Fix completely bogus types for some builtins:

 * In C++, never create a FunctionNoProtoType for a builtin (fixes C++1z
   crasher from r289754).

 * Fix type of __sync_synchronize to be a no-parameter function rather than a
   varargs function. This matches GCC.

 * Fix type of vfprintf to match its actual type. We gave it a wrong type due
   to PR4290 (apparently autoconf generates invalid code and expects compilers
   to choke it down or it miscompiles the program; the relevant error in clang
   was downgraded to a warning in r122744 to fix other occurrences of this
   autoconf brokenness, so we don't need this workaround any more).

 * Turn off vararg argument checking for __noop, since it's not *really* a
   varargs function. Alternatively we could add custom type checking for it
   and synthesize parameter types matching the actual arguments in each call,
   but that seemed like overkill.

llvm-svn: 290146

1 files changed, 7 insertions, 6 deletions

diff --git a/clang/lib/Sema/SemaExceptionSpec.cpp b/clang/lib/Sema/SemaExceptionSpec.cpp
index 781f78018b4..2ac2aca6f66 100644
--- a/clang/lib/Sema/SemaExceptionSpec.cpp
+++ b/clang/lib/Sema/SemaExceptionSpec.cpp
@@ -288,14 +288,15 @@ bool Sema::CheckEquivalentExceptionSpec(FunctionDecl *Old, FunctionDecl *New) {
   // The new function declaration is only missing an empty exception
   // specification "throw()". If the throw() specification came from a
   // function in a system header that has C linkage, just add an empty
-  // exception specification to the "new" declaration. This is an
-  // egregious workaround for glibc, which adds throw() specifications
-  // to many libc functions as an optimization. Unfortunately, that
-  // optimization isn't permitted by the C++ standard, so we're forced
-  // to work around it here.
+  // exception specification to the "new" declaration. Note that C library
+  // implementations are permitted to add these nothrow exception
+  // specifications.
+  //
+  // Likewise if the old function is a builtin.
   if (MissingEmptyExceptionSpecification && NewProto &&
       (Old->getLocation().isInvalid() ||
-       Context.getSourceManager().isInSystemHeader(Old->getLocation())) &&
+       Context.getSourceManager().isInSystemHeader(Old->getLocation()) ||
+       Old->getBuiltinID()) &&
       Old->isExternC()) {
     New->setType(Context.getFunctionType(
         NewProto->getReturnType(), NewProto->getParamTypes(),