[lld] [llvm] [DTLTO][LLD][ELF] Support bitcode members of thin archives (PR #149425)

[Fangrui Song via llvm-commits]

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@@ -1753,6 +1754,39 @@ static uint8_t getOsAbi(const Triple &t) {
   }
 }
 
+// For DTLTO, bitcode member names must be valid paths to files on disk.
+// For thin archives, resolve `memberPath` relative to the archive's location.
+// Returns true if adjusted; false otherwise. Non-thin archives are unsupported.
+static bool dtltoAdjustMemberPathIfThinArchive(Ctx &ctx, StringRef archivePath,
+                                               std::string &memberPath) {
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MaskRay wrote:

The parameter type can use `SmallString<128>` to remove a SmallString->string conversion.

https://github.com/llvm/llvm-project/pull/149425