[-Wunsafe-buffer-usage] Emit fixits for arguments of function pointers calls

Currently we ignore calls on function pointers (unlike direct calls of
functions and class methods). This patch adds support for function pointers as
well.

The change is to simply replace use of forEachArgumentWithParam matcher in UPC
gadget with forEachArgumentWithParamType.

from the documentation of forEachArgumentWithParamType:
/// Matches all arguments and their respective types for a \c CallExpr or
/// \c CXXConstructExpr. It is very similar to \c forEachArgumentWithParam but
/// it works on calls through function pointers as well.

Currently the matcher also uses hasPointerType() which checks that the
canonical type of an argument is pointer and won't match on arrays decayed to
pointer. Replacing hasPointerType() with isAnyPointerType() which allows
implicit casts allows for the arrays to be matched as well and this way we get
fixits for array arguments to function pointer calls too.

Author: jkorous-apple

clang/lib/Analysis/UnsafeBufferUsage.cpp

@@ -282,8 +282,8 @@ isInUnspecifiedPointerContext(internal::Matcher<Stmt> InnerMatcher) {
   //    (i.e., computing the distance between two pointers); or ...
 
   auto CallArgMatcher =
-      callExpr(forEachArgumentWithParam(InnerMatcher,
-                  hasPointerType() /* array also decays to pointer type*/),
+      callExpr(forEachArgumentWithParamType(InnerMatcher,
+                  isAnyPointer() /* array also decays to pointer type*/),
           unless(callee(functionDecl(hasAttr(attr::UnsafeBufferUsage)))));
 
   auto CastOperandMatcher =

clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-pointer-arg-to-func-ptr-call.cpp

@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -std=c++20 -Wunsafe-buffer-usage \
+// RUN:            -fsafe-buffer-usage-suggestions \
+// RUN:            -fdiagnostics-parseable-fixits %s 2>&1 | FileCheck %s
+
+void unsafe_array_func_ptr_call(void (*fn_ptr)(int *param)) {
+  int p[32];
+  // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:3-[[@LINE-1]]:12}:"std::array<int, 32> p"
+
+  int tmp = p[5];
+  fn_ptr(p);
+  // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:11}:".data()"
+}