Re: [PATCH] libcpp: Fix ICE on directive inside _Pragma() operator [PR67046]

[Jeff Law via Gcc-patches]

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

Ping: [PATCH] libcpp: Fix ICE on directive inside _Pragma() operator [PR67046]

[Lewis Hyatt via Gcc-patches]

Hello-

May I please ping this short patch that fixes an old bug? Thanks...

-Lewis

On Sat, Jan 14, 2023 at 1:46 PM Lewis Hyatt  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.
> ---
>
> 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
>
> diff --git a/gcc/testsuite/c-c++-common/cpp/pr67046.c 
> b/gcc/testsuite/c-c++-common/cpp/pr67046.c
> new file mode 100644
> index 000..f37f20c624e
> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/cpp/pr67046.c
> @@ -0,0 +1,10 @@
> +/* { dg-do preprocess } */
> +
> +_Pragma(
> +"message(\"msg\")"
> +)
> +
> +_Pragma(
> +"message(\"msg\")"
> +#
> +)
> diff --git a/libcpp/directives.cc b/libcpp/directives.cc
> index 9dc4363c65a..ffd262bce7d 100644
> --- a/libcpp/directives.cc
> +++ b/libcpp/directives.cc
> @@ -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)

[PATCH] libcpp: Fix ICE on directive inside _Pragma() operator [PR67046]

[Lewis Hyatt via Gcc-patches]

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

diff --git a/gcc/testsuite/c-c++-common/cpp/pr67046.c 
b/gcc/testsuite/c-c++-common/cpp/pr67046.c
new file mode 100644
index 000..f37f20c624e
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/cpp/pr67046.c
@@ -0,0 +1,10 @@
+/* { dg-do preprocess } */
+
+_Pragma(
+"message(\"msg\")"
+)
+
+_Pragma(
+"message(\"msg\")"
+#
+)
diff --git a/libcpp/directives.cc b/libcpp/directives.cc
index 9dc4363c65a..ffd262bce7d 100644
--- a/libcpp/directives.cc
+++ b/libcpp/directives.cc
@@ -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)