diff --git a/.github/workflows/wasm.yml b/.github/workflows/wasm.yml
index d9a9c5cb7c..008a8678c5 100644
--- a/.github/workflows/wasm.yml
+++ b/.github/workflows/wasm.yml
@@ -9,6 +9,6 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: Build web
-        run: docker-compose up
+        run: docker-compose -f source/wasm/docker-compose.yml --project-directory . up
       - name: Run tests
         run: node test/wasm/test.js
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 63eeae8717..f9bfb4a303 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-cmake_minimum_required(VERSION 2.8.12)
+cmake_minimum_required(VERSION 3.17.2)
 if (POLICY CMP0048)
   cmake_policy(SET CMP0048 NEW)
 endif()
diff --git a/DEPS b/DEPS
index d6242d815f..b16d696431 100644
--- a/DEPS
+++ b/DEPS
@@ -4,7 +4,14 @@ vars = {
   'github': 'https://github.com',
 
   'effcee_revision': '35912e1b7778ec2ddcff7e7188177761539e59e0',
-  'googletest_revision': 'd9bb8412d60b993365abb53f00b6dad9b2c01b62',
+
+  # Pin to the last version of googletest that supports C++11.
+  # Anything later requires C++14
+  'googletest_revision': 'v1.12.0',
+
+  # Use protobufs before they gained the dependency on abseil
+  'protobuf_revision': 'v3.13.0.1',
+
   're2_revision': 'd2836d1b1c34c4e330a85a1006201db474bf2c8a',
   'spirv_headers_revision': '34d04647d384e0aed037e7a2662a655fc39841bb',
 }
@@ -16,6 +23,9 @@ deps = {
   'external/googletest':
       Var('github') + '/google/googletest.git@' + Var('googletest_revision'),
 
+  'external/protobuf':
+      Var('github') + '/protocolbuffers/protobuf.git@' + Var('protobuf_revision'),
+
   'external/re2':
       Var('github') + '/google/re2.git@' + Var('re2_revision'),
 
diff --git a/build_defs.bzl b/build_defs.bzl
index a94a425268..3a69de5c7b 100644
--- a/build_defs.bzl
+++ b/build_defs.bzl
@@ -4,7 +4,9 @@ COMMON_COPTS = [
     "-DSPIRV_CHECK_CONTEXT",
     "-DSPIRV_COLOR_TERMINAL",
 ] + select({
-    "@bazel_tools//src/conditions:windows": [],
+    # On Windows, assume MSVC.
+    # C++14 is the default in VisualStudio 2017.
+    "@platforms//os:windows": [],
     "//conditions:default": [
         "-DSPIRV_LINUX",
         "-DSPIRV_TIMER_ENABLED",
@@ -27,7 +29,7 @@ COMMON_COPTS = [
 
 TEST_COPTS = COMMON_COPTS + [
 ] + select({
-    "@bazel_tools//src/conditions:windows": [
+    "@platforms//os:windows": [
         # Disable C4503 "decorated name length exceeded" warning,
         # triggered by some heavily templated types.
         # We don't care much about that in test code.
diff --git a/kokoro/scripts/linux/build-docker.sh b/kokoro/scripts/linux/build-docker.sh
index 80043b8a4e..7d62ee3660 100755
--- a/kokoro/scripts/linux/build-docker.sh
+++ b/kokoro/scripts/linux/build-docker.sh
@@ -30,14 +30,6 @@ fi
 
 cd $ROOT_DIR
 
-function clone_if_missing() {
-  url=$1
-  dir=$2
-  if [[ ! -d "$dir" ]]; then
-    git clone ${@:3} "$url" "$dir"
-  fi
-}
-
 function clean_dir() {
   dir=$1
   if [[ -d "$dir" ]]; then
@@ -46,12 +38,8 @@ function clean_dir() {
   mkdir "$dir"
 }
 
-clone_if_missing https://github.com/KhronosGroup/SPIRV-Headers external/spirv-headers --depth=1
-clone_if_missing https://github.com/google/googletest          external/googletest
-pushd external/googletest; git reset --hard 1fb1bb23bb8418dc73a5a9a82bbed31dc610fec7; popd
-clone_if_missing https://github.com/google/effcee              external/effcee        --depth=1
-clone_if_missing https://github.com/google/re2                 external/re2           --depth=1
-clone_if_missing https://github.com/protocolbuffers/protobuf   external/protobuf      --branch v3.13.0.1
+# Get source for dependencies, as specified in the DEPS file
+/usr/bin/python3 utils/git-sync-deps --treeless
 
 if [ $TOOL = "cmake" ]; then
   using cmake-3.17.2
diff --git a/kokoro/scripts/macos/build.sh b/kokoro/scripts/macos/build.sh
index 3618e69053..1d346e7618 100644
--- a/kokoro/scripts/macos/build.sh
+++ b/kokoro/scripts/macos/build.sh
@@ -31,12 +31,7 @@ chmod +x ninja
 export PATH="$PWD:$PATH"
 
 cd $SRC
-git clone --depth=1 https://github.com/KhronosGroup/SPIRV-Headers external/spirv-headers
-git clone https://github.com/google/googletest          external/googletest
-cd external && cd googletest && git reset --hard 1fb1bb23bb8418dc73a5a9a82bbed31dc610fec7 && cd .. && cd ..
-git clone --depth=1 https://github.com/google/effcee              external/effcee
-git clone --depth=1 https://github.com/google/re2                 external/re2
-git clone --depth=1 --branch v3.13.0.1 https://github.com/protocolbuffers/protobuf external/protobuf
+python3 utils/git-sync-deps --treeless
 
 mkdir build && cd $SRC/build
 
diff --git a/kokoro/scripts/windows/build.bat b/kokoro/scripts/windows/build.bat
index d5ea6d0c20..89e1f01848 100644
--- a/kokoro/scripts/windows/build.bat
+++ b/kokoro/scripts/windows/build.bat
@@ -24,14 +24,6 @@ set VS_VERSION=%2
 :: Force usage of python 3.6
 set PATH=C:\python36;"C:\Program Files\cmake-3.23.1-windows-x86_64\bin";%PATH%
 
-cd %SRC%
-git clone --depth=1 https://github.com/KhronosGroup/SPIRV-Headers external/spirv-headers
-git clone https://github.com/google/googletest          external/googletest
-cd external && cd googletest && git reset --hard 1fb1bb23bb8418dc73a5a9a82bbed31dc610fec7 && cd .. && cd ..
-git clone --depth=1 https://github.com/google/effcee              external/effcee
-git clone --depth=1 https://github.com/google/re2                 external/re2
-git clone --depth=1 --branch v3.13.0.1 https://github.com/protocolbuffers/protobuf external/protobuf
-
 :: #########################################
 :: set up msvc build env
 :: #########################################
@@ -41,6 +33,8 @@ if %VS_VERSION% == 2017 (
 )
 
 cd %SRC%
+python utils/git-sync-deps --treeless
+
 mkdir build
 cd build
 
diff --git a/source/val/validate_cfg.cpp b/source/val/validate_cfg.cpp
index 24d2416927..9ba66f4224 100644
--- a/source/val/validate_cfg.cpp
+++ b/source/val/validate_cfg.cpp
@@ -560,7 +560,7 @@ spv_result_t StructuredSwitchChecks(ValidationState_t& _, Function* function,
           target_block->structurally_reachable() &&
           !header->structurally_dominates(*target_block)) {
         return _.diag(SPV_ERROR_INVALID_CFG, header->label())
-               << "Selection header " << _.getIdName(header->id())
+               << "Switch header " << _.getIdName(header->id())
                << " does not structurally dominate its case construct "
                << _.getIdName(target);
       }
diff --git a/docker-compose.yml b/source/wasm/docker-compose.yml
similarity index 84%
rename from docker-compose.yml
rename to source/wasm/docker-compose.yml
index fb6d114ffb..2340fdb02c 100644
--- a/docker-compose.yml
+++ b/source/wasm/docker-compose.yml
@@ -1,7 +1,7 @@
 version: "3"
 services:
   build:
-    image: emscripten/emsdk:2.0.2
+    image: emscripten/emsdk:3.1.28
     environment:
       GITHUB_RUN_NUMBER: ${GITHUB_RUN_NUMBER:-}
     working_dir: /app
diff --git a/test/val/val_cfg_test.cpp b/test/val/val_cfg_test.cpp
index 561e817e74..d876c4881d 100644
--- a/test/val/val_cfg_test.cpp
+++ b/test/val/val_cfg_test.cpp
@@ -2064,6 +2064,106 @@ OpFunctionEnd
   ASSERT_EQ(SPV_SUCCESS, ValidateInstructions());
 }
 
+TEST_F(ValidateCFG, OpSwitchTargetCannotBeOuterLoopMergeBlock) {
+  std::string text = R"(
+OpCapability Shader
+OpCapability Linkage
+OpMemoryModel Logical GLSL450
+
+%1 = OpTypeVoid
+%2 = OpTypeFunction %1
+%3 = OpTypeBool
+%4 = OpUndef %3
+%5 = OpTypeInt 32 0
+%6 = OpConstant %5 0
+
+%7 = OpFunction %1 None %2
+
+%8 = OpLabel
+OpBranch %9
+
+%9 = OpLabel
+OpLoopMerge %10 %11 None
+OpBranch %12
+
+%12 = OpLabel
+OpSelectionMerge %13 None
+OpSwitch %6 %13 0 %10 1 %14
+
+%14 = OpLabel
+OpBranch %13
+
+%13 = OpLabel
+OpBranch %11
+
+%11 = OpLabel
+OpBranch %9
+
+%10 = OpLabel
+OpReturn
+
+OpFunctionEnd
+)";
+
+  CompileSuccessfully(text);
+  ASSERT_EQ(SPV_ERROR_INVALID_CFG, ValidateInstructions());
+  EXPECT_THAT(
+      getDiagnosticString(),
+      HasSubstr(
+          "Switch header '12[%12]' does not structurally dominate its case construct '10[%10]'\n"
+          "  %12 = OpLabel"));
+}
+
+TEST_F(ValidateCFG, OpSwitchTargetCannotBeOuterLoopContinueBlock) {
+  std::string text = R"(
+OpCapability Shader
+OpCapability Linkage
+OpMemoryModel Logical GLSL450
+
+%1 = OpTypeVoid
+%2 = OpTypeFunction %1
+%3 = OpTypeBool
+%4 = OpUndef %3
+%5 = OpTypeInt 32 0
+%6 = OpConstant %5 0
+
+%7 = OpFunction %1 None %2
+
+%8 = OpLabel
+OpBranch %9
+
+%9 = OpLabel
+OpLoopMerge %10 %11 None
+OpBranch %12
+
+%12 = OpLabel
+OpSelectionMerge %13 None
+OpSwitch %6 %13 0 %11 1 %14
+
+%14 = OpLabel
+OpBranch %13
+
+%13 = OpLabel
+OpBranch %11
+
+%11 = OpLabel
+OpBranch %9
+
+%10 = OpLabel
+OpReturn
+
+OpFunctionEnd
+)";
+
+  CompileSuccessfully(text);
+  ASSERT_EQ(SPV_ERROR_INVALID_CFG, ValidateInstructions());
+  EXPECT_THAT(
+      getDiagnosticString(),
+      HasSubstr(
+          "Switch header '12[%12]' does not structurally dominate its case construct '11[%11]'\n"
+          "  %12 = OpLabel"));
+}
+
 TEST_F(ValidateCFG, WrongOperandList) {
   std::string text = R"(
 OpCapability Shader
diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index 86d0bc46a0..ad5f336fec 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -69,6 +69,22 @@ if (NOT ${SPIRV_SKIP_EXECUTABLES})
   endif(SPIRV_BUILD_FUZZER)
 
   if(ENABLE_SPIRV_TOOLS_INSTALL)
-    install(TARGETS ${SPIRV_INSTALL_TARGETS} DESTINATION ${CMAKE_INSTALL_BINDIR})
+    install(TARGETS ${SPIRV_INSTALL_TARGETS} EXPORT SPIRV-Tools-toolsTargets
+			RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+			LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+            ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR})
+    export(EXPORT SPIRV-Tools-toolsTargets FILE SPIRV-Tools-toolsTargets.cmake)
+
+    spvtools_config_package_dir(SPIRV-Tools-tools PACKAGE_DIR)
+    install(EXPORT SPIRV-Tools-toolsTargets FILE SPIRV-Tools-toolsTargets.cmake
+            DESTINATION ${PACKAGE_DIR})
+
+    file(WRITE ${CMAKE_BINARY_DIR}/SPIRV-Tools-toolsConfig.cmake
+      "include(CMakeFindDependencyMacro)\n"
+      "find_dependency(${SPIRV_TOOLS})\n"
+      "include(\${CMAKE_CURRENT_LIST_DIR}/SPIRV-Tools-toolsTargets.cmake)\n"
+      )
+
+    install(FILES ${CMAKE_BINARY_DIR}/SPIRV-Tools-toolsConfig.cmake DESTINATION ${PACKAGE_DIR})
   endif(ENABLE_SPIRV_TOOLS_INSTALL)
 endif()
diff --git a/utils/git-sync-deps b/utils/git-sync-deps
index 7a7e606ff1..6549afb1e6 100755
--- a/utils/git-sync-deps
+++ b/utils/git-sync-deps
@@ -28,10 +28,9 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 """Parse a DEPS file and git checkout all of the dependencies.
+"""
 
-Args:
-  An optional list of deps_os values.
-
+EXTRA_HELP = """
 Environment Variables:
   GIT_EXECUTABLE: path to "git" binary; if unset, will look for one of
   ['git', 'git.exe', 'git.bat'] in your default path.
@@ -52,6 +51,7 @@ Git Config:
 """
 
 
+import argparse
 import os
 import re
 import subprocess
@@ -59,12 +59,14 @@ import sys
 import threading
 from builtins import bytes
 
-
 def git_executable():
   """Find the git executable.
 
   Returns:
-      A string suitable for passing to subprocess functions, or None.
+      A triple:
+        A string suitable for passing to subprocess functions, or None.
+        The major version number
+        The minor version number
   """
   envgit = os.environ.get('GIT_EXECUTABLE')
   searchlist = ['git', 'git.exe', 'git.bat']
@@ -72,30 +74,36 @@ def git_executable():
     searchlist.insert(0, envgit)
   with open(os.devnull, 'w') as devnull:
     for git in searchlist:
+      major=None
+      minor=None
       try:
-        subprocess.call([git, '--version'], stdout=devnull)
+        version_info = subprocess.check_output([git, '--version']).decode('utf-8')
+        match = re.search("^git version (\d+)\.(\d+)",version_info)
+        print("Using {}".format(version_info))
+        if match:
+          major = int(match.group(1))
+          minor = int(match.group(2))
+        else:
+          continue
       except (OSError,):
         continue
-      return git
-  return None
+      return (git,major,minor)
+  return (None,0,0)
 
 
 DEFAULT_DEPS_PATH = os.path.normpath(
   os.path.join(os.path.dirname(__file__), os.pardir, 'DEPS'))
 
+def get_deps_os_str(deps_file):
+  parsed_deps = parse_file_to_dict(deps_file)
+  parts = []
+  if 'deps_os' in parsed_deps:
+    for deps_os in parsed_deps['deps_os']:
+      parts.append(' [{}]]'.format(deps_os))
+  return "\n".join(parts)
 
-def usage(deps_file_path = None):
-  sys.stderr.write(
-    'Usage: run to grab dependencies, with optional platform support:\n')
-  sys.stderr.write('  %s %s' % (sys.executable, __file__))
-  if deps_file_path:
-    parsed_deps = parse_file_to_dict(deps_file_path)
-    if 'deps_os' in parsed_deps:
-      for deps_os in parsed_deps['deps_os']:
-        sys.stderr.write(' [%s]' % deps_os)
-  sys.stderr.write('\n\n')
-  sys.stderr.write(__doc__)
-
+def looks_like_raw_commit(commit):
+  return re.match('^[a-f0-9]{40}$', commit) is not None
 
 def git_repository_sync_is_disabled(git, directory):
   try:
@@ -125,14 +133,14 @@ def is_git_toplevel(git, directory):
 
 def status(directory, checkoutable):
   def truncate(s, length):
-    return s if len(s) <= length else s[:(length - 3)] + '...'
+    return s if len(s) <= length else '...' + s[-(length - 3):]
   dlen = 36
   directory = truncate(directory, dlen)
   checkoutable = truncate(checkoutable, 40)
   sys.stdout.write('%-*s @ %s\n' % (dlen, directory, checkoutable))
 
 
-def git_checkout_to_directory(git, repo, checkoutable, directory, verbose):
+def git_checkout_to_directory(git, repo, checkoutable, directory, verbose, treeless):
   """Checkout (and clone if needed) a Git repository.
 
   Args:
@@ -147,13 +155,22 @@ def git_checkout_to_directory(git, repo, checkoutable, directory, verbose):
     directory (string) the path into which the repository
               should be checked out.
 
-    verbose (boolean)
+    verbose (boolean): emit status info to stdout
+
+    treeless (boolean): when true, clone without any trees.
 
   Raises an exception if any calls to git fail.
   """
   if not os.path.isdir(directory):
+    # Use blobless or treeless checkouts for faster downloads.
+    # This defers some work to checkout time.
+    # https://github.blog/2020-12-21-get-up-to-speed-with-partial-clone-and-shallow-clone/
+    filter = ['--filter=tree:0'] if treeless else ['--filter=blob:none']
+    # If the thing to check out looks like a tag (and not like a commit),
+    # then limit the checkout to that branch.
+    branch = [] if looks_like_raw_commit(checkoutable) else ['--branch={}'.format(checkoutable)]
     subprocess.check_call(
-      [git, 'clone', '--quiet', repo, directory])
+        [git, 'clone', '--quiet', '--single-branch'] + filter + branch + [repo, directory])
 
   if not is_git_toplevel(git, directory):
     # if the directory exists, but isn't a git repo, you will modify
@@ -200,7 +217,7 @@ def parse_file_to_dict(path):
   return dictionary
 
 
-def git_sync_deps(deps_file_path, command_line_os_requests, verbose):
+def git_sync_deps(deps_file_path, command_line_os_requests, verbose, treeless):
   """Grab dependencies, with optional platform support.
 
   Args:
@@ -210,11 +227,20 @@ def git_sync_deps(deps_file_path, command_line_os_requests, verbose):
         List of strings that should each be a key in the deps_os
         dictionary in the DEPS file.
 
+    verbose (boolean): emit status info to stdout
+
+    treeless (boolean): when true, clone as treeless instead of blobless
+
   Raises git Exceptions.
   """
-  git = git_executable()
+  (git,git_major,git_minor) = git_executable()
   assert git
 
+  # --filter=tree:0 is available in git 2.20 and later
+  if (git_major,git_minor) < (2,20):
+    print("disabling --treeless: git is older than v2.20")
+    treeless = False
+
   deps_file_directory = os.path.dirname(deps_file_path)
   deps_file = parse_file_to_dict(deps_file_path)
   dependencies = deps_file['deps'].copy()
@@ -241,7 +267,7 @@ def git_sync_deps(deps_file_path, command_line_os_requests, verbose):
     relative_directory = os.path.join(deps_file_directory, directory)
 
     list_of_arg_lists.append(
-      (git, repo, checkoutable, relative_directory, verbose))
+      (git, repo, checkoutable, relative_directory, verbose, treeless))
 
   multithread(git_checkout_to_directory, list_of_arg_lists)
 
@@ -264,17 +290,47 @@ def multithread(function, list_of_arg_lists):
 
 
 def main(argv):
-  deps_file_path = os.environ.get('GIT_SYNC_DEPS_PATH', DEFAULT_DEPS_PATH)
-  verbose = not bool(os.environ.get('GIT_SYNC_DEPS_QUIET', False))
-
-  if '--help' in argv or '-h' in argv:
-    usage(deps_file_path)
-    return 1
-
-  git_sync_deps(deps_file_path, argv, verbose)
-  # subprocess.check_call(
-  #     [sys.executable,
-  #      os.path.join(os.path.dirname(deps_file_path), 'bin', 'fetch-gn')])
+  argparser = argparse.ArgumentParser(
+          prog = "git-sync-deps",
+          description = "Checkout git-based dependencies as specified by the DEPS file",
+          add_help=False # Because we want to print deps_os with -h option
+          )
+  argparser.add_argument("--help", "-h",
+                         action='store_true',
+                         help="show this help message and exit")
+  argparser.add_argument("--deps",
+                         default = os.environ.get('GIT_SYNC_DEPS_PATH', DEFAULT_DEPS_PATH),
+                         help="location of the the DEPS file")
+  argparser.add_argument("--verbose",
+                         default=not bool(os.environ.get('GIT_SYNC_DEPS_QUIET', False)),
+                         action='store_true',
+                         help="be verbose: print status messages")
+  argparser.add_argument("--treeless",
+                         default=False,
+                         action='store_true',
+                         help="""
+    Clone repos without trees (--filter=tree:0).
+    This is the fastest option for a build machine,
+    when you only need a single commit.
+    Defers getting objects until checking out a commit.
+
+    The default is to clone with trees but without blobs.
+
+    Only takes effect if using git 2.20 or later.
+
+    See https://github.blog/2020-12-21-get-up-to-speed-with-partial-clone-and-shallow-clone/
+                              """)
+  argparser.add_argument("os_requests",nargs="*",
+                         help="OS requests, as keys in the deps_os dictionariy in the DEPS file")
+
+  args = argparser.parse_args()
+  if args.help:
+    print(argparser.format_help())
+    print(EXTRA_HELP)
+    print(get_deps_os_str(args.deps))
+    return 0
+
+  git_sync_deps(args.deps, args.os_requests, args.verbose, args.treeless)
   return 0