Set per-target compile PDB for cDAC descriptor object libraries

[lewing]

Note

This PR was authored with assistance from GitHub Copilot.

Problem

The OBJECT libraries created by generate_data_descriptors() in src/coreclr/clrdatadescriptors.cmake compile contract-descriptor.c and contractpointerdata.cpp with MSVC defaults, which routes debug info into the compiler-default vc140.pdb. That PDB does not travel with the .obj files when they are archived into a static library such as Runtime.ServerGC.lib.

Downstream linkers — in particular the NativeAOT publish of ILCompiler, crossgen2, and ilasm on Windows — then emit LNK4099 ("PDB 'vc140.pdb' was not found") for each affected object, which is fatal under /WX.

Symptom

The dotnet/runtime → dotnet/dotnet codeflow PR dotnet/dotnet#6423 is blocked: the VMR Vertical Build Windows_x64 and VMR Vertical Build Windows_x86 legs both fail with 22 LNK4099 errors apiece, e.g.:

Runtime.ServerGC.lib(contract-descriptor.c.obj) : error LNK4099:
  PDB 'vc140.pdb' was not found with 'Runtime.ServerGC.lib(contract-descriptor.c.obj)'
  or at '...\artifacts\bin\ILCompiler_publish\x64\Release\native\vc140.pdb';
  linking object as if no debug info
   [src\coreclr\tools\aot\ILCompiler\ILCompiler_publish.csproj]
Runtime.ServerGC.lib(contractpointerdata.cpp.obj) : error LNK4099: ...

repeated for crossgen2_publish.csproj and ilasm.csproj. Linux/macOS/WASM/iOS/Android verticals all pass — LNK4099 is MSVC-specific.

The regression was introduced by #126972 ("[NativeAOT] Add cDAC data descriptor infrastructure"), which wired the new descriptor OBJECT libraries into the NativeAOT runtime so they end up archived inside Runtime.ServerGC.lib.

Fix

Set COMPILE_PDB_NAME and COMPILE_PDB_OUTPUT_DIRECTORY on ${LIBRARY} so each descriptor library produces its own deterministic PDB that the consuming linker can locate. This matches the convention already used by install_static_library in eng/native/functions.cmake.

Validation

• CMake reconfigures cleanly.
• Ninja built nativeaot_gc_svr_descriptor, nativeaot_gc_wks_descriptor, nativeaot_cdac_contract_descriptor, and cdac_contract_descriptor without errors on linux-x64.
• The actual LNK4099 resolution can only be verified on a Windows NativeAOT publish leg in CI; please pay particular attention to the Windows legs and to the next forward-flow into dotnet/dotnet.

cc @max-charlamb (author of #126972)

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[Copilot]

Pull request overview

This PR updates CoreCLR’s cDAC descriptor OBJECT libraries so that, when built with MSVC, they emit per-target compile PDBs instead of falling back to the default vc140.pdb name. This is intended to prevent downstream Windows NativeAOT publish link failures caused by LNK4099 when those object files are later archived into static libraries (e.g., Runtime.ServerGC.lib) and linked under /WX.

Changes:

• Add MSVC-only set_target_properties to set COMPILE_PDB_NAME and COMPILE_PDB_OUTPUT_DIRECTORY for descriptor object library targets created by generate_data_descriptors().

[max-charlamb]

Thanks for the fix. This change looks reasonable if it fixes the VMR. It shouldn't have an impact on the actual data descriptor.

[steveisok]

#127773 introduced a GCC 15 -Werror sign-compare regression. Pushed a commit to fix that along with the original change.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.