commit 262275da43425ba2b8c240e47063e36b39167996

Author: Mark Wielaard <mark@klomp.org>

Date:   Wed Dec 12 13:55:01 2018 +0100

    Fix memcheck/tests/undef_malloc_args testcase.

diff --git a/coregrind/m_replacemalloc/vg_replace_malloc.c b/coregrind/m_replacemalloc/vg_replace_malloc.c

index 28bdb4a..564829a 100644

--- a/coregrind/m_replacemalloc/vg_replace_malloc.c

+++ b/coregrind/m_replacemalloc/vg_replace_malloc.c

@@ -216,9 +216,19 @@ static void init(void);

    Apart of allowing memcheck to detect an error, the macro

    TRIGGER_MEMCHECK_ERROR_IF_UNDEFINED has no effect and

    has a minimal cost for other tools replacing malloc functions.

+

+   Creating an "artificial" use of _x that works reliably is not entirely

+   straightforward.  Simply comparing it against zero often produces no

+   warning if _x contains at least one nonzero bit is defined, because

+   Memcheck knows that the result of the comparison will be defined (cf

+   expensiveCmpEQorNE).

+

+   Really we want to PCast _x, so as to create a value which is entirely

+   undefined if any bit of _x is undefined.  But there's no portable way to do

+   that.

 */

-#define TRIGGER_MEMCHECK_ERROR_IF_UNDEFINED(x) \

-   if ((ULong)x == 0) __asm__ __volatile__( "" ::: "memory" )

+#define TRIGGER_MEMCHECK_ERROR_IF_UNDEFINED(_x) \

+   if ((UWord)(_x) == 0) __asm__ __volatile__( "" ::: "memory" )

 /*---------------------- malloc ----------------------*/

@@ -504,7 +514,7 @@ static void init(void);

    void VG_REPLACE_FUNCTION_EZU(10040,soname,fnname) (void *zone, void *p)  \

    { \

       DO_INIT; \

-      TRIGGER_MEMCHECK_ERROR_IF_UNDEFINED((UWord) zone);	\

+      TRIGGER_MEMCHECK_ERROR_IF_UNDEFINED((UWord)zone ^ (UWord)p); \

       MALLOC_TRACE(#fnname "(%p, %p)\n", zone, p ); \

       if (p == NULL)  \

          return; \

diff --git a/memcheck/tests/undef_malloc_args.c b/memcheck/tests/undef_malloc_args.c

index 99e2799..654d70d 100644

--- a/memcheck/tests/undef_malloc_args.c

+++ b/memcheck/tests/undef_malloc_args.c

@@ -11,29 +11,29 @@ int main (int argc, char*argv[])

    {

       size_t size = def_size;

-      (void) VALGRIND_MAKE_MEM_UNDEFINED(&size, 1);

+      (void) VALGRIND_MAKE_MEM_UNDEFINED(&size, sizeof(size));

       p = malloc(size);

    }

-   (void) VALGRIND_MAKE_MEM_UNDEFINED(&p, 1);

+   (void) VALGRIND_MAKE_MEM_UNDEFINED(&p, sizeof(p));

    new_p = realloc(p, def_size);

-   (void) VALGRIND_MAKE_MEM_UNDEFINED(&new_p, 1);

+   (void) VALGRIND_MAKE_MEM_UNDEFINED(&new_p, sizeof(new_p));

    new_p = realloc(new_p, def_size);

-   (void) VALGRIND_MAKE_MEM_UNDEFINED(&new_p, 1);

+   (void) VALGRIND_MAKE_MEM_UNDEFINED(&new_p, sizeof(new_p));

    free (new_p);

    {

       size_t nmemb = 1;

-      (void) VALGRIND_MAKE_MEM_UNDEFINED(&nmemb, 1);

+      (void) VALGRIND_MAKE_MEM_UNDEFINED(&nmemb, sizeof(nmemb));

       new_p = calloc(nmemb, def_size);

       free (new_p);

    }

 #if 0

    {

       size_t alignment = 1;

-      (void) VALGRIND_MAKE_MEM_UNDEFINED(&alignment, 1);

+      (void) VALGRIND_MAKE_MEM_UNDEFINED(&alignment, sizeof(alignment));

       new_p = memalign(alignment, def_size);

       free(new_p);

    }

@@ -41,14 +41,14 @@ int main (int argc, char*argv[])

    {

       size_t nmemb = 16;

       size_t size = def_size;

-      (void) VALGRIND_MAKE_MEM_UNDEFINED(&size, 1);

+      (void) VALGRIND_MAKE_MEM_UNDEFINED(&size, sizeof(size));

       new_p = memalign(nmemb, size);

       free(new_p);

    }

    {

       size_t size = def_size;

-      (void) VALGRIND_MAKE_MEM_UNDEFINED(&size, 1);

+      (void) VALGRIND_MAKE_MEM_UNDEFINED(&size, sizeof(size));

       new_p = valloc(size);

       free (new_p);

    }