build-llvm.py: Convert '--debug' into '--build-type'

Right now, the LLVM tests are only runnable when specifying '--debug'.
However, some users want to be able to run the LLVM tests on a release
build so they don't have to suffer with slower build times. The real
intention behind '--debug' was just the changing of CMAKE_BUILD_TYPE so
convert '--debug' into '--build-type' and unhook the LLVM tests from
that option.

We only save 29 targets (3783 -> 3752) by turning off LLVM_INCLUDE_TESTS
(tested with '--build-stage1-only') so there is no point in adding an
option to enable/disable that option.

LLVM_BUILD_TESTS is not needed to run tests so omit setting a value for
it.

Closes: ClangBuiltLinux#42
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>

build-llvm.py

@@ -90,6 +90,17 @@ def parse_parameters(root_folder):
 
                         """),
                         action="store_true")
+    parser.add_argument("--build-type",
+                        help=textwrap.dedent("""\
+                        By default, the script does a Release build; Debug may be useful for tracking down
+                        particularly nasty bugs.
+
+                        See https://llvm.org/docs/GettingStarted.html#compiling-the-llvm-suite-source-code for
+                        more information.
+
+                        """),
+                        type=str,
+                        default="Release")
     parser.add_argument("--clang-vendor",
                         help=textwrap.dedent("""\
                         Add this value to the clang version string (like "Apple clang version..." or
@@ -101,17 +112,6 @@ def parse_parameters(root_folder):
                         """),
                         type=str,
                         default="ClangBuiltLinux")
-    parser.add_argument("-d",
-                        "--debug",
-                        help=textwrap.dedent("""\
-                        By default, the script builds LLVM in the release configuration with all of
-                        the tests turned off and optimization at O2. This disables that optimization,
-                        builds the tests, and changes the configuration to debug. This can help with
-                        reporting problems to LLVM developers but will make compilation of both LLVM
-                        and the kernel go slower.
-
-                        """),
-                        action="store_true")
     parser.add_argument("-i",
                         "--incremental",
                         help=textwrap.dedent("""\
@@ -588,19 +588,17 @@ def stage_specific_cmake_defines(args, dirs, stage):
         defines['LLVM_INCLUDE_TESTS'] = 'OFF'
         defines['LLVM_INCLUDE_UTILS'] = 'OFF'
     else:
-        # If a debug build was requested
-        if args.debug:
-            defines['CMAKE_BUILD_TYPE'] = 'Debug'
-            defines['LLVM_BUILD_TESTS'] = 'ON'
-        # If a release build was requested
-        else:
-            defines['CMAKE_BUILD_TYPE'] = 'Release'
+        # https://llvm.org/docs/CMake.html#frequently-used-cmake-variables
+        defines['CMAKE_BUILD_TYPE'] = args.build_type.capitalize()
+
+        # We don't care about warnings if we are building a release build
+        if args.build_type.lower() == "release":
             defines['LLVM_ENABLE_WARNINGS'] = 'OFF'
-            defines['LLVM_INCLUDE_TESTS'] = 'OFF'
-            # Build with assertions enabled if requested (will slow down compilation
-            # so it is not on by default)
-            if args.assertions:
-                defines['LLVM_ENABLE_ASSERTIONS'] = 'ON'
+
+        # Build with assertions enabled if requested (will slow down compilation
+        # so it is not on by default)
+        if args.assertions:
+            defines['LLVM_ENABLE_ASSERTIONS'] = 'ON'
 
         # Where the toolchain should be installed
         defines['CMAKE_INSTALL_PREFIX'] = dirs.install_folder.as_posix()