[clang] 3933c43 - [clang] Add cc1 option -fctor-dtor-return-this
Shu-Chun Weng via cfe-commits
cfe-commits at lists.llvm.org
Mon Oct 3 14:28:29 PDT 2022
Author: Shu-Chun Weng
Date: 2022-10-03T14:28:06-07:00
New Revision: 3933c43d9008bb1b151156da92827a109e7963b6
URL: https://github.com/llvm/llvm-project/commit/3933c43d9008bb1b151156da92827a109e7963b6
DIFF: https://github.com/llvm/llvm-project/commit/3933c43d9008bb1b151156da92827a109e7963b6.diff
LOG: [clang] Add cc1 option -fctor-dtor-return-this
This option forces constructors and non-deleting destructors to return
`this` pointer in C++ ABI (except for Microsoft ABI, on which this flag
has no effect).
This is similar to ARM32, Apple ARM64, or Fuchsia C++ ABI, but can be
applied to any target triple.
Differential Revision: https://reviews.llvm.org/D119209
Added:
Modified:
clang/include/clang/Basic/CodeGenOptions.def
clang/include/clang/Driver/Options.td
clang/lib/CodeGen/CGCXXABI.h
clang/lib/CodeGen/ItaniumCXXABI.cpp
clang/test/CodeGenCXX/constructor-destructor-return-this.cpp
Removed:
################################################################################
diff --git a/clang/include/clang/Basic/CodeGenOptions.def b/clang/include/clang/Basic/CodeGenOptions.def
index ddeabfc9d5451..62d0c936c60a5 100644
--- a/clang/include/clang/Basic/CodeGenOptions.def
+++ b/clang/include/clang/Basic/CodeGenOptions.def
@@ -492,6 +492,10 @@ ENUM_CODEGENOPT(ZeroCallUsedRegs, llvm::ZeroCallUsedRegs::ZeroCallUsedRegsKind,
/// Whether to use opaque pointers.
CODEGENOPT(OpaquePointers, 1, 0)
+/// Modify C++ ABI to returning `this` pointer from constructors and
+/// non-deleting destructors. (No effect on Microsoft ABI.)
+CODEGENOPT(CtorDtorReturnThis, 1, 0)
+
#undef CODEGENOPT
#undef ENUM_CODEGENOPT
#undef VALUE_CODEGENOPT
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index 655bf0d58d8e1..b6130f3410830 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -5604,6 +5604,11 @@ def ehcontguard : Flag<["-"], "ehcontguard">,
def fdenormal_fp_math_f32_EQ : Joined<["-"], "fdenormal-fp-math-f32=">,
Group<f_Group>;
+def fctor_dtor_return_this : Flag<["-"], "fctor-dtor-return-this">,
+ HelpText<"Change the C++ ABI to returning `this` pointer from constructors "
+ "and non-deleting destructors. (No effect on Microsoft ABI)">,
+ MarshallingInfoFlag<CodeGenOpts<"CtorDtorReturnThis">>;
+
} // let Flags = [CC1Option, NoDriverOption]
//===----------------------------------------------------------------------===//
diff --git a/clang/lib/CodeGen/CGCXXABI.h b/clang/lib/CodeGen/CGCXXABI.h
index 0768e6581acb8..a600768b20746 100644
--- a/clang/lib/CodeGen/CGCXXABI.h
+++ b/clang/lib/CodeGen/CGCXXABI.h
@@ -105,6 +105,10 @@ class CGCXXABI {
/// final class will have been taken care of by the caller.
virtual bool isThisCompleteObject(GlobalDecl GD) const = 0;
+ virtual bool constructorsAndDestructorsReturnThis() const {
+ return CGM.getCodeGenOpts().CtorDtorReturnThis;
+ }
+
public:
virtual ~CGCXXABI();
@@ -120,7 +124,13 @@ class CGCXXABI {
///
/// There currently is no way to indicate if a destructor returns 'this'
/// when called virtually, and code generation does not support the case.
- virtual bool HasThisReturn(GlobalDecl GD) const { return false; }
+ virtual bool HasThisReturn(GlobalDecl GD) const {
+ if (isa<CXXConstructorDecl>(GD.getDecl()) ||
+ (isa<CXXDestructorDecl>(GD.getDecl()) &&
+ GD.getDtorType() != Dtor_Deleting))
+ return constructorsAndDestructorsReturnThis();
+ return false;
+ }
virtual bool hasMostDerivedReturn(GlobalDecl GD) const { return false; }
diff --git a/clang/lib/CodeGen/ItaniumCXXABI.cpp b/clang/lib/CodeGen/ItaniumCXXABI.cpp
index cb97af7ab11ab..c84faf468ea22 100644
--- a/clang/lib/CodeGen/ItaniumCXXABI.cpp
+++ b/clang/lib/CodeGen/ItaniumCXXABI.cpp
@@ -433,11 +433,7 @@ class ARMCXXABI : public ItaniumCXXABI {
ItaniumCXXABI(CGM, /*UseARMMethodPtrABI=*/true,
/*UseARMGuardVarABI=*/true) {}
- bool HasThisReturn(GlobalDecl GD) const override {
- return (isa<CXXConstructorDecl>(GD.getDecl()) || (
- isa<CXXDestructorDecl>(GD.getDecl()) &&
- GD.getDtorType() != Dtor_Deleting));
- }
+ bool constructorsAndDestructorsReturnThis() const override { return true; }
void EmitReturnFromThunk(CodeGenFunction &CGF, RValue RV,
QualType ResTy) override;
@@ -468,11 +464,7 @@ class FuchsiaCXXABI final : public ItaniumCXXABI {
: ItaniumCXXABI(CGM) {}
private:
- bool HasThisReturn(GlobalDecl GD) const override {
- return isa<CXXConstructorDecl>(GD.getDecl()) ||
- (isa<CXXDestructorDecl>(GD.getDecl()) &&
- GD.getDtorType() != Dtor_Deleting);
- }
+ bool constructorsAndDestructorsReturnThis() const override { return true; }
};
class WebAssemblyCXXABI final : public ItaniumCXXABI {
@@ -486,11 +478,7 @@ class WebAssemblyCXXABI final : public ItaniumCXXABI {
llvm::Value *Exn) override;
private:
- bool HasThisReturn(GlobalDecl GD) const override {
- return isa<CXXConstructorDecl>(GD.getDecl()) ||
- (isa<CXXDestructorDecl>(GD.getDecl()) &&
- GD.getDtorType() != Dtor_Deleting);
- }
+ bool constructorsAndDestructorsReturnThis() const override { return true; }
bool canCallMismatchedFunctionType() const override { return false; }
};
diff --git a/clang/test/CodeGenCXX/constructor-destructor-return-this.cpp b/clang/test/CodeGenCXX/constructor-destructor-return-this.cpp
index f8ed023df4ee5..3951211eb1974 100644
--- a/clang/test/CodeGenCXX/constructor-destructor-return-this.cpp
+++ b/clang/test/CodeGenCXX/constructor-destructor-return-this.cpp
@@ -6,6 +6,8 @@
//RUN: %clang_cc1 -no-opaque-pointers %s -emit-llvm -o - -triple=x86_64-unknown-fuchsia | FileCheck --check-prefix=CHECKFUCHSIA %s
//RUN: %clang_cc1 -no-opaque-pointers %s -emit-llvm -o - -triple=aarch64-unknown-fuchsia | FileCheck --check-prefix=CHECKFUCHSIA %s
//RUN: %clang_cc1 -no-opaque-pointers %s -emit-llvm -o - -triple=i386-pc-win32 -fno-rtti | FileCheck --check-prefix=CHECKMS %s
+//RUN: %clang_cc1 -no-opaque-pointers %s -emit-llvm -o - -triple=i686-unknown-linux-gnu -fctor-dtor-return-this | FileCheck --check-prefix=CHECKI686RET %s
+//RUN: %clang_cc1 -no-opaque-pointers %s -emit-llvm -o - -triple=aarch64-unknown-linux-gnu -fctor-dtor-return-this | FileCheck --check-prefix=CHECKAARCH64RET %s
// FIXME: these tests crash on the bots when run with -triple=x86_64-pc-win32
// Make sure we attach the 'returned' attribute to the 'this' parameter of
@@ -37,10 +39,15 @@ B::~B() { }
// CHECKGEN-LABEL: define{{.*}} void @_ZN1BD2Ev(%class.B* {{[^,]*}} %this)
// CHECKGEN-LABEL: define{{.*}} void @_ZN1BD1Ev(%class.B* {{[^,]*}} %this)
-// CHECKARM-LABEL: define{{.*}} %class.B* @_ZN1BC2EPi(%class.B* {{[^,]*}} returned{{[^,]*}} %this, i32* noundef %i)
-// CHECKARM-LABEL: define{{.*}} %class.B* @_ZN1BC1EPi(%class.B* {{[^,]*}} returned{{[^,]*}} %this, i32* noundef %i)
-// CHECKARM-LABEL: define{{.*}} %class.B* @_ZN1BD2Ev(%class.B* {{[^,]*}} returned{{[^,]*}} %this)
-// CHECKARM-LABEL: define{{.*}} %class.B* @_ZN1BD1Ev(%class.B* {{[^,]*}} returned{{[^,]*}} %this)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.B* @_ZN1BC2EPi(%class.B* {{[^,]*}} returned{{[^,]*}} %this, i32* noundef %i)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.B* @_ZN1BC1EPi(%class.B* {{[^,]*}} returned{{[^,]*}} %this, i32* noundef %i)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.B* @_ZN1BD2Ev(%class.B* {{[^,]*}} returned{{[^,]*}} %this)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.B* @_ZN1BD1Ev(%class.B* {{[^,]*}} returned{{[^,]*}} %this)
+
+// CHECKI686RET-LABEL: define{{.*}} %class.B* @_ZN1BC2EPi(%class.B* {{[^,]*}} %this, i32* noundef %i)
+// CHECKI686RET-LABEL: define{{.*}} %class.B* @_ZN1BC1EPi(%class.B* {{[^,]*}} %this, i32* noundef %i)
+// CHECKI686RET-LABEL: define{{.*}} %class.B* @_ZN1BD2Ev(%class.B* {{[^,]*}} %this)
+// CHECKI686RET-LABEL: define{{.*}} %class.B* @_ZN1BD1Ev(%class.B* {{[^,]*}} %this)
// CHECKIOS5-LABEL: define{{.*}} %class.B* @_ZN1BC2EPi(%class.B* {{[^,]*}} %this, i32* noundef %i)
// CHECKIOS5-LABEL: define{{.*}} %class.B* @_ZN1BC1EPi(%class.B* {{[^,]*}} %this, i32* noundef %i)
@@ -74,13 +81,23 @@ C::~C() { }
// CHECKGEN-LABEL: define{{.*}} void @_ZN1CD0Ev(%class.C* {{[^,]*}} %this)
// CHECKGEN-LABEL: define{{.*}} void @_ZThn8_N1CD0Ev(%class.C* noundef %this)
-// CHECKARM-LABEL: define{{.*}} %class.C* @_ZN1CC2EPiPc(%class.C* {{[^,]*}} returned{{[^,]*}} %this, i32* noundef %i, i8* noundef %c)
-// CHECKARM-LABEL: define{{.*}} %class.C* @_ZN1CC1EPiPc(%class.C* {{[^,]*}} returned{{[^,]*}} %this, i32* noundef %i, i8* noundef %c)
-// CHECKARM-LABEL: define{{.*}} %class.C* @_ZN1CD2Ev(%class.C* {{[^,]*}} returned{{[^,]*}} %this)
-// CHECKARM-LABEL: define{{.*}} %class.C* @_ZN1CD1Ev(%class.C* {{[^,]*}} returned{{[^,]*}} %this)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.C* @_ZN1CC2EPiPc(%class.C* {{[^,]*}} returned{{[^,]*}} %this, i32* noundef %i, i8* noundef %c)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.C* @_ZN1CC1EPiPc(%class.C* {{[^,]*}} returned{{[^,]*}} %this, i32* noundef %i, i8* noundef %c)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.C* @_ZN1CD2Ev(%class.C* {{[^,]*}} returned{{[^,]*}} %this)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.C* @_ZN1CD1Ev(%class.C* {{[^,]*}} returned{{[^,]*}} %this)
// CHECKARM-LABEL: define{{.*}} %class.C* @_ZThn8_N1CD1Ev(%class.C* noundef %this)
-// CHECKARM-LABEL: define{{.*}} void @_ZN1CD0Ev(%class.C* {{[^,]*}} %this)
+// CHECKAARCH64RET-LABEL: define{{.*}} %class.C* @_ZThn16_N1CD1Ev(%class.C* noundef %this)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} void @_ZN1CD0Ev(%class.C* {{[^,]*}} %this)
// CHECKARM-LABEL: define{{.*}} void @_ZThn8_N1CD0Ev(%class.C* noundef %this)
+// CHECKAARCH64RET-LABEL: define{{.*}} void @_ZThn16_N1CD0Ev(%class.C* noundef %this)
+
+// CHECKI686RET-LABEL: define{{.*}} %class.C* @_ZN1CC2EPiPc(%class.C* {{[^,]*}} %this, i32* noundef %i, i8* noundef %c)
+// CHECKI686RET-LABEL: define{{.*}} %class.C* @_ZN1CC1EPiPc(%class.C* {{[^,]*}} %this, i32* noundef %i, i8* noundef %c)
+// CHECKI686RET-LABEL: define{{.*}} %class.C* @_ZN1CD2Ev(%class.C* {{[^,]*}} %this)
+// CHECKI686RET-LABEL: define{{.*}} %class.C* @_ZN1CD1Ev(%class.C* {{[^,]*}} %this)
+// CHECKI686RET-LABEL: define{{.*}} %class.C* @_ZThn8_N1CD1Ev(%class.C* noundef %this)
+// CHECKI686RET-LABEL: define{{.*}} void @_ZN1CD0Ev(%class.C* {{[^,]*}} %this)
+// CHECKI686RET-LABEL: define{{.*}} void @_ZThn8_N1CD0Ev(%class.C* noundef %this)
// CHECKIOS5-LABEL: define{{.*}} %class.C* @_ZN1CC2EPiPc(%class.C* {{[^,]*}} %this, i32* noundef %i, i8* noundef %c)
// CHECKIOS5-LABEL: define{{.*}} %class.C* @_ZN1CC1EPiPc(%class.C* {{[^,]*}} %this, i32* noundef %i, i8* noundef %c)
@@ -115,10 +132,15 @@ D::~D() { }
// CHECKGEN-LABEL: define{{.*}} void @_ZN1DD2Ev(%class.D* {{[^,]*}} %this, i8** noundef %vtt)
// CHECKGEN-LABEL: define{{.*}} void @_ZN1DD1Ev(%class.D* {{[^,]*}} %this)
-// CHECKARM-LABEL: define{{.*}} %class.D* @_ZN1DC2Ev(%class.D* {{[^,]*}} returned{{[^,]*}} %this, i8** noundef %vtt)
-// CHECKARM-LABEL: define{{.*}} %class.D* @_ZN1DC1Ev(%class.D* {{[^,]*}} returned{{[^,]*}} %this)
-// CHECKARM-LABEL: define{{.*}} %class.D* @_ZN1DD2Ev(%class.D* {{[^,]*}} returned{{[^,]*}} %this, i8** noundef %vtt)
-// CHECKARM-LABEL: define{{.*}} %class.D* @_ZN1DD1Ev(%class.D* {{[^,]*}} returned{{[^,]*}} %this)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.D* @_ZN1DC2Ev(%class.D* {{[^,]*}} returned{{[^,]*}} %this, i8** noundef %vtt)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.D* @_ZN1DC1Ev(%class.D* {{[^,]*}} returned{{[^,]*}} %this)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.D* @_ZN1DD2Ev(%class.D* {{[^,]*}} returned{{[^,]*}} %this, i8** noundef %vtt)
+// CHECKARM-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} %class.D* @_ZN1DD1Ev(%class.D* {{[^,]*}} returned{{[^,]*}} %this)
+
+// CHECKI686RET-LABEL: define{{.*}} %class.D* @_ZN1DC2Ev(%class.D* {{[^,]*}} %this, i8** noundef %vtt)
+// CHECKI686RET-LABEL: define{{.*}} %class.D* @_ZN1DC1Ev(%class.D* {{[^,]*}} %this)
+// CHECKI686RET-LABEL: define{{.*}} %class.D* @_ZN1DD2Ev(%class.D* {{[^,]*}} %this, i8** noundef %vtt)
+// CHECKI686RET-LABEL: define{{.*}} %class.D* @_ZN1DD1Ev(%class.D* {{[^,]*}} %this)
// CHECKIOS5-LABEL: define{{.*}} %class.D* @_ZN1DC2Ev(%class.D* {{[^,]*}} %this, i8** noundef %vtt)
// CHECKIOS5-LABEL: define{{.*}} %class.D* @_ZN1DC1Ev(%class.D* {{[^,]*}} %this)
@@ -147,17 +169,17 @@ void test_destructor() {
e2->~E();
}
-// CHECKARM-LABEL,CHECKFUCHSIA-LABEL: define{{.*}} void @_Z15test_destructorv()
+// CHECKARM-LABEL,CHECKFUCHSIA-LABEL,CHECKAARCH64RET-LABEL: define{{.*}} void @_Z15test_destructorv()
// Verify that virtual calls to destructors are not marked with a 'returned'
// this parameter at the call site...
-// CHECKARM: [[VFN:%.*]] = getelementptr inbounds %class.E* (%class.E*)*, %class.E* (%class.E*)**
-// CHECKARM: [[THUNK:%.*]] = load %class.E* (%class.E*)*, %class.E* (%class.E*)** [[VFN]]
+// CHECKARM,CHECKAARCH64RET: [[VFN:%.*]] = getelementptr inbounds %class.E* (%class.E*)*, %class.E* (%class.E*)**
+// CHECKARM,CHECKAARCH64RET: [[THUNK:%.*]] = load %class.E* (%class.E*)*, %class.E* (%class.E*)** [[VFN]]
// CHECKFUCHSIA: [[THUNK_I8:%.*]] = call i8* @llvm.load.relative.i32(i8* {{.*}}, i32 0)
// CHECKFUCHSIA: [[THUNK:%.*]] = bitcast i8* [[THUNK_I8]] to %class.E* (%class.E*)*
-// CHECKARM,CHECKFUCHSIA: call noundef %class.E* [[THUNK]](%class.E* {{[^,]*}} %
+// CHECKARM,CHECKFUCHSIA,CHECKAARCH64RET: call noundef %class.E* [[THUNK]](%class.E* {{[^,]*}} %
// ...but static calls create declarations with 'returned' this
-// CHECKARM,CHECKFUCHSIA: {{%.*}} = call noundef %class.E* @_ZN1ED1Ev(%class.E* {{[^,]*}} %
+// CHECKARM,CHECKFUCHSIA,CHECKAARCH64RET: {{%.*}} = call noundef %class.E* @_ZN1ED1Ev(%class.E* {{[^,]*}} %
-// CHECKARM,CHECKFUCHSIA: declare noundef %class.E* @_ZN1ED1Ev(%class.E* {{[^,]*}} returned{{[^,]*}})
+// CHECKARM,CHECKFUCHSIA,CHECKAARCH64RET: declare noundef %class.E* @_ZN1ED1Ev(%class.E* {{[^,]*}} returned{{[^,]*}})
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