[analyzer] Teach CallEvent about C++17 aligned operator new().

In C++17, when class C has large alignment value, a special case of
overload resolution rule kicks in for expression new C that causes the aligned
version of operator new() to be called. The aligned new has two arguments:
size and alignment. However, the new-expression has only one "argument":
the construct-expression for C(). This causes a false positive in
core.CallAndMessage's check for matching number of arguments and number
of parameters.

Update CXXAllocatorCall, which is a CallEvent sub-class for operator new calls
within new-expressions, so that the number of arguments always matched
the number of parameters.

rdar://problem/44738501

Differential Revision: https://reviews.llvm.org/D52957

llvm-svn: 344539

1 files changed, 4 insertions, 0 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
index 7b6a8d4d252..e0759d107a9 100644
--- a/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
+++ b/clang/lib/StaticAnalyzer/Core/CallEvent.cpp
@@ -503,10 +503,14 @@ static void addParameterValuesToBindings(const StackFrameContext *CalleeCtx,
     const ParmVarDecl *ParamDecl = *I;
     assert(ParamDecl && "Formal parameter has no decl?");
 
+    // TODO: Support allocator calls.
     if (Call.getKind() != CE_CXXAllocator)
       if (Call.isArgumentConstructedDirectly(Idx))
         continue;
 
+    // TODO: Allocators should receive the correct size and possibly alignment,
+    // determined in compile-time but not represented as arg-expressions,
+    // which makes getArgSVal() fail and return UnknownVal.
     SVal ArgVal = Call.getArgSVal(Idx);
     if (!ArgVal.isUnknown()) {
       Loc ParamLoc = SVB.makeLoc(MRMgr.getVarRegion(ParamDecl, CalleeCtx));