c++14 -DINLIB -fdefine-sized-deallocation -fvisibility hidden %s 2>&1 | FileCheck %s -check-prefix=CHECKHID -check-prefix=CHECK14 -check-prefix=CHECK14DEFCOMDAT
-// RUN: %clang_cc1 -emit-llvm -triple x86_64-apple-macosx -o - -std=c++14 -DINLIB -fdefine-sized-deallocation %s | FileCheck %s -check-prefix=CHECKDEF -check-prefix=CHECK14 -check-prefix=CHECK14DEFNOCOMDAT
-
-// PR22419: Implicit sized deallocation functions always have default visibility.
-// Generalized to all implicit allocation functions.
-
-#ifdef INLIB
-typedef decltype(sizeof(0)) size_t;
-void operator delete(void *, size_t) noexcept;
-void operator delete[](void *, size_t) noexcept;
-#endif
-
-// CHECK14-DAG: %struct.A = type { i8 }
-struct A { };
-
-// CHECKDEF-DAG: define void @_Z3fooP1A(%struct.A* %is)
-// CHECKHID-DAG: define hidden void @_Z3fooP1A(%struct.A* %is)
-void foo(A* is) {
-
- // CHECK11-DAG: call noalias i8* @_Znwm(i64 1)
- // CHECK14-DAG: call noalias i8* @_Znwm(i64 1)
- is = new A();
-
- // CHECK11-DAG: call void @_ZdlPv(i8* %{{.+}})
- // CHECK14-DAG: call void @_ZdlPvm(i8* %{{.+}}, i64 1)
- delete is;
-}
-
-// CHECK11-DAG: declare noalias i8* @_Znwm(i64)
-// CHECK11-DAG: declare void @_ZdlPv(i8*)
-
-// CHECK14-DAG: declare noalias i8* @_Znwm(i64)
-// CHECK14UND-DAG: declare void @_ZdlPvm(i8*, i64)
-// CHECK14DEFCOMDAT-DAG: define linkonce void @_ZdlPvm(i8*, i64) #{{[0-9]+}} comdat {
-// CHECK14DEFCOMDAT-DAG: declare void @_ZdlPv(i8*)
-// CHECK14DEFNOCOMDAT-DAG: define linkonce void @_ZdlPvm(i8*, i64) #{{[0-9]+}} {
-// CHECK14DEFNOCOMDAT-DAG: declare void @_ZdlPv(i8*)
-
-// CHECK14-DAG: %struct.B = type { i8 }
-struct B { ~B() { }};
-
-// CHECKDEF-DAG: define void @_Z1fP1B(%struct.B* %p)
-// CHECKHID-DAG: define hidden void @_Z1fP1B(%struct.B* %p)
-void f(B *p) {
-
- // CHECK11-DAG: call noalias i8* @_Znam(i64 13)
- // CHECK14-DAG: call noalias i8* @_Znam(i64 13)
- p = new B[5];
-
- // CHECK11-DAG: call void @_ZdaPv(i8* %{{.+}})
- // CHECK14-DAG: call void @_ZdaPvm(i8* %{{.+}}, i64 %{{.+}})
- delete[] p;
-}
-
-// CHECK11-DAG: declare noalias i8* @_Znam(i64)
-// CHECK11-DAG: declare void @_ZdaPv(i8*)
-
-// CHECK14-DAG: declare noalias i8* @_Znam(i64)
-// CHECK14UND-DAG: declare void @_ZdaPvm(i8*, i64)
-// CHECK14DEF-DAG: define linkonce void @_ZdaPvm(i8*, i64) #{{[0-9]+}} comdat {
-// CHECK14DEF-DAG: declare void @_ZdaPv(i8*)
-// CHECK14DEFNOCOMDAT-DAG: define linkonce void @_ZdaPvm(i8*, i64) #{{[0-9]+}} {
-// CHECK14DEFNOCOMDAT-DAG: declare void @_ZdaPv(i8*)
+++ /dev/null
-// RUN: %clang -cc1 -emit-llvm -triple x86_64-unknown-unknown -std=c++1y -o - %s 2>&1 | FileCheck %s
-// RUN: %clang -cc1 -emit-llvm -triple x86_64-unknown-unknown -std=c++1y -fdefine-sized-deallocation -o - %s 2>&1 | FileCheck %s
-// RUN: %clang -cc1 -emit-llvm -triple x86_64-unknown-unknown -std=c++1y -fno-sized-deallocation -o - %s 2>&1 | FileCheck %s
-// RUN: %clang -cc1 -emit-llvm -triple x86_64-unknown-unknown -std=c++11 -fsized-deallocation -o - %s 2>&1 | FileCheck %s
-// RUN: %clang -cc1 -emit-llvm -triple x86_64-unknown-unknown -std=c++11 -fsized-deallocation -fdefine-sized-deallocation -o - %s 2>&1 | FileCheck %s
-// RUN: %clang -cc1 -emit-llvm -triple x86_64-unknown-unknown -std=c++11 -o - %s 2>&1 | FileCheck %s
-
-void operator delete(void*, unsigned long) throw() __attribute__((alias("foo")));
-extern "C" void foo(void*, unsigned long) {}
-
-// CHECK-DAG: @_ZdlPvm = alias void (i8*, i64)* @foo
// RUN: %clang_cc1 -std=c++98 -verify %s
// RUN: %clang_cc1 -std=c++11 -verify %s
-// RUN: %clang_cc1 -std=c++1y -verify %s
+// RUN: %clang_cc1 -std=c++1y -fsized-deallocation -verify %s
// expected-no-diagnostics
<td class="full" align="center">Clang 3.4 <a href="#n3778">(6)</a></td>
</tr>
</table>
+
<p>
-<span id="n3778">(6): In Clang SVN, using sized deallocation in C++14 mode requires linking either
-libc++ 3.7 or later, or libstdc++ 5 or later. Alternatively, you can use the
-<code>-Xclang -fdefine-sized-deallocation</code> compiler option to enable the implementation from
-Clang 3.4 through Clang 3.6, where weak definitions of sized deallocation functions are implicitly
-generated (by the compiler). You can also use the <code>-Xclang -fno-sized-deallocation</code> option
-to disable sized deallocation. Note that both of these flags are temporary provisions and may go away
-soon.
+<span id="n3778">(6): In Clang 3.7 and later, sized deallocation is only enabled
+if the user passes the <code>-fsized-deallocation</code> flag. The user must
+supply definitions of the sized deallocation functions, either by providing them
+explicitly or by using a C++ standard library that does. <code>libstdc++</code>
+added these functions in version 5.0, and <code>libc++</code> added them in
+version 3.7.
</span>
</p>