[Lldb-commits] [PATCH] D148790: [LLDB] Don't print register fields when asked for a specific format

[David Spickett via Phabricator via lldb-commits]

DavidSpickett created this revision.
Herald added a project: All.
DavidSpickett requested review of this revision.
Herald added a project: LLDB.
Herald added a subscriber: lldb-commits.

Previously if a register had fields we would always print them after the
value if the register was asked for by name.

  (lldb) register read MDCR_EL3
  MDCR_EL3 = 0x00000000
           = {
               ETBAD = 0
  <...>
               RLTE = 0
             }

This can be quite annoying if there are a whole lot of fields but you
want to see the register in a specific format.

  (lldb) register read MDCR_EL3 -f i
  MDCR_EL3 = 0x00000000   unknown     udf    #0x0
           = {
               ETBAD = 0
  <...lots of fields...>

Since it pushes the interesting bit far up the terminal. To solve this,
don't print fields if the user passes --format. If they're doing that
then I think it's reasonable to assume they know what they want and only
want to see that output.

This also gives users a way to silence fields, but not change the format.
By doing `register read foo -f x`. In case they are not useful or perhaps
they are trying to work around a crash.

I have customised the help text for --format for register read to explain this:

  -f <format> ( --format <format> )
       Specify a format to be used for display. If this is set, register fields will not be dispayed.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D148790

Files:
  lldb/include/lldb/Interpreter/OptionGroupFormat.h
  lldb/source/Commands/CommandObjectRegister.cpp
  lldb/test/API/functionalities/gdb_remote_client/TestXMLRegisterFlags.py


Index: lldb/test/API/functionalities/gdb_remote_client/TestXMLRegisterFlags.py
===================================================================
--- lldb/test/API/functionalities/gdb_remote_client/TestXMLRegisterFlags.py
+++ lldb/test/API/functionalities/gdb_remote_client/TestXMLRegisterFlags.py
@@ -410,6 +410,15 @@
 
         self.expect("register read cpsr", substrs=["= (field_2 = 1, field_1 = 1, ...)"])
 
+    @skipIfXmlSupportMissing
+    @skipIfRemote
+    def test_format_disables_flags(self):
+        # If asked for a specific format, don't print flags after it.
+        self.setup_flags_test('<field name="field_0" start="0" end="0"/>')
+
+        self.expect("register read cpsr --format X", substrs=["cpsr = 0xEEEE7777"])
+        self.expect("register read cpsr --format X", substrs=["field_0"], matching=False)
+
     @skipIfXmlSupportMissing
     @skipIfRemote
     def test_xml_includes(self):
Index: lldb/source/Commands/CommandObjectRegister.cpp
===================================================================
--- lldb/source/Commands/CommandObjectRegister.cpp
+++ lldb/source/Commands/CommandObjectRegister.cpp
@@ -44,7 +44,10 @@
             nullptr,
             eCommandRequiresFrame | eCommandRequiresRegContext |
                 eCommandProcessMustBeLaunched | eCommandProcessMustBePaused),
-        m_format_options(eFormatDefault) {
+        m_format_options(eFormatDefault, UINT64_MAX, UINT64_MAX,
+                         {{CommandArgumentType::eArgTypeFormat,
+                           "Specify a format to be used for display. If this "
+                           "is set, register fields will not be dispayed."}}) {
     CommandArgumentEntry arg;
     CommandArgumentData register_arg;
 
@@ -215,8 +218,11 @@
 
           if (const RegisterInfo *reg_info =
                   reg_ctx->GetRegisterInfoByName(arg_str)) {
+            // If they have asked for a specific format don't obscure that by
+            // printing flags afterwards.
+            bool print_flags = !m_format_options.FormatWasSet();
             if (!DumpRegister(m_exe_ctx, strm, *reg_ctx, *reg_info,
-                              /*print_flags=*/true))
+                              print_flags))
               strm.Printf("%-12s = error: unavailable\n", reg_info->name);
           } else {
             result.AppendErrorWithFormat("Invalid register name '%s'.\n",
Index: lldb/include/lldb/Interpreter/OptionGroupFormat.h
===================================================================
--- lldb/include/lldb/Interpreter/OptionGroupFormat.h
+++ lldb/include/lldb/Interpreter/OptionGroupFormat.h
@@ -53,6 +53,8 @@
 
   const OptionValueFormat &GetFormatValue() const { return m_format; }
 
+  bool FormatWasSet() const { return m_format.OptionWasSet(); }
+
   OptionValueUInt64 &GetByteSizeValue() { return m_byte_size; }
 
   const OptionValueUInt64 &GetByteSizeValue() const { return m_byte_size; }


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D148790.515270.patch
Type: text/x-patch
Size: 2930 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/lldb-commits/attachments/20230420/1a212c57/attachment.bin>