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
24 using namespace llvm;
25
26 #define DEBUG_TYPE "wasm-lower-reftypes-intptr-conv"
27
28 namespace {
29 class WebAssemblyLowerRefTypesIntPtrConv final : public FunctionPass {
getPassName() const30 StringRef getPassName() const override {
31 return "WebAssembly Lower RefTypes Int-Ptr Conversions";
32 }
33
34 bool runOnFunction(Function &MF) override;
35
36 public:
37 static char ID; // Pass identification
WebAssemblyLowerRefTypesIntPtrConv()38 WebAssemblyLowerRefTypesIntPtrConv() : FunctionPass(ID) {}
39 };
40 } // end anonymous namespace
41
42 char WebAssemblyLowerRefTypesIntPtrConv::ID = 0;
43 INITIALIZE_PASS(WebAssemblyLowerRefTypesIntPtrConv, DEBUG_TYPE,
44 "WebAssembly Lower RefTypes Int-Ptr Conversions", false, false)
45
createWebAssemblyLowerRefTypesIntPtrConv()46 FunctionPass *llvm::createWebAssemblyLowerRefTypesIntPtrConv() {
47 return new WebAssemblyLowerRefTypesIntPtrConv();
48 }
49
runOnFunction(Function & F)50 bool 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>(&*I);
65 IntToPtrInst *ITP = dyn_cast<IntToPtrInst>(&*I);
66 if (!(PTI && WebAssembly::isWebAssemblyReferenceType(
67 PTI->getPointerOperand()->getType())) &&
68 !(ITP && WebAssembly::isWebAssemblyReferenceType(ITP->getDestTy())))
69 continue;
70
71 UndefValue *U = UndefValue::get(I->getType());
72 I->replaceAllUsesWith(U);
73
74 Function *TrapIntrin =
75 Intrinsic::getDeclaration(F.getParent(), Intrinsic::debugtrap);
76 CallInst::Create(TrapIntrin, {}, "", I->getIterator());
77
78 worklist.insert(&*I);
79 }
80
81 // erase each instruction replaced by trap
82 for (Instruction *I : worklist)
83 I->eraseFromParent();
84
85 return !worklist.empty();
86 }
87