You've already forked linux-packaging-mono
Imported Upstream version 5.18.0.167
Former-commit-id: 289509151e0fee68a1b591a20c9f109c3c789d3a
This commit is contained in:
Xamarin Public Jenkins (auto-signing)
parent
e19d552987
commit
b084638f15
@ -1,191 +0,0 @@
|
||||
//===-- WebAssemblyLowerGlobalDtors.cpp - Lower @llvm.global_dtors --------===//
|
||||
//
|
||||
// The LLVM Compiler Infrastructure
|
||||
//
|
||||
// This file is distributed under the University of Illinois Open Source
|
||||
// License. See LICENSE.TXT for details.
|
||||
//
|
||||
//===----------------------------------------------------------------------===//
|
||||
///
|
||||
/// \file
|
||||
/// \brief 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/IR/Constants.h"
|
||||
#include "llvm/IR/Instructions.h"
|
||||
#include "llvm/IR/Intrinsics.h"
|
||||
#include "llvm/IR/Module.h"
|
||||
#include "llvm/Transforms/Utils/ModuleUtils.h"
|
||||
#include "llvm/Pass.h"
|
||||
#include "llvm/ADT/MapVector.h"
|
||||
#include "llvm/Support/Debug.h"
|
||||
#include "llvm/Support/raw_ostream.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;
|
||||
ModulePass *llvm::createWebAssemblyLowerGlobalDtors() {
|
||||
return new LowerGlobalDtors();
|
||||
}
|
||||
|
||||
bool LowerGlobalDtors::runOnModule(Module &M) {
|
||||
GlobalVariable *GV = M.getGlobalVariable("llvm.global_dtors");
|
||||
if (!GV)
|
||||
return false;
|
||||
|
||||
const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
|
||||
if (!InitList)
|
||||
return false;
|
||||
|
||||
// Sanity-check @llvm.global_dtor's type.
|
||||
StructType *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, collated by priority and
|
||||
// associated symbol.
|
||||
std::map<uint16_t, MapVector<Constant *, std::vector<Constant *> > > DtorFuncs;
|
||||
for (Value *O : InitList->operands()) {
|
||||
ConstantStruct *CS = dyn_cast<ConstantStruct>(O);
|
||||
if (!CS) continue; // Malformed.
|
||||
|
||||
ConstantInt *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->stripPointerCastsNoFollowAliases());
|
||||
|
||||
DtorFuncs[PriorityValue][Associated].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);
|
||||
|
||||
Type *AtExitArgs[] = {
|
||||
PointerType::get(AtExitFuncTy, 0),
|
||||
VoidStar,
|
||||
VoidStar
|
||||
};
|
||||
FunctionType *AtExitTy = FunctionType::get(
|
||||
Type::getInt32Ty(C),
|
||||
AtExitArgs,
|
||||
/*isVarArg=*/false);
|
||||
Constant *AtExit = M.getOrInsertFunction("__cxa_atexit", AtExitTy);
|
||||
|
||||
// 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;
|
||||
for (auto &AssociatedAndMore : PriorityAndMore.second) {
|
||||
Constant *Associated = AssociatedAndMore.first;
|
||||
|
||||
Function *CallDtors = Function::Create(
|
||||
AtExitFuncTy, Function::PrivateLinkage,
|
||||
"call_dtors" +
|
||||
(Priority != UINT16_MAX ?
|
||||
(Twine(".") + Twine(Priority)) : Twine()) +
|
||||
(!Associated->isNullValue() ?
|
||||
(Twine(".") + Associated->getName()) : Twine()),
|
||||
&M);
|
||||
BasicBlock *BB = BasicBlock::Create(C, "body", CallDtors);
|
||||
|
||||
for (auto Dtor : AssociatedAndMore.second)
|
||||
CallInst::Create(Dtor, "", BB);
|
||||
ReturnInst::Create(C, BB);
|
||||
|
||||
FunctionType *VoidVoid = FunctionType::get(Type::getVoidTy(C),
|
||||
/*isVarArg=*/false);
|
||||
Function *RegisterCallDtors = Function::Create(
|
||||
VoidVoid, Function::PrivateLinkage,
|
||||
"register_call_dtors" +
|
||||
(Priority != UINT16_MAX ?
|
||||
(Twine(".") + Twine(Priority)) : 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;
|
||||
}
|
||||
Reference in New Issue
Block a user