Building clang

[Tom Stellard via cfe-dev]

Hi,

What is the fastest way to build clang from source? Currently I am using the following:

```

cmake -DLLVM_ENABLE_PROJECTS="clang" -G "Ninja" ../llvm

ninja

```

Kindly,

Anshil

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[Tom Stellard via cfe-dev]

It's typically a big performance improvement to leverage ccache and to use lld as the linker.

See "LLVM_ENABLE_LLD" and "LLVM_CCACHE_BUILD"  in https://llvm.org/docs/CMake.html#llvm-specific-variables

On Sun, Aug 23, 2020 at 1:12 PM Anshil Gandhi via cfe-dev <[hidden email]> wrote:

Hi,

What is the fastest way to build clang from source? Currently I am using the following:

```

cmake -DLLVM_ENABLE_PROJECTS="clang" -G "Ninja" ../llvm

ninja

```

Kindly,

Anshil

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https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev

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[Tom Stellard via cfe-dev]

On Sun, Aug 23, 2020 at 01:21:30PM -0500, Brian Cain via cfe-dev wrote:
> It's typically a big performance improvement to leverage ccache and to use
> lld as the linker.

Using ccache will normally not result in any performance improvements
for a one-off build and typically even decrease performance. Whether it
helps for update builds is questionable too.

Joerg
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[Tom Stellard via cfe-dev]

To improve speed of building, you may consider the argument DLLVM_BUILD_TESTS (I have OFF for this argument), DLLVM_TARGETS_TO_BUILD (x86 maybe), DLLVM_ENABLE_PROJECTS - select only projects that you need.

Hope that help!

----------------

On Sun, 23 Aug 2020 at 22:55, Joerg Sonnenberger via cfe-dev <[hidden email]> wrote:

On Sun, Aug 23, 2020 at 01:21:30PM -0500, Brian Cain via cfe-dev wrote:
> It's typically a big performance improvement to leverage ccache and to use
> lld as the linker.

Using ccache will normally not result in any performance improvements
for a one-off build and typically even decrease performance. Whether it
helps for update builds is questionable too.

Joerg
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