From 93eb87007a2c4f71357a8132dabe4b03647ca227 Mon Sep 17 00:00:00 2001
From: zijunzhao <zijunzhao@google.com>
Date: Tue, 31 Jan 2023 00:34:59 +0000
Subject: [PATCH] Add BIONIC_COMPLICATED_NULLNESS as _Null_unspecified

In some cases, the nullability of the pointer argument is too
complicated. Developers have better check relevant manuals or
code before annotating.

Bugs: b/245972273
Test: None
Change-Id: I3589a5080b267d1766cc8ed99868129ac16e4012
---
 libc/include/fcntl.h     | 2 +-
 libc/include/regex.h     | 4 ++--
 libc/include/sys/cdefs.h | 8 ++++++++
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/libc/include/fcntl.h b/libc/include/fcntl.h
index 4ef894b87..1ec932bd9 100644
--- a/libc/include/fcntl.h
+++ b/libc/include/fcntl.h
@@ -149,7 +149,7 @@ int open64(const char* _Nonnull __path, int __flags, ...) __INTRODUCED_IN(21);
  *
  * Available since API level 21.
  */
-ssize_t splice(int __in_fd, off64_t* _Null_unspecified __in_offset, int __out_fd, off64_t* _Null_unspecified __out_offset, size_t __length, unsigned int __flags) __INTRODUCED_IN(21);
+ssize_t splice(int __in_fd, off64_t* __BIONIC_COMPLICATED_NULLNESS __in_offset, int __out_fd, off64_t* __BIONIC_COMPLICATED_NULLNESS __out_offset, size_t __length, unsigned int __flags) __INTRODUCED_IN(21);
 
 /**
  * [tee(2)](http://man7.org/linux/man-pages/man2/tee.2.html)
diff --git a/libc/include/regex.h b/libc/include/regex.h
index be1418efe..be33819cd 100644
--- a/libc/include/regex.h
+++ b/libc/include/regex.h
@@ -49,8 +49,8 @@ typedef ssize_t regoff_t;
 typedef struct {
 	int re_magic;
 	size_t re_nsub;		/* number of parenthesized subexpressions */
-	const char * _Null_unspecified re_endp;	/* end pointer for REG_PEND */
-	struct re_guts * _Null_unspecified re_g;	/* none of your business :-) */
+	const char * __BIONIC_COMPLICATED_NULLNESS re_endp;	/* end pointer for REG_PEND */
+	struct re_guts * __BIONIC_COMPLICATED_NULLNESS re_g;	/* none of your business :-) */
 } regex_t;
 
 typedef struct {
diff --git a/libc/include/sys/cdefs.h b/libc/include/sys/cdefs.h
index 5b9d99b3a..484757e26 100644
--- a/libc/include/sys/cdefs.h
+++ b/libc/include/sys/cdefs.h
@@ -62,6 +62,14 @@
 
 #define __BIONIC_ALIGN(__value, __alignment) (((__value) + (__alignment)-1) & ~((__alignment)-1))
 
+/*
+ * The nullness constraints of this parameter or return value are
+ * quite complex. This is used to highlight spots where developers
+ * are encouraged to read relevant manuals or code to understand
+ * the full picture of nullness for this pointer.
+ */
+#define __BIONIC_COMPLICATED_NULLNESS _Null_unspecified
+
 /*
  * The __CONCAT macro is used to concatenate parts of symbol names, e.g.
  * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo.