================
@@ -61,6 +59,48 @@ __attribute__((const, pure)) int func7(void); //
expected-warning {{'const' attr
// FIXME: this should also be diagnosed the same as func7.
__attribute__((pure)) int func8(void);
[[gnu::const]] int func8(void) {
- return 12;
+return 12;
}
+// Diagnosing invalid 'pure'/'const' attributes: writes through a pointer or
+// reference parameter, or to a global/static variable, violate the
+// attribute's no-visible-side-effects contract.
+
+int lookup(int key, int *value) __attribute__((__pure__));
+int lookup(int key, int *value) { // expected-note {{function declared 'pure'
here}}
+ if (key == 42) {
+ *value = 47; // expected-warning {{function declared 'pure' stores through
pointer parameter 'value'}}
+ return 0;
+ }
+ return -1;
+}
+
+static int global_cache;
+__attribute__((pure)) int writes_global(int x) { // expected-note {{function
declared 'pure' here}}
+ global_cache = x; // expected-warning {{function declared 'pure' stores to
global variable 'global_cache'}}
+ return global_cache;
+}
+
+__attribute__((pure)) int writes_static_local(int x) { // expected-note
{{function declared 'pure' here}}
+ static int cache = 0;
+ cache += x; // expected-warning {{function declared 'pure' stores to static
local variable 'cache'}}
+ return cache;
+}
+
+// No warning: local, non-static variable.
+__attribute__((pure)) int local_only(int x) {
+ int tmp = x * 2;
+ return tmp;
+}
+
+// No warning: read-only dereference of a const pointer.
+__attribute__((pure)) int reads_ptr_arg(const int *value) {
+ return *value;
+}
+
+#ifdef __cplusplus
+__attribute__((pure)) int writes_ref_arg(int &out) { // expected-note
{{function declared 'pure' here}}
+ out = 1; // expected-warning {{function declared 'pure' stores through
reference parameter 'out'}}
+ return 0;
+}
+#endif
----------------
ojhunt wrote:
new line according to GH review
https://github.com/llvm/llvm-project/pull/217817
_______________________________________________
cfe-commits mailing list
[email protected]
https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
