Don't try to parse ObjC method if CU isn't ObjC

[clayborg]

Summary

Improve manual indexing performance when indexing non objective C code. One question I have is all Darwin compilers currently support the apple DWARF indexes, so do we even need the objective C parsing code here?

[aprantl]

I suppose one could compile Objective-C code on Linux using GCC.

source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp

252

Since check_objc is only used here, I think it would be better for readability to say

if (cu_language == eLanguageTypeObjC ||
    cu_language == eLanguageTypeObjC_plus_plus)

here

[clayborg]

source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp

252

This is a hot loop. As long as the compiler will compute this once when optimizations are enabled, I am fine with inlining it into the if statement. But I pulled it out of the loop to ensure it only gets calculated once.

[clayborg]

In D63171#1539049, @aprantl wrote:

I suppose one could compile Objective-C code on Linux using GCC.

Will GCC not set the language to ObjC or ObjC++?

[aprantl]

In D63171#1539070, @clayborg wrote:

In D63171#1539049, @aprantl wrote:

I suppose one could compile Objective-C code on Linux using GCC.

Will GCC not set the language to ObjC or ObjC++?

This was intended as a reply to:

One question I have is all Darwin compilers currently support the apple DWARF indexes, so do we even need the objective C parsing code here?

source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp

252

cu_language is a constant, so it should be safe for the compiler to hoist the computation. Also, this computation is so cheap that I'd rather optimize for readability.

[labath]

In D63171#1539187, @aprantl wrote:

In D63171#1539070, @clayborg wrote:

In D63171#1539049, @aprantl wrote:

I suppose one could compile Objective-C code on Linux using GCC.

Will GCC not set the language to ObjC or ObjC++?

This was intended as a reply to:

One question I have is all Darwin compilers currently support the apple DWARF indexes, so do we even need the objective C parsing code here?

Also, i think I remember hearing that the apple indexes will not be emitted for jitted code, even on apple platforms, but this was just in passing, so I may not be totally correct here.

[clayborg]

Let compiler hoist "cu_language == eLanguageTypeObjC || cu_language == eLanguageTypeObjC_plus_plus" by inlining it into if statement so it is more readable.

[aprantl]

Thanks!

source/Plugins/SymbolFile/DWARF/ManualDWARFIndex.cpp

for (const DWARFDebugInfoEntry &die : unit.dies()) {
     }
 
     DIERef ref(unit.GetDebugSection(), cu_offset, die.GetOffset());
     switch (tag) {
     case DW_TAG_inlined_subroutine:
     case DW_TAG_subprogram:
       if (has_address) {
         if (name) {
+          bool is_objc_method = false;
+          if (cu_language == eLanguageTypeObjC ||
+              cu_language == eLanguageTypeObjC_plus_plus) {
             ObjCLanguage::MethodName objc_method(name, true);
             if (objc_method.IsValid(true)) {
-            ConstString objc_class_name_with_category(
+              is_objc_method = true;
+              ConstString class_name_with_category(
                   objc_method.GetClassNameWithCategory());
               ConstString objc_selector_name(objc_method.GetSelector());
               ConstString objc_fullname_no_category_name(
                   objc_method.GetFullNameWithoutCategory(true));
-            ConstString objc_class_name_no_category(objc_method.GetClassName());
+              ConstString class_name_no_category(objc_method.GetClassName());
               set.function_fullnames.Insert(ConstString(name), ref);
-            if (objc_class_name_with_category)
-              set.objc_class_selectors.Insert(objc_class_name_with_category,
-                                              ref);
-            if (objc_class_name_no_category &&
-                objc_class_name_no_category != objc_class_name_with_category)
-              set.objc_class_selectors.Insert(objc_class_name_no_category, ref);
+              if (class_name_with_category)
+                set.objc_class_selectors.Insert(class_name_with_category, ref);
+              if (class_name_no_category &&
+                  class_name_no_category != class_name_with_category)
+                set.objc_class_selectors.Insert(class_name_no_category, ref);
               if (objc_selector_name)
                 set.function_selectors.Insert(objc_selector_name, ref);
               if (objc_fullname_no_category_name)
                 set.function_fullnames.Insert(objc_fullname_no_category_name,
                                               ref);
             }
+          }
           // If we have a mangled name, then the DW_AT_name attribute is
           // usually the method name without the class or any parameters
           bool is_method = DWARFDIE(&unit, &die).IsMethod();
 
           if (is_method)
             set.function_methods.Insert(ConstString(name), ref);
           else
             set.function_basenames.Insert(ConstString(name), ref);
 
-          if (!is_method && !mangled_cstr && !objc_method.IsValid(true))
+          if (!is_method && !mangled_cstr && !is_objc_method)
             set.function_fullnames.Insert(ConstString(name), ref);
         }
         if (mangled_cstr) {
           // Make sure our mangled name isn't the same string table entry as
           // our name. If it starts with '_', then it is ok, else compare the
           // string to make sure it isn't the same and we don't end up with
           // duplicate entries
           if (name && name != mangled_cstr &&