diff --git a/llvm/include/llvm/CGData/CodeGenData.h b/llvm/include/llvm/CGData/CodeGenData.h
index 0e7dd2f5b5c1a..ad7fa579f7508 100644
--- a/llvm/include/llvm/CGData/CodeGenData.h
+++ b/llvm/include/llvm/CGData/CodeGenData.h
@@ -23,6 +23,7 @@
 #include "llvm/IR/Module.h"
 #include "llvm/Object/ObjectFile.h"
 #include "llvm/Support/Caching.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/TargetParser/Triple.h"
 #include <mutex>
@@ -34,9 +35,9 @@ enum CGDataSectKind {
 #include "llvm/CGData/CodeGenData.inc"
 };
 
-std::string getCodeGenDataSectionName(CGDataSectKind CGSK,
-                                      Triple::ObjectFormatType OF,
-                                      bool AddSegmentInfo = true);
+LLVM_ABI std::string getCodeGenDataSectionName(CGDataSectKind CGSK,
+                                               Triple::ObjectFormatType OF,
+                                               bool AddSegmentInfo = true);
 
 enum class CGDataKind {
   Unknown = 0x0,
@@ -47,7 +48,7 @@ enum class CGDataKind {
   LLVM_MARK_AS_BITMASK_ENUM(/*LargestValue=*/StableFunctionMergingMap)
 };
 
-const std::error_category &cgdata_category();
+LLVM_ABI const std::error_category &cgdata_category();
 
 enum class cgdata_error {
   success = 0,
@@ -63,7 +64,7 @@ inline std::error_code make_error_code(cgdata_error E) {
   return std::error_code(static_cast<int>(E), cgdata_category());
 }
 
-class CGDataError : public ErrorInfo<CGDataError> {
+class LLVM_ABI CGDataError : public ErrorInfo<CGDataError> {
 public:
   CGDataError(cgdata_error Err, const Twine &ErrStr = Twine())
       : Err(Err), Msg(ErrStr.str()) {
@@ -130,7 +131,7 @@ class CodeGenData {
 public:
   ~CodeGenData() = default;
 
-  static CodeGenData &getInstance();
+  LLVM_ABI static CodeGenData &getInstance();
 
   /// Returns true if we have a valid outlined hash tree.
   bool hasOutlinedHashTree() {
@@ -245,8 +246,8 @@ struct StreamCacheData {
 /// \p Task represents the partition number in the parallel code generation
 /// process. \p AddStream is the callback used to add the serialized module to
 /// the stream.
-void saveModuleForTwoRounds(const Module &TheModule, unsigned Task,
-                            AddStreamFn AddStream);
+LLVM_ABI void saveModuleForTwoRounds(const Module &TheModule, unsigned Task,
+                                     AddStreamFn AddStream);
 
 /// Load the optimized bitcode module for the second codegen round.
 /// \p OrigModule is the original bitcode module.
@@ -254,18 +255,18 @@ void saveModuleForTwoRounds(const Module &TheModule, unsigned Task,
 /// process. \p Context provides the environment settings for module operations.
 /// \p IRFiles contains optimized bitcode module files needed for loading.
 /// \return A unique_ptr to the loaded Module, or nullptr if loading fails.
-std::unique_ptr<Module> loadModuleForTwoRounds(BitcodeModule &OrigModule,
-                                               unsigned Task,
-                                               LLVMContext &Context,
-                                               ArrayRef<StringRef> IRFiles);
+LLVM_ABI std::unique_ptr<Module>
+loadModuleForTwoRounds(BitcodeModule &OrigModule, unsigned Task,
+                       LLVMContext &Context, ArrayRef<StringRef> IRFiles);
 
 /// Merge the codegen data from the scratch objects \p ObjectFiles from the
 /// first codegen round.
 /// \return the combined hash of the merged codegen data.
-Expected<stable_hash> mergeCodeGenData(ArrayRef<StringRef> ObjectFiles);
+LLVM_ABI Expected<stable_hash>
+mergeCodeGenData(ArrayRef<StringRef> ObjectFiles);
 
-void warn(Error E, StringRef Whence = "");
-void warn(Twine Message, StringRef Whence = "", StringRef Hint = "");
+LLVM_ABI void warn(Error E, StringRef Whence = "");
+LLVM_ABI void warn(Twine Message, StringRef Whence = "", StringRef Hint = "");
 
 } // end namespace cgdata
 
@@ -297,7 +298,7 @@ struct Header {
   // the new field is read correctly.
 
   // Reads a header struct from the buffer.
-  static Expected<Header> readFromBuffer(const unsigned char *Curr);
+  LLVM_ABI static Expected<Header> readFromBuffer(const unsigned char *Curr);
 };
 
 } // end namespace IndexedCGData
diff --git a/llvm/include/llvm/CGData/CodeGenDataReader.h b/llvm/include/llvm/CGData/CodeGenDataReader.h
index 085dd6dd747c9..f915ce0afcd7f 100644
--- a/llvm/include/llvm/CGData/CodeGenDataReader.h
+++ b/llvm/include/llvm/CGData/CodeGenDataReader.h
@@ -16,6 +16,7 @@
 #include "llvm/CGData/CodeGenData.h"
 #include "llvm/CGData/OutlinedHashTreeRecord.h"
 #include "llvm/CGData/StableFunctionMapRecord.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/LineIterator.h"
 #include "llvm/Support/VirtualFileSystem.h"
 
@@ -49,12 +50,12 @@ class CodeGenDataReader {
 
   /// Factory method to create an appropriately typed reader for the given
   /// codegen data file path and file system.
-  static Expected<std::unique_ptr<CodeGenDataReader>>
+  LLVM_ABI static Expected<std::unique_ptr<CodeGenDataReader>>
   create(const Twine &Path, vfs::FileSystem &FS);
 
   /// Factory method to create an appropriately typed reader for the given
   /// memory buffer.
-  static Expected<std::unique_ptr<CodeGenDataReader>>
+  LLVM_ABI static Expected<std::unique_ptr<CodeGenDataReader>>
   create(std::unique_ptr<MemoryBuffer> Buffer);
 
   /// Extract the cgdata embedded in sections from the given object file and
@@ -62,7 +63,7 @@ class CodeGenDataReader {
   /// is used by `llvm-cgdata --merge` or ThinLTO's two-codegen rounds.
   /// Optionally, \p CombinedHash can be used to compuate the combined hash of
   /// the merged data.
-  static Error
+  LLVM_ABI static Error
   mergeFromObjectFile(const object::ObjectFile *Obj,
                       OutlinedHashTreeRecord &GlobalOutlineRecord,
                       StableFunctionMapRecord &GlobalFunctionMapRecord,
@@ -98,7 +99,7 @@ class CodeGenDataReader {
   Error success() { return error(cgdata_error::success); }
 };
 
-class IndexedCodeGenDataReader : public CodeGenDataReader {
+class LLVM_ABI IndexedCodeGenDataReader : public CodeGenDataReader {
   /// The codegen data file contents.
   std::unique_ptr<MemoryBuffer> DataBuffer;
   /// The header
@@ -139,7 +140,7 @@ class IndexedCodeGenDataReader : public CodeGenDataReader {
 /// codegen data is recorded. `#` is used to indicate a comment.
 /// The subsequent data is a YAML format per each codegen data in order.
 /// Currently, it only has a function outlined hash tree.
-class TextCodeGenDataReader : public CodeGenDataReader {
+class LLVM_ABI TextCodeGenDataReader : public CodeGenDataReader {
   /// The codegen data file contents.
   std::unique_ptr<MemoryBuffer> DataBuffer;
   /// Iterator over the profile data.
diff --git a/llvm/include/llvm/CGData/CodeGenDataWriter.h b/llvm/include/llvm/CGData/CodeGenDataWriter.h
index 1c4247608999a..faef6beb30aa6 100644
--- a/llvm/include/llvm/CGData/CodeGenDataWriter.h
+++ b/llvm/include/llvm/CGData/CodeGenDataWriter.h
@@ -16,6 +16,7 @@
 #include "llvm/CGData/CodeGenData.h"
 #include "llvm/CGData/OutlinedHashTreeRecord.h"
 #include "llvm/CGData/StableFunctionMapRecord.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/EndianStream.h"
 #include "llvm/Support/Error.h"
 
@@ -45,7 +46,7 @@ class CGDataOStream {
   // \c patch can only be called when all data is written and flushed.
   // For raw_string_ostream, the patch is done on the target string
   // directly and it won't be reflected in the stream's internal buffer.
-  void patch(ArrayRef<CGDataPatchItem> P);
+  LLVM_ABI void patch(ArrayRef<CGDataPatchItem> P);
 
   // If \c OS is an instance of \c raw_fd_ostream, this field will be
   // true. Otherwise, \c OS will be an raw_string_ostream.
@@ -69,16 +70,16 @@ class CodeGenDataWriter {
   ~CodeGenDataWriter() = default;
 
   /// Add the outlined hash tree record. The input hash tree is released.
-  void addRecord(OutlinedHashTreeRecord &Record);
+  LLVM_ABI void addRecord(OutlinedHashTreeRecord &Record);
 
   /// Add the stable function map record. The input function map is released.
-  void addRecord(StableFunctionMapRecord &Record);
+  LLVM_ABI void addRecord(StableFunctionMapRecord &Record);
 
   /// Write the codegen data to \c OS
-  Error write(raw_fd_ostream &OS);
+  LLVM_ABI Error write(raw_fd_ostream &OS);
 
   /// Write the codegen data in text format to \c OS
-  Error writeText(raw_fd_ostream &OS);
+  LLVM_ABI Error writeText(raw_fd_ostream &OS);
 
   /// Return the attributes of the current CGData.
   CGDataKind getCGDataKind() const { return DataKind; }
diff --git a/llvm/include/llvm/CGData/OutlinedHashTree.h b/llvm/include/llvm/CGData/OutlinedHashTree.h
index 9ab36df863eef..d994b68f33ee4 100644
--- a/llvm/include/llvm/CGData/OutlinedHashTree.h
+++ b/llvm/include/llvm/CGData/OutlinedHashTree.h
@@ -18,6 +18,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/StableHashing.h"
 #include "llvm/ObjectYAML/YAML.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/raw_ostream.h"
 
 #include <unordered_map>
@@ -54,9 +55,9 @@ class OutlinedHashTree {
   /// the source and the stable_hash of the sink for an edge. These generic
   /// callbacks can be used to traverse a OutlinedHashTree for the purpose of
   /// print debugging or serializing it.
-  void walkGraph(NodeCallbackFn CallbackNode,
-                 EdgeCallbackFn CallbackEdge = nullptr,
-                 bool SortedWalk = false) const;
+  LLVM_ABI void walkGraph(NodeCallbackFn CallbackNode,
+                          EdgeCallbackFn CallbackEdge = nullptr,
+                          bool SortedWalk = false) const;
 
   /// Release all hash nodes except the root hash node.
   void clear() {
@@ -71,10 +72,10 @@ class OutlinedHashTree {
   /// \p GetTerminalCountOnly is true, it only counts the terminal nodes
   /// (meaning it returns the the number of hash sequences in the
   /// OutlinedHashTree).
-  size_t size(bool GetTerminalCountOnly = false) const;
+  LLVM_ABI size_t size(bool GetTerminalCountOnly = false) const;
 
   /// \returns the depth of a OutlinedHashTree by traversing it.
-  size_t depth() const;
+  LLVM_ABI size_t depth() const;
 
   /// \returns the root hash node of a OutlinedHashTree.
   const HashNode *getRoot() const { return &Root; }
@@ -82,13 +83,13 @@ class OutlinedHashTree {
 
   /// Inserts a \p Sequence into the this tree. The last node in the sequence
   /// will increase Terminals.
-  void insert(const HashSequencePair &SequencePair);
+  LLVM_ABI void insert(const HashSequencePair &SequencePair);
 
   /// Merge a \p OtherTree into this Tree.
-  void merge(const OutlinedHashTree *OtherTree);
+  LLVM_ABI void merge(const OutlinedHashTree *OtherTree);
 
   /// \returns the matching count if \p Sequence exists in the OutlinedHashTree.
-  std::optional<unsigned> find(const HashSequence &Sequence) const;
+  LLVM_ABI std::optional<unsigned> find(const HashSequence &Sequence) const;
 
 private:
   HashNode Root;
diff --git a/llvm/include/llvm/CGData/OutlinedHashTreeRecord.h b/llvm/include/llvm/CGData/OutlinedHashTreeRecord.h
index dd599ff6a7a62..d09218dbda73d 100644
--- a/llvm/include/llvm/CGData/OutlinedHashTreeRecord.h
+++ b/llvm/include/llvm/CGData/OutlinedHashTreeRecord.h
@@ -17,6 +17,7 @@
 #define LLVM_CGDATA_OUTLINEDHASHTREERECORD_H
 
 #include "llvm/CGData/OutlinedHashTree.h"
+#include "llvm/Support/Compiler.h"
 
 namespace llvm {
 
@@ -40,13 +41,13 @@ struct OutlinedHashTreeRecord {
       : HashTree(std::move(HashTree)) {};
 
   /// Serialize the outlined hash tree to a raw_ostream.
-  void serialize(raw_ostream &OS) const;
+  LLVM_ABI void serialize(raw_ostream &OS) const;
   /// Deserialize the outlined hash tree from a raw_ostream.
-  void deserialize(const unsigned char *&Ptr);
+  LLVM_ABI void deserialize(const unsigned char *&Ptr);
   /// Serialize the outlined hash tree to a YAML stream.
-  void serializeYAML(yaml::Output &YOS) const;
+  LLVM_ABI void serializeYAML(yaml::Output &YOS) const;
   /// Deserialize the outlined hash tree from a YAML stream.
-  void deserializeYAML(yaml::Input &YIS);
+  LLVM_ABI void deserializeYAML(yaml::Input &YIS);
 
   /// Merge the other outlined hash tree into this one.
   void merge(const OutlinedHashTreeRecord &Other) {
diff --git a/llvm/include/llvm/CGData/StableFunctionMap.h b/llvm/include/llvm/CGData/StableFunctionMap.h
index a3a85b92c3b30..bcb72e8216973 100644
--- a/llvm/include/llvm/CGData/StableFunctionMap.h
+++ b/llvm/include/llvm/CGData/StableFunctionMap.h
@@ -19,6 +19,7 @@
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/IR/StructuralHash.h"
+#include "llvm/Support/Compiler.h"
 
 namespace llvm {
 
@@ -82,18 +83,18 @@ struct StableFunctionMap {
 
   /// Get an existing ID associated with the given name or create a new ID if it
   /// doesn't exist.
-  unsigned getIdOrCreateForName(StringRef Name);
+  LLVM_ABI unsigned getIdOrCreateForName(StringRef Name);
 
   /// Get the name associated with a given ID
-  std::optional<std::string> getNameForId(unsigned Id) const;
+  LLVM_ABI std::optional<std::string> getNameForId(unsigned Id) const;
 
   /// Insert a `StableFunction` object into the function map. This method
   /// handles the uniquing of string names and create a `StableFunctionEntry`
   /// for insertion.
-  void insert(const StableFunction &Func);
+  LLVM_ABI void insert(const StableFunction &Func);
 
   /// Merge a \p OtherMap into this function map.
-  void merge(const StableFunctionMap &OtherMap);
+  LLVM_ABI void merge(const StableFunctionMap &OtherMap);
 
   /// \returns true if there is no stable function entry.
   bool empty() const { return size() == 0; }
@@ -107,10 +108,10 @@ struct StableFunctionMap {
 
   /// \returns the size of StableFunctionMap.
   /// \p Type is the type of size to return.
-  size_t size(SizeType Type = UniqueHashCount) const;
+  LLVM_ABI size_t size(SizeType Type = UniqueHashCount) const;
 
   /// Finalize the stable function map by trimming content.
-  void finalize(bool SkipTrim = false);
+  LLVM_ABI void finalize(bool SkipTrim = false);
 
 private:
   /// Insert a `StableFunctionEntry` into the function map directly. This
diff --git a/llvm/include/llvm/CGData/StableFunctionMapRecord.h b/llvm/include/llvm/CGData/StableFunctionMapRecord.h
index f9b3ed7c646d6..d4d3ffa06ad25 100644
--- a/llvm/include/llvm/CGData/StableFunctionMapRecord.h
+++ b/llvm/include/llvm/CGData/StableFunctionMapRecord.h
@@ -18,6 +18,7 @@
 
 #include "llvm/CGData/StableFunctionMap.h"
 #include "llvm/ObjectYAML/YAML.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/raw_ostream.h"
 
 namespace llvm {
@@ -34,19 +35,20 @@ struct StableFunctionMapRecord {
 
   /// A static helper function to serialize the stable function map without
   /// owning the stable function map.
-  static void serialize(raw_ostream &OS, const StableFunctionMap *FunctionMap);
+  LLVM_ABI static void serialize(raw_ostream &OS,
+                                 const StableFunctionMap *FunctionMap);
 
   /// Serialize the stable function map to a raw_ostream.
-  void serialize(raw_ostream &OS) const;
+  LLVM_ABI void serialize(raw_ostream &OS) const;
 
   /// Deserialize the stable function map from a raw_ostream.
-  void deserialize(const unsigned char *&Ptr);
+  LLVM_ABI void deserialize(const unsigned char *&Ptr);
 
   /// Serialize the stable function map to a YAML stream.
-  void serializeYAML(yaml::Output &YOS) const;
+  LLVM_ABI void serializeYAML(yaml::Output &YOS) const;
 
   /// Deserialize the stable function map from a YAML stream.
-  void deserializeYAML(yaml::Input &YIS);
+  LLVM_ABI void deserializeYAML(yaml::Input &YIS);
 
   /// Finalize the stable function map by trimming content.
   void finalize(bool SkipTrim = false) { FunctionMap->finalize(SkipTrim); }
diff --git a/llvm/include/llvm/CodeGen/AccelTable.h b/llvm/include/llvm/CodeGen/AccelTable.h
index f98e994b3f998..34c6fda7dcc17 100644
--- a/llvm/include/llvm/CodeGen/AccelTable.h
+++ b/llvm/include/llvm/CodeGen/AccelTable.h
@@ -21,6 +21,7 @@
 #include "llvm/CodeGen/DIE.h"
 #include "llvm/CodeGen/DwarfStringPoolEntry.h"
 #include "llvm/Support/Allocator.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/DJB.h"
 #include "llvm/Support/Debug.h"
 #include <cstdint>
@@ -174,12 +175,12 @@ class AccelTableBase {
   HashList Hashes;
   BucketList Buckets;
 
-  void computeBucketCount();
+  LLVM_ABI void computeBucketCount();
 
   AccelTableBase(HashFn *Hash) : Hash(Hash) {}
 
 public:
-  void finalize(AsmPrinter *Asm, StringRef Prefix);
+  LLVM_ABI void finalize(AsmPrinter *Asm, StringRef Prefix);
   ArrayRef<HashList> getBuckets() const { return Buckets; }
   uint32_t getBucketCount() const { return BucketCount; }
   uint32_t getUniqueHashCount() const { return UniqueHashCount; }
@@ -293,7 +294,8 @@ class DWARF5AccelTableData : public AccelTableData {
 public:
   static uint32_t hash(StringRef Name) { return caseFoldingDjbHash(Name); }
 
-  DWARF5AccelTableData(const DIE &Die, const uint32_t UnitID, const bool IsTU);
+  LLVM_ABI DWARF5AccelTableData(const DIE &Die, const uint32_t UnitID,
+                                const bool IsTU);
   DWARF5AccelTableData(const uint64_t DieOffset,
                        const std::optional<uint64_t> DefiningParentOffset,
                        const unsigned DieTag, const unsigned UnitID,
@@ -348,7 +350,8 @@ class DWARF5AccelTableData : public AccelTableData {
 
   /// If `Die` has a non-null parent and the parent is not a declaration,
   /// return its offset.
-  static std::optional<uint64_t> getDefiningParentDieOffset(const DIE &Die);
+  LLVM_ABI static std::optional<uint64_t>
+  getDefiningParentDieOffset(const DIE &Die);
 
 protected:
   std::variant<const DIE *, uint64_t> OffsetVal;
@@ -380,7 +383,7 @@ class DebugNamesAbbrev : public FoldingSetNode {
   /// Get DIE Tag.
   uint32_t getDieTag() const { return DieTag; }
   /// Used to gather unique data for the abbreviation folding set.
-  void Profile(FoldingSetNodeID &ID) const;
+  LLVM_ABI void Profile(FoldingSetNodeID &ID) const;
   /// Returns attributes for an abbreviation.
   const SmallVector<AttributeEncoding, 1> &getAttributes() const {
     return AttrVect;
@@ -409,9 +412,9 @@ class DWARF5AccelTable : public AccelTable<DWARF5AccelTableData> {
   /// Returns type units that were constructed.
   const TUVectorTy &getTypeUnitsSymbols() { return TUSymbolsOrHashes; }
   /// Add a type unit start symbol.
-  void addTypeUnitSymbol(DwarfTypeUnit &U);
+  LLVM_ABI void addTypeUnitSymbol(DwarfTypeUnit &U);
   /// Add a type unit Signature.
-  void addTypeUnitSignature(DwarfTypeUnit &U);
+  LLVM_ABI void addTypeUnitSignature(DwarfTypeUnit &U);
   /// Convert DIE entries to explicit offset.
   /// Needs to be called after DIE offsets are computed.
   void convertDieToOffset() {
@@ -437,9 +440,10 @@ class DWARF5AccelTable : public AccelTable<DWARF5AccelTableData> {
   }
 };
 
-void emitAppleAccelTableImpl(AsmPrinter *Asm, AccelTableBase &Contents,
-                             StringRef Prefix, const MCSymbol *SecBegin,
-                             ArrayRef<AppleAccelTableData::Atom> Atoms);
+LLVM_ABI void
+emitAppleAccelTableImpl(AsmPrinter *Asm, AccelTableBase &Contents,
+                        StringRef Prefix, const MCSymbol *SecBegin,
+                        ArrayRef<AppleAccelTableData::Atom> Atoms);
 
 /// Emit an Apple Accelerator Table consisting of entries in the specified
 /// AccelTable. The DataT template parameter should be derived from
@@ -451,15 +455,16 @@ void emitAppleAccelTable(AsmPrinter *Asm, AccelTable<DataT> &Contents,
   emitAppleAccelTableImpl(Asm, Contents, Prefix, SecBegin, DataT::Atoms);
 }
 
-void emitDWARF5AccelTable(AsmPrinter *Asm, DWARF5AccelTable &Contents,
-                          const DwarfDebug &DD,
-                          ArrayRef<std::unique_ptr<DwarfCompileUnit>> CUs);
+LLVM_ABI void
+emitDWARF5AccelTable(AsmPrinter *Asm, DWARF5AccelTable &Contents,
+                     const DwarfDebug &DD,
+                     ArrayRef<std::unique_ptr<DwarfCompileUnit>> CUs);
 
 /// Emit a DWARFv5 Accelerator Table consisting of entries in the specified
 /// AccelTable. The \p CUs contains either symbols keeping offsets to the
 /// start of compilation unit, either offsets to the start of compilation
 /// unit themselves.
-void emitDWARF5AccelTable(
+LLVM_ABI void emitDWARF5AccelTable(
     AsmPrinter *Asm, DWARF5Accel...
[truncated]