[Lldb-commits] [lldb] [lldb] Fix a quirk in SBValue::GetDescription (PR #75793)

[Pavel Labath via lldb-commits]

https://github.com/labath created https://github.com/llvm/llvm-project/pull/75793

The function was using the default version of ValueObject::Dump, which has a default of using the synthetic-ness of the top-level value for determining whether to print _all_ values as synthetic. This resulted in some unusual behavior, where e.g. a std::vector is stringified as synthetic if its dumped as the top level object, but in its raw form if it is a member of a struct without a pretty printer.

The SBValue class already has properties which determine whether one should be looking at the synthetic view of the object (and also whether to use dynamic types), so it seems more natural to use that.

>From 0c727d2c339893b439c5a17cf9ba6ae03b5cf87e Mon Sep 17 00:00:00 2001
From: Pavel Labath <pavel at labath.sk>
Date: Mon, 18 Dec 2023 14:25:42 +0100
Subject: [PATCH] [lldb] Fix a quirk in SBValue::GetDescription

The function was using the default version of ValueObject::Dump, which
has a default of using the synthetic-ness of the top-level value for
determining whether to print _all_ values as synthetic. This resulted in
some unusual behavior, where e.g. a std::vector is stringified as
synthetic if its dumped as the top level object, but in its raw form if
it is a member of a struct without a pretty printer.

The SBValue class already has properties which determine whether one
should be looking at the synthetic view of the object (and also whether
to use dynamic types), so it seems more natural to use that.
---
 lldb/source/API/SBValue.cpp                   | 11 ++++++++---
 .../API/python_api/sbvalue_synthetic/Makefile |  3 +++
 .../sbvalue_synthetic/TestSBValueSynthetic.py | 19 +++++++++++++++++++
 .../API/python_api/sbvalue_synthetic/main.cpp | 11 +++++++++++
 4 files changed, 41 insertions(+), 3 deletions(-)
 create mode 100644 lldb/test/API/python_api/sbvalue_synthetic/Makefile
 create mode 100644 lldb/test/API/python_api/sbvalue_synthetic/TestSBValueSynthetic.py
 create mode 100644 lldb/test/API/python_api/sbvalue_synthetic/main.cpp

diff --git a/lldb/source/API/SBValue.cpp b/lldb/source/API/SBValue.cpp
index 34d01d759ba55a..89d26a1fbe2824 100644
--- a/lldb/source/API/SBValue.cpp
+++ b/lldb/source/API/SBValue.cpp
@@ -24,6 +24,7 @@
 #include "lldb/Core/ValueObject.h"
 #include "lldb/Core/ValueObjectConstResult.h"
 #include "lldb/DataFormatters/DataVisualization.h"
+#include "lldb/DataFormatters/DumpValueObjectOptions.h"
 #include "lldb/Symbol/Block.h"
 #include "lldb/Symbol/ObjectFile.h"
 #include "lldb/Symbol/Type.h"
@@ -1209,10 +1210,14 @@ bool SBValue::GetDescription(SBStream &description) {
 
   ValueLocker locker;
   lldb::ValueObjectSP value_sp(GetSP(locker));
-  if (value_sp)
-    value_sp->Dump(strm);
-  else
+  if (value_sp) {
+    DumpValueObjectOptions options;
+    options.SetUseDynamicType(m_opaque_sp->GetUseDynamic());
+    options.SetUseSyntheticValue(m_opaque_sp->GetUseSynthetic());
+    value_sp->Dump(strm, options);
+  } else {
     strm.PutCString("No value");
+  }
 
   return true;
 }
diff --git a/lldb/test/API/python_api/sbvalue_synthetic/Makefile b/lldb/test/API/python_api/sbvalue_synthetic/Makefile
new file mode 100644
index 00000000000000..99998b20bcb050
--- /dev/null
+++ b/lldb/test/API/python_api/sbvalue_synthetic/Makefile
@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+
+include Makefile.rules
diff --git a/lldb/test/API/python_api/sbvalue_synthetic/TestSBValueSynthetic.py b/lldb/test/API/python_api/sbvalue_synthetic/TestSBValueSynthetic.py
new file mode 100644
index 00000000000000..5dcf3c1a9c6c44
--- /dev/null
+++ b/lldb/test/API/python_api/sbvalue_synthetic/TestSBValueSynthetic.py
@@ -0,0 +1,19 @@
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class TestSBValueSynthetic(TestBase):
+    NO_DEBUG_INFO_TESTCASE = True
+
+    def test_str(self):
+        self.build()
+        lldbutil.run_to_source_breakpoint(
+            self, "break here", lldb.SBFileSpec("main.cpp")
+        )
+
+        vector = self.frame().FindVariable("vector")
+        has_vector = self.frame().FindVariable("has_vector")
+        self.expect(str(vector), exe=False, substrs=["42", "47"])
+        self.expect(str(has_vector), exe=False, substrs=["42", "47"])
diff --git a/lldb/test/API/python_api/sbvalue_synthetic/main.cpp b/lldb/test/API/python_api/sbvalue_synthetic/main.cpp
new file mode 100644
index 00000000000000..e6b6ec50f307f8
--- /dev/null
+++ b/lldb/test/API/python_api/sbvalue_synthetic/main.cpp
@@ -0,0 +1,11 @@
+#include <vector>
+
+struct HasVector {
+  std::vector<int> v;
+};
+
+int main() {
+  std::vector<int> vector = {42, 47};
+  HasVector has_vector = {vector};
+  return 0; // break here
+}