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Update EXP43-C to use new dataflow. #1204

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250d4e3
Update EXP43-C to use new dataflow.
MichaelRFairhurst Oct 1, 2026
fc82f86
Merge remote-tracking branch 'origin/main' into michaelrfairhurst/upd…
MichaelRFairhurst Oct 1, 2026
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2 changes: 1 addition & 1 deletion c/cert/src/rules/EXP43-C/RestrictPointerReferencesOverlappingObject.ql
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Expand Up @@ -16,7 +16,7 @@
*/

import cpp
import semmle.code.cpp.dataflow.DataFlow
import semmle.code.cpp.dataflow.new.DataFlow
import semmle.code.cpp.controlflow.Dominance
import codingstandards.c.cert
import codingstandards.cpp.Variable
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28 changes: 12 additions & 16 deletions c/cert/test/rules/EXP43-C/RestrictPointerReferencesOverlappingObject.expected
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@@ -1,16 +1,12 @@
WARNING: module 'DataFlow' has been deprecated and may be removed in future (RestrictPointerReferencesOverlappingObject.ql:47,57-65)
WARNING: module 'DataFlow' has been deprecated and may be removed in future (RestrictPointerReferencesOverlappingObject.ql:48,22-30)
WARNING: module 'DataFlow' has been deprecated and may be removed in future (RestrictPointerReferencesOverlappingObject.ql:52,20-28)
WARNING: module 'DataFlow' has been deprecated and may be removed in future (RestrictPointerReferencesOverlappingObject.ql:58,3-11)
WARNING: module 'DataFlow' has been deprecated and may be removed in future (RestrictPointerReferencesOverlappingObject.ql:61,58-66)
WARNING: module 'DataFlow' has been deprecated and may be removed in future (RestrictPointerReferencesOverlappingObject.ql:77,64-72)
WARNING: module 'DataFlow' has been deprecated and may be removed in future (RestrictPointerReferencesOverlappingObject.ql:78,64-72)
| test.c:18:22:18:23 | i2 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:18:17:18:18 | i3 | i3 | test.c:18:22:18:23 | i2 | the object pointed to by i2 |
| test.c:19:8:19:9 | g2 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:5:15:5:16 | g1 | g1 | test.c:19:8:19:9 | g2 | the object pointed to by g2 |
| test.c:20:8:20:9 | i2 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:16:17:16:18 | i1 | i1 | test.c:20:8:20:9 | i2 | the object pointed to by i2 |
| test.c:27:10:27:11 | g1 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:23:19:23:20 | i5 | i5 | test.c:19:8:19:9 | g2 | the same source value |
| test.c:28:10:28:11 | g1 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:22:19:22:20 | i4 | i4 | test.c:19:8:19:9 | g2 | the same source value |
| test.c:39:22:39:26 | & ... | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:39:17:39:18 | px | px | test.c:38:28:38:30 | & ... | v1 via address-of |
| test.c:45:10:45:14 | & ... | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:42:19:42:20 | pz | pz | test.c:43:10:43:14 | & ... | v1 via address-of |
| test.c:46:10:46:14 | & ... | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:41:19:41:20 | py | py | test.c:43:10:43:14 | & ... | v1 via address-of |
| test.c:46:10:46:14 | & ... | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:41:19:41:20 | py | py | test.c:45:10:45:14 | & ... | v1 via address-of |
| test.c:15:22:15:23 | i2 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:15:17:15:18 | i3 | i3 | test.c:15:22:15:23 | i2 | the object pointed to by i2 |
| test.c:34:22:34:23 | g4 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:34:17:34:18 | i2 | i2 | test.c:34:22:34:23 | g4 | the same source value |
| test.c:35:8:35:9 | g4 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:18:15:18:16 | g3 | g3 | test.c:35:8:35:9 | g4 | the object pointed to by g4 |
| test.c:49:10:49:11 | g5 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:45:19:45:20 | i5 | i5 | test.c:41:22:41:23 | g5 | the same source value |
| test.c:49:10:49:11 | g5 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:45:19:45:20 | i5 | i5 | test.c:47:10:47:11 | g5 | the same source value |
Comment on lines +4 to +5
| test.c:50:10:50:11 | g5 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:44:19:44:20 | i4 | i4 | test.c:41:22:41:23 | g5 | the same source value |
| test.c:50:10:50:11 | g5 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:44:19:44:20 | i4 | i4 | test.c:47:10:47:11 | g5 | the same source value |
| test.c:50:10:50:11 | g5 | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:44:19:44:20 | i4 | i4 | test.c:49:10:49:11 | g5 | the same source value |
| test.c:63:22:63:26 | & ... | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:63:17:63:18 | px | px | test.c:62:28:62:30 | & ... | v1 via address-of |
| test.c:69:10:69:14 | & ... | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:66:19:66:20 | pz | pz | test.c:67:10:67:14 | & ... | v1 via address-of |
| test.c:70:10:70:14 | & ... | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:65:19:65:20 | py | py | test.c:67:10:67:14 | & ... | v1 via address-of |
| test.c:70:10:70:14 | & ... | Assignment to restrict-qualified pointer $@ results in pointers aliasing $@. | test.c:65:19:65:20 | py | py | test.c:69:10:69:14 | & ... | v1 via address-of |
50 changes: 37 additions & 13 deletions c/cert/test/rules/EXP43-C/test.c
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Expand Up @@ -2,35 +2,59 @@
#include <stdio.h>
#include <string.h>

int *restrict g1;
int *restrict g2;
int *restrict g1_1;
int *g2_1;

struct s1 {
int x, y, z;
};
struct s1 v1;

void test_global_local() {
int *restrict g1;
int *restrict g2;
void test_global_local_1() {
int *restrict i1 = g1; // COMPLIANT
int *restrict i2 = g2; // COMPLIANT
int *restrict i3 = i2; // NON_COMPLIANT
g1 = g2; // NON_COMPLIANT
i1 = i2; // NON_COMPLIANT
}

int *restrict g3;
int *restrict g4;
void test_global_local_2() {
// The second assignment in this block is non-compliant for subtle reasons.
//
// If we assume that `test_global_local_2` is only called once, then `g3` and
// `g4` will likely point to different values and therefore `i1` and `i2` do
// not alias each other. from g3 to g4 is too late to cause an issue. This was
// how this query worked under the old dataflow library.
//
// However, if we assume this function is called more than once, then the
// assignment that causes `g3` and `g4` to have the same value, at the end of
// this function, can predate the assignments that initialize `i1` and `i2`
// within this function, leading to aliasing that violates the rule. This is
// how the new dataflow library handles this case.
int *restrict i1 = g3; // COMPLIANT
int *restrict i2 = g4; // NON_COMPLIANT
g3 = g4; // NON_COMPLIANT
}

int *restrict g5;
int *restrict g6;
void test_global_local_3() {
int *restrict i2 = g5; // COMPLIANT
int *restrict i3 = g6; // COMPLIANT
{
int *restrict i4;
int *restrict i5;
int *restrict i6;
i4 = g1; // COMPLIANT
i4 = g5; // COMPLIANT -- first assignment within this block
i4 = (void *)0; // COMPLIANT
i5 = g1; // NON_COMPLIANT - block rather than statement scope matters
i4 = g1; // NON_COMPLIANT
i6 = g2; // COMPLIANT
i5 = g5; // NON_COMPLIANT - block rather than statement scope matters
i4 = g5; // NON_COMPLIANT
i6 = g6; // COMPLIANT -- first assignment within this block
}
}

void test_global_local_1() {
int *restrict g1_1;
int *g2_1;
void test_global_local_4() {
g1_1 = g2_1; // COMPLIANT
}

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2 changes: 2 additions & 0 deletions change_notes/2026-10-01-use-new-dataflow-in-exp43-c.md
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- `EXP43-C` - `RestrictPointerReferencesOverlappingObject.ql`:
- Updated to use the new dataflow library for tracking assignments to restrict-qualified pointers. Using the new dataflow library may introduce a different set of false positives and false negatives compared to the previous implementation, though it has higher precision overall.
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