<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style></style></head><body lang=ZH-CN link=blue vlink=purple style='text-justify-trim:punctuation'><div class=WordSection1><o:p> </o:p><o:p> </o:p>>-----Original Message----->From: YunQiang Su [mailto:wzssyqa@gmail.com]>Sent: Thursday, February 27, 2020 11:38 AM>To: Shiyou Yin>Cc: pixman@lists.freedesktop.org>Subject: Re: [Pixman] [PATCH v2 2/3] build: use '-mloongson-mmi' for Loongson MMI.><o:p> </o:p>>在 2020-02-26三的 17:45 +0800，Shiyou Yin写道：>> > -----Original Message----->> > From: YunQiang Su [mailto:wzssyqa@gmail.com]>> > Sent: Saturday, February 22, 2020 10:20 PM>> > To: Shiyou Yin>> > Cc: pixman@lists.freedesktop.org>> > Subject: Re: [Pixman] [PATCH v2 2/3] build: use '-mloongson-mmi'>> > for Loongson MMI.>> >>> > Shiyou Yin <yinshiyou-hf@loongson.cn> 于2020年2月22日周六 下午9:19写道：>> > > First let's clarify what exactly compatibility mean, or what>> > > specific goals we want to achieve.>> > >>> > > If it's just ensure the features of new code consistent with old>> > > compilation and hardware environment, then this patch will works>> > > well.>> > >>> >>> > Of course that is not enough. If it is the only your goal, why sent>> > this patch?>> >>> > > If it is going to make sure MMI can be enabled and works well on>> > > each cases, it may be not easy.>> > >>> > > Guess compiler? Compiler check can only ensure the compile option>> > > is supported or not>> >>> > yq@ls3b1500:~$ gcc -march=loongson3a -dM -E - < /dev/null | grep mmi>> > #define __mips_loongson_mmi 1>> >>> > So, you can try to compile (-c) the bellow code to test whether the>> > compiler has MMI enabled>> >>> > #ifndef __mips_loongson_mmi>> > # error "Loongson MMI is not supported">> > #endif>> >>> > For example, mipsel-linux-gnu-gcc is a generic mips compiler and>> > target mips32r2; and the user set CC="mipsel-linux-gnu-gcc>> > -march=loongson3", Your test can still pass.>> >>> >>> > > and then MMI instruction can be compiled. We can't ensure the>> > > binary can works well on each hardware, especially in the case of>> > > cross-compilation.>> >>> > Sure, that why you need to obey users configure, by LS_CFLAGS or CC>> > or the default configure of compiler.>> >>> > > Almost all latest gcc support "-march=loongson2f" and "->> > > march=loongson3a">> > > and "-mloongson-mmi". So which kind of compiler we will set>> > > LS_CFLAGS as -mloongson-mmi?>> >>> > due to history reason, the default value of LS_CFLAGS should be keep>> > as 2f, and user can set it by>> >>> > LS_CFLAGS="-mloongson-mmi" ./configure -- blabla>> >>> > > Guess CPU is always used in runtime check, it should be added in>> > > the optimization code but not in configure. The configure just>> > > need to ensure the compile process can finished successfully, So>> > > it may check compiler support some options or not and then>> > > enable/disable the features.>> > >>> >>> > Generally, we don't need to guess the BUILD_MACHINE's cpu in>> > buildtime.>> >>><o:p> </o:p>>> If this is what you mean, I will agree and update the patch.>> It should be noted that we still need to manually specify appropriate>> option to enable MMI correctly.>> The only change is now we have two new ways(2 & 3) to specify this>> option:>> 1) LS_CFLAGS>> 2) CC>> 3)compiler's default cflags, such as COLLECT_GCC_OPTIONS of gcc.>><o:p> </o:p>>><o:p> </o:p>>> Diff is as follows:>><o:p> </o:p>>> diff --git a/configure.ac b/configure.ac index 1ca3974..be9212d 100644>> --- a/configure.ac>> +++ b/configure.ac>> @@ -78,7 +78,7 @@ AC_C_BIGENDIAN>> AC_C_INLINE>><o:p> </o:p>>> dnl PIXMAN_LINK_WITH_ENV(env-setup, program, true-action, false->> action)>> -dnl>> +>> dnl Compiles and links the given program in the environment setup by>> env-setup dnl and executes true-action on success and false-action on>> failure.>> AC_DEFUN([PIXMAN_LINK_WITH_ENV],[dnl>> @@ -273,7 +273,27 @@ dnl>> =====================================================================>> ======>> dnl Check for Loongson Multimedia Instructions>><o:p> </o:p>>> if test "x$LS_CFLAGS" = "x" ; then>> - LS_CFLAGS="-march=loongson2f">> + # check default cflags to set LS_CFLAGS # Has -mloongson-mmi or>> + -march=loongson3a : LS_CFLAGS="-mloongson->> mmi">> + # else : LS_CFLAGS="-march=loongson2f">> + xserver_save_CFLAGS=$CFLAGS>> + CFLAGS=" $LS_CFLAGS $CFLAGS -I$srcdir">> +AC_RUN_IFELSE([AC_LANG_SOURCE([[>> +int main () {>> + /* check default cflags */>> + #ifndef __mips_loongson_mmi>> + /* No -mloongson-mmi,-march=loongson3a and -march=loongson2f */>> + return 0;>> + #else>> + #ifdef _MIPS_ARCH_LOONGSON2F>> + /* Has -march=loongson2f */>> + return 0;>> + #else>> + /* Has -mloongson-mmi or -march=loongson3a */>> + return 1;>> + #endif>> + #endif>> +}]])], LS_CFLAGS="-mloongson-mmi", LS_CFLAGS="-march=loongson2f")><o:p> </o:p>>I am sorry. The setting to Loongson2f by default is not done by you.>It is my mistake.><o:p> </o:p>>Anyway, since you are working on that patch:><o:p> </o:p>>In the first patch, you setting 3A/MMI default instead of 2F. If that patch was merged, Debian/OpenWrt>etc will be broken just now.>In fact in most case the set 2F, it will not broken Debian, since the the next link test will fail: 2F cannot>interlink with mips64r2/mips32r2. aka LS_CFLAGS is set to 2F will only break>mips3/mips2 OS.>Set LS_CFLAGS to -mloongson-mmi will break almost *ALL* os.>Is it your mistake?><o:p> </o:p>>In the second patch: you read CPU info from /proc/cpuinfo: WTF><o:p> </o:p>>I asked that you should keep loongson options not set by default serveral times.>In your *3rd* patch, you still keep them set by default.><o:p> </o:p>>I told you that you can determine OS/CC behivors by predefined macros, You still cannot understand after I>have a loooooong talk with you by wechat! WTF.><o:p> </o:p>>Almost (if not all) of Loongson guys are *RUBBISH*.>Let me sign this mail by my PGP key.><o:p> </o:p>>> fi>><o:p> </o:p>>> have_loongson_mmi=no>><o:p> </o:p>>><o:p> </o:p><o:p> </o:p>I really don't know what's your problem.<o:p></o:p>Whether you're still going to be so rude or not, this will be my last reply to you.<o:p></o:p>What I've always trying to tell you is that there is no way to set up the right LS_CFLAGS to enable MMI<o:p></o:p>by compile check if the default CFLAGS doesn't contain MMI-related options.<o:p></o:p>So, that is why you added cc_enable_mmi_2f/3a in your patch, and it will not <o:p></o:p>be set to yes if the default CFLAGS does not contain MMI-related options.<o:p></o:p><o:p> </o:p>What I originally wanted to do was to automatically enable MMI without specifying LS_CFLAGS/CC, <o:p></o:p>but not improving the whole default setting process, they are different things.<o:p></o:p><o:p> </o:p>Your patch improved the MMI configure check, It’s good and I will submit it first.<o:p></o:p><o:p> </o:p></div></body></html>