[compiler-rt] Fix possible underflow in ParseAndSetPath (PR #159389)

[Ellis Hoag via llvm-commits]

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@@ -106,6 +106,7 @@ static void ParseAndSetPath(const char *pattern, char *dest,
                             const uptr dest_size) {
   CHECK(pattern);
   CHECK(dest);
+  CHECK_NE(internal_strcmp(pattern, ""), 0);
   CHECK_GE(dest_size, 1);
   dest[0] = '\0';
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ellishg wrote:

Instead of crashing on the empty string, I think it's better to simply return here so that dest becomes "".

https://github.com/llvm/llvm-project/pull/159389