[Lldb-commits] [PATCH] D109272: [lldb] [gdb-remote] Try using <architecture/> for remote arch unconditionally

[Michał Górny via Phabricator via lldb-commits]

mgorny created this revision.
mgorny added reviewers: krytarowski, labath, jasonmolenda, JDevlieghere, emaste.
Herald added a subscriber: kristof.beyls.
mgorny requested review of this revision.

Try determining the process architecture from <architecture/> tag
unconditionally, rather than for very specific cases.  Generic gdbserver
implementations do not support LLDB-specific packets used to determine
the process architecture, therefore this fallback is necessary to
support architecture-specific behavior on these targets.  Rather than
maintaining a mapping of all known architectures, just try mapping
the GDB values into triplets, as that is going to work most of the time.

This change is confirmed to fix LLDB against gdbserver when debugging
i386 and aarch64 executables.


https://reviews.llvm.org/D109272

Files:
  lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp


Index: lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
===================================================================
--- lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -4661,24 +4661,22 @@
       }
     }
 
-    // If the target.xml includes an architecture entry like
+    // gdbserver does not implement the LLDB packets used to determine host
+    // or process architecture.  If that is the case, attempt to use
+    // the <architecture/> field from target.xml, e.g.:
+    //
     //   <architecture>i386:x86-64</architecture> (seen from VMWare ESXi)
-    //   <architecture>arm</architecture> (seen from Segger JLink on unspecified arm board)
-    // use that if we don't have anything better.
+    //   <architecture>arm</architecture> (seen from Segger JLink on unspecified
+    //   arm board)
     if (!arch_to_use.IsValid() && !target_info.arch.empty()) {
-      if (target_info.arch == "i386:x86-64") {
-        // We don't have any information about vendor or OS.
-        arch_to_use.SetTriple("x86_64--");
-        GetTarget().MergeArchitecture(arch_to_use);
-      }
+      // We don't have any information about vendor or OS.
+      arch_to_use.SetTriple(llvm::StringSwitch<std::string>(target_info.arch)
+                                .Case("i386:x86-64", "x86_64")
+                                .Default(target_info.arch) +
+                            "--");
 
-      // SEGGER J-Link jtag boards send this very-generic arch name,
-      // we'll need to use this if we have absolutely nothing better
-      // to work with or the register definitions won't be accepted.
-      if (target_info.arch == "arm") {
-        arch_to_use.SetTriple("arm--");
+      if (arch_to_use.IsValid())
         GetTarget().MergeArchitecture(arch_to_use);
-      }
     }
 
     if (arch_to_use.IsValid()) {


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