1//=== WebAssemblyLowerRefTypesIntPtrConv.cpp -
2// Lower IntToPtr and PtrToInt on Reference Types ---===//
3//
4// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
5// See https://llvm.org/LICENSE.txt for license information.
6// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7//
8//===----------------------------------------------------------------------===//
9///
10/// \file
11/// Lowers IntToPtr and PtrToInt instructions on reference types to
12/// Trap instructions since they have been allowed to operate
13/// on non-integral pointers.
14///
15//===----------------------------------------------------------------------===//
16
17#include "Utils/WebAssemblyTypeUtilities.h"
18#include "WebAssembly.h"
19#include "WebAssemblySubtarget.h"
20#include "llvm/IR/InstIterator.h"
21#include "llvm/Pass.h"
22#include <set>
23
24using namespace llvm;
25
26#define DEBUG_TYPE "wasm-lower-reftypes-intptr-conv"
27
28namespace {
29class WebAssemblyLowerRefTypesIntPtrConv final : public FunctionPass {
30 StringRef getPassName() const override {
31 return "WebAssembly Lower RefTypes Int-Ptr Conversions";
32 }
33
34 bool runOnFunction(Function &MF) override;
35
36public:
37 static char ID; // Pass identification
38 WebAssemblyLowerRefTypesIntPtrConv() : FunctionPass(ID) {}
39};
40} // end anonymous namespace
41
42char WebAssemblyLowerRefTypesIntPtrConv::ID = 0;
43INITIALIZE_PASS(WebAssemblyLowerRefTypesIntPtrConv, DEBUG_TYPE,
44 "WebAssembly Lower RefTypes Int-Ptr Conversions", false, false)
45
46FunctionPass *llvm::createWebAssemblyLowerRefTypesIntPtrConv() {
47 return new WebAssemblyLowerRefTypesIntPtrConv();
48}
49
50bool WebAssemblyLowerRefTypesIntPtrConv::runOnFunction(Function &F) {
51 LLVM_DEBUG(dbgs() << "********** Lower RefTypes IntPtr Convs **********\n"
52 "********** Function: "
53 << F.getName() << '\n');
54
55 // This function will check for uses of ptrtoint and inttoptr on reference
56 // types and replace them with a trap instruction.
57 //
58 // We replace the instruction by a trap instruction
59 // and its uses by null in the case of inttoptr and 0 in the
60 // case of ptrtoint.
61 std::set<Instruction *> worklist;
62
63 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
64 PtrToIntInst *PTI = dyn_cast<PtrToIntInst>(Val: &*I);
65 IntToPtrInst *ITP = dyn_cast<IntToPtrInst>(Val: &*I);
66 if (!(PTI && WebAssembly::isWebAssemblyReferenceType(
67 Ty: PTI->getPointerOperand()->getType())) &&
68 !(ITP && WebAssembly::isWebAssemblyReferenceType(Ty: ITP->getDestTy())))
69 continue;
70
71 I->replaceAllUsesWith(V: PoisonValue::get(T: I->getType()));
72
73 Function *TrapIntrin =
74 Intrinsic::getOrInsertDeclaration(M: F.getParent(), id: Intrinsic::debugtrap);
75 CallInst::Create(Func: TrapIntrin, Args: {}, NameStr: "", InsertBefore: I->getIterator());
76
77 worklist.insert(x: &*I);
78 }
79
80 // erase each instruction replaced by trap
81 for (Instruction *I : worklist)
82 I->eraseFromParent();
83
84 return !worklist.empty();
85}
86