[CFG] [analyzer] Disable argument construction contexts for variadic functions.

The analyzer doesn't make use of them anyway and they seem to have
pretty weird AST from time to time, so let's just skip them for now.

Fixes pr37769.

Differential Revision: https://reviews.llvm.org/D50824

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@340975 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/CFG.cpp b/lib/Analysis/CFG.cpp
index ae7917d6772d39a09845dcf0df2e1f40e9c0917a..48113eb6ba5f3da8b4322f1952130386107e17e6 100644 (file)
--- a/lib/Analysis/CFG.cpp
+++ b/lib/Analysis/CFG.cpp
@@ -2421,8 +2421,6 @@ CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
     if (!boundType.isNull()) calleeType = boundType;
   }
 
-  findConstructionContextsForArguments(C);
-
   // If this is a call to a no-return function, this stops the block here.
   bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn();
 
@@ -2439,6 +2437,13 @@ CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) {
   bool OmitArguments = false;
 
   if (FunctionDecl *FD = C->getDirectCallee()) {
+    // TODO: Support construction contexts for variadic function arguments.
+    // These are a bit problematic and not very useful because passing
+    // C++ objects as C-style variadic arguments doesn't work in general
+    // (see [expr.call]).
+    if (!FD->isVariadic())
+      findConstructionContextsForArguments(C);
+
     if (FD->isNoReturn() || C->isBuiltinAssumeFalse(*Context))
       NoReturn = true;
     if (FD->hasAttr<NoThrowAttr>())

diff --git a/test/Analysis/cfg-rich-constructors.cpp b/test/Analysis/cfg-rich-constructors.cpp
index ca74b7c93cf76be087f75901ff234bd23a93eedc..31c306bbfe9c5c411270b4e5f34228e1b9e42215 100644 (file)
--- a/test/Analysis/cfg-rich-constructors.cpp
+++ b/test/Analysis/cfg-rich-constructors.cpp
@@ -1028,3 +1028,18 @@ void testOperators() {
   C(1) + C(2);
 }
 } // namespace operators
+
+namespace variadic_function_arguments {
+class C {
+ public:
+  C(int);
+};
+
+int variadic(...);
+
+// This code is quite exotic, so let's not test the CFG for it,
+// but only make sure we don't crash.
+void testCrashOnVariadicArgument() {
+  C c(variadic(0 ? c : 0)); // no-crash
+}
+} // namespace variadic_function_arguments