Add options to run include-what-you-use with the compiler

Create a <LANG>_INCLUDE_WHAT_YOU_USE target property (initialized by a
CMAKE_<LANG>_INCLUDE_WHAT_YOU_USE variable) to specify an IWYU command
line to be run along with the compiler.

Help/manual/cmake-properties.7.rst

@@ -177,6 +177,7 @@ Properties on Targets
    /prop_tgt/JOB_POOL_COMPILE
    /prop_tgt/JOB_POOL_LINK
    /prop_tgt/LABELS
+   /prop_tgt/LANG_INCLUDE_WHAT_YOU_USE
    /prop_tgt/LANG_VISIBILITY_PRESET
    /prop_tgt/LIBRARY_OUTPUT_DIRECTORY_CONFIG
    /prop_tgt/LIBRARY_OUTPUT_DIRECTORY

Help/manual/cmake-variables.7.rst

@@ -235,6 +235,7 @@ Variables that Control the Build
    /variable/CMAKE_INSTALL_NAME_DIR
    /variable/CMAKE_INSTALL_RPATH
    /variable/CMAKE_INSTALL_RPATH_USE_LINK_PATH
+   /variable/CMAKE_LANG_INCLUDE_WHAT_YOU_USE
    /variable/CMAKE_LANG_VISIBILITY_PRESET
    /variable/CMAKE_LIBRARY_OUTPUT_DIRECTORY
    /variable/CMAKE_LIBRARY_OUTPUT_DIRECTORY_CONFIG

Help/prop_tgt/LANG_INCLUDE_WHAT_YOU_USE.rst

@@ -0,0 +1,13 @@
+<LANG>_INCLUDE_WHAT_YOU_USE
+---------------------------
+
+This property is implemented only when ``<LANG>`` is ``C`` or ``CXX``.
+
+Specify a :ref:`;-list <CMake Language Lists>` containing a command
+line for the ``include-what-you-use`` tool.  The :ref:`Makefile Generators`
+and the :generator:`Ninja` generator will run this tool along with the
+compiler and report a warning if the tool reports any problems.
+
+This property is initialized by the value of
+the :variable:`CMAKE_<LANG>_INCLUDE_WHAT_YOU_USE` variable if it is set
+when a target is created.

Help/release/dev/run-include-what-you-use.rst

@@ -0,0 +1,8 @@
+run-include-what-you-use
+------------------------
+
+* The :ref:`Makefile Generators` and the :generator:`Ninja` generator
+  learned to optionally run ``include-what-you-use`` along with the
+  compiler for ``C`` and ``CXX`` languages.  See the
+  :variable:`CMAKE_<LANG>_INCLUDE_WHAT_YOU_USE` variable and
+  :prop_tgt:`<LANG>_INCLUDE_WHAT_YOU_USE` target property for details.

Help/variable/CMAKE_LANG_INCLUDE_WHAT_YOU_USE.rst

@@ -0,0 +1,6 @@
+CMAKE_<LANG>_INCLUDE_WHAT_YOU_USE
+---------------------------------
+
+Default value for :prop_tgt:`<LANG>_INCLUDE_WHAT_YOU_USE` target property.
+This variable is used to initialize the property on each target as it is
+created.  This is done only when ``<LANG>`` is ``C`` or ``CXX``.

Source/cmMakefileTargetGenerator.cxx

@@ -768,6 +768,20 @@ cmMakefileTargetGenerator
     this->LocalGenerator->ExpandRuleVariables(*i, vars);
     }
 
+  // Maybe insert an include-what-you-use runner.
+  if (!compileCommands.empty() && (lang == "C" || lang == "CXX"))
+    {
+    std::string const iwyu_prop = lang + "_INCLUDE_WHAT_YOU_USE";
+    const char *iwyu = this->Target->GetProperty(iwyu_prop);
+    if (iwyu && *iwyu)
+      {
+      std::string run_iwyu = "$(CMAKE_COMMAND) -E __run_iwyu --iwyu=";
+      run_iwyu += this->LocalGenerator->EscapeForShell(iwyu);
+      run_iwyu += " -- ";
+      compileCommands.front().insert(0, run_iwyu);
+      }
+    }
+
   // Change the command working directory to the local build tree.
   this->LocalGenerator->CreateCDCommand
     (compileCommands,

Source/cmNinjaTargetGenerator.cxx

@@ -458,6 +458,23 @@ cmNinjaTargetGenerator
   std::vector<std::string> compileCmds;
   cmSystemTools::ExpandListArgument(compileCmd, compileCmds);
 
+  // Maybe insert an include-what-you-use runner.
+  if (!compileCmds.empty() && (lang == "C" || lang == "CXX"))
+    {
+    std::string const iwyu_prop = lang + "_INCLUDE_WHAT_YOU_USE";
+    const char *iwyu = this->Target->GetProperty(iwyu_prop);
+    if (iwyu && *iwyu)
+      {
+      std::string run_iwyu =
+        this->GetLocalGenerator()->ConvertToOutputFormat(
+          cmSystemTools::GetCMakeCommand(), cmLocalGenerator::SHELL);
+      run_iwyu += " -E __run_iwyu --iwyu=";
+      run_iwyu += this->GetLocalGenerator()->EscapeForShell(iwyu);
+      run_iwyu += " -- ";
+      compileCmds.front().insert(0, run_iwyu);
+      }
+    }
+
   if (!compileCmds.empty())
     {
     compileCmds.front().insert(0, cldeps);

Source/cmTarget.cxx

@@ -333,9 +333,11 @@ void cmTarget::SetMakefile(cmMakefile* mf)
     this->SetPropertyDefault("MACOSX_BUNDLE", 0);
     this->SetPropertyDefault("MACOSX_RPATH", 0);
     this->SetPropertyDefault("NO_SYSTEM_FROM_IMPORTED", 0);
+    this->SetPropertyDefault("C_INCLUDE_WHAT_YOU_USE", 0);
     this->SetPropertyDefault("C_STANDARD", 0);
     this->SetPropertyDefault("C_STANDARD_REQUIRED", 0);
     this->SetPropertyDefault("C_EXTENSIONS", 0);
+    this->SetPropertyDefault("CXX_INCLUDE_WHAT_YOU_USE", 0);
     this->SetPropertyDefault("CXX_STANDARD", 0);
     this->SetPropertyDefault("CXX_STANDARD_REQUIRED", 0);
     this->SetPropertyDefault("CXX_EXTENSIONS", 0);

Tests/RunCMake/CMakeLists.txt

@@ -241,3 +241,8 @@ if(CMAKE_OSX_ARCHITECTURES AND XCODE AND NOT "${XCODE_VERSION}" MATCHES "^[^12]"
     PRE_BUILD COMMAND ${CMAKE_COMMAND} -E make_directory "${CMAKE_CFG_INTDIR}"
     )
 endif()
+
+if("${CMAKE_GENERATOR}" MATCHES "Make|Ninja")
+  add_executable(pseudo_iwyu pseudo_iwyu.c)
+  add_RunCMake_test(IncludeWhatYouUse -DPSEUDO_IWYU=$<TARGET_FILE:pseudo_iwyu>)
+endif()

Tests/RunCMake/IncludeWhatYouUse/C-Build-stdout.txt

@@ -0,0 +1,4 @@
+Warning: include-what-you-use reported diagnostics:
+should add these lines:
+*
+#include <\.\.\.>

Tests/RunCMake/IncludeWhatYouUse/C.cmake

@@ -0,0 +1,3 @@
+enable_language(C)
+set(CMAKE_C_INCLUDE_WHAT_YOU_USE "${PSEUDO_IWYU}" -some -args)
+add_executable(main main.c)

Tests/RunCMake/IncludeWhatYouUse/CMakeLists.txt

@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.2)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake)

Tests/RunCMake/IncludeWhatYouUse/CXX-Build-stdout.txt

@@ -0,0 +1,4 @@
+Warning: include-what-you-use reported diagnostics:
+should add these lines:
+*
+#include <\.\.\.>

Tests/RunCMake/IncludeWhatYouUse/CXX.cmake

@@ -0,0 +1,3 @@
+enable_language(CXX)
+set(CMAKE_CXX_INCLUDE_WHAT_YOU_USE "${PSEUDO_IWYU}" -some -args)
+add_executable(main main.cxx)

Tests/RunCMake/IncludeWhatYouUse/RunCMakeTest.cmake

@@ -0,0 +1,18 @@
+include(RunCMake)
+
+set(RunCMake_TEST_OPTIONS "-DPSEUDO_IWYU=${PSEUDO_IWYU}")
+
+function(run_iwyu lang)
+  # Use a single build tree for tests without cleaning.
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/${lang}-build)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  file(REMOVE_RECURSE "${RunCMake_TEST_BINARY_DIR}")
+  file(MAKE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}")
+  run_cmake(${lang})
+
+  set(RunCMake_TEST_OUTPUT_MERGE 1)
+  run_cmake_command(${lang}-Build ${CMAKE_COMMAND} --build .)
+endfunction()
+
+run_iwyu(C)
+run_iwyu(CXX)

Tests/RunCMake/IncludeWhatYouUse/main.c

@@ -0,0 +1 @@
+int main(void) { return 0; }

Tests/RunCMake/IncludeWhatYouUse/main.cxx

@@ -0,0 +1 @@
+int main() { return 0; }

Tests/RunCMake/pseudo_iwyu.c

@@ -0,0 +1,7 @@
+#include <stdio.h>
+
+int main(void)
+{
+  fprintf(stderr, "should add these lines:\n#include <...>\n");
+  return 0;
+}