Rollup merge of #93269 - jacobbramley:dev/pauth-option-1, r=petrochenkov

Use error-on-mismatch policy for PAuth module flags.

This agrees with Clang, and avoids an error when using LTO with mixed
C/Rust. LLVM considers different behaviour flags to be a mismatch,
even when the flag value itself is the same.

This also makes the flag setting explicit for all uses of
LLVMRustAddModuleFlag.

----

I believe that this fixes #92885, but have only reproduced it locally on Linux hosts so cannot confirm that it fixes the issue as reported.

I have not included a test for this because it is covered by an existing test (`src/test/run-make-fulldeps/cross-lang-lto-clang`). It is not without its problems, though:
* The test requires Clang and `--run-clang-based-tests-with=...` to run, and this is not the case on the CI.
   * Any test I add would have a similar requirement.
* With this patch applied, the test gets further, but it still fails (for other reasons). I don't think that affects #92885.

1 files changed, 13 insertions, 2 deletions

diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
index 61e49fab6ff..28eb8e2a0a4 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/mod.rs
@@ -108,18 +108,29 @@ impl<'a, 'tcx> CrateDebugContext<'a, 'tcx> {
             // This can be overridden using --llvm-opts -dwarf-version,N.
             // Android has the same issue (#22398)
             if let Some(version) = sess.target.dwarf_version {
-                llvm::LLVMRustAddModuleFlag(self.llmod, "Dwarf Version\0".as_ptr().cast(), version)
+                llvm::LLVMRustAddModuleFlag(
+                    self.llmod,
+                    llvm::LLVMModFlagBehavior::Warning,
+                    "Dwarf Version\0".as_ptr().cast(),
+                    version,
+                )
             }
 
             // Indicate that we want CodeView debug information on MSVC
             if sess.target.is_like_msvc {
-                llvm::LLVMRustAddModuleFlag(self.llmod, "CodeView\0".as_ptr().cast(), 1)
+                llvm::LLVMRustAddModuleFlag(
+                    self.llmod,
+                    llvm::LLVMModFlagBehavior::Warning,
+                    "CodeView\0".as_ptr().cast(),
+                    1,
+                )
             }
 
             // Prevent bitcode readers from deleting the debug info.
             let ptr = "Debug Info Version\0".as_ptr();
             llvm::LLVMRustAddModuleFlag(
                 self.llmod,
+                llvm::LLVMModFlagBehavior::Warning,
                 ptr.cast(),
                 llvm::LLVMRustDebugMetadataVersion(),
             );