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1 /*
2  * Copyright (C) 2019, The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "aidl_language.h"
18 #include "aidl_typenames.h"
19 #include "logging.h"
20 
21 #include <stdlib.h>
22 #include <algorithm>
23 #include <iostream>
24 #include <limits>
25 #include <memory>
26 
27 #include <android-base/parsedouble.h>
28 #include <android-base/parseint.h>
29 #include <android-base/strings.h>
30 
31 using android::base::ConsumeSuffix;
32 using android::base::EndsWith;
33 using android::base::Join;
34 using android::base::StartsWith;
35 using std::string;
36 using std::unique_ptr;
37 using std::vector;
38 
39 template <typename T>
CLZ(T x)40 constexpr int CLZ(T x) {
41   // __builtin_clz(0) is undefined
42   if (x == 0) return sizeof(T) * 8;
43   return (sizeof(T) == sizeof(uint64_t)) ? __builtin_clzl(x) : __builtin_clz(x);
44 }
45 
46 template <typename T>
47 class OverflowGuard {
48  public:
OverflowGuard(T value)49   OverflowGuard(T value) : mValue(value) {}
Overflowed() const50   bool Overflowed() const { return mOverflowed; }
51 
operator +()52   T operator+() { return +mValue; }
operator -()53   T operator-() {
54     if (isMin()) {
55       mOverflowed = true;
56       return 0;
57     }
58     return -mValue;
59   }
operator !()60   T operator!() { return !mValue; }
operator ~()61   T operator~() { return ~mValue; }
62 
operator +(T o)63   T operator+(T o) {
64     T out;
65     mOverflowed = __builtin_add_overflow(mValue, o, &out);
66     return out;
67   }
operator -(T o)68   T operator-(T o) {
69     T out;
70     mOverflowed = __builtin_sub_overflow(mValue, o, &out);
71     return out;
72   }
operator *(T o)73   T operator*(T o) {
74     T out;
75 #ifdef _WIN32
76     // ___mulodi4 not on windows https://bugs.llvm.org/show_bug.cgi?id=46669
77     // we should still get an error here from ubsan, but the nice error
78     // is needed on linux for aidl_parser_fuzzer, where we are more
79     // concerned about overflows elsewhere in the compiler in addition to
80     // those in interfaces.
81     out = mValue * o;
82 #else
83     mOverflowed = __builtin_mul_overflow(mValue, o, &out);
84 #endif
85     return out;
86   }
operator /(T o)87   T operator/(T o) {
88     if (o == 0 || (isMin() && o == -1)) {
89       mOverflowed = true;
90       return 0;
91     }
92     return static_cast<T>(mValue / o);
93   }
operator %(T o)94   T operator%(T o) {
95     if (o == 0 || (isMin() && o == -1)) {
96       mOverflowed = true;
97       return 0;
98     }
99     return static_cast<T>(mValue % o);
100   }
operator |(T o)101   T operator|(T o) { return mValue | o; }
operator ^(T o)102   T operator^(T o) { return mValue ^ o; }
operator &(T o)103   T operator&(T o) { return mValue & o; }
operator <(T o)104   T operator<(T o) { return mValue < o; }
operator >(T o)105   T operator>(T o) { return mValue > o; }
operator <=(T o)106   T operator<=(T o) { return mValue <= o; }
operator >=(T o)107   T operator>=(T o) { return mValue >= o; }
operator ==(T o)108   T operator==(T o) { return mValue == o; }
operator !=(T o)109   T operator!=(T o) { return mValue != o; }
operator >>(T o)110   T operator>>(T o) {
111     if (o < 0 || o >= static_cast<T>(sizeof(T) * 8) || mValue < 0) {
112       mOverflowed = true;
113       return 0;
114     }
115     return static_cast<T>(mValue >> o);
116   }
operator <<(T o)117   T operator<<(T o) {
118     if (o < 0 || mValue < 0 || o > CLZ(mValue) || o >= static_cast<T>(sizeof(T) * 8)) {
119       mOverflowed = true;
120       return 0;
121     }
122     return static_cast<T>(mValue << o);
123   }
operator ||(T o)124   T operator||(T o) { return mValue || o; }
operator &&(T o)125   T operator&&(T o) { return mValue && o; }
126 
127  private:
isMin()128   bool isMin() { return mValue == std::numeric_limits<T>::min(); }
129 
130   T mValue;
131   bool mOverflowed = false;
132 };
133 
134 template <typename T>
processGuard(const OverflowGuard<T> & guard,const AidlConstantValue & context)135 bool processGuard(const OverflowGuard<T>& guard, const AidlConstantValue& context) {
136   if (guard.Overflowed()) {
137     AIDL_ERROR(context) << "Constant expression computation overflows.";
138     return false;
139   }
140   return true;
141 }
142 
143 // TODO: factor out all these macros
144 #define SHOULD_NOT_REACH() AIDL_FATAL(AIDL_LOCATION_HERE) << "Should not reach."
145 #define OPEQ(__y__) (string(op_) == string(__y__))
146 #define COMPUTE_UNARY(T, __op__)         \
147   if (op == string(#__op__)) {           \
148     OverflowGuard<T> guard(val);         \
149     *out = __op__ guard;                 \
150     return processGuard(guard, context); \
151   }
152 #define COMPUTE_BINARY(T, __op__)        \
153   if (op == string(#__op__)) {           \
154     OverflowGuard<T> guard(lval);        \
155     *out = guard __op__ rval;            \
156     return processGuard(guard, context); \
157   }
158 #define OP_IS_BIN_ARITHMETIC (OPEQ("+") || OPEQ("-") || OPEQ("*") || OPEQ("/") || OPEQ("%"))
159 #define OP_IS_BIN_BITFLIP (OPEQ("|") || OPEQ("^") || OPEQ("&"))
160 #define OP_IS_BIN_COMP \
161   (OPEQ("<") || OPEQ(">") || OPEQ("<=") || OPEQ(">=") || OPEQ("==") || OPEQ("!="))
162 #define OP_IS_BIN_SHIFT (OPEQ(">>") || OPEQ("<<"))
163 #define OP_IS_BIN_LOGICAL (OPEQ("||") || OPEQ("&&"))
164 
165 // NOLINT to suppress missing parentheses warnings about __def__.
166 #define SWITCH_KIND(__cond__, __action__, __def__) \
167   switch (__cond__) {                              \
168     case Type::BOOLEAN:                            \
169       __action__(bool);                            \
170     case Type::INT8:                               \
171       __action__(int8_t);                          \
172     case Type::INT32:                              \
173       __action__(int32_t);                         \
174     case Type::INT64:                              \
175       __action__(int64_t);                         \
176     default:                                       \
177       __def__; /* NOLINT */                        \
178   }
179 
180 template <class T>
handleUnary(const AidlConstantValue & context,const string & op,T val,int64_t * out)181 bool handleUnary(const AidlConstantValue& context, const string& op, T val, int64_t* out) {
182   COMPUTE_UNARY(T, +)
183   COMPUTE_UNARY(T, -)
184   COMPUTE_UNARY(T, !)
185   COMPUTE_UNARY(T, ~)
186   AIDL_FATAL(context) << "Could not handleUnary for " << op << " " << val;
187   return false;
188 }
189 template <>
handleUnary(const AidlConstantValue & context,const string & op,bool val,int64_t * out)190 bool handleUnary<bool>(const AidlConstantValue& context, const string& op, bool val, int64_t* out) {
191   COMPUTE_UNARY(bool, +)
192   COMPUTE_UNARY(bool, -)
193   COMPUTE_UNARY(bool, !)
194 
195   if (op == "~") {
196     AIDL_ERROR(context) << "Bitwise negation of a boolean expression is always true.";
197     return false;
198   }
199   AIDL_FATAL(context) << "Could not handleUnary for " << op << " " << val;
200   return false;
201 }
202 
203 template <class T>
handleBinaryCommon(const AidlConstantValue & context,T lval,const string & op,T rval,int64_t * out)204 bool handleBinaryCommon(const AidlConstantValue& context, T lval, const string& op, T rval,
205                         int64_t* out) {
206   COMPUTE_BINARY(T, +)
207   COMPUTE_BINARY(T, -)
208   COMPUTE_BINARY(T, *)
209   COMPUTE_BINARY(T, /)
210   COMPUTE_BINARY(T, %)
211   COMPUTE_BINARY(T, |)
212   COMPUTE_BINARY(T, ^)
213   COMPUTE_BINARY(T, &)
214   // comparison operators: return 0 or 1 by nature.
215   COMPUTE_BINARY(T, ==)
216   COMPUTE_BINARY(T, !=)
217   COMPUTE_BINARY(T, <)
218   COMPUTE_BINARY(T, >)
219   COMPUTE_BINARY(T, <=)
220   COMPUTE_BINARY(T, >=)
221 
222   AIDL_FATAL(context) << "Could not handleBinaryCommon for " << lval << " " << op << " " << rval;
223   return false;
224 }
225 
226 template <class T>
handleShift(const AidlConstantValue & context,T lval,const string & op,T rval,int64_t * out)227 bool handleShift(const AidlConstantValue& context, T lval, const string& op, T rval, int64_t* out) {
228   // just cast rval to int64_t and it should fit.
229   COMPUTE_BINARY(T, >>)
230   COMPUTE_BINARY(T, <<)
231 
232   AIDL_FATAL(context) << "Could not handleShift for " << lval << " " << op << " " << rval;
233   return false;
234 }
235 
handleLogical(const AidlConstantValue & context,bool lval,const string & op,bool rval,int64_t * out)236 bool handleLogical(const AidlConstantValue& context, bool lval, const string& op, bool rval,
237                    int64_t* out) {
238   COMPUTE_BINARY(bool, ||);
239   COMPUTE_BINARY(bool, &&);
240 
241   AIDL_FATAL(context) << "Could not handleLogical for " << lval << " " << op << " " << rval;
242   return false;
243 }
244 
isValidLiteralChar(char c)245 static bool isValidLiteralChar(char c) {
246   return !(c <= 0x1f ||  // control characters are < 0x20
247            c >= 0x7f ||  // DEL is 0x7f
248            c == '\\');   // Disallow backslashes for future proofing.
249 }
250 
PrintCharLiteral(char c)251 static std::string PrintCharLiteral(char c) {
252   std::ostringstream os;
253   switch (c) {
254     case '\0':
255       os << "\\0";
256       break;
257     case '\'':
258       os << "\\'";
259       break;
260     case '\\':
261       os << "\\\\";
262       break;
263     case '\a':
264       os << "\\a";
265       break;
266     case '\b':
267       os << "\\b";
268       break;
269     case '\f':
270       os << "\\f";
271       break;
272     case '\n':
273       os << "\\n";
274       break;
275     case '\r':
276       os << "\\r";
277       break;
278     case '\t':
279       os << "\\t";
280       break;
281     case '\v':
282       os << "\\v";
283       break;
284     default:
285       if (std::isprint(static_cast<unsigned char>(c))) {
286         os << c;
287       } else {
288         os << "\\x" << std::hex << std::uppercase << static_cast<int>(c);
289       }
290   }
291   return os.str();
292 }
293 
ParseFloating(std::string_view sv,double * parsed)294 bool ParseFloating(std::string_view sv, double* parsed) {
295   // float literal should be parsed successfully.
296   android::base::ConsumeSuffix(&sv, "f");
297   return android::base::ParseDouble(std::string(sv).data(), parsed);
298 }
299 
ParseFloating(std::string_view sv,float * parsed)300 bool ParseFloating(std::string_view sv, float* parsed) {
301   // we only care about float literal (with suffix "f").
302   if (!android::base::ConsumeSuffix(&sv, "f")) {
303     return false;
304   }
305   return android::base::ParseFloat(std::string(sv).data(), parsed);
306 }
307 
IsCompatibleType(Type type,const string & op)308 bool AidlUnaryConstExpression::IsCompatibleType(Type type, const string& op) {
309   // Verify the unary type here
310   switch (type) {
311     case Type::BOOLEAN:  // fall-through
312     case Type::INT8:     // fall-through
313     case Type::INT32:    // fall-through
314     case Type::INT64:
315       return true;
316     case Type::FLOATING:
317       return (op == "+" || op == "-");
318     default:
319       return false;
320   }
321 }
322 
AreCompatibleTypes(Type t1,Type t2)323 bool AidlBinaryConstExpression::AreCompatibleTypes(Type t1, Type t2) {
324   switch (t1) {
325     case Type::ARRAY:
326       if (t2 == Type::ARRAY) {
327         return true;
328       }
329       break;
330     case Type::STRING:
331       if (t2 == Type::STRING) {
332         return true;
333       }
334       break;
335     case Type::BOOLEAN:  // fall-through
336     case Type::INT8:     // fall-through
337     case Type::INT32:    // fall-through
338     case Type::INT64:
339       switch (t2) {
340         case Type::BOOLEAN:  // fall-through
341         case Type::INT8:     // fall-through
342         case Type::INT32:    // fall-through
343         case Type::INT64:
344           return true;
345           break;
346         default:
347           break;
348       }
349       break;
350     default:
351       break;
352   }
353 
354   return false;
355 }
356 
357 // Returns the promoted kind for both operands
UsualArithmeticConversion(Type left,Type right)358 AidlConstantValue::Type AidlBinaryConstExpression::UsualArithmeticConversion(Type left,
359                                                                              Type right) {
360   // These are handled as special cases
361   AIDL_FATAL_IF(left == Type::STRING || right == Type::STRING, AIDL_LOCATION_HERE);
362   AIDL_FATAL_IF(left == Type::FLOATING || right == Type::FLOATING, AIDL_LOCATION_HERE);
363 
364   // Kinds in concern: bool, (u)int[8|32|64]
365   if (left == right) return left;  // easy case
366   if (left == Type::BOOLEAN) return right;
367   if (right == Type::BOOLEAN) return left;
368 
369   return left < right ? right : left;
370 }
371 
372 // Returns the promoted integral type where INT32 is the smallest type
IntegralPromotion(Type in)373 AidlConstantValue::Type AidlBinaryConstExpression::IntegralPromotion(Type in) {
374   return (Type::INT32 < in) ? in : Type::INT32;
375 }
376 
Default(const AidlTypeSpecifier & specifier)377 AidlConstantValue* AidlConstantValue::Default(const AidlTypeSpecifier& specifier) {
378   AidlLocation location = specifier.GetLocation();
379 
380   // allocation of int[0] is a bit wasteful in Java
381   if (specifier.IsArray()) {
382     return nullptr;
383   }
384 
385   const std::string name = specifier.GetName();
386   if (name == "boolean") {
387     return Boolean(location, false);
388   }
389   if (name == "char") {
390     return Character(location, "'\\0'");  // literal to be used in backends
391   }
392   if (name == "byte" || name == "int" || name == "long") {
393     return Integral(location, "0");
394   }
395   if (name == "float") {
396     return Floating(location, "0.0f");
397   }
398   if (name == "double") {
399     return Floating(location, "0.0");
400   }
401   return nullptr;
402 }
403 
Boolean(const AidlLocation & location,bool value)404 AidlConstantValue* AidlConstantValue::Boolean(const AidlLocation& location, bool value) {
405   return new AidlConstantValue(location, Type::BOOLEAN, value ? "true" : "false");
406 }
407 
Character(const AidlLocation & location,const std::string & value)408 AidlConstantValue* AidlConstantValue::Character(const AidlLocation& location,
409                                                 const std::string& value) {
410   static const char* kZeroString = "'\\0'";
411 
412   // We should have better supports for escapes in the future, but for now
413   // allow only what is needed for defaults.
414   if (value != kZeroString) {
415     AIDL_FATAL_IF(value.size() != 3 || value[0] != '\'' || value[2] != '\'', location) << value;
416 
417     if (!isValidLiteralChar(value[1])) {
418       AIDL_ERROR(location) << "Invalid character literal " << PrintCharLiteral(value[1]);
419       return new AidlConstantValue(location, Type::ERROR, value);
420     }
421   }
422 
423   return new AidlConstantValue(location, Type::CHARACTER, value);
424 }
425 
Floating(const AidlLocation & location,const std::string & value)426 AidlConstantValue* AidlConstantValue::Floating(const AidlLocation& location,
427                                                const std::string& value) {
428   return new AidlConstantValue(location, Type::FLOATING, value);
429 }
430 
IsHex(const string & value)431 bool AidlConstantValue::IsHex(const string& value) {
432   return StartsWith(value, "0x") || StartsWith(value, "0X");
433 }
434 
ParseIntegral(const string & value,int64_t * parsed_value,Type * parsed_type)435 bool AidlConstantValue::ParseIntegral(const string& value, int64_t* parsed_value,
436                                       Type* parsed_type) {
437   if (parsed_value == nullptr || parsed_type == nullptr) {
438     return false;
439   }
440 
441   std::string_view value_view = value;
442   const bool is_byte = ConsumeSuffix(&value_view, "u8");
443   const bool is_long = ConsumeSuffix(&value_view, "l") || ConsumeSuffix(&value_view, "L");
444   const std::string value_substr = std::string(value_view);
445 
446   *parsed_value = 0;
447   *parsed_type = Type::ERROR;
448 
449   if (is_byte && is_long) return false;
450 
451   if (IsHex(value)) {
452     // AIDL considers 'const int foo = 0xffffffff' as -1, but if we want to
453     // handle that when computing constant expressions, then we need to
454     // represent 0xffffffff as a uint32_t. However, AIDL only has signed types;
455     // so we parse as an unsigned int when possible and then cast to a signed
456     // int. One example of this is in ICameraService.aidl where a constant int
457     // is used for bit manipulations which ideally should be handled with an
458     // unsigned int.
459     //
460     // Note, for historical consistency, we need to consider small hex values
461     // as an integral type. Recognizing them as INT8 could break some files,
462     // even though it would simplify this code.
463     if (is_byte) {
464       uint8_t raw_value8;
465       if (!android::base::ParseUint<uint8_t>(value_substr, &raw_value8)) {
466         return false;
467       }
468       *parsed_value = static_cast<int8_t>(raw_value8);
469       *parsed_type = Type::INT8;
470     } else if (uint32_t raw_value32;
471                !is_long && android::base::ParseUint<uint32_t>(value_substr, &raw_value32)) {
472       *parsed_value = static_cast<int32_t>(raw_value32);
473       *parsed_type = Type::INT32;
474     } else if (uint64_t raw_value64;
475                android::base::ParseUint<uint64_t>(value_substr, &raw_value64)) {
476       *parsed_value = static_cast<int64_t>(raw_value64);
477       *parsed_type = Type::INT64;
478     } else {
479       return false;
480     }
481     return true;
482   }
483 
484   if (!android::base::ParseInt<int64_t>(value_substr, parsed_value)) {
485     return false;
486   }
487 
488   if (is_byte) {
489     if (*parsed_value > UINT8_MAX || *parsed_value < 0) {
490       return false;
491     }
492     *parsed_value = static_cast<int8_t>(*parsed_value);
493     *parsed_type = Type::INT8;
494   } else if (is_long) {
495     *parsed_type = Type::INT64;
496   } else {
497     // guess literal type.
498     if (*parsed_value <= INT8_MAX && *parsed_value >= INT8_MIN) {
499       *parsed_type = Type::INT8;
500     } else if (*parsed_value <= INT32_MAX && *parsed_value >= INT32_MIN) {
501       *parsed_type = Type::INT32;
502     } else {
503       *parsed_type = Type::INT64;
504     }
505   }
506   return true;
507 }
508 
Integral(const AidlLocation & location,const string & value)509 AidlConstantValue* AidlConstantValue::Integral(const AidlLocation& location, const string& value) {
510   AIDL_FATAL_IF(value.empty(), location);
511 
512   Type parsed_type;
513   int64_t parsed_value = 0;
514   bool success = ParseIntegral(value, &parsed_value, &parsed_type);
515   if (!success) {
516     return nullptr;
517   }
518 
519   return new AidlConstantValue(location, parsed_type, parsed_value, value);
520 }
521 
Array(const AidlLocation & location,std::unique_ptr<vector<unique_ptr<AidlConstantValue>>> values)522 AidlConstantValue* AidlConstantValue::Array(
523     const AidlLocation& location, std::unique_ptr<vector<unique_ptr<AidlConstantValue>>> values) {
524   AIDL_FATAL_IF(values == nullptr, location);
525   // Reconstruct literal value
526   std::vector<std::string> str_values;
527   for (const auto& v : *values) {
528     str_values.push_back(v->value_);
529   }
530   return new AidlConstantValue(location, Type::ARRAY, std::move(values),
531                                "{" + Join(str_values, ", ") + "}");
532 }
533 
String(const AidlLocation & location,const string & value)534 AidlConstantValue* AidlConstantValue::String(const AidlLocation& location, const string& value) {
535   AIDL_FATAL_IF(value.size() == 0, "If this is unquoted, we need to update the index log");
536   AIDL_FATAL_IF(value[0] != '\"', "If this is unquoted, we need to update the index log");
537 
538   for (size_t i = 0; i < value.length(); ++i) {
539     if (!isValidLiteralChar(value[i])) {
540       AIDL_ERROR(location) << "Found invalid character '" << value[i] << "' at index " << i - 1
541                            << " in string constant '" << value << "'";
542       return new AidlConstantValue(location, Type::ERROR, value);
543     }
544   }
545 
546   return new AidlConstantValue(location, Type::STRING, value);
547 }
548 
ValueString(const AidlTypeSpecifier & type,const ConstantValueDecorator & decorator) const549 string AidlConstantValue::ValueString(const AidlTypeSpecifier& type,
550                                       const ConstantValueDecorator& decorator) const {
551   if (type.IsGeneric()) {
552     AIDL_ERROR(type) << "Generic type cannot be specified with a constant literal.";
553     return "";
554   }
555   if (!is_evaluated_) {
556     // TODO(b/142722772) CheckValid() should be called before ValueString()
557     bool success = CheckValid();
558     success &= evaluate();
559     if (!success) {
560       // the detailed error message shall be printed in evaluate
561       return "";
562     }
563   }
564   if (!is_valid_) {
565     AIDL_ERROR(this) << "Invalid constant value: " + value_;
566     return "";
567   }
568 
569   const AidlDefinedType* defined_type = type.GetDefinedType();
570   if (defined_type && final_type_ != Type::ARRAY) {
571     const AidlEnumDeclaration* enum_type = defined_type->AsEnumDeclaration();
572     if (!enum_type) {
573       AIDL_ERROR(this) << "Invalid type (" << defined_type->GetCanonicalName()
574                        << ") for a const value (" << value_ << ")";
575       return "";
576     }
577     if (type_ != Type::REF) {
578       AIDL_ERROR(this) << "Invalid value (" << value_ << ") for enum "
579                        << enum_type->GetCanonicalName();
580       return "";
581     }
582     return decorator(type, value_);
583   }
584 
585   const string& type_string = type.Signature();
586   int err = 0;
587 
588   switch (final_type_) {
589     case Type::CHARACTER:
590       if (type_string == "char") {
591         return decorator(type, final_string_value_);
592       }
593       err = -1;
594       break;
595     case Type::STRING:
596       if (type_string == "String") {
597         return decorator(type, final_string_value_);
598       }
599       err = -1;
600       break;
601     case Type::BOOLEAN:  // fall-through
602     case Type::INT8:     // fall-through
603     case Type::INT32:    // fall-through
604     case Type::INT64:
605       if (type_string == "byte") {
606         if (final_value_ > INT8_MAX || final_value_ < INT8_MIN) {
607           err = -1;
608           break;
609         }
610         return decorator(type, std::to_string(static_cast<int8_t>(final_value_)));
611       } else if (type_string == "int") {
612         if (final_value_ > INT32_MAX || final_value_ < INT32_MIN) {
613           err = -1;
614           break;
615         }
616         return decorator(type, std::to_string(static_cast<int32_t>(final_value_)));
617       } else if (type_string == "long") {
618         return decorator(type, std::to_string(final_value_));
619       } else if (type_string == "boolean") {
620         return decorator(type, final_value_ ? "true" : "false");
621       }
622       err = -1;
623       break;
624     case Type::ARRAY: {
625       if (!type.IsArray()) {
626         err = -1;
627         break;
628       }
629       vector<string> value_strings;
630       value_strings.reserve(values_.size());
631       bool success = true;
632 
633       for (const auto& value : values_) {
634         string value_string;
635         type.ViewAsArrayBase([&](const auto& base_type) {
636           value_string = value->ValueString(base_type, decorator);
637         });
638         if (value_string.empty()) {
639           success = false;
640           break;
641         }
642         value_strings.push_back(value_string);
643       }
644       if (!success) {
645         err = -1;
646         break;
647       }
648       if (type.IsFixedSizeArray()) {
649         auto size =
650             std::get<FixedSizeArray>(type.GetArray()).dimensions.front()->EvaluatedValue<int32_t>();
651         if (values_.size() != static_cast<size_t>(size)) {
652           AIDL_ERROR(this) << "Expected an array of " << size << " elements, but found one with "
653                            << values_.size() << " elements";
654           err = -1;
655           break;
656         }
657       }
658       return decorator(type, value_strings);
659     }
660     case Type::FLOATING: {
661       if (type_string == "double") {
662         double parsed_value;
663         if (!ParseFloating(value_, &parsed_value)) {
664           AIDL_ERROR(this) << "Could not parse " << value_;
665           err = -1;
666           break;
667         }
668         return decorator(type, std::to_string(parsed_value));
669       }
670       if (type_string == "float") {
671         float parsed_value;
672         if (!ParseFloating(value_, &parsed_value)) {
673           AIDL_ERROR(this) << "Could not parse " << value_;
674           err = -1;
675           break;
676         }
677         return decorator(type, std::to_string(parsed_value) + "f");
678       }
679       err = -1;
680       break;
681     }
682     default:
683       err = -1;
684       break;
685   }
686 
687   AIDL_FATAL_IF(err == 0, this);
688   AIDL_ERROR(this) << "Invalid type specifier for " << ToString(final_type_) << ": " << type_string
689                    << " (" << value_ << ")";
690   return "";
691 }
692 
CheckValid() const693 bool AidlConstantValue::CheckValid() const {
694   // Nothing needs to be checked here. The constant value will be validated in
695   // the constructor or in the evaluate() function.
696   if (is_evaluated_) return is_valid_;
697 
698   switch (type_) {
699     case Type::BOOLEAN:    // fall-through
700     case Type::INT8:       // fall-through
701     case Type::INT32:      // fall-through
702     case Type::INT64:      // fall-through
703     case Type::CHARACTER:  // fall-through
704     case Type::STRING:     // fall-through
705     case Type::REF:        // fall-through
706     case Type::FLOATING:   // fall-through
707     case Type::UNARY:      // fall-through
708     case Type::BINARY:
709       is_valid_ = true;
710       break;
711     case Type::ARRAY:
712       is_valid_ = true;
713       for (const auto& v : values_) is_valid_ &= v->CheckValid();
714       break;
715     case Type::ERROR:
716       return false;
717     default:
718       AIDL_FATAL(this) << "Unrecognized constant value type: " << ToString(type_);
719       return false;
720   }
721 
722   return true;
723 }
724 
Evaluate() const725 bool AidlConstantValue::Evaluate() const {
726   if (CheckValid()) {
727     return evaluate();
728   } else {
729     return false;
730   }
731 }
732 
evaluate() const733 bool AidlConstantValue::evaluate() const {
734   if (is_evaluated_) {
735     return is_valid_;
736   }
737   int err = 0;
738   is_evaluated_ = true;
739 
740   switch (type_) {
741     case Type::ARRAY: {
742       Type array_type = Type::ERROR;
743       bool success = true;
744       for (const auto& value : values_) {
745         success = value->CheckValid();
746         if (success) {
747           success = value->evaluate();
748           if (!success) {
749             AIDL_ERROR(this) << "Invalid array element: " << value->value_;
750             break;
751           }
752           if (array_type == Type::ERROR) {
753             array_type = value->final_type_;
754           } else if (!AidlBinaryConstExpression::AreCompatibleTypes(array_type,
755                                                                     value->final_type_)) {
756             AIDL_ERROR(this) << "Incompatible array element type: " << ToString(value->final_type_)
757                              << ". Expecting type compatible with " << ToString(array_type);
758             success = false;
759             break;
760           }
761         } else {
762           break;
763         }
764       }
765       if (!success) {
766         err = -1;
767         break;
768       }
769       final_type_ = type_;
770       break;
771     }
772     case Type::BOOLEAN:
773       if ((value_ != "true") && (value_ != "false")) {
774         AIDL_ERROR(this) << "Invalid constant boolean value: " << value_;
775         err = -1;
776         break;
777       }
778       final_value_ = (value_ == "true") ? 1 : 0;
779       final_type_ = type_;
780       break;
781     case Type::INT8:   // fall-through
782     case Type::INT32:  // fall-through
783     case Type::INT64:
784       // Parsing happens in the constructor
785       final_type_ = type_;
786       break;
787     case Type::CHARACTER:  // fall-through
788     case Type::STRING:
789       final_string_value_ = value_;
790       final_type_ = type_;
791       break;
792     case Type::FLOATING:
793       // Just parse on the fly in ValueString
794       final_type_ = type_;
795       break;
796     default:
797       AIDL_FATAL(this) << "Unrecognized constant value type: " << ToString(type_);
798       err = -1;
799   }
800 
801   return (err == 0) ? true : false;
802 }
803 
ToString(Type type)804 string AidlConstantValue::ToString(Type type) {
805   switch (type) {
806     case Type::BOOLEAN:
807       return "a literal boolean";
808     case Type::INT8:
809       return "an int8 literal";
810     case Type::INT32:
811       return "an int32 literal";
812     case Type::INT64:
813       return "an int64 literal";
814     case Type::ARRAY:
815       return "a literal array";
816     case Type::CHARACTER:
817       return "a literal char";
818     case Type::STRING:
819       return "a literal string";
820     case Type::REF:
821       return "a reference";
822     case Type::FLOATING:
823       return "a literal float";
824     case Type::UNARY:
825       return "a unary expression";
826     case Type::BINARY:
827       return "a binary expression";
828     case Type::ERROR:
829       AIDL_FATAL(AIDL_LOCATION_HERE) << "aidl internal error: error type failed to halt program";
830       return "";
831     default:
832       AIDL_FATAL(AIDL_LOCATION_HERE)
833           << "aidl internal error: unknown constant type: " << static_cast<int>(type);
834       return "";  // not reached
835   }
836 }
837 
AidlConstantReference(const AidlLocation & location,const std::string & value)838 AidlConstantReference::AidlConstantReference(const AidlLocation& location, const std::string& value)
839     : AidlConstantValue(location, Type::REF, value) {
840   const auto pos = value.find_last_of('.');
841   if (pos == string::npos) {
842     field_name_ = value;
843   } else {
844     ref_type_ = std::make_unique<AidlTypeSpecifier>(location, value.substr(0, pos),
845                                                     /*array=*/std::nullopt, /*type_params=*/nullptr,
846                                                     Comments{});
847     field_name_ = value.substr(pos + 1);
848   }
849 }
850 
Resolve(const AidlDefinedType * scope) const851 const AidlConstantValue* AidlConstantReference::Resolve(const AidlDefinedType* scope) const {
852   if (resolved_) return resolved_;
853 
854   const AidlDefinedType* defined_type;
855   if (ref_type_) {
856     defined_type = ref_type_->GetDefinedType();
857   } else {
858     defined_type = scope;
859   }
860 
861   if (!defined_type) {
862     // This can happen when "const reference" is used in an unsupported way,
863     // but missed in checks there. It works as a safety net.
864     AIDL_ERROR(*this) << "Can't resolve the reference (" << value_ << ")";
865     return nullptr;
866   }
867 
868   if (auto enum_decl = defined_type->AsEnumDeclaration(); enum_decl) {
869     for (const auto& e : enum_decl->GetEnumerators()) {
870       if (e->GetName() == field_name_) {
871         return resolved_ = e->GetValue();
872       }
873     }
874   } else {
875     for (const auto& c : defined_type->GetConstantDeclarations()) {
876       if (c->GetName() == field_name_) {
877         return resolved_ = &c->GetValue();
878       }
879     }
880   }
881   AIDL_ERROR(*this) << "Can't find " << field_name_ << " in " << defined_type->GetName();
882   return nullptr;
883 }
884 
CheckValid() const885 bool AidlConstantReference::CheckValid() const {
886   if (is_evaluated_) return is_valid_;
887   AIDL_FATAL_IF(!resolved_, this) << "Should be resolved first: " << value_;
888   is_valid_ = resolved_->CheckValid();
889   return is_valid_;
890 }
891 
evaluate() const892 bool AidlConstantReference::evaluate() const {
893   if (is_evaluated_) return is_valid_;
894   AIDL_FATAL_IF(!resolved_, this) << "Should be resolved first: " << value_;
895   is_evaluated_ = true;
896 
897   resolved_->evaluate();
898   is_valid_ = resolved_->is_valid_;
899   final_type_ = resolved_->final_type_;
900   if (is_valid_) {
901     if (final_type_ == Type::STRING) {
902       final_string_value_ = resolved_->final_string_value_;
903     } else {
904       final_value_ = resolved_->final_value_;
905     }
906   }
907   return is_valid_;
908 }
909 
CheckValid() const910 bool AidlUnaryConstExpression::CheckValid() const {
911   if (is_evaluated_) return is_valid_;
912   AIDL_FATAL_IF(unary_ == nullptr, this);
913 
914   is_valid_ = unary_->CheckValid();
915   if (!is_valid_) {
916     final_type_ = Type::ERROR;
917     return false;
918   }
919 
920   return AidlConstantValue::CheckValid();
921 }
922 
evaluate() const923 bool AidlUnaryConstExpression::evaluate() const {
924   if (is_evaluated_) {
925     return is_valid_;
926   }
927   is_evaluated_ = true;
928 
929   // Recursively evaluate the expression tree
930   if (!unary_->is_evaluated_) {
931     // TODO(b/142722772) CheckValid() should be called before ValueString()
932     bool success = CheckValid();
933     success &= unary_->evaluate();
934     if (!success) {
935       is_valid_ = false;
936       return false;
937     }
938   }
939   if (!IsCompatibleType(unary_->final_type_, op_)) {
940     AIDL_ERROR(unary_) << "'" << op_ << "'"
941                        << " is not compatible with " << ToString(unary_->final_type_)
942                        << ": " + value_;
943     is_valid_ = false;
944     return false;
945   }
946   if (!unary_->is_valid_) {
947     AIDL_ERROR(unary_) << "Invalid constant unary expression: " + value_;
948     is_valid_ = false;
949     return false;
950   }
951   final_type_ = unary_->final_type_;
952 
953   if (final_type_ == Type::FLOATING) {
954     // don't do anything here. ValueString() will handle everything.
955     is_valid_ = true;
956     return true;
957   }
958 
959 #define CASE_UNARY(__type__) \
960   return is_valid_ =         \
961              handleUnary(*this, op_, static_cast<__type__>(unary_->final_value_), &final_value_);
962 
963   SWITCH_KIND(final_type_, CASE_UNARY, SHOULD_NOT_REACH(); final_type_ = Type::ERROR;
964               is_valid_ = false; return false;)
965 }
966 
CheckValid() const967 bool AidlBinaryConstExpression::CheckValid() const {
968   bool success = false;
969   if (is_evaluated_) return is_valid_;
970   AIDL_FATAL_IF(left_val_ == nullptr, this);
971   AIDL_FATAL_IF(right_val_ == nullptr, this);
972 
973   success = left_val_->CheckValid();
974   if (!success) {
975     final_type_ = Type::ERROR;
976     AIDL_ERROR(this) << "Invalid left operand in binary expression: " + value_;
977   }
978 
979   success = right_val_->CheckValid();
980   if (!success) {
981     AIDL_ERROR(this) << "Invalid right operand in binary expression: " + value_;
982     final_type_ = Type::ERROR;
983   }
984 
985   if (final_type_ == Type::ERROR) {
986     is_valid_ = false;
987     return false;
988   }
989 
990   is_valid_ = true;
991   return AidlConstantValue::CheckValid();
992 }
993 
evaluate() const994 bool AidlBinaryConstExpression::evaluate() const {
995   if (is_evaluated_) {
996     return is_valid_;
997   }
998   is_evaluated_ = true;
999   AIDL_FATAL_IF(left_val_ == nullptr, this);
1000   AIDL_FATAL_IF(right_val_ == nullptr, this);
1001 
1002   // Recursively evaluate the binary expression tree
1003   if (!left_val_->is_evaluated_ || !right_val_->is_evaluated_) {
1004     // TODO(b/142722772) CheckValid() should be called before ValueString()
1005     bool success = CheckValid();
1006     success &= left_val_->evaluate();
1007     success &= right_val_->evaluate();
1008     if (!success) {
1009       is_valid_ = false;
1010       return false;
1011     }
1012   }
1013   if (!left_val_->is_valid_ || !right_val_->is_valid_) {
1014     is_valid_ = false;
1015     return false;
1016   }
1017   is_valid_ = AreCompatibleTypes(left_val_->final_type_, right_val_->final_type_);
1018   if (!is_valid_) {
1019     AIDL_ERROR(this) << "Cannot perform operation '" << op_ << "' on "
1020                      << ToString(right_val_->GetType()) << " and " << ToString(left_val_->GetType())
1021                      << ".";
1022     return false;
1023   }
1024 
1025   bool isArithmeticOrBitflip = OP_IS_BIN_ARITHMETIC || OP_IS_BIN_BITFLIP;
1026 
1027   // Handle String case first
1028   if (left_val_->final_type_ == Type::STRING) {
1029     AIDL_FATAL_IF(right_val_->final_type_ != Type::STRING, this);
1030     if (!OPEQ("+")) {
1031       AIDL_ERROR(this) << "Only '+' is supported for strings, not '" << op_ << "'.";
1032       final_type_ = Type::ERROR;
1033       is_valid_ = false;
1034       return false;
1035     }
1036 
1037     // Remove trailing " from lhs
1038     const string& lhs = left_val_->final_string_value_;
1039     if (lhs.back() != '"') {
1040       AIDL_ERROR(this) << "'" << lhs << "' is missing a trailing quote.";
1041       final_type_ = Type::ERROR;
1042       is_valid_ = false;
1043       return false;
1044     }
1045     const string& rhs = right_val_->final_string_value_;
1046     // Remove starting " from rhs
1047     if (rhs.front() != '"') {
1048       AIDL_ERROR(this) << "'" << rhs << "' is missing a leading quote.";
1049       final_type_ = Type::ERROR;
1050       is_valid_ = false;
1051       return false;
1052     }
1053 
1054     final_string_value_ = string(lhs.begin(), lhs.end() - 1).append(rhs.begin() + 1, rhs.end());
1055     final_type_ = Type::STRING;
1056     return true;
1057   }
1058 
1059   // CASE: + - *  / % | ^ & < > <= >= == !=
1060   if (isArithmeticOrBitflip || OP_IS_BIN_COMP) {
1061     // promoted kind for both operands.
1062     Type promoted = UsualArithmeticConversion(IntegralPromotion(left_val_->final_type_),
1063                                               IntegralPromotion(right_val_->final_type_));
1064     // result kind.
1065     final_type_ = isArithmeticOrBitflip
1066                       ? promoted        // arithmetic or bitflip operators generates promoted type
1067                       : Type::BOOLEAN;  // comparison operators generates bool
1068 
1069 #define CASE_BINARY_COMMON(__type__)                                                        \
1070   return is_valid_ =                                                                        \
1071              handleBinaryCommon(*this, static_cast<__type__>(left_val_->final_value_), op_, \
1072                                 static_cast<__type__>(right_val_->final_value_), &final_value_);
1073 
1074     SWITCH_KIND(promoted, CASE_BINARY_COMMON, SHOULD_NOT_REACH(); final_type_ = Type::ERROR;
1075                 is_valid_ = false; return false;)
1076   }
1077 
1078   // CASE: << >>
1079   string newOp = op_;
1080   if (OP_IS_BIN_SHIFT) {
1081     // promoted kind for both operands.
1082     final_type_ = UsualArithmeticConversion(IntegralPromotion(left_val_->final_type_),
1083                                             IntegralPromotion(right_val_->final_type_));
1084     auto numBits = right_val_->final_value_;
1085     if (numBits < 0) {
1086       // shifting with negative number of bits is undefined in C. In AIDL it
1087       // is defined as shifting into the other direction.
1088       newOp = OPEQ("<<") ? ">>" : "<<";
1089       numBits = -numBits;
1090     }
1091 
1092 #define CASE_SHIFT(__type__)                                                                   \
1093   return is_valid_ = handleShift(*this, static_cast<__type__>(left_val_->final_value_), newOp, \
1094                                  static_cast<__type__>(numBits), &final_value_);
1095 
1096     SWITCH_KIND(final_type_, CASE_SHIFT, SHOULD_NOT_REACH(); final_type_ = Type::ERROR;
1097                 is_valid_ = false; return false;)
1098   }
1099 
1100   // CASE: && ||
1101   if (OP_IS_BIN_LOGICAL) {
1102     final_type_ = Type::BOOLEAN;
1103     // easy; everything is bool.
1104     return handleLogical(*this, left_val_->final_value_, op_, right_val_->final_value_,
1105                          &final_value_);
1106   }
1107 
1108   SHOULD_NOT_REACH();
1109   is_valid_ = false;
1110   return false;
1111 }
1112 
1113 // Constructor for integer(byte, int, long)
1114 // Keep parsed integer & literal
AidlConstantValue(const AidlLocation & location,Type parsed_type,int64_t parsed_value,const string & checked_value)1115 AidlConstantValue::AidlConstantValue(const AidlLocation& location, Type parsed_type,
1116                                      int64_t parsed_value, const string& checked_value)
1117     : AidlNode(location),
1118       type_(parsed_type),
1119       value_(checked_value),
1120       final_type_(parsed_type),
1121       final_value_(parsed_value) {
1122   AIDL_FATAL_IF(value_.empty() && type_ != Type::ERROR, location);
1123   AIDL_FATAL_IF(type_ != Type::INT8 && type_ != Type::INT32 && type_ != Type::INT64, location);
1124 }
1125 
1126 // Constructor for non-integer(String, char, boolean, float, double)
1127 // Keep literal as it is. (e.g. String literal has double quotes at both ends)
AidlConstantValue(const AidlLocation & location,Type type,const string & checked_value)1128 AidlConstantValue::AidlConstantValue(const AidlLocation& location, Type type,
1129                                      const string& checked_value)
1130     : AidlNode(location),
1131       type_(type),
1132       value_(checked_value),
1133       final_type_(type) {
1134   AIDL_FATAL_IF(value_.empty() && type_ != Type::ERROR, location);
1135   switch (type_) {
1136     case Type::INT8:
1137     case Type::INT32:
1138     case Type::INT64:
1139     case Type::ARRAY:
1140       AIDL_FATAL(this) << "Invalid type: " << ToString(type_);
1141       break;
1142     default:
1143       break;
1144   }
1145 }
1146 
1147 // Constructor for array
AidlConstantValue(const AidlLocation & location,Type type,std::unique_ptr<vector<unique_ptr<AidlConstantValue>>> values,const std::string & value)1148 AidlConstantValue::AidlConstantValue(const AidlLocation& location, Type type,
1149                                      std::unique_ptr<vector<unique_ptr<AidlConstantValue>>> values,
1150                                      const std::string& value)
1151     : AidlNode(location),
1152       type_(type),
1153       values_(std::move(*values)),
1154       value_(value),
1155       is_valid_(false),
1156       is_evaluated_(false),
1157       final_type_(type) {
1158   AIDL_FATAL_IF(type_ != Type::ARRAY, location);
1159 }
1160 
AidlUnaryConstExpression(const AidlLocation & location,const string & op,std::unique_ptr<AidlConstantValue> rval)1161 AidlUnaryConstExpression::AidlUnaryConstExpression(const AidlLocation& location, const string& op,
1162                                                    std::unique_ptr<AidlConstantValue> rval)
1163     : AidlConstantValue(location, Type::UNARY, op + rval->value_),
1164       unary_(std::move(rval)),
1165       op_(op) {
1166   final_type_ = Type::UNARY;
1167 }
1168 
AidlBinaryConstExpression(const AidlLocation & location,std::unique_ptr<AidlConstantValue> lval,const string & op,std::unique_ptr<AidlConstantValue> rval)1169 AidlBinaryConstExpression::AidlBinaryConstExpression(const AidlLocation& location,
1170                                                      std::unique_ptr<AidlConstantValue> lval,
1171                                                      const string& op,
1172                                                      std::unique_ptr<AidlConstantValue> rval)
1173     : AidlConstantValue(location, Type::BINARY, lval->value_ + op + rval->value_),
1174       left_val_(std::move(lval)),
1175       right_val_(std::move(rval)),
1176       op_(op) {
1177   final_type_ = Type::BINARY;
1178 }
1179