Sema: Windows/ARM __va_start is not const correct

The `__va_start` intrinsic for Windows ARM does not account for const
correctness when performing a check.  All local qualifiers are ignored
when validating the invocation.  This was exposed by building the swift
stdlib against the Windows 10586 SDK for ARM.  Simply expand out the
check for the two parameters and ignore the qualifiers for the check.

llvm-svn: 314226

1 files changed, 27 insertions, 17 deletions

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 1828dc6c040..962eb5d41a9 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -3943,23 +3943,33 @@ bool Sema::SemaBuiltinVAStartARM(CallExpr *Call) {
   if (checkVAStartIsInVariadicFunction(*this, Func))
     return true;
 
-  const struct {
-    unsigned ArgNo;
-    QualType Type;
-  } ArgumentTypes[] = {
-    { 1, Context.getPointerType(Context.CharTy.withConst()) },
-    { 2, Context.getSizeType() },
-  };
-
-  for (const auto &AT : ArgumentTypes) {
-    const Expr *Arg = Call->getArg(AT.ArgNo)->IgnoreParens();
-    if (Arg->getType().getCanonicalType() == AT.Type.getCanonicalType())
-      continue;
-    Diag(Arg->getLocStart(), diag::err_typecheck_convert_incompatible)
-      << Arg->getType() << AT.Type << 1 /* different class */
-      << 0 /* qualifier difference */ << 3 /* parameter mismatch */
-      << AT.ArgNo + 1 << Arg->getType() << AT.Type;
-  }
+  // __va_start on Windows does not validate the parameter qualifiers
+
+  const Expr *Arg1 = Call->getArg(1)->IgnoreParens();
+  const Type *Arg1Ty = Arg1->getType().getCanonicalType().getTypePtr();
+
+  const Expr *Arg2 = Call->getArg(2)->IgnoreParens();
+  const Type *Arg2Ty = Arg2->getType().getCanonicalType().getTypePtr();
+
+  const QualType &ConstCharPtrTy =
+      Context.getPointerType(Context.CharTy.withConst());
+  if (!Arg1Ty->isPointerType() ||
+      Arg1Ty->getPointeeType().withoutLocalFastQualifiers() != Context.CharTy)
+    Diag(Arg1->getLocStart(), diag::err_typecheck_convert_incompatible)
+        << Arg1->getType() << ConstCharPtrTy
+        << 1 /* different class */
+        << 0 /* qualifier difference */
+        << 3 /* parameter mismatch */
+        << 2 << Arg1->getType() << ConstCharPtrTy;
+
+  const QualType SizeTy = Context.getSizeType();
+  if (Arg2Ty->getCanonicalTypeInternal().withoutLocalFastQualifiers() != SizeTy)
+    Diag(Arg2->getLocStart(), diag::err_typecheck_convert_incompatible)
+        << Arg2->getType() << SizeTy
+        << 1 /* different class */
+        << 0 /* qualifier difference */
+        << 3 /* parameter mismatch */
+        << 3 << Arg2->getType() << SizeTy;
 
   return false;
 }