[Lldb-commits] [lldb] Support disassembling RISC-V proprietary instructions (PR #145793)

[via lldb-commits]

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+"""
+Defines a command, fdis, that does filtered disassembly. The command does the
+lldb disassemble command with -b and any other arguments passed in, and
+pipes that through a provided filter program.
+
+The intention is to support disassembly of RISC-V proprietary instructions.
+This is handled with llvm-objdump by piping the output of llvm-objdump through
+a filter program. This script is intended to mimic that workflow.
+"""
+
+import lldb
+import subprocess
+
+filter_program = "crustfilt"
+
+def __lldb_init_module(debugger, dict):
+    debugger.HandleCommand(
+        'command script add -f filter_disasm.fdis fdis')
+    print("Disassembly filter command (fdis) loaded")
+    print("Filter program set to %s" % filter_program)
+
+
+def fdis(debugger, args, result, dict):
+    """
+  Call the built in disassembler, then pass its output to a filter program
+  to add in disassembly for hidden opcodes.
+  Except for get and set, use the fdis command like the disassemble command.
+  By default, the filter program is crustfilt, from
+  https://github.com/quic/crustfilt . This can be changed by changing
+  the global variable filter_program.
+
+  Usage:
+    fdis [[get] [set <program>] [<disassembly options>]]
+
+    Choose one of the following:
+        get
+            Gets the current filter program
+
+        set <program>
+            Sets the current filter program. This can be an executable, which
+            will be found on PATH, or an absolute path.
+
+        <disassembly options>
+            If the first argument is not get or set, the args will be passed
+            to the disassemble command as is.
+
+    """
+
+    global filter_program
+    args_list = args.split(' ')
+    result.Clear()
+
+    if len(args_list) == 1 and args_list[0] == 'get':
+        result.PutCString(filter_program)
+        result.SetStatus(lldb.eReturnStatusSuccessFinishResult)
+        return
+
+    if len(args_list) == 2 and args_list[0] == 'set':
+        filter_program = args_list[1]
+        result.PutCString("Filter program set to %s" % filter_program)
+        result.SetStatus(lldb.eReturnStatusSuccessFinishResult)
+        return
+
+    res = lldb.SBCommandReturnObject()
+    debugger.GetCommandInterpreter().HandleCommand('disassemble -b ' + args, res)
+    if (len(res.GetError()) > 0):
+        result.SetError(res.GetError())
+        result.SetStatus(lldb.eReturnStatusFailed)
+        return
+    output = res.GetOutput()
+
+    try:
+        proc = subprocess.run([filter_program], capture_output=True, text=True, input=output)
+    except (subprocess.SubprocessError, OSError) as e:
+        result.PutCString("Error occurred. Original disassembly:\n\n" + output)
+        result.SetError(str(e))
+        result.SetStatus(lldb.eReturnStatusFailed)
+        return
+
+    print(proc.stderr)
+    if proc.stderr:
+        pass
+        #result.SetError(proc.stderr)
+        #result.SetStatus(lldb.eReturnStatusFailed)
----------------
tedwoodward wrote:

I'm not sure the presence of data on stderr means a failure. I'll look into error handling more.

https://github.com/llvm/llvm-project/pull/145793