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1 /*
2  * Copyright 2016 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #include "stdio.h"
9 #include "SkSLParser.h"
10 #include "ast/SkSLASTBinaryExpression.h"
11 #include "ast/SkSLASTBlock.h"
12 #include "ast/SkSLASTBoolLiteral.h"
13 #include "ast/SkSLASTBreakStatement.h"
14 #include "ast/SkSLASTCallSuffix.h"
15 #include "ast/SkSLASTContinueStatement.h"
16 #include "ast/SkSLASTDiscardStatement.h"
17 #include "ast/SkSLASTDoStatement.h"
18 #include "ast/SkSLASTEnum.h"
19 #include "ast/SkSLASTExpression.h"
20 #include "ast/SkSLASTExpressionStatement.h"
21 #include "ast/SkSLASTExtension.h"
22 #include "ast/SkSLASTFieldSuffix.h"
23 #include "ast/SkSLASTFloatLiteral.h"
24 #include "ast/SkSLASTForStatement.h"
25 #include "ast/SkSLASTFunction.h"
26 #include "ast/SkSLASTIdentifier.h"
27 #include "ast/SkSLASTIfStatement.h"
28 #include "ast/SkSLASTIndexSuffix.h"
29 #include "ast/SkSLASTInterfaceBlock.h"
30 #include "ast/SkSLASTIntLiteral.h"
31 #include "ast/SkSLASTModifiersDeclaration.h"
32 #include "ast/SkSLASTParameter.h"
33 #include "ast/SkSLASTPrefixExpression.h"
34 #include "ast/SkSLASTReturnStatement.h"
35 #include "ast/SkSLASTSection.h"
36 #include "ast/SkSLASTStatement.h"
37 #include "ast/SkSLASTSuffixExpression.h"
38 #include "ast/SkSLASTSwitchCase.h"
39 #include "ast/SkSLASTSwitchStatement.h"
40 #include "ast/SkSLASTTernaryExpression.h"
41 #include "ast/SkSLASTType.h"
42 #include "ast/SkSLASTVarDeclaration.h"
43 #include "ast/SkSLASTVarDeclarationStatement.h"
44 #include "ast/SkSLASTWhileStatement.h"
45 #include "ir/SkSLSymbolTable.h"
46 #include "ir/SkSLModifiers.h"
47 #include "ir/SkSLType.h"
48 
49 #ifndef SKSL_STANDALONE
50 #include "SkOnce.h"
51 #endif
52 
53 namespace SkSL {
54 
55 #define MAX_PARSE_DEPTH 50
56 
57 class AutoDepth {
58 public:
AutoDepth(Parser * p)59     AutoDepth(Parser* p)
60     : fParser(p) {
61         fParser->fDepth++;
62     }
63 
~AutoDepth()64     ~AutoDepth() {
65         fParser->fDepth--;
66     }
67 
checkValid()68     bool checkValid() {
69         if (fParser->fDepth > MAX_PARSE_DEPTH) {
70             fParser->error(fParser->peek(), String("exceeded max parse depth"));
71             return false;
72         }
73         return true;
74     }
75 
76 private:
77     Parser* fParser;
78 };
79 
80 std::unordered_map<String, Parser::LayoutToken>* Parser::layoutTokens;
81 
InitLayoutMap()82 void Parser::InitLayoutMap() {
83     layoutTokens = new std::unordered_map<String, LayoutToken>;
84     #define TOKEN(name, text) (*layoutTokens)[text] = LayoutToken::name
85     TOKEN(LOCATION,                     "location");
86     TOKEN(OFFSET,                       "offset");
87     TOKEN(BINDING,                      "binding");
88     TOKEN(INDEX,                        "index");
89     TOKEN(SET,                          "set");
90     TOKEN(BUILTIN,                      "builtin");
91     TOKEN(INPUT_ATTACHMENT_INDEX,       "input_attachment_index");
92     TOKEN(ORIGIN_UPPER_LEFT,            "origin_upper_left");
93     TOKEN(OVERRIDE_COVERAGE,            "override_coverage");
94     TOKEN(BLEND_SUPPORT_ALL_EQUATIONS,  "blend_support_all_equations");
95     TOKEN(BLEND_SUPPORT_MULTIPLY,       "blend_support_multiply");
96     TOKEN(BLEND_SUPPORT_SCREEN,         "blend_support_screen");
97     TOKEN(BLEND_SUPPORT_OVERLAY,        "blend_support_overlay");
98     TOKEN(BLEND_SUPPORT_DARKEN,         "blend_support_darken");
99     TOKEN(BLEND_SUPPORT_LIGHTEN,        "blend_support_lighten");
100     TOKEN(BLEND_SUPPORT_COLORDODGE,     "blend_support_colordodge");
101     TOKEN(BLEND_SUPPORT_COLORBURN,      "blend_support_colorburn");
102     TOKEN(BLEND_SUPPORT_HARDLIGHT,      "blend_support_hardlight");
103     TOKEN(BLEND_SUPPORT_SOFTLIGHT,      "blend_support_softlight");
104     TOKEN(BLEND_SUPPORT_DIFFERENCE,     "blend_support_difference");
105     TOKEN(BLEND_SUPPORT_EXCLUSION,      "blend_support_exclusion");
106     TOKEN(BLEND_SUPPORT_HSL_HUE,        "blend_support_hsl_hue");
107     TOKEN(BLEND_SUPPORT_HSL_SATURATION, "blend_support_hsl_saturation");
108     TOKEN(BLEND_SUPPORT_HSL_COLOR,      "blend_support_hsl_color");
109     TOKEN(BLEND_SUPPORT_HSL_LUMINOSITY, "blend_support_hsl_luminosity");
110     TOKEN(PUSH_CONSTANT,                "push_constant");
111     TOKEN(POINTS,                       "points");
112     TOKEN(LINES,                        "lines");
113     TOKEN(LINE_STRIP,                   "line_strip");
114     TOKEN(LINES_ADJACENCY,              "lines_adjacency");
115     TOKEN(TRIANGLES,                    "triangles");
116     TOKEN(TRIANGLE_STRIP,               "triangle_strip");
117     TOKEN(TRIANGLES_ADJACENCY,          "triangles_adjacency");
118     TOKEN(MAX_VERTICES,                 "max_vertices");
119     TOKEN(INVOCATIONS,                  "invocations");
120     TOKEN(WHEN,                         "when");
121     TOKEN(KEY,                          "key");
122     TOKEN(TRACKED,                      "tracked");
123     TOKEN(CTYPE,                        "ctype");
124     TOKEN(SKPMCOLOR4F,                  "SkPMColor4f");
125     TOKEN(SKRECT,                       "SkRect");
126     TOKEN(SKIRECT,                      "SkIRect");
127     TOKEN(SKPMCOLOR,                    "SkPMColor");
128     #undef TOKEN
129 }
130 
Parser(const char * text,size_t length,SymbolTable & types,ErrorReporter & errors)131 Parser::Parser(const char* text, size_t length, SymbolTable& types, ErrorReporter& errors)
132 : fText(text)
133 , fPushback(Token::INVALID, -1, -1)
134 , fTypes(types)
135 , fErrors(errors) {
136     fLexer.start(text, length);
137     static const bool layoutMapInitialized = []{ return (void)InitLayoutMap(), true; }();
138     (void) layoutMapInitialized;
139 }
140 
141 /* (directive | section | declaration)* END_OF_FILE */
file()142 std::vector<std::unique_ptr<ASTDeclaration>> Parser::file() {
143     std::vector<std::unique_ptr<ASTDeclaration>> result;
144     for (;;) {
145         switch (this->peek().fKind) {
146             case Token::END_OF_FILE:
147                 return result;
148             case Token::DIRECTIVE: {
149                 std::unique_ptr<ASTDeclaration> decl = this->directive();
150                 if (decl) {
151                     result.push_back(std::move(decl));
152                 }
153                 break;
154             }
155             case Token::SECTION: {
156                 std::unique_ptr<ASTDeclaration> section = this->section();
157                 if (section) {
158                     result.push_back(std::move(section));
159                 }
160                 break;
161             }
162             default: {
163                 std::unique_ptr<ASTDeclaration> decl = this->declaration();
164                 if (!decl) {
165                     continue;
166                 }
167                 result.push_back(std::move(decl));
168             }
169         }
170     }
171 }
172 
nextRawToken()173 Token Parser::nextRawToken() {
174     if (fPushback.fKind != Token::INVALID) {
175         Token result = fPushback;
176         fPushback.fKind = Token::INVALID;
177         return result;
178     }
179     Token result = fLexer.next();
180     return result;
181 }
182 
nextToken()183 Token Parser::nextToken() {
184     Token token = this->nextRawToken();
185     while (token.fKind == Token::WHITESPACE || token.fKind == Token::LINE_COMMENT ||
186            token.fKind == Token::BLOCK_COMMENT) {
187         token = this->nextRawToken();
188     }
189     return token;
190 }
191 
pushback(Token t)192 void Parser::pushback(Token t) {
193     SkASSERT(fPushback.fKind == Token::INVALID);
194     fPushback = std::move(t);
195 }
196 
peek()197 Token Parser::peek() {
198     if (fPushback.fKind == Token::INVALID) {
199         fPushback = this->nextToken();
200     }
201     return fPushback;
202 }
203 
checkNext(Token::Kind kind,Token * result)204 bool Parser::checkNext(Token::Kind kind, Token* result) {
205     if (fPushback.fKind != Token::INVALID && fPushback.fKind != kind) {
206         return false;
207     }
208     Token next = this->nextToken();
209     if (next.fKind == kind) {
210         if (result) {
211             *result = next;
212         }
213         return true;
214     }
215     this->pushback(std::move(next));
216     return false;
217 }
218 
expect(Token::Kind kind,const char * expected,Token * result)219 bool Parser::expect(Token::Kind kind, const char* expected, Token* result) {
220     Token next = this->nextToken();
221     if (next.fKind == kind) {
222         if (result) {
223             *result = std::move(next);
224         }
225         return true;
226     } else {
227         this->error(next, "expected " + String(expected) + ", but found '" +
228                     this->text(next) + "'");
229         return false;
230     }
231 }
232 
text(Token token)233 StringFragment Parser::text(Token token) {
234     return StringFragment(fText + token.fOffset, token.fLength);
235 }
236 
error(Token token,String msg)237 void Parser::error(Token token, String msg) {
238     this->error(token.fOffset, msg);
239 }
240 
error(int offset,String msg)241 void Parser::error(int offset, String msg) {
242     fErrors.error(offset, msg);
243 }
244 
isType(StringFragment name)245 bool Parser::isType(StringFragment name) {
246     return nullptr != fTypes[name];
247 }
248 
249 /* DIRECTIVE(#version) INT_LITERAL ("es" | "compatibility")? |
250    DIRECTIVE(#extension) IDENTIFIER COLON IDENTIFIER */
directive()251 std::unique_ptr<ASTDeclaration> Parser::directive() {
252     Token start;
253     if (!this->expect(Token::DIRECTIVE, "a directive", &start)) {
254         return nullptr;
255     }
256     StringFragment text = this->text(start);
257     if (text == "#version") {
258         this->expect(Token::INT_LITERAL, "a version number");
259         Token next = this->peek();
260         StringFragment nextText = this->text(next);
261         if (nextText == "es" || nextText == "compatibility") {
262             this->nextToken();
263         }
264         // version is ignored for now; it will eventually become an error when we stop pretending
265         // to be GLSL
266         return nullptr;
267     } else if (text == "#extension") {
268         Token name;
269         if (!this->expect(Token::IDENTIFIER, "an identifier", &name)) {
270             return nullptr;
271         }
272         if (!this->expect(Token::COLON, "':'")) {
273             return nullptr;
274         }
275         // FIXME: need to start paying attention to this token
276         if (!this->expect(Token::IDENTIFIER, "an identifier")) {
277             return nullptr;
278         }
279         return std::unique_ptr<ASTDeclaration>(new ASTExtension(start.fOffset,
280                                                                 String(this->text(name))));
281     } else {
282         this->error(start, "unsupported directive '" + this->text(start) + "'");
283         return nullptr;
284     }
285 }
286 
287 /* SECTION LBRACE (LPAREN IDENTIFIER RPAREN)? <any sequence of tokens with balanced braces>
288    RBRACE */
section()289 std::unique_ptr<ASTDeclaration> Parser::section() {
290     Token start;
291     if (!this->expect(Token::SECTION, "a section token", &start)) {
292         return nullptr;
293     }
294     String argument;
295     if (this->peek().fKind == Token::LPAREN) {
296         this->nextToken();
297         Token argToken;
298         if (!this->expect(Token::IDENTIFIER, "an identifier", &argToken)) {
299             return nullptr;
300         }
301         argument = this->text(argToken);
302         if (!this->expect(Token::RPAREN, "')'")) {
303             return nullptr;
304         }
305     }
306     if (!this->expect(Token::LBRACE, "'{'")) {
307         return nullptr;
308     }
309     String text;
310     int level = 1;
311     for (;;) {
312         Token next = this->nextRawToken();
313         switch (next.fKind) {
314             case Token::LBRACE:
315                 ++level;
316                 break;
317             case Token::RBRACE:
318                 --level;
319                 break;
320             case Token::END_OF_FILE:
321                 this->error(start, "reached end of file while parsing section");
322                 return nullptr;
323             default:
324                 break;
325         }
326         if (!level) {
327             break;
328         }
329         text += this->text(next);
330     }
331     StringFragment name = this->text(start);
332     ++name.fChars;
333     --name.fLength;
334     return std::unique_ptr<ASTDeclaration>(new ASTSection(start.fOffset,
335                                                           String(name),
336                                                           argument,
337                                                           text));
338 }
339 
340 /* ENUM CLASS IDENTIFIER LBRACE (IDENTIFIER (EQ expression)? (COMMA IDENTIFIER (EQ expression))*)?
341    RBRACE */
enumDeclaration()342 std::unique_ptr<ASTDeclaration> Parser::enumDeclaration() {
343     Token start;
344     if (!this->expect(Token::ENUM, "'enum'", &start)) {
345         return nullptr;
346     }
347     if (!this->expect(Token::CLASS, "'class'")) {
348         return nullptr;
349     }
350     Token name;
351     if (!this->expect(Token::IDENTIFIER, "an identifier", &name)) {
352         return nullptr;
353     }
354     if (!this->expect(Token::LBRACE, "'{'")) {
355         return nullptr;
356     }
357     fTypes.add(this->text(name), std::unique_ptr<Symbol>(new Type(this->text(name),
358                                                                   Type::kEnum_Kind)));
359     std::vector<StringFragment> names;
360     std::vector<std::unique_ptr<ASTExpression>> values;
361     if (!this->checkNext(Token::RBRACE)) {
362         Token id;
363         if (!this->expect(Token::IDENTIFIER, "an identifier", &id)) {
364             return nullptr;
365         }
366         names.push_back(this->text(id));
367         if (this->checkNext(Token::EQ)) {
368             std::unique_ptr<ASTExpression> value = this->assignmentExpression();
369             if (!value) {
370                 return nullptr;
371             }
372             values.push_back(std::move(value));
373         } else {
374             values.push_back(nullptr);
375         }
376         while (!this->checkNext(Token::RBRACE)) {
377             if (!this->expect(Token::COMMA, "','")) {
378                 return nullptr;
379             }
380             if (!this->expect(Token::IDENTIFIER, "an identifier", &id)) {
381                 return nullptr;
382             }
383             names.push_back(this->text(id));
384             if (this->checkNext(Token::EQ)) {
385                 std::unique_ptr<ASTExpression> value = this->assignmentExpression();
386                 if (!value) {
387                     return nullptr;
388                 }
389                 values.push_back(std::move(value));
390             } else {
391                 values.push_back(nullptr);
392             }
393         }
394     }
395     this->expect(Token::SEMICOLON, "';'");
396     return std::unique_ptr<ASTDeclaration>(new ASTEnum(name.fOffset, this->text(name), names,
397                                                        std::move(values)));
398 }
399 
400 /* enumDeclaration | modifiers (structVarDeclaration | type IDENTIFIER ((LPAREN parameter
401    (COMMA parameter)* RPAREN (block | SEMICOLON)) | SEMICOLON) | interfaceBlock) */
declaration()402 std::unique_ptr<ASTDeclaration> Parser::declaration() {
403     Token lookahead = this->peek();
404     if (lookahead.fKind == Token::ENUM) {
405         return this->enumDeclaration();
406     }
407     Modifiers modifiers = this->modifiers();
408     lookahead = this->peek();
409     if (lookahead.fKind == Token::IDENTIFIER && !this->isType(this->text(lookahead))) {
410         // we have an identifier that's not a type, could be the start of an interface block
411         return this->interfaceBlock(modifiers);
412     }
413     if (lookahead.fKind == Token::STRUCT) {
414         return this->structVarDeclaration(modifiers);
415     }
416     if (lookahead.fKind == Token::SEMICOLON) {
417         this->nextToken();
418         return std::unique_ptr<ASTDeclaration>(new ASTModifiersDeclaration(modifiers));
419     }
420     std::unique_ptr<ASTType> type(this->type());
421     if (!type) {
422         return nullptr;
423     }
424     if (type->fKind == ASTType::kStruct_Kind && this->checkNext(Token::SEMICOLON)) {
425         return nullptr;
426     }
427     Token name;
428     if (!this->expect(Token::IDENTIFIER, "an identifier", &name)) {
429         return nullptr;
430     }
431     if (this->checkNext(Token::LPAREN)) {
432         std::vector<std::unique_ptr<ASTParameter>> parameters;
433         while (this->peek().fKind != Token::RPAREN) {
434             if (parameters.size() > 0) {
435                 if (!this->expect(Token::COMMA, "','")) {
436                     return nullptr;
437                 }
438             }
439             std::unique_ptr<ASTParameter> parameter = this->parameter();
440             if (!parameter) {
441                 return nullptr;
442             }
443             parameters.push_back(std::move(parameter));
444         }
445         this->nextToken();
446         std::unique_ptr<ASTBlock> body;
447         if (!this->checkNext(Token::SEMICOLON)) {
448             body = this->block();
449             if (!body) {
450                 return nullptr;
451             }
452         }
453         return std::unique_ptr<ASTDeclaration>(new ASTFunction(name.fOffset,
454                                                                modifiers,
455                                                                std::move(type),
456                                                                this->text(name),
457                                                                std::move(parameters),
458                                                                std::move(body)));
459     } else {
460         return this->varDeclarationEnd(modifiers, std::move(type), this->text(name));
461     }
462 }
463 
464 /* modifiers type IDENTIFIER varDeclarationEnd */
varDeclarations()465 std::unique_ptr<ASTVarDeclarations> Parser::varDeclarations() {
466     Modifiers modifiers = this->modifiers();
467     std::unique_ptr<ASTType> type(this->type());
468     if (!type) {
469         return nullptr;
470     }
471     Token name;
472     if (!this->expect(Token::IDENTIFIER, "an identifier", &name)) {
473         return nullptr;
474     }
475     return this->varDeclarationEnd(modifiers, std::move(type), this->text(name));
476 }
477 
478 /* STRUCT IDENTIFIER LBRACE varDeclaration* RBRACE */
structDeclaration()479 std::unique_ptr<ASTType> Parser::structDeclaration() {
480     if (!this->expect(Token::STRUCT, "'struct'")) {
481         return nullptr;
482     }
483     Token name;
484     if (!this->expect(Token::IDENTIFIER, "an identifier", &name)) {
485         return nullptr;
486     }
487     if (!this->expect(Token::LBRACE, "'{'")) {
488         return nullptr;
489     }
490     std::vector<Type::Field> fields;
491     while (this->peek().fKind != Token::RBRACE) {
492         std::unique_ptr<ASTVarDeclarations> decl = this->varDeclarations();
493         if (!decl) {
494             return nullptr;
495         }
496         for (const auto& var : decl->fVars) {
497             auto type = (const Type*) fTypes[decl->fType->fName];
498             for (int i = (int) var.fSizes.size() - 1; i >= 0; i--) {
499                 if (!var.fSizes[i] || var.fSizes[i]->fKind != ASTExpression::kInt_Kind) {
500                     this->error(decl->fOffset, "array size in struct field must be a constant");
501                     return nullptr;
502                 }
503                 uint64_t columns = ((ASTIntLiteral&) *var.fSizes[i]).fValue;
504                 String name = type->name() + "[" + to_string(columns) + "]";
505                 type = new Type(name, Type::kArray_Kind, *type, (int) columns);
506                 fTypes.takeOwnership((Type*) type);
507             }
508             fields.push_back(Type::Field(decl->fModifiers, var.fName, type));
509             if (var.fValue) {
510                 this->error(decl->fOffset, "initializers are not permitted on struct fields");
511             }
512         }
513     }
514     if (!this->expect(Token::RBRACE, "'}'")) {
515         return nullptr;
516     }
517     fTypes.add(this->text(name), std::unique_ptr<Type>(new Type(name.fOffset, this->text(name),
518                                                                 fields)));
519     return std::unique_ptr<ASTType>(new ASTType(name.fOffset, this->text(name),
520                                                 ASTType::kStruct_Kind, std::vector<int>()));
521 }
522 
523 /* structDeclaration ((IDENTIFIER varDeclarationEnd) | SEMICOLON) */
structVarDeclaration(Modifiers modifiers)524 std::unique_ptr<ASTVarDeclarations> Parser::structVarDeclaration(Modifiers modifiers) {
525     std::unique_ptr<ASTType> type = this->structDeclaration();
526     if (!type) {
527         return nullptr;
528     }
529     Token name;
530     if (this->checkNext(Token::IDENTIFIER, &name)) {
531         std::unique_ptr<ASTVarDeclarations> result = this->varDeclarationEnd(modifiers,
532                                                                              std::move(type),
533                                                                              this->text(name));
534         if (result) {
535             for (const auto& var : result->fVars) {
536                 if (var.fValue) {
537                     this->error(var.fValue->fOffset,
538                                 "struct variables cannot be initialized");
539                 }
540             }
541         }
542         return result;
543     }
544     this->expect(Token::SEMICOLON, "';'");
545     return nullptr;
546 }
547 
548 /* (LBRACKET expression? RBRACKET)* (EQ assignmentExpression)? (COMMA IDENTIFER
549    (LBRACKET expression? RBRACKET)* (EQ assignmentExpression)?)* SEMICOLON */
varDeclarationEnd(Modifiers mods,std::unique_ptr<ASTType> type,StringFragment name)550 std::unique_ptr<ASTVarDeclarations> Parser::varDeclarationEnd(Modifiers mods,
551                                                               std::unique_ptr<ASTType> type,
552                                                               StringFragment name) {
553     std::vector<ASTVarDeclaration> vars;
554     std::vector<std::unique_ptr<ASTExpression>> currentVarSizes;
555     while (this->checkNext(Token::LBRACKET)) {
556         if (this->checkNext(Token::RBRACKET)) {
557             currentVarSizes.push_back(nullptr);
558         } else {
559             std::unique_ptr<ASTExpression> size(this->expression());
560             if (!size) {
561                 return nullptr;
562             }
563             currentVarSizes.push_back(std::move(size));
564             if (!this->expect(Token::RBRACKET, "']'")) {
565                 return nullptr;
566             }
567         }
568     }
569     std::unique_ptr<ASTExpression> value;
570     if (this->checkNext(Token::EQ)) {
571         value = this->assignmentExpression();
572         if (!value) {
573             return nullptr;
574         }
575     }
576     vars.emplace_back(name, std::move(currentVarSizes), std::move(value));
577     while (this->checkNext(Token::COMMA)) {
578         Token name;
579         if (!this->expect(Token::IDENTIFIER, "an identifier", &name)) {
580             return nullptr;
581         }
582         currentVarSizes.clear();
583         value.reset();
584         while (this->checkNext(Token::LBRACKET)) {
585             if (this->checkNext(Token::RBRACKET)) {
586                 currentVarSizes.push_back(nullptr);
587             } else {
588                 std::unique_ptr<ASTExpression> size(this->expression());
589                 if (!size) {
590                     return nullptr;
591                 }
592                 currentVarSizes.push_back(std::move(size));
593                 if (!this->expect(Token::RBRACKET, "']'")) {
594                     return nullptr;
595                 }
596             }
597         }
598         if (this->checkNext(Token::EQ)) {
599             value = this->assignmentExpression();
600             if (!value) {
601                 return nullptr;
602             }
603         }
604         vars.emplace_back(this->text(name), std::move(currentVarSizes), std::move(value));
605     }
606     if (!this->expect(Token::SEMICOLON, "';'")) {
607         return nullptr;
608     }
609     return std::unique_ptr<ASTVarDeclarations>(new ASTVarDeclarations(std::move(mods),
610                                                                       std::move(type),
611                                                                       std::move(vars)));
612 }
613 
614 /* modifiers type IDENTIFIER (LBRACKET INT_LITERAL RBRACKET)? */
parameter()615 std::unique_ptr<ASTParameter> Parser::parameter() {
616     Modifiers modifiers = this->modifiersWithDefaults(0);
617     std::unique_ptr<ASTType> type = this->type();
618     if (!type) {
619         return nullptr;
620     }
621     Token name;
622     if (!this->expect(Token::IDENTIFIER, "an identifier", &name)) {
623         return nullptr;
624     }
625     std::vector<int> sizes;
626     while (this->checkNext(Token::LBRACKET)) {
627         Token sizeToken;
628         if (!this->expect(Token::INT_LITERAL, "a positive integer", &sizeToken)) {
629             return nullptr;
630         }
631         sizes.push_back(SkSL::stoi(this->text(sizeToken)));
632         if (!this->expect(Token::RBRACKET, "']'")) {
633             return nullptr;
634         }
635     }
636     return std::unique_ptr<ASTParameter>(new ASTParameter(name.fOffset, modifiers, std::move(type),
637                                                           this->text(name), std::move(sizes)));
638 }
639 
640 /** EQ INT_LITERAL */
layoutInt()641 int Parser::layoutInt() {
642     if (!this->expect(Token::EQ, "'='")) {
643         return -1;
644     }
645     Token resultToken;
646     if (this->expect(Token::INT_LITERAL, "a non-negative integer", &resultToken)) {
647         return SkSL::stoi(this->text(resultToken));
648     }
649     return -1;
650 }
651 
652 /** EQ IDENTIFIER */
layoutIdentifier()653 StringFragment Parser::layoutIdentifier() {
654     if (!this->expect(Token::EQ, "'='")) {
655         return StringFragment();
656     }
657     Token resultToken;
658     if (!this->expect(Token::IDENTIFIER, "an identifier", &resultToken)) {
659         return StringFragment();
660     }
661     return this->text(resultToken);
662 }
663 
664 
665 /** EQ <any sequence of tokens with balanced parentheses and no top-level comma> */
layoutCode()666 String Parser::layoutCode() {
667     if (!this->expect(Token::EQ, "'='")) {
668         return "";
669     }
670     Token start = this->nextRawToken();
671     this->pushback(start);
672     String code;
673     int level = 1;
674     bool done = false;
675     while (!done) {
676         Token next = this->nextRawToken();
677         switch (next.fKind) {
678             case Token::LPAREN:
679                 ++level;
680                 break;
681             case Token::RPAREN:
682                 --level;
683                 break;
684             case Token::COMMA:
685                 if (level == 1) {
686                     done = true;
687                 }
688                 break;
689             case Token::END_OF_FILE:
690                 this->error(start, "reached end of file while parsing layout");
691                 return nullptr;
692             default:
693                 break;
694         }
695         if (!level) {
696             done = true;
697         }
698         if (done) {
699             this->pushback(std::move(next));
700         }
701         else {
702             code += this->text(next);
703         }
704     }
705     return code;
706 }
707 
708 /** (EQ IDENTIFIER('identity'))? */
layoutKey()709 Layout::Key Parser::layoutKey() {
710     if (this->peek().fKind == Token::EQ) {
711         this->expect(Token::EQ, "'='");
712         Token key;
713         if (this->expect(Token::IDENTIFIER, "an identifer", &key)) {
714             if (this->text(key) == "identity") {
715                 return Layout::kIdentity_Key;
716             } else {
717                 this->error(key, "unsupported layout key");
718             }
719         }
720     }
721     return Layout::kKey_Key;
722 }
723 
layoutCType()724 Layout::CType Parser::layoutCType() {
725     if (this->expect(Token::EQ, "'='")) {
726         Token t = this->nextToken();
727         String text = this->text(t);
728         auto found = layoutTokens->find(text);
729         if (found != layoutTokens->end()) {
730             switch (found->second) {
731                 case LayoutToken::SKPMCOLOR4F:
732                     return Layout::CType::kSkPMColor4f;
733                 case LayoutToken::SKRECT:
734                     return Layout::CType::kSkRect;
735                 case LayoutToken::SKIRECT:
736                     return Layout::CType::kSkIRect;
737                 case LayoutToken::SKPMCOLOR:
738                     return Layout::CType::kSkPMColor;
739                 default:
740                     break;
741             }
742         }
743         this->error(t, "unsupported ctype");
744     }
745     return Layout::CType::kDefault;
746 }
747 
748 /* LAYOUT LPAREN IDENTIFIER (EQ INT_LITERAL)? (COMMA IDENTIFIER (EQ INT_LITERAL)?)* RPAREN */
layout()749 Layout Parser::layout() {
750     int flags = 0;
751     int location = -1;
752     int offset = -1;
753     int binding = -1;
754     int index = -1;
755     int set = -1;
756     int builtin = -1;
757     int inputAttachmentIndex = -1;
758     Layout::Format format = Layout::Format::kUnspecified;
759     Layout::Primitive primitive = Layout::kUnspecified_Primitive;
760     int maxVertices = -1;
761     int invocations = -1;
762     String when;
763     Layout::Key key = Layout::kNo_Key;
764     Layout::CType ctype = Layout::CType::kDefault;
765     if (this->checkNext(Token::LAYOUT)) {
766         if (!this->expect(Token::LPAREN, "'('")) {
767             return Layout(flags, location, offset, binding, index, set, builtin,
768                           inputAttachmentIndex, format, primitive, maxVertices, invocations, when,
769                           key, ctype);
770         }
771         for (;;) {
772             Token t = this->nextToken();
773             String text = this->text(t);
774             auto found = layoutTokens->find(text);
775             if (found != layoutTokens->end()) {
776                 switch (found->second) {
777                     case LayoutToken::LOCATION:
778                         location = this->layoutInt();
779                         break;
780                     case LayoutToken::OFFSET:
781                         offset = this->layoutInt();
782                         break;
783                     case LayoutToken::BINDING:
784                         binding = this->layoutInt();
785                         break;
786                     case LayoutToken::INDEX:
787                         index = this->layoutInt();
788                         break;
789                     case LayoutToken::SET:
790                         set = this->layoutInt();
791                         break;
792                     case LayoutToken::BUILTIN:
793                         builtin = this->layoutInt();
794                         break;
795                     case LayoutToken::INPUT_ATTACHMENT_INDEX:
796                         inputAttachmentIndex = this->layoutInt();
797                         break;
798                     case LayoutToken::ORIGIN_UPPER_LEFT:
799                         flags |= Layout::kOriginUpperLeft_Flag;
800                         break;
801                     case LayoutToken::OVERRIDE_COVERAGE:
802                         flags |= Layout::kOverrideCoverage_Flag;
803                         break;
804                     case LayoutToken::BLEND_SUPPORT_ALL_EQUATIONS:
805                         flags |= Layout::kBlendSupportAllEquations_Flag;
806                         break;
807                     case LayoutToken::BLEND_SUPPORT_MULTIPLY:
808                         flags |= Layout::kBlendSupportMultiply_Flag;
809                         break;
810                     case LayoutToken::BLEND_SUPPORT_SCREEN:
811                         flags |= Layout::kBlendSupportScreen_Flag;
812                         break;
813                     case LayoutToken::BLEND_SUPPORT_OVERLAY:
814                         flags |= Layout::kBlendSupportOverlay_Flag;
815                         break;
816                     case LayoutToken::BLEND_SUPPORT_DARKEN:
817                         flags |= Layout::kBlendSupportDarken_Flag;
818                         break;
819                     case LayoutToken::BLEND_SUPPORT_LIGHTEN:
820                         flags |= Layout::kBlendSupportLighten_Flag;
821                         break;
822                     case LayoutToken::BLEND_SUPPORT_COLORDODGE:
823                         flags |= Layout::kBlendSupportColorDodge_Flag;
824                         break;
825                     case LayoutToken::BLEND_SUPPORT_COLORBURN:
826                         flags |= Layout::kBlendSupportColorBurn_Flag;
827                         break;
828                     case LayoutToken::BLEND_SUPPORT_HARDLIGHT:
829                         flags |= Layout::kBlendSupportHardLight_Flag;
830                         break;
831                     case LayoutToken::BLEND_SUPPORT_SOFTLIGHT:
832                         flags |= Layout::kBlendSupportSoftLight_Flag;
833                         break;
834                     case LayoutToken::BLEND_SUPPORT_DIFFERENCE:
835                         flags |= Layout::kBlendSupportDifference_Flag;
836                         break;
837                     case LayoutToken::BLEND_SUPPORT_EXCLUSION:
838                         flags |= Layout::kBlendSupportExclusion_Flag;
839                         break;
840                     case LayoutToken::BLEND_SUPPORT_HSL_HUE:
841                         flags |= Layout::kBlendSupportHSLHue_Flag;
842                         break;
843                     case LayoutToken::BLEND_SUPPORT_HSL_SATURATION:
844                         flags |= Layout::kBlendSupportHSLSaturation_Flag;
845                         break;
846                     case LayoutToken::BLEND_SUPPORT_HSL_COLOR:
847                         flags |= Layout::kBlendSupportHSLColor_Flag;
848                         break;
849                     case LayoutToken::BLEND_SUPPORT_HSL_LUMINOSITY:
850                         flags |= Layout::kBlendSupportHSLLuminosity_Flag;
851                         break;
852                     case LayoutToken::PUSH_CONSTANT:
853                         flags |= Layout::kPushConstant_Flag;
854                         break;
855                     case LayoutToken::TRACKED:
856                         flags |= Layout::kTracked_Flag;
857                         break;
858                     case LayoutToken::POINTS:
859                         primitive = Layout::kPoints_Primitive;
860                         break;
861                     case LayoutToken::LINES:
862                         primitive = Layout::kLines_Primitive;
863                         break;
864                     case LayoutToken::LINE_STRIP:
865                         primitive = Layout::kLineStrip_Primitive;
866                         break;
867                     case LayoutToken::LINES_ADJACENCY:
868                         primitive = Layout::kLinesAdjacency_Primitive;
869                         break;
870                     case LayoutToken::TRIANGLES:
871                         primitive = Layout::kTriangles_Primitive;
872                         break;
873                     case LayoutToken::TRIANGLE_STRIP:
874                         primitive = Layout::kTriangleStrip_Primitive;
875                         break;
876                     case LayoutToken::TRIANGLES_ADJACENCY:
877                         primitive = Layout::kTrianglesAdjacency_Primitive;
878                         break;
879                     case LayoutToken::MAX_VERTICES:
880                         maxVertices = this->layoutInt();
881                         break;
882                     case LayoutToken::INVOCATIONS:
883                         invocations = this->layoutInt();
884                         break;
885                     case LayoutToken::WHEN:
886                         when = this->layoutCode();
887                         break;
888                     case LayoutToken::KEY:
889                         key = this->layoutKey();
890                         break;
891                     case LayoutToken::CTYPE:
892                         ctype = this->layoutCType();
893                         break;
894                     default:
895                         this->error(t, ("'" + text + "' is not a valid layout qualifier").c_str());
896                         break;
897                 }
898             } else if (Layout::ReadFormat(text, &format)) {
899                // AST::ReadFormat stored the result in 'format'.
900             } else {
901                 this->error(t, ("'" + text + "' is not a valid layout qualifier").c_str());
902             }
903             if (this->checkNext(Token::RPAREN)) {
904                 break;
905             }
906             if (!this->expect(Token::COMMA, "','")) {
907                 break;
908             }
909         }
910     }
911     return Layout(flags, location, offset, binding, index, set, builtin, inputAttachmentIndex,
912                   format, primitive, maxVertices, invocations, when, key, ctype);
913 }
914 
915 /* layout? (UNIFORM | CONST | IN | OUT | INOUT | LOWP | MEDIUMP | HIGHP | FLAT | NOPERSPECTIVE |
916             READONLY | WRITEONLY | COHERENT | VOLATILE | RESTRICT | BUFFER | PLS | PLSIN |
917             PLSOUT)* */
modifiers()918 Modifiers Parser::modifiers() {
919     Layout layout = this->layout();
920     int flags = 0;
921     for (;;) {
922         // TODO: handle duplicate / incompatible flags
923         switch (peek().fKind) {
924             case Token::UNIFORM:
925                 this->nextToken();
926                 flags |= Modifiers::kUniform_Flag;
927                 break;
928             case Token::CONST:
929                 this->nextToken();
930                 flags |= Modifiers::kConst_Flag;
931                 break;
932             case Token::IN:
933                 this->nextToken();
934                 flags |= Modifiers::kIn_Flag;
935                 break;
936             case Token::OUT:
937                 this->nextToken();
938                 flags |= Modifiers::kOut_Flag;
939                 break;
940             case Token::INOUT:
941                 this->nextToken();
942                 flags |= Modifiers::kIn_Flag;
943                 flags |= Modifiers::kOut_Flag;
944                 break;
945             case Token::LOWP:
946                 this->nextToken();
947                 flags |= Modifiers::kLowp_Flag;
948                 break;
949             case Token::MEDIUMP:
950                 this->nextToken();
951                 flags |= Modifiers::kMediump_Flag;
952                 break;
953             case Token::HIGHP:
954                 this->nextToken();
955                 flags |= Modifiers::kHighp_Flag;
956                 break;
957             case Token::FLAT:
958                 this->nextToken();
959                 flags |= Modifiers::kFlat_Flag;
960                 break;
961             case Token::NOPERSPECTIVE:
962                 this->nextToken();
963                 flags |= Modifiers::kNoPerspective_Flag;
964                 break;
965             case Token::READONLY:
966                 this->nextToken();
967                 flags |= Modifiers::kReadOnly_Flag;
968                 break;
969             case Token::WRITEONLY:
970                 this->nextToken();
971                 flags |= Modifiers::kWriteOnly_Flag;
972                 break;
973             case Token::COHERENT:
974                 this->nextToken();
975                 flags |= Modifiers::kCoherent_Flag;
976                 break;
977             case Token::VOLATILE:
978                 this->nextToken();
979                 flags |= Modifiers::kVolatile_Flag;
980                 break;
981             case Token::RESTRICT:
982                 this->nextToken();
983                 flags |= Modifiers::kRestrict_Flag;
984                 break;
985             case Token::BUFFER:
986                 this->nextToken();
987                 flags |= Modifiers::kBuffer_Flag;
988                 break;
989             case Token::HASSIDEEFFECTS:
990                 this->nextToken();
991                 flags |= Modifiers::kHasSideEffects_Flag;
992                 break;
993             case Token::PLS:
994                 this->nextToken();
995                 flags |= Modifiers::kPLS_Flag;
996                 break;
997             case Token::PLSIN:
998                 this->nextToken();
999                 flags |= Modifiers::kPLSIn_Flag;
1000                 break;
1001             case Token::PLSOUT:
1002                 this->nextToken();
1003                 flags |= Modifiers::kPLSOut_Flag;
1004                 break;
1005             default:
1006                 return Modifiers(layout, flags);
1007         }
1008     }
1009 }
1010 
modifiersWithDefaults(int defaultFlags)1011 Modifiers Parser::modifiersWithDefaults(int defaultFlags) {
1012     Modifiers result = this->modifiers();
1013     if (!result.fFlags) {
1014         return Modifiers(result.fLayout, defaultFlags);
1015     }
1016     return result;
1017 }
1018 
1019 /* ifStatement | forStatement | doStatement | whileStatement | block | expression */
statement()1020 std::unique_ptr<ASTStatement> Parser::statement() {
1021     Token start = this->peek();
1022     switch (start.fKind) {
1023         case Token::IF: // fall through
1024         case Token::STATIC_IF:
1025             return this->ifStatement();
1026         case Token::FOR:
1027             return this->forStatement();
1028         case Token::DO:
1029             return this->doStatement();
1030         case Token::WHILE:
1031             return this->whileStatement();
1032         case Token::SWITCH: // fall through
1033         case Token::STATIC_SWITCH:
1034             return this->switchStatement();
1035         case Token::RETURN:
1036             return this->returnStatement();
1037         case Token::BREAK:
1038             return this->breakStatement();
1039         case Token::CONTINUE:
1040             return this->continueStatement();
1041         case Token::DISCARD:
1042             return this->discardStatement();
1043         case Token::LBRACE:
1044             return this->block();
1045         case Token::SEMICOLON:
1046             this->nextToken();
1047             return std::unique_ptr<ASTStatement>(new ASTBlock(start.fOffset,
1048                                                      std::vector<std::unique_ptr<ASTStatement>>()));
1049         case Token::CONST:   // fall through
1050         case Token::HIGHP:   // fall through
1051         case Token::MEDIUMP: // fall through
1052         case Token::LOWP: {
1053             auto decl = this->varDeclarations();
1054             if (!decl) {
1055                 return nullptr;
1056             }
1057             return std::unique_ptr<ASTStatement>(new ASTVarDeclarationStatement(std::move(decl)));
1058         }
1059         case Token::IDENTIFIER:
1060             if (this->isType(this->text(start))) {
1061                 auto decl = this->varDeclarations();
1062                 if (!decl) {
1063                     return nullptr;
1064                 }
1065                 return std::unique_ptr<ASTStatement>(new ASTVarDeclarationStatement(
1066                                                                                   std::move(decl)));
1067             }
1068             // fall through
1069         default:
1070             return this->expressionStatement();
1071     }
1072 }
1073 
1074 /* IDENTIFIER(type) (LBRACKET intLiteral? RBRACKET)* */
type()1075 std::unique_ptr<ASTType> Parser::type() {
1076     Token type;
1077     if (!this->expect(Token::IDENTIFIER, "a type", &type)) {
1078         return nullptr;
1079     }
1080     if (!this->isType(this->text(type))) {
1081         this->error(type, ("no type named '" + this->text(type) + "'").c_str());
1082         return nullptr;
1083     }
1084     std::vector<int> sizes;
1085     while (this->checkNext(Token::LBRACKET)) {
1086         if (this->peek().fKind != Token::RBRACKET) {
1087             int64_t i;
1088             if (this->intLiteral(&i)) {
1089                 sizes.push_back(i);
1090             } else {
1091                 return nullptr;
1092             }
1093         } else {
1094             sizes.push_back(-1);
1095         }
1096         this->expect(Token::RBRACKET, "']'");
1097     }
1098     return std::unique_ptr<ASTType>(new ASTType(type.fOffset, this->text(type),
1099                                                 ASTType::kIdentifier_Kind, sizes));
1100 }
1101 
1102 /* IDENTIFIER LBRACE varDeclaration* RBRACE (IDENTIFIER (LBRACKET expression? RBRACKET)*)? */
interfaceBlock(Modifiers mods)1103 std::unique_ptr<ASTDeclaration> Parser::interfaceBlock(Modifiers mods) {
1104     Token name;
1105     if (!this->expect(Token::IDENTIFIER, "an identifier", &name)) {
1106         return nullptr;
1107     }
1108     if (peek().fKind != Token::LBRACE) {
1109         // we only get into interfaceBlock if we found a top-level identifier which was not a type.
1110         // 99% of the time, the user was not actually intending to create an interface block, so
1111         // it's better to report it as an unknown type
1112         this->error(name, "no type named '" + this->text(name) + "'");
1113         return nullptr;
1114     }
1115     this->nextToken();
1116     std::vector<std::unique_ptr<ASTVarDeclarations>> decls;
1117     while (this->peek().fKind != Token::RBRACE) {
1118         std::unique_ptr<ASTVarDeclarations> decl = this->varDeclarations();
1119         if (!decl) {
1120             return nullptr;
1121         }
1122         decls.push_back(std::move(decl));
1123     }
1124     this->nextToken();
1125     std::vector<std::unique_ptr<ASTExpression>> sizes;
1126     StringFragment instanceName;
1127     Token instanceNameToken;
1128     if (this->checkNext(Token::IDENTIFIER, &instanceNameToken)) {
1129         while (this->checkNext(Token::LBRACKET)) {
1130             if (this->peek().fKind != Token::RBRACKET) {
1131                 std::unique_ptr<ASTExpression> size = this->expression();
1132                 if (!size) {
1133                     return nullptr;
1134                 }
1135                 sizes.push_back(std::move(size));
1136             } else {
1137                 sizes.push_back(nullptr);
1138             }
1139             this->expect(Token::RBRACKET, "']'");
1140         }
1141         instanceName = this->text(instanceNameToken);
1142     }
1143     this->expect(Token::SEMICOLON, "';'");
1144     return std::unique_ptr<ASTDeclaration>(new ASTInterfaceBlock(name.fOffset, mods,
1145                                                                  this->text(name),
1146                                                                  std::move(decls),
1147                                                                  instanceName,
1148                                                                  std::move(sizes)));
1149 }
1150 
1151 /* IF LPAREN expression RPAREN statement (ELSE statement)? */
ifStatement()1152 std::unique_ptr<ASTIfStatement> Parser::ifStatement() {
1153     Token start;
1154     bool isStatic = this->checkNext(Token::STATIC_IF, &start);
1155     if (!isStatic && !this->expect(Token::IF, "'if'", &start)) {
1156         return nullptr;
1157     }
1158     if (!this->expect(Token::LPAREN, "'('")) {
1159         return nullptr;
1160     }
1161     std::unique_ptr<ASTExpression> test(this->expression());
1162     if (!test) {
1163         return nullptr;
1164     }
1165     if (!this->expect(Token::RPAREN, "')'")) {
1166         return nullptr;
1167     }
1168     std::unique_ptr<ASTStatement> ifTrue(this->statement());
1169     if (!ifTrue) {
1170         return nullptr;
1171     }
1172     std::unique_ptr<ASTStatement> ifFalse;
1173     if (this->checkNext(Token::ELSE)) {
1174         ifFalse = this->statement();
1175         if (!ifFalse) {
1176             return nullptr;
1177         }
1178     }
1179     return std::unique_ptr<ASTIfStatement>(new ASTIfStatement(start.fOffset,
1180                                                               isStatic,
1181                                                               std::move(test),
1182                                                               std::move(ifTrue),
1183                                                               std::move(ifFalse)));
1184 }
1185 
1186 /* DO statement WHILE LPAREN expression RPAREN SEMICOLON */
doStatement()1187 std::unique_ptr<ASTDoStatement> Parser::doStatement() {
1188     Token start;
1189     if (!this->expect(Token::DO, "'do'", &start)) {
1190         return nullptr;
1191     }
1192     std::unique_ptr<ASTStatement> statement(this->statement());
1193     if (!statement) {
1194         return nullptr;
1195     }
1196     if (!this->expect(Token::WHILE, "'while'")) {
1197         return nullptr;
1198     }
1199     if (!this->expect(Token::LPAREN, "'('")) {
1200         return nullptr;
1201     }
1202     std::unique_ptr<ASTExpression> test(this->expression());
1203     if (!test) {
1204         return nullptr;
1205     }
1206     if (!this->expect(Token::RPAREN, "')'")) {
1207         return nullptr;
1208     }
1209     if (!this->expect(Token::SEMICOLON, "';'")) {
1210         return nullptr;
1211     }
1212     return std::unique_ptr<ASTDoStatement>(new ASTDoStatement(start.fOffset,
1213                                                               std::move(statement),
1214                                                               std::move(test)));
1215 }
1216 
1217 /* WHILE LPAREN expression RPAREN STATEMENT */
whileStatement()1218 std::unique_ptr<ASTWhileStatement> Parser::whileStatement() {
1219     Token start;
1220     if (!this->expect(Token::WHILE, "'while'", &start)) {
1221         return nullptr;
1222     }
1223     if (!this->expect(Token::LPAREN, "'('")) {
1224         return nullptr;
1225     }
1226     std::unique_ptr<ASTExpression> test(this->expression());
1227     if (!test) {
1228         return nullptr;
1229     }
1230     if (!this->expect(Token::RPAREN, "')'")) {
1231         return nullptr;
1232     }
1233     std::unique_ptr<ASTStatement> statement(this->statement());
1234     if (!statement) {
1235         return nullptr;
1236     }
1237     return std::unique_ptr<ASTWhileStatement>(new ASTWhileStatement(start.fOffset,
1238                                                                     std::move(test),
1239                                                                     std::move(statement)));
1240 }
1241 
1242 /* CASE expression COLON statement* */
switchCase()1243 std::unique_ptr<ASTSwitchCase> Parser::switchCase() {
1244     Token start;
1245     if (!this->expect(Token::CASE, "'case'", &start)) {
1246         return nullptr;
1247     }
1248     std::unique_ptr<ASTExpression> value = this->expression();
1249     if (!value) {
1250         return nullptr;
1251     }
1252     if (!this->expect(Token::COLON, "':'")) {
1253         return nullptr;
1254     }
1255     std::vector<std::unique_ptr<ASTStatement>> statements;
1256     while (this->peek().fKind != Token::RBRACE && this->peek().fKind != Token::CASE &&
1257            this->peek().fKind != Token::DEFAULT) {
1258         std::unique_ptr<ASTStatement> s = this->statement();
1259         if (!s) {
1260             return nullptr;
1261         }
1262         statements.push_back(std::move(s));
1263     }
1264     return std::unique_ptr<ASTSwitchCase>(new ASTSwitchCase(start.fOffset, std::move(value),
1265                                                             std::move(statements)));
1266 }
1267 
1268 /* SWITCH LPAREN expression RPAREN LBRACE switchCase* (DEFAULT COLON statement*)? RBRACE */
switchStatement()1269 std::unique_ptr<ASTStatement> Parser::switchStatement() {
1270     Token start;
1271     bool isStatic = this->checkNext(Token::STATIC_SWITCH, &start);
1272     if (!isStatic && !this->expect(Token::SWITCH, "'switch'", &start)) {
1273         return nullptr;
1274     }
1275     if (!this->expect(Token::LPAREN, "'('")) {
1276         return nullptr;
1277     }
1278     std::unique_ptr<ASTExpression> value(this->expression());
1279     if (!value) {
1280         return nullptr;
1281     }
1282     if (!this->expect(Token::RPAREN, "')'")) {
1283         return nullptr;
1284     }
1285     if (!this->expect(Token::LBRACE, "'{'")) {
1286         return nullptr;
1287     }
1288     std::vector<std::unique_ptr<ASTSwitchCase>> cases;
1289     while (this->peek().fKind == Token::CASE) {
1290         std::unique_ptr<ASTSwitchCase> c = this->switchCase();
1291         if (!c) {
1292             return nullptr;
1293         }
1294         cases.push_back(std::move(c));
1295     }
1296     // Requiring default: to be last (in defiance of C and GLSL) was a deliberate decision. Other
1297     // parts of the compiler may rely upon this assumption.
1298     if (this->peek().fKind == Token::DEFAULT) {
1299         Token defaultStart;
1300         SkAssertResult(this->expect(Token::DEFAULT, "'default'", &defaultStart));
1301         if (!this->expect(Token::COLON, "':'")) {
1302             return nullptr;
1303         }
1304         std::vector<std::unique_ptr<ASTStatement>> statements;
1305         while (this->peek().fKind != Token::RBRACE) {
1306             std::unique_ptr<ASTStatement> s = this->statement();
1307             if (!s) {
1308                 return nullptr;
1309             }
1310             statements.push_back(std::move(s));
1311         }
1312         cases.emplace_back(new ASTSwitchCase(defaultStart.fOffset, nullptr,
1313                                              std::move(statements)));
1314     }
1315     if (!this->expect(Token::RBRACE, "'}'")) {
1316         return nullptr;
1317     }
1318     return std::unique_ptr<ASTStatement>(new ASTSwitchStatement(start.fOffset,
1319                                                                 isStatic,
1320                                                                 std::move(value),
1321                                                                 std::move(cases)));
1322 }
1323 
1324 /* FOR LPAREN (declaration | expression)? SEMICOLON expression? SEMICOLON expression? RPAREN
1325    STATEMENT */
forStatement()1326 std::unique_ptr<ASTForStatement> Parser::forStatement() {
1327     Token start;
1328     if (!this->expect(Token::FOR, "'for'", &start)) {
1329         return nullptr;
1330     }
1331     if (!this->expect(Token::LPAREN, "'('")) {
1332         return nullptr;
1333     }
1334     std::unique_ptr<ASTStatement> initializer;
1335     Token nextToken = this->peek();
1336     switch (nextToken.fKind) {
1337         case Token::SEMICOLON:
1338             this->nextToken();
1339             break;
1340         case Token::CONST: {
1341             std::unique_ptr<ASTVarDeclarations> vd = this->varDeclarations();
1342             if (!vd) {
1343                 return nullptr;
1344             }
1345             initializer = std::unique_ptr<ASTStatement>(new ASTVarDeclarationStatement(
1346                                                                                     std::move(vd)));
1347             break;
1348         }
1349         case Token::IDENTIFIER: {
1350             if (this->isType(this->text(nextToken))) {
1351                 std::unique_ptr<ASTVarDeclarations> vd = this->varDeclarations();
1352                 if (!vd) {
1353                     return nullptr;
1354                 }
1355                 initializer = std::unique_ptr<ASTStatement>(new ASTVarDeclarationStatement(
1356                                                                                     std::move(vd)));
1357                 break;
1358             }
1359         } // fall through
1360         default:
1361             initializer = this->expressionStatement();
1362     }
1363     std::unique_ptr<ASTExpression> test;
1364     if (this->peek().fKind != Token::SEMICOLON) {
1365         test = this->expression();
1366         if (!test) {
1367             return nullptr;
1368         }
1369     }
1370     if (!this->expect(Token::SEMICOLON, "';'")) {
1371         return nullptr;
1372     }
1373     std::unique_ptr<ASTExpression> next;
1374     if (this->peek().fKind != Token::RPAREN) {
1375         next = this->expression();
1376         if (!next) {
1377             return nullptr;
1378         }
1379     }
1380     if (!this->expect(Token::RPAREN, "')'")) {
1381         return nullptr;
1382     }
1383     std::unique_ptr<ASTStatement> statement(this->statement());
1384     if (!statement) {
1385         return nullptr;
1386     }
1387     return std::unique_ptr<ASTForStatement>(new ASTForStatement(start.fOffset,
1388                                                                 std::move(initializer),
1389                                                                 std::move(test), std::move(next),
1390                                                                 std::move(statement)));
1391 }
1392 
1393 /* RETURN expression? SEMICOLON */
returnStatement()1394 std::unique_ptr<ASTReturnStatement> Parser::returnStatement() {
1395     Token start;
1396     if (!this->expect(Token::RETURN, "'return'", &start)) {
1397         return nullptr;
1398     }
1399     std::unique_ptr<ASTExpression> expression;
1400     if (this->peek().fKind != Token::SEMICOLON) {
1401         expression = this->expression();
1402         if (!expression) {
1403             return nullptr;
1404         }
1405     }
1406     if (!this->expect(Token::SEMICOLON, "';'")) {
1407         return nullptr;
1408     }
1409     return std::unique_ptr<ASTReturnStatement>(new ASTReturnStatement(start.fOffset,
1410                                                                       std::move(expression)));
1411 }
1412 
1413 /* BREAK SEMICOLON */
breakStatement()1414 std::unique_ptr<ASTBreakStatement> Parser::breakStatement() {
1415     Token start;
1416     if (!this->expect(Token::BREAK, "'break'", &start)) {
1417         return nullptr;
1418     }
1419     if (!this->expect(Token::SEMICOLON, "';'")) {
1420         return nullptr;
1421     }
1422     return std::unique_ptr<ASTBreakStatement>(new ASTBreakStatement(start.fOffset));
1423 }
1424 
1425 /* CONTINUE SEMICOLON */
continueStatement()1426 std::unique_ptr<ASTContinueStatement> Parser::continueStatement() {
1427     Token start;
1428     if (!this->expect(Token::CONTINUE, "'continue'", &start)) {
1429         return nullptr;
1430     }
1431     if (!this->expect(Token::SEMICOLON, "';'")) {
1432         return nullptr;
1433     }
1434     return std::unique_ptr<ASTContinueStatement>(new ASTContinueStatement(start.fOffset));
1435 }
1436 
1437 /* DISCARD SEMICOLON */
discardStatement()1438 std::unique_ptr<ASTDiscardStatement> Parser::discardStatement() {
1439     Token start;
1440     if (!this->expect(Token::DISCARD, "'continue'", &start)) {
1441         return nullptr;
1442     }
1443     if (!this->expect(Token::SEMICOLON, "';'")) {
1444         return nullptr;
1445     }
1446     return std::unique_ptr<ASTDiscardStatement>(new ASTDiscardStatement(start.fOffset));
1447 }
1448 
1449 /* LBRACE statement* RBRACE */
block()1450 std::unique_ptr<ASTBlock> Parser::block() {
1451     AutoDepth depth(this);
1452     if (!depth.checkValid()) {
1453         return nullptr;
1454     }
1455     Token start;
1456     if (!this->expect(Token::LBRACE, "'{'", &start)) {
1457         return nullptr;
1458     }
1459     std::vector<std::unique_ptr<ASTStatement>> statements;
1460     for (;;) {
1461         switch (this->peek().fKind) {
1462             case Token::RBRACE:
1463                 this->nextToken();
1464                 return std::unique_ptr<ASTBlock>(new ASTBlock(start.fOffset,
1465                                                               std::move(statements)));
1466             case Token::END_OF_FILE:
1467                 this->error(this->peek(), "expected '}', but found end of file");
1468                 return nullptr;
1469             default: {
1470                 std::unique_ptr<ASTStatement> statement = this->statement();
1471                 if (!statement) {
1472                     return nullptr;
1473                 }
1474                 statements.push_back(std::move(statement));
1475             }
1476         }
1477     }
1478 }
1479 
1480 /* expression SEMICOLON */
expressionStatement()1481 std::unique_ptr<ASTExpressionStatement> Parser::expressionStatement() {
1482     std::unique_ptr<ASTExpression> expr = this->expression();
1483     if (expr) {
1484         if (this->expect(Token::SEMICOLON, "';'")) {
1485             ASTExpressionStatement* result = new ASTExpressionStatement(std::move(expr));
1486             return std::unique_ptr<ASTExpressionStatement>(result);
1487         }
1488     }
1489     return nullptr;
1490 }
1491 
1492 /* commaExpression */
expression()1493 std::unique_ptr<ASTExpression> Parser::expression() {
1494     AutoDepth depth(this);
1495     if (!depth.checkValid()) {
1496         return nullptr;
1497     }
1498     return this->commaExpression();
1499 }
1500 
1501 /* assignmentExpression (COMMA assignmentExpression)* */
commaExpression()1502 std::unique_ptr<ASTExpression> Parser::commaExpression() {
1503     std::unique_ptr<ASTExpression> result = this->assignmentExpression();
1504     if (!result) {
1505         return nullptr;
1506     }
1507     Token t;
1508     while (this->checkNext(Token::COMMA, &t)) {
1509         std::unique_ptr<ASTExpression> right = this->commaExpression();
1510         if (!right) {
1511             return nullptr;
1512         }
1513         result.reset(new ASTBinaryExpression(std::move(result), std::move(t), std::move(right)));
1514     }
1515     return result;
1516 }
1517 
1518 /* ternaryExpression ((EQEQ | STAREQ | SLASHEQ | PERCENTEQ | PLUSEQ | MINUSEQ | SHLEQ | SHREQ |
1519    BITWISEANDEQ | BITWISEXOREQ | BITWISEOREQ | LOGICALANDEQ | LOGICALXOREQ | LOGICALOREQ)
1520    assignmentExpression)*
1521  */
assignmentExpression()1522 std::unique_ptr<ASTExpression> Parser::assignmentExpression() {
1523     std::unique_ptr<ASTExpression> result = this->ternaryExpression();
1524     if (!result) {
1525         return nullptr;
1526     }
1527     for (;;) {
1528         switch (this->peek().fKind) {
1529             case Token::EQ:           // fall through
1530             case Token::STAREQ:       // fall through
1531             case Token::SLASHEQ:      // fall through
1532             case Token::PERCENTEQ:    // fall through
1533             case Token::PLUSEQ:       // fall through
1534             case Token::MINUSEQ:      // fall through
1535             case Token::SHLEQ:        // fall through
1536             case Token::SHREQ:        // fall through
1537             case Token::BITWISEANDEQ: // fall through
1538             case Token::BITWISEXOREQ: // fall through
1539             case Token::BITWISEOREQ:  // fall through
1540             case Token::LOGICALANDEQ: // fall through
1541             case Token::LOGICALXOREQ: // fall through
1542             case Token::LOGICALOREQ: {
1543                 Token t = this->nextToken();
1544                 std::unique_ptr<ASTExpression> right = this->assignmentExpression();
1545                 if (!right) {
1546                     return nullptr;
1547                 }
1548                 result = std::unique_ptr<ASTExpression>(new ASTBinaryExpression(std::move(result),
1549                                                                                 std::move(t),
1550                                                                                 std::move(right)));
1551                 return result;
1552             }
1553             default:
1554                 return result;
1555         }
1556     }
1557 }
1558 
1559 /* logicalOrExpression ('?' expression ':' assignmentExpression)? */
ternaryExpression()1560 std::unique_ptr<ASTExpression> Parser::ternaryExpression() {
1561     std::unique_ptr<ASTExpression> result = this->logicalOrExpression();
1562     if (!result) {
1563         return nullptr;
1564     }
1565     if (this->checkNext(Token::QUESTION)) {
1566         std::unique_ptr<ASTExpression> trueExpr = this->expression();
1567         if (!trueExpr) {
1568             return nullptr;
1569         }
1570         if (this->expect(Token::COLON, "':'")) {
1571             std::unique_ptr<ASTExpression> falseExpr = this->assignmentExpression();
1572             return std::unique_ptr<ASTExpression>(new ASTTernaryExpression(std::move(result),
1573                                                                            std::move(trueExpr),
1574                                                                            std::move(falseExpr)));
1575         }
1576         return nullptr;
1577     }
1578     return result;
1579 }
1580 
1581 /* logicalXorExpression (LOGICALOR logicalXorExpression)* */
logicalOrExpression()1582 std::unique_ptr<ASTExpression> Parser::logicalOrExpression() {
1583     std::unique_ptr<ASTExpression> result = this->logicalXorExpression();
1584     if (!result) {
1585         return nullptr;
1586     }
1587     Token t;
1588     while (this->checkNext(Token::LOGICALOR, &t)) {
1589         std::unique_ptr<ASTExpression> right = this->logicalXorExpression();
1590         if (!right) {
1591             return nullptr;
1592         }
1593         result.reset(new ASTBinaryExpression(std::move(result), std::move(t), std::move(right)));
1594     }
1595     return result;
1596 }
1597 
1598 /* logicalAndExpression (LOGICALXOR logicalAndExpression)* */
logicalXorExpression()1599 std::unique_ptr<ASTExpression> Parser::logicalXorExpression() {
1600     std::unique_ptr<ASTExpression> result = this->logicalAndExpression();
1601     if (!result) {
1602         return nullptr;
1603     }
1604     Token t;
1605     while (this->checkNext(Token::LOGICALXOR, &t)) {
1606         std::unique_ptr<ASTExpression> right = this->logicalAndExpression();
1607         if (!right) {
1608             return nullptr;
1609         }
1610         result.reset(new ASTBinaryExpression(std::move(result), std::move(t), std::move(right)));
1611     }
1612     return result;
1613 }
1614 
1615 /* bitwiseOrExpression (LOGICALAND bitwiseOrExpression)* */
logicalAndExpression()1616 std::unique_ptr<ASTExpression> Parser::logicalAndExpression() {
1617     std::unique_ptr<ASTExpression> result = this->bitwiseOrExpression();
1618     if (!result) {
1619         return nullptr;
1620     }
1621     Token t;
1622     while (this->checkNext(Token::LOGICALAND, &t)) {
1623         std::unique_ptr<ASTExpression> right = this->bitwiseOrExpression();
1624         if (!right) {
1625             return nullptr;
1626         }
1627         result.reset(new ASTBinaryExpression(std::move(result), std::move(t), std::move(right)));
1628     }
1629     return result;
1630 }
1631 
1632 /* bitwiseXorExpression (BITWISEOR bitwiseXorExpression)* */
bitwiseOrExpression()1633 std::unique_ptr<ASTExpression> Parser::bitwiseOrExpression() {
1634     std::unique_ptr<ASTExpression> result = this->bitwiseXorExpression();
1635     if (!result) {
1636         return nullptr;
1637     }
1638     Token t;
1639     while (this->checkNext(Token::BITWISEOR, &t)) {
1640         std::unique_ptr<ASTExpression> right = this->bitwiseXorExpression();
1641         if (!right) {
1642             return nullptr;
1643         }
1644         result.reset(new ASTBinaryExpression(std::move(result), std::move(t), std::move(right)));
1645     }
1646     return result;
1647 }
1648 
1649 /* bitwiseAndExpression (BITWISEXOR bitwiseAndExpression)* */
bitwiseXorExpression()1650 std::unique_ptr<ASTExpression> Parser::bitwiseXorExpression() {
1651     std::unique_ptr<ASTExpression> result = this->bitwiseAndExpression();
1652     if (!result) {
1653         return nullptr;
1654     }
1655     Token t;
1656     while (this->checkNext(Token::BITWISEXOR, &t)) {
1657         std::unique_ptr<ASTExpression> right = this->bitwiseAndExpression();
1658         if (!right) {
1659             return nullptr;
1660         }
1661         result.reset(new ASTBinaryExpression(std::move(result), std::move(t), std::move(right)));
1662     }
1663     return result;
1664 }
1665 
1666 /* equalityExpression (BITWISEAND equalityExpression)* */
bitwiseAndExpression()1667 std::unique_ptr<ASTExpression> Parser::bitwiseAndExpression() {
1668     std::unique_ptr<ASTExpression> result = this->equalityExpression();
1669     if (!result) {
1670         return nullptr;
1671     }
1672     Token t;
1673     while (this->checkNext(Token::BITWISEAND, &t)) {
1674         std::unique_ptr<ASTExpression> right = this->equalityExpression();
1675         if (!right) {
1676             return nullptr;
1677         }
1678         result.reset(new ASTBinaryExpression(std::move(result), std::move(t), std::move(right)));
1679     }
1680     return result;
1681 }
1682 
1683 /* relationalExpression ((EQEQ | NEQ) relationalExpression)* */
equalityExpression()1684 std::unique_ptr<ASTExpression> Parser::equalityExpression() {
1685     std::unique_ptr<ASTExpression> result = this->relationalExpression();
1686     if (!result) {
1687         return nullptr;
1688     }
1689     for (;;) {
1690         switch (this->peek().fKind) {
1691             case Token::EQEQ:   // fall through
1692             case Token::NEQ: {
1693                 Token t = this->nextToken();
1694                 std::unique_ptr<ASTExpression> right = this->relationalExpression();
1695                 if (!right) {
1696                     return nullptr;
1697                 }
1698                 result.reset(new ASTBinaryExpression(std::move(result), std::move(t), std::move(right)));
1699                 break;
1700             }
1701             default:
1702                 return result;
1703         }
1704     }
1705 }
1706 
1707 /* shiftExpression ((LT | GT | LTEQ | GTEQ) shiftExpression)* */
relationalExpression()1708 std::unique_ptr<ASTExpression> Parser::relationalExpression() {
1709     std::unique_ptr<ASTExpression> result = this->shiftExpression();
1710     if (!result) {
1711         return nullptr;
1712     }
1713     for (;;) {
1714         switch (this->peek().fKind) {
1715             case Token::LT:   // fall through
1716             case Token::GT:   // fall through
1717             case Token::LTEQ: // fall through
1718             case Token::GTEQ: {
1719                 Token t = this->nextToken();
1720                 std::unique_ptr<ASTExpression> right = this->shiftExpression();
1721                 if (!right) {
1722                     return nullptr;
1723                 }
1724                 result.reset(new ASTBinaryExpression(std::move(result), std::move(t),
1725                                                      std::move(right)));
1726                 break;
1727             }
1728             default:
1729                 return result;
1730         }
1731     }
1732 }
1733 
1734 /* additiveExpression ((SHL | SHR) additiveExpression)* */
shiftExpression()1735 std::unique_ptr<ASTExpression> Parser::shiftExpression() {
1736     std::unique_ptr<ASTExpression> result = this->additiveExpression();
1737     if (!result) {
1738         return nullptr;
1739     }
1740     for (;;) {
1741         switch (this->peek().fKind) {
1742             case Token::SHL: // fall through
1743             case Token::SHR: {
1744                 Token t = this->nextToken();
1745                 std::unique_ptr<ASTExpression> right = this->additiveExpression();
1746                 if (!right) {
1747                     return nullptr;
1748                 }
1749                 result.reset(new ASTBinaryExpression(std::move(result), std::move(t),
1750                                                      std::move(right)));
1751                 break;
1752             }
1753             default:
1754                 return result;
1755         }
1756     }
1757 }
1758 
1759 /* multiplicativeExpression ((PLUS | MINUS) multiplicativeExpression)* */
additiveExpression()1760 std::unique_ptr<ASTExpression> Parser::additiveExpression() {
1761     std::unique_ptr<ASTExpression> result = this->multiplicativeExpression();
1762     if (!result) {
1763         return nullptr;
1764     }
1765     for (;;) {
1766         switch (this->peek().fKind) {
1767             case Token::PLUS: // fall through
1768             case Token::MINUS: {
1769                 Token t = this->nextToken();
1770                 std::unique_ptr<ASTExpression> right = this->multiplicativeExpression();
1771                 if (!right) {
1772                     return nullptr;
1773                 }
1774                 result.reset(new ASTBinaryExpression(std::move(result), std::move(t),
1775                                                      std::move(right)));
1776                 break;
1777             }
1778             default:
1779                 return result;
1780         }
1781     }
1782 }
1783 
1784 /* unaryExpression ((STAR | SLASH | PERCENT) unaryExpression)* */
multiplicativeExpression()1785 std::unique_ptr<ASTExpression> Parser::multiplicativeExpression() {
1786     std::unique_ptr<ASTExpression> result = this->unaryExpression();
1787     if (!result) {
1788         return nullptr;
1789     }
1790     for (;;) {
1791         switch (this->peek().fKind) {
1792             case Token::STAR: // fall through
1793             case Token::SLASH: // fall through
1794             case Token::PERCENT: {
1795                 Token t = this->nextToken();
1796                 std::unique_ptr<ASTExpression> right = this->unaryExpression();
1797                 if (!right) {
1798                     return nullptr;
1799                 }
1800                 result.reset(new ASTBinaryExpression(std::move(result), std::move(t),
1801                                                      std::move(right)));
1802                 break;
1803             }
1804             default:
1805                 return result;
1806         }
1807     }
1808 }
1809 
1810 /* postfixExpression | (PLUS | MINUS | NOT | PLUSPLUS | MINUSMINUS) unaryExpression */
unaryExpression()1811 std::unique_ptr<ASTExpression> Parser::unaryExpression() {
1812     switch (this->peek().fKind) {
1813         case Token::PLUS:       // fall through
1814         case Token::MINUS:      // fall through
1815         case Token::LOGICALNOT: // fall through
1816         case Token::BITWISENOT: // fall through
1817         case Token::PLUSPLUS:   // fall through
1818         case Token::MINUSMINUS: {
1819             Token t = this->nextToken();
1820             std::unique_ptr<ASTExpression> expr = this->unaryExpression();
1821             if (!expr) {
1822                 return nullptr;
1823             }
1824             return std::unique_ptr<ASTExpression>(new ASTPrefixExpression(std::move(t),
1825                                                                           std::move(expr)));
1826         }
1827         default:
1828             return this->postfixExpression();
1829     }
1830 }
1831 
1832 /* term suffix* */
postfixExpression()1833 std::unique_ptr<ASTExpression> Parser::postfixExpression() {
1834     std::unique_ptr<ASTExpression> result = this->term();
1835     if (!result) {
1836         return nullptr;
1837     }
1838     for (;;) {
1839         switch (this->peek().fKind) {
1840             case Token::LBRACKET:   // fall through
1841             case Token::DOT:        // fall through
1842             case Token::LPAREN:     // fall through
1843             case Token::PLUSPLUS:   // fall through
1844             case Token::MINUSMINUS: // fall through
1845             case Token::COLONCOLON: {
1846                 std::unique_ptr<ASTSuffix> s = this->suffix();
1847                 if (!s) {
1848                     return nullptr;
1849                 }
1850                 result.reset(new ASTSuffixExpression(std::move(result), std::move(s)));
1851                 break;
1852             }
1853             default:
1854                 return result;
1855         }
1856     }
1857 }
1858 
1859 /* LBRACKET expression? RBRACKET | DOT IDENTIFIER | LPAREN parameters RPAREN |
1860    PLUSPLUS | MINUSMINUS | COLONCOLON IDENTIFIER */
suffix()1861 std::unique_ptr<ASTSuffix> Parser::suffix() {
1862     Token next = this->nextToken();
1863     switch (next.fKind) {
1864         case Token::LBRACKET: {
1865             if (this->checkNext(Token::RBRACKET)) {
1866                 return std::unique_ptr<ASTSuffix>(new ASTIndexSuffix(next.fOffset));
1867             }
1868             std::unique_ptr<ASTExpression> e = this->expression();
1869             if (!e) {
1870                 return nullptr;
1871             }
1872             this->expect(Token::RBRACKET, "']' to complete array access expression");
1873             return std::unique_ptr<ASTSuffix>(new ASTIndexSuffix(std::move(e)));
1874         }
1875         case Token::DOT: // fall through
1876         case Token::COLONCOLON: {
1877             int offset = this->peek().fOffset;
1878             StringFragment text;
1879             if (this->identifier(&text)) {
1880                 return std::unique_ptr<ASTSuffix>(new ASTFieldSuffix(offset, std::move(text)));
1881             }
1882             return nullptr;
1883         }
1884         case Token::LPAREN: {
1885             std::vector<std::unique_ptr<ASTExpression>> parameters;
1886             if (this->peek().fKind != Token::RPAREN) {
1887                 for (;;) {
1888                     std::unique_ptr<ASTExpression> expr = this->assignmentExpression();
1889                     if (!expr) {
1890                         return nullptr;
1891                     }
1892                     parameters.push_back(std::move(expr));
1893                     if (!this->checkNext(Token::COMMA)) {
1894                         break;
1895                     }
1896                 }
1897             }
1898             this->expect(Token::RPAREN, "')' to complete function parameters");
1899             return std::unique_ptr<ASTSuffix>(new ASTCallSuffix(next.fOffset,
1900                                                                 std::move(parameters)));
1901         }
1902         case Token::PLUSPLUS:
1903             return std::unique_ptr<ASTSuffix>(new ASTSuffix(next.fOffset,
1904                                                             ASTSuffix::kPostIncrement_Kind));
1905         case Token::MINUSMINUS:
1906             return std::unique_ptr<ASTSuffix>(new ASTSuffix(next.fOffset,
1907                                                             ASTSuffix::kPostDecrement_Kind));
1908         default: {
1909             this->error(next,  "expected expression suffix, but found '" + this->text(next) +
1910                                          "'\n");
1911             return nullptr;
1912         }
1913     }
1914 }
1915 
1916 /* IDENTIFIER | intLiteral | floatLiteral | boolLiteral | '(' expression ')' */
term()1917 std::unique_ptr<ASTExpression> Parser::term() {
1918     std::unique_ptr<ASTExpression> result;
1919     Token t = this->peek();
1920     switch (t.fKind) {
1921         case Token::IDENTIFIER: {
1922             StringFragment text;
1923             if (this->identifier(&text)) {
1924                 result.reset(new ASTIdentifier(t.fOffset, std::move(text)));
1925             }
1926             break;
1927         }
1928         case Token::INT_LITERAL: {
1929             int64_t i;
1930             if (this->intLiteral(&i)) {
1931                 result.reset(new ASTIntLiteral(t.fOffset, i));
1932             }
1933             break;
1934         }
1935         case Token::FLOAT_LITERAL: {
1936             double f;
1937             if (this->floatLiteral(&f)) {
1938                 result.reset(new ASTFloatLiteral(t.fOffset, f));
1939             }
1940             break;
1941         }
1942         case Token::TRUE_LITERAL: // fall through
1943         case Token::FALSE_LITERAL: {
1944             bool b;
1945             if (this->boolLiteral(&b)) {
1946                 result.reset(new ASTBoolLiteral(t.fOffset, b));
1947             }
1948             break;
1949         }
1950         case Token::LPAREN: {
1951             this->nextToken();
1952             result = this->expression();
1953             if (result) {
1954                 this->expect(Token::RPAREN, "')' to complete expression");
1955             }
1956             break;
1957         }
1958         default:
1959             this->nextToken();
1960             this->error(t.fOffset,  "expected expression, but found '" + this->text(t) + "'\n");
1961             result = nullptr;
1962     }
1963     return result;
1964 }
1965 
1966 /* INT_LITERAL */
intLiteral(int64_t * dest)1967 bool Parser::intLiteral(int64_t* dest) {
1968     Token t;
1969     if (this->expect(Token::INT_LITERAL, "integer literal", &t)) {
1970         *dest = SkSL::stol(this->text(t));
1971         return true;
1972     }
1973     return false;
1974 }
1975 
1976 /* FLOAT_LITERAL */
floatLiteral(double * dest)1977 bool Parser::floatLiteral(double* dest) {
1978     Token t;
1979     if (this->expect(Token::FLOAT_LITERAL, "float literal", &t)) {
1980         *dest = SkSL::stod(this->text(t));
1981         return true;
1982     }
1983     return false;
1984 }
1985 
1986 /* TRUE_LITERAL | FALSE_LITERAL */
boolLiteral(bool * dest)1987 bool Parser::boolLiteral(bool* dest) {
1988     Token t = this->nextToken();
1989     switch (t.fKind) {
1990         case Token::TRUE_LITERAL:
1991             *dest = true;
1992             return true;
1993         case Token::FALSE_LITERAL:
1994             *dest = false;
1995             return true;
1996         default:
1997             this->error(t, "expected 'true' or 'false', but found '" + this->text(t) + "'\n");
1998             return false;
1999     }
2000 }
2001 
2002 /* IDENTIFIER */
identifier(StringFragment * dest)2003 bool Parser::identifier(StringFragment* dest) {
2004     Token t;
2005     if (this->expect(Token::IDENTIFIER, "identifier", &t)) {
2006         *dest = this->text(t);
2007         return true;
2008     }
2009     return false;
2010 }
2011 
2012 } // namespace
2013