1#!/usr/bin/env python3
2
3# Automatically formatted with yapf (https://github.com/google/yapf)
4
5# Script for automatic 'opt' pipeline reduction for when using the new
6# pass-manager (NPM). Based around the '-print-pipeline-passes' option.
7#
8# The reduction algorithm consists of several phases (steps).
9#
10# Step #0: Verify that input fails with the given pipeline and make note of the
11# error code.
12#
13# Step #1: Split pipeline in two starting from front and move forward as long as
14# first pipeline exits normally and the second pipeline fails with the expected
15# error code. Move on to step #2 with the IR from the split point and the
16# pipeline from the second invocation.
17#
18# Step #2: Remove passes from end of the pipeline as long as the pipeline fails
19# with the expected error code.
20#
21# Step #3: Make several sweeps over the remaining pipeline trying to remove one
22# pass at a time. Repeat sweeps until unable to remove any more passes.
23#
24# Usage example:
25# reduce_pipeline.py --opt-binary=./build-all-Debug/bin/opt --input=input.ll --output=output.ll --passes=PIPELINE [EXTRA-OPT-ARGS ...]
26
27import argparse
28import pipeline
29import shutil
30import subprocess
31import tempfile
32
33parser = argparse.ArgumentParser(
34    description=
35    'Automatic opt pipeline reducer. Unrecognized arguments are forwarded to opt.'
36)
37parser.add_argument('--opt-binary',
38                    action='store',
39                    dest='opt_binary',
40                    default='opt')
41parser.add_argument('--passes', action='store', dest='passes', required=True)
42parser.add_argument('--input', action='store', dest='input', required=True)
43parser.add_argument('--output', action='store', dest='output')
44parser.add_argument('--dont-expand-passes',
45                    action='store_true',
46                    dest='dont_expand_passes',
47                    help='Do not expand pipeline before starting reduction.')
48parser.add_argument(
49    '--dont-remove-empty-pm',
50    action='store_true',
51    dest='dont_remove_empty_pm',
52    help='Do not remove empty pass-managers from the pipeline during reduction.'
53)
54[args, extra_opt_args] = parser.parse_known_args()
55
56print('The following extra args will be passed to opt: {}'.format(
57    extra_opt_args))
58
59lst = pipeline.fromStr(args.passes)
60ll_input = args.input
61
62# Step #-1
63# Launch 'opt' once with '-print-pipeline-passes' to expand pipeline before
64# starting reduction. Allows specifying a default pipelines (e.g.
65# '-passes=default<O3>').
66if not args.dont_expand_passes:
67    run_args = [
68        args.opt_binary, '-disable-symbolication', '-disable-output',
69        '-print-pipeline-passes', '-passes={}'.format(pipeline.toStr(lst)),
70        ll_input
71    ]
72    run_args.extend(extra_opt_args)
73    opt = subprocess.run(run_args,
74                         stdout=subprocess.PIPE,
75                         stderr=subprocess.PIPE)
76    if opt.returncode != 0:
77        print('Failed to expand passes. Aborting.')
78        print(run_args)
79        print('exitcode: {}'.format(opt.returncode))
80        print(opt.stderr.decode())
81        exit(1)
82    stdout = opt.stdout.decode()
83    stdout = stdout[:stdout.rfind('\n')]
84    lst = pipeline.fromStr(stdout)
85    print('Expanded pass sequence: {}'.format(pipeline.toStr(lst)))
86
87# Step #0
88# Confirm that the given input, passes and options result in failure.
89print('---Starting step #0---')
90run_args = [
91    args.opt_binary, '-disable-symbolication', '-disable-output',
92    '-passes={}'.format(pipeline.toStr(lst)), ll_input
93]
94run_args.extend(extra_opt_args)
95opt = subprocess.run(run_args, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
96if opt.returncode >= 0:
97    print('Input does not result in failure as expected. Aborting.')
98    print(run_args)
99    print('exitcode: {}'.format(opt.returncode))
100    print(opt.stderr.decode())
101    exit(1)
102
103expected_error_returncode = opt.returncode
104print('-passes="{}"'.format(pipeline.toStr(lst)))
105
106# Step #1
107# Try to narrow down the failing pass sequence by splitting the pipeline in two
108# opt invocations (A and B) starting with invocation A only running the first
109# pipeline pass and invocation B the remaining. Keep moving the split point
110# forward as long as invocation A exits normally and invocation B fails with
111# the expected error. This will accomplish two things first the input IR will be
112# further reduced and second, with that IR, the reduced pipeline for invocation
113# B will be sufficient to reproduce.
114print('---Starting step #1---')
115prevLstB = None
116prevIntermediate = None
117tmpd = tempfile.TemporaryDirectory()
118
119for idx in range(pipeline.count(lst)):
120    [lstA, lstB] = pipeline.split(lst, idx)
121    if not args.dont_remove_empty_pm:
122        lstA = pipeline.prune(lstA)
123        lstB = pipeline.prune(lstB)
124
125    intermediate = 'intermediate-0.ll' if idx % 2 else 'intermediate-1.ll'
126    intermediate = tmpd.name + '/' + intermediate
127    run_args = [
128        args.opt_binary, '-disable-symbolication', '-S', '-o', intermediate,
129        '-passes={}'.format(pipeline.toStr(lstA)), ll_input
130    ]
131    run_args.extend(extra_opt_args)
132    optA = subprocess.run(run_args,
133                          stdout=subprocess.PIPE,
134                          stderr=subprocess.PIPE)
135    run_args = [
136        args.opt_binary, '-disable-symbolication', '-disable-output',
137        '-passes={}'.format(pipeline.toStr(lstB)), intermediate
138    ]
139    run_args.extend(extra_opt_args)
140    optB = subprocess.run(run_args,
141                          stdout=subprocess.PIPE,
142                          stderr=subprocess.PIPE)
143    if not (optA.returncode == 0
144            and optB.returncode == expected_error_returncode):
145        break
146    prevLstB = lstB
147    prevIntermediate = intermediate
148if prevLstB:
149    lst = prevLstB
150    ll_input = prevIntermediate
151print('-passes="{}"'.format(pipeline.toStr(lst)))
152
153# Step #2
154# Try removing passes from the end of the remaining pipeline while still
155# reproducing the error.
156print('---Starting step #2---')
157prevLstA = None
158for idx in reversed(range(pipeline.count(lst))):
159    [lstA, lstB] = pipeline.split(lst, idx)
160    if not args.dont_remove_empty_pm:
161        lstA = pipeline.prune(lstA)
162    run_args = [
163        args.opt_binary, '-disable-symbolication', '-disable-output',
164        '-passes={}'.format(pipeline.toStr(lstA)), ll_input
165    ]
166    run_args.extend(extra_opt_args)
167    optA = subprocess.run(run_args,
168                          stdout=subprocess.PIPE,
169                          stderr=subprocess.PIPE)
170    if optA.returncode != expected_error_returncode:
171        break
172    prevLstA = lstA
173if prevLstA:
174    lst = prevLstA
175print('-passes="{}"'.format(pipeline.toStr(lst)))
176
177# Step #3
178# Now that we have a pipeline that is reduced both front and back we do
179# exhaustive sweeps over the remainder trying to remove one pass at a time.
180# Repeat as long as reduction is possible.
181print('---Starting step #3---')
182while True:
183    keepGoing = False
184    for idx in range(pipeline.count(lst)):
185        candLst = pipeline.remove(lst, idx)
186        if not args.dont_remove_empty_pm:
187            candLst = pipeline.prune(candLst)
188        run_args = [
189            args.opt_binary, '-disable-symbolication', '-disable-output',
190            '-passes={}'.format(pipeline.toStr(candLst)), ll_input
191        ]
192        run_args.extend(extra_opt_args)
193        opt = subprocess.run(run_args,
194                             stdout=subprocess.PIPE,
195                             stderr=subprocess.PIPE)
196        if opt.returncode == expected_error_returncode:
197            lst = candLst
198            keepGoing = True
199    if not keepGoing:
200        break
201print('-passes="{}"'.format(pipeline.toStr(lst)))
202
203print('---FINISHED---')
204if args.output:
205    shutil.copy(ll_input, args.output)
206    print('Wrote output to \'{}\'.'.format(args.output))
207print('-passes="{}"'.format(pipeline.toStr(lst)))
208exit(0)
209