use the CFG selection algorithm implememted in LCU v3.0.2 (#662)

aviatesk · Sep 11, 2024 · 321fbd5 · 321fbd5
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diff --git a/Project.toml b/Project.toml
@@ -32,7 +32,7 @@ InteractiveUtils = "1.10"
 JuliaInterpreter = "0.9.36"
 Libdl = "1.10"
 Logging = "1.10"
-LoweredCodeUtils = "3"
+LoweredCodeUtils = "3.0.2"
 MacroTools = "0.5.6"
 Pkg = "1.10"
 PrecompileTools = "1"

diff --git a/src/JET.jl b/src/JET.jl
@@ -36,11 +36,11 @@ using Core: Builtin, IntrinsicFunction, Intrinsics, SimpleVector, svec
 using Core.IR
 
 using .CC: @nospecs, ⊑,
-    AbstractInterpreter, AbstractLattice, ArgInfo, BasicBlock, Bottom, CFG, CachedMethodTable,
-    CallMeta, ConstCallInfo, InferenceParams, InferenceResult, InferenceState,
-    InternalMethodTable, InvokeCallInfo, MethodCallResult, MethodMatchInfo, MethodMatches,
-    NOT_FOUND, OptimizationState, OptimizationParams, OverlayMethodTable, StmtInfo,
-    UnionSplitInfo, UnionSplitMethodMatches, VarState, VarTable, WorldRange, WorldView,
+    AbstractInterpreter, AbstractLattice, ArgInfo, Bottom, CFG, CachedMethodTable, CallMeta,
+    ConstCallInfo, InferenceParams, InferenceResult, InferenceState, InternalMethodTable,
+    InvokeCallInfo, MethodCallResult, MethodMatchInfo, MethodMatches, NOT_FOUND,
+    OptimizationState, OptimizationParams, OverlayMethodTable, StmtInfo, UnionSplitInfo,
+    UnionSplitMethodMatches, VarState, VarTable, WorldRange, WorldView,
     argextype, argtype_by_index, argtypes_to_type, compute_basic_blocks,
     construct_postdomtree, hasintersect, ignorelimited, instanceof_tfunc, istopfunction,
     nearest_common_dominator, singleton_type, slot_id, specialize_method, tmeet, tmerge,

diff --git a/src/toplevel/virtualprocess.jl b/src/toplevel/virtualprocess.jl
@@ -1199,92 +1199,6 @@ function is_known_getproperty(@nospecialize(stmt), func::Symbol, stmts::Vector{A
     return false
 end
 
-# The goal of this function is to request concretization of the minimal necessary control
-# flow to evaluate statements whose concretization have already been requested.
-# The basic algorithm is based on what was proposed in [^Wei84]. If there is even one active
-# block in the blocks reachable from a conditional branch up to its successors' nearest
-# common post-dominator (referred to as 𝑰𝑵𝑭𝑳 in the paper), it is necessary to follow
-# that conditional branch and execute the code. Otherwise, execution can be short-circuited
-# from the conditional branch to the nearest common post-dominator.
-#
-# COMBAK: It is important to note that in Julia's intermediate code representation (`CodeInfo`),
-# "short-circuiting" a specific code region is not a simple task. Simply ignoring the path
-# to the post-dominator does not guarantee fall-through to the post-dominator. Therefore,
-# a more careful implementation is required for this aspect.
-#
-# [Wei84]: M. Weiser, "Program Slicing," IEEE Transactions on Software Engineering, 10, pages 352-357, July 1984.
-function add_control_flow!(concretize::BitVector, src::CodeInfo, cfg::CFG, postdomtree)
-    local changed::Bool = false
-    function mark_concretize!(idx::Int)
-        if !concretize[idx]
-            changed |= concretize[idx] = true
-            return true
-        end
-        return false
-    end
-    for bbidx = 1:length(cfg.blocks) # forward traversal
-        bb = cfg.blocks[bbidx]
-        nsuccs = length(bb.succs)
-        if nsuccs == 0
-            continue
-        elseif nsuccs == 1
-            continue # leave a fall-through terminator unmarked: `GotoNode`s are marked later
-        elseif nsuccs == 2
-            termidx = bb.stmts[end]
-            @assert is_conditional_terminator(src.code[termidx]) "invalid IR"
-            if is_conditional_block_active(concretize, bb, cfg, postdomtree)
-                mark_concretize!(termidx)
-            else
-                # fall-through to the post dominator block (by short-circuiting all statements between)
-            end
-        end
-    end
-    return changed
-end
-
-is_conditional_terminator(@nospecialize stmt) = stmt isa GotoIfNot ||
-    (@static @isdefined(EnterNode) ? stmt isa EnterNode : isexpr(stmt, :enter))
-
-function is_conditional_block_active(concretize::BitVector, bb::BasicBlock, cfg::CFG, postdomtree)
-    return visit_𝑰𝑵𝑭𝑳_blocks(bb, cfg, postdomtree) do postdominator::Int, 𝑰𝑵𝑭𝑳::BitSet
-        for blk in 𝑰𝑵𝑭𝑳
-            if blk == postdominator
-                continue # skip the post-dominator block and continue to a next infl block
-            end
-            if any(@view concretize[cfg.blocks[blk].stmts])
-                return true
-            end
-        end
-        return false
-    end
-end
-
-function visit_𝑰𝑵𝑭𝑳_blocks(func, bb::BasicBlock, cfg::CFG, postdomtree)
-    succ1, succ2 = bb.succs
-    postdominator = nearest_common_dominator(postdomtree, succ1, succ2)
-    𝑰𝑵𝑭𝑳 = reachable_blocks(cfg, succ1, postdominator) ∪ reachable_blocks(cfg, succ2, postdominator)
-    return func(postdominator, 𝑰𝑵𝑭𝑳)
-end
-
-function reachable_blocks(cfg::CFG, from_bb::Int, to_bb::Int)
-    worklist = Int[from_bb]
-    visited = BitSet(from_bb)
-    if to_bb == from_bb
-        return visited
-    end
-    push!(visited, to_bb)
-    function visit!(bb::Int)
-        if bb ∉ visited
-            push!(visited, bb)
-            push!(worklist, bb)
-        end
-    end
-    while !isempty(worklist)
-        foreach(visit!, cfg.blocks[pop!(worklist)].succs)
-    end
-    return visited
-end
-
 function add_required_inplace!(concretize::BitVector, src::CodeInfo, edges, cl)
     changed = false
     for i = 1:length(src.code)
@@ -1330,7 +1244,7 @@ function select_dependencies!(concretize::BitVector, src::CodeInfo, edges, cl)
     while true
         changed = false
 
-        # Discover Dtruct/method definitions at the beginning,
+        # Discover struct/method definitions at the beginning,
         # and propagate the definition requirements by tracking SSA precedessors.
         # (TODO maybe hoist this out of the loop?)
         changed |= LoweredCodeUtils.add_typedefs!(concretize, src, edges, typedefs, ())
@@ -1349,65 +1263,18 @@ function select_dependencies!(concretize::BitVector, src::CodeInfo, edges, cl)
         changed |= add_ssa_preds!(concretize, src, edges, ())
 
         # Mark necessary control flows.
-        changed |= add_control_flow!(concretize, src, cfg, postdomtree)
+        changed |= LoweredCodeUtils.add_control_flow!(concretize, src, cfg, postdomtree)
         changed |= add_ssa_preds!(concretize, src, edges, ())
 
         changed || break
     end
 
     # now mark the active goto nodes
-    add_active_gotos!(concretize, src, cfg, postdomtree)
+    LoweredCodeUtils.add_active_gotos!(concretize, src, cfg, postdomtree)
 
     nothing
 end
 
-function add_active_gotos!(concretize::BitVector, src::CodeInfo, cfg::CFG, postdomtree)
-    dead_blocks = compute_dead_blocks(concretize, src, cfg, postdomtree)
-    changed = false
-    for bbidx = 1:length(cfg.blocks)
-        if bbidx ∉ dead_blocks
-            bb = cfg.blocks[bbidx]
-            nsuccs = length(bb.succs)
-            if nsuccs == 1
-                termidx = bb.stmts[end]
-                if src.code[termidx] isa GotoNode
-                    changed |= concretize[termidx] = true
-                end
-            end
-        end
-    end
-    return changed
-end
-
-# find dead blocks using the same approach as `add_control_flow!`, for the converged `concretize`
-function compute_dead_blocks(concretize::BitVector, src::CodeInfo, cfg::CFG, postdomtree)
-    dead_blocks = BitSet()
-    for bbidx = 1:length(cfg.blocks)
-        bb = cfg.blocks[bbidx]
-        nsuccs = length(bb.succs)
-        if nsuccs == 2
-            termidx = bb.stmts[end]
-            @assert is_conditional_terminator(src.code[termidx]) "invalid IR"
-            visit_𝑰𝑵𝑭𝑳_blocks(bb, cfg, postdomtree) do postdominator::Int, 𝑰𝑵𝑭𝑳::BitSet
-                is_𝑰𝑵𝑭𝑳_active = false
-                for blk in 𝑰𝑵𝑭𝑳
-                    if blk == postdominator
-                        continue # skip the post-dominator block and continue to a next infl block
-                    end
-                    if any(@view concretize[cfg.blocks[blk].stmts])
-                        is_𝑰𝑵𝑭𝑳_active |= true
-                        break
-                    end
-                end
-                if !is_𝑰𝑵𝑭𝑳_active
-                    union!(dead_blocks, delete!(𝑰𝑵𝑭𝑳, postdominator))
-                end
-            end
-        end
-    end
-    return dead_blocks
-end
-
 function JuliaInterpreter.step_expr!(interp::ConcreteInterpreter, frame::Frame, @nospecialize(node), istoplevel::Bool)
     @assert istoplevel "ConcreteInterpreter can only work for top-level code"
 

diff --git a/test/toplevel/test_virtualprocess.jl b/test/toplevel/test_virtualprocess.jl
@@ -1781,8 +1781,8 @@ end
     # A more complex test case (xref: https://github.com/JuliaDebug/LoweredCodeUtils.jl/pull/99#issuecomment-2236373067)
     # This test case might seem simple at first glance, but note that `x2` and `a2` are
     # defined at the top level (because of the `begin` at the top).
-    # Since global variable type declarations have been allowed since v1.
-    # 10, a conditional branch that includes `Core.get_binding_type` is generated for
+    # Since global variable type declarations have been allowed since v1.10,
+    # a conditional branch that includes `Core.get_binding_type` is generated for
     # these simple global variable assignments.
     # Specifically, the code is lowered into something like this:
     #     1      1: conditional branching based on `x2`'s binding type