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Merge 867fd7d into 7d7a456
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@JeffBezanson
JeffBezanson authored Nov 16, 2017
2 parents 7d7a456 + 867fd7d commit a3b9983
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Showing 14 changed files with 2,275 additions and 824 deletions.
113 changes: 84 additions & 29 deletions base/codevalidation.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -24,14 +24,16 @@ const VALID_EXPR_HEADS = ObjectIdDict(
:isdefined => 1:1,
:simdloop => 0:0,
:gc_preserve_begin => 0:typemax(Int),
:gc_preserve_end => 0:typemax(Int)
:gc_preserve_end => 0:typemax(Int),
:thunk => 1:1
)

# @enum isn't defined yet, otherwise I'd use it for this
const INVALID_EXPR_HEAD = "invalid expression head"
const INVALID_EXPR_NARGS = "invalid number of expression args"
const INVALID_LVALUE = "invalid LHS value"
const INVALID_RVALUE = "invalid RHS value"
const INVALID_RETURN = "invalid argument to :return"
const INVALID_CALL_ARG = "invalid :call argument"
const EMPTY_SLOTNAMES = "slotnames field is empty"
const SLOTFLAGS_MISMATCH = "length(slotnames) != length(slotflags)"
Expand All @@ -40,6 +42,7 @@ const SLOTTYPES_MISMATCH_UNINFERRED = "uninferred CodeInfo slottypes field is no
const SSAVALUETYPES_MISMATCH = "not all SSAValues in AST have a type in ssavaluetypes"
const SSAVALUETYPES_MISMATCH_UNINFERRED = "uninferred CodeInfo ssavaluetypes field does not equal the number of present SSAValues"
const NON_TOP_LEVEL_METHOD = "encountered `Expr` head `:method` in non-top-level code (i.e. `nargs` > 0)"
const NON_TOP_LEVEL_GLOBAL = "encountered `Expr` head `:global` in non-top-level code (i.e. `nargs` > 0)"
const SIGNATURE_NARGS_MISMATCH = "method signature does not match number of method arguments"
const SLOTNAMES_NARGS_MISMATCH = "CodeInfo for method contains fewer slotnames than the number of method arguments"

Expand All @@ -56,44 +59,78 @@ InvalidCodeError(kind::AbstractString) = InvalidCodeError(kind, nothing)
Validate `c`, logging any violation by pushing an `InvalidCodeError` into `errors`.
"""
function validate_code!(errors::Vector{>:InvalidCodeError}, c::CodeInfo, is_top_level::Bool = false)
function validate_val!(@nospecialize(x))
if isa(x, Expr)
if x.head == :call || x.head == :invoke
for arg in x.args
if !is_valid_argument(arg)
push!(errors, InvalidCodeError(INVALID_CALL_ARG, arg))
else
validate_val!(arg)
end
end
end
elseif isa(x, SSAValue)
id = x.id + 1 # ensures that id > 0 for use with BitSet
!in(id, ssavals) && push!(ssavals, id)
end
end

ssavals = BitSet()
lhs_slotnums = BitSet()
walkast(c.code) do x
for x in c.code
if isa(x, Expr)
!is_top_level && x.head == :method && push!(errors, InvalidCodeError(NON_TOP_LEVEL_METHOD))
if !is_top_level
x.head === :method && push!(errors, InvalidCodeError(NON_TOP_LEVEL_METHOD))
x.head === :global && push!(errors, InvalidCodeError(NON_TOP_LEVEL_GLOBAL))
end
narg_bounds = get(VALID_EXPR_HEADS, x.head, -1:-1)
nargs = length(x.args)
if narg_bounds == -1:-1
push!(errors, InvalidCodeError(INVALID_EXPR_HEAD, (x.head, x)))
elseif !in(nargs, narg_bounds)
push!(errors, InvalidCodeError(INVALID_EXPR_NARGS, (x.head, nargs, x)))
elseif x.head == :(=)
elseif x.head === :(=)
lhs, rhs = x.args
if !is_valid_lvalue(lhs)
push!(errors, InvalidCodeError(INVALID_LVALUE, lhs))
elseif isa(lhs, SlotNumber) && !in(lhs.id, lhs_slotnums)
n = lhs.id
push!(lhs_slotnums, n)
end
if !is_valid_rvalue(rhs)
if !is_valid_rvalue(lhs, rhs)
push!(errors, InvalidCodeError(INVALID_RVALUE, rhs))
end
elseif x.head == :call || x.head == :invoke
for arg in x.args
if !is_valid_rvalue(arg)
push!(errors, InvalidCodeError(INVALID_CALL_ARG, arg))
end
validate_val!(lhs)
validate_val!(rhs)
elseif x.head === :gotoifnot
if !is_valid_argument(x.args[1])
push!(errors, InvalidCodeError(INVALID_CALL_ARG, x.args[1]))
end
validate_val!(x.args[1])
elseif x.head === :return
if !is_valid_return(x.args[1])
push!(errors, InvalidCodeError(INVALID_RETURN, x.args[1]))
end
validate_val!(x.args[1])
else
validate_val!(x)
end
elseif isa(x, SSAValue)
id = x.id + 1 # ensures that id > 0 for use with BitSet
!in(id, ssavals) && push!(ssavals, id)
elseif isa(x, NewvarNode)
elseif isa(x, LabelNode)
elseif isa(x, GotoNode)
elseif x === nothing
elseif isa(x, SlotNumber)
elseif isa(x, GlobalRef)
elseif isa(x, LineNumberNode)
else
push!(errors, InvalidCodeError("invalid statement", x))
end
end
nslotnames = length(c.slotnames)
nslotflags = length(c.slotflags)
nssavals = length(ssavals)
nslotnames == 0 && push!(errors, InvalidCodeError(EMPTY_SLOTNAMES))
!is_top_level && nslotnames == 0 && push!(errors, InvalidCodeError(EMPTY_SLOTNAMES))
nslotnames != nslotflags && push!(errors, InvalidCodeError(SLOTFLAGS_MISMATCH, (nslotnames, nslotflags)))
if c.inferred
nslottypes = length(c.slottypes)
Expand All @@ -118,32 +155,50 @@ the `CodeInfo` instance associated with `mi`.
"""
function validate_code!(errors::Vector{>:InvalidCodeError}, mi::Core.MethodInstance,
c::Union{Void,CodeInfo} = Core.Inference.retrieve_code_info(mi))
m = mi.def::Method
n_sig_params = length(Core.Inference.unwrap_unionall(m.sig).parameters)
if (m.isva ? (n_sig_params < (m.nargs - 1)) : (n_sig_params != m.nargs))
push!(errors, InvalidCodeError(SIGNATURE_NARGS_MISMATCH, (m.isva, n_sig_params, m.nargs)))
is_top_level = mi.def isa Module
if is_top_level
mnargs = 0
else
m = mi.def::Method
mnargs = m.nargs
n_sig_params = length(Core.Inference.unwrap_unionall(m.sig).parameters)
if (m.isva ? (n_sig_params < (mnargs - 1)) : (n_sig_params != mnargs))
push!(errors, InvalidCodeError(SIGNATURE_NARGS_MISMATCH, (m.isva, n_sig_params, mnargs)))
end
end
if isa(c, CodeInfo)
m.nargs > length(c.slotnames) && push!(errors, InvalidCodeError(SLOTNAMES_NARGS_MISMATCH))
validate_code!(errors, c, m.nargs == 0)
mnargs > length(c.slotnames) && push!(errors, InvalidCodeError(SLOTNAMES_NARGS_MISMATCH))
validate_code!(errors, c, is_top_level)
end
return errors
end

validate_code(args...) = validate_code!(Vector{InvalidCodeError}(), args...)

function walkast(f, stmts::Array)
for stmt in stmts
f(stmt)
isa(stmt, Expr) && walkast(f, stmt.args)
is_valid_lvalue(x) = isa(x, Slot) || isa(x, SSAValue) || isa(x, GlobalRef)

function is_valid_argument(x)
if isa(x, Slot) || isa(x, SSAValue) || isa(x, GlobalRef) || isa(x, QuoteNode) ||
(isa(x,Expr) && (x.head in (:static_parameter, :boundscheck, :copyast))) ||
isa(x, Number) || isa(x, AbstractString) || isa(x, Char) || isa(x, Tuple) ||
isa(x, Type) || isa(x, Core.Box) || isa(x, Module) || x === nothing
return true
end
# TODO: consider being stricter about what needs to be wrapped with QuoteNode
return !(isa(x,Expr) || isa(x,Symbol) || isa(x,GotoNode) || isa(x,LabelNode) ||
isa(x,LineNumberNode) || isa(x,NewvarNode))
end

is_valid_lvalue(x) = isa(x, SlotNumber) || isa(x, SSAValue) || isa(x, GlobalRef)

function is_valid_rvalue(x)
isa(x, Expr) && return !in(x.head, (:gotoifnot, :line, :const, :meta))
return !isa(x, GotoNode) && !isa(x, LabelNode) && !isa(x, LineNumberNode)
function is_valid_rvalue(lhs, x)
is_valid_argument(x) && return true
if isa(x, Expr) && x.head in (:new, :the_exception, :isdefined, :call, :invoke, :foreigncall, :gc_preserve_begin)
return true
# TODO: disallow `globalref = call` when .typ field is removed
#return isa(lhs, SSAValue) || isa(lhs, Slot)
end
return false
end

is_valid_return(x) = is_valid_argument(x) || (isa(x,Expr) && x.head in (:new, :lambda))

is_flag_set(byte::UInt8, flag::UInt8) = (byte & flag) == flag
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