Adds lldb support for querying the register mapping from gdbserver re…

…mote targets using qXfer:features:read packet. Only enabled if libxml2 enabled in build.

Differential Revision: http://reviews.llvm.org/D8999

llvm-svn: 235109

lldb/cmake/modules/LLDBConfig.cmake

@@ -187,29 +187,39 @@ install(DIRECTORY include/
   DESTINATION include
   FILES_MATCHING
   PATTERN "*.h"
-  PATTERN ".svn" EXCLUDE
-  )
-
-
-# Find libraries or frameworks that may be needed
-if (CMAKE_SYSTEM_NAME MATCHES "Darwin")
+  PATTERN ".svn" EXCLUDE
+  )
+
+if (NOT LIBXML2_FOUND)
+  find_package(LibXml2)
+endif()
+
+# Find libraries or frameworks that may be needed
+if (CMAKE_SYSTEM_NAME MATCHES "Darwin")
   find_library(CARBON_LIBRARY Carbon)
   find_library(FOUNDATION_LIBRARY Foundation)
   find_library(CORE_FOUNDATION_LIBRARY CoreFoundation)
   find_library(CORE_SERVICES_LIBRARY CoreServices)
-  find_library(SECURITY_LIBRARY Security)
-  find_library(DEBUG_SYMBOLS_LIBRARY DebugSymbols PATHS "/System/Library/PrivateFrameworks")
-
-  if (NOT LIBXML2_FOUND)
-    find_package(LibXml2)
-  endif ()
-  list(APPEND system_libs xml2 ncurses panel)
-  list(APPEND system_libs ${CARBON_LIBRARY} ${FOUNDATION_LIBRARY}
-  ${CORE_FOUNDATION_LIBRARY} ${CORE_SERVICES_LIBRARY} ${SECURITY_LIBRARY}
-  ${DEBUG_SYMBOLS_LIBRARY})
-endif()
-
-if(LLDB_REQUIRES_EH)
+  find_library(SECURITY_LIBRARY Security)
+  find_library(DEBUG_SYMBOLS_LIBRARY DebugSymbols PATHS "/System/Library/PrivateFrameworks")
+
+  add_definitions( -DLIBXML2_DEFINED )
+  list(APPEND system_libs xml2 ncurses panel)
+  list(APPEND system_libs ${CARBON_LIBRARY} ${FOUNDATION_LIBRARY}
+  ${CORE_FOUNDATION_LIBRARY} ${CORE_SERVICES_LIBRARY} ${SECURITY_LIBRARY}
+  ${DEBUG_SYMBOLS_LIBRARY})
+
+else()
+
+  if (LIBXML2_FOUND)
+    add_definitions( -DLIBXML2_DEFINED )
+    list(APPEND system_libs ${LIBXML2_LIBRARIES})
+    include_directories(${LIBXML2_INCLUDE_DIR})
+  endif()
+
+endif()
+
+if(LLDB_REQUIRES_EH)
   set(LLDB_REQUIRES_RTTI ON)
 else()
   if(LLVM_COMPILER_IS_GCC_COMPATIBLE)

lldb/source/Commands/CommandObjectRegister.cpp

@@ -144,7 +144,7 @@ class CommandObjectRegisterRead : public CommandObjectParsed
         const RegisterSet * const reg_set = reg_ctx->GetRegisterSet(set_idx);
         if (reg_set)
         {
-            strm.Printf ("%s:\n", reg_set->name);
+            strm.Printf ("%s:\n", (reg_set->name ? reg_set->name : "unknown") );
             strm.IndentMore ();
             const size_t num_registers = reg_set->num_registers;
             for (size_t reg_idx = 0; reg_idx < num_registers; ++reg_idx)

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

@@ -79,6 +79,7 @@ GDBRemoteCommunicationClient::GDBRemoteCommunicationClient() :
     m_supports_QSaveRegisterState (eLazyBoolCalculate),
     m_supports_qXfer_auxv_read (eLazyBoolCalculate),
     m_supports_qXfer_libraries_read (eLazyBoolCalculate),
+    m_supports_qXfer_features_read (eLazyBoolCalculate),
     m_supports_qXfer_libraries_svr4_read (eLazyBoolCalculate),
     m_supports_augmented_libraries_svr4_read (eLazyBoolCalculate),
     m_supports_jThreadExtendedInfo (eLazyBoolCalculate),
@@ -214,6 +215,16 @@ GDBRemoteCommunicationClient::GetQXferAuxvReadSupported ()
     return (m_supports_qXfer_auxv_read == eLazyBoolYes);
 }
 
+bool
+GDBRemoteCommunicationClient::GetQXferFeaturesReadSupported ()
+{
+    if (m_supports_qXfer_features_read == eLazyBoolCalculate)
+    {
+        GetRemoteQSupported();
+    }
+    return (m_supports_qXfer_features_read == eLazyBoolYes);
+}
+
 uint64_t
 GDBRemoteCommunicationClient::GetRemoteMaxPacketSize()
 {
@@ -335,6 +346,7 @@ GDBRemoteCommunicationClient::ResetDiscoverableSettings()
     m_supports_qXfer_auxv_read = eLazyBoolCalculate;
     m_supports_qXfer_libraries_read = eLazyBoolCalculate;
     m_supports_qXfer_libraries_svr4_read = eLazyBoolCalculate;
+    m_supports_qXfer_features_read = eLazyBoolCalculate;
     m_supports_augmented_libraries_svr4_read = eLazyBoolCalculate;
 
     m_supports_qProcessInfoPID = true;
@@ -373,10 +385,21 @@ GDBRemoteCommunicationClient::GetRemoteQSupported ()
     m_supports_qXfer_libraries_read = eLazyBoolNo;
     m_supports_qXfer_libraries_svr4_read = eLazyBoolNo;
     m_supports_augmented_libraries_svr4_read = eLazyBoolNo;
+    m_supports_qXfer_features_read = eLazyBoolNo;
     m_max_packet_size = UINT64_MAX;  // It's supposed to always be there, but if not, we assume no limit
 
+    // build the qSupported packet
+    std::vector<std::string> features = {"xmlRegisters=i386,arm,mips"};
+    StreamString packet;
+    packet.PutCString( "qSupported" );
+    for ( uint32_t i = 0; i < features.size( ); ++i )
+    {
+        packet.PutCString( i==0 ? ":" : ";");
+        packet.PutCString( features[i].c_str( ) );
+    }
+
     StringExtractorGDBRemote response;
-    if (SendPacketAndWaitForResponse("qSupported",
+    if (SendPacketAndWaitForResponse(packet.GetData(),
                                      response,
                                      /*send_async=*/false) == PacketResult::Success)
     {
@@ -392,6 +415,8 @@ GDBRemoteCommunicationClient::GetRemoteQSupported ()
         }
         if (::strstr (response_cstr, "qXfer:libraries:read+"))
             m_supports_qXfer_libraries_read = eLazyBoolYes;
+        if (::strstr (response_cstr, "qXfer:features:read+"))
+            m_supports_qXfer_features_read = eLazyBoolYes;
 
         const char *packet_size_str = ::strstr (response_cstr, "PacketSize=");
         if (packet_size_str)
@@ -3776,3 +3801,74 @@ GDBRemoteCommunicationClient::GetModuleInfo (const FileSpec& module_file_spec,
 
     return true;
 }
+
+// query the target remote for extended information using the qXfer packet
+//
+// example: object='features', annex='target.xml', out=<xml output>
+// return:  'true'  on success
+//          'false' on failure (err set)
+bool
+GDBRemoteCommunicationClient::ReadExtFeature (const lldb_private::ConstString object,
+                                              const lldb_private::ConstString annex,
+                                              std::string & out,
+                                              lldb_private::Error & err) {
+
+    std::stringstream output;
+    StringExtractorGDBRemote chunk;
+
+    const int size   = 0xfff;
+    int       offset = 0;
+    bool      active = true;
+
+    // loop until all data has been read
+    while ( active ) {
+
+        // send query extended feature packet
+        std::stringstream packet;
+        packet << "qXfer:" 
+               << object.AsCString( ) << ":read:" 
+               << annex.AsCString( )  << ":" 
+               << std::hex << offset  << "," 
+               << std::hex << size;
+
+        GDBRemoteCommunication::PacketResult res =
+            SendPacketAndWaitForResponse( packet.str().c_str(),
+                                          chunk,
+                                          false );
+
+        if ( res != GDBRemoteCommunication::PacketResult::Success ) {
+            err.SetErrorString( "Error sending $qXfer packet" );
+            return false;
+        }
+
+        const std::string & str = chunk.GetStringRef( );
+        if ( str.length() == 0 ) {
+            // should have some data in chunk
+            err.SetErrorString( "Empty response from $qXfer packet" );
+            return false;
+        }
+
+        // check packet code
+        switch ( str[0] ) {
+            // last chunk
+        case ( 'l' ):
+            active = false;
+            // fall through intensional
+
+            // more chunks
+        case ( 'm' ) :
+            if ( str.length() > 1 )
+                output << &str[1];
+            break;
+
+            // unknown chunk
+        default:
+            err.SetErrorString( "Invalid continuation code from $qXfer packet" );
+            return false;
+        }
+    }
+
+    out = output.str( );
+    err.Success( );
+    return true;
+}

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

@@ -426,6 +426,9 @@ class GDBRemoteCommunicationClient : public GDBRemoteCommunication
     bool
     GetAugmentedLibrariesSVR4ReadSupported ();
 
+    bool
+    GetQXferFeaturesReadSupported ();
+
     LazyBool
     SupportsAllocDeallocMemory () // const
     {
@@ -533,6 +536,12 @@ class GDBRemoteCommunicationClient : public GDBRemoteCommunication
                    const ArchSpec& arch_spec,
                    ModuleSpec &module_spec);
 
+    bool
+    ReadExtFeature (const lldb_private::ConstString object,
+                    const lldb_private::ConstString annex,
+                    std::string & out,
+                    lldb_private::Error & err);
+
 protected:
 
     PacketResult
@@ -576,6 +585,7 @@ class GDBRemoteCommunicationClient : public GDBRemoteCommunication
     LazyBool m_supports_qXfer_auxv_read;
     LazyBool m_supports_qXfer_libraries_read;
     LazyBool m_supports_qXfer_libraries_svr4_read;
+    LazyBool m_supports_qXfer_features_read;
     LazyBool m_supports_augmented_libraries_svr4_read;
     LazyBool m_supports_jThreadExtendedInfo;