diff options
| -rw-r--r-- | lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp | 34 | ||||
| -rw-r--r-- | lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp | 122 |
2 files changed, 97 insertions, 59 deletions
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp index ff12b65ba64..ab3bf7f5aa2 100644 --- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp +++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunicationClient.cpp @@ -2675,15 +2675,10 @@ GDBRemoteCommunicationClient::GetThreadStopInfo (lldb::tid_t tid, StringExtracto uint8_t GDBRemoteCommunicationClient::SendGDBStoppointTypePacket (GDBStoppointType type, bool insert, addr_t addr, uint32_t length) { - switch (type) - { - case eBreakpointSoftware: if (!m_supports_z0) return UINT8_MAX; break; - case eBreakpointHardware: if (!m_supports_z1) return UINT8_MAX; break; - case eWatchpointWrite: if (!m_supports_z2) return UINT8_MAX; break; - case eWatchpointRead: if (!m_supports_z3) return UINT8_MAX; break; - case eWatchpointReadWrite: if (!m_supports_z4) return UINT8_MAX; break; - } - + // Check if the stub is known not to support this breakpoint type + if (!SupportsGDBStoppointPacket(type)) + return UINT8_MAX; + // Construct the breakpoint packet char packet[64]; const int packet_len = ::snprintf (packet, sizeof(packet), @@ -2692,28 +2687,35 @@ GDBRemoteCommunicationClient::SendGDBStoppointTypePacket (GDBStoppointType type, type, addr, length); - + // Check we havent overwritten the end of the packet buffer assert (packet_len + 1 < (int)sizeof(packet)); StringExtractorGDBRemote response; + // Try to send the breakpoint packet, and check that it was correctly sent if (SendPacketAndWaitForResponse(packet, packet_len, response, true) == PacketResult::Success) { + // Receive and OK packet when the breakpoint successfully placed if (response.IsOKResponse()) return 0; - else if (response.IsErrorResponse()) + + // Error while setting breakpoint, send back specific error + if (response.IsErrorResponse()) return response.GetError(); - } - else - { - switch (type) + + // Empty packet informs us that breakpoint is not supported + if (response.IsUnsupportedResponse()) { + // Disable this breakpoint type since it is unsupported + switch (type) + { case eBreakpointSoftware: m_supports_z0 = false; break; case eBreakpointHardware: m_supports_z1 = false; break; case eWatchpointWrite: m_supports_z2 = false; break; case eWatchpointRead: m_supports_z3 = false; break; case eWatchpointReadWrite: m_supports_z4 = false; break; + } } } - + // Signal generic faliure return UINT8_MAX; } diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp index 96701bd830a..1a73f6a30df 100644 --- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp +++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp @@ -2310,70 +2310,106 @@ Error ProcessGDBRemote::EnableBreakpointSite (BreakpointSite *bp_site) { Error error; - assert (bp_site != NULL); + assert(bp_site != NULL); - Log *log (ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_BREAKPOINTS)); + // Get logging info + Log *log(ProcessGDBRemoteLog::GetLogIfAllCategoriesSet(GDBR_LOG_BREAKPOINTS)); user_id_t site_id = bp_site->GetID(); + + // Get the breakpoint address const addr_t addr = bp_site->GetLoadAddress(); + + // Log that a breakpoint was requested if (log) - log->Printf ("ProcessGDBRemote::EnableBreakpointSite (size_id = %" PRIu64 ") address = 0x%" PRIx64, site_id, (uint64_t)addr); + log->Printf("ProcessGDBRemote::EnableBreakpointSite (size_id = %" PRIu64 ") address = 0x%" PRIx64, site_id, (uint64_t)addr); + // Breakpoint already exists and is enabled if (bp_site->IsEnabled()) { if (log) - log->Printf ("ProcessGDBRemote::EnableBreakpointSite (size_id = %" PRIu64 ") address = 0x%" PRIx64 " -- SUCCESS (already enabled)", site_id, (uint64_t)addr); + log->Printf("ProcessGDBRemote::EnableBreakpointSite (size_id = %" PRIu64 ") address = 0x%" PRIx64 " -- SUCCESS (already enabled)", site_id, (uint64_t)addr); return error; } - else + + // Get the software breakpoint trap opcode size + const size_t bp_op_size = GetSoftwareBreakpointTrapOpcode(bp_site); + + // SupportsGDBStoppointPacket() simply checks a boolean, indicating if this breakpoint type + // is supported by the remote stub. These are set to true by default, and later set to false + // only after we receive an unimplemented response when sending a breakpoint packet. This means + // initially that unless we were specifically instructed to use a hardware breakpoint, LLDB will + // attempt to set a software breakpoint. HardwareRequired() also queries a boolean variable which + // indicates if the user specifically asked for hardware breakpoints. If true then we will + // skip over software breakpoints. + if (m_gdb_comm.SupportsGDBStoppointPacket(eBreakpointSoftware) && (!bp_site->HardwareRequired())) { - const size_t bp_op_size = GetSoftwareBreakpointTrapOpcode (bp_site); + // Try to send off a software breakpoint packet ($Z0) + if (m_gdb_comm.SendGDBStoppointTypePacket(eBreakpointSoftware, true, addr, bp_op_size) == 0) + { + // The breakpoint was placed successfully + bp_site->SetEnabled(true); + bp_site->SetType(BreakpointSite::eExternal); + return error; + } - if (bp_site->HardwareRequired()) + // SendGDBStoppointTypePacket() will return an error if it was unable to set this + // breakpoint. We need to differentiate between a error specific to placing this breakpoint + // or if we have learned that this breakpoint type is unsupported. To do this, we + // must test the support boolean for this breakpoint type to see if it now indicates that + // this breakpoint type is unsupported. If they are still supported then we should return + // with the error code. If they are now unsupported, then we would like to fall through + // and try another form of breakpoint. + if (m_gdb_comm.SupportsGDBStoppointPacket(eBreakpointSoftware)) + return error; + + // We reach here when software breakpoints have been found to be unsupported. For future + // calls to set a breakpoint, we will not attempt to set a breakpoint with a type that is + // known not to be supported. + if (log) + log->Printf("Software breakpoints are unsupported"); + + // So we will fall through and try a hardware breakpoint + } + + // The process of setting a hardware breakpoint is much the same as above. We check the + // supported boolean for this breakpoint type, and if it is thought to be supported then we + // will try to set this breakpoint with a hardware breakpoint. + if (m_gdb_comm.SupportsGDBStoppointPacket(eBreakpointHardware)) + { + // Try to send off a hardware breakpoint packet ($Z1) + if (m_gdb_comm.SendGDBStoppointTypePacket(eBreakpointHardware, true, addr, bp_op_size) == 0) { - // Try and set hardware breakpoint, and if that fails, fall through - // and set a software breakpoint? - if (m_gdb_comm.SupportsGDBStoppointPacket (eBreakpointHardware)) - { - if (m_gdb_comm.SendGDBStoppointTypePacket(eBreakpointHardware, true, addr, bp_op_size) == 0) - { - bp_site->SetEnabled(true); - bp_site->SetType (BreakpointSite::eHardware); - } - else - { - error.SetErrorString("failed to set hardware breakpoint (hardware breakpoint resources might be exhausted or unavailable)"); - } - } - else - { - error.SetErrorString("hardware breakpoints are not supported"); - } + // The breakpoint was placed successfully + bp_site->SetEnabled(true); + bp_site->SetType(BreakpointSite::eHardware); return error; } - else if (m_gdb_comm.SupportsGDBStoppointPacket (eBreakpointSoftware)) + + // Check if the error was something other then an unsupported breakpoint type + if (m_gdb_comm.SupportsGDBStoppointPacket(eBreakpointHardware)) { - if (m_gdb_comm.SendGDBStoppointTypePacket(eBreakpointSoftware, true, addr, bp_op_size) == 0) - { - bp_site->SetEnabled(true); - bp_site->SetType (BreakpointSite::eExternal); - return error; - } + // Unable to set this hardware breakpoint + error.SetErrorString("failed to set hardware breakpoint (hardware breakpoint resources might be exhausted or unavailable)"); + return error; } - return EnableSoftwareBreakpoint (bp_site); + // We will reach here when the stub gives an unsported response to a hardware breakpoint + if (log) + log->Printf("Hardware breakpoints are unsupported"); + + // Finally we will falling through to a #trap style breakpoint } - if (log) + // Don't fall through when hardware breakpoints were specifically requested + if (bp_site->HardwareRequired()) { - const char *err_string = error.AsCString(); - log->Printf ("ProcessGDBRemote::EnableBreakpointSite () error for breakpoint at 0x%8.8" PRIx64 ": %s", - bp_site->GetLoadAddress(), - err_string ? err_string : "NULL"); + error.SetErrorString("hardware breakpoints are not supported"); + return error; } - // We shouldn't reach here on a successful breakpoint enable... - if (error.Success()) - error.SetErrorToGenericError(); - return error; + + // As a last resort we want to place a manual breakpoint. An instruction + // is placed into the process memory using memory write packets. + return EnableSoftwareBreakpoint(bp_site); } Error @@ -2399,7 +2435,7 @@ ProcessGDBRemote::DisableBreakpointSite (BreakpointSite *bp_site) break; case BreakpointSite::eHardware: - if (m_gdb_comm.SendGDBStoppointTypePacket(eBreakpointSoftware, false, addr, bp_op_size)) + if (m_gdb_comm.SendGDBStoppointTypePacket(eBreakpointHardware, false, addr, bp_op_size)) error.SetErrorToGenericError(); break; |
