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.
Larisse Voufo
lvoufo at google.com
Tue Feb 17 17:07:08 PST 2015
On Sun, Feb 15, 2015 at 6:10 PM, Richard Smith <richard at metafoo.co.uk>
wrote:
> 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?
>
Thanks, Richard. Please see r229597 for the above comments.
>
> 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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