fix order of libraries in gcc link command line

Array.uniqueConcat cannot be used to remove duplicates, because the
right-most duplicates are removed. To keep the dependencies ordered
correctly, we must remove the left-most duplicates instead.

Task-number: QBS-503
Change-Id: I5a2834905f650e0921bc42f9cffe15b71128ff7e
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>

2 files changed, 22 insertions, 4 deletions

diff --git a/share/qbs/modules/cpp/GenericGCC.qbs b/share/qbs/modules/cpp/GenericGCC.qbs
index 0cbb2b982..a881159d9 100644
--- a/share/qbs/modules/cpp/GenericGCC.qbs
+++ b/share/qbs/modules/cpp/GenericGCC.qbs
@@ -102,10 +102,11 @@ CppModule {
                 for (var i in inputs.dynamiclibrary_copy) {
                     var lib = inputs.dynamiclibrary_copy[i]
                     var impliedLibs = ModUtils.moduleProperties(lib, 'transitiveSOs')
-                    var libsToAdd = impliedLibs.uniqueConcat([lib.fileName]);
-                    result = result.uniqueConcat(libsToAdd);
+                    var libsToAdd = [lib.fileName].concat(impliedLibs);
+                    result = result.concat(libsToAdd);
                 }
-                return result
+                result = Gcc.concatLibs([], result);
+                return result;
             }
         }
 
@@ -218,7 +219,7 @@ CppModule {
                     var lib = inputs.staticlibrary[i]
                     result.push(lib.fileName)
                     var impliedLibs = ModUtils.moduleProperties(lib, 'staticLibraries')
-                    result = result.uniqueConcat(impliedLibs);
+                    result = Gcc.concatLibs(result, impliedLibs);
                 }
                 return result
             }
diff --git a/share/qbs/modules/cpp/gcc.js b/share/qbs/modules/cpp/gcc.js
index 604e20eec..a44465132 100644
--- a/share/qbs/modules/cpp/gcc.js
+++ b/share/qbs/modules/cpp/gcc.js
@@ -343,3 +343,20 @@ function prepareCompiler(project, product, inputs, outputs, input, output)
     cmd.responseFileUsagePrefix = '@';
     return cmd;
 }
+
+// Concatenates two arrays of library names and preserves the dependency order that ld needs.
+function concatLibs(libs, deplibs)
+{
+    var r = [];
+    var s = {};
+    function f(e)
+    {
+        if (!s[e]) {
+            s[e] = true;
+            r.unshift(e);
+        }
+    }
+    deplibs.forEach(f);
+    libs.forEach(f);
+    return r;
+}