r285664 - Implement ABI proposal for throwing noexcept function pointers, per discussion
Richard Smith via cfe-commits
cfe-commits at lists.llvm.org
Mon Oct 31 18:34:46 PDT 2016
Author: rsmith
Date: Mon Oct 31 20:34:46 2016
New Revision: 285664
URL: http://llvm.org/viewvc/llvm-project?rev=285664&view=rev
Log:
Implement ABI proposal for throwing noexcept function pointers, per discussion
on cxx-abi-dev (thread starting 2016-10-11). This is currently hidden behind a
cc1-only -m flag, pending discussion of how best to deal with language changes
that require use of new symbols from the ABI library.
Added:
cfe/trunk/test/CodeGenCXX/rtti-qualfn.cpp
Modified:
cfe/trunk/include/clang/Driver/CC1Options.td
cfe/trunk/include/clang/Frontend/CodeGenOptions.def
cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp
cfe/trunk/lib/Frontend/CompilerInvocation.cpp
cfe/trunk/www/cxx_status.html
Modified: cfe/trunk/include/clang/Driver/CC1Options.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Driver/CC1Options.td?rev=285664&r1=285663&r2=285664&view=diff
==============================================================================
--- cfe/trunk/include/clang/Driver/CC1Options.td (original)
+++ cfe/trunk/include/clang/Driver/CC1Options.td Mon Oct 31 20:34:46 2016
@@ -251,6 +251,8 @@ def munwind_tables : Flag<["-"], "munwin
HelpText<"Generate unwinding tables for all functions">;
def mconstructor_aliases : Flag<["-"], "mconstructor-aliases">,
HelpText<"Emit complete constructors and destructors as aliases when possible">;
+def mqualified_function_type_info : Flag<["-"], "mqualified-function-type-info">,
+ HelpText<"Emit __qualified_function_type_info for qualified function types">;
def mlink_bitcode_file : Separate<["-"], "mlink-bitcode-file">,
HelpText<"Link the given bitcode file before performing optimizations.">;
def mlink_cuda_bitcode : Separate<["-"], "mlink-cuda-bitcode">,
Modified: cfe/trunk/include/clang/Frontend/CodeGenOptions.def
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Frontend/CodeGenOptions.def?rev=285664&r1=285663&r2=285664&view=diff
==============================================================================
--- cfe/trunk/include/clang/Frontend/CodeGenOptions.def (original)
+++ cfe/trunk/include/clang/Frontend/CodeGenOptions.def Mon Oct 31 20:34:46 2016
@@ -133,6 +133,7 @@ CODEGENOPT(DumpCoverageMapping , 1, 0) /
/// If -fpcc-struct-return or -freg-struct-return is specified.
ENUM_CODEGENOPT(StructReturnConvention, StructReturnConventionKind, 2, SRCK_Default)
+CODEGENOPT(QualifiedFunctionTypeInfo, 1, 0) ///< Use __qualified_function_type_info.
CODEGENOPT(RelaxAll , 1, 0) ///< Relax all machine code instructions.
CODEGENOPT(RelaxedAliasing , 1, 0) ///< Set when -fno-strict-aliasing is enabled.
CODEGENOPT(StructPathTBAA , 1, 0) ///< Whether or not to use struct-path TBAA.
Modified: cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp?rev=285664&r1=285663&r2=285664&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp (original)
+++ cfe/trunk/lib/CodeGen/ItaniumCXXABI.cpp Mon Oct 31 20:34:46 2016
@@ -46,6 +46,7 @@ protected:
bool UseARMMethodPtrABI;
bool UseARMGuardVarABI;
bool Use32BitVTableOffsetABI;
+ bool UseQualifiedFunctionTypeInfoABI;
ItaniumMangleContext &getMangleContext() {
return cast<ItaniumMangleContext>(CodeGen::CGCXXABI::getMangleContext());
@@ -57,7 +58,8 @@ public:
bool UseARMGuardVarABI = false) :
CGCXXABI(CGM), UseARMMethodPtrABI(UseARMMethodPtrABI),
UseARMGuardVarABI(UseARMGuardVarABI),
- Use32BitVTableOffsetABI(false) { }
+ Use32BitVTableOffsetABI(false),
+ UseQualifiedFunctionTypeInfoABI(CGM.getCodeGenOpts().QualifiedFunctionTypeInfo) { }
bool classifyReturnType(CGFunctionInfo &FI) const override;
@@ -2427,6 +2429,9 @@ class ItaniumRTTIBuilder {
/// descriptor of the given type.
llvm::Constant *GetAddrOfExternalRTTIDescriptor(QualType Ty);
+ /// Determine whether FnTy should be emitted as a qualified function type.
+ bool EmitAsQualifiedFunctionType(const FunctionType *FnTy);
+
/// BuildVTablePointer - Build the vtable pointer for the given type.
void BuildVTablePointer(const Type *Ty);
@@ -2439,6 +2444,10 @@ class ItaniumRTTIBuilder {
/// constraints, according ti the Itanium C++ ABI, 2.9.5p5c.
void BuildVMIClassTypeInfo(const CXXRecordDecl *RD);
+ /// Build an abi::__qualified_function_type_info struct, used for function
+ /// types with various kinds of qualifiers.
+ void BuildQualifiedFunctionTypeInfo(const FunctionType *FnTy);
+
/// BuildPointerTypeInfo - Build an abi::__pointer_type_info struct, used
/// for pointer types.
void BuildPointerTypeInfo(QualType PointeeTy);
@@ -2455,6 +2464,27 @@ public:
ItaniumRTTIBuilder(const ItaniumCXXABI &ABI)
: CGM(ABI.CGM), VMContext(CGM.getModule().getContext()), CXXABI(ABI) {}
+ // Function type info flags.
+ enum {
+ /// Qualifiers for 'this' pointer of member function type.
+ //@{
+ QFTI_Const = 0x1,
+ QFTI_Volatile = 0x2,
+ QFTI_Restrict = 0x4,
+ QFTI_LValRef = 0x8,
+ QFTI_RValRef = 0x10,
+ //@}
+
+ /// Noexcept function qualifier (C++17 onwards).
+ QFTI_Noexcept = 0x20,
+
+ // Transaction-safe function qualifier (Transactional Memory TS).
+ //QFTI_TxSafe = 0x40,
+
+ /// Noreturn function type qualifier (GNU/Clang extension).
+ QFTI_Noreturn = 0x80
+ };
+
// Pointer type info flags.
enum {
/// PTI_Const - Type has const qualifier.
@@ -2806,8 +2836,12 @@ void ItaniumRTTIBuilder::BuildVTablePoin
case Type::FunctionNoProto:
case Type::FunctionProto:
- // abi::__function_type_info.
- VTableName = "_ZTVN10__cxxabiv120__function_type_infoE";
+ if (EmitAsQualifiedFunctionType(cast<FunctionType>(Ty)))
+ // abi::__qualified_function_type_info.
+ VTableName = "_ZTVN10__cxxabiv130__qualified_function_type_infoE";
+ else
+ // abi::__function_type_info.
+ VTableName = "_ZTVN10__cxxabiv120__function_type_infoE";
break;
case Type::Enum:
@@ -3021,10 +3055,15 @@ llvm::Constant *ItaniumRTTIBuilder::Buil
break;
case Type::FunctionNoProto:
- case Type::FunctionProto:
+ case Type::FunctionProto: {
+ auto *FnTy = cast<FunctionType>(Ty);
// Itanium C++ ABI 2.9.5p5:
// abi::__function_type_info adds no data members to std::type_info.
+ if (EmitAsQualifiedFunctionType(FnTy))
+ // abi::__qualified_type_info adds a base function type and qualifiers.
+ BuildQualifiedFunctionTypeInfo(FnTy);
break;
+ }
case Type::Enum:
// Itanium C++ ABI 2.9.5p5:
@@ -3319,6 +3358,72 @@ void ItaniumRTTIBuilder::BuildVMIClassTy
}
}
+bool ItaniumRTTIBuilder::EmitAsQualifiedFunctionType(const FunctionType *FnTy) {
+ if (!CXXABI.UseQualifiedFunctionTypeInfoABI)
+ return false;
+
+ auto *FPT = dyn_cast<FunctionProtoType>(FnTy);
+ if (!FPT)
+ return false;
+ return FPT->getTypeQuals() || FPT->getRefQualifier() != RQ_None ||
+ FPT->isNothrow(CXXABI.getContext()) || FPT->getNoReturnAttr();
+}
+
+void ItaniumRTTIBuilder::BuildQualifiedFunctionTypeInfo(
+ const FunctionType *FnTy) {
+ unsigned int Qualifiers = 0;
+
+ auto ExtInfo = FnTy->getExtInfo();
+ if (ExtInfo.getNoReturn()) {
+ Qualifiers |= QFTI_Noreturn;
+ ExtInfo = ExtInfo.withNoReturn(false);
+ }
+
+ QualType BaseType;
+ if (auto *FPT = dyn_cast<FunctionProtoType>(FnTy)) {
+ auto EPI = FPT->getExtProtoInfo();
+ EPI.ExtInfo = ExtInfo;
+
+ if (EPI.TypeQuals & Qualifiers::Const)
+ Qualifiers |= QFTI_Const;
+ if (EPI.TypeQuals & Qualifiers::Volatile)
+ Qualifiers |= QFTI_Volatile;
+ if (EPI.TypeQuals & Qualifiers::Restrict)
+ Qualifiers |= QFTI_Restrict;
+ EPI.TypeQuals = 0;
+
+ if (EPI.RefQualifier == RQ_LValue)
+ Qualifiers |= QFTI_LValRef;
+ else if (EPI.RefQualifier == RQ_RValue)
+ Qualifiers |= QFTI_RValRef;
+ EPI.RefQualifier = RQ_None;
+
+ if (EPI.ExceptionSpec.Type == EST_BasicNoexcept)
+ Qualifiers |= QFTI_Noexcept;
+ else
+ assert(EPI.ExceptionSpec.Type == EST_None &&
+ "unexpected canonical non-dependent exception spec");
+ EPI.ExceptionSpec.Type = EST_None;
+
+ BaseType = CXXABI.getContext().getFunctionType(FPT->getReturnType(),
+ FPT->getParamTypes(), EPI);
+ } else {
+ BaseType =
+ QualType(CXXABI.getContext().adjustFunctionType(FnTy, ExtInfo), 0);
+ }
+
+ assert(Qualifiers && "should not have created qualified type info");
+
+ // __base_type is a pointer to the std::type_info derivation for the
+ // unqualified version of the function type.
+ Fields.push_back(ItaniumRTTIBuilder(CXXABI).BuildTypeInfo(BaseType));
+
+ // __qualifiers is a flag word describing the qualifiers of the function type.
+ llvm::Type *UnsignedIntLTy =
+ CGM.getTypes().ConvertType(CGM.getContext().UnsignedIntTy);
+ Fields.push_back(llvm::ConstantInt::get(UnsignedIntLTy, Qualifiers));
+}
+
/// BuildPointerTypeInfo - Build an abi::__pointer_type_info struct,
/// used for pointer types.
void ItaniumRTTIBuilder::BuildPointerTypeInfo(QualType PointeeTy) {
Modified: cfe/trunk/lib/Frontend/CompilerInvocation.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInvocation.cpp?rev=285664&r1=285663&r2=285664&view=diff
==============================================================================
--- cfe/trunk/lib/Frontend/CompilerInvocation.cpp (original)
+++ cfe/trunk/lib/Frontend/CompilerInvocation.cpp Mon Oct 31 20:34:46 2016
@@ -553,6 +553,7 @@ static bool ParseCodeGenArgs(CodeGenOpti
Opts.ObjCAutoRefCountExceptions = Args.hasArg(OPT_fobjc_arc_exceptions);
Opts.CXAAtExit = !Args.hasArg(OPT_fno_use_cxa_atexit);
Opts.CXXCtorDtorAliases = Args.hasArg(OPT_mconstructor_aliases);
+ Opts.QualifiedFunctionTypeInfo = Args.hasArg(OPT_mqualified_function_type_info);
Opts.CodeModel = getCodeModel(Args, Diags);
Opts.DebugPass = Args.getLastArgValue(OPT_mdebug_pass);
Opts.DisableFPElim =
Added: cfe/trunk/test/CodeGenCXX/rtti-qualfn.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/rtti-qualfn.cpp?rev=285664&view=auto
==============================================================================
--- cfe/trunk/test/CodeGenCXX/rtti-qualfn.cpp (added)
+++ cfe/trunk/test/CodeGenCXX/rtti-qualfn.cpp Mon Oct 31 20:34:46 2016
@@ -0,0 +1,51 @@
+// RUN: %clang_cc1 -std=c++1z -mqualified-function-type-info -I%S %s -triple x86_64-linux-gnu -emit-llvm -o - -fcxx-exceptions | FileCheck %s
+
+#include "typeinfo"
+
+struct A {};
+
+// CHECK-DAG: @_ZTIKFvvE = [[QFTI:linkonce_odr constant { i8\*, i8\*, i8\*, i32 } { i8\* bitcast \(i8\*\* getelementptr inbounds \(i8\*, i8\*\* @_ZTVN10__cxxabiv130__qualified_function_type_infoE, i64 2\) to i8\*\),]] i8* getelementptr inbounds ([6 x i8], [6 x i8]* @_ZTSKFvvE, i32 0, i32 0), i8* bitcast ({ i8*, i8* }* @_ZTIFvvE to i8*), i32 1 }, comdat
+// CHECK-DAG: @_ZTIM1AKFvvE = [[PMFTI:linkonce_odr constant { i8\*, i8\*, i32, i8\*, i8\* } { i8\* bitcast \(i8\*\* getelementptr inbounds \(i8\*, i8\*\* @_ZTVN10__cxxabiv129__pointer_to_member_type_infoE, i64 2\) to i8\*\),]] i8* getelementptr inbounds ([9 x i8], [9 x i8]* @_ZTSM1AKFvvE, i32 0, i32 0), i32 0, i8* bitcast ({ i8*, i8*, i8*, i32 }* @_ZTIKFvvE to i8*), i8* bitcast ({ i8*, i8* }* @_ZTI1A to i8*) }, comdat
+auto &ti_const = typeid(void (A::*)() const);
+
+// CHECK-DAG: @_ZTIVFvvE = [[QFTI]] {{.*}} @_ZTIFvvE {{.*}}, i32 2 }, comdat
+// CHECK-DAG: @_ZTIM1AVFvvE = [[PMFTI]] {{.*}}), i32 0, {{.*}} @_ZTIVFvvE
+auto &ti_volatile = typeid(void (A::*)() volatile);
+
+// CHECK-DAG: @_ZTIrFvvE = [[QFTI]] {{.*}} @_ZTIFvvE {{.*}}, i32 4 }, comdat
+// CHECK-DAG: @_ZTIM1ArFvvE = [[PMFTI]] {{.*}}), i32 0, {{.*}} @_ZTIrFvvE
+auto &ti_restrict = typeid(void (A::*)() __restrict);
+
+// CHECK-DAG: @_ZTIFvvRE = [[QFTI]] {{.*}} @_ZTIFvvE {{.*}}, i32 8 }, comdat
+// CHECK-DAG: @_ZTIM1AFvvRE = [[PMFTI]] {{.*}}), i32 0, {{.*}} @_ZTIFvvRE
+auto &ti_lref = typeid(void (A::*)() &);
+
+// CHECK-DAG: @_ZTIFvvOE = [[QFTI]] {{.*}} @_ZTIFvvE {{.*}}, i32 16 }, comdat
+// CHECK-DAG: @_ZTIM1AFvvOE = [[PMFTI]] {{.*}}), i32 0, {{.*}} @_ZTIFvvOE
+auto &ti_rref = typeid(void (A::*)() &&);
+
+// CHECK-DAG: @_ZTInxFvvE = [[QFTI]] {{.*}} @_ZTIFvvE {{.*}}, i32 32 }, comdat
+// CHECK-DAG: @_ZTIM1AnxFvvE = [[PMFTI]] {{.*}}), i32 0, {{.*}} @_ZTInxFvvE
+auto &ti_noexcept = typeid(void (A::*)() noexcept);
+
+//auto &ti_txsafe = typeid(void (A::*)() transaction_safe);
+
+// FIXME: Produce the typeinfo for a noreturn function type here?
+// CHECK-DAG: @_ZTIM1AFvvE = [[PMFTI]] {{.*}}), i32 0, {{.*}} @_ZTIFvvE
+auto &ti_noreturn = typeid(void __attribute__((noreturn)) (A::*)());
+
+// CHECK-DAG: @_ZTIrVKnxFvvRE = [[QFTI]] {{.*}} @_ZTIFvvE {{.*}}, i32 47 }, comdat
+// CHECK-DAG: @_ZTIM1ArVKnxFvvRE = [[PMFTI]] {{.*}}), i32 0, {{.*}} @_ZTIrVKnxFvvRE
+auto &ti_rainbow = typeid(void (A::*)() const volatile __restrict & noexcept);
+
+// CHECK-LABEL: define void @_Z1fv(
+__attribute__((noreturn)) void f() noexcept {
+ // CHECK: call void @__cxa_throw({{.*}}@_ZTIPnxFvvE
+ throw f;
+}
+
+// CHECK-LABEL: define void @_Z1gM1AnxFvvE(
+void g(__attribute__((noreturn)) void (A::*p)() noexcept) {
+ // CHECK: call void @__cxa_throw({{.*}}@_ZTIM1AnxFvvE
+ throw p;
+}
Modified: cfe/trunk/www/cxx_status.html
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/www/cxx_status.html?rev=285664&r1=285663&r2=285664&view=diff
==============================================================================
--- cfe/trunk/www/cxx_status.html (original)
+++ cfe/trunk/www/cxx_status.html Mon Oct 31 20:34:46 2016
@@ -612,9 +612,7 @@ as the draft C++1z standard evolves.
<tr>
<td>Make exception specifications part of the type system</td>
<td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0012r1.html">P0012R1</a></td>
- <td class="partial" align="center">Partial</td>
- <!-- We don't correctly support throwing noexcept function types and
- catching as non-noexcept yet. -->
+ <td class="svn" align="center">SVN <a href="#p0012">(9)</a></td>
</tr>
<tr>
<td><tt>__has_include</tt> in preprocessor conditionals</td>
@@ -624,7 +622,7 @@ as the draft C++1z standard evolves.
<tr>
<td>New specification for inheriting constructors (<a href="cxx_dr_status.html#1941">DR1941</a> et al)</td>
<td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0136r1.html">P0136R1</a></td>
- <td class="full" align="center">Clang 3.9 <a href="#p0136">(9)</a></td>
+ <td class="full" align="center">Clang 3.9 <a href="#p0136">(10)</a></td>
</tr>
<!-- Jacksonville papers -->
<tr>
@@ -701,7 +699,7 @@ as the draft C++1z standard evolves.
<tr>
<td rowspan=2>Stricter expression evaluation order</td>
<td><a href="http://wg21.link/p0145r3">P0145R3</a></td>
- <td class="svn" align="center" rowspan=2>SVN <a href="#p0145">(10)</a></td>
+ <td class="svn" align="center" rowspan=2>SVN <a href="#p0145">(11)</a></td>
</tr>
<tr>
<td><a href="http://wg21.link/p0400r0">P0400R0</a></td>
@@ -741,10 +739,18 @@ all language versions that allow type de
(per the request of the C++ committee).
In Clang 3.7, a warning is emitted for all cases that would change meaning.
</span><br>
-<span id="p0136">(9): This is the resolution to a Defect Report, so is applied
+<span id="p0012">(9): Support for throwing a noexcept function pointer and
+catching it as a non-noexcept function pointer requires an ABI library with
+C++17 support. Currently, only libc++abi 4.0 provides this support, so this
+portion of the feature is disabled by default. If you are using a sufficiently
+recent ABI library, you can enable support for this feature with the
+<code>-Xclang -mqualified-function-type-info</code> flag. This flag is likely
+to be removed or replaced in future Clang releases.
+</span><br>
+<span id="p0136">(10): This is the resolution to a Defect Report, so is applied
to all language versions supporting inheriting constructors.
</span><br>
-<span id="p0145">(10): Under the MS ABI, function parameters are destroyed from
+<span id="p0145">(11): Under the MS ABI, function parameters are destroyed from
left to right in the callee. As a result, function parameters in calls to
<tt>operator<<</tt>, <tt>operator>></tt>, <tt>operator->*</tt>,
<tt>operator&&</tt>, <tt>operator||</tt>, and <tt>operator,</tt>
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