diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 8c3afd805fe23..b53c49e788445 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -19,7 +19,7 @@ jobs:
       - name: Free disk space
         run: |
           df -h
-          sudo apt-get purge libgcc-9-dev gcc-9 libstdc++-9-dev
+          sudo apt-get purge libgcc-9-dev gcc-9 libstdc++-9-dev gcc-10 libgcc-10-dev
           sudo swapoff -a
           sudo rm -f /swapfile
           sudo rm -rf /opt/hostedtoolcache
@@ -69,6 +69,7 @@ jobs:
         run: |
           df -h
           sudo swapoff -a
+          sudo apt-get purge gcc-10 libgcc-10-dev
           sudo rm -f /swapfile
           sudo rm -rf /opt/hostedtoolcache
           sudo rm -rf /usr/share/dotnet
diff --git a/utils/update_checkout/update-checkout-config.json b/utils/update_checkout/update-checkout-config.json
index f51f36a54cac4..0b68d7fbd5bc9 100644
--- a/utils/update_checkout/update-checkout-config.json
+++ b/utils/update_checkout/update-checkout-config.json
@@ -8,6 +8,10 @@
             "remote": { "id": "apple/swift-cmark" } },
         "llbuild": {
             "remote": { "id": "apple/swift-llbuild" } },
+        "swift-argument-parser": {
+            "remote": { "id": "apple/swift-argument-parser" } },
+        "swift-driver": {
+            "remote": { "id": "apple/swift-driver" } },
         "swift-tools-support-core": {
             "remote": { "id": "apple/swift-tools-support-core" } },
         "swiftpm": {
@@ -31,20 +35,17 @@
         "icu": {
             "remote": { "id": "unicode-org/icu" }
         },
+        "yams": {
+            "remote": { "id": "jpsim/Yams" }
+        },
         "cmake": {
             "remote": { "id": "KitWare/CMake" },
             "platforms": [ "Linux" ]
         },
-        "pythonkit": {
-            "remote": { "id": "pvieito/PythonKit" }
-        },
-        "tensorflow-swift-apis": {
-            "remote": { "id": "tensorflow/swift-apis" }
-        },
        "indexstore-db": {
             "remote": { "id": "apple/indexstore-db" } },
         "sourcekit-lsp": {
-            "remote": { "id": "apple/sourcekit-lsp" } },
+            "remote": { "id": "swiftwasm/sourcekit-lsp" } },
         "swift-format": {
             "remote": { "id": "apple/swift-format" } },
         "llvm-project": {
@@ -57,23 +58,24 @@
             "repos": {
                 "llvm-project": "swiftwasm",
                 "swift": "swiftwasm",
-                "cmark": "master",
-                "llbuild": "master",
-                "swift-tools-support-core": "master",
+                "cmark": "main",
+                "llbuild": "main",
+                "swift-tools-support-core": "main",
                 "swiftpm": "swiftwasm",
-                "swift-syntax": "master",
-                "swift-stress-tester": "master",
-                "swift-corelibs-xctest": "master",
-                "swift-corelibs-foundation": "master",
-                "swift-corelibs-libdispatch": "master",
-                "swift-integration-tests": "master",
-                "swift-xcode-playground-support": "master",
+                "swift-argument-parser": "0.3.0",
+                "swift-syntax": "main",
+                "swift-stress-tester": "main",
+                "swift-corelibs-xctest": "main",
+                "swift-corelibs-foundation": "main",
+                "swift-corelibs-libdispatch": "main",
+                "swift-integration-tests": "main",
+                "swift-xcode-playground-support": "main",
                 "ninja": "release",
                 "icu": "release-65-1",
                 "cmake": "v3.16.5",               
-                "indexstore-db": "master",
-                "sourcekit-lsp": "master",
-                "swift-format": "master"
+                "indexstore-db": "main",
+                "sourcekit-lsp": "main",
+                "swift-format": "main"
             }
         },
         "wasm/5.3": {
@@ -85,6 +87,7 @@
                 "llbuild": "release/5.3",
                 "swift-tools-support-core": "release/5.3",
                 "swiftpm": "swiftwasm-release/5.3",
+                "swift-argument-parser": "0.3.0",
                 "swift-syntax": "release/5.3",
                 "swift-stress-tester": "release/5.3",
                 "swift-corelibs-xctest": "swiftwasm-release/5.3",
@@ -96,62 +99,65 @@
                 "icu": "release-65-1",
                 "cmake": "v3.16.5",               
                 "indexstore-db": "release/5.3",
-                "sourcekit-lsp": "release/5.3",
+                "sourcekit-lsp": "swiftwasm-release/5.3",
                 "swift-format": "main"
             }
         },
-        "master": {
-            "aliases": ["master", "swift/master"],
+       "main": {
+            "aliases": ["master", "swift/main", "main"],
             "repos": {
-                "llvm-project": "swift/master",
-                "swift": "master",
-                "cmark": "master",
-                "llbuild": "master",
-                "swift-tools-support-core": "master",
-                "swiftpm": "master",
-                "swift-syntax": "master",
-                "swift-stress-tester": "master",
-                "swift-corelibs-xctest": "master",
-                "swift-corelibs-foundation": "master",
-                "swift-corelibs-libdispatch": "master",
-                "swift-integration-tests": "master",
-                "swift-xcode-playground-support": "master",
+                "llvm-project": "swift/main",
+                "swift": "main",
+                "cmark": "main",
+                "llbuild": "main",
+                "swift-tools-support-core": "main",
+                "swiftpm": "main",
+                "swift-argument-parser": "0.3.0",
+                "swift-driver": "main",
+                "swift-syntax": "main",
+                "swift-stress-tester": "main",
+                "swift-corelibs-xctest": "main",
+                "swift-corelibs-foundation": "main",
+                "swift-corelibs-libdispatch": "main",
+                "swift-integration-tests": "main",
+                "swift-xcode-playground-support": "main",
                 "ninja": "release",
                 "icu": "release-65-1",
+                "yams": "3.0.1",
                 "cmake": "v3.16.5",
-                "indexstore-db": "master",
-                "sourcekit-lsp": "master",
-                "swift-format": "master",
-                "pythonkit": "master",
-                "tensorflow-swift-apis": "master"
+                "indexstore-db": "main",
+                "sourcekit-lsp": "main",
+                "swift-format": "main"
             }
         },
         "next" : {
             "aliases": ["next", "master-next",
+                        "swift/next",
                         "stable-next", "upstream",
                         "next-upstream", "upstream-with-swift"],
             "repos": {
-                "llvm-project": "swift/master-next",
-                "swift": "master-next",
-                "cmark": "master",
-                "llbuild": "master",
-                "swift-tools-support-core": "master",
-                "swiftpm": "master",
-                "swift-syntax": "master",
-                "swift-stress-tester": "master",
-                "swift-corelibs-xctest": "master",
-                "swift-corelibs-foundation": "master",
-                "swift-corelibs-libdispatch": "master",
-                "swift-integration-tests": "master",
-                "swift-xcode-playground-support": "master",
+                "llvm-project": "swift/next",
+                "swift": "next",
+                "cmark": "main",
+                "llbuild": "main",
+                "swift-tools-support-core": "main",
+                "swiftpm": "main",
+                "swift-argument-parser": "0.3.0",
+                "swift-driver": "main",
+                "swift-syntax": "main",
+                "swift-stress-tester": "main",
+                "swift-corelibs-xctest": "main",
+                "swift-corelibs-foundation": "main",
+                "swift-corelibs-libdispatch": "main",
+                "swift-integration-tests": "main",
+                "swift-xcode-playground-support": "main",
                 "ninja": "release",
                 "icu": "release-65-1",
+                "yams": "3.0.1",
                 "cmake": "v3.16.5",
-                "indexstore-db": "master",
-                "sourcekit-lsp": "master",
-                "swift-format": "master",
-                "pythonkit": "master",
-                "tensorflow-swift-apis": "master"
+                "indexstore-db": "main",
+                "sourcekit-lsp": "main",
+                "swift-format": "main"
             }
         },
        "swift-3.0-branch" : {
@@ -161,17 +167,17 @@
                 "cmark": "swift-3.0-branch",
                 "llbuild": "swift-3.0-branch",
                 "swiftpm": "swift-3.0-branch",
-                "swift-syntax": "master",
-                "swift-stress-tester": "master",
+                "swift-syntax": "main",
+                "swift-stress-tester": "main",
                 "swift-corelibs-xctest": "swift-3.0-branch",
                 "swift-corelibs-foundation": "swift-3.0-branch",
                 "swift-corelibs-libdispatch": "swift-3.0-branch",
                 "swift-integration-tests": "swift-3.0-branch",
                 "swift-xcode-playground-support": "swift-3.0-branch",
                 "ninja": "release",
-                "indexstore-db": "master",
-                "sourcekit-lsp": "master",
-                "swift-format": "master"
+                "indexstore-db": "main",
+                "sourcekit-lsp": "main",
+                "swift-format": "main"
             }
         },
         "swift-3.1-branch" : {
@@ -182,17 +188,17 @@
                 "cmark": "swift-3.1-branch",
                 "llbuild": "swift-3.1-branch",
                 "swiftpm": "swift-3.1-branch",
-                "swift-syntax": "master",
-                "swift-stress-tester": "master",
+                "swift-syntax": "main",
+                "swift-stress-tester": "main",
                 "swift-corelibs-xctest": "swift-3.1-branch",
                 "swift-corelibs-foundation": "swift-3.1-branch",
                 "swift-corelibs-libdispatch": "swift-3.1-branch",
                 "swift-integration-tests": "swift-3.1-branch",
                 "swift-xcode-playground-support": "swift-3.1-branch",
                 "ninja": "release",
-                "indexstore-db": "master",
-                "sourcekit-lsp": "master",
-                "swift-format": "master"
+                "indexstore-db": "main",
+                "sourcekit-lsp": "main",
+                "swift-format": "main"
             }
         },
         "swift-4.0-branch" : {
@@ -203,17 +209,17 @@
                 "cmark": "swift-4.0-branch",
                 "llbuild": "swift-4.0-branch",
                 "swiftpm": "swift-4.0-branch",
-                "swift-syntax": "master",
-                "swift-stress-tester": "master",
+                "swift-syntax": "main",
+                "swift-stress-tester": "main",
                 "swift-corelibs-xctest": "swift-4.0-branch",
                 "swift-corelibs-foundation": "swift-4.0-branch",
                 "swift-corelibs-libdispatch": "swift-4.0-branch",
                 "swift-integration-tests": "swift-4.0-branch",
                 "swift-xcode-playground-support": "swift-4.0-branch",
                 "ninja": "release",
-                "indexstore-db": "master",
-                "sourcekit-lsp": "master",
-                "swift-format": "master"
+                "indexstore-db": "main",
+                "sourcekit-lsp": "main",
+                "swift-format": "main"
             }
         },
         "swift-4.1-branch" : {
@@ -224,17 +230,17 @@
                 "cmark": "swift-4.1-branch",
                 "llbuild": "swift-4.1-branch",
                 "swiftpm": "swift-4.1-branch",
-                "swift-syntax": "master",
-                "swift-stress-tester": "master",
+                "swift-syntax": "main",
+                "swift-stress-tester": "main",
                 "swift-corelibs-xctest": "swift-4.1-branch",
                 "swift-corelibs-foundation": "swift-4.1-branch",
                 "swift-corelibs-libdispatch": "swift-4.1-branch",
                 "swift-integration-tests": "swift-4.1-branch",
                 "swift-xcode-playground-support": "swift-4.1-branch",
                 "ninja": "release",
-                "indexstore-db": "master",
-                "sourcekit-lsp": "master",
-                "swift-format": "master"
+                "indexstore-db": "main",
+                "sourcekit-lsp": "main",
+                "swift-format": "main"
             }
         },
         "swift-4.2-branch" : {
@@ -246,16 +252,16 @@
                 "llbuild": "swift-4.2-branch",
                 "swiftpm": "swift-4.2-branch",
                 "swift-syntax": "swift-4.2-branch",
-                "swift-stress-tester": "master",
+                "swift-stress-tester": "main",
                 "swift-corelibs-xctest": "swift-4.2-branch",
                 "swift-corelibs-foundation": "swift-4.2-branch",
                 "swift-corelibs-libdispatch": "swift-4.2-branch",
                 "swift-integration-tests": "swift-4.2-branch",
                 "swift-xcode-playground-support": "swift-4.2-branch",
                 "ninja": "release",
-                "indexstore-db": "master",
-                "sourcekit-lsp": "master",
-                "swift-format": "master"
+                "indexstore-db": "main",
+                "sourcekit-lsp": "main",
+                "swift-format": "main"
             }
         },
         "swift-5.0-branch" : {
@@ -275,9 +281,9 @@
                 "swift-xcode-playground-support": "swift-5.0-branch",
                 "ninja": "release",
                 "icu": "release-61-1",
-                "indexstore-db": "master",
-                "sourcekit-lsp": "master",
-                "swift-format": "master"
+                "indexstore-db": "main",
+                "sourcekit-lsp": "main",
+                "swift-format": "main"
             }
         },
        "swift-5.1-branch" : {
@@ -299,7 +305,7 @@
                 "icu": "release-61-1",
                 "indexstore-db": "swift-5.1-branch",
                 "sourcekit-lsp": "swift-5.1-branch",
-                "swift-format": "master"
+                "swift-format": "main"
             }
         },
        "swift-5.2-branch": {
@@ -323,7 +329,7 @@
                 "cmake": "v3.15.1",
                 "indexstore-db": "swift-5.2-branch",
                 "sourcekit-lsp": "swift-5.2-branch",
-                "swift-format": "master"
+                "swift-format": "main"
             }
         },
        "release/5.3": {
@@ -347,33 +353,7 @@
                 "cmake": "v3.16.5",
                 "indexstore-db": "release/5.3",
                 "sourcekit-lsp": "release/5.3",
-                "swift-format": "master",
-                "pythonkit": "master",
-                "tensorflow-swift-apis": "master"
-            }
-        },
-       "master-rebranch": {
-            "aliases": ["master-rebranch", "swift/master-rebranch"],
-            "repos": {
-                "llvm-project": "swift/master-rebranch",
-                "swift": "master-rebranch",
-                "cmark": "master",
-                "llbuild": "master",
-                "swift-tools-support-core": "master",
-                "swiftpm": "master",
-                "swift-syntax": "master",
-                "swift-stress-tester": "master",
-                "swift-corelibs-xctest": "master",
-                "swift-corelibs-foundation": "master",
-                "swift-corelibs-libdispatch": "master",
-                "swift-integration-tests": "master",
-                "swift-xcode-playground-support": "master",
-                "ninja": "release",
-                "icu": "release-65-1",
-                "cmake": "v3.16.5",
-                "indexstore-db": "master",
-                "sourcekit-lsp": "master",
-                "swift-format": "master"
+                "swift-format": "main"
             }
         }
     }
diff --git a/utils/webassembly/linux/install-dependencies.sh b/utils/webassembly/linux/install-dependencies.sh
index 0f70730ecbb6b..7c77cb07e47d4 100755
--- a/utils/webassembly/linux/install-dependencies.sh
+++ b/utils/webassembly/linux/install-dependencies.sh
@@ -6,12 +6,14 @@ sudo apt update
 
 if [ $(grep RELEASE /etc/lsb-release) == "DISTRIB_RELEASE=18.04" ]; then
   sudo apt install -y \
-    git ninja-build clang python python-six \
+    git ninja-build clang-10 python python-six \
     uuid-dev libicu-dev icu-devtools libbsd-dev \
     libedit-dev libxml2-dev libsqlite3-dev swig \
     libpython-dev libncurses5-dev pkg-config \
     libblocksruntime-dev libcurl4-openssl-dev \
-    systemtap-sdt-dev tzdata rsync wget llvm zip unzip
+    systemtap-sdt-dev tzdata rsync wget llvm-10 zip unzip
+  sudo ln -s -f /usr/bin/clang-10 /usr/bin/clang
+  sudo ln -s -f /usr/bin/clang++-10 /usr/bin/clang++
 elif [ $(grep RELEASE /etc/lsb-release) == "DISTRIB_RELEASE=20.04" ]; then
   sudo apt install -y \
     git ninja-build clang python python-six \