libcpp: Diagnose __has_include outside of preprocessor directives [PR93545]

The standard says http://eel.is/c++draft/cpp.cond#7.sentence-2 that
__has_include can't appear at arbitrary places in the source.  As we have
not recognized __has_include* outside of preprocessing directives in the
past, accepting it there now would be a regression.  The patch does still
allow it in #define if it is then used in preprocessing directives, I guess
that use isn't strictly valid either, but clang seems to accept it.

2020-02-04  Jakub Jelinek  <jakub@redhat.com>

	* macro.c (builtin_has_include): Diagnose __has_include* use outside
	of preprocessing directives.

	* c-c++-common/cpp/has-include-1.c: New test.
	* c-c++-common/cpp/has-include-next-1.c: New test.
	* c-c++-common/gomp/has-include-1.c: New test.

2 files changed, 208 insertions, 0 deletions

diff --git a/gcc/testsuite/c-c++-common/cpp/has-include-1.c b/gcc/testsuite/c-c++-common/cpp/has-include-1.c
new file mode 100644
index 00000000000..1d9f011cba0
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/cpp/has-include-1.c
@@ -0,0 +1,104 @@
+/* { dg-do preprocess } */
+
+#if __has_include ("stdlib.h")
+#else
+#error error 1
+#endif
+#if __has_include (<stdlib.h>)
+#else
+#error error 2
+#endif
+#if !__has_include ("stdlib.h")
+#error error 3
+#elif !__has_include (<stdlib.h>)
+#error error 4
+#endif
+#if __has_include ("stdlib.h") && __has_include (<stdlib.h>)
+#else
+#error error 5
+#endif
+#if !defined(__has_include)
+#error error 6
+#endif
+#ifndef __has_include
+#error error 7
+#endif
+#ifdef __has_include
+#else
+#error error 8
+#endif
+#define m1 __has_include("stdlib.h")
+#define m2 ("stdlib.h")
+#define m3 ("has-include-1-nonexistent.h")
+#define m4 has-include-1-nonexistent-2.h>)
+#define m5 <stdlib.h>
+#if !m1
+#error error 9
+#endif
+#if !__has_include m2
+#error error 10
+#endif
+#if __has_include m3
+#error error 11
+#endif
+#if __has_include (<m4
+#error error 12
+#endif
+#if !__has_include (m5)
+#error error 13
+#endif
+__has_include (<stdlib.h>)		/* { dg-error "used outside of preprocessing directive" } */
+m1					/* { dg-error "used outside of preprocessing directive" } */
+#if 1
+m1					/* { dg-error "used outside of preprocessing directive" } */
+#endif
+#if 0
+#elif 1
+m1					/* { dg-error "used outside of preprocessing directive" } */
+#endif
+#if 0
+m1
+#endif
+#if 0
+#elif 0
+m1
+#endif
+#if __has_include "stdlib.h")		/* { dg-error "missing" } */
+#endif
+#if __has_include (stdlib.h)		/* { dg-error "operator|missing" } */
+#endif
+#if __has_include ()			/* { dg-error "operator|missing" } */
+#endif
+#if __has_include )			/* { dg-error "operator|missing" } */
+#endif
+#if __has_include ("stdlib.h)
+#endif
+/* { dg-error "operator|missing\[^\n\r]*after" "" { target *-*-* } .-2 } */
+/* { dg-warning "missing terminating" "" { target *-*-* } .-3 } */
+#if __has_include (stdlib.h>)		/* { dg-error "operator|missing" } */
+#endif
+#if __has_include ("stdlib.h"		/* { dg-error "missing" } */
+#endif
+#if __has_include (			/* { dg-error "operator|missing" } */
+#endif
+#if __has_include			/* { dg-error "operator|missing" } */
+#endif
+#if __has_include"stdlib.h"		/* { dg-error "missing" } */
+#endif
+#if __has_include'h'			/* { dg-error "operator|missing" } */
+#endif
+#if __has_include('h'			/* { dg-error "operator|missing" } */
+#endif
+#if __has_include('h')			/* { dg-error "operator" } */
+#endif
+#define H(h) __has_include(h)
+#if H(<stdlib.h>)
+#else
+#error error 14
+#endif
+void
+foo ()
+{
+#pragma omp parallel if (__has_include ("<stdlib.h>"))
+  ;
+}
diff --git a/gcc/testsuite/c-c++-common/cpp/has-include-next-1.c b/gcc/testsuite/c-c++-common/cpp/has-include-next-1.c
new file mode 100644
index 00000000000..79e528da667
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/cpp/has-include-next-1.c
@@ -0,0 +1,104 @@
+/* { dg-do preprocess } */
+
+#if __has_include_next ("stdlib.h")
+#else
+#error error 1
+#endif
+#if __has_include_next (<stdlib.h>)
+#else
+#error error 2
+#endif
+#if !__has_include_next ("stdlib.h")
+#error error 3
+#elif !__has_include_next (<stdlib.h>)
+#error error 4
+#endif
+#if __has_include_next ("stdlib.h") && __has_include_next (<stdlib.h>)
+#else
+#error error 5
+#endif
+#if !defined(__has_include_next)
+#error error 6
+#endif
+#ifndef __has_include_next
+#error error 7
+#endif
+#ifdef __has_include_next
+#else
+#error error 8
+#endif
+#define m1 __has_include_next("stdlib.h")
+#define m2 ("stdlib.h")
+#define m3 ("has-include-1-nonexistent.h")
+#define m4 has-include-1-nonexistent-2.h>)
+#define m5 <stdlib.h>
+#if !m1
+#error error 9
+#endif
+#if !__has_include_next m2
+#error error 10
+#endif
+#if __has_include_next m3
+#error error 11
+#endif
+#if __has_include_next (<m4
+#error error 12
+#endif
+#if !__has_include_next (m5)
+#error error 13
+#endif
+__has_include_next (<stdlib.h>)		/* { dg-error "used outside of preprocessing directive" } */
+m1					/* { dg-error "used outside of preprocessing directive" } */
+#if 1
+m1					/* { dg-error "used outside of preprocessing directive" } */
+#endif
+#if 0
+#elif 1
+m1					/* { dg-error "used outside of preprocessing directive" } */
+#endif
+#if 0
+m1
+#endif
+#if 0
+#elif 0
+m1
+#endif
+#if __has_include_next "stdlib.h")	/* { dg-error "missing" } */
+#endif
+#if __has_include_next (stdlib.h)	/* { dg-error "operator|missing" } */
+#endif
+#if __has_include_next ()		/* { dg-error "operator|missing" } */
+#endif
+#if __has_include_next )		/* { dg-error "operator|missing" } */
+#endif
+#if __has_include_next ("stdlib.h)
+#endif
+/* { dg-error "operator|missing\[^\n\r]*after" "" { target *-*-* } .-2 } */
+/* { dg-warning "missing terminating" "" { target *-*-* } .-3 } */
+#if __has_include_next (stdlib.h>)	/* { dg-error "operator|missing" } */
+#endif
+#if __has_include_next ("stdlib.h"	/* { dg-error "missing" } */
+#endif
+#if __has_include_next (		/* { dg-error "operator|missing" } */
+#endif
+#if __has_include_next			/* { dg-error "operator|missing" } */
+#endif
+#if __has_include_next"stdlib.h"	/* { dg-error "missing" } */
+#endif
+#if __has_include_next'h'		/* { dg-error "operator|missing" } */
+#endif
+#if __has_include_next('h'		/* { dg-error "operator|missing" } */
+#endif
+#if __has_include_next('h')		/* { dg-error "operator" } */
+#endif
+#define H(h) __has_include_next(h)
+#if H(<stdlib.h>)
+#else
+#error error 14
+#endif
+void
+foo ()
+{
+#pragma omp parallel if (__has_include_next ("<stdlib.h>"))
+  ;
+}