From 97c853a4e54c6a3ef952a036dd0ece34753732ce Mon Sep 17 00:00:00 2001
From: Shuhei Kadowaki <40514306+aviatesk@users.noreply.github.com>
Date: Wed, 31 Aug 2022 10:52:48 +0900
Subject: [PATCH] `AbstractInterpreter`: allow overload of `type_annotate!`
 (#46554)

So that external `AbstractInterpreter`s observe the DCE on type-inferred
code based on reachability analysis of abstract interpretation.
This is especially useful for Cthulhu to show collected remarks layered
on DCE-ed `CodeInfo` object.
---
 base/compiler/typeinfer.jl | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/base/compiler/typeinfer.jl b/base/compiler/typeinfer.jl
index 77fab9d73d1f8..204fa2b96aae7 100644
--- a/base/compiler/typeinfer.jl
+++ b/base/compiler/typeinfer.jl
@@ -539,7 +539,8 @@ function finish(me::InferenceState, interp::AbstractInterpreter)
         # annotate fulltree with type information,
         # either because we are the outermost code, or we might use this later
         doopt = (me.cached || me.parent !== nothing)
-        recompute_cfg = type_annotate!(me, doopt)
+        changemap = type_annotate!(interp, me, doopt)
+        recompute_cfg = changemap !== nothing
         if doopt && may_optimize(interp)
             me.result.src = OptimizationState(me, OptimizationParams(interp), interp, recompute_cfg)
         else
@@ -690,7 +691,7 @@ function find_dominating_assignment(id::Int, idx::Int, sv::InferenceState)
 end
 
 # annotate types of all symbols in AST
-function type_annotate!(sv::InferenceState, run_optimizer::Bool)
+function type_annotate!(interp::AbstractInterpreter, sv::InferenceState, run_optimizer::Bool)
     # compute the required type for each slot
     # to hold all of the items assigned into it
     record_slot_assign!(sv)
@@ -767,9 +768,9 @@ function type_annotate!(sv::InferenceState, run_optimizer::Bool)
         deleteat!(stmt_info, inds)
         deleteat!(ssaflags, inds)
         renumber_ir_elements!(body, changemap)
-        return true
+        return changemap
     else
-        return false
+        return nothing
     end
 end