[llvm] annotate interfaces in llvm/Target for DLL export (llvm#143615)

## Purpose

This patch is one in a series of code-mods that annotate LLVM’s public
interface for export. This patch annotates the `llvm/Target` 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).

A sub-set 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 bulk of this change is manual additions of `LLVM_ABI` to
`LLVMInitializeX` functions defined in .cpp files under llvm/lib/Target.
Adding `LLVM_ABI` to the function implementation is required here
because they do not `#include "llvm/Support/TargetSelect.h"`, which
contains the declarations for this functions and was already updated
with `LLVM_ABI` in a previous patch. I considered patching these files
with `#include "llvm/Support/TargetSelect.h"` instead, but since
TargetSelect.h is a large file with a bunch of preprocessor x-macro
stuff in it I was concerned it would unnecessarily impact compile times.

In addition, a number of unit tests under llvm/unittests/Target required
additional dependencies to make them build correctly against the LLVM
DLL on Windows using MSVC.

## 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/Target/CGPassBuilderOption.h

@@ -15,6 +15,7 @@
 #define LLVM_TARGET_CGPASSBUILDEROPTION_H
 
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Target/TargetOptions.h"
 #include <optional>
 
@@ -82,7 +83,7 @@ struct CGPassBuilderOption {
   std::optional<bool> DebugifyCheckAndStripAll;
 };
 
-CGPassBuilderOption getCGPassBuilderOption();
+LLVM_ABI CGPassBuilderOption getCGPassBuilderOption();
 
 } // namespace llvm
 

llvm/include/llvm/Target/TargetLoweringObjectFile.h

@@ -16,6 +16,7 @@
 
 #include "llvm/MC/MCObjectFileInfo.h"
 #include "llvm/MC/MCRegister.h"
+#include "llvm/Support/Compiler.h"
 #include <cstdint>
 
 namespace llvm {
@@ -43,7 +44,7 @@ class StringRef;
 class TargetMachine;
 class DSOLocalEquivalent;
 
-class TargetLoweringObjectFile : public MCObjectFileInfo {
+class LLVM_ABI TargetLoweringObjectFile : public MCObjectFileInfo {
   /// Name-mangler for global names.
   Mangler *Mang = nullptr;
 

llvm/include/llvm/Target/TargetMachine.h

@@ -19,6 +19,7 @@
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/Error.h"
 #include "llvm/Support/PGOOptions.h"
 #include "llvm/Target/CGPassBuilderOption.h"
@@ -28,7 +29,7 @@
 #include <string>
 #include <utility>
 
-extern llvm::cl::opt<bool> NoKernelInfoEndLTO;
+extern LLVM_ABI llvm::cl::opt<bool> NoKernelInfoEndLTO;
 
 namespace llvm {
 
@@ -78,7 +79,7 @@ struct MachineFunctionInfo;
 /// machine.  All target-specific information should be accessible through this
 /// interface.
 ///
-class TargetMachine {
+class LLVM_ABI TargetMachine {
 protected: // Can only create subclasses.
   TargetMachine(const Target &T, StringRef DataLayoutString,
                 const Triple &TargetTriple, StringRef CPU, StringRef FS,

llvm/include/llvm/Target/TargetOptions.h

@@ -16,6 +16,7 @@
 
 #include "llvm/ADT/FloatingPointMode.h"
 #include "llvm/MC/MCTargetOptions.h"
+#include "llvm/Support/Compiler.h"
 
 #include <memory>
 
@@ -158,12 +159,12 @@ class TargetOptions {
 
   /// DisableFramePointerElim - This returns true if frame pointer elimination
   /// optimization should be disabled for the given machine function.
-  bool DisableFramePointerElim(const MachineFunction &MF) const;
+  LLVM_ABI bool DisableFramePointerElim(const MachineFunction &MF) const;
 
   /// FramePointerIsReserved - This returns true if the frame pointer must
   /// always either point to a new frame record or be un-modified in the given
   /// function.
-  bool FramePointerIsReserved(const MachineFunction &MF) const;
+  LLVM_ABI bool FramePointerIsReserved(const MachineFunction &MF) const;
 
   /// If greater than 0, override the default value of
   /// MCAsmInfo::BinutilsVersion.
@@ -219,7 +220,7 @@ class TargetOptions {
   /// truncations).  If this is enabled (set to true), the code generator must
   /// assume that the rounding mode may dynamically change.
   unsigned HonorSignDependentRoundingFPMathOption : 1;
-  bool HonorSignDependentRoundingFPMath() const;
+  LLVM_ABI bool HonorSignDependentRoundingFPMath() const;
 
   /// NoZerosInBSS - By default some codegens place zero-initialized data to
   /// .bss section. This flag disables such behaviour (necessary, e.g. for
@@ -346,7 +347,7 @@ class TargetOptions {
   unsigned EnableDebugEntryValues : 1;
   /// NOTE: There are targets that still do not support the debug entry values
   /// production.
-  bool ShouldEmitDebugEntryValues() const;
+  LLVM_ABI bool ShouldEmitDebugEntryValues() const;
 
   // When set to true, use experimental new debug variable location tracking,
   // which seeks to follow the values of variables rather than their location,
@@ -450,7 +451,7 @@ class TargetOptions {
 
   DenormalMode getRawFP32DenormalMode() const { return FP32DenormalMode; }
 
-  DenormalMode getDenormalMode(const fltSemantics &FPType) const;
+  LLVM_ABI DenormalMode getDenormalMode(const fltSemantics &FPType) const;
 
   /// What exception model to use
   ExceptionHandling ExceptionModel = ExceptionHandling::None;

llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp

@@ -58,6 +58,7 @@
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetMachine.h"
@@ -3534,7 +3535,8 @@ INITIALIZE_PASS(AArch64AsmPrinter, "aarch64-asm-printer",
                 "AArch64 Assembly Printer", false, false)
 
 // Force static initialization.
-extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeAArch64AsmPrinter() {
+extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
+LLVMInitializeAArch64AsmPrinter() {
   RegisterAsmPrinter<AArch64AsmPrinter> X(getTheAArch64leTarget());
   RegisterAsmPrinter<AArch64AsmPrinter> Y(getTheAArch64beTarget());
   RegisterAsmPrinter<AArch64AsmPrinter> Z(getTheARM64Target());

llvm/lib/Target/AArch64/AArch64TargetMachine.cpp

@@ -44,6 +44,7 @@
 #include "llvm/Passes/PassBuilder.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Target/TargetLoweringObjectFile.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/TargetParser/Triple.h"
@@ -223,7 +224,8 @@ static cl::opt<bool>
                            cl::desc("Enable Machine Pipeliner for AArch64"),
                            cl::init(false), cl::Hidden);
 
-extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeAArch64Target() {
+extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
+LLVMInitializeAArch64Target() {
   // Register the target.
   RegisterTargetMachine<AArch64leTargetMachine> X(getTheAArch64leTarget());
   RegisterTargetMachine<AArch64beTargetMachine> Y(getTheAArch64beTarget());

llvm/lib/Target/AArch64/AsmParser/AArch64AsmParser.cpp

@@ -8322,7 +8322,8 @@ bool AArch64AsmParser::classifySymbolRef(const MCExpr *Expr,
 }
 
 /// Force static initialization.
-extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeAArch64AsmParser() {
+extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
+LLVMInitializeAArch64AsmParser() {
   RegisterMCAsmParser<AArch64AsmParser> X(getTheAArch64leTarget());
   RegisterMCAsmParser<AArch64AsmParser> Y(getTheAArch64beTarget());
   RegisterMCAsmParser<AArch64AsmParser> Z(getTheARM64Target());

llvm/lib/Target/AArch64/Disassembler/AArch64Disassembler.cpp

@@ -310,7 +310,8 @@ createAArch64ExternalSymbolizer(const Triple &TT, LLVMOpInfoCallback GetOpInfo,
                                        SymbolLookUp, DisInfo);
 }
 
-extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeAArch64Disassembler() {
+extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
+LLVMInitializeAArch64Disassembler() {
   TargetRegistry::RegisterMCDisassembler(getTheAArch64leTarget(),
                                          createAArch64Disassembler);
   TargetRegistry::RegisterMCDisassembler(getTheAArch64beTarget(),

llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp

@@ -27,6 +27,7 @@
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/TargetRegistry.h"
+#include "llvm/Support/Compiler.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/TargetParser/AArch64TargetParser.h"
@@ -503,7 +504,8 @@ static MCInstrAnalysis *createAArch64InstrAnalysis(const MCInstrInfo *Info) {
 }
 
 // Force static initialization.
-extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeAArch64TargetMC() {
+extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
+LLVMInitializeAArch64TargetMC() {
   for (Target *T : {&getTheAArch64leTarget(), &getTheAArch64beTarget(),
                     &getTheAArch64_32Target(), &getTheARM64Target(),
                     &getTheARM64_32Target()}) {

llvm/lib/Target/AArch64/TargetInfo/AArch64TargetInfo.cpp

@@ -8,6 +8,7 @@
 
 #include "TargetInfo/AArch64TargetInfo.h"
 #include "llvm/MC/TargetRegistry.h"
+#include "llvm/Support/Compiler.h"
 
 using namespace llvm;
 Target &llvm::getTheAArch64leTarget() {
@@ -31,7 +32,8 @@ Target &llvm::getTheARM64_32Target() {
   return TheARM64_32Target;
 }
 
-extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeAArch64TargetInfo() {
+extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void
+LLVMInitializeAArch64TargetInfo() {
   // Now register the "arm64" name for use with "-march". We don't want it to
   // take possession of the Triple::aarch64 tags though.
   TargetRegistry::RegisterTarget(getTheARM64Target(), "arm64",