From 510d2f97ad2e185f28f04f29d573b8f17dec30a6 Mon Sep 17 00:00:00 2001
From: Shuhei Kadowaki <aviatesk@gmail.com>
Date: Wed, 15 Sep 2021 19:37:32 +0900
Subject: [PATCH] optimizer: fix #42258, make sure to set `ssaflags` correctly

Essentially, this PR adds missing `ssaflags` deletion of `type_annotate!`.
Built on top of #42260.
---
 base/compiler/optimize.jl       |  2 +-
 base/compiler/ssair/legacy.jl   |  6 ++++--
 base/compiler/ssair/slot2ssa.jl |  9 +++++----
 base/compiler/typeinfer.jl      |  1 +
 test/compiler/ssair.jl          | 17 +++++++++++++++++
 5 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/base/compiler/optimize.jl b/base/compiler/optimize.jl
index 5acfd22eb995a2..02ee5cdc9ecc11 100644
--- a/base/compiler/optimize.jl
+++ b/base/compiler/optimize.jl
@@ -85,7 +85,7 @@ mutable struct OptimizationState
         if nssavalues isa Int
             src.ssavaluetypes = Any[ Any for i = 1:nssavalues ]
         else
-            nssavalues = length(src.ssavaluetypes)
+            nssavalues = length(src.ssavaluetypes::Vector{Any})
         end
         nslots = length(src.slotflags)
         slottypes = src.slottypes
diff --git a/base/compiler/ssair/legacy.jl b/base/compiler/ssair/legacy.jl
index 4d2bafc2f38d9b..e393b2bff049c6 100644
--- a/base/compiler/ssair/legacy.jl
+++ b/base/compiler/ssair/legacy.jl
@@ -29,9 +29,11 @@ function inflate_ir(ci::CodeInfo, sptypes::Vector{Any}, argtypes::Vector{Any})
             code[i] = stmt
         end
     end
-    ssavaluetypes = ci.ssavaluetypes
     nstmts = length(code)
-    ssavaluetypes = ci.ssavaluetypes isa Vector{Any} ? copy(ci.ssavaluetypes) : Any[ Any for i = 1:(ci.ssavaluetypes::Int) ]
+    ssavaluetypes = let
+        ssavaluetypes = ci.ssavaluetypes
+        ssavaluetypes isa Vector{Any} ? copy(ssavaluetypes) : Any[ Any for i = 1:(ssavaluetypes::Int) ]
+    end
     stmts = InstructionStream(code, ssavaluetypes, Any[nothing for i = 1:nstmts], copy(ci.codelocs), copy(ci.ssaflags))
     ir = IRCode(stmts, cfg, collect(LineInfoNode, ci.linetable), argtypes, Any[], sptypes)
     return ir
diff --git a/base/compiler/ssair/slot2ssa.jl b/base/compiler/ssair/slot2ssa.jl
index 656df9b17e4c4a..846ebde4c0bb11 100644
--- a/base/compiler/ssair/slot2ssa.jl
+++ b/base/compiler/ssair/slot2ssa.jl
@@ -177,13 +177,14 @@ function strip_trailing_junk!(ci::CodeInfo, code::Vector{Any}, info::Vector{Any}
     # Remove `nothing`s at the end, we don't handle them well
     # (we expect the last instruction to be a terminator)
     ssavaluetypes = ci.ssavaluetypes::Vector{Any}
+    (; codelocs, ssaflags) = ci
     for i = length(code):-1:1
         if code[i] !== nothing
             resize!(code, i)
             resize!(ssavaluetypes, i)
-            resize!(ci.codelocs, i)
+            resize!(codelocs, i)
             resize!(info, i)
-            resize!(ci.ssaflags, i)
+            resize!(ssaflags, i)
             break
         end
     end
@@ -193,9 +194,9 @@ function strip_trailing_junk!(ci::CodeInfo, code::Vector{Any}, info::Vector{Any}
     if !isa(term, GotoIfNot) && !isa(term, GotoNode) && !isa(term, ReturnNode)
         push!(code, ReturnNode())
         push!(ssavaluetypes, Union{})
-        push!(ci.codelocs, 0)
+        push!(codelocs, 0)
         push!(info, nothing)
-        push!(ci.ssaflags, IR_FLAG_NULL)
+        push!(ssaflags, IR_FLAG_NULL)
     end
     nothing
 end
diff --git a/base/compiler/typeinfer.jl b/base/compiler/typeinfer.jl
index c3b7c4dc3a3d0d..9d12c890d6be6c 100644
--- a/base/compiler/typeinfer.jl
+++ b/base/compiler/typeinfer.jl
@@ -666,6 +666,7 @@ function type_annotate!(sv::InferenceState, run_optimizer::Bool)
                 deleteat!(ssavaluetypes, i)
                 deleteat!(src.codelocs, i)
                 deleteat!(sv.stmt_info, i)
+                deleteat!(src.ssaflags, i)
                 nexpr -= 1
                 changemap[oldidx] = -1
                 continue
diff --git a/test/compiler/ssair.jl b/test/compiler/ssair.jl
index 17a0753eddc640..e716730b86a390 100644
--- a/test/compiler/ssair.jl
+++ b/test/compiler/ssair.jl
@@ -314,3 +314,20 @@ end
 # Issue #41975 - SSA conversion drops type check
 f_if_typecheck() = (if nothing; end; unsafe_load(Ptr{Int}(0)))
 @test_throws TypeError f_if_typecheck()
+
+let # https://github.com/JuliaLang/julia/issues/42258
+    # XXX this test case is not so robust against the future changes within `Core.Compiler`
+    ci, = only(code_typed(Core.Compiler.setindex!, (Core.Compiler.UseRef,Core.Compiler.NewSSAValue); optimize=true))
+    idx = filter(1:length(ci.code)) do i
+        stmt = ci.code[i]
+        if Meta.isexpr(stmt, :call)
+            t = Core.Compiler.argextype(stmt.args[1], ci, Any[])
+            ft = Core.Compiler.widenconst(t)
+            return ft === typeof(BoundsError) || ft === typeof(throw)
+        end
+        return false
+    end
+    @test all(ci.ssaflags[idx]) do flag
+        flag & Core.Compiler.IR_FLAG_THROW_BLOCK ≠ 0
+    end
+end