Rollup merge of rust-lang#105298 - krasimirgg:llvm-16-dec-1, r=cuviper

llvm-wrapper: adapt for an LLVM API change

Adapts llvm-wrapper for llvm/llvm-project@8c7c20f.
No functional changes intended.

Found via our experimental rust + llvm @ HEAD bot: https://buildkite.com/llvm-project/rust-llvm-integrate-prototype/builds/15404#0184d95d-5a68-4db6-ad32-51ddbc3ab543/202-571

Author: matthiaskrgr

compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -205,7 +205,12 @@ enum class LLVMRustCodeModel {
   None,
 };
 
-static Optional<CodeModel::Model> fromRust(LLVMRustCodeModel Model) {
+#if LLVM_VERSION_LT(16, 0)
+static Optional<CodeModel::Model>
+#else
+static std::optional<CodeModel::Model>
+#endif
+fromRust(LLVMRustCodeModel Model) {
   switch (Model) {
   case LLVMRustCodeModel::Tiny:
     return CodeModel::Tiny;
@@ -638,7 +643,11 @@ LLVMRustOptimize(
     LLVMSelfProfileInitializeCallbacks(PIC,LlvmSelfProfiler,BeforePassCallback,AfterPassCallback);
   }
 
+#if LLVM_VERSION_LT(16, 0)
   Optional<PGOOptions> PGOOpt;
+#else
+  std::optional<PGOOptions> PGOOpt;
+#endif
   if (PGOGenPath) {
     assert(!PGOUsePath && !PGOSampleUsePath);
     PGOOpt = PGOOptions(PGOGenPath, "", "", PGOOptions::IRInstr,

compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp

@@ -17,7 +17,9 @@
 #include "llvm/Pass.h"
 #include "llvm/Bitcode/BitcodeWriter.h"
 #include "llvm/Support/Signals.h"
+#if LLVM_VERSION_LT(16, 0)
 #include "llvm/ADT/Optional.h"
+#endif
 
 #include <iostream>
 
@@ -708,7 +710,11 @@ enum class LLVMRustChecksumKind {
   SHA256,
 };
 
+#if LLVM_VERSION_LT(16, 0)
 static Optional<DIFile::ChecksumKind> fromRust(LLVMRustChecksumKind Kind) {
+#else
+static std::optional<DIFile::ChecksumKind> fromRust(LLVMRustChecksumKind Kind) {
+#endif
   switch (Kind) {
   case LLVMRustChecksumKind::None:
     return None;
@@ -787,8 +793,18 @@ extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateFile(
     const char *Filename, size_t FilenameLen,
     const char *Directory, size_t DirectoryLen, LLVMRustChecksumKind CSKind,
     const char *Checksum, size_t ChecksumLen) {
+
+#if LLVM_VERSION_LT(16, 0)
   Optional<DIFile::ChecksumKind> llvmCSKind = fromRust(CSKind);
+#else
+  std::optional<DIFile::ChecksumKind> llvmCSKind = fromRust(CSKind);
+#endif
+
+#if LLVM_VERSION_LT(16, 0)
   Optional<DIFile::ChecksumInfo<StringRef>> CSInfo{};
+#else
+  std::optional<DIFile::ChecksumInfo<StringRef>> CSInfo{};
+#endif
   if (llvmCSKind)
     CSInfo.emplace(*llvmCSKind, StringRef{Checksum, ChecksumLen});
   return wrap(Builder->createFile(StringRef(Filename, FilenameLen),