From: Bart Van Assche <bvanassche@acm.org>
Date: Fri, 4 Feb 2011 19:07:11 +0000 (+0000)
Subject: DRD: removed command-line option --free-is-write again since it is impossible
X-Git-Tag: svn/VALGRIND_3_7_0~682
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=fb1e012ed0928f901276318624cbfb9fd936547b;p=thirdparty%2Fvalgrind.git

DRD: removed command-line option --free-is-write again since it is impossible
to implement this functionality reliably.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@11522
---

diff --git a/NEWS b/NEWS
index 7c8331210a..2634fd48c6 100644
--- a/NEWS
+++ b/NEWS
@@ -5,6 +5,13 @@ Release 3.7.0 (???)
 
 
 
+Release 3.6.0 (... 2011)
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+DRD: removed command-line option --free-is-write again since it is impossible
+to implement this functionality reliably.
+
+
 Release 3.6.0 (21 October 2010)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 3.6.0 is a feature release with many significant improvements and the
diff --git a/drd/docs/drd-manual.xml b/drd/docs/drd-manual.xml
index 6d70b26823..21adaa2125 100644
--- a/drd/docs/drd-manual.xml
+++ b/drd/docs/drd-manual.xml
@@ -361,20 +361,6 @@ behavior of the DRD tool itself:</para>
       </para>
     </listitem>
   </varlistentry>
-  <varlistentry>
-    <term>
-      <option>
-        <![CDATA[--free-is-write=<yes|no> [default: no]]]>
-      </option>
-    </term>
-    <listitem>
-      <para>
-        Whether to report accessing freed memory as a race. Helps to detect
-        memory accesses that occur after memory has been freed but might cause
-        DRD to run slightly slower.
-      </para>
-    </listitem>
-  </varlistentry>
   <varlistentry>
     <term>
       <option>
diff --git a/drd/drd_main.c b/drd/drd_main.c
index ebf08459ba..239f4988c1 100644
--- a/drd/drd_main.c
+++ b/drd/drd_main.c
@@ -55,7 +55,6 @@
 
 /* Local variables. */
 
-static Bool s_free_is_write    = False;
 static Bool s_print_stats      = False;
 static Bool s_var_info         = False;
 static Bool s_show_stack_usage = False;
@@ -92,7 +91,6 @@ static Bool DRD_(process_cmd_line_option)(Char* arg)
    if      VG_BOOL_CLO(arg, "--check-stack-var",     check_stack_accesses) {}
    else if VG_BOOL_CLO(arg, "--drd-stats",           s_print_stats) {}
    else if VG_BOOL_CLO(arg, "--first-race-only",     first_race_only) {}
-   else if VG_BOOL_CLO(arg, "--free-is-write",       s_free_is_write) {}
    else if VG_BOOL_CLO(arg,"--report-signal-unlocked",report_signal_unlocked)
    {}
    else if VG_BOOL_CLO(arg, "--segment-merging",     segment_merging) {}
@@ -188,8 +186,6 @@ static void DRD_(print_usage)(void)
 "                              time (in milliseconds) [off].\n"
 "    --first-race-only=yes|no  Only report the first data race that occurs on\n"
 "                              a memory location instead of all races [no].\n"
-"    --free-is-write=yes|no    Whether to report races between freeing memory\n"
-"                              and subsequent accesses of that memory[no].\n"
 "    --report-signal-unlocked=yes|no Whether to report calls to\n"
 "                              pthread_cond_signal() where the mutex associated\n"
 "                              with the signal via pthread_cond_wait() is not\n"
@@ -339,12 +335,10 @@ void drd_stop_using_mem(const Addr a1, const SizeT len,
 
    if (!is_stack_mem || DRD_(get_check_stack_accesses)())
    {
-      DRD_(thread_stop_using_mem)(a1, a2, !is_stack_mem && s_free_is_write);
+      DRD_(thread_stop_using_mem)(a1, a2, False);
       DRD_(clientobj_stop_using_mem)(a1, a2);
       DRD_(suppression_stop_using_mem)(a1, a2);
    }
-   if (!is_stack_mem && s_free_is_write)
-      DRD_(trace_store)(a1, len);
 }
 
 static __inline__
diff --git a/drd/tests/Makefile.am b/drd/tests/Makefile.am
index 818c2b3e7a..ea2813209a 100644
--- a/drd/tests/Makefile.am
+++ b/drd/tests/Makefile.am
@@ -170,8 +170,6 @@ EXTRA_DIST =                                        \
 	qt4_rwlock.vgtest                           \
 	qt4_semaphore.stderr.exp                    \
 	qt4_semaphore.vgtest                        \
-	read_after_free.stderr.exp		    \
-	read_after_free.vgtest			    \
 	recursive_mutex.stderr.exp-linux            \
 	recursive_mutex.stderr.exp-darwin           \
 	recursive_mutex.vgtest                      \
@@ -311,7 +309,6 @@ check_PROGRAMS +=        \
   annotate_smart_pointer \
   atomic_var             \
   circular_buffer        \
-  read_after_free        \
   tsan_unittest
 endif
 
diff --git a/drd/tests/read_after_free.c b/drd/tests/read_after_free.c
deleted file mode 100644
index 1319cb2a2b..0000000000
--- a/drd/tests/read_after_free.c
+++ /dev/null
@@ -1,45 +0,0 @@
-#define _GNU_SOURCE 1
-
-#include <assert.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <pthread.h>
-
-static char* s_mem;
-static volatile int s_freed;
-
-static void* thread_func(void* arg)
-{
-    // Busy-wait until pthread_create() has finished.
-    while (s_freed == 0)
-        pthread_yield();
-    free(s_mem);
-    __sync_add_and_fetch(&s_freed, 1);
-    return NULL;
-}
-
-int main(int argc, char** argv)
-{
-    pthread_t tid;
-    int quiet;
-    char result;
-
-    quiet = argc > 1;
-
-    s_mem = malloc(10);
-    if (!quiet)
-        fprintf(stderr, "Pointer to allocated memory: %p\n", s_mem);
-    assert(s_mem);
-    pthread_create(&tid, NULL, thread_func, NULL);
-    __sync_add_and_fetch(&s_freed, 1);
-    // Busy-wait until the memory has been freed.
-    while (s_freed == 1)
-        pthread_yield();
-    // Read-after-free.
-    result = s_mem[0];
-    if (!quiet)
-        fprintf(stderr, "Read-after-free result: %d\n", result);
-    pthread_join(tid, NULL);
-    fprintf(stderr, "Done.\n");
-    return 0;
-}
diff --git a/drd/tests/read_after_free.stderr.exp b/drd/tests/read_after_free.stderr.exp
deleted file mode 100644
index 7463c72104..0000000000
--- a/drd/tests/read_after_free.stderr.exp
+++ /dev/null
@@ -1,8 +0,0 @@
-
-Conflicting load by thread 1 at 0x........ size 1
-   at 0x........: main (read_after_free.c:?)
-Allocation context: unknown.
-
-Done.
-
-ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)
diff --git a/drd/tests/read_after_free.vgtest b/drd/tests/read_after_free.vgtest
deleted file mode 100644
index c8b1c2bdea..0000000000
--- a/drd/tests/read_after_free.vgtest
+++ /dev/null
@@ -1,4 +0,0 @@
-prereq: test -e read_after_free && ./supported_libpthread
-vgopts: --read-var-info=yes --check-stack-var=yes --free-is-write=yes --show-confl-seg=no
-prog: read_after_free
-args: -q