[Lldb-commits] [lldb] 7ed185a - [lldb] Expose language plugin commands based based on language of current frame (#136766)
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lldb-commits at lists.llvm.org
Wed May 28 11:05:00 PDT 2025
Author: Dave Lee
Date: 2025-05-28T11:04:57-07:00
New Revision: 7ed185a8f2b9f2436db1ccd82964424f641917e9
URL: https://github.com/llvm/llvm-project/commit/7ed185a8f2b9f2436db1ccd82964424f641917e9
DIFF: https://github.com/llvm/llvm-project/commit/7ed185a8f2b9f2436db1ccd82964424f641917e9.diff
LOG: [lldb] Expose language plugin commands based based on language of current frame (#136766)
Use the current frame's language to lookup commands provided by language plugins.
This means commands like `language {objc,cplusplus} <command>` can be used directly, without using the `language <lang>` prefix.
For example, when stopped on a C++ frame, `demangle _Z1fv` will run `language cplusplus demangle _Z1fv`.
rdar://149882520
Added:
lldb/test/API/commands/command/language/Makefile
lldb/test/API/commands/command/language/TestFrameLanguageCommands.py
lldb/test/API/commands/command/language/commands.py
lldb/test/API/commands/command/language/lib.cpp
lldb/test/API/commands/command/language/main.mm
Modified:
lldb/include/lldb/Interpreter/CommandInterpreter.h
lldb/source/Commands/CommandObjectLanguage.cpp
lldb/source/Interpreter/CommandInterpreter.cpp
Removed:
################################################################################
diff --git a/lldb/include/lldb/Interpreter/CommandInterpreter.h b/lldb/include/lldb/Interpreter/CommandInterpreter.h
index 724d88d65f6ac..26e0767951e7f 100644
--- a/lldb/include/lldb/Interpreter/CommandInterpreter.h
+++ b/lldb/include/lldb/Interpreter/CommandInterpreter.h
@@ -730,6 +730,12 @@ class CommandInterpreter : public Broadcaster,
bool EchoCommandNonInteractive(llvm::StringRef line,
const Flags &io_handler_flags) const;
+ /// Return the language specific command object for the current frame.
+ ///
+ /// For example, when stopped on a C++ frame, this returns the command object
+ /// for "language cplusplus" (`CommandObjectMultiwordItaniumABI`).
+ lldb::CommandObjectSP GetFrameLanguageCommand() const;
+
// A very simple state machine which models the command handling transitions
enum class CommandHandlingState {
eIdle,
diff --git a/lldb/source/Commands/CommandObjectLanguage.cpp b/lldb/source/Commands/CommandObjectLanguage.cpp
index 925db599e4abb..7272241551058 100644
--- a/lldb/source/Commands/CommandObjectLanguage.cpp
+++ b/lldb/source/Commands/CommandObjectLanguage.cpp
@@ -21,6 +21,18 @@ CommandObjectLanguage::CommandObjectLanguage(CommandInterpreter &interpreter)
"language <language-name> <subcommand> [<subcommand-options>]") {
// Let the LanguageRuntime populates this command with subcommands
LanguageRuntime::InitializeCommands(this);
+ SetHelpLong(
+ R"(
+Language specific subcommands may be used directly (without the `language
+<language-name>` prefix), when stopped on a frame written in that language. For
+example, from a C++ frame, users may run `demangle` directly, instead of
+`language cplusplus demangle`.
+
+Language specific subcommands are only available when the command name cannot be
+misinterpreted. Take the `demangle` command for example, if a Python command
+named `demangle-tree` were loaded, then the invocation `demangle` would run
+`demangle-tree`, not `language cplusplus demangle`.
+ )");
}
CommandObjectLanguage::~CommandObjectLanguage() = default;
diff --git a/lldb/source/Interpreter/CommandInterpreter.cpp b/lldb/source/Interpreter/CommandInterpreter.cpp
index 34749d890bf03..4f9ae104dedea 100644
--- a/lldb/source/Interpreter/CommandInterpreter.cpp
+++ b/lldb/source/Interpreter/CommandInterpreter.cpp
@@ -1018,6 +1018,28 @@ CommandInterpreter::VerifyUserMultiwordCmdPath(Args &path, bool leaf_is_command,
return cur_as_multi;
}
+CommandObjectSP CommandInterpreter::GetFrameLanguageCommand() const {
+ auto frame_sp = GetExecutionContext().GetFrameSP();
+ if (!frame_sp)
+ return {};
+ auto frame_language =
+ Language::GetPrimaryLanguage(frame_sp->GuessLanguage().AsLanguageType());
+
+ auto it = m_command_dict.find("language");
+ if (it == m_command_dict.end())
+ return {};
+ // The root "language" command.
+ CommandObjectSP language_cmd_sp = it->second;
+
+ auto *plugin = Language::FindPlugin(frame_language);
+ if (!plugin)
+ return {};
+ // "cplusplus", "objc", etc.
+ auto lang_name = plugin->GetPluginName();
+
+ return language_cmd_sp->GetSubcommandSPExact(lang_name);
+}
+
CommandObjectSP
CommandInterpreter::GetCommandSP(llvm::StringRef cmd_str, bool include_aliases,
bool exact, StringList *matches,
@@ -1136,7 +1158,34 @@ CommandInterpreter::GetCommandSP(llvm::StringRef cmd_str, bool include_aliases,
else
return user_match_sp;
}
- } else if (matches && command_sp) {
+ }
+
+ // When no single match is found, attempt to resolve the command as a language
+ // plugin subcommand.
+ if (!command_sp) {
+ // The `language` subcommand ("language objc", "language cplusplus", etc).
+ CommandObjectMultiword *lang_subcmd = nullptr;
+ if (auto lang_subcmd_sp = GetFrameLanguageCommand()) {
+ lang_subcmd = lang_subcmd_sp->GetAsMultiwordCommand();
+ command_sp = lang_subcmd_sp->GetSubcommandSPExact(cmd_str);
+ }
+
+ if (!command_sp && !exact && lang_subcmd) {
+ StringList lang_matches;
+ AddNamesMatchingPartialString(lang_subcmd->GetSubcommandDictionary(),
+ cmd_str, lang_matches, descriptions);
+ if (matches)
+ matches->AppendList(lang_matches);
+ if (lang_matches.GetSize() == 1) {
+ const auto &lang_dict = lang_subcmd->GetSubcommandDictionary();
+ auto pos = lang_dict.find(lang_matches[0]);
+ if (pos != lang_dict.end())
+ return pos->second;
+ }
+ }
+ }
+
+ if (matches && command_sp) {
matches->AppendString(cmd_str);
if (descriptions)
descriptions->AppendString(command_sp->GetHelp());
diff --git a/lldb/test/API/commands/command/language/Makefile b/lldb/test/API/commands/command/language/Makefile
new file mode 100644
index 0000000000000..2d5049417ee70
--- /dev/null
+++ b/lldb/test/API/commands/command/language/Makefile
@@ -0,0 +1,4 @@
+OBJCXX_SOURCES := main.mm
+CXX_SOURCES := lib.cpp
+LD_EXTRAS := -lobjc
+include Makefile.rules
diff --git a/lldb/test/API/commands/command/language/TestFrameLanguageCommands.py b/lldb/test/API/commands/command/language/TestFrameLanguageCommands.py
new file mode 100644
index 0000000000000..ff00c9d7cb3f6
--- /dev/null
+++ b/lldb/test/API/commands/command/language/TestFrameLanguageCommands.py
@@ -0,0 +1,61 @@
+import lldb
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test.decorators import *
+import lldbsuite.test.lldbutil as lldbutil
+
+
+class TestCase(TestBase):
+ def test(self):
+ self.build()
+ _, _, thread, _ = lldbutil.run_to_source_breakpoint(
+ self, "break here", lldb.SBFileSpec("lib.cpp")
+ )
+
+ frame = thread.selected_frame
+ self.assertEqual(frame.GuessLanguage(), lldb.eLanguageTypeC_plus_plus_11)
+ self.assertEqual(frame.name, "f()")
+
+ # Test `help`.
+ self.expect(
+ "help demangle",
+ substrs=[
+ "Demangle a C++ mangled name.",
+ "Syntax: language cplusplus demangle [<mangled-name> ...]",
+ ],
+ )
+
+ # Run a `language cplusplus` command.
+ self.expect("demangle _Z1fv", startstr="_Z1fv ---> f()")
+ # Test prefix matching.
+ self.expect("dem _Z1fv", startstr="_Z1fv ---> f()")
+
+ # Select the objc caller.
+ self.runCmd("up")
+ frame = thread.selected_frame
+ self.assertEqual(frame.GuessLanguage(), lldb.eLanguageTypeObjC_plus_plus)
+ self.assertEqual(frame.name, "main")
+
+ # Ensure `demangle` doesn't resolve from the objc frame.
+ self.expect("help demangle", error=True)
+
+ # Run a `language objc` command.
+ self.expect(
+ "tagged-pointer",
+ substrs=[
+ "Commands for operating on Objective-C tagged pointers.",
+ "Syntax: tagged-pointer <subcommand> [<subcommand-options>]",
+ "The following subcommands are supported:",
+ "info -- Dump information on a tagged pointer.",
+ ],
+ )
+
+ # To ensure compatability with existing scripts, a language specific
+ # command must not be invoked if another command (such as a python
+ # command) has the language specific command name as its prefix.
+ #
+ # For example, this test loads a `tagged-pointer-collision` command. A
+ # script could exist that invokes this command using its prefix
+ # `tagged-pointer`, under the assumption that "tagged-pointer" uniquely
+ # identifies the python command `tagged-pointer-collision`.
+ self.runCmd("command script import commands.py")
+ self.expect("tagged-pointer", startstr="ran tagged-pointer-collision")
diff --git a/lldb/test/API/commands/command/language/commands.py b/lldb/test/API/commands/command/language/commands.py
new file mode 100644
index 0000000000000..e4215317f3c3e
--- /dev/null
+++ b/lldb/test/API/commands/command/language/commands.py
@@ -0,0 +1,6 @@
+import lldb
+
+
+ at lldb.command("tagged-pointer-collision")
+def noop(dbg, cmdstr, ctx, result, _):
+ print("ran tagged-pointer-collision", file=result)
diff --git a/lldb/test/API/commands/command/language/lib.cpp b/lldb/test/API/commands/command/language/lib.cpp
new file mode 100644
index 0000000000000..225d2992d36d2
--- /dev/null
+++ b/lldb/test/API/commands/command/language/lib.cpp
@@ -0,0 +1,3 @@
+#include <stdio.h>
+extern void f();
+void f() { puts("break here"); }
diff --git a/lldb/test/API/commands/command/language/main.mm b/lldb/test/API/commands/command/language/main.mm
new file mode 100644
index 0000000000000..93b87eb4d3176
--- /dev/null
+++ b/lldb/test/API/commands/command/language/main.mm
@@ -0,0 +1,6 @@
+extern void f();
+
+int main() {
+ f();
+ return 0;
+}
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