Improve the arm/aarch64 mapping symbol handling

Change the mapping symbol handling to handle the case when the mapping
symbols are prefixed with an arbitrary prefix. This isn't strictly standard
compliance, but if all symbols in an object file is prefixed with objcopy
then the prefix will be added to the mapping symbol also. We still want to
treat these symbols as mapping symbols to get the correct address class data.

Differential revision: http://reviews.llvm.org/D12755

llvm-svn: 247400

diff --git a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
index c9b1e0d..b500acf 100644 (file)
--- a/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
+++ b/lldb/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
@@ -1854,6 +1854,25 @@ ObjectFileELF::CreateSections(SectionList &unified_section_list)
     }
 }
 
+// Find the arm/aarch64 mapping symbol character in the given symbol name. Maping symbols have the
+// form of "$<char>[.<any>]*". Additionally we recognize cases when the mapping symbol prefixed by
+// an arbitrary string because if a symbol prefix added to each symbol in the object file with
+// objcopy then the mapping symbols are also prefixed.
+static char
+FindArmAarch64MappingSymbol(const char* symbol_name)
+{
+    if (!symbol_name)
+        return '\0';
+
+    const char* dollar_pos = ::strchr(symbol_name, '$');
+    if (!dollar_pos || dollar_pos[1] == '\0')
+        return '\0';
+
+    if (dollar_pos[2] == '\0' || dollar_pos[2] == '.')
+        return dollar_pos[1];
+    return '\0';
+}
+
 // private
 unsigned
 ObjectFileELF::ParseSymbols (Symtab *symtab,
@@ -1999,58 +2018,54 @@ ObjectFileELF::ParseSymbols (Symtab *symtab,
         {
             if (arch.GetMachine() == llvm::Triple::arm)
             {
-                if (symbol.getBinding() == STB_LOCAL && symbol_name && symbol_name[0] == '$')
+                if (symbol.getBinding() == STB_LOCAL)
                 {
-                    // These are reserved for the specification (e.g.: mapping
-                    // symbols). We don't want to add them to the symbol table.
-
+                    char mapping_symbol = FindArmAarch64MappingSymbol(symbol_name);
                     if (symbol_type == eSymbolTypeCode)
                     {
-                        llvm::StringRef symbol_name_ref(symbol_name);
-                        if (symbol_name_ref == "$a" || symbol_name_ref.startswith("$a."))
+                        switch (mapping_symbol)
                         {
-                            // $a[.<any>]* - marks an ARM instruction sequence
-                            m_address_class_map[symbol.st_value] = eAddressClassCode;
-                        }
-                        else if (symbol_name_ref == "$b" || symbol_name_ref.startswith("$b.") ||
-                                 symbol_name_ref == "$t" || symbol_name_ref.startswith("$t."))
-                        {
-                            // $b[.<any>]* - marks a THUMB BL instruction sequence
-                            // $t[.<any>]* - marks a THUMB instruction sequence
-                            m_address_class_map[symbol.st_value] = eAddressClassCodeAlternateISA;
-                        }
-                        else if (symbol_name_ref == "$d" || symbol_name_ref.startswith("$d."))
-                        {
-                            // $d[.<any>]* - marks a data item sequence (e.g. lit pool)
-                            m_address_class_map[symbol.st_value] = eAddressClassData;
+                            case 'a':
+                                // $a[.<any>]* - marks an ARM instruction sequence
+                                m_address_class_map[symbol.st_value] = eAddressClassCode;
+                                break;
+                            case 'b':
+                            case 't':
+                                // $b[.<any>]* - marks a THUMB BL instruction sequence
+                                // $t[.<any>]* - marks a THUMB instruction sequence
+                                m_address_class_map[symbol.st_value] = eAddressClassCodeAlternateISA;
+                                break;
+                            case 'd':
+                                // $d[.<any>]* - marks a data item sequence (e.g. lit pool)
+                                m_address_class_map[symbol.st_value] = eAddressClassData;
+                                break;
                         }
                     }
-                    continue;
+                    if (mapping_symbol)
+                        continue;
                 }
             }
             else if (arch.GetMachine() == llvm::Triple::aarch64)
             {
-                if (symbol.getBinding() == STB_LOCAL && symbol_name && symbol_name[0] == '$')
+                if (symbol.getBinding() == STB_LOCAL)
                 {
-                    // These are reserved for the specification (e.g.: mapping
-                    // symbols). We don't want to add them to the symbol table.
-
+                    char mapping_symbol = FindArmAarch64MappingSymbol(symbol_name);
                     if (symbol_type == eSymbolTypeCode)
                     {
-                        llvm::StringRef symbol_name_ref(symbol_name);
-                        if (symbol_name_ref == "$x" || symbol_name_ref.startswith("$x."))
-                        {
-                            // $x[.<any>]* - marks an A64 instruction sequence
-                            m_address_class_map[symbol.st_value] = eAddressClassCode;
-                        }
-                        else if (symbol_name_ref == "$d" || symbol_name_ref.startswith("$d."))
+                        switch (mapping_symbol)
                         {
-                            // $d[.<any>]* - marks a data item sequence (e.g. lit pool)
-                            m_address_class_map[symbol.st_value] = eAddressClassData;
+                            case 'x':
+                                // $x[.<any>]* - marks an A64 instruction sequence
+                                m_address_class_map[symbol.st_value] = eAddressClassCode;
+                                break;
+                            case 'd':
+                                // $d[.<any>]* - marks a data item sequence (e.g. lit pool)
+                                m_address_class_map[symbol.st_value] = eAddressClassData;
+                                break;
                         }
                     }
-
-                    continue;
+                    if (mapping_symbol)
+                        continue;
                 }
             }