PCH: add target_precompile_headers command

Source/CMakeLists.txt

@@ -656,6 +656,8 @@ set(SRCS
   cmTargetLinkDirectoriesCommand.h
   cmTargetLinkLibrariesCommand.cxx
   cmTargetLinkLibrariesCommand.h
+  cmTargetPrecompileHeadersCommand.cxx
+  cmTargetPrecompileHeadersCommand.h
   cmTargetPropCommandBase.cxx
   cmTargetPropCommandBase.h
   cmTargetSourcesCommand.cxx

Source/cmCommands.cxx

@@ -78,6 +78,7 @@
 #include "cmTargetCompileOptionsCommand.h"
 #include "cmTargetIncludeDirectoriesCommand.h"
 #include "cmTargetLinkLibrariesCommand.h"
+#include "cmTargetPrecompileHeadersCommand.h"
 #include "cmTargetSourcesCommand.h"
 #include "cmTryCompileCommand.h"
 #include "cmTryRunCommand.h"
@@ -277,6 +278,9 @@ void GetProjectCommands(cmState* state)
   state->AddBuiltinCommand("try_compile",
                            cm::make_unique<cmTryCompileCommand>());
   state->AddBuiltinCommand("try_run", cm::make_unique<cmTryRunCommand>());
+  state->AddBuiltinCommand(
+    "target_precompile_headers",
+    cm::make_unique<cmTargetPrecompileHeadersCommand>());
 
 #if !defined(CMAKE_BOOTSTRAP)
   state->AddBuiltinCommand("add_compile_definitions",

Source/cmTargetPrecompileHeadersCommand.cxx

@@ -0,0 +1,36 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#include "cmTargetPrecompileHeadersCommand.h"
+
+#include "cmMakefile.h"
+#include "cmMessageType.h"
+#include "cmStringAlgorithms.h"
+#include "cmTarget.h"
+
+bool cmTargetPrecompileHeadersCommand::InitialPass(
+  std::vector<std::string> const& args, cmExecutionStatus&)
+{
+  return this->HandleArguments(args, "PRECOMPILE_HEADERS");
+}
+
+void cmTargetPrecompileHeadersCommand::HandleMissingTarget(
+  const std::string& name)
+{
+  const std::string e =
+    cmStrCat("Cannot specify precompile headers for target \"", name,
+             "\" which is not built by this project.");
+  this->Makefile->IssueMessage(MessageType::FATAL_ERROR, e);
+}
+
+std::string cmTargetPrecompileHeadersCommand::Join(
+  const std::vector<std::string>& content)
+{
+  return cmJoin(content, ";");
+}
+
+bool cmTargetPrecompileHeadersCommand::HandleDirectContent(
+  cmTarget* tgt, const std::vector<std::string>& content, bool, bool)
+{
+  tgt->AppendProperty("PRECOMPILE_HEADERS", this->Join(content).c_str());
+  return true;
+}

Source/cmTargetPrecompileHeadersCommand.h

@@ -0,0 +1,41 @@
+/* Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
+   file Copyright.txt or https://cmake.org/licensing for details.  */
+#ifndef cmTargetPrecompileHeadersCommand_h
+#define cmTargetPrecompileHeadersCommand_h
+
+#include "cmConfigure.h" // IWYU pragma: keep
+
+#include <string>
+#include <vector>
+
+#include "cm_memory.hxx"
+
+#include "cmCommand.h"
+
+#include "cmTargetPropCommandBase.h"
+
+class cmExecutionStatus;
+class cmTarget;
+
+class cmTargetPrecompileHeadersCommand : public cmTargetPropCommandBase
+{
+public:
+  std::unique_ptr<cmCommand> Clone() override
+  {
+    return cm::make_unique<cmTargetPrecompileHeadersCommand>();
+  }
+
+  bool InitialPass(std::vector<std::string> const& args,
+                   cmExecutionStatus& status) override;
+
+private:
+  void HandleMissingTarget(const std::string& name) override;
+
+  bool HandleDirectContent(cmTarget* tgt,
+                           const std::vector<std::string>& content,
+                           bool prepend, bool system) override;
+
+  std::string Join(const std::vector<std::string>& content) override;
+};
+
+#endif

bootstrap

@@ -436,6 +436,7 @@ CMAKE_CXX_SOURCES="\
   cmTargetCompileOptionsCommand \
   cmTargetIncludeDirectoriesCommand \
   cmTargetLinkLibrariesCommand \
+  cmTargetPrecompileHeadersCommand \
   cmTargetPropCommandBase \
   cmTargetPropertyComputer \
   cmTargetSourcesCommand \