commit 836de6babb7846e08476988c8b2cf3ced0b09a1e
author Richard Smith <richard-llvm@metafoo.co.uk> Mon Dec 19 23:59:34 2016 +0000
committer Richard Smith <richard-llvm@metafoo.co.uk> Mon Dec 19 23:59:34 2016 +0000
tree eec032705d2c271fe0d7abbc5e71f9b40a9303f8
parent ebfc2f90d0a12eac664e5978de905e09ca483b2f

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

clang/lib/Sema/SemaChecking.cpp

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 450e278..9c90295 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -2448,7 +2448,9 @@
 
   // Refuse POD arguments that weren't caught by the format string
   // checks above.
-  if (CallType != VariadicDoesNotApply) {
+  auto *FD = dyn_cast_or_null<FunctionDecl>(FDecl);
+  if (CallType != VariadicDoesNotApply &&
+      (!FD || FD->getBuiltinID() != Builtin::BI__noop)) {
     unsigned NumParams = Proto ? Proto->getNumParams()
                        : FDecl && isa<FunctionDecl>(FDecl)
                            ? cast<FunctionDecl>(FDecl)->getNumParams()

clang/lib/Sema/SemaExceptionSpec.cpp

diff --git a/clang/lib/Sema/SemaExceptionSpec.cpp b/clang/lib/Sema/SemaExceptionSpec.cpp
index 781f780..2ac2aca 100644
--- a/clang/lib/Sema/SemaExceptionSpec.cpp
+++ b/clang/lib/Sema/SemaExceptionSpec.cpp
@@ -288,14 +288,15 @@
   // 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(),