llvm-project

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// RUN: %clangxx_tsan -O1 %s -o %t && %run %t 2>&1 | FileCheck %s
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// UNSUPPORTED: ios
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#include "test.h"
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#include <sys/mman.h>
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// Test for previously unbounded memory consumption for large mallocs.
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// Code allocates a large memory block (that is handled by LargeMmapAllocator),
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// and forces allocation of meta shadow for the block. Then freed the block.
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// But meta shadow was not unmapped. Then code occupies the virtual memory
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// range of the block with something else (that does not need meta shadow).
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// And repeats. As the result meta shadow growed infinitely.
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// This program used to consume >2GB. Now it consumes <50MB.
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int main() {
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  for (int i = 0; i < 1000; i++) {
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    const int kSize = 1 << 20;
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    const int kPageSize = 4 << 10;
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    volatile int *p = new int[kSize];
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    for (int j = 0; j < kSize; j += kPageSize / sizeof(*p))
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      __atomic_store_n(&p[i], 1, __ATOMIC_RELEASE);
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    delete[] p;
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    mmap(0, kSize * sizeof(*p) + kPageSize, PROT_NONE, MAP_PRIVATE | MAP_ANON,
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        -1, 0);
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  }
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  fprintf(stderr, "DONE\n");
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  return 0;
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}
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// CHECK: DONE
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