Help compiler with branch prediction.

Mark error checks in potentially performance-sensitive
contexts with Q_UNLIKELY. Actual benefits unknown,
but it cannot hurt.

Change-Id: If3d2375965e6342b5d7a0b46ad2c8a41fd3567d0
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>

21 files changed, 81 insertions, 81 deletions

diff --git a/src/lib/buildgraph/command.cpp b/src/lib/buildgraph/command.cpp
index 64b4c57e3..c1e28319a 100644
--- a/src/lib/buildgraph/command.cpp
+++ b/src/lib/buildgraph/command.cpp
@@ -95,7 +95,7 @@ static QScriptValue js_CommandBase(QScriptContext *context, QScriptEngine *engin
 
 static QScriptValue js_Command(QScriptContext *context, QScriptEngine *engine)
 {
-    if (context->argumentCount() != 2) {
+    if (Q_UNLIKELY(context->argumentCount() != 2)) {
         return context->throwError(QScriptContext::SyntaxError,
                                    "Command c'tor expects 2 arguments");
     }
@@ -213,7 +213,7 @@ void ProcessCommand::store(QDataStream &s)
 
 static QScriptValue js_JavaScriptCommand(QScriptContext *context, QScriptEngine *engine)
 {
-    if (context->argumentCount() != 0) {
+    if (Q_UNLIKELY(context->argumentCount() != 0)) {
         return context->throwError(QScriptContext::SyntaxError,
                                    "JavaScriptCommand c'tor doesn't take arguments.");
     }
diff --git a/src/lib/buildgraph/cycledetector.cpp b/src/lib/buildgraph/cycledetector.cpp
index 1e9dcdb9d..3e39b70c9 100644
--- a/src/lib/buildgraph/cycledetector.cpp
+++ b/src/lib/buildgraph/cycledetector.cpp
@@ -53,7 +53,7 @@ void CycleDetector::visitProject(const ResolvedProjectConstPtr &project)
 
 void CycleDetector::visitArtifact(Artifact *artifact)
 {
-    if (m_artifactsInCurrentPath.contains(artifact)) {
+    if (Q_UNLIKELY(m_artifactsInCurrentPath.contains(artifact))) {
         Error error(Tr::tr("Cycle in build graph detected."));
         foreach (const Artifact * const a, cycle(artifact))
             error.append(a->filePath());
diff --git a/src/lib/buildgraph/processcommandexecutor.cpp b/src/lib/buildgraph/processcommandexecutor.cpp
index 501b97b03..533feda26 100644
--- a/src/lib/buildgraph/processcommandexecutor.cpp
+++ b/src/lib/buildgraph/processcommandexecutor.cpp
@@ -255,7 +255,7 @@ void ProcessCommandExecutor::onProcessFinished(int exitCode)
     const bool errorOccurred = exitCode > processCommand()->maxExitCode();
     sendProcessOutput(!errorOccurred);
 
-    if (errorOccurred) {
+    if (Q_UNLIKELY(errorOccurred)) {
         emit error(Error(Tr::tr("Process failed with exit code %1.").arg(exitCode)));
         return;
     }
diff --git a/src/lib/buildgraph/projectbuilddata.cpp b/src/lib/buildgraph/projectbuilddata.cpp
index d3bd7b510..3bd8843b4 100644
--- a/src/lib/buildgraph/projectbuilddata.cpp
+++ b/src/lib/buildgraph/projectbuilddata.cpp
@@ -283,7 +283,7 @@ void BuildDataResolver::resolveProductBuildData(const ResolvedProductPtr &produc
     ArtifactsPerFileTagMap artifactsPerFileTag;
 
     foreach (ResolvedProductPtr dependency, product->dependencies) {
-        if (!dependency->enabled) {
+        if (Q_UNLIKELY(!dependency->enabled)) {
             QString msg = Tr::tr("Product '%1' depends on '%2' but '%2' is disabled.");
             throw Error(msg.arg(product->name, dependency->name));
         }
@@ -318,7 +318,7 @@ void BuildDataResolver::resolveProductBuildData(const ResolvedProductPtr &produc
         ArtifactList inputArtifacts;
         foreach (const QString &inputFileName, rtrafo->inputs) {
             Artifact *artifact = lookupArtifact(product, inputFileName);
-            if (!artifact)
+            if (Q_UNLIKELY(!artifact))
                 throw Error(QString("Can't find artifact '%0' in the list of source files.").arg(inputFileName));
             inputArtifacts += artifact;
         }
@@ -353,7 +353,7 @@ void BuildDataResolver::resolveProductBuildData(const ResolvedProductPtr &produc
         transformer->setupInputs(engine(), scope());
         transformer->setupOutputs(engine(), scope());
         transformer->createCommands(rtrafo->transform, evalContext());
-        if (transformer->commands.isEmpty())
+        if (Q_UNLIKELY(transformer->commands.isEmpty()))
             throw Error(QString("There's a transformer without commands."), rtrafo->transform->location);
     }
 
diff --git a/src/lib/buildgraph/rulesapplicator.cpp b/src/lib/buildgraph/rulesapplicator.cpp
index 16e9a8d5a..a9781d10e 100644
--- a/src/lib/buildgraph/rulesapplicator.cpp
+++ b/src/lib/buildgraph/rulesapplicator.cpp
@@ -171,7 +171,7 @@ void RulesApplicator::doApply(const ArtifactList &inputArtifacts)
         for (int i=0; i < ra->bindings.count(); ++i) {
             const RuleArtifact::Binding &binding = ra->bindings.at(i);
             scriptValue = engine()->evaluate(binding.code);
-            if (scriptValue.isError()) {
+            if (Q_UNLIKELY(scriptValue.isError())) {
                 QString msg = QLatin1String("evaluating rule binding '%1': %2");
                 throw Error(msg.arg(binding.name.join(QLatin1String(".")), scriptValue.toString()), binding.location);
             }
@@ -184,7 +184,7 @@ void RulesApplicator::doApply(const ArtifactList &inputArtifacts)
 
     m_transformer->setupOutputs(engine(), scope());
     m_transformer->createCommands(m_rule->script, evalContext());
-    if (m_transformer->commands.isEmpty())
+    if (Q_UNLIKELY(m_transformer->commands.isEmpty()))
         throw Error(QString("There's a rule without commands: %1.").arg(m_rule->toString()), m_rule->script->location);
 }
 
@@ -220,7 +220,7 @@ Artifact *RulesApplicator::createOutputArtifact(const RuleArtifactConstPtr &rule
         const ArtifactList &inputArtifacts)
 {
     QScriptValue scriptValue = engine()->evaluate(ruleArtifact->fileName);
-    if (scriptValue.isError() || engine()->hasUncaughtException())
+    if (Q_UNLIKELY(scriptValue.isError() || engine()->hasUncaughtException()))
         throw Error("Error in Rule.Artifact fileName: " + scriptValue.toString());
     QString outputPath = scriptValue.toString();
     outputPath.replace("..", "dotdot");     // don't let the output artifact "escape" its build dir
@@ -238,7 +238,7 @@ Artifact *RulesApplicator::createOutputArtifact(const RuleArtifactConstPtr &rule
             m_transformer = outputArtifact->transformer;
             m_transformer->inputs.unite(inputArtifacts);
 
-            if (m_transformer->inputs.count() > 1 && !m_rule->multiplex) {
+            if (Q_UNLIKELY(m_transformer->inputs.count() > 1 && !m_rule->multiplex)) {
                 QString th = "[" + outputArtifact->fileTags.toStringList().join(", ") + "]";
                 QString e = Tr::tr("Conflicting rules for producing %1 %2 \n").arg(outputArtifact->filePath(), th);
                 th = "[" + m_rule->inputs.toStringList().join(", ")
diff --git a/src/lib/buildgraph/rulesevaluationcontext.cpp b/src/lib/buildgraph/rulesevaluationcontext.cpp
index b4d7a139d..28a58b4be 100644
--- a/src/lib/buildgraph/rulesevaluationcontext.cpp
+++ b/src/lib/buildgraph/rulesevaluationcontext.cpp
@@ -71,7 +71,7 @@ void RulesEvaluationContext::incrementProgressValue()
 
 void RulesEvaluationContext::checkForCancelation()
 {
-    if (m_observer && m_observer->canceled())
+    if (Q_UNLIKELY(m_observer && m_observer->canceled()))
         throw Error(Tr::tr("Build canceled."));
 }
 
diff --git a/src/lib/buildgraph/transformer.cpp b/src/lib/buildgraph/transformer.cpp
index 646b0330f..4382637ac 100644
--- a/src/lib/buildgraph/transformer.cpp
+++ b/src/lib/buildgraph/transformer.cpp
@@ -137,14 +137,14 @@ void Transformer::createCommands(const PrepareScriptConstPtr &script,
     ScriptEngine * const engine = evalContext->engine();
     if (!script->scriptFunction.isValid() || script->scriptFunction.engine() != engine) {
         script->scriptFunction = engine->evaluate(script->script);
-        if (!script->scriptFunction.isFunction())
+        if (Q_UNLIKELY(!script->scriptFunction.isFunction()))
             throw Error(Tr::tr("Invalid prepare script."), script->location);
     }
 
     engine->clearProperties();
     QScriptValue scriptValue = script->scriptFunction.call();
     modulePropertiesUsedInPrepareScript = engine->properties();
-    if (engine->hasUncaughtException())
+    if (Q_UNLIKELY(engine->hasUncaughtException()))
         throw Error("evaluating prepare script: " + engine->uncaughtException().toString(),
                     CodeLocation(script->location.fileName,
                                  script->location.line + engine->uncaughtExceptionLineNumber() - 1));
diff --git a/src/lib/jsextensions/file.cpp b/src/lib/jsextensions/file.cpp
index c7dfd653b..c234fcee4 100644
--- a/src/lib/jsextensions/file.cpp
+++ b/src/lib/jsextensions/file.cpp
@@ -59,7 +59,7 @@ QScriptValue File::js_ctor(QScriptContext *context, QScriptEngine *engine)
 QScriptValue File::js_copy(QScriptContext *context, QScriptEngine *engine)
 {
     Q_UNUSED(engine);
-    if (context->argumentCount() < 2) {
+    if (Q_UNLIKELY(context->argumentCount() < 2)) {
         return context->throwError(QScriptContext::SyntaxError,
                                    Tr::tr("copy expects 2 arguments"));
     }
@@ -67,7 +67,7 @@ QScriptValue File::js_copy(QScriptContext *context, QScriptEngine *engine)
     const QString sourceFile = context->argument(0).toString();
     const QString targetFile = context->argument(1).toString();
     QString errorMessage;
-    if (!copyFileRecursion(sourceFile, targetFile, &errorMessage))
+    if (Q_UNLIKELY(!copyFileRecursion(sourceFile, targetFile, &errorMessage)))
         return context->throwError(errorMessage);
     return true;
 }
@@ -75,7 +75,7 @@ QScriptValue File::js_copy(QScriptContext *context, QScriptEngine *engine)
 QScriptValue File::js_exists(QScriptContext *context, QScriptEngine *engine)
 {
     Q_UNUSED(engine);
-    if (context->argumentCount() < 1) {
+    if (Q_UNLIKELY(context->argumentCount() < 1)) {
         return context->throwError(QScriptContext::SyntaxError,
                                    Tr::tr("exist expects 1 argument"));
     }
@@ -85,14 +85,14 @@ QScriptValue File::js_exists(QScriptContext *context, QScriptEngine *engine)
 QScriptValue File::js_remove(QScriptContext *context, QScriptEngine *engine)
 {
     Q_UNUSED(engine);
-    if (context->argumentCount() < 1) {
+    if (Q_UNLIKELY(context->argumentCount() < 1)) {
         return context->throwError(QScriptContext::SyntaxError,
                                    Tr::tr("remove expects 1 argument"));
     }
     QString fileName = context->argument(0).toString();
 
     QString errorMessage;
-    if (!removeFileRecursion(QFileInfo(fileName), &errorMessage))
+    if (Q_UNLIKELY(!removeFileRecursion(QFileInfo(fileName), &errorMessage)))
         return context->throwError(errorMessage);
     return true;
 }
diff --git a/src/lib/jsextensions/moduleproperties.cpp b/src/lib/jsextensions/moduleproperties.cpp
index a8fcf57fd..58bc6091f 100644
--- a/src/lib/jsextensions/moduleproperties.cpp
+++ b/src/lib/jsextensions/moduleproperties.cpp
@@ -81,19 +81,19 @@ QScriptValue ModuleProperties::js_moduleProperty(QScriptContext *context, QScrip
 QScriptValue ModuleProperties::moduleProperties(QScriptContext *context, QScriptEngine *engine,
                                                 bool oneValue)
 {
-    if (context->argumentCount() < 2) {
+    if (Q_UNLIKELY(context->argumentCount() < 2)) {
         return context->throwError(QScriptContext::SyntaxError,
                                    Tr::tr("Function moduleProperties() expects 2 arguments"));
     }
 
     const QScriptValue objectWithProperties = context->thisObject();
     const QScriptValue typeScriptValue = objectWithProperties.property(typeKey());
-    if (!typeScriptValue.isString()) {
+    if (Q_UNLIKELY(!typeScriptValue.isString())) {
         return context->throwError(QScriptContext::TypeError,
                 QLatin1String("Internal error: __type not set up"));
     }
     const QScriptValue ptrScriptValue = objectWithProperties.property(ptrKey());
-    if (!ptrScriptValue.isNumber()) {
+    if (Q_UNLIKELY(!ptrScriptValue.isNumber())) {
         return context->throwError(QScriptContext::TypeError,
                 QLatin1String("Internal error: __internalPtr not set up"));
     }
diff --git a/src/lib/jsextensions/textfile.cpp b/src/lib/jsextensions/textfile.cpp
index 73f96fc4a..ea42b55b9 100644
--- a/src/lib/jsextensions/textfile.cpp
+++ b/src/lib/jsextensions/textfile.cpp
@@ -98,7 +98,7 @@ TextFile::TextFile(QScriptContext *context, const QString &file, OpenMode mode,
     } else if (mode == WriteOnly) {
        m = QIODevice::WriteOnly;
     }
-    if (!t->qfile->open(m)) {
+    if (Q_UNLIKELY(!t->qfile->open(m))) {
         delete t->qfile;
         t->qfile = 0;
         context->throwError(QString::fromLatin1("unable to open '%1'")
diff --git a/src/lib/language/evaluatorscriptclass.cpp b/src/lib/language/evaluatorscriptclass.cpp
index 0f16e3991..16a206f40 100644
--- a/src/lib/language/evaluatorscriptclass.cpp
+++ b/src/lib/language/evaluatorscriptclass.cpp
@@ -356,7 +356,7 @@ QScriptValue EvaluatorScriptClass::scriptValueForBuiltin(BuiltinValue::Builtin b
 
 QScriptValue EvaluatorScriptClass::js_getenv(QScriptContext *context, QScriptEngine *engine)
 {
-    if (context->argumentCount() < 1) {
+    if (Q_UNLIKELY(context->argumentCount() < 1)) {
         return context->throwError(QScriptContext::SyntaxError,
                                    QLatin1String("getenv expects 1 argument"));
     }
diff --git a/src/lib/language/importversion.cpp b/src/lib/language/importversion.cpp
index 070ab7561..754359600 100644
--- a/src/lib/language/importversion.cpp
+++ b/src/lib/language/importversion.cpp
@@ -43,7 +43,7 @@ ImportVersion::ImportVersion()
 ImportVersion ImportVersion::fromString(const QString &str, const CodeLocation &location)
 {
     QStringList lst = str.split(QLatin1Char('.'));
-    if (lst.count() < 1 || lst.count() > 2)
+    if (Q_UNLIKELY(lst.count() < 1 || lst.count() > 2))
         throw Error(Tr::tr("Wrong number of components in import version."), location);
     ImportVersion v;
     int *parts[] = {&v.m_major, &v.m_minor, 0};
@@ -52,7 +52,7 @@ ImportVersion ImportVersion::fromString(const QString &str, const CodeLocation &
             break;
         bool ok;
         *parts[i] = lst.at(i).toInt(&ok);
-        if (!ok)
+        if (Q_UNLIKELY(!ok))
             throw Error(Tr::tr("Cannot parse import version."), location);
     }
     return v;
diff --git a/src/lib/language/itemreader.cpp b/src/lib/language/itemreader.cpp
index 27c63da0b..1c662d149 100644
--- a/src/lib/language/itemreader.cpp
+++ b/src/lib/language/itemreader.cpp
@@ -118,11 +118,11 @@ ItemReaderResult ItemReader::internalReadFile(const QString &filePath)
 {
     ASTCacheValue &cacheValue = (*m_astCache)[filePath];
     if (cacheValue.isValid()) {
-        if (cacheValue.isProcessing())
+        if (Q_UNLIKELY(cacheValue.isProcessing()))
             throw Error(Tr::tr("Loop detected when importing '%1'.").arg(filePath));
     } else {
         QFile file(filePath);
-        if (!file.open(QFile::ReadOnly))
+        if (Q_UNLIKELY(!file.open(QFile::ReadOnly)))
             throw Error(Tr::tr("Couldn't open '%1'.").arg(filePath));
 
         const QString code = QTextStream(&file).readAll();
@@ -133,7 +133,7 @@ ItemReaderResult ItemReader::internalReadFile(const QString &filePath)
         file.close();
         if (!parser.parse()) {
             QList<QbsQmlJS::DiagnosticMessage> parserMessages = parser.diagnosticMessages();
-            if (!parserMessages.isEmpty()) {
+            if (Q_UNLIKELY(!parserMessages.isEmpty())) {
                 Error err;
                 foreach (const QbsQmlJS::DiagnosticMessage &msg, parserMessages)
                     err.append(msg.message, toCodeLocation(filePath, msg.loc));
diff --git a/src/lib/language/itemreaderastvisitor.cpp b/src/lib/language/itemreaderastvisitor.cpp
index b7d7a8eb4..5c6ba26b0 100644
--- a/src/lib/language/itemreaderastvisitor.cpp
+++ b/src/lib/language/itemreaderastvisitor.cpp
@@ -67,7 +67,7 @@ bool ItemReaderASTVisitor::visit(AST::UiProgram *ast)
     m_file = FileContext::create();
     m_file->m_filePath = m_filePath;
 
-    if (!ast->members->member)
+    if (Q_UNLIKELY(!ast->members->member))
         throw Error(Tr::tr("No root item found in %1.").arg(m_filePath));
 
     return true;
@@ -129,18 +129,18 @@ bool ItemReaderASTVisitor::visit(AST::UiImportList *uiImportList)
 
         QString as;
         if (isBase) {
-            if (!import->importId.isNull()) {
+            if (Q_UNLIKELY(!import->importId.isNull())) {
                 throw Error(Tr::tr("Import of qbs.base must have no 'as <Name>'"),
                             toCodeLocation(import->importIdToken));
             }
         } else {
-            if (import->importId.isNull()) {
+            if (Q_UNLIKELY(import->importId.isNull())) {
                 throw Error(Tr::tr("Imports require 'as <Name>'"),
                             toCodeLocation(import->importToken));
             }
 
             as = import->importId.toString();
-            if (importAsNames.contains(as)) {
+            if (Q_UNLIKELY(importAsNames.contains(as))) {
                 throw Error(Tr::tr("Can't import into the same name more than once."),
                             toCodeLocation(import->importIdToken));
             }
@@ -151,7 +151,7 @@ bool ItemReaderASTVisitor::visit(AST::UiImportList *uiImportList)
             QString name = FileInfo::resolvePath(path, import->fileName.toString());
 
             QFileInfo fi(name);
-            if (!fi.exists())
+            if (Q_UNLIKELY(!fi.exists()))
                 throw Error(Tr::tr("Can't find imported file %0.").arg(name),
                             CodeLocation(m_filePath, import->fileNameToken.startLine,
                                          import->fileNameToken.startColumn));
@@ -198,7 +198,7 @@ bool ItemReaderASTVisitor::visit(AST::UiImportList *uiImportList)
                     break;
                 }
             }
-            if (!found) {
+            if (Q_UNLIKELY(!found)) {
                 throw Error(Tr::tr("import %1 not found").arg(importUri.join(".")),
                             toCodeLocation(import->fileNameToken));
             }
@@ -275,7 +275,7 @@ bool ItemReaderASTVisitor::visit(AST::UiObjectDefinition *ast)
 static void checkDuplicateBinding(const ItemPtr &item, const QStringList &bindingName,
                                   const AST::SourceLocation &sourceLocation)
 {
-    if (item->properties().contains(bindingName.last())) {
+    if (Q_UNLIKELY(item->properties().contains(bindingName.last()))) {
         QString msg = Tr::tr("Duplicate binding for '%1'");
         throw Error(msg.arg(bindingName.join(".")),
                     toCodeLocation(item->file()->filePath(), sourceLocation));
@@ -285,17 +285,17 @@ static void checkDuplicateBinding(const ItemPtr &item, const QStringList &bindin
 bool ItemReaderASTVisitor::visit(AST::UiPublicMember *ast)
 {
     PropertyDeclaration p;
-    if (ast->name.isEmpty())
+    if (Q_UNLIKELY(ast->name.isEmpty()))
         throw Error(Tr::tr("public member without name"));
-    if (ast->memberType.isEmpty())
+    if (Q_UNLIKELY(ast->memberType.isEmpty()))
         throw Error(Tr::tr("public member without type"));
-    if (ast->type == AST::UiPublicMember::Signal)
+    if (Q_UNLIKELY(ast->type == AST::UiPublicMember::Signal))
         throw Error(Tr::tr("public member with signal type not supported"));
     p.name = ast->name.toString();
     p.type = PropertyDeclaration::propertyTypeFromString(ast->memberType.toString());
     if (ast->typeModifier.compare(QLatin1String("list")))
         p.flags |= PropertyDeclaration::ListProperty;
-    else if (!ast->typeModifier.isEmpty())
+    else if (Q_UNLIKELY(!ast->typeModifier.isEmpty()))
         throw Error(Tr::tr("public member with type modifier '%1' not supported").arg(
                         ast->typeModifier.toString()));
 
@@ -325,11 +325,11 @@ bool ItemReaderASTVisitor::visit(AST::UiScriptBinding *ast)
     if (bindingName.length() == 1 && bindingName.first() == QLatin1String("id")) {
         AST::ExpressionStatement *expStmt =
                 AST::cast<AST::ExpressionStatement *>(ast->statement);
-        if (!expStmt)
+        if (Q_UNLIKELY(!expStmt))
             throw Error(Tr::tr("id: must be followed by identifier"));
         AST::IdentifierExpression *idExp =
                 AST::cast<AST::IdentifierExpression *>(expStmt->expression);
-        if (!idExp || idExp->name.isEmpty())
+        if (Q_UNLIKELY(!idExp || idExp->name.isEmpty()))
             throw Error(Tr::tr("id: must be followed by identifier"));
         m_item->m_id = idExp->name.toString();
         ensureIdScope(m_file);
@@ -352,7 +352,7 @@ bool ItemReaderASTVisitor::visit(AST::UiScriptBinding *ast)
 bool ItemReaderASTVisitor::visit(AST::FunctionDeclaration *ast)
 {
     FunctionDeclaration f;
-    if (ast->name.isNull())
+    if (Q_UNLIKELY(ast->name.isNull()))
         throw Error(Tr::tr("function decl without name"));
     f.setName(ast->name.toString());
 
@@ -408,7 +408,7 @@ ItemPtr ItemReaderASTVisitor::targetItemForBinding(const ItemPtr &item,
             v = ItemValue::create(newItem);
             targetItem->m_properties.insert(bindingName.at(i), v);
         }
-        if (v->type() != Value::ItemValueType) {
+        if (Q_UNLIKELY(v->type() != Value::ItemValueType)) {
             QString msg = Tr::tr("Binding to non-item property.");
             throw Error(msg, bindingLocation);
         }
@@ -425,7 +425,7 @@ void ItemReaderASTVisitor::checkImportVersion(const AST::SourceLocation &version
     const QString importVersionString = m_sourceCode.mid(versionToken.offset, versionToken.length);
     const ImportVersion importVersion
             = ImportVersion::fromString(importVersionString, toCodeLocation(versionToken));
-    if (importVersion != m_languageVersion)
+    if (Q_UNLIKELY(importVersion != m_languageVersion))
         throw Error(Tr::tr("Incompatible qbs version %1. This is qbs %2.").arg(
                         importVersionString, m_reader->builtins()->languageVersion()),
                     toCodeLocation(versionToken));
@@ -553,7 +553,7 @@ private:
                       it.value().staticCast<ItemValue>()->item());
             } else if (it.value()->type() == Value::JSSourceValueType) {
                 ValuePtr aval = a->property(it.key());
-                if (aval && aval->type() != Value::JSSourceValueType)
+                if (Q_UNLIKELY(aval && aval->type() != Value::JSSourceValueType))
                     throw Error(Tr::tr("Incompatible value type in unconditional value at %1.").arg(
                                     aval->location().toString()));
                 apply(it.key(), a, aval.staticCast<JSSourceValue>(),
@@ -583,10 +583,10 @@ private:
 void ItemReaderASTVisitor::handlePropertiesBlock(const ItemPtr &item, const ItemConstPtr &block)
 {
     ValuePtr value = block->property(QLatin1String("condition"));
-    if (!value)
+    if (Q_UNLIKELY(!value))
         throw Error(Tr::tr("Properties.condition must be provided."),
                     block->location());
-    if (value->type() != Value::JSSourceValueType)
+    if (Q_UNLIKELY(value->type() != Value::JSSourceValueType))
         throw Error(Tr::tr("Properties.condition must be a value binding."),
                     block->location());
     JSSourceValuePtr srcval = value.staticCast<JSSourceValue>();
diff --git a/src/lib/language/language.cpp b/src/lib/language/language.cpp
index 08db12ec3..0efb8c1fd 100644
--- a/src/lib/language/language.cpp
+++ b/src/lib/language/language.cpp
@@ -414,7 +414,7 @@ QList<const ResolvedModule*> topSortModules(const QHash<const ResolvedModule*, Q
 
 static QScriptValue js_getenv(QScriptContext *context, QScriptEngine *engine)
 {
-    if (context->argumentCount() < 1)
+    if (Q_UNLIKELY(context->argumentCount() < 1))
         return context->throwError(QScriptContext::SyntaxError,
                                    QLatin1String("getenv expects 1 argument"));
     QVariant v = engine->property("_qbs_procenv");
@@ -424,7 +424,7 @@ static QScriptValue js_getenv(QScriptContext *context, QScriptEngine *engine)
 
 static QScriptValue js_putenv(QScriptContext *context, QScriptEngine *engine)
 {
-    if (context->argumentCount() < 2)
+    if (Q_UNLIKELY(context->argumentCount() < 2))
         return context->throwError(QScriptContext::SyntaxError,
                                    QLatin1String("putenv expects 2 arguments"));
     QVariant v = engine->property("_qbs_procenv");
@@ -526,7 +526,7 @@ static QProcessEnvironment getProcessEnvironment(ScriptEngine *engine, EnvType e
         ctx->pushScope(scope);
         scriptValue = engine->evaluate(setupScript);
         ctx->popScope();
-        if (scriptValue.isError() || engine->hasUncaughtException()) {
+        if (Q_UNLIKELY(scriptValue.isError() || engine->hasUncaughtException())) {
             QString envTypeStr = (envType == BuildEnv ? "build" : "run");
             throw Error(QString("Error while setting up %1 environment: %2").arg(envTypeStr, scriptValue.toString()));
         }
diff --git a/src/lib/language/moduleloader.cpp b/src/lib/language/moduleloader.cpp
index 06a9fa59b..6ae1b3189 100644
--- a/src/lib/language/moduleloader.cpp
+++ b/src/lib/language/moduleloader.cpp
@@ -239,7 +239,7 @@ void ModuleLoader::handleProductModule(ModuleLoader::ProductContext *productCont
                                        const ItemPtr &item)
 {
     checkCancelation();
-    if (productContext->filesWithProductModule.contains(item->file()))
+    if (Q_UNLIKELY(productContext->filesWithProductModule.contains(item->file())))
         throw Error(Tr::tr("Multiple ProductModule items in one product are prohibited."),
                     item->location());
     productContext->filesWithProductModule += item->file();
@@ -277,7 +277,7 @@ void ModuleLoader::resolveDependencies(DependsContext *dependsContext, const Ite
     Item::Module baseModuleDesc;
     baseModuleDesc.name = baseModuleName;
     baseModuleDesc.item = loadModule(dependsContext->product, item, QString(), baseModuleName);
-    if (!baseModuleDesc.item)
+    if (Q_UNLIKELY(!baseModuleDesc.item))
         throw Error(Tr::tr("Cannot load base qbs module."));
     baseModuleDesc.item->setProperty(QLatin1String("getenv"),
                                      BuiltinValue::create(BuiltinValue::GetEnvFunction));
@@ -322,7 +322,7 @@ void ModuleLoader::resolveDependsItem(DependsContext *dependsContext, const Item
     checkCancelation();
     const QString name = m_evaluator->property(dependsItem, "name").toString().toLower();
     const QStringList nameParts = name.split('.');
-    if (nameParts.count() > 2) {
+    if (Q_UNLIKELY(nameParts.count() > 2)) {
         QString msg = Tr::tr("There cannot be more than one dot in a module name.");
         throw Error(msg, dependsItem->location());
     }
@@ -330,13 +330,13 @@ void ModuleLoader::resolveDependsItem(DependsContext *dependsContext, const Item
     QString superModuleName;
     QStringList submodules = toStringList(m_evaluator->property(dependsItem, "submodules"));
     if (nameParts.count() == 2) {
-        if (!submodules.isEmpty())
+        if (Q_UNLIKELY(!submodules.isEmpty()))
             throw Error(Tr::tr("Depends.submodules cannot be used if name contains a dot."),
                         dependsItem->location());
         superModuleName = nameParts.first();
         submodules += nameParts.last();
     }
-    if (submodules.count() > 1 && !dependsItem->id().isEmpty()) {
+    if (Q_UNLIKELY(submodules.count() > 1 && !dependsItem->id().isEmpty())) {
         QString msg = Tr::tr("A Depends item with more than one module cannot have an id.");
         throw Error(msg, dependsItem->location());
     }
@@ -473,7 +473,7 @@ ItemPtr ModuleLoader::searchAndLoadModuleFile(ProductContext *productContext,
         }
     }
 
-    if (triedToLoadModule)
+    if (Q_UNLIKELY(triedToLoadModule))
         throw Error(Tr::tr("Module %1 could not be loaded.").arg(fullModuleName(moduleName)));
 
     return ItemPtr();
@@ -595,7 +595,7 @@ void ModuleLoader::instantiateModule(ProductContext *productContext, const ItemP
     for (QVariantMap::const_iterator vmit = userModuleProperties.begin();
          vmit != userModuleProperties.end(); ++vmit)
     {
-        if (!moduleInstance->hasProperty(vmit.key()))
+        if (Q_UNLIKELY(!moduleInstance->hasProperty(vmit.key())))
             throw Error(Tr::tr("Unknown property: %1.%2").arg(fullModuleName(moduleName), vmit.key()));
         moduleInstance->setProperty(vmit.key(), VariantValue::create(vmit.value()));
     }
@@ -628,7 +628,7 @@ void ModuleLoader::resolveProbes(const ItemPtr &item)
 void ModuleLoader::resolveProbe(const ItemPtr &parent, const ItemPtr &probe)
 {
     const JSSourceValueConstPtr configureScript = probe->sourceProperty(QLatin1String("configure"));
-    if (!configureScript)
+    if (Q_UNLIKELY(!configureScript))
         throw Error(Tr::tr("Probe.configure must be set."), probe->location());
     typedef QPair<QString, QScriptValue> ProbeProperty;
     QList<ProbeProperty> probeBindings;
@@ -637,7 +637,7 @@ void ModuleLoader::resolveProbe(const ItemPtr &parent, const ItemPtr &probe)
             if (name == QLatin1String("configure"))
                 continue;
             QScriptValue sv = m_evaluator->property(probe, name);
-            if (sv.isError()) {
+            if (Q_UNLIKELY(sv.isError())) {
                 ValuePtr value = obj->property(name);
                 throw Error(sv.toString(), value ? value->location() : CodeLocation());
             }
@@ -654,7 +654,7 @@ void ModuleLoader::resolveProbe(const ItemPtr &parent, const ItemPtr &probe)
     foreach (const ProbeProperty &b, probeBindings)
         scope.setProperty(b.first, b.second);
     QScriptValue sv = m_engine->evaluate(configureScript->sourceCode());
-    if (sv.isError())
+    if (Q_UNLIKELY(sv.isError()))
         throw Error(sv.toString(), configureScript->location());
     foreach (const ProbeProperty &b, probeBindings) {
         const QVariant newValue = scope.property(b.first).toVariant();
@@ -679,7 +679,7 @@ bool ModuleLoader::checkItemCondition(const ItemPtr &item)
         // Item doesn't have a condition binding. Handled as true.
         return true;
     }
-    if (value.isError()) {
+    if (Q_UNLIKELY(value.isError())) {
         CodeLocation location;
         ValuePtr prop = item->property("condition");
         if (prop && prop->type() == Value::JSSourceValueType)
diff --git a/src/lib/language/projectresolver.cpp b/src/lib/language/projectresolver.cpp
index 7039719d5..1214451a1 100644
--- a/src/lib/language/projectresolver.cpp
+++ b/src/lib/language/projectresolver.cpp
@@ -104,7 +104,7 @@ void ProjectResolver::checkCancelation() const
 bool ProjectResolver::boolValue(const ItemConstPtr &item, const QString &name, bool defaultValue) const
 {
     QScriptValue v = m_evaluator->property(item, name);
-    if (v.isError()) {
+    if (Q_UNLIKELY(v.isError())) {
         ValuePtr value = item->property(name);
         throw Error(v.toString(), value ? value->location() : CodeLocation());
     }
@@ -122,7 +122,7 @@ QString ProjectResolver::stringValue(const ItemConstPtr &item, const QString &na
                                      const QString &defaultValue) const
 {
     QScriptValue v = m_evaluator->property(item, name);
-    if (v.isError()) {
+    if (Q_UNLIKELY(v.isError())) {
         ValuePtr value = item->property(name);
         throw Error(v.toString(), value ? value->location() : CodeLocation());
     }
@@ -134,7 +134,7 @@ QString ProjectResolver::stringValue(const ItemConstPtr &item, const QString &na
 QStringList ProjectResolver::stringListValue(const ItemConstPtr &item, const QString &name) const
 {
     QScriptValue v = m_evaluator->property(item, name);
-    if (v.isError()) {
+    if (Q_UNLIKELY(v.isError())) {
         ValuePtr value = item->property(name);
         throw Error(v.toString(), value ? value->location() : CodeLocation());
     }
@@ -341,7 +341,7 @@ void ProjectResolver::resolveGroup(const ItemPtr &item)
     QStringList files = stringListValue(item, QLatin1String("files"));
     const QStringList fileTagsFilter = stringListValue(item, QLatin1String("fileTagsFilter"));
     if (!fileTagsFilter.isEmpty()) {
-        if (!files.isEmpty())
+        if (Q_UNLIKELY(!files.isEmpty()))
             throw Error(Tr::tr("Group.files and Group.fileTagsFilters are exclusive."),
                         item->location());
         ArtifactPropertiesPtr aprops = ArtifactProperties::create();
@@ -352,7 +352,7 @@ void ProjectResolver::resolveGroup(const ItemPtr &item)
         m_productContext->product->artifactProperties += aprops;
         return;
     }
-    if (files.isEmpty() && !item->hasProperty(QLatin1String("files"))) {
+    if (Q_UNLIKELY(files.isEmpty() && !item->hasProperty(QLatin1String("files")))) {
         // Yield an error if Group without files binding is encountered.
         // An empty files value is OK but a binding must exist.
         throw Error(Tr::tr("Group without files is not allowed."),
@@ -423,14 +423,14 @@ void ProjectResolver::resolveRule(const ItemPtr &item)
     // read artifacts
     bool hasAlwaysUpdatedArtifact = false;
     foreach (const ItemPtr &child, item->children()) {
-        if (child->typeName() != QLatin1String("Artifact"))
+        if (Q_UNLIKELY(child->typeName() != QLatin1String("Artifact")))
             throw Error(Tr::tr("'Rule' can only have children of type 'Artifact'."),
                                child->location());
 
         resolveRuleArtifact(rule, child, &hasAlwaysUpdatedArtifact);
     }
 
-    if (!hasAlwaysUpdatedArtifact)
+    if (Q_UNLIKELY(!hasAlwaysUpdatedArtifact))
         throw Error(Tr::tr("At least one output artifact of a rule "
                            "must have alwaysUpdated set to true."),
                     item->location());
@@ -561,12 +561,12 @@ void ProjectResolver::resolveTransformer(const ItemPtr &item)
     rtrafo->transform = transform;
 
     foreach (const ItemConstPtr &child, item->children()) {
-        if (child->typeName() != QLatin1String("Artifact"))
+        if (Q_UNLIKELY(child->typeName() != QLatin1String("Artifact")))
             throw Error(Tr::tr("Transformer: wrong child type '%0'.").arg(child->typeName()));
         SourceArtifactPtr artifact = SourceArtifact::create();
         artifact->properties = m_productContext->product->properties;
         QString fileName = stringValue(child, "fileName");
-        if (fileName.isEmpty())
+        if (Q_UNLIKELY(fileName.isEmpty()))
             throw Error(Tr::tr("Artifact fileName must not be empty."));
         artifact->absoluteFilePath = FileInfo::resolvePath(m_productContext->product->project->buildDirectory,
                                                            fileName);
@@ -627,7 +627,7 @@ void ProjectResolver::resolveProductDependencies()
                         productInfo.usedProducts) {
                 ResolvedProductPtr usedProduct
                         = m_projectContext->productsByName.value(dependency.name);
-                if (!usedProduct)
+                if (Q_UNLIKELY(!usedProduct))
                     throw Error(Tr::tr("Product dependency '%1' not found.").arg(dependency.name),
                                 productItem->location());
                 const ItemPtr usedProductItem = m_projectContext->productItemMap.value(usedProduct);
@@ -649,7 +649,7 @@ void ProjectResolver::resolveProductDependencies()
             const QString &usedProductName = dependency.name;
             ResolvedProductPtr usedProduct
                     = m_projectContext->productsByName.value(usedProductName);
-            if (!usedProduct)
+            if (Q_UNLIKELY(!usedProduct))
                 throw Error(Tr::tr("Product dependency '%1' not found.").arg(usedProductName),
                             productItem->location());
             rproduct->dependencies.insert(usedProduct);
@@ -762,7 +762,7 @@ QVariantMap ProjectResolver::evaluateProperties(const ItemPtr &item,
                 break;
             }
             const QScriptValue scriptValue = m_evaluator->property(item, it.key());
-            if (scriptValue.isError())
+            if (Q_UNLIKELY(scriptValue.isError()))
                 throw Error(scriptValue.toString(), it.value()->location());
             QVariant v = scriptValue.toVariant();
             if (pd.type == PropertyDeclaration::Path)
@@ -816,7 +816,7 @@ void ProjectResolver::callItemFunction(const ItemFuncMap &mappings,
 {
     const QByteArray typeName = item->typeName().toLocal8Bit();
     ItemFuncPtr f = mappings.value(typeName);
-    if (!f) {
+    if (Q_UNLIKELY(!f)) {
         const QString msg = Tr::tr("Unexpected item type '%1'.");
         throw Error(msg.arg(item->typeName()), item->location());
     }
diff --git a/src/lib/language/scriptengine.cpp b/src/lib/language/scriptengine.cpp
index d8c80f903..e28140e28 100644
--- a/src/lib/language/scriptengine.cpp
+++ b/src/lib/language/scriptengine.cpp
@@ -90,7 +90,7 @@ void ScriptEngine::import(const JsImport &jsImport, QScriptValue scope, QScriptV
             if (debugJSImports)
                 m_logger.qbsDebug() << "[ENGINE] " << fileName << " (cache miss)";
             QFile file(fileName);
-            if (!file.open(QFile::ReadOnly))
+            if (Q_UNLIKELY(!file.open(QFile::ReadOnly)))
                 throw Error(tr("Cannot open '%1'.").arg(fileName));
             const QString sourceCode = QTextStream(&file).readAll();
             file.close();
@@ -181,7 +181,7 @@ void ScriptEngine::importProgram(const QScriptProgram &program, const QScriptVal
     if (scope.isObject())
         currentContext()->popScope();
     popContext();
-    if (result.isError())
+    if (Q_UNLIKELY(result.isError()))
         throw Error(tr("Error when importing '%1': %2").arg(program.fileName(), result.toString()));
 
     // If targetObject is already an object, it doesn't get overwritten but enhanced by the
diff --git a/src/lib/tools/persistence.cpp b/src/lib/tools/persistence.cpp
index a4be67ad8..04d8cfcf2 100644
--- a/src/lib/tools/persistence.cpp
+++ b/src/lib/tools/persistence.cpp
@@ -152,7 +152,7 @@ void PersistentPool::storeString(const QString &t)
 
 QString PersistentPool::loadString(int id)
 {
-    if (id < 0)
+    if (Q_UNLIKELY(id < 0))
         throw Error("loadString with negative id called");
 
     if (id >= m_stringStorage.count()) {
diff --git a/src/lib/tools/profile.cpp b/src/lib/tools/profile.cpp
index a4eb9c8b8..670551f96 100644
--- a/src/lib/tools/profile.cpp
+++ b/src/lib/tools/profile.cpp
@@ -201,7 +201,7 @@ QStringList Profile::allKeysInternal(Profile::KeySelection selection,
 void Profile::extendAndCheckProfileChain(QStringList &chain) const
 {
     chain << m_name;
-    if (chain.count(m_name) > 1) {
+    if (Q_UNLIKELY(chain.count(m_name) > 1)) {
         throw Error(Internal::Tr::tr("Circular profile inheritance. Cycle is '%1'.")
                     .arg(chain.join(QLatin1String(" -> "))));
     }
diff --git a/src/lib/tools/qbsassert.h b/src/lib/tools/qbsassert.h
index 0410d88d8..686c08ab5 100644
--- a/src/lib/tools/qbsassert.h
+++ b/src/lib/tools/qbsassert.h
@@ -42,7 +42,7 @@ void QBS_EXPORT throwAssertLocation(const char *condition, const char *file, int
 } // namespace qbs
 
 #define QBS_ASSERT(cond, action)\
-    if (cond) {} else {\
+    if (Q_LIKELY(cond)) {} else {\
         ::qbs::Internal::writeAssertLocation(#cond, __FILE__, __LINE__); action;\
     } do {} while (0)
 
@@ -51,7 +51,7 @@ void QBS_EXPORT throwAssertLocation(const char *condition, const char *file, int
 
 #define QBS_CHECK(cond)\
     do {\
-        if (cond) {} else {\
+        if (Q_LIKELY(cond)) {} else {\
             ::qbs::Internal::throwAssertLocation(#cond, __FILE__, __LINE__);\
         }\
     } while (0)