Only check for _ZN function prefix in Linux and FreeBSD targets in SymbolFileDWARF

[flackr]

Summary

In http://reviews.llvm.org/D9754 I enabled the mangled symbol name lookup workaround used to find global and anonymous namespace symbols in linux binaries for all platforms, however we should still only check for these symbols when processing Linux or FreeBSD binaries where they are relevant. This patch makes this change.

[ted]

This codepath also fixes mangling issues with Hexagon binaries. Please add

|| (arch.GetTriple().GetMachine() == llvm::Triple::hexagon)

to the if, to pick up the fix for Hexagon.

You also might want to move

SymbolContextList temp_sc_list;
FindFunctions (name, m_function_basename_index, include_inlines, temp_sc_list);

inside the if so extra code isn't run unecessarily.

I don't think it's a (Linux or FreeBSD) issue; I think it's a ((clang or gcc) and not Darwin) issue.

[flackr]

• Check for hexagon machine.
• Added comment to fix object arch on Windows and detect global / anonymous namespace symbols there.

[flackr]

zturner, I added a comment about Windows like you suggested.

In D9782#173178, @ted wrote:

This codepath also fixes mangling issues with Hexagon binaries. Please add

|| (arch.GetTriple().GetMachine() == llvm::Triple::hexagon)

to the if, to pick up the fix for Hexagon.

Done.

You also might want to move

SymbolContextList temp_sc_list;
FindFunctions (name, m_function_basename_index, include_inlines, temp_sc_list);

inside the if so extra code isn't run unecessarily.

Done.

I don't think it's a (Linux or FreeBSD) issue; I think it's a ((clang or gcc) and not Darwin) issue.

[zturner]

looks good

lldb/trunk/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

 #include "clang/Basic/LangOptions.h"
 #include "clang/Basic/SourceManager.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/Specifiers.h"
 #include "clang/Sema/DeclSpec.h"
 
 #include "llvm/Support/Casting.h"
 
+#include "lldb/Core/ArchSpec.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Core/ModuleList.h"
 #include "lldb/Core/ModuleSpec.h"
 #include "lldb/Core/PluginManager.h"
 #include "lldb/Core/RegularExpression.h"
 #include "lldb/Core/Scalar.h"
 #include "lldb/Core/Section.h"
 #include "lldb/Core/StreamFile.h"
else
         if (name_type_mask & eFunctionNameTypeFull)
         {
             FindFunctions (name, m_function_fullname_index, include_inlines, sc_list);
 
             // FIXME Temporary workaround for global/anonymous namespace
             // functions debugging FreeBSD and Linux binaries.
             // If we didn't find any functions in the global namespace try
             // looking in the basename index but ignore any returned
-            // functions that have a namespace (ie. mangled names starting with 
-            // '_ZN') but keep functions which have an anonymous namespace
+            // functions that have a namespace but keep functions which
+            // have an anonymous namespace
+            // TODO: The arch in the object file isn't correct for MSVC
+            // binaries on windows, we should find a way to make it
+            // correct and handle those symbols as well.
             if (sc_list.GetSize() == 0)
             {
+                ArchSpec arch;
+                if (!namespace_decl &&
+                    GetObjectFile()->GetArchitecture(arch) &&
+                    (arch.GetTriple().isOSFreeBSD() || arch.GetTriple().isOSLinux() ||
+                     arch.GetMachine() == llvm::Triple::hexagon))
+                {
                     SymbolContextList temp_sc_list;
                     FindFunctions (name, m_function_basename_index, include_inlines, temp_sc_list);
-                if (!namespace_decl)
-                {
                     SymbolContext sc;
                     for (uint32_t i = 0; i < temp_sc_list.GetSize(); i++)
                     {
                         if (temp_sc_list.GetContextAtIndex(i, sc))
                         {
                             ConstString mangled_name = sc.GetFunctionName(Mangled::ePreferMangled);
                             ConstString demangled_name = sc.GetFunctionName(Mangled::ePreferDemangled);
+                            // Mangled names on Linux and FreeBSD are of the form:
+                            // _ZN18function_namespace13function_nameEv.
                             if (strncmp(mangled_name.GetCString(), "_ZN", 3) ||
                                 !strncmp(demangled_name.GetCString(), "(anonymous namespace)", 21))
                             {
                                 sc_list.Append(sc);
                             }
                         }
                     }
                 }