From a18fff4ca7042b2960f8717c3c80a5d2683f137c Mon Sep 17 00:00:00 2001
From: Jameson Nash <vtjnash@gmail.com>
Date: Tue, 5 Mar 2019 12:26:35 -0500
Subject: [PATCH] avoid some internal methods and invalid objects

---
 src/JuliaInterpreter.jl | 18 +++++++++---------
 src/localmethtable.jl   | 22 +++++++++++++---------
 2 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/src/JuliaInterpreter.jl b/src/JuliaInterpreter.jl
index b9f26da47dc47..b528d8c7d904f 100644
--- a/src/JuliaInterpreter.jl
+++ b/src/JuliaInterpreter.jl
@@ -347,9 +347,15 @@ function prepare_args(@nospecialize(f), allargs, kwargs)
     return f, allargs
 end
 
+if VERSION < v"1.2-" || !isdefined(Core.Compiler, :specialize_method)
+    specialize_method(method::Method, @nospecialize(atypes), sparams::SimpleVector) =
+        Core.Compiler.code_for_method(method, atypes, sparams, typemax(UInt))
+else
+    const specialize_method = Core.Compiler.specialize_method
+end
+
 function prepare_framecode(method::Method, argtypes; enter_generated=false)
     sig = method.sig
-    isa(method, TypeMapEntry) && (method = method.func)
     if method.module == Core.Compiler || method.module == Base.Threads || method ∈ compiled_methods
         return Compiled()
     end
@@ -367,7 +373,7 @@ function prepare_framecode(method::Method, argtypes; enter_generated=false)
             # If we're stepping into a staged function, we need to use
             # the specialization, rather than stepping through the
             # unspecialized method.
-            code = Core.Compiler.get_staged(Core.Compiler.code_for_method(method, argtypes, lenv, typemax(UInt), false))
+            code = Core.Compiler.get_staged(specialize_method(method, argtypes, lenv))
             code === nothing && return nothing
             generator = false
         else
@@ -645,13 +651,7 @@ function determine_method_for_expr(expr; enter_generated = false)
     return prepare_call(f, allargs; enter_generated=enter_generated)
 end
 
-function get_source(meth)
-    if isa(meth.source, Array{UInt8,1})
-        return ccall(:jl_uncompress_ast, Any, (Any, Any), meth, meth.source)
-    else
-        return meth.source
-    end
-end
+get_source(meth) = Base.uncompressed_ast(meth)
 
 function get_source(g::GeneratedFunctionStub)
     b = g(g.argnames...)
diff --git a/src/localmethtable.jl b/src/localmethtable.jl
index 244ec68c38a03..9a9b76ab50466 100644
--- a/src/localmethtable.jl
+++ b/src/localmethtable.jl
@@ -1,5 +1,10 @@
 const max_methods = 4  # maximum number of MethodInstances tracked for a particular :call statement
 
+struct FrameInstance
+    framecode::JuliaFrameCode
+    sparam_vals::SimpleVector
+end
+
 """
     framecode, lenv = get_call_framecode(fargs, parentframe::JuliaFrameCode, idx::Int)
 
@@ -34,9 +39,8 @@ function get_call_framecode(fargs, parentframe::JuliaFrameCode, idx::Int)
                         tmeprev.next = tme.next
                         tme.next = tme1
                     end
-                    # The framecode is stashed in the `inferred` field of the MethodInstance
-                    mi = tme.func::MethodInstance
-                    return mi.inferred::JuliaFrameCode, mi.sparam_vals
+                    mi = tme.func::FrameInstance
+                    return mi.framecode, mi.sparam_vals
                 end
             end
             depth += 1
@@ -53,17 +57,17 @@ function get_call_framecode(fargs, parentframe::JuliaFrameCode, idx::Int)
     isa(ret, Compiled) && return ret, nothing
     framecode, args, env, argtypes = ret
     # Store the results of the method lookup in the local method table
+    mi = FrameInstance(framecode, env)
+    # it's sort of odd to call this a TypeMapEntry, then set most of the fields incorrectly
+    # but since we're just using it as a linked list, it's probably ok
     tme = ccall(:jl_new_struct_uninit, Any, (Any,), TypeMapEntry)::TypeMapEntry
-    tme.func = mi = ccall(:jl_new_struct_uninit, Any, (Any,), MethodInstance)::MethodInstance
-    tme.sig = mi.specTypes = argtypes
+    tme.func = mi
+    tme.simplesig = nothing
+    tme.sig = argtypes
     tme.isleafsig = true
     tme.issimplesig = false
     method = framecode.scope::Method
     tme.va = method.isva
-    mi.def = method
-    mi.rettype = Any
-    mi.sparam_vals = env
-    mi.inferred = framecode   # a slight abuse, but not insane
     if isassigned(parentframe.methodtables, idx)
         tme.next = parentframe.methodtables[idx]
         # Drop the oldest tme, if necessary