1 //===- ValueList.cpp - Internal BitcodeReader implementation --------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "ValueList.h"
10 #include "llvm/IR/Argument.h"
11 #include "llvm/IR/Constant.h"
12 #include "llvm/IR/Constants.h"
13 #include "llvm/IR/GlobalValue.h"
14 #include "llvm/IR/Instruction.h"
15 #include "llvm/IR/Type.h"
16 #include "llvm/IR/User.h"
17 #include "llvm/IR/Value.h"
18 #include "llvm/Support/Casting.h"
19 #include "llvm/Support/Error.h"
20 #include "llvm/Support/ErrorHandling.h"
21 #include <cstddef>
22
23 using namespace llvm;
24
assignValue(unsigned Idx,Value * V,unsigned TypeID)25 Error BitcodeReaderValueList::assignValue(unsigned Idx, Value *V,
26 unsigned TypeID) {
27 if (Idx == size()) {
28 push_back(V, TypeID);
29 return Error::success();
30 }
31
32 if (Idx >= size())
33 resize(Idx + 1);
34
35 auto &Old = ValuePtrs[Idx];
36 if (!Old.first) {
37 Old.first = V;
38 Old.second = TypeID;
39 return Error::success();
40 }
41
42 assert(!isa<Constant>(&*Old.first) && "Shouldn't update constant");
43 // If there was a forward reference to this value, replace it.
44 Value *PrevVal = Old.first;
45 if (PrevVal->getType() != V->getType())
46 return createStringError(
47 std::errc::illegal_byte_sequence,
48 "Assigned value does not match type of forward declaration");
49 Old.first->replaceAllUsesWith(V);
50 PrevVal->deleteValue();
51 return Error::success();
52 }
53
getValueFwdRef(unsigned Idx,Type * Ty,unsigned TyID,BasicBlock * ConstExprInsertBB)54 Value *BitcodeReaderValueList::getValueFwdRef(unsigned Idx, Type *Ty,
55 unsigned TyID,
56 BasicBlock *ConstExprInsertBB) {
57 // Bail out for a clearly invalid value.
58 if (Idx >= RefsUpperBound)
59 return nullptr;
60
61 if (Idx >= size())
62 resize(Idx + 1);
63
64 if (Value *V = ValuePtrs[Idx].first) {
65 // If the types don't match, it's invalid.
66 if (Ty && Ty != V->getType())
67 return nullptr;
68
69 Expected<Value *> MaybeV = MaterializeValueFn(Idx, ConstExprInsertBB);
70 if (!MaybeV) {
71 // TODO: We might want to propagate the precise error message here.
72 consumeError(MaybeV.takeError());
73 return nullptr;
74 }
75 return MaybeV.get();
76 }
77
78 // No type specified, must be invalid reference.
79 if (!Ty)
80 return nullptr;
81
82 // Create and return a placeholder, which will later be RAUW'd.
83 Value *V = new Argument(Ty);
84 ValuePtrs[Idx] = {V, TyID};
85 return V;
86 }
87