Move coverage effects analysis into inference

Code coverage is implemented as an optimization pass that inserts an SSA
IR node during optimization, however effects analysis is perfomed during
inference, and so the desired effects tainting that should occur from
insertion of the code coverage IR node is ignored.

This teaches `InferenceState` to taint itself with the effects flag
 `effects_free = ALWAYS_FALSE` when coverage is applicable to this
inference state's method.

base/compiler/inferencestate.jl

@@ -129,14 +129,15 @@ mutable struct InferenceState
  # Set by default for toplevel frame.
  restrict_abstract_call_sites::Bool
  cached::Bool # TODO move this to InferenceResult?
+ insert_coverage::Bool
 
  # The interpreter that created this inference state. Not looked at by
  # NativeInterpreter. But other interpreters may use this to detect cycles
  interp::AbstractInterpreter
 
  # src is assumed to be a newly-allocated CodeInfo, that can be modified in-place to contain intermediate results
  function InferenceState(result::InferenceResult, src::CodeInfo, cache::Symbol,
- interp::AbstractInterpreter)
+  interp::AbstractInterpreter)
  linfo = result.linfo
  world = get_world_counter(interp)
  def = linfo.def
@@ -179,6 +180,32 @@ mutable struct InferenceState
  bestguess = Bottom
  ipo_effects = EFFECTS_TOTAL
 
+ # check if coverage mode is enabled
+ insert_coverage = coverage_enabled(mod)
+ if !insert_coverage && JLOptions().code_coverage == 3 # path-specific coverage mode
+ linetable = src.linetable
+ if isa(linetable, Vector{Any})
+ for line in linetable
+ line = line::LineInfoNode
+ if is_file_tracked(line.file)
+ # if any line falls in a tracked file enable coverage for all
+ insert_coverage = true
+ break
+ end
+ end
+ elseif isa(linetable, Vector{LineInfo})
+ for line in linetable
+ if is_file_tracked(line.file)
+ insert_coverage = true
+ break
+ end
+ end
+ end
+ end
+ if insert_coverage
+ ipo_effects = Effects(ipo_effects; effect_free = ALWAYS_FALSE)
+ end
+
  params = InferenceParams(interp)
  restrict_abstract_call_sites = isa(linfo.def, Module)
  @assert cache === :no || cache === :local || cache === :global
@@ -189,7 +216,7 @@ mutable struct InferenceState
  currbb, currpc, ip, handler_at, ssavalue_uses, bb_vartables, ssavaluetypes, stmt_edges, stmt_info,
  pclimitations, limitations, cycle_backedges, callers_in_cycle, dont_work_on_me, parent, inferred,
  result, valid_worlds, bestguess, ipo_effects,
- params, restrict_abstract_call_sites, cached,
+ params, restrict_abstract_call_sites, cached, insert_coverage,
  interp)
 
  # some more setups

base/compiler/optimize.jl

@@ -149,13 +149,14 @@ mutable struct OptimizationState{Interp<:AbstractInterpreter}
  slottypes::Vector{Any}
  inlining::InliningState{Interp}
  cfg::Union{Nothing,CFG}
+ insert_coverage::Bool
 end
 function OptimizationState(frame::InferenceState, params::OptimizationParams,
  interp::AbstractInterpreter, recompute_cfg::Bool=true)
  inlining = InliningState(frame, params, interp)
  cfg = recompute_cfg ? nothing : frame.cfg
  return OptimizationState(frame.linfo, frame.src, nothing, frame.stmt_info, frame.mod,
- frame.sptypes, frame.slottypes, inlining, cfg)
+ frame.sptypes, frame.slottypes, inlining, cfg, frame.insert_coverage)
 end
 function OptimizationState(linfo::MethodInstance, src::CodeInfo, params::OptimizationParams,
  interp::AbstractInterpreter)
@@ -540,18 +541,6 @@ function convert_to_ircode(ci::CodeInfo, sv::OptimizationState)
  linetable = collect(LineInfoNode, linetable::Vector{Any})::Vector{LineInfoNode}
  end
 
- # check if coverage mode is enabled
- coverage = coverage_enabled(sv.mod)
- if !coverage && JLOptions().code_coverage == 3 # path-specific coverage mode
- for line in linetable
- if is_file_tracked(line.file)
- # if any line falls in a tracked file enable coverage for all
- coverage = true
- break
- end
- end
- end
-
  # Go through and add an unreachable node after every
  # Union{} call. Then reindex labels.
  code = copy_exprargs(ci.code)
@@ -567,7 +556,7 @@ function convert_to_ircode(ci::CodeInfo, sv::OptimizationState)
  prevloc = zero(eltype(ci.codelocs))
  while idx <= length(code)
  codeloc = codelocs[idx]
- if coverage && codeloc != prevloc && codeloc != 0
+ if sv.insert_coverage && codeloc != prevloc && codeloc != 0
  # insert a side-effect instruction before the current instruction in the same basic block
  insert!(code, idx, Expr(:code_coverage_effect))
  insert!(codelocs, idx, codeloc)
@@ -578,7 +567,7 @@ function convert_to_ircode(ci::CodeInfo, sv::OptimizationState)
  ssachangemap = fill(0, nstmts)
  end
  if labelchangemap === nothing
- labelchangemap = coverage ? fill(0, nstmts) : ssachangemap
+ labelchangemap = fill(0, nstmts)
  end
  ssachangemap[oldidx] += 1
  if oldidx < length(labelchangemap)
@@ -599,11 +588,11 @@ function convert_to_ircode(ci::CodeInfo, sv::OptimizationState)
  ssachangemap = fill(0, nstmts)
  end
  if labelchangemap === nothing
- labelchangemap = coverage ? fill(0, nstmts) : ssachangemap
+ labelchangemap = sv.insert_coverage ? fill(0, nstmts) : ssachangemap
  end
  if oldidx < length(ssachangemap)
  ssachangemap[oldidx + 1] += 1
- coverage && (labelchangemap[oldidx + 1] += 1)
+ sv.insert_coverage && (labelchangemap[oldidx + 1] += 1)
  end
  idx += 1
  end