PR preprocessor/78680 identifies a crash when attempting to issue
a -Wformat warning, where the format string includes a string token
split across multiple physical source lines via backslash-continued
lines.
The issue is that libcpp is generating bogus range information for
such tokens.
For example, in:
void fn1() {
__builtin_printf("\
%ld.\n\
2\n"); };
the range of the string token is printed as:
__builtin_printf("\
^~
whereas the range ought to be:
__builtin_printf("\
^~
%ld.\n\
~~~~~~~
2\n"); };
~~~~
The root cause is that the line notes expressing the update
of the buffer in lex.c aren't yet updated when the end-point of
the token is computed
3095 tok_range.m_finish
3096 = linemap_position_for_column (pfile->line_table,
3097 CPP_BUF_COLUMN (buffer,
buffer->cur));
so that the physical line is still regarded as that of the start
of the token, and, where CPP_BUF_COLUMN uses (BUF)->line_base,
line_base is still the location of the first physical line in the
and hence the column information is too large (as if it were the
offset in the *logical* line).
(the printed range is somewhat misleading; the actual buggy range
extends beyond the "\ in the line, but within diagnostic-show-locus.c
layout::print_annotation_line only prints up to the xbound set by
layout::print_source_line and so truncates most of the buggy range).
The fix is to ensure that line notes are handled before calculating
the end-point of the token range.
This leads to the range for the string token being correctly
computed, as:
__builtin_printf("\
^~
%ld.\n\
~~~~~~~
2\n"); };
~~~~
and this leads to get_substring_ranges_for_loc failing gracefully,
rather than crashing.
Successfully bootstrapped®rtested on x86_64-pc-linux-gnu; adds
10 PASS results to gcc.sum.
Committed to trunk as r243567.
gcc/testsuite/ChangeLog:
PR preprocessor/78680
* gcc.dg/format/pr78680.c: New test case.
* gcc.dg/plugin/diagnostic-test-expressions-1.c
(test_multiline_token): New function.
* gcc.dg/plugin/diagnostic-test-string-literals-1.c
(test_backslash_continued_logical_lines): New function.
libcpp/ChangeLog:
PR preprocessor/78680
* lex.c (_cpp_lex_direct): Ensure line notes are processed before
computing the end-point of the token.
---
gcc/testsuite/gcc.dg/format/pr78680.c | 16 ++++++++++++++++
.../gcc.dg/plugin/diagnostic-test-expressions-1.c | 19 +++++++++++++++++++
.../plugin/diagnostic-test-string-literals-1.c | 20 ++++++++++++++++++++
libcpp/lex.c | 7 +++++++
4 files changed, 62 insertions(+)
create mode 100644 gcc/testsuite/gcc.dg/format/pr78680.c
diff --git a/gcc/testsuite/gcc.dg/format/pr78680.c
b/gcc/testsuite/gcc.dg/format/pr78680.c
new file mode 100644
index 0000000..0c599f3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/format/pr78680.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -Wall -Wextra -fdiagnostics-show-caret" } */
+
+void fn1() {
+ __builtin_printf("\
+ %ld.\n\
+ 2\n"); };
+/* { dg-warning "expects a matching" "" { target *-*-* } .-3 } */
+/* { dg-begin-multiline-output "" }
+ __builtin_printf("\
+ ^~
+ %ld.\n\
+ ~~~~~~~
+ 2\n"); };
+ ~~~~
+ { dg-end-multiline-output "" } */
diff --git a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c
b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c
index 9372936..afbe0f7 100644
--- a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c
+++ b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-expressions-1.c
@@ -689,3 +689,22 @@ void test_multiple_ordinary_maps (void)
~~
{ dg-end-multiline-output "" } */
}
+
+/* Verify that we correctly handle a token that spans multiple
+ physical lines. */
+
+const char *test_multiline_token (void)
+{
+ __emit_expression_range (0, "foo\
+bar\
+baz");
+/* { dg-warning "range" "" { target *-*-* } .-3 } */
+/* { dg-begin-multiline-output "" }
+ __emit_expression_range (0, "foo\
+ ^~~~~
+ bar\
+ ~~~~
+ baz");
+ ~~~~
+ { dg-end-multiline-output "" } */
+}
diff --git a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-literals-1.c
b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-literals-1.c
index 76a085e..03f042a 100644
--- a/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-literals-1.c
+++ b/gcc/testsuite/gcc.dg/plugin/diagnostic-test-string-literals-1.c
@@ -272,3 +272,23 @@ test_terminator_location (void)
^
{ dg-end-multiline-output "" } */
}
+
+/* Verify that we fail gracefully when a string literal token is split
+ across multiple physical lines. */
+
+void
+test_backslash_continued_logical_lines (void)
+{
+ __emit_string_literal_range ("\
+01234\
+56789", 6, 6, 7);
+ /* { dg-error "unable to read substring location: range endpoints are on
different lines" "" { target *-*-* } .-3 } */
+ /* { dg-begin-multiline-output "" }
+ __emit_string_literal_range ("\
+ ^~
+ 01234\
+ ~~~~~~
+ 56789", 6, 6, 7);
+ ~~~~~~
+ { dg-end-multiline-output "" } */
+}
diff --git a/libcpp/lex.c b/libcpp/lex.c
index cea8848..ae45892 100644
--- a/libcpp/lex.c
+++ b/libcpp/lex.c
@@ -3089,6 +3089,13 @@ _cpp_lex_direct (cpp_reader *pfile)
break;
}
+ /* Ensure that any line notes are processed, so that we have the
+ correct physical line/column for the end-point of the token even
+ when a logical line is split via one or more backslashes. */
+ if (buffer->cur >= buffer->notes[buffer->cur_note].pos
+ && !pfile->overlaid_buffer)
+ _cpp_process_line_notes (pfile, false);
+
source_range tok_range;
tok_range.m_start = result->src_loc;
if (result->src_loc >= RESERVED_LOCATION_COUNT)
--
1.8.5.3
