compiler: add flag manipulation utilities (JuliaLang#52269)

Right now, we're checking if a flag exists using bare operations like
`&` and `==`. This works fine, but I think unifying these interfaces
could make our code easier to maintain. So, this commit introduces some
new high-level operators and refactored the code to incorporate them:
- `has_flag(curr::UInt32, flag::UInt32)`
- `has_flag(inst::Instruction, flag::UInt32)`
- `add_flag!(inst::Instruction, flag::UInt32)`
- `sub_flag!(inst::Instruction, flag::UInt32)`

base/compiler/abstractinterpretation.jl

@@ -2705,7 +2705,7 @@ end
 
 function stmt_taints_inbounds_consistency(sv::AbsIntState)
     propagate_inbounds(sv) && return true
-    return (get_curr_ssaflag(sv) & IR_FLAG_INBOUNDS) != 0
+    return has_curr_ssaflag(sv, IR_FLAG_INBOUNDS)
 end
 
 function abstract_eval_statement(interp::AbstractInterpreter, @nospecialize(e), vtypes::VarTable, sv::InferenceState)
@@ -2718,7 +2718,7 @@ function abstract_eval_statement(interp::AbstractInterpreter, @nospecialize(e),
     else
         (; rt, exct, effects) = abstract_eval_statement_expr(interp, e, vtypes, sv)
         if effects.noub === NOUB_IF_NOINBOUNDS
-            if !iszero(get_curr_ssaflag(sv) & IR_FLAG_INBOUNDS)
+            if has_curr_ssaflag(sv, IR_FLAG_INBOUNDS)
                 effects = Effects(effects; noub=ALWAYS_FALSE)
             elseif !propagate_inbounds(sv)
                 # The callee read our inbounds flag, but unless we propagate inbounds,
@@ -3258,7 +3258,7 @@ function typeinf_local(interp::AbstractInterpreter, frame::InferenceState)
             if exct !== Union{}
                 update_exc_bestguess!(exct, frame, ipo_lattice(interp))
             end
-            if (get_curr_ssaflag(frame) & IR_FLAG_NOTHROW) != IR_FLAG_NOTHROW
+            if !has_curr_ssaflag(frame, IR_FLAG_NOTHROW)
                 propagate_to_error_handler!(currstate, frame, 𝕃ᵢ)
             end
             if rt === Bottom

base/compiler/inferencestate.jl

@@ -888,6 +888,9 @@ end
 get_curr_ssaflag(sv::InferenceState) = sv.src.ssaflags[sv.currpc]
 get_curr_ssaflag(sv::IRInterpretationState) = sv.ir.stmts[sv.curridx][:flag]
 
+has_curr_ssaflag(sv::InferenceState, flag::UInt32) = has_flag(sv.src.ssaflags[sv.currpc], flag)
+has_curr_ssaflag(sv::IRInterpretationState, flag::UInt32) = has_flag(sv.ir.stmts[sv.curridx][:flag], flag)
+
 function set_curr_ssaflag!(sv::InferenceState, flag::UInt32, mask::UInt32=typemax(UInt32))
     curr_flag = sv.src.ssaflags[sv.currpc]
     sv.src.ssaflags[sv.currpc] = (curr_flag & ~mask) | flag
@@ -898,10 +901,10 @@ function set_curr_ssaflag!(sv::IRInterpretationState, flag::UInt32, mask::UInt32
 end
 
 add_curr_ssaflag!(sv::InferenceState, flag::UInt32) = sv.src.ssaflags[sv.currpc] |= flag
-add_curr_ssaflag!(sv::IRInterpretationState, flag::UInt32) = sv.ir.stmts[sv.curridx][:flag] |= flag
+add_curr_ssaflag!(sv::IRInterpretationState, flag::UInt32) = add_flag!(sv.ir.stmts[sv.curridx], flag)
 
 sub_curr_ssaflag!(sv::InferenceState, flag::UInt32) = sv.src.ssaflags[sv.currpc] &= ~flag
-sub_curr_ssaflag!(sv::IRInterpretationState, flag::UInt32) = sv.ir.stmts[sv.curridx][:flag] &= ~flag
+sub_curr_ssaflag!(sv::IRInterpretationState, flag::UInt32) = sub_flag!(sv.ir.stmts[sv.curridx], flag)
 
 function merge_effects!(::AbstractInterpreter, caller::InferenceState, effects::Effects)
     if effects.effect_free === EFFECT_FREE_GLOBALLY

base/compiler/optimize.jl

@@ -15,36 +15,38 @@ const SLOT_USEDUNDEF    = 32 # slot has uses that might raise UndefVarError
 
 # NOTE make sure to sync the flag definitions below with julia.h and `jl_code_info_set_ir` in method.c
 
-const IR_FLAG_NULL        = UInt32(0)
+const IR_FLAG_NULL        = zero(UInt32)
 # This statement is marked as @inbounds by user.
 # Ff replaced by inlining, any contained boundschecks may be removed.
-const IR_FLAG_INBOUNDS    = UInt32(1) << 0
+const IR_FLAG_INBOUNDS    = one(UInt32) << 0
 # This statement is marked as @inline by user
-const IR_FLAG_INLINE      = UInt32(1) << 1
+const IR_FLAG_INLINE      = one(UInt32) << 1
 # This statement is marked as @noinline by user
-const IR_FLAG_NOINLINE    = UInt32(1) << 2
-const IR_FLAG_THROW_BLOCK = UInt32(1) << 3
+const IR_FLAG_NOINLINE    = one(UInt32) << 2
+const IR_FLAG_THROW_BLOCK = one(UInt32) << 3
 # This statement was proven :effect_free
-const IR_FLAG_EFFECT_FREE = UInt32(1) << 4
+const IR_FLAG_EFFECT_FREE = one(UInt32) << 4
 # This statement was proven not to throw
-const IR_FLAG_NOTHROW     = UInt32(1) << 5
+const IR_FLAG_NOTHROW     = one(UInt32) << 5
 # This is :consistent
-const IR_FLAG_CONSISTENT  = UInt32(1) << 6
+const IR_FLAG_CONSISTENT  = one(UInt32) << 6
 # An optimization pass has updated this statement in a way that may
 # have exposed information that inference did not see. Re-running
 # inference on this statement may be profitable.
-const IR_FLAG_REFINED     = UInt32(1) << 7
+const IR_FLAG_REFINED     = one(UInt32) << 7
 # This is :noub == ALWAYS_TRUE
-const IR_FLAG_NOUB        = UInt32(1) << 8
+const IR_FLAG_NOUB        = one(UInt32) << 8
 
 # TODO: Both of these should eventually go away once
 # This is :effect_free == EFFECT_FREE_IF_INACCESSIBLEMEMONLY
-const IR_FLAG_EFIIMO      = UInt32(1) << 9
+const IR_FLAG_EFIIMO      = one(UInt32) << 9
 # This is :inaccessiblememonly == INACCESSIBLEMEM_OR_ARGMEMONLY
-const IR_FLAG_INACCESSIBLE_OR_ARGMEM = UInt32(1) << 10
+const IR_FLAG_INACCESSIBLE_OR_ARGMEM = one(UInt32) << 10
 
 const IR_FLAGS_EFFECTS = IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW | IR_FLAG_CONSISTENT | IR_FLAG_NOUB
 
+has_flag(curr::UInt32, flag::UInt32) = (curr & flag) == flag
+
 const TOP_TUPLE = GlobalRef(Core, :tuple)
 
 # This corresponds to the type of `CodeInfo`'s `inlining_cost` field
@@ -218,9 +220,9 @@ end
 
 _topmod(sv::OptimizationState) = _topmod(sv.mod)
 
-is_stmt_inline(stmt_flag::UInt32)      = stmt_flag & IR_FLAG_INLINE      ≠ 0
-is_stmt_noinline(stmt_flag::UInt32)    = stmt_flag & IR_FLAG_NOINLINE    ≠ 0
-is_stmt_throw_block(stmt_flag::UInt32) = stmt_flag & IR_FLAG_THROW_BLOCK ≠ 0
+is_stmt_inline(stmt_flag::UInt32)      = has_flag(stmt_flag, IR_FLAG_INLINE)
+is_stmt_noinline(stmt_flag::UInt32)    = has_flag(stmt_flag, IR_FLAG_NOINLINE)
+is_stmt_throw_block(stmt_flag::UInt32) = has_flag(stmt_flag, IR_FLAG_THROW_BLOCK)
 
 function new_expr_effect_flags(𝕃ₒ::AbstractLattice, args::Vector{Any}, src::Union{IRCode,IncrementalCompact}, pattern_match=nothing)
     Targ = args[1]
@@ -468,7 +470,7 @@ end
 
 function any_stmt_may_throw(ir::IRCode, bb::Int)
     for stmt in ir.cfg.blocks[bb].stmts
-        if (ir[SSAValue(stmt)][:flag] & IR_FLAG_NOTHROW) != 0
+        if has_flag(ir[SSAValue(stmt)], IR_FLAG_NOTHROW)
             return true
         end
     end
@@ -702,7 +704,7 @@ function scan_non_dataflow_flags!(inst::Instruction, sv::PostOptAnalysisState)
             # ignore control flow node – they are not removable on their own and thus not
             # have `IR_FLAG_EFFECT_FREE` but still do not taint `:effect_free`-ness of
             # the whole method invocation
-            sv.all_effect_free &= !iszero(flag & IR_FLAG_EFFECT_FREE)
+            sv.all_effect_free &= has_flag(flag, IR_FLAG_EFFECT_FREE)
         end
     elseif sv.all_effect_free
         if (isexpr(stmt, :invoke) || isexpr(stmt, :new) ||
@@ -714,8 +716,8 @@ function scan_non_dataflow_flags!(inst::Instruction, sv::PostOptAnalysisState)
             sv.all_effect_free = false
         end
     end
-    sv.all_nothrow &= !iszero(flag & IR_FLAG_NOTHROW)
-    if iszero(flag & IR_FLAG_NOUB)
+    sv.all_nothrow &= has_flag(flag, IR_FLAG_NOTHROW)
+    if !has_flag(flag, IR_FLAG_NOUB)
         # Special case: `:boundscheck` into `getfield` or memory operations is `:noub_if_noinbounds`
         if is_conditional_noub(inst, sv)
             sv.any_conditional_ub = true
@@ -960,11 +962,11 @@ function convert_to_ircode(ci::CodeInfo, sv::OptimizationState)
                     ((block + 1) != destblock) && cfg_delete_edge!(sv.cfg, block, destblock)
                     expr = Expr(:call, Core.typeassert, expr.cond, Bool)
                 elseif i + 1 in sv.unreachable
-                    @assert (ci.ssaflags[i] & IR_FLAG_NOTHROW) != 0
+                    @assert has_flag(ci.ssaflags[i], IR_FLAG_NOTHROW)
                     cfg_delete_edge!(sv.cfg, block, block + 1)
                     expr = GotoNode(expr.dest)
                 elseif expr.dest in sv.unreachable
-                    @assert (ci.ssaflags[i] & IR_FLAG_NOTHROW) != 0
+                    @assert has_flag(ci.ssaflags[i], IR_FLAG_NOTHROW)
                     cfg_delete_edge!(sv.cfg, block, block_for_inst(sv.cfg, expr.dest))
                     expr = nothing
                 end

base/compiler/ssair/EscapeAnalysis/EscapeAnalysis.jl

@@ -25,9 +25,9 @@ using ._TOP_MOD:     # Base definitions
     unwrap_unionall, !, !=, !==, &, *, +, -, :, <, <<, =>, >, |, ∈, ∉, ∩, ∪, ≠, ≤, ≥, ⊆
 using Core.Compiler: # Core.Compiler specific definitions
     Bottom, IRCode, IR_FLAG_NOTHROW, InferenceResult, SimpleInferenceLattice,
-    argextype, check_effect_free!, fieldcount_noerror, hasintersect, intrinsic_nothrow,
-    is_meta_expr_head, isbitstype, isexpr, println, setfield!_nothrow, singleton_type,
-    try_compute_field, try_compute_fieldidx, widenconst, ⊑, AbstractLattice
+    argextype, check_effect_free!, fieldcount_noerror, hasintersect, has_flag,
+    intrinsic_nothrow, is_meta_expr_head, isbitstype, isexpr, println, setfield!_nothrow,
+    singleton_type, try_compute_field, try_compute_fieldidx, widenconst, ⊑, AbstractLattice
 
 include(x) = _TOP_MOD.include(@__MODULE__, x)
 if _TOP_MOD === Core.Compiler
@@ -975,7 +975,7 @@ end
     error("unexpected assignment found: inspect `Main.pc` and `Main.pc`")
 end
 
-is_nothrow(ir::IRCode, pc::Int) = ir[SSAValue(pc)][:flag] & IR_FLAG_NOTHROW ≠ 0
+is_nothrow(ir::IRCode, pc::Int) = has_flag(ir[SSAValue(pc)], IR_FLAG_NOTHROW)
 
 # NOTE if we don't maintain the alias set that is separated from the lattice state, we can do
 # something like below: it essentially incorporates forward escape propagation in our default

base/compiler/ssair/inlining.jl

@@ -399,7 +399,7 @@ function ir_inline_item!(compact::IncrementalCompact, idx::Int, argexprs::Vector
 
     ssa_substitute = ir_prepare_inlining!(InsertHere(compact), compact, item.ir, item.mi, inlined_at, argexprs)
 
-    boundscheck = iszero(compact.result[idx][:flag] & IR_FLAG_INBOUNDS) ? boundscheck : :off
+    boundscheck = has_flag(compact.result[idx], IR_FLAG_INBOUNDS) ? :off : boundscheck
 
     # If the iterator already moved on to the next basic block,
     # temporarily re-open in again.
@@ -1032,7 +1032,7 @@ function handle_single_case!(todo::Vector{Pair{Int,Any}},
             stmt.head = :invoke
             pushfirst!(stmt.args, case.invoke)
         end
-        ir[SSAValue(idx)][:flag] |= flags_for_effects(case.effects)
+        add_flag!(ir[SSAValue(idx)], flags_for_effects(case.effects))
     elseif case === nothing
         # Do, well, nothing
     else
@@ -1257,21 +1257,22 @@ function check_effect_free!(ir::IRCode, idx::Int, @nospecialize(stmt), @nospecia
 end
 function check_effect_free!(ir::IRCode, idx::Int, @nospecialize(stmt), @nospecialize(rt), 𝕃ₒ::AbstractLattice)
     (consistent, effect_free_and_nothrow, nothrow) = stmt_effect_flags(𝕃ₒ, stmt, rt, ir)
+    inst = ir.stmts[idx]
     if consistent
-        ir.stmts[idx][:flag] |= IR_FLAG_CONSISTENT
+        add_flag!(inst, IR_FLAG_CONSISTENT)
     end
     if effect_free_and_nothrow
-        ir.stmts[idx][:flag] |= IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW
+        add_flag!(inst, IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW)
     elseif nothrow
-        ir.stmts[idx][:flag] |= IR_FLAG_NOTHROW
+        add_flag!(inst, IR_FLAG_NOTHROW)
     end
     if !(isexpr(stmt, :call) || isexpr(stmt, :invoke))
         # There is a bit of a subtle point here, which is that some non-call
         # statements (e.g. PiNode) can be UB:, however, we consider it
         # illegal to introduce such statements that actually cause UB (for any
         # input). Ideally that'd be handled at insertion time (TODO), but for
         # the time being just do that here.
-        ir.stmts[idx][:flag] |= IR_FLAG_NOUB
+        add_flag!(inst, IR_FLAG_NOUB)
     end
     return effect_free_and_nothrow
 end
@@ -1583,7 +1584,7 @@ function handle_cases!(todo::Vector{Pair{Int,Any}}, ir::IRCode, idx::Int, stmt::
         end
         push!(todo, idx=>UnionSplit(fully_covered, atype, cases))
     else
-        ir[SSAValue(idx)][:flag] |= flags_for_effects(joint_effects)
+        add_flag!(ir[SSAValue(idx)], flags_for_effects(joint_effects))
     end
     return nothing
 end
@@ -1682,7 +1683,7 @@ function inline_const_if_inlineable!(inst::Instruction)
         inst[:stmt] = quoted(rt.val)
         return true
     end
-    inst[:flag] |= IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW
+    add_flag!(inst, IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW)
     return false
 end
 
@@ -1879,7 +1880,7 @@ function ssa_substitute_op!(insert_node!::Inserter, subst_inst::Instruction, @no
                 return quoted(val)
             else
                 flag = subst_inst[:flag]
-                maybe_undef = (flag & IR_FLAG_NOTHROW) == 0 && isa(val, TypeVar)
+                maybe_undef = !has_flag(flag, IR_FLAG_NOTHROW) && isa(val, TypeVar)
                 (ret, tcheck_not) = insert_spval!(insert_node!, ssa_substitute.spvals_ssa::SSAValue, spidx, maybe_undef)
                 if maybe_undef
                     insert_node!(

base/compiler/ssair/ir.jl

@@ -283,6 +283,10 @@ function setindex!(node::Instruction, newval::Instruction)
     return node
 end
 
+has_flag(inst::Instruction, flag::UInt32) = has_flag(inst[:flag], flag)
+add_flag!(inst::Instruction, flag::UInt32) = inst[:flag] |= flag
+sub_flag!(inst::Instruction, flag::UInt32) = inst[:flag] &= ~flag
+
 struct NewNodeInfo
     # Insertion position (interpretation depends on which array this is in)
     pos::Int
@@ -334,18 +338,24 @@ function NewInstruction(inst::Instruction;
     return NewInstruction(stmt, type, info, line, flag)
 end
 @specialize
-effect_free_and_nothrow(newinst::NewInstruction) = NewInstruction(newinst; flag=add_flag(newinst, IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW))
-with_flags(newinst::NewInstruction, flags::UInt32) = NewInstruction(newinst; flag=add_flag(newinst, flags))
-without_flags(newinst::NewInstruction, flags::UInt32) = NewInstruction(newinst; flag=sub_flag(newinst, flags))
+effect_free_and_nothrow(newinst::NewInstruction) = add_flag(newinst, IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW)
 function add_flag(newinst::NewInstruction, newflag::UInt32)
     flag = newinst.flag
-    flag === nothing && return newflag
-    return flag | newflag
+    if flag === nothing
+        flag = newflag
+    else
+        flag |= newflag
+    end
+    return NewInstruction(newinst; flag)
 end
 function sub_flag(newinst::NewInstruction, newflag::UInt32)
     flag = newinst.flag
-    flag === nothing && return IR_FLAG_NULL
-    return flag & ~newflag
+    if flag === nothing
+        flag = IR_FLAG_NULL
+    else
+        flag &= ~newflag
+    end
+    return NewInstruction(newinst; flag)
 end
 
 struct IRCode
@@ -1325,7 +1335,7 @@ function process_node!(compact::IncrementalCompact, result_idx::Int, inst::Instr
     elseif isa(stmt, GlobalRef)
         total_flags = IR_FLAG_CONSISTENT | IR_FLAG_EFFECT_FREE
         flag = result[result_idx][:flag]
-        if (flag & total_flags) == total_flags
+        if has_flag(flag, total_flags)
             ssa_rename[idx] = stmt
         else
             ssa_rename[idx] = SSAValue(result_idx)
@@ -1532,7 +1542,7 @@ function process_node!(compact::IncrementalCompact, result_idx::Int, inst::Instr
         else
             # Constant assign, replace uses of this ssa value with its result
         end
-        if (inst[:flag] & IR_FLAG_REFINED) != 0 && !isa(stmt, Refined)
+        if has_flag(inst, IR_FLAG_REFINED) && !isa(stmt, Refined)
             # If we're compacting away an instruction that was marked as refined,
             # leave a marker in the ssa_rename, so we can taint any users.
             stmt = Refined(stmt)
@@ -1767,7 +1777,7 @@ function maybe_erase_unused!(callback::Function, compact::IncrementalCompact, id
     stmt = inst[:stmt]
     stmt === nothing && return false
     inst[:type] === Bottom && return false
-    effect_free = (inst[:flag] & (IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW)) == IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW
+    effect_free = has_flag(inst, (IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW))
     effect_free || return false
     foreachssa(stmt) do val::SSAValue
         if compact.used_ssas[val.id] == 1

base/compiler/ssair/irinterp.jl

@@ -138,7 +138,7 @@ function reprocess_instruction!(interp::AbstractInterpreter, inst::Instruction,
             if bb === nothing
                 bb = block_for_inst(ir, idx)
             end
-            inst[:flag] |= IR_FLAG_NOTHROW
+            add_flag!(inst, IR_FLAG_NOTHROW)
             if condval
                 inst[:stmt] = nothing
                 inst[:type] = Any
@@ -156,14 +156,14 @@ function reprocess_instruction!(interp::AbstractInterpreter, inst::Instruction,
         head = stmt.head
         if head === :call || head === :foreigncall || head === :new || head === :splatnew || head === :static_parameter || head === :isdefined || head === :boundscheck
             (; rt, effects) = abstract_eval_statement_expr(interp, stmt, nothing, irsv)
-            inst[:flag] |= flags_for_effects(effects)
+            add_flag!(inst, flags_for_effects(effects))
         elseif head === :invoke
             rt, (nothrow, noub) = concrete_eval_invoke(interp, stmt, stmt.args[1]::MethodInstance, irsv)
             if nothrow
-                inst[:flag] |= IR_FLAG_NOTHROW
+                add_flag!(inst, IR_FLAG_NOTHROW)
             end
             if noub
-                inst[:flag] |= IR_FLAG_NOUB
+                add_flag!(inst, IR_FLAG_NOUB)
             end
         elseif head === :throw_undef_if_not
             condval = maybe_extract_const_bool(argextype(stmt.args[2], ir))
@@ -197,7 +197,7 @@ function reprocess_instruction!(interp::AbstractInterpreter, inst::Instruction,
     if rt !== nothing
         if isa(rt, Const)
             inst[:type] = rt
-            if is_inlineable_constant(rt.val) && (inst[:flag] & (IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW)) == IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW
+            if is_inlineable_constant(rt.val) && has_flag(inst, (IR_FLAG_EFFECT_FREE | IR_FLAG_NOTHROW))
                 inst[:stmt] = quoted(rt.val)
             end
             return true
@@ -299,9 +299,9 @@ function _ir_abstract_constant_propagation(interp::AbstractInterpreter, irsv::IR
         typ = inst[:type]
         flag = inst[:flag]
         any_refined = false
-        if (flag & IR_FLAG_REFINED) != 0
+        if has_flag(flag, IR_FLAG_REFINED)
             any_refined = true
-            inst[:flag] &= ~IR_FLAG_REFINED
+            sub_flag!(inst, IR_FLAG_REFINED)
         end
         for ur in userefs(stmt)
             val = ur[]
@@ -351,8 +351,8 @@ function _ir_abstract_constant_propagation(interp::AbstractInterpreter, irsv::IR
             irsv.curridx = idx
             stmt = inst[:stmt]
             flag = inst[:flag]
-            if (flag & IR_FLAG_REFINED) != 0
-                inst[:flag] &= ~IR_FLAG_REFINED
+            if has_flag(flag, IR_FLAG_REFINED)
+                sub_flag!(inst, IR_FLAG_REFINED)
                 push!(stmt_ip, idx)
             end
             check_ret!(stmt, idx)
@@ -408,8 +408,8 @@ function _ir_abstract_constant_propagation(interp::AbstractInterpreter, irsv::IR
     nothrow = noub = true
     for idx = 1:length(ir.stmts)
         flag = ir[SSAValue(idx)][:flag]
-        nothrow &= !iszero(flag & IR_FLAG_NOTHROW)
-        noub &= !iszero(flag & IR_FLAG_NOUB)
+        nothrow &= has_flag(flag, IR_FLAG_NOTHROW)
+        noub &= has_flag(flag, IR_FLAG_NOUB)
         (nothrow | noub) || break
     end