[lldb][Expression] Add API to set/get language-specific expression options #179208

Michael137 · 2026-02-02T11:15:10Z

The motivation here is that we don't want to pollute the SBAPI with getters/setters for expression evaluation options that only apply to a single language. The ultimate goal would be to have plugins register additional options to the expression command when the plugin is loaded. This patch only provides the minimal SBExpressionOptions interface to set an option with an arbitrary name, which the language plugin knows how to interpret. The underlying options dictionary is an StructuredData::Dictionary so we can map strings to values of any type. But the SBAPI just exposes setting a boolean value. Future overloads of SetLanguageOption can provide setters for more types.

The boolean setter/getter will be used for the C++-specific option being introduced in: #177926

…tions The motivation here is that we don't want to pollute the SBAPI with getters/setters for expression evaluation options that only apply to a single language. The ultimate goal would be to have plugins register additional options to the `expression` command when the plugin is loaded. This patch only provides the minimal `SBExpressionOptions` interface to set an option with an arbitrary name, which the language plugin knows how to interpret. The underlying options dictionary is an `StructuredData::Dictionary` so we can map strings to values of any type. But the SBAPI just exposes setting a boolean value. Future overloads of `SetLanguageOption` can provide setters for more types. The boolean setter/getter will be used for the C++-specific option being introduced in: llvm#177926

Michael137 · 2026-02-02T11:15:23Z

@adrian-prantl is this what you had in mind in
#177926 (comment)?

llvmbot · 2026-02-02T11:15:49Z

@llvm/pr-subscribers-lldb

Author: Michael Buch (Michael137)

Changes

The motivation here is that we don't want to pollute the SBAPI with getters/setters for expression evaluation options that only apply to a single language. The ultimate goal would be to have plugins register additional options to the expression command when the plugin is loaded. This patch only provides the minimal SBExpressionOptions interface to set an option with an arbitrary name, which the language plugin knows how to interpret. The underlying options dictionary is an StructuredData::Dictionary so we can map strings to values of any type. But the SBAPI just exposes setting a boolean value. Future overloads of SetLanguageOption can provide setters for more types.

The boolean setter/getter will be used for the C++-specific option being introduced in: #177926

Full diff: https://github.com/llvm/llvm-project/pull/179208.diff

6 Files Affected:

(modified) lldb/bindings/interface/SBExpressionOptionsDocstrings.i (+6)
(modified) lldb/include/lldb/API/SBExpressionOptions.h (+5)
(modified) lldb/include/lldb/Target/Target.h (+40-2)
(modified) lldb/source/API/SBExpressionOptions.cpp (+12)
(modified) lldb/test/API/commands/expression/options/TestExprOptions.py (+24-1)
(modified) lldb/unittests/Expression/ExpressionTest.cpp (+25)

diff --git a/lldb/bindings/interface/SBExpressionOptionsDocstrings.i b/lldb/bindings/interface/SBExpressionOptionsDocstrings.i
index 2bb562778db79..a6de6f034bd7a 100644
--- a/lldb/bindings/interface/SBExpressionOptionsDocstrings.i
+++ b/lldb/bindings/interface/SBExpressionOptionsDocstrings.i
@@ -61,3 +61,9 @@
 
 %feature("docstring", "Sets whether to JIT an expression if it cannot be interpreted."
 ) lldb::SBExpressionOptions::SetAllowJIT;
+
+%feature("docstring", "Sets language-plugin specific boolean option for expression evaluation."
+) lldb::SBExpressionOptions::SetLanguageOption;
+
+%feature("docstring", "Gets language-plugin specific boolean option for expression evaluation."
+) lldb::SBExpressionOptions::GetLanguageOptionAsBoolean;
diff --git a/lldb/include/lldb/API/SBExpressionOptions.h b/lldb/include/lldb/API/SBExpressionOptions.h
index a9e929a4c0bd9..6f7bd53d6fa70 100644
--- a/lldb/include/lldb/API/SBExpressionOptions.h
+++ b/lldb/include/lldb/API/SBExpressionOptions.h
@@ -11,6 +11,7 @@
 
 #include "lldb/API/SBDefines.h"
 #include "lldb/API/SBLanguages.h"
+#include "lldb/API/SBStructuredData.h"
 
 #include <vector>
 
@@ -107,6 +108,10 @@ class LLDB_API SBExpressionOptions {
   // Sets whether we will JIT an expression if it cannot be interpreted
   void SetAllowJIT(bool allow);
 
+  bool GetLanguageOptionAsBoolean(const char *option_name) const;
+ 
+  void SetLanguageOption(const char *option_name, bool value);
+
 protected:
   lldb_private::EvaluateExpressionOptions *get() const;
 
diff --git a/lldb/include/lldb/Target/Target.h b/lldb/include/lldb/Target/Target.h
index 812a638910b3b..2583c14965e61 100644
--- a/lldb/include/lldb/Target/Target.h
+++ b/lldb/include/lldb/Target/Target.h
@@ -15,6 +15,7 @@
 #include <string>
 #include <vector>
 
+#include "lldb/API/SBStructuredData.h"
 #include "lldb/Breakpoint/BreakpointList.h"
 #include "lldb/Breakpoint/BreakpointName.h"
 #include "lldb/Breakpoint/WatchpointList.h"
@@ -307,6 +308,8 @@ class TargetProperties : public Properties {
 
 class EvaluateExpressionOptions {
 public:
+    EvaluateExpressionOptions() : m_language_options_sp(std::make_shared<StructuredData::Dictionary>()) {}
+
 // MSVC has a bug here that reports C4268: 'const' static/global data
 // initialized with compiler generated default constructor fills the object
 // with zeros. Confirmed that MSVC is *not* zero-initializing, it's just a
@@ -323,8 +326,6 @@ class EvaluateExpressionOptions {
   static constexpr ExecutionPolicy default_execution_policy =
       eExecutionPolicyOnlyWhenNeeded;
 
-  EvaluateExpressionOptions() = default;
-
   ExecutionPolicy GetExecutionPolicy() const { return m_execution_policy; }
 
   void SetExecutionPolicy(ExecutionPolicy policy = eExecutionPolicyAlways) {
@@ -481,7 +482,40 @@ class EvaluateExpressionOptions {
 
   void SetIsForUtilityExpr(bool b) { m_running_utility_expression = b; }
 
+  /// Set language-plugin specific option called \c option_name to
+  /// the specified boolean \c value.
+  void SetLanguageOption(llvm::StringRef option_name, bool value) {
+    if (option_name.empty())
+      return;
+
+    GetLanguageOptions().AddBooleanItem(option_name, value);
+  }
+
+  /// Get the language-plugin specific boolean option called \c option_name.
+  ///
+  /// If the option doesn't exist or is not a boolean option, returns false.
+  /// Otherwise returns the boolean value of the option.
+  bool GetLanguageOptionAsBoolean(llvm::StringRef option_name) const {
+    bool result;
+    if (!GetLanguageOptions().GetValueForKeyAsBoolean(option_name, result))
+      return false;
+
+    return result;
+  }
+
 private:
+  const StructuredData::Dictionary &GetLanguageOptions() const {
+    assert (m_language_options_sp);
+
+    return *m_language_options_sp;
+  }
+
+  StructuredData::Dictionary &GetLanguageOptions() {
+    assert (m_language_options_sp);
+
+    return *m_language_options_sp;
+  }
+
   ExecutionPolicy m_execution_policy = default_execution_policy;
   SourceLanguage m_language;
   std::string m_prefix;
@@ -514,6 +548,10 @@ class EvaluateExpressionOptions {
   mutable std::string m_pound_line_file;
   mutable uint32_t m_pound_line_line = 0;
 
+  /// Dictionary mapping names of language-plugin specific options
+  /// to values.
+  StructuredData::DictionarySP m_language_options_sp = nullptr;
+
   /// During expression evaluation, any SymbolContext in this list will be
   /// used for symbol/function lookup before any other context (except for
   /// the module corresponding to the current frame).
diff --git a/lldb/source/API/SBExpressionOptions.cpp b/lldb/source/API/SBExpressionOptions.cpp
index 15ed403eaaea1..e28c7ebfd0133 100644
--- a/lldb/source/API/SBExpressionOptions.cpp
+++ b/lldb/source/API/SBExpressionOptions.cpp
@@ -256,6 +256,18 @@ void SBExpressionOptions::SetAllowJIT(bool allow) {
                                         : eExecutionPolicyNever);
 }
 
+bool SBExpressionOptions::GetLanguageOptionAsBoolean(const char *option_name) const {
+  LLDB_INSTRUMENT_VA(this, option_name);
+
+  return m_opaque_up->GetLanguageOptionAsBoolean(option_name);
+}
+
+void SBExpressionOptions::SetLanguageOption(const char *option_name, bool value) {
+  LLDB_INSTRUMENT_VA(this, option_name, value);
+
+  m_opaque_up->SetLanguageOption(option_name, value);
+ }
+
 EvaluateExpressionOptions *SBExpressionOptions::get() const {
   return m_opaque_up.get();
 }
diff --git a/lldb/test/API/commands/expression/options/TestExprOptions.py b/lldb/test/API/commands/expression/options/TestExprOptions.py
index 01899f3b97cf4..96bb4742a1a10 100644
--- a/lldb/test/API/commands/expression/options/TestExprOptions.py
+++ b/lldb/test/API/commands/expression/options/TestExprOptions.py
@@ -7,7 +7,6 @@
   Test expression command options.
 """
 
-
 import lldb
 import lldbsuite.test.lldbutil as lldbutil
 from lldbsuite.test.decorators import *
@@ -85,3 +84,27 @@ def test_expr_options_lang(self):
         val = frame.EvaluateExpression("id == 0", options)
         self.assertTrue(val.IsValid())
         self.assertFalse(val.GetError().Success())
+
+    def test_expr_options_language_options(self):
+        """Test SetLanguageOption/GetLanguageOption SBAPIs"""
+
+        options = lldb.SBExpressionOptions()
+        self.assertFalse(options.GetLanguageOptionAsBoolean("foo"))
+        self.assertFalse(options.GetLanguageOptionAsBoolean("bar"))
+
+        options.SetLanguageOption("foo", True)
+        options.SetLanguageOption("bar", True)
+        self.assertTrue(options.GetLanguageOptionAsBoolean("foo"))
+        self.assertTrue(options.GetLanguageOptionAsBoolean("bar"))
+
+        options.SetLanguageOption("foo", False)
+        options.SetLanguageOption("bar", False)
+        self.assertFalse(options.GetLanguageOptionAsBoolean("foo"))
+        self.assertFalse(options.GetLanguageOptionAsBoolean("bar"))
+
+        self.assertFalse(options.GetLanguageOptionAsBoolean(""))
+        options.SetLanguageOption("", True)
+        self.assertFalse(options.GetLanguageOptionAsBoolean(""))
+
+        options.SetLanguageOption(None, True)
+        self.assertFalse(options.GetLanguageOptionAsBoolean(None))
diff --git a/lldb/unittests/Expression/ExpressionTest.cpp b/lldb/unittests/Expression/ExpressionTest.cpp
index ceb567c28ab99..4201516dfc820 100644
--- a/lldb/unittests/Expression/ExpressionTest.cpp
+++ b/lldb/unittests/Expression/ExpressionTest.cpp
@@ -10,6 +10,7 @@
 #include "gtest/gtest.h"
 
 #include "TestingSupport/TestUtilities.h"
+#include "lldb/Target/Target.h"
 #include "lldb/Expression/Expression.h"
 #include "llvm/Testing/Support/Error.h"
 
@@ -127,3 +128,27 @@ TEST_P(ExpressionTestFixture, FunctionCallLabel) {
 
 INSTANTIATE_TEST_SUITE_P(FunctionCallLabelTest, ExpressionTestFixture,
                          testing::ValuesIn(g_label_test_cases));
+
+TEST(ExpressionTests, ExpressionOptions_Basic) {
+  EvaluateExpressionOptions options;
+
+  ASSERT_FALSE(options.GetLanguageOptionAsBoolean("foo"));
+  ASSERT_FALSE(options.GetLanguageOptionAsBoolean("bar"));
+
+  options.SetLanguageOption("foo", true);
+  options.SetLanguageOption("bar", true);
+
+  ASSERT_TRUE(options.GetLanguageOptionAsBoolean("foo"));
+  ASSERT_TRUE(options.GetLanguageOptionAsBoolean("bar"));
+
+  options.SetLanguageOption("foo", false);
+  options.SetLanguageOption("bar", false);
+
+  ASSERT_FALSE(options.GetLanguageOptionAsBoolean("foo"));
+  ASSERT_FALSE(options.GetLanguageOptionAsBoolean("bar"));
+
+  // Empty option names not allowed.
+  ASSERT_FALSE(options.GetLanguageOptionAsBoolean(""));
+  options.SetLanguageOption("", true);
+  ASSERT_FALSE(options.GetLanguageOptionAsBoolean(""));
+}

github-actions · 2026-02-02T11:16:51Z

✅ With the latest revision this PR passed the C/C++ code formatter.

lldb/include/lldb/API/SBExpressionOptions.h

bulbazord

lgtm

medismailben · 2026-02-02T19:00:03Z

lldb/include/lldb/API/SBExpressionOptions.h

+  bool GetLanguageOptionAsBoolean(const char *option_name) const;
+
+  void SetLanguageOption(const char *option_name, bool value);
+


it's weird to a getter specifically for boolean options but have the setter name be "generic" but take a boolean argument. I also think this is going to break in Python if you add overloads for the setter with different argument types like void SetLanguageOption(const char *option_name, int value).

Suggested change

bool GetBooleanLanguageOption(const char *option_name) const;

void SetBooleanLanguageOption(const char *option_name, bool value);

Oh my assumption was that we can overload functions. Pretty sure SWIG is capable of it? But do we avoid doing overloads?

You can overload functions. SWIG will handle it correctly with args or kwargs in python.

I think Ismail's point is one of consistency. The getter has Boolean in the name but the setter doesn't (even though the two methods are supposed to be matching). I think changing the setter name would resolve this.

To go further, does GetLanguageOptionAsBoolean mean you can get a non-boolean option value as a boolean? Maybe something like GetBooleanLanguageOption is clearer? To make it matchy-matchy you'd also want SetBooleanLanguageOption.

Sounds good, I'll rename the two as suggested!

adrian-prantl · 2026-02-02T22:50:52Z

lldb/include/lldb/API/SBExpressionOptions.h

  // Sets whether we will JIT an expression if it cannot be interpreted
  void SetAllowJIT(bool allow);

+  bool GetLanguageOptionAsBoolean(const char *option_name) const;


This works — or you could have a function that takes an entire dictionary and leave the AsBoolean stuff to SBStructuredData.

Could work. I just didnt want to have a setter that takes an SBStructuredData because it made things pretty unergonomic. So i just mirrored the setter/getter. But i dont feel strongly about either direction

I'm not sure we want to expose the dictionary to users. Both because that's unergonomic and because what does the dictionary mean? Can I delete elements from it, add elements to it? I think it's better to hide that.

jimingham · 2026-02-02T22:53:21Z

lldb/include/lldb/Target/Target.h

+    if (option_name.empty())
+      return;
+
+    GetLanguageOptions().AddBooleanItem(option_name, value);


Does this just silently fail if the user has mistyped the name of the item?

That doesn't seem very user-friendly, this should return an SBError or something.

We don't have anything in-place to validate whether the option is something that the expression parser will understand. But happy to change the SBAPI setter to return a boolean for now, in case we ever want to/are able to validate the option name

Ended up making it return a llvm::Expected/SBError

jimingham · 2026-02-02T22:54:13Z

lldb/include/lldb/Target/Target.h

+  ///
+  /// If the option doesn't exist or is not a boolean option, returns false.
+  /// Otherwise returns the boolean value of the option.
+  bool GetLanguageOptionAsBoolean(llvm::StringRef option_name) const {


I don't think silently returning false for mistypings is the right API design.

Yea agreed, happy to change it to an llvm::Expected

lldb/test/API/commands/expression/options/TestExprOptions.py

medismailben

LGTM! Thanks!

Michael137 requested review from adrian-prantl and jimingham February 2, 2026 11:15

Michael137 requested a review from JDevlieghere as a code owner February 2, 2026 11:15

llvmbot added the lldb label Feb 2, 2026

fixup! clang-format

f1d8205

Michael137 commented Feb 2, 2026

View reviewed changes

lldb/include/lldb/API/SBExpressionOptions.h Outdated Show resolved Hide resolved

Michael137 added 2 commits February 2, 2026 12:08

fixup! remove redundant include

e468faa

fixup! include correct header

a84c451

bulbazord approved these changes Feb 2, 2026

View reviewed changes

medismailben requested changes Feb 2, 2026

View reviewed changes

adrian-prantl reviewed Feb 2, 2026

View reviewed changes

jimingham reviewed Feb 2, 2026

View reviewed changes

Michael137 added 4 commits February 3, 2026 07:59

fixup! move definition to Target.cpp

2deb903

fixup! rename APIs; add SBError to APIs

e1591e3

fixup! rename APIs; add SBError to APIs

1a0276b

fixup! add unit-tests

dc3a7ef

Michael137 commented Feb 3, 2026

View reviewed changes

lldb/test/API/commands/expression/options/TestExprOptions.py Outdated Show resolved Hide resolved

fixup! fix test comment

6a3032a

medismailben approved these changes Feb 3, 2026

View reviewed changes

		bool GetLanguageOptionAsBoolean(const char *option_name) const;

		void SetLanguageOption(const char *option_name, bool value);


	bool GetBooleanLanguageOption(const char *option_name) const;

	void SetBooleanLanguageOption(const char *option_name, bool value);

[lldb][Expression] Add API to set/get language-specific expression options #179208

Are you sure you want to change the base?

[lldb][Expression] Add API to set/get language-specific expression options #179208

Conversation

Michael137 commented Feb 2, 2026

Uh oh!

Michael137 commented Feb 2, 2026

Uh oh!

llvmbot commented Feb 2, 2026

Uh oh!

github-actions bot commented Feb 2, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Uh oh!

bulbazord left a comment

Choose a reason for hiding this comment

Uh oh!

medismailben Feb 2, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Michael137 Feb 2, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Michael137 Feb 2, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

Uh oh!

medismailben left a comment

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

6 participants

github-actions bot commented Feb 2, 2026 •

edited

Loading

medismailben Feb 2, 2026 •

edited

Loading

Michael137 Feb 2, 2026 •

edited

Loading

Michael137 Feb 2, 2026 •

edited

Loading