Blackberry mkspecs: Refine compiler options

stack-protector-strong gives performance benefits over
stack-protector-all and is still checking more than -stack-protector,
so seems to be a good middle way and we want to use it when it is
there.

The -shared option for the compiler (not the linker) prevents a
RIM internal version of qcc from forcing -fPIE, and should not harm
in general when set.

In addition, add a method "compilerSupportsFlag" for Windows as is
present in the Unix configure script.

Change-Id: Iba300e9cb82f34043e7b36f8e45287a1aed2a1a5
Original-patch-by: Greg Bentz
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

2 files changed, 33 insertions, 0 deletions

diff --git a/tools/configure/configureapp.cpp b/tools/configure/configureapp.cpp
index 4fce6f21d7..d1244f0f59 100644
--- a/tools/configure/configureapp.cpp
+++ b/tools/configure/configureapp.cpp
@@ -1504,6 +1504,8 @@ void Configure::applySpecSpecifics()
         dictionary[ "QT_ICONV" ]            = "no";
 
         dictionary["DECORATIONS"]           = "default windows styled";
+    } else if ((platform() == QNX) || (platform() == BLACKBERRY)) {
+        dictionary["STACK_PROTECTOR_STRONG"] = "auto";
     }
 }
 
@@ -2041,6 +2043,8 @@ bool Configure::checkAvailability(const QString &part)
         available = tryCompileProject("unix/iconv") || tryCompileProject("unix/gnu-libiconv");
     } else if (part == "CUPS") {
         available = (platform() != WINDOWS) && (platform() != WINDOWS_CE) && tryCompileProject("unix/cups");
+    } else if (part == "STACK_PROTECTOR_STRONG") {
+        available = (platform() == QNX || platform() == BLACKBERRY) && compilerSupportsFlag("qcc -fstack-protector-strong");
     }
 
     return available;
@@ -2153,6 +2157,10 @@ void Configure::autoDetection()
     if (dictionary["QT_CUPS"] == "auto")
         dictionary["QT_CUPS"] = checkAvailability("CUPS") ? "yes" : "no";
 
+    // Detection of -fstack-protector-strong support
+    if (dictionary["STACK_PROTECTOR_STRONG"] == "auto")
+        dictionary["STACK_PROTECTOR_STRONG"] = checkAvailability("STACK_PROTECTOR_STRONG") ? "yes" : "no";
+
     // Mark all unknown "auto" to the default value..
     for (QMap<QString,QString>::iterator i = dictionary.begin(); i != dictionary.end(); ++i) {
         if (i.value() == "auto")
@@ -2511,6 +2519,9 @@ void Configure::generateOutputVars()
     if (dictionary["QT_GLIB"] == "yes")
         qtConfig += "glib";
 
+    if (dictionary["STACK_PROTECTOR_STRONG"] == "yes")
+        qtConfig += "stack-protector-strong";
+
     // We currently have no switch for QtConcurrent, so add it unconditionally.
     qtConfig += "concurrent";
 
@@ -2872,6 +2883,27 @@ bool Configure::tryCompileProject(const QString &projectPath, const QString &ext
     return code == 0;
 }
 
+bool Configure::compilerSupportsFlag(const QString &compilerAndArgs)
+{
+    QFile file("conftest.cpp");
+    if (!file.open(QIODevice::WriteOnly | QIODevice::Text)) {
+        cout << "could not open temp file for writing" << endl;
+        return false;
+    }
+    if (!file.write("int main() { return 0; }\r\n")) {
+        cout << "could not write to temp file" << endl;
+        return false;
+    }
+    file.close();
+    // compilerAndArgs contains compiler because there is no way to query it
+    QString command = compilerAndArgs + " -o conftest-out.o conftest.cpp";
+    int code = 0;
+    QString output = Environment::execute(command, &code);
+    file.remove();
+    QFile::remove("conftest-out.o");
+    return code == 0;
+}
+
 void Configure::generateQConfigPri()
 {
     // Generate qconfig.pri
diff --git a/tools/configure/configureapp.h b/tools/configure/configureapp.h
index 3261f4f80d..8cae9da4f8 100644
--- a/tools/configure/configureapp.h
+++ b/tools/configure/configureapp.h
@@ -175,6 +175,7 @@ private:
 #endif
 
     bool tryCompileProject(const QString &projectPath, const QString &extraOptions = QString());
+    bool compilerSupportsFlag(const QString &compilerAndArgs);
 
     void desc(const char *description, int startingAt = 0, int wrapIndent = 0);
     void desc(const char *option, const char *description, bool skipIndent = false, char fillChar = '.');