[clang-cl] Don't add implicit NoBuiltinAttr to deleted or defaulted functions

[VScigolevs]

In Clang #pragma function is implemented by adding an implicit NoBuiltin Attribute to all function definitions after the pragma. This (wrongly) includes also defaulted or deleted functions, which results in the error, shown in #116256.

As this attribute has no effect on the deleted or defaulted functions, this commit fixes the previously mentioned issue by simply not adding the attribute in such cases.

Fixes #116256

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[llvmbot]

@llvm/pr-subscribers-clang

Author: None (VScigolevs)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/119719.diff

2 Files Affected:

• (modified) clang/lib/Sema/SemaAttr.cpp (+2)
• (added) clang/test/SemaCXX/msvc-pragma-function-no-builtin-attr.cpp (+32)

diff --git a/clang/lib/Sema/SemaAttr.cpp b/clang/lib/Sema/SemaAttr.cpp
index 479f47962a7c3d..44485e71d57a01 100644
--- a/clang/lib/Sema/SemaAttr.cpp
+++ b/clang/lib/Sema/SemaAttr.cpp
@@ -1310,6 +1310,8 @@ void Sema::AddOptnoneAttributeIfNoConflicts(FunctionDecl *FD,
 }
 
 void Sema::AddImplicitMSFunctionNoBuiltinAttr(FunctionDecl *FD) {
+  if (FD->isDeleted() || FD->isDefaulted())
+    return;
   SmallVector<StringRef> V(MSFunctionNoBuiltins.begin(),
                            MSFunctionNoBuiltins.end());
   if (!MSFunctionNoBuiltins.empty())
diff --git a/clang/test/SemaCXX/msvc-pragma-function-no-builtin-attr.cpp b/clang/test/SemaCXX/msvc-pragma-function-no-builtin-attr.cpp
new file mode 100644
index 00000000000000..cd2ac7d1edbefb
--- /dev/null
+++ b/clang/test/SemaCXX/msvc-pragma-function-no-builtin-attr.cpp
@@ -0,0 +1,32 @@
+// RUN: %clang_cl -fms-compatibility -Xclang -ast-dump -fsyntax-only %s | FileCheck %s
+
+extern "C" __inline float __cdecl fabsf(  float _X);
+// CHECK: FunctionDecl {{.*}} fabsf
+#pragma function(fabsf)
+  __inline float __cdecl fabsf(  float _X)
+{
+    return 0;
+}
+// CHECK: FunctionDecl {{.*}} fabsf
+// CHECK: NoBuiltinAttr {{.*}} <<invalid sloc>> Implicit fabsf
+
+int bar() {
+  return 0;
+}
+// CHECK: FunctionDecl {{.*}} bar
+// CHECK: NoBuiltinAttr {{.*}} <<invalid sloc>> Implicit fabsf
+
+struct A {
+    int foo() = delete;
+    // CHECK: CXXMethodDecl {{.*}} foo 'int ()' delete
+    // CHECK-NOT: NoBuiltinAttr
+    A() = default;
+    // CHECK: CXXConstructorDecl {{.*}} A 'void ()' default
+    // CHECK-NOT: NoBuiltinAttr
+};
+
+int main() {
+    return 0;
+}
+// CHECK: FunctionDecl {{.*}} main
+// CHECK: NoBuiltinAttr {{.*}} <<invalid sloc>> Implicit fabsf

[cor3ntin]

Can you edit the description to explain the reason for that change? Thanks

[VScigolevs]

I don't have write access. Please merge on my behalf

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[VScigolevs]

I'm aware of the test failure, and know how to fix it. Will create a PR soon

[EDIT:] PR: #119873

[mgorny]

This test is failing on x86: #119979