File: mul_by_const.cc

package info (click to toggle)
llvm-toolchain-6.0 1%3A6.0.1-10
  • links: PTS, VCS
  • area: main
  • in suites: buster
  • size: 598,080 kB
  • sloc: cpp: 3,046,253; ansic: 595,057; asm: 271,965; python: 128,926; objc: 106,554; sh: 21,906; lisp: 10,191; pascal: 6,094; ml: 5,544; perl: 5,265; makefile: 2,227; cs: 2,027; xml: 686; php: 212; csh: 117
file content (27 lines) | stat: -rw-r--r-- 631 bytes parent folder | download | duplicates (50)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
// RUN: %clangxx_msan -O2 %s -o %t && %run %t

#include <sanitizer/msan_interface.h>

struct S {
  S(int a0) : a(a0) {}
  int a;
  int b;
};

// Here S is passed to FooRun as a 64-bit integer.
// This triggers an optimization where 10000 * s.a is transformed into
// ((*(uint64_t *)&s) * (10000 * 2**32)) >> 32
// Test that MSan understands that this kills the uninitialized high half of S
// (i.e. S::b).
void FooRun(S s) {
  int64_t x = 10000 * s.a;
  __msan_check_mem_is_initialized(&x, sizeof(x));
}

int main(void) {
  S z(1);
  // Take &z to ensure that it is built on stack.
  S *volatile p = &z;
  FooRun(z);
  return 0;
}