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Support __builtin_launder except in the case of -fstrict-vtable-pointers
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@ghehg
ghehg committed Nov 22, 2024
1 parent dbd3e03 commit 5707f02
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Showing 3 changed files with 338 additions and 2 deletions.
1 change: 1 addition & 0 deletions clang/include/clang/CIR/MissingFeatures.h
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Original file line number Diff line number Diff line change
Expand Up @@ -230,6 +230,7 @@ struct MissingFeatures {
static bool emitEmptyRecordCheck() { return false; }
static bool isPPC_FP128Ty() { return false; }
static bool emitBinaryAtomicPostHasInvert() { return false; }
static bool createLaunderInvariantGroup() { return false; }

// Inline assembly
static bool asmGoto() { return false; }
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49 changes: 47 additions & 2 deletions clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -330,6 +330,43 @@ static mlir::Value MakeAtomicCmpXchgValue(CIRGenFunction &cgf,
return returnBool ? op.getResult(1) : op.getResult(0);
}

static bool
typeRequiresBuiltinLaunderImp(const ASTContext &ctx, QualType ty,
llvm::SmallPtrSetImpl<const Decl *> &seen) {
if (const auto *arr = ctx.getAsArrayType(ty))
ty = ctx.getBaseElementType(arr);

const auto *record = ty->getAsCXXRecordDecl();
if (!record)
return false;

// We've already checked this type, or are in the process of checking it.
if (!seen.insert(record).second)
return false;

assert(record->hasDefinition() &&
"Incomplete types should already be diagnosed");

if (record->isDynamicClass())
return true;

for (FieldDecl *fld : record->fields()) {
if (typeRequiresBuiltinLaunderImp(ctx, fld->getType(), seen))
return true;
}
return false;
}

/// Determine if the specified type requires laundering by checking if it is a
/// dynamic class type or contains a subobject which is a dynamic class type.
static bool typeRequiresBuiltinLaunder(clang::CIRGen::CIRGenModule &cgm,
QualType ty) {
if (!cgm.getCodeGenOpts().StrictVTablePointers)
return false;
llvm::SmallPtrSet<const Decl *, 16> seen;
return typeRequiresBuiltinLaunderImp(cgm.getASTContext(), ty, seen);
}

RValue CIRGenFunction::emitRotate(const CallExpr *E, bool IsRotateRight) {
auto src = emitScalarExpr(E->getArg(0));
auto shiftAmt = emitScalarExpr(E->getArg(1));
Expand Down Expand Up @@ -1622,8 +1659,16 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
llvm_unreachable("BI__builtin_setjmp NYI");
case Builtin::BI__builtin_longjmp:
llvm_unreachable("BI__builtin_longjmp NYI");
case Builtin::BI__builtin_launder:
llvm_unreachable("BI__builtin_launder NYI");
case Builtin::BI__builtin_launder: {
const clang::Expr *arg = E->getArg(0);
clang::QualType argTy = arg->getType()->getPointeeType();
mlir::Value ptr = emitScalarExpr(arg);
if (typeRequiresBuiltinLaunder(CGM, argTy)) {
assert(!MissingFeatures::createLaunderInvariantGroup());
llvm_unreachable(" launder.invariant.group NYI ");
}
return RValue::get(ptr);
}

case Builtin::BI__sync_fetch_and_add:
case Builtin::BI__sync_fetch_and_sub:
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290 changes: 290 additions & 0 deletions clang/test/CIR/CodeGen/builtins.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -105,3 +105,293 @@ extern "C" void *test_return_address(void) {
// LLVM-LABEL: @test_return_address
// LLVM: {{%.*}} = call ptr @llvm.returnaddress(i32 1)
}


// Following block of tests are for __builtin_launder
// FIXME: Once we fully __builtin_launder by allowing -fstrict-vtable-pointers,
// we should move following block of tests to a separate file.
namespace launder_test {
//===----------------------------------------------------------------------===//
// Positive Cases
//===----------------------------------------------------------------------===//

struct TestVirtualFn {
virtual void foo() {}
};

// CIR-LABEL: test_builtin_launder_virtual_fn
// LLVM: define{{.*}} void @test_builtin_launder_virtual_fn(ptr [[P:%.*]])
extern "C" void test_builtin_launder_virtual_fn(TestVirtualFn *p) {
// CIR: cir.return

// LLVM: store ptr [[P]], ptr [[P_ADDR:%.*]], align 8
// LLVM-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P_ADDR]], align 8
// LLVM-NEXT: store ptr [[TMP0]], ptr {{%.*}}
// LLVM-NEXT: ret void
TestVirtualFn *d = __builtin_launder(p);
}

struct TestPolyBase : TestVirtualFn {
};

// CIR-LABEL: test_builtin_launder_poly_base
// LLVM: define{{.*}} void @test_builtin_launder_poly_base(ptr [[P:%.*]])
extern "C" void test_builtin_launder_poly_base(TestPolyBase *p) {
// CIR: cir.return

// LLVM: store ptr [[P]], ptr [[P_ADDR:%.*]], align 8
// LLVM-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P_ADDR]], align 8
// LLVM-NEXT: store ptr [[TMP0]], ptr {{%.*}}
// LLVM-NEXT: ret void
TestPolyBase *d = __builtin_launder(p);
}

struct TestBase {};
struct TestVirtualBase : virtual TestBase {};

// CIR-LABEL: test_builtin_launder_virtual_base
// LLVM: define{{.*}} void @test_builtin_launder_virtual_base(ptr [[P:%.*]])
extern "C" void test_builtin_launder_virtual_base(TestVirtualBase *p) {
TestVirtualBase *d = __builtin_launder(p);

// CIR: cir.return

// LLVM: store ptr [[P]], ptr [[P_ADDR:%.*]], align 8
// LLVM-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P_ADDR]], align 8
// LLVM-NEXT: store ptr [[TMP0]], ptr {{%.*}}
// LLVM-NEXT: ret void
}

//===----------------------------------------------------------------------===//
// Negative Cases
//===----------------------------------------------------------------------===//

// CIR-LABEL: test_builtin_launder_ommitted_one
// LLVM: define{{.*}} void @test_builtin_launder_ommitted_one(ptr [[P:%.*]])
extern "C" void test_builtin_launder_ommitted_one(int *p) {
int *d = __builtin_launder(p);

// CIR: cir.return

// LLVM-NEXT: [[P_ADDR:%.*]] = alloca ptr, i64 1, align 8
// LLVM-NEXT: [[D:%.*]] = alloca ptr, i64 1, align 8
// LLVM: store ptr [[P]], ptr [[P_ADDR:%.*]], align 8
// LLVM-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P_ADDR]], align 8
// LLVM-NEXT: store ptr [[TMP0]], ptr [[D]]
// LLVM-NEXT: ret void
}

struct TestNoInvariant {
int x;
};

// CIR-LABEL: test_builtin_launder_ommitted_two
// LLVM: define{{.*}} void @test_builtin_launder_ommitted_two(ptr [[P:%.*]])
extern "C" void test_builtin_launder_ommitted_two(TestNoInvariant *p) {
TestNoInvariant *d = __builtin_launder(p);
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM-NEXT: [[P_ADDR:%.*]] = alloca ptr, i64 1, align 8
// LLVM-NEXT: [[D:%.*]] = alloca ptr, i64 1, align 8
// LLVM: store ptr [[P]], ptr [[P_ADDR:%.*]], align 8
// LLVM-NEXT: [[TMP0:%.*]] = load ptr, ptr [[P_ADDR]], align 8
// LLVM-NEXT: store ptr [[TMP0]], ptr [[D]]
// LLVM-NEXT: ret void
}

struct TestVirtualMember {
TestVirtualFn member;
};

// CIR-LABEL: test_builtin_launder_virtual_member
// LLVM: define{{.*}} void @test_builtin_launder_virtual_member
extern "C" void test_builtin_launder_virtual_member(TestVirtualMember *p) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
TestVirtualMember *d = __builtin_launder(p);
}

struct TestVirtualMemberDepth2 {
TestVirtualMember member;
};

// CIR-LABEL: test_builtin_launder_virtual_member_depth_2
// LLVM: define{{.*}} void @test_builtin_launder_virtual_member_depth_2
extern "C" void test_builtin_launder_virtual_member_depth_2(TestVirtualMemberDepth2 *p) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
TestVirtualMemberDepth2 *d = __builtin_launder(p);
}

struct TestVirtualReferenceMember {
TestVirtualFn &member;
};

// CIR-LABEL: test_builtin_launder_virtual_reference_member
// LLVM: define{{.*}} void @test_builtin_launder_virtual_reference_member
extern "C" void test_builtin_launder_virtual_reference_member(TestVirtualReferenceMember *p) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
TestVirtualReferenceMember *d = __builtin_launder(p);
}

struct TestRecursiveMember {
TestRecursiveMember() : member(*this) {}
TestRecursiveMember &member;
};

// CIR-LABEL: test_builtin_launder_recursive_member
// LLVM: define{{.*}} void @test_builtin_launder_recursive_member
extern "C" void test_builtin_launder_recursive_member(TestRecursiveMember *p) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
TestRecursiveMember *d = __builtin_launder(p);
}

struct TestVirtualRecursiveMember {
TestVirtualRecursiveMember() : member(*this) {}
TestVirtualRecursiveMember &member;
virtual void foo();
};

// CIR-LABEL: test_builtin_launder_virtual_recursive_member
// LLVM: define{{.*}} void @test_builtin_launder_virtual_recursive_member
extern "C" void test_builtin_launder_virtual_recursive_member(TestVirtualRecursiveMember *p) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
TestVirtualRecursiveMember *d = __builtin_launder(p);
}

// CIR-LABEL: test_builtin_launder_array
// LLVM: define{{.*}} void @test_builtin_launder_array
extern "C" void test_builtin_launder_array(TestVirtualFn (&Arr)[5]) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
TestVirtualFn *d = __builtin_launder(Arr);
}

// CIR-LABEL: test_builtin_launder_array_nested
// LLVM: define{{.*}} void @test_builtin_launder_array_nested
extern "C" void test_builtin_launder_array_nested(TestVirtualFn (&Arr)[5][2]) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
using RetTy = TestVirtualFn(*)[2];
RetTy d = __builtin_launder(Arr);
}

// CIR-LABEL: test_builtin_launder_array_no_invariant
// LLVM: define{{.*}} void @test_builtin_launder_array_no_invariant
extern "C" void test_builtin_launder_array_no_invariant(TestNoInvariant (&Arr)[5]) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
TestNoInvariant *d = __builtin_launder(Arr);
}

// CIR-LABEL: test_builtin_launder_array_nested_no_invariant
// LLVM: define{{.*}} void @test_builtin_launder_array_nested_no_invariant
extern "C" void test_builtin_launder_array_nested_no_invariant(TestNoInvariant (&Arr)[5][2]) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
using RetTy = TestNoInvariant(*)[2];
RetTy d = __builtin_launder(Arr);
}

template <class Member>
struct WithMember {
Member mem;
};

template struct WithMember<TestVirtualFn[5]>;

// CIR-LABEL: test_builtin_launder_member_array
// LLVM: define{{.*}} void @test_builtin_launder_member_array
extern "C" void test_builtin_launder_member_array(WithMember<TestVirtualFn[5]> *p) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
auto *d = __builtin_launder(p);
}

template struct WithMember<TestVirtualFn[5][2]>;

// CIR-LABEL: test_builtin_launder_member_array_nested
// LLVM: define{{.*}} void @test_builtin_launder_member_array_nested
extern "C" void test_builtin_launder_member_array_nested(WithMember<TestVirtualFn[5][2]> *p) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
auto *d = __builtin_launder(p);
}

template struct WithMember<TestNoInvariant[5]>;

// CIR-LABEL: test_builtin_launder_member_array_no_invariant
// LLVM: define{{.*}} void @test_builtin_launder_member_array_no_invariant
extern "C" void test_builtin_launder_member_array_no_invariant(WithMember<TestNoInvariant[5]> *p) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
auto *d = __builtin_launder(p);
}

template struct WithMember<TestNoInvariant[5][2]>;

// CIR-LABEL: test_builtin_launder_member_array_nested_no_invariant
// LLVM: define{{.*}} void @test_builtin_launder_member_array_nested_no_invariant
extern "C" void test_builtin_launder_member_array_nested_no_invariant(WithMember<TestNoInvariant[5][2]> *p) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
auto *d = __builtin_launder(p);
}

template <class T>
struct WithBase : T {};

template struct WithBase<TestNoInvariant>;

// CIR-LABEL: test_builtin_launder_base_no_invariant
// LLVM: define{{.*}} void @test_builtin_launder_base_no_invariant
extern "C" void test_builtin_launder_base_no_invariant(WithBase<TestNoInvariant> *p) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
auto *d = __builtin_launder(p);
}

template struct WithBase<TestVirtualFn>;

// CIR-LABEL: test_builtin_launder_base
// LLVM: define{{.*}} void @test_builtin_launder_base
extern "C" void test_builtin_launder_base(WithBase<TestVirtualFn> *p) {
// CIR: cir.return

// LLVM-NOT: llvm.launder.invariant.group
// LLVM: ret void
auto *d = __builtin_launder(p);
}
}

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