c-ppoutput: Fix preprocessing ICE on very large line number [PR99325]
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). 2021-03-04 Jakub Jelinek <jakub@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.
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@ -32,7 +32,7 @@ static struct
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FILE *outf; /* Stream to write to. */
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const cpp_token *prev; /* Previous token. */
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const cpp_token *source; /* Source token for spacing. */
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int src_line; /* Line number currently being written. */
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unsigned src_line; /* Line number currently being written. */
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bool printed; /* True if something output at line. */
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bool first_time; /* pp_file_change hasn't been called yet. */
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bool prev_was_system_token; /* True if the previous token was a
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@ -213,7 +213,7 @@ token_streamer::stream (cpp_reader *pfile, const cpp_token *token,
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/* Subtle logic to output a space if and only if necessary. */
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if (avoid_paste)
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{
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int src_line = LOCATION_LINE (loc);
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unsigned src_line = LOCATION_LINE (loc);
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if (print.source == NULL)
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print.source = token;
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@ -237,7 +237,7 @@ token_streamer::stream (cpp_reader *pfile, const cpp_token *token,
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}
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else if (token->flags & PREV_WHITE)
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{
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int src_line = LOCATION_LINE (loc);
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unsigned src_line = LOCATION_LINE (loc);
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if (src_line != print.src_line
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&& do_line_adjustments
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@ -437,7 +437,7 @@ static bool
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maybe_print_line_1 (location_t src_loc, FILE *stream)
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{
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bool emitted_line_marker = false;
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int src_line = LOCATION_LINE (src_loc);
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unsigned src_line = LOCATION_LINE (src_loc);
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const char *src_file = LOCATION_FILE (src_loc);
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/* End the previous line of text. */
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@ -451,6 +451,7 @@ maybe_print_line_1 (location_t src_loc, FILE *stream)
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if (!flag_no_line_commands
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&& src_line >= print.src_line
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&& src_line < print.src_line + 8
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&& src_loc != UNKNOWN_LOCATION
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&& strcmp (src_file, print.src_file) == 0)
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{
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while (src_line > print.src_line)
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@ -0,0 +1,6 @@
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/* PR c/99325 */
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/* { dg-do preprocess } */
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/* { dg-options "-pedantic" } */
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#line 4294967295 /* { dg-warning "line number out of range" } */
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#pragma message "foo"
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@ -0,0 +1,6 @@
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/* PR c/99325 */
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/* { dg-do preprocess } */
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/* { dg-options "-pedantic" } */
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#line 9223372036854775807 /* { dg-warning "line number out of range" } */
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#pragma message "foo"
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