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-rw-r--r--llvm/lib/Target/WebAssembly/WebAssemblyLowerGlobalDtors.cpp210
1 files changed, 0 insertions, 210 deletions
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyLowerGlobalDtors.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyLowerGlobalDtors.cpp
deleted file mode 100644
index ca6f3f194645..000000000000
--- a/llvm/lib/Target/WebAssembly/WebAssemblyLowerGlobalDtors.cpp
+++ /dev/null
@@ -1,210 +0,0 @@
-//===-- 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"
-#include <map>
-
-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;
-
- // Validate @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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