throw exceptions with arguments without creating a GC frame

base/base.jl

@@ -48,6 +48,10 @@ convert{T}(::Type{Tuple{Vararg{T}}}, x::Tuple) = cnvt_all(T, x...)
 cnvt_all(T) = ()
 cnvt_all(T, x, rest...) = tuple(convert(T,x), cnvt_all(T, rest...)...)
 
+macro _meta(args...)
+    Expr(:meta, args...)
+end
+
 macro generated(f)
     isa(f, Expr) || error("invalid syntax; @generated must be used with a function definition")
     if is(f.head, :function) || isdefined(:length) && is(f.head, :(=)) && length(f.args) == 2 && f.args[1].head == :call
@@ -159,6 +163,16 @@ type AssertionError <: Exception
     AssertionError(msg) = new(msg)
 end
 
+throw_with_args(typ::ANY) = (@_meta(noinline); throw(typ()))
+throw_with_args(typ::ANY, arg1) = (@_meta(noinline); throw(typ(arg1)))
+throw_with_args(typ::ANY, arg1, arg2) =
+    (@_meta(noinline); throw(typ(arg1, arg2)))
+throw_with_args(typ::ANY, arg1, arg2, arg3) =
+    (@_meta(noinline); throw(typ(arg1, arg2, arg3)))
+throw_with_args(typ::ANY, arg1, arg2, arg3, arg4) =
+    (@_meta(noinline); throw(typ(arg1, arg2, arg3, arg4)))
+throw_with_args(typ::ANY, args...) = throw(typ(args...))
+
 # For passing constants through type inference
 immutable Val{T}
 end

base/inference.jl

@@ -2200,6 +2200,20 @@ function inlineable(f::ANY, e::Expr, atype::ANY, sv::StaticVarInfo, enclosing_as
             end
         end
     end
+    # Special case for throw. Use push the construction of the exception into
+    # a helper function to avoid creating a GC frame. This hack can be removed
+    # when codegen is smarter on inserting GC frames or if creating GC frames
+    # no longer affect performance.
+    if is(f, throw) && length(atypes) == 1 && isa(argexprs[1], Expr)
+        throw_expr::Expr = argexprs[1]
+        throw_args = throw_expr.args
+        if !is(throw_expr.head, :new)
+            return NF
+        end
+        expr = Expr(:call, TopNode(:throw_with_args), throw_args...)
+        expr.typ = Bottom
+        return (expr, ())
+    end
     if isa(f,IntrinsicFunction)
         return NF
     end