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
InterpState(State & Parent,Program & P,InterpStack & Stk,Context & Ctx,SourceMapper * M)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
~InterpState()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
cleanup()36 void InterpState::cleanup() {
37 // As a last resort, make sure all pointers still pointing to a dead block
38 // don't point to it anymore.
39 for (DeadBlock *DB = DeadBlocks; DB; DB = DB->Next) {
40 for (Pointer *P = DB->B.Pointers; P; P = P->Next) {
41 P->PointeeStorage.BS.Pointee = nullptr;
42 }
43 }
44
45 Alloc.cleanup();
46 }
47
getCurrentFrame()48 Frame *InterpState::getCurrentFrame() {
49 if (Current && Current->Caller)
50 return Current;
51 return Parent.getCurrentFrame();
52 }
53
reportOverflow(const Expr * E,const llvm::APSInt & Value)54 bool InterpState::reportOverflow(const Expr *E, const llvm::APSInt &Value) {
55 QualType Type = E->getType();
56 CCEDiag(E, diag::note_constexpr_overflow) << Value << Type;
57 return noteUndefinedBehavior();
58 }
59
deallocate(Block * B)60 void InterpState::deallocate(Block *B) {
61 assert(B);
62 const Descriptor *Desc = B->getDescriptor();
63 assert(Desc);
64
65 if (B->hasPointers()) {
66 size_t Size = B->getSize();
67
68 // Allocate a new block, transferring over pointers.
69 char *Memory =
70 reinterpret_cast<char *>(std::malloc(sizeof(DeadBlock) + Size));
71 auto *D = new (Memory) DeadBlock(DeadBlocks, B);
72 std::memset(D->B.rawData(), 0, D->B.getSize());
73
74 // Move data and metadata from the old block to the new (dead)block.
75 if (B->IsInitialized && Desc->MoveFn) {
76 Desc->MoveFn(B, B->data(), D->data(), Desc);
77 if (Desc->getMetadataSize() > 0)
78 std::memcpy(D->rawData(), B->rawData(), Desc->getMetadataSize());
79 }
80 D->B.IsInitialized = B->IsInitialized;
81
82 // We moved the contents over to the DeadBlock.
83 B->IsInitialized = false;
84 } else if (B->IsInitialized) {
85 B->invokeDtor();
86 }
87 }
88
maybeDiagnoseDanglingAllocations()89 bool InterpState::maybeDiagnoseDanglingAllocations() {
90 bool NoAllocationsLeft = (Alloc.getNumAllocations() == 0);
91
92 if (!checkingPotentialConstantExpression()) {
93 for (const auto &It : Alloc.allocation_sites()) {
94 assert(It.second.size() > 0);
95
96 const Expr *Source = It.first;
97 CCEDiag(Source->getExprLoc(), diag::note_constexpr_memory_leak)
98 << (It.second.size() - 1) << Source->getSourceRange();
99 }
100 }
101 return NoAllocationsLeft;
102 }
103