[LLDB] Use native PDB reader by default #165363

Nerixyz · 2025-10-28T09:56:43Z

All PDB tests now pass when compiled without DIA on Windows, so they pass with the native reader.

With this PR, the default reader changes to the native reader.
The plan is to eventually remove the DIA reader (see https://discourse.llvm.org/t/rfc-removing-the-dia-pdb-plugin-from-lldb/87827 and #114906).

For now, DIA can be used by setting plugin.symbol-file.pdb.reader to dia or by setting LLDB_USE_NATIVE_PDB_READER=0 (mostly undocumented, but used in tests).

llvmbot · 2025-10-28T09:57:21Z

@llvm/pr-subscribers-lldb

Author: nerix (Nerixyz)

Changes

All PDB tests now pass when compiled without DIA on Windows, so they pass with the native reader.

With this PR, the default reader changes to the native reader.
The plan is to eventually remove the DIA reader (see https://discourse.llvm.org/t/rfc-removing-the-dia-pdb-plugin-from-lldb/87827 and #114906).

For now, DIA can be used by setting plugin.symbol-file.pdb.reader to dia or by setting LLDB_USE_NATIVE_PDB_READER=0 (mostly undocumented, but used in tests).

Full diff: https://github.com/llvm/llvm-project/pull/165363.diff

4 Files Affected:

(modified) lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp (+6-12)
(modified) lldb/test/Shell/SymbolFile/NativePDB/native-setting.cpp (+3-3)
(modified) lldb/test/Shell/SymbolFile/PDB/native-setting.cpp (+4-4)
(modified) llvm/docs/ReleaseNotes.md (+4)

diff --git a/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp b/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp
index 3b936c06b1072..0ccb1804bb13a 100644
--- a/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp
+++ b/lldb/source/Plugins/SymbolFile/PDB/SymbolFilePDB.cpp
@@ -83,8 +83,8 @@ constexpr OptionEnumValueElement g_pdb_reader_enums[] = {
     {
         ePDBReaderDefault,
         "default",
-        "Use DIA PDB reader unless LLDB_USE_NATIVE_PDB_READER environment "
-        "variable is set",
+        "Use native PDB reader unless LLDB_USE_NATIVE_PDB_READER environment "
+        "is set to 0",
     },
     {
         ePDBReaderDIA,
@@ -109,16 +109,10 @@ enum {
 static const bool g_should_use_native_reader_by_default = [] {
   llvm::StringRef env_value = ::getenv("LLDB_USE_NATIVE_PDB_READER");
 
-#if !LLVM_ENABLE_DIA_SDK || !defined(_WIN32)
-  // if the environment value is unset, the native reader is requested
-  if (env_value.empty())
-    return true;
-#endif
-
-  return env_value.equals_insensitive("on") ||
-         env_value.equals_insensitive("yes") ||
-         env_value.equals_insensitive("1") ||
-         env_value.equals_insensitive("true");
+  return !env_value.equals_insensitive("off") &&
+         !env_value.equals_insensitive("no") &&
+         !env_value.equals_insensitive("0") &&
+         !env_value.equals_insensitive("false");
 }();
 
 class PluginProperties : public Properties {
diff --git a/lldb/test/Shell/SymbolFile/NativePDB/native-setting.cpp b/lldb/test/Shell/SymbolFile/NativePDB/native-setting.cpp
index dc26ec8d30cb4..91f451fd0dadc 100644
--- a/lldb/test/Shell/SymbolFile/NativePDB/native-setting.cpp
+++ b/lldb/test/Shell/SymbolFile/NativePDB/native-setting.cpp
@@ -8,9 +8,9 @@
 // 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=foo %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=ENV0 %s
-// RUN: env LLDB_USE_NATIVE_PDB_READER=42 %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=ENV0 %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=foo %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=ENV1 %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=42 %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=ENV1 %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' \
diff --git a/lldb/test/Shell/SymbolFile/PDB/native-setting.cpp b/lldb/test/Shell/SymbolFile/PDB/native-setting.cpp
index f5e54592b0b31..54b7f28a71259 100644
--- a/lldb/test/Shell/SymbolFile/PDB/native-setting.cpp
+++ b/lldb/test/Shell/SymbolFile/PDB/native-setting.cpp
@@ -8,9 +8,9 @@
 // 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=foo %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=ENV0 %s
-// RUN: env LLDB_USE_NATIVE_PDB_READER=42 %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=ENV0 %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=foo %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=ENV1 %s
+// RUN: env LLDB_USE_NATIVE_PDB_READER=42 %lldb %t.exe -o 'target modules dump symfile' 2>&1 | FileCheck --check-prefix=ENV1 %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' \
@@ -36,7 +36,7 @@
 // NO-ENV-NOT: warning:
 // NO-ENV: (lldb) target modules dump symfile
 // NO-ENV: Dumping debug symbols for 1 modules.
-// NO-ENV: SymbolFile pdb
+// NO-ENV: SymbolFile native-pdb
 
 // ENV0-NOT: warning:
 // ENV0: (lldb) target modules dump symfile
diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index 36383b12788f9..fa99fc0338c56 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -191,6 +191,10 @@ Changes to LLDB
 * The `show-progress` setting, which became a NOOP with the introduction of the
   statusline, now defaults to off and controls using OSC escape codes to show a
   native progress bar in supporting terminals like Ghostty and ConEmu.
+* The default PDB reader on Windows was changed from DIA to native, which uses 
+  LLVM's PDB and CodeView support. You can switch back to the DIA reader with
+  `settings set plugin.symbol-file.pdb.reader dia`. Note that support for the
+  DIA reader will be removed in future versions of LLDB.
 
 Changes to BOLT
 ---------------------------------

llvm/docs/ReleaseNotes.md

Michael137

SGTM, thanks for pushing through! Excited to see one of these plugins go away.

I assume the PDB shell-tests all explicitly turn on DIA? And the native ones turn it off? I.e., all the test coverage remains the same after this patch?

Please let @DavidSpickett and @JDevlieghere also take a look before merging.

DavidSpickett

LGTM with a small comment on the release note.

I might have expected to see a lot of tests flip from opting in to opting out, but I think thanks to yours and others' hard work, all the tests run on both plugins now, correct?

llvm/docs/ReleaseNotes.md

DavidSpickett · 2025-10-28T14:19:09Z

I also forgot that when not built on Windows, we have always been using native. So this work has improved the remote debugging experience too!

omjavaid · 2025-10-28T15:57:07Z

Thanks for this.

Nerixyz · 2025-10-28T16:55:44Z

I assume the PDB shell-tests all explicitly turn on DIA? And the native ones turn it off? I.e., all the test coverage remains the same after this patch?

Yes, they use the environment variable:

llvm-project/lldb/test/Shell/SymbolFile/PDB/lit.local.cfg

Line 1 in e5668d3

config.environment["LLDB_USE_NATIVE_PDB_READER"] = "0"

llvm-project/lldb/test/Shell/SymbolFile/NativePDB/lit.local.cfg

Line 1 in e5668d3

config.environment["LLDB_USE_NATIVE_PDB_READER"] = "1"

JDevlieghere

This is a huge achievement. Congratulations and thank you to everyone that helped make this happen.

charles-zablit

Thank you for this!

DavidSpickett · 2025-10-29T09:37:30Z

The setting is not in any release yet. Before, you had to use the environment variable.

I did not realise the setting hasn't been around that long. It was added in #151490:

This would make it possible to test both native PDB and DIA PDB in the API tests (see linked PR).

So for as long as we do / might need to do this, the setting remains. Even if we don't mention it in release notes, it is something users can discover. I was wondering if we should remove it so we didn't have one more thing to keep around for another release cycle.

I think not though. If all goes to plan:

Native becomes the default in the next release.
DIA is removed the release after, and the setting only accepts native.
Release after that, if we remember, we can remove the setting. If we forget it's not a big deal, since it's basically read only at that point.

You can merge this whenever you're ready.

Nerixyz · 2025-10-29T15:51:34Z

Thank you to everyone who helped with the native plugin and LLVM's PDB support!

llvm-ci · 2025-10-29T16:36:26Z

LLVM Buildbot has detected a new failure on builder lldb-x86_64-win running on as-builder-10 while building lldb,llvm at step 8 "test-check-lldb-unit".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/211/builds/3312

Here is the relevant piece of the build log for the reference

Step 8 (test-check-lldb-unit) failure: Test just built components: check-lldb-unit completed (failure)
******************** TEST 'lldb-unit :: SymbolFile/PDB/./SymbolFilePDBTests.exe/14/18' FAILED ********************
Script(shard):
--
GTEST_OUTPUT=json:C:\buildbot\as-builder-10\lldb-x86-64\build\tools\lldb\unittests\SymbolFile\PDB\.\SymbolFilePDBTests.exe-lldb-unit-44948-14-18.json GTEST_SHUFFLE=0 GTEST_TOTAL_SHARDS=18 GTEST_SHARD_INDEX=14 C:\buildbot\as-builder-10\lldb-x86-64\build\tools\lldb\unittests\SymbolFile\PDB\.\SymbolFilePDBTests.exe
--

Script:
--
C:\buildbot\as-builder-10\lldb-x86-64\build\tools\lldb\unittests\SymbolFile\PDB\.\SymbolFilePDBTests.exe --gtest_filter=SymbolFilePDBTests.TestRegexNameMatch
--
unknown file: error: SEH exception with code 0x3221225477 thrown in the test body.
Stack trace:



unknown file
SEH exception with code 0x3221225477 thrown in the test body.
Stack trace:




********************

Step 9 (test-check-lldb-api) failure: Test just built components: check-lldb-api completed (failure)
...
PASS: lldb-api :: functionalities/module_cache/universal/TestModuleCacheUniversal.py (539 of 1318)
PASS: lldb-api :: functionalities/memory/tag/TestMemoryTag.py (540 of 1318)
PASS: lldb-api :: functionalities/multiword-commands/TestMultiWordCommands.py (541 of 1318)
PASS: lldb-api :: functionalities/memory/find/TestMemoryFind.py (542 of 1318)
PASS: lldb-api :: functionalities/gdb_remote_client/TestPlatformKill.py (543 of 1318)
PASS: lldb-api :: functionalities/object-file/TestImageListMultiArchitecture.py (544 of 1318)
PASS: lldb-api :: functionalities/inferior-crashing/recursive-inferior/TestRecursiveInferiorStep.py (545 of 1318)
UNSUPPORTED: lldb-api :: functionalities/param_entry_vals/basic_entry_values/TestBasicEntryValues.py (546 of 1318)
PASS: lldb-api :: functionalities/paths/TestPaths.py (547 of 1318)
UNRESOLVED: lldb-api :: functionalities/multiple-slides/TestMultipleSlides.py (548 of 1318)
******************** TEST 'lldb-api :: functionalities/multiple-slides/TestMultipleSlides.py' FAILED ********************
Script:
--
C:/Python312/python.exe C:/buildbot/as-builder-10/lldb-x86-64/llvm-project/lldb\test\API\dotest.py -u CXXFLAGS -u CFLAGS --env LLVM_LIBS_DIR=C:/buildbot/as-builder-10/lldb-x86-64/build/./lib --env LLVM_INCLUDE_DIR=C:/buildbot/as-builder-10/lldb-x86-64/build/include --env LLVM_TOOLS_DIR=C:/buildbot/as-builder-10/lldb-x86-64/build/./bin --arch x86_64 --build-dir C:/buildbot/as-builder-10/lldb-x86-64/build/lldb-test-build.noindex --lldb-module-cache-dir C:/buildbot/as-builder-10/lldb-x86-64/build/lldb-test-build.noindex/module-cache-lldb\lldb-api --clang-module-cache-dir C:/buildbot/as-builder-10/lldb-x86-64/build/lldb-test-build.noindex/module-cache-clang\lldb-api --executable C:/buildbot/as-builder-10/lldb-x86-64/build/./bin/lldb.exe --compiler C:/buildbot/as-builder-10/lldb-x86-64/build/./bin/clang.exe --dsymutil C:/buildbot/as-builder-10/lldb-x86-64/build/./bin/dsymutil.exe --make C:/ninja/make.exe --llvm-tools-dir C:/buildbot/as-builder-10/lldb-x86-64/build/./bin --lldb-obj-root C:/buildbot/as-builder-10/lldb-x86-64/build/tools/lldb --lldb-libs-dir C:/buildbot/as-builder-10/lldb-x86-64/build/./lib --cmake-build-type Release --skip-category=lldb-dap C:\buildbot\as-builder-10\lldb-x86-64\llvm-project\lldb\test\API\functionalities\multiple-slides -p TestMultipleSlides.py
--
Exit Code: 1

Command Output (stdout):
--
lldb version 22.0.0git (https://github.com/llvm/llvm-project.git revision 287ca7b243facc7185bbd9dfdaa5a6a012819e1b)
  clang revision 287ca7b243facc7185bbd9dfdaa5a6a012819e1b
  llvm revision 287ca7b243facc7185bbd9dfdaa5a6a012819e1b
Skipping the following test categories: ['lldb-dap', 'libc++', 'libstdcxx', 'dwo', 'dsym', 'gmodules', 'debugserver', 'objc', 'fork', 'pexpect']


--
Command Output (stderr):
--
FAIL: LLDB (C:\buildbot\as-builder-10\lldb-x86-64\build\bin\clang.exe-x86_64) :: test_mulitple_slides (TestMultipleSlides.MultipleSlidesTestCase.test_mulitple_slides)

======================================================================

ERROR: test_mulitple_slides (TestMultipleSlides.MultipleSlidesTestCase.test_mulitple_slides)

   Test that a binary can be slid multiple times correctly.

----------------------------------------------------------------------

Traceback (most recent call last):

  File "C:\buildbot\as-builder-10\lldb-x86-64\llvm-project\lldb\test\API\functionalities\multiple-slides\TestMultipleSlides.py", line 78, in test_mulitple_slides

    error = target.SetModuleLoadAddress(module, first_size - 64)

            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

  File "C:\buildbot\as-builder-10\lldb-x86-64\build\Lib\site-packages\lldb\__init__.py", line 13519, in SetModuleLoadAddress

    return _lldb.SBTarget_SetModuleLoadAddress(self, module, sections_offset)

Fixes the failing DIA unit test (https://lab.llvm.org/buildbot/#/builders/197/builds/10342) after #165363. Now that the native plugin is the default, we need to set the symbol file plugin for DIA via the settings.

After the default PDB plugin changed to the native one (#165363), this test failed, because it uses the size of public symbols and the native plugin sets the size to 0 (as PDB doesn't include this information explicitly). A PDB was built because the final executable in that test was linked with `-gdwarf`.

slydiman · 2025-10-29T19:43:35Z

LLVM Buildbot has detected a new failure on builder lldb-x86_64-win running on as-builder-10 while building lldb,llvm at step 8 "test-check-lldb-unit".

The buildbots lldb-remote-linux-win and lldb-aarch64-windows are broken too.

So, all lldb Windows buildbots are broken. I recommend to revert this patch for now and investigate the problem.

Nerixyz · 2025-10-29T19:48:07Z

The buildbots lldb-remote-linux-win and lldb-aarch64-windows are broken too.

They're no longer broken after the two PRs.

slydiman · 2025-10-29T19:57:55Z

Ok, thanks.

All PDB tests now pass when compiled without DIA on Windows, so they pass with the native reader. With this PR, the default reader changes to the native reader. The plan is to eventually remove the DIA reader (see https://discourse.llvm.org/t/rfc-removing-the-dia-pdb-plugin-from-lldb/87827 and llvm#114906). For now, DIA can be used by setting `plugin.symbol-file.pdb.reader` to `dia` or by setting `LLDB_USE_NATIVE_PDB_READER=0` (mostly undocumented, but used in tests).

Fixes the failing DIA unit test (https://lab.llvm.org/buildbot/#/builders/197/builds/10342) after llvm#165363. Now that the native plugin is the default, we need to set the symbol file plugin for DIA via the settings.

After the default PDB plugin changed to the native one (llvm#165363), this test failed, because it uses the size of public symbols and the native plugin sets the size to 0 (as PDB doesn't include this information explicitly). A PDB was built because the final executable in that test was linked with `-gdwarf`.

[LLDB] Use native PDB reader by default

cc5fdcb

Nerixyz requested review from DavidSpickett and Michael137 October 28, 2025 09:56

Nerixyz requested a review from JDevlieghere as a code owner October 28, 2025 09:56

llvmbot added the lldb label Oct 28, 2025

Michael137 reviewed Oct 28, 2025

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medismailben requested review from azabazno and charles-zablit and removed request for azabazno October 28, 2025 16:29

fix: use "in a future version"

34fa060

JDevlieghere approved these changes Oct 28, 2025

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charles-zablit approved these changes Oct 28, 2025

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Nerixyz merged commit 287ca7b into llvm:main Oct 29, 2025
10 of 11 checks passed

Nerixyz mentioned this pull request Oct 29, 2025

[LLDB][PDB] Explicitly set DIA plugin in unit test #165592

Merged

Nerixyz mentioned this pull request Oct 29, 2025

[LLDB] Skip TestMultipleSlides.py on Windows #165604

Merged

[LLDB] Use native PDB reader by default #165363

[LLDB] Use native PDB reader by default #165363

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