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[CIR] Add support for C++ initializer lists #150681

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Merged
merged 1 commit into from
Jul 25, 2025
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[CIR] Add support for C++ initializer lists #150681

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92 changes: 90 additions & 2 deletions clang/lib/CIR/CodeGen/CIRGenExprAggregate.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -357,10 +357,98 @@ void AggExprEmitter::visitCXXParenListOrInitListExpr(
emitArrayInit(dest.getAddress(), arrayTy, e->getType(), e, args,
arrayFiller);
return;
} else if (e->getType()->isVariableArrayType()) {
cgf.cgm.errorNYI(e->getSourceRange(),
"visitCXXParenListOrInitListExpr variable array type");
return;
}

if (e->getType()->isArrayType()) {
cgf.cgm.errorNYI(e->getSourceRange(),
"visitCXXParenListOrInitListExpr array type");
return;
}

assert(e->getType()->isRecordType() && "Only support structs/unions here!");

// Do struct initialization; this code just sets each individual member
// to the approprate value. This makes bitfield support automatic;
// the disadvantage is that the generated code is more difficult for
// the optimizer, especially with bitfields.
unsigned numInitElements = args.size();
RecordDecl *record = e->getType()->castAs<RecordType>()->getDecl();

// We'll need to enter cleanup scopes in case any of the element
// initializers throws an exception.
assert(!cir::MissingFeatures::requiresCleanups());

unsigned curInitIndex = 0;

// Emit initialization of base classes.
if (auto *cxxrd = dyn_cast<CXXRecordDecl>(record)) {
assert(numInitElements >= cxxrd->getNumBases() &&
"missing initializer for base class");
if (cxxrd->getNumBases() > 0) {
cgf.cgm.errorNYI(e->getSourceRange(),
"visitCXXParenListOrInitListExpr base class init");
return;
}
}

LValue destLV = cgf.makeAddrLValue(dest.getAddress(), e->getType());

if (record->isUnion()) {
cgf.cgm.errorNYI(e->getSourceRange(),
"visitCXXParenListOrInitListExpr union type");
return;
}

cgf.cgm.errorNYI(
"visitCXXParenListOrInitListExpr Record or VariableSizeArray type");
// Here we iterate over the fields; this makes it simpler to both
// default-initialize fields and skip over unnamed fields.
for (const FieldDecl *field : record->fields()) {
// We're done once we hit the flexible array member.
if (field->getType()->isIncompleteArrayType())
break;

// Always skip anonymous bitfields.
if (field->isUnnamedBitField())
continue;

// We're done if we reach the end of the explicit initializers, we
// have a zeroed object, and the rest of the fields are
// zero-initializable.
if (curInitIndex == numInitElements && dest.isZeroed() &&
cgf.getTypes().isZeroInitializable(e->getType()))
break;
LValue lv =
cgf.emitLValueForFieldInitialization(destLV, field, field->getName());
// We never generate write-barriers for initialized fields.
assert(!cir::MissingFeatures::setNonGC());

if (curInitIndex < numInitElements) {
// Store the initializer into the field.
CIRGenFunction::SourceLocRAIIObject loc{
cgf, cgf.getLoc(record->getSourceRange())};
emitInitializationToLValue(args[curInitIndex++], lv);
} else {
// We're out of initializers; default-initialize to null
emitNullInitializationToLValue(cgf.getLoc(e->getSourceRange()), lv);
}

// Push a destructor if necessary.
// FIXME: if we have an array of structures, all explicitly
// initialized, we can end up pushing a linear number of cleanups.
if (QualType::DestructionKind dtorKind =
field->getType().isDestructedType()) {
cgf.cgm.errorNYI(e->getSourceRange(),
"visitCXXParenListOrInitListExpr destructor");
return;
}

// From classic codegen, maybe not useful for CIR:
// If the GEP didn't get used because of a dead zero init or something
// else, clean it up for -O0 builds and general tidiness.
}
}

// TODO(cir): This could be shared with classic codegen.
Expand Down
184 changes: 184 additions & 0 deletions clang/test/CIR/CodeGen/struct-init.cpp
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Original file line number Diff line number Diff line change
@@ -0,0 +1,184 @@
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
// RUN: FileCheck --check-prefix=CIR --input-file=%t.cir %s
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o %t-cir.ll
// RUN: FileCheck --check-prefix=LLVM --input-file=%t-cir.ll %s
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o %t.ll
// RUN: FileCheck --check-prefix=OGCG --input-file=%t.ll %s

struct S {
int a, b, c;
};

void init() {
S s1 = {1, 2, 3};
S s2 = {4, 5};
}

// CIR: cir.func{{.*}} @_Z4initv()
// CIR: %[[S1:.*]] = cir.alloca !rec_S, !cir.ptr<!rec_S>, ["s1", init]
// CIR: %[[S2:.*]] = cir.alloca !rec_S, !cir.ptr<!rec_S>, ["s2", init]
// CIR: %[[S1_A:.*]] = cir.get_member %[[S1]][0] {name = "a"}
// CIR: %[[ONE:.*]] = cir.const #cir.int<1>
// CIR: cir.store{{.*}} %[[ONE]], %[[S1_A]]
// CIR: %[[S1_B:.*]] = cir.get_member %[[S1]][1] {name = "b"}
// CIR: %[[TWO:.*]] = cir.const #cir.int<2>
// CIR: cir.store{{.*}} %[[TWO]], %[[S1_B]]
// CIR: %[[S1_C:.*]] = cir.get_member %[[S1]][2] {name = "c"}
// CIR: %[[THREE:.*]] = cir.const #cir.int<3>
// CIR: cir.store{{.*}} %[[THREE]], %[[S1_C]]
// CIR: %[[S2_A:.*]] = cir.get_member %[[S2]][0] {name = "a"}
// CIR: %[[FOUR:.*]] = cir.const #cir.int<4>
// CIR: cir.store{{.*}} %[[FOUR]], %[[S2_A]]
// CIR: %[[S2_B:.*]] = cir.get_member %[[S2]][1] {name = "b"}
// CIR: %[[FIVE:.*]] = cir.const #cir.int<5>
// CIR: cir.store{{.*}} %[[FIVE]], %[[S2_B]]
// CIR: %[[S2_C:.*]] = cir.get_member %[[S2]][2] {name = "c"}
// CIR: %[[ZERO:.*]] = cir.const #cir.int<0>
// CIR: cir.store{{.*}} %[[ZERO]], %[[S2_C]]
// CIR: cir.return

// LLVM: define{{.*}} void @_Z4initv()
// LLVM: %[[S1:.*]] = alloca %struct.S
// LLVM: %[[S2:.*]] = alloca %struct.S
// LLVM: %[[S1_A:.*]] = getelementptr %struct.S, ptr %[[S1]], i32 0, i32 0
// LLVM: store i32 1, ptr %[[S1_A]]
// LLVM: %[[S1_B:.*]] = getelementptr %struct.S, ptr %[[S1]], i32 0, i32 1
// LLVM: store i32 2, ptr %[[S1_B]]
// LLVM: %[[S1_C:.*]] = getelementptr %struct.S, ptr %[[S1]], i32 0, i32 2
// LLVM: store i32 3, ptr %[[S1_C]]
// LLVM: %[[S2_A:.*]] = getelementptr %struct.S, ptr %[[S2]], i32 0, i32 0
// LLVM: store i32 4, ptr %[[S2_A]]
// LLVM: %[[S2_B:.*]] = getelementptr %struct.S, ptr %[[S2]], i32 0, i32 1
// LLVM: store i32 5, ptr %[[S2_B]]
// LLVM: %[[S2_C:.*]] = getelementptr %struct.S, ptr %[[S2]], i32 0, i32 2
// LLVM: store i32 0, ptr %[[S2_C]]

// OGCG: @__const._Z4initv.s1 = private unnamed_addr constant %struct.S { i32 1, i32 2, i32 3 }
// OGCG: @__const._Z4initv.s2 = private unnamed_addr constant %struct.S { i32 4, i32 5, i32 0 }

// OGCG: define{{.*}} void @_Z4initv()
// OGCG: %[[S1:.*]] = alloca %struct.S
// OGCG: %[[S2:.*]] = alloca %struct.S
// OGCG: call void @llvm.memcpy.p0.p0.i64(ptr{{.*}} %[[S1]], ptr{{.*}} @__const._Z4initv.s1, i64 12, i1 false)
// OGCG: call void @llvm.memcpy.p0.p0.i64(ptr{{.*}} %[[S2]], ptr{{.*}} @__const._Z4initv.s2, i64 12, i1 false)

void init_var(int a, int b) {
S s = {a, b};
}

// CIR: cir.func{{.*}} @_Z8init_varii(%[[A_ARG:.*]]: !s32i {{.*}}, %[[B_ARG:.*]]: !s32i {{.*}})
// CIR: %[[A_PTR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["a", init]
// CIR: %[[B_PTR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["b", init]
// CIR: %[[S:.*]] = cir.alloca !rec_S, !cir.ptr<!rec_S>, ["s", init]
// CIR: cir.store{{.*}} %[[A_ARG]], %[[A_PTR]]
// CIR: cir.store{{.*}} %[[B_ARG]], %[[B_PTR]]
// CIR: %[[S_A:.*]] = cir.get_member %[[S]][0] {name = "a"}
// CIR: %[[A:.*]] = cir.load{{.*}} %[[A_PTR]]
// CIR: cir.store{{.*}} %[[A]], %[[S_A]]
// CIR: %[[S_B:.*]] = cir.get_member %[[S]][1] {name = "b"}
// CIR: %[[B:.*]] = cir.load{{.*}} %[[B_PTR]]
// CIR: cir.store{{.*}} %[[B]], %[[S_B]]
// CIR: cir.return

// LLVM: define{{.*}} void @_Z8init_varii(i32 %[[A_ARG:.*]], i32 %[[B_ARG:.*]])
// LLVM: %[[A_PTR:.*]] = alloca i32
// LLVM: %[[B_PTR:.*]] = alloca i32
// LLVM: %[[S:.*]] = alloca %struct.S
// LLVM: store i32 %[[A_ARG]], ptr %[[A_PTR]]
// LLVM: store i32 %[[B_ARG]], ptr %[[B_PTR]]
// LLVM: %[[S_A:.*]] = getelementptr %struct.S, ptr %[[S]], i32 0, i32 0
// LLVM: %[[A:.*]] = load i32, ptr %[[A_PTR]]
// LLVM: store i32 %[[A]], ptr %[[S_A]]
// LLVM: %[[S_B:.*]] = getelementptr %struct.S, ptr %[[S]], i32 0, i32 1
// LLVM: %[[B:.*]] = load i32, ptr %[[B_PTR]]
// LLVM: store i32 %[[B]], ptr %[[S_B]]
// LLVM: ret void

// OGCG: define{{.*}} void @_Z8init_varii(i32 {{.*}} %[[A_ARG:.*]], i32 {{.*}} %[[B_ARG:.*]])
// OGCG: %[[A_PTR:.*]] = alloca i32
// OGCG: %[[B_PTR:.*]] = alloca i32
// OGCG: %[[S:.*]] = alloca %struct.S
// OGCG: store i32 %[[A_ARG]], ptr %[[A_PTR]]
// OGCG: store i32 %[[B_ARG]], ptr %[[B_PTR]]
// OGCG: %[[S_A:.*]] = getelementptr {{.*}} %struct.S, ptr %[[S]], i32 0, i32 0
// OGCG: %[[A:.*]] = load i32, ptr %[[A_PTR]]
// OGCG: store i32 %[[A]], ptr %[[S_A]]
// OGCG: %[[S_B:.*]] = getelementptr {{.*}} %struct.S, ptr %[[S]], i32 0, i32 1
// OGCG: %[[B:.*]] = load i32, ptr %[[B_PTR]]
// OGCG: store i32 %[[B]], ptr %[[S_B]]
// OGCG: %[[S_C:.*]] = getelementptr {{.*}} %struct.S, ptr %[[S]], i32 0, i32 2
// OGCG: store i32 0, ptr %[[S_C]]
// OGCG: ret void

void init_expr(int a, int b, int c) {
S s = {a + 1, b + 2, c + 3};
}

// CIR: cir.func{{.*}} @_Z9init_expriii(%[[A_ARG:.*]]: !s32i {{.*}}, %[[B_ARG:.*]]: !s32i {{.*}}, %[[C_ARG:.*]]: !s32i {{.*}})
// CIR: %[[A_PTR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["a", init]
// CIR: %[[B_PTR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["b", init]
// CIR: %[[C_PTR:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["c", init]
// CIR: %[[S:.*]] = cir.alloca !rec_S, !cir.ptr<!rec_S>, ["s", init]
// CIR: cir.store{{.*}} %[[A_ARG]], %[[A_PTR]]
// CIR: cir.store{{.*}} %[[B_ARG]], %[[B_PTR]]
// CIR: cir.store{{.*}} %[[C_ARG]], %[[C_PTR]]
// CIR: %[[S_A:.*]] = cir.get_member %[[S]][0] {name = "a"}
// CIR: %[[A:.*]] = cir.load{{.*}} %[[A_PTR]]
// CIR: %[[ONE:.*]] = cir.const #cir.int<1>
// CIR: %[[A_PLUS_ONE:.*]] = cir.binop(add, %[[A]], %[[ONE]])
// CIR: cir.store{{.*}} %[[A_PLUS_ONE]], %[[S_A]]
// CIR: %[[S_B:.*]] = cir.get_member %[[S]][1] {name = "b"}
// CIR: %[[B:.*]] = cir.load{{.*}} %[[B_PTR]]
// CIR: %[[TWO:.*]] = cir.const #cir.int<2>
// CIR: %[[B_PLUS_TWO:.*]] = cir.binop(add, %[[B]], %[[TWO]]) nsw : !s32i
// CIR: cir.store{{.*}} %[[B_PLUS_TWO]], %[[S_B]]
// CIR: %[[S_C:.*]] = cir.get_member %[[S]][2] {name = "c"}
// CIR: %[[C:.*]] = cir.load{{.*}} %[[C_PTR]]
// CIR: %[[THREE:.*]] = cir.const #cir.int<3>
// CIR: %[[C_PLUS_THREE:.*]] = cir.binop(add, %[[C]], %[[THREE]]) nsw : !s32i
// CIR: cir.store{{.*}} %[[C_PLUS_THREE]], %[[S_C]]
// CIR: cir.return

// LLVM: define{{.*}} void @_Z9init_expriii(i32 %[[A_ARG:.*]], i32 %[[B_ARG:.*]], i32 %[[C_ARG:.*]])
// LLVM: %[[A_PTR:.*]] = alloca i32
// LLVM: %[[B_PTR:.*]] = alloca i32
// LLVM: %[[C_PTR:.*]] = alloca i32
// LLVM: %[[S:.*]] = alloca %struct.S
// LLVM: store i32 %[[A_ARG]], ptr %[[A_PTR]]
// LLVM: store i32 %[[B_ARG]], ptr %[[B_PTR]]
// LLVM: store i32 %[[C_ARG]], ptr %[[C_PTR]]
// LLVM: %[[S_A:.*]] = getelementptr %struct.S, ptr %[[S]], i32 0, i32 0
// LLVM: %[[A:.*]] = load i32, ptr %[[A_PTR]]
// LLVM: %[[A_PLUS_ONE:.*]] = add nsw i32 %[[A]], 1
// LLVM: store i32 %[[A_PLUS_ONE]], ptr %[[S_A]]
// LLVM: %[[S_B:.*]] = getelementptr %struct.S, ptr %[[S]], i32 0, i32 1
// LLVM: %[[B:.*]] = load i32, ptr %[[B_PTR]]
// LLVM: %[[B_PLUS_TWO:.*]] = add nsw i32 %[[B]], 2
// LLVM: store i32 %[[B_PLUS_TWO]], ptr %[[S_B]]
// LLVM: %[[S_C:.*]] = getelementptr %struct.S, ptr %[[S]], i32 0, i32 2
// LLVM: %[[C:.*]] = load i32, ptr %[[C_PTR]]
// LLVM: %[[C_PLUS_THREE:.*]] = add nsw i32 %[[C]], 3
// LLVM: store i32 %[[C_PLUS_THREE]], ptr %[[S_C]]
// LLVM: ret void

// OGCG: define{{.*}} void @_Z9init_expriii(i32 {{.*}} %[[A_ARG:.*]], i32 {{.*}} %[[B_ARG:.*]], i32 {{.*}} %[[C_ARG:.*]])
// OGCG: %[[A_PTR:.*]] = alloca i32
// OGCG: %[[B_PTR:.*]] = alloca i32
// OGCG: %[[C_PTR:.*]] = alloca i32
// OGCG: %[[S:.*]] = alloca %struct.S
// OGCG: store i32 %[[A_ARG]], ptr %[[A_PTR]]
// OGCG: store i32 %[[B_ARG]], ptr %[[B_PTR]]
// OGCG: store i32 %[[C_ARG]], ptr %[[C_PTR]]
// OGCG: %[[S_A:.*]] = getelementptr {{.*}} %struct.S, ptr %[[S]], i32 0, i32 0
// OGCG: %[[A:.*]] = load i32, ptr %[[A_PTR]]
// OGCG: %[[A_PLUS_ONE:.*]] = add nsw i32 %[[A]], 1
// OGCG: store i32 %[[A_PLUS_ONE]], ptr %[[S_A]]
// OGCG: %[[S_B:.*]] = getelementptr {{.*}} %struct.S, ptr %[[S]], i32 0, i32 1
// OGCG: %[[B:.*]] = load i32, ptr %[[B_PTR]]
// OGCG: %[[B_PLUS_TWO:.*]] = add nsw i32 %[[B]], 2
// OGCG: store i32 %[[B_PLUS_TWO]], ptr %[[S_B]]
// OGCG: %[[S_C:.*]] = getelementptr {{.*}} %struct.S, ptr %[[S]], i32 0, i32 2
// OGCG: %[[C:.*]] = load i32, ptr %[[C_PTR]]
// OGCG: %[[C_PLUS_THREE:.*]] = add nsw i32 %[[C]], 3
// OGCG: store i32 %[[C_PLUS_THREE]], ptr %[[S_C]]
// OGCG: ret void