overridden symbols. OK'ed off-line by Doug. 
// rdar://12378793

llvm-svn: 165807

Patch from Daniel Malea that cleans up the process parameters for Process/Thread classes for POSIX and Linux.

llvm-svn: 165806

ConstString Host::GetVendorString();
ConstString Host::GetOSString();

comes from. It now all comes from the Host::GetArchitecture (eSystemDefaultArchitecture) like the Apple build was doing to minimize the number of places that need to be updated when Host::GetArchitecture () is called.

llvm-svn: 165805

Modified patch from Matt Kopec that makes sure the run lock is acquired when attaching and makes sure the pid is being set on linux in the process info.

llvm-svn: 165804

llvm/test/CodeGen/PowerPC/2012-10-12-bitcast.ll: Try to fix failure on non-ppc hosts, to add -mattr=+altivec.

llvm-svn: 165803

On PowerPC, a bitcast of <16 x i8> to i128 may run through a code
path in ExpandRes_BITCAST that attempts to do an intermediate
bitcast to a <4 x i32> vector, and then construct the Hi and Lo parts
of the resulting i128 by pairing up two of those i32 vector elements
each.  The code already recognizes that on a big-endian system, the
first two vector elements form the Hi part, and the final two vector
elements form the Lo part (vice-versa from the little-endian situation).

However, we also need to take endianness into account when forming each
of those separate pairs:  on a big-endian system, vector element 0 is
the *high* part of the pair making up the Hi part of the result, and
vector element 1 is the low part of the pair.  The code currently always
uses vector element 0 as the low part and vector element 1 as the high
part, as is appropriate for little-endian platforms only.

This patch fixes this by swapping the vector elements as they are
paired up as appropriate.

llvm-svn: 165802

llvm-svn: 165797

llvm-svn: 165796

llvm-svn: 165795

llvm-svn: 165794

llvm-svn: 165793

llvm-svn: 165792

Patch by Amara Emerson.

llvm-svn: 165791

llvm-svn: 165790

llvm-svn: 165789

llvm-svn: 165788

-Wnon-virtual-dtor for real.

llvm-svn: 165787

virtual destructors.

llvm-svn: 165786

llvm-svn: 165785

DependenceAnalysis.cpp:1164:32: warning: implicit truncation from 'int' to bitfield changes value from -5 to 3
      [-Wconstant-conversion]
    Result.DV[Level].Direction &= ~Dependence::DVEntry::GT;
                               ^  ~~~~~~~~~~~~~~~~~~~~~~~~

Patch from Preston Briggs <preston.briggs@gmail.com>.

llvm-svn: 165784

llvm-svn: 165783

llvm-svn: 165782

llvm-svn: 165781

llvm-svn: 165780

llvm-svn: 165779

not legal. However, it should use a div instruction + mul + sub if divide is
legal. The rem legalization code was missing a check and incorrectly uses a
divrem libcall even when div is legal.

rdar://12481395

llvm-svn: 165778

llvm-svn: 165777

llvm-svn: 165776

The intent of this document is to be the go-to document for anybody who
wants to write new documentation, but isn't familiar with Sphinx.

llvm-svn: 165775

Conditionally use an integral cast for BodyFarm support for OSAtomicCompareAndSwap if the return type is not a boolean.

llvm-svn: 165774

#undef only occurs if that submodule is imported.

llvm-svn: 165773

llvm-svn: 165772

has none of its own. Factor in Doug's comments.
// rdar://12378793

llvm-svn: 165771

Updates to llvm/Support/Casting.h have rendered these classof()'s
irrelevant.

llvm-svn: 165770

Somewhat troublingly, without this implemented, the check inside
isa_impl<> would silently use the parent's `classof()` when determining
whether it was okay to downcast from the parent to the child!

Bug analysis:

A build failure after removing the parent's `classof()` initially
alerted me to the bug, after which a little bit of thinking and reading
of the code identified the root cause.

The compiler could be made to prevent this bug from happening if there
were a way to ensure that in the code

    template <typename To, typename From, typename Enabler = void>
    struct isa_impl {
      static inline bool doit(const From &Val) {
        return To::classof(&Val);
      }
    };

that `To::classof` is actually inside the class `To`, and not in a base
class. I am not aware of a way to check this in C++. If there is a means
to perform that check, please bring it up on the list and this will be
fixed.

There is a high likelihood that there are other instances of this same
bug in the codebase.

llvm-svn: 165769

* Fix confusing explanation regarding abstract classes.

* Clarify auto-upcasting and why `Shape` doesn't need a `classof()`.

* Add section `Rules of Thumb` with some quick summary tips.

llvm-svn: 165768

isa<> et al. automatically infer when the cast is an upcast (including a
self-cast), so these are no longer necessary.

llvm-svn: 165767

Recent changes to isa<>/dyn_cast<> have made unnecessary those classof()
of the form:

    static bool classof(const Foo *) { return true; }

Accordingly, remove mention of such classof() from the documentation.

llvm-svn: 165766

Additionally, all such cases are handled with no dynamic check.

All `classof()` of the form

    class Foo {
      [...]
      static bool classof(const Bar *) { return true; }
      [...]
    }

where Foo is an ancestor of Bar are no longer necessary.
Don't write them!

Note: The exact test is `is_base_of<Foo, Bar>`, which is non-strict, so
that Foo is considered an ancestor of itself.

This leads to the following rule of thumb for LLVM-style RTTI:

    The argument type of `classof()` should be a strict ancestor.

For more information about implementing LLVM-style RTTI, see
docs/HowToSetUpLLVMStyleRTTI.rst

llvm-svn: 165765

This classof() is effectively saying that a MachineCodeEmitter "is-a"
JITEmitter, but JITEmitter is in fact a descendant of
MachineCodeEmitter, so this is not semantically correct. Consequently,
none of the assertions that rely on these classof() actualy check
anything.

Remove the RTTI (which didn't actually check anything) and use
static_cast<> instead.

Post-Mortem Bug Analysis
========================

Cause of the bug
----------------

r55022 appears to be the source of the classof() and assertions removed
by this commit. It aimed at removing some dynamic_cast<> that were
solely in the assertions. A typical diff hunk from that commit looked
like:

  -  assert(dynamic_cast<JITEmitter*>(MCE) && "Unexpected MCE?");
  -  JITEmitter *JE = static_cast<JITEmitter*>(getCodeEmitter());
  +  assert(isa<JITEmitter>(MCE) && "Unexpected MCE?");
  +  JITEmitter *JE = cast<JITEmitter>(getCodeEmitter());

Hence, the source of the bug then seems to be an attempt to replace
dynamic_cast<> with LLVM-style RTTI without properly setting up the
class hierarchy for LLVM-style RTTI. The bug therefore appears to be
simply a "thinko".

What initially indicated the presence of the bug
------------------------------------------------

After implementing automatic upcasting for isa<>, classof() functions of
the form

  static bool classof(const Foo *) { return true; }

were removed, since they only serve the purpose of optimizing
statically-OK upcasts. A subsequent recompilation triggered a build
failure on the isa<> tests within the removed asserts, since the
automatic upcasting (correctly) failed to substitute this classof().

Key to pinning down the root cause of the bug
---------------------------------------------

After being alerted to the presence of the bug, some thought about the
semantics which were being asserted by the buggy classof() revealed that
it was incorrect.

How the bug could have been prevented
-------------------------------------

This bug could have been prevented by better documentation for how to
set up LLVM-style RTTI. This should be solved by the recently added
documentation HowToSetUpLLVMStyleRTTI. However, this bug suggests that
the documentation should clearly explain the contract that classof()
must fulfill. The HowToSetUpLLVMStyleRTTI already explains this
contract, but it is a little tucked away. A future patch will expand
that explanation and make it more prominent.

There does not appear to be a simple way to have the compiler prevent
this bug, since fundamentally it boiled down to a spurious classof()
where the programmer made an erroneous statement about the conversion.
This suggests that perhaps the interface to LLVM-style RTTI of classof()
is not the best. There is already some evidence for this, since in a
number of places Clang has classof() forward to classofKind(Kind K)
which evaluates the cast in terms of just the Kind. This could probably
be generalized to simply a `static const Kind MyKind;` field in leaf
classes and `static const Kind firstMyKind, lastMyKind;` for non-leaf
classes, and have the rest of the work be done inside Casting.h,
assuming that the Kind enum is laid out in a preorder traversal of the
inheritance tree.

llvm-svn: 165764