The current llvm/clang build procedure in samples/bpf/README.rst is
out of date. See below that the links are not accessible any more.
$ git clone http://llvm.org/git/llvm.git
Cloning into 'llvm'...
fatal: unable to access 'http://llvm.org/git/llvm.git/': Maximum (20) redirects followed
$ git clone --depth 1 http://llvm.org/git/clang.git
Cloning into 'clang'...
fatal: unable to access 'http://llvm.org/git/clang.git/': Maximum (20) redirects followed
The llvm community has adopted new ways to build the compiler. There are
different ways to build llvm/clang, the Clang Getting Started page [1] has
one way. As Yonghong said, it is better to just copy the build procedure
in Documentation/bpf/bpf_devel_QA.rst to keep consistent.
I verified the procedure and it is proved to be feasible, so we should
update README.rst to reflect the reality. At the same time, update the
related comment in Makefile.
[1] https://clang.llvm.org/get_started.html
Signed-off-by: Tiezhu Yang <[email protected]>
Acked-by: Yonghong Song <[email protected]>
---
v2: Update the commit message suggested by Yonghong,
thank you very much.
samples/bpf/Makefile | 2 +-
samples/bpf/README.rst | 17 ++++++++++-------
2 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 26fc96c..d061446 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -208,7 +208,7 @@ TPROGLDLIBS_xdpsock += -pthread -lcap
TPROGLDLIBS_xsk_fwd += -pthread
# Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
-# make M=samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
+# make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang
LLC ?= llc
CLANG ?= clang
OPT ?= opt
diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst
index dd34b2d..d1be438 100644
--- a/samples/bpf/README.rst
+++ b/samples/bpf/README.rst
@@ -65,17 +65,20 @@ To generate a smaller llc binary one can use::
Quick sniplet for manually compiling LLVM and clang
(build dependencies are cmake and gcc-c++)::
- $ git clone http://llvm.org/git/llvm.git
- $ cd llvm/tools
- $ git clone --depth 1 http://llvm.org/git/clang.git
- $ cd ..; mkdir build; cd build
- $ cmake .. -DLLVM_TARGETS_TO_BUILD="BPF;X86"
- $ make -j $(getconf _NPROCESSORS_ONLN)
+ $ git clone https://github.com/llvm/llvm-project.git
+ $ mkdir -p llvm-project/llvm/build/install
+ $ cd llvm-project/llvm/build
+ $ cmake .. -G "Ninja" -DLLVM_TARGETS_TO_BUILD="BPF;X86" \
+ -DLLVM_ENABLE_PROJECTS="clang" \
+ -DBUILD_SHARED_LIBS=OFF \
+ -DCMAKE_BUILD_TYPE=Release \
+ -DLLVM_BUILD_RUNTIME=OFF
+ $ ninja
It is also possible to point make to the newly compiled 'llc' or
'clang' command via redefining LLC or CLANG on the make command line::
- make M=samples/bpf LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
+ make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang
Cross compiling samples
-----------------------
--
2.1.0
On 2021-01-19, Tiezhu Yang wrote:
>The current llvm/clang build procedure in samples/bpf/README.rst is
>out of date. See below that the links are not accessible any more.
>
>$ git clone http://llvm.org/git/llvm.git
>Cloning into 'llvm'...
>fatal: unable to access 'http://llvm.org/git/llvm.git/': Maximum (20) redirects followed
>$ git clone --depth 1 http://llvm.org/git/clang.git
>Cloning into 'clang'...
>fatal: unable to access 'http://llvm.org/git/clang.git/': Maximum (20) redirects followed
>
>The llvm community has adopted new ways to build the compiler. There are
>different ways to build llvm/clang, the Clang Getting Started page [1] has
>one way. As Yonghong said, it is better to just copy the build procedure
>in Documentation/bpf/bpf_devel_QA.rst to keep consistent.
>
>I verified the procedure and it is proved to be feasible, so we should
>update README.rst to reflect the reality. At the same time, update the
>related comment in Makefile.
>
>[1] https://clang.llvm.org/get_started.html
>
>Signed-off-by: Tiezhu Yang <[email protected]>
>Acked-by: Yonghong Song <[email protected]>
>---
>
>v2: Update the commit message suggested by Yonghong,
> thank you very much.
>
> samples/bpf/Makefile | 2 +-
> samples/bpf/README.rst | 17 ++++++++++-------
> 2 files changed, 11 insertions(+), 8 deletions(-)
>
>diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
>index 26fc96c..d061446 100644
>--- a/samples/bpf/Makefile
>+++ b/samples/bpf/Makefile
>@@ -208,7 +208,7 @@ TPROGLDLIBS_xdpsock += -pthread -lcap
> TPROGLDLIBS_xsk_fwd += -pthread
>
> # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
>-# make M=samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
>+# make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang
> LLC ?= llc
> CLANG ?= clang
> OPT ?= opt
>diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst
>index dd34b2d..d1be438 100644
>--- a/samples/bpf/README.rst
>+++ b/samples/bpf/README.rst
>@@ -65,17 +65,20 @@ To generate a smaller llc binary one can use::
> Quick sniplet for manually compiling LLVM and clang
> (build dependencies are cmake and gcc-c++)::
>
>- $ git clone http://llvm.org/git/llvm.git
>- $ cd llvm/tools
>- $ git clone --depth 1 http://llvm.org/git/clang.git
>- $ cd ..; mkdir build; cd build
>- $ cmake .. -DLLVM_TARGETS_TO_BUILD="BPF;X86"
>- $ make -j $(getconf _NPROCESSORS_ONLN)
>+ $ git clone https://github.com/llvm/llvm-project.git
>+ $ mkdir -p llvm-project/llvm/build/install
llvm-project/llvm/build/install is not used.
>+ $ cd llvm-project/llvm/build
>+ $ cmake .. -G "Ninja" -DLLVM_TARGETS_TO_BUILD="BPF;X86" \
>+ -DLLVM_ENABLE_PROJECTS="clang" \
>+ -DBUILD_SHARED_LIBS=OFF \
-DBUILD_SHARED_LIBS=OFF is the default. It can be omitted.
>+ -DCMAKE_BUILD_TYPE=Release \
>+ -DLLVM_BUILD_RUNTIME=OFF
-DLLVM_BUILD_RUNTIME=OFF can be omitted if none of
compiler-rt/libc++/libc++abi is built.
>+ $ ninja
>
> It is also possible to point make to the newly compiled 'llc' or
> 'clang' command via redefining LLC or CLANG on the make command line::
>
>- make M=samples/bpf LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
>+ make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang
>
> Cross compiling samples
> -----------------------
>--
>2.1.0
>
>--
>You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
>To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
>To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/1611042978-21473-1-git-send-email-yangtiezhu%40loongson.cn.
On 01/20/2021 05:58 AM, Fangrui Song wrote:
> On 2021-01-19, Tiezhu Yang wrote:
>> The current llvm/clang build procedure in samples/bpf/README.rst is
>> out of date. See below that the links are not accessible any more.
>>
>> $ git clone http://llvm.org/git/llvm.git
>> Cloning into 'llvm'...
>> fatal: unable to access 'http://llvm.org/git/llvm.git/': Maximum (20)
>> redirects followed
>> $ git clone --depth 1 http://llvm.org/git/clang.git
>> Cloning into 'clang'...
>> fatal: unable to access 'http://llvm.org/git/clang.git/': Maximum
>> (20) redirects followed
>>
>> The llvm community has adopted new ways to build the compiler. There are
>> different ways to build llvm/clang, the Clang Getting Started page
>> [1] has
>> one way. As Yonghong said, it is better to just copy the build procedure
>> in Documentation/bpf/bpf_devel_QA.rst to keep consistent.
>>
>> I verified the procedure and it is proved to be feasible, so we should
>> update README.rst to reflect the reality. At the same time, update the
>> related comment in Makefile.
>>
>> [1] https://clang.llvm.org/get_started.html
>>
>> Signed-off-by: Tiezhu Yang <[email protected]>
>> Acked-by: Yonghong Song <[email protected]>
>> ---
>>
>> v2: Update the commit message suggested by Yonghong,
>> thank you very much.
>>
>> samples/bpf/Makefile | 2 +-
>> samples/bpf/README.rst | 17 ++++++++++-------
>> 2 files changed, 11 insertions(+), 8 deletions(-)
>>
>> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
>> index 26fc96c..d061446 100644
>> --- a/samples/bpf/Makefile
>> +++ b/samples/bpf/Makefile
>> @@ -208,7 +208,7 @@ TPROGLDLIBS_xdpsock += -pthread -lcap
>> TPROGLDLIBS_xsk_fwd += -pthread
>>
>> # Allows pointing LLC/CLANG to a LLVM backend with bpf support,
>> redefine on cmdline:
>> -# make M=samples/bpf/ LLC=~/git/llvm/build/bin/llc
>> CLANG=~/git/llvm/build/bin/clang
>> +# make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc
>> CLANG=~/git/llvm-project/llvm/build/bin/clang
>> LLC ?= llc
>> CLANG ?= clang
>> OPT ?= opt
>> diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst
>> index dd34b2d..d1be438 100644
>> --- a/samples/bpf/README.rst
>> +++ b/samples/bpf/README.rst
>> @@ -65,17 +65,20 @@ To generate a smaller llc binary one can use::
>> Quick sniplet for manually compiling LLVM and clang
>> (build dependencies are cmake and gcc-c++)::
>>
>> - $ git clone http://llvm.org/git/llvm.git
>> - $ cd llvm/tools
>> - $ git clone --depth 1 http://llvm.org/git/clang.git
>> - $ cd ..; mkdir build; cd build
>> - $ cmake .. -DLLVM_TARGETS_TO_BUILD="BPF;X86"
>> - $ make -j $(getconf _NPROCESSORS_ONLN)
>> + $ git clone https://github.com/llvm/llvm-project.git
>> + $ mkdir -p llvm-project/llvm/build/install
>
> llvm-project/llvm/build/install is not used.
Yes, just mkdir -p llvm-project/llvm/build is OK.
>
>> + $ cd llvm-project/llvm/build
>> + $ cmake .. -G "Ninja" -DLLVM_TARGETS_TO_BUILD="BPF;X86" \
>> + -DLLVM_ENABLE_PROJECTS="clang" \
>> + -DBUILD_SHARED_LIBS=OFF \
>
> -DBUILD_SHARED_LIBS=OFF is the default. It can be omitted.
I search the related doc [1] [2], remove this option is OK for me.
BUILD_SHARED_LIBS:BOOL
Flag indicating if each LLVM component (e.g. Support) is built as a
shared library (ON) or as a static library (OFF). Its default value is OFF.
[1] https://www.llvm.org/docs/CMake.html
[2] https://cmake.org/cmake/help/latest/variable/BUILD_SHARED_LIBS.html
>
>> + -DCMAKE_BUILD_TYPE=Release \
>> + -DLLVM_BUILD_RUNTIME=OFF
>
> -DLLVM_BUILD_RUNTIME=OFF can be omitted if none of
> compiler-rt/libc++/libc++abi is built.
I am not very sure about it because the default value of
LLVM_BUILD_RUNTIME is ON? [3]
option(LLVM_BUILD_RUNTIME
"Build the LLVM runtime libraries." ON)
[3] https://github.com/llvm/llvm-project/blob/main/llvm/CMakeLists.txt
If anyone has any more suggestions, please let me know.
I will send v3 after waiting for other feedback.
By the way, Documentation/bpf/bpf_devel_QA.rst maybe need a separate
patch to remove some cmake options?
Thanks,
Tiezhu
>
>> + $ ninja
>>
>> It is also possible to point make to the newly compiled 'llc' or
>> 'clang' command via redefining LLC or CLANG on the make command line::
>>
>> - make M=samples/bpf LLC=~/git/llvm/build/bin/llc
>> CLANG=~/git/llvm/build/bin/clang
>> + make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc
>> CLANG=~/git/llvm-project/llvm/build/bin/clang
>>
>> Cross compiling samples
>> -----------------------
>> --
>> 2.1.0
>>
>> --
>> You received this message because you are subscribed to the Google
>> Groups "Clang Built Linux" group.
>> To unsubscribe from this group and stop receiving emails from it,
>> send an email to [email protected].
>> To view this discussion on the web visit
>> https://groups.google.com/d/msgid/clang-built-linux/1611042978-21473-1-git-send-email-yangtiezhu%40loongson.cn.
On 01/20/2021 10:43 AM, Nick Desaulniers wrote:
> On Mon, Jan 18, 2021 at 11:56 PM Tiezhu Yang <[email protected]> wrote:
>> The current llvm/clang build procedure in samples/bpf/README.rst is
>> out of date. See below that the links are not accessible any more.
>>
>> $ git clone http://llvm.org/git/llvm.git
>> Cloning into 'llvm'...
>> fatal: unable to access 'http://llvm.org/git/llvm.git/': Maximum (20) redirects followed
>> $ git clone --depth 1 http://llvm.org/git/clang.git
>> Cloning into 'clang'...
>> fatal: unable to access 'http://llvm.org/git/clang.git/': Maximum (20) redirects followed
>>
>> The llvm community has adopted new ways to build the compiler. There are
>> different ways to build llvm/clang, the Clang Getting Started page [1] has
>> one way. As Yonghong said, it is better to just copy the build procedure
>> in Documentation/bpf/bpf_devel_QA.rst to keep consistent.
>>
>> I verified the procedure and it is proved to be feasible, so we should
>> update README.rst to reflect the reality. At the same time, update the
>> related comment in Makefile.
>>
>> [1] https://clang.llvm.org/get_started.html
> There's also https://www.kernel.org/doc/html/latest/kbuild/llvm.html#getting-llvm
> (could cross link in rst/sphinx).
>
>> Signed-off-by: Tiezhu Yang <[email protected]>
>> Acked-by: Yonghong Song <[email protected]>
>> ---
>>
>> v2: Update the commit message suggested by Yonghong,
>> thank you very much.
>>
>> samples/bpf/Makefile | 2 +-
>> samples/bpf/README.rst | 17 ++++++++++-------
>> 2 files changed, 11 insertions(+), 8 deletions(-)
>>
>> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
>> index 26fc96c..d061446 100644
>> --- a/samples/bpf/Makefile
>> +++ b/samples/bpf/Makefile
>> @@ -208,7 +208,7 @@ TPROGLDLIBS_xdpsock += -pthread -lcap
>> TPROGLDLIBS_xsk_fwd += -pthread
>>
>> # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
>> -# make M=samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
>> +# make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang
>> LLC ?= llc
>> CLANG ?= clang
>> OPT ?= opt
>> diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst
>> index dd34b2d..d1be438 100644
>> --- a/samples/bpf/README.rst
>> +++ b/samples/bpf/README.rst
>> @@ -65,17 +65,20 @@ To generate a smaller llc binary one can use::
>> Quick sniplet for manually compiling LLVM and clang
>> (build dependencies are cmake and gcc-c++)::
>>
>> - $ git clone http://llvm.org/git/llvm.git
>> - $ cd llvm/tools
>> - $ git clone --depth 1 http://llvm.org/git/clang.git
>> - $ cd ..; mkdir build; cd build
>> - $ cmake .. -DLLVM_TARGETS_TO_BUILD="BPF;X86"
> Is the BPF target not yet on by default?
The default value includes BPF.
> I frown upon disabling other backends.
I think the initial aim of the build procedure in samples/bpf/README.rst [1]
is a simple and quick start guide:
[ To generate a smaller llc binary one can use:
-DLLVM_TARGETS_TO_BUILD="BPF" ]
[1] https://github.com/torvalds/linux/blob/master/samples/bpf/README.rst
>
>> - $ make -j $(getconf _NPROCESSORS_ONLN)
>> + $ git clone https://github.com/llvm/llvm-project.git
>> + $ mkdir -p llvm-project/llvm/build/install
>> + $ cd llvm-project/llvm/build
>> + $ cmake .. -G "Ninja" -DLLVM_TARGETS_TO_BUILD="BPF;X86" \
>> + -DLLVM_ENABLE_PROJECTS="clang" \
>> + -DBUILD_SHARED_LIBS=OFF \
>> + -DCMAKE_BUILD_TYPE=Release \
>> + -DLLVM_BUILD_RUNTIME=OFF
>> + $ ninja
>>
>> It is also possible to point make to the newly compiled 'llc' or
>> 'clang' command via redefining LLC or CLANG on the make command line::
>>
>> - make M=samples/bpf LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
>> + make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang
>>
>> Cross compiling samples
>> -----------------------
>> --
>> 2.1.0
>>
>> --
>> You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
>> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
>> To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/1611042978-21473-1-git-send-email-yangtiezhu%40loongson.cn.
>
>
On 1/19/21 6:32 PM, Tiezhu Yang wrote:
> On 01/20/2021 05:58 AM, Fangrui Song wrote:
>> On 2021-01-19, Tiezhu Yang wrote:
>>> The current llvm/clang build procedure in samples/bpf/README.rst is
>>> out of date. See below that the links are not accessible any more.
>>>
>>> $ git clone
>>> http://llvm.org/git/llvm.git
>>> Cloning into 'llvm'...
>>> fatal: unable to access
>>> 'http://llvm.org/git/llvm.git/
>>> ': Maximum (20) redirects followed
>>> $ git clone --depth 1
>>> http://llvm.org/git/clang.git
>>> Cloning into 'clang'...
>>> fatal: unable to access
>>> 'http://llvm.org/git/clang.git/
>>> ': Maximum (20) redirects followed
>>>
>>> The llvm community has adopted new ways to build the compiler. There are
>>> different ways to build llvm/clang, the Clang Getting Started page
>>> [1] has
>>> one way. As Yonghong said, it is better to just copy the build procedure
>>> in Documentation/bpf/bpf_devel_QA.rst to keep consistent.
>>>
>>> I verified the procedure and it is proved to be feasible, so we should
>>> update README.rst to reflect the reality. At the same time, update the
>>> related comment in Makefile.
>>>
>>> [1]
>>> https://clang.llvm.org/get_started.html
>>>
>>> Signed-off-by: Tiezhu Yang <[email protected]>
>>> Acked-by: Yonghong Song <[email protected]>
>>> ---
>>>
>>> v2: Update the commit message suggested by Yonghong,
>>> thank you very much.
>>>
>>> samples/bpf/Makefile | 2 +-
>>> samples/bpf/README.rst | 17 ++++++++++-------
>>> 2 files changed, 11 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
>>> index 26fc96c..d061446 100644
>>> --- a/samples/bpf/Makefile
>>> +++ b/samples/bpf/Makefile
>>> @@ -208,7 +208,7 @@ TPROGLDLIBS_xdpsock += -pthread -lcap
>>> TPROGLDLIBS_xsk_fwd += -pthread
>>>
>>> # Allows pointing LLC/CLANG to a LLVM backend with bpf support,
>>> redefine on cmdline:
>>> -# make M=samples/bpf/ LLC=~/git/llvm/build/bin/llc
>>> CLANG=~/git/llvm/build/bin/clang
>>> +# make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc
>>> CLANG=~/git/llvm-project/llvm/build/bin/clang
>>> LLC ?= llc
>>> CLANG ?= clang
>>> OPT ?= opt
>>> diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst
>>> index dd34b2d..d1be438 100644
>>> --- a/samples/bpf/README.rst
>>> +++ b/samples/bpf/README.rst
>>> @@ -65,17 +65,20 @@ To generate a smaller llc binary one can use::
>>> Quick sniplet for manually compiling LLVM and clang
>>> (build dependencies are cmake and gcc-c++)::
>>>
>>> - $ git clone
>>> http://llvm.org/git/llvm.git
>>> - $ cd llvm/tools
>>> - $ git clone --depth 1
>>> http://llvm.org/git/clang.git
>>> - $ cd ..; mkdir build; cd build
>>> - $ cmake .. -DLLVM_TARGETS_TO_BUILD="BPF;X86"
>>> - $ make -j $(getconf _NPROCESSORS_ONLN)
>>> + $ git clone https://github.com/llvm/llvm-project.git
>>> + $ mkdir -p llvm-project/llvm/build/install
>>
>> llvm-project/llvm/build/install is not used.
>
> Yes, just mkdir -p llvm-project/llvm/build is OK.
>
>>
>>> + $ cd llvm-project/llvm/build
>>> + $ cmake .. -G "Ninja" -DLLVM_TARGETS_TO_BUILD="BPF;X86" \
>>> + -DLLVM_ENABLE_PROJECTS="clang" \
>>> + -DBUILD_SHARED_LIBS=OFF \
>>
>> -DBUILD_SHARED_LIBS=OFF is the default. It can be omitted.
>
> I search the related doc [1] [2], remove this option is OK for me.
>
> BUILD_SHARED_LIBS:BOOL
>
> Flag indicating if each LLVM component (e.g. Support) is built as a
> shared library (ON) or as a static library (OFF). Its default value is OFF.
>
> [1]
> https://www.llvm.org/docs/CMake.html
> [2]
> https://cmake.org/cmake/help/latest/variable/BUILD_SHARED_LIBS.html
>
>>
>>> + -DCMAKE_BUILD_TYPE=Release \
>>> + -DLLVM_BUILD_RUNTIME=OFF
>>
>> -DLLVM_BUILD_RUNTIME=OFF can be omitted if none of
>> compiler-rt/libc++/libc++abi is built.
>
> I am not very sure about it because the default value of
> LLVM_BUILD_RUNTIME is ON? [3]
>
> option(LLVM_BUILD_RUNTIME
> "Build the LLVM runtime libraries." ON)
>
> [3] https://github.com/llvm/llvm-project/blob/main/llvm/CMakeLists.txt
>
> If anyone has any more suggestions, please let me know.
> I will send v3 after waiting for other feedback.
>
> By the way, Documentation/bpf/bpf_devel_QA.rst maybe need a separate
> patch to remove some cmake options?
Please submit updated this patch and Documentation/bpf/bpf_devel_QA.rst
together. This way, it is easy to cross check. Thanks.
>
> Thanks,
> Tiezhu
>
[...]
On Mon, Jan 18, 2021 at 11:56 PM Tiezhu Yang <[email protected]> wrote:
>
> The current llvm/clang build procedure in samples/bpf/README.rst is
> out of date. See below that the links are not accessible any more.
>
> $ git clone http://llvm.org/git/llvm.git
> Cloning into 'llvm'...
> fatal: unable to access 'http://llvm.org/git/llvm.git/': Maximum (20) redirects followed
> $ git clone --depth 1 http://llvm.org/git/clang.git
> Cloning into 'clang'...
> fatal: unable to access 'http://llvm.org/git/clang.git/': Maximum (20) redirects followed
>
> The llvm community has adopted new ways to build the compiler. There are
> different ways to build llvm/clang, the Clang Getting Started page [1] has
> one way. As Yonghong said, it is better to just copy the build procedure
> in Documentation/bpf/bpf_devel_QA.rst to keep consistent.
>
> I verified the procedure and it is proved to be feasible, so we should
> update README.rst to reflect the reality. At the same time, update the
> related comment in Makefile.
>
> [1] https://clang.llvm.org/get_started.html
There's also https://www.kernel.org/doc/html/latest/kbuild/llvm.html#getting-llvm
(could cross link in rst/sphinx).
>
> Signed-off-by: Tiezhu Yang <[email protected]>
> Acked-by: Yonghong Song <[email protected]>
> ---
>
> v2: Update the commit message suggested by Yonghong,
> thank you very much.
>
> samples/bpf/Makefile | 2 +-
> samples/bpf/README.rst | 17 ++++++++++-------
> 2 files changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
> index 26fc96c..d061446 100644
> --- a/samples/bpf/Makefile
> +++ b/samples/bpf/Makefile
> @@ -208,7 +208,7 @@ TPROGLDLIBS_xdpsock += -pthread -lcap
> TPROGLDLIBS_xsk_fwd += -pthread
>
> # Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:
> -# make M=samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
> +# make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang
> LLC ?= llc
> CLANG ?= clang
> OPT ?= opt
> diff --git a/samples/bpf/README.rst b/samples/bpf/README.rst
> index dd34b2d..d1be438 100644
> --- a/samples/bpf/README.rst
> +++ b/samples/bpf/README.rst
> @@ -65,17 +65,20 @@ To generate a smaller llc binary one can use::
> Quick sniplet for manually compiling LLVM and clang
> (build dependencies are cmake and gcc-c++)::
>
> - $ git clone http://llvm.org/git/llvm.git
> - $ cd llvm/tools
> - $ git clone --depth 1 http://llvm.org/git/clang.git
> - $ cd ..; mkdir build; cd build
> - $ cmake .. -DLLVM_TARGETS_TO_BUILD="BPF;X86"
Is the BPF target not yet on by default? I frown upon disabling other backends.
> - $ make -j $(getconf _NPROCESSORS_ONLN)
> + $ git clone https://github.com/llvm/llvm-project.git
> + $ mkdir -p llvm-project/llvm/build/install
> + $ cd llvm-project/llvm/build
> + $ cmake .. -G "Ninja" -DLLVM_TARGETS_TO_BUILD="BPF;X86" \
> + -DLLVM_ENABLE_PROJECTS="clang" \
> + -DBUILD_SHARED_LIBS=OFF \
> + -DCMAKE_BUILD_TYPE=Release \
> + -DLLVM_BUILD_RUNTIME=OFF
> + $ ninja
>
> It is also possible to point make to the newly compiled 'llc' or
> 'clang' command via redefining LLC or CLANG on the make command line::
>
> - make M=samples/bpf LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang
> + make M=samples/bpf LLC=~/git/llvm-project/llvm/build/bin/llc CLANG=~/git/llvm-project/llvm/build/bin/clang
>
> Cross compiling samples
> -----------------------
> --
> 2.1.0
>
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--
Thanks,
~Nick Desaulniers