[CIR] Support more declarations without any codegen #151076
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mmha
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lanza and
xlauko
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This patch adds or completes support for a couple of top level declaration types that don't emit any code: Most notably these include Concepts, static_assert and type aliases.
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@llvm/pr-subscribers-clang @llvm/pr-subscribers-clangir Author: Morris Hafner (mmha) ChangesThis patch adds or completes support for a couple of top level declaration types that don't emit any code: Most notably these include Concepts, static_assert and type aliases. Full diff: https://github.com/llvm/llvm-project/pull/151076.diff 2 Files Affected:
diff --git a/clang/lib/CIR/CodeGen/CIRGenModule.cpp b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
index 350270518156e..6f32c9e2e2f8d 100644
--- a/clang/lib/CIR/CodeGen/CIRGenModule.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenModule.cpp
@@ -1267,8 +1267,13 @@ void CIRGenModule::emitTopLevelDecl(Decl *decl) {
break;
// No code generation needed.
- case Decl::UsingShadow:
+ case Decl::ClassTemplate:
+ case Decl::Concept:
case Decl::Empty:
+ case Decl::FunctionTemplate:
+ case Decl::StaticAssert:
+ case Decl::TypeAliasTemplate:
+ case Decl::UsingShadow:
break;
case Decl::CXXConstructor:
diff --git a/clang/test/CIR/CodeGen/empty.cpp b/clang/test/CIR/CodeGen/empty.cpp
new file mode 100644
index 0000000000000..7e61f4b1211a3
--- /dev/null
+++ b/clang/test/CIR/CodeGen/empty.cpp
@@ -0,0 +1,27 @@
+// RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s --check-prefix=CIR
+
+// These declarations shouldn't emit any code. Therefore the module is expected to be empty.
+
+template<typename T>
+concept some_concept = true;
+
+template<some_concept T>
+class class_template {};
+
+; // Empty declaration
+
+template<typename T>
+void function_template();
+
+static_assert(true, "top level static assert");
+
+template<typename T>
+using type_alias = T;
+
+namespace N {
+ using ::class_template; // UsingShadow
+}
+
+// CIR: module {{.*}} {
+// CIR-NEXT: }
\ No newline at end of file
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| case Decl::Empty: | ||
| case Decl::FunctionTemplate: | ||
| case Decl::StaticAssert: | ||
| case Decl::TypeAliasTemplate: |
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You can add Decl::VarTemplate, Decl::VarTemplatePartialSpecialization, Decl::Block, Decl::Binding to be complete and on par with classic codegen.
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Variable templates are covered in #151066.
I tinkered with Blocks a little bit and it seems like it's not possible to create a BlockDecl without a BlockExpr which requires codegen that's not implemented, yet. Likewise, a BindingDecl can only show up with a DecompositionDecl and while #151073 implements them on a function scope level we don't support them on in namespace scopes, yet. So these DeclKinds would be dead code which is why I didn't add them in this PR.
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This patch adds or completes support for a couple of top level declaration types that don't emit any code: Most notably these include Concepts, static_assert and type aliases.