Overlay of Core.throw_inexacterror results in bad codegen of kwarg call #48097
Labels
compiler:codegen
Generation of LLVM IR and native code
gpu
Affects running Julia on a GPU
regression
Regression in behavior compared to a previous version
Comments
maleadt
added
regression
Bisecting around on release-1.8, it looks like the backport of #44224 (5f0d551) did introduce this bug on there too, however the backport of #44515 (e1e02f6) fixed it again. The same applies to |
|
I guess another factor is #47157. The PR changes the internal representation of a call to kwfunc significantly, and indeed, it looks like this issue stems from
julia> @code_typed interp=GPUInterpreter() parent()
CodeInfo(
1 ─ return nothing
) => Nothing
julia> @code_typed interp=GPUInterpreter() parent()
CodeInfo(
1 ─ %1 = invoke Base._tuple_unique_fieldtypes(Tuple{Float32, Float64}::Any)::Core.SimpleVector
│ %2 = Core._apply_iterate(Base.iterate, Base.afoldl, (Base.var"#51#52"(),), %1)::Any
│ Core.apply_type(Base.Pairs, Symbol, %2, Tuple{Symbol, Symbol}, NamedTuple{(:a, :b), Tuple{Float32, Float64}})::Type{Base.Pairs{Symbol, _A, Tuple{Symbol, Symbol}, NamedTuple{(:a, :b), Tuple{Float32, Float64}}}} where _A
└── return nothing
) => Nothing |
|
That |
julia> (Base.infer_effects(; interp=GPUInterpreter()) do
Base._tuple_unique_fieldtypes(Tuple{Float32,Float64})
end).nonoverlayed
falseprobably because of dynamic dispatches. |
|
I tried to improve the effects with the following diff, but it looks like diff --git a/base/essentials.jl b/base/essentials.jl
index 2093c792dd..61e9b1b258 100644
--- a/base/essentials.jl
+++ b/base/essentials.jl
@@ -386,8 +386,10 @@ function isvatuple(@nospecialize(t))
return false
end
-unwrapva(t::Core.TypeofVararg) = isdefined(t, :T) ? t.T : Any
-unwrapva(@nospecialize(t)) = t
+function unwrapva(@nospecialize(t))
+ isa(t, Core.TypeofVararg) || return t
+ return isdefined(t, :T) ? t.T : Any
+end
function unconstrain_vararg_length(va::Core.TypeofVararg)
# construct a new Vararg type where its length is unconstrained,
diff --git a/base/tuple.jl b/base/tuple.jl
index d59c923921..c1d96fd2ca 100644
--- a/base/tuple.jl
+++ b/base/tuple.jl
@@ -208,15 +208,15 @@ eltype(t::Type{<:Tuple}) = _compute_eltype(t)
function _tuple_unique_fieldtypes(@nospecialize t)
@_total_meta
types = IdSet()
- t´ = unwrap_unionall(t)
# Given t = Tuple{Vararg{S}} where S<:Real, the various
# unwrapping/wrapping/va-handling here will return Real
if t isa Union
- union!(types, _tuple_unique_fieldtypes(rewrap_unionall(t´.a, t)))
- union!(types, _tuple_unique_fieldtypes(rewrap_unionall(t´.b, t)))
+ union!(types, _tuple_unique_fieldtypes(rewrap_unionall(t.a, t)))
+ union!(types, _tuple_unique_fieldtypes(rewrap_unionall(t.b, t)))
else
r = Union{}
- for ti in (t´::DataType).parameters
+ t´ = unwrap_unionall(t)::DataType
+ for ti in t´.parameters
r = push!(types, rewrap_unionall(unwrapva(ti), t))
end
end |
|
@maleadt Is it okay to call the original non-overlayed version of If we're fine with seeing the overlayed behavior of # Essentially, we want to see the overlayed behavior of these functions at actual runtime only,
# and we're fine with seeing their original non-overlayed behavior during compilation when they
# are concrete-evaluated.
const RUNTIME_ONLY_OVERLAYS = Any[
Base._tuple_unique_fieldtypes # necessary for accurate keyword func handling
]
function Core.Compiler.abstract_call_known(interp::GPUInterpreter, @nospecialize(f),
arginfo::Core.Compiler.ArgInfo, si::Core.Compiler.StmtInfo, sv::Core.Compiler.InferenceState,
max_methods::Int)
ret = @invoke Core.Compiler.abstract_call_known(interp::Core.Compiler.AbstractInterpreter, f::Any,
arginfo::Core.Compiler.ArgInfo, si::Core.Compiler.StmtInfo, sv::Core.Compiler.InferenceState,
max_methods::Int)
if f in RUNTIME_ONLY_OVERLAYS
new_effects = Core.Compiler.Effects(ret.effects; nonoverlayed=true)
ret = Core.Compiler.CallMeta(ret.rt, new_effects, ret.info)
end
return ret
end |
|
Well, upon a further thought, how does GPUCompiler call overlayed |
GPUCompiler.jl uses |
|
This has surfaced again, ref JuliaGPU/GPUCompiler.jl#399 Updated MWE: # pieces lifted from GPUCompiler.jl
using LLVM
# helper type to deal with the transition from Context to ThreadSafeContext
export JuliaContext
if VERSION >= v"1.9.0-DEV.516"
const JuliaContextType = ThreadSafeContext
else
const JuliaContextType = Context
end
function JuliaContext()
if VERSION >= v"1.9.0-DEV.115"
JuliaContextType()
else
isboxed_ref = Ref{Bool}()
typ = LLVMType(ccall(:jl_type_to_llvm, LLVM.API.LLVMTypeRef,
(Any, Ptr{Bool}), Any, isboxed_ref))
context(typ)
end
end
function JuliaContext(f)
if VERSION >= v"1.9.0-DEV.115"
JuliaContextType(f)
else
f(JuliaContext())
end
end
if VERSION >= v"1.9.0-DEV.516"
unwrap_context(ctx::ThreadSafeContext) = context(ctx)
end
unwrap_context(ctx::Context) = ctx
# CI cache
using Core.Compiler: CodeInstance, MethodInstance, InferenceParams, OptimizationParams
struct CodeCache
dict::IdDict{MethodInstance,Vector{CodeInstance}}
CodeCache() = new(Dict{MethodInstance,Vector{CodeInstance}}())
end
function Core.Compiler.setindex!(cache::CodeCache, ci::CodeInstance, mi::MethodInstance)
cis = get!(cache.dict, mi, CodeInstance[])
push!(cis, ci)
end
const GLOBAL_CI_CACHE = CodeCache()
using Core.Compiler: WorldView
function Core.Compiler.haskey(wvc::WorldView{CodeCache}, mi::MethodInstance)
Core.Compiler.get(wvc, mi, nothing) !== nothing
end
function Core.Compiler.get(wvc::WorldView{CodeCache}, mi::MethodInstance, default)
for ci in get!(wvc.cache.dict, mi, CodeInstance[])
if ci.min_world <= wvc.worlds.min_world && wvc.worlds.max_world <= ci.max_world
src = if ci.inferred isa Vector{UInt8}
ccall(:jl_uncompress_ir, Any, (Any, Ptr{Cvoid}, Any),
mi.def, C_NULL, ci.inferred)
else
ci.inferred
end
return ci
end
end
return default
end
function Core.Compiler.getindex(wvc::WorldView{CodeCache}, mi::MethodInstance)
r = Core.Compiler.get(wvc, mi, nothing)
r === nothing && throw(KeyError(mi))
return r::CodeInstance
end
function Core.Compiler.setindex!(wvc::WorldView{CodeCache}, ci::CodeInstance, mi::MethodInstance)
src = if ci.inferred isa Vector{UInt8}
ccall(:jl_uncompress_ir, Any, (Any, Ptr{Cvoid}, Any),
mi.def, C_NULL, ci.inferred)
else
ci.inferred
end
Core.Compiler.setindex!(wvc.cache, ci, mi)
end
function ci_cache_populate(interp, mi, min_world, max_world)
src = Core.Compiler.typeinf_ext_toplevel(interp, mi)
wvc = WorldView(GLOBAL_CI_CACHE, min_world, max_world)
@assert Core.Compiler.haskey(wvc, mi)
ci = Core.Compiler.getindex(wvc, mi)
if ci !== nothing && ci.inferred === nothing
@static if VERSION >= v"1.9.0-DEV.1115"
@atomic ci.inferred = src
else
ci.inferred = src
end
end
return ci
end
function ci_cache_lookup(mi, min_world, max_world)
wvc = WorldView(GLOBAL_CI_CACHE, min_world, max_world)
ci = Core.Compiler.get(wvc, mi, nothing)
if ci !== nothing && ci.inferred === nothing
return nothing
end
return ci
end
# interpreter
using Core.Compiler: AbstractInterpreter, InferenceResult, InferenceParams, InferenceState, OptimizationParams
struct GPUInterpreter <: AbstractInterpreter
local_cache::Vector{InferenceResult}
GPUInterpreter() = new(Vector{InferenceResult}())
end
Core.Compiler.InferenceParams(interp::GPUInterpreter) = InferenceParams()
Core.Compiler.OptimizationParams(interp::GPUInterpreter) = OptimizationParams()
Core.Compiler.get_world_counter(interp::GPUInterpreter) = Base.get_world_counter()
Core.Compiler.get_inference_cache(interp::GPUInterpreter) = interp.local_cache
Core.Compiler.code_cache(interp::GPUInterpreter) = WorldView(GLOBAL_CI_CACHE, Base.get_world_counter())
using Base.Experimental: @overlay, @MethodTable
@MethodTable(GLOBAL_METHOD_TABLE)
using Core.Compiler: OverlayMethodTable
if v"1.8-beta2" <= VERSION < v"1.9-" || VERSION >= v"1.9.0-DEV.120"
Core.Compiler.method_table(interp::GPUInterpreter) =
OverlayMethodTable(Base.get_world_counter(), GLOBAL_METHOD_TABLE)
else
Core.Compiler.method_table(interp::GPUInterpreter, sv::InferenceState) =
OverlayMethodTable(Base.get_world_counter(), GLOBAL_METHOD_TABLE)
end
# disable ir interpretation due to issues with overlay tables
@static if VERSION >= v"1.9.0-DEV.1248"
function Core.Compiler.concrete_eval_eligible(interp::GPUInterpreter,
@nospecialize(f), result::Core.Compiler.MethodCallResult, arginfo::Core.Compiler.ArgInfo)
ret = @invoke Core.Compiler.concrete_eval_eligible(interp::AbstractInterpreter,
f::Any, result::Core.Compiler.MethodCallResult, arginfo::Core.Compiler.ArgInfo)
ret === false && return nothing
return ret
end
end
function codegen(sig)
mi, _ = emit_julia(sig)
JuliaContext() do ctx
ir, _ = emit_llvm(mi; ctx)
strip_debuginfo!(ir)
string(ir)
end
end
function emit_julia(sig)
meth = which(sig)
(ti, env) = ccall(:jl_type_intersection_with_env, Any,
(Any, Any), sig, meth.sig)::Core.SimpleVector
meth = Base.func_for_method_checked(meth, ti, env)
method_instance = ccall(:jl_specializations_get_linfo, Ref{Core.MethodInstance},
(Any, Any, Any, UInt), meth, ti, env, Base.get_world_counter())
return method_instance, ()
end
function emit_llvm(@nospecialize(method_instance); ctx::JuliaContextType)
InitializeAllTargets()
InitializeAllTargetInfos()
InitializeAllAsmPrinters()
InitializeAllAsmParsers()
InitializeAllTargetMCs()
ir, compiled = irgen(method_instance; ctx)
entry_fn = compiled[method_instance].specfunc
entry = functions(ir)[entry_fn]
return ir, (; entry, compiled)
end
function irgen(method_instance::Core.MethodInstance;
ctx::JuliaContextType)
mod, compiled = compile_method_instance(method_instance; ctx)
entry_fn = compiled[method_instance].specfunc
entry = functions(mod)[entry_fn]
return mod, compiled
end
const _method_instances = Ref{Any}()
function _lookup_fun(mi, min_world, max_world)
push!(_method_instances[], mi)
ci_cache_lookup(mi, min_world, max_world)
end
function compile_method_instance(method_instance::MethodInstance; ctx::JuliaContextType)
world = Base.get_world_counter()
interp = GPUInterpreter()
if ci_cache_lookup(method_instance, world, typemax(Cint)) === nothing
ci_cache_populate(interp, method_instance, world, typemax(Cint))
end
method_instances = []
_method_instances[] = method_instances
lookup_cb = @cfunction(_lookup_fun, Any, (Any, UInt, UInt))
params = Base.CodegenParams(; lookup = Base.unsafe_convert(Ptr{Nothing}, lookup_cb))
GC.@preserve lookup_cb begin
native_code = if VERSION >= v"1.9.0-DEV.516"
mod = LLVM.Module("start"; ctx=unwrap_context(ctx))
ts_mod = ThreadSafeModule(mod; ctx)
if VERSION >= v"1.9.0-beta4.23"
ccall(:jl_create_native, Ptr{Cvoid},
(Vector{MethodInstance}, LLVM.API.LLVMOrcThreadSafeModuleRef, Ptr{Base.CodegenParams},
Cint, Cint, Cint, Csize_t),
[method_instance], ts_mod, Ref(params),
#=extern policy=# 1, #=imaging mode=# 0, #=external linkage=# 0,
Base.get_world_counter())
else
ccall(:jl_create_native, Ptr{Cvoid},
(Vector{MethodInstance}, LLVM.API.LLVMOrcThreadSafeModuleRef, Ptr{Base.CodegenParams}, Cint),
[method_instance], ts_mod, Ref(params), #=extern policy=# 1)
end
elseif VERSION >= v"1.9.0-DEV.115"
ccall(:jl_create_native, Ptr{Cvoid},
(Vector{MethodInstance}, LLVM.API.LLVMContextRef, Ptr{Base.CodegenParams}, Cint),
[method_instance], ctx, Ref(params), 1)
elseif VERSION >= v"1.8.0-DEV.661"
@assert ctx == JuliaContext()
ccall(:jl_create_native, Ptr{Cvoid},
(Vector{MethodInstance}, Ptr{Base.CodegenParams}, Cint),
[method_instance], Ref(params), 1)
else
@assert ctx == JuliaContext()
ccall(:jl_create_native, Ptr{Cvoid},
(Vector{MethodInstance}, Base.CodegenParams, Cint),
[method_instance], params, 1)
end
@assert native_code != C_NULL
llvm_mod_ref = if VERSION >= v"1.9.0-DEV.516"
ccall(:jl_get_llvm_module, LLVM.API.LLVMOrcThreadSafeModuleRef,
(Ptr{Cvoid},), native_code)
else
ccall(:jl_get_llvm_module, LLVM.API.LLVMModuleRef,
(Ptr{Cvoid},), native_code)
end
@assert llvm_mod_ref != C_NULL
if VERSION >= v"1.9.0-DEV.516"
llvm_ts_mod = LLVM.ThreadSafeModule(llvm_mod_ref)
llvm_mod = nothing
llvm_ts_mod() do mod
llvm_mod = mod
end
else
llvm_mod = LLVM.Module(llvm_mod_ref)
end
end
compiled = Dict()
for mi in method_instances
ci = ci_cache_lookup(mi, world, typemax(Cint))
if ci !== nothing
llvm_func_idx = Ref{Int32}(-1)
llvm_specfunc_idx = Ref{Int32}(-1)
ccall(:jl_get_function_id, Nothing,
(Ptr{Cvoid}, Any, Ptr{Int32}, Ptr{Int32}),
native_code, ci, llvm_func_idx, llvm_specfunc_idx)
llvm_func = if llvm_func_idx[] != -1
llvm_func_ref = ccall(:jl_get_llvm_function, LLVM.API.LLVMValueRef,
(Ptr{Cvoid}, UInt32), native_code, llvm_func_idx[]-1)
@assert llvm_func_ref != C_NULL
LLVM.name(LLVM.Function(llvm_func_ref))
else
nothing
end
llvm_specfunc = if llvm_specfunc_idx[] != -1
llvm_specfunc_ref = ccall(:jl_get_llvm_function, LLVM.API.LLVMValueRef,
(Ptr{Cvoid}, UInt32), native_code, llvm_specfunc_idx[]-1)
@assert llvm_specfunc_ref != C_NULL
LLVM.name(LLVM.Function(llvm_specfunc_ref))
else
nothing
end
compiled[mi] = (; ci, func=llvm_func, specfunc=llvm_specfunc)
end
end
return llvm_mod, compiled
end
############################################################################################
# compiler invocation
child(; kwargs...) = return
function parent()
child(; a=1f0, b=1.0)
return
end
# this override introduces a `jl_invoke`
@overlay GLOBAL_METHOD_TABLE @noinline Core.throw_inexacterror(f::Symbol, ::Type{T}, val) where {T} =
return
println(codegen(Tuple{typeof(parent)}))Bisected to #48838; @aviatesk is taking a look. In the mean time, #48838 has been reverted on the backports branch. |
aviatesk
added a commit
that referenced
this issue
Apr 26, 2023
When we skip inference of a call on `throw` block, previously we only checked if the call is overlayed or not. But the call may call an overlayed method internally, thus we need to conservatively taint the `:nonoverlayed` bit when `interp` uses overlay method table. Nevertheless this will not introduce any regressions on GPUCompiler stack (like #48097), since it defines `InferenceParams(::GPUInterpreter)` overload to turn off `unoptimize_throw_blocks` <https://github.com/JuliaGPU/GPUCompiler.jl/blob/d5086fb3d93bbc4795a96f6f1457898af46a24cb/src/interface.jl#L272>
aviatesk
added a commit
that referenced
this issue
Apr 27, 2023
…ll (#49518) When we skip inference of a call on `throw` block, previously we only checked if the call is overlayed or not. But the call may call an overlayed method internally, thus we need to conservatively taint the `:nonoverlayed` bit when `interp` uses overlay method table. Nevertheless this will not introduce any regressions on GPUCompiler stack (like #48097), since it defines `InferenceParams(::GPUInterpreter)` overload to turn off `unoptimize_throw_blocks` <https://github.com/JuliaGPU/GPUCompiler.jl/blob/d5086fb3d93bbc4795a96f6f1457898af46a24cb/src/interface.jl#L272>
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Backstory: CUDA.jl and other GPU back-ends use method overlays to replace GPU-incompatible functionality, like several exception-throwing functions. While we generally do support exception, replacing them at the LLVM level with custom reporting function, some are inherently GPU-incompatible due to string interpolation or untyped fields (resulting in a GC frame we cannot support). One such example is InexactError (from
boot.jl):To support this, we rewrite
throw_inexacterror:This used to work fine, but with specific kernels (that contain a kwarg function call where the kwargs are heterogeneously typed) we now get LLVM IR that performs dynamic function calls:
I bisected this to #44224, which is a bit weird, since that PR was back-ported to 1.8 too. It's possible that there's some interplay with other functionality only on 1.9, but that's unlikely as the PR was merged very shortly after 1.9 branched.
Anyway, the full MWE (reduced from GPUCompiler.jl):
cc @aviatesk, you previously looked at GPU-related overlay issues
Putting this on the milestone as this breaks parts of CUDA.jl, but again, I'm also happy to adapt CUDA.jl (although dropping the overlay of
throw_inexacterrorwill result in other code breaking, so that's not a great solution either).The text was updated successfully, but these errors were encountered: