Index: llvm/utils/release/build_llvm_release.bat
===================================================================
--- llvm/utils/release/build_llvm_release.bat
+++ llvm/utils/release/build_llvm_release.bat
@@ -60,7 +60,7 @@
 
 set revision=llvmorg-%1
 set package_version=%1
-set build_dir=llvm_package_%package_version%
+set build_dir=%cd%\llvm_package_%package_version%
 
 echo Revision: %revision%
 echo Package version: %package_version%
@@ -68,6 +68,11 @@
 echo.
 pause
 
+if exist %build_dir% (
+  REM Exit if the build directory already exists.
+  echo Build directory already exists: %build_dir%
+  exit /b
+)
 mkdir %build_dir%
 cd %build_dir%
 
@@ -76,8 +81,12 @@
 7z x src.zip || exit /b
 mv llvm-project-* llvm-project || exit /b
 
+curl -O https://gitlab.gnome.org/GNOME/libxml2/-/archive/v2.9.12/libxml2-v2.9.12.tar.gz || exit /b
+tar zxf libxml2-v2.9.12.tar.gz
+
 REM Setting CMAKE_CL_SHOWINCLUDES_PREFIX to work around PR27226.
-set cmake_flags=^
+REM Common flags for both 32/64 builds.
+set common_cmake_flags=^
   -DCMAKE_BUILD_TYPE=Release ^
   -DLLVM_ENABLE_ASSERTIONS=OFF ^
   -DLLVM_INSTALL_TOOLCHAIN_ONLY=ON ^
@@ -87,7 +96,6 @@
   -DPACKAGE_VERSION=%package_version% ^
   -DLLDB_RELOCATABLE_PYTHON=1 ^
   -DLLDB_EMBED_PYTHON_HOME=OFF ^
-  -DLLDB_TEST_COMPILER=%cd%\build32_stage0\bin\clang.exe ^
   -DCMAKE_CL_SHOWINCLUDES_PREFIX="Note: including file: " ^
   -DLLVM_ENABLE_LIBXML2=FORCE_ON ^
   -DLLDB_ENABLE_LIBXML2=OFF ^
@@ -95,18 +103,29 @@
   -DCMAKE_CXX_FLAGS="-DLIBXML_STATIC" ^
   -DLLVM_ENABLE_PROJECTS="clang;clang-tools-extra;lld;compiler-rt;lldb;openmp"
 
-REM TODO: Run the "check-all" tests.
-
+REM Preserve original path
 set OLDPATH=%PATH%
 
-curl -O https://gitlab.gnome.org/GNOME/libxml2/-/archive/v2.9.12/libxml2-v2.9.12.tar.gz || exit /b
-tar zxf libxml2-v2.9.12.tar.gz
+REM Build the 32-bits and/or 64-bits binaries.
+call :do_build_32
+call :do_build_64
+goto :eof
+
+::==============================================================================
+:: Build 32-bits binaries.
+::==============================================================================
+:do_build_32
+REM Restore original path
+set PATH=%OLDPATH%
+
+REM TODO: Run the "check-all" tests.
 
-set "VSCMD_START_DIR=%CD%"
+REM Set Python environment
+set PYTHONHOME=%python32_dir%
+set PATH=%PYTHONHOME%;%PATH%
+
+set "VSCMD_START_DIR=%build_dir%"
 call "%vsdevcmd%" -arch=x86
-set PATH=%python32_dir%;%PATH%
-set CC=
-set CXX=
 mkdir build32_stage0
 cd build32_stage0
 
@@ -118,8 +137,18 @@
 set "libxmldir=%libxmldir:\=/%"
 cd ..
 
-cmake -GNinja %cmake_flags% -DPYTHON_HOME=%python32_dir% -DPython3_ROOT_DIR=%python32_dir% -DLIBXML2_INCLUDE_DIR=%libxmldir%/include/libxml2 -DLIBXML2_LIBRARIES=%libxmldir%/lib/libxml2s.lib ..\llvm-project\llvm || exit /b
-
+REM Stage0 binaries directory; used in stage1.
+set "stage0_bin_dir=%build_dir%/build32_stage0/bin"
+set cmake_flags=^
+  %common_cmake_flags% ^
+  -DLLDB_TEST_COMPILER=%stage0_bin_dir%/clang.exe ^
+  -DPYTHON_HOME=%PYTHONHOME% ^
+  -DPython3_ROOT_DIR=%PYTHONHOME% ^
+  -DPYTHON_EXECUTABLE=%PYTHONHOME%\python.exe ^
+  -DLIBXML2_INCLUDE_DIRS=%libxmldir%/include/libxml2 ^
+  -DLIBXML2_LIBRARIES=%libxmldir%/lib/libxml2s.lib
+
+cmake -GNinja %cmake_flags% ..\llvm-project\llvm || exit /b
 ninja || ninja || ninja || exit /b
 REM ninja check-llvm || ninja check-llvm || ninja check-llvm || exit /b
 REM ninja check-clang || ninja check-clang || ninja check-clang || exit /b
@@ -128,11 +157,17 @@
 REM ninja check-clang-tools || ninja check-clang-tools || ninja check-clang-tools || exit /b
 cd..
 
+REM CMake expects the paths that specifies the compiler and linker to be
+REM with forward slash.
+set all_cmake_flags=^
+  %cmake_flags% ^
+  -DCMAKE_C_COMPILER=%stage0_bin_dir%/clang-cl.exe ^
+  -DCMAKE_CXX_COMPILER=%stage0_bin_dir%/clang-cl.exe
+set cmake_flags=%all_cmake_flags:\=/%
+
 mkdir build32
 cd build32
-set CC=..\build32_stage0\bin\clang-cl
-set CXX=..\build32_stage0\bin\clang-cl
-cmake -GNinja %cmake_flags% -DPYTHON_HOME=%python32_dir% -DPython3_ROOT_DIR=%python32_dir% -DLIBXML2_INCLUDE_DIR=%libxmldir%/include/libxml2 -DLIBXML2_LIBRARIES=%libxmldir%/lib/libxml2s.lib ..\llvm-project\llvm || exit /b
+cmake -GNinja %cmake_flags% ..\llvm-project\llvm || exit /b
 ninja || ninja || ninja || exit /b
 REM ninja check-llvm || ninja check-llvm || ninja check-llvm || exit /b
 REM ninja check-clang || ninja check-clang || ninja check-clang || exit /b
@@ -142,12 +177,22 @@
 ninja package || exit /b
 cd ..
 
-set "VSCMD_START_DIR=%CD%"
+exit /b
+::==============================================================================
+
+::==============================================================================
+:: Build 64-bits binaries.
+::==============================================================================
+:do_build_64
+REM Restore original path
 set PATH=%OLDPATH%
+
+REM Set Python environment
+set PYTHONHOME=%python64_dir%
+set PATH=%PYTHONHOME%;%PATH%
+
+set "VSCMD_START_DIR=%build_dir%"
 call "%vsdevcmd%" -arch=amd64
-set PATH=%python64_dir%;%PATH%
-set CC=
-set CXX=
 mkdir build64_stage0
 cd build64_stage0
 
@@ -159,7 +204,18 @@
 set "libxmldir=%libxmldir:\=/%"
 cd ..
 
-cmake -GNinja %cmake_flags% -DPYTHON_HOME=%python64_dir% -DPython3_ROOT_DIR=%python64_dir% -DLIBXML2_INCLUDE_DIR=%libxmldir%/include/libxml2 -DLIBXML2_LIBRARIES=%libxmldir%/lib/libxml2s.lib ..\llvm-project\llvm || exit /b
+REM Stage0 binaries directory; used in stage1.
+set "stage0_bin_dir=%build_dir%/build64_stage0/bin"
+set cmake_flags=^
+  %common_cmake_flags% ^
+  -DLLDB_TEST_COMPILER=%stage0_bin_dir%/clang.exe ^
+  -DPYTHON_HOME=%PYTHONHOME% ^
+  -DPython3_ROOT_DIR=%PYTHONHOME% ^
+  -DPYTHON_EXECUTABLE=%PYTHONHOME%\python.exe ^
+  -DLIBXML2_INCLUDE_DIRS=%libxmldir%/include/libxml2 ^
+  -DLIBXML2_LIBRARIES=%libxmldir%/lib/libxml2s.lib
+
+cmake -GNinja %cmake_flags% ..\llvm-project\llvm || exit /b
 ninja || ninja || ninja || exit /b
 ninja check-llvm || ninja check-llvm || ninja check-llvm || exit /b
 ninja check-clang || ninja check-clang || ninja check-clang || exit /b
@@ -169,11 +225,17 @@
 ninja check-clangd || ninja check-clangd || ninja check-clangd || exit /b
 cd..
 
+REM CMake expects the paths that specifies the compiler and linker to be
+REM with forward slash.
+set all_cmake_flags=^
+  %cmake_flags% ^
+  -DCMAKE_C_COMPILER=%stage0_bin_dir%/clang-cl.exe ^
+  -DCMAKE_CXX_COMPILER=%stage0_bin_dir%/clang-cl.exe
+set cmake_flags=%all_cmake_flags:\=/%
+
 mkdir build64
 cd build64
-set CC=..\build64_stage0\bin\clang-cl
-set CXX=..\build64_stage0\bin\clang-cl
-cmake -GNinja %cmake_flags% -DPYTHON_HOME=%python64_dir% -DPython3_ROOT_DIR=%python64_dir% -DLIBXML2_INCLUDE_DIR=%libxmldir%/include/libxml2 -DLIBXML2_LIBRARIES=%libxmldir%/lib/libxml2s.lib ..\llvm-project\llvm || exit /b
+cmake -GNinja %cmake_flags% ..\llvm-project\llvm || exit /b
 ninja || ninja || ninja || exit /b
 ninja check-llvm || ninja check-llvm || ninja check-llvm || exit /b
 ninja check-clang || ninja check-clang || ninja check-clang || exit /b
@@ -183,3 +245,6 @@
 ninja check-clangd || ninja check-clangd || ninja check-clangd || exit /b
 ninja package || exit /b
 cd ..
+
+exit /b
+::==============================================================================