Support embedded portable PDBs for managed symbol resolution#2434
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JeremyKuhne wants to merge 3 commits into
Open
Support embedded portable PDBs for managed symbol resolution#2434JeremyKuhne wants to merge 3 commits into
JeremyKuhne wants to merge 3 commits into
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Managed assemblies built with <DebugType>embedded</DebugType> carry their portable PDB inside the PE image rather than in a standalone .pdb file. Previously SymbolReader could not read these, so source/line lookup failed for such modules. Add the ability to open an embedded portable PDB: - SymbolReader.OpenEmbeddedPortablePdb reads the EmbeddedPortablePdb debug-directory entry from a module and returns a PortableSymbolModule. Results are cached under a key suffixed so they cannot collide with standalone-PDB cache entries. - SymbolReader.OpenSymbolFileForModuleFile is a module-oriented entry point that prefers a standalone PDB and falls back to an embedded portable PDB. - PortableSymbolModule gains a constructor that takes a MetadataReaderProvider (which owns its own backing memory). - TraceLog.OpenPdbForModuleFile falls back to the module's embedded portable PDB when the on-disk module matches the trace and no standalone PDB exists. Tests: add an EmbeddedPdbTestApp fixture (built with embedded PDBs) and cover the happy path, caching, not-embedded/missing-file cases, the module-oriented entry point (embedded and standalone), and the end-to-end TraceLog fallback path. All run cross-platform on net462 and net8.0.
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Also tried the nupkg in a project where I need this support and it worked fine. |
In Release the C# compiler optimizes EmbeddedTarget.Add, shifting its first sequence point from the 'int sum = a + b;' line to the 'return' line, so the source-line assertions failed in the Release CI leg. Pin Optimize=false on the fixture so its emitted sequence points are stable regardless of the build configuration.
brianrob
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Jun 3, 2026
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I appreciate you putting this together. A couple of comments below.
| if (TraceModuleUnchanged(moduleFile, symReader.m_log)) | ||
| { | ||
| pdbFileName = symReader.FindSymbolFilePathForModule(moduleFile.FilePath); | ||
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This will work for traces that are captured on the same machine before the binaries are removed or overwritten. Should we be looking to capture the PDBs during trace merge so that anyone who captures a trace where binaries have embedded PDBs will have them extracted and zipped up with the etl (ala NGEN PDBs from .NET Framework)?
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Yeah, I think so. I can do a follow up that explores that if you'd like. :)
Per PR review: this wrapper was called only from tests, and TraceLog.OpenPdbForModuleFile already provides the standalone-then-embedded fallback for the trace path. Removed it and its three dedicated tests, keeping OpenEmbeddedPortablePdb (the building block TraceLog uses).
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Summary
Managed assemblies built with
<DebugType>embedded</DebugType>carry their portable PDB inside the PE image rather than in a standalone.pdbfile. PreviouslySymbolReadercould not read these, so source/line lookup failed for such modules. This PR adds the ability to read embedded portable PDBs.Changes
SymbolReader.OpenEmbeddedPortablePdb— reads theEmbeddedPortablePdbdebug-directory entry from a module and returns aPortableSymbolModule. Results are cached under a key suffixed so they cannot collide with standalone-PDB cache entries.PortableSymbolModule— gains a constructor that takes aMetadataReaderProvider(which owns its own backing memory, so the module survives disposal of thePEReader/FileStreamused to open it).TraceLog.OpenPdbForModuleFile— falls back to the module's embedded portable PDB when the on-disk module matches the trace and no standalone PDB exists.Tests
Adds an
EmbeddedPdbTestAppfixture (built with<DebugType>embedded</DebugType>) and covers:PEReaderis disposed,TraceLogfallback path.All tests run cross-platform on net462 and net8.0 in Debug.