Hi!
In libcpp, lines are represented as linenum_type, which is unsigned int.
The following testcases ICE because maybe_print_line_1 is sometimes called
with UNKNOWN_LOCATION (e.g. at pragma eof) and while most of the time
the
&& src_line >= print.src_line
&& src_line < print.src_line + 8
check doesn't succeed for the src_line of 0 from UNKNOWN_LOCATION, when
print.src_line is from very large line numbers (UINT_MAX - 7 and above)
it succeeds (with UB on the compiler side) but src_file is NULL for
UNKNOWN_LOCATION and so the strcmp call ICEs.
As print.src_line can easily wrap around, this patch changes its type
to unsigned int to match libcpp, so that we don't invoke UB in the compiler.
For print.src_line of UINT_MAX - 7 and above, src_line from UNKNOWN_LOCATION
will not pass that test anymore, but when it wraps around to 0, it can,
so I've also added a check for src_loc != UNKNOWN_LOCATION (or, if
preferred, could be src_file != NULL).
Besides fixing the ICE and UB in the compiler, I believe worst case the
patch will cause printing a few more line directives in the preprocessed
source around the wrapping from lines UINT_MAX - 7 to 0 (but less
around the wrapping from INT_MAX to INT_MAX + 1U), but I think those
are exceptional cases (sources with > 2billion lines are rare and
we warn or error on #line > INT_MAX).
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2021-03-03 Jakub Jelinek <ja...@redhat.com>
PR c/99325
* c-ppoutput.c (print): Change src_line type from int to unsigned.
(token_streamer::stream) Likewise.
(maybe_print_line_1): Likewise. Don't strcmp src_file if src_loc is
UNKNOWN_LOCATION.
* gcc.dg/cpp/line11.c: New test.
* gcc.dg/cpp/line12.c: New test.
--- gcc/c-family/c-ppoutput.c.jj 2021-01-04 10:25:50.400102848 +0100
+++ gcc/c-family/c-ppoutput.c 2021-03-03 17:37:26.296185908 +0100
@@ -32,7 +32,7 @@ static struct
FILE *outf; /* Stream to write to. */
const cpp_token *prev; /* Previous token. */
const cpp_token *source; /* Source token for spacing. */
- int src_line; /* Line number currently being written.
*/
+ unsigned src_line; /* Line number currently being written. */
bool printed; /* True if something output at line. */
bool first_time; /* pp_file_change hasn't been called yet. */
bool prev_was_system_token; /* True if the previous token was a
@@ -213,7 +213,7 @@ token_streamer::stream (cpp_reader *pfil
/* Subtle logic to output a space if and only if necessary. */
if (avoid_paste)
{
- int src_line = LOCATION_LINE (loc);
+ unsigned src_line = LOCATION_LINE (loc);
if (print.source == NULL)
print.source = token;
@@ -237,7 +237,7 @@ token_streamer::stream (cpp_reader *pfil
}
else if (token->flags & PREV_WHITE)
{
- int src_line = LOCATION_LINE (loc);
+ unsigned src_line = LOCATION_LINE (loc);
if (src_line != print.src_line
&& do_line_adjustments
@@ -437,7 +437,7 @@ static bool
maybe_print_line_1 (location_t src_loc, FILE *stream)
{
bool emitted_line_marker = false;
- int src_line = LOCATION_LINE (src_loc);
+ unsigned src_line = LOCATION_LINE (src_loc);
const char *src_file = LOCATION_FILE (src_loc);
/* End the previous line of text. */
@@ -451,6 +451,7 @@ maybe_print_line_1 (location_t src_loc,
if (!flag_no_line_commands
&& src_line >= print.src_line
&& src_line < print.src_line + 8
+ && src_loc != UNKNOWN_LOCATION
&& strcmp (src_file, print.src_file) == 0)
{
while (src_line > print.src_line)
--- gcc/testsuite/gcc.dg/cpp/line11.c.jj 2021-03-03 17:45:22.353036566
+0100
+++ gcc/testsuite/gcc.dg/cpp/line11.c 2021-03-03 17:47:27.021670988 +0100
@@ -0,0 +1,6 @@
+/* PR c/99325 */
+/* { dg-do preprocess } */
+/* { dg-options "-pedantic" } */
+
+#line 4294967295 /* { dg-warning "line number out of range" } */
+#pragma message "foo"
--- gcc/testsuite/gcc.dg/cpp/line12.c.jj 2021-03-03 17:45:24.690011266
+0100
+++ gcc/testsuite/gcc.dg/cpp/line12.c 2021-03-03 17:47:33.121604153 +0100
@@ -0,0 +1,6 @@
+/* PR c/99325 */
+/* { dg-do preprocess } */
+/* { dg-options "-pedantic" } */
+
+#line 9223372036854775807 /* { dg-warning "line number out of range" } */
+#pragma message "foo"
Jakub
