Commit Graph

1031 Commits

Author SHA1 Message Date
Teresa Johnson
3011017ecc Restore "Function bitcode index in Value Symbol Table and lazy reading support"
This reverts commit r247898 (which reverted r247894).

Patch fixed to address two issues exposed by buildbots:
- unused variable warning in NDEBUG mode
- std::initializer_list lifetime issue causing test failures

Original Summary:
Support for including the function bitcode indices in the Value Symbol
Table. This requires writing the VST after the function blocks, which in
turn requires a new VST forward declaration record encoding the offset of
the full VST (which is backpatched to contain the offset after the VST
is written).

This patch also enables the lazy function reader to use the new function
indices out of the VST. This support will be used by ThinLTO as well, which
will be in a follow on patch. Backwards compatibility with older bitcode
files is maintained.

A new test is also included.

The bitcode format (used for the lazy reader as well as the upcoming
ThinLTO patches) came out of discussions with Duncan and others and is
described here:
https://drive.google.com/file/d/0B036uwnWM6RWdnBLakxmeDdOeXc/view

Reviewers: dexonsmith, davidxl, joker.eph

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12536

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247927 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-17 20:12:00 +00:00
Teresa Johnson
c9d578aaf4 Revert "Function bitcode index in Value Symbol Table and lazy reading support"
Temporarily revert to fix some buildbot issues. One is a minor issue
with a variable unused in NDEBUG mode. More concerning are some test
failures on win7 that I need to dig into.

This reverts commit 4e66a74543459832cfd571db42b4543580ae1d1d.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247898 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-17 16:19:10 +00:00
Teresa Johnson
1f05ba2fcb Function bitcode index in Value Symbol Table and lazy reading support
Summary:
Support for including the function bitcode indices in the Value Symbol
Table. This requires writing the VST after the function blocks, which in
turn requires a new VST forward declaration record encoding the offset of
the full VST (which is backpatched to contain the offset after the VST
is written).

This patch also enables the lazy function reader to use the new function
indices out of the VST. This support will be used by ThinLTO as well, which
will be in a follow on patch. Backwards compatibility with older bitcode
files is maintained.

A new test is also included.

The bitcode format (used for the lazy reader as well as the upcoming
ThinLTO patches) came out of discussions with Duncan and others and is
described here:
https://drive.google.com/file/d/0B036uwnWM6RWdnBLakxmeDdOeXc/view

Reviewers: dexonsmith, davidxl, joker.eph

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12536

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247894 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-17 15:52:30 +00:00
Teresa Johnson
daaec40323 Refactor string encoding checks in BitcodeWriter (NFC)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247891 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-17 14:37:35 +00:00
David Blaikie
2d35348660 Revert "[opaque pointer type] Pass GlobalAlias the actual pointer type rather than decomposing it into pointee type + address space"
This was a flawed change - it just caused the getElementType call to be
deferred until later, when we really need to remove it. Now that the IR
for GlobalAliases has been updated, the root cause is addressed that way
instead and this change is no longer needed (and in fact gets in the way
- because we want to pass the pointee type directly down further).

Follow up patches to push this through GlobalValue, bitcode format, etc,
will come along soon.

This reverts commit 236160.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247585 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-14 18:01:59 +00:00
Joseph Tremoulet
226889eb73 [WinEH] Add cleanupendpad instruction
Summary:
Add a `cleanupendpad` instruction, used to mark exceptional exits out of
cleanups (for languages/targets that can abort a cleanup with another
exception).  The `cleanupendpad` instruction is similar to the `catchendpad`
instruction in that it is an EH pad which is the target of unwind edges in
the handler and which itself has an unwind edge to the next EH action.
The `cleanupendpad` instruction, similar to `cleanupret` has a `cleanuppad`
argument indicating which cleanup it exits.  The unwind successors of a
`cleanuppad`'s `cleanupendpad`s must agree with each other and with its
`cleanupret`s.

Update WinEHPrepare (and docs/tests) to accomodate `cleanupendpad`.

Reviewers: rnk, andrew.w.kaylor, majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12433

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246751 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-03 09:09:43 +00:00
Filipe Cabecinhas
357ece4407 [BitcodeReader] Ensure we can read constant vector selects with an i1 condition
Summary:
Constant vectors weren't allowed to have an i1 condition in the
BitcodeReader. Make sure we have the same restrictions that are
documented, not more.

Reviewers: nlewycky, rafael, kschimpf

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12440

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246459 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-31 18:00:30 +00:00
Karl Schimpf
7a979ef11e Change comment to verify commit accesss.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246451 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-31 16:43:55 +00:00
Duncan P. N. Exon Smith
a5ae7c1c9f DI: Require subprogram definitions to be distinct
As a follow-up to r246098, require `DISubprogram` definitions
(`isDefinition: true`) to be 'distinct'.  Specifically, add an assembler
check, a verifier check, and bitcode upgrading logic to combat testcase
bitrot after the `DIBuilder` change.

While working on the testcases, I realized that
test/Linker/subprogram-linkonce-weak-odr.ll isn't relevant anymore.  Its
purpose was to check for a corner case in PR22792 where two subprogram
definitions match exactly and share the same metadata node.  The new
verifier check, requiring that subprogram definitions are 'distinct',
precludes that possibility.

I updated almost all the IR with the following script:

    git grep -l -E -e '= !DISubprogram\(.* isDefinition: true' |
    grep -v test/Bitcode |
    xargs sed -i '' -e 's/= \(!DISubprogram(.*, isDefinition: true\)/= distinct \1/'

Likely some variant of would work for out-of-tree testcases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246327 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-28 20:26:49 +00:00
David Majnemer
a354cd3ea5 [IR] Cleanup EH instructions a little bit
Just a cosmetic change, no functionality change is intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245818 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-23 19:22:31 +00:00
Joseph Tremoulet
d4a765f88a [WinEH] Require token linkage in EH pad/ret signatures
Summary:
WinEHPrepare is going to require that cleanuppad and catchpad produce values
of token type which are consumed by any cleanupret or catchret exiting the
pad.  This change updates the signatures of those operators to require/enforce
that the type produced by the pads is token type and that the rets have an
appropriate argument.

The catchpad argument of a `CatchReturnInst` must be a `CatchPadInst` (and
similarly for `CleanupReturnInst`/`CleanupPadInst`).  To accommodate that
restriction, this change adds a notion of an operator constraint to both
LLParser and BitcodeReader, allowing appropriate sentinels to be constructed
for forward references and appropriate error messages to be emitted for
illegal inputs.

Also add a verifier rule (noted in LangRef) that a catchpad with a catchpad
predecessor must have no other predecessors; this ensures that WinEHPrepare
will see the expected linear relationship between sibling catches on the
same try.

Lastly, remove some superfluous/vestigial casts from instruction operand
setters operating on BasicBlocks.

Reviewers: rnk, majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12108

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245797 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-23 00:26:33 +00:00
David Majnemer
de17e7736f [IR] Give catchret an optional 'return value' operand
Some personality routines require funclet exit points to be clearly
marked, this is done by producing a token at the funclet pad and
consuming it at the corresponding ret instruction.  CleanupReturnInst
already had a spot for this operand but CatchReturnInst did not.
Other personality routines don't need to use this which is why it has
been made optional.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245149 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-15 02:46:08 +00:00
David Majnemer
2dacece9e2 [IR] Add token types
This introduces the basic functionality to support "token types".
The motivation stems from the need to perform operations on a Value
whose provenance cannot be obscured.

There are several applications for such a type but my immediate
motivation stems from WinEH.  Our personality routine enforces a
single-entry - single-exit regime for cleanups.  After several rounds of
optimizations, we may be left with a terminator whose "cleanup-entry
block" is not entirely clear because control flow has merged two
cleanups together.  We have experimented with using labels as operands
inside of instructions which are not terminators to indicate where we
came from but found that LLVM does not expect such exotic uses of
BasicBlocks.

Instead, we can use this new type to clearly associate the "entry point"
and "exit point" of our cleanup.  This is done by having the cleanuppad
yield a Token and consuming it at the cleanupret.
The token type makes it impossible to obscure or otherwise hide the
Value, making it trivial to track the relationship between the two
points.

What is the burden to the optimizer?  Well, it turns out we have already
paid down this cost by accepting that there are certain calls that we
are not permitted to duplicate, optimizations have to watch out for
such instructions anyway.  There are additional places in the optimizer
that we will probably have to update but early examination has given me
the impression that this will not be heroic.

Differential Revision: http://reviews.llvm.org/D11861

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245029 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-14 05:09:07 +00:00
Yaron Keren
1a9ed33a8b Rangify for loop, NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244434 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-10 07:04:29 +00:00
Duncan P. N. Exon Smith
c61bc48acb DI: Disallow uniquable DICompileUnits
Since r241097, `DIBuilder` has only created distinct `DICompileUnit`s.
The backend is liable to start relying on that (if it hasn't already),
so make uniquable `DICompileUnit`s illegal and automatically upgrade old
bitcode.  This is a nice cleanup, since we can remove an unnecessary
`DenseSet` (and the associated uniquing info) from `LLVMContextImpl`.

Almost all the testcases were updated with this script:

    git grep -e '= !DICompileUnit' -l -- test |
    grep -v test/Bitcode |
    xargs sed -i '' -e 's,= !DICompileUnit,= distinct !DICompileUnit,'

I imagine something similar should work for out-of-tree testcases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243885 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-03 17:26:41 +00:00
Duncan P. N. Exon Smith
bf2040f00c DI: Remove DW_TAG_arg_variable and DW_TAG_auto_variable
Remove the fake `DW_TAG_auto_variable` and `DW_TAG_arg_variable` tags,
using `DW_TAG_variable` in their place Stop exposing the `tag:` field at
all in the assembly format for `DILocalVariable`.

Most of the testcase updates were generated by the following sed script:

    find test/ -name "*.ll" -o -name "*.mir" |
    xargs grep -l 'DILocalVariable' |
    xargs sed -i '' \
      -e 's/tag: DW_TAG_arg_variable, //' \
      -e 's/tag: DW_TAG_auto_variable, //'

There were only a handful of tests in `test/Assembly` that I needed to
update by hand.

(Note: a follow-up could change `DILocalVariable::DILocalVariable()` to
set the tag to `DW_TAG_formal_parameter` instead of `DW_TAG_variable`
(as appropriate), instead of having that logic magically in the backend
in `DbgVariable`.  I've added a FIXME to that effect.)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243774 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 18:58:39 +00:00
David Majnemer
4a45f0871a New EH representation for MSVC compatibility
This introduces new instructions neccessary to implement MSVC-compatible
exception handling support.  Most of the middle-end and none of the
back-end haven't been audited or updated to take them into account.

Differential Revision: http://reviews.llvm.org/D11097

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243766 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-31 17:58:14 +00:00
Bob Wilson
b25dcfd104 Reserve some constant values for the Swift calling convention.
Swift has a custom calling convention that also requires some new flags
on arguments and one new attribute on alloca instructions. This patch
does not include the implementation of that calling convention - that
will be provided as part of the open-source release of Swift; this only
reserves the bitcode constant values so that they are not used for
other purposes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@243379 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-28 04:05:45 +00:00
Igor Laevsky
6690dbffe0 Add argmemonly attribute.
This change adds new attribute called "argmemonly". Function marked with this attribute can only access memory through it's argument pointers. This attribute directly corresponds to the "OnlyAccessesArgumentPointees" ModRef behaviour in alias analysis.

Differential Revision: http://reviews.llvm.org/D10398



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241979 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-11 10:30:36 +00:00
James Molloy
ee0d992b07 Add support for fast-math flags to the FCmp instruction.
FCmp behaves a lot like a floating-point binary operator in many ways,
and can benefit from fast-math information. Flags such as nsz and nnan
can affect if this fcmp (in combination with a select) can be treated
as a fminnum/fmaxnum operation.

This adds backwards-compatible bitcode support, IR parsing and writing,
LangRef changes and IRBuilder changes. I'll need to audit InstSimplify
and InstCombine in a followup to find places where flags should be
copied.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241901 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-10 12:52:00 +00:00
David Majnemer
eddf9e2057 Revert the new EH instructions
This reverts commits r241888-r241891, I didn't mean to commit them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241893 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-10 07:15:17 +00:00
David Majnemer
751c4be705 New EH representation for MSVC compatibility
Summary:
This introduces new instructions neccessary to implement MSVC-compatible
exception handling support.  Most of the middle-end and none of the
back-end haven't been audited or updated to take them into account.

Reviewers: rnk, JosephTremoulet, reames, nlewycky, rjmccall

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D11041

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241888 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-10 07:00:44 +00:00
Filipe Cabecinhas
177fabfc30 Remove always-true comparison, NFC.
Summary:
Looking at r241279, I noticed that UpgradedIntrinsics only gets written
to in the following code:

    if (UpgradeIntrinsicFunction(&F, NewFn))
      UpgradedIntrinsics[&F] = NewFn;

Looking through UpgradeIntrinsicFunction, we always return false OR
NewFn will be set to a different function from our source.

This patch pulls the F != NewFn into UpgradeIntrinsicFunction as an
assert, and removes the check from callers of UpgradeIntrinsicFunction.

Reviewers: rafael, chandlerc

Subscribers: llvm-commits-list

Differential Revision: http://reviews.llvm.org/D10915

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241369 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-03 20:12:01 +00:00
Rafael Espindola
21afba1004 Avoid a use after free.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241345 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-03 12:20:34 +00:00
Rafael Espindola
9afb3a2589 Fix for PR23310: llvm-dis crashes when trying to upgrade an intrinsic.
When trying to upgrade @llvm.x86.sse2.psrl.dq while parsing a module,
BitcodeReader adds the function to its worklist twice, resulting in a
crash when accessing it the second time.

This patch replaces the worklist vector by a map.

Patch by Philip Pfaffe.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241281 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-02 16:22:40 +00:00
Rafael Espindola
002ff89e22 Rangify some loops.
Patch by Philip Pfaffe!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241279 91177308-0d34-0410-b5e6-96231b3b80d8
2015-07-02 15:55:09 +00:00
Adrian Prantl
717764717b Add a DIModule metadata node to the IR.
It is meant to be used to record modules @imported by the current
compile unit, so a debugger an import the same modules to replicate this
environment before dropping into the expression evaluator.

DIModule is a sibling to DINamespace and behaves quite similarly.
In addition to the name of the module it also records the module
configuration details that are necessary to uniquely identify the module.
This includes the configuration macros (e.g., -DNDEBUG), the include path
where the module.map file is to be found, and the isysroot.

The idea is that the backend will turn this into a DW_TAG_module.

http://reviews.llvm.org/D9614
rdar://problem/20965932

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241017 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-29 23:03:47 +00:00
Pete Cooper
5c09803aee Use foreach loop over constant operands. NFC.
A number of places had explicit loops over Constant::operands().
Just use foreach loops where possible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240694 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-25 20:51:38 +00:00
Alexander Kornienko
cd52a7a381 Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)
Apparently, the style needs to be agreed upon first.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240390 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-23 09:49:53 +00:00
Rafael Espindola
21a540abc4 Remove the IsStreamed member variable.
Having different code paths for streamed and regular bitcode reading was a
source of bugs in the past and this defines them away.

It has a small but noticeable impact on performance. I timed running
"opt -disable-output -disable-verify" on a ltoed clang. It goes from

14.752845231 seconds time elapsed   ( +-  0.16% )

to

15.012463721 seconds time elapsed   ( +-  0.11% )

Extracted from a patch by Karl Schimpf.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240305 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-22 18:06:15 +00:00
Alexander Kornienko
cf0db29df2 Fixed/added namespace ending comments using clang-tidy. NFC
The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240137 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-19 15:57:42 +00:00
Benjamin Kramer
3cab8a1193 [Bitcode] Replace hand-coded little endian handling with Endian.h functions.
No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239944 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-17 20:55:30 +00:00
David Majnemer
cc714e2142 Move the personality function from LandingPadInst to Function
The personality routine currently lives in the LandingPadInst.

This isn't desirable because:
- All LandingPadInsts in the same function must have the same
  personality routine.  This means that each LandingPadInst beyond the
  first has an operand which produces no additional information.

- There is ongoing work to introduce EH IR constructs other than
  LandingPadInst.  Moving the personality routine off of any one
  particular Instruction and onto the parent function seems a lot better
  than have N different places a personality function can sneak onto an
  exceptional function.

Differential Revision: http://reviews.llvm.org/D10429

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239940 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-17 20:52:32 +00:00
Rafael Espindola
cc625c9f25 Handle forward referenced function when streaming bitcode.
Without this the included unit test would assert in

  assert(BasicBlockFwdRefs.empty() && "Unresolved blockaddress fwd references");

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239871 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-17 01:15:47 +00:00
Rafael Espindola
485973a45e Handle MaterializeAll in getLazyBitcodeModuleImpl. NFC.
This just handles both cases in the same place.

Extracted from a patch by Karl Schimpf.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239870 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-17 00:40:56 +00:00
Rafael Espindola
4a4558e436 Use std::unique_ptr to manage the DataStreamer in bitcode parsing.
We were already deleting it, this just makes it explicit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239867 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 23:29:49 +00:00
Rafael Espindola
20a6785cd2 Return a unique_ptr from getLazyBitcodeModule and parseBitcodeFile. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239858 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 22:27:55 +00:00
Rafael Espindola
0c650627ca Improve handling of end of file in the bitcode reader.
Before this patch the bitcode reader would read a module from a file
that contained in order:

* Any number of non MODULE_BLOCK sub blocks.
* One MODULE_BLOCK
* Any number of non MODULE_BLOCK sub blocks.
* 4 '\n' characters to handle OS X's ranlib.

Since we support lazy reading of modules, any information that is relevant
for the module has to be in the MODULE_BLOCK or before it. We don't gain
anything from checking what is after.

This patch then changes the reader to stop once the MODULE_BLOCK has been
successfully parsed.

This avoids the ugly special case for .bc files in an archive and makes it
easier to embed bitcode files.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239845 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 20:03:39 +00:00
Duncan P. N. Exon Smith
5449852030 modules: Add explicit dependency on intrinsics_gen
`LLVM_ENABLE_MODULES` builds sometimes fail because `Intrinsics.td`
needs to regenerate `Instrinsics.h` before anyone can include anything
from the LLVM_IR module.  Represent the dependency explicitly to prevent
that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239796 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 00:44:12 +00:00
Peter Collingbourne
7ffec838a2 Protection against stack-based memory corruption errors using SafeStack
This patch adds the safe stack instrumentation pass to LLVM, which separates
the program stack into a safe stack, which stores return addresses, register
spills, and local variables that are statically verified to be accessed
in a safe way, and the unsafe stack, which stores everything else. Such
separation makes it much harder for an attacker to corrupt objects on the
safe stack, including function pointers stored in spilled registers and
return addresses. You can find more information about the safe stack, as
well as other parts of or control-flow hijack protection technique in our
OSDI paper on code-pointer integrity (http://dslab.epfl.ch/pubs/cpi.pdf)
and our project website (http://levee.epfl.ch).

The overhead of our implementation of the safe stack is very close to zero
(0.01% on the Phoronix benchmarks). This is lower than the overhead of
stack cookies, which are supported by LLVM and are commonly used today,
yet the security guarantees of the safe stack are strictly stronger than
stack cookies. In some cases, the safe stack improves performance due to
better cache locality.

Our current implementation of the safe stack is stable and robust, we
used it to recompile multiple projects on Linux including Chromium, and
we also recompiled the entire FreeBSD user-space system and more than 100
packages. We ran unit tests on the FreeBSD system and many of the packages
and observed no errors caused by the safe stack. The safe stack is also fully
binary compatible with non-instrumented code and can be applied to parts of
a program selectively.

This patch is our implementation of the safe stack on top of LLVM. The
patches make the following changes:

- Add the safestack function attribute, similar to the ssp, sspstrong and
  sspreq attributes.

- Add the SafeStack instrumentation pass that applies the safe stack to all
  functions that have the safestack attribute. This pass moves all unsafe local
  variables to the unsafe stack with a separate stack pointer, whereas all
  safe variables remain on the regular stack that is managed by LLVM as usual.

- Invoke the pass as the last stage before code generation (at the same time
  the existing cookie-based stack protector pass is invoked).

- Add unit tests for the safe stack.

Original patch by Volodymyr Kuznetsov and others at the Dependable Systems
Lab at EPFL; updates and upstreaming by myself.

Differential Revision: http://reviews.llvm.org/D6094

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239761 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 21:07:11 +00:00
Rafael Espindola
3aef7761ac Don't indent inside a namespace. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239760 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 21:04:27 +00:00
Rafael Espindola
132c3549d9 Replace @ with the more common \. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239759 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 21:02:49 +00:00
Rafael Espindola
9e26836221 Don't repeat names in comments and start functions with a lower case letter.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239756 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 20:55:37 +00:00
Rafael Espindola
1456b12847 Cleanup the constructor of BitcodeReader. NFC.
Use the same argument names as the members.
Use default member initializes.

Extracted from a patch by Karl Schimpf.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239749 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 20:08:17 +00:00
Yaron Keren
bffcf0d1c9 Rangify several for loops in ValueEnumerator constructor.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239636 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-12 20:18:20 +00:00
Yaron Keren
923bd1da56 Rangify two for loops in BitcodeReader.cpp.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239627 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-12 18:13:20 +00:00
Filipe Cabecinhas
ce986b6bc0 Use early return idiom. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239228 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-06 20:44:53 +00:00
Filipe Cabecinhas
a3a2cab504 [BitcodeReader] Diagnose type mismatches with aliases
Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238895 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-03 01:30:13 +00:00
Filipe Cabecinhas
287f68d654 [BitcodeReader] Check vector size before trying to create a VectorType
Bug found with AFL fuzz

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238891 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-03 00:05:30 +00:00
Filipe Cabecinhas
3b821159da [BitcodeReader] Change an assert to a call to a call to Error()
It's reachable from user input.

Bug found with AFL fuzz.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238633 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-30 00:17:20 +00:00