libcpp: Fix ICE on directive inside _Pragma() operator [PR67046]
Commit Message
get__Pragma_string() in directives.cc is responsible for lexing the parens
and the string argument from a _Pragma("...") operator. This function does
not handle the case when the closing paren is not on the same line as the
string; in that case, libcpp will by default reuse the token buffer it
previously used for the string, so that the string token returned by
get__Pragma_string() may be corrupted, as shown in the testcase. Fix using
the existing keep_tokens mechanism that temporarily disables the reuse of
token buffers.
libcpp/ChangeLog:
PR preprocessor/67046
* directives.cc (_cpp_do__Pragma): Increment pfile->keep_tokens to
ensure the returned string token is valid.
gcc/testsuite/ChangeLog:
PR preprocessor/67046
* c-c++-common/cpp/pr67046.c: New test.
---
Notes:
Hello-
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67046
This fixes an old ICE in libcpp that can happen when lexing the tokens from a
_Pragma operator. Bootstrapped+tested on x86-64 Linux with no
regressions. Please let me know if it's OK? Thanks...
-Lewis
gcc/testsuite/c-c++-common/cpp/pr67046.c | 10 ++++++++++
libcpp/directives.cc | 5 +++++
2 files changed, 15 insertions(+)
create mode 100644 gcc/testsuite/c-c++-common/cpp/pr67046.c
Comments
On 1/14/23 11:46, Lewis Hyatt via Gcc-patches wrote:
> get__Pragma_string() in directives.cc is responsible for lexing the parens
> and the string argument from a _Pragma("...") operator. This function does
> not handle the case when the closing paren is not on the same line as the
> string; in that case, libcpp will by default reuse the token buffer it
> previously used for the string, so that the string token returned by
> get__Pragma_string() may be corrupted, as shown in the testcase. Fix using
> the existing keep_tokens mechanism that temporarily disables the reuse of
> token buffers.
>
> libcpp/ChangeLog:
>
> PR preprocessor/67046
> * directives.cc (_cpp_do__Pragma): Increment pfile->keep_tokens to
> ensure the returned string token is valid.
>
> gcc/testsuite/ChangeLog:
>
> PR preprocessor/67046
> * c-c++-common/cpp/pr67046.c: New test.
OK for the trunk.
Sorry for the long wait.
jeff
new file mode 100644
@@ -0,0 +1,10 @@
+/* { dg-do preprocess } */
+
+_Pragma(
+"message(\"msg\")"
+)
+
+_Pragma(
+"message(\"msg\")"
+#
+)
@@ -1996,7 +1996,12 @@ destringize_and_run (cpp_reader *pfile, const cpp_string *in,
int
_cpp_do__Pragma (cpp_reader *pfile, location_t expansion_loc)
{
+ /* Make sure we don't invalidate the string token, if the closing parenthesis
+ ended up on a different line. */
+ ++pfile->keep_tokens;
const cpp_token *string = get__Pragma_string (pfile);
+ --pfile->keep_tokens;
+
pfile->directive_result.type = CPP_PADDING;
if (string)