diff --git a/cmake/caches/Windows-aarch64.cmake b/cmake/caches/Windows-aarch64.cmake
index 6dd9a786b9065..fef9e80fe1672 100644
--- a/cmake/caches/Windows-aarch64.cmake
+++ b/cmake/caches/Windows-aarch64.cmake
@@ -26,9 +26,24 @@ set(LLVM_DEFAULT_TARGET_TRIPLE aarch64-unknown-windows-msvc CACHE STRING "")
 set(LLVM_APPEND_VC_REV NO CACHE BOOL "")
 set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR YES CACHE BOOL "")
 set(LLVM_ENABLE_PYTHON YES CACHE BOOL "")
-set(LLVM_RUNTIME_TARGETS
+
+set(default_targets
+      x86_64-unknown-windows-msvc
       aarch64-unknown-windows-msvc
-    CACHE STRING "")
+      i686-unknown-windows-msvc)
+set(LLVM_RUNTIME_TARGETS ${default_targets} CACHE STRING "")
+
+# Build the android builtins if NDK path is provided.
+if(NOT "$ENV{NDKPATH}" STREQUAL "")
+  list(APPEND default_targets
+       aarch64-unknown-linux-android
+       x86_64-unknown-linux-android
+       i686-unknown-linux-android
+       armv7-unknown-linux-androideabi)
+endif()
+
+set(LLVM_BUILTIN_TARGETS ${default_targets} CACHE STRING "")
+
 foreach(target ${LLVM_RUNTIME_TARGETS})
   set(RUNTIMES_${target}_LLVM_ENABLE_RUNTIMES
         compiler-rt
@@ -36,11 +51,40 @@ foreach(target ${LLVM_RUNTIME_TARGETS})
   set(RUNTIMES_${target}_CMAKE_MT mt CACHE STRING "")
   set(RUNTIMES_${target}_CMAKE_SYSTEM_NAME Windows CACHE STRING "")
   set(RUNTIMES_${target}_CMAKE_BUILD_TYPE Release CACHE STRING "")
+  set(RUNTIMES_${target}_COMPILER_RT_BUILD_BUILTINS YES CACHE BOOL "")
   set(RUNTIMES_${target}_COMPILER_RT_BUILD_CRT NO CACHE BOOL "")
   set(RUNTIMES_${target}_COMPILER_RT_BUILD_LIBFUZZER NO CACHE BOOL "")
+  set(RUNTIMES_${target}_COMPILER_RT_BUILD_ORC NO CACHE BOOL "")
   set(RUNTIMES_${target}_COMPILER_RT_BUILD_PROFILE YES CACHE BOOL "")
-  set(RUNTIMES_${target}_COMPILER_RT_BUILD_SANITIZERS NO CACHE BOOL "")
   set(RUNTIMES_${target}_COMPILER_RT_BUILD_XRAY NO CACHE BOOL "")
+  # Sanitizers will be configured, but not built. We have separate build
+  # steps for that, because we need a different shell for each target.
+  set(RUNTIMES_${target}_COMPILER_RT_BUILD_SANITIZERS NO CACHE BOOL "")
+endforeach()
+
+foreach(target ${LLVM_BUILTIN_TARGETS})
+  set(BUILTINS_${target}_CMAKE_MT mt CACHE STRING "")
+  if(${target} MATCHES windows-msvc)
+    set(BUILTINS_${target}_CMAKE_SYSTEM_NAME Windows CACHE STRING "")
+  elseif(${target} MATCHES linux-android)
+    # Use a single 'linux' directory and arch-based lib names on Android.
+    set(BUILTINS_${target}_LLVM_ENABLE_PER_TARGET_RUNTIME_DIR NO CACHE BOOL "")
+    set(BUILTINS_${target}_CMAKE_SYSTEM_NAME Android CACHE STRING "")
+    if(${target} MATCHES aarch64)
+      set(BUILTINS_${target}_CMAKE_ANDROID_ARCH_ABI arm64-v8a CACHE STRING "")
+    elseif(${target} MATCHES armv7)
+      set(BUILTINS_${target}_CMAKE_ANDROID_ARCH_ABI armeabi-v7a CACHE STRING "")
+    elseif(${target} MATCHES i686)
+      set(BUILTINS_${target}_CMAKE_ANDROID_ARCH_ABI x86 CACHE STRING "")
+    else()
+      set(BUILTINS_${target}_CMAKE_ANDROID_ARCH_ABI x86_64 CACHE STRING "")
+    endif()
+    set(BUILTINS_${target}_CMAKE_ANDROID_NDK $ENV{NDKPATH} CACHE PATH "")
+    set(BUILTINS_${target}_CMAKE_ANDROID_API 21 CACHE STRING "")
+    set(BUILTINS_${target}_CMAKE_C_COMPILER_TARGET "${target}21" CACHE STRING "")
+    set(BUILTINS_${target}_CMAKE_CXX_COMPILER_TARGET "${target}21" CACHE STRING "")
+  endif()
+  set(BUILTINS_${target}_CMAKE_BUILD_TYPE Release CACHE STRING "")
 endforeach()
 
 set(LLVM_TARGETS_TO_BUILD AArch64 ARM WebAssembly X86 CACHE STRING "")
@@ -165,6 +209,7 @@ set(LLVM_DISTRIBUTION_COMPONENTS
       libclang
       libclang-headers
       LTO
+      builtins
       runtimes
       ${LLVM_TOOLCHAIN_TOOLS}
       ${CLANG_TOOLS}
diff --git a/cmake/caches/Windows-x86_64.cmake b/cmake/caches/Windows-x86_64.cmake
index 0f146d3f4e43a..7878887b3f824 100644
--- a/cmake/caches/Windows-x86_64.cmake
+++ b/cmake/caches/Windows-x86_64.cmake
@@ -27,24 +27,22 @@ set(LLVM_APPEND_VC_REV NO CACHE BOOL "")
 set(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR YES CACHE BOOL "")
 set(LLVM_ENABLE_PYTHON YES CACHE BOOL "")
 
-set(DEFAULT_BUILTIN_TARGETS
+set(default_targets
       x86_64-unknown-windows-msvc
-      aarch64-unknown-windows-msvc)
+      aarch64-unknown-windows-msvc
+      i686-unknown-windows-msvc)
+set(LLVM_RUNTIME_TARGETS ${default_targets} CACHE STRING "")
+
 # Build the android builtins if NDK path is provided.
 if(NOT "$ENV{NDKPATH}" STREQUAL "")
-  list(APPEND DEFAULT_BUILTIN_TARGETS
+  list(APPEND default_targets
        aarch64-unknown-linux-android
-       x86_64-unknown-linux-android)
+       x86_64-unknown-linux-android
+       i686-unknown-linux-android
+       armv7-unknown-linux-androideabi)
 endif()
 
-# The builtin targets are used to build the compiler-rt builtins.
-set(LLVM_BUILTIN_TARGETS ${DEFAULT_BUILTIN_TARGETS} CACHE STRING "")
-
-# The runtime targets are used to build the compiler-rt profile library.
-set(LLVM_RUNTIME_TARGETS
-      x86_64-unknown-windows-msvc
-      aarch64-unknown-windows-msvc
-    CACHE STRING "")
+set(LLVM_BUILTIN_TARGETS ${default_targets} CACHE STRING "")
 
 foreach(target ${LLVM_RUNTIME_TARGETS})
   set(RUNTIMES_${target}_LLVM_ENABLE_RUNTIMES
@@ -53,13 +51,15 @@ foreach(target ${LLVM_RUNTIME_TARGETS})
   set(RUNTIMES_${target}_CMAKE_MT mt CACHE STRING "")
   set(RUNTIMES_${target}_CMAKE_SYSTEM_NAME Windows CACHE STRING "")
   set(RUNTIMES_${target}_CMAKE_BUILD_TYPE Release CACHE STRING "")
-  set(RUNTIMES_${target}_COMPILER_RT_BUILD_BUILTINS NO CACHE BOOL "")
+  set(RUNTIMES_${target}_COMPILER_RT_BUILD_BUILTINS YES CACHE BOOL "")
   set(RUNTIMES_${target}_COMPILER_RT_BUILD_CRT NO CACHE BOOL "")
   set(RUNTIMES_${target}_COMPILER_RT_BUILD_LIBFUZZER NO CACHE BOOL "")
   set(RUNTIMES_${target}_COMPILER_RT_BUILD_ORC NO CACHE BOOL "")
   set(RUNTIMES_${target}_COMPILER_RT_BUILD_PROFILE YES CACHE BOOL "")
-  set(RUNTIMES_${target}_COMPILER_RT_BUILD_SANITIZERS NO CACHE BOOL "")
   set(RUNTIMES_${target}_COMPILER_RT_BUILD_XRAY NO CACHE BOOL "")
+  # Sanitizers will be configured, but not built. We have separate build
+  # steps for that, because we need a different shell for each target.
+  set(RUNTIMES_${target}_COMPILER_RT_BUILD_SANITIZERS NO CACHE BOOL "")
 endforeach()
 
 foreach(target ${LLVM_BUILTIN_TARGETS})
@@ -72,6 +72,10 @@ foreach(target ${LLVM_BUILTIN_TARGETS})
     set(BUILTINS_${target}_CMAKE_SYSTEM_NAME Android CACHE STRING "")
     if(${target} MATCHES aarch64)
       set(BUILTINS_${target}_CMAKE_ANDROID_ARCH_ABI arm64-v8a CACHE STRING "")
+    elseif(${target} MATCHES armv7)
+      set(BUILTINS_${target}_CMAKE_ANDROID_ARCH_ABI armeabi-v7a CACHE STRING "")
+    elseif(${target} MATCHES i686)
+      set(BUILTINS_${target}_CMAKE_ANDROID_ARCH_ABI x86 CACHE STRING "")
     else()
       set(BUILTINS_${target}_CMAKE_ANDROID_ARCH_ABI x86_64 CACHE STRING "")
     endif()
diff --git a/test/Driver/sanitize_coverage.swift b/test/Driver/sanitize_coverage.swift
index e41562a7a4c2f..3192f24945169 100644
--- a/test/Driver/sanitize_coverage.swift
+++ b/test/Driver/sanitize_coverage.swift
@@ -1,3 +1,5 @@
+// UNSUPPORTED: OS=windows-msvc
+
 // Different sanitizer coverage types
 // RUN: %swiftc_driver -driver-print-jobs -sanitize-coverage=func -sanitize=address %s | %FileCheck -check-prefix=SANCOV_FUNC %s
 // RUN: %swiftc_driver -driver-print-jobs -sanitize-coverage=bb -sanitize=address %s | %FileCheck -check-prefix=SANCOV_BB %s
diff --git a/test/IRGen/address_sanitizer_use_odr_indicator.swift b/test/IRGen/address_sanitizer_use_odr_indicator.swift
index 1ed723e25c08e..a529a4067cbfa 100644
--- a/test/IRGen/address_sanitizer_use_odr_indicator.swift
+++ b/test/IRGen/address_sanitizer_use_odr_indicator.swift
@@ -1,3 +1,4 @@
+// UNSUPPORTED: OS=windows-msvc
 // REQUIRES: asan_runtime
 
 // Default instrumentation that does not use ODR indicators
diff --git a/test/Interpreter/indirect_enum.swift b/test/Interpreter/indirect_enum.swift
index 3f5359ed360a7..fdc54ed5ff400 100644
--- a/test/Interpreter/indirect_enum.swift
+++ b/test/Interpreter/indirect_enum.swift
@@ -1,3 +1,5 @@
+// UNSUPPORTED: OS=windows-msvc
+
 // RUN: %target-swiftc_driver %s -g -sanitize=address -o %t_asan-binary
 // RUN: %target-codesign %t_asan-binary
 // RUN: env ASAN_OPTIONS=detect_leaks=0 %target-run %t_asan-binary
diff --git a/test/Reflection/typeref_decoding_asan.swift b/test/Reflection/typeref_decoding_asan.swift
index 2bd6be187db44..8ddc7ae2c1489 100644
--- a/test/Reflection/typeref_decoding_asan.swift
+++ b/test/Reflection/typeref_decoding_asan.swift
@@ -1,4 +1,5 @@
 // UNSUPPORTED: OS=linux-gnu && CPU=aarch64
+// UNSUPPORTED: OS=windows-msvc
 
 // rdar://100805115
 // UNSUPPORTED: CPU=arm64e
diff --git a/test/Sanitizers/asan/asan.swift b/test/Sanitizers/asan/asan.swift
index 3b2005523a009..b929582346856 100644
--- a/test/Sanitizers/asan/asan.swift
+++ b/test/Sanitizers/asan/asan.swift
@@ -1,3 +1,5 @@
+// UNSUPPORTED: OS=windows-msvc
+
 // RUN: %target-swiftc_driver %s -g -sanitize=address -o %t_asan-binary
 // RUN: %target-codesign %t_asan-binary
 // RUN: env %env-ASAN_OPTIONS=abort_on_error=0 not %target-run %t_asan-binary 2>&1 | %FileCheck %s
diff --git a/test/Sanitizers/sanitizer_coverage.swift b/test/Sanitizers/sanitizer_coverage.swift
index 8044beeb37033..a945d63994c70 100644
--- a/test/Sanitizers/sanitizer_coverage.swift
+++ b/test/Sanitizers/sanitizer_coverage.swift
@@ -9,6 +9,7 @@
 // For now restrict this test to platforms where we know this test will pass
 // REQUIRES: CPU=x86_64
 // UNSUPPORTED: remote_run
+// UNSUPPORTED: OS=windows-msvc
 
 func sayHello() {
   print("Hello")
diff --git a/utils/build.ps1 b/utils/build.ps1
index cb800f768d3c4..942c3464e8bc2 100644
--- a/utils/build.ps1
+++ b/utils/build.ps1
@@ -1764,6 +1764,21 @@ function Build-CURL([Platform]$Platform, $Arch) {
     })
 }
 
+function Build-Sanitizers([Platform]$Platform, $Arch, $InstallTo) {
+  Isolate-EnvVars {
+    # Use configured compilers
+    Build-CMakeProject `
+      -Src $SourceCache\llvm-project\runtimes `
+      -Bin "$(Get-HostProjectBinaryCache Compilers)\runtimes\runtimes-$($Arch.LLVMTarget)-bins" `
+      -InstallTo $InstallTo `
+      -Arch $Arch `
+      -Platform $Platform `
+      -Defines (@{
+        COMPILER_RT_BUILD_SANITIZERS = "YES"
+      })
+  }
+}
+
 function Build-Runtime([Platform]$Platform, $Arch) {
   $PlatformDefines = @{}
   if ($Platform -eq "Android") {
@@ -2756,6 +2771,11 @@ if (-not $SkipBuild) {
 
   Invoke-BuildStep Build-CMark $HostArch
   Invoke-BuildStep Build-Compilers $HostArch
+
+  $InstallTo = "$($HostArch.ToolchainInstallRoot)\usr"
+  foreach ($Arch in $WindowsSDKArchs) {
+    Invoke-BuildStep Build-Sanitizers Windows $Arch $InstallTo
+  }
 }
 
 if ($Clean) {