Fix backtrace on non-linux systems

On BSD systems backtrace lies in libexecinfo. Use
FindBacktrace from CMake to be able to resolve
backtrace on more unixes than linux.

Change-Id: Ie14fd1727d2da03645fc2d6de10c0217baabad6b
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

cmake/FindWrapBacktrace.cmake

@@ -0,0 +1,17 @@
+if(TARGET WrapBacktrace::WrapBacktrace)
+    set(WrapBacktrace_FOUND ON)
+    return()
+endif()
+
+find_package(Backtrace)
+
+if(Backtrace_FOUND)
+    add_library(WrapBacktrace::WrapBacktrace INTERFACE IMPORTED)
+    target_link_libraries(WrapBacktrace::WrapBacktrace
+                          INTERFACE ${Backtrace_LIBRARY})
+    target_include_directories(WrapBacktrace::WrapBacktrace
+                               INTERFACE ${Backtrace_INCLUDE_DIR})
+    set(WrapBacktrace_FOUND ON)
+else()
+    set(WrapBacktrace_FOUND OFF)
+endif()

src/corelib/CMakeLists.txt

@@ -729,6 +729,11 @@ qt_internal_extend_target(Core CONDITION QT_FEATURE_commandlineparser
         tools/qcommandlineparser.cpp tools/qcommandlineparser.h
 )
 
+qt_internal_extend_target(Core CONDITION QT_FEATURE_backtrace
+    LIBRARIES
+        WrapBacktrace::WrapBacktrace
+)
+
 qt_internal_extend_target(Core CONDITION QT_FEATURE_system_doubleconversion
     LIBRARIES
         WrapDoubleConversion::WrapDoubleConversion

src/corelib/configure.cmake

@@ -14,6 +14,9 @@ set_property(CACHE INPUT_libb2 PROPERTY STRINGS undefined no qt system)
 
 #### Libraries
 
+if((UNIX) OR QT_FIND_ALL_PACKAGES_ALWAYS)
+    qt_find_package(WrapBacktrace PROVIDED_TARGETS WrapBacktrace::WrapBacktrace MODULE_NAME core QMAKE_LIB backtrace)
+endif()
 qt_find_package(WrapDoubleConversion PROVIDED_TARGETS WrapDoubleConversion::WrapDoubleConversion MODULE_NAME core QMAKE_LIB doubleconversion)
 qt_find_package(GLIB2 PROVIDED_TARGETS GLIB2::GLIB2 MODULE_NAME core QMAKE_LIB glib)
 qt_find_package(ICU COMPONENTS i18n uc data PROVIDED_TARGETS ICU::i18n ICU::uc ICU::data MODULE_NAME core QMAKE_LIB icu)
@@ -674,6 +677,10 @@ qt_feature("regularexpression" PUBLIC
     CONDITION QT_FEATURE_system_pcre2 OR QT_FEATURE_pcre2
 )
 qt_feature_definition("regularexpression" "QT_NO_REGULAREXPRESSION" NEGATE VALUE "1")
+qt_feature("backtrace" PRIVATE
+    LABEL "backtrace"
+    CONDITION UNIX AND QT_FEATURE_regularexpression AND WrapBacktrace_FOUND
+)
 qt_feature("sharedmemory" PUBLIC
     SECTION "Kernel"
     LABEL "QSharedMemory"
@@ -909,6 +916,7 @@ qt_feature("cborstreamwriter" PUBLIC
     PURPOSE "Provides support for writing the CBOR binary format."
 )
 qt_configure_add_summary_section(NAME "Qt Core")
+qt_configure_add_summary_entry(ARGS "backtrace")
 qt_configure_add_summary_entry(ARGS "doubleconversion")
 qt_configure_add_summary_entry(ARGS "system-doubleconversion")
 qt_configure_add_summary_entry(ARGS "glib")

src/corelib/configure.json

@@ -22,6 +22,17 @@
     },
 
     "libraries": {
+        "backtrace": {
+            "label": "backtrace",
+            "test": {
+                "main":
+                    [ "void *buffer[100];",
+                      "int nptrs = backtrace(buffer, 100);"
+                    ]
+            },
+            "headers": "execinfo.h",
+            "sources": [ "-lexecinfo" ]
+        },
         "doubleconversion": {
             "label": "DoubleConversion",
             "test": {
@@ -718,6 +729,11 @@
             "condition": "features.system-pcre2 || features.pcre2",
             "output": [ "publicFeature", "feature" ]
         },
+        "backtrace": {
+            "label": "backtrace",
+            "condition": "config.unix && features.regularexpression && libs.backtrace",
+            "output": [ "privateFeature" ]
+        },
         "sharedmemory": {
             "label": "QSharedMemory",
             "purpose": "Provides access to a shared memory segment.",
@@ -1013,6 +1029,7 @@ Note that this is required for plugin loading. Qt GUI needs QPA plugins for basi
         {
             "section": "Qt Core",
             "entries": [
+                "backtrace",
                 "doubleconversion",
                 "system-doubleconversion",
                 "glib",

util/cmake/helper.py

@@ -402,6 +402,7 @@ _qt_library_map = [
 _library_map = [
     # 3rd party:
     LibraryMapping("atspi", "ATSPI2", "PkgConfig::ATSPI2"),
+    LibraryMapping("backtrace", "WrapBacktrace", "WrapBacktrace::WrapBacktrace", emit_if="config.unix"),
     LibraryMapping("bluez", "BlueZ", "PkgConfig::BlueZ"),
     LibraryMapping("brotli", "WrapBrotli", "WrapBrotli::WrapBrotliDec"),
     LibraryMapping("corewlan", None, None),