ComputeSupportExeDirectory for Linux

[chaoren]

Summary

Fixes http://reviews.llvm.org/D8511

The original method of using dladdr() could return the incorrect relative
path if not dynamically linked against liblldb and the working directory
has changed. This is not a problem when built with python, since
ScriptInterpreterPython::InitializePrivate calls
HostInfo::GetLLDBPath(ePathTypeLLDBShlibDir, ...) and caches the
correct path before any changes to the working directory.

The /proc/self/exe approach fails if run using Python, but works for all other
cases (including for android, which doesn't have dladdr()).

So if we combine the two, we should reasonably cover all corner cases.

[ovyalov]

source/Host/linux/HostInfoLinux.cpp

225

Do we need to keep this method around since HostInfoPosix::ComputeSupportExeDirectory uses GetLLDBPath(lldb::ePathTypeLLDBShlibDir..) ?

[chaoren]

source/Host/linux/HostInfoLinux.cpp

225

This was added by me to fix this same problem. HostInfoPosix::ComputeSupportExeDirectory really wants to call HostInfoBase::ComputeSharedLibraryDirectory. I think it's more correct to move it to SupportExe because if dladdr() fails, then there should be no shared library anyway.

[ovyalov]

lgtm

[clayborg]

lgtm

include/lldb/Host/android/HostInfoAndroid.h

class HostInfoAndroid : public HostInfoLinux
     friend class HostInfoBase;
 
   public:
     static FileSpec GetDefaultShell();
     static FileSpec ResolveLibraryPath (const std::string& path, const ArchSpec& arch);
 
   protected:
     static void ComputeHostArchitectureSupport(ArchSpec &arch_32, ArchSpec &arch_64);
-    static bool ComputeSupportExeDirectory(FileSpec &file_spec);
 };
 
 } // end of namespace lldb_private
 
 #endif // #ifndef lldb_Host_android_HostInfoAndroid_h_

include/lldb/Host/linux/HostInfoLinux.h

public:
 
     static bool GetOSVersion(uint32_t &major, uint32_t &minor, uint32_t &update);
     static bool GetOSBuildString(std::string &s);
     static bool GetOSKernelDescription(std::string &s);
     static llvm::StringRef GetDistributionId();
     static FileSpec GetProgramFileSpec();
 
   protected:
-    static bool ComputeSharedLibraryDirectory(FileSpec &file_spec);
+    static bool ComputeSupportExeDirectory(FileSpec &file_spec);
     static bool ComputeSystemPluginsDirectory(FileSpec &file_spec);
     static bool ComputeUserPluginsDirectory(FileSpec &file_spec);
     static void ComputeHostArchitectureSupport(ArchSpec &arch_32, ArchSpec &arch_64);
 };
 }
 
 #endif

source/Host/android/HostInfoAndroid.cpp

if (arch_32.IsValid())
         arch_32.GetTriple().setEnvironment(llvm::Triple::Android);
     }
     if (arch_64.IsValid())
     {
         arch_64.GetTriple().setEnvironment(llvm::Triple::Android);
     }
 }
 
-bool
-HostInfoAndroid::ComputeSupportExeDirectory(FileSpec &file_spec)
-{
-    file_spec.GetDirectory() = HostInfoLinux::GetProgramFileSpec().GetDirectory();
-    return (bool)file_spec.GetDirectory();
-}
-
 FileSpec
 HostInfoAndroid::GetDefaultShell()
 {
     return FileSpec("/system/bin/sh", false);
 }
 
 FileSpec
 HostInfoAndroid::ResolveLibraryPath(const std::string& module_path, const ArchSpec& arch)

source/Host/common/Host.cpp

Host::GetModuleFileSpecForHostAddress (const void *host_addr)
     FileSpec module_filespec;
 #if !defined(__ANDROID__) && !defined(__ANDROID_NDK__)
     Dl_info info;
     if (::dladdr (host_addr, &info))
     {
         if (info.dli_fname)
             module_filespec.SetFile(info.dli_fname, true);
     }
-#else
-    assert(false && "dladdr() not supported on Android");
 #endif
     return module_filespec;
 }
 
 #endif
 
 #if !defined(__linux__)
 bool

source/Host/linux/HostInfoLinux.cpp

if (!g_program_filespec)
             g_program_filespec.SetFile(exe_path, false);
         }
     }
 
     return g_program_filespec;
 }
 
 bool
-HostInfoLinux::ComputeSharedLibraryDirectory(FileSpec &file_spec)
+HostInfoLinux::ComputeSupportExeDirectory(FileSpec &file_spec)
 {
-    if (HostInfoPosix::ComputeSharedLibraryDirectory(file_spec))
+    if (HostInfoPosix::ComputeSupportExeDirectory(file_spec) && file_spec.Exists())
         return true;
     file_spec.GetDirectory() = GetProgramFileSpec().GetDirectory();
-    return (bool)file_spec.GetDirectory();
+    return !file_spec.GetDirectory().IsEmpty();
 }
 
 bool
 HostInfoLinux::ComputeSystemPluginsDirectory(FileSpec &file_spec)
 {
     FileSpec temp_file("/usr/lib/lldb", true);
     file_spec.GetDirectory().SetCString(temp_file.GetPath().c_str());
     return true;