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
23 using namespace llvm;
24
25 #define DEBUG_TYPE "wasm-lower-reftypes-intptr-conv"
26
27 namespace {
28 class WebAssemblyLowerRefTypesIntPtrConv final : public FunctionPass {
getPassName() const29 StringRef getPassName() const override {
30 return "WebAssembly Lower RefTypes Int-Ptr Conversions";
31 }
32
33 bool runOnFunction(Function &MF) override;
34
35 public:
36 static char ID; // Pass identification
WebAssemblyLowerRefTypesIntPtrConv()37 WebAssemblyLowerRefTypesIntPtrConv() : FunctionPass(ID) {}
38 };
39 } // end anonymous namespace
40
41 char WebAssemblyLowerRefTypesIntPtrConv::ID = 0;
42 INITIALIZE_PASS(WebAssemblyLowerRefTypesIntPtrConv, DEBUG_TYPE,
43 "WebAssembly Lower RefTypes Int-Ptr Conversions", false, false)
44
createWebAssemblyLowerRefTypesIntPtrConv()45 FunctionPass *llvm::createWebAssemblyLowerRefTypesIntPtrConv() {
46 return new WebAssemblyLowerRefTypesIntPtrConv();
47 }
48
runOnFunction(Function & F)49 bool WebAssemblyLowerRefTypesIntPtrConv::runOnFunction(Function &F) {
50 LLVM_DEBUG(dbgs() << "********** Lower RefTypes IntPtr Convs **********\n"
51 "********** Function: "
52 << F.getName() << '\n');
53
54 // This function will check for uses of ptrtoint and inttoptr on reference
55 // types and replace them with a trap instruction.
56 //
57 // We replace the instruction by a trap instruction
58 // and its uses by null in the case of inttoptr and 0 in the
59 // case of ptrtoint.
60 std::set<Instruction *> worklist;
61
62 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
63 PtrToIntInst *PTI = dyn_cast<PtrToIntInst>(&*I);
64 IntToPtrInst *ITP = dyn_cast<IntToPtrInst>(&*I);
65 if (!(PTI && WebAssembly::isRefType(PTI->getPointerOperand()->getType())) &&
66 !(ITP && WebAssembly::isRefType(ITP->getDestTy())))
67 continue;
68
69 UndefValue *U = UndefValue::get(I->getType());
70 I->replaceAllUsesWith(U);
71
72 Function *TrapIntrin =
73 Intrinsic::getDeclaration(F.getParent(), Intrinsic::debugtrap);
74 CallInst::Create(TrapIntrin, {}, "", &*I);
75
76 worklist.insert(&*I);
77 }
78
79 // erase each instruction replaced by trap
80 for (Instruction *I : worklist)
81 I->eraseFromParent();
82
83 return !worklist.empty();
84 }
85