[examples] Update Whisper README doc.

examples/BuddyWhisper/README.md

@@ -5,12 +5,62 @@ This example shows how to use Buddy Compiler to compile a WHISPER model to MLIR
 
 
 ## How to run
-1. Ensure that LLVM, Buddy Compiler and the Buddy Compiler python packages are installed properly. You can refer to [here](https://github.com/buddy-compiler/buddy-mlir) for more information and do a double check.
 
-2. Set the `PYTHONPATH` environment variable.
+0. Enter Python virtual environment.
+
+We recommend you to use anaconda3 to create python virtual environment. You should install python packages as buddy-mlir/requirements.
+
+```
+$ conda activate <your virtual environment name>
+$ cd buddy-mlir
+$ pip install -r requirements.txt
+```
+
+1. Build and check LLVM/MLIR
+
+```
+$ cd buddy-mlir
+$ mkdir llvm/build
+$ cd llvm/build
+$ cmake -G Ninja ../llvm \
+    -DLLVM_ENABLE_PROJECTS="mlir;clang;openmp" \
+    -DLLVM_TARGETS_TO_BUILD="host;RISCV" \
+    -DLLVM_ENABLE_ASSERTIONS=ON \
+    -DOPENMP_ENABLE_LIBOMPTARGET=OFF \
+    -DCMAKE_BUILD_TYPE=RELEASE \
+    -DMLIR_ENABLE_BINDINGS_PYTHON=ON \
+    -DPython3_EXECUTABLE=$(which python3)
+$ ninja check-clang check-mlir omp
+```
+
+2. Build and check buddy-mlir
+
+```
+$ cd buddy-mlir
+$ mkdir build
+$ cd build
+$ cmake -G Ninja .. \
+    -DMLIR_DIR=$PWD/../llvm/build/lib/cmake/mlir \
+    -DLLVM_DIR=$PWD/../llvm/build/lib/cmake/llvm \
+    -DLLVM_ENABLE_ASSERTIONS=ON \
+    -DCMAKE_BUILD_TYPE=RELEASE \
+    -DBUDDY_MLIR_ENABLE_PYTHON_PACKAGES=ON \
+    -DPython3_EXECUTABLE=$(which python3)
+$ ninja
+$ ninja check-buddy
+```
+
+Set the `PYTHONPATH` environment variable. Make sure that the `PYTHONPATH` variable includes the directory of LLVM/MLIR python bindings and the directory of Buddy MLIR python packages.
 
 ```bash
 $ export PYTHONPATH=/path-to-buddy-mlir/llvm/build/tools/mlir/python_packages/mlir_core:/path-to-buddy-mlir/build/python_packages:${PYTHONPATH}
+
+// For example:
+// Navigate to your buddy-mlir/build directory
+$ cd buddy-mlir/build
+$ export BUDDY_MLIR_BUILD_DIR=$PWD
+$ export LLVM_MLIR_BUILD_DIR=$PWD/../llvm/build
+$ export PYTHONPATH=${LLVM_MLIR_BUILD_DIR}/tools/mlir/python_packages/mlir_core:${BUDDY_MLIR_BUILD_DIR}/python_packages:${PYTHONPATH}
 ```
 
 3. Set model and dataset environment variable.