Add Sema support for __builtin_setjmp/__builtin_longjmp. The primary

reason for adding these is to error out in CodeGen when trying to generate
them instead of silently emitting a call to a non-existent function.

(Note that it is not valid to lower these to setjmp/longjmp; in addition 
to that lowering being different from the intent, setjmp and longjmp 
require a larger buffer.)

llvm-svn: 70658

clang/include/clang/AST/Builtins.def

@@ -164,6 +164,8 @@ BUILTIN(__builtin_strstr, "c*cC*cC*", "nF")
 BUILTIN(__builtin_return_address, "v*Ui", "n")
 BUILTIN(__builtin_frame_address, "v*Ui", "n")
 BUILTIN(__builtin_flt_rounds, "i", "nc")
+BUILTIN(__builtin_setjmp, "iv**", "")
+BUILTIN(__builtin_longjmp, "vv**i", "")
 
 // GCC Object size checking builtins
 BUILTIN(__builtin_object_size, "zv*i", "n")

clang/lib/Sema/Sema.h

@@ -2566,6 +2566,7 @@ private:
   Action::OwningExprResult SemaBuiltinShuffleVector(CallExpr *TheCall);
   bool SemaBuiltinPrefetch(CallExpr *TheCall); 
   bool SemaBuiltinObjectSize(CallExpr *TheCall);
+  bool SemaBuiltinLongjmp(CallExpr *TheCall);
   bool SemaCheckStringLiteral(const Expr *E, const CallExpr *TheCall,
                               bool HasVAListArg, unsigned format_idx,
                               unsigned firstDataArg);

clang/lib/Sema/SemaChecking.cpp

@@ -134,6 +134,9 @@ Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall) {
   case Builtin::BI__builtin_object_size:
     if (SemaBuiltinObjectSize(TheCall))
       return ExprError();
+  case Builtin::BI__builtin_longjmp:
+    if (SemaBuiltinLongjmp(TheCall))
+      return ExprError();
   }
 
   // FIXME: This mechanism should be abstracted to be less fragile and
@@ -424,6 +427,18 @@ bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) {
   return false;
 }
 
+/// SemaBuiltinObjectSize - Handle __builtin_longjmp(void *env[5], int val).
+/// This checks that val is a constant 1.
+bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) {
+  Expr *Arg = TheCall->getArg(1);
+  llvm::APSInt Result(32);
+  if (!Arg->isIntegerConstantExpr(Result, Context) || Result != 1)
+    return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val)
+             << SourceRange(Arg->getLocStart(), Arg->getLocEnd());
+
+  return false;
+}
+
 // Handle i > 1 ? "x" : "y", recursivelly
 bool Sema::SemaCheckStringLiteral(const Expr *E, const CallExpr *TheCall,
                                   bool HasVAListArg,