Auto merge of #121297 - michaelwoerister:set-pdb-alt-path, r=wesleywiser

link.exe: Don't embed full path to PDB file in binary.

This PR makes `rustc` unconditionally pass `/PDBALTPATH:%_PDB%` to MSVC-style linkers, causing the linker to only embed the filename of the PDB in the binary instead of the full path. This will help implement the [trim-paths RFC](https://github.com/rust-lang/rust/issues/111540) for `*-msvc` targets.

Passing `/PDBALTPATH:%_PDB%` to the linker is already done by many projects that need reproducible builds and [debugger's should still be able to find the PDB](https://learn.microsoft.com/cpp/build/reference/pdbpath) if it is in the same directory as the binary.

r? `@ghost`

Fixes https://github.com/rust-lang/rust/issues/87825

1 files changed, 9 insertions, 0 deletions

diff --git a/compiler/rustc_codegen_ssa/src/back/linker.rs b/compiler/rustc_codegen_ssa/src/back/linker.rs
index bb23e21b2a2..f5640ea26bc 100644
--- a/compiler/rustc_codegen_ssa/src/back/linker.rs
+++ b/compiler/rustc_codegen_ssa/src/back/linker.rs
@@ -929,6 +929,15 @@ impl<'a> Linker for MsvcLinker<'a> {
                 // from the CodeView line tables in the object files.
                 self.cmd.arg("/DEBUG");
 
+                // Default to emitting only the file name of the PDB file into
+                // the binary instead of the full path. Emitting the full path
+                // may leak private information (such as user names).
+                // See https://github.com/rust-lang/rust/issues/87825.
+                //
+                // This default behavior can be overridden by explicitly passing
+                // `-Clink-arg=/PDBALTPATH:...` to rustc.
+                self.cmd.arg("/PDBALTPATH:%_PDB%");
+
                 // This will cause the Microsoft linker to embed .natvis info into the PDB file
                 let natvis_dir_path = self.sess.sysroot.join("lib\\rustlib\\etc");
                 if let Ok(natvis_dir) = fs::read_dir(&natvis_dir_path) {