1//===--- ExpectedTypes.cpp ---------------------------------------*- 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 "ExpectedTypes.h"
10#include "clang/AST/ASTContext.h"
11#include "clang/AST/DeclTemplate.h"
12#include "clang/AST/Type.h"
13#include "clang/Index/USRGeneration.h"
14#include "clang/Sema/CodeCompleteConsumer.h"
15#include <optional>
16
17namespace clang {
18namespace clangd {
19namespace {
20
21static const Type *toEquivClass(ASTContext &Ctx, QualType T) {
22 if (T.isNull() || T->isDependentType())
23 return nullptr;
24 // Drop references, we do not handle reference inits properly anyway.
25 T = T.getCanonicalType().getNonReferenceType();
26 // Numeric types are the simplest case.
27 if (T->isBooleanType())
28 return Ctx.BoolTy.getTypePtr();
29 if (T->isIntegerType() && !T->isEnumeralType())
30 return Ctx.IntTy.getTypePtr(); // All integers are equivalent.
31 if (T->isFloatingType() && !T->isComplexType())
32 return Ctx.FloatTy.getTypePtr(); // All floats are equivalent.
33
34 // Do some simple transformations.
35 if (T->isArrayType()) // Decay arrays to pointers.
36 return Ctx.getPointerType(T: QualType(T->getArrayElementTypeNoTypeQual(), 0))
37 .getTypePtr();
38 // Drop the qualifiers and return the resulting type.
39 // FIXME: also drop qualifiers from pointer types, e.g. 'const T* => T*'
40 return T.getTypePtr();
41}
42
43static std::optional<QualType> typeOfCompletion(const CodeCompletionResult &R) {
44 const NamedDecl *D = R.Declaration;
45 // Templates do not have a type on their own, look at the templated decl.
46 if (auto *Template = dyn_cast_or_null<TemplateDecl>(Val: D))
47 D = Template->getTemplatedDecl();
48 auto *VD = dyn_cast_or_null<ValueDecl>(Val: D);
49 if (!VD)
50 return std::nullopt; // We handle only variables and functions below.
51 auto T = VD->getType();
52 if (T.isNull())
53 return std::nullopt;
54 if (auto *FuncT = T->getAs<FunctionType>()) {
55 // Functions are a special case. They are completed as 'foo()' and we want
56 // to match their return type rather than the function type itself.
57 // FIXME(ibiryukov): in some cases, we might want to avoid completing `()`
58 // after the function name, e.g. `std::cout << std::endl`.
59 return FuncT->getReturnType();
60 }
61 return T;
62}
63} // namespace
64
65std::optional<OpaqueType> OpaqueType::encode(ASTContext &Ctx, QualType T) {
66 if (T.isNull())
67 return std::nullopt;
68 const Type *C = toEquivClass(Ctx, T);
69 if (!C)
70 return std::nullopt;
71 llvm::SmallString<128> Encoded;
72 if (index::generateUSRForType(T: QualType(C, 0), Ctx, Buf&: Encoded))
73 return std::nullopt;
74 return OpaqueType(std::string(Encoded));
75}
76
77OpaqueType::OpaqueType(std::string Data) : Data(std::move(Data)) {}
78
79std::optional<OpaqueType> OpaqueType::fromType(ASTContext &Ctx, QualType Type) {
80 return encode(Ctx, T: Type);
81}
82
83std::optional<OpaqueType>
84OpaqueType::fromCompletionResult(ASTContext &Ctx,
85 const CodeCompletionResult &R) {
86 auto T = typeOfCompletion(R);
87 if (!T)
88 return std::nullopt;
89 return encode(Ctx, T: *T);
90}
91
92} // namespace clangd
93} // namespace clang
94

source code of clang-tools-extra/clangd/ExpectedTypes.cpp