1 //===--- HLSLExternalSemaSource.cpp - HLSL Sema Source --------------------===//
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 //
10 //===----------------------------------------------------------------------===//
11 
12 #include "clang/Sema/HLSLExternalSemaSource.h"
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/DeclCXX.h"
15 #include "clang/Basic/AttrKinds.h"
16 #include "clang/Sema/Sema.h"
17 
18 using namespace clang;
19 
20 HLSLExternalSemaSource::~HLSLExternalSemaSource() {}
21 
22 void HLSLExternalSemaSource::InitializeSema(Sema &S) {
23   SemaPtr = &S;
24   ASTContext &AST = SemaPtr->getASTContext();
25   IdentifierInfo &HLSL = AST.Idents.get("hlsl", tok::TokenKind::identifier);
26   HLSLNamespace =
27       NamespaceDecl::Create(AST, AST.getTranslationUnitDecl(), false,
28                             SourceLocation(), SourceLocation(), &HLSL, nullptr);
29   HLSLNamespace->setImplicit(true);
30   AST.getTranslationUnitDecl()->addDecl(HLSLNamespace);
31   defineHLSLVectorAlias();
32 
33   // This adds a `using namespace hlsl` directive. In DXC, we don't put HLSL's
34   // built in types inside a namespace, but we are planning to change that in
35   // the near future. In order to be source compatible older versions of HLSL
36   // will need to implicitly use the hlsl namespace. For now in clang everything
37   // will get added to the namespace, and we can remove the using directive for
38   // future language versions to match HLSL's evolution.
39   auto *UsingDecl = UsingDirectiveDecl::Create(
40       AST, AST.getTranslationUnitDecl(), SourceLocation(), SourceLocation(),
41       NestedNameSpecifierLoc(), SourceLocation(), HLSLNamespace,
42       AST.getTranslationUnitDecl());
43 
44   AST.getTranslationUnitDecl()->addDecl(UsingDecl);
45 }
46 
47 void HLSLExternalSemaSource::defineHLSLVectorAlias() {
48   ASTContext &AST = SemaPtr->getASTContext();
49 
50   llvm::SmallVector<NamedDecl *> TemplateParams;
51 
52   auto *TypeParam = TemplateTypeParmDecl::Create(
53       AST, HLSLNamespace, SourceLocation(), SourceLocation(), 0, 0,
54       &AST.Idents.get("element", tok::TokenKind::identifier), false, false);
55   TypeParam->setDefaultArgument(AST.getTrivialTypeSourceInfo(AST.FloatTy));
56 
57   TemplateParams.emplace_back(TypeParam);
58 
59   auto *SizeParam = NonTypeTemplateParmDecl::Create(
60       AST, HLSLNamespace, SourceLocation(), SourceLocation(), 0, 1,
61       &AST.Idents.get("element_count", tok::TokenKind::identifier), AST.IntTy,
62       false, AST.getTrivialTypeSourceInfo(AST.IntTy));
63   Expr *LiteralExpr =
64       IntegerLiteral::Create(AST, llvm::APInt(AST.getIntWidth(AST.IntTy), 4),
65                              AST.IntTy, SourceLocation());
66   SizeParam->setDefaultArgument(LiteralExpr);
67   TemplateParams.emplace_back(SizeParam);
68 
69   auto *ParamList =
70       TemplateParameterList::Create(AST, SourceLocation(), SourceLocation(),
71                                     TemplateParams, SourceLocation(), nullptr);
72 
73   IdentifierInfo &II = AST.Idents.get("vector", tok::TokenKind::identifier);
74 
75   QualType AliasType = AST.getDependentSizedExtVectorType(
76       AST.getTemplateTypeParmType(0, 0, false, TypeParam),
77       DeclRefExpr::Create(
78           AST, NestedNameSpecifierLoc(), SourceLocation(), SizeParam, false,
79           DeclarationNameInfo(SizeParam->getDeclName(), SourceLocation()),
80           AST.IntTy, VK_LValue),
81       SourceLocation());
82 
83   auto *Record = TypeAliasDecl::Create(AST, HLSLNamespace, SourceLocation(),
84                                        SourceLocation(), &II,
85                                        AST.getTrivialTypeSourceInfo(AliasType));
86   Record->setImplicit(true);
87 
88   auto *Template =
89       TypeAliasTemplateDecl::Create(AST, HLSLNamespace, SourceLocation(),
90                                     Record->getIdentifier(), ParamList, Record);
91 
92   Record->setDescribedAliasTemplate(Template);
93   Template->setImplicit(true);
94   Template->setLexicalDeclContext(Record->getDeclContext());
95   HLSLNamespace->addDecl(Template);
96 }
97