Added support for the Builtin attribute.

The Builtin attribute is an attribute that can be placed on function call site that signal that even though a function is declared as being a builtin,

rdar://problem/13727199

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185049 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/IR/Verifier.cpp b/lib/IR/Verifier.cpp
index 1b1b3b8..7123eaf 100644
--- a/lib/IR/Verifier.cpp
+++ b/lib/IR/Verifier.cpp
@@ -692,6 +692,7 @@
         I->getKindAsEnum() == Attribute::SanitizeMemory ||
         I->getKindAsEnum() == Attribute::MinSize ||
         I->getKindAsEnum() == Attribute::NoDuplicate ||
+        I->getKindAsEnum() == Attribute::Builtin ||
         I->getKindAsEnum() == Attribute::NoBuiltin ||
         I->getKindAsEnum() == Attribute::Cold) {
       if (!isFunction)
@@ -877,6 +878,13 @@
   // Check function attributes.
   VerifyFunctionAttrs(FT, Attrs, &F);
 
+  // On function declarations/definitions, we do not support the builtin
+  // attribute. We do not check this in VerifyFunctionAttrs since that is
+  // checking for Attributes that can/can not ever be on functions.
+  Assert1(!Attrs.hasAttribute(AttributeSet::FunctionIndex,
+                              Attribute::Builtin),
+          "Attribute 'builtin' can only be applied to a callsite.", &F);
+
   // Check that this function meets the restrictions on this calling convention.
   switch (F.getCallingConv()) {
   default:
@@ -1435,6 +1443,14 @@
               "Function has metadata parameter but isn't an intrinsic", I);
   }
 
+  // If the call site has the 'builtin' attribute, verify that it's applied to a
+  // direct call to a function with the 'nobuiltin' attribute.
+  if (CS.hasFnAttr(Attribute::Builtin))
+    Assert1(CS.getCalledFunction() &&
+            CS.getCalledFunction()->hasFnAttribute(Attribute::NoBuiltin),
+            "Attribute 'builtin' can only be used in a call to a function with "
+            "the 'nobuiltin' attribute.", I);
+
   visitInstruction(*I);
 }