Support loading files even when incorrect file name specified by the linker

"Incorrect" file name seen on Android whene the main executable is
called "app_process32" (or 64) but the linker specifies the package
name (e.g. com.android.calculator2). Additionally it can be present
in case of some linker bugs.

This CL adds logic to try to fetch the correct file name from the proc
file system based on the base address sepcified by the linker in case
we are failed to load the module by name.

Differential revision: http://reviews.llvm.org/D22219

llvm-svn: 276411

lldb/docs/lldb-gdb-remote.txt

@@ -888,6 +888,12 @@ tuples to return are:
     
     permissions:<permissions>;  // <permissions> is a string that contains one
                                 // or more of the characters from "rwx"
+
+    name:<name>; // <name> is a hex encoded string that contains the name of
+                 // the memory region mapped at the given address. In case of
+                 // regions backed by a file it have to be the absolute path of
+                 // the file while for anonymous regions it have to be the name
+                 // associated to the region if that is available.
                                 
     error:<ascii-byte-error-string>; // where <ascii-byte-error-string> is
                                      // a hex encoded string value that 

lldb/include/lldb/API/SBMemoryRegionInfo.h

@@ -86,6 +86,19 @@ public:
     bool
     IsMapped ();
 
+    
+    //------------------------------------------------------------------
+    /// Returns the name of the memory region mapped at the given
+    /// address.
+    ///
+    /// @return
+    ///     In case of memory mapped files it is the absolute path of
+    ///     the file otherwise it is a name associated with the memory
+    ///     region. If no name can be determined the returns nullptr.
+    //------------------------------------------------------------------
+    const char *
+    GetName();
+
     bool
     operator == (const lldb::SBMemoryRegionInfo &rhs) const;
 

lldb/include/lldb/Target/MemoryRegionInfo.h

@@ -10,6 +10,7 @@
 #ifndef lldb_MemoryRegionInfo_h
 #define lldb_MemoryRegionInfo_h
 
+#include "lldb/Core/ConstString.h"
 #include "lldb/Core/RangeMap.h"
 #include "lldb/Utility/Range.h"
 
@@ -81,6 +82,12 @@ namespace lldb_private
         {
             return m_mapped;
         }
+
+        const ConstString&
+        GetName () const
+        {
+            return m_name;
+        }
         
         void
         SetReadable (OptionalBool val)
@@ -106,6 +113,12 @@ namespace lldb_private
             m_mapped = val;
         }
 
+        void
+        SetName (const char* name)
+        {
+            m_name = ConstString(name);
+        }
+
         //----------------------------------------------------------------------
         // Get permissions as a uint32_t that is a mask of one or more bits from
         // the lldb::Permissions
@@ -157,6 +170,7 @@ namespace lldb_private
         OptionalBool m_write;
         OptionalBool m_execute;
         OptionalBool m_mapped;
+        ConstString m_name;
     };
 }
 

lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py

@@ -698,7 +698,7 @@ class GdbRemoteTestCaseBase(TestBase):
 
         # Validate keys are known.
         for (key, val) in list(mem_region_dict.items()):
-            self.assertTrue(key in ["start", "size", "permissions", "error"])
+            self.assertTrue(key in ["start", "size", "permissions", "name", "error"])
             self.assertIsNotNone(val)
 
         # Return the dictionary of key-value pairs for the memory region.

lldb/source/API/SBMemoryRegionInfo.cpp

@@ -110,6 +110,11 @@ SBMemoryRegionInfo::IsMapped () {
     return m_opaque_ap->GetMapped() == MemoryRegionInfo::eYes;
 }
 
+const char *
+SBMemoryRegionInfo::GetName () {
+    return m_opaque_ap->GetName().AsCString();
+}
+
 bool
 SBMemoryRegionInfo::GetDescription (SBStream &description)
 {

lldb/source/Core/DynamicLoader.cpp

@@ -12,13 +12,14 @@
 // Other libraries and framework includes
 // Project includes
 #include "lldb/lldb-private.h"
-#include "lldb/Target/DynamicLoader.h"
-#include "lldb/Target/Process.h"
-#include "lldb/Target/Target.h"
-#include "lldb/Core/PluginManager.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Core/ModuleSpec.h"
+#include "lldb/Core/PluginManager.h"
 #include "lldb/Core/Section.h"
+#include "lldb/Target/DynamicLoader.h"
+#include "lldb/Target/MemoryRegionInfo.h"
+#include "lldb/Target/Process.h"
+#include "lldb/Target/Target.h"
 
 using namespace lldb;
 using namespace lldb_private;
@@ -177,37 +178,67 @@ DynamicLoader::LoadModuleAtAddress(const FileSpec &file,
 {
     Target &target = m_process->GetTarget();
     ModuleList &modules = target.GetImages();
+    ModuleSpec module_spec (file, target.GetArchitecture());
     ModuleSP module_sp;
 
-    ModuleSpec module_spec (file, target.GetArchitecture());
     if ((module_sp = modules.FindFirstModule (module_spec)))
     {
         UpdateLoadedSections(module_sp, link_map_addr, base_addr, base_addr_is_offset);
+        return module_sp;
     }
-    else if ((module_sp = target.GetSharedModule(module_spec)))
+
+    if ((module_sp = target.GetSharedModule(module_spec)))
     {
         UpdateLoadedSections(module_sp, link_map_addr, base_addr, base_addr_is_offset);
+        return module_sp;
     }
-    else
-    {
-        if (base_addr_is_offset)
-        {
-            // Try to fetch the load address of the file from the process as we need absolute load
-            // address to read the file out of the memory instead of a load bias.
-            bool is_loaded = false;
-            lldb::addr_t load_addr;
-            Error error = m_process->GetFileLoadAddress(file, is_loaded, load_addr);
-            if (error.Success() && is_loaded)
-                base_addr = load_addr;
-        }
 
-        if ((module_sp = m_process->ReadModuleFromMemory(file, base_addr)))
+    bool check_alternative_file_name = true;
+    if (base_addr_is_offset)
+    {
+        // Try to fetch the load address of the file from the process as we need absolute load
+        // address to read the file out of the memory instead of a load bias.
+        bool is_loaded = false;
+        lldb::addr_t load_addr;
+        Error error = m_process->GetFileLoadAddress(file, is_loaded, load_addr);
+        if (error.Success() && is_loaded)
         {
-            UpdateLoadedSections(module_sp, link_map_addr, base_addr, false);
-            target.GetImages().AppendIfNeeded(module_sp);
+            check_alternative_file_name = false;
+            base_addr = load_addr;
         }
     }
 
+    // We failed to find the module based on its name. Lets try to check if we can find a
+    // different name based on the memory region info.
+    if (check_alternative_file_name)
+    {
+        MemoryRegionInfo memory_info;
+        Error error = m_process->GetMemoryRegionInfo(base_addr, memory_info);
+        if (error.Success() && memory_info.GetMapped() && memory_info.GetRange().GetRangeBase() == base_addr)
+        {
+            ModuleSpec new_module_spec(FileSpec(memory_info.GetName().AsCString(), false),
+                                       target.GetArchitecture());
+
+            if ((module_sp = modules.FindFirstModule(new_module_spec)))
+            {
+                UpdateLoadedSections(module_sp, link_map_addr, base_addr, false);
+                return module_sp;
+            }
+
+            if ((module_sp = target.GetSharedModule(new_module_spec)))
+            {
+                UpdateLoadedSections(module_sp, link_map_addr, base_addr, false);
+                return module_sp;
+            }
+        }
+    }
+
+    if ((module_sp = m_process->ReadModuleFromMemory(file, base_addr)))
+    {
+        UpdateLoadedSections(module_sp, link_map_addr, base_addr, false);
+        target.GetImages().AppendIfNeeded(module_sp);
+    }
+
     return module_sp;
 }
 

lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp

@@ -1678,6 +1678,20 @@ ParseMemoryRegionInfoFromProcMapsLine (const std::string &maps_line, MemoryRegio
     else
         return Error ("unexpected /proc/{pid}/maps exec permission char");
 
+    line_extractor.GetChar();              // Read the private bit
+    line_extractor.SkipSpaces();           // Skip the separator
+    line_extractor.GetHexMaxU64(false, 0); // Read the offset
+    line_extractor.GetHexMaxU64(false, 0); // Read the major device number
+    line_extractor.GetChar();              // Read the device id separator
+    line_extractor.GetHexMaxU64(false, 0); // Read the major device number
+    line_extractor.SkipSpaces();           // Skip the separator
+    line_extractor.GetU64(0, 10);          // Read the inode number
+
+    line_extractor.SkipSpaces();
+    const char* name = line_extractor.Peek();
+    if (name)
+        memory_region_info.SetName(name);
+
     return Error ();
 }
 

lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp

@@ -2458,6 +2458,13 @@ GDBRemoteCommunicationClient::GetMemoryRegionInfo (lldb::addr_t addr,
                         region_info.SetMapped(MemoryRegionInfo::eNo);
                     }
                 }
+                else if (name.compare ("name") == 0)
+                {
+                    StringExtractorGDBRemote name_extractor;
+                    name_extractor.GetStringRef().swap(value);
+                    name_extractor.GetHexByteString(value);
+                    region_info.SetName(value.c_str());
+                }
                 else if (name.compare ("error") == 0)
                 {
                     StringExtractorGDBRemote name_extractor;

lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp

@@ -2221,6 +2221,15 @@ GDBRemoteCommunicationServerLLGS::Handle_qMemoryRegionInfo (StringExtractorGDBRe
 
             response.PutChar (';');
         }
+
+        // Name
+        ConstString name = region_info.GetName();
+        if (name)
+        {
+            response.PutCString("name:");
+            response.PutCStringAsRawHex8(name.AsCString());
+            response.PutChar(';');
+        }
     }
 
     return SendPacketNoLock(response.GetData(), response.GetSize());