Support creating IR from scratch

src/reflection/dynamo.jl

@@ -21,6 +21,9 @@ function fallthrough(args...)
        Expr(:call, [:(args[$i]) for i = 1:length(args)]...))
 end
 
+# Used only for its CodeInfo
+dummy(args...) = nothing
+
 function dynamo(f, args...)
   try
     ir = transform(f, args...)::Union{IR,Expr,Nothing}
@@ -29,10 +32,16 @@ function dynamo(f, args...)
   end
   ir isa Expr && return ir
   ir == nothing && return fallthrough(args...)
-  m = ir.meta::Meta
-  ir = varargs!(m, ir)
-  argnames!(m, :args)
-  _self = splicearg!(m, ir, Symbol("#self#"))
+  if ir.meta isa Meta
+    m = ir.meta
+    ir = varargs!(m, ir)
+    argnames!(m, :args)
+    pushfirst!(m.code.slotnames, Symbol("#self#"))
+  else
+    m = @meta dummy(1)
+    m.code.method_for_inference_limit_heuristics = nothing
+  end
+  _self = splicearg!(ir)
   prewalk!(x -> x === self ? _self : x, ir)
   return update!(m.code, ir)
 end

src/reflection/utils.jl

@@ -97,13 +97,12 @@ function varargs!(meta, ir::IR, n = 0)
 end
 
 # TODO this is hacky and leaves `ir.defs` incorrect
-function splicearg!(meta, ir::IR, name)
+function splicearg!(ir::IR)
   args = arguments(ir)
   push!(ir.defs, (1, -1))
   arg = var(length(ir.defs))
   pushfirst!(args, arg)
   pushfirst!(ir.blocks[1].argtypes, Any)
-  pushfirst!(meta.code.slotnames, name)
   return arg
 end
 

test/compiler.jl

@@ -141,3 +141,13 @@ ir[var(8)] = xcall(:+, var(5), var(2))
 mul = func(ir)
 
 @test mul(nothing, 10, 3) == 31
+
+@dynamo function ir_add(_, _)
+  ir = IR()
+  args = argument!(ir)
+  x = push!(ir, xcall(:getindex, args, 1))
+  y = push!(ir, xcall(:getindex, args, 2))
+  return!(ir, xcall(:+, x, y))
+end
+
+@test ir_add(5, 2) == 7