From: "Xiao Zeng" <zengxiao@eswincomputing.com>
To: "Torbjorn SVENSSON" <torbjorn.svensson@foss.st.com>,
"newlib@sourceware.org" <newlib@sourceware.org>
Cc: "vapier@gentoo.org" <vapier@gentoo.org>,
"palmer@rivosinc.com" <palmer@rivosinc.com>,
jeffreyalaw <jeffreyalaw@gmail.com>
Subject: Re: Re: [PATCH] newlib: libc: Improved the readability of strcspn with minor optimization
Date: Sat, 16 Dec 2023 12:45:47 +0800 [thread overview]
Message-ID: <2023121612454699234314@eswincomputing.com> (raw)
In-Reply-To: <70b09ef7-fe4a-4669-ad27-2bd6c8bdca61@foss.st.com>
2023-12-15 18:28 Torbjorn SVENSSON <torbjorn.svensson@foss.st.com> wrote:
>
Hi Bob, I worked under the risc-v architecture and obtained the newlib library through
cross compilation. This is my first attempt to contribute code to newlib.
>Hello Xiao,
>
>On 2023-12-15 09:31, Xiao Zeng wrote:
>> Signed-off-by: Xiao Zeng <zengxiao@eswincomputing.com>
>> ---
>> newlib/libc/string/strcspn.c | 6 ++----
>> 1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/newlib/libc/string/strcspn.c b/newlib/libc/string/strcspn.c
>> index abaa93ad6..8ac0bf10c 100644
>> --- a/newlib/libc/string/strcspn.c
>> +++ b/newlib/libc/string/strcspn.c
>> @@ -37,12 +37,10 @@ strcspn (const char *s1,
>> for (c = s2; *c; c++)
>> {
>> if (*s1 == *c)
>> - break;
>> + goto end;
>> }
>> - if (*c)
>> - break;
>> s1++;
>> }
>> -
>> +end:
>> return s1 - s;
>> }
>
>Just looking at this small snippet of code, I would say that the
>previous code and your suggestion won't do the same thing.
>
>Do you have unit tests that confirm that the behavior is identical with
>the current implementation and your suggested change?
1 I must admit that I did not conduct a complete newlib regression test.
Anyway, I should apologize for this. After completing cross compilation, I tried:
-----------------
make check
-----------------
Received the following error message:
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Target is riscv64-unknown-elf
Host is x86_64-pc-linux-gnu
...
The error code is TCL LOOKUP COMMAND newlib_target_compile
The info on the error is:
invalid command name "newlib_target_compile"
while executing
"::tcl_unknown newlib_target_compile /home/user/Downloads/tools/tools.git/newlib.git/newlib/testsuite/newlib.iconv/iconvnm.c /home/user/Downloads/tools..."
("uplevel" body line 1)
invoked from within
"uplevel 1 ::tcl_unknown $args"
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
I know the reason for the error: Target and Host do not match, which
is a common issue in cross compilation. I have looked up some
information, but I have not found a solution.
2 On the basis of the above, I searched for test cases of the strcspn
function in newlib:
-------------------------------------------------------------------------------------------------
newlib/libm/test/string.c:311: check(strcspn("abcba", "qx") == 5); /* Whole string. */
newlib/libm/test/string.c:312: check(strcspn("abcba", "cx") == 2); /* Partial. */
newlib/libm/test/string.c:313: check(strcspn("abc", "abc") == 0); /* None. */
newlib/libm/test/string.c:314: check(strcspn("", "ab") == 0); /* Null string. */
newlib/libm/test/string.c:315: check(strcspn("abc", "") == 3); /* Null search list. */
-------------------------------------------------------------------------------------------------
I simply believe that these 5 test cases are all the test cases related to
strcspn in newlib. After local testing, all these test cases can pass in my patch.
>
>When I run your suggestion, I get return value 0, but with the current
>implementation it's 3 for this call: strspn("129th", "1234567890").
3 It is worth noting that strcspn and strspn only differ by one letter 'c'. I also
often confuse them -:), maybe you are the same.
>
>Kind regards,
>Torbjörn
4 Perhaps someone could point out how to test newlib under the risc-v
architecture, and I would greatly appreciate it. Of course, there are also
great methods for testing newlib under other architectures.
5 By the way, it is not possible to compile the latest newlib on host (x86_64-pc-linux-gnu)
(compilation quickly ended as if nothing had happened), even if ../configure
comes with the parameter -- with-newlib.
Thanks
Xiao Zeng
next prev parent reply other threads:[~2023-12-16 4:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-15 8:31 Xiao Zeng
2023-12-15 10:28 ` Torbjorn SVENSSON
2023-12-16 4:45 ` Xiao Zeng [this message]
2023-12-16 4:56 ` Xiao Zeng
2023-12-20 15:08 ` Torbjorn SVENSSON
2023-12-21 1:22 ` Xiao Zeng
2023-12-16 9:30 ` Xiao Zeng
2023-12-20 4:24 ` Jeff Johnston
2023-12-20 5:51 ` Xiao Zeng
2023-12-20 22:24 ` Brian Inglis
2023-12-21 8:00 ` Stefan Tauner
2023-12-21 17:47 ` Brian Inglis
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