On Tue, May 30, 2017 at 07:17:27AM +0900, Akira Yokosawa wrote:
> >From e325a5ff132d8e4a79dfe465b18f573b97da75db Mon Sep 17 00:00:00 2001
> From: Akira Yokosawa <akiyks@xxxxxxxxx>
> Date: Sun, 28 May 2017 12:38:27 +0900
> Subject: [RFC PATCH 3/4] CodeSamples: Use 'intptr_t' to be compatible with 'void *'
>
> On x86_64, casting between "int" and "void *" in threadcreate.c
> causes GCC to emit warnings such as:
>
> warning: cast from pointer to integer of different size
> warning: cast from integer to pointer of different size
>
> Let's adopt C99 way of writing portable code.
>
> Also do the same changes where appropriate. (Other than
> threadcreate.c, no warnings were observed on x86_64, but we can
> remove a few casts to "long".)
>
> Signed-off-by: Akira Yokosawa <akiyks@xxxxxxxxx>
> ---
> CodeSamples/SMPdesign/matmul.c | 13 +++++++------
> CodeSamples/SMPdesign/smpalloc.c | 11 ++++++-----
> CodeSamples/defer/gettimestampmp.c | 2 +-
> CodeSamples/intro/threadcreate.c | 7 ++++---
> 4 files changed, 18 insertions(+), 15 deletions(-)
>
> diff --git a/CodeSamples/SMPdesign/matmul.c b/CodeSamples/SMPdesign/matmul.c
> index 6a07730..9f0b250 100644
> --- a/CodeSamples/SMPdesign/matmul.c
> +++ b/CodeSamples/SMPdesign/matmul.c
> @@ -18,12 +18,13 @@
> * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
> */
>
> +#include <inttypes.h>
> #include "../api.h"
>
> float *a;
> float *b;
> float *c;
> -long dim = 1000;
> +intptr_t dim = 1000;
This really is an int, used only for array index calculations. I don't
see how it helps to make it be an intptr_t. What am I missing?
> int nthread = 1;
>
> #define GOFLAG_INIT 0
> @@ -38,8 +39,8 @@ atomic_t nstarted;
>
> void *matmul_thread(void *me_in)
> {
> - long me = (long)me_in;
> - int i, j, k;
> + intptr_t me = (intptr_t)me_in;
> + intptr_t i, j, k;
Hmmm... Now "me" is a long and used as such, but the conversion from
a pointer on 32-bit systems could get warnings on some systems. But
it is guaranteed to be a small integer. Would something like this work?
int me = (int)(long)me_in;
Or this?
int me = (intptr_t)me_in;
Or even this?
int me = ((intptr_t)me_in) & 0xffffffff;
I suppose that the painfully correct way to do this would be to pass in
a pointer to a structure containing a lone int. Any other approaches
that work?
The variables i, j, and k, like dim, are used only as int to compute
array indexes.
I have similar concerns about the remaining cases. I am not inalterably
opposed, but it seems better to keep intptr_t usage more confined.
Thanx, Paul
> atomic_inc(&nstarted);
> while (goflag == GOFLAG_INIT)
> @@ -58,7 +59,7 @@ void *matmul_thread(void *me_in)
>
> int main(int argc, char *argv[])
> {
> - int i, j;
> + intptr_t i, j;
> long long startcreatetime;
> long long starttime;
> long long endtime;
> @@ -87,7 +88,7 @@ int main(int argc, char *argv[])
> goflag = GOFLAG_INIT;
> startcreatetime = get_microseconds();
> for (i = 0; i < nthread; i++)
> - create_thread(matmul_thread, (void *)(long)i);
> + create_thread(matmul_thread, (void *)i);
> while (atomic_read(&nstarted) != nthread)
> barrier();
> starttime = get_microseconds();
> @@ -95,7 +96,7 @@ int main(int argc, char *argv[])
> while (atomic_read(&ndone) != nthread)
> poll(NULL, 0, 1);
> endtime = get_microseconds();
> - printf("dim = %ld, nthread = %d, duration = %lld : %lld us\n",
> + printf("dim = %" PRIdPTR ", nthread = %d, duration = %lld : %lld us\n",
> dim, nthread, endtime - startcreatetime, endtime - starttime);
> return 0;
> }
> diff --git a/CodeSamples/SMPdesign/smpalloc.c b/CodeSamples/SMPdesign/smpalloc.c
> index 95b21a1..0882f63 100644
> --- a/CodeSamples/SMPdesign/smpalloc.c
> +++ b/CodeSamples/SMPdesign/smpalloc.c
> @@ -19,6 +19,7 @@
> * Copyright (c) 2006 Paul E. McKenney, IBM Corporation.
> */
>
> +#include <inttypes.h>
> #include "../api.h"
>
> #define TARGET_POOL_SIZE 3
> @@ -123,7 +124,7 @@ void *memblock_test(void *arg)
> long cnt = 0;
> long cntfail = 0;
> int i;
> - int runlength = (int)(long)arg;
> + intptr_t runlength = (intptr_t)arg;
> struct memblock *p[MAX_RUN];
>
> if (runlength > MAX_RUN)
> @@ -159,7 +160,7 @@ int main(int argc, char *argv[])
> long long nc;
> long long nf;
> int nkids = 1;
> - int runlength = 1;
> + intptr_t runlength = 1;
> int totbefore;
>
> smp_init();
> @@ -176,12 +177,12 @@ int main(int argc, char *argv[])
> if (argc > 2) {
> runlength = strtoul(argv[2], NULL, 0);
> if (runlength > MAX_RUN) {
> - fprintf(stderr, "nkids = %d too large, max = %d\n",
> + fprintf(stderr, "nkids = %" PRIdPTR " too large, max = %d\n",
> runlength, MAX_RUN);
> usage(argv[0]);
> }
> }
> - printf("%d %d ", nkids, runlength);
> + printf("%d %" PRIdPTR, nkids, runlength);
>
> init_per_thread(results, 0L);
> init_per_thread(failures, 0L);
> @@ -189,7 +190,7 @@ int main(int argc, char *argv[])
>
> goflag = 1;
> for (i = 0; i < nkids; i++)
> - create_thread(memblock_test, (void *)(long)runlength);
> + create_thread(memblock_test, (void *)runlength);
>
> sleep(1);
> goflag = 0;
> diff --git a/CodeSamples/defer/gettimestampmp.c b/CodeSamples/defer/gettimestampmp.c
> index bc0b9ea..e794e82 100644
> --- a/CodeSamples/defer/gettimestampmp.c
> +++ b/CodeSamples/defer/gettimestampmp.c
> @@ -29,7 +29,7 @@ long curtimestamp = 0;
>
> void *collect_timestamps(void *mask_in)
> {
> - long mask = (long)mask_in;
> + intptr_t mask = (intptr_t)mask_in;
>
> while (curtimestamp < MAX_TIMESTAMPS) {
> while ((curtimestamp & CURTIMESTAMP_MASK) != mask)
> diff --git a/CodeSamples/intro/threadcreate.c b/CodeSamples/intro/threadcreate.c
> index 26b7ba9..470bb11 100644
> --- a/CodeSamples/intro/threadcreate.c
> +++ b/CodeSamples/intro/threadcreate.c
> @@ -18,13 +18,14 @@
> * Copyright (c) 2006 Paul E. McKenney, IBM Corporation.
> */
>
> +#include <inttypes.h>
> #include "../api.h"
>
> void *thread_test(void *arg)
> {
> - int myarg = (int)arg;
> + intptr_t myarg = (intptr_t)arg;
>
> - printf("child thread %d: smp_thread_id() = %d\n",
> + printf("child thread %" PRIdPTR ": smp_thread_id() = %d\n",
> myarg, smp_thread_id());
> return NULL;
> }
> @@ -38,7 +39,7 @@ void usage(char *progname)
>
> int main(int argc, char *argv[])
> {
> - int i;
> + intptr_t i;
> int nkids = 1;
>
> smp_init();
> --
> 2.7.4
>
>
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