58 Commits

Author SHA1 Message Date
Duncan Sands
9c5a5b01b4 Load tracking means that the value analyzed may
not have pointer type.  In particular, it may
be the condition argument for a select or a GEP
index.  While I was unable to construct a testcase
for which some bits of the original pointer are
captured due to one of these, it's very very close
to being possible - so play safe and exclude these
possibilities.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61580 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-02 15:16:38 +00:00
Duncan Sands
338cd6ba6e When calculating 'nocapture' argument attributes, allow
the argument to be stored to an alloca by tracking uses
of the alloca.  This occurs 4 times (out of 7121, 0.05%)
in MultiSource/Applications, so may not be worth it.  On
the other hand, it is easy to do and fairly cheap.  The
functions it helps are: W_addcom and W_addlit in spiff;
process_args (argv) in d (make_dparser); ercPixConcealIMB
in JM/ldecod.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61570 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-02 11:54:37 +00:00
Duncan Sands
b2f2279056 Improve comments and reorganize a bit - no functionality
change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61569 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-02 11:46:24 +00:00
Nick Lewycky
6b05686283 Make adding nocapture a bit stronger. FreeInst is nocapture. Also,
functions that don't write can't leak a pointer except through 
the return value, so a void readonly function is implicitly nocapture.

Test these, and add a test that verifies that f1 calling f2 with an 
otherwise dead pointer gets both of them marked nocapture.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61552 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-02 03:46:56 +00:00
Duncan Sands
88e76757de Mention that this pass does escape analysis in the
leading comments.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61548 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-01 20:45:19 +00:00
Duncan Sands
1010941954 Look through phi nodes and select instructions when
calculating nocapture attributes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61535 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-31 20:21:34 +00:00
Duncan Sands
17da06ffbd Don't analyze arguments already marked 'nocapture'.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61532 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-31 18:08:59 +00:00
Duncan Sands
9e89ba31f1 Rename AddReadAttrs to FunctionAttrs, and teach it how
to work out (in a very simplistic way) which function
arguments (pointer arguments only) are only dereferenced
and so do not escape.  Mark such arguments 'nocapture'.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61525 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-31 16:14:43 +00:00