16 files changed, 112 insertions, 29 deletions
diff --git a/Help/command/if.rst b/Help/command/if.rst
index c51d2bc..5dabe00 100644
--- a/Help/command/if.rst
+++ b/Help/command/if.rst
@@ -119,9 +119,10 @@ File Operations
 
 ``if(EXISTS path-to-file-or-directory)``
  True if the named file or directory exists.  Behavior is well-defined
- only for full paths. Resolves symbolic links, i.e. if the named file or
- directory is a symbolic link, returns true if the target of the
- symbolic link exists.
+ only for explicit full paths (a leading ``~/`` is not expanded as
+ a home directory and is considered a relative path).
+ Resolves symbolic links, i.e. if the named file or directory is a
+ symbolic link, returns true if the target of the symbolic link exists.
 
 ``if(file1 IS_NEWER_THAN file2)``
  True if ``file1`` is newer than ``file2`` or if one of the two files doesn't
diff --git a/Modules/InstallRequiredSystemLibraries.cmake b/Modules/InstallRequiredSystemLibraries.cmake
index 6ecdb9c..a39393dc 100644
--- a/Modules/InstallRequiredSystemLibraries.cmake
+++ b/Modules/InstallRequiredSystemLibraries.cmake
@@ -101,16 +101,18 @@ endforeach()
 if(MSVC)
   file(TO_CMAKE_PATH "$ENV{SYSTEMROOT}" SYSTEMROOT)
 
-  if(CMAKE_CL_64)
-    if(MSVC_VERSION GREATER 1599)
-      # VS 10 and later:
-      set(CMAKE_MSVC_ARCH x64)
-    else()
+  if(MSVC_C_ARCHITECTURE_ID)
+    string(TOLOWER "${MSVC_C_ARCHITECTURE_ID}" CMAKE_MSVC_ARCH)
+  elseif(MSVC_CXX_ARCHITECTURE_ID)
+    string(TOLOWER "${MSVC_CXX_ARCHITECTURE_ID}" CMAKE_MSVC_ARCH)
+  else()
+    set(CMAKE_MSVC_ARCH x86)
+  endif()
+  if(CMAKE_MSVC_ARCH STREQUAL "x64")
+    if(MSVC_VERSION LESS 1600)
       # VS 9 and earlier:
       set(CMAKE_MSVC_ARCH amd64)
     endif()
-  else()
-    set(CMAKE_MSVC_ARCH x86)
   endif()
 
   get_filename_component(devenv_dir "${CMAKE_MAKE_PROGRAM}" PATH)
diff --git a/Source/CMakeVersion.cmake b/Source/CMakeVersion.cmake
index 113a9d8..2480380 100644
--- a/Source/CMakeVersion.cmake
+++ b/Source/CMakeVersion.cmake
@@ -1,7 +1,7 @@
 # CMake version number components.
 set(CMake_VERSION_MAJOR 3)
 set(CMake_VERSION_MINOR 19)
-set(CMake_VERSION_PATCH 20210125)
+set(CMake_VERSION_PATCH 20210127)
 #set(CMake_VERSION_RC 0)
 set(CMake_VERSION_IS_DIRTY 0)
 
diff --git a/Source/cmLocalGenerator.cxx b/Source/cmLocalGenerator.cxx
index 86eddc2..a6d898d 100644
--- a/Source/cmLocalGenerator.cxx
+++ b/Source/cmLocalGenerator.cxx
@@ -2768,17 +2768,32 @@ inline void RegisterUnitySources(cmGeneratorTarget* target, cmSourceFile* sf,
   target->AddSourceFileToUnityBatch(sf->ResolveFullPath());
   sf->SetProperty("UNITY_SOURCE_FILE", filename.c_str());
 }
+}
 
-inline void IncludeFileInUnitySources(cmGeneratedFileStream& unity_file,
-                                      std::string const& sf_full_path,
-                                      cmProp beforeInclude,
-                                      cmProp afterInclude, cmProp uniqueIdName)
+void cmLocalGenerator::IncludeFileInUnitySources(
+  cmGeneratedFileStream& unity_file, std::string const& sf_full_path,
+  cmProp beforeInclude, cmProp afterInclude, cmProp uniqueIdName)
 {
-
   if (uniqueIdName && !uniqueIdName->empty()) {
-    unity_file << "#undef " << *uniqueIdName << "\n"
+    std::string pathToHash;
+    auto PathEqOrSubDir = [](std::string const& a, std::string const& b) {
+      return (cmSystemTools::ComparePath(a, b) ||
+              cmSystemTools::IsSubDirectory(a, b));
+    };
+    const auto path = cmSystemTools::GetFilenamePath(sf_full_path);
+    if (PathEqOrSubDir(path, this->GetBinaryDirectory())) {
+      pathToHash = "BLD_" +
+        cmSystemTools::RelativePath(this->GetBinaryDirectory(), sf_full_path);
+    } else if (PathEqOrSubDir(path, this->GetSourceDirectory())) {
+      pathToHash = "SRC_" +
+        cmSystemTools::RelativePath(this->GetSourceDirectory(), sf_full_path);
+    } else {
+      pathToHash = "ABS_" + sf_full_path;
+    }
+    unity_file << "/* " << pathToHash << " */\n"
+               << "#undef " << *uniqueIdName << "\n"
                << "#define " << *uniqueIdName << " unity_"
-               << cmSystemTools::ComputeStringMD5(sf_full_path) << "\n";
+               << cmSystemTools::ComputeStringMD5(pathToHash) << "\n";
   }
 
   if (beforeInclude) {
@@ -2790,9 +2805,10 @@ inline void IncludeFileInUnitySources(cmGeneratedFileStream& unity_file,
   if (afterInclude) {
     unity_file << *afterInclude << "\n";
   }
+  unity_file << "\n";
 }
 
-std::vector<std::string> AddUnityFilesModeAuto(
+std::vector<std::string> cmLocalGenerator::AddUnityFilesModeAuto(
   cmGeneratorTarget* target, std::string const& lang,
   std::vector<cmSourceFile*> const& filtered_sources, cmProp beforeInclude,
   cmProp afterInclude, std::string const& filename_base, size_t batchSize)
@@ -2835,7 +2851,7 @@ std::vector<std::string> AddUnityFilesModeAuto(
   return unity_files;
 }
 
-std::vector<std::string> AddUnityFilesModeGroup(
+std::vector<std::string> cmLocalGenerator::AddUnityFilesModeGroup(
   cmGeneratorTarget* target, std::string const& lang,
   std::vector<cmSourceFile*> const& filtered_sources, cmProp beforeInclude,
   cmProp afterInclude, std::string const& filename_base)
@@ -2883,7 +2899,6 @@ std::vector<std::string> AddUnityFilesModeGroup(
 
   return unity_files;
 }
-}
 
 void cmLocalGenerator::AddUnityBuild(cmGeneratorTarget* target)
 {
diff --git a/Source/cmLocalGenerator.h b/Source/cmLocalGenerator.h
index 91dd8ae..a3610fd 100644
--- a/Source/cmLocalGenerator.h
+++ b/Source/cmLocalGenerator.h
@@ -4,6 +4,7 @@
 
 #include "cmConfigure.h" // IWYU pragma: keep
 
+#include <cstddef>
 #include <iosfwd>
 #include <map>
 #include <memory>
@@ -27,6 +28,7 @@ class cmComputeLinkInformation;
 class cmCustomCommand;
 class cmCustomCommandGenerator;
 class cmCustomCommandLines;
+class cmGeneratedFileStream;
 class cmGeneratorTarget;
 class cmGlobalGenerator;
 class cmImplicitDependsList;
@@ -651,6 +653,18 @@ private:
                          const std::string& ReuseFrom,
                          cmGeneratorTarget* reuseTarget,
                          std::vector<std::string> const& extensions);
+  void IncludeFileInUnitySources(cmGeneratedFileStream& unity_file,
+                                 std::string const& sf_full_path,
+                                 cmProp beforeInclude, cmProp afterInclude,
+                                 cmProp uniqueIdName);
+  std::vector<std::string> AddUnityFilesModeAuto(
+    cmGeneratorTarget* target, std::string const& lang,
+    std::vector<cmSourceFile*> const& filtered_sources, cmProp beforeInclude,
+    cmProp afterInclude, std::string const& filename_base, size_t batchSize);
+  std::vector<std::string> AddUnityFilesModeGroup(
+    cmGeneratorTarget* target, std::string const& lang,
+    std::vector<cmSourceFile*> const& filtered_sources, cmProp beforeInclude,
+    cmProp afterInclude, std::string const& filename_base);
 };
 
 #if !defined(CMAKE_BOOTSTRAP)
diff --git a/Source/cmNinjaUtilityTargetGenerator.cxx b/Source/cmNinjaUtilityTargetGenerator.cxx
index 3995624..a18ca20 100644
--- a/Source/cmNinjaUtilityTargetGenerator.cxx
+++ b/Source/cmNinjaUtilityTargetGenerator.cxx
@@ -35,6 +35,11 @@ cmNinjaUtilityTargetGenerator::~cmNinjaUtilityTargetGenerator() = default;
 
 void cmNinjaUtilityTargetGenerator::Generate(const std::string& config)
 {
+  if (!this->GetGeneratorTarget()->Target->IsPerConfig()) {
+    this->WriteUtilBuildStatements(config, config);
+    return;
+  }
+
   for (auto const& fileConfig : this->GetConfigNames()) {
     if (!this->GetGlobalGenerator()
            ->GetCrossConfigs(fileConfig)
@@ -122,8 +127,6 @@ void cmNinjaUtilityTargetGenerator::WriteUtilBuildStatements(
     std::copy(util_outputs.begin(), util_outputs.end(),
               std::back_inserter(gg->GetByproductsForCleanTarget()));
   }
-  // TODO: Does this need an output config?
-  // Does this need to go in impl-<config>.ninja?
   lg->AppendTargetDepends(genTarget, deps, config, fileConfig,
                           DependOnTargetArtifact);
 
diff --git a/Source/kwsys/ProcessWin32.c b/Source/kwsys/ProcessWin32.c
index 1267076..8f01684 100644
--- a/Source/kwsys/ProcessWin32.c
+++ b/Source/kwsys/ProcessWin32.c
@@ -962,7 +962,10 @@ void kwsysProcess_Execute(kwsysProcess* cp)
       kwsysProcessCleanup(cp, GetLastError());
       return;
     }
-    SetCurrentDirectoryW(cp->WorkingDirectory);
+    if (!SetCurrentDirectoryW(cp->WorkingDirectory)) {
+      kwsysProcessCleanup(cp, GetLastError());
+      return;
+    }
   }
 
   /* Setup the stdin pipe for the first process.  */
diff --git a/Templates/MSBuild/FlagTables/v142_CSharp.json b/Templates/MSBuild/FlagTables/v142_CSharp.json
index 5989aea..4dcea9d 100644
--- a/Templates/MSBuild/FlagTables/v142_CSharp.json
+++ b/Templates/MSBuild/FlagTables/v142_CSharp.json
@@ -201,6 +201,13 @@
     "flags": []
   },
   {
+    "name":  "DebugType",
+    "switch": "debug:portable",
+    "comment": "",
+    "value": "portable",
+    "flags": []
+  },
+  {
     "name":  "Optimize",
     "switch": "optimize",
     "comment": "",
@@ -264,6 +271,17 @@
     "flags": []
   },
   {
+    "name":  "WarningsAsErrors",
+    "switch": "warnaserror:",
+    "comment": "",
+    "value": "",
+    "flags": [
+      "UserValue",
+      "UserRequired",
+      "CommaAppendable"
+    ]
+  },
+  {
     "name":  "WarningLevel",
     "switch": "warn:0",
     "comment": "",
diff --git a/Tests/RunCMake/NinjaMultiConfig/RunCMakeTest.cmake b/Tests/RunCMake/NinjaMultiConfig/RunCMakeTest.cmake
index 480d628..21c2658 100644
--- a/Tests/RunCMake/NinjaMultiConfig/RunCMakeTest.cmake
+++ b/Tests/RunCMake/NinjaMultiConfig/RunCMakeTest.cmake
@@ -85,6 +85,9 @@ set(RunCMake_TEST_OPTIONS "-DCMAKE_CONFIGURATION_TYPES=RelWithDebInfo\\;Debug\\;
 run_cmake_configure(Simple)
 unset(RunCMake_TEST_OPTIONS)
 include(${RunCMake_TEST_BINARY_DIR}/target_files.cmake)
+run_ninja(Simple targets-default build.ninja -t targets)
+run_ninja(Simple targets-debug build-Debug.ninja -t targets)
+run_ninja(Simple targets-release build-Debug.ninja -t targets)
 run_cmake_build(Simple debug-target Debug simpleexe)
 run_ninja(Simple debug-target build-Debug.ninja simplestatic)
 get_filename_component(simpleshared_Release "${TARGET_FILE_simpleshared_Release}" NAME)
diff --git a/Tests/RunCMake/NinjaMultiConfig/Simple-targets-debug-ninja-stdout.txt b/Tests/RunCMake/NinjaMultiConfig/Simple-targets-debug-ninja-stdout.txt
new file mode 100644
index 0000000..f72516f
--- /dev/null
+++ b/Tests/RunCMake/NinjaMultiConfig/Simple-targets-debug-ninja-stdout.txt
@@ -0,0 +1,3 @@
+(rebuild_cache: phony.*
+edit_cache: phony|edit_cache: phony.*
+rebuild_cache: phony)
diff --git a/Tests/RunCMake/NinjaMultiConfig/Simple-targets-default-ninja-stdout.txt b/Tests/RunCMake/NinjaMultiConfig/Simple-targets-default-ninja-stdout.txt
new file mode 100644
index 0000000..f72516f
--- /dev/null
+++ b/Tests/RunCMake/NinjaMultiConfig/Simple-targets-default-ninja-stdout.txt
@@ -0,0 +1,3 @@
+(rebuild_cache: phony.*
+edit_cache: phony|edit_cache: phony.*
+rebuild_cache: phony)
diff --git a/Tests/RunCMake/NinjaMultiConfig/Simple-targets-release-ninja-stdout.txt b/Tests/RunCMake/NinjaMultiConfig/Simple-targets-release-ninja-stdout.txt
new file mode 100644
index 0000000..f72516f
--- /dev/null
+++ b/Tests/RunCMake/NinjaMultiConfig/Simple-targets-release-ninja-stdout.txt
@@ -0,0 +1,3 @@
+(rebuild_cache: phony.*
+edit_cache: phony|edit_cache: phony.*
+rebuild_cache: phony)
diff --git a/Tests/RunCMake/UnityBuild/f.cxx b/Tests/RunCMake/UnityBuild/f.cxx
new file mode 100644
index 0000000..d5813c6
--- /dev/null
+++ b/Tests/RunCMake/UnityBuild/f.cxx
@@ -0,0 +1,5 @@
+int f(int x)
+{
+  (void)x;
+  return 0;
+}
diff --git a/Tests/RunCMake/UnityBuild/unitybuild_anon_ns-build-check.cmake b/Tests/RunCMake/UnityBuild/unitybuild_anon_ns-build-check.cmake
new file mode 100644
index 0000000..746be32
--- /dev/null
+++ b/Tests/RunCMake/UnityBuild/unitybuild_anon_ns-build-check.cmake
@@ -0,0 +1,10 @@
+set(unitybuild_0 "${RunCMake_TEST_BINARY_DIR}/CMakeFiles/tgt.dir/Unity/unity_0_cxx.cxx")
+
+file(STRINGS ${unitybuild_0} src)
+
+foreach(expectedRegex IN ITEMS "SRC_f\\.cxx" "BLD_s1\\.cpp")
+  if(NOT "${src}" MATCHES "${expectedRegex}")
+    set(RunCMake_TEST_FAILED "Generated unity file doesn't have a match for expected unity ID regex ${expectedRegex}")
+    return()
+  endif()
+endforeach()
diff --git a/Tests/RunCMake/UnityBuild/unitybuild_anon_ns.cmake b/Tests/RunCMake/UnityBuild/unitybuild_anon_ns.cmake
index 6f4878f..e05863d 100644
--- a/Tests/RunCMake/UnityBuild/unitybuild_anon_ns.cmake
+++ b/Tests/RunCMake/UnityBuild/unitybuild_anon_ns.cmake
@@ -4,7 +4,7 @@ include(${CMAKE_CURRENT_SOURCE_DIR}/unitybuild_anon_ns_test_files.cmake)
 
 write_unity_build_anon_ns_test_files(srcs)
 
-add_library(tgt SHARED ${srcs})
+add_library(tgt SHARED f.cxx ${srcs})
 
 set_target_properties(tgt PROPERTIES UNITY_BUILD ON)
 
diff --git a/Utilities/std/cm/optional b/Utilities/std/cm/optional
index 0defae1..2ebc78c 100644
--- a/Utilities/std/cm/optional
+++ b/Utilities/std/cm/optional
@@ -313,7 +313,7 @@ bool operator!=(const optional<T>& opt, nullopt_t) noexcept
 }
 
 template <typename T>
-bool operator<(const optional<T>& opt, nullopt_t) noexcept
+bool operator<(const optional<T>& /*opt*/, nullopt_t) noexcept
 {
   return false;
 }
@@ -331,7 +331,7 @@ bool operator>(const optional<T>& opt, nullopt_t) noexcept
 }
 
 template <typename T>
-bool operator>=(const optional<T>& opt, nullopt_t) noexcept
+bool operator>=(const optional<T>& /*opt*/, nullopt_t) noexcept
 {
   return true;
 }
@@ -355,13 +355,13 @@ bool operator<(nullopt_t, const optional<T>& opt) noexcept
 }
 
 template <typename T>
-bool operator<=(nullopt_t, const optional<T>& opt) noexcept
+bool operator<=(nullopt_t, const optional<T>& /*opt*/) noexcept
 {
   return true;
 }
 
 template <typename T>
-bool operator>(nullopt_t, const optional<T>& opt) noexcept
+bool operator>(nullopt_t, const optional<T>& /*opt*/) noexcept
 {
   return false;
 }