[LLDB][PDB] Warn if DIA plugin is requested but not available #160067

Nerixyz · 2025-09-22T10:38:37Z

If LLDB was built without the DIA SDK and the DIA reader is explicitly requested (through LLDB_USE_NATIVE_PDB_READER=0 or settings set plugin.symbol-file.pdb.reader dia), LLDB should print a warning, because it will use the native reader in any case (#159769 (comment)).

This PR adds the warning and a test when LLDB is not built with the SDK on Windows. I don't think any builder runs this configuration, as there are still five failing tests. I tested this locally with and without the SDK.

llvmbot · 2025-09-22T10:39:12Z

@llvm/pr-subscribers-lldb

Author: nerix (Nerixyz)

Changes

If LLDB was built without the DIA SDK and the DIA reader is explicitly requested (through LLDB_USE_NATIVE_PDB_READER=0 or settings set plugin.symbol-file.pdb.reader dia), LLDB should print a warning, because it will use the native reader in any case (#159769 (comment)).

This PR adds the warning and a test when LLDB is not built with the SDK on Windows. I don't think any builder runs this configuration, as there are still five failing tests. I tested this locally with and without the SDK.

Full diff: https://github.com/llvm/llvm-project/pull/160067.diff

3 Files Affected:

(modified) lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp (+22-5)
(added) lldb/test/Shell/SymbolFile/NativePDB/native-setting.cpp (+65)
(modified) lldb/test/Shell/SymbolFile/PDB/native-setting.cpp (+19-6)

diff --git a/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp b/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp
index 0e2ca1784e7e9..68e229b697116 100644
--- a/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp
+++ b/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp
@@ -14,6 +14,7 @@
 #include "clang/Lex/Lexer.h"
 
 #include "Plugins/TypeSystem/Clang/TypeSystemClang.h"
+#include "lldb/Core/Debugger.h"
 #include "lldb/Core/Mangled.h"
 #include "lldb/Core/Module.h"
 #include "lldb/Core/PluginManager.h"
@@ -105,7 +106,6 @@ enum {
 #include "SymbolFilePDBPropertiesEnum.inc"
 };
 
-#if LLVM_ENABLE_DIA_SDK && defined(_WIN32)
 bool ShouldUseNativeReaderByDefault() {
   static bool g_use_native_by_default = true;
 
@@ -117,11 +117,16 @@ bool ShouldUseNativeReaderByDefault() {
         !env_value.equals_insensitive("1") &&
         !env_value.equals_insensitive("true"))
       g_use_native_by_default = false;
+
+#if !LLVM_ENABLE_DIA_SDK || !defined(_WIN32)
+    // if the environment value is unset, the native reader is requested
+    if (env_value.empty())
+      g_use_native_by_default = true;
+#endif
   });
 
   return g_use_native_by_default;
 }
-#endif
 
 class PluginProperties : public Properties {
 public:
@@ -136,6 +141,21 @@ class PluginProperties : public Properties {
 
   bool UseNativeReader() const {
 #if LLVM_ENABLE_DIA_SDK && defined(_WIN32)
+    return IsNativeReaderRequested();
+#else
+    if (!IsNativeReaderRequested()) {
+      static std::once_flag g_warning_shown;
+      Debugger::ReportWarning(
+          "The DIA PDB reader was explicitly requested, but LLDB was built "
+          "without the DIA SDK. The native reader will be used instead.",
+          {}, &g_warning_shown);
+    }
+    return true;
+#endif
+  }
+
+private:
+  bool IsNativeReaderRequested() const {
     auto value =
         GetPropertyAtIndexAs<PDBReader>(ePropertyReader, ePDBReaderDefault);
     switch (value) {
@@ -147,9 +167,6 @@ class PluginProperties : public Properties {
     case ePDBReaderDefault:
       return ShouldUseNativeReaderByDefault();
     }
-#else
-    return true;
-#endif
   }
 };
 
diff --git a/lldb/test/Shell/SymbolFile/NativePDB/native-setting.cpp b/lldb/test/Shell/SymbolFile/NativePDB/native-setting.cpp
new file mode 100644
index 0000000000000..fc0ee218dd0d2
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/NativePDB/native-setting.cpp
@@ -0,0 +1,65 @@
+// REQUIRES: !diasdk, target-windows
+
+// Test plugin.symbol-file.pdb.reader setting without the DIA SDK
+// RUN: %build -o %t.exe -- %s
+// RUN: env -u LLDB_USE_NATIVE_PDB_READER %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=NO-ENV %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER= %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=NO-ENV %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=0 %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=ENV0 %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=1 %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=ENV1 %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=0 %lldb \
+// RUN:     -o 'settings set plugin.symbol-file.pdb.reader dia' \
+// RUN:     -o 'target create %t.exe' \
+// RUN:     -o 'target modules dump symfile' \
+// RUN:     2>&1 | FileCheck --check-prefix=ENV0-SET-DIA %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=1 %lldb \
+// RUN:     -o 'settings set plugin.symbol-file.pdb.reader dia' \
+// RUN:     -o 'target create %t.exe' \
+// RUN:     -o 'target modules dump symfile' \
+// RUN:     2>&1 | FileCheck --check-prefix=ENV1-SET-DIA %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=0 %lldb \
+// RUN:     -o 'settings set plugin.symbol-file.pdb.reader native' \
+// RUN:     -o 'target create %t.exe' \
+// RUN:     -o 'target modules dump symfile' \
+// RUN:     2>&1 | FileCheck --check-prefix=ENV0-SET-NATIVE %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=1 %lldb \
+// RUN:     -o 'settings set plugin.symbol-file.pdb.reader native' \
+// RUN:     -o 'target create %t.exe' \
+// RUN:     -o 'target modules dump symfile' \
+// RUN:     2>&1 | FileCheck --check-prefix=ENV1-SET-NATIVE %s
+
+// NO-ENV-NOT: warning:
+// NO-ENV: (lldb) target modules dump symfile
+// NO-ENV: Dumping debug symbols for 1 modules.
+// NO-ENV: SymbolFile native-pdb
+
+// ENV0: warning: The DIA PDB reader was explicitly requested, but LLDB was built without the DIA SDK. The native reader will be used instead.
+// ENV0: (lldb) target modules dump symfile
+// ENV0: Dumping debug symbols for 1 modules.
+// ENV0: SymbolFile native-pdb
+
+// ENV1-NOT: warning:
+// ENV1: (lldb) target modules dump symfile
+// ENV1: Dumping debug symbols for 1 modules.
+// ENV1: SymbolFile native-pdb
+
+// ENV0-SET-DIA: warning: The DIA PDB reader was explicitly requested, but LLDB was built without the DIA SDK. The native reader will be used instead.
+// ENV0-SET-DIA: (lldb) target modules dump symfile
+// ENV0-SET-DIA: Dumping debug symbols for 1 modules.
+// ENV0-SET-DIA: SymbolFile native-pdb
+
+// ENV1-SET-DIA: warning: The DIA PDB reader was explicitly requested, but LLDB was built without the DIA SDK. The native reader will be used instead.
+// ENV1-SET-DIA: (lldb) target modules dump symfile
+// ENV1-SET-DIA: Dumping debug symbols for 1 modules.
+// ENV1-SET-DIA: SymbolFile native-pdb
+
+// ENV1-SET-NATIVE-NOT: warning:
+// ENV0-SET-NATIVE: (lldb) target modules dump symfile
+// ENV0-SET-NATIVE: Dumping debug symbols for 1 modules.
+// ENV0-SET-NATIVE: SymbolFile native-pdb
+
+// ENV1-SET-NATIVE-NOT: warning:
+// ENV1-SET-NATIVE: (lldb) target modules dump symfile
+// ENV1-SET-NATIVE: Dumping debug symbols for 1 modules.
+// ENV1-SET-NATIVE: SymbolFile native-pdb
+
+int main() {}
diff --git a/lldb/test/Shell/SymbolFile/PDB/native-setting.cpp b/lldb/test/Shell/SymbolFile/PDB/native-setting.cpp
index a3077252f08f1..750a61666912d 100644
--- a/lldb/test/Shell/SymbolFile/PDB/native-setting.cpp
+++ b/lldb/test/Shell/SymbolFile/PDB/native-setting.cpp
@@ -2,49 +2,62 @@
 
 // Test plugin.symbol-file.pdb.reader setting
 // RUN: %build -o %t.exe -- %s
-// RUN: env LLDB_USE_NATIVE_PDB_READER=0 %lldb %t.exe -o 'target modules dump symfile' | FileCheck --check-prefix=ENV0 %s
-// RUN: env LLDB_USE_NATIVE_PDB_READER=1 %lldb %t.exe -o 'target modules dump symfile' | FileCheck --check-prefix=ENV1 %s
+// RUN: env -u LLDB_USE_NATIVE_PDB_READER %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=NO-ENV %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER= %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=NO-ENV %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=0 %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=ENV0 %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=1 %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=ENV1 %s
 // RUN: env LLDB_USE_NATIVE_PDB_READER=0 %lldb \
 // RUN:     -o 'settings set plugin.symbol-file.pdb.reader dia' \
 // RUN:     -o 'target create %t.exe' \
 // RUN:     -o 'target modules dump symfile' \
-// RUN:     | FileCheck --check-prefix=ENV0-SET-DIA %s
+// RUN:     2>&1 | FileCheck --check-prefix=ENV0-SET-DIA %s
 // RUN: env LLDB_USE_NATIVE_PDB_READER=1 %lldb \
 // RUN:     -o 'settings set plugin.symbol-file.pdb.reader dia' \
 // RUN:     -o 'target create %t.exe' \
 // RUN:     -o 'target modules dump symfile' \
-// RUN:     | FileCheck --check-prefix=ENV1-SET-DIA %s
+// RUN:     2>&1 | FileCheck --check-prefix=ENV1-SET-DIA %s
 // RUN: env LLDB_USE_NATIVE_PDB_READER=0 %lldb \
 // RUN:     -o 'settings set plugin.symbol-file.pdb.reader native' \
 // RUN:     -o 'target create %t.exe' \
 // RUN:     -o 'target modules dump symfile' \
-// RUN:     | FileCheck --check-prefix=ENV0-SET-NATIVE %s
+// RUN:     2>&1 | FileCheck --check-prefix=ENV0-SET-NATIVE %s
 // RUN: env LLDB_USE_NATIVE_PDB_READER=1 %lldb \
 // RUN:     -o 'settings set plugin.symbol-file.pdb.reader native' \
 // RUN:     -o 'target create %t.exe' \
 // RUN:     -o 'target modules dump symfile' \
-// RUN:     | FileCheck --check-prefix=ENV1-SET-NATIVE %s
+// RUN:     2>&1 | FileCheck --check-prefix=ENV1-SET-NATIVE %s
 
+// NO-ENV-NOT: warning:
+// NO-ENV: (lldb) target modules dump symfile
+// NO-ENV: Dumping debug symbols for 1 modules.
+// NO-ENV: SymbolFile pdb
+
+// ENV0-NOT: warning:
 // ENV0: (lldb) target modules dump symfile
 // ENV0: Dumping debug symbols for 1 modules.
 // ENV0: SymbolFile pdb
 
+// ENV1-NOT: warning:
 // ENV1: (lldb) target modules dump symfile
 // ENV1: Dumping debug symbols for 1 modules.
 // ENV1: SymbolFile native-pdb
 
+// ENV0-SET-DIA-NOT: warning:
 // ENV0-SET-DIA: (lldb) target modules dump symfile
 // ENV0-SET-DIA: Dumping debug symbols for 1 modules.
 // ENV0-SET-DIA: SymbolFile pdb
 
+// ENV1-SET-DIA-NOT: warning:
 // ENV1-SET-DIA: (lldb) target modules dump symfile
 // ENV1-SET-DIA: Dumping debug symbols for 1 modules.
 // ENV1-SET-DIA: SymbolFile pdb
 
+// ENV0-SET-NATIVE-NOT: warning:
 // ENV0-SET-NATIVE: (lldb) target modules dump symfile
 // ENV0-SET-NATIVE: Dumping debug symbols for 1 modules.
 // ENV0-SET-NATIVE: SymbolFile native-pdb
 
+// ENV1-SET-NATIVE-NOT: warning:
 // ENV1-SET-NATIVE: (lldb) target modules dump symfile
 // ENV1-SET-NATIVE: Dumping debug symbols for 1 modules.
 // ENV1-SET-NATIVE: SymbolFile native-pdb

If `case ePDBReaderDefault` and `default` is used, Clang and GCC complain. If only `case ePDBReaderDefault` is used, MSVC complains.

lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp

lldb/test/Shell/SymbolFile/NativePDB/native-setting.cpp

lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp

Co-authored-by: Michael Buch <[email protected]>

JDevlieghere · 2025-09-23T20:36:14Z

lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp

+          "The DIA PDB reader was explicitly requested, but LLDB was built "
+          "without the DIA SDK. The native reader will be used instead.",
+          {}, &g_warning_shown);


Errors and warnings should start the first sentence with a lowercase letter, and finish the last sentence without a period, if it would end in one otherwise.

Suggested change

"The DIA PDB reader was explicitly requested, but LLDB was built "

"without the DIA SDK. The native reader will be used instead.",

{}, &g_warning_shown);

"the DIA PDB reader was explicitly requested, but LLDB was built "

"without the DIA SDK. The native reader will be used instead",

{}, &g_warning_shown);

Sorry, I forgot that. Opened #160398.

No worries, thanks for the quick fix!

Makes the warning message conform to the [LLVM error and warning style](https://llvm.org/docs/CodingStandards.html#error-and-warning-messages) as mentioned in #160067 (comment).

Makes the warning message conform to the [LLVM error and warning style](https://llvm.org/docs/CodingStandards.html#error-and-warning-messages) as mentioned in llvm/llvm-project#160067 (comment).

[LLDB][PDB] Warn if DIA plugin is requested but not available

4dab54f

Nerixyz requested a review from JDevlieghere as a code owner September 22, 2025 10:38

llvmbot added the lldb label Sep 22, 2025

fix: use default in switch

c4927f3

If `case ePDBReaderDefault` and `default` is used, Clang and GCC complain. If only `case ePDBReaderDefault` is used, MSVC complains.

Michael137 reviewed Sep 22, 2025

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lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp Show resolved Hide resolved

Michael137 reviewed Sep 22, 2025

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lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp Show resolved Hide resolved

Michael137 reviewed Sep 22, 2025

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lldb/test/Shell/SymbolFile/NativePDB/native-setting.cpp Show resolved Hide resolved

Nerixyz added 2 commits September 22, 2025 19:29

fix: use lambda for static

482623b

test: add checks for non-booleanish values

3933e2d

Michael137 approved these changes Sep 23, 2025

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lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp Outdated Show resolved Hide resolved

fix: add const

45a3ace

Co-authored-by: Michael Buch <[email protected]>

Nerixyz merged commit 5b3dd43 into llvm:main Sep 23, 2025
9 checks passed

JDevlieghere reviewed Sep 23, 2025

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Nerixyz mentioned this pull request Sep 23, 2025

[LLDB][PDB] Fix plugin warning message style #160398

Merged

Nerixyz deleted the chore/lldb-pdb-warn-on-dia branch November 7, 2025 14:16

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[LLDB][PDB] Warn if DIA plugin is requested but not available #160067

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