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 "llvm/ADT/None.h"
16
17 namespace clang {
18 namespace clangd {
19 namespace {
20
toEquivClass(ASTContext & Ctx,QualType T)21 static 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(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
43 static llvm::Optional<QualType>
typeOfCompletion(const CodeCompletionResult & R)44 typeOfCompletion(const CodeCompletionResult &R) {
45 const NamedDecl *D = R.Declaration;
46 // Templates do not have a type on their own, look at the templated decl.
47 if (auto *Template = dyn_cast_or_null<TemplateDecl>(D))
48 D = Template->getTemplatedDecl();
49 auto *VD = dyn_cast_or_null<ValueDecl>(D);
50 if (!VD)
51 return llvm::None; // We handle only variables and functions below.
52 auto T = VD->getType();
53 if (T.isNull())
54 return llvm::None;
55 if (auto *FuncT = T->getAs<FunctionType>()) {
56 // Functions are a special case. They are completed as 'foo()' and we want
57 // to match their return type rather than the function type itself.
58 // FIXME(ibiryukov): in some cases, we might want to avoid completing `()`
59 // after the function name, e.g. `std::cout << std::endl`.
60 return FuncT->getReturnType();
61 }
62 return T;
63 }
64 } // namespace
65
encode(ASTContext & Ctx,QualType T)66 llvm::Optional<OpaqueType> OpaqueType::encode(ASTContext &Ctx, QualType T) {
67 if (T.isNull())
68 return None;
69 const Type *C = toEquivClass(Ctx, T);
70 if (!C)
71 return None;
72 llvm::SmallString<128> Encoded;
73 if (index::generateUSRForType(QualType(C, 0), Ctx, Encoded))
74 return None;
75 return OpaqueType(std::string(Encoded.str()));
76 }
77
OpaqueType(std::string Data)78 OpaqueType::OpaqueType(std::string Data) : Data(std::move(Data)) {}
79
fromType(ASTContext & Ctx,QualType Type)80 llvm::Optional<OpaqueType> OpaqueType::fromType(ASTContext &Ctx,
81 QualType Type) {
82 return encode(Ctx, Type);
83 }
84
85 llvm::Optional<OpaqueType>
fromCompletionResult(ASTContext & Ctx,const CodeCompletionResult & R)86 OpaqueType::fromCompletionResult(ASTContext &Ctx,
87 const CodeCompletionResult &R) {
88 auto T = typeOfCompletion(R);
89 if (!T)
90 return None;
91 return encode(Ctx, *T);
92 }
93
94 } // namespace clangd
95 } // namespace clang
96