We make sure files end in \n by placing one at the limit of the buffer
(just past the end of what is read). We need to do the same for buffers
generated via include-translation. Fortunately they have space.
libcpp/
* files.c (_cpp_stack_file): Make buffers end in unread \n.
gcc/testsuite/
* g++.dg/modules/pr99050_a.H: New.
* g++.dg/modules/pr99050_b.C: New.
--
Nathan Sidwell
diff --git c/gcc/testsuite/g++.dg/modules/pr99050_a.H w/gcc/testsuite/g++.dg/modules/pr99050_a.H
new file mode 100644
index 00000000000..137e37f567f
--- /dev/null
+++ w/gcc/testsuite/g++.dg/modules/pr99050_a.H
@@ -0,0 +1,4 @@
+// PR c++/99050 ICE with directives only
+// { dg-additional-options -fmodule-header }
+// { dg-module-cmi {} }
+void f ();
diff --git c/gcc/testsuite/g++.dg/modules/pr99050_b.C w/gcc/testsuite/g++.dg/modules/pr99050_b.C
new file mode 100644
index 00000000000..439e216eb16
--- /dev/null
+++ w/gcc/testsuite/g++.dg/modules/pr99050_b.C
@@ -0,0 +1,7 @@
+// { dg-do preprocess }
+// { dg-additional-options {-fdirectives-only -fmodules-ts} }
+#include "pr99050_a.H"
+
+int main () {}
+
+// { dg-final { scan-file pr99050_b.i {import "[^\n]*99050_a.H" \[\[__translated\]\];\n} } }
diff --git c/libcpp/files.c w/libcpp/files.c
index 5ea3f8e1bf3..3a35f7c9743 100644
--- c/libcpp/files.c
+++ w/libcpp/files.c
@@ -918,13 +918,17 @@ _cpp_stack_file (cpp_reader *pfile, _cpp_file *file, include_type type,
because we don't usually need that location (we're popping an
include file). However in this case we do want to do the
increment. So push a writable buffer of two newlines to acheive
- that. */
- static uchar newlines[] = "\n\n";
+ that. (We also need an extra newline, so this looks like a regular
+ file, which we do that to to make sure we don't fall off the end in the
+ middle of a line. */
+ static uchar newlines[] = "\n\n\n";
cpp_push_buffer (pfile, newlines, 2, true);
+ size_t len = strlen (buf);
+ buf[len] = '\n'; /* See above */
cpp_buffer *buffer
= cpp_push_buffer (pfile, reinterpret_cast<unsigned char *> (buf),
- strlen (buf), true);
+ len, true);
buffer->to_free = buffer->buf;
file->header_unit = +1;
