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#!/usr/bin/env python
'''
LLVM doesn't appear to have a way to remove unused functions. This little
script will do that. It requires annotations to be in the .ll file it parses
(run llvm-dis with -show-annotations).
Closure compiler can remove unused functions, however it is much faster
to remove them before Emscripten runs.
'''
import os, sys, re
def path_from_root(*pathelems):
rootpath = os.path.abspath(os.path.dirname(os.path.dirname(__file__)))
return os.path.join(rootpath, *pathelems)
exec(open(path_from_root('tools', 'shared.py'), 'r').read())
infile = sys.argv[1]
outfile = sys.argv[2]
lines = open(infile, 'r').read().split('\n')
class Dummy: pass
# Discover functions
functions = {}
func_header = re.compile('^define[^@]* (?P<ident>@\w+)\(.* {$')
func_footer = '}'
func_annot = re.compile('^; \[#uses=(?P<uses>\d+)\]$')
print '\nDiscovery pass 1\n'
for i in range(len(lines)):
line = lines[i]
m_header = func_header.match(line)
if m_header:
m_annot = func_annot.match(lines[i-1])
assert m_annot
ident = m_header.group('ident')
func = functions[ident] = Dummy()
func.uses = int(m_annot.group('uses')) # XXX This info from LLVM is very inaccurate
func.callers = set()
func.callees = set()
for ident in functions.iterkeys():
func = functions[ident]
#print ident
if '@main' not in functions:
print 'No @main found, not running DFE'
import shutil
shutil.copy(infile, outfile)
sys.exit(1)
print '\nDiscovery pass 2\n'
ident_frag = re.compile('[, ](?P<ident>@\w+)[, ()}\]]')
metadata = re.compile('!(?P<index>\d+) = metadata !{.*')
inside = None
for i in range(len(lines)):
line = lines[i]
if line == func_footer:
inside = None
continue
m_header = func_header.match(line)
if m_header:
inside = m_header.group('ident')
continue
meta = metadata.match(line)
for m in re.finditer(ident_frag, line):
ident = m.groups('ident')[0]
if ident not in functions: continue
if inside != ident:
functions[ident].callers.add(inside if inside else ('GLOBAL' if not meta else 'METADATA_'+str(i)+'_'+meta.groups('index')[0]))
if inside:
functions[inside].callees.add(ident)
functions['@main'].callers.add('GLOBAL')
for ident in functions.iterkeys():
func = functions[ident]
#print ident, func.uses, func.callers#, 'WARNING!' if func.uses != len(func.callers) else ''
# Garbage collect
print '\nGC pass 1\n'
for ident in functions.iterkeys():
func = functions[ident]
func.root = func.marked = False
for caller in func.callers:
if caller == 'GLOBAL':
func.root = True
#print 'ROOT:', ident
break
def mark_and_recurse(func):
if func.marked: return
func.marked = True
for callee in func.callees:
if callee == 'GLOBAL': continue
mark_and_recurse(functions[callee])
for ident in functions.iterkeys():
func = functions[ident]
if func.root:
mark_and_recurse(func)
marked = unmarked = 0
for ident in functions.iterkeys():
func = functions[ident]
if func.root: assert func.marked
#print ident, func.marked
marked += func.marked
unmarked += 1-func.marked
dead_metadatas = set() # metadata pruning pass
for ident in functions.iterkeys():
func = functions[ident]
if func.marked: continue
for caller in func.callers:
if caller.startswith('METADATA_'):
dummy, i, index = caller.split('_')
lines[int(i)] = ';'
dead_metadatas.add(int(index))
inner_metadata = re.compile('metadata !(?P<index>\d+)')
for i in range(len(lines)):
line = lines[i]
if metadata.match(line):
lines[i] = re.sub(inner_metadata, lambda m: 'i32 0' if int(m.groups('index')[0]) in dead_metadatas else m.string[m.start():m.end()], line)
print 'Marked: ', marked, ', unmarked: ', unmarked
# Write
print '\nWriting\n'
inside = None
marked = False
target = open(outfile, 'w')
for line in lines:
if line == func_footer:
inside = None
if marked: target.write(line + '\n')
continue
m_header = func_header.match(line)
if m_header:
inside = m_header.group('ident')
marked = functions[inside].marked
######### if metadata.match(line): continue # metadata is not enough to keep things alive
if line.startswith('!llvm.dbg.sp = '): continue
if not inside or marked:
if len(line) > 0:
target.write(line + '\n')
target.close()
|
