fix a performance regression due to the GlobalRef change (7908246)

this was mostly evident in the go_benchmark perf test

also strip empty metadata nodes from inlined functions to save space

base/inference.jl

@@ -1974,17 +1974,6 @@ function exprtype(x::ANY, sv::StaticVarInfo)
     end
 end
 
-function without_linenums(a::Array{Any,1})
-    l = []
-    for x in a
-        if (isa(x,Expr) && is(x.head,:line)) || isa(x,LineNumberNode)
-        else
-            push!(l, x)
-        end
-    end
-    l
-end
-
 # known affect-free calls (also effect-free)
 const _pure_builtins = Any[tuple, svec, fieldtype, apply_type, is, isa, typeof, typeassert]
 
@@ -2032,6 +2021,10 @@ function effect_free(e::ANY, sv, allow_volatile::Bool)
         isa(e,TopNode) || isa(e,QuoteNode) || isa(e,Type) || isa(e,Tuple)
         return true
     end
+    if isa(e,GlobalRef)
+        allow_volatile && return true
+        return isconst(e.mod, e.name)
+    end
     if isconstantfunc(e, sv) !== false
         return true
     end
@@ -2248,7 +2241,8 @@ function inlineable(f::ANY, e::Expr, atype::ANY, sv::StaticVarInfo, enclosing_as
     end
 
     body = Expr(:block)
-    body.args = without_linenums(ast.args[3].args)::Array{Any,1}
+    body.args = filter(x->!((isa(x,Expr) && is(x.head,:line)) || isa(x,LineNumberNode)),
+                       ast.args[3].args::Array{Any,1})
     cost::Int = 1000
     if incompletematch
         cost *= 4
@@ -2284,6 +2278,9 @@ function inlineable(f::ANY, e::Expr, atype::ANY, sv::StaticVarInfo, enclosing_as
             return NF
         end
     end
+    # remove empty meta
+    body.args = filter(x->!(isa(x,Expr) && x.head === :meta && isempty(x.args)),
+                       body.args)
 
     spnames = Any[ sp[i].name for i=1:2:length(sp) ]
     enc_vinflist = enclosing_ast.args[2][1]::Array{Any,1}

src/codegen.cpp

@@ -1572,7 +1572,7 @@ static void mark_volatile_vars(jl_array_t *stmts, std::map<jl_sym_t*,jl_varinfo_
 
 static bool expr_is_symbol(jl_value_t *e)
 {
-    return (jl_is_symbol(e) || jl_is_symbolnode(e) || jl_is_topnode(e));
+    return (jl_is_symbol(e) || jl_is_symbolnode(e) || jl_is_topnode(e) || jl_is_globalref(e));
 }
 
 // a very simple, conservative escape analysis that is sufficient for
@@ -1746,7 +1746,8 @@ static bool is_stable_expr(jl_value_t *ex, jl_codectx_t *ctx)
 static bool might_need_root(jl_value_t *ex)
 {
     return (!jl_is_symbol(ex) && !jl_is_symbolnode(ex) && !jl_is_gensym(ex) &&
-            !jl_is_bool(ex) && !jl_is_quotenode(ex) && !jl_is_byte_string(ex));
+            !jl_is_bool(ex) && !jl_is_quotenode(ex) && !jl_is_byte_string(ex) &&
+            !jl_is_globalref(ex));
 }
 
 static Value *emit_boxed_rooted(jl_value_t *e, jl_codectx_t *ctx)
@@ -4379,8 +4380,7 @@ static Function *emit_function(jl_lambda_info_t *lam)
                 vi.hasGCRoot = false;
                 continue;
             }
-            if (vi.isSA && !vi.isVolatile &&
-                    !vi.isCaptured && !vi.usedUndef) {
+            if (vi.isSA && !vi.isVolatile && !vi.isCaptured && !vi.usedUndef) {
                 vi.hasGCRoot = false; // so far...
             }
             else {