================
@@ -0,0 +1,72 @@
+.. title:: clang-tidy - bugprone-conflicting-global-accesses
+
+bugprone-conflicting-global-accesses
+====================================
+
+Finds conflicting accesses on global variables.
+
+Modifying twice or reading and modifying a memory location without a
+defined sequence of the operations is either undefined behavior or has
+unspecified order. This checker is similar to the -Wunsequenced clang warning,
+however it only looks at global variables and therefore can find conflicting
+actions recursively inside functions as well.
+
+For example::
+
+ int a = 0;
+ int b = (a++) - a; // This is flagged by -Wunsequenced.
+
+However global variables allow for more complex scenarios that
+-Wunsequenced doesn't detect. E.g. ::
+
+ int globalVar = 0;
+
+ int incFun() {
+ globalVar++;
+ return globalVar;
+ }
+
+ int main() {
+ return globalVar + incFun(); // This is not detected by -Wunsequenced.
+ }
+
+This checker attempts to detect such cases. It recurses into functions that are
+inside the same translation unit. It also attempts not to flag cases that are
+already covered by -Wunsequenced. Global unions and structs are also handled.
+For example::
+
+ typedef struct {
+ int A;
+ float B;
+ } IntAndFloat;
+
+ IntAndFloat GlobalIF;
+
+ int globalIFGetSum() {
+ int sum = GlobalIF.A + (int)GlobalIF.B;
+ GlobalIF = (IntAndFloat){};
+ return sum;
+ }
+
+ int main() {
+ // The following printf could give different results on different
+ // compilers.
+ printf("sum: %i, int: %i", globalIFGetSum(), GlobalIF.A);
+ }
+
+Options
+-------
+
+.. option:: HandleMutableFunctionParametersAsWrites
+
+ It's possible to enable handling mutable reference and pointer function
+ parameters as writes using the HandleMutableFunctionParametersAsWrites
+ option. For example:
+
+ void func(int& a);
+
+ int globalVar;
+ func(globalVar); // <- this could be a write to globalVar.
+
+ This option is disabled by default.
----------------
vbvictor wrote:
```suggestion
Default value is `false`.
```
https://github.com/llvm/llvm-project/pull/130421
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