From 6164aa6bcfc9a37cc8ebd31dbbe4e0654288785d Mon Sep 17 00:00:00 2001
From: Tim Holy <tim.holy@gmail.com>
Date: Wed, 27 Oct 2021 09:39:04 -0500
Subject: [PATCH] Add warntype_last (fixing inference probs.) (#175)

After left-clicking on a bar, you can call `warntype_last()`
from the REPL and see the results of `code_warntype`
for the bar you clicked on.
---
 Project.toml       |  2 ++
 README.md          | 23 +++++++++++++++++++++--
 src/ProfileView.jl | 13 ++++++++++++-
 test/runtests.jl   | 14 ++++++++++++++
 4 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/Project.toml b/Project.toml
index e809aea..8e607f1 100644
--- a/Project.toml
+++ b/Project.toml
@@ -13,6 +13,7 @@ Gtk = "4c0ca9eb-093a-5379-98c5-f87ac0bbbf44"
 GtkReactive = "27996c0f-39cd-5cc1-a27a-05f136f946b6"
 InteractiveUtils = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
 IntervalSets = "8197267c-284f-5f27-9208-e0e47529a953"
+MethodAnalysis = "85b6ec6f-f7df-4429-9514-a64bcd9ee824"
 Profile = "9abbd945-dff8-562f-b5e8-e1ebf5ef1b79"
 UUIDs = "cf7118a7-6976-5b1a-9a39-7adc72f591a4"
 
@@ -25,6 +26,7 @@ Graphics = "0.4, 1"
 Gtk = "0.18, 1"
 GtkReactive = "0.7, 1"
 IntervalSets = "0.2, 0.3, 0.4, 0.5"
+MethodAnalysis = "0.4"
 julia = "1"
 
 [extras]
diff --git a/README.md b/README.md
index 4f54a3b..5cc4341 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@
 
 # Introduction
 
-This package contains tools for visualizing profiling data collected
+This package contains tools for visualizing and interacting with profiling data collected
 with [Julia's][Julia] built-in sampling
 [profiler][Profiling]. It
 can be helpful for getting a big-picture overview of the major
@@ -19,6 +19,13 @@ This type of plot is known as a [flame
 graph](https://github.com/brendangregg/FlameGraph).
 The main logic is handled by the [FlameGraphs][FlameGraphs] package; this package is just a visualization front-end.
 
+Compared to other flamegraph viewers, ProfileView adds a number of additional useful interactivity features, such as:
+
+- left-clicking to take you to the source code for a particular statement
+- analyzing inference problems via `code_warntype` for calls that may be deep in your call chain.
+
+These features are described in detail below.
+
 ## Installation
 
 Within Julia, use the [package manager][pkg]:
@@ -27,7 +34,7 @@ using Pkg
 Pkg.add("ProfileView")
 ```
 
-## Usage and visual interpretation
+## Tutorial: usage and visual interpretation
 
 To demonstrate ProfileView, first we have to collect some profiling
 data. Here's a simple test function for demonstration:
@@ -111,6 +118,15 @@ from the absence of pastel-colored bars above much of the red, we
 might guess that this makes a substantial
 contribution to its total run time.
 
+To determine the nature of the inference problem(s) in a red bar, left-click on it
+and then enter
+
+```julia
+julia> warntype_last()
+```
+
+at the REPL. You'll see the result of Julia's `code_warntype` for that particular call.
+
 ## GUI features
 
 ### Gtk Interface
@@ -140,6 +156,9 @@ contribution to its total run time.
   window, which you can populate with saved data by clicking on the
   "open" icon.
 
+- After clicking on a bar, you can type `warntype_last` and see the
+  result of `code_warntype` for the call represented by that bar.
+
 **NOTE**: ProfileView does not support the old JLD-based `*.jlprof` files anymore.
 Use the format provided by FlameGraphs v0.2 and higher.
 
diff --git a/src/ProfileView.jl b/src/ProfileView.jl
index 66cfe04..497b979 100644
--- a/src/ProfileView.jl
+++ b/src/ProfileView.jl
@@ -7,6 +7,7 @@ end
 using Profile
 using FlameGraphs
 using Base.StackTraces: StackFrame
+using MethodAnalysis
 using InteractiveUtils
 using Gtk.ShortNames, GtkReactive, Colors, FileIO, IntervalSets
 import Cairo
@@ -15,10 +16,20 @@ using Graphics
 using FlameGraphs: Node, NodeData
 using Gtk.GConstants.GdkModifierType: SHIFT, CONTROL, MOD1
 
-export @profview
+export @profview, warntype_last
 
 const clicked = Ref{Any}(nothing)   # for getting access to the clicked bar
 
+"""
+    warntype_last()
+    warntype_last(io::IO; kwargs...)
+
+Show `code_warntype` for the most recently-clicked bar.
+
+Optionally direct output to stream `io`. Keyword arguments are passed to `code_warntype`.
+"""
+warntype_last(io::IO=stdout; kwargs...) = code_warntype(io, call_type(ProfileView.clicked[].linfo.specTypes)...; kwargs...)
+
 svgwrite(args...; kwargs...) = error("SVG support has moved to the ProfileSVG package")
 
 mutable struct ZoomCanvas
diff --git a/test/runtests.jl b/test/runtests.jl
index a7c81a7..d07363e 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -1,4 +1,5 @@
 using ProfileView
+using Test
 
 function profile_test(n)
     for i = 1:n
@@ -52,3 +53,16 @@ ProfileView.view(data, lidict=lidict)
 
 
 ProfileView.closeall()
+
+# Test `warntype_last`
+function add2(x)
+    y = x[1] + x[2]
+    return y, backtrace()
+end
+_, bt = add2(Any[1,2])
+st = stacktrace(bt)
+ProfileView.clicked[] = st[1]
+io = IOBuffer()
+warntype_last(io)
+str = String(take!(io))
+@test occursin("Base.getindex(x, 1)::ANY", str)