[ast] CreateParameterDeclaration should use an appropriate DeclContext.

Previously CreateParameterDeclaration was always using the translation
unit DeclContext.  We would later go and add parameters to the
FunctionDecl, but internally clang makes a copy when you do this, and
we'd end up with ParmVarDecl's at the global scope as well as in the
function scope.

This fixes the issue.  It's hard to say whether this will introduce
a behavioral change in name lookup, but I know there have been several
hacks introduced in previous years to deal with collisions between
various types of variables, so there's a chance that this patch could
obviate one of those hacks.

Differential Revision: https://reviews.llvm.org/D55571

llvm-svn: 348941

lldb/include/lldb/Symbol/ClangASTContext.h

@@ -401,7 +401,8 @@ public:
                                                type_quals, cc);
   }
 
-  clang::ParmVarDecl *CreateParameterDeclaration(const char *name,
+  clang::ParmVarDecl *CreateParameterDeclaration(clang::DeclContext *decl_ctx,
+                                                 const char *name,
                                                  const CompilerType &param_type,
                                                  int storage);
 

lldb/source/Plugins/SymbolFile/DWARF/DWARFASTParserClang.cpp

@@ -3407,8 +3407,9 @@ size_t DWARFASTParserClang::ParseChildParameters(
             function_param_types.push_back(type->GetForwardCompilerType());
 
             clang::ParmVarDecl *param_var_decl =
-                m_ast.CreateParameterDeclaration(
-                    name, type->GetForwardCompilerType(), storage);
+                m_ast.CreateParameterDeclaration(containing_decl_ctx, name,
+                                                 type->GetForwardCompilerType(),
+                                                 storage);
             assert(param_var_decl);
             function_param_decls.push_back(param_var_decl);
 

lldb/source/Plugins/SymbolFile/NativePDB/SymbolFileNativePDB.cpp

@@ -635,8 +635,8 @@ lldb::FunctionSP SymbolFileNativePDB::CreateFunction(PdbCompilandSymId func_id,
     PdbCompilandSymId param_uid(func_id.modi, record_offset);
     TypeSP type_sp = GetOrCreateType(param_type);
     clang::ParmVarDecl *param = m_clang->CreateParameterDeclaration(
-        param_name.str().c_str(), type_sp->GetForwardCompilerType(),
-        clang::SC_None);
+        function_decl, param_name.str().c_str(),
+        type_sp->GetForwardCompilerType(), clang::SC_None);
     lldbassert(m_uid_to_decl.count(toOpaqueUid(param_uid)) == 0);
 
     m_uid_to_decl[toOpaqueUid(param_uid)] = param;

lldb/source/Plugins/SymbolFile/PDB/PDBASTParser.cpp

@@ -932,7 +932,8 @@ PDBASTParser::GetDeclForSymbol(const llvm::pdb::PDBSymbol &symbol) {
             continue;
 
           clang::ParmVarDecl *param = m_ast.CreateParameterDeclaration(
-              nullptr, arg_type->GetForwardCompilerType(), clang::SC_None);
+              decl, nullptr, arg_type->GetForwardCompilerType(),
+              clang::SC_None);
           if (param)
             params.push_back(param);
         }

lldb/source/Symbol/ClangASTContext.cpp

@@ -2214,11 +2214,11 @@ CompilerType ClangASTContext::CreateFunctionType(
 }
 
 ParmVarDecl *ClangASTContext::CreateParameterDeclaration(
-    const char *name, const CompilerType &param_type, int storage) {
+    clang::DeclContext *decl_ctx, const char *name,
+    const CompilerType &param_type, int storage) {
   ASTContext *ast = getASTContext();
   assert(ast != nullptr);
-  return ParmVarDecl::Create(*ast, ast->getTranslationUnitDecl(),
-                             SourceLocation(), SourceLocation(),
+  return ParmVarDecl::Create(*ast, decl_ctx, SourceLocation(), SourceLocation(),
                              name && name[0] ? &ast->Idents.get(name) : nullptr,
                              ClangUtil::GetQualType(param_type), nullptr,
                              (clang::StorageClass)storage, nullptr);