1 //===--- InterpState.cpp - Interpreter for the constexpr VM -----*- C++ -*-===//
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 "InterpState.h"
10 #include "InterpFrame.h"
11 #include "InterpStack.h"
12 #include "Program.h"
13 #include "State.h"
14 
15 using namespace clang;
16 using namespace clang::interp;
17 
18 InterpState::InterpState(State &Parent, Program &P, InterpStack &Stk,
19                          Context &Ctx, SourceMapper *M)
20     : Parent(Parent), M(M), P(P), Stk(Stk), Ctx(Ctx), Current(nullptr) {}
21 
22 InterpState::~InterpState() {
23   while (Current) {
24     InterpFrame *Next = Current->Caller;
25     delete Current;
26     Current = Next;
27   }
28 
29   while (DeadBlocks) {
30     DeadBlock *Next = DeadBlocks->Next;
31     std::free(DeadBlocks);
32     DeadBlocks = Next;
33   }
34 }
35 
36 Frame *InterpState::getCurrentFrame() {
37   if (Current && Current->Caller)
38     return Current;
39   return Parent.getCurrentFrame();
40 }
41 
42 bool InterpState::reportOverflow(const Expr *E, const llvm::APSInt &Value) {
43   QualType Type = E->getType();
44   CCEDiag(E, diag::note_constexpr_overflow) << Value << Type;
45   return noteUndefinedBehavior();
46 }
47 
48 void InterpState::deallocate(Block *B) {
49   assert(B);
50   const Descriptor *Desc = B->getDescriptor();
51   assert(Desc);
52 
53   if (B->hasPointers()) {
54     size_t Size = B->getSize();
55 
56     // Allocate a new block, transferring over pointers.
57     char *Memory =
58         reinterpret_cast<char *>(std::malloc(sizeof(DeadBlock) + Size));
59     auto *D = new (Memory) DeadBlock(DeadBlocks, B);
60 
61     // Move data from one block to another.
62     if (Desc->MoveFn)
63       Desc->MoveFn(B, B->data(), D->data(), Desc);
64   } else {
65     // Free storage, if necessary.
66     if (Desc->DtorFn)
67       Desc->DtorFn(B, B->data(), Desc);
68   }
69 }
70