Verifier: Check wchar_size module flag.

[MatzeB]

ping

llvm/trunk/lib/IR/Verifier.cpp

Verifier::visitModuleFlag(const MDNode *Op,
   }
 
   // Unless this is a "requires" flag, check the ID is unique.
   if (MFB != Module::Require) {
     bool Inserted = SeenIDs.insert(std::make_pair(ID, Op)).second;
     Assert(Inserted,
            "module flag identifiers must be unique (or of 'require' type)", ID);
   }
+
+  if (ID->getString() == "wchar_size") {
+    ConstantInt *Value
+      = mdconst::dyn_extract_or_null<ConstantInt>(Op->getOperand(2));
+    Assert(Value, "wchar_size metadata requires constant integer argument");
+    uint64_t WCharSize = Value->getZExtValue();
+    Assert(WCharSize == 0 || WCharSize == 2 || WCharSize == 4,
+           "wchar_size should be 0, 2 or 4");
+  }
 }
 
 /// Return true if this attribute kind only applies to functions.
 static bool isFuncOnlyAttr(Attribute::AttrKind Kind) {
   switch (Kind) {
   case Attribute::NoReturn:
   case Attribute::NoUnwind:
   case Attribute::NoInline: