1 files changed, 0 insertions, 321 deletions
diff --git a/contrib/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp b/contrib/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
deleted file mode 100644
index b7fc65401fc4..000000000000
--- a/contrib/llvm/lib/Target/WebAssembly/WebAssemblyFixFunctionBitcasts.cpp
+++ /dev/null
@@ -1,321 +0,0 @@
-//===-- WebAssemblyFixFunctionBitcasts.cpp - Fix function bitcasts --------===//
-//
-// 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
-/// Fix bitcasted functions.
-///
-/// WebAssembly requires caller and callee signatures to match, however in LLVM,
-/// some amount of slop is vaguely permitted. Detect mismatch by looking for
-/// bitcasts of functions and rewrite them to use wrapper functions instead.
-///
-/// This doesn't catch all cases, such as when a function's address is taken in
-/// one place and casted in another, but it works for many common cases.
-///
-/// Note that LLVM already optimizes away function bitcasts in common cases by
-/// dropping arguments as needed, so this pass only ends up getting used in less
-/// common cases.
-///
-//===----------------------------------------------------------------------===//
-
-#include "WebAssembly.h"
-#include "llvm/IR/CallSite.h"
-#include "llvm/IR/Constants.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/Module.h"
-#include "llvm/IR/Operator.h"
-#include "llvm/Pass.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-using namespace llvm;
-
-#define DEBUG_TYPE "wasm-fix-function-bitcasts"
-
-namespace {
-class FixFunctionBitcasts final : public ModulePass {
-  StringRef getPassName() const override {
-    return "WebAssembly Fix Function Bitcasts";
-  }
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.setPreservesCFG();
-    ModulePass::getAnalysisUsage(AU);
-  }
-
-  bool runOnModule(Module &M) override;
-
-public:
-  static char ID;
-  FixFunctionBitcasts() : ModulePass(ID) {}
-};
-} // End anonymous namespace
-
-char FixFunctionBitcasts::ID = 0;
-INITIALIZE_PASS(FixFunctionBitcasts, DEBUG_TYPE,
-                "Fix mismatching bitcasts for WebAssembly", false, false)
-
-ModulePass *llvm::createWebAssemblyFixFunctionBitcasts() {
-  return new FixFunctionBitcasts();
-}
-
-// Recursively descend the def-use lists from V to find non-bitcast users of
-// bitcasts of V.
-static void findUses(Value *V, Function &F,
-                     SmallVectorImpl<std::pair<Use *, Function *>> &Uses,
-                     SmallPtrSetImpl<Constant *> &ConstantBCs) {
-  for (Use &U : V->uses()) {
-    if (auto *BC = dyn_cast<BitCastOperator>(U.getUser()))
-      findUses(BC, F, Uses, ConstantBCs);
-    else if (U.get()->getType() != F.getType()) {
-      CallSite CS(U.getUser());
-      if (!CS)
-        // Skip uses that aren't immediately called
-        continue;
-      Value *Callee = CS.getCalledValue();
-      if (Callee != V)
-        // Skip calls where the function isn't the callee
-        continue;
-      if (isa<Constant>(U.get())) {
-        // Only add constant bitcasts to the list once; they get RAUW'd
-        auto C = ConstantBCs.insert(cast<Constant>(U.get()));
-        if (!C.second)
-          continue;
-      }
-      Uses.push_back(std::make_pair(&U, &F));
-    }
-  }
-}
-
-// Create a wrapper function with type Ty that calls F (which may have a
-// different type). Attempt to support common bitcasted function idioms:
-//  - Call with more arguments than needed: arguments are dropped
-//  - Call with fewer arguments than needed: arguments are filled in with undef
-//  - Return value is not needed: drop it
-//  - Return value needed but not present: supply an undef
-//
-// If the all the argument types of trivially castable to one another (i.e.
-// I32 vs pointer type) then we don't create a wrapper at all (return nullptr
-// instead).
-//
-// If there is a type mismatch that we know would result in an invalid wasm
-// module then generate wrapper that contains unreachable (i.e. abort at
-// runtime).  Such programs are deep into undefined behaviour territory,
-// but we choose to fail at runtime rather than generate and invalid module
-// or fail at compiler time.  The reason we delay the error is that we want
-// to support the CMake which expects to be able to compile and link programs
-// that refer to functions with entirely incorrect signatures (this is how
-// CMake detects the existence of a function in a toolchain).
-//
-// For bitcasts that involve struct types we don't know at this stage if they
-// would be equivalent at the wasm level and so we can't know if we need to
-// generate a wrapper.
-static Function *createWrapper(Function *F, FunctionType *Ty) {
-  Module *M = F->getParent();
-
-  Function *Wrapper = Function::Create(Ty, Function::PrivateLinkage,
-                                       F->getName() + "_bitcast", M);
-  BasicBlock *BB = BasicBlock::Create(M->getContext(), "body", Wrapper);
-  const DataLayout &DL = BB->getModule()->getDataLayout();
-
-  // Determine what arguments to pass.
-  SmallVector<Value *, 4> Args;
-  Function::arg_iterator AI = Wrapper->arg_begin();
-  Function::arg_iterator AE = Wrapper->arg_end();
-  FunctionType::param_iterator PI = F->getFunctionType()->param_begin();
-  FunctionType::param_iterator PE = F->getFunctionType()->param_end();
-  bool TypeMismatch = false;
-  bool WrapperNeeded = false;
-
-  Type *ExpectedRtnType = F->getFunctionType()->getReturnType();
-  Type *RtnType = Ty->getReturnType();
-
-  if ((F->getFunctionType()->getNumParams() != Ty->getNumParams()) ||
-      (F->getFunctionType()->isVarArg() != Ty->isVarArg()) ||
-      (ExpectedRtnType != RtnType))
-    WrapperNeeded = true;
-
-  for (; AI != AE && PI != PE; ++AI, ++PI) {
-    Type *ArgType = AI->getType();
-    Type *ParamType = *PI;
-
-    if (ArgType == ParamType) {
-      Args.push_back(&*AI);
-    } else {
-      if (CastInst::isBitOrNoopPointerCastable(ArgType, ParamType, DL)) {
-        Instruction *PtrCast =
-            CastInst::CreateBitOrPointerCast(AI, ParamType, "cast");
-        BB->getInstList().push_back(PtrCast);
-        Args.push_back(PtrCast);
-      } else if (ArgType->isStructTy() || ParamType->isStructTy()) {
-        LLVM_DEBUG(dbgs() << "createWrapper: struct param type in bitcast: "
-                          << F->getName() << "\n");
-        WrapperNeeded = false;
-      } else {
-        LLVM_DEBUG(dbgs() << "createWrapper: arg type mismatch calling: "
-                          << F->getName() << "\n");
-        LLVM_DEBUG(dbgs() << "Arg[" << Args.size() << "] Expected: "
-                          << *ParamType << " Got: " << *ArgType << "\n");
-        TypeMismatch = true;
-        break;
-      }
-    }
-  }
-
-  if (WrapperNeeded && !TypeMismatch) {
-    for (; PI != PE; ++PI)
-      Args.push_back(UndefValue::get(*PI));
-    if (F->isVarArg())
-      for (; AI != AE; ++AI)
-        Args.push_back(&*AI);
-
-    CallInst *Call = CallInst::Create(F, Args, "", BB);
-
-    Type *ExpectedRtnType = F->getFunctionType()->getReturnType();
-    Type *RtnType = Ty->getReturnType();
-    // Determine what value to return.
-    if (RtnType->isVoidTy()) {
-      ReturnInst::Create(M->getContext(), BB);
-    } else if (ExpectedRtnType->isVoidTy()) {
-      LLVM_DEBUG(dbgs() << "Creating dummy return: " << *RtnType << "\n");
-      ReturnInst::Create(M->getContext(), UndefValue::get(RtnType), BB);
-    } else if (RtnType == ExpectedRtnType) {
-      ReturnInst::Create(M->getContext(), Call, BB);
-    } else if (CastInst::isBitOrNoopPointerCastable(ExpectedRtnType, RtnType,
-                                                    DL)) {
-      Instruction *Cast =
-          CastInst::CreateBitOrPointerCast(Call, RtnType, "cast");
-      BB->getInstList().push_back(Cast);
-      ReturnInst::Create(M->getContext(), Cast, BB);
-    } else if (RtnType->isStructTy() || ExpectedRtnType->isStructTy()) {
-      LLVM_DEBUG(dbgs() << "createWrapper: struct return type in bitcast: "
-                        << F->getName() << "\n");
-      WrapperNeeded = false;
-    } else {
-      LLVM_DEBUG(dbgs() << "createWrapper: return type mismatch calling: "
-                        << F->getName() << "\n");
-      LLVM_DEBUG(dbgs() << "Expected: " << *ExpectedRtnType
-                        << " Got: " << *RtnType << "\n");
-      TypeMismatch = true;
-    }
-  }
-
-  if (TypeMismatch) {
-    // Create a new wrapper that simply contains `unreachable`.
-    Wrapper->eraseFromParent();
-    Wrapper = Function::Create(Ty, Function::PrivateLinkage,
-                               F->getName() + "_bitcast_invalid", M);
-    BasicBlock *BB = BasicBlock::Create(M->getContext(), "body", Wrapper);
-    new UnreachableInst(M->getContext(), BB);
-    Wrapper->setName(F->getName() + "_bitcast_invalid");
-  } else if (!WrapperNeeded) {
-    LLVM_DEBUG(dbgs() << "createWrapper: no wrapper needed: " << F->getName()
-                      << "\n");
-    Wrapper->eraseFromParent();
-    return nullptr;
-  }
-  LLVM_DEBUG(dbgs() << "createWrapper: " << F->getName() << "\n");
-  return Wrapper;
-}
-
-// Test whether a main function with type FuncTy should be rewritten to have
-// type MainTy.
-static bool shouldFixMainFunction(FunctionType *FuncTy, FunctionType *MainTy) {
-  // Only fix the main function if it's the standard zero-arg form. That way,
-  // the standard cases will work as expected, and users will see signature
-  // mismatches from the linker for non-standard cases.
-  return FuncTy->getReturnType() == MainTy->getReturnType() &&
-         FuncTy->getNumParams() == 0 &&
-         !FuncTy->isVarArg();
-}
-
-bool FixFunctionBitcasts::runOnModule(Module &M) {
-  LLVM_DEBUG(dbgs() << "********** Fix Function Bitcasts **********\n");
-
-  Function *Main = nullptr;
-  CallInst *CallMain = nullptr;
-  SmallVector<std::pair<Use *, Function *>, 0> Uses;
-  SmallPtrSet<Constant *, 2> ConstantBCs;
-
-  // Collect all the places that need wrappers.
-  for (Function &F : M) {
-    findUses(&F, F, Uses, ConstantBCs);
-
-    // If we have a "main" function, and its type isn't
-    // "int main(int argc, char *argv[])", create an artificial call with it
-    // bitcasted to that type so that we generate a wrapper for it, so that
-    // the C runtime can call it.
-    if (F.getName() == "main") {
-      Main = &F;
-      LLVMContext &C = M.getContext();
-      Type *MainArgTys[] = {Type::getInt32Ty(C),
-                            PointerType::get(Type::getInt8PtrTy(C), 0)};
-      FunctionType *MainTy = FunctionType::get(Type::getInt32Ty(C), MainArgTys,
-                                               /*isVarArg=*/false);
-      if (shouldFixMainFunction(F.getFunctionType(), MainTy)) {
-        LLVM_DEBUG(dbgs() << "Found `main` function with incorrect type: "
-                          << *F.getFunctionType() << "\n");
-        Value *Args[] = {UndefValue::get(MainArgTys[0]),
-                         UndefValue::get(MainArgTys[1])};
-        Value *Casted =
-            ConstantExpr::getBitCast(Main, PointerType::get(MainTy, 0));
-        CallMain = CallInst::Create(MainTy, Casted, Args, "call_main");
-        Use *UseMain = &CallMain->getOperandUse(2);
-        Uses.push_back(std::make_pair(UseMain, &F));
-      }
-    }
-  }
-
-  DenseMap<std::pair<Function *, FunctionType *>, Function *> Wrappers;
-
-  for (auto &UseFunc : Uses) {
-    Use *U = UseFunc.first;
-    Function *F = UseFunc.second;
-    auto *PTy = cast<PointerType>(U->get()->getType());
-    auto *Ty = dyn_cast<FunctionType>(PTy->getElementType());
-
-    // If the function is casted to something like i8* as a "generic pointer"
-    // to be later casted to something else, we can't generate a wrapper for it.
-    // Just ignore such casts for now.
-    if (!Ty)
-      continue;
-
-    auto Pair = Wrappers.insert(std::make_pair(std::make_pair(F, Ty), nullptr));
-    if (Pair.second)
-      Pair.first->second = createWrapper(F, Ty);
-
-    Function *Wrapper = Pair.first->second;
-    if (!Wrapper)
-      continue;
-
-    if (isa<Constant>(U->get()))
-      U->get()->replaceAllUsesWith(Wrapper);
-    else
-      U->set(Wrapper);
-  }
-
-  // If we created a wrapper for main, rename the wrapper so that it's the
-  // one that gets called from startup.
-  if (CallMain) {
-    Main->setName("__original_main");
-    auto *MainWrapper =
-        cast<Function>(CallMain->getCalledValue()->stripPointerCasts());
-    delete CallMain;
-    if (Main->isDeclaration()) {
-      // The wrapper is not needed in this case as we don't need to export
-      // it to anyone else.
-      MainWrapper->eraseFromParent();
-    } else {
-      // Otherwise give the wrapper the same linkage as the original main
-      // function, so that it can be called from the same places.
-      MainWrapper->setName("main");
-      MainWrapper->setLinkage(Main->getLinkage());
-      MainWrapper->setVisibility(Main->getVisibility());
-    }
-  }
-
-  return true;
-}