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Optional SIMD strlen #586
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Optional SIMD strlen #586
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Optional SIMD strlen
ncruces 28d54cd
Consistent formatting.
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Comment.
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Pass CI.
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Add test.
ncruces 85bf59b
Avoid constant.
ncruces 13d318b
Test crosses page boundary.
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Comments.
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Typo.
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Avoid undefined behavior.
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CI test.
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Fix.
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Workflow name, comments.
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Original file line number | Diff line number | Diff line change |
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//! add-flags.py(LDFLAGS): -Wl,--stack-first -Wl,--initial-memory=327680 | ||
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#include <__macro_PAGESIZE.h> | ||
#include <stdio.h> | ||
#include <string.h> | ||
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void test(char *ptr, size_t want) { | ||
size_t got = strlen(ptr); | ||
if (got != want) { | ||
printf("strlen(%p) = %lu, want %lu\n", ptr, got, want); | ||
} | ||
} | ||
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int main(void) { | ||
char *const LIMIT = (char *)(__builtin_wasm_memory_size(0) * PAGESIZE); | ||
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for (size_t length = 0; length < 64; length++) { | ||
for (size_t alignment = 0; alignment < 24; alignment++) { | ||
// Create a string with the given length, at a pointer with the given | ||
// alignment. Using the offset LIMIT - PAGESIZE - 8 means many strings | ||
// will straddle a (Wasm, and likely OS) page boundary. | ||
char *ptr = LIMIT - PAGESIZE - 8 + alignment; | ||
memset(LIMIT - 2 * PAGESIZE, 0, 2 * PAGESIZE); | ||
memset(ptr, 5, length); | ||
test(ptr, length); | ||
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// Make sure we're not fooled by non-zero characters prior to the string. | ||
ptr[-1] = 5; | ||
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test(ptr, length); | ||
} | ||
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// Ensure we never read past the end of memory. | ||
char *ptr = LIMIT - length - 1; | ||
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memset(LIMIT - 2 * PAGESIZE, 0, 2 * PAGESIZE); | ||
memset(ptr, 5, length); | ||
test(ptr, length); | ||
} | ||
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return 0; | ||
} |
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