[clang] [compiler-rt] [libcxx] [clang] Add unistd fortify checks and analyzer size constraints (PR #196499)

[Oliver Hunt via cfe-commits]

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@@ -370,3 +370,61 @@ void test_file_fd_at_functions() {
   (void)readlinkat(AT_FDCWD, "newpath", Buf, 10);
   (void)renameat(AT_FDCWD, "oldpath", AT_FDCWD, "newpath");
 }
+
+#define SSIZE_MAX_PLUS_ONE ((size_t)1 << (sizeof(size_t) * __CHAR_BIT__ - 1))
+
+void test_read_ssize_max_io_size(int fd, char *Buf) {
+  read(fd, Buf, SSIZE_MAX_PLUS_ONE); // \
+  // report-warning{{The 3rd argument to 'read' is 9223372036854775808 but should be a value not greater than SSIZE_MAX}} \
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ojhunt wrote:

Just use `@-1`,`@-2`, etc

https://github.com/llvm/llvm-project/pull/196499