1//===- ClangDiff.cpp - compare source files by AST nodes ------*- 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// This file implements a tool for syntax tree based comparison using
10// Tooling/ASTDiff.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Tooling/ASTDiff/ASTDiff.h"
15#include "clang/Tooling/CommonOptionsParser.h"
16#include "clang/Tooling/Tooling.h"
17#include "llvm/Support/CommandLine.h"
18
19using namespace llvm;
20using namespace clang;
21using namespace clang::tooling;
22
23static cl::OptionCategory ClangDiffCategory("clang-diff options");
24
25static cl::opt<bool>
26 ASTDump("ast-dump",
27 cl::desc("Print the internal representation of the AST."),
28 cl::init(Val: false), cl::cat(ClangDiffCategory));
29
30static cl::opt<bool> ASTDumpJson(
31 "ast-dump-json",
32 cl::desc("Print the internal representation of the AST as JSON."),
33 cl::init(Val: false), cl::cat(ClangDiffCategory));
34
35static cl::opt<bool> PrintMatches("dump-matches",
36 cl::desc("Print the matched nodes."),
37 cl::init(Val: false), cl::cat(ClangDiffCategory));
38
39static cl::opt<bool> HtmlDiff("html",
40 cl::desc("Output a side-by-side diff in HTML."),
41 cl::init(Val: false), cl::cat(ClangDiffCategory));
42
43static cl::opt<std::string> SourcePath(cl::Positional, cl::desc("<source>"),
44 cl::Required,
45 cl::cat(ClangDiffCategory));
46
47static cl::opt<std::string> DestinationPath(cl::Positional,
48 cl::desc("<destination>"),
49 cl::Optional,
50 cl::cat(ClangDiffCategory));
51
52static cl::opt<std::string> StopAfter("stop-diff-after",
53 cl::desc("<topdown|bottomup>"),
54 cl::Optional, cl::init(Val: ""),
55 cl::cat(ClangDiffCategory));
56
57static cl::opt<int> MaxSize("s", cl::desc("<maxsize>"), cl::Optional,
58 cl::init(Val: -1), cl::cat(ClangDiffCategory));
59
60static cl::opt<std::string> BuildPath("p", cl::desc("Build path"), cl::init(Val: ""),
61 cl::Optional, cl::cat(ClangDiffCategory));
62
63static cl::list<std::string> ArgsAfter(
64 "extra-arg",
65 cl::desc("Additional argument to append to the compiler command line"),
66 cl::cat(ClangDiffCategory));
67
68static cl::list<std::string> ArgsBefore(
69 "extra-arg-before",
70 cl::desc("Additional argument to prepend to the compiler command line"),
71 cl::cat(ClangDiffCategory));
72
73static void addExtraArgs(std::unique_ptr<CompilationDatabase> &Compilations) {
74 if (!Compilations)
75 return;
76 auto AdjustingCompilations =
77 std::make_unique<ArgumentsAdjustingCompilations>(
78 args: std::move(Compilations));
79 AdjustingCompilations->appendArgumentsAdjuster(
80 Adjuster: getInsertArgumentAdjuster(Extra: ArgsBefore, Pos: ArgumentInsertPosition::BEGIN));
81 AdjustingCompilations->appendArgumentsAdjuster(
82 Adjuster: getInsertArgumentAdjuster(Extra: ArgsAfter, Pos: ArgumentInsertPosition::END));
83 Compilations = std::move(AdjustingCompilations);
84}
85
86static std::unique_ptr<ASTUnit>
87getAST(const std::unique_ptr<CompilationDatabase> &CommonCompilations,
88 const StringRef Filename) {
89 std::string ErrorMessage;
90 std::unique_ptr<CompilationDatabase> Compilations;
91 if (!CommonCompilations) {
92 Compilations = CompilationDatabase::autoDetectFromSource(
93 SourceFile: BuildPath.empty() ? Filename : BuildPath, ErrorMessage);
94 if (!Compilations) {
95 llvm::errs()
96 << "Error while trying to load a compilation database, running "
97 "without flags.\n"
98 << ErrorMessage;
99 Compilations =
100 std::make_unique<clang::tooling::FixedCompilationDatabase>(
101 args: ".", args: std::vector<std::string>());
102 }
103 }
104 addExtraArgs(Compilations);
105 std::array<std::string, 1> Files = {._M_elems: {std::string(Filename)}};
106 ClangTool Tool(Compilations ? *Compilations : *CommonCompilations, Files);
107 std::vector<std::unique_ptr<ASTUnit>> ASTs;
108 Tool.buildASTs(ASTs);
109 if (ASTs.size() != Files.size())
110 return nullptr;
111 return std::move(ASTs[0]);
112}
113
114static char hexdigit(int N) { return N &= 0xf, N + (N < 10 ? '0' : 'a' - 10); }
115
116static const char HtmlDiffHeader[] = R"(
117<html>
118<head>
119<meta charset='utf-8'/>
120<style>
121span.d { color: red; }
122span.u { color: #cc00cc; }
123span.i { color: green; }
124span.m { font-weight: bold; }
125span { font-weight: normal; color: black; }
126div.code {
127 width: 48%;
128 height: 98%;
129 overflow: scroll;
130 float: left;
131 padding: 0 0 0.5% 0.5%;
132 border: solid 2px LightGrey;
133 border-radius: 5px;
134}
135</style>
136</head>
137<script type='text/javascript'>
138highlightStack = []
139function clearHighlight() {
140 while (highlightStack.length) {
141 var [l, r] = highlightStack.pop()
142 document.getElementById(l).style.backgroundColor = 'inherit'
143 if (r[1] != '-')
144 document.getElementById(r).style.backgroundColor = 'inherit'
145 }
146}
147function highlight(event) {
148 var id = event.target['id']
149 doHighlight(id)
150}
151function doHighlight(id) {
152 clearHighlight()
153 source = document.getElementById(id)
154 if (!source.attributes['tid'])
155 return
156 var mapped = source
157 while (mapped && mapped.parentElement && mapped.attributes['tid'].value.substr(1) === '-1')
158 mapped = mapped.parentElement
159 var tid = null, target = null
160 if (mapped) {
161 tid = mapped.attributes['tid'].value
162 target = document.getElementById(tid)
163 }
164 if (source.parentElement && source.parentElement.classList.contains('code'))
165 return
166 source.style.backgroundColor = 'lightgrey'
167 source.scrollIntoView()
168 if (target) {
169 if (mapped === source)
170 target.style.backgroundColor = 'lightgrey'
171 target.scrollIntoView()
172 }
173 highlightStack.push([id, tid])
174 location.hash = '#' + id
175}
176function scrollToBoth() {
177 doHighlight(location.hash.substr(1))
178}
179function changed(elem) {
180 return elem.classList.length == 0
181}
182function nextChangedNode(prefix, increment, number) {
183 do {
184 number += increment
185 var elem = document.getElementById(prefix + number)
186 } while(elem && !changed(elem))
187 return elem ? number : null
188}
189function handleKey(e) {
190 var down = e.code === "KeyJ"
191 var up = e.code === "KeyK"
192 if (!down && !up)
193 return
194 var id = highlightStack[0] ? highlightStack[0][0] : 'R0'
195 var oldelem = document.getElementById(id)
196 var number = parseInt(id.substr(1))
197 var increment = down ? 1 : -1
198 var lastnumber = number
199 var prefix = id[0]
200 do {
201 number = nextChangedNode(prefix, increment, number)
202 var elem = document.getElementById(prefix + number)
203 if (up && elem) {
204 while (elem.parentElement && changed(elem.parentElement))
205 elem = elem.parentElement
206 number = elem.id.substr(1)
207 }
208 } while ((down && id !== 'R0' && oldelem.contains(elem)))
209 if (!number)
210 number = lastnumber
211 elem = document.getElementById(prefix + number)
212 doHighlight(prefix + number)
213}
214window.onload = scrollToBoth
215window.onkeydown = handleKey
216</script>
217<body>
218<div onclick='highlight(event)'>
219)";
220
221static void printHtml(raw_ostream &OS, char C) {
222 switch (C) {
223 case '&':
224 OS << "&amp;";
225 break;
226 case '<':
227 OS << "&lt;";
228 break;
229 case '>':
230 OS << "&gt;";
231 break;
232 case '\'':
233 OS << "&#x27;";
234 break;
235 case '"':
236 OS << "&quot;";
237 break;
238 default:
239 OS << C;
240 }
241}
242
243static void printHtml(raw_ostream &OS, const StringRef Str) {
244 for (char C : Str)
245 printHtml(OS, C);
246}
247
248static std::string getChangeKindAbbr(diff::ChangeKind Kind) {
249 switch (Kind) {
250 case diff::None:
251 return "";
252 case diff::Delete:
253 return "d";
254 case diff::Update:
255 return "u";
256 case diff::Insert:
257 return "i";
258 case diff::Move:
259 return "m";
260 case diff::UpdateMove:
261 return "u m";
262 }
263 llvm_unreachable("Invalid enumeration value.");
264}
265
266static unsigned printHtmlForNode(raw_ostream &OS, const diff::ASTDiff &Diff,
267 diff::SyntaxTree &Tree, bool IsLeft,
268 diff::NodeId Id, unsigned Offset) {
269 const diff::Node &Node = Tree.getNode(Id);
270 char MyTag, OtherTag;
271 diff::NodeId LeftId, RightId;
272 diff::NodeId TargetId = Diff.getMapped(SourceTree: Tree, Id);
273 if (IsLeft) {
274 MyTag = 'L';
275 OtherTag = 'R';
276 LeftId = Id;
277 RightId = TargetId;
278 } else {
279 MyTag = 'R';
280 OtherTag = 'L';
281 LeftId = TargetId;
282 RightId = Id;
283 }
284 unsigned Begin, End;
285 std::tie(args&: Begin, args&: End) = Tree.getSourceRangeOffsets(N: Node);
286 const SourceManager &SrcMgr = Tree.getASTContext().getSourceManager();
287 auto Code = SrcMgr.getBufferOrFake(FID: SrcMgr.getMainFileID()).getBuffer();
288 for (; Offset < Begin; ++Offset)
289 printHtml(OS, C: Code[Offset]);
290 OS << "<span id='" << MyTag << Id << "' "
291 << "tid='" << OtherTag << TargetId << "' ";
292 OS << "title='";
293 printHtml(OS, Str: Node.getTypeLabel());
294 OS << "\n" << LeftId << " -> " << RightId;
295 std::string Value = Tree.getNodeValue(Node);
296 if (!Value.empty()) {
297 OS << "\n";
298 printHtml(OS, Str: Value);
299 }
300 OS << "'";
301 if (Node.Change != diff::None)
302 OS << " class='" << getChangeKindAbbr(Kind: Node.Change) << "'";
303 OS << ">";
304
305 for (diff::NodeId Child : Node.Children)
306 Offset = printHtmlForNode(OS, Diff, Tree, IsLeft, Id: Child, Offset);
307
308 for (; Offset < End; ++Offset)
309 printHtml(OS, C: Code[Offset]);
310 if (Id == Tree.getRootId()) {
311 End = Code.size();
312 for (; Offset < End; ++Offset)
313 printHtml(OS, C: Code[Offset]);
314 }
315 OS << "</span>";
316 return Offset;
317}
318
319static void printJsonString(raw_ostream &OS, const StringRef Str) {
320 for (signed char C : Str) {
321 switch (C) {
322 case '"':
323 OS << R"(\")";
324 break;
325 case '\\':
326 OS << R"(\\)";
327 break;
328 case '\n':
329 OS << R"(\n)";
330 break;
331 case '\t':
332 OS << R"(\t)";
333 break;
334 default:
335 if ('\x00' <= C && C <= '\x1f') {
336 OS << R"(\u00)" << hexdigit(N: C >> 4) << hexdigit(N: C);
337 } else {
338 OS << C;
339 }
340 }
341 }
342}
343
344static void printNodeAttributes(raw_ostream &OS, diff::SyntaxTree &Tree,
345 diff::NodeId Id) {
346 const diff::Node &N = Tree.getNode(Id);
347 OS << R"("id":)" << int(Id);
348 OS << R"(,"type":")" << N.getTypeLabel() << '"';
349 auto Offsets = Tree.getSourceRangeOffsets(N);
350 OS << R"(,"begin":)" << Offsets.first;
351 OS << R"(,"end":)" << Offsets.second;
352 std::string Value = Tree.getNodeValue(Node: N);
353 if (!Value.empty()) {
354 OS << R"(,"value":")";
355 printJsonString(OS, Str: Value);
356 OS << '"';
357 }
358}
359
360static void printNodeAsJson(raw_ostream &OS, diff::SyntaxTree &Tree,
361 diff::NodeId Id) {
362 const diff::Node &N = Tree.getNode(Id);
363 OS << "{";
364 printNodeAttributes(OS, Tree, Id);
365 auto Identifier = N.getIdentifier();
366 auto QualifiedIdentifier = N.getQualifiedIdentifier();
367 if (Identifier) {
368 OS << R"(,"identifier":")";
369 printJsonString(OS, Str: *Identifier);
370 OS << R"(")";
371 if (QualifiedIdentifier && *Identifier != *QualifiedIdentifier) {
372 OS << R"(,"qualified_identifier":")";
373 printJsonString(OS, Str: *QualifiedIdentifier);
374 OS << R"(")";
375 }
376 }
377 OS << R"(,"children":[)";
378 if (N.Children.size() > 0) {
379 printNodeAsJson(OS, Tree, Id: N.Children[0]);
380 for (size_t I = 1, E = N.Children.size(); I < E; ++I) {
381 OS << ",";
382 printNodeAsJson(OS, Tree, Id: N.Children[I]);
383 }
384 }
385 OS << "]}";
386}
387
388static void printNode(raw_ostream &OS, diff::SyntaxTree &Tree,
389 diff::NodeId Id) {
390 if (Id.isInvalid()) {
391 OS << "None";
392 return;
393 }
394 OS << Tree.getNode(Id).getTypeLabel();
395 std::string Value = Tree.getNodeValue(Id);
396 if (!Value.empty())
397 OS << ": " << Value;
398 OS << "(" << Id << ")";
399}
400
401static void printTree(raw_ostream &OS, diff::SyntaxTree &Tree) {
402 for (diff::NodeId Id : Tree) {
403 for (int I = 0; I < Tree.getNode(Id).Depth; ++I)
404 OS << " ";
405 printNode(OS, Tree, Id);
406 OS << "\n";
407 }
408}
409
410static void printDstChange(raw_ostream &OS, diff::ASTDiff &Diff,
411 diff::SyntaxTree &SrcTree, diff::SyntaxTree &DstTree,
412 diff::NodeId Dst) {
413 const diff::Node &DstNode = DstTree.getNode(Id: Dst);
414 diff::NodeId Src = Diff.getMapped(SourceTree: DstTree, Id: Dst);
415 switch (DstNode.Change) {
416 case diff::None:
417 break;
418 case diff::Delete:
419 llvm_unreachable("The destination tree can't have deletions.");
420 case diff::Update:
421 OS << "Update ";
422 printNode(OS, Tree&: SrcTree, Id: Src);
423 OS << " to " << DstTree.getNodeValue(Id: Dst) << "\n";
424 break;
425 case diff::Insert:
426 case diff::Move:
427 case diff::UpdateMove:
428 if (DstNode.Change == diff::Insert)
429 OS << "Insert";
430 else if (DstNode.Change == diff::Move)
431 OS << "Move";
432 else if (DstNode.Change == diff::UpdateMove)
433 OS << "Update and Move";
434 OS << " ";
435 printNode(OS, Tree&: DstTree, Id: Dst);
436 OS << " into ";
437 printNode(OS, Tree&: DstTree, Id: DstNode.Parent);
438 OS << " at " << DstTree.findPositionInParent(Id: Dst) << "\n";
439 break;
440 }
441}
442
443int main(int argc, const char **argv) {
444 std::string ErrorMessage;
445 std::unique_ptr<CompilationDatabase> CommonCompilations =
446 FixedCompilationDatabase::loadFromCommandLine(Argc&: argc, Argv: argv, ErrorMsg&: ErrorMessage);
447 if (!CommonCompilations && !ErrorMessage.empty())
448 llvm::errs() << ErrorMessage;
449 cl::HideUnrelatedOptions(Category&: ClangDiffCategory);
450 if (!cl::ParseCommandLineOptions(argc, argv)) {
451 cl::PrintOptionValues();
452 return 1;
453 }
454
455 addExtraArgs(Compilations&: CommonCompilations);
456
457 if (ASTDump || ASTDumpJson) {
458 if (!DestinationPath.empty()) {
459 llvm::errs() << "Error: Please specify exactly one filename.\n";
460 return 1;
461 }
462 std::unique_ptr<ASTUnit> AST = getAST(CommonCompilations, Filename: SourcePath);
463 if (!AST)
464 return 1;
465 diff::SyntaxTree Tree(AST->getASTContext());
466 if (ASTDump) {
467 printTree(OS&: llvm::outs(), Tree);
468 return 0;
469 }
470 llvm::outs() << R"({"filename":")";
471 printJsonString(OS&: llvm::outs(), Str: SourcePath);
472 llvm::outs() << R"(","root":)";
473 printNodeAsJson(OS&: llvm::outs(), Tree, Id: Tree.getRootId());
474 llvm::outs() << "}\n";
475 return 0;
476 }
477
478 if (DestinationPath.empty()) {
479 llvm::errs() << "Error: Exactly two paths are required.\n";
480 return 1;
481 }
482
483 std::unique_ptr<ASTUnit> Src = getAST(CommonCompilations, Filename: SourcePath);
484 std::unique_ptr<ASTUnit> Dst = getAST(CommonCompilations, Filename: DestinationPath);
485 if (!Src || !Dst)
486 return 1;
487
488 diff::ComparisonOptions Options;
489 if (MaxSize != -1)
490 Options.MaxSize = MaxSize;
491 if (!StopAfter.empty()) {
492 if (StopAfter == "topdown")
493 Options.StopAfterTopDown = true;
494 else if (StopAfter != "bottomup") {
495 llvm::errs() << "Error: Invalid argument for -stop-after\n";
496 return 1;
497 }
498 }
499 diff::SyntaxTree SrcTree(Src->getASTContext());
500 diff::SyntaxTree DstTree(Dst->getASTContext());
501 diff::ASTDiff Diff(SrcTree, DstTree, Options);
502
503 if (HtmlDiff) {
504 llvm::outs() << HtmlDiffHeader << "<pre>";
505 llvm::outs() << "<div id='L' class='code'>";
506 printHtmlForNode(OS&: llvm::outs(), Diff, Tree&: SrcTree, IsLeft: true, Id: SrcTree.getRootId(), Offset: 0);
507 llvm::outs() << "</div>";
508 llvm::outs() << "<div id='R' class='code'>";
509 printHtmlForNode(OS&: llvm::outs(), Diff, Tree&: DstTree, IsLeft: false, Id: DstTree.getRootId(),
510 Offset: 0);
511 llvm::outs() << "</div>";
512 llvm::outs() << "</pre></div></body></html>\n";
513 return 0;
514 }
515
516 for (diff::NodeId Dst : DstTree) {
517 diff::NodeId Src = Diff.getMapped(SourceTree: DstTree, Id: Dst);
518 if (PrintMatches && Src.isValid()) {
519 llvm::outs() << "Match ";
520 printNode(OS&: llvm::outs(), Tree&: SrcTree, Id: Src);
521 llvm::outs() << " to ";
522 printNode(OS&: llvm::outs(), Tree&: DstTree, Id: Dst);
523 llvm::outs() << "\n";
524 }
525 printDstChange(OS&: llvm::outs(), Diff, SrcTree, DstTree, Dst);
526 }
527 for (diff::NodeId Src : SrcTree) {
528 if (Diff.getMapped(SourceTree: SrcTree, Id: Src).isInvalid()) {
529 llvm::outs() << "Delete ";
530 printNode(OS&: llvm::outs(), Tree&: SrcTree, Id: Src);
531 llvm::outs() << "\n";
532 }
533 }
534
535 return 0;
536}
537

source code of clang/tools/clang-diff/ClangDiff.cpp