build: workaround for VC v14.25 / MSVC 19.25

Adds a temporary fix to vs_toolchain.py to use the previous version of
MSVC's header files and documents how to install the previous version
alongside 19.25.

Bug: 1058860
Change-Id: I6e96af3c71b23e5c5430237d00125a5830c37855
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2117732
Commit-Queue: Richard Townsend <richard.townsend@arm.com>
Reviewed-by: Nico Weber <thakis@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#753998}

build/toolchain/win/setup_toolchain.py

@@ -158,6 +158,11 @@ def _LoadToolchainEnv(cpu, sdk_dir, target_store):
     if (target_store):
       args.append(['store'])
     variables = _LoadEnvFromBat(args)
+    # Check for faulty 14.25 version of system headers (see crbug.com/1058860).
+    if "14.25" in _ExtractImportantEnvironment(variables)["LIB"]:
+      # If detected, switch back to 14.24.
+      args.append(["-vcvars_ver=14.24"])
+      variables = _LoadEnvFromBat(args)
   return _ExtractImportantEnvironment(variables)
 
 

build/vs_toolchain.py

@@ -320,11 +320,21 @@ def FindVCComponentRoot(component):
   vc_component_msvc_contents = os.listdir(vc_component_msvc_root)
   # Select the most recent toolchain if there are several.
   _SortByHighestVersionNumberFirst(vc_component_msvc_contents)
+  acceptable_msvc_version_found = False
   for directory in vc_component_msvc_contents:
+    if directory.startswith('14.25'):
+      print(
+          "Warning: known issue affecting the headers distributed with VC version {}."
+          .format(directory))
+      print("See https://crbug.com/1063424 for details.")
+      continue
+    acceptable_msvc_version_found = True
     if not os.path.isdir(os.path.join(vc_component_msvc_root, directory)):
       continue
     if re.match(r'14\.\d+\.\d+', directory):
       return os.path.join(vc_component_msvc_root, directory)
+  if not acceptable_msvc_version_found:
+    raise Exception("Unable to find a suitable VC version.")
   raise Exception('Unable to find the VC %s directory.' % component)
 
 

docs/windows_build_instructions.md

@@ -61,6 +61,22 @@ Software Development Kit" → Change → Change → Check "Debugging Tools For
 Windows" → Change. Or, you can download the standalone SDK installer and use it
 to install the Debugging Tools.
 
+### Known issue with Visual Studio 16.5.0
+Visual Studio 16.5.0 includes some header files which are incompatible with the
+C++ standard used in Chromium (see [crbug.com/1063424](https://crbug.com/1063424)
+for details.) A workaround is to install the older command-line tools:
+```shell
+$ PATH_TO_INSTALLER.exe ^
+    --add "Microsoft.VisualStudio.Component.VC.14.24.ARM64" ^
+    --add "Microsoft.VisualStudio.Component.VC.14.24.x86.x64" ^
+    --add "Microsoft.VisualStudio.Component.VC.14.24.ATL.ARM64" ^
+    --add "Microsoft.VisualStudio.Component.VC.14.24.ATL" ^
+    --add "Microsoft.VisualStudio.Component.VC.14.24.MFC.ARM64" ^
+    --add "Microsoft.VisualStudio.Component.VC.14.24.MFC" ^
+    --includeRecommended
+```
+
+
 ## Install `depot_tools`
 
 Download the [depot_tools bundle](https://storage.googleapis.com/chrome-infra/depot_tools.zip)