1//===- SemaSYCL.cpp - Semantic Analysis for SYCL constructs ---------------===//
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// This implements Semantic Analysis for SYCL constructs.
9//===----------------------------------------------------------------------===//
10
11#include "clang/AST/Mangle.h"
12#include "clang/Sema/Sema.h"
13#include "clang/Sema/SemaDiagnostic.h"
14
15using namespace clang;
16
17// -----------------------------------------------------------------------------
18// SYCL device specific diagnostics implementation
19// -----------------------------------------------------------------------------
20
21Sema::SemaDiagnosticBuilder Sema::SYCLDiagIfDeviceCode(SourceLocation Loc,
22                                                       unsigned DiagID) {
23  assert(getLangOpts().SYCLIsDevice &&
24         "Should only be called during SYCL compilation");
25  FunctionDecl *FD = dyn_cast<FunctionDecl>(getCurLexicalContext());
26  SemaDiagnosticBuilder::Kind DiagKind = [this, FD] {
27    if (!FD)
28      return SemaDiagnosticBuilder::K_Nop;
29    if (getEmissionStatus(FD) == Sema::FunctionEmissionStatus::Emitted)
30      return SemaDiagnosticBuilder::K_ImmediateWithCallStack;
31    return SemaDiagnosticBuilder::K_Deferred;
32  }();
33  return SemaDiagnosticBuilder(DiagKind, Loc, DiagID, FD, *this);
34}
35
36static bool isZeroSizedArray(Sema &SemaRef, QualType Ty) {
37  if (const auto *CAT = SemaRef.getASTContext().getAsConstantArrayType(Ty))
38    return CAT->getSize() == 0;
39  return false;
40}
41
42void Sema::deepTypeCheckForSYCLDevice(SourceLocation UsedAt,
43                                      llvm::DenseSet<QualType> Visited,
44                                      ValueDecl *DeclToCheck) {
45  assert(getLangOpts().SYCLIsDevice &&
46         "Should only be called during SYCL compilation");
47  // Emit notes only for the first discovered declaration of unsupported type
48  // to avoid mess of notes. This flag is to track that error already happened.
49  bool NeedToEmitNotes = true;
50
51  auto Check = [&](QualType TypeToCheck, const ValueDecl *D) {
52    bool ErrorFound = false;
53    if (isZeroSizedArray(*this, TypeToCheck)) {
54      SYCLDiagIfDeviceCode(UsedAt, diag::err_typecheck_zero_array_size) << 1;
55      ErrorFound = true;
56    }
57    // Checks for other types can also be done here.
58    if (ErrorFound) {
59      if (NeedToEmitNotes) {
60        if (auto *FD = dyn_cast<FieldDecl>(D))
61          SYCLDiagIfDeviceCode(FD->getLocation(),
62                               diag::note_illegal_field_declared_here)
63              << FD->getType()->isPointerType() << FD->getType();
64        else
65          SYCLDiagIfDeviceCode(D->getLocation(), diag::note_declared_at);
66      }
67    }
68
69    return ErrorFound;
70  };
71
72  // In case we have a Record used do the DFS for a bad field.
73  SmallVector<const ValueDecl *, 4> StackForRecursion;
74  StackForRecursion.push_back(DeclToCheck);
75
76  // While doing DFS save how we get there to emit a nice set of notes.
77  SmallVector<const FieldDecl *, 4> History;
78  History.push_back(nullptr);
79
80  do {
81    const ValueDecl *Next = StackForRecursion.pop_back_val();
82    if (!Next) {
83      assert(!History.empty());
84      // Found a marker, we have gone up a level.
85      History.pop_back();
86      continue;
87    }
88    QualType NextTy = Next->getType();
89
90    if (!Visited.insert(NextTy).second)
91      continue;
92
93    auto EmitHistory = [&]() {
94      // The first element is always nullptr.
95      for (uint64_t Index = 1; Index < History.size(); ++Index) {
96        SYCLDiagIfDeviceCode(History[Index]->getLocation(),
97                             diag::note_within_field_of_type)
98            << History[Index]->getType();
99      }
100    };
101
102    if (Check(NextTy, Next)) {
103      if (NeedToEmitNotes)
104        EmitHistory();
105      NeedToEmitNotes = false;
106    }
107
108    // In case pointer/array/reference type is met get pointee type, then
109    // proceed with that type.
110    while (NextTy->isAnyPointerType() || NextTy->isArrayType() ||
111           NextTy->isReferenceType()) {
112      if (NextTy->isArrayType())
113        NextTy = QualType{NextTy->getArrayElementTypeNoTypeQual(), 0};
114      else
115        NextTy = NextTy->getPointeeType();
116      if (Check(NextTy, Next)) {
117        if (NeedToEmitNotes)
118          EmitHistory();
119        NeedToEmitNotes = false;
120      }
121    }
122
123    if (const auto *RecDecl = NextTy->getAsRecordDecl()) {
124      if (auto *NextFD = dyn_cast<FieldDecl>(Next))
125        History.push_back(NextFD);
126      // When nullptr is discovered, this means we've gone back up a level, so
127      // the history should be cleaned.
128      StackForRecursion.push_back(nullptr);
129      llvm::copy(RecDecl->fields(), std::back_inserter(StackForRecursion));
130    }
131  } while (!StackForRecursion.empty());
132}
133