[clang] [NFC][analyzer] OOB test consolidation II: constraint checking (PR #126748)
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Tue Feb 11 07:48:23 PST 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-clang-static-analyzer-1
Author: Donát Nagy (NagyDonat)
<details>
<summary>Changes</summary>
This commit heavily refactors `out-of-bounds-constraint-check.c`:
1. The complex combinations of several `clang_analyzer_eval` calls were replaced by `clang_analyzer_value`, which can directly query the range of a symbol.
2. Testcases were renamed to a (hopefully) more consistent scheme.
3. The use of `size_t` as an argument type was replaced by `unsigned long long`, which is usually a no-op, but seems to be a better choice if I look for `64u` in the output of `clang_analyzer_value`.
4. The single "dynamic extent" case was generalized into a full set of tests that use `malloc`.
5. Half of the testcases (the ones that don't use `malloc`) were changed to use an `int[5]` array instead of a string literal. After this change the tests in this file cover every functionality that was tested by the testcases `test_assume_after_access{,2}` in the file `out-of-bounds.c` so I was able to delete those two testcases (and therefore consolidate the validation of these constraints within a single test file).
This is the second commit in a series that reorganizes the tests of `security.ArrayBound` to system that's easier to understand and maintain. (Note that this file wasn't significantly modified by the recent commit 6e17ed9b04e5523cc910bf171c3122dcc64b86db which renamed `alpha.security.ArrayBoundV2` to `security.ArrayBound`; but I still felt that this cleanup may be useful.)
---
Full diff: https://github.com/llvm/llvm-project/pull/126748.diff
2 Files Affected:
- (modified) clang/test/Analysis/out-of-bounds-constraint-check.c (+155-104)
- (modified) clang/test/Analysis/out-of-bounds.c (+1-15)
``````````diff
diff --git a/clang/test/Analysis/out-of-bounds-constraint-check.c b/clang/test/Analysis/out-of-bounds-constraint-check.c
index df48c8c1707138..b89af08cff2229 100644
--- a/clang/test/Analysis/out-of-bounds-constraint-check.c
+++ b/clang/test/Analysis/out-of-bounds-constraint-check.c
@@ -1,112 +1,163 @@
// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix.Malloc,security.ArrayBound,debug.ExprInspection \
// RUN: -analyzer-config eagerly-assume=false -verify %s
-void clang_analyzer_eval(int);
-void clang_analyzer_printState(void);
-
-typedef typeof(sizeof(int)) size_t;
-const char a[] = "abcd"; // extent: 5 bytes
-
-void symbolic_size_t_and_int0(size_t len) {
- (void)a[len + 1]; // no-warning
- // We infered that the 'len' must be in a specific range to make the previous indexing valid.
- // len: [0,3]
- clang_analyzer_eval(len <= 3); // expected-warning {{TRUE}}
- clang_analyzer_eval(len <= 2); // expected-warning {{UNKNOWN}}
-}
-
-void symbolic_size_t_and_int1(size_t len) {
- (void)a[len]; // no-warning
- // len: [0,4]
- clang_analyzer_eval(len <= 4); // expected-warning {{TRUE}}
- clang_analyzer_eval(len <= 3); // expected-warning {{UNKNOWN}}
-}
-
-void symbolic_size_t_and_int2(size_t len) {
- (void)a[len - 1]; // no-warning
- // len: [1,5]
- clang_analyzer_eval(1 <= len && len <= 5); // expected-warning {{TRUE}}
- clang_analyzer_eval(2 <= len); // expected-warning {{UNKNOWN}}
- clang_analyzer_eval(len <= 4); // expected-warning {{UNKNOWN}}
-}
-
-void symbolic_uint_and_int0(unsigned len) {
- (void)a[len + 1]; // no-warning
- // len: [0,3]
- clang_analyzer_eval(0 <= len && len <= 3); // expected-warning {{TRUE}}
- clang_analyzer_eval(1 <= len); // expected-warning {{UNKNOWN}}
- clang_analyzer_eval(len <= 2); // expected-warning {{UNKNOWN}}
-}
-
-void symbolic_uint_and_int1(unsigned len) {
- (void)a[len]; // no-warning
- // len: [0,4]
- clang_analyzer_eval(0 <= len && len <= 4); // expected-warning {{TRUE}}
- clang_analyzer_eval(1 <= len); // expected-warning {{UNKNOWN}}
- clang_analyzer_eval(len <= 3); // expected-warning {{UNKNOWN}}
-}
-void symbolic_uint_and_int2(unsigned len) {
- (void)a[len - 1]; // no-warning
- // len: [1,5]
- clang_analyzer_eval(1 <= len && len <= 5); // expected-warning {{TRUE}}
- clang_analyzer_eval(2 <= len); // expected-warning {{UNKNOWN}}
- clang_analyzer_eval(len <= 4); // expected-warning {{UNKNOWN}}
-}
-
-void symbolic_int_and_int0(int len) {
- (void)a[len + 1]; // no-warning
- // len: [-1,3]
- clang_analyzer_eval(-1 <= len && len <= 3); // expected-warning {{TRUE}}
- clang_analyzer_eval(0 <= len); // expected-warning {{UNKNOWN}}
- clang_analyzer_eval(len <= 2); // expected-warning {{UNKNOWN}}
-}
-void symbolic_int_and_int1(int len) {
- (void)a[len]; // no-warning
- // len: [0,4]
- clang_analyzer_eval(0 <= len && len <= 4); // expected-warning {{TRUE}}
- clang_analyzer_eval(1 <= len); // expected-warning {{UNKNOWN}}
- clang_analyzer_eval(len <= 3); // expected-warning {{UNKNOWN}}
-}
-void symbolic_int_and_int2(int len) {
- (void)a[len - 1]; // no-warning
- // len: [1,5]
- clang_analyzer_eval(1 <= len && len <= 5); // expected-warning {{TRUE}}
- clang_analyzer_eval(2 <= len); // expected-warning {{UNKNOWN}}
- clang_analyzer_eval(len <= 4); // expected-warning {{UNKNOWN}}
-}
-
-void symbolic_longlong_and_int0(long long len) {
- (void)a[len + 1]; // no-warning
- // len: [-1,3]
- clang_analyzer_eval(-1 <= len && len <= 3); // expected-warning {{TRUE}}
- clang_analyzer_eval(0 <= len); // expected-warning {{UNKNOWN}}
- clang_analyzer_eval(len <= 2); // expected-warning {{UNKNOWN}}
+// When the checker security.ArrayBound encounters an array subscript operation
+// that _may be_ in bounds, it assumes that indexing _is_ in bound. This test
+// file validates these assumptions.
+
+void clang_analyzer_value(int);
+
+// Simple case: memory area with a static extent.
+
+int FiveInts[5] = {1, 2, 3, 4, 5};
+
+void int_plus_one(int len) {
+ (void)FiveInts[len + 1]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32s:{ [-1, 3] }}}
+}
+
+void int_neutral(int len) {
+ (void)FiveInts[len]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32s:{ [0, 4] }}}
+}
+
+void int_minus_one(int len) {
+ (void)FiveInts[len - 1]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32s:{ [1, 5] }}}
+}
+
+void unsigned_plus_one(unsigned len) {
+ (void)FiveInts[len + 1]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32u:{ [0, 3] }}}
+}
+
+void unsigned_neutral(unsigned len) {
+ (void)FiveInts[len]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32u:{ [0, 4] }}}
+}
+
+void unsigned_minus_one(unsigned len) {
+ (void)FiveInts[len - 1]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32u:{ [1, 5] }}}
+}
+
+void ll_plus_one(long long len) {
+ (void)FiveInts[len + 1]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64s:{ [-1, 3] }}}
+}
+
+void ll_neutral(long long len) {
+ (void)FiveInts[len]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64s:{ [0, 4] }}}
+}
+
+void ll_minus_one(long long len) {
+ (void)FiveInts[len - 1]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64s:{ [1, 5] }}}
+}
+
+void ull_plus_one(unsigned long long len) {
+ (void)FiveInts[len + 1]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64u:{ [0, 3] }}}
+}
+
+void ull_neutral(unsigned long long len) {
+ (void)FiveInts[len]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64u:{ [0, 4] }}}
+}
+
+void ull_minus_one(unsigned long long len) {
+ (void)FiveInts[len - 1]; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64u:{ [1, 5] }}}
}
+// Also try the same with a dynamically allocated memory block, because in the
+// past there were issues with the type/signedness of dynamic extent symbols.
+
+typedef __typeof(sizeof(int)) size_t;
void *malloc(size_t);
void free(void *);
-void symbolic_longlong_and_int0_dynamic_extent(long long len) {
- char *b = malloc(5);
- (void)b[len + 1]; // no-warning
- // len: [-1,3]
- clang_analyzer_eval(-1 <= len && len <= 3); // expected-warning {{TRUE}}
- clang_analyzer_eval(0 <= len); // expected-warning {{UNKNOWN}}
- clang_analyzer_eval(len <= 2); // expected-warning {{UNKNOWN}}
- free(b);
-}
-
-void symbolic_longlong_and_int1(long long len) {
- (void)a[len]; // no-warning
- // len: [0,4]
- clang_analyzer_eval(0 <= len && len <= 4); // expected-warning {{TRUE}}
- clang_analyzer_eval(1 <= len); // expected-warning {{UNKNOWN}}
- clang_analyzer_eval(len <= 3); // expected-warning {{UNKNOWN}}
-}
-
-void symbolic_longlong_and_int2(long long len) {
- (void)a[len - 1]; // no-warning
- // len: [1,5]
- clang_analyzer_eval(1 <= len && len <= 5); // expected-warning {{TRUE}}
- clang_analyzer_eval(2 <= len); // expected-warning {{UNKNOWN}}
- clang_analyzer_eval(len <= 4); // expected-warning {{UNKNOWN}}
+
+void dyn_int_plus_one(int len) {
+ char *p = malloc(5);
+ p[len + 1] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32s:{ [-1, 3] }}}
+ free(p);
+}
+
+void dyn_int_neutral(int len) {
+ char *p = malloc(5);
+ p[len] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32s:{ [0, 4] }}}
+ free(p);
+}
+
+void dyn_int_minus_one(int len) {
+ char *p = malloc(5);
+ p[len - 1] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32s:{ [1, 5] }}}
+ free(p);
+}
+
+void dyn_unsigned_plus_one(unsigned len) {
+ char *p = malloc(5);
+ p[len + 1] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32u:{ [0, 3] }}}
+ free(p);
+}
+
+void dyn_unsigned_neutral(unsigned len) {
+ char *p = malloc(5);
+ p[len] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32u:{ [0, 4] }}}
+ free(p);
+}
+
+void dyn_unsigned_minus_one(unsigned len) {
+ char *p = malloc(5);
+ p[len - 1] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{32u:{ [1, 5] }}}
+ free(p);
+}
+
+void dyn_ll_plus_one(long long len) {
+ char *p = malloc(5);
+ p[len + 1] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64s:{ [-1, 3] }}}
+ free(p);
+}
+
+void dyn_ll_neutral(long long len) {
+ char *p = malloc(5);
+ p[len] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64s:{ [0, 4] }}}
+ free(p);
+}
+
+void dyn_ll_minus_one(long long len) {
+ char *p = malloc(5);
+ p[len - 1] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64s:{ [1, 5] }}}
+ free(p);
+}
+
+void dyn_ull_plus_one(unsigned long long len) {
+ char *p = malloc(5);
+ p[len + 1] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64u:{ [0, 3] }}}
+ free(p);
+}
+
+void dyn_ull_neutral(unsigned long long len) {
+ char *p = malloc(5);
+ p[len] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64u:{ [0, 4] }}}
+ free(p);
+}
+
+void dyn_ull_minus_one(unsigned long long len) {
+ char *p = malloc(5);
+ p[len - 1] = 1; // no-warning
+ clang_analyzer_value(len); // expected-warning {{64u:{ [1, 5] }}}
+ free(p);
}
diff --git a/clang/test/Analysis/out-of-bounds.c b/clang/test/Analysis/out-of-bounds.c
index 923797200d0b40..9f410e884d7633 100644
--- a/clang/test/Analysis/out-of-bounds.c
+++ b/clang/test/Analysis/out-of-bounds.c
@@ -1,6 +1,4 @@
-// RUN: %clang_analyze_cc1 -Wno-array-bounds -analyzer-checker=core,security.ArrayBound,debug.ExprInspection -verify %s
-
-void clang_analyzer_eval(int);
+// RUN: %clang_analyze_cc1 -Wno-array-bounds -analyzer-checker=core,security.ArrayBound -verify %s
// Tests doing an out-of-bounds access after the end of an array using:
// - constant integer index
@@ -142,12 +140,6 @@ void test4(int x) {
buf[x] = 1; // expected-warning{{Out of bound access to memory}}
}
-void test_assume_after_access(unsigned long x) {
- int buf[100];
- buf[x] = 1;
- clang_analyzer_eval(x <= 99); // expected-warning{{TRUE}}
-}
-
// Don't warn when indexing below the start of a symbolic region's whose
// base extent we don't know.
int *get_symbolic(void);
@@ -180,12 +172,6 @@ void test_extern_void(void) {
p[1] = 42; // no-warning
}
-void test_assume_after_access2(unsigned long x) {
- char buf[100];
- buf[x] = 1;
- clang_analyzer_eval(x <= 99); // expected-warning{{TRUE}}
-}
-
struct incomplete;
char test_comparison_with_extent_symbol(struct incomplete *p) {
// Previously this was reported as a (false positive) overflow error because
``````````
</details>
https://github.com/llvm/llvm-project/pull/126748
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