qconfig.cpp: use qOffsetStringArray

It's been there for ages, we may as well use it and remove unnecessary
complexity from CMake.

Pick-to: 6.2
Change-Id: I2bbf422288924c198645fffd16a9742567a7e4af
Reviewed-by: Thiago Macieira <[email protected]>
Reviewed-by: Alexey Edelev <[email protected]>

4 files changed, 35 insertions, 44 deletions

diff --git a/cmake/QtQmakeHelpers.cmake b/cmake/QtQmakeHelpers.cmake
index 7c5d21ce78c..9ad84da5ee3 100644
--- a/cmake/QtQmakeHelpers.cmake
+++ b/cmake/QtQmakeHelpers.cmake
@@ -13,35 +13,22 @@ function(qt_to_qmake_path_list out_var)
     set("${out_var}" "${result}" PARENT_SCOPE)
 endfunction()
 
-macro(qt_add_string_to_qconfig_cpp str)
-    string(LENGTH "${str}" length)
-    string(APPEND QT_CONFIG_STRS "    \"${str}\\0\"\n")
-    string(APPEND QT_CONFIG_STR_OFFSETS "    ${QT_CONFIG_STR_OFFSET},\n")
-    math(EXPR QT_CONFIG_STR_OFFSET "${QT_CONFIG_STR_OFFSET}+${length}+1")
-endmacro()
 
 function(qt_generate_qconfig_cpp in_file out_file)
-    set(QT_CONFIG_STR_OFFSET "0")
-    set(QT_CONFIG_STR_OFFSETS "")
     set(QT_CONFIG_STRS "")
 
-    # Start first part.
-    qt_add_string_to_qconfig_cpp("${INSTALL_DOCDIR}")
-    qt_add_string_to_qconfig_cpp("${INSTALL_INCLUDEDIR}")
-    qt_add_string_to_qconfig_cpp("${INSTALL_LIBDIR}")
-    qt_add_string_to_qconfig_cpp("${INSTALL_LIBEXECDIR}")
-    qt_add_string_to_qconfig_cpp("${INSTALL_BINDIR}")
-    qt_add_string_to_qconfig_cpp("${INSTALL_PLUGINSDIR}")
-    qt_add_string_to_qconfig_cpp("${INSTALL_QMLDIR}")
-    qt_add_string_to_qconfig_cpp("${INSTALL_ARCHDATADIR}")
-    qt_add_string_to_qconfig_cpp("${INSTALL_DATADIR}")
-    qt_add_string_to_qconfig_cpp("${INSTALL_TRANSLATIONSDIR}")
-    qt_add_string_to_qconfig_cpp("${INSTALL_EXAMPLESDIR}")
-    qt_add_string_to_qconfig_cpp("${INSTALL_TESTSDIR}")
-
-    # Save first part.
-    set(QT_CONFIG_STR_OFFSETS_FIRST "${QT_CONFIG_STR_OFFSETS}")
-    set(QT_CONFIG_STRS_FIRST "${QT_CONFIG_STRS}")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_DOCDIR}\",\n")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_INCLUDEDIR}\",\n")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_LIBDIR}\",\n")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_LIBEXECDIR}\",\n")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_BINDIR}\",\n")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_PLUGINSDIR}\",\n")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_QMLDIR}\",\n")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_ARCHDATADIR}\",\n")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_DATADIR}\",\n")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_TRANSLATIONSDIR}\",\n")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_EXAMPLESDIR}\",\n")
+    string(APPEND QT_CONFIG_STRS "    \"${INSTALL_TESTSDIR}\"")
 
     # Settings path / sysconf dir.
     set(QT_SYS_CONF_DIR "${INSTALL_SYSCONFDIR}")
diff --git a/src/corelib/global/qconfig.cpp.in b/src/corelib/global/qconfig.cpp.in
index f6ce3355997..7c79d9073dd 100644
--- a/src/corelib/global/qconfig.cpp.in
+++ b/src/corelib/global/qconfig.cpp.in
@@ -5,19 +5,16 @@
  *
  * - QLibraryInfo::LibraryPath enum in qtbase/src/corelib/global/qlibraryinfo.h
  * - qtConfEntries in qtbase/src/corelib/global/qlibraryinfo.cpp
- *
- * The reason for this is pointer mathematics in the QLibraryInfo implementation when iterating
- * qt_configure_strs. Also qtConfEntries are strongly bound to QLibraryInfo::LibraryPath.
  */
+#include "private/qoffsetstringarray_p.h"
 
 /* Installation Info */
 static const char qt_configure_prefix_path_str  [12+256] = "qt_prfxpath=@QT_CONFIGURE_PREFIX_PATH_STR@";
-static const short qt_configure_str_offsets[] = {
-@QT_CONFIG_STR_OFFSETS_FIRST@
-};
-static const char qt_configure_strs[] =
-@QT_CONFIG_STRS_FIRST@
-;
+
+static constexpr auto qt_configure_strs = QT_PREPEND_NAMESPACE(qOffsetStringArray)(
+@QT_CONFIG_STRS@
+);
+
 #define QT_CONFIGURE_SETTINGS_PATH "@QT_SYS_CONF_DIR@"
 #define QT_CONFIGURE_LIBLOCATION_TO_PREFIX_PATH "@QT_CONFIGURE_LIBLOCATION_TO_PREFIX_PATH@"
 #define QT_CONFIGURE_PREFIX_PATH qt_configure_prefix_path_str + 12
diff --git a/src/corelib/global/qlibraryinfo.cpp b/src/corelib/global/qlibraryinfo.cpp
index 18a429fb6dc..a2bf7599fed 100644
--- a/src/corelib/global/qlibraryinfo.cpp
+++ b/src/corelib/global/qlibraryinfo.cpp
@@ -1,7 +1,7 @@
 /****************************************************************************
 **
-** Copyright (C) 2020 The Qt Company Ltd.
-** Copyright (C) 2016 Intel Corporation.
+** Copyright (C) 2021 The Qt Company Ltd.
+** Copyright (C) 2021 Intel Corporation.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -51,14 +51,13 @@
 #include "qcoreapplication.h"
 
 #include "private/qglobal_p.h"
+#include "archdetect.cpp"
 #include "qconfig.cpp"
 
 #ifdef Q_OS_DARWIN
 #  include "private/qcore_mac_p.h"
 #endif // Q_OS_DARWIN
 
-#include "archdetect.cpp"
-
 #if QT_CONFIG(relocatable) && QT_CONFIG(dlopen) && !QT_CONFIG(framework)
 #    include <dlfcn.h>
 #endif
@@ -454,7 +453,7 @@ static QString getRelocatablePrefix()
         // executable within the QT_HOST_BIN directory. We're detecting the latter case by checking
         // whether there's an import library corresponding to our QtCore DLL in PREFIX/lib.
         const QString libdir = QString::fromLocal8Bit(
-            qt_configure_strs + qt_configure_str_offsets[QLibraryInfo::LibrariesPath - 1]);
+            qt_configure_strs[QLibraryInfo::LibrariesPath - 1]);
         const QLatin1Char slash('/');
 #if defined(Q_CC_MINGW)
         const QString implibPrefix = QStringLiteral("lib");
@@ -486,7 +485,7 @@ static QString getRelocatablePrefix()
     // See "Hardware capabilities" in the ld.so documentation and the Qt 5.3.0
     // changelog regarding SSE2 support.
     const QString libdir = QString::fromLocal8Bit(
-        qt_configure_strs + qt_configure_str_offsets[QLibraryInfo::LibrariesPath - 1]);
+        qt_configure_strs[QLibraryInfo::LibrariesPath - 1]);
     QDir prefixDir(prefixPath);
     while (!prefixDir.exists(libdir)) {
         prefixDir.cdUp();
@@ -596,8 +595,8 @@ QString QLibraryInfo::path(LibraryPath p)
         const char * volatile path = nullptr;
         if (loc == PrefixPath) {
             ret = getPrefix();
-        } else if (unsigned(loc) <= sizeof(qt_configure_str_offsets)/sizeof(qt_configure_str_offsets[0])) {
-            path = qt_configure_strs + qt_configure_str_offsets[loc - 1];
+        } else if (int(loc) <= qt_configure_strs.count()) {
+            path = qt_configure_strs[loc - 1];
 #ifndef Q_OS_WIN // On Windows we use the registry
         } else if (loc == SettingsPath) {
             path = QT_CONFIGURE_SETTINGS_PATH;
@@ -691,6 +690,7 @@ QT_END_NAMESPACE
 
 #include "private/qcoreapplication_p.h"
 
+QT_WARNING_DISABLE_GCC("-Wformat-overflow")
 QT_WARNING_DISABLE_GCC("-Wattributes")
 QT_WARNING_DISABLE_CLANG("-Wattributes")
 QT_WARNING_DISABLE_INTEL(2621)
@@ -738,8 +738,8 @@ void qt_core_boilerplate()
            "Library path:        %s\n"
            "Plugin path:         %s\n",
            qt_configure_prefix_path_str + 12,
-           qt_configure_strs + qt_configure_str_offsets[QT_PREPEND_NAMESPACE(QLibraryInfo)::LibrariesPath - 1],
-           qt_configure_strs + qt_configure_str_offsets[QT_PREPEND_NAMESPACE(QLibraryInfo)::PluginsPath - 1]);
+           qt_configure_strs[QT_PREPEND_NAMESPACE(QLibraryInfo)::LibrariesPath - 1],
+           qt_configure_strs[QT_PREPEND_NAMESPACE(QLibraryInfo)::PluginsPath - 1]);
 
     QT_PREPEND_NAMESPACE(qDumpCPUFeatures)();
 
diff --git a/src/corelib/tools/qoffsetstringarray_p.h b/src/corelib/tools/qoffsetstringarray_p.h
index 6e0cb1f30bd..607f13d6623 100644
--- a/src/corelib/tools/qoffsetstringarray_p.h
+++ b/src/corelib/tools/qoffsetstringarray_p.h
@@ -63,6 +63,12 @@ class tst_QOffsetStringArray;
 
 QT_BEGIN_NAMESPACE
 
+QT_WARNING_PUSH
+#if defined(Q_CC_GNU) && Q_CC_GNU >= 1100
+// we usually don't overread, but GCC has a false positive
+QT_WARNING_DISABLE_GCC("-Wstringop-overread")
+#endif
+
 
 template <typename StaticString, typename OffsetList>
 class QOffsetStringArray
@@ -172,6 +178,7 @@ constexpr auto qOffsetStringArray(const char (&...strings)[Nx]) noexcept
     return QtPrivate::qOffsetStringArray(extractString, QtPrivate::StaticString(strings)...);
 }
 
+QT_WARNING_POP
 QT_END_NAMESPACE
 
 #endif // QOFFSETSTRINGARRAY_P_H