[clang] [clang][analyzer] Add StoreToImmutable checker (PR #150417)

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+// RUN: %clang_analyze_cc1 -analyzer-checker=alpha.core.StoreToImmutable -verify %s
+
+// Test basic functionality of StoreToImmutable checker
+// This tests direct writes to immutable regions without function modeling
+
+// Direct write to a const global variable
+const int global_const = 42; // expected-note {{Memory region is in immutable space}}
+
+void test_direct_write_to_const_global() {
+  // This should trigger a warning about writing to immutable memory
+  *(int*)&global_const = 100; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write through a pointer to const memory
+void test_write_through_const_pointer() {
+  const int local_const = 10; // expected-note {{Memory region is in immutable space}}
+  int *ptr = (int*)&local_const;
+  *ptr = 20; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to string literal (should be in immutable space)
+void test_write_to_string_literal() {
+  char *str = (char*)"hello";
+  str[0] = 'H'; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to const array
+void test_write_to_const_array() {
+  const int arr[5] = {1, 2, 3, 4, 5};
+  int *ptr = (int*)arr;
+  ptr[0] = 10; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to const struct member
+struct TestStruct {
+  const int x; // expected-note 2{{Memory region is in immutable space}}
+  int y;
+};
+
+void test_write_to_const_struct_member() {
+  TestStruct s = {1, 2};
+  int *ptr = (int*)&s.x;
+  *ptr = 10; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to const global array
+const int global_array[3] = {1, 2, 3};
+
+void test_write_to_const_global_array() {
+  int *ptr = (int*)global_array;
+  ptr[0] = 10; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to const global struct
+const TestStruct global_struct = {1, 2};
+
+void test_write_to_const_global_struct() {
+  int *ptr = (int*)&global_struct.x;
+  *ptr = 10; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to const parameter
+void test_write_to_const_param(const int param) { // expected-note {{Memory region is in immutable space}}
+  *(int*)&param = 100; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to const reference parameter
+void test_write_to_const_ref_param(const int &param) {
+  *(int*)&param = 100; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to const pointer parameter
+void test_write_to_const_ptr_param(const int *param) {
+  *(int*)param = 100; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to const array parameter
+void test_write_to_const_array_param(const int arr[5]) {
+  *(int*)arr = 100; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to const struct parameter
+struct ParamStruct {
+  const int z; // expected-note 3{{Memory region is in immutable space}}
+  int w;
+};
+
+void test_write_to_const_struct_param(const ParamStruct s) {
+  *(int*)&s.z = 100; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to const struct reference parameter
+void test_write_to_const_struct_ref_param(const ParamStruct &s) {
+  *(int*)&s.z = 100; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+// Write to const struct pointer parameter
+void test_write_to_const_struct_ptr_param(const ParamStruct *s) {
+  *(int*)&s->z = 100; // expected-warning {{Writing to immutable memory is undefined behavior}}
+  // expected-note at -1 {{Writing to immutable memory is undefined behavior. This memory region is marked as immutable and should not be modified}}
+}
+
+//===--- NEGATIVE TEST CASES ---===//
+// These tests should NOT trigger warnings
+
+// Write to non-const variable (should not warn)
+void test_write_to_nonconst() {
+  int non_const = 42;
+  *(int*)&non_const = 100; // No warning expected
+}
+
+// Write to non-const global variable (should not warn)
+int global_non_const = 42;
+
+void test_write_to_nonconst_global() {
+  *(int*)&global_non_const = 100; // No warning expected
+}
+
+// Write to non-const struct member (should not warn)
+struct NonConstStruct {
+  int x;
+  int y;
+};
+
+void test_write_to_nonconst_struct_member() {
+  NonConstStruct s = {1, 2};
+  *(int*)&s.x = 100; // No warning expected
+}
+
+// Write to non-const parameter (should not warn)
+void test_write_to_nonconst_param(int param) {
+  *(int*)&param = 100; // No warning expected
+}
+
+// Normal assignment to non-const variable (should not warn)
+void test_normal_assignment() {
+  int x = 42;
+  x = 100; // No warning expected
+}
+
+// Write to non-const data through const pointer (should not warn - underlying memory is non-const)
+void test_const_ptr_to_nonconst_data() {
+  int data = 42;
+  const int *ptr = &data;
+  *(int*)ptr = 100; // No warning expected
+}
+
+// Write to non-const data through const reference (should not warn - underlying memory is non-const)
+void test_const_ref_to_nonconst_data() {
+  int data = 42;
+  const int &ref = data;
+  *(int*)&ref = 100; // No warning expected
+} 
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gamesh411 wrote:

Nice, I have added these cases.

https://github.com/llvm/llvm-project/pull/150417