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comparison clang/test/SemaCXX/constexpr-string.cpp @ 150:1d019706d866

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LLVM10
author anatofuz
date Thu, 13 Feb 2020 15:10:13 +0900
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children 0572611fdcc8
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147:c2174574ed3a 150:1d019706d866
1 // RUN: %clang_cc1 %s -triple x86_64-linux-gnu -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension
2 // RUN: %clang_cc1 %s -triple x86_64-linux-gnu -std=gnu++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -DGNUMODE
3 // RUN: %clang_cc1 %s -triple x86_64-linux-gnu -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -fno-signed-char
4 // RUN: %clang_cc1 %s -triple x86_64-linux-gnu -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -fno-wchar -DNO_PREDEFINED_WCHAR_T
5 // RUN: %clang_cc1 %s -triple armebv7-unknown-linux -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension
6 // RUN: %clang_cc1 %s -triple armebv7-unknown-linux -std=gnu++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -DGNUMODE
7 // RUN: %clang_cc1 %s -triple armebv7-unknown-linux -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -fno-signed-char
8 // RUN: %clang_cc1 %s -triple armebv7-unknown-linux -std=c++2a -fsyntax-only -verify -pedantic -Wno-vla-extension -fno-wchar -DNO_PREDEFINED_WCHAR_T
9
10 # 9 "/usr/include/string.h" 1 3 4
11 extern "C" {
12 typedef decltype(sizeof(int)) size_t;
13
14 extern size_t strlen(const char *p);
15
16 extern int strcmp(const char *s1, const char *s2);
17 extern int strncmp(const char *s1, const char *s2, size_t n);
18 extern int memcmp(const void *s1, const void *s2, size_t n);
19
20 #ifdef GNUMODE
21 extern int bcmp(const void *s1, const void *s2, size_t n);
22 #endif
23
24 extern char *strchr(const char *s, int c);
25 extern void *memchr(const void *s, int c, size_t n);
26
27 extern void *memcpy(void *d, const void *s, size_t n);
28 extern void *memmove(void *d, const void *s, size_t n);
29 }
30 # 25 "SemaCXX/constexpr-string.cpp" 2
31
32 # 27 "/usr/include/wchar.h" 1 3 4
33 extern "C" {
34 #if NO_PREDEFINED_WCHAR_T
35 typedef decltype(L'0') wchar_t;
36 #endif
37 extern size_t wcslen(const wchar_t *p);
38
39 extern int wcscmp(const wchar_t *s1, const wchar_t *s2);
40 extern int wcsncmp(const wchar_t *s1, const wchar_t *s2, size_t n);
41 extern int wmemcmp(const wchar_t *s1, const wchar_t *s2, size_t n);
42
43 extern wchar_t *wcschr(const wchar_t *s, wchar_t c);
44 extern wchar_t *wmemchr(const wchar_t *s, wchar_t c, size_t n);
45
46 extern wchar_t *wmemcpy(wchar_t *d, const wchar_t *s, size_t n);
47 extern wchar_t *wmemmove(wchar_t *d, const wchar_t *s, size_t n);
48 }
49
50 # 45 "SemaCXX/constexpr-string.cpp" 2
51 namespace Strlen {
52 constexpr int n = __builtin_strlen("hello"); // ok
53 static_assert(n == 5);
54 constexpr int wn = __builtin_wcslen(L"hello"); // ok
55 static_assert(wn == 5);
56 constexpr int m = strlen("hello"); // expected-error {{constant expression}} expected-note {{non-constexpr function 'strlen' cannot be used in a constant expression}}
57 constexpr int wm = wcslen(L"hello"); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wcslen' cannot be used in a constant expression}}
58
59 // Make sure we can evaluate a call to strlen.
60 int arr[3]; // expected-note 2{{here}}
61 int k = arr[strlen("hello")]; // expected-warning {{array index 5}}
62 int wk = arr[wcslen(L"hello")]; // expected-warning {{array index 5}}
63 }
64
65 namespace StrcmpEtc {
66 constexpr char kFoobar[6] = {'f','o','o','b','a','r'};
67 constexpr char kFoobazfoobar[12] = {'f','o','o','b','a','z','f','o','o','b','a','r'};
68
69 static_assert(__builtin_strcmp("abab", "abab") == 0);
70 static_assert(__builtin_strcmp("abab", "abba") == -1);
71 static_assert(__builtin_strcmp("abab", "abaa") == 1);
72 static_assert(__builtin_strcmp("ababa", "abab") == 1);
73 static_assert(__builtin_strcmp("abab", "ababa") == -1);
74 static_assert(__builtin_strcmp("a\203", "a") == 1);
75 static_assert(__builtin_strcmp("a\203", "a\003") == 1);
76 static_assert(__builtin_strcmp("abab\0banana", "abab") == 0);
77 static_assert(__builtin_strcmp("abab", "abab\0banana") == 0);
78 static_assert(__builtin_strcmp("abab\0banana", "abab\0canada") == 0);
79 static_assert(__builtin_strcmp(0, "abab") == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
80 static_assert(__builtin_strcmp("abab", 0) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
81
82 static_assert(__builtin_strcmp(kFoobar, kFoobazfoobar) == -1); // FIXME: Should we reject this?
83 static_assert(__builtin_strcmp(kFoobar, kFoobazfoobar + 6) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
84
85 static_assert(__builtin_strncmp("abaa", "abba", 5) == -1);
86 static_assert(__builtin_strncmp("abaa", "abba", 4) == -1);
87 static_assert(__builtin_strncmp("abaa", "abba", 3) == -1);
88 static_assert(__builtin_strncmp("abaa", "abba", 2) == 0);
89 static_assert(__builtin_strncmp("abaa", "abba", 1) == 0);
90 static_assert(__builtin_strncmp("abaa", "abba", 0) == 0);
91 static_assert(__builtin_strncmp(0, 0, 0) == 0);
92 static_assert(__builtin_strncmp("abab\0banana", "abab\0canada", 100) == 0);
93
94 static_assert(__builtin_strncmp(kFoobar, kFoobazfoobar, 6) == -1);
95 static_assert(__builtin_strncmp(kFoobar, kFoobazfoobar, 7) == -1); // FIXME: Should we reject this?
96 static_assert(__builtin_strncmp(kFoobar, kFoobazfoobar + 6, 6) == 0);
97 static_assert(__builtin_strncmp(kFoobar, kFoobazfoobar + 6, 7) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
98
99 static_assert(__builtin_memcmp("abaa", "abba", 3) == -1);
100 static_assert(__builtin_memcmp("abaa", "abba", 2) == 0);
101 static_assert(__builtin_memcmp("a\203", "a", 2) == 1);
102 static_assert(__builtin_memcmp("a\203", "a\003", 2) == 1);
103 static_assert(__builtin_memcmp(0, 0, 0) == 0);
104 static_assert(__builtin_memcmp("abab\0banana", "abab\0banana", 100) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
105 static_assert(__builtin_memcmp("abab\0banana", "abab\0canada", 100) == -1); // FIXME: Should we reject this?
106 static_assert(__builtin_memcmp("abab\0banana", "abab\0canada", 7) == -1);
107 static_assert(__builtin_memcmp("abab\0banana", "abab\0canada", 6) == -1);
108 static_assert(__builtin_memcmp("abab\0banana", "abab\0canada", 5) == 0);
109
110 static_assert(__builtin_bcmp("abaa", "abba", 3) != 0);
111 static_assert(__builtin_bcmp("abaa", "abba", 2) == 0);
112 static_assert(__builtin_bcmp("a\203", "a", 2) != 0);
113 static_assert(__builtin_bcmp("a\203", "a\003", 2) != 0);
114 static_assert(__builtin_bcmp(0, 0, 0) == 0);
115 static_assert(__builtin_bcmp("abab\0banana", "abab\0banana", 100) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
116 static_assert(__builtin_bcmp("abab\0banana", "abab\0canada", 100) != 0); // FIXME: Should we reject this?
117 static_assert(__builtin_bcmp("abab\0banana", "abab\0canada", 7) != 0);
118 static_assert(__builtin_bcmp("abab\0banana", "abab\0canada", 6) != 0);
119 static_assert(__builtin_bcmp("abab\0banana", "abab\0canada", 5) == 0);
120
121 extern struct Incomplete incomplete;
122 static_assert(__builtin_memcmp(&incomplete, "", 0u) == 0);
123 static_assert(__builtin_memcmp("", &incomplete, 0u) == 0);
124 static_assert(__builtin_memcmp(&incomplete, "", 1u) == 42); // expected-error {{not an integral constant}} expected-note {{read of incomplete type 'struct Incomplete'}}
125 static_assert(__builtin_memcmp("", &incomplete, 1u) == 42); // expected-error {{not an integral constant}} expected-note {{read of incomplete type 'struct Incomplete'}}
126
127 static_assert(__builtin_bcmp(&incomplete, "", 0u) == 0);
128 static_assert(__builtin_bcmp("", &incomplete, 0u) == 0);
129 static_assert(__builtin_bcmp(&incomplete, "", 1u) == 42); // expected-error {{not an integral constant}} expected-note {{read of incomplete type 'struct Incomplete'}}
130 static_assert(__builtin_bcmp("", &incomplete, 1u) == 42); // expected-error {{not an integral constant}} expected-note {{read of incomplete type 'struct Incomplete'}}
131
132 constexpr unsigned char ku00fe00[] = {0x00, 0xfe, 0x00};
133 constexpr unsigned char ku00feff[] = {0x00, 0xfe, 0xff};
134 constexpr signed char ks00fe00[] = {0, -2, 0};
135 constexpr signed char ks00feff[] = {0, -2, -1};
136 static_assert(__builtin_memcmp(ku00feff, ks00fe00, 2) == 0);
137 static_assert(__builtin_memcmp(ku00feff, ks00fe00, 99) == 1);
138 static_assert(__builtin_memcmp(ku00fe00, ks00feff, 99) == -1);
139 static_assert(__builtin_memcmp(ks00feff, ku00fe00, 2) == 0);
140 static_assert(__builtin_memcmp(ks00feff, ku00fe00, 99) == 1);
141 static_assert(__builtin_memcmp(ks00fe00, ku00feff, 99) == -1);
142 static_assert(__builtin_memcmp(ks00fe00, ks00feff, 2) == 0);
143 static_assert(__builtin_memcmp(ks00feff, ks00fe00, 99) == 1);
144 static_assert(__builtin_memcmp(ks00fe00, ks00feff, 99) == -1);
145
146 static_assert(__builtin_bcmp(ku00feff, ks00fe00, 2) == 0);
147 static_assert(__builtin_bcmp(ku00feff, ks00fe00, 99) != 0);
148 static_assert(__builtin_bcmp(ku00fe00, ks00feff, 99) != 0);
149 static_assert(__builtin_bcmp(ks00feff, ku00fe00, 2) == 0);
150 static_assert(__builtin_bcmp(ks00feff, ku00fe00, 99) != 0);
151 static_assert(__builtin_bcmp(ks00fe00, ku00feff, 99) != 0);
152 static_assert(__builtin_bcmp(ks00fe00, ks00feff, 2) == 0);
153 static_assert(__builtin_bcmp(ks00feff, ks00fe00, 99) != 0);
154 static_assert(__builtin_bcmp(ks00fe00, ks00feff, 99) != 0);
155
156 struct Bool3Tuple { bool bb[3]; };
157 constexpr Bool3Tuple kb000100 = {{false, true, false}};
158 static_assert(sizeof(bool) != 1u || __builtin_memcmp(ks00fe00, kb000100.bb, 1) == 0);
159 static_assert(sizeof(bool) != 1u || __builtin_memcmp(ks00fe00, kb000100.bb, 2) == 1);
160
161 static_assert(sizeof(bool) != 1u || __builtin_bcmp(ks00fe00, kb000100.bb, 1) == 0);
162 static_assert(sizeof(bool) != 1u || __builtin_bcmp(ks00fe00, kb000100.bb, 2) != 0);
163
164 constexpr long ksl[] = {0, -1};
165 constexpr unsigned int kui[] = {0, 0u - 1};
166 constexpr unsigned long long kull[] = {0, 0ull - 1};
167 constexpr const auto *kuSizeofLong(void) {
168 if constexpr(sizeof(long) == sizeof(int)) {
169 return kui;
170 } else if constexpr(sizeof(long) == sizeof(long long)) {
171 return kull;
172 } else {
173 return nullptr;
174 }
175 }
176 static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) - 1) == 0);
177 static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) + 0) == 0);
178 static_assert(__builtin_memcmp(ksl, kuSizeofLong(), sizeof(long) + 1) == 0);
179 static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) - 1) == 0);
180 static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) + 0) == 0);
181 static_assert(__builtin_memcmp(ksl, kuSizeofLong(), 2*sizeof(long) + 1) == 42); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
182 static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) - 1) == 0);
183 static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) + 0) == 0);
184 static_assert(__builtin_memcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) + 1) == 42); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
185
186 static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) - 1) == 0);
187 static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) + 0) == 0);
188 static_assert(__builtin_bcmp(ksl, kuSizeofLong(), sizeof(long) + 1) == 0);
189 static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) - 1) == 0);
190 static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) + 0) == 0);
191 static_assert(__builtin_bcmp(ksl, kuSizeofLong(), 2*sizeof(long) + 1) == 42); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
192 static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) - 1) == 0);
193 static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) + 0) == 0);
194 static_assert(__builtin_bcmp(ksl + 1, kuSizeofLong() + 1, sizeof(long) + 1) == 42); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
195
196 constexpr int a = strcmp("hello", "world"); // expected-error {{constant expression}} expected-note {{non-constexpr function 'strcmp' cannot be used in a constant expression}}
197 constexpr int b = strncmp("hello", "world", 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'strncmp' cannot be used in a constant expression}}
198 constexpr int c = memcmp("hello", "world", 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'memcmp' cannot be used in a constant expression}}
199
200 #ifdef GNUMODE
201 constexpr int d = bcmp("hello", "world", 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'bcmp' cannot be used in a constant expression}}
202 #endif
203 }
204
205 namespace MultibyteElementTests {
206 inline namespace Util {
207 #define STR2(X) #X
208 #define STR(X) STR2(X)
209 constexpr const char ByteOrderString[] = STR(__BYTE_ORDER__);
210 #undef STR
211 #undef STR2
212 constexpr bool LittleEndian{*ByteOrderString == '1'};
213
214 constexpr size_t GoodFoldArraySize = 42, BadFoldArraySize = 43;
215 struct NotBadFoldResult {};
216 template <size_t> struct FoldResult;
217 template <> struct FoldResult<GoodFoldArraySize> : NotBadFoldResult {};
218 template <typename T, size_t N>
219 FoldResult<N> *foldResultImpl(T (*ptrToConstantSizeArray)[N]);
220 struct NotFolded : NotBadFoldResult {};
221 NotFolded *foldResultImpl(bool anyPtr);
222 template <auto Value> struct MetaValue;
223 template <typename Callable, size_t N, auto ExpectedFoldResult>
224 auto foldResult(const Callable &, MetaValue<N> *,
225 MetaValue<ExpectedFoldResult> *) {
226 int (*maybeVLAPtr)[Callable{}(N) == ExpectedFoldResult
227 ? GoodFoldArraySize
228 : BadFoldArraySize] = 0;
229 return foldResultImpl(maybeVLAPtr);
230 }
231 template <typename FoldResultKind, typename Callable, typename NWrap,
232 typename ExpectedWrap>
233 constexpr bool checkFoldResult(const Callable &c, NWrap *n, ExpectedWrap *e) {
234 decltype(static_cast<FoldResultKind *>(foldResult(c, n, e))) *chk{};
235 return true;
236 }
237 template <size_t N> constexpr MetaValue<N> *withN() { return nullptr; }
238 template <auto Expected> constexpr MetaValue<Expected> *withExpected() {
239 return nullptr;
240 }
241 } // namespace Util
242 } // namespace MultibyteElementTests
243
244 namespace MultibyteElementTests::Memcmp {
245 #ifdef __SIZEOF_INT128__
246 constexpr __int128 i128_ff_8_00_8 = -(__int128)1 - -1ull;
247 constexpr __int128 i128_00_16 = 0;
248 static_assert(checkFoldResult<NotBadFoldResult>(
249 [](size_t n) constexpr {
250 return __builtin_memcmp(&i128_ff_8_00_8, &i128_00_16, n);
251 },
252 withN<1u>(), withExpected<LittleEndian ? 0 : 1>()));
253 #endif
254
255 constexpr const signed char ByteOrderStringReduced[] = {
256 ByteOrderString[0] - '0', ByteOrderString[1] - '0',
257 ByteOrderString[2] - '0', ByteOrderString[3] - '0',
258 };
259 constexpr signed int i04030201 = 0x04030201;
260 constexpr unsigned int u04030201 = 0x04030201u;
261 static_assert(checkFoldResult<NotBadFoldResult>(
262 [](size_t n) constexpr {
263 return __builtin_memcmp(ByteOrderStringReduced, &i04030201, n);
264 },
265 withN<sizeof(int)>(), withExpected<0>()));
266 static_assert(checkFoldResult<NotBadFoldResult>(
267 [](size_t n) constexpr {
268 return __builtin_memcmp(&u04030201, ByteOrderStringReduced, n);
269 },
270 withN<sizeof(int)>(), withExpected<0>()));
271
272 constexpr unsigned int ui0000FEFF = 0x0000feffU;
273 constexpr unsigned short usFEFF = 0xfeffU;
274 static_assert(checkFoldResult<NotBadFoldResult>(
275 [](size_t n) constexpr {
276 return __builtin_memcmp(&ui0000FEFF, &usFEFF, n);
277 },
278 withN<1u>(), withExpected<LittleEndian ? 0 : -1>()));
279
280 constexpr unsigned int ui08038700 = 0x08038700u;
281 constexpr unsigned int ui08048600 = 0x08048600u;
282 static_assert(checkFoldResult<NotBadFoldResult>(
283 [](size_t n) constexpr {
284 return __builtin_memcmp(&ui08038700, &ui08048600, n);
285 },
286 withN<sizeof(int)>(), withExpected<LittleEndian ? 1 : -1>()));
287 }
288
289 namespace WcscmpEtc {
290 constexpr wchar_t kFoobar[6] = {L'f',L'o',L'o',L'b',L'a',L'r'};
291 constexpr wchar_t kFoobazfoobar[12] = {L'f',L'o',L'o',L'b',L'a',L'z',L'f',L'o',L'o',L'b',L'a',L'r'};
292
293 static_assert(__builtin_wcscmp(L"abab", L"abab") == 0);
294 static_assert(__builtin_wcscmp(L"abab", L"abba") == -1);
295 static_assert(__builtin_wcscmp(L"abab", L"abaa") == 1);
296 static_assert(__builtin_wcscmp(L"ababa", L"abab") == 1);
297 static_assert(__builtin_wcscmp(L"abab", L"ababa") == -1);
298 static_assert(__builtin_wcscmp(L"abab\0banana", L"abab") == 0);
299 static_assert(__builtin_wcscmp(L"abab", L"abab\0banana") == 0);
300 static_assert(__builtin_wcscmp(L"abab\0banana", L"abab\0canada") == 0);
301 #if __WCHAR_WIDTH__ == 32
302 static_assert(__builtin_wcscmp(L"a\x83838383", L"a") == (wchar_t)-1U >> 31);
303 #endif
304 static_assert(__builtin_wcscmp(0, L"abab") == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
305 static_assert(__builtin_wcscmp(L"abab", 0) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
306
307 static_assert(__builtin_wcscmp(kFoobar, kFoobazfoobar) == -1); // FIXME: Should we reject this?
308 static_assert(__builtin_wcscmp(kFoobar, kFoobazfoobar + 6) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
309
310 static_assert(__builtin_wcsncmp(L"abaa", L"abba", 5) == -1);
311 static_assert(__builtin_wcsncmp(L"abaa", L"abba", 4) == -1);
312 static_assert(__builtin_wcsncmp(L"abaa", L"abba", 3) == -1);
313 static_assert(__builtin_wcsncmp(L"abaa", L"abba", 2) == 0);
314 static_assert(__builtin_wcsncmp(L"abaa", L"abba", 1) == 0);
315 static_assert(__builtin_wcsncmp(L"abaa", L"abba", 0) == 0);
316 static_assert(__builtin_wcsncmp(0, 0, 0) == 0);
317 static_assert(__builtin_wcsncmp(L"abab\0banana", L"abab\0canada", 100) == 0);
318 #if __WCHAR_WIDTH__ == 32
319 static_assert(__builtin_wcsncmp(L"a\x83838383", L"aa", 2) ==
320 (wchar_t)-1U >> 31);
321 #endif
322
323 static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar, 6) == -1);
324 static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar, 7) == -1); // FIXME: Should we reject this?
325 static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar + 6, 6) == 0);
326 static_assert(__builtin_wcsncmp(kFoobar, kFoobazfoobar + 6, 7) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
327
328 static_assert(__builtin_wmemcmp(L"abaa", L"abba", 3) == -1);
329 static_assert(__builtin_wmemcmp(L"abaa", L"abba", 2) == 0);
330 static_assert(__builtin_wmemcmp(0, 0, 0) == 0);
331 #if __WCHAR_WIDTH__ == 32
332 static_assert(__builtin_wmemcmp(L"a\x83838383", L"aa", 2) ==
333 (wchar_t)-1U >> 31);
334 #endif
335 static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0banana", 100) == 0); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
336 static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 100) == -1); // FIXME: Should we reject this?
337 static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 7) == -1);
338 static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 6) == -1);
339 static_assert(__builtin_wmemcmp(L"abab\0banana", L"abab\0canada", 5) == 0);
340
341 constexpr int a = wcscmp(L"hello", L"world"); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wcscmp' cannot be used in a constant expression}}
342 constexpr int b = wcsncmp(L"hello", L"world", 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wcsncmp' cannot be used in a constant expression}}
343 constexpr int c = wmemcmp(L"hello", L"world", 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wmemcmp' cannot be used in a constant expression}}
344 }
345
346 namespace StrchrEtc {
347 constexpr const char *kStr = "abca\xff\0d";
348 constexpr char kFoo[] = {'f', 'o', 'o'};
349 static_assert(__builtin_strchr(kStr, 'a') == kStr);
350 static_assert(__builtin_strchr(kStr, 'b') == kStr + 1);
351 static_assert(__builtin_strchr(kStr, 'c') == kStr + 2);
352 static_assert(__builtin_strchr(kStr, 'd') == nullptr);
353 static_assert(__builtin_strchr(kStr, 'e') == nullptr);
354 static_assert(__builtin_strchr(kStr, '\0') == kStr + 5);
355 static_assert(__builtin_strchr(kStr, 'a' + 256) == nullptr);
356 static_assert(__builtin_strchr(kStr, 'a' - 256) == nullptr);
357 static_assert(__builtin_strchr(kStr, '\xff') == kStr + 4);
358 static_assert(__builtin_strchr(kStr, '\xff' + 256) == nullptr);
359 static_assert(__builtin_strchr(kStr, '\xff' - 256) == nullptr);
360 static_assert(__builtin_strchr(kFoo, 'o') == kFoo + 1);
361 static_assert(__builtin_strchr(kFoo, 'x') == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
362 static_assert(__builtin_strchr(nullptr, 'x') == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
363
364 static_assert(__builtin_memchr(kStr, 'a', 0) == nullptr);
365 static_assert(__builtin_memchr(kStr, 'a', 1) == kStr);
366 static_assert(__builtin_memchr(kStr, '\0', 5) == nullptr);
367 static_assert(__builtin_memchr(kStr, '\0', 6) == kStr + 5);
368 static_assert(__builtin_memchr(kStr, '\xff', 8) == kStr + 4);
369 static_assert(__builtin_memchr(kStr, '\xff' + 256, 8) == kStr + 4);
370 static_assert(__builtin_memchr(kStr, '\xff' - 256, 8) == kStr + 4);
371 static_assert(__builtin_memchr(kFoo, 'x', 3) == nullptr);
372 static_assert(__builtin_memchr(kFoo, 'x', 4) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
373 static_assert(__builtin_memchr(nullptr, 'x', 3) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
374 static_assert(__builtin_memchr(nullptr, 'x', 0) == nullptr); // FIXME: Should we reject this?
375
376 extern struct Incomplete incomplete;
377 static_assert(__builtin_memchr(&incomplete, 0, 0u) == nullptr);
378 static_assert(__builtin_memchr(&incomplete, 0, 1u) == nullptr); // expected-error {{not an integral constant}} expected-note {{read of incomplete type 'struct Incomplete'}}
379
380 const unsigned char &u1 = 0xf0;
381 auto &&i1 = (const signed char []){-128}; // expected-warning {{compound literals are a C99-specific feature}}
382 static_assert(__builtin_memchr(&u1, -(0x0f + 1), 1) == &u1);
383 static_assert(__builtin_memchr(i1, 0x80, 1) == i1);
384
385 enum class E : unsigned char {};
386 struct EPair { E e, f; };
387 constexpr EPair ee{E{240}};
388 static_assert(__builtin_memchr(&ee.e, 240, 1) == &ee.e);
389
390 constexpr bool kBool[] = {false, true, false};
391 constexpr const bool *const kBoolPastTheEndPtr = kBool + 3;
392 static_assert(sizeof(bool) != 1u || __builtin_memchr(kBoolPastTheEndPtr - 3, 1, 99) == kBool + 1);
393 static_assert(sizeof(bool) != 1u || __builtin_memchr(kBool + 1, 0, 99) == kBoolPastTheEndPtr - 1);
394 static_assert(sizeof(bool) != 1u || __builtin_memchr(kBoolPastTheEndPtr - 3, -1, 3) == nullptr);
395 static_assert(sizeof(bool) != 1u || __builtin_memchr(kBoolPastTheEndPtr, 0, 1) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
396
397 static_assert(__builtin_char_memchr(kStr, 'a', 0) == nullptr);
398 static_assert(__builtin_char_memchr(kStr, 'a', 1) == kStr);
399 static_assert(__builtin_char_memchr(kStr, '\0', 5) == nullptr);
400 static_assert(__builtin_char_memchr(kStr, '\0', 6) == kStr + 5);
401 static_assert(__builtin_char_memchr(kStr, '\xff', 8) == kStr + 4);
402 static_assert(__builtin_char_memchr(kStr, '\xff' + 256, 8) == kStr + 4);
403 static_assert(__builtin_char_memchr(kStr, '\xff' - 256, 8) == kStr + 4);
404 static_assert(__builtin_char_memchr(kFoo, 'x', 3) == nullptr);
405 static_assert(__builtin_char_memchr(kFoo, 'x', 4) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
406 static_assert(__builtin_char_memchr(nullptr, 'x', 3) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
407 static_assert(__builtin_char_memchr(nullptr, 'x', 0) == nullptr); // FIXME: Should we reject this?
408
409 static_assert(*__builtin_char_memchr(kStr, '\xff', 8) == '\xff');
410 constexpr bool char_memchr_mutable() {
411 char buffer[] = "mutable";
412 *__builtin_char_memchr(buffer, 't', 8) = 'r';
413 *__builtin_char_memchr(buffer, 'm', 8) = 'd';
414 return __builtin_strcmp(buffer, "durable") == 0;
415 }
416 static_assert(char_memchr_mutable());
417
418 constexpr bool a = !strchr("hello", 'h'); // expected-error {{constant expression}} expected-note {{non-constexpr function 'strchr' cannot be used in a constant expression}}
419 constexpr bool b = !memchr("hello", 'h', 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'memchr' cannot be used in a constant expression}}
420 }
421
422 namespace MultibyteElementTests::Memchr {
423 constexpr unsigned int u04030201 = 0x04030201;
424 static_assert(checkFoldResult<NotBadFoldResult>(
425 [](size_t n) constexpr {
426 return __builtin_memchr(&u04030201, *ByteOrderString - '0', n);
427 },
428 withN<1u>(), withExpected<&u04030201>()));
429
430 constexpr unsigned int uED = 0xEDU;
431 static_assert(checkFoldResult<NotBadFoldResult>(
432 [](size_t n) constexpr {
433 return __builtin_memchr(&uED, 0xED, n);
434 },
435 withN<1u>(), withExpected<LittleEndian ? &uED : nullptr>()));
436 }
437
438 namespace WcschrEtc {
439 constexpr const wchar_t *kStr = L"abca\xffff\0dL";
440 constexpr wchar_t kFoo[] = {L'f', L'o', L'o'};
441 static_assert(__builtin_wcschr(kStr, L'a') == kStr);
442 static_assert(__builtin_wcschr(kStr, L'b') == kStr + 1);
443 static_assert(__builtin_wcschr(kStr, L'c') == kStr + 2);
444 static_assert(__builtin_wcschr(kStr, L'd') == nullptr);
445 static_assert(__builtin_wcschr(kStr, L'e') == nullptr);
446 static_assert(__builtin_wcschr(kStr, L'\0') == kStr + 5);
447 static_assert(__builtin_wcschr(kStr, L'a' + 256) == nullptr);
448 static_assert(__builtin_wcschr(kStr, L'a' - 256) == nullptr);
449 static_assert(__builtin_wcschr(kStr, L'\xffff') == kStr + 4);
450 static_assert(__builtin_wcschr(kFoo, L'o') == kFoo + 1);
451 static_assert(__builtin_wcschr(kFoo, L'x') == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
452 static_assert(__builtin_wcschr(nullptr, L'x') == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
453
454 static_assert(__builtin_wmemchr(kStr, L'a', 0) == nullptr);
455 static_assert(__builtin_wmemchr(kStr, L'a', 1) == kStr);
456 static_assert(__builtin_wmemchr(kStr, L'\0', 5) == nullptr);
457 static_assert(__builtin_wmemchr(kStr, L'\0', 6) == kStr + 5);
458 static_assert(__builtin_wmemchr(kStr, L'\xffff', 8) == kStr + 4);
459 static_assert(__builtin_wmemchr(kFoo, L'x', 3) == nullptr);
460 static_assert(__builtin_wmemchr(kFoo, L'x', 4) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced one-past-the-end}}
461 static_assert(__builtin_wmemchr(nullptr, L'x', 3) == nullptr); // expected-error {{not an integral constant}} expected-note {{dereferenced null}}
462 static_assert(__builtin_wmemchr(nullptr, L'x', 0) == nullptr); // FIXME: Should we reject this?
463
464 constexpr bool a = !wcschr(L"hello", L'h'); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wcschr' cannot be used in a constant expression}}
465 constexpr bool b = !wmemchr(L"hello", L'h', 3); // expected-error {{constant expression}} expected-note {{non-constexpr function 'wmemchr' cannot be used in a constant expression}}
466 }
467
468 namespace MemcpyEtc {
469 template<typename T>
470 constexpr T result(T (&arr)[4]) {
471 return arr[0] * 1000 + arr[1] * 100 + arr[2] * 10 + arr[3];
472 }
473
474 constexpr int test_memcpy(int a, int b, int n) {
475 int arr[4] = {1, 2, 3, 4};
476 __builtin_memcpy(arr + a, arr + b, n);
477 // expected-note@-1 2{{overlapping memory regions}}
478 // expected-note@-2 {{size to copy (1) is not a multiple of size of element type 'int'}}
479 // expected-note@-3 {{source is not a contiguous array of at least 2 elements of type 'int'}}
480 // expected-note@-4 {{destination is not a contiguous array of at least 3 elements of type 'int'}}
481 return result(arr);
482 }
483 constexpr int test_memmove(int a, int b, int n) {
484 int arr[4] = {1, 2, 3, 4};
485 __builtin_memmove(arr + a, arr + b, n);
486 // expected-note@-1 {{size to copy (1) is not a multiple of size of element type 'int'}}
487 // expected-note@-2 {{source is not a contiguous array of at least 2 elements of type 'int'}}
488 // expected-note@-3 {{destination is not a contiguous array of at least 3 elements of type 'int'}}
489 return result(arr);
490 }
491 constexpr int test_wmemcpy(int a, int b, int n) {
492 wchar_t arr[4] = {1, 2, 3, 4};
493 __builtin_wmemcpy(arr + a, arr + b, n);
494 // expected-note@-1 2{{overlapping memory regions}}
495 // expected-note@-2 {{source is not a contiguous array of at least 2 elements of type 'wchar_t'}}
496 // expected-note@-3 {{destination is not a contiguous array of at least 3 elements of type 'wchar_t'}}
497 return result(arr);
498 }
499 constexpr int test_wmemmove(int a, int b, int n) {
500 wchar_t arr[4] = {1, 2, 3, 4};
501 __builtin_wmemmove(arr + a, arr + b, n);
502 // expected-note@-1 {{source is not a contiguous array of at least 2 elements of type 'wchar_t'}}
503 // expected-note@-2 {{destination is not a contiguous array of at least 3 elements of type 'wchar_t'}}
504 return result(arr);
505 }
506
507 static_assert(test_memcpy(1, 2, 4) == 1334);
508 static_assert(test_memcpy(2, 1, 4) == 1224);
509 static_assert(test_memcpy(0, 1, 8) == 2334); // expected-error {{constant}} expected-note {{in call}}
510 static_assert(test_memcpy(1, 0, 8) == 1124); // expected-error {{constant}} expected-note {{in call}}
511 static_assert(test_memcpy(1, 2, 1) == 1334); // expected-error {{constant}} expected-note {{in call}}
512 static_assert(test_memcpy(0, 3, 4) == 4234);
513 static_assert(test_memcpy(0, 3, 8) == 4234); // expected-error {{constant}} expected-note {{in call}}
514 static_assert(test_memcpy(2, 0, 12) == 4234); // expected-error {{constant}} expected-note {{in call}}
515
516 static_assert(test_memmove(1, 2, 4) == 1334);
517 static_assert(test_memmove(2, 1, 4) == 1224);
518 static_assert(test_memmove(0, 1, 8) == 2334);
519 static_assert(test_memmove(1, 0, 8) == 1124);
520 static_assert(test_memmove(1, 2, 1) == 1334); // expected-error {{constant}} expected-note {{in call}}
521 static_assert(test_memmove(0, 3, 4) == 4234);
522 static_assert(test_memmove(0, 3, 8) == 4234); // expected-error {{constant}} expected-note {{in call}}
523 static_assert(test_memmove(2, 0, 12) == 4234); // expected-error {{constant}} expected-note {{in call}}
524
525 static_assert(test_wmemcpy(1, 2, 1) == 1334);
526 static_assert(test_wmemcpy(2, 1, 1) == 1224);
527 static_assert(test_wmemcpy(0, 1, 2) == 2334); // expected-error {{constant}} expected-note {{in call}}
528 static_assert(test_wmemcpy(1, 0, 2) == 1124); // expected-error {{constant}} expected-note {{in call}}
529 static_assert(test_wmemcpy(1, 2, 1) == 1334);
530 static_assert(test_wmemcpy(0, 3, 1) == 4234);
531 static_assert(test_wmemcpy(0, 3, 2) == 4234); // expected-error {{constant}} expected-note {{in call}}
532 static_assert(test_wmemcpy(2, 0, 3) == 4234); // expected-error {{constant}} expected-note {{in call}}
533
534 static_assert(test_wmemmove(1, 2, 1) == 1334);
535 static_assert(test_wmemmove(2, 1, 1) == 1224);
536 static_assert(test_wmemmove(0, 1, 2) == 2334);
537 static_assert(test_wmemmove(1, 0, 2) == 1124);
538 static_assert(test_wmemmove(1, 2, 1) == 1334);
539 static_assert(test_wmemmove(0, 3, 1) == 4234);
540 static_assert(test_wmemmove(0, 3, 2) == 4234); // expected-error {{constant}} expected-note {{in call}}
541 static_assert(test_wmemmove(2, 0, 3) == 4234); // expected-error {{constant}} expected-note {{in call}}
542
543 #define fold(x) (__builtin_constant_p(0) ? (x) : (x))
544
545 wchar_t global;
546 constexpr wchar_t *null = 0;
547 static_assert(__builtin_memcpy(&global, null, sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'memcpy' is nullptr}}
548 static_assert(__builtin_memmove(&global, null, sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'memmove' is nullptr}}
549 static_assert(__builtin_wmemcpy(&global, null, sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'wmemcpy' is nullptr}}
550 static_assert(__builtin_wmemmove(&global, null, sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'wmemmove' is nullptr}}
551 static_assert(__builtin_memcpy(null, &global, sizeof(wchar_t))); // expected-error {{}} expected-note {{destination of 'memcpy' is nullptr}}
552 static_assert(__builtin_memmove(null, &global, sizeof(wchar_t))); // expected-error {{}} expected-note {{destination of 'memmove' is nullptr}}
553 static_assert(__builtin_wmemcpy(null, &global, sizeof(wchar_t))); // expected-error {{}} expected-note {{destination of 'wmemcpy' is nullptr}}
554 static_assert(__builtin_wmemmove(null, &global, sizeof(wchar_t))); // expected-error {{}} expected-note {{destination of 'wmemmove' is nullptr}}
555 static_assert(__builtin_memcpy(&global, fold((wchar_t*)123), sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'memcpy' is (void *)123}}
556 static_assert(__builtin_memcpy(fold(reinterpret_cast<wchar_t*>(123)), &global, sizeof(wchar_t))); // expected-error {{}} expected-note {{destination of 'memcpy' is (void *)123}}
557 constexpr struct Incomplete *null_incomplete = 0;
558 static_assert(__builtin_memcpy(null_incomplete, null_incomplete, sizeof(wchar_t))); // expected-error {{}} expected-note {{source of 'memcpy' is nullptr}}
559
560 // Copying is permitted for any trivially-copyable type.
561 struct Trivial { char k; short s; constexpr bool ok() { return k == 3 && s == 4; } };
562 constexpr bool test_trivial() {
563 Trivial arr[3] = {{1, 2}, {3, 4}, {5, 6}};
564 __builtin_memcpy(arr, arr+1, sizeof(Trivial));
565 __builtin_memmove(arr+1, arr, 2 * sizeof(Trivial));
566 return arr[0].ok() && arr[1].ok() && arr[2].ok();
567 }
568 static_assert(test_trivial());
569
570 // But not for a non-trivially-copyable type.
571 struct NonTrivial {
572 constexpr NonTrivial() : n(0) {}
573 constexpr NonTrivial(const NonTrivial &) : n(1) {}
574 int n;
575 };
576 constexpr bool test_nontrivial_memcpy() { // expected-error {{never produces a constant}}
577 NonTrivial arr[3] = {};
578 __builtin_memcpy(arr, arr + 1, sizeof(NonTrivial)); // expected-note 2{{non-trivially-copyable}}
579 return true;
580 }
581 static_assert(test_nontrivial_memcpy()); // expected-error {{constant}} expected-note {{in call}}
582 constexpr bool test_nontrivial_memmove() { // expected-error {{never produces a constant}}
583 NonTrivial arr[3] = {};
584 __builtin_memcpy(arr, arr + 1, sizeof(NonTrivial)); // expected-note 2{{non-trivially-copyable}}
585 return true;
586 }
587 static_assert(test_nontrivial_memmove()); // expected-error {{constant}} expected-note {{in call}}
588
589 // Type puns via constant evaluated memcpy are not supported yet.
590 constexpr float type_pun(const unsigned &n) {
591 float f = 0.0f;
592 __builtin_memcpy(&f, &n, 4); // expected-note {{cannot constant evaluate 'memcpy' from object of type 'const unsigned int' to object of type 'float'}}
593 return f;
594 }
595 static_assert(type_pun(0x3f800000) == 1.0f); // expected-error {{constant}} expected-note {{in call}}
596
597 // Make sure we're not confused by derived-to-base conversions.
598 struct Base { int a; };
599 struct Derived : Base { int b; };
600 constexpr int test_derived_to_base(int n) {
601 Derived arr[2] = {1, 2, 3, 4};
602 Base *p = &arr[0];
603 Base *q = &arr[1];
604 __builtin_memcpy(p, q, sizeof(Base) * n); // expected-note {{source is not a contiguous array of at least 2 elements of type 'MemcpyEtc::Base'}}
605 return arr[0].a * 1000 + arr[0].b * 100 + arr[1].a * 10 + arr[1].b;
606 }
607 static_assert(test_derived_to_base(0) == 1234);
608 static_assert(test_derived_to_base(1) == 3234);
609 // FIXME: We could consider making this work by stripping elements off both
610 // designators until we have a long enough matching size, if both designators
611 // point to the start of their respective final elements.
612 static_assert(test_derived_to_base(2) == 3434); // expected-error {{constant}} expected-note {{in call}}
613
614 // Check that when address-of an array is passed to a tested function the
615 // array can be fully copied.
616 constexpr int test_address_of_const_array_type() {
617 int arr[4] = {1, 2, 3, 4};
618 __builtin_memmove(&arr, &arr, sizeof(arr));
619 return arr[0] * 1000 + arr[1] * 100 + arr[2] * 10 + arr[3];
620 }
621 static_assert(test_address_of_const_array_type() == 1234);
622
623 // Check that an incomplete array is rejected.
624 constexpr int test_incomplete_array_type() { // expected-error {{never produces a constant}}
625 extern int arr[];
626 __builtin_memmove(arr, arr, 4 * sizeof(arr[0]));
627 // expected-note@-1 2{{'memmove' not supported: source is not a contiguous array of at least 4 elements of type 'int'}}
628 return arr[0] * 1000 + arr[1] * 100 + arr[2] * 10 + arr[3];
629 }
630 static_assert(test_incomplete_array_type() == 1234); // expected-error {{constant}} expected-note {{in call}}
631
632 // Check that a pointer to an incomplete array is rejected.
633 constexpr int test_address_of_incomplete_array_type() { // expected-error {{never produces a constant}}
634 extern int arr[];
635 __builtin_memmove(&arr, &arr, 4 * sizeof(arr[0]));
636 // expected-note@-1 2{{cannot constant evaluate 'memmove' between objects of incomplete type 'int []'}}
637 return arr[0] * 1000 + arr[1] * 100 + arr[2] * 10 + arr[3];
638 }
639 static_assert(test_address_of_incomplete_array_type() == 1234); // expected-error {{constant}} expected-note {{in call}}
640
641 // Check that a pointer to an incomplete struct is rejected.
642 constexpr bool test_address_of_incomplete_struct_type() { // expected-error {{never produces a constant}}
643 struct Incomplete;
644 extern Incomplete x, y;
645 __builtin_memcpy(&x, &x, 4);
646 // expected-note@-1 2{{cannot constant evaluate 'memcpy' between objects of incomplete type 'Incomplete'}}
647 return true;
648 }
649 static_assert(test_address_of_incomplete_struct_type()); // expected-error {{constant}} expected-note {{in call}}
650 }