[gnome-builder] clang: move llvm flag discovery to clang plugin

[Christian Hergert <chergert src gnome org>]

commit 88c9e94014d0813f96983483996548a02bb7e068
Author: Christian Hergert <chergert redhat com>
Date:   Tue Nov 22 17:06:54 2016 -0800

    clang: move llvm flag discovery to clang plugin
    
    This really belongs in the clang plugin since it is specific to that
    compiler. Also, this fixes bug 774683 which is caused by no std include
    paths available for non-autotools projects.

 plugins/autotools/ide-makecache.c |  137 ++-----------------------------------
 plugins/clang/ide-clang-service.c |   75 +++++++++++++++++++--
 2 files changed, 74 insertions(+), 138 deletions(-)
---
diff --git a/plugins/autotools/ide-makecache.c b/plugins/autotools/ide-makecache.c
index 70e9a99..afae0f6 100644
--- a/plugins/autotools/ide-makecache.c
+++ b/plugins/autotools/ide-makecache.c
@@ -50,7 +50,6 @@ struct _IdeMakecache
 
   GFile        *makefile;
   GFile        *parent;
-  gchar        *llvm_flags;
   GMappedFile  *mapped;
   EggTaskCache *file_targets_cache;
   EggTaskCache *file_flags_cache;
@@ -140,98 +139,6 @@ ide_makecache_get_relative_path (IdeMakecache *self,
   return g_file_get_relative_path (workdir, file);
 }
 
-static void
-ide_makecache_discover_llvm_flags_worker (GTask        *task,
-                                          gpointer      source_object,
-                                          gpointer      task_data,
-                                          GCancellable *cancellable)
-{
-  g_autoptr(GSubprocess) subprocess = NULL;
-  g_autofree gchar *stdoutstr = NULL;
-  gchar *include_path = NULL;
-  GError *error = NULL;
-
-  IDE_ENTRY;
-
-  g_assert (G_IS_TASK (task));
-
-  IDE_TRACE_MSG ("Spawning 'clang -print-file-name=include'");
-
-  subprocess = g_subprocess_new (G_SUBPROCESS_FLAGS_STDOUT_PIPE,
-                                 &error,
-                                 "clang",
-                                 "-print-file-name=include",
-                                 NULL);
-
-  if (!subprocess)
-    {
-      g_assert (error != NULL);
-      g_task_return_error (task, error);
-      IDE_EXIT;
-    }
-
-  if (!g_subprocess_communicate_utf8 (subprocess, NULL, cancellable, &stdoutstr, NULL, &error))
-    {
-      g_assert (error != NULL);
-      g_task_return_error (task, error);
-      IDE_EXIT;
-    }
-
-  g_strstrip (stdoutstr);
-
-  IDE_TRACE_MSG ("Clang Result: %s", stdoutstr);
-
-  if (g_str_equal (stdoutstr, "include"))
-    {
-      g_task_return_pointer (task, NULL, NULL);
-      IDE_EXIT;
-    }
-
-  include_path = g_strdup_printf ("-I%s", stdoutstr);
-  g_task_return_pointer (task, include_path, g_free);
-
-  IDE_EXIT;
-}
-
-static void
-ide_makecache_discover_llvm_flags_async (IdeMakecache        *self,
-                                         GCancellable        *cancellable,
-                                         GAsyncReadyCallback  callback,
-                                         gpointer             user_data)
-{
-  g_autoptr(GTask) task = NULL;
-
-  IDE_ENTRY;
-
-  g_return_if_fail (IDE_IS_MAKECACHE (self));
-  g_return_if_fail (!cancellable || G_IS_CANCELLABLE (cancellable));
-
-  task = g_task_new (self, cancellable, callback, user_data);
-
-  ide_thread_pool_push_task (IDE_THREAD_POOL_COMPILER,
-                             task,
-                             ide_makecache_discover_llvm_flags_worker);
-
-  IDE_EXIT;
-}
-
-static gchar *
-ide_makecache_discover_llvm_flags_finish (IdeMakecache  *self,
-                                          GAsyncResult  *result,
-                                          GError       **error)
-{
-  GTask *task = (GTask *)result;
-  gchar *ret;
-
-  IDE_ENTRY;
-
-  g_assert (IDE_IS_MAKECACHE (self));
-  g_assert (G_IS_TASK (task));
-
-  ret = g_task_propagate_pointer (task, error);
-
-  IDE_RETURN (ret);
-}
 
 static gboolean
 is_target_interesting (const gchar *target)
@@ -796,8 +703,6 @@ ide_makecache_parse_c_cxx (IdeMakecache *self,
       return;
     }
 
-  g_ptr_array_add (ret, g_strdup (self->llvm_flags));
-
   for (i = 0; i < argc; i++)
     {
       const gchar *flag = argv [i];
@@ -1335,13 +1240,7 @@ ide_makecache_get_file_flags__get_targets_cb (GObject      *object,
     {
       if (file_is_clangable (lookup->file))
         {
-          gchar **ret;
-
-          ret = g_new0 (gchar *, 2);
-          ret [0] = g_strdup (self->llvm_flags);
-          ret [1] = NULL;
-
-          g_task_return_pointer (task, ret, (GDestroyNotify)g_strfreev);
+          g_task_return_pointer (task, g_new0 (gchar **, 1), (GDestroyNotify)g_strfreev);
           IDE_EXIT;
         }
 
@@ -1414,7 +1313,6 @@ ide_makecache_finalize (GObject *object)
   g_clear_pointer (&self->mapped, g_mapped_file_unref);
   g_clear_object (&self->file_targets_cache);
   g_clear_object (&self->file_flags_cache);
-  g_clear_pointer (&self->llvm_flags, g_free);
   g_clear_pointer (&self->build_targets, g_ptr_array_unref);
 
   G_OBJECT_CLASS (ide_makecache_parent_class)->finalize (object);
@@ -1519,31 +1417,6 @@ ide_makecache_get_makefile (IdeMakecache *self)
   return self->makefile;
 }
 
-static void
-ide_makecache__discover_llvm_flags_cb (GObject      *object,
-                                       GAsyncResult *result,
-                                       gpointer      user_data)
-{
-  IdeMakecache *self = (IdeMakecache *)object;
-  g_autoptr(GTask) task = user_data;
-  gchar *flags;
-  GError *error = NULL;
-
-  flags = ide_makecache_discover_llvm_flags_finish (self, result, &error);
-
-  if (error)
-    {
-      g_task_return_error (task, error);
-      return;
-    }
-
-  self->llvm_flags = flags;
-
-  ide_thread_pool_push_task (IDE_THREAD_POOL_COMPILER,
-                             task,
-                             ide_makecache_new_worker);
-}
-
 void
 ide_makecache_new_for_makefile_async (IdeContext          *context,
                                       GFile               *makefile,
@@ -1573,11 +1446,11 @@ ide_makecache_new_for_makefile_async (IdeContext          *context,
                        NULL);
 
   task = g_task_new (self, cancellable, callback, user_data);
+  g_task_set_source_tag (task, ide_makecache_new_for_makefile_async);
 
-  ide_makecache_discover_llvm_flags_async (self,
-                                           cancellable,
-                                           ide_makecache__discover_llvm_flags_cb,
-                                           g_object_ref (task));
+  ide_thread_pool_push_task (IDE_THREAD_POOL_COMPILER,
+                             task,
+                             ide_makecache_new_worker);
 
   IDE_EXIT;
 }
diff --git a/plugins/clang/ide-clang-service.c b/plugins/clang/ide-clang-service.c
index 486a731..f225c62 100644
--- a/plugins/clang/ide-clang-service.c
+++ b/plugins/clang/ide-clang-service.c
@@ -190,6 +190,60 @@ clear_unsaved_file (gpointer data)
   g_free ((gchar *)uf->Filename);
 }
 
+static const gchar *
+discover_llvm_flags (void)
+{
+  static const gchar *llvm_flags;
+  g_autoptr(GSubprocess) subprocess = NULL;
+  g_autofree gchar *stdoutstr = NULL;
+  g_autoptr(GError) error = NULL;
+  gchar *tmp;
+
+  IDE_ENTRY;
+
+  if G_LIKELY (llvm_flags != NULL)
+    IDE_RETURN (llvm_flags);
+
+  /* XXX:
+   *
+   * When we make this support clang in other runtimes, we can use
+   * the runtime to spawn the process.
+   */
+
+  IDE_TRACE_MSG ("Spawning 'clang -print-file-name=include'");
+
+  subprocess = g_subprocess_new (G_SUBPROCESS_FLAGS_STDOUT_PIPE,
+                                 &error,
+                                 "clang",
+                                 "-print-file-name=include",
+                                 NULL);
+
+  if (!subprocess)
+    {
+      g_warning ("%s\n", error->message);
+      IDE_RETURN (NULL);
+    }
+
+  if (!g_subprocess_communicate_utf8 (subprocess, NULL, NULL, &stdoutstr, NULL, &error))
+    {
+      g_warning ("%s\n", error->message);
+      IDE_RETURN (NULL);
+    }
+
+  g_strstrip (stdoutstr);
+
+  IDE_TRACE_MSG ("Clang include path result: %s", stdoutstr);
+
+  if (g_str_equal (stdoutstr, "include"))
+    IDE_RETURN (NULL);
+
+  tmp = g_strdup_printf ("-I%s", stdoutstr);
+  llvm_flags = g_intern_string (tmp);
+  g_free (tmp);
+
+  IDE_RETURN (llvm_flags);
+}
+
 static void
 ide_clang_service_parse_worker (GTask        *task,
                                 gpointer      source_object,
@@ -203,10 +257,10 @@ ide_clang_service_parse_worker (GTask        *task,
   CXTranslationUnit tu = NULL;
   ParseRequest *request = task_data;
   IdeContext *context;
-  const gchar * const *argv;
+  g_autoptr(GPtrArray) built_argv = NULL;
   GFile *gfile;
-  gsize argc = 0;
   const gchar *detail_error = NULL;
+  const gchar *llvm_flags;
   enum CXErrorCode code;
   GArray *ar = NULL;
   gsize i;
@@ -238,14 +292,23 @@ ide_clang_service_parse_worker (GTask        *task,
       g_array_append_val (ar, uf);
     }
 
-  argv = (const gchar * const *)request->command_line_args;
-  argc = argv ? g_strv_length (request->command_line_args) : 0;
+  /*
+   * Synthesize new argv array for Clang withour discovered llvm flags
+   * included. Add a guard NULL just for extra safety.
+   */
+  built_argv = g_ptr_array_new ();
+  if (NULL != (llvm_flags = discover_llvm_flags ()))
+    g_ptr_array_add (built_argv, (gchar *)llvm_flags);
+  for (i = 0; request->command_line_args[i] != NULL; i++)
+    g_ptr_array_add (built_argv, request->command_line_args[i]);
+  g_ptr_array_add (built_argv, NULL);
 
   EGG_COUNTER_INC (ParseAttempts);
   code = clang_parseTranslationUnit2 (request->index,
                                       request->source_filename,
-                                      argv, argc,
-                                      (struct CXUnsavedFile *)(void *)ar->data,
+                                      (const gchar * const *)built_argv->pdata,
+                                      built_argv->len - 1,
+                                      (struct CXUnsavedFile *)(gpointer)ar->data,
                                       ar->len,
                                       request->options,
                                       &tu);