C++: Exclude code in templates.

geoffw0 · geoffw0 · commit b2c5ce8dbdc1 · 2020-03-11T18:11:45.000Z
diff --git a/cpp/ql/src/Critical/NewDelete.qll b/cpp/ql/src/Critical/NewDelete.qll
@@ -12,6 +12,7 @@ import semmle.code.cpp.dataflow.DataFlow
  */
 predicate allocExpr(Expr alloc, string kind) {
   isAllocationExpr(alloc) and
+  not alloc.isFromUninstantiatedTemplate(_) and
   (
     alloc instanceof FunctionCall and
     kind = "malloc"
diff --git a/cpp/ql/test/query-tests/Critical/NewFree/NewFreeMismatch.expected b/cpp/ql/test/query-tests/Critical/NewFree/NewFreeMismatch.expected
@@ -1,7 +1,5 @@
-| test2.cpp:19:3:19:6 | call to free | There is a new/free mismatch between this free and the corresponding $@. | test2.cpp:18:10:18:14 | new | new |
-| test2.cpp:26:3:26:6 | call to free | There is a new/free mismatch between this free and the corresponding $@. | test2.cpp:25:7:25:11 | new | new |
-| test2.cpp:26:3:26:6 | call to free | There is a new/free mismatch between this free and the corresponding $@. | test2.cpp:25:7:25:11 | new | new |
-| test2.cpp:30:3:30:6 | call to free | There is a new/free mismatch between this free and the corresponding $@. | test2.cpp:29:7:29:18 | new | new |
+| test2.cpp:19:3:19:6 | call to free | There is a new/free mismatch between this free and the corresponding $@. | test2.cpp:18:12:18:18 | new | new |
+| test2.cpp:26:3:26:6 | call to free | There is a new/free mismatch between this free and the corresponding $@. | test2.cpp:25:7:25:13 | new | new |
 | test.cpp:36:2:36:17 | delete | There is a malloc/delete mismatch between this delete and the corresponding $@. | test.cpp:27:18:27:23 | call to malloc | malloc |
 | test.cpp:41:2:41:5 | call to free | There is a new/free mismatch between this free and the corresponding $@. | test.cpp:26:7:26:17 | new | new |
 | test.cpp:68:3:68:11 | delete | There is a malloc/delete mismatch between this delete and the corresponding $@. | test.cpp:64:28:64:33 | call to malloc | malloc |
diff --git a/cpp/ql/test/query-tests/Critical/NewFree/test2.cpp b/cpp/ql/test/query-tests/Critical/NewFree/test2.cpp
@@ -27,7 +27,7 @@ class MyTest2Class
 
 		int *ptr_d = (int *)malloc(sizeof(int));
 		d = new(ptr_d) int;
-		free(d); // GOOD [FALSE POSITIVE]
+		free(d); // GOOD
 	}
 
 	int *c, *d;

Original file line number	Diff line number	Diff line change
`@@ -12,6 +12,7 @@ import semmle.code.cpp.dataflow.DataFlow`
`12`	`12`	`*/`
`13`	`13`	`predicate allocExpr(Expr alloc, string kind) {`
`14`	`14`	`isAllocationExpr(alloc) and`
	`15`	`+ not alloc.isFromUninstantiatedTemplate(_) and`
`15`	`16`	`(`
`16`	`17`	`alloc instanceof FunctionCall and`
`17`	`18`	`kind = "malloc"`
Original file line number	Diff line number	Diff line change
`@@ -27,7 +27,7 @@ class MyTest2Class`
`27`	`27`
`28`	`28`	`int ptr_d = (int )malloc(sizeof(int));`
`29`	`29`	`d = new(ptr_d) int;`
`30`		`- free(d); // GOOD [FALSE POSITIVE]`
	`30`	`+ free(d); // GOOD`
`31`	`31`	`}`
`32`	`32`
`33`	`33`	`int c, d;`