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

9 files changed, 118 insertions, 19 deletions

diff --git a/lldb/docs/lldb-gdb-remote.txt b/lldb/docs/lldb-gdb-remote.txt
index a882c4abda0..2fec87bdaf5 100644
--- a/lldb/docs/lldb-gdb-remote.txt
+++ b/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 
diff --git a/lldb/include/lldb/API/SBMemoryRegionInfo.h b/lldb/include/lldb/API/SBMemoryRegionInfo.h
index fadd0760891..16b767ff233 100644
--- a/lldb/include/lldb/API/SBMemoryRegionInfo.h
+++ b/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;
 
diff --git a/lldb/include/lldb/Target/MemoryRegionInfo.h b/lldb/include/lldb/Target/MemoryRegionInfo.h
index 5c82a1f294d..9c042905ef7 100644
--- a/lldb/include/lldb/Target/MemoryRegionInfo.h
+++ b/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;
     };
 }
 
diff --git a/lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py b/lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py
index d63ddbe3999..4db630d50d1 100644
--- a/lldb/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py
+++ b/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.
diff --git a/lldb/source/API/SBMemoryRegionInfo.cpp b/lldb/source/API/SBMemoryRegionInfo.cpp
index 53b180787af..1e4dd769644 100644
--- a/lldb/source/API/SBMemoryRegionInfo.cpp
+++ b/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)
 {
diff --git a/lldb/source/Core/DynamicLoader.cpp b/lldb/source/Core/DynamicLoader.cpp
index f41ff4a80c8..625cccc8e88 100644
--- a/lldb/source/Core/DynamicLoader.cpp
+++ b/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
+
+    bool check_alternative_file_name = true;
+    if (base_addr_is_offset)
     {
-        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)
         {
-            // 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;
+            check_alternative_file_name = false;
+            base_addr = load_addr;
         }
+    }
 
-        if ((module_sp = m_process->ReadModuleFromMemory(file, base_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)
         {
-            UpdateLoadedSections(module_sp, link_map_addr, base_addr, false);
-            target.GetImages().AppendIfNeeded(module_sp);
+            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;
 }
 
diff --git a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp b/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
index ae32a777773..6d822ce200f 100644
--- a/lldb/source/Plugins/Process/Linux/NativeProcessLinux.cpp
+++ b/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 ();
 }
 
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
index ac76889079a..ba018be812b 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp
+++ b/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;
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
index ede69769c79..4721e23f559 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationServerLLGS.cpp
+++ b/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());