virtual void emitThrow(CodeGenFunction &CGF, const CXXThrowExpr *E) = 0;
virtual llvm::GlobalVariable *getThrowInfo(QualType T) { return nullptr; }
- virtual bool canEmitAvailableExternallyVTable(
- const CXXRecordDecl *RD) const = 0;
+ /// \brief Determine whether it's possible to emit a vtable for \p RD, even
+ /// though we do not know that the vtable has been marked as used by semantic
+ /// analysis.
+ virtual bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const = 0;
virtual void emitBeginCatch(CodeGenFunction &CGF, const CXXCatchStmt *C) = 0;
// with a vtable. We don't do this for base subobjects for two reasons:
// first, it's incorrect for classes with virtual bases, and second, we're
// about to overwrite the vptrs anyway.
+ // We also have to make sure if we can refer to vtable:
+ // - If vtable is external then it's safe to use it (for available_externally
+ // CGVTables will make sure if it can emit it).
+ // - Otherwise we can refer to vtable if it's safe to speculatively emit.
+ // FIXME: If vtable is used by ctor/dtor, we are always safe to refer to it.
if (CGM.getCodeGenOpts().OptimizationLevel > 0 &&
- ClassDecl->isDynamicClass() && Type != Ctor_Base)
+ ClassDecl->isDynamicClass() && Type != Ctor_Base &&
+ (CGM.getVTables().isVTableExternal(ClassDecl) ||
+ CGM.getCXXABI().canSpeculativelyEmitVTable(ClassDecl)))
EmitVTableAssumptionLoads(ClassDecl, This);
}
static bool shouldEmitAvailableExternallyVTable(const CodeGenModule &CGM,
const CXXRecordDecl *RD) {
return CGM.getCodeGenOpts().OptimizationLevel > 0 &&
- CGM.getCXXABI().canEmitAvailableExternallyVTable(RD);
+ CGM.getCXXABI().canSpeculativelyEmitVTable(RD);
}
/// Compute the required linkage of the v-table for the given class.
/// we define that v-table?
static bool shouldEmitVTableAtEndOfTranslationUnit(CodeGenModule &CGM,
const CXXRecordDecl *RD) {
- // If vtable is internal then it has to be done
+ // If vtable is internal then it has to be done.
if (!CGM.getVTables().isVTableExternal(RD))
return true;
- // If it's external then maybe we will need it as available_externally
+ // If it's external then maybe we will need it as available_externally.
return shouldEmitAvailableExternallyVTable(CGM, RD);
}
void emitVirtualInheritanceTables(const CXXRecordDecl *RD) override;
- bool canEmitAvailableExternallyVTable(const CXXRecordDecl *RD) const override;
+ bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const override;
void setThunkLinkage(llvm::Function *Thunk, bool ForVTable, GlobalDecl GD,
bool ReturnAdjustment) override {
VTables.EmitVTTDefinition(VTT, CGM.getVTableLinkage(RD), RD);
}
-bool ItaniumCXXABI::canEmitAvailableExternallyVTable(
- const CXXRecordDecl *RD) const {
+bool ItaniumCXXABI::canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const {
// We don't emit available_externally vtables if we are in -fapple-kext mode
// because kext mode does not permit devirtualization.
if (CGM.getLangOpts().AppleKext)
QualType DestTy) override;
bool EmitBadCastCall(CodeGenFunction &CGF) override;
- bool canEmitAvailableExternallyVTable(
- const CXXRecordDecl *RD) const override {
+ bool canSpeculativelyEmitVTable(const CXXRecordDecl *RD) const override {
return false;
}
// RUN: %clang_cc1 %s -O1 -disable-llvm-optzns -triple=x86_64-apple-darwin10 -emit-llvm -o - | FileCheck %s
-// CHECK: @_ZTVN5test018stdio_sync_filebufIA4_iEE = linkonce_odr unnamed_addr constant
-
// CHECK: @_ZN7PR100011xE = global
// CHECK-NOT: @_ZN7PR100014kBarE = external global i32
//
// CHECK: @_ZN7PR100011SIiE3arrE = linkonce_odr global [3 x i32]
// CHECK-NOT: @_ZN7PR100011SIiE3arr2E = linkonce_odr global [3 x i32]A
+// CHECK: @_ZTVN5test018stdio_sync_filebufIA4_iEE = linkonce_odr unnamed_addr constant
// CHECK-NOT: _ZTVN5test31SIiEE
// CHECK-NOT: _ZTSN5test31SIiEE
// Checking with opt
// CHECK-OPT-LABEL: define internal void @_ZThn8_N6Test4B12_GLOBAL__N_11C1fEv(%"struct.Test4B::(anonymous namespace)::C"* %this) unnamed_addr #0 align 2
+// This is from Test5:
+// CHECK-OPT-LABEL: define linkonce_odr void @_ZTv0_n24_N5Test51B1fEv
+
// This is from Test10:
// CHECK-OPT-LABEL: define linkonce_odr void @_ZN6Test101C3fooEv
// CHECK-OPT-LABEL: define linkonce_odr void @_ZThn8_N6Test101C3fooEv
-// This is from Test5:
-// CHECK-OPT-LABEL: define linkonce_odr void @_ZTv0_n24_N5Test51B1fEv
+
// CHECK: attributes [[NUW]] = { nounwind uwtable{{.*}} }
// RUN: FileCheck --check-prefix=CHECK3 --input-file=%t.ll %s
// RUN: FileCheck --check-prefix=CHECK4 --input-file=%t.ll %s
// RUN: FileCheck --check-prefix=CHECK-MS --input-file=%t.ms.ll %s
-
+// RUN: FileCheck --check-prefix=CHECK6 --input-file=%t.ll %s
+// RUN: FileCheck --check-prefix=CHECK7 --input-file=%t.ll %s
+// RUN: FileCheck --check-prefix=CHECK8 --input-file=%t.ll %s
namespace test1 {
struct A {
}
} // test4
-namespace test5 {
+namespace testMS {
struct __declspec(novtable) S {
virtual void foo();
void g(S &s) { s.foo(); }
// if struct has novtable specifier, then we can't generate assumes
-// CHECK-MS-LABEL: define void @"\01?test@test5@@YAXXZ"()
-// CHECK-MS: call x86_thiscallcc %"struct.test5::S"* @"\01??0S@test5@@QAE@XZ"(
+// CHECK-MS-LABEL: define void @"\01?test@testMS@@YAXXZ"()
+// CHECK-MS: call x86_thiscallcc %"struct.testMS::S"* @"\01??0S@testMS@@QAE@XZ"(
// CHECK-MS-NOT: @llvm.assume
// CHECK-MS-LABEL: }
g(s);
}
-} // test5
+} // testMS
+
+namespace test6 {
+// CHECK6: @_ZTVN5test61AE = external
+struct A {
+ A();
+ virtual void foo();
+ virtual ~A() {}
+};
+struct B : A {
+ B();
+};
+// Because A's vtable is external, it's safe to generate assumption loads.
+// CHECK6-LABEL: define void @_ZN5test61gEv()
+// CHECK6: call void @_ZN5test61AC1Ev(
+// CHECK6: call void @llvm.assume(
+
+// We can't emit assumption loads for B, because if we would refer to vtable
+// it would refer to functions that will not be able to find (like implicit
+// inline destructor).
+
+// CHECK6-LABEL: call void @_ZN5test61BC1Ev(
+// CHECK6-NOT: call void @llvm.assume(
+// CHECK6-LABEL: }
+void g() {
+ A *a = new A;
+ B *b = new B;
+}
+
+}
+
+namespace test7 {
+// Because A's key function is defined here, vtable is generated in this TU
+// CHECK7: @_ZTVN5test71AE = unnamed_addr constant
+struct A {
+ A();
+ virtual void foo();
+ virtual void bar();
+};
+void A::foo() {}
+
+// CHECK7-LABEL: define void @_ZN5test71gEv()
+// CHECK7: call void @_ZN5test71AC1Ev(
+// CHECK7: call void @llvm.assume(
+// CHECK7-LABEL: }
+void g() {
+ A *a = new A();
+ a->bar();
+}
+}
+
+namespace test8 {
+
+struct A {
+ virtual void foo();
+ virtual void bar();
+};
+
+// CHECK8-DAG: @_ZTVN5test81BE = available_externally unnamed_addr constant
+struct B : A {
+ B();
+ void foo();
+ void bar();
+};
+
+// CHECK8-DAG: @_ZTVN5test81CE = linkonce_odr unnamed_addr constant
+struct C : A {
+ C();
+ void bar();
+ void foo() {}
+};
+inline void C::bar() {}
+
+// CHECK8-DAG: @_ZTVN5test81DE = external unnamed_addr constant
+struct D : A {
+ D();
+ void foo();
+ void inline bar();
+};
+void D::bar() {}
+
+// CHECK8-DAG: @_ZTVN5test81EE = linkonce_odr unnamed_addr constant
+struct E : A {
+ E();
+};
+
+// CHECK8-LABEL: define void @_ZN5test81bEv()
+// CHECK8: call void @llvm.assume(
+// CHECK8-LABEL: }
+void b() {
+ B b;
+ b.bar();
+}
+
+// FIXME: C has inline virtual functions which prohibits as from generating
+// assumption loads, but because vtable is generated in this TU (key function
+// defined here) it would be correct to refer to it.
+// CHECK8-LABEL: define void @_ZN5test81cEv()
+// CHECK8-NOT: call void @llvm.assume(
+// CHECK8-LABEL: }
+void c() {
+ C c;
+ c.bar();
+}
+
+// CHECK8-LABEL: define void @_ZN5test81dEv()
+// CHECK8: call void @llvm.assume(
+// CHECK8-LABEL: }
+void d() {
+ D d;
+ d.bar();
+}
+
+// CHECK8-LABEL: define void @_ZN5test81eEv()
+// CHECK8: call void @llvm.assume(
+// CHECK8-LABEL: }
+void e() {
+ E e;
+ e.bar();
+}
+}
+
} // Test8
namespace Test9 {
-// all virtual functions are outline, so we can assume that it will
-// be generated in translation unit where foo is defined
+// All virtual functions are outline, so we can assume that it will
+// be generated in translation unit where foo is defined.
// CHECK-TEST9-DAG: @_ZTVN5Test91AE = available_externally unnamed_addr constant
// CHECK-TEST9-DAG: @_ZTVN5Test91BE = available_externally unnamed_addr constant
struct A {
};
void A::foo() {}
-// Because key function is inline we will generate vtable as linkonce_odr
+// Because key function is inline we will generate vtable as linkonce_odr.
// CHECK-TEST10-DAG: @_ZTVN6Test101DE = linkonce_odr unnamed_addr constant
struct D : A {
void bar();
};
inline void D::bar() {}
-// because B has outline key function then we can refer to
+// Because B has outline all virtual functions, we can refer to them.
// CHECK-TEST10-DAG: @_ZTVN6Test101BE = available_externally unnamed_addr constant
struct B : A {
void foo();
// C's key function (car) is outline, but C has inline virtual function so we
// can't guarantee that we will be able to refer to bar from name
-// so (at the moment) we can't emit vtable available_externally
+// so (at the moment) we can't emit vtable available_externally.
// CHECK-TEST10-DAG: @_ZTVN6Test101CE = external unnamed_addr constant
struct C : A {
void bar() {} // defined in body - not key function
}
}
-
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