cmake: Add options for parallel builds to --build mode

While we already support `cmake --build . -- -j`, the options after `--`
are specific to the native build tool.  Add new options `--parallel
[<N>]` and `-j [<N>]` to abstract this and map to the proper option
for the native build tool.

1 files changed, 37 insertions, 0 deletions

diff --git a/Source/cmGlobalNMakeMakefileGenerator.cxx b/Source/cmGlobalNMakeMakefileGenerator.cxx
index da683fb..eb66bd1 100644
--- a/Source/cmGlobalNMakeMakefileGenerator.cxx
+++ b/Source/cmGlobalNMakeMakefileGenerator.cxx
@@ -52,3 +52,40 @@ void cmGlobalNMakeMakefileGenerator::PrintCompilerAdvice(
   }
   this->cmGlobalUnixMakefileGenerator3::PrintCompilerAdvice(os, lang, envVar);
 }
+
+void cmGlobalNMakeMakefileGenerator::GenerateBuildCommand(
+  std::vector<std::string>& makeCommand, const std::string& makeProgram,
+  const std::string& projectName, const std::string& projectDir,
+  const std::string& targetName, const std::string& config, bool fast,
+  int /*jobs*/, bool verbose, std::vector<std::string> const& makeOptions)
+{
+  std::vector<std::string> nmakeMakeOptions;
+
+  // Since we have full control over the invocation of nmake, let us
+  // make it quiet.
+  nmakeMakeOptions.push_back(this->MakeSilentFlag);
+  nmakeMakeOptions.insert(nmakeMakeOptions.end(), makeOptions.begin(),
+                          makeOptions.end());
+
+  this->cmGlobalUnixMakefileGenerator3::GenerateBuildCommand(
+    makeCommand, makeProgram, projectName, projectDir, targetName, config,
+    fast, cmake::NO_BUILD_PARALLEL_LEVEL, verbose, nmakeMakeOptions);
+}
+
+void cmGlobalNMakeMakefileGenerator::PrintBuildCommandAdvice(std::ostream& os,
+                                                             int jobs) const
+{
+  if (jobs != cmake::NO_BUILD_PARALLEL_LEVEL) {
+    // nmake does not support parallel build level
+    // see https://msdn.microsoft.com/en-us/library/afyyse50.aspx
+
+    /* clang-format off */
+    os <<
+      "Warning: NMake does not support parallel builds. "
+      "Ignoring parallel build command line option.\n";
+    /* clang-format on */
+  }
+
+  this->cmGlobalUnixMakefileGenerator3::PrintBuildCommandAdvice(
+    os, cmake::NO_BUILD_PARALLEL_LEVEL);
+}