[Clang] Added check for unexpanded pack in attribute [[assume]]

[azmat-y]

Added a check for unexpanded parameter pack in attribute [[assume]]. Tested it with expected-error statements from clang fronted. This fixes #91232. @Sirraide

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[llvmbot]

@llvm/pr-subscribers-clang

Author: Azmat Yusuf (azmat-y)

Changes

Added a check for unexpanded parameter pack in attribute [[assume]]. Tested it with expected-error statements from clang fronted. This fixes #91232. @Sirraide

---

Full diff: https://github.com/llvm/llvm-project/pull/91893.diff

2 Files Affected:

• (modified) clang/lib/Sema/SemaStmtAttr.cpp (+5)
• (modified) clang/test/SemaCXX/cxx23-assume.cpp (+5)

diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
index 1c84830b6ddd2..36f8ecadcfab7 100644
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -670,6 +670,11 @@ ExprResult Sema::ActOnCXXAssumeAttr(Stmt *St, const ParsedAttr &A,
   }
 
   auto *Assumption = A.getArgAsExpr(0);
+
+  if (DiagnoseUnexpandedParameterPack(Assumption)) {
+    return ExprError();
+  }
+
   if (Assumption->getDependence() == ExprDependence::None) {
     ExprResult Res = BuildCXXAssumeExpr(Assumption, A.getAttrName(), Range);
     if (Res.isInvalid())
diff --git a/clang/test/SemaCXX/cxx23-assume.cpp b/clang/test/SemaCXX/cxx23-assume.cpp
index 8676970de14f6..e67d72ae0a995 100644
--- a/clang/test/SemaCXX/cxx23-assume.cpp
+++ b/clang/test/SemaCXX/cxx23-assume.cpp
@@ -138,3 +138,8 @@ constexpr int foo() {
 }
 
 static_assert(foo() == 0);
+
+template <bool ...val>
+void f() {
+    [[assume(val)]]; // expected-error {{expression contains unexpanded parameter pack}}
+}

[cor3ntin]

LGTM!
Thanks for working on this

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@azmat-y Congratulations on having your first Pull Request (PR) merged into the LLVM Project!

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[azmat-y]

It was a pleasure working on this.

I have received two emails from llvm build bot regarding failed builds, though the commit shows 8 build fails. How to go about investigating the cause of failures? Can you give me some pointers regarding this. And do the failures means this patch will need to be reverted?

[Sirraide]

I have received two emails from llvm build bot regarding failed builds, though the commit shows 8 build fails.

That need not be because of this pr specifically; it may just be that someone else did something that caused the build to fail, and the commit for this pr just happened to be among the commits that was tested. Can you put the buildbot link here so we can take a look at it?

[azmat-y]

Here are the builds

Mentioned in emails
clang-aarch64-sve-vls
clang-aarch64-sve-vla-2stage

Others
arc-builder
bolt-x86_64-ubuntu-clang
clang-with-lto-ubuntu
clang-with-thin-lto-ubuntu
clang-x64-windows-msvc
lldb-aarch64-windows

[Sirraide]

Here are the builds

Mentioned in emails clang-aarch64-sve-vls clang-aarch64-sve-vla-2stage

Others arc-builder bolt-x86_64-ubuntu-clang clang-with-lto-ubuntu clang-with-thin-lto-ubuntu clang-x64-windows-msvc lldb-aarch64-windows

That’s an MLIR test which is entirely unrelated to any of this here, so you should be able to ignore that.

[azmat-y]

Thanks for confirming and also thanks for your help.