Reland "[llvm][DebugInfo] DWARFv5: static data members declarations are DW_TAG_variable (#72234)"

This was reverted because it broke the OCaml LLVM bindings.
Relanding the original patch but without changing the C-API.
They'll continue to work just fine as they do today. If in the
future there is a need to pass a new tag to the C-API for creating
static members, then we'll make the change to the OCaml bindings
at that time.

Original commit message:
"""
This patch adds the LLVM-side infrastructure to implement DWARFv5 issue
161118.1: "DW_TAG for C++ static data members".

The clang-side of this patch will simply construct the DIDerivedType
with a different DW_TAG.
"""

4 files changed, 12 insertions, 12 deletions

diff --git a/llvm/lib/IR/DIBuilder.cpp b/llvm/lib/IR/DIBuilder.cpp
index 1ce8c17..58a7e07 100644
--- a/llvm/lib/IR/DIBuilder.cpp
+++ b/llvm/lib/IR/DIBuilder.cpp
@@ -405,12 +405,11 @@ DIDerivedType *
 DIBuilder::createStaticMemberType(DIScope *Scope, StringRef Name, DIFile *File,
                                   unsigned LineNumber, DIType *Ty,
                                   DINode::DIFlags Flags, llvm::Constant *Val,
-                                  uint32_t AlignInBits) {
+                                  unsigned Tag, uint32_t AlignInBits) {
   Flags |= DINode::FlagStaticMember;
-  return DIDerivedType::get(VMContext, dwarf::DW_TAG_member, Name, File,
-                            LineNumber, getNonCompileUnitScope(Scope), Ty, 0,
-                            AlignInBits, 0, std::nullopt, Flags,
-                            getConstantOrNull(Val));
+  return DIDerivedType::get(VMContext, Tag, Name, File, LineNumber,
+                            getNonCompileUnitScope(Scope), Ty, 0, AlignInBits,
+                            0, std::nullopt, Flags, getConstantOrNull(Val));
 }
 
 DIDerivedType *
diff --git a/llvm/lib/IR/DebugInfo.cpp b/llvm/lib/IR/DebugInfo.cpp
index 390a27c..bb6d6126 100644
--- a/llvm/lib/IR/DebugInfo.cpp
+++ b/llvm/lib/IR/DebugInfo.cpp
@@ -1315,17 +1315,15 @@ LLVMDIBuilderCreateUnspecifiedType(LLVMDIBuilderRef Builder, const char *Name,
   return wrap(unwrap(Builder)->createUnspecifiedType({Name, NameLen}));
 }
 
-LLVMMetadataRef
-LLVMDIBuilderCreateStaticMemberType(
+LLVMMetadataRef LLVMDIBuilderCreateStaticMemberType(
     LLVMDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
     size_t NameLen, LLVMMetadataRef File, unsigned LineNumber,
     LLVMMetadataRef Type, LLVMDIFlags Flags, LLVMValueRef ConstantVal,
     uint32_t AlignInBits) {
   return wrap(unwrap(Builder)->createStaticMemberType(
-                  unwrapDI<DIScope>(Scope), {Name, NameLen},
-                  unwrapDI<DIFile>(File), LineNumber, unwrapDI<DIType>(Type),
-                  map_from_llvmDIFlags(Flags), unwrap<Constant>(ConstantVal),
-                  AlignInBits));
+      unwrapDI<DIScope>(Scope), {Name, NameLen}, unwrapDI<DIFile>(File),
+      LineNumber, unwrapDI<DIType>(Type), map_from_llvmDIFlags(Flags),
+      unwrap<Constant>(ConstantVal), DW_TAG_member, AlignInBits));
 }
 
 LLVMMetadataRef
diff --git a/llvm/lib/IR/DebugInfoMetadata.cpp b/llvm/lib/IR/DebugInfoMetadata.cpp
index 0e14ec9..943826c 100644
--- a/llvm/lib/IR/DebugInfoMetadata.cpp
+++ b/llvm/lib/IR/DebugInfoMetadata.cpp
@@ -711,7 +711,9 @@ Constant *DIDerivedType::getStorageOffsetInBits() const {
 }
 
 Constant *DIDerivedType::getConstant() const {
-  assert(getTag() == dwarf::DW_TAG_member && isStaticMember());
+  assert((getTag() == dwarf::DW_TAG_member ||
+          getTag() == dwarf::DW_TAG_variable) &&
+         isStaticMember());
   if (auto *C = cast_or_null<ConstantAsMetadata>(getExtraData()))
     return C->getValue();
   return nullptr;
diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp
index b1d1075..25981d8 100644
--- a/llvm/lib/IR/Verifier.cpp
+++ b/llvm/lib/IR/Verifier.cpp
@@ -1172,6 +1172,7 @@ void Verifier::visitDIDerivedType(const DIDerivedType &N) {
               N.getTag() == dwarf::DW_TAG_restrict_type ||
               N.getTag() == dwarf::DW_TAG_atomic_type ||
               N.getTag() == dwarf::DW_TAG_member ||
+              (N.getTag() == dwarf::DW_TAG_variable && N.isStaticMember()) ||
               N.getTag() == dwarf::DW_TAG_inheritance ||
               N.getTag() == dwarf::DW_TAG_friend ||
               N.getTag() == dwarf::DW_TAG_set_type,