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usr / src / contrib / llvm-project / llvm / lib / Target / WebAssembly /

📁 ..
📁 AsmParser
📁 Disassembler
📁 MCTargetDesc
📄 README.txt(8.34 KB)
📁 TargetInfo
📄 WebAssembly.h(4.05 KB)
📄 WebAssembly.td(4.85 KB)
📄 WebAssemblyAddMissingPrototypes.cpp(5.41 KB)
📄 WebAssemblyArgumentMove.cpp(3.36 KB)
📄 WebAssemblyAsmPrinter.cpp(16.09 KB)
📄 WebAssemblyAsmPrinter.h(3.12 KB)
📄 WebAssemblyCFGSort.cpp(15.94 KB)
📄 WebAssemblyCFGStackify.cpp(55.56 KB)
📄 WebAssemblyDebugFixup.cpp(5.4 KB)
📄 WebAssemblyDebugValueManager.cpp(1.77 KB)
📄 WebAssemblyDebugValueManager.h(1.13 KB)
📄 WebAssemblyExceptionInfo.cpp(6.23 KB)
📄 WebAssemblyExceptionInfo.h(6.24 KB)
📄 WebAssemblyExplicitLocals.cpp(15.04 KB)
📄 WebAssemblyFastISel.cpp(40.39 KB)
📄 WebAssemblyFixBrTableDefaults.cpp(5.81 KB)
📄 WebAssemblyFixFunctionBitcasts.cpp(12.59 KB)
📄 WebAssemblyFixIrreducibleControlFlow.cpp(18.91 KB)
📄 WebAssemblyFrameLowering.cpp(12.68 KB)
📄 WebAssemblyFrameLowering.h(2.98 KB)
📄 WebAssemblyISD.def(1.17 KB)
📄 WebAssemblyISelDAGToDAG.cpp(9.08 KB)
📄 WebAssemblyISelLowering.cpp(68.59 KB)
📄 WebAssemblyISelLowering.h(5.85 KB)
📄 WebAssemblyInstrAtomics.td(48.5 KB)
📄 WebAssemblyInstrBulkMemory.td(2.84 KB)
📄 WebAssemblyInstrCall.td(3.21 KB)
📄 WebAssemblyInstrControl.td(7.93 KB)
📄 WebAssemblyInstrConv.td(14.1 KB)
📄 WebAssemblyInstrFloat.td(6.03 KB)
📄 WebAssemblyInstrFormats.td(3.1 KB)
📄 WebAssemblyInstrInfo.cpp(8.21 KB)
📄 WebAssemblyInstrInfo.h(2.63 KB)
📄 WebAssemblyInstrInfo.td(14.37 KB)
📄 WebAssemblyInstrInteger.td(6.05 KB)
📄 WebAssemblyInstrMemory.td(18.63 KB)
📄 WebAssemblyInstrRef.td(1.15 KB)
📄 WebAssemblyInstrSIMD.td(39.08 KB)
📄 WebAssemblyLateEHPrepare.cpp(14.57 KB)
📄 WebAssemblyLowerBrUnless.cpp(6.21 KB)
📄 WebAssemblyLowerEmscriptenEHSjLj.cpp(45.45 KB)
📄 WebAssemblyLowerGlobalDtors.cpp(7.79 KB)
📄 WebAssemblyMCInstLower.cpp(13.72 KB)
📄 WebAssemblyMCInstLower.h(1.63 KB)
📄 WebAssemblyMachineFunctionInfo.cpp(4.29 KB)
📄 WebAssemblyMachineFunctionInfo.h(6.75 KB)
📄 WebAssemblyMemIntrinsicResults.cpp(7.39 KB)
📄 WebAssemblyOptimizeLiveIntervals.cpp(4.61 KB)
📄 WebAssemblyOptimizeReturned.cpp(2.46 KB)
📄 WebAssemblyPeephole.cpp(6.33 KB)
📄 WebAssemblyPrepareForLiveIntervals.cpp(4.34 KB)
📄 WebAssemblyRegColoring.cpp(6.37 KB)
📄 WebAssemblyRegNumbering.cpp(3.86 KB)
📄 WebAssemblyRegStackify.cpp(38.22 KB)
📄 WebAssemblyRegisterInfo.cpp(6.21 KB)
📄 WebAssemblyRegisterInfo.h(1.74 KB)
📄 WebAssemblyRegisterInfo.td(2.83 KB)
📄 WebAssemblyReplacePhysRegs.cpp(3.89 KB)
📄 WebAssemblyRuntimeLibcallSignatures.cpp(33.82 KB)
📄 WebAssemblyRuntimeLibcallSignatures.h(1.37 KB)
📄 WebAssemblySelectionDAGInfo.cpp(2.57 KB)
📄 WebAssemblySelectionDAGInfo.h(1.94 KB)
📄 WebAssemblySetP2AlignOperands.cpp(3.32 KB)
📄 WebAssemblySubtarget.cpp(2.18 KB)
📄 WebAssemblySubtarget.h(3.88 KB)
📄 WebAssemblyTargetMachine.cpp(18.85 KB)
📄 WebAssemblyTargetMachine.h(2.29 KB)
📄 WebAssemblyTargetObjectFile.cpp(886 B)
📄 WebAssemblyTargetObjectFile.h(959 B)
📄 WebAssemblyTargetTransformInfo.cpp(2.9 KB)
📄 WebAssemblyTargetTransformInfo.h(2.5 KB)
📄 WebAssemblyUtilities.cpp(3.43 KB)
📄 WebAssemblyUtilities.h(1.8 KB)
📄 known_gcc_test_failures.txt(2.07 KB)

Editing: WebAssemblyLowerGlobalDtors.cpp

//===-- WebAssemblyLowerGlobalDtors.cpp - Lower @llvm.global_dtors --------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// Lower @llvm.global_dtors.
///
/// WebAssembly doesn't have a builtin way to invoke static destructors.
/// Implement @llvm.global_dtors by creating wrapper functions that are
/// registered in @llvm.global_ctors and which contain a call to
/// `__cxa_atexit` to register their destructor functions.
///
//===----------------------------------------------------------------------===//

#include "WebAssembly.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/ModuleUtils.h"
using namespace llvm;

#define DEBUG_TYPE "wasm-lower-global-dtors"

namespace {
class LowerGlobalDtors final : public ModulePass {
  StringRef getPassName() const override {
    return "WebAssembly Lower @llvm.global_dtors";
  }

void getAnalysisUsage(AnalysisUsage &AU) const override {
    AU.setPreservesCFG();
    ModulePass::getAnalysisUsage(AU);
  }

bool runOnModule(Module &M) override;

public:
  static char ID;
  LowerGlobalDtors() : ModulePass(ID) {}
};
} // End anonymous namespace

char LowerGlobalDtors::ID = 0;
INITIALIZE_PASS(LowerGlobalDtors, DEBUG_TYPE,
                "Lower @llvm.global_dtors for WebAssembly", false, false)

ModulePass *llvm::createWebAssemblyLowerGlobalDtors() {
  return new LowerGlobalDtors();
}

bool LowerGlobalDtors::runOnModule(Module &M) {
  LLVM_DEBUG(dbgs() << "********** Lower Global Destructors **********\n");

GlobalVariable *GV = M.getGlobalVariable("llvm.global_dtors");
  if (!GV || !GV->hasInitializer())
    return false;

const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
  if (!InitList)
    return false;

// Sanity-check @llvm.global_dtor's type.
  auto *ETy = dyn_cast<StructType>(InitList->getType()->getElementType());
  if (!ETy || ETy->getNumElements() != 3 ||
      !ETy->getTypeAtIndex(0U)->isIntegerTy() ||
      !ETy->getTypeAtIndex(1U)->isPointerTy() ||
      !ETy->getTypeAtIndex(2U)->isPointerTy())
    return false; // Not (int, ptr, ptr).

// Collect the contents of @llvm.global_dtors, ordered by priority. Within a
  // priority, sequences of destructors with the same associated object are
  // recorded so that we can register them as a group.
  std::map<
      uint16_t,
      std::vector<std::pair<Constant *, std::vector<Constant *>>>
  > DtorFuncs;
  for (Value *O : InitList->operands()) {
    auto *CS = dyn_cast<ConstantStruct>(O);
    if (!CS)
      continue; // Malformed.

auto *Priority = dyn_cast<ConstantInt>(CS->getOperand(0));
    if (!Priority)
      continue; // Malformed.
    uint16_t PriorityValue = Priority->getLimitedValue(UINT16_MAX);

Constant *DtorFunc = CS->getOperand(1);
    if (DtorFunc->isNullValue())
      break; // Found a null terminator, skip the rest.

Constant *Associated = CS->getOperand(2);
    Associated = cast<Constant>(Associated->stripPointerCasts());

auto &AtThisPriority = DtorFuncs[PriorityValue];
    if (AtThisPriority.empty() || AtThisPriority.back().first != Associated) {
        std::vector<Constant *> NewList;
        NewList.push_back(DtorFunc);
        AtThisPriority.push_back(std::make_pair(Associated, NewList));
    } else {
        AtThisPriority.back().second.push_back(DtorFunc);
    }
  }
  if (DtorFuncs.empty())
    return false;

// extern "C" int __cxa_atexit(void (*f)(void *), void *p, void *d);
  LLVMContext &C = M.getContext();
  PointerType *VoidStar = Type::getInt8PtrTy(C);
  Type *AtExitFuncArgs[] = {VoidStar};
  FunctionType *AtExitFuncTy =
      FunctionType::get(Type::getVoidTy(C), AtExitFuncArgs,
                        /*isVarArg=*/false);

FunctionCallee AtExit = M.getOrInsertFunction(
      "__cxa_atexit",
      FunctionType::get(Type::getInt32Ty(C),
                        {PointerType::get(AtExitFuncTy, 0), VoidStar, VoidStar},
                        /*isVarArg=*/false));

// Declare __dso_local.
  Constant *DsoHandle = M.getNamedValue("__dso_handle");
  if (!DsoHandle) {
    Type *DsoHandleTy = Type::getInt8Ty(C);
    GlobalVariable *Handle = new GlobalVariable(
        M, DsoHandleTy, /*isConstant=*/true,
        GlobalVariable::ExternalWeakLinkage, nullptr, "__dso_handle");
    Handle->setVisibility(GlobalVariable::HiddenVisibility);
    DsoHandle = Handle;
  }

// For each unique priority level and associated symbol, generate a function
  // to call all the destructors at that level, and a function to register the
  // first function with __cxa_atexit.
  for (auto &PriorityAndMore : DtorFuncs) {
    uint16_t Priority = PriorityAndMore.first;
    uint64_t Id = 0;
    auto &AtThisPriority = PriorityAndMore.second;
    for (auto &AssociatedAndMore : AtThisPriority) {
      Constant *Associated = AssociatedAndMore.first;
      auto ThisId = Id++;

Function *CallDtors = Function::Create(
          AtExitFuncTy, Function::PrivateLinkage,
          "call_dtors" +
              (Priority != UINT16_MAX ? (Twine(".") + Twine(Priority))
                                      : Twine()) +
              (AtThisPriority.size() > 1 ? Twine("$") + Twine(ThisId)
                                         : Twine()) +
              (!Associated->isNullValue() ? (Twine(".") + Associated->getName())
                                          : Twine()),
          &M);
      BasicBlock *BB = BasicBlock::Create(C, "body", CallDtors);
      FunctionType *VoidVoid = FunctionType::get(Type::getVoidTy(C),
                                                 /*isVarArg=*/false);

for (auto Dtor : reverse(AssociatedAndMore.second))
        CallInst::Create(VoidVoid, Dtor, "", BB);
      ReturnInst::Create(C, BB);

Function *RegisterCallDtors = Function::Create(
          VoidVoid, Function::PrivateLinkage,
          "register_call_dtors" +
              (Priority != UINT16_MAX ? (Twine(".") + Twine(Priority))
                                      : Twine()) +
              (AtThisPriority.size() > 1 ? Twine("$") + Twine(ThisId)
                                         : Twine()) +
              (!Associated->isNullValue() ? (Twine(".") + Associated->getName())
                                          : Twine()),
          &M);
      BasicBlock *EntryBB = BasicBlock::Create(C, "entry", RegisterCallDtors);
      BasicBlock *FailBB = BasicBlock::Create(C, "fail", RegisterCallDtors);
      BasicBlock *RetBB = BasicBlock::Create(C, "return", RegisterCallDtors);

Value *Null = ConstantPointerNull::get(VoidStar);
      Value *Args[] = {CallDtors, Null, DsoHandle};
      Value *Res = CallInst::Create(AtExit, Args, "call", EntryBB);
      Value *Cmp = new ICmpInst(*EntryBB, ICmpInst::ICMP_NE, Res,
                                Constant::getNullValue(Res->getType()));
      BranchInst::Create(FailBB, RetBB, Cmp, EntryBB);

// If `__cxa_atexit` hits out-of-memory, trap, so that we don't misbehave.
      // This should be very rare, because if the process is running out of
      // memory before main has even started, something is wrong.
      CallInst::Create(Intrinsic::getDeclaration(&M, Intrinsic::trap), "",
                       FailBB);
      new UnreachableInst(C, FailBB);

ReturnInst::Create(C, RetBB);

// Now register the registration function with @llvm.global_ctors.
      appendToGlobalCtors(M, RegisterCallDtors, Priority, Associated);
    }
  }

// Now that we've lowered everything, remove @llvm.global_dtors.
  GV->eraseFromParent();

return true;
}

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Editing: WebAssemblyLowerGlobalDtors.cpp

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