AbstractAnalyzer Framework

JETInterface

This baremodule exports names that form the APIs of AbstractAnalyzer Framework. using JET.JETInterface loads all names that are necessary to define a plugin analysis.

abstract type AbstractAnalyzer <: AbstractInterpreter end

An interface type of analyzers that are built on top of JET's analyzer framework.

When a new type NewAnalyzer implements the AbstractAnalyzer interface, it should be declared as subtype of AbstractAnalyzer, and is expected to the following interfaces:

1. AnalyzerState(analyzer::NewAnalyzer) -> AnalyzerState:
   Returns the AnalyzerState for analyzer::NewAnalyzer.

1. AbstractAnalyzer(analyzer::NewAnalyzer, state::AnalyzerState) -> NewAnalyzer:
   Constructs an new NewAnalyzer instance in the middle of JET's top-level analysis or abstract interpretation, given the previous analyzer::NewAnalyzer and state::AnalyzerState.

1. ReportPass(analyzer::NewAnalyzer) -> ReportPass:
   Returns ReportPass used for analyzer::NewAnalyzer.

1. AnalysisCache(analyzer::NewAnalyzer) -> analysis_cache::AnalysisCache:
   Returns code cache used for analyzer::NewAnalyzer.

See also AnalyzerState, ReportPass and AnalysisCache.

Example

JET.jl defines its default error analyzer JETAnalyzer <: AbstractAnalyzer as the following (modified a bit for the sake of simplicity):

# the default error analyzer for JET.jl
struct JETAnalyzer{RP<:ReportPass} <: AbstractAnalyzer
    state::AnalyzerState
    analysis_cache::AnalysisCache
    report_pass::RP
end

# AbstractAnalyzer API requirements
AnalyzerState(analyzer::JETAnalyzer) = analyzer.state
AbstractAnalyzer(analyzer::JETAnalyzer, state::AnalyzerState) = JETAnalyzer(ReportPass(analyzer), state)
ReportPass(analyzer::JETAnalyzer) = analyzer.report_pass
AnalysisCache(analyzer::JETAnalyzer) = analyzer.analysis_cache

mutable struct AnalyzerState
    ...
end

The mutable object that holds various states that are consumed by all AbstractAnalyzers.

AnalyzerState(analyzer::AbstractAnalyzer) -> AnalyzerState

If NewAnalyzer implements the AbstractAnalyzer interface, NewAnalyzer should implement this AnalyzerState(analyzer::NewAnalyzer) -> AnalyzerState interface.

A new AnalyzerState is supposed to be constructed using the general configurations passed as keyword arguments jetconfigs of the NewAnalyzer(; jetconfigs...) constructor, and the constructed AnalyzerState is usually kept within NewAnalyzer itself:

function NewAnalyzer(world::UInt=Base.get_world_counter(); jetconfigs...)
    ...
    state = AnalyzerState(world; jetconfigs...)
    return NewAnalyzer(..., state)
end
AnalyzerState(analyzer::NewAnalyzer) = analyzer.state

abstract type ReportPass end

An interface type that represents AbstractAnalyzer's report pass. analyzer::AbstractAnalyzer injects report passes using the (::ReportPass)(::Type{InferenceErrorReport}, ::AbstractAnalyzer, state, ...) interface, which provides a flexible and efficient layer to configure the analysis done by AbstractAnalyzer.

ReportPass(analyzer::AbstractAnalyzer) -> ReportPass

If NewAnalyzer implements the AbstractAnalyzer interface, NewAnalyzer should implement this ReportPass(analyzer::NewAnalyzer) -> ReportPass interface.

ReportPass allows NewAnalyzer to provide a very flexible configuration layer for NewAnalyzer's analysis; an user can define their own ReportPass to control how NewAnalyzer collects report errors while still using the analysis routine implemented by NewAnalyzer.

Example

For example, JETAnalyzer accepts a custom ReportPass passed as part of the general configurations (see the documentation of AbstractAnalyzer for an example implementation). And we can setup a custom report pass IgnoreAllExceptGlobalUndefVar, that ignores all the reports that are otherwise collected by JETAnalyzer except UndefVarErrorReport:

# custom report pass that ignores all the reports except `UndefVarErrorReport`
struct IgnoreAllExceptGlobalUndefVar <: ReportPass end

# ignores all the reports analyzed by `JETAnalyzer`
(::IgnoreAllExceptGlobalUndefVar)(::Type{<:InferenceErrorReport}, @nospecialize(_...)) = return

# forward to `BasicPass` to collect `UndefVarErrorReport`
function (::IgnoreAllExceptGlobalUndefVar)(::Type{UndefVarErrorReport}, @nospecialize(args...))
    BasicPass()(UndefVarErrorReport, args...)
end

no_method_error()    = 1 + "1"
undef_global_error() = undefvar
report_call(; report_pass=IgnoreAllExceptGlobalUndefVar()) do
    if rand(Bool)
        return no_method_error()    # "no matching method found" error report won't be reported here
    else
        return undef_global_error() # "`undefvar` is not defined" error report will be reported
    end
end

AnalysisCache(analyzer::AbstractAnalyzer) -> analysis_cache::AnalysisCache

Returns AnalysisCache for this analyzer::AbstractAnalyzer. AbstractAnalyzer instances can share the same cache if they perform the same analysis, otherwise their cache should be separated.

valid_configurations(analyzer::AbstractAnalyzer) -> names or nothing

Returns a set of names that are valid as a configuration for analyzer. names should be an iterator of Symbol. No validations are performed if nothing is returned.

aggregation_policy(analyzer::AbstractAnalyzer)

Defines how analyzer aggregates InferenceErrorReports. Defaults to default_aggregation_policy.

default_aggregation_policy(report::InferenceErrorReport) -> DefaultReportIdentity

Returns the default identity of report::InferenceErrorReport, where DefaultReportIdentity aggregates reports based on "error location" of each report. DefaultReportIdentity aggregates InferenceErrorReports aggressively in a sense that it ignores the identity of error point's MethodInstance, under the assumption that errors are identical as far as they're collected at the same file and line.

vscode_diagnostics_order(analyzer::AbstractAnalyzer) -> Bool

If true (default) a diagnostic will be reported at entry site. Otherwise it's reported at error point.

InferenceErrorReport

In order for Report <: InferenceErrorReport to implement the interface, it should satisfy the following requirements:

• Required fields
  Report should have the following fields, which explains where and how this error is reported:

  • vst::VirtualStackTrace: a virtual stack trace of the error
  • sig::Signature: a signature of the error point

  Note that Report can have additional fields other than vst and sig to explain why this error is reported (mostly used for print_report_message).

• Required overloads
  

  • copy_report(report::Report) -> new::Report
  • print_report_message(io::IO, report::Report)

• Optional overloads
  

  • print_signature(::Report) -> Bool
  • report_color(::Report) -> Symbol

Report <: InferenceErrorReport is supposed to be constructed using the following constructor

Report(::AbstractAnalyzer, state, spec_args...) -> Report

where state can be either of:

• state::Tuple{Union{Core.Compiler.InferenceState, Core.Compiler.OptimizationState}, Int64}: a state with the current program counter specified
• state::InferenceState: a state with the current program counter set to state.currpc
• state::InferenceResult: a state with the current program counter unknown
• state::MethodInstance: a state with the current program counter unknown

See also: @jetreport, VirtualStackTrace, VirtualFrame

copy_report(report::Report) where Report<:InferenceErrorReport -> new::Report

Returns new new::Report, that should be identical to the original report::Report, except that new.vst is copied from report.vst so that the further modification on report.vst that may happen in later abstract interpretation doesn't affect new.vst.

print_report_message(io::IO, report::Report) where Report<:InferenceErrorReport

Prints to io and describes why report is reported.

print_signature(::Report) where Report<:InferenceErrorReport -> Bool

Configures whether or not to print the report signature when printing Report (defaults to true).

report_color(::Report) where Report<:InferenceErrorReport -> Symbol

Configures the color for Report (defaults to :red).

analyze_and_report_call!(analyzer::AbstractAnalyzer, f, [types]; jetconfigs...) -> JETCallResult
analyze_and_report_call!(analyzer::AbstractAnalyzer, tt::Type{<:Tuple}; jetconfigs...) -> JETCallResult
analyze_and_report_call!(analyzer::AbstractAnalyzer, mi::MethodInstance; jetconfigs...) -> JETCallResult

A generic entry point to analyze a function call with AbstractAnalyzer. Finally returns the analysis result as JETCallResult. Note that this is intended to be used by developers of AbstractAnalyzer only. General users should use high-level entry points like report_call and report_opt.

call_test_ex(funcname::Symbol, testname::Symbol, ex0, __module__, __source__)

An internal utility function to implement a @test_call-like macro. See the implementation of @test_call.

func_test(func, testname::Symbol, args...; jetconfigs...)

An internal utility function to implement a test_call-like function. See the implementation of test_call.

analyze_and_report_file!(analyzer::AbstractAnalyzer, filename::AbstractString; jetconfigs...) -> JETToplevelResult

A generic entry point to analyze a file with AbstractAnalyzer. Finally returns the analysis result as JETToplevelResult. Note that this is intended to be used by developers of AbstractAnalyzer only. General users should use high-level entry points like report_file.

analyze_and_report_package!(analyzer::AbstractAnalyzer,
                            package::Union{AbstractString,Module,Nothing} = nothing;
                            jetconfigs...) -> JETToplevelResult

A generic entry point to analyze a package with AbstractAnalyzer. Finally returns the analysis result as JETToplevelResult. Note that this is intended to be used by developers of AbstractAnalyzer only. General users should use high-level entry points like report_package.

analyze_and_report_text!(analyzer::AbstractAnalyzer, text::AbstractString,
                         filename::AbstractString = "top-level";
                         jetconfigs...) -> JETToplevelResult

A generic entry point to analyze a top-level code with AbstractAnalyzer. Finally returns the analysis result as JETToplevelResult. Note that this is intended to be used by developers of AbstractAnalyzer only. General users should use high-level entry points like report_text.

add_new_report!(analyzer::AbstractAnalyzer, result::InferenceResult, report::InferenceErrorReport)

Adds new report::InferenceErrorReport associated with result::InferenceResult.

@jetreport struct NewReport <: InferenceErrorReport
    ...
end

A utility macro to define InferenceErrorReport. It can be very tedious to manually satisfy the InferenceErrorReport interfaces. JET internally uses this @jetreport utility macro, which takes a struct definition of InferenceErrorReport without the required fields specified, and automatically defines the struct as well as constructor definitions. If the report NewReport <: InferenceErrorReport is defined using @jetreport, then NewReport just needs to implement the print_report_message interface.

For example, JETAnalyzer's MethodErrorReport is defined as follows:

@jetreport struct MethodErrorReport <: InferenceErrorReport
    @nospecialize t # ::Union{Type, Vector{Type}}
    union_split::Int
end
function print_report_message(io::IO, (; t, union_split)::MethodErrorReport)
    print(io, "no matching method found for ")
    if union_split == 0
        print_callsig(io, t)
    else
        ts = t::Vector{Any}
        nts = length(ts)
        for i = 1:nts
            print_callsig(io, ts[i])
            i == nts || print(io, ", ")
        end
        print(io, " (", nts, '/', union_split, " union split)")
    end
end

and constructed as like MethodErrorReport(sv::InferenceState, atype::Any, 0).