Fix a race condition diagnosed by gcc -Wsequence-point (Bug#8254).

An expression of the form (DOWNCASE (x) == DOWNCASE (y)), found in
dired.c's scmp function, had undefined behavior.
* lisp.h (DOWNCASE_TABLE, UPCASE_TABLE, DOWNCASE, UPPERCASEP):
(NOCASEP, LOWERCASEP, UPCASE, UPCASE1): Move from here ...
* buffer.h: ... to here, because these macros use current_buffer,
and the new implementation with inline functions needs to have
current_buffer in scope now, rather than later when the macros
are used.
(downcase, upcase1): New static inline functions.
(DOWNCASE, UPCASE1): Reimplement using these functions.
This avoids undefined behavior in expressions like
DOWNCASE (x) == DOWNCASE (y), which previously suffered
from race conditions in accessing the global variables
case_temp1 and case_temp2.
* casetab.c (case_temp1, case_temp2): Remove; no longer needed.
* lisp.h (case_temp1, case_temp2): Remove their decls.
* character.h (ASCII_CHAR_P): Move from here ...
* lisp.h: ... to here, so that the inline functions mentioned
above can use them.

1 files changed, 21 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 7468af4c725..7e873e3d85d 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,5 +1,26 @@
 2011-03-15  Paul Eggert  <eggert@cs.ucla.edu>
 
+        Fix a race condition diagnosed by gcc -Wsequence-point (Bug#8254).
+        An expression of the form (DOWNCASE (x) == DOWNCASE (y)), found in
+        dired.c's scmp function, had undefined behavior.
+        * lisp.h (DOWNCASE_TABLE, UPCASE_TABLE, DOWNCASE, UPPERCASEP):
+        (NOCASEP, LOWERCASEP, UPCASE, UPCASE1): Move from here ...
+        * buffer.h: ... to here, because these macros use current_buffer,
+        and the new implementation with inline functions needs to have
+        current_buffer in scope now, rather than later when the macros
+        are used.
+        (downcase, upcase1): New static inline functions.
+        (DOWNCASE, UPCASE1): Reimplement using these functions.
+        This avoids undefined behavior in expressions like
+        DOWNCASE (x) == DOWNCASE (y), which previously suffered
+        from race conditions in accessing the global variables
+        case_temp1 and case_temp2.
+        * casetab.c (case_temp1, case_temp2): Remove; no longer needed.
+        * lisp.h (case_temp1, case_temp2): Remove their decls.
+        * character.h (ASCII_CHAR_P): Move from here ...
+        * lisp.h: ... to here, so that the inline functions mentioned
+        above can use them.
+
         * dired.c (directory_files_internal_unwind): Now static.
 
         * fileio.c (file_name_as_directory, directory_file_name):