Remove the hostname part from compilation directories extracted from DWARF

[mg11]

Summary

The DWARF2/3 standard definition from the DW_AT_comp_dir states a suggested form as "hostname:pathname". This patch removes the host part in order that calls such as stat and open can succeed.

source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

 #include "DWARFDIECollection.h"
 #include "DWARFFormValue.h"
 #include "DWARFLocationList.h"
 #include "LogChannelDWARF.h"
 #include "SymbolFileDWARFDebugMap.h"
 
 #include <map>
 
+#include <ctype.h>
+#include <string.h>
+
 //#define ENABLE_DEBUG_PRINTF // COMMENT OUT THIS LINE PRIOR TO CHECKIN
 
 #ifdef ENABLE_DEBUG_PRINTF
 #include <stdio.h>
 #define DEBUG_PRINTF(fmt, ...) printf(fmt, __VA_ARGS__)
 #else
 #define DEBUG_PRINTF(fmt, ...)
 #endif
switch (dwarf_accessibility)
         case DW_ACCESS_public:      return eAccessPublic;
         case DW_ACCESS_private:     return eAccessPrivate;
         case DW_ACCESS_protected:   return eAccessProtected;
         default:                    break;
     }
     return eAccessNone;
 }
 
+static const char*
+removeHostnameFromPathname(const char* path_from_dwarf)
+{
+    if (!path_from_dwarf || !path_from_dwarf[0])
+    {
+        return path_from_dwarf;
+    }
+
+    const char *colon_pos = strchr(path_from_dwarf, ':');
+    if (!colon_pos)
+    {
+        return path_from_dwarf;
+    }
+    
+    // check whether we have a windows path, and so the first character
+    // is a drive-letter not a hostname.
+    if (
+        colon_pos == path_from_dwarf + 1 &&
+        isalpha(*path_from_dwarf) &&
+        strlen(path_from_dwarf) > 2 &&
+        '\\' == path_from_dwarf[2])
+    {
+        return path_from_dwarf;
+    }
+
+    return colon_pos + 1;
+}
+
 #if defined(LLDB_CONFIGURATION_DEBUG) || defined(LLDB_CONFIGURATION_RELEASE)
 
 class DIEStack
 {
 public:
     
     void Push (DWARFCompileUnit *cu, const DWARFDebugInfoEntry *die)
     {
if (dwarf_cu)
                                 // the file.  This can be expensive e.g. when the source files are NFS mounted.
                                 if (module_sp->RemapSourceFile(cu_die_name, ramapped_file))
                                     cu_file_spec.SetFile (ramapped_file.c_str(), false);
                                 else
                                     cu_file_spec.SetFile (cu_die_name, false);
                             }
                             else
                             {
+                                // DWARF2/3 suggests the form hostname:pathname for compilation directory.
+                                // Remove the host part if present.
+                                cu_comp_dir = removeHostnameFromPathname(cu_comp_dir);
                                 std::string fullpath(cu_comp_dir);
+
                                 if (*fullpath.rbegin() != '/')
                                     fullpath += '/';
                                 fullpath += cu_die_name;
                                 if (module_sp->RemapSourceFile (fullpath.c_str(), ramapped_file))
                                     cu_file_spec.SetFile (ramapped_file.c_str(), false);
                                 else
                                     cu_file_spec.SetFile (fullpath.c_str(), false);
                             }
SymbolFileDWARF::ParseCompileUnitSupportFiles (const SymbolContext& sc, FileSpecList& support_files)
     DWARFCompileUnit* dwarf_cu = GetDWARFCompileUnit(sc.comp_unit);
     if (dwarf_cu)
     {
         const DWARFDebugInfoEntry * cu_die = dwarf_cu->GetCompileUnitDIEOnly();
 
         if (cu_die)
         {
             const char * cu_comp_dir = cu_die->GetAttributeValueAsString(this, dwarf_cu, DW_AT_comp_dir, NULL);
+
+            // DWARF2/3 suggests the form hostname:pathname for compilation directory.
+            // Remove the host part if present.
+            cu_comp_dir = removeHostnameFromPathname(cu_comp_dir);
+
             dw_offset_t stmt_list = cu_die->GetAttributeValueAsUnsigned(this, dwarf_cu, DW_AT_stmt_list, DW_INVALID_OFFSET);
 
             // All file indexes in DWARF are one based and a file of index zero is
             // supposed to be the compile unit itself.
             support_files.Append (*sc.comp_unit);
 
             return DWARFDebugLine::ParseSupportFiles(sc.comp_unit->GetModule(), get_debug_line_data(), cu_comp_dir, stmt_list, support_files);
         }