r229241 - Revise the implementation logic of sized deallocation: Do not automatically generate weak definitions of the sized operator delete (in terms of unsized operator delete). Instead, provide the funcitonality via a new compiler flag, -fdef-sized-delete.
Richard Smith
richard at metafoo.co.uk
Sun Feb 15 18:10:17 PST 2015
On Fri, Feb 13, 2015 at 9:42 PM, Larisse Voufo <lvoufo at google.com> wrote:
> Author: lvoufo
> Date: Fri Feb 13 23:42:57 2015
> New Revision: 229241
>
> URL: http://llvm.org/viewvc/llvm-project?rev=229241&view=rev
> Log:
> Revise the implementation logic of sized deallocation: Do not
> automatically generate weak definitions of the sized operator delete (in
> terms of unsized operator delete). Instead, provide the funcitonality via a
> new compiler flag, -fdef-sized-delete.
> The current implementation causes link-time ODR violations when the delete
> symbols are exported into the dynamic table.
>
> Modified:
> cfe/trunk/include/clang/Basic/LangOptions.def
> cfe/trunk/include/clang/Driver/Options.td
> cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
> cfe/trunk/lib/CodeGen/CodeGenModule.cpp
> cfe/trunk/lib/Driver/Tools.cpp
> cfe/trunk/lib/Frontend/CompilerInvocation.cpp
> cfe/trunk/test/CodeGenCXX/cxx1y-sized-deallocation.cpp
> cfe/trunk/test/CodeGenCXX/implicit-allocation-functions.cpp
>
> Modified: cfe/trunk/include/clang/Basic/LangOptions.def
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/LangOptions.def?rev=229241&r1=229240&r2=229241&view=diff
>
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/LangOptions.def (original)
> +++ cfe/trunk/include/clang/Basic/LangOptions.def Fri Feb 13 23:42:57 2015
> @@ -162,6 +162,7 @@ LANGOPT(CUDAIsDevice , 1, 0, "Compi
>
> LANGOPT(AssumeSaneOperatorNew , 1, 1, "implicit __attribute__((malloc))
> for C++'s new operators")
> LANGOPT(SizedDeallocation , 1, 0, "enable sized deallocation functions")
> +LANGOPT(DefaultSizedDelete , 1, 0, "Generate weak definitions of sized
> delete")
>
Please start this string with a lowercase letter. How about
DefineSizedDeallocation, to match the existing SizedDeallocation LangOpt?
("Define" seems like a better word than "Default" here in any case.)
> 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")
>
> Modified: cfe/trunk/include/clang/Driver/Options.td
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/Options.td?rev=229241&r1=229240&r2=229241&view=diff
>
> ==============================================================================
> --- cfe/trunk/include/clang/Driver/Options.td (original)
> +++ cfe/trunk/include/clang/Driver/Options.td Fri Feb 13 23:42:57 2015
> @@ -394,6 +394,8 @@ def fasm_blocks : Flag<["-"], "fasm-bloc
> def fno_asm_blocks : Flag<["-"], "fno-asm-blocks">, Group<f_Group>;
>
> def fassume_sane_operator_new : Flag<["-"], "fassume-sane-operator-new">,
> Group<f_Group>;
> +def fdef_sized_delete: Flag<["-"], "fdef-sized-delete">, Group<f_Group>,
> + HelpText<"Allow compiler-generated definition of sized deallocation
> function">, Flags<[CC1Option]>;
>
Likewise here, how about -fdefine-sized-deallocation, to match the existing
-fsized-deallocation flag?
def fastcp : Flag<["-"], "fastcp">, Group<f_Group>;
> def fastf : Flag<["-"], "fastf">, Group<f_Group>;
> def fast : Flag<["-"], "fast">, Group<f_Group>;
>
> Modified: cfe/trunk/lib/CodeGen/CodeGenFunction.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenFunction.cpp?rev=229241&r1=229240&r2=229241&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CodeGenFunction.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CodeGenFunction.cpp Fri Feb 13 23:42:57 2015
> @@ -891,8 +891,11 @@ void CodeGenFunction::GenerateCode(Globa
> } else if (FunctionDecl *UnsizedDealloc =
> FD->getCorrespondingUnsizedGlobalDeallocationFunction())
> {
> // Global sized deallocation functions get an implicit weak
> definition if
> - // they don't have an explicit definition.
> + // they don't have an explicit definition, if allowed.
> + assert(getLangOpts().DefaultSizedDelete &&
> + "Can't emit unallowed definition.");
> EmitSizedDeallocationFunction(*this, UnsizedDealloc);
> +
> } else
> llvm_unreachable("no definition for emitted function");
>
>
> Modified: cfe/trunk/lib/CodeGen/CodeGenModule.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.cpp?rev=229241&r1=229240&r2=229241&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CodeGenModule.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CodeGenModule.cpp Fri Feb 13 23:42:57 2015
> @@ -1615,13 +1615,13 @@ CodeGenModule::GetOrCreateLLVMFunction(S
> // 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.
> + // definition for it at the end of the translation unit.
> } else if (D && cast<FunctionDecl>(D)
>
> ->getCorrespondingUnsizedGlobalDeallocationFunction()) {
> - addDeferredDeclToEmit(F, GD);
> + if (getLangOpts().DefaultSizedDelete)
> + 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
>
> Modified: cfe/trunk/lib/Driver/Tools.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=229241&r1=229240&r2=229241&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Driver/Tools.cpp (original)
> +++ cfe/trunk/lib/Driver/Tools.cpp Fri Feb 13 23:42:57 2015
> @@ -4243,6 +4243,11 @@ void Clang::ConstructJob(Compilation &C,
> if (!Args.hasFlag(options::OPT_fassume_sane_operator_new,
> options::OPT_fno_assume_sane_operator_new))
> CmdArgs.push_back("-fno-assume-sane-operator-new");
> +
> + // -def-sized-delete: default implementation of sized delete as a
> + // weak definition.
> + if (Args.hasArg(options::OPT_fdef_sized_delete))
> + CmdArgs.push_back("-fdef-sized-delete");
>
> // -fconstant-cfstrings is default, and may be subject to argument
> translation
> // on Darwin.
>
> Modified: cfe/trunk/lib/Frontend/CompilerInvocation.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInvocation.cpp?rev=229241&r1=229240&r2=229241&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Frontend/CompilerInvocation.cpp (original)
> +++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp Fri Feb 13 23:42:57 2015
> @@ -1525,6 +1525,8 @@ static void ParseLangArgs(LangOptions &O
> 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.DefaultSizedDelete = Opts.SizedDeallocation &&
> + Args.hasArg(OPT_fdef_sized_delete);
> Opts.HeinousExtensions = Args.hasArg(OPT_fheinous_gnu_extensions);
> Opts.AccessControl = !Args.hasArg(OPT_fno_access_control);
> Opts.ElideConstructors = !Args.hasArg(OPT_fno_elide_constructors);
>
> Modified: cfe/trunk/test/CodeGenCXX/cxx1y-sized-deallocation.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/cxx1y-sized-deallocation.cpp?rev=229241&r1=229240&r2=229241&view=diff
>
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/cxx1y-sized-deallocation.cpp (original)
> +++ cfe/trunk/test/CodeGenCXX/cxx1y-sized-deallocation.cpp Fri Feb 13
> 23:42:57 2015
> @@ -1,5 +1,7 @@
> -// RUN: %clang_cc1 -std=c++1y %s -emit-llvm -triple x86_64-linux-gnu -o -
> | FileCheck %s
> -// RUN: %clang_cc1 -std=c++11 -fsized-deallocation %s -emit-llvm -triple
> x86_64-linux-gnu -o - | FileCheck %s
> +// RUN: %clang_cc1 -std=c++1y %s -emit-llvm -triple x86_64-linux-gnu -o -
> | FileCheck %s --check-prefix=CHECK --check-prefix=CHECKUND
> +// RUN: %clang_cc1 -std=c++1y %s -emit-llvm -triple x86_64-linux-gnu
> -fdef-sized-delete -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
> --check-prefix=CHECKUND
> +// RUN: %clang_cc1 -std=c++11 -fsized-deallocation -fdef-sized-delete %s
> -emit-llvm -triple x86_64-linux-gnu -o - | FileCheck %s
> --check-prefix=CHECK --check-prefix=CHECKDEF
> // RUN: %clang_cc1 -std=c++11 %s -emit-llvm -triple x86_64-linux-gnu -o -
> | FileCheck %s --check-prefix=CHECK-UNSIZED
>
> // CHECK-UNSIZED-NOT: _ZdlPvm
> @@ -50,8 +52,9 @@ D::D() {}
> // CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 4)
> // CHECK: call void @_ZdaPv(i8* %{{[^ ]*}})
>
> -// CHECK-LABEL: define linkonce void @_ZdlPvm(i8*
> -// CHECK: call void @_ZdlPv(i8* %0)
> +// CHECKDEF-LABEL: define linkonce void @_ZdlPvm(i8*
> +// CHECKDEF: call void @_ZdlPv(i8* %0)
> +// CHECKUND-LABEL: declare void @_ZdlPvm(i8*
>
> // CHECK-LABEL: define weak_odr void @_Z3delI1BEvv()
> // CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 4)
> @@ -71,8 +74,9 @@ D::D() {}
> // CHECK: add i64 %{{[^ ]*}}, 8
> // CHECK: call void @_ZdaPvm(i8* %{{[^ ]*}}, i64 %{{[^ ]*}})
>
> -// CHECK-LABEL: define linkonce void @_ZdaPvm(i8*
> -// CHECK: call void @_ZdaPv(i8* %0)
> +// CHECKDEF-LABEL: define linkonce void @_ZdaPvm(i8*
> +// CHECKDEF: call void @_ZdaPv(i8* %0)
> +// CHECKUND-LABEL: declare void @_ZdaPvm(i8*
>
> // CHECK-LABEL: define weak_odr void @_Z3delI1DEvv()
> // CHECK: call void @_ZdlPvm(i8* %{{[^ ]*}}, i64 8)
>
> Modified: cfe/trunk/test/CodeGenCXX/implicit-allocation-functions.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/implicit-allocation-functions.cpp?rev=229241&r1=229240&r2=229241&view=diff
>
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/implicit-allocation-functions.cpp (original)
> +++ cfe/trunk/test/CodeGenCXX/implicit-allocation-functions.cpp Fri Feb 13
> 23:42:57 2015
> @@ -1,7 +1,9 @@
> // 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 %s 2>&1 | FileCheck %s -check-prefix=CHECKDEF
> -check-prefix=CHECK14
> -// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-unknown -o -
> -std=c++14 -fvisibility hidden %s 2>&1 | FileCheck %s
> -check-prefix=CHECKHID -check-prefix=CHECK14
> +// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-unknown -o -
> -std=c++14 %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 -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 -fdef-sized-delete %s 2>&1 | FileCheck %s -check-prefix=CHECKDEF
> -check-prefix=CHECK14 -check-prefix=CHECK14DEF
> +// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-unknown -o -
> -std=c++14 -fdef-sized-delete -fvisibility hidden %s 2>&1 | FileCheck %s
> -check-prefix=CHECKHID -check-prefix=CHECK14 -check-prefix=CHECK14DEF
>
> // PR22419: Implicit sized deallocation functions always have default
> visibility.
> // Generalized to all implicit allocation functions.
> @@ -27,8 +29,9 @@ void foo(A* is) {
> // CHECK11-DAG: declare void @_ZdlPv(i8*)
>
> // CHECK14-DAG: declare noalias i8* @_Znwm(i64)
> -// CHECK14-DAG: define linkonce void @_ZdlPvm(i8*, i64)
> -// CHECK14-DAG: declare void @_ZdlPv(i8*)
> +// CHECK14UND-DAG: declare void @_ZdlPvm(i8*, i64)
> +// CHECK14DEF-DAG: define linkonce void @_ZdlPvm(i8*, i64)
> +// CHECK14DEF-DAG: declare void @_ZdlPv(i8*)
>
> // CHECK14-DAG: %struct.B = type { i8 }
> struct B { ~B() { }};
> @@ -50,5 +53,6 @@ void f(B *p) {
> // CHECK11-DAG: declare void @_ZdaPv(i8*)
>
> // CHECK14-DAG: declare noalias i8* @_Znam(i64)
> -// CHECK14-DAG: define linkonce void @_ZdaPvm(i8*, i64)
> -// CHECK14-DAG: declare void @_ZdaPv(i8*)
> +// CHECK14UND-DAG: declare void @_ZdaPvm(i8*, i64)
> +// CHECK14DEF-DAG: define linkonce void @_ZdaPvm(i8*, i64)
> +// CHECK14DEF-DAG: declare void @_ZdaPv(i8*)
>
Please can you update cxx_status.html and the Clang 3.7 release notes to
note that we now require one of (a) libc++ 3.7 or later, (b) libstdc++ 5 or
later, (c) -fdefine-sized-deallocation, or (d) -fno-sized-deallocation to
build code in C++14 mode? Thanks.
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