[llvm][DebugInfo][clang] Finalize all declaration subprograms in DIBuilder::finalize() (llvm#139914)

DIBuilder began tracking definition subprograms and finalizing them in
`DIBuilder::finalize()` in eb1bb4e.
Currently, `finalizeSubprogram()` attaches local variables, imported
entities, and labels to the `retainedNodes:` field of a corresponding
subprogram.

After 75819ae, the definition and some declaration subprograms are
finalized in `DIBuilder::finalize()`:
`AllSubprograms` holds references to definition subprograms.
`AllRetainTypes` holds references to declaration subprograms.
For DISubprogram elements of both variables, `finalizeSubprogram()` was
called there.

However, `retainTypes()` is not necessarily called for every declaration
subprogram (as in 40a3fcb).

DIBuilder clients may also want to attach DILocalVariables to
declaration subprograms, for example, in 58bdf8f.

Thus, the `finalizeSubprogram()` function is called for all definition
subprograms in `DIBuilder::finalize()` because they are stored in the
`AllSubprograms` by the `CreateFunction(isDefinition: true)` call. But
for the declaration subprograms, it should be called manually.

With this commit, `AllSubprograms` is used for holding and finalizing all DISubprograms.

Author: dzhidzhoev

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -4767,7 +4767,7 @@ void CGDebugInfo::EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc,
 
   // Preserve btf_decl_tag attributes for parameters of extern functions
   // for BPF target. The parameters created in this loop are attached as
-  // DISubprogram's retainedNodes in the subsequent finalizeSubprogram call.
+  // DISubprogram's retainedNodes in the DIBuilder::finalize() call.
   if (IsDeclForCallSite && CGM.getTarget().getTriple().isBPF()) {
     if (auto *FD = dyn_cast<FunctionDecl>(D)) {
       llvm::DITypeRefArray ParamTypes = STy->getTypeArray();
@@ -4784,8 +4784,6 @@ void CGDebugInfo::EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc,
 
   if (IsDeclForCallSite)
     Fn->setSubprogram(SP);
-
-  DBuilder.finalizeSubprogram(SP);
 }
 
 void CGDebugInfo::EmitFuncDeclForCallSite(llvm::CallBase *CallOrInvoke,

llvm/lib/IR/DIBuilder.cpp

@@ -943,8 +943,7 @@ DISubprogram *DIBuilder::createFunction(
       SPFlags, IsDefinition ? CUNode : nullptr, TParams, Decl, nullptr,
       ThrownTypes, Annotations, TargetFuncName);
 
-  if (IsDefinition)
-    AllSubprograms.push_back(Node);
+  AllSubprograms.push_back(Node);
   trackIfUnresolved(Node);
   return Node;
 }
@@ -981,8 +980,7 @@ DISubprogram *DIBuilder::createMethod(
       Flags, SPFlags, IsDefinition ? CUNode : nullptr, TParams, nullptr,
       nullptr, ThrownTypes);
 
-  if (IsDefinition)
-    AllSubprograms.push_back(SP);
+  AllSubprograms.push_back(SP);
   trackIfUnresolved(SP);
   return SP;
 }