Added a faster method to clone llvm project [DOCS]

[amccarth]

clang/www/get_started.html

54

Can you explain what the trade-off is? If this is always faster and most of us only ever build the latest version (unless doing a bisect), why should anyone ever choose the slow way?

I don't know enough about git to know whether there are ramifications to truncating the history. If someone starts with --depth=1 and then later becomes a contributor, will having truncated history impact the code review and patch submission workflow?

+nit: no space before the :

[sushmaunnibhavi]

clang/www/get_started.html

54

For normal users looking to just compile, this command works fine. But if someone later becomes a contributor, since they can't push code from a shallow clone, it needs to be converted into a full clone using

git fetch –unshallow

[amccarth]

clang/www/get_started.html

54

Sorry, the intent of my questions was to get the trade-off explained in the document itself.

[sushmaunnibhavi]

clang/www/get_started.html

54

To save storage and speed up the checkout time, we may want to do a shallow clone.

[xgupta]

@sushmaunnibhavi Actually, what you wrote in the last two comments, you should write them in clang/www/get_started.html instead of comments. Please update the file.

[sushmaunnibhavi]

Explained why doing a shallow clone is useful.

[xgupta]

Nice suggestion, would you also write your second comment in the doc:

//For normal users looking to just compile, this command works fine. But if someone later becomes a contributor, since they can't push code from a shallow clone, it needs to be converted into a full clone using

git fetch –unshallow//

Because If someone doesn't know about --depth 1, may happen that also don't know about --unshallow. better we suggest here so they don't need to search around on internt.

[xgupta]

This seems good to me, But please wait for @amccarth re-review.

[amccarth]

LGTM. Thanks!

[xgupta]

Thanks @sushmaunnibhavi, I will commit it on your behalf.

clang/www/get_started.html

<li>Standard build process uses CMake. Get it at:
       <a href="https://cmake.org/download/">
       https://cmake.org/download/</a></li>
   </ul>
 
   <li>Check out the LLVM project:
   <ul>
     <li>Change directory to where you want the llvm directory placed.</li>
     <li><tt>git clone https://github.com/llvm/llvm-project.git</tt></li>
+    <li>The above command is very slow. It can be made faster by creating a shallow clone. Shallow clone saves storage and speeds up the checkout time. This is done by using the command:
+      <ul>
+        <li><tt>git clone --depth=1 https://github.com/llvm/llvm-project.git (using this only the latest version of llvm can be built)</tt></li>
+        <li>For normal users looking to just compile, this command works fine. But if someone later becomes a contributor, since they can't push code from a shallow clone, it needs to be converted into a full clone:
+          <ul>
+            <li><tt>cd llvm-project</tt></li>
+            <li><tt>git fetch --unshallow</tt></li>
+          </ul>
+        </li>
+      </ul>
+    </li>
   </ul>
   </li>
   <li>Build LLVM and Clang:
   <ul>
     <li><tt>cd llvm-project</tt></li>
     <li><tt>mkdir build</tt> (in-tree build is not supported)</li>
     <li><tt>cd build</tt></li>
     <li><tt>cmake -DLLVM_ENABLE_PROJECTS=clang -G "Unix Makefiles" ../llvm</tt></li>