libcpp: Fix macro expansion for argument of __has_include [PR110558]

When the file name for a #include directive is the result of stringifying a
macro argument, libcpp needs to take some care to get the whitespace
correct; in particular stringify_arg() needs to see a CPP_PADDING token
between macro tokens so that it can figure out when to output space between
tokens. The CPP_PADDING tokens are not normally generated when handling a
preprocessor directive, but for #include-like directives, libcpp sets the
state variable pfile->state.directive_wants_padding to TRUE so that the
CPP_PADDING tokens will be output, and then everything works fine for
computed includes.

As the PR points out, things do not work fine for __has_include. Fix that by
setting the state variable the same as is done for #include.

libcpp/ChangeLog:

	PR preprocessor/110558
	* macro.cc (builtin_has_include): Set
	pfile->state.directive_wants_padding prior to lexing the
	file name, in case it comes from macro expansion.

gcc/testsuite/ChangeLog:

	PR preprocessor/110558
	* c-c++-common/cpp/has-include-2.c: New test.
	* c-c++-common/cpp/has-include-2.h: New test.

diff --git a/gcc/testsuite/c-c++-common/cpp/has-include-2.c b/gcc/testsuite/c-c++-common/cpp/has-include-2.c
new file mode 100644 (file)
index 0000000..5cd00cb
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/cpp/has-include-2.c
@@ -0,0 +1,12 @@
+/* PR preprocessor/110558 */
+/* { dg-do preprocess } */
+#define STRINGIZE(x) #x
+#define GET_INCLUDE(i) STRINGIZE(has-include-i.h)
+/* Spaces surrounding the macro args previously caused a problem for __has_include().  */
+#if __has_include(GET_INCLUDE(2)) && __has_include(GET_INCLUDE( 2)) && __has_include(GET_INCLUDE( 2 ))
+#include GET_INCLUDE(2)
+#include GET_INCLUDE( 2)
+#include GET_INCLUDE( 2 )
+#else
+#error "__has_include did not handle padding properly" /* { dg-bogus "__has_include" } */
+#endif

diff --git a/gcc/testsuite/c-c++-common/cpp/has-include-2.h b/gcc/testsuite/c-c++-common/cpp/has-include-2.h
new file mode 100644 (file)
index 0000000..57c402b
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/cpp/has-include-2.h
@@ -0,0 +1 @@
+/* PR preprocessor/110558 */

diff --git a/libcpp/macro.cc b/libcpp/macro.cc
index a3d2c159f8cb962d3e354087cdbfbbe2c3b34c7a..352eb2e4fd99fa1a5d373ad68bccfda258eeaca2 100644 (file)
--- a/libcpp/macro.cc
+++ b/libcpp/macro.cc
@@ -398,6 +398,8 @@ builtin_has_include (cpp_reader *pfile, cpp_hashnode *op, bool has_next)
               NODE_NAME (op));
 
   pfile->state.angled_headers = true;
+  const auto sav_padding = pfile->state.directive_wants_padding;
+  pfile->state.directive_wants_padding = true;
   const cpp_token *token = cpp_get_token_no_padding (pfile);
   bool paren = token->type == CPP_OPEN_PAREN;
   if (paren)
@@ -406,6 +408,7 @@ builtin_has_include (cpp_reader *pfile, cpp_hashnode *op, bool has_next)
     cpp_error (pfile, CPP_DL_ERROR,
               "missing '(' before \"%s\" operand", NODE_NAME (op));
   pfile->state.angled_headers = false;
+  pfile->state.directive_wants_padding = sav_padding;
 
   bool bracket = token->type != CPP_STRING;
   char *fname = NULL;