release/20.x: [clang] Support member function poiners in Decl::getFunctionType() (#125077)

[llvmbot]

Backport 692c9b2

Requested by: @MacDue

[llvmbot]

@efriedma-quic What do you think about merging this PR to the release branch?

[llvmbot]

@llvm/pr-subscribers-clang

Author: None (llvmbot)

Changes

Backport 692c9b2

Requested by: @MacDue

---

Full diff: https://github.com/llvm/llvm-project/pull/125956.diff

6 Files Affected:

• (modified) clang/include/clang/AST/DeclBase.h (+5-2)
• (modified) clang/include/clang/Basic/Attr.td (+1-1)
• (modified) clang/lib/AST/DeclBase.cpp (+2)
• (modified) clang/test/AST/attr-print-emit.cpp (+5)
• (added) clang/test/CodeGen/AArch64/sme-attributes-member-function-pointer.cpp (+37)
• (added) clang/test/CodeGen/xfail-alloc-align-fn-pointers.cpp (+10)

diff --git a/clang/include/clang/AST/DeclBase.h b/clang/include/clang/AST/DeclBase.h
index 2c0c3a8dc2f9d5..3bb82c1572ef9c 100644
--- a/clang/include/clang/AST/DeclBase.h
+++ b/clang/include/clang/AST/DeclBase.h
@@ -1257,8 +1257,11 @@ class alignas(8) Decl {
   int64_t getID() const;
 
   /// Looks through the Decl's underlying type to extract a FunctionType
-  /// when possible. Will return null if the type underlying the Decl does not
-  /// have a FunctionType.
+  /// when possible. This includes direct FunctionDecls, along with various
+  /// function types and typedefs. This includes function pointers/references,
+  /// member function pointers, and optionally if \p BlocksToo is set
+  /// Objective-C block pointers. Returns nullptr if the type underlying the
+  /// Decl does not have a FunctionType.
   const FunctionType *getFunctionType(bool BlocksToo = true) const;
 
   // Looks through the Decl's underlying type to determine if it's a
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index f4ba2bc3c6de31..2a3a29bd2ee1cf 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -198,7 +198,7 @@ def OpenCLKernelFunction
 // inclusive nature of subject testing).
 def HasFunctionProto : SubsetSubject<DeclBase,
                                      [{(S->getFunctionType(true) != nullptr &&
-                              isa<FunctionProtoType>(S->getFunctionType())) ||
+                                       isa<FunctionProtoType>(S->getFunctionType())) ||
                                        isa<ObjCMethodDecl>(S) ||
                                        isa<BlockDecl>(S)}],
                                      "non-K&R-style functions">;
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index 8506b95f761fe5..adf6053392db37 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -1203,6 +1203,8 @@ const FunctionType *Decl::getFunctionType(bool BlocksToo) const {
 
   if (Ty->isFunctionPointerType())
     Ty = Ty->castAs<PointerType>()->getPointeeType();
+  else if (Ty->isMemberFunctionPointerType())
+    Ty = Ty->castAs<MemberPointerType>()->getPointeeType();
   else if (Ty->isFunctionReferenceType())
     Ty = Ty->castAs<ReferenceType>()->getPointeeType();
   else if (BlocksToo && Ty->isBlockPointerType())
diff --git a/clang/test/AST/attr-print-emit.cpp b/clang/test/AST/attr-print-emit.cpp
index a9bca6778d0f1a..77826f8f9af098 100644
--- a/clang/test/AST/attr-print-emit.cpp
+++ b/clang/test/AST/attr-print-emit.cpp
@@ -91,3 +91,8 @@ ANNOTATE_ATTR NONNULL_ATTR void fn_non_null_annotated_attr(int *) __attribute__(
 
 [[gnu::nonnull(1)]] [[gnu::always_inline]] void cxx11_attr(int*) ANNOTATE_ATTR;
 // CHECK: {{\[\[}}gnu::nonnull(1)]] {{\[\[}}gnu::always_inline]] void cxx11_attr(int *) __attribute__((annotate("Annotated")));
+
+struct Foo;
+
+// CHECK: void as_member_fn_ptr(int *(Foo::*member)(int) __attribute__((alloc_size(1))));
+void as_member_fn_ptr(int* (Foo::*member)(int)  __attribute__((alloc_size(1))));
diff --git a/clang/test/CodeGen/AArch64/sme-attributes-member-function-pointer.cpp b/clang/test/CodeGen/AArch64/sme-attributes-member-function-pointer.cpp
new file mode 100644
index 00000000000000..ee784c816a0606
--- /dev/null
+++ b/clang/test/CodeGen/AArch64/sme-attributes-member-function-pointer.cpp
@@ -0,0 +1,37 @@
+// RUN: %clang_cc1 -triple aarch64 -target-feature +sme -target-feature +sme2 -x c++ -std=c++20  -emit-llvm -o - %s | FileCheck %s --check-prefixes=CHECK
+
+struct TestStruct;
+
+__arm_new("za", "zt0") void test(TestStruct& TS,
+  void (TestStruct::*streaming_member_ptr)() __arm_streaming,
+  void (TestStruct::*streaming_compat_member)() __arm_streaming_compatible,
+  void (TestStruct::*arm_in_member)() __arm_in("za", "zt0"),
+  void (TestStruct::*arm_inout_member)() __arm_inout("za", "zt0"),
+  void (TestStruct::*arm_preserves_member)() __arm_preserves("za", "zt0"),
+  void (TestStruct::*arm_agnostic_member)() __arm_agnostic("sme_za_state")) {
+
+  // CHECK: call void %{{.*}} [[STREAMING_MEMBER_CALL_ATTRS:#.+]]
+  (TS.*streaming_member_ptr)();
+
+  // CHECK: call void %{{.*}} [[STREAMING_COMPAT_MEMBER_CALL_ATTRS:#.+]]
+  (TS.*streaming_compat_member)();
+
+  // CHECK: call void %{{.*}} [[ARM_IN_MEMBER_CALL_ATTRS:#.+]]
+  (TS.*arm_in_member)();
+
+  // CHECK: call void %{{.*}} [[ARM_INOUT_MEMBER_CALL_ATTRS:#.+]]
+  (TS.*arm_inout_member)();
+
+  // CHECK: call void %{{.*}} [[ARM_PRESERVES_MEMBER_CALL_ATTRS:#.+]]
+  (TS.*arm_preserves_member)();
+
+  // CHECK: call void %{{.*}} [[ARM_AGNOSTIC_MEMBER_CALL_ATTRS:#.+]]
+  (TS.*arm_agnostic_member)();
+}
+
+// CHECK: attributes [[STREAMING_MEMBER_CALL_ATTRS]] = { "aarch64_pstate_sm_enabled" }
+// CHECK: attributes [[STREAMING_COMPAT_MEMBER_CALL_ATTRS]] = { "aarch64_pstate_sm_compatible" }
+// CHECK: attributes [[ARM_IN_MEMBER_CALL_ATTRS]] = { "aarch64_in_za" "aarch64_in_zt0" }
+// CHECK: attributes [[ARM_INOUT_MEMBER_CALL_ATTRS]] = { "aarch64_inout_za" "aarch64_inout_zt0" }
+// CHECK: attributes [[ARM_PRESERVES_MEMBER_CALL_ATTRS]] = { "aarch64_preserves_za" "aarch64_preserves_zt0" }
+// CHECK: attributes [[ARM_AGNOSTIC_MEMBER_CALL_ATTRS]] = { "aarch64_za_state_agnostic" }
diff --git a/clang/test/CodeGen/xfail-alloc-align-fn-pointers.cpp b/clang/test/CodeGen/xfail-alloc-align-fn-pointers.cpp
new file mode 100644
index 00000000000000..80067500284b1e
--- /dev/null
+++ b/clang/test/CodeGen/xfail-alloc-align-fn-pointers.cpp
@@ -0,0 +1,10 @@
+
+// RUN: %clang_cc1 %s
+
+// FIXME: These should not crash!
+// XFAIL: *
+
+void aa_fn_ptr(char* (*member)(char*)  __attribute__((alloc_align(1))));
+
+struct Test;
+void aa_member_fn_ptr(char* (Test::*member)(char*)  __attribute__((alloc_align(1))));

[efriedma-quic]

LGTM. This doesn't seem like a high priority to backport, but I guess it's safe enough for this point in the process.

[github-actions]

@MacDue (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.