[Libreoffice-commits] core.git: compilerplugins/clang

[Stephan Bergmann]

 compilerplugins/clang/passstuffbyref.cxx      |    7 +++++--
 compilerplugins/clang/test/passstuffbyref.cxx |    7 +++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

New commits:
commit 37fe0f729c17bd30d9f273b268b15c353c34a156
Author: Stephan Bergmann <sbergman at redhat.com>
Date:   Tue Dec 5 23:00:58 2017 +0100

    Better heuristic to only look through implicit copy/move ctors
    
    At least recent libc++ has a std::string ctor overload without a (defaulted)
    Allocator argument (which otherwise causes creation of a temporary Allocator
    object and thus a ExprWithCleanups), so in C++17 mode (i.e., with no implicit
    move CXXConstructExpr -> MaterializeTemporaryExpr -> CXXBindTemporaryExpr chain
    in the way) CellInfo::toString (sw/source/filter/ww8/WW8TableInfo.cxx) has a
    ReturnStmt of just
    
    > ReturnStmt
    > `-ImplicitCastExpr 'std::string':'class std::__1::basic_string<char>' <ConstructorConversion>
    >   `-CXXConstructExpr 'std::string':'class std::__1::basic_string<char>' 'void (const char *)'
    >     `-ImplicitCastExpr 'const char *' <NoOp>
    >       `-ImplicitCastExpr 'char *' <ArrayToPointerDecay>
    >         `-DeclRefExpr 'char [256]' lvalue Var 'sBuffer' 'char [256]'
    
    that erroneously triggered loplugin:passstuffbyref.
    
    Change-Id: I53c8911cb1356560692c003808280a103c399e25
    Reviewed-on: https://gerrit.libreoffice.org/45916
    Tested-by: Jenkins <ci at libreoffice.org>
    Reviewed-by: Stephan Bergmann <sbergman at redhat.com>

diff --git a/compilerplugins/clang/passstuffbyref.cxx b/compilerplugins/clang/passstuffbyref.cxx
index f87e668ed4fa..3b4b974c697f 100644
--- a/compilerplugins/clang/passstuffbyref.cxx
+++ b/compilerplugins/clang/passstuffbyref.cxx
@@ -310,8 +310,11 @@ bool PassStuffByRef::isReturnExprDisqualified(const Expr* expr)
     if (isa<ExprWithCleanups>(expr)) {
         return true;
     }
-    if (const CXXConstructExpr* constructExpr = dyn_cast<CXXConstructExpr>(expr)) {
-        if (constructExpr->getNumArgs()==1) {
+    if (const CXXConstructExpr* constructExpr = dyn_cast<CXXConstructExpr>(expr))
+    {
+        if (constructExpr->getNumArgs()==1
+            && constructExpr->getConstructor()->isCopyOrMoveConstructor())
+        {
             expr = constructExpr->getArg(0)->IgnoreParenCasts();
         }
     }
diff --git a/compilerplugins/clang/test/passstuffbyref.cxx b/compilerplugins/clang/test/passstuffbyref.cxx
index 89f51fb1c294..2f076e58e7b7 100644
--- a/compilerplugins/clang/test/passstuffbyref.cxx
+++ b/compilerplugins/clang/test/passstuffbyref.cxx
@@ -26,6 +26,13 @@ void f()
     s = new S(v1, v2);
 }
 
+struct S2 { S2(int); };
+
+S2 f2() {
+    static int n;
+    return n;
+}
+
 // expected-no-diagnostics
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */