Commit Graph

681 Commits

Author SHA1 Message Date
Zachary Turner
91e18f7639 Revert "Replace Execution Engine's mutex with std::recursive_mutex."
This reverts commit 1f502bd9d7, due to
GCC / MinGW's lack of support for C++11 threading.

It's possible this will go back in after we come up with a
reasonable solution.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211401 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-20 21:07:14 +00:00
Zachary Turner
1f502bd9d7 Replace Execution Engine's mutex with std::recursive_mutex.
This change has a bit of a trickle down effect due to the fact that
there are a number of derived implementations of ExecutionEngine,
and that the mutex is not tightly encapsulated so is used by other
classes directly.

Reviewed by: rnk

Differential Revision: http://reviews.llvm.org/D4196

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211214 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-18 20:17:35 +00:00
Zachary Turner
97a66e6049 Remove more occurrences of the unused-mutex-parameter pattern.
This pattern loses some of its usefulness when the mutex type is
statically polymorphic as opposed to runtime polymorphic, as
swapping out the mutex type requires changing a significant number
of function parameters, and templatizing the function parameter
requires the methods to be defined in the headers.

Furthermore, if LLVM is compiled with threads disabled then there
may even be no mutex to acquire anyway, so it should not be up to
individual APIs to know whether or not acquiring a mutex is required
to use those APIs to begin with.  It should be up to the user of the
API.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211125 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-17 21:54:18 +00:00
Zachary Turner
298ff80849 Cleanup more unreferenced MutexGuard parameters on functions.
These parameters are intended to serve as sort of a contract that
you cannot access the functions outside of a mutex.  However, the
entire JIT class cannot be accessed outside of a mutex anyway, and
all methods acquire a lock as soon as they are entered.  Since the
containing class already is not intended to be thread-safe, it only
serves to add code clutter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211071 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-16 22:41:08 +00:00
Rafael Espindola
cfee6c49ea Add a Constant version of stripPointerCasts.
Thanks to rnk for the suggestion.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210205 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-04 19:01:48 +00:00
Rafael Espindola
2d21b25393 Allow alias to point to an arbitrary ConstantExpr.
This  patch changes GlobalAlias to point to an arbitrary ConstantExpr and it is
up to MC (or the system assembler) to decide if that expression is valid or not.

This reduces our ability to diagnose invalid uses and how early we can spot
them, but it also lets us do things like

@test5 = alias inttoptr(i32 sub (i32 ptrtoint (i32* @test2 to i32),
                                 i32 ptrtoint (i32* @bar to i32)) to i32*)

An important implication of this patch is that the notion of aliased global
doesn't exist any more. The alias has to encode the information needed to
access it in its metadata (linkage, visibility, type, etc).

Another consequence to notice is that getSection has to return a "const char *".
It could return a NullTerminatedStringRef if there was such a thing, but when
that was proposed the decision was to just uses "const char*" for that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210062 91177308-0d34-0410-b5e6-96231b3b80d8
2014-06-03 02:41:57 +00:00
Rafael Espindola
ad6d7f58c7 Delete getAliasedGlobal.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209040 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-16 22:37:03 +00:00
Craig Topper
c34a25d59d [C++] Use 'nullptr'.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207394 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-28 04:05:08 +00:00
Craig Topper
e703fcb975 [C++] Use 'nullptr'.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207083 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-24 06:44:33 +00:00
Chandler Carruth
0d338a59bd [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE
definition below all the header #include lines. This updates most of the
miscellaneous other lib/... directories. A few left though.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206845 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-22 03:04:17 +00:00
Lang Hames
c3097bfd9b [ExecutionEngine] Allow JIT clients to enable/disable module verification.
Previously module verification was always enabled, with no way to turn it off.
As of this commit, module verification is on by default in Debug builds, and off
by default in release builds. The default behaviour can be overridden by calling
setVerifyModules(bool) on the JIT instance (this works for both the old JIT, and
MCJIT).

<rdar://problem/16150008>



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206561 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-18 06:48:23 +00:00
Chandler Carruth
b9a99d4593 [Allocator] Finally, finish nuking the redundant code that led me here
by removing the MallocSlabAllocator entirely and just using
MallocAllocator directly. This makes all off these allocators expose and
utilize the same core interface.

The only ugly part of this is that it exposes the fact that the JIT
allocator has no real handling of alignment, any more than the malloc
allocator does. =/ It would be nice to fix both of these to support
alignments, and then to leverage that in the BumpPtrAllocator to do less
over allocation in order to manually align pointers. But, that's another
patch for another day. This patch has no functional impact, it just
removes the somewhat meaningless wrapper around MallocAllocator.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206267 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-15 09:44:09 +00:00
Chandler Carruth
17f9c2e35b [Allocator] Make the underlying allocator a template instead of an
abstract interface. The only user of this functionality is the JIT
memory manager and it is quite happy to have a custom type here. This
removes a virtual function call and a lot of unnecessary abstraction
from the common case where this is just a *very* thin vaneer around
a call to malloc.

Hopefully still no functionality changed here. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206149 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-14 05:11:27 +00:00
Chandler Carruth
cb7ead25c2 [Allocator] Switch the BumpPtrAllocator to use a vector of pointers to
slabs rather than embedding a singly linked list in the slabs
themselves. This has a few advantages:

- Better utilization of the slab's memory by not wasting 16-bytes at the
  front.
- Simpler allocation strategy by not having a struct packed at the
  front.
- Avoids paging every allocated slab in just to traverse them for
  deallocating or dumping stats.

The latter is the really nice part. Folks have complained from time to
time bitterly that tearing down a BumpPtrAllocator, even if it doesn't
run any destructors, pages in all of the memory allocated. Now it won't.
=]

Also resolves a FIXME with the scaling of the slab sizes. The scaling
now disregards specially sized slabs for allocations larger than the
threshold.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206147 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-14 03:55:11 +00:00
Chandler Carruth
368a977298 [Allocator] Lift the slab size and size threshold into template
parameters rather than runtime parameters.

There is only one user of these parameters and they are compile time for
that user. Making these compile time seems to better reflect their
intended usage as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205143 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-30 12:07:07 +00:00
Chandler Carruth
ec90ab499d [cleanup] Hoist the initialization and constants for slab sizes to the
top of the default jit memory manager. This will allow them to be used
as template parameters rather than runtime parameters in a subsequent
commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204992 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-28 08:53:08 +00:00
Rafael Espindola
f165cf7ce8 Prevent alias from pointing to weak aliases.
This adds back r204781.

Original message:

Aliases are just another name for a position in a file. As such, the
regular symbol resolutions are not applied. For example, given

define void @my_func() {
  ret void
}
@my_alias = alias weak void ()* @my_func
@my_alias2 = alias void ()* @my_alias

We produce without this patch:

        .weak   my_alias
my_alias = my_func
        .globl  my_alias2
my_alias2 = my_alias

That is, in the resulting ELF file my_alias, my_func and my_alias are
just 3 names pointing to offset 0 of .text. That is *not* the
semantics of IR linking. For example, linking in a

@my_alias = alias void ()* @other_func

would require the strong my_alias to override the weak one and
my_alias2 would end up pointing to other_func.

There is no way to represent that with aliases being just another
name, so the best solution seems to be to just disallow it, converting
a miscompile into an error.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204934 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-27 15:26:56 +00:00
Rafael Espindola
72db10a995 Revert "Prevent alias from pointing to weak aliases."
This reverts commit r204781.

I will follow up to with msan folks to see what is what they
were trying to do with aliases to weak aliases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204784 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-26 06:14:40 +00:00
Rafael Espindola
33845aa8c4 Prevent alias from pointing to weak aliases.
Aliases are just another name for a position in a file. As such, the
regular symbol resolutions are not applied. For example, given

define void @my_func() {
  ret void
}
@my_alias = alias weak void ()* @my_func
@my_alias2 = alias void ()* @my_alias

We produce without this patch:

        .weak   my_alias
my_alias = my_func
        .globl  my_alias2
my_alias2 = my_alias

That is, in the resulting ELF file my_alias, my_func and my_alias are
just 3 names pointing to offset 0 of .text. That is *not* the
semantics of IR linking. For example, linking in a

@my_alias = alias void ()* @other_func

would require the strong my_alias to override the weak one and
my_alias2 would end up pointing to other_func.

There is no way to represent that with aliases being just another
name, so the best solution seems to be to just disallow it, converting
a miscompile into an error.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204781 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-26 04:48:47 +00:00
Craig Topper
838cb749dc [C++11] Add 'override' keyword to virtual methods that override their base class.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203344 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-08 07:51:20 +00:00
Ahmed Charles
f4ccd11075 Replace OwningPtr<T> with std::unique_ptr<T>.
This compiles with no changes to clang/lld/lldb with MSVC and includes
overloads to various functions which are used by those projects and llvm
which have OwningPtr's as parameters. This should allow out of tree
projects some time to move. There are also no changes to libs/Target,
which should help out of tree targets have time to move, if necessary.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203083 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-06 05:51:42 +00:00
Chandler Carruth
f4ec8bfaec [Layering] Move DebugInfo.h into the IR library where its implementation
already lives.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203046 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-06 00:46:21 +00:00
Chandler Carruth
7225e27b4c [Modules] Move ValueMap to the IR library. While this class does not
directly care about the Value class (it is templated so that the key can
be any arbitrary Value subclass), it is in fact concretely tied to the
Value class through the ValueHandle's CallbackVH interface which relies
on the key type being some Value subclass to establish the value handle
chain.

Ironically, the unittest is already in the right library.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202824 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-04 11:26:31 +00:00
Chandler Carruth
eb3d76da81 [Modules] Move ValueHandle into the IR library where Value itself lives.
Move the test for this class into the IR unittests as well.

This uncovers that ValueMap too is in the IR library. Ironically, the
unittest for ValueMap is useless in the Support library (honestly, so
was the ValueHandle test) and so it already lives in the IR unittests.
Mmmm, tasty layering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202821 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-04 11:17:44 +00:00
Rafael Espindola
356deb5ecd Use DataLayout from the module when easily available.
Eventually DataLayoutPass should go away, but for now that is the only easy
way to get a DataLayout in some APIs. This patch only changes the ones that
have easy access to a Module.

One interesting issue with sometimes using DataLayoutPass and sometimes
fetching it from the Module is that we have to make sure they are equivalent.
We can get most of the way there by always constructing the pass with a Module.
In fact, the pass could be changed to point to an external DataLayout instead
of owning one to make this stricter.

Unfortunately, the C api passes a DataLayout, so it has to be up to the caller
to make sure the pass and the module are in sync.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202204 91177308-0d34-0410-b5e6-96231b3b80d8
2014-02-25 23:25:17 +00:00
Rafael Espindola
57edc9d4ff Make DataLayout a plain object, not a pass.
Instead, have a DataLayoutPass that holds one. This will allow parts of LLVM
don't don't handle passes to also use DataLayout.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202168 91177308-0d34-0410-b5e6-96231b3b80d8
2014-02-25 17:30:31 +00:00
Juergen Ributzka
9ce88db752 Add target analysis passes to the codegen pipeline for MCJIT.
This patch adds the target analysis passes (usually TargetTransformInfo) to the
codgen pipeline. We also expose now the AddAnalysisPasses method through the C
API, because the optimizer passes would also benefit from better target-specific
cost models.

Reviewed by Andrew Kaylor

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199926 91177308-0d34-0410-b5e6-96231b3b80d8
2014-01-23 19:23:28 +00:00
NAKAMURA Takumi
0d87d72fa7 Prune redundant dependencies in LLVMBuild.txt.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196988 91177308-0d34-0410-b5e6-96231b3b80d8
2013-12-11 00:30:57 +00:00
Andrew Kaylor
1ab6084c9e Resolve JIT runtime linking problems on Android.
Patch by James Lyon!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194832 91177308-0d34-0410-b5e6-96231b3b80d8
2013-11-15 17:59:43 +00:00
Rafael Espindola
d0acc84b2b Remove dead code.
Support for exception handling in the legacy JIT was removed in r181354 and
this code was dead since then.

Thanks to Yaron Keren for noticing it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192101 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-07 13:54:50 +00:00
Filip Pizlo
6eb43d2956 This threads SectionName through the allocateCodeSection/allocateDataSection APIs, both in C++ and C land.
It's useful for the memory managers that are allocating a section to know what the name of the section is.  
At a minimum, this is useful for low-level debugging - it's customary for JITs to be able to tell you what 
memory they allocated, and as part of any such dump, they should be able to tell you some meta-data about 
what each allocation is for.  This allows clients that supply their own memory managers to do this.  
Additionally, we also envision the SectionName being useful for passing meta-data from within LLVM to an LLVM 
client.

This changes both the C and C++ APIs, and all of the clients of those APIs within LLVM.  I'm assuming that 
it's safe to change the C++ API because that API is allowed to change.  I'm assuming that it's safe to change 
the C API because we haven't shipped the API in a release yet (LLVM 3.3 doesn't include the MCJIT memory 
management C API).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191804 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-02 00:59:25 +00:00
Sylvestre Ledru
47c7eee533 Fix the build issue under ia64. Close bug #5715
Thanks to Luca Falavigna for the help and most of the patch.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@189324 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-27 06:49:46 +00:00
Elena Demikhovsky
e5cb25f860 Fixed alignment of code sections in the JIT mode. Added a test to the JITMemoryManager.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185421 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-02 12:24:22 +00:00
David Tweed
abb38fe8de Minor changes to the MCJITTest unittests to use the correct API for finalizing
the JIT object (including XFAIL an ARM test that now needs fixing). Also renames
internal function for consistency.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182085 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-17 10:01:46 +00:00
Rafael Espindola
01a21b3379 Remove dead code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181649 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-10 23:34:51 +00:00
Rafael Espindola
e449654815 Remove exception handling support from the old JIT.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181354 91177308-0d34-0410-b5e6-96231b3b80d8
2013-05-07 20:53:59 +00:00
Tim Northover
0a29cb0454 Make APFloat constructor require explicit semantics.
Previously we tried to infer it from the bit width size, with an added
IsIEEE argument for the PPC/IEEE 128-bit case, which had a default
value. This default value allowed bugs to creep in, where it was
inappropriate.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173138 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-22 09:46:31 +00:00
David Greene
fe1215ef93 Fix More Casts
Properly cast some more code that triggered cast-away-const errors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172469 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-14 21:04:44 +00:00
Eli Bendersky
dced3cdb04 Fix bug in exception table allocation (PR13678)
Patch by Michael Muller.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172214 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-11 16:33:30 +00:00
Chandler Carruth
0b8c9a80f2 Move all of the header files which are involved in modelling the LLVM IR
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.

There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.

The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.

I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).

I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171366 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-02 11:36:10 +00:00
Roman Divacky
38b06020db Remove duplicate includes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170902 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-21 17:06:44 +00:00
Chandler Carruth
d04a8d4b33 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 16:50:05 +00:00
Andrew Kaylor
53608a34ce Interface changes to allow RuntimeDyld memory managers to set memory permissions after an object has been loaded.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168114 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-15 23:50:01 +00:00
Chandler Carruth
426c2bf5cd Revert the majority of the next patch in the address space series:
r165941: Resubmit the changes to llvm core to update the functions to
         support different pointer sizes on a per address space basis.

Despite this commit log, this change primarily changed stuff outside of
VMCore, and those changes do not carry any tests for correctness (or
even plausibility), and we have consistently found questionable or flat
out incorrect cases in these changes. Most of them are probably correct,
but we need to devise a system that makes it more clear when we have
handled the address space concerns correctly, and ideally each pass that
gets updated would receive an accompanying test case that exercises that
pass specificaly w.r.t. alternate address spaces.

However, from this commit, I have retained the new C API entry points.
Those were an orthogonal change that probably should have been split
apart, but they seem entirely good.

In several places the changes were very obvious cleanups with no actual
multiple address space code added; these I have not reverted when
I spotted them.

In a few other places there were merge conflicts due to a cleaner
solution being implemented later, often not using address spaces at all.
In those cases, I've preserved the new code which isn't address space
dependent.

This is part of my ongoing effort to clean out the partial address space
code which carries high risk and low test coverage, and not likely to be
finished before the 3.2 release looms closer. Duncan and I would both
like to see the above issues addressed before we return to these
changes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167222 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-01 09:14:31 +00:00
Micah Villmow
2c39b15073 Resubmit the changes to llvm core to update the functions to support different pointer sizes on a per address space basis.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165941 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 16:24:29 +00:00
Sean Silva
8ac1995456 Remove buggy classof().
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165764 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-11 23:30:38 +00:00
Micah Villmow
fb384d61c7 Revert 165732 for further review.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165747 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-11 21:27:41 +00:00
Micah Villmow
f3840d2c16 Add in the first iteration of support for llvm/clang/lldb to allow variable per address space pointer sizes to be optimized correctly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165726 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-11 17:21:41 +00:00
Micah Villmow
3574eca1b0 Move TargetData to DataLayout.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165402 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-08 16:38:25 +00:00
Craig Topper
96601ca332 Add a getName function to MachineFunction. Use it in places that previously did getFunction()->getName(). Remove includes of Function.h that are no longer needed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162347 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-22 06:07:19 +00:00