update to clang 10

Kind of a big rewrite to adapt to the new repository structure.

Change-Id: I7b437aaa6bdf684c4486fe91fe94984107b7f6f9
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/279072
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>

infra/bots/assets/clang_linux/VERSION

@@ -1 +1 @@
-19
+20

infra/bots/assets/clang_linux/create.py

@@ -14,39 +14,24 @@
 import subprocess
 import tempfile
 
-REPO = "https://llvm.googlesource.com/"
-BRANCH = "release_90"
+BRANCH = "release/10.x"
 
 def create_asset(target_dir):
   # CMake will sometimes barf if we pass it a relative path.
   target_dir = os.path.abspath(target_dir)
 
   # Build Clang, lld, compiler-rt (sanitizer support) and libc++.
   os.chdir(tempfile.mkdtemp())
-  subprocess.check_call(["git", "clone", "--depth", "1", "-b",
-                         BRANCH, REPO + "llvm"])
-  os.chdir("llvm/tools")
-  subprocess.check_call(["git", "clone", "--depth", "1", "-b",
-                         BRANCH, REPO + "clang"])
-  subprocess.check_call(["git", "clone", "--depth", "1", "-b",
-                         BRANCH, REPO + "lld"])
-  os.chdir("clang/tools")
-  subprocess.check_call(["git", "clone", "--depth", "1", "-b",
-                         BRANCH, REPO + "clang-tools-extra", "extra"])
-
-  os.chdir("../../../projects")
-  subprocess.check_call(["git", "clone", "--depth", "1", "-b",
-                         BRANCH, REPO + "compiler-rt"])
-  subprocess.check_call(["git", "clone", "--depth", "1", "-b",
-                         BRANCH, REPO + "libcxx"])
-  subprocess.check_call(["git", "clone", "--depth", "1", "-b",
-                         BRANCH, REPO + "libcxxabi"])
-  os.chdir("..")
+  subprocess.check_call(["git", "clone", "--depth", "1", "-b", BRANCH,
+                         "https://llvm.googlesource.com/llvm-project"])
+  os.chdir("llvm-project")
   os.mkdir("out")
   os.chdir("out")
-  subprocess.check_call(["cmake", "..", "-G", "Ninja",
+  subprocess.check_call(["cmake", "../llvm", "-G", "Ninja",
                          "-DCMAKE_BUILD_TYPE=MinSizeRel",
                          "-DCMAKE_INSTALL_PREFIX=" + target_dir,
+                         "-DLLVM_ENABLE_PROJECTS=clang;clang-tools-extra;" +
+                             "compiler-rt;libcxx;libcxxabi;lld",
                          "-DLLVM_INSTALL_TOOLCHAIN_ONLY=ON",
                          "-DLLVM_ENABLE_TERMINFO=OFF"])
   subprocess.check_call(["ninja", "install"])
@@ -64,10 +49,11 @@ def create_asset(target_dir):
     os.mkdir("../{}_out".format(short))
     os.chdir("../{}_out".format(short))
     subprocess.check_call(
-        ["cmake", "..", "-G", "Ninja",
+        ["cmake", "../llvm", "-G", "Ninja",
          "-DCMAKE_BUILD_TYPE=MinSizeRel",
          "-DCMAKE_C_COMPILER="   + target_dir + "/bin/clang",
          "-DCMAKE_CXX_COMPILER=" + target_dir + "/bin/clang++",
+         "-DLLVM_ENABLE_PROJECTS=libcxx;libcxxabi",
          "-DLLVM_USE_SANITIZER={}".format(full)])
     subprocess.check_call(["ninja", "cxx"])
     subprocess.check_call(["cp", "-r", "lib",  target_dir + "/" + short])