configure: Add switch for clang's "source-based" code coverage feature

This adds instrumentation to the binaries. At the end of their
execution, these will then write a file containing information which code
was executed. This can be used for code coverage analysis.

[ChangeLog][QtCore][configure] Add switch "-coverage source-based" to
enable clang's "source-based" code coverage feature. This can be used
for code coverage analysis.

Change-Id: If31c6849aa797ff8820e041e85a492a14e2f1a6b
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

config_help.txt

@@ -137,8 +137,10 @@ Build options:
                          for example, -sanitize address cannot be combined with
                          -sanitize thread.
 
-  -coverage {trace-pc-guard}
+  -coverage {trace-pc-guard|source-based}
-                         Add code coverage instrumentation (Clang only)
+                         Specify the 'trace-pc-guard' coverage instrumentation for
+                         sanitizers or generate instrumented code to collect execution
+                         counts and enable code coverage analysis, respectively. (Clang only)
 
   -c++std <edition> .... Select C++ standard <edition> [c++2a/c++17/c++14/c++11]
                          (Not supported with MSVC 2015)

configure.json

@@ -916,9 +916,14 @@
             "autoDetect": false,
             "output": [ "publicConfig" ]
         },
+        "coverage_source_based": {
+            "label": "source-based",
+            "autoDetect": false,
+            "output": [ "publicConfig" ]
+        },
         "coverage": {
             "label": "Code Coverage Instrumentation",
-            "condition": "features.coverage_trace_pc_guard",
+            "condition": "features.coverage_trace_pc_guard || features.coverage_source_based",
             "output": [ "publicConfig" ]
         },
         "GNUmake": {
@@ -1612,7 +1617,7 @@ Configure with '-qreal float' to create a build that is binary-compatible with 5
                 {
                     "message": "Code Coverage Instrumentation",
                     "type": "firstAvailableFeature",
-                    "args": "coverage_trace_pc_guard",
+                    "args": "coverage_trace_pc_guard coverage_source_based",
                     "condition": "features.coverage"
                 },
                 {

configure.pri

@@ -72,7 +72,9 @@ defineTest(qtConfCommandline_coverage) {
     !contains(val, "^-.*"):!isEmpty(val) {
         equals(val, "trace-pc-guard") {
             qtConfCommandlineSetInput("coverage_trace_pc_guard", "yes")
-        } else {
+        } else: equals(val, "source-based") {
+            qtConfCommandlineSetInput("coverage_source_based", "yes")
+        } else: {
             qtConfAddError("Invalid argument $$val to command line parameter $$arg")
         }
     } else {

mkspecs/common/clang.conf

@@ -54,3 +54,7 @@ QMAKE_RANLIB_LTCG       = true      # No need to run, since llvm-ar has "s"
 QMAKE_CFLAGS_COVERAGE_TRACE_PC_GUARD   = -fsanitize-coverage=trace-pc-guard
 QMAKE_CXXFLAGS_COVERAGE_TRACE_PC_GUARD = -fsanitize-coverage=trace-pc-guard
 QMAKE_LFLAGS_COVERAGE_TRACE_PC_GUARD   = -fsanitize-coverage=trace-pc-guard
+
+QMAKE_CFLAGS_COVERAGE_SOURCE_BASED   = -fprofile-instr-generate -fcoverage-mapping
+QMAKE_CXXFLAGS_COVERAGE_SOURCE_BASED = -fprofile-instr-generate -fcoverage-mapping
+QMAKE_LFLAGS_COVERAGE_SOURCE_BASED   = -fprofile-instr-generate -fcoverage-mapping

mkspecs/features/coverage.prf

@@ -5,3 +5,9 @@ coverage_trace_pc_guard {
     QMAKE_CXXFLAGS += $$QMAKE_CXXFLAGS_COVERAGE_TRACE_PC_GUARD
     QMAKE_LFLAGS   += $$QMAKE_LFLAGS_COVERAGE_TRACE_PC_GUARD
 }
+
+coverage_source_based {
+    QMAKE_CFLAGS   += $$QMAKE_CFLAGS_COVERAGE_SOURCE_BASED
+    QMAKE_CXXFLAGS += $$QMAKE_CXXFLAGS_COVERAGE_SOURCE_BASED
+    QMAKE_LFLAGS   += $$QMAKE_LFLAGS_COVERAGE_SOURCE_BASED
+}