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      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 <limits>
     11 #include "Function.h"
     12 #include "InterpFrame.h"
     13 #include "InterpStack.h"
     14 #include "Opcode.h"
     15 #include "PrimType.h"
     16 #include "Program.h"
     17 #include "State.h"
     18 
     19 using namespace clang;
     20 using namespace clang::interp;
     21 
     22 using APSInt = llvm::APSInt;
     23 
     24 InterpState::InterpState(State &Parent, Program &P, InterpStack &Stk,
     25                          Context &Ctx, SourceMapper *M)
     26     : Parent(Parent), M(M), P(P), Stk(Stk), Ctx(Ctx), Current(nullptr),
     27       CallStackDepth(Parent.getCallStackDepth() + 1) {}
     28 
     29 InterpState::~InterpState() {
     30   while (Current) {
     31     InterpFrame *Next = Current->Caller;
     32     delete Current;
     33     Current = Next;
     34   }
     35 
     36   while (DeadBlocks) {
     37     DeadBlock *Next = DeadBlocks->Next;
     38     free(DeadBlocks);
     39     DeadBlocks = Next;
     40   }
     41 }
     42 
     43 Frame *InterpState::getCurrentFrame() {
     44   if (Current && Current->Caller) {
     45     return Current;
     46   } else {
     47     return Parent.getCurrentFrame();
     48   }
     49 }
     50 
     51 bool InterpState::reportOverflow(const Expr *E, const llvm::APSInt &Value) {
     52   QualType Type = E->getType();
     53   CCEDiag(E, diag::note_constexpr_overflow) << Value << Type;
     54   return noteUndefinedBehavior();
     55 }
     56 
     57 void InterpState::deallocate(Block *B) {
     58   Descriptor *Desc = B->getDescriptor();
     59   if (B->hasPointers()) {
     60     size_t Size = B->getSize();
     61 
     62     // Allocate a new block, transferring over pointers.
     63     char *Memory = reinterpret_cast<char *>(malloc(sizeof(DeadBlock) + Size));
     64     auto *D = new (Memory) DeadBlock(DeadBlocks, B);
     65 
     66     // Move data from one block to another.
     67     if (Desc->MoveFn)
     68       Desc->MoveFn(B, B->data(), D->data(), Desc);
     69   } else {
     70     // Free storage, if necessary.
     71     if (Desc->DtorFn)
     72       Desc->DtorFn(B, B->data(), Desc);
     73   }
     74 }
     75