1 | //===- TemplatingUtils.h - Templater for text templates -----------------===// |
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 | #ifndef MLIR_LIB_TARGET_IRDLTOCPP_TEMPLATINGUTILS_H |
10 | #define MLIR_LIB_TARGET_IRDLTOCPP_TEMPLATINGUTILS_H |
11 | |
12 | #include "llvm/ADT/SmallString.h" |
13 | #include "llvm/ADT/StringMap.h" |
14 | #include "llvm/ADT/StringRef.h" |
15 | #include "llvm/Support/ErrorHandling.h" |
16 | #include "llvm/Support/raw_ostream.h" |
17 | #include <variant> |
18 | |
19 | namespace mlir::irdl::detail { |
20 | |
21 | /// A dictionary stores a mapping of template variable names to their assigned |
22 | /// string values. |
23 | using dictionary = llvm::StringMap<llvm::SmallString<8>>; |
24 | |
25 | /// Template Code as used by IRDL-to-Cpp. |
26 | /// |
27 | /// For efficiency, produces a bytecode representation of an input template. |
28 | /// - LiteralToken: A contiguous stream of characters to be printed |
29 | /// - ReplacementToken: A template variable that will be replaced |
30 | class Template { |
31 | public: |
32 | Template(llvm::StringRef str) { |
33 | bool processingReplacementToken = false; |
34 | while (!str.empty()) { |
35 | auto [token, remainder] = str.split(Separator: "__" ); |
36 | |
37 | if (processingReplacementToken) { |
38 | assert(!token.empty() && "replacement name cannot be empty" ); |
39 | bytecode.emplace_back(args: ReplacementToken{.keyName: token}); |
40 | } else { |
41 | if (!token.empty()) |
42 | bytecode.emplace_back(args: LiteralToken{.text: token}); |
43 | } |
44 | |
45 | processingReplacementToken = !processingReplacementToken; |
46 | str = remainder; |
47 | } |
48 | } |
49 | |
50 | /// Render will apply a dictionary to the Template and send the rendered |
51 | /// result to the specified output stream. |
52 | void render(llvm::raw_ostream &out, const dictionary &replacements) const { |
53 | for (auto instruction : bytecode) { |
54 | if (auto *inst = std::get_if<LiteralToken>(ptr: &instruction)) { |
55 | out << inst->text; |
56 | continue; |
57 | } |
58 | |
59 | if (auto *inst = std::get_if<ReplacementToken>(ptr: &instruction)) { |
60 | auto replacement = replacements.find(Key: inst->keyName); |
61 | #ifndef NDEBUG |
62 | if (replacement == replacements.end()) { |
63 | llvm::errs() << "Missing template key: " << inst->keyName << "\n" ; |
64 | llvm_unreachable("Missing template key" ); |
65 | } |
66 | #endif |
67 | out << replacement->second; |
68 | continue; |
69 | } |
70 | |
71 | llvm_unreachable("non-exhaustive bytecode visit" ); |
72 | } |
73 | } |
74 | |
75 | private: |
76 | struct LiteralToken { |
77 | llvm::StringRef text; |
78 | }; |
79 | |
80 | struct ReplacementToken { |
81 | llvm::StringRef keyName; |
82 | }; |
83 | |
84 | std::vector<std::variant<LiteralToken, ReplacementToken>> bytecode; |
85 | }; |
86 | |
87 | } // namespace mlir::irdl::detail |
88 | |
89 | #endif // MLIR_LIB_TARGET_IRDLTOCPP_TEMPLATINGUTILS_H |
90 | |