Commit Graph

118469 Commits

Author SHA1 Message Date
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
Diego Novillo
3f53fc8f5f Fix PR 23525 - Separate header mass propagation in irregular loops.
Summary:
When propagating mass through irregular loops, the mass flowing through
each loop header may not be equal. This was causing wrong frequencies
to be computed for irregular loop headers.

Fixed by keeping track of masses flowing through each of the headers in
an irregular loop. To do this, we now keep track of per-header backedge
weights. After the loop mass is distributed through the loop, the
backedge weights are used to re-distribute the loop mass to the loop
headers.

Since each backedge will have a mass proportional to the different
branch weights, the loop headers will end up with a more approximate
weight distribution (as opposed to the current distribution that assumes
that every loop header is the same).

Reviewers: dexonsmith

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D10348

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239843 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 19:10:58 +00:00
Igor Laevsky
bfbac55e4e [Statepoints] Test only change. Check that statepoint lowering didn't generate more than expected amount of spills.
See http://reviews.llvm.org/D10402 for related discussion.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239842 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 19:07:05 +00:00
Matthias Braun
944aaeb28b VirtRegMap: Add undef flag when reading undefined subregisters.
While completely undefined registers are easy to catch and get their
<undef> flag early in ProcessImplicitDefs/RegisterCoalescer reading from
a partially defined register where just the subreg happens to be
undefined is harder to catch so we only add the undef flag in the
virtual register rewriting step.

No testcase as I cannot reproduce the problem on any of the in-tree targets at
the moment.

This fixes rdar://21387089

Differential Revision: http://reviews.llvm.org/D10470

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239838 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 18:22:28 +00:00
Matthias Braun
ff881427ec TargetRegisterInfo: Make the concept of imprecise lane masks explicit
LaneMasks as given by getSubRegIndexLaneMask() have a limited number of
of bits, so for targets with more than 31 disjunct subregister there may
be cases where:

   getSubReg(Reg,A) does not overlap getSubReg(Reg,B)

but we still have

   (getSubRegIndexLaneMask(A) & getSubRegIndexLaneMask(B)) != 0.

I had hoped to keep this an implementation detail of the tablegen but as
my next commit shows we can avoid unnecessary imp-defs operands if we
know that the lane masks in use are precise.

This is in preparation to http://reviews.llvm.org/D10470.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239837 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 18:22:26 +00:00
Reid Kleckner
8e206c19f4 [X86] Rename some frame lowering variables
Old names, new names, and what they really mean:

- IsWin64 -> IsWin64CC: This is true on non-Windows x86_64 platforms
  when the ms_abi calling convention is used.
- IsWinEH -> IsWin64Prologue: True when the target is Win64, regardless
  of calling convention. Changes the prologue to obey the constraints of
  the Win64 unwinder.
- NeedsWinEH -> NeedsWinCFI: We're using the win64 prologue *and* the we
  want .xdata unwind tables. Analogous to NeedsDwarfCFI.

NFC

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239836 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 18:08:57 +00:00
Tyler Nowicki
d4364d8c12 Rename Reduction variables/structures to Recurrence.
A reduction is a special kind of recurrence. In the loop vectorizer we currently
identify basic reductions. Future patches will extend this to identifying basic
recurrences.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239835 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 18:07:34 +00:00
Frederic Riss
37c67e6bb6 Have MachOObjectFile::isValidArch() accept armv7
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239833 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 17:37:03 +00:00
Alex Lorenz
d8a0ff34d9 MIR Parser: Report an error when a machine function doesn't have a corresponding function.
This commit reports an error when a machine function from a MIR file that contains
LLVM IR can't find a function with the same name in the loaded LLVM IR module.

Reviewers: Duncan P. N. Exon Smith

Differential Revision: http://reviews.llvm.org/D10468


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239831 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 17:06:29 +00:00
Rafael Espindola
0021a54ae5 Add a test for padded bitcode files.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239829 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 16:36:15 +00:00
Sanjay Patel
7ddee6601d propagate IR-level fast-math-flags to DAG nodes, disabled by default
This is an updated version of the patch that was checked in at:
http://reviews.llvm.org/rL237046

but subsequently reverted because it exposed a bug in the DAG Combiner:
http://reviews.llvm.org/D9893

This time, there's an enablement flag ("EnableFMFInDAG") around the code in
SelectionDAGBuilder where we copy the set of FP optimization flags from IR
instructions to DAG nodes. So, in theory, there should be no functional change
from this patch as-is, but it will allow testing with the added functionality
to proceed via "-enable-fmf-dag" passed to llc.

This patch adds the minimum plumbing necessary to use IR-level
fast-math-flags (FMF) in the backend without actually using
them for anything yet. This is a follow-on to:
http://reviews.llvm.org/rL235997

Differential Revision: http://reviews.llvm.org/D10403



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239828 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 16:25:43 +00:00
Kit Barton
1b26bfbef1 Properly handle the mftb instruction.
The mftb instruction was incorrectly marked as deprecated in the PPC
Backend. Instead, it should not be treated as deprecated, but rather be
implemented using the mfspr instruction. A similar patch was put into GCC last
year. Details can be found at:

https://sourceware.org/ml/binutils/2014-11/msg00383.html.
This change will replace instances of the mftb instruction with the mfspr
instruction for all CPUs except 601 and pwr3. This will also be the default
behaviour.

Additional details can be found in:

https://llvm.org/bugs/show_bug.cgi?id=23680

Phabricator review: http://reviews.llvm.org/D10419


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239827 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 16:01:15 +00:00
Colin LeMahieu
69266c3990 [Hexagon] Alphabetical ordering of functions, NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239826 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 15:59:53 +00:00
Matt Arsenault
5202cab841 Revert "Revert "Fix merges of non-zero vector stores""
Reapply r239539. Don't assume the collected number of
stores is the same vector size. Just take the first N
stores to fill the vector.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239825 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 15:51:48 +00:00
Daniel Sanders
ffb22b8d80 Clean up redundant copies of Triple objects. NFC
Summary:

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, rengolin, jholewinski

Differential Revision: http://reviews.llvm.org/D10382


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239823 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 15:44:21 +00:00
Benjamin Kramer
8a8bb45a76 [InstSimplify] Allow folding of fdiv X, X with just NaNs ignored
Any combination of +-inf/+-inf is NaN so it's already ignored with
nnan and we can skip checking for ninf. Also rephrase logic in comments
a bit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239821 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 14:57:29 +00:00
James Y Knight
cc73f10648 Repair cmake libatomic check.
The cmake check for whether libatomic could be used had been
unconditionally setting the result to false. Which was somewhat
fortunate, because the prerequisite check for whether it was *needed*
was always claiming it was, even if it was not.

However, this made platforms where libatomic is actually necessary
fail to link.

Differential Revision: http://reviews.llvm.org/D10453

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239819 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 14:00:01 +00:00
Daniel Sanders
b17a563e9a [mips][ias] Expand on r238751 to cover as many relocs as possible.
Summary:
Relocs that can be converted from absolute to PC-relative now do so if IsPCRel
is true. Relocs that require PC-relative now call llvm_unreachable() if IsPCRel
is false and similarly those that require absolute assert that IsPCRel is false.

Note that while it looks like some relocs (e.g. R_MIPS_26) can be converted into
the MIPS32r6/MIPS64r6 relocs (R_MIPS_PC*_S2), it isn't actually valid to do so.

Placeholders have been left in the testcase for unsupported relocs and relocs
that cannot be generated at the moment.

Reviewers: vkalintiris

Reviewed By: vkalintiris

Subscribers: llvm-commits, rafael

Differential Revision: http://reviews.llvm.org/D10184

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239817 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 13:46:26 +00:00
Daniel Sanders
7f5b833aa3 Replace string GNU Triples with llvm::Triple in TargetMachine::getTargetTriple(). NFC.
Summary:
This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, rengolin

Differential Revision: http://reviews.llvm.org/D10381


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239815 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 13:15:50 +00:00
Aaron Ballman
db8ece3bb7 Silence an MSVC warning about not all control paths returning a value; NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239814 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 13:14:59 +00:00
Daniel Sanders
0987211e24 Recommit r239721: Replace string GNU Triples with llvm::Triple in InitMCObjectFileInfo. NFC.
Summary:
This affects other tools so the previous C++ API has been retained as a
deprecated function for the moment. Clang has been updated with a trivial
patch (not covered by the pre-commit review) to avoid breaking -Werror builds.
Other in-tree tools will be fixed with similar patches.

This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

The first time this was committed it accidentally fixed an inconsistency in
triples in llvm-mc and this caused a failure. This inconsistency was fixed in
r239808.

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, rengolin

Differential Revision: http://reviews.llvm.org/D10366



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239812 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 12:18:07 +00:00
Toma Tabacu
e8601cf932 [mips] [IAS] Refactor symbol-address loading code into a helper function. NFC.
Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D9523

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239811 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 12:16:24 +00:00
Daniel Sanders
a8cc053519 [llvm-mc] The object form of the GNU triple should be the same as the string form.
Summary:
GetTarget() may modify TripleName without also updating TheTriple.
This can lead to situations where the MCObjectStreamer has a different triple
to the rest of LLVM.

This inconsistency caused sparc-little-endian.s to pass on Windows because most
of LLVM had sparcel-pc-win32 while MCObjectStreamer had "". I believe the same
kind of thing was also true of Darwin.

Reviewers: rengolin

Reviewed By: rengolin

Subscribers: llvm-commits, rengolin, rafael

Differential Revision: http://reviews.llvm.org/D10450

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239808 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 09:57:38 +00:00
Arnaud A. de Grandmaison
443838d8aa [MachineSink] Address post-commit review comments
The successors cache is now a local variable, making it more visible that it
is only valid for the MBB being processed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239807 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 08:57:21 +00:00
Asaf Badouh
7ae3494732 [AVX512] add integer min/max intrinsics support.
review:
http://reviews.llvm.org/D10439

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239806 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 08:39:27 +00:00
NAKAMURA Takumi
4ec9824e8c Disable llvm/test/CodeGen/MIR/machine-function.mir on x86 msc18 for now. Investigating.
The emission was as below;

  ---
  name:            foo
  alignment:       31428584
  exposesReturnsTwice: true
  hasInlineAsm:    false
  ...
  ---
  name:            bar
  alignment:       1701667182
  exposesReturnsTwice: false
  hasInlineAsm:    false
  ...
  ---
  name:            func
  alignment:       8
  exposesReturnsTwice: false
  hasInlineAsm:    false
  ...
  ---
  name:            func2
  alignment:       16
  exposesReturnsTwice: true
  hasInlineAsm:    true
  ...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239805 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 06:57:35 +00:00
NAKAMURA Takumi
f55aecb615 llvm/unittests/Support/Path.cpp: Use <windows.h> instead of <Windows.h>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239804 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 06:46:16 +00:00
Elena Demikhovsky
05e61f7113 X86: optimized i64 vector multiply with constant
When we multiply two 64-bit vectors, we extract lower and upper part and use the PMULUDQ instruction.
When one of the operands is a constant, the upper part may be zero, we know this at compile time.
Example: %a = mul <4 x i64> %b, <4 x i64> < i64 5, i64 5, i64 5, i64 5>.
I'm checking the value of the upper part and prevent redundant "multiply", "shift" and "add" operations.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239802 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 06:07:24 +00:00
Craig Topper
f428f1732a [TableGen] Remove unused method declaration. NFC
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239801 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 05:44:06 +00:00
Philip Reames
f8848a8149 Revert 239795
I forgot to update some clang test cases.  I'll fix and resubmit tomorrow.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239800 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 01:20:53 +00:00
Ahmed Bougacha
819a6b7d4b [AArch64] Generalize extract-high DUP extension to MOVI/MVNI.
These are really immediate DUPs, and suffer from the same problem
with long instructions with a high/2 variant (e.g. smull).

By extending a MOVI (or DUP, before this patch), we can avoid an ext
on the other operand of the long instruction, e.g. turning:
    ext.16b v0, v0, v0, #8
    movi.4h v1, #0x53
    smull.4s  v0, v0, v1
into:
    movi.8h v1, #0x53
    smull2.4s  v0, v0, v1

While there, add a now-necessary combine to fold (VT NVCAST (VT x)).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239799 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 01:18:14 +00:00
Ahmed Bougacha
d4521f1dd5 [AArch64] Robustize neon-2velem-high test. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239798 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 01:05:39 +00:00
Philip Reames
9426133890 Move logic from JumpThreading into LazyValue info to simplify caller.
This change is hopefully NFC. The only tricky part is that I changed the context instruction being used to the branch rather than the comparison. I believe both to be correct, but the branch is strictly more powerful. With the moved code, using the branch instruction is required for the basic block comparison test to return the same result. The previous code was able to directly access both the branch and the comparison where the revised code is not.

Differential Revision: http://reviews.llvm.org/D9652



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239797 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 00:49:59 +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
Philip Reames
6025d734a8 [InstCombine] Propagate non-null facts to call parameters
If a parameter to a function is known non-null, use the existing parameter attributes to record that fact at the call site. This has no optimization benefit by itself - that I know of - but is an enabling change for http://reviews.llvm.org/D9129.

Differential Revision: http://reviews.llvm.org/D9132



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239795 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 00:43:54 +00:00
Duncan P. N. Exon Smith
2648710555 modules: Mark CodeGen/DIEValues.def as a textual inclusion
Mark CodeGen/DIEValues.def as a textual inclusion to fix the
`LLVM_ENABLE_MODULES` build.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239794 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 00:43:52 +00:00
Duncan P. N. Exon Smith
4aee54eb95 modules: Move ProfileKinds to an anonymous namespace
Fix a build failure with `LLVM_ENABLE_MODULES` due to
`ProfileData::instr` conflicting with a function `instr()` in
`<curses.h>`.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239793 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 00:43:04 +00:00
Alex Lorenz
00b6413c97 MIR Serialization: Print and parse simple machine function attributes.
This commit serializes the simple, scalar attributes from the 
'MachineFunction' class.

Reviewers: Duncan P. N. Exon Smith

Differential Revision: http://reviews.llvm.org/D10449


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239790 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 00:10:47 +00:00
Alex Lorenz
b3607cdd97 MIR Serialization: move the MIR printer out of the MIR printing pass.
This commit decouples the MIR printer and the MIR printing pass so
that it will be possible to move the MIR printer into a separate 
machine IR library later on.

Reviewers: Duncan P. N. Exon Smith


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239788 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 23:52:35 +00:00
Reid Kleckner
46446a56b8 [X86] Try to shorten dwarf CFI emission
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239786 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 23:45:08 +00:00
Adrian Prantl
0f80e47db3 Debug Info IR: Switch DIObjCProperty to use DITypeRef.
This is a prerequisite for turning on ODR type uniquing for ObjC++.

rdar://problem/21377883

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239780 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 23:18:03 +00:00
Alex Lorenz
034945e8fe MIR Serialization: Create dummy functions when the MIR file doesn't have LLVM IR.
This commit creates a dummy LLVM IR function with one basic block and an unreachable
instruction for each parsed machine function when the MIR file doesn't have LLVM IR.
This change is required as the machine function analysis pass creates machine
functions only for the functions that are defined in the current LLVM module.

Reviewers: Duncan P. N. Exon Smith

Differential Revision: http://reviews.llvm.org/D10135


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239778 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 23:07:38 +00:00
Alex Lorenz
185789e9a0 MIR Serialization: Report an error when machine functions have the same name.
This commit reports an error when the MIR parser encounters a machine
function with the name that is the same as the name of a different
machine function.

Reviewers: Duncan P. N. Exon Smith

Differential Revision: http://reviews.llvm.org/D10130


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239774 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 22:23:23 +00:00
Peter Collingbourne
9784231221 Add safestack attribute to LLVMAttribute enum and Go bindings. Correct
constants in commented-out part of LLVMAttribute enum. Add tests that verify
that the safestack attribute is only allowed as a function attribute.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239772 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 22:16:51 +00:00
Colin LeMahieu
0d6057a14d [Hexagon] Using readobj rather than objdump.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239770 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 21:57:41 +00:00
Colin LeMahieu
c1344684c9 [Hexagon] PC-relative offsets are relative to packet start rather than the offset of the relocation. Set relocation addend and check it's correct in the ELF.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239769 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 21:52:13 +00:00
Simon Pilgrim
b1ce237a80 [X86][SSE] Added tests for vector i8/i16 to f32/f64 conversions
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239767 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-15 21:49:31 +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