Allow callers of `Value::print()` and `Metadata::print()` to pass in a
`ModuleSlotTracker`. This allows them to pay only once for calculating
module-level slots (such as Metadata).
This is related to PR23865, where there was a huge cost for
`MachineFunction::print()`. Although I don't have a *particular* user
in mind for this new code, I have hit big slowdowns before when running
`opt -debug`, and I think this will be useful. Going forward, if
someone hits a big slowdown with `print()` statements, they can create a
`ModuleSlotTracker` and send it through. Similarly, adding support to
`Value::dump()` and `Metadata::dump()` should be trivial.
I added unit tests to be sure the `print()` functions actually behave
the same way with and without the slot tracker.
llvm-svn: 240867
For another 1% speedup on the testcase in PR23865, push the
`ModuleSlotTracker` through to metadata-related printing in
`MachineBasicBlock::print()`.
llvm-svn: 240848
Expose enough of the IR-level `SlotTracker` so that
`MachineFunction::print()` can use a single one for printing
`BasicBlock`s. Next step would be to lift this through a few more APIs
so that we can make other print methods faster.
Fixes PR23865, changing the runtime of `llc -print-machineinstrs` from
many minutes (killed after 3 minutes, but it wasn't very close) to
13 seconds for a 502185 line dump.
llvm-svn: 240842
We support invoking a subset of llvm's intrinsics, but the verifier didn't account for this. We had previously added a special case to verify invokes of statepoints. By generalizing the code in terms of CallSite, we can verify invokes of other intrinsics as well. Interestingly, this found one test case which was invalid.
Note: I'm deliberately leaving the naming change from CI to CS to a follow up change. That will happen shortly, I just wanted to reduce the diff to make it clear what was happening with this one.
Differential Revision: http://reviews.llvm.org/D10118
llvm-svn: 240836
This is part of the work to devirtualize Value.
The old pattern was to call replaceUsesOfWithOnConstant which was overridden by
subclasses. Those could then call replaceUsesOfWithOnConstantImpl on Constant
to handle deleting the current value.
To be consistent with other parts of the code, this has been changed so that we
call the method on Constant, and that dispatches to an Impl on subclasses.
As part of this, it made sense to rename the methods to be more descriptive. The
new name is Constant::handleOperandChange, and it requires that all subclasses of
Constant implement handleOperandChangeImpl, even if they just throw an error if
they shouldn't be called.
Reviewed by Duncan Exon Smith.
llvm-svn: 240567
The only caller of this method is Value::replaceAllUsesWith which
explicitly checks that we are not a GlobalValue. So replace the
body with an unreachable to ensure that we never call it.
The unreachable itself is moved to GlobalValue not GlobalVariable
as that is the base class of all the globals we don't want to call
this method on.
Note, this patch is short lived as i'll soon refactor all callers
of this method.
llvm-svn: 240486
This reorganizes destroyConstant and destroyConstantImpl.
Now there is only destroyConstant in Constant itself, while
subclasses are required to implement destroyConstantImpl.
destroyConstantImpl no longer calls delete but is instead only
responsible for removing the constant from any maps in which it
is contained.
Reviewed by Duncan Exon Smith.
llvm-svn: 240471
The summary is that it moves the mangling earlier and replaces a few
calls to .addExternalSymbol with addSym.
I originally wanted to replace all the uses of addExternalSymbol with
addSym, but noticed it was a lot of work and doesn't need to be done
all at once.
llvm-svn: 240395
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!
llvm-svn: 240137
Summary:
Currently intrinsics don't affect the creation of the call graph.
This is not accurate with respect to statepoint and patchpoint
intrinsics -- these do call (or invoke) LLVM level functions.
This change fixes this inconsistency by adding a call to the external
node for call sites that call these non-leaf intrinsics. This coupled
with the fact that these intrinsics also escape the function pointer
they call gives us a conservatively correct call graph.
Reviewers: reames, chandlerc, atrick, pgavlin
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10526
llvm-svn: 240039
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
llvm-svn: 239940
If globals can be unnamed, there is no reason for aliases to be different.
The restriction was there since the original implementation in r36435. I
can only guess it was there because of the old bison parser for the old
alias syntax.
llvm-svn: 239921
Adds static_asserts to ensure alignment of concatenated objects is
correct, and fixes them where they are not.
Also changes the definition of AlignOf to use constexpr, except on
MSVC, to avoid enum comparison warnings from GCC.
(There's not too much of this in llvm itself, most of the fun is in
clang).
This seems to make LLVM actually work without Bus Error on 32bit
sparc.
Differential Revision: http://reviews.llvm.org/D10271
llvm-svn: 239872
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
llvm-svn: 239761
This commit connects the machine function analysis pass (which creates machine
functions) to the MIR parser, which will initialize the machine functions
with the state from the MIR file and reconstruct the machine IR.
This commit introduces a new interface called 'MachineFunctionInitializer',
which can be used to provide custom initialization for the machine functions.
This commit also introduces a new diagnostic class called
'DiagnosticInfoMIRParser' which is used for MIR parsing errors.
This commit modifies the default diagnostic handling in LLVMContext - now the
the diagnostics are printed directly into llvm::errs() so that the MIR parsing
errors can be printed with colours.
Reviewers: Justin Bogner
Differential Revision: http://reviews.llvm.org/D9928
llvm-svn: 239753
In the glorious future of opaque pointer types, it won't be possible to
retrieve the pointee type of a pointer type which is what's being done
in this GEP loop - but the first iteration is always a pointer type and
the loop doesn't care about that case, except whether or not the index
is a constant.
So pull that special case out before the loop and start at the second
iteration (index 1) instead.
Originally committed in r236670 and reverted with a test case in
r239015. This change keeps the test case working while also avoiding
depending on pointee types.
llvm-svn: 239629
For hung off uses, we need a Use* to tell use where the operands are.
This was User::OperandList but we want to remove that to save space
of all subclasses which aren't making use of 'hung off uses'.
Hung off uses now allocate their own 'OperandList' Use* in the
User::new which they call.
getOperandList() now uses the hung off uses bit to work out where the
Use* for the OperandList lives. If a User has hung off uses, then this
bit tells them to go back a single Use* from the User* and use that
value as the OperandList.
If a User has no hung off uses, then we get the first operand by
subtracting (NumOperands * sizeof(Use)) from the User this pointer.
This saves a pointer from User and all subclasses. Given the average
size of a subclass of User is 112 or 128 bytes, this saves around 7% of space
With malloc tending to align to 16-bytes the real saving is typically more like 3.5%.
On 'opt -O2 verify-uselistorder.lto.bc', peak memory usage prior to this change
is 149MB and after is 143MB so the savings are around 2.5% of peak.
Looking at some passes which allocate many Instructions and Values, parseIR drops
from 54.25MB to 52.21MB while the Inliner calls to Instruction::clone() drops
from 28.20MB to 27.05MB.
Reviewed by Duncan Exon Smith.
llvm-svn: 239623
There are now 2 versions of User::new. The first takes a size_t and is the current
implementation for subclasses which need 0 or more Use's allocated for their operands.
The new version takes no extra arguments to say that this subclass needs 'hung off uses'.
The HungOffUses bool is now set in this version of User::new and we can assert in
allocHungOffUses that we are allowed to have hung off uses.
This ensures we call the correct version of User::new for subclasses which need hung off uses.
A future commit will then allocate space for a single Use* which will be used
in place of User::OperandList once that field has been removed.
Reviewed by Duncan Exon Smith.
llvm-svn: 239622
This is to try make it very clear that subclasses shouldn't be changing
the value directly. Now that OperandList for normal instructions is computed
using the NumOperands, its critical that the NumOperands is accurate or we
could compute the wrong offset to the first operand.
I looked over all places which update NumOperands and they are all safe.
Hung off use User's don't use NumOperands to compute the OperandList so they
are safe to continue to manipulate it. The only other User which changed it
was GlobalVariable which has an optional init list but always allocated space
for a single Use. It was correctly setting NumOperands to 1 before setting an
initializer, and setting it to 0 after clearing the init list, so the order was safe.
Added some comments to that code to make sure that this isn't changed in future
without being aware of this constraint.
Reviewed by Duncan Exon Smith.
llvm-svn: 239621
We don't want anyone to access OperandList directly as its going to be removed
and computed instead. This uses getter's and setter's instead in which we
can later change the underlying implementation of OperandList.
Reviewed by Duncan Exon Smith.
llvm-svn: 239620
This improves debug locations in passes that do a lot of basic block
transformations. Important case is LoopUnroll pass, the test for correct
debug locations accompanies this change.
Test Plan: regression test suite
Reviewers: dblaikie, sanjoy
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D10367
llvm-svn: 239551
This reverts commit r239437.
This broke clang-cl self-hosts. We'd end up calling the __imp_ symbol
directly instead of using it to do an indirect function call.
llvm-svn: 239502
PhiNode, SwitchInst, LandingPad and IndirectBr all had virtually identical
logic for growing the hung off uses.
Move it to User so that they can all call a single shared implementation.
Their destructors were all empty after this change and were deleted. They all
have virtual clone_impl methods which can be used as vtable anchors.
Reviewed by Duncan Exon Smith.
llvm-svn: 239492
Now that the subclasses which care about hung off uses let ~User clean it up,
there's no need for a separate method. Just inline it to ~User and delete it.
Reviewed by Duncan Exon Smith.
llvm-svn: 239491
Currently all of the logic for deleting hung off uses, which PHI/switch/etc use,
is in their classes.
This adds a bit to Value which tracks whether that user had hung off uses,
then User can be responsible for clearing them instead of the sub classes.
Note, the bit used here was taken from NumOperands which was 30-bits.
Given the reduction to 29 bits, and the average User being just over 100 bytes,
a single User with 29-bits of num operands would need 50GB of RAM for itself
so its reasonable to assume that 29-bits is enough for now.
This is a step towards hiding all the hung off uses logic in the User.
Reviewed by Duncan Exon Smith.
llvm-svn: 239490
PhiNode's need to allocate space for an array of Use[N] and then BasicBlock*[N].
They had their own allocHungOffUses to handle all of this. This moves the logic
in to User::allocHungOffUses and PhiNode passes in a bool to say to allocate
the BB* space too.
Reviewed by Duncan Exon Smith.
llvm-svn: 239489
If the first argument to a function is a 'this' argument and the second
has the sret attribute, the ArgumentPromotion pass may promote the 'this'
argument to more than one argument, violating the IR constraint that 'sret'
may only be applied to the first or second argument.
Although this IR constraint is arguably unnecessary, it highlighted the fact
that ArgPromotion does not need to preserve this attribute. Dropping the
attribute reduces register pressure in the backend by avoiding the register
copy required by sret. Because sret implies noalias, we also replace the
former with the latter.
Differential Revision: http://reviews.llvm.org/D10353
llvm-svn: 239488
