Only the top-level section should be considered for renaming

The Linux kernel first places `jiffies64` in .data, and later refines
that to .data..cacheline_aligned. The latter still is within the .data
section, though, so just use the .data part for renaming.

Author: tautschnig

src/ansi-c/c_typecheck_base.cpp

@@ -721,8 +721,18 @@ void c_typecheck_baset::typecheck_declaration(
         apply_asm_label(full_spec.asm_label, symbol);
       else
       {
-        std::string asm_name;
-        asm_name=id2string(full_spec.section)+"$$";
+        // section name is not empty, do a bit of parsing
+        std::string asm_name = id2string(full_spec.section);
+        if(asm_name[0] != '.')
+        {
+          warning().source_location = symbol.location;
+          warning() << "section name `" << asm_name
+                    << "' expected to start with `.'" << eom;
+        }
+        std::string::size_type primary_section = asm_name.find('.', 1);
+        if(primary_section != std::string::npos)
+          asm_name.resize(primary_section);
+        asm_name += "$$";
         if(!full_spec.asm_label.empty())
           asm_name+=id2string(full_spec.asm_label);
         else