Restrict the scope of a hack in DYLDRendezvous

[tberghammer]

Summary

Restrict the scope of a hack in DYLDRendezvous

The hack is there to work around an incorrect load address reported
by the android linker on API 21 and 22 devices. This CL restricts the
hack to those android API levels.

[labath]

looks good

source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp

421 ↗

(On Diff #36097)

This is condition is getting quite complicated. Consider putting it in a function (bool isBaseAddressBuggy(string file) perhaps?).

lldb/trunk/source/Plugins/DynamicLoader/POSIX-DYLD/DYLDRendezvous.cpp

 // Other libraries and framework includes
 #include "lldb/Core/ArchSpec.h"
 #include "lldb/Core/Error.h"
 #include "lldb/Core/Log.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Symbol/ObjectFile.h"
 #include "lldb/Symbol/Symbol.h"
 #include "lldb/Symbol/SymbolContext.h"
+#include "lldb/Target/Platform.h"
 #include "lldb/Target/Process.h"
 #include "lldb/Target/Target.h"
 
 #include "llvm/Support/Path.h"
 
 #include "DYLDRendezvous.h"
 
 using namespace lldb;
DYLDRendezvous::ReadStringFromMemory(addr_t addr)
     if (addr == LLDB_INVALID_ADDRESS)
         return std::string();
 
     m_process->ReadCStringFromMemory(addr, str, error);
 
     return str;
 }
 
+// Returns true if the load bias reported by the linker is incorrect for the given entry. This
+// function is used to handle cases where we want to work around a bug in the system linker.
+static bool
+isLoadBiasIncorrect(Target& target, const std::string& file_path)
+{
+    // On Android L (API 21, 22) the load address of the "/system/bin/linker" isn't filled in
+    // correctly.
+    uint32_t os_major = 0, os_minor = 0, os_update = 0;
+    if (target.GetArchitecture().GetTriple().getEnvironment() == llvm::Triple::Android &&
+        target.GetPlatform()->GetOSVersion(os_major, os_minor, os_update) &&
+        (os_major == 21 || os_major == 22) &&
+        (file_path == "/system/bin/linker" || file_path == "/system/bin/linker64"))
+    {
+        return true;
+    }
+
+    return false;
+}
+
 bool
 DYLDRendezvous::ReadSOEntryFromMemory(lldb::addr_t addr, SOEntry &entry)
 {
     entry.clear();
 
     entry.link_addr = addr;
     
     if (!(addr = ReadPointer(addr, &entry.base_addr)))
if (!(addr = ReadPointer(addr, &entry.next)))
         return false;
     
     if (!(addr = ReadPointer(addr, &entry.prev)))
         return false;
 
     std::string file_path = ReadStringFromMemory(entry.path_addr);
     entry.file_spec.SetFile(file_path, false);
 
-    // On Android L (5.0, 5.1) the load address of the "/system/bin/linker" isn't filled in
-    // correctly. To get the correct load address we fetch the load address of the file from the
-    // proc file system.
-    if (arch.GetTriple().getEnvironment() == llvm::Triple::Android && entry.base_addr == 0 &&
-        (file_path == "/system/bin/linker" || file_path == "/system/bin/linker64"))
+    // If the load bias reported by the linker is incorrect then fetch the load address of the file
+    // from the proc file system.
+    if (isLoadBiasIncorrect(m_process->GetTarget(), file_path))
     {
         lldb::addr_t load_addr = LLDB_INVALID_ADDRESS;
         bool is_loaded = false;
         Error error = m_process->GetFileLoadAddress(entry.file_spec, is_loaded, load_addr);
         if (error.Success() && is_loaded)
             entry.base_addr = load_addr;
     }
 

lldb/trunk/source/Plugins/Platform/Android/PlatformAndroid.h

public:
         Error
         PutFile (const FileSpec& source,
                  const FileSpec& destination,
                  uint32_t uid = UINT32_MAX,
                  uint32_t gid = UINT32_MAX) override;
         
         uint32_t
         GetSdkVersion();
-        
+        bool
+        GetRemoteOSVersion() override;
+
         Error
         DisconnectRemote () override;
 
      protected:
         const char *
         GetCacheHostname () override;
 
         Error

lldb/trunk/source/Plugins/Platform/Android/PlatformAndroid.cpp

command.Printf("oatdump --symbolize=%s --output=%s",
                    symfile_platform_filespec.GetCString(false));
     error = adb.Shell(command.GetData(), 60000 /* ms */, nullptr);
     if (error.Fail())
         return Error("Oatdump failed: %s", error.AsCString());
 
     // Download the symbolfile from the remote device
     return GetFile(symfile_platform_filespec, dst_file_spec);
 }
+
+bool
+PlatformAndroid::GetRemoteOSVersion ()
+{
+    m_major_os_version = GetSdkVersion();
+    m_minor_os_version = 0;
+    m_update_os_version = 0;
+    return m_major_os_version != 0;
+}