[BOLT] Update README build instructions
Mehdi spotted that our build instructions don't make sense in a monorepo:
https://github.com/facebookincubator/BOLT/pull/269.
Reviewed By: maksfb
Differential Revision: https://reviews.llvm.org/D117062
diff --git a/bolt/README.md b/bolt/README.md
index cec5942..ca72a4a 100644
--- a/bolt/README.md
+++ b/bolt/README.md
@@ -46,22 +46,19 @@
tools. The build process is not much different from a regular LLVM build.
The following instructions are assuming that you are running under Linux.
-Start with cloning LLVM and BOLT repos:
+Start with cloning LLVM repo:
```
-> git clone https://github.com/facebookincubator/BOLT llvm-bolt
+> git clone https://github.com/llvm/llvm-project.git
> mkdir build
> cd build
-> cmake -G Ninja ../llvm-bolt/llvm -DLLVM_TARGETS_TO_BUILD="X86;AArch64" -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_ENABLE_PROJECTS="clang;lld;bolt"
-> ninja
+> cmake -G Ninja ../llvm-project/llvm -DLLVM_TARGETS_TO_BUILD="X86;AArch64" -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_ASSERTIONS=ON -DLLVM_ENABLE_PROJECTS="bolt"
+> ninja bolt
```
`llvm-bolt` will be available under `bin/`. Add this directory to your path to
ensure the rest of the commands in this tutorial work.
-Note that we use a specific snapshot of LLVM monorepo as we currently
-rely on a set of patches that are not yet upstreamed.
-
## Optimizing BOLT's Performance
BOLT runs many internal passes in parallel. If you foresee heavy usage of
