CppTools: Do not use -isystem for header paths in the repository

Clang uses mmap for system headers. This locks the header files on Windows.

If the project file is not in the root directory of the repository, and it
uses header files that are outside its directory, but in the repository,
Git operations like checkout, rebase etc. can fail because the header files
are locked.

Change-Id: If8a258234479fc70ca0a8384bf24c68d767dbeaa
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

1 files changed, 12 insertions, 3 deletions

diff --git a/src/plugins/cpptools/compileroptionsbuilder.cpp b/src/plugins/cpptools/compileroptionsbuilder.cpp
index a2ed615894..1188075a2a 100644
--- a/src/plugins/cpptools/compileroptionsbuilder.cpp
+++ b/src/plugins/cpptools/compileroptionsbuilder.cpp
@@ -26,6 +26,7 @@
 #include "compileroptionsbuilder.h"
 
 #include <coreplugin/icore.h>
+#include <coreplugin/vcsmanager.h>
 
 #include <projectexplorer/project.h>
 #include <projectexplorer/projectexplorerconstants.h>
@@ -137,7 +138,12 @@ static Utils::FileName projectTopLevelDirectory(const ProjectPart &projectPart)
 {
     if (!projectPart.project)
         return Utils::FileName();
-    return projectPart.project->projectDirectory();
+    const Utils::FileName result = projectPart.project->projectDirectory();
+    const Utils::FileName vcsTopLevel = Utils::FileName::fromString(
+                Core::VcsManager::findTopLevelForDirectory(result.toString()));
+    if (result.isChildOf(vcsTopLevel))
+        return vcsTopLevel;
+    return result;
 }
 
 void CompilerOptionsBuilder::addHeaderPathOptions()
@@ -165,10 +171,13 @@ void CompilerOptionsBuilder::addHeaderPathOptions()
             // intentional fall-through:
         case HeaderPath::IncludePath:
             path = absoluteDirectory(headerPath.path);
-            if (path == projectDirectory || path.isChildOf(projectDirectory))
+            if (projectDirectory.isEmpty()
+                    || path == projectDirectory
+                    || path.isChildOf(projectDirectory)) {
                 prefix = defaultPrefix;
-            else
+            } else {
                 prefix = SYSTEM_INCLUDE_PREFIX;
+            }
             break;
         }