#include "LLVMWrapper.h"

#include "llvm-c/Analysis.h"
#include "llvm-c/Core.h"
#include "llvm-c/DebugInfo.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/BinaryFormat/Magic.h"
#include "llvm/Bitcode/BitcodeWriter.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DebugInfoMetadata.h"
#include "llvm/IR/DiagnosticHandler.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/DiagnosticPrinter.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicsARM.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/LLVMRemarkStreamer.h"
#include "llvm/IR/Mangler.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Value.h"
#include "llvm/Object/COFFImportFile.h"
#include "llvm/Remarks/RemarkFormat.h"
#include "llvm/Remarks/RemarkSerializer.h"
#include "llvm/Remarks/RemarkStreamer.h"
#include "llvm/Support/Compression.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/JSON.h"
#include "llvm/Support/ModRef.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/Timer.h"
#include "llvm/Support/ToolOutputFile.h"
#include <iostream>

// for raw `write` in the bad-alloc handler
#ifdef _MSC_VER
#include <io.h>
#else
#include <unistd.h>
#endif

//===----------------------------------------------------------------------===
//
// This file defines alternate interfaces to core functions that are more
// readily callable by Rust's FFI.
//
//===----------------------------------------------------------------------===

using namespace llvm;
using namespace llvm::sys;
using namespace llvm::object;

// This opcode is an LLVM detail that could hypothetically change (?), so
// verify that the hard-coded value in `dwarf_const.rs` still agrees with LLVM.
static_assert(dwarf::DW_OP_LLVM_fragment == 0x1000);

// LLVMAtomicOrdering is already an enum - don't create another
// one.
static AtomicOrdering fromRust(LLVMAtomicOrdering Ordering) {
  switch (Ordering) {
  case LLVMAtomicOrderingNotAtomic:
    return AtomicOrdering::NotAtomic;
  case LLVMAtomicOrderingUnordered:
    return AtomicOrdering::Unordered;
  case LLVMAtomicOrderingMonotonic:
    return AtomicOrdering::Monotonic;
  case LLVMAtomicOrderingAcquire:
    return AtomicOrdering::Acquire;
  case LLVMAtomicOrderingRelease:
    return AtomicOrdering::Release;
  case LLVMAtomicOrderingAcquireRelease:
    return AtomicOrdering::AcquireRelease;
  case LLVMAtomicOrderingSequentiallyConsistent:
    return AtomicOrdering::SequentiallyConsistent;
  }

  report_fatal_error("Invalid LLVMAtomicOrdering value!");
}

static LLVM_THREAD_LOCAL char *LastError;

// Custom error handler for fatal LLVM errors.
//
// Notably it exits the process with code 101, unlike LLVM's default of 1.
static void FatalErrorHandler(void *UserData, const char *Reason,
                              bool GenCrashDiag) {
  // Once upon a time we emitted "LLVM ERROR:" specifically to mimic LLVM. Then,
  // we developed crater and other tools which only expose logs, not error
  // codes. Use a more greppable prefix that will still match the "LLVM ERROR:"
  // prefix.
  std::cerr << "rustc-LLVM ERROR: " << Reason << std::endl;

  // Since this error handler exits the process, we have to run any cleanup that
  // LLVM would run after handling the error. This might change with an LLVM
  // upgrade.
  //
  // In practice, this will do nothing, because the only cleanup LLVM does is
  // to remove all files that were registered with it via a frontend calling
  // one of the `createOutputFile` family of functions in LLVM and passing true
  // to RemoveFileOnSignal, something that rustc does not do. However, it would
  // be... inadvisable to suddenly stop running these handlers, if LLVM gets
  // "interesting" ideas in the future about what cleanup should be done.
  // We might even find it useful for generating less artifacts.
  sys::RunInterruptHandlers();

  exit(101);
}

// Custom error handler for bad-alloc LLVM errors.
//
// It aborts the process without any further allocations, similar to LLVM's
// default except that may be configured to `throw std::bad_alloc()` instead.
static void BadAllocErrorHandler(void *UserData, const char *Reason,
                                 bool GenCrashDiag) {
  const char *OOM = "rustc-LLVM ERROR: out of memory\n";
  (void)!::write(2, OOM, strlen(OOM));
  (void)!::write(2, Reason, strlen(Reason));
  (void)!::write(2, "\n", 1);
  abort();
}

extern "C" void LLVMRustInstallErrorHandlers() {
  install_bad_alloc_error_handler(BadAllocErrorHandler);
  install_fatal_error_handler(FatalErrorHandler);
  install_out_of_memory_new_handler();
}

extern "C" void LLVMRustDisableSystemDialogsOnCrash() {
  sys::DisableSystemDialogsOnCrash();
}

extern "C" char *LLVMRustGetLastError(void) {
  char *Ret = LastError;
  LastError = nullptr;
  return Ret;
}

extern "C" void LLVMRustSetLastError(const char *Err) {
  free((void *)LastError);
  LastError = strdup(Err);
}

extern "C" LLVMContextRef LLVMRustContextCreate(bool shouldDiscardNames) {
  auto ctx = new LLVMContext();
  ctx->setDiscardValueNames(shouldDiscardNames);
  return wrap(ctx);
}

extern "C" void LLVMRustSetNormalizedTarget(LLVMModuleRef M,
                                            const char *Target) {
#if LLVM_VERSION_GE(21, 0)
  unwrap(M)->setTargetTriple(Triple(Triple::normalize(Target)));
#else
  unwrap(M)->setTargetTriple(Triple::normalize(Target));
#endif
}

extern "C" void LLVMRustPrintPassTimings(RustStringRef OutBuf) {
  auto OS = RawRustStringOstream(OutBuf);
  TimerGroup::printAll(OS);
}

extern "C" void LLVMRustPrintStatistics(RustStringRef OutBuf) {
  auto OS = RawRustStringOstream(OutBuf);
  llvm::PrintStatistics(OS);
}

extern "C" LLVMValueRef LLVMRustGetNamedValue(LLVMModuleRef M, const char *Name,
                                              size_t NameLen) {
  return wrap(unwrap(M)->getNamedValue(StringRef(Name, NameLen)));
}

enum class LLVMRustVerifierFailureAction {
  AbortProcessAction = 0,
  PrintMessageAction = 1,
  ReturnStatusAction = 2,
};

static LLVMVerifierFailureAction
fromRust(LLVMRustVerifierFailureAction Action) {
  switch (Action) {
  case LLVMRustVerifierFailureAction::AbortProcessAction:
    return LLVMAbortProcessAction;
  case LLVMRustVerifierFailureAction::PrintMessageAction:
    return LLVMPrintMessageAction;
  case LLVMRustVerifierFailureAction::ReturnStatusAction:
    return LLVMReturnStatusAction;
  }
  report_fatal_error("Invalid LLVMVerifierFailureAction value!");
}

extern "C" LLVMBool
LLVMRustVerifyFunction(LLVMValueRef Fn, LLVMRustVerifierFailureAction Action) {
  return LLVMVerifyFunction(Fn, fromRust(Action));
}

extern "C" LLVMValueRef LLVMRustGetOrInsertFunction(LLVMModuleRef M,
                                                    const char *Name,
                                                    size_t NameLen,
                                                    LLVMTypeRef FunctionTy) {
  return wrap(unwrap(M)
                  ->getOrInsertFunction(StringRef(Name, NameLen),
                                        unwrap<FunctionType>(FunctionTy))
                  .getCallee());
}

extern "C" LLVMValueRef LLVMRustGetOrInsertGlobal(LLVMModuleRef M,
                                                  const char *Name,
                                                  size_t NameLen,
                                                  LLVMTypeRef Ty) {
  Module *Mod = unwrap(M);
  auto NameRef = StringRef(Name, NameLen);

  // We don't use Module::getOrInsertGlobal because that returns a Constant*,
  // which may either be the real GlobalVariable*, or a constant bitcast of it
  // if our type doesn't match the original declaration. We always want the
  // GlobalVariable* so we can access linkage, visibility, etc.
  GlobalVariable *GV = Mod->getGlobalVariable(NameRef, true);
  if (!GV)
    GV = new GlobalVariable(*Mod, unwrap(Ty), false,
                            GlobalValue::ExternalLinkage, nullptr, NameRef);
  return wrap(GV);
}

extern "C" LLVMValueRef LLVMRustInsertPrivateGlobal(LLVMModuleRef M,
                                                    LLVMTypeRef Ty) {
  return wrap(new GlobalVariable(*unwrap(M), unwrap(Ty), false,
                                 GlobalValue::PrivateLinkage, nullptr));
}

// Must match the layout of `rustc_codegen_llvm::llvm::ffi::AttributeKind`.
enum class LLVMRustAttributeKind {
  AlwaysInline = 0,
  ByVal = 1,
  Cold = 2,
  InlineHint = 3,
  MinSize = 4,
  Naked = 5,
  NoAlias = 6,
  NoCapture = 7,
  NoInline = 8,
  NonNull = 9,
  NoRedZone = 10,
  NoReturn = 11,
  NoUnwind = 12,
  OptimizeForSize = 13,
  ReadOnly = 14,
  SExt = 15,
  StructRet = 16,
  UWTable = 17,
  ZExt = 18,
  InReg = 19,
  SanitizeThread = 20,
  SanitizeAddress = 21,
  SanitizeMemory = 22,
  NonLazyBind = 23,
  OptimizeNone = 24,
  ReadNone = 26,
  SanitizeHWAddress = 28,
  WillReturn = 29,
  StackProtectReq = 30,
  StackProtectStrong = 31,
  StackProtect = 32,
  NoUndef = 33,
  SanitizeMemTag = 34,
  NoCfCheck = 35,
  ShadowCallStack = 36,
  AllocSize = 37,
  AllocatedPointer = 38,
  AllocAlign = 39,
  SanitizeSafeStack = 40,
  FnRetThunkExtern = 41,
  Writable = 42,
  DeadOnUnwind = 43,
  DeadOnReturn = 44,
  CapturesReadOnly = 45,
};

static Attribute::AttrKind fromRust(LLVMRustAttributeKind Kind) {
  switch (Kind) {
  case LLVMRustAttributeKind::AlwaysInline:
    return Attribute::AlwaysInline;
  case LLVMRustAttributeKind::ByVal:
    return Attribute::ByVal;
  case LLVMRustAttributeKind::Cold:
    return Attribute::Cold;
  case LLVMRustAttributeKind::InlineHint:
    return Attribute::InlineHint;
  case LLVMRustAttributeKind::MinSize:
    return Attribute::MinSize;
  case LLVMRustAttributeKind::Naked:
    return Attribute::Naked;
  case LLVMRustAttributeKind::NoAlias:
    return Attribute::NoAlias;
  case LLVMRustAttributeKind::NoCapture:
#if LLVM_VERSION_GE(21, 0)
    report_fatal_error("NoCapture doesn't exist in LLVM 21");
#else
    return Attribute::NoCapture;
#endif
  case LLVMRustAttributeKind::NoCfCheck:
    return Attribute::NoCfCheck;
  case LLVMRustAttributeKind::NoInline:
    return Attribute::NoInline;
  case LLVMRustAttributeKind::NonNull:
    return Attribute::NonNull;
  case LLVMRustAttributeKind::NoRedZone:
    return Attribute::NoRedZone;
  case LLVMRustAttributeKind::NoReturn:
    return Attribute::NoReturn;
  case LLVMRustAttributeKind::NoUnwind:
    return Attribute::NoUnwind;
  case LLVMRustAttributeKind::OptimizeForSize:
    return Attribute::OptimizeForSize;
  case LLVMRustAttributeKind::ReadOnly:
    return Attribute::ReadOnly;
  case LLVMRustAttributeKind::SExt:
    return Attribute::SExt;
  case LLVMRustAttributeKind::StructRet:
    return Attribute::StructRet;
  case LLVMRustAttributeKind::UWTable:
    return Attribute::UWTable;
  case LLVMRustAttributeKind::ZExt:
    return Attribute::ZExt;
  case LLVMRustAttributeKind::InReg:
    return Attribute::InReg;
  case LLVMRustAttributeKind::SanitizeThread:
    return Attribute::SanitizeThread;
  case LLVMRustAttributeKind::SanitizeAddress:
    return Attribute::SanitizeAddress;
  case LLVMRustAttributeKind::SanitizeMemory:
    return Attribute::SanitizeMemory;
  case LLVMRustAttributeKind::NonLazyBind:
    return Attribute::NonLazyBind;
  case LLVMRustAttributeKind::OptimizeNone:
    return Attribute::OptimizeNone;
  case LLVMRustAttributeKind::ReadNone:
    return Attribute::ReadNone;
  case LLVMRustAttributeKind::SanitizeHWAddress:
    return Attribute::SanitizeHWAddress;
  case LLVMRustAttributeKind::WillReturn:
    return Attribute::WillReturn;
  case LLVMRustAttributeKind::StackProtectReq:
    return Attribute::StackProtectReq;
  case LLVMRustAttributeKind::StackProtectStrong:
    return Attribute::StackProtectStrong;
  case LLVMRustAttributeKind::StackProtect:
    return Attribute::StackProtect;
  case LLVMRustAttributeKind::NoUndef:
    return Attribute::NoUndef;
  case LLVMRustAttributeKind::SanitizeMemTag:
    return Attribute::SanitizeMemTag;
  case LLVMRustAttributeKind::ShadowCallStack:
    return Attribute::ShadowCallStack;
  case LLVMRustAttributeKind::AllocSize:
    return Attribute::AllocSize;
  case LLVMRustAttributeKind::AllocatedPointer:
    return Attribute::AllocatedPointer;
  case LLVMRustAttributeKind::AllocAlign:
    return Attribute::AllocAlign;
  case LLVMRustAttributeKind::SanitizeSafeStack:
    return Attribute::SafeStack;
  case LLVMRustAttributeKind::FnRetThunkExtern:
    return Attribute::FnRetThunkExtern;
  case LLVMRustAttributeKind::Writable:
    return Attribute::Writable;
  case LLVMRustAttributeKind::DeadOnUnwind:
    return Attribute::DeadOnUnwind;
  case LLVMRustAttributeKind::DeadOnReturn:
#if LLVM_VERSION_GE(21, 0)
    return Attribute::DeadOnReturn;
#else
    report_fatal_error("DeadOnReturn attribute requires LLVM 21 or later");
#endif
  case LLVMRustAttributeKind::CapturesReadOnly:
    report_fatal_error("Should be handled separately");
  }
  report_fatal_error("bad LLVMRustAttributeKind");
}

template <typename T>
static inline void AddAttributes(T *t, unsigned Index, LLVMAttributeRef *Attrs,
                                 size_t AttrsLen) {
  AttributeList PAL = t->getAttributes();
  auto B = AttrBuilder(t->getContext());
  for (LLVMAttributeRef Attr : ArrayRef<LLVMAttributeRef>(Attrs, AttrsLen))
    B.addAttribute(unwrap(Attr));
  AttributeList PALNew = PAL.addAttributesAtIndex(t->getContext(), Index, B);
  t->setAttributes(PALNew);
}

extern "C" bool LLVMRustHasAttributeAtIndex(LLVMValueRef Fn, unsigned Index,
                                            LLVMRustAttributeKind RustAttr) {
  Function *F = unwrap<Function>(Fn);
  return F->hasParamAttribute(Index, fromRust(RustAttr));
}

extern "C" void LLVMRustAddFunctionAttributes(LLVMValueRef Fn, unsigned Index,
                                              LLVMAttributeRef *Attrs,
                                              size_t AttrsLen) {
  Function *F = unwrap<Function>(Fn);
  AddAttributes(F, Index, Attrs, AttrsLen);
}

extern "C" void LLVMRustAddCallSiteAttributes(LLVMValueRef Instr,
                                              unsigned Index,
                                              LLVMAttributeRef *Attrs,
                                              size_t AttrsLen) {
  CallBase *Call = unwrap<CallBase>(Instr);
  AddAttributes(Call, Index, Attrs, AttrsLen);
}

extern "C" LLVMValueRef LLVMRustGetTerminator(LLVMBasicBlockRef BB) {
  Instruction *ret = unwrap(BB)->getTerminator();
  return wrap(ret);
}

extern "C" void LLVMRustEraseInstFromParent(LLVMValueRef Instr) {
  if (auto I = dyn_cast<Instruction>(unwrap<Value>(Instr))) {
    I->eraseFromParent();
  }
}

extern "C" LLVMAttributeRef
LLVMRustCreateAttrNoValue(LLVMContextRef C, LLVMRustAttributeKind RustAttr) {
#if LLVM_VERSION_GE(21, 0)
  // LLVM 21 replaced the NoCapture attribute with Captures(none).
  if (RustAttr == LLVMRustAttributeKind::NoCapture) {
    return wrap(Attribute::getWithCaptureInfo(*unwrap(C), CaptureInfo::none()));
  }
  if (RustAttr == LLVMRustAttributeKind::CapturesReadOnly) {
    return wrap(Attribute::getWithCaptureInfo(
        *unwrap(C), CaptureInfo(CaptureComponents::Address |
                                CaptureComponents::ReadProvenance)));
  }
#endif
  return wrap(Attribute::get(*unwrap(C), fromRust(RustAttr)));
}

extern "C" LLVMAttributeRef LLVMRustCreateAlignmentAttr(LLVMContextRef C,
                                                        uint64_t Bytes) {
  return wrap(Attribute::getWithAlignment(*unwrap(C), llvm::Align(Bytes)));
}

extern "C" LLVMAttributeRef LLVMRustCreateDereferenceableAttr(LLVMContextRef C,
                                                              uint64_t Bytes) {
  return wrap(Attribute::getWithDereferenceableBytes(*unwrap(C), Bytes));
}

extern "C" LLVMAttributeRef
LLVMRustCreateDereferenceableOrNullAttr(LLVMContextRef C, uint64_t Bytes) {
  return wrap(Attribute::getWithDereferenceableOrNullBytes(*unwrap(C), Bytes));
}

extern "C" LLVMAttributeRef LLVMRustCreateByValAttr(LLVMContextRef C,
                                                    LLVMTypeRef Ty) {
  return wrap(Attribute::getWithByValType(*unwrap(C), unwrap(Ty)));
}

extern "C" LLVMAttributeRef LLVMRustCreateStructRetAttr(LLVMContextRef C,
                                                        LLVMTypeRef Ty) {
  return wrap(Attribute::getWithStructRetType(*unwrap(C), unwrap(Ty)));
}

extern "C" LLVMAttributeRef LLVMRustCreateElementTypeAttr(LLVMContextRef C,
                                                          LLVMTypeRef Ty) {
  return wrap(Attribute::get(*unwrap(C), Attribute::ElementType, unwrap(Ty)));
}

extern "C" LLVMAttributeRef LLVMRustCreateUWTableAttr(LLVMContextRef C,
                                                      bool Async) {
  return wrap(Attribute::getWithUWTableKind(
      *unwrap(C), Async ? UWTableKind::Async : UWTableKind::Sync));
}

extern "C" LLVMAttributeRef
LLVMRustCreateAllocSizeAttr(LLVMContextRef C, uint32_t ElementSizeArg) {
  return wrap(Attribute::getWithAllocSizeArgs(*unwrap(C), ElementSizeArg,
                                              std::nullopt));
}

extern "C" LLVMAttributeRef
LLVMRustCreateRangeAttribute(LLVMContextRef C, unsigned NumBits,
                             const uint64_t LowerWords[],
                             const uint64_t UpperWords[]) {
  // FIXME(Zalathar): There appears to be no stable guarantee that C++
  // `AttrKind` values correspond directly to the `unsigned KindID` values
  // accepted by LLVM-C API functions, though in practice they currently do.
  return LLVMCreateConstantRangeAttribute(C, Attribute::Range, NumBits,
                                          LowerWords, UpperWords);
}

// These values **must** match ffi::AllocKindFlags.
// It _happens_ to match the LLVM values of llvm::AllocFnKind,
// but that's happenstance and we do explicit conversions before
// passing them to LLVM.
enum class LLVMRustAllocKindFlags : uint64_t {
  Unknown = 0,
  Alloc = 1,
  Realloc = 1 << 1,
  Free = 1 << 2,
  Uninitialized = 1 << 3,
  Zeroed = 1 << 4,
  Aligned = 1 << 5,
};

static LLVMRustAllocKindFlags operator&(LLVMRustAllocKindFlags A,
                                        LLVMRustAllocKindFlags B) {
  return static_cast<LLVMRustAllocKindFlags>(static_cast<uint64_t>(A) &
                                             static_cast<uint64_t>(B));
}

static bool isSet(LLVMRustAllocKindFlags F) {
  return F != LLVMRustAllocKindFlags::Unknown;
}

static llvm::AllocFnKind allocKindFromRust(LLVMRustAllocKindFlags F) {
  llvm::AllocFnKind AFK = llvm::AllocFnKind::Unknown;
  if (isSet(F & LLVMRustAllocKindFlags::Alloc)) {
    AFK |= llvm::AllocFnKind::Alloc;
  }
  if (isSet(F & LLVMRustAllocKindFlags::Realloc)) {
    AFK |= llvm::AllocFnKind::Realloc;
  }
  if (isSet(F & LLVMRustAllocKindFlags::Free)) {
    AFK |= llvm::AllocFnKind::Free;
  }
  if (isSet(F & LLVMRustAllocKindFlags::Uninitialized)) {
    AFK |= llvm::AllocFnKind::Uninitialized;
  }
  if (isSet(F & LLVMRustAllocKindFlags::Zeroed)) {
    AFK |= llvm::AllocFnKind::Zeroed;
  }
  if (isSet(F & LLVMRustAllocKindFlags::Aligned)) {
    AFK |= llvm::AllocFnKind::Aligned;
  }
  return AFK;
}

extern "C" LLVMAttributeRef LLVMRustCreateAllocKindAttr(LLVMContextRef C,
                                                        uint64_t AllocKindArg) {
  return wrap(
      Attribute::get(*unwrap(C), Attribute::AllocKind,
                     static_cast<uint64_t>(allocKindFromRust(
                         static_cast<LLVMRustAllocKindFlags>(AllocKindArg)))));
}

// Simplified representation of `MemoryEffects` across the FFI boundary.
//
// Each variant corresponds to one of the static factory methods on
// `MemoryEffects`.
enum class LLVMRustMemoryEffects {
  None,
  ReadOnly,
  InaccessibleMemOnly,
};

extern "C" LLVMAttributeRef
LLVMRustCreateMemoryEffectsAttr(LLVMContextRef C,
                                LLVMRustMemoryEffects Effects) {
  switch (Effects) {
  case LLVMRustMemoryEffects::None:
    return wrap(
        Attribute::getWithMemoryEffects(*unwrap(C), MemoryEffects::none()));
  case LLVMRustMemoryEffects::ReadOnly:
    return wrap(
        Attribute::getWithMemoryEffects(*unwrap(C), MemoryEffects::readOnly()));
  case LLVMRustMemoryEffects::InaccessibleMemOnly:
    return wrap(Attribute::getWithMemoryEffects(
        *unwrap(C), MemoryEffects::inaccessibleMemOnly()));
  default:
    report_fatal_error("bad MemoryEffects.");
  }
}

// Enable all fast-math flags, including those which will cause floating-point
// operations to return poison for some well-defined inputs. This function can
// only be used to build unsafe Rust intrinsics. That unsafety does permit
// additional optimizations, but at the time of writing, their value is not
// well-understood relative to those enabled by LLVMRustSetAlgebraicMath.
//
// https://llvm.org/docs/LangRef.html#fast-math-flags
extern "C" void LLVMRustSetFastMath(LLVMValueRef V) {
  if (auto I = dyn_cast<Instruction>(unwrap<Value>(V))) {
    I->setFast(true);
  }
}

// Enable fast-math flags which permit algebraic transformations that are not
// allowed by IEEE floating point. For example: a + (b + c) = (a + b) + c and a
// / b = a * (1 / b) Note that this does NOT enable any flags which can cause a
// floating-point operation on well-defined inputs to return poison, and
// therefore this function can be used to build safe Rust intrinsics (such as
// fadd_algebraic).
//
// https://llvm.org/docs/LangRef.html#fast-math-flags
extern "C" void LLVMRustSetAlgebraicMath(LLVMValueRef V) {
  if (auto I = dyn_cast<Instruction>(unwrap<Value>(V))) {
    I->setHasAllowReassoc(true);
    I->setHasAllowContract(true);
    I->setHasAllowReciprocal(true);
    I->setHasNoSignedZeros(true);
  }
}

// Enable the reassoc fast-math flag, allowing transformations that pretend
// floating-point addition and multiplication are associative.
//
// Note that this does NOT enable any flags which can cause a floating-point
// operation on well-defined inputs to return poison, and therefore this
// function can be used to build safe Rust intrinsics (such as fadd_algebraic).
//
// https://llvm.org/docs/LangRef.html#fast-math-flags
extern "C" void LLVMRustSetAllowReassoc(LLVMValueRef V) {
  if (auto I = dyn_cast<Instruction>(unwrap<Value>(V))) {
    I->setHasAllowReassoc(true);
  }
}

extern "C" LLVMValueRef
LLVMRustBuildAtomicLoad(LLVMBuilderRef B, LLVMTypeRef Ty, LLVMValueRef Source,
                        const char *Name, LLVMAtomicOrdering Order) {
  Value *Ptr = unwrap(Source);
  LoadInst *LI = unwrap(B)->CreateLoad(unwrap(Ty), Ptr, Name);
  LI->setAtomic(fromRust(Order));
  return wrap(LI);
}

extern "C" LLVMValueRef LLVMRustBuildAtomicStore(LLVMBuilderRef B,
                                                 LLVMValueRef V,
                                                 LLVMValueRef Target,
                                                 LLVMAtomicOrdering Order) {
  StoreInst *SI = unwrap(B)->CreateStore(unwrap(V), unwrap(Target));
  SI->setAtomic(fromRust(Order));
  return wrap(SI);
}

extern "C" uint64_t LLVMRustGetArrayNumElements(LLVMTypeRef Ty) {
  return unwrap(Ty)->getArrayNumElements();
}

extern "C" bool LLVMRustInlineAsmVerify(LLVMTypeRef Ty, char *Constraints,
                                        size_t ConstraintsLen) {
  // llvm::Error converts to true if it is an error.
  return !llvm::errorToBool(InlineAsm::verify(
      unwrap<FunctionType>(Ty), StringRef(Constraints, ConstraintsLen)));
}

template <typename DIT> DIT *unwrapDIPtr(LLVMMetadataRef Ref) {
  return (DIT *)(Ref ? unwrap<MDNode>(Ref) : nullptr);
}

#define DIDescriptor DIScope
#define DIArray DINodeArray
#define unwrapDI unwrapDIPtr

// Statically assert that `LLVMDIFlags` (C) and `DIFlags` (C++) have the same
// layout, at least for the flags we know about. This isn't guaranteed, but is
// likely to remain true, and as long as it is true it makes conversions easy.
#define ASSERT_DIFLAG_VALUE(FLAG, VALUE)                                       \
  static_assert((LLVMDI##FLAG == (VALUE)) && (DINode::DIFlags::FLAG == (VALUE)))
ASSERT_DIFLAG_VALUE(FlagZero, 0);
ASSERT_DIFLAG_VALUE(FlagPrivate, 1);
ASSERT_DIFLAG_VALUE(FlagProtected, 2);
ASSERT_DIFLAG_VALUE(FlagPublic, 3);
// Bit (1 << 1) is part of the private/protected/public values above.
ASSERT_DIFLAG_VALUE(FlagFwdDecl, 1 << 2);
ASSERT_DIFLAG_VALUE(FlagAppleBlock, 1 << 3);
ASSERT_DIFLAG_VALUE(FlagReservedBit4, 1 << 4);
ASSERT_DIFLAG_VALUE(FlagVirtual, 1 << 5);
ASSERT_DIFLAG_VALUE(FlagArtificial, 1 << 6);
ASSERT_DIFLAG_VALUE(FlagExplicit, 1 << 7);
ASSERT_DIFLAG_VALUE(FlagPrototyped, 1 << 8);
ASSERT_DIFLAG_VALUE(FlagObjcClassComplete, 1 << 9);
ASSERT_DIFLAG_VALUE(FlagObjectPointer, 1 << 10);
ASSERT_DIFLAG_VALUE(FlagVector, 1 << 11);
ASSERT_DIFLAG_VALUE(FlagStaticMember, 1 << 12);
ASSERT_DIFLAG_VALUE(FlagLValueReference, 1 << 13);
ASSERT_DIFLAG_VALUE(FlagRValueReference, 1 << 14);
// Bit (1 << 15) has been recycled, but the C API value hasn't been renamed.
static_assert((LLVMDIFlagReserved == (1 << 15)) &&
              (DINode::DIFlags::FlagExportSymbols == (1 << 15)));
ASSERT_DIFLAG_VALUE(FlagSingleInheritance, 1 << 16);
ASSERT_DIFLAG_VALUE(FlagMultipleInheritance, 2 << 16);
ASSERT_DIFLAG_VALUE(FlagVirtualInheritance, 3 << 16);
// Bit (1 << 17) is part of the inheritance values above.
ASSERT_DIFLAG_VALUE(FlagIntroducedVirtual, 1 << 18);
ASSERT_DIFLAG_VALUE(FlagBitField, 1 << 19);
ASSERT_DIFLAG_VALUE(FlagNoReturn, 1 << 20);
// Bit (1 << 21) is unused, but was `LLVMDIFlagMainSubprogram`.
ASSERT_DIFLAG_VALUE(FlagTypePassByValue, 1 << 22);
ASSERT_DIFLAG_VALUE(FlagTypePassByReference, 1 << 23);
ASSERT_DIFLAG_VALUE(FlagEnumClass, 1 << 24);
ASSERT_DIFLAG_VALUE(FlagThunk, 1 << 25);
ASSERT_DIFLAG_VALUE(FlagNonTrivial, 1 << 26);
ASSERT_DIFLAG_VALUE(FlagBigEndian, 1 << 27);
ASSERT_DIFLAG_VALUE(FlagLittleEndian, 1 << 28);
ASSERT_DIFLAG_VALUE(FlagIndirectVirtualBase, (1 << 2) | (1 << 5));
#undef ASSERT_DIFLAG_VALUE

// There are two potential ways to convert `LLVMDIFlags` to `DIFlags`:
// - Check and copy every individual bit/subvalue from input to output.
// - Statically assert that both have the same layout, and cast.
// As long as the static assertions succeed, a cast is easier and faster.
// In the (hopefully) unlikely event that the assertions do fail someday, and
// LLVM doesn't expose its own conversion function, we'll have to switch over
// to copying each bit/subvalue.
static DINode::DIFlags fromRust(LLVMDIFlags Flags) {
  // Check that all set bits are covered by the static assertions above.
  const unsigned UNKNOWN_BITS = (1 << 31) | (1 << 30) | (1 << 29) | (1 << 21);
  if (Flags & UNKNOWN_BITS) {
    report_fatal_error("bad LLVMDIFlags");
  }

  // As long as the static assertions are satisfied and no unknown bits are
  // present, we can convert from `LLVMDIFlags` to `DIFlags` with a cast.
  return static_cast<DINode::DIFlags>(Flags);
}

// These values **must** match debuginfo::DISPFlags! They also *happen*
// to match LLVM, but that isn't required as we do giant sets of
// matching below. The value shouldn't be directly passed to LLVM.
enum class LLVMRustDISPFlags : uint32_t {
  SPFlagZero = 0,
  SPFlagVirtual = 1,
  SPFlagPureVirtual = 2,
  SPFlagLocalToUnit = (1 << 2),
  SPFlagDefinition = (1 << 3),
  SPFlagOptimized = (1 << 4),
  SPFlagMainSubprogram = (1 << 5),
  // Do not add values that are not supported by the minimum LLVM
  // version we support! see llvm/include/llvm/IR/DebugInfoFlags.def
  // (In LLVM < 8, createFunction supported these as separate bool arguments.)
};

inline LLVMRustDISPFlags operator&(LLVMRustDISPFlags A, LLVMRustDISPFlags B) {
  return static_cast<LLVMRustDISPFlags>(static_cast<uint32_t>(A) &
                                        static_cast<uint32_t>(B));
}

inline LLVMRustDISPFlags operator|(LLVMRustDISPFlags A, LLVMRustDISPFlags B) {
  return static_cast<LLVMRustDISPFlags>(static_cast<uint32_t>(A) |
                                        static_cast<uint32_t>(B));
}

inline LLVMRustDISPFlags &operator|=(LLVMRustDISPFlags &A,
                                     LLVMRustDISPFlags B) {
  return A = A | B;
}

inline bool isSet(LLVMRustDISPFlags F) {
  return F != LLVMRustDISPFlags::SPFlagZero;
}

inline LLVMRustDISPFlags virtuality(LLVMRustDISPFlags F) {
  return static_cast<LLVMRustDISPFlags>(static_cast<uint32_t>(F) & 0x3);
}

static DISubprogram::DISPFlags fromRust(LLVMRustDISPFlags SPFlags) {
  DISubprogram::DISPFlags Result = DISubprogram::DISPFlags::SPFlagZero;

  switch (virtuality(SPFlags)) {
  case LLVMRustDISPFlags::SPFlagVirtual:
    Result |= DISubprogram::DISPFlags::SPFlagVirtual;
    break;
  case LLVMRustDISPFlags::SPFlagPureVirtual:
    Result |= DISubprogram::DISPFlags::SPFlagPureVirtual;
    break;
  default:
    // The rest are handled below
    break;
  }

  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagLocalToUnit)) {
    Result |= DISubprogram::DISPFlags::SPFlagLocalToUnit;
  }
  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagDefinition)) {
    Result |= DISubprogram::DISPFlags::SPFlagDefinition;
  }
  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagOptimized)) {
    Result |= DISubprogram::DISPFlags::SPFlagOptimized;
  }
  if (isSet(SPFlags & LLVMRustDISPFlags::SPFlagMainSubprogram)) {
    Result |= DISubprogram::DISPFlags::SPFlagMainSubprogram;
  }

  return Result;
}

enum class LLVMRustDebugEmissionKind {
  NoDebug,
  FullDebug,
  LineTablesOnly,
  DebugDirectivesOnly,
};

static DICompileUnit::DebugEmissionKind
fromRust(LLVMRustDebugEmissionKind Kind) {
  switch (Kind) {
  case LLVMRustDebugEmissionKind::NoDebug:
    return DICompileUnit::DebugEmissionKind::NoDebug;
  case LLVMRustDebugEmissionKind::FullDebug:
    return DICompileUnit::DebugEmissionKind::FullDebug;
  case LLVMRustDebugEmissionKind::LineTablesOnly:
    return DICompileUnit::DebugEmissionKind::LineTablesOnly;
  case LLVMRustDebugEmissionKind::DebugDirectivesOnly:
    return DICompileUnit::DebugEmissionKind::DebugDirectivesOnly;
  default:
    report_fatal_error("bad DebugEmissionKind.");
  }
}

enum class LLVMRustDebugNameTableKind {
  Default,
  GNU,
  None,
};

static DICompileUnit::DebugNameTableKind
fromRust(LLVMRustDebugNameTableKind Kind) {
  switch (Kind) {
  case LLVMRustDebugNameTableKind::Default:
    return DICompileUnit::DebugNameTableKind::Default;
  case LLVMRustDebugNameTableKind::GNU:
    return DICompileUnit::DebugNameTableKind::GNU;
  case LLVMRustDebugNameTableKind::None:
    return DICompileUnit::DebugNameTableKind::None;
  default:
    report_fatal_error("bad DebugNameTableKind.");
  }
}

enum class LLVMRustChecksumKind {
  None,
  MD5,
  SHA1,
  SHA256,
};

static std::optional<DIFile::ChecksumKind> fromRust(LLVMRustChecksumKind Kind) {
  switch (Kind) {
  case LLVMRustChecksumKind::None:
    return std::nullopt;
  case LLVMRustChecksumKind::MD5:
    return DIFile::ChecksumKind::CSK_MD5;
  case LLVMRustChecksumKind::SHA1:
    return DIFile::ChecksumKind::CSK_SHA1;
  case LLVMRustChecksumKind::SHA256:
    return DIFile::ChecksumKind::CSK_SHA256;
  default:
    report_fatal_error("bad ChecksumKind.");
  }
}

extern "C" uint32_t LLVMRustDebugMetadataVersion() {
  return DEBUG_METADATA_VERSION;
}

extern "C" uint32_t LLVMRustVersionPatch() { return LLVM_VERSION_PATCH; }

extern "C" uint32_t LLVMRustVersionMinor() { return LLVM_VERSION_MINOR; }

extern "C" uint32_t LLVMRustVersionMajor() { return LLVM_VERSION_MAJOR; }

// FFI equivalent of LLVM's `llvm::Module::ModFlagBehavior`.
// Must match the layout of
// `rustc_codegen_llvm::llvm::ffi::ModuleFlagMergeBehavior`.
//
// There is a stable LLVM-C version of this enum (`LLVMModuleFlagBehavior`),
// but as of LLVM 19 it does not support all of the enum values in the unstable
// C++ API.
enum class LLVMRustModuleFlagMergeBehavior {
  Error = 1,
  Warning = 2,
  Require = 3,
  Override = 4,
  Append = 5,
  AppendUnique = 6,
  Max = 7,
  Min = 8,
};

static Module::ModFlagBehavior
fromRust(LLVMRustModuleFlagMergeBehavior Behavior) {
  switch (Behavior) {
  case LLVMRustModuleFlagMergeBehavior::Error:
    return Module::ModFlagBehavior::Error;
  case LLVMRustModuleFlagMergeBehavior::Warning:
    return Module::ModFlagBehavior::Warning;
  case LLVMRustModuleFlagMergeBehavior::Require:
    return Module::ModFlagBehavior::Require;
  case LLVMRustModuleFlagMergeBehavior::Override:
    return Module::ModFlagBehavior::Override;
  case LLVMRustModuleFlagMergeBehavior::Append:
    return Module::ModFlagBehavior::Append;
  case LLVMRustModuleFlagMergeBehavior::AppendUnique:
    return Module::ModFlagBehavior::AppendUnique;
  case LLVMRustModuleFlagMergeBehavior::Max:
    return Module::ModFlagBehavior::Max;
  case LLVMRustModuleFlagMergeBehavior::Min:
    return Module::ModFlagBehavior::Min;
  }
  report_fatal_error("bad LLVMRustModuleFlagMergeBehavior");
}

extern "C" void
LLVMRustAddModuleFlagU32(LLVMModuleRef M,
                         LLVMRustModuleFlagMergeBehavior MergeBehavior,
                         const char *Name, size_t NameLen, uint32_t Value) {
  unwrap(M)->addModuleFlag(fromRust(MergeBehavior), StringRef(Name, NameLen),
                           Value);
}

extern "C" void LLVMRustAddModuleFlagString(
    LLVMModuleRef M, LLVMRustModuleFlagMergeBehavior MergeBehavior,
    const char *Name, size_t NameLen, const char *Value, size_t ValueLen) {
  unwrap(M)->addModuleFlag(
      fromRust(MergeBehavior), StringRef(Name, NameLen),
      MDString::get(unwrap(M)->getContext(), StringRef(Value, ValueLen)));
}

extern "C" LLVMValueRef LLVMRustGetLastInstruction(LLVMBasicBlockRef BB) {
  auto Point = unwrap(BB)->rbegin();
  if (Point != unwrap(BB)->rend())
    return wrap(&*Point);
  return nullptr;
}

extern "C" void LLVMRustEraseInstUntilInclusive(LLVMBasicBlockRef bb,
                                                LLVMValueRef I) {
  auto &BB = *unwrap(bb);
  auto &Inst = *unwrap<Instruction>(I);
  auto It = BB.begin();
  while (&*It != &Inst)
    ++It;
  // Make sure we found the Instruction.
  assert(It != BB.end());
  // Delete in rev order to ensure no dangling references.
  while (It != BB.begin()) {
    auto Prev = std::prev(It);
    It->eraseFromParent();
    It = Prev;
  }
  It->eraseFromParent();
}

extern "C" bool LLVMRustHasMetadata(LLVMValueRef inst, unsigned kindID) {
  if (auto *I = dyn_cast<Instruction>(unwrap<Value>(inst))) {
    return I->hasMetadata(kindID);
  }
  return false;
}

extern "C" LLVMMetadataRef LLVMRustDIGetInstMetadata(LLVMValueRef x) {
  if (auto *I = dyn_cast<Instruction>(unwrap<Value>(x))) {
    auto *MD = I->getDebugLoc().getAsMDNode();
    return wrap(MD);
  }
  return nullptr;
}

extern "C" void
LLVMRustRemoveEnumAttributeAtIndex(LLVMValueRef F, size_t index,
                                   LLVMRustAttributeKind RustAttr) {
  LLVMRemoveEnumAttributeAtIndex(F, index, fromRust(RustAttr));
}

extern "C" bool LLVMRustHasFnAttribute(LLVMValueRef F, const char *Name,
                                       size_t NameLen) {
  if (auto *Fn = dyn_cast<Function>(unwrap<Value>(F))) {
    return Fn->hasFnAttribute(StringRef(Name, NameLen));
  }
  return false;
}

extern "C" void LLVMRustRemoveFnAttribute(LLVMValueRef Fn, const char *Name,
                                          size_t NameLen) {
  if (auto *F = dyn_cast<Function>(unwrap<Value>(Fn))) {
    F->removeFnAttr(StringRef(Name, NameLen));
  }
}

extern "C" void LLVMRustGlobalAddMetadata(LLVMValueRef Global, unsigned Kind,
                                          LLVMMetadataRef MD) {
  unwrap<GlobalObject>(Global)->addMetadata(Kind, *unwrap<MDNode>(MD));
}

extern "C" LLVMDIBuilderRef LLVMRustDIBuilderCreate(LLVMModuleRef M) {
  return wrap(new DIBuilder(*unwrap(M)));
}

extern "C" void LLVMRustDIBuilderDispose(LLVMDIBuilderRef Builder) {
  delete unwrap(Builder);
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateCompileUnit(
    LLVMDIBuilderRef Builder, unsigned Lang, LLVMMetadataRef FileRef,
    const char *Producer, size_t ProducerLen, bool isOptimized,
    const char *Flags, unsigned RuntimeVer, const char *SplitName,
    size_t SplitNameLen, LLVMRustDebugEmissionKind Kind, uint64_t DWOId,
    bool SplitDebugInlining, LLVMRustDebugNameTableKind TableKind) {
  auto *File = unwrapDI<DIFile>(FileRef);

  return wrap(unwrap(Builder)->createCompileUnit(
      Lang, File, StringRef(Producer, ProducerLen), isOptimized, Flags,
      RuntimeVer, StringRef(SplitName, SplitNameLen), fromRust(Kind), DWOId,
      SplitDebugInlining, false, fromRust(TableKind)));
}

extern "C" LLVMMetadataRef
LLVMRustDIBuilderCreateFile(LLVMDIBuilderRef Builder, const char *Filename,
                            size_t FilenameLen, const char *Directory,
                            size_t DirectoryLen, LLVMRustChecksumKind CSKind,
                            const char *Checksum, size_t ChecksumLen,
                            const char *Source, size_t SourceLen) {

  std::optional<DIFile::ChecksumKind> llvmCSKind = fromRust(CSKind);
  std::optional<DIFile::ChecksumInfo<StringRef>> CSInfo{};
  if (llvmCSKind)
    CSInfo.emplace(*llvmCSKind, StringRef{Checksum, ChecksumLen});
  std::optional<StringRef> oSource{};
  if (Source)
    oSource = StringRef(Source, SourceLen);
  return wrap(unwrap(Builder)->createFile(StringRef(Filename, FilenameLen),
                                          StringRef(Directory, DirectoryLen),
                                          CSInfo, oSource));
}

extern "C" LLVMMetadataRef
LLVMRustDIBuilderCreateSubroutineType(LLVMDIBuilderRef Builder,
                                      LLVMMetadataRef ParameterTypes) {
  return wrap(unwrap(Builder)->createSubroutineType(
      DITypeRefArray(unwrap<MDTuple>(ParameterTypes))));
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateFunction(
    LLVMDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
    size_t NameLen, const char *LinkageName, size_t LinkageNameLen,
    LLVMMetadataRef File, unsigned LineNo, LLVMMetadataRef Ty,
    unsigned ScopeLine, LLVMDIFlags Flags, LLVMRustDISPFlags SPFlags,
    LLVMValueRef MaybeFn, LLVMMetadataRef TParam, LLVMMetadataRef Decl) {
  DITemplateParameterArray TParams =
      DITemplateParameterArray(unwrap<MDTuple>(TParam));
  DISubprogram::DISPFlags llvmSPFlags = fromRust(SPFlags);
  DINode::DIFlags llvmFlags = fromRust(Flags);
  DISubprogram *Sub = unwrap(Builder)->createFunction(
      unwrapDI<DIScope>(Scope), StringRef(Name, NameLen),
      StringRef(LinkageName, LinkageNameLen), unwrapDI<DIFile>(File), LineNo,
      unwrapDI<DISubroutineType>(Ty), ScopeLine, llvmFlags, llvmSPFlags,
      TParams, unwrapDIPtr<DISubprogram>(Decl));
  if (MaybeFn)
    unwrap<Function>(MaybeFn)->setSubprogram(Sub);
  return wrap(Sub);
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateMethod(
    LLVMDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
    size_t NameLen, const char *LinkageName, size_t LinkageNameLen,
    LLVMMetadataRef File, unsigned LineNo, LLVMMetadataRef Ty,
    LLVMDIFlags Flags, LLVMRustDISPFlags SPFlags, LLVMMetadataRef TParam) {
  DITemplateParameterArray TParams =
      DITemplateParameterArray(unwrap<MDTuple>(TParam));
  DISubprogram::DISPFlags llvmSPFlags = fromRust(SPFlags);
  DINode::DIFlags llvmFlags = fromRust(Flags);
  DISubprogram *Sub = unwrap(Builder)->createMethod(
      unwrapDI<DIScope>(Scope), StringRef(Name, NameLen),
      StringRef(LinkageName, LinkageNameLen), unwrapDI<DIFile>(File), LineNo,
      unwrapDI<DISubroutineType>(Ty), 0, 0,
      nullptr, // VTable params aren't used
      llvmFlags, llvmSPFlags, TParams);
  return wrap(Sub);
}

extern "C" LLVMMetadataRef
LLVMRustDIBuilderCreateBasicType(LLVMDIBuilderRef Builder, const char *Name,
                                 size_t NameLen, uint64_t SizeInBits,
                                 unsigned Encoding) {
  return wrap(unwrap(Builder)->createBasicType(StringRef(Name, NameLen),
                                               SizeInBits, Encoding));
}

extern "C" LLVMMetadataRef
LLVMRustDIBuilderCreateTypedef(LLVMDIBuilderRef Builder, LLVMMetadataRef Type,
                               const char *Name, size_t NameLen,
                               LLVMMetadataRef File, unsigned LineNo,
                               LLVMMetadataRef Scope) {
  return wrap(unwrap(Builder)->createTypedef(
      unwrap<DIType>(Type), StringRef(Name, NameLen), unwrap<DIFile>(File),
      LineNo, unwrapDIPtr<DIScope>(Scope)));
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreatePointerType(
    LLVMDIBuilderRef Builder, LLVMMetadataRef PointeeTy, uint64_t SizeInBits,
    uint32_t AlignInBits, unsigned AddressSpace, const char *Name,
    size_t NameLen) {
  return wrap(unwrap(Builder)->createPointerType(
      unwrapDI<DIType>(PointeeTy), SizeInBits, AlignInBits, AddressSpace,
      StringRef(Name, NameLen)));
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateStructType(
    LLVMDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
    size_t NameLen, LLVMMetadataRef File, unsigned LineNumber,
    uint64_t SizeInBits, uint32_t AlignInBits, LLVMDIFlags Flags,
    LLVMMetadataRef DerivedFrom, LLVMMetadataRef Elements, unsigned RunTimeLang,
    LLVMMetadataRef VTableHolder, const char *UniqueId, size_t UniqueIdLen) {
  return wrap(unwrap(Builder)->createStructType(
      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
      unwrapDI<DIFile>(File), LineNumber, SizeInBits, AlignInBits,
      fromRust(Flags), unwrapDI<DIType>(DerivedFrom),
      DINodeArray(unwrapDI<MDTuple>(Elements)), RunTimeLang,
      unwrapDI<DIType>(VTableHolder), StringRef(UniqueId, UniqueIdLen)));
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateVariantPart(
    LLVMDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
    size_t NameLen, LLVMMetadataRef File, unsigned LineNumber,
    uint64_t SizeInBits, uint32_t AlignInBits, LLVMDIFlags Flags,
    LLVMMetadataRef Discriminator, LLVMMetadataRef Elements,
    const char *UniqueId, size_t UniqueIdLen) {
  return wrap(unwrap(Builder)->createVariantPart(
      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
      unwrapDI<DIFile>(File), LineNumber, SizeInBits, AlignInBits,
      fromRust(Flags), unwrapDI<DIDerivedType>(Discriminator),
      DINodeArray(unwrapDI<MDTuple>(Elements)),
      StringRef(UniqueId, UniqueIdLen)));
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateMemberType(
    LLVMDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
    size_t NameLen, LLVMMetadataRef File, unsigned LineNo, uint64_t SizeInBits,
    uint32_t AlignInBits, uint64_t OffsetInBits, LLVMDIFlags Flags,
    LLVMMetadataRef Ty) {
  return wrap(unwrap(Builder)->createMemberType(
      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
      unwrapDI<DIFile>(File), LineNo, SizeInBits, AlignInBits, OffsetInBits,
      fromRust(Flags), unwrapDI<DIType>(Ty)));
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateVariantMemberType(
    LLVMDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
    size_t NameLen, LLVMMetadataRef File, unsigned LineNo, uint64_t SizeInBits,
    uint32_t AlignInBits, uint64_t OffsetInBits, LLVMValueRef Discriminant,
    LLVMDIFlags Flags, LLVMMetadataRef Ty) {
  llvm::ConstantInt *D = nullptr;
  if (Discriminant) {
    D = unwrap<llvm::ConstantInt>(Discriminant);
  }
  return wrap(unwrap(Builder)->createVariantMemberType(
      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
      unwrapDI<DIFile>(File), LineNo, SizeInBits, AlignInBits, OffsetInBits, D,
      fromRust(Flags), unwrapDI<DIType>(Ty)));
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateStaticMemberType(
    LLVMDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
    size_t NameLen, LLVMMetadataRef File, unsigned LineNo, LLVMMetadataRef Ty,
    LLVMDIFlags Flags, LLVMValueRef val, uint32_t AlignInBits) {
  return wrap(unwrap(Builder)->createStaticMemberType(
      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
      unwrapDI<DIFile>(File), LineNo, unwrapDI<DIType>(Ty), fromRust(Flags),
      unwrap<llvm::ConstantInt>(val), llvm::dwarf::DW_TAG_member, AlignInBits));
}

extern "C" LLVMMetadataRef
LLVMRustDIBuilderCreateQualifiedType(LLVMDIBuilderRef Builder, unsigned Tag,
                                     LLVMMetadataRef Type) {
  return wrap(
      unwrap(Builder)->createQualifiedType(Tag, unwrapDI<DIType>(Type)));
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateStaticVariable(
    LLVMDIBuilderRef Builder, LLVMMetadataRef Context, const char *Name,
    size_t NameLen, const char *LinkageName, size_t LinkageNameLen,
    LLVMMetadataRef File, unsigned LineNo, LLVMMetadataRef Ty,
    bool IsLocalToUnit, LLVMValueRef V, LLVMMetadataRef Decl = nullptr,
    uint32_t AlignInBits = 0) {
  llvm::GlobalVariable *InitVal = cast<llvm::GlobalVariable>(unwrap(V));

  llvm::DIExpression *InitExpr = nullptr;
  if (llvm::ConstantInt *IntVal = llvm::dyn_cast<llvm::ConstantInt>(InitVal)) {
    InitExpr = unwrap(Builder)->createConstantValueExpression(
        IntVal->getValue().getSExtValue());
  } else if (llvm::ConstantFP *FPVal =
                 llvm::dyn_cast<llvm::ConstantFP>(InitVal)) {
    InitExpr = unwrap(Builder)->createConstantValueExpression(
        FPVal->getValueAPF().bitcastToAPInt().getZExtValue());
  }

  llvm::DIGlobalVariableExpression *VarExpr =
      unwrap(Builder)->createGlobalVariableExpression(
          unwrapDI<DIDescriptor>(Context), StringRef(Name, NameLen),
          StringRef(LinkageName, LinkageNameLen), unwrapDI<DIFile>(File),
          LineNo, unwrapDI<DIType>(Ty), IsLocalToUnit,
          /* isDefined */ true, InitExpr, unwrapDIPtr<MDNode>(Decl),
          /* templateParams */ nullptr, AlignInBits);

  InitVal->setMetadata("dbg", VarExpr);

  return wrap(VarExpr);
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateVariable(
    LLVMDIBuilderRef Builder, unsigned Tag, LLVMMetadataRef Scope,
    const char *Name, size_t NameLen, LLVMMetadataRef File, unsigned LineNo,
    LLVMMetadataRef Ty, bool AlwaysPreserve, LLVMDIFlags Flags, unsigned ArgNo,
    uint32_t AlignInBits) {
  if (Tag == 0x100) { // DW_TAG_auto_variable
    return wrap(unwrap(Builder)->createAutoVariable(
        unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
        unwrapDI<DIFile>(File), LineNo, unwrapDI<DIType>(Ty), AlwaysPreserve,
        fromRust(Flags), AlignInBits));
  } else {
    return wrap(unwrap(Builder)->createParameterVariable(
        unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen), ArgNo,
        unwrapDI<DIFile>(File), LineNo, unwrapDI<DIType>(Ty), AlwaysPreserve,
        fromRust(Flags)));
  }
}

extern "C" LLVMMetadataRef
LLVMRustDIBuilderCreateArrayType(LLVMDIBuilderRef Builder, uint64_t Size,
                                 uint32_t AlignInBits, LLVMMetadataRef Ty,
                                 LLVMMetadataRef Subscripts) {
  return wrap(unwrap(Builder)->createArrayType(
      Size, AlignInBits, unwrapDI<DIType>(Ty),
      DINodeArray(unwrapDI<MDTuple>(Subscripts))));
}

extern "C" LLVMMetadataRef
LLVMRustDIBuilderGetOrCreateSubrange(LLVMDIBuilderRef Builder, int64_t Lo,
                                     int64_t Count) {
  return wrap(unwrap(Builder)->getOrCreateSubrange(Lo, Count));
}

extern "C" LLVMMetadataRef
LLVMRustDIBuilderGetOrCreateArray(LLVMDIBuilderRef Builder,
                                  LLVMMetadataRef *Ptr, unsigned Count) {
  Metadata **DataValue = unwrap(Ptr);
  return wrap(unwrap(Builder)
                  ->getOrCreateArray(ArrayRef<Metadata *>(DataValue, Count))
                  .get());
}

extern "C" void
LLVMRustDIBuilderInsertDeclareAtEnd(LLVMDIBuilderRef Builder, LLVMValueRef V,
                                    LLVMMetadataRef VarInfo, uint64_t *AddrOps,
                                    unsigned AddrOpsCount, LLVMMetadataRef DL,
                                    LLVMBasicBlockRef InsertAtEnd) {
  unwrap(Builder)->insertDeclare(
      unwrap(V), unwrap<DILocalVariable>(VarInfo),
      unwrap(Builder)->createExpression(
          llvm::ArrayRef<uint64_t>(AddrOps, AddrOpsCount)),
      DebugLoc(cast<MDNode>(unwrap(DL))), unwrap(InsertAtEnd));
}

extern "C" LLVMMetadataRef
LLVMRustDIBuilderCreateEnumerator(LLVMDIBuilderRef Builder, const char *Name,
                                  size_t NameLen, const uint64_t Value[2],
                                  unsigned SizeInBits, bool IsUnsigned) {
  return wrap(unwrap(Builder)->createEnumerator(
      StringRef(Name, NameLen),
      APSInt(APInt(SizeInBits, ArrayRef<uint64_t>(Value, 2)), IsUnsigned)));
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateEnumerationType(
    LLVMDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
    size_t NameLen, LLVMMetadataRef File, unsigned LineNumber,
    uint64_t SizeInBits, uint32_t AlignInBits, LLVMMetadataRef Elements,
    LLVMMetadataRef ClassTy, bool IsScoped) {
  return wrap(unwrap(Builder)->createEnumerationType(
      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
      unwrapDI<DIFile>(File), LineNumber, SizeInBits, AlignInBits,
      DINodeArray(unwrapDI<MDTuple>(Elements)), unwrapDI<DIType>(ClassTy),
      /* RunTimeLang */ 0, "", IsScoped));
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateUnionType(
    LLVMDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
    size_t NameLen, LLVMMetadataRef File, unsigned LineNumber,
    uint64_t SizeInBits, uint32_t AlignInBits, LLVMDIFlags Flags,
    LLVMMetadataRef Elements, unsigned RunTimeLang, const char *UniqueId,
    size_t UniqueIdLen) {
  return wrap(unwrap(Builder)->createUnionType(
      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
      unwrapDI<DIFile>(File), LineNumber, SizeInBits, AlignInBits,
      fromRust(Flags), DINodeArray(unwrapDI<MDTuple>(Elements)), RunTimeLang,
      StringRef(UniqueId, UniqueIdLen)));
}

extern "C" LLVMMetadataRef LLVMRustDIBuilderCreateTemplateTypeParameter(
    LLVMDIBuilderRef Builder, LLVMMetadataRef Scope, const char *Name,
    size_t NameLen, LLVMMetadataRef Ty) {
  bool IsDefault = false; // FIXME: should we ever set this true?
  return wrap(unwrap(Builder)->createTemplateTypeParameter(
      unwrapDI<DIDescriptor>(Scope), StringRef(Name, NameLen),
      unwrapDI<DIType>(Ty), IsDefault));
}

extern "C" void LLVMRustDICompositeTypeReplaceArrays(
    LLVMDIBuilderRef Builder, LLVMMetadataRef CompositeTy,
    LLVMMetadataRef Elements, LLVMMetadataRef Params) {
  DICompositeType *Tmp = unwrapDI<DICompositeType>(CompositeTy);
  unwrap(Builder)->replaceArrays(Tmp, DINodeArray(unwrap<MDTuple>(Elements)),
                                 DINodeArray(unwrap<MDTuple>(Params)));
}

extern "C" LLVMMetadataRef
LLVMRustDILocationCloneWithBaseDiscriminator(LLVMMetadataRef Location,
                                             unsigned BD) {
  DILocation *Loc = unwrapDIPtr<DILocation>(Location);
  auto NewLoc = Loc->cloneWithBaseDiscriminator(BD);
  return wrap(NewLoc.has_value() ? NewLoc.value() : nullptr);
}

extern "C" void LLVMRustWriteTypeToString(LLVMTypeRef Ty, RustStringRef Str) {
  auto OS = RawRustStringOstream(Str);
  unwrap<llvm::Type>(Ty)->print(OS);
}

extern "C" void LLVMRustWriteValueToString(LLVMValueRef V, RustStringRef Str) {
  auto OS = RawRustStringOstream(Str);
  if (!V) {
    OS << "(null)";
  } else {
    OS << "(";
    unwrap<llvm::Value>(V)->getType()->print(OS);
    OS << ":";
    unwrap<llvm::Value>(V)->print(OS);
    OS << ")";
  }
}

DEFINE_SIMPLE_CONVERSION_FUNCTIONS(Twine, LLVMTwineRef)

extern "C" void LLVMRustWriteTwineToString(LLVMTwineRef T, RustStringRef Str) {
  auto OS = RawRustStringOstream(Str);
  unwrap(T)->print(OS);
}

extern "C" void LLVMRustUnpackOptimizationDiagnostic(
    LLVMDiagnosticInfoRef DI, RustStringRef PassNameOut,
    LLVMValueRef *FunctionOut, unsigned *Line, unsigned *Column,
    RustStringRef FilenameOut, RustStringRef MessageOut) {
  // Undefined to call this not on an optimization diagnostic!
  llvm::DiagnosticInfoOptimizationBase *Opt =
      static_cast<llvm::DiagnosticInfoOptimizationBase *>(unwrap(DI));

  auto PassNameOS = RawRustStringOstream(PassNameOut);
  PassNameOS << Opt->getPassName();
  *FunctionOut = wrap(&Opt->getFunction());

  auto FilenameOS = RawRustStringOstream(FilenameOut);
  DiagnosticLocation loc = Opt->getLocation();
  if (loc.isValid()) {
    *Line = loc.getLine();
    *Column = loc.getColumn();
    FilenameOS << loc.getAbsolutePath();
  }

  auto MessageOS = RawRustStringOstream(MessageOut);
  MessageOS << Opt->getMsg();
}

enum class LLVMRustDiagnosticLevel {
  Error,
  Warning,
  Note,
  Remark,
};

extern "C" void LLVMRustUnpackInlineAsmDiagnostic(
    LLVMDiagnosticInfoRef DI, LLVMRustDiagnosticLevel *LevelOut,
    uint64_t *CookieOut, LLVMTwineRef *MessageOut) {
  // Undefined to call this not on an inline assembly diagnostic!
  llvm::DiagnosticInfoInlineAsm *IA =
      static_cast<llvm::DiagnosticInfoInlineAsm *>(unwrap(DI));

  *CookieOut = IA->getLocCookie();
  *MessageOut = wrap(&IA->getMsgStr());

  switch (IA->getSeverity()) {
  case DS_Error:
    *LevelOut = LLVMRustDiagnosticLevel::Error;
    break;
  case DS_Warning:
    *LevelOut = LLVMRustDiagnosticLevel::Warning;
    break;
  case DS_Note:
    *LevelOut = LLVMRustDiagnosticLevel::Note;
    break;
  case DS_Remark:
    *LevelOut = LLVMRustDiagnosticLevel::Remark;
    break;
  default:
    report_fatal_error("Invalid LLVMRustDiagnosticLevel value!");
  }
}

extern "C" void LLVMRustWriteDiagnosticInfoToString(LLVMDiagnosticInfoRef DI,
                                                    RustStringRef Str) {
  auto OS = RawRustStringOstream(Str);
  auto DP = DiagnosticPrinterRawOStream(OS);
  unwrap(DI)->print(DP);
}

enum class LLVMRustDiagnosticKind {
  Other,
  InlineAsm,
  StackSize,
  DebugMetadataVersion,
  SampleProfile,
  OptimizationRemark,
  OptimizationRemarkMissed,
  OptimizationRemarkAnalysis,
  OptimizationRemarkAnalysisFPCommute,
  OptimizationRemarkAnalysisAliasing,
  OptimizationRemarkOther,
  OptimizationFailure,
  PGOProfile,
  Linker,
  Unsupported,
  SrcMgr,
};

static LLVMRustDiagnosticKind toRust(DiagnosticKind Kind) {
  switch (Kind) {
  case DK_InlineAsm:
    return LLVMRustDiagnosticKind::InlineAsm;
  case DK_StackSize:
    return LLVMRustDiagnosticKind::StackSize;
  case DK_DebugMetadataVersion:
    return LLVMRustDiagnosticKind::DebugMetadataVersion;
  case DK_SampleProfile:
    return LLVMRustDiagnosticKind::SampleProfile;
  case DK_OptimizationRemark:
  case DK_MachineOptimizationRemark:
    return LLVMRustDiagnosticKind::OptimizationRemark;
  case DK_OptimizationRemarkMissed:
  case DK_MachineOptimizationRemarkMissed:
    return LLVMRustDiagnosticKind::OptimizationRemarkMissed;
  case DK_OptimizationRemarkAnalysis:
  case DK_MachineOptimizationRemarkAnalysis:
    return LLVMRustDiagnosticKind::OptimizationRemarkAnalysis;
  case DK_OptimizationRemarkAnalysisFPCommute:
    return LLVMRustDiagnosticKind::OptimizationRemarkAnalysisFPCommute;
  case DK_OptimizationRemarkAnalysisAliasing:
    return LLVMRustDiagnosticKind::OptimizationRemarkAnalysisAliasing;
  case DK_PGOProfile:
    return LLVMRustDiagnosticKind::PGOProfile;
  case DK_Linker:
    return LLVMRustDiagnosticKind::Linker;
  case DK_Unsupported:
    return LLVMRustDiagnosticKind::Unsupported;
  case DK_SrcMgr:
    return LLVMRustDiagnosticKind::SrcMgr;
  default:
    return (Kind >= DK_FirstRemark && Kind <= DK_LastRemark)
               ? LLVMRustDiagnosticKind::OptimizationRemarkOther
               : LLVMRustDiagnosticKind::Other;
  }
}

extern "C" LLVMRustDiagnosticKind
LLVMRustGetDiagInfoKind(LLVMDiagnosticInfoRef DI) {
  return toRust((DiagnosticKind)unwrap(DI)->getKind());
}

DEFINE_SIMPLE_CONVERSION_FUNCTIONS(SMDiagnostic, LLVMSMDiagnosticRef)

extern "C" LLVMSMDiagnosticRef LLVMRustGetSMDiagnostic(LLVMDiagnosticInfoRef DI,
                                                       uint64_t *Cookie) {
  llvm::DiagnosticInfoSrcMgr *SM =
      static_cast<llvm::DiagnosticInfoSrcMgr *>(unwrap(DI));
  *Cookie = SM->getLocCookie();
  return wrap(&SM->getSMDiag());
}

extern "C" bool
LLVMRustUnpackSMDiagnostic(LLVMSMDiagnosticRef DRef, RustStringRef MessageOut,
                           RustStringRef BufferOut,
                           LLVMRustDiagnosticLevel *LevelOut, unsigned *LocOut,
                           unsigned *RangesOut, size_t *NumRanges) {
  SMDiagnostic &D = *unwrap(DRef);
  auto MessageOS = RawRustStringOstream(MessageOut);
  MessageOS << D.getMessage();

  switch (D.getKind()) {
  case SourceMgr::DK_Error:
    *LevelOut = LLVMRustDiagnosticLevel::Error;
    break;
  case SourceMgr::DK_Warning:
    *LevelOut = LLVMRustDiagnosticLevel::Warning;
    break;
  case SourceMgr::DK_Note:
    *LevelOut = LLVMRustDiagnosticLevel::Note;
    break;
  case SourceMgr::DK_Remark:
    *LevelOut = LLVMRustDiagnosticLevel::Remark;
    break;
  default:
    report_fatal_error("Invalid LLVMRustDiagnosticLevel value!");
  }

  if (D.getLoc() == SMLoc())
    return false;

  const SourceMgr &LSM = *D.getSourceMgr();
  const MemoryBuffer *LBuf =
      LSM.getMemoryBuffer(LSM.FindBufferContainingLoc(D.getLoc()));
  auto BufferOS = RawRustStringOstream(BufferOut);
  BufferOS << LBuf->getBuffer();

  *LocOut = D.getLoc().getPointer() - LBuf->getBufferStart();

  *NumRanges = std::min(*NumRanges, D.getRanges().size());
  size_t LineStart = *LocOut - (size_t)D.getColumnNo();
  for (size_t i = 0; i < *NumRanges; i++) {
    RangesOut[i * 2] = LineStart + D.getRanges()[i].first;
    RangesOut[i * 2 + 1] = LineStart + D.getRanges()[i].second;
  }

  return true;
}

extern "C" LLVMValueRef LLVMRustBuildMemCpy(LLVMBuilderRef B, LLVMValueRef Dst,
                                            unsigned DstAlign, LLVMValueRef Src,
                                            unsigned SrcAlign,
                                            LLVMValueRef Size,
                                            bool IsVolatile) {
  return wrap(unwrap(B)->CreateMemCpy(unwrap(Dst), MaybeAlign(DstAlign),
                                      unwrap(Src), MaybeAlign(SrcAlign),
                                      unwrap(Size), IsVolatile));
}

extern "C" LLVMValueRef
LLVMRustBuildMemMove(LLVMBuilderRef B, LLVMValueRef Dst, unsigned DstAlign,
                     LLVMValueRef Src, unsigned SrcAlign, LLVMValueRef Size,
                     bool IsVolatile) {
  return wrap(unwrap(B)->CreateMemMove(unwrap(Dst), MaybeAlign(DstAlign),
                                       unwrap(Src), MaybeAlign(SrcAlign),
                                       unwrap(Size), IsVolatile));
}

extern "C" LLVMValueRef LLVMRustBuildMemSet(LLVMBuilderRef B, LLVMValueRef Dst,
                                            unsigned DstAlign, LLVMValueRef Val,
                                            LLVMValueRef Size,
                                            bool IsVolatile) {
  return wrap(unwrap(B)->CreateMemSet(unwrap(Dst), unwrap(Val), unwrap(Size),
                                      MaybeAlign(DstAlign), IsVolatile));
}

extern "C" void LLVMRustPositionBuilderPastAllocas(LLVMBuilderRef B,
                                                   LLVMValueRef Fn) {
  Function *F = unwrap<Function>(Fn);
  unwrap(B)->SetInsertPointPastAllocas(F);
}
extern "C" void LLVMRustPositionBuilderAtStart(LLVMBuilderRef B,
                                               LLVMBasicBlockRef BB) {
  auto Point = unwrap(BB)->getFirstInsertionPt();
  unwrap(B)->SetInsertPoint(unwrap(BB), Point);
}

extern "C" void LLVMRustPositionBefore(LLVMBuilderRef B, LLVMValueRef Instr) {
  if (auto I = dyn_cast<Instruction>(unwrap<Value>(Instr))) {
    unwrap(B)->SetInsertPoint(I);
  }
}

extern "C" void LLVMRustPositionAfter(LLVMBuilderRef B, LLVMValueRef Instr) {
  if (auto I = dyn_cast<Instruction>(unwrap<Value>(Instr))) {
    auto J = I->getNextNode();
    unwrap(B)->SetInsertPoint(J);
  }
}

extern "C" LLVMValueRef
LLVMRustGetFunctionCall(LLVMValueRef Fn, const char *Name, size_t NameLen) {
  auto targetName = StringRef(Name, NameLen);
  Function *F = unwrap<Function>(Fn);
  for (auto &BB : *F) {
    for (auto &I : BB) {
      if (auto *callInst = llvm::dyn_cast<llvm::CallBase>(&I)) {
        const llvm::Function *calledFunc = callInst->getCalledFunction();
        if (calledFunc && calledFunc->getName() == targetName) {
          // Found a call to the target function
          return wrap(callInst);
        }
      }
    }
  }

  return nullptr;
}

extern "C" bool LLVMRustConstIntGetZExtValue(LLVMValueRef CV, uint64_t *value) {
  auto C = unwrap<llvm::ConstantInt>(CV);
  if (C->getBitWidth() > 64)
    return false;
  *value = C->getZExtValue();
  return true;
}

// Returns true if both high and low were successfully set. Fails in case
// constant wasn’t any of the common sizes (1, 8, 16, 32, 64, 128 bits)
extern "C" bool LLVMRustConstInt128Get(LLVMValueRef CV, bool sext,
                                       uint64_t *high, uint64_t *low) {
  auto C = unwrap<llvm::ConstantInt>(CV);
  if (C->getBitWidth() > 128) {
    return false;
  }
  APInt AP;
  if (sext) {
    AP = C->getValue().sext(128);
  } else {
    AP = C->getValue().zext(128);
  }
  *low = AP.getLoBits(64).getZExtValue();
  *high = AP.getHiBits(64).getZExtValue();
  return true;
}

extern "C" void LLVMRustSetDSOLocal(LLVMValueRef Global, bool is_dso_local) {
  unwrap<GlobalValue>(Global)->setDSOLocal(is_dso_local);
}

struct LLVMRustModuleBuffer {
  std::string data;
};

extern "C" LLVMRustModuleBuffer *LLVMRustModuleBufferCreate(LLVMModuleRef M) {
  auto Ret = std::make_unique<LLVMRustModuleBuffer>();
  {
    auto OS = raw_string_ostream(Ret->data);
    WriteBitcodeToFile(*unwrap(M), OS);
  }
  return Ret.release();
}

extern "C" void LLVMRustModuleBufferFree(LLVMRustModuleBuffer *Buffer) {
  delete Buffer;
}

extern "C" const void *
LLVMRustModuleBufferPtr(const LLVMRustModuleBuffer *Buffer) {
  return Buffer->data.data();
}

extern "C" size_t LLVMRustModuleBufferLen(const LLVMRustModuleBuffer *Buffer) {
  return Buffer->data.length();
}

extern "C" uint64_t LLVMRustModuleCost(LLVMModuleRef M) {
  auto f = unwrap(M)->functions();
  return std::distance(std::begin(f), std::end(f));
}

extern "C" void LLVMRustModuleInstructionStats(LLVMModuleRef M,
                                               RustStringRef Str) {
  auto OS = RawRustStringOstream(Str);
  auto JOS = llvm::json::OStream(OS);
  auto Module = unwrap(M);

  JOS.object([&] {
    JOS.attribute("module", Module->getName());
    JOS.attribute("total", Module->getInstructionCount());
  });
}

// Vector reductions:
extern "C" LLVMValueRef LLVMRustBuildVectorReduceFAdd(LLVMBuilderRef B,
                                                      LLVMValueRef Acc,
                                                      LLVMValueRef Src) {
  return wrap(unwrap(B)->CreateFAddReduce(unwrap(Acc), unwrap(Src)));
}
extern "C" LLVMValueRef LLVMRustBuildVectorReduceFMul(LLVMBuilderRef B,
                                                      LLVMValueRef Acc,
                                                      LLVMValueRef Src) {
  return wrap(unwrap(B)->CreateFMulReduce(unwrap(Acc), unwrap(Src)));
}
extern "C" LLVMValueRef LLVMRustBuildVectorReduceAdd(LLVMBuilderRef B,
                                                     LLVMValueRef Src) {
  return wrap(unwrap(B)->CreateAddReduce(unwrap(Src)));
}
extern "C" LLVMValueRef LLVMRustBuildVectorReduceMul(LLVMBuilderRef B,
                                                     LLVMValueRef Src) {
  return wrap(unwrap(B)->CreateMulReduce(unwrap(Src)));
}
extern "C" LLVMValueRef LLVMRustBuildVectorReduceAnd(LLVMBuilderRef B,
                                                     LLVMValueRef Src) {
  return wrap(unwrap(B)->CreateAndReduce(unwrap(Src)));
}
extern "C" LLVMValueRef LLVMRustBuildVectorReduceOr(LLVMBuilderRef B,
                                                    LLVMValueRef Src) {
  return wrap(unwrap(B)->CreateOrReduce(unwrap(Src)));
}
extern "C" LLVMValueRef LLVMRustBuildVectorReduceXor(LLVMBuilderRef B,
                                                     LLVMValueRef Src) {
  return wrap(unwrap(B)->CreateXorReduce(unwrap(Src)));
}
extern "C" LLVMValueRef LLVMRustBuildVectorReduceMin(LLVMBuilderRef B,
                                                     LLVMValueRef Src,
                                                     bool IsSigned) {
  return wrap(unwrap(B)->CreateIntMinReduce(unwrap(Src), IsSigned));
}
extern "C" LLVMValueRef LLVMRustBuildVectorReduceMax(LLVMBuilderRef B,
                                                     LLVMValueRef Src,
                                                     bool IsSigned) {
  return wrap(unwrap(B)->CreateIntMaxReduce(unwrap(Src), IsSigned));
}
extern "C" LLVMValueRef
LLVMRustBuildVectorReduceFMin(LLVMBuilderRef B, LLVMValueRef Src, bool NoNaN) {
  Instruction *I = unwrap(B)->CreateFPMinReduce(unwrap(Src));
  I->setHasNoNaNs(NoNaN);
  return wrap(I);
}
extern "C" LLVMValueRef
LLVMRustBuildVectorReduceFMax(LLVMBuilderRef B, LLVMValueRef Src, bool NoNaN) {
  Instruction *I = unwrap(B)->CreateFPMaxReduce(unwrap(Src));
  I->setHasNoNaNs(NoNaN);
  return wrap(I);
}

extern "C" LLVMValueRef LLVMRustBuildMinNum(LLVMBuilderRef B, LLVMValueRef LHS,
                                            LLVMValueRef RHS) {
  return wrap(unwrap(B)->CreateMinNum(unwrap(LHS), unwrap(RHS)));
}
extern "C" LLVMValueRef LLVMRustBuildMaxNum(LLVMBuilderRef B, LLVMValueRef LHS,
                                            LLVMValueRef RHS) {
  return wrap(unwrap(B)->CreateMaxNum(unwrap(LHS), unwrap(RHS)));
}

// Transfers ownership of DiagnosticHandler unique_ptr to the caller.
extern "C" DiagnosticHandler *
LLVMRustContextGetDiagnosticHandler(LLVMContextRef C) {
  std::unique_ptr<DiagnosticHandler> DH = unwrap(C)->getDiagnosticHandler();
  return DH.release();
}

// Sets unique_ptr to object of DiagnosticHandler to provide custom diagnostic
// handling. Ownership of the handler is moved to the LLVMContext.
extern "C" void LLVMRustContextSetDiagnosticHandler(LLVMContextRef C,
                                                    DiagnosticHandler *DH) {
  unwrap(C)->setDiagnosticHandler(std::unique_ptr<DiagnosticHandler>(DH));
}

using LLVMDiagnosticHandlerTy = DiagnosticHandler::DiagnosticHandlerTy;

// Configures a diagnostic handler that invokes provided callback when a
// backend needs to emit a diagnostic.
//
// When RemarkAllPasses is true, remarks are enabled for all passes. Otherwise
// the RemarkPasses array specifies individual passes for which remarks will be
// enabled.
//
// If RemarkFilePath is not NULL, optimization remarks will be streamed directly
// into this file, bypassing the diagnostics handler.
extern "C" void LLVMRustContextConfigureDiagnosticHandler(
    LLVMContextRef C, LLVMDiagnosticHandlerTy DiagnosticHandlerCallback,
    void *DiagnosticHandlerContext, bool RemarkAllPasses,
    const char *const *RemarkPasses, size_t RemarkPassesLen,
    const char *RemarkFilePath, bool PGOAvailable) {

  class RustDiagnosticHandler final : public DiagnosticHandler {
  public:
    RustDiagnosticHandler(
        LLVMDiagnosticHandlerTy DiagnosticHandlerCallback,
        void *DiagnosticHandlerContext, bool RemarkAllPasses,
        std::vector<std::string> RemarkPasses,
        std::unique_ptr<ToolOutputFile> RemarksFile,
        std::unique_ptr<llvm::remarks::RemarkStreamer> RemarkStreamer,
        std::unique_ptr<LLVMRemarkStreamer> LlvmRemarkStreamer)
        : DiagnosticHandlerCallback(DiagnosticHandlerCallback),
          DiagnosticHandlerContext(DiagnosticHandlerContext),
          RemarkAllPasses(RemarkAllPasses),
          RemarkPasses(std::move(RemarkPasses)),
          RemarksFile(std::move(RemarksFile)),
          RemarkStreamer(std::move(RemarkStreamer)),
          LlvmRemarkStreamer(std::move(LlvmRemarkStreamer)) {}

    virtual bool handleDiagnostics(const DiagnosticInfo &DI) override {
      // If this diagnostic is one of the optimization remark kinds, we can
      // check if it's enabled before emitting it. This can avoid many
      // short-lived allocations when unpacking the diagnostic and converting
      // its various C++ strings into rust strings.
      // FIXME: some diagnostic infos still allocate before we get here, and
      // avoiding that would be good in the future. That will require changing a
      // few call sites in LLVM.
      if (auto *OptDiagBase = dyn_cast<DiagnosticInfoOptimizationBase>(&DI)) {
        if (OptDiagBase->isEnabled()) {
          if (this->LlvmRemarkStreamer) {
            this->LlvmRemarkStreamer->emit(*OptDiagBase);
            return true;
          }
        } else {
          return true;
        }
      }
      if (DiagnosticHandlerCallback) {
        DiagnosticHandlerCallback(&DI, DiagnosticHandlerContext);
        return true;
      }
      return false;
    }

    bool isAnalysisRemarkEnabled(StringRef PassName) const override {
      return isRemarkEnabled(PassName);
    }

    bool isMissedOptRemarkEnabled(StringRef PassName) const override {
      return isRemarkEnabled(PassName);
    }

    bool isPassedOptRemarkEnabled(StringRef PassName) const override {
      return isRemarkEnabled(PassName);
    }

    bool isAnyRemarkEnabled() const override {
      return RemarkAllPasses || !RemarkPasses.empty();
    }

  private:
    bool isRemarkEnabled(StringRef PassName) const {
      if (RemarkAllPasses)
        return true;

      for (auto &Pass : RemarkPasses)
        if (Pass == PassName)
          return true;

      return false;
    }

    LLVMDiagnosticHandlerTy DiagnosticHandlerCallback = nullptr;
    void *DiagnosticHandlerContext = nullptr;

    bool RemarkAllPasses = false;
    std::vector<std::string> RemarkPasses;

    // Since LlvmRemarkStreamer contains a pointer to RemarkStreamer, the
    // ordering of the three members below is important.
    std::unique_ptr<ToolOutputFile> RemarksFile;
    std::unique_ptr<llvm::remarks::RemarkStreamer> RemarkStreamer;
    std::unique_ptr<LLVMRemarkStreamer> LlvmRemarkStreamer;
  };

  std::vector<std::string> Passes;
  for (size_t I = 0; I != RemarkPassesLen; ++I) {
    Passes.push_back(RemarkPasses[I]);
  }

  // We need to hold onto both the streamers and the opened file
  std::unique_ptr<ToolOutputFile> RemarkFile;
  std::unique_ptr<llvm::remarks::RemarkStreamer> RemarkStreamer;
  std::unique_ptr<LLVMRemarkStreamer> LlvmRemarkStreamer;

  if (RemarkFilePath != nullptr) {
    if (PGOAvailable) {
      // Enable PGO hotness data for remarks, if available
      unwrap(C)->setDiagnosticsHotnessRequested(true);
    }

    std::error_code EC;
    RemarkFile = std::make_unique<ToolOutputFile>(
        RemarkFilePath, EC, llvm::sys::fs::OF_TextWithCRLF);
    if (EC) {
      std::string Error = std::string("Cannot create remark file: ") +
                          toString(errorCodeToError(EC));
      report_fatal_error(Twine(Error));
    }

    // Do not delete the file after we gather remarks
    RemarkFile->keep();

    auto RemarkSerializer = remarks::createRemarkSerializer(
        llvm::remarks::Format::YAML, remarks::SerializerMode::Separate,
        RemarkFile->os());
    if (Error E = RemarkSerializer.takeError()) {
      std::string Error = std::string("Cannot create remark serializer: ") +
                          toString(std::move(E));
      report_fatal_error(Twine(Error));
    }
    RemarkStreamer = std::make_unique<llvm::remarks::RemarkStreamer>(
        std::move(*RemarkSerializer));
    LlvmRemarkStreamer = std::make_unique<LLVMRemarkStreamer>(*RemarkStreamer);
  }

  unwrap(C)->setDiagnosticHandler(std::make_unique<RustDiagnosticHandler>(
      DiagnosticHandlerCallback, DiagnosticHandlerContext, RemarkAllPasses,
      Passes, std::move(RemarkFile), std::move(RemarkStreamer),
      std::move(LlvmRemarkStreamer)));
}

extern "C" void LLVMRustGetMangledName(LLVMValueRef V, RustStringRef Str) {
  auto OS = RawRustStringOstream(Str);
  GlobalValue *GV = unwrap<GlobalValue>(V);
  Mangler().getNameWithPrefix(OS, GV, true);
}

extern "C" int32_t LLVMRustGetElementTypeArgIndex(LLVMValueRef CallSite) {
  auto *CB = unwrap<CallBase>(CallSite);
  switch (CB->getIntrinsicID()) {
  case Intrinsic::arm_ldrex:
    return 0;
  case Intrinsic::arm_strex:
    return 1;
  }
  return -1;
}

extern "C" bool LLVMRustIsNonGVFunctionPointerTy(LLVMValueRef V) {
  if (unwrap<Value>(V)->getType()->isPointerTy()) {
    if (auto *GV = dyn_cast<GlobalValue>(unwrap<Value>(V))) {
      if (GV->getValueType()->isFunctionTy())
        return false;
    }
    return true;
  }
  return false;
}

extern "C" bool LLVMRustLLVMHasZlibCompressionForDebugSymbols() {
  return llvm::compression::zlib::isAvailable();
}

extern "C" bool LLVMRustLLVMHasZstdCompressionForDebugSymbols() {
  return llvm::compression::zstd::isAvailable();
}

extern "C" void LLVMRustSetNoSanitizeAddress(LLVMValueRef Global) {
  GlobalValue &GV = *unwrap<GlobalValue>(Global);
  GlobalValue::SanitizerMetadata MD;
  if (GV.hasSanitizerMetadata())
    MD = GV.getSanitizerMetadata();
  MD.NoAddress = true;
  MD.IsDynInit = false;
  GV.setSanitizerMetadata(MD);
}

extern "C" void LLVMRustSetNoSanitizeHWAddress(LLVMValueRef Global) {
  GlobalValue &GV = *unwrap<GlobalValue>(Global);
  GlobalValue::SanitizerMetadata MD;
  if (GV.hasSanitizerMetadata())
    MD = GV.getSanitizerMetadata();
  MD.NoHWAddress = true;
  GV.setSanitizerMetadata(MD);
}