stacktraces.jl
# This file is a part of Julia. License is MIT: http://julialang.org/license
module StackTraces
import Base: hash, ==, show
import Base.Serializer: serialize, deserialize
export StackTrace, StackFrame, stacktrace, catch_stacktrace
"""
StackFrame
Stack information representing execution context, with the following fields:
- `func::Symbol`
The name of the function containing the execution context.
- `linfo::Nullable{Core.MethodInstance}`
The MethodInstance containing the execution context (if it could be found).
- `file::Symbol`
The path to the file containing the execution context.
- `line::Int`
The line number in the file containing the execution context.
- `from_c::Bool`
True if the code is from C.
- `inlined::Bool`
True if the code is from an inlined frame.
- `pointer::Int64`
Representation of the pointer to the execution context as returned by `backtrace`.
"""
immutable StackFrame # this type should be kept platform-agnostic so that profiles can be dumped on one machine and read on another
"the name of the function containing the execution context"
func::Symbol
"the path to the file containing the execution context"
file::Symbol
"the line number in the file containing the execution context"
line::Int
"the MethodInstance containing the execution context (if it could be found)"
linfo::Nullable{Core.MethodInstance}
"true if the code is from C"
from_c::Bool
"true if the code is from an inlined frame"
inlined::Bool
"representation of the pointer to the execution context as returned by `backtrace`"
pointer::UInt64 # Large enough to be read losslessly on 32- and 64-bit machines.
end
StackFrame(func, file, line) = StackFrame(func, file, line, Nullable{Core.MethodInstance}(), false, false, 0)
"""
StackTrace
An alias for `Vector{StackFrame}` provided for convenience; returned by calls to
`stacktrace` and `catch_stacktrace`.
"""
typealias StackTrace Vector{StackFrame}
const empty_sym = Symbol("")
const UNKNOWN = StackFrame(empty_sym, empty_sym, -1, Nullable{Core.MethodInstance}(), true, false, 0) # === lookup(C_NULL)
#=
If the StackFrame has function and line information, we consider two of them the same if
they share the same function/line information.
=#
function ==(a::StackFrame, b::StackFrame)
a.line == b.line && a.from_c == b.from_c && a.func == b.func && a.file == b.file && a.inlined == b.inlined
end
function hash(frame::StackFrame, h::UInt)
h += 0xf4fbda67fe20ce88 % UInt
h = hash(frame.line, h)
h = hash(frame.file, h)
h = hash(frame.func, h)
h = hash(frame.from_c, h)
h = hash(frame.inlined, h)
end
# provide a custom serializer that skips attempting to serialize the `outer_linfo`
# which is likely to contain complex references, types, and module references
# that may not exist on the receiver end
function serialize(s::AbstractSerializer, frame::StackFrame)
Serializer.serialize_type(s, typeof(frame))
serialize(s, frame.func)
serialize(s, frame.file)
write(s.io, frame.line)
write(s.io, frame.from_c)
write(s.io, frame.inlined)
write(s.io, frame.pointer)
end
function deserialize(s::AbstractSerializer, ::Type{StackFrame})
func = deserialize(s)
file = deserialize(s)
line = read(s.io, Int)
from_c = read(s.io, Bool)
inlined = read(s.io, Bool)
pointer = read(s.io, UInt64)
return StackFrame(func, file, line, Nullable{Core.MethodInstance}(), from_c, inlined, pointer)
end
"""
lookup(pointer::Union{Ptr{Void}, UInt}) -> Vector{StackFrame}
Given a pointer to an execution context (usually generated by a call to `backtrace`), looks
up stack frame context information. Returns an array of frame information for all functions
inlined at that point, innermost function first.
"""
function lookup(pointer::Ptr{Void})
infos = ccall(:jl_lookup_code_address, Any, (Ptr{Void}, Cint), pointer - 1, false)
isempty(infos) && return [StackFrame(empty_sym, empty_sym, -1, Nullable{Core.MethodInstance}(), true, false, convert(UInt64, pointer))]
res = Array{StackFrame}(length(infos))
for i in 1:length(infos)
info = infos[i]
@assert(length(info) == 7)
li = info[4] === nothing ? Nullable{Core.MethodInstance}() : Nullable{Core.MethodInstance}(info[4])
res[i] = StackFrame(info[1], info[2], info[3], li, info[5], info[6], info[7])
end
return res
end
lookup(pointer::UInt) = lookup(convert(Ptr{Void}, pointer))
"""
stacktrace([trace::Vector{Ptr{Void}},] [c_funcs::Bool=false]) -> StackTrace
Returns a stack trace in the form of a vector of `StackFrame`s. (By default stacktrace
doesn't return C functions, but this can be enabled.) When called without specifying a
trace, `stacktrace` first calls `backtrace`.
"""
function stacktrace(trace::Vector{Ptr{Void}}, c_funcs::Bool=false)
stack = vcat(map(lookup, trace)...)::StackTrace
# Remove frames that come from C calls.
if !c_funcs
filter!(frame -> !frame.from_c, stack)
end
# Remove frame for this function (and any functions called by this function).
remove_frames!(stack, :stacktrace)
end
stacktrace(c_funcs::Bool=false) = stacktrace(backtrace(), c_funcs)
"""
catch_stacktrace([c_funcs::Bool=false]) -> StackTrace
Returns the stack trace for the most recent error thrown, rather than the current execution
context.
"""
catch_stacktrace(c_funcs::Bool=false) = stacktrace(catch_backtrace(), c_funcs)
"""
remove_frames!(stack::StackTrace, name::Symbol)
Takes a `StackTrace` (a vector of `StackFrames`) and a function name (a `Symbol`) and
removes the `StackFrame` specified by the function name from the `StackTrace` (also removing
all frames above the specified function). Primarily used to remove `StackTraces` functions
from the `StackTrace` prior to returning it.
"""
function remove_frames!(stack::StackTrace, name::Symbol)
splice!(stack, 1:findlast(frame -> frame.func == name, stack))
return stack
end
function remove_frames!(stack::StackTrace, names::Vector{Symbol})
splice!(stack, 1:findlast(frame -> frame.func in names, stack))
return stack
end
function show_spec_linfo(io::IO, frame::StackFrame)
if isnull(frame.linfo)
if frame.func === empty_sym
@printf(io, "ip:%#x", frame.pointer)
else
print(io, frame.func)
end
else
linfo = get(frame.linfo)
if isdefined(linfo, :def)
Base.show_lambda_types(io, linfo)
else
Base.show(io, linfo)
end
end
end
function show(io::IO, frame::StackFrame; full_path::Bool=false)
print(io, " in ")
show_spec_linfo(io, frame)
if frame.file !== empty_sym
file_info = full_path ? string(frame.file) : basename(string(frame.file))
print(io, " at ", file_info, ":")
if frame.line >= 0
print(io, frame.line)
else
print(io, "?")
end
end
if frame.inlined
print(io, " [inlined]")
end
end
end