[clang] allow use of ptrauth module from no_undeclared_includes system modules (PR #88432)

[Ian Anderson via cfe-commits]

https://github.com/ian-twilightcoder updated https://github.com/llvm/llvm-project/pull/88432

>From 88da8be7ed10f1ee8e7e992fdd59dce52456b2ce Mon Sep 17 00:00:00 2001
From: Alex Lorenz <arphaman at gmail.com>
Date: Thu, 9 Jul 2020 15:10:49 -0700
Subject: [PATCH] [modules] allow use of ptrauth module from
 no_undeclared_includes system modules

---
 clang/lib/Basic/Module.cpp                                | 4 ++++
 .../Inputs/ptrauth-include-from-darwin/module.modulemap   | 8 ++++++++
 .../Modules/Inputs/ptrauth-include-from-darwin/ptrauth.h  | 1 +
 .../Modules/Inputs/ptrauth-include-from-darwin/stddef.h   | 1 +
 clang/test/Modules/ptrauth-include-from-darwin.m          | 6 ++++++
 5 files changed, 20 insertions(+)
 create mode 100644 clang/test/Modules/Inputs/ptrauth-include-from-darwin/module.modulemap
 create mode 100644 clang/test/Modules/Inputs/ptrauth-include-from-darwin/ptrauth.h
 create mode 100644 clang/test/Modules/Inputs/ptrauth-include-from-darwin/stddef.h
 create mode 100644 clang/test/Modules/ptrauth-include-from-darwin.m

diff --git a/clang/lib/Basic/Module.cpp b/clang/lib/Basic/Module.cpp
index 256365d66bb907..bb212cde878826 100644
--- a/clang/lib/Basic/Module.cpp
+++ b/clang/lib/Basic/Module.cpp
@@ -305,6 +305,10 @@ bool Module::directlyUses(const Module *Requested) {
   if (Requested->fullModuleNameIs({"_Builtin_stddef", "max_align_t"}) ||
       Requested->fullModuleNameIs({"_Builtin_stddef_wint_t"}))
     return true;
+  // Darwin is allowed is to use our builtin 'ptrauth.h' and its accompanying
+  // module.
+  if (!Requested->Parent && Requested->Name == "ptrauth")
+    return true;
 
   if (NoUndeclaredIncludes)
     UndeclaredUses.insert(Requested);
diff --git a/clang/test/Modules/Inputs/ptrauth-include-from-darwin/module.modulemap b/clang/test/Modules/Inputs/ptrauth-include-from-darwin/module.modulemap
new file mode 100644
index 00000000000000..741b9bb1efc54d
--- /dev/null
+++ b/clang/test/Modules/Inputs/ptrauth-include-from-darwin/module.modulemap
@@ -0,0 +1,8 @@
+module libc [no_undeclared_includes] {
+  module stddef { header "stddef.h" export * }
+}
+
+module ptrauth {
+  header "ptrauth.h"
+  export *
+}
diff --git a/clang/test/Modules/Inputs/ptrauth-include-from-darwin/ptrauth.h b/clang/test/Modules/Inputs/ptrauth-include-from-darwin/ptrauth.h
new file mode 100644
index 00000000000000..c8620b64b2ceef
--- /dev/null
+++ b/clang/test/Modules/Inputs/ptrauth-include-from-darwin/ptrauth.h
@@ -0,0 +1 @@
+void foo();
diff --git a/clang/test/Modules/Inputs/ptrauth-include-from-darwin/stddef.h b/clang/test/Modules/Inputs/ptrauth-include-from-darwin/stddef.h
new file mode 100644
index 00000000000000..777a524fc67110
--- /dev/null
+++ b/clang/test/Modules/Inputs/ptrauth-include-from-darwin/stddef.h
@@ -0,0 +1 @@
+ at import ptrauth;
diff --git a/clang/test/Modules/ptrauth-include-from-darwin.m b/clang/test/Modules/ptrauth-include-from-darwin.m
new file mode 100644
index 00000000000000..72b0c36e7cb7d3
--- /dev/null
+++ b/clang/test/Modules/ptrauth-include-from-darwin.m
@@ -0,0 +1,6 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -I %S/Inputs/ptrauth-include-from-darwin %s -verify
+// expected-no-diagnostics
+
+ at import libc;
+void bar() { foo(); }