[cherry-pick stable/20230725] [Modules] no_undeclared_includes modules (Apple Darwin) don't work the clang modules

llvm#68241
rdar://105819340

Author: git apple-llvm automerger

clang/test/Modules/Inputs/System/usr/include/inttypes.h

@@ -1,24 +1,9 @@
 module cstd [system] {
-  // Only in system headers directory
-  module complex {
-    header "complex.h"
-  }
-
   // Only in compiler support directory
   module float_constants {
     header "float.h"
   }
 
-  // In both directories (compiler support version wins, forwards)
-  module inttypes {
-    header "inttypes.h"
-  }
-
-  // Only in system headers directory
-  module math {
-    header "math.h"
-  }
-
   // Only in system headers directory
   module stdio {
     header "stdio.h"

clang/test/Modules/Inputs/System/usr/include/math.h

@@ -1,36 +1 @@
-#ifndef STDINT_H
-#define STDINT_H
-
 typedef int my_awesome_nonstandard_integer_type;
-
-// types needed by stdatomic.h
-
-typedef char int_least8_t;
-typedef short int_least16_t;
-typedef int int_least32_t;
-typedef long long int int_least64_t;
-typedef unsigned char uint_least8_t;
-typedef unsigned short uint_least16_t;
-typedef unsigned int uint_least32_t;
-typedef unsigned long long uint_least64_t;
-
-typedef char int_fast8_t;
-typedef short int_fast16_t;
-typedef int int_fast32_t;
-typedef long long int int_fast64_t;
-typedef unsigned char uint_fast8_t;
-typedef unsigned short uint_fast16_t;
-typedef unsigned int uint_fast32_t;
-typedef unsigned long long uint_fast64_t;
-
-typedef int intptr_t;
-typedef unsigned int uintptr_t;
-typedef int intmax_t;
-typedef unsigned int uintmax_t;
-
-// additional types for unwind.h
-
-typedef unsigned int uint32_t;
-typedef unsigned long long uint64_t;
-
-#endif /* STDINT_H */

clang/test/Modules/Inputs/System/usr/include/module.map

@@ -0,0 +1,29 @@
+module c_complex [system] {
+  header "complex.h"
+  export *
+}
+
+module c_float [system] {
+  header "float.h"
+  export *
+}
+
+module c_inttypes [system] {
+  header "inttypes.h"
+  export *
+}
+
+module c_limits [system] {
+  header "limits.h"
+  export *
+}
+
+module c_math [system] {
+  header "math.h"
+  export *
+}
+
+module c_stdint [system] {
+  header "stdint.h"
+  export *
+}

clang/test/Modules/Inputs/System/usr/include/stdint.h

@@ -0,0 +1,4 @@
+module cpp_stdint [system] {
+  header "stdint.h"
+  export *
+}

clang/test/Modules/Inputs/builtin-headers/builtin-modules.modulemap

@@ -0,0 +1,6 @@
+#ifndef CPP_STDINT_H
+#define CPP_STDINT_H
+
+#include_next <stdint.h>
+
+#endif

clang/test/Modules/Inputs/builtin-headers/c++/module.modulemap

@@ -0,0 +1 @@
+// Required by tgmath.h

clang/test/Modules/Inputs/builtin-headers/c++/stdint.h

@@ -0,0 +1,12 @@
+#ifndef INTTYPES_H
+#define INTTYPES_H
+
+// This creates an include cycle when inttypes.h and stdint.h
+// are both part of the cstd module. This include will resolve
+// to the C++ stdint.h, which will #include_next eventually to
+// the stdint.h in this directory, and thus create the cycle
+// cstd (inttypes.h) -> cpp_stdint (stdint.h) -> cstd (stdint.h).
+// This cycle is worked around by cstd using [no_undeclared_includes].
+#include <stdint.h>
+
+#endif