[Lldb-commits] [lldb] [lldb][InstrumentationRuntime] Run sanitizer utility expressions as C (PR #172019)

[Michael Buch via lldb-commits]

https://github.com/Michael137 created https://github.com/llvm/llvm-project/pull/172019

The utility expressions in the `InstrumentationRuntime` plugins are just plain C code, but we run them as `ObjC++`. That meant we were doing redundant work (like looking up decls in the Objective-C runtime). The sanitizer tests sporadically time out while looking up function symbols in the Objective-C runtime. This patch switches the expression language to `C`.

Didn't find a great way of testing this other than looking at the expression log.

rdar://165656320

>From 9e1ab2a4b96818953f2562c7e76dffdf2f58c5e2 Mon Sep 17 00:00:00 2001
From: Michael Buch <michaelbuch12 at gmail.com>
Date: Fri, 12 Dec 2025 15:20:20 +0000
Subject: [PATCH] [lldb][InstrumentationRuntime] Run sanitizer utility
 expressions as C

The utility expressions in the `InstrumentationRuntime` plugins are just plain C code, but we run them as `ObjC++`. That meant we were doing redundant work (like looking up decls in the Objective-C runtime). The sanitizer tests sporadically time out while looking up function symbols in the Objective-C runtime. This patch switches the expression language to `C`.

Didn't find a great way of testing this other than looking at the expression log.

rdar://165656320
---
 .../TSan/InstrumentationRuntimeTSan.cpp       |  2 +-
 .../UBSan/InstrumentationRuntimeUBSan.cpp     |  2 +-
 .../Utility/ReportRetriever.cpp               |  2 +-
 .../Shell/Expr/TestASanReportExprNoObjC.test  | 22 ++++++++++++
 .../Shell/Expr/TestTSanReportExprNoObjC.test  | 34 +++++++++++++++++++
 .../Shell/Expr/TestUBSanReportExprNoObjC.test | 24 +++++++++++++
 6 files changed, 83 insertions(+), 3 deletions(-)
 create mode 100644 lldb/test/Shell/Expr/TestASanReportExprNoObjC.test
 create mode 100644 lldb/test/Shell/Expr/TestTSanReportExprNoObjC.test
 create mode 100644 lldb/test/Shell/Expr/TestUBSanReportExprNoObjC.test

diff --git a/lldb/source/Plugins/InstrumentationRuntime/TSan/InstrumentationRuntimeTSan.cpp b/lldb/source/Plugins/InstrumentationRuntime/TSan/InstrumentationRuntimeTSan.cpp
index 498da3ffe5a4a..7db971556a2f0 100644
--- a/lldb/source/Plugins/InstrumentationRuntime/TSan/InstrumentationRuntimeTSan.cpp
+++ b/lldb/source/Plugins/InstrumentationRuntime/TSan/InstrumentationRuntimeTSan.cpp
@@ -319,7 +319,7 @@ StructuredData::ObjectSP InstrumentationRuntimeTSan::RetrieveReportData(
   options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
   options.SetPrefix(thread_sanitizer_retrieve_report_data_prefix);
   options.SetAutoApplyFixIts(false);
-  options.SetLanguage(eLanguageTypeObjC_plus_plus);
+  options.SetLanguage(eLanguageTypeC);
 
   ValueObjectSP main_value;
   ExecutionContext exe_ctx;
diff --git a/lldb/source/Plugins/InstrumentationRuntime/UBSan/InstrumentationRuntimeUBSan.cpp b/lldb/source/Plugins/InstrumentationRuntime/UBSan/InstrumentationRuntimeUBSan.cpp
index 565fd353a98e5..1db85e6815636 100644
--- a/lldb/source/Plugins/InstrumentationRuntime/UBSan/InstrumentationRuntimeUBSan.cpp
+++ b/lldb/source/Plugins/InstrumentationRuntime/UBSan/InstrumentationRuntimeUBSan.cpp
@@ -124,7 +124,7 @@ StructuredData::ObjectSP InstrumentationRuntimeUBSan::RetrieveReportData(
   options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
   options.SetPrefix(ub_sanitizer_retrieve_report_data_prefix);
   options.SetAutoApplyFixIts(false);
-  options.SetLanguage(eLanguageTypeObjC_plus_plus);
+  options.SetLanguage(eLanguageTypeC);
 
   ValueObjectSP main_value;
   ExecutionContext exe_ctx;
diff --git a/lldb/source/Plugins/InstrumentationRuntime/Utility/ReportRetriever.cpp b/lldb/source/Plugins/InstrumentationRuntime/Utility/ReportRetriever.cpp
index 3642cb18c7a97..85852ba40c61c 100644
--- a/lldb/source/Plugins/InstrumentationRuntime/Utility/ReportRetriever.cpp
+++ b/lldb/source/Plugins/InstrumentationRuntime/Utility/ReportRetriever.cpp
@@ -81,7 +81,7 @@ ReportRetriever::RetrieveReportData(const ProcessSP process_sp) {
   options.SetTimeout(process_sp->GetUtilityExpressionTimeout());
   options.SetPrefix(address_sanitizer_retrieve_report_data_prefix);
   options.SetAutoApplyFixIts(false);
-  options.SetLanguage(eLanguageTypeObjC_plus_plus);
+  options.SetLanguage(eLanguageTypeC);
 
   if (auto [m, _] = GetPreferredAsanModule(process_sp->GetTarget()); m) {
     SymbolContextList sc_list;
diff --git a/lldb/test/Shell/Expr/TestASanReportExprNoObjC.test b/lldb/test/Shell/Expr/TestASanReportExprNoObjC.test
new file mode 100644
index 0000000000000..6d50ca264b107
--- /dev/null
+++ b/lldb/test/Shell/Expr/TestASanReportExprNoObjC.test
@@ -0,0 +1,22 @@
+# Tests that the ASan Instrumentation Runtime's utility expression
+# runs as C (and doesn't try to find decls in the ObjC runtime).
+#
+# RUN: split-file %s %t
+# RUN: %clangxx_host -g %t/main.cpp -fsanitize=address -o %t.out
+#
+# RUN: %lldb -s %t/commands.input %t.out -o exit \
+# RUN:     | FileCheck %s --implicit-check-not="AppleObjCVendor"
+
+#--- main.cpp
+
+int main() {
+  int a[5] = {0};
+
+  return a[10];
+}
+
+#--- commands.input
+log enable lldb expr
+run
+
+# CHECK: Picked c for expression evaluation.
diff --git a/lldb/test/Shell/Expr/TestTSanReportExprNoObjC.test b/lldb/test/Shell/Expr/TestTSanReportExprNoObjC.test
new file mode 100644
index 0000000000000..fe1ea3f4f28f4
--- /dev/null
+++ b/lldb/test/Shell/Expr/TestTSanReportExprNoObjC.test
@@ -0,0 +1,34 @@
+# Tests that the TSan Instrumentation Runtime's utility expression
+# runs as C (and doesn't try to find decls in the ObjC runtime).
+#
+# RUN: split-file %s %t
+# RUN: %clangxx_host -std=c++11 -g %t/main.cpp -fsanitize=thread -o %t.out
+#
+# RUN: %lldb -s %t/commands.input %t.out -o exit \
+# RUN:     | FileCheck %s --implicit-check-not="AppleObjCVendor"
+
+#--- main.cpp
+
+#include <thread>
+
+char c = '\0';
+
+void f() {
+  c = 'x';
+}
+
+int main() {
+    std::thread t1(f);
+    std::thread t2(f);
+
+    t1.join();
+    t2.join();
+}
+
+#--- commands.input
+log enable lldb expr
+run
+
+# CHECK: Picked c for expression evaluation.
+
+
diff --git a/lldb/test/Shell/Expr/TestUBSanReportExprNoObjC.test b/lldb/test/Shell/Expr/TestUBSanReportExprNoObjC.test
new file mode 100644
index 0000000000000..39fb9b41a5fed
--- /dev/null
+++ b/lldb/test/Shell/Expr/TestUBSanReportExprNoObjC.test
@@ -0,0 +1,24 @@
+# Tests that the UBSan Instrumentation Runtime's utility expression
+# runs as C (and doesn't try to find decls in the ObjC runtime).
+# Tests that the UBSan Instrumentation Runtime's utility expression
+# runs as C (and doesn't try to find decls in the ObjC runtime).
+#
+# RUN: split-file %s %t
+# RUN: %clangxx_host -g %t/main.cpp -fsanitize=undefined -o %t.out
+#
+# RUN: %lldb -s %t/commands.input %t.out -o exit \
+# RUN:     | FileCheck %s --implicit-check-not="AppleObjCVendor"
+
+#--- main.cpp
+
+int main() {
+  int *p = nullptr;
+
+  return *p;
+}
+
+#--- commands.input
+log enable lldb expr
+run
+
+# CHECK: Picked c for expression evaluation.