improve loplugin simplifyconstruct

to find stuff like
   OUString s = OUString("xxx")

Change-Id: Ie7ed074c1ae012734c67a2a89c564c1900a4ab04
Reviewed-on: https://gerrit.libreoffice.org/70697
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

3 files changed, 73 insertions, 0 deletions

diff --git a/compilerplugins/clang/sharedvisitor/sharedvisitor.cxx b/compilerplugins/clang/sharedvisitor/sharedvisitor.cxx
index 5b72c329691d..66e43b96f67b 100644
--- a/compilerplugins/clang/sharedvisitor/sharedvisitor.cxx
+++ b/compilerplugins/clang/sharedvisitor/sharedvisitor.cxx
@@ -626,6 +626,11 @@ public:
             if( !externVar->VisitVarDecl( arg ))
                 externVar = nullptr;
         }
+        if( simplifyConstruct != nullptr )
+        {
+            if( !simplifyConstruct->VisitVarDecl( arg ))
+                simplifyConstruct = nullptr;
+        }
         if( stringStatic != nullptr )
         {
             if( !stringStatic->VisitVarDecl( arg ))
diff --git a/compilerplugins/clang/simplifyconstruct.cxx b/compilerplugins/clang/simplifyconstruct.cxx
index 652a980cec6a..c3e28ce7bcda 100644
--- a/compilerplugins/clang/simplifyconstruct.cxx
+++ b/compilerplugins/clang/simplifyconstruct.cxx
@@ -31,6 +31,7 @@ public:
     virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
 
     bool VisitCXXConstructExpr(CXXConstructExpr const*);
+    bool VisitVarDecl(VarDecl const*);
 
     // ignore some contexts within which nullptr is fine
     bool TraverseReturnStmt(ReturnStmt*) { return true; }
@@ -69,6 +70,42 @@ bool SimplifyConstruct::VisitCXXConstructExpr(CXXConstructExpr const* constructE
     return true;
 }
 
+bool SimplifyConstruct::VisitVarDecl(VarDecl const* varDecl)
+{
+    if (ignoreLocation(varDecl))
+        return true;
+    // cannot use OUString s("xxx") style syntax in a parameter
+    if (isa<ParmVarDecl>(varDecl))
+        return true;
+    varDecl = varDecl->getCanonicalDecl();
+    if (!varDecl->getInit())
+        return true;
+    if (varDecl->getInitStyle() != VarDecl::InitializationStyle::CInit)
+        return true;
+    if (!varDecl->getType()->isRecordType())
+        return true;
+    if (isa<AutoType>(varDecl->getType()))
+        return true;
+
+    auto init = varDecl->getInit()->IgnoreImplicit();
+    auto functionalCast = dyn_cast<CXXFunctionalCastExpr>(init);
+    if (!functionalCast)
+        return true;
+
+    // e.g. the LANGUAGE_DONTKNOW defines
+    if (compiler.getSourceManager().isMacroBodyExpansion(compat::getBeginLoc(init)))
+        return true;
+
+    //    varDecl->getInit()->IgnoreImplicit()->dump();
+    //    varDecl->getType()->dump();
+    //    varDecl->getType()->getUnqualifiedDesugaredType()->dump();
+
+    report(DiagnosticsEngine::Warning, "simplify", varDecl->getLocation())
+        << varDecl->getSourceRange();
+
+    return true;
+}
+
 loplugin::Plugin::Registration<SimplifyConstruct> simplifyconstruct("simplifyconstruct", true);
 }
 
diff --git a/compilerplugins/clang/test/simplifyconstruct.cxx b/compilerplugins/clang/test/simplifyconstruct.cxx
index ca4b3a1a198c..8fbffc8ba2d7 100644
--- a/compilerplugins/clang/test/simplifyconstruct.cxx
+++ b/compilerplugins/clang/test/simplifyconstruct.cxx
@@ -10,6 +10,8 @@
 #include <memory>
 #include <rtl/ref.hxx>
 
+namespace test1
+{
 struct Foo
 {
     void acquire();
@@ -27,8 +29,11 @@ class Foo1
     {
     }
 };
+}
 
 // no warning expected when using std::unique_ptr constructor with a custom deleter
+namespace test2
+{
 struct ITypeLib
 {
 };
@@ -43,5 +48,31 @@ void func2()
             p->Release();
     });
 }
+}
+
+namespace test3
+{
+struct Foo
+{
+    void acquire();
+    void release();
+};
+void f(Foo* f)
+{
+    // expected-error@+1 {{simplify [loplugin:simplifyconstruct]}}
+    rtl::Reference<Foo> x = rtl::Reference(f);
+}
+}
+
+// no warning expected
+namespace test4
+{
+struct Foo
+{
+    void acquire();
+    void release();
+};
+void f(Foo* f) { auto x = rtl::Reference(f); }
+}
 
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