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Commit Graph

4 Commits

Author SHA1 Message Date
David Blaikie
dfadb4e9ee [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction
See r230786 and r230794 for similar changes to gep and load
respectively.

Call is a bit different because it often doesn't have a single explicit
type - usually the type is deduced from the arguments, and just the
return type is explicit. In those cases there's no need to change the
IR.

When that's not the case, the IR usually contains the pointer type of
the first operand - but since typed pointers are going away, that
representation is insufficient so I'm just stripping the "pointerness"
of the explicit type away.

This does make the IR a bit weird - it /sort of/ reads like the type of
the first operand: "call void () %x(" but %x is actually of type "void
()*" and will eventually be just of type "ptr". But this seems not too
bad and I don't think it would benefit from repeating the type
("void (), void () * %x(" and then eventually "void (), ptr %x(") as has
been done with gep and load.

This also has a side benefit: since the explicit type is no longer a
pointer, there's no ambiguity between an explicit type and a function
that returns a function pointer. Previously this case needed an explicit
type (eg: a function returning a void() function was written as
"call void () () * @x(" rather than "call void () * @x(" because of the
ambiguity between a function returning a pointer to a void() function
and a function returning void).

No ambiguity means even function pointer return types can just be
written alone, without writing the whole function's type.

This leaves /only/ the varargs case where the explicit type is required.

Given the special type syntax in call instructions, the regex-fu used
for migration was a bit more involved in its own unique way (as every
one of these is) so here it is. Use it in conjunction with the apply.sh
script and associated find/xargs commands I've provided in rr230786 to
migrate your out of tree tests. Do let me know if any of this doesn't
cover your cases & we can iterate on a more general script/regexes to
help others with out of tree tests.

About 9 test cases couldn't be automatically migrated - half of those
were functions returning function pointers, where I just had to manually
delete the function argument types now that we didn't need an explicit
function type there. The other half were typedefs of function types used
in calls - just had to manually drop the * from those.

import fileinput
import sys
import re

pat = re.compile(r'((?:=|:|^|\s)call\s(?:[^@]*?))(\s*$|\s*(?:(?:\[\[[a-zA-Z0-9_]+\]\]|[@%](?:(")?[\\\?@a-zA-Z0-9_.]*?(?(3)"|)|{{.*}}))(?:\(|$)|undef|inttoptr|bitcast|null|asm).*$)')
addrspace_end = re.compile(r"addrspace\(\d+\)\s*\*$")
func_end = re.compile("(?:void.*|\)\s*)\*$")

def conv(match, line):
  if not match or re.search(addrspace_end, match.group(1)) or not re.search(func_end, match.group(1)):
    return line
  return line[:match.start()] + match.group(1)[:match.group(1).rfind('*')].rstrip() + match.group(2) + line[match.end():]

for line in sys.stdin:
  sys.stdout.write(conv(re.search(pat, line), line))

llvm-svn: 235145
2015-04-16 23:24:18 +00:00
Philip Reames
7a73afff41 [RewriteStatepointsForGC] Use an actual liveness algorithm
When rewriting statepoints to make relocations explicit, we need to have a conservative but consistent notion of where a particular pointer is live at a particular site. The old code just used dominance, which is correct, but decidedly more conservative then it needed to be. This patch implements a simple dataflow algorithm that's run one per function (well, twice counting fixup after base pointer insertion). There's still lots of room to make this faster, but it's fast enough for all practical purposes today.

Differential Revision: http://reviews.llvm.org/D8674

llvm-svn: 234657
2015-04-10 22:53:14 +00:00
Philip Reames
7a2e8f33b1 [RewriteStatepointsForGC] Fix another order of iteration bug
It turns out the naming of inserted phis and selects is sensative to the order in which two sets are iterated.  We need to nail this down to avoid non-deterministic output and possible test failures.  

The modified test is the one I first noticed something odd in.  The change is making it more strict to report the error.  With the test change, but without the code change, the test fails roughly 1 in 5.  With the code change, I've run ~30 runs without error.

Long term, the right fix here is to adjust the naming scheme.  I'm checking in this hack to avoid any possible non-determinism in the tests over the weekend.  HJust because I only noticed one case doesn't mean it's actually the only case.  I hope to get to the right change Monday.

std->llvm data structure changes bugfix change #3

llvm-svn: 230835
2015-02-28 01:52:09 +00:00
Philip Reames
937676755d [RewriteStatepointsForGC] Add tests for the base pointer identification algorithm
These tests cover the 'base object' identification and rewritting portion of RewriteStatepointsForGC.  These aren't completely exhaustive, but they've proven to be reasonable effective over time at finding regressions.

In the process of porting these tests over, I found my first "cleanup per llvm code style standards" bug.  We were relying on the order of iteration when testing the base pointers found for a derived pointer.  When we switched from std::set to DenseSet, this stopped being a safe assumption.  I'm suspecting I'm going to find more of those.  In particular, I'm now really wondering about the main iteration loop for this algorithm.  I need to go take a closer look at the assumptions there.

I'm not really happy with the fact these are testing what is essentially debug output (i.e. enabled via command line flags).  Suggestions for how to structure this better are very welcome.  

llvm-svn: 230818
2015-02-28 00:20:48 +00:00