[llvm] annotate interfaces in llvm/LTO for DLL export (llvm#142499)

## Purpose

This patch is one in a series of code-mods that annotate LLVM’s public
interface for export. This patch annotates the `llvm/LTO` library. These
annotations currently have no meaningful impact on the LLVM build;
however, they are a prerequisite to support an LLVM Windows DLL (shared
library) build.

## Background

This effort is tracked in llvm#109483. Additional context is provided in
[this
discourse](https://discourse.llvm.org/t/psa-annotating-llvm-public-interface/85307),
and documentation for `LLVM_ABI` and related annotations is found in the
LLVM repo
[here](https://github.com/llvm/llvm-project/blob/main/llvm/docs/InterfaceExportAnnotations.rst).

The bulk of these changes were generated automatically using the
[Interface Definition Scanner (IDS)](https://github.com/compnerd/ids)
tool, followed formatting with `git clang-format`.

The following manual adjustments were also applied after running IDS on
Linux:
- Add `LLVM_ABI` to a small number of symbols that require export but
are not declared in headers

## Validation

Local builds and tests to validate cross-platform compatibility. This
included llvm, clang, and lldb on the following configurations:

- Windows with MSVC
- Windows with Clang
- Linux with GCC
- Linux with Clang
- Darwin with Clang

Author: andrurogerz

llvm/include/llvm/InterfaceStub/ELFObjHandler.h

@@ -14,6 +14,7 @@
 #define LLVM_INTERFACESTUB_ELFOBJHANDLER_H
 
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/MemoryBufferRef.h"
 #include <memory>
@@ -24,7 +25,7 @@ namespace ifs {
 struct IFSStub;
 
 /// Attempt to read a binary ELF file from a MemoryBuffer.
-Expected<std::unique_ptr<IFSStub>> readELFFile(MemoryBufferRef Buf);
+LLVM_ABI Expected<std::unique_ptr<IFSStub>> readELFFile(MemoryBufferRef Buf);
 
 /// Attempt to write a binary ELF stub.
 /// This function determines appropriate ELFType using the passed ELFTarget and
@@ -34,8 +35,8 @@ Expected<std::unique_ptr<IFSStub>> readELFFile(MemoryBufferRef Buf);
 /// @param Stub Source ELFStub to generate a binary ELF stub from.
 /// @param WriteIfChanged Whether or not to preserve timestamp if
 ///        the output stays the same.
-Error writeBinaryStub(StringRef FilePath, const IFSStub &Stub,
-                      bool WriteIfChanged = false);
+LLVM_ABI Error writeBinaryStub(StringRef FilePath, const IFSStub &Stub,
+                               bool WriteIfChanged = false);
 
 } // end namespace ifs
 } // end namespace llvm

llvm/include/llvm/InterfaceStub/IFSHandler.h

@@ -16,6 +16,7 @@
 #define LLVM_INTERFACESTUB_IFSHANDLER_H
 
 #include "IFSStub.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/VersionTuple.h"
 #include <memory>
@@ -36,29 +37,30 @@ struct IFSStub;
 const VersionTuple IFSVersionCurrent(3, 0);
 
 /// Attempts to read an IFS interface file from a StringRef buffer.
-Expected<std::unique_ptr<IFSStub>> readIFSFromBuffer(StringRef Buf);
+LLVM_ABI Expected<std::unique_ptr<IFSStub>> readIFSFromBuffer(StringRef Buf);
 
 /// Attempts to write an IFS interface file to a raw_ostream.
-Error writeIFSToOutputStream(raw_ostream &OS, const IFSStub &Stub);
+LLVM_ABI Error writeIFSToOutputStream(raw_ostream &OS, const IFSStub &Stub);
 
 /// Override the target platform inforation in the text stub.
-Error overrideIFSTarget(IFSStub &Stub, std::optional<IFSArch> OverrideArch,
-                        std::optional<IFSEndiannessType> OverrideEndianness,
-                        std::optional<IFSBitWidthType> OverrideBitWidth,
-                        std::optional<std::string> OverrideTriple);
+LLVM_ABI Error
+overrideIFSTarget(IFSStub &Stub, std::optional<IFSArch> OverrideArch,
+                  std::optional<IFSEndiannessType> OverrideEndianness,
+                  std::optional<IFSBitWidthType> OverrideBitWidth,
+                  std::optional<std::string> OverrideTriple);
 
 /// Validate the target platform inforation in the text stub.
-Error validateIFSTarget(IFSStub &Stub, bool ParseTriple);
+LLVM_ABI Error validateIFSTarget(IFSStub &Stub, bool ParseTriple);
 
 /// Strips target platform information from the text stub.
-void stripIFSTarget(IFSStub &Stub, bool StripTriple, bool StripArch,
-                    bool StripEndianness, bool StripBitWidth);
+LLVM_ABI void stripIFSTarget(IFSStub &Stub, bool StripTriple, bool StripArch,
+                             bool StripEndianness, bool StripBitWidth);
 
-Error filterIFSSyms(IFSStub &Stub, bool StripUndefined,
-                    const std::vector<std::string> &Exclude = {});
+LLVM_ABI Error filterIFSSyms(IFSStub &Stub, bool StripUndefined,
+                             const std::vector<std::string> &Exclude = {});
 
 /// Parse llvm triple string into a IFSTarget struct.
-IFSTarget parseTriple(StringRef TripleStr);
+LLVM_ABI IFSTarget parseTriple(StringRef TripleStr);
 
 } // end namespace ifs
 } // end namespace llvm

llvm/include/llvm/InterfaceStub/IFSStub.h

@@ -14,6 +14,7 @@
 #ifndef LLVM_INTERFACESTUB_IFSSTUB_H
 #define LLVM_INTERFACESTUB_IFSSTUB_H
 
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/VersionTuple.h"
 #include <optional>
 #include <vector>
@@ -69,7 +70,7 @@ struct IFSTarget {
   std::optional<IFSEndiannessType> Endianness;
   std::optional<IFSBitWidthType> BitWidth;
 
-  bool empty();
+  LLVM_ABI bool empty();
 };
 
 inline bool operator==(const IFSTarget &Lhs, const IFSTarget &Rhs) {
@@ -95,8 +96,8 @@ struct IFSStub {
   std::vector<IFSSymbol> Symbols;
 
   IFSStub() = default;
-  IFSStub(const IFSStub &Stub);
-  IFSStub(IFSStub &&Stub);
+  LLVM_ABI IFSStub(const IFSStub &Stub);
+  LLVM_ABI IFSStub(IFSStub &&Stub);
   virtual ~IFSStub() = default;
 };
 
@@ -107,50 +108,50 @@ struct IFSStub {
 // structure can be used for 2 different yaml schema.
 struct IFSStubTriple : IFSStub {
   IFSStubTriple() = default;
-  IFSStubTriple(const IFSStub &Stub);
-  IFSStubTriple(const IFSStubTriple &Stub);
-  IFSStubTriple(IFSStubTriple &&Stub);
+  LLVM_ABI IFSStubTriple(const IFSStub &Stub);
+  LLVM_ABI IFSStubTriple(const IFSStubTriple &Stub);
+  LLVM_ABI IFSStubTriple(IFSStubTriple &&Stub);
 };
 
 /// This function convert bit width type from IFS enum to ELF format
 /// Currently, ELFCLASS32 and ELFCLASS64 are supported.
 ///
 /// @param BitWidth IFS bit width type.
-uint8_t convertIFSBitWidthToELF(IFSBitWidthType BitWidth);
+LLVM_ABI uint8_t convertIFSBitWidthToELF(IFSBitWidthType BitWidth);
 
 /// This function convert endianness type from IFS enum to ELF format
 /// Currently, ELFDATA2LSB and ELFDATA2MSB are supported.
 ///
 /// @param Endianness IFS endianness type.
-uint8_t convertIFSEndiannessToELF(IFSEndiannessType Endianness);
+LLVM_ABI uint8_t convertIFSEndiannessToELF(IFSEndiannessType Endianness);
 
 /// This function convert symbol type from IFS enum to ELF format
 /// Currently, STT_NOTYPE, STT_OBJECT, STT_FUNC, and STT_TLS are supported.
 ///
 /// @param SymbolType IFS symbol type.
-uint8_t convertIFSSymbolTypeToELF(IFSSymbolType SymbolType);
+LLVM_ABI uint8_t convertIFSSymbolTypeToELF(IFSSymbolType SymbolType);
 
 /// This function extracts ELF bit width from e_ident[EI_CLASS] of an ELF file
 /// Currently, ELFCLASS32 and ELFCLASS64 are supported.
 /// Other endianness types are mapped to IFSBitWidthType::Unknown.
 ///
 /// @param BitWidth e_ident[EI_CLASS] value to extract bit width from.
-IFSBitWidthType convertELFBitWidthToIFS(uint8_t BitWidth);
+LLVM_ABI IFSBitWidthType convertELFBitWidthToIFS(uint8_t BitWidth);
 
 /// This function extracts ELF endianness from e_ident[EI_DATA] of an ELF file
 /// Currently, ELFDATA2LSB and ELFDATA2MSB are supported.
 /// Other endianness types are mapped to IFSEndiannessType::Unknown.
 ///
 /// @param Endianness e_ident[EI_DATA] value to extract endianness type from.
-IFSEndiannessType convertELFEndiannessToIFS(uint8_t Endianness);
+LLVM_ABI IFSEndiannessType convertELFEndiannessToIFS(uint8_t Endianness);
 
 /// This function extracts symbol type from a symbol's st_info member and
 /// maps it to an IFSSymbolType enum.
 /// Currently, STT_NOTYPE, STT_OBJECT, STT_FUNC, and STT_TLS are supported.
 /// Other symbol types are mapped to IFSSymbolType::Unknown.
 ///
 /// @param SymbolType Binary symbol st_info to extract symbol type from.
-IFSSymbolType convertELFSymbolTypeToIFS(uint8_t SymbolType);
+LLVM_ABI IFSSymbolType convertELFSymbolTypeToIFS(uint8_t SymbolType);
 } // namespace ifs
 } // end namespace llvm
 

llvm/include/llvm/LTO/Config.h

@@ -22,6 +22,7 @@
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/Passes/PassBuilder.h"
 #include "llvm/Support/CodeGen.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Target/TargetOptions.h"
 
 #include <functional>
@@ -277,9 +278,9 @@ struct Config {
   ///
   /// SaveTempsArgs can be specified to select which temps to save.
   /// If SaveTempsArgs is not provided, all temps are saved.
-  Error addSaveTemps(std::string OutputFileName,
-                     bool UseInputModulePath = false,
-                     const DenseSet<StringRef> &SaveTempsArgs = {});
+  LLVM_ABI Error addSaveTemps(std::string OutputFileName,
+                              bool UseInputModulePath = false,
+                              const DenseSet<StringRef> &SaveTempsArgs = {});
 };
 
 struct LTOLLVMDiagnosticHandler : public DiagnosticHandler {