[VPlan] Script to extract VPlan digraphs from log

[rengolin]

Summary

The vectoriser's debug log prints VPlan digraphs, but it's a bit
cumbersome to extract them and render them into PNG images. This script
does exactly that, being careful enough to extract all individual plans,
name them appropriately and save in either .dot or .png files.

Usage:

$ $LLVM_SRC/utils/extract_vplan.py < debug.log 
Exporting VF1UF1 to DOT: VPlanVF1UF1.dot
Exporting VF24UF1 to DOT: VPlanVF24UF1.dot

$ $LLVM_SRC/utils/extract_vplan.py --png < debug.log 
Exporting VF1UF1 to PNG via dot: VPlanVF1UF1.png
Exporting VF24UF1 to PNG via dot: VPlanVF24UF1.png

[fhahn]

Great, I think we should definitely make it easier to visualize the vplans. I left a few python comments with suggestions, but they are mostly personal preference. I think in the future we may want something like a -dump-vplans flag, to conveniently dump plans as they are transformed.

utils/extract_vplan.py

25

My python regex knowledge is a bit rusty, but I think it might be possible to simplify this a bit by having a multi line regex, something like pattern = re.compile(r"(digraph VPlan {.*})",re.DOTALL)

I am curious now and will give that a try.

44

could this be something like for (name, plan) in zip(Names, VPlans):?

57

could be with open(filename, 'w') as out: out.write(VPlans[i])

[fhahn]

utils/extract_vplan.py

25

pattern = re.compile(r"(digraph VPlan {.*?\n})",re.DOTALL)

matches = re.findall(pattern, sys.stdin.read())

-> matches should be a list containing one string per digraph VPlan {}. I guess the regex could also be tweaked to extract the name, but that might make it a bit more complicated.

[rengolin]

Hi Florian,

Indeed, the "zip" and "with" Python idioms are much nicer, thanks!

I haven't used glob read because I wanted to make sure I got the VF/UF from the right line.

I have now made it even more explicitly by changing the search to a match and making sure the beginning or the line is the one I want.

cheers,
--renato

[rengolin]

Thanks Florian, your regex version is still easy to use and much cleaner.

Patch updated.

[rengolin]

I'm wondering... should we choose between dot and png? Or should we always print the dot file and, upon --png flag, also the png file?

[hsaito]

In D53142#1262181, @rengolin wrote:

I'm wondering... should we choose between dot and png? Or should we always print the dot file and, upon --png flag, also the png file?

I think either dot or png should be fine, and either can be default. If anyone need both, they can run the command twice.

[rengolin]

Consistent messages.

[rengolin]

(very gentle ping) :)

[fhahn]

LGTM, thanks!

utils/extract_vplan.py

35

nit: line quite long

utils/extract_vplan.py

+#!/usr/bin/env python
+
+# This script extracts the VPlan digraphs from the vectoriser debug messages
+# and saves them in individual dot files (one for each plan). Optionally, and
+# providing 'dot' is installed, it can also render the dot into a PNG file.
+
+import sys
+import re
+import argparse
+import shutil
+import subprocess
+
+parser = argparse.ArgumentParser()
+parser.add_argument('--png', action='store_true')
+args = parser.parse_args()
+
+dot = shutil.which('dot')
+if args.png and not dot:
+    raise RuntimeError("Can't export to PNG without 'dot' in the system")
+
+pattern = re.compile(r"(digraph VPlan {.*?\n})",re.DOTALL)
+matches = re.findall(pattern, sys.stdin.read())
+
+for vplan in matches:
+    m = re.search("graph \[.+(VF=.+,UF.+), ", vplan)
+    if not m:
+        raise ValueError("Can't get the right VPlan name")
+    name = re.sub('[^a-zA-Z0-9]', '', m.group(1))
+
+    if args.png:
+        filename = 'VPlan' + name + '.png'
+        print("Exporting " + name + " to PNG via dot: " + filename)
+        p = subprocess.Popen([dot, '-Tpng', '-o', filename], encoding='utf-8',
+                              stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        out, err = p.communicate(input=vplan)
+        if err:
+            raise RuntimeError("Error running dot: " + err)
+
+    else:
+        filename = 'VPlan' + name + '.dot'
+        print("No visualisation requested, saving to file: " + filename)
+        with open(filename, 'w') as out:
+            out.write(vplan)