Commit Graph

81 Commits

Author SHA1 Message Date
Philip Reames f47a313e71 Add a transform pass to make the executable semantics of poison explicit in the IR
Implements a transform pass which instruments IR such that poison semantics are made explicit. That is, it provides a (possibly partial) executable semantics for every instruction w.r.t. poison as specified in the LLVM LangRef. There are obvious parallels to the sanitizer tools, but this pass is focused purely on the semantics of LLVM IR, not any particular source language.

The target audience for this tool is developers working on or targetting LLVM from a frontend. The idea is to be able to take arbitrary IR (with the assumption of known inputs), and evaluate it concretely after having made poison semantics explicit to detect cases where either a) the original code executes UB, or b) a transform pass introduces UB which didn't exist in the original program.

At the moment, this is mostly the framework and still needs to be fleshed out. By reusing existing code we have decent coverage, but there's a lot of cases not yet handled. What's here is good enough to handle interesting cases though; for instance, one of the recent LFTR bugs involved UB being triggered by integer induction variables with nsw/nuw flags would be reported by the current code.

(See comment in PoisonChecking.cpp for full explanation and context)

Differential Revision: https://reviews.llvm.org/D64215

llvm-svn: 365536
2019-07-09 18:49:29 +00:00
Roman Lebedev 7ad5d14f3a [NFC] Instruction: introduce replaceSuccessorWith() function, use it
Summary:
There is `Instruction::getNumSuccessors()`, `Instruction::getSuccessor()`
and `Instruction::setSuccessor()`, but no function to replace every
specified `BasicBlock*` successor with some other specified `BasicBlock*`.
I've found one place where it should clearly be used.

Reviewers: chandlerc, craig.topper, spatel, danielcdh

Reviewed By: craig.topper

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61010

llvm-svn: 359994
2019-05-05 18:59:22 +00:00
Wei Mi 01f8d556aa [PGO/SamplePGO][NFC] Move the function updateProfWeight from Instruction
to CallInst.

The issue was raised here: https://reviews.llvm.org/D60903#1472783

The function Instruction::updateProfWeight is only used for CallInst in
profile update. From the current interface, it is very easy to think that
the function can also be used for branch instruction. However, Branch
instruction does't need the scaling the function provides for
branch_weights and VP (value profile), in addition, scaling may introduce
inaccuracy for branch probablity.

The patch moves the function updateProfWeight from Instruction class to
CallInst to remove the confusion. The patch also changes the scaling of
branch_weights from a loop to a block because we know that ProfileData
for branch_weights of CallInst will only have two operands at most.

Differential Revision: https://reviews.llvm.org/D60911

llvm-svn: 358900
2019-04-22 17:04:51 +00:00
Craig Topper 784929d045 Implementation of asm-goto support in LLVM
This patch accompanies the RFC posted here:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/127239.html

This patch adds a new CallBr IR instruction to support asm-goto
inline assembly like gcc as used by the linux kernel. This
instruction is both a call instruction and a terminator
instruction with multiple successors. Only inline assembly
usage is supported today.

This also adds a new INLINEASM_BR opcode to SelectionDAG and
MachineIR to represent an INLINEASM block that is also
considered a terminator instruction.

There will likely be more bug fixes and optimizations to follow
this, but we felt it had reached a point where we would like to
switch to an incremental development model.

Patch by Craig Topper, Alexander Ivchenko, Mikhail Dvoretckii

Differential Revision: https://reviews.llvm.org/D53765

llvm-svn: 353563
2019-02-08 20:48:56 +00:00
Craig Topper 0b5e6b11c3 [IR] Use CallBase to reduce code duplication. NFC
Noticed in the asm-goto patch. Callbr needs to go here too. One cast and call is better than 3.

Differential Revision: https://reviews.llvm.org/D57295

llvm-svn: 352563
2019-01-29 23:31:54 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Vedant Kumar b264d69de7 [IR] Add Instruction::isLifetimeStartOrEnd, NFC
Instruction::isLifetimeStartOrEnd() checks whether an Instruction is an
llvm.lifetime.start or an llvm.lifetime.end intrinsic.

This was suggested as a cleanup in D55967.

Differential Revision: https://reviews.llvm.org/D56019

llvm-svn: 349964
2018-12-21 21:49:40 +00:00
Cameron McInally cbde0d9c7b [IR] Add a dedicated FNeg IR Instruction
The IEEE-754 Standard makes it clear that fneg(x) and
fsub(-0.0, x) are two different operations. The former is a bitwise
operation, while the latter is an arithmetic operation. This patch
creates a dedicated FNeg IR Instruction to model that behavior.

Differential Revision: https://reviews.llvm.org/D53877

llvm-svn: 346774
2018-11-13 18:15:47 +00:00
Carlos Alberto Enciso fa9cf89734 [DebugInfo][Dexter] Unreachable line stepped onto after SimplifyCFG.
In SimplifyCFG when given a conditional branch that goes to BB1 and BB2, the hoisted common terminator instruction in the two blocks, caused debug line records associated with subsequent select instructions to become ambiguous. It causes the debugger to display unreachable source lines.

Differential Revision: https://reviews.llvm.org/D53390

llvm-svn: 346481
2018-11-09 09:42:10 +00:00
Chandler Carruth 9ae926b973 [IR] Replace `isa<TerminatorInst>` with `isTerminator()`.
This is a bit awkward in a handful of places where we didn't even have
an instruction and now we have to see if we can build one. But on the
whole, this seems like a win and at worst a reasonable cost for removing
`TerminatorInst`.

All of this is part of the removal of `TerminatorInst` from the
`Instruction` type hierarchy.

llvm-svn: 340701
2018-08-26 09:51:22 +00:00
Chandler Carruth 96fc1de77d [IR] Begin removal of TerminatorInst by removing successor manipulation.
The core get and set routines move to the `Instruction` class. These
routines are only valid to call on instructions which are terminators.

The iterator and *generic* range based access move to `CFG.h` where all
the other generic successor and predecessor access lives. While moving
the iterator here, simplify it using the iterator utilities LLVM
provides and updates coding style as much as reasonable. The APIs remain
pointer-heavy when they could better use references, and retain the odd
behavior of `operator*` and `operator->` that is common in LLVM
iterators. Adjusting this API, if desired, should be a follow-up step.

Non-generic range iteration is added for the two instructions where
there is an especially easy mechanism and where there was code
attempting to use the range accessor from a specific subclass:
`indirectbr` and `br`. In both cases, the successors are contiguous
operands and can be easily iterated via the operand list.

This is the first major patch in removing the `TerminatorInst` type from
the IR's instruction type hierarchy. This change was discussed in an RFC
here and was pretty clearly positive:
http://lists.llvm.org/pipermail/llvm-dev/2018-May/123407.html

There will be a series of much more mechanical changes following this
one to complete this move.

Differential Revision: https://reviews.llvm.org/D47467

llvm-svn: 340698
2018-08-26 08:41:15 +00:00
Vedant Kumar f01827f2d1 [IR] Introduce helpers to skip debug instructions (NFC)
This patch introduces two helpers to make it easier to ignore debug
intrinsics:

- Instruction::getNextNonDebugInstruction()

This is just like Instruction::getNextNode(), except that it skips debug
info.

- skipDebugInfo(BasicBlock::iterator)

A free function which advances a BasicBlock iterator past any debug
info. This is a no-op when the iterator already points to a non-debug
instruction.

Part of: llvm.org/PR37728
Related to: https://reviews.llvm.org/D47874

Differential Revision: https://reviews.llvm.org/D48305

llvm-svn: 335083
2018-06-19 23:42:17 +00:00
Warren Ristow d3efa9429f [InstCombine] Enable more reassociations using FMF 'reassoc' + 'nsz'
Reassociation of math ops in some contexts (especially vector contexts)
has generally only been happening when the 'fast' FMF was set.  This
enables reassoication when only the finer grained controls 'reassoc' and
'nsz' are set.

Differential Revision: https://reviews.llvm.org/D47335

llvm-svn: 333221
2018-05-24 20:16:43 +00:00
Chris Bieneman abdea268c1 [IPSCCP] Remove calls without side effects
Summary:
When performing constant propagation for call instructions we have historically replaced all uses of the return from a call, but not removed the call itself. This is required for correctness if the calls have side effects, however the compiler should be able to safely remove calls that don't have side effects.

This allows the compiler to completely fold away calls to functions that have no side effects if the inputs are constant and the output can be determined at compile time.

Reviewers: davide, sanjoy, bruno, dberlin

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D38856

llvm-svn: 322125
2018-01-09 21:58:46 +00:00
Michael Zolotukhin f05cb4374d Remove redundant includes from lib/IR.
llvm-svn: 320622
2017-12-13 21:30:52 +00:00
Mandeep Singh Grang d104673257 [llvm] Remove redundant return [NFC]
Reviewers: davidxl, olista01, Eugene.Zelenko

Reviewed By: Eugene.Zelenko

Subscribers: sdardis, javed.absar, llvm-commits

Differential Revision: https://reviews.llvm.org/D39917

llvm-svn: 317995
2017-11-12 03:47:50 +00:00
Sanjay Patel 629c411538 [IR] redefine 'UnsafeAlgebra' / 'reassoc' fast-math-flags and add 'trans' fast-math-flag
As discussed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2016-November/107104.html
and again more recently:
http://lists.llvm.org/pipermail/llvm-dev/2017-October/118118.html

...this is a step in cleaning up our fast-math-flags implementation in IR to better match
the capabilities of both clang's user-visible flags and the backend's flags for SDNode.

As proposed in the above threads, we're replacing the 'UnsafeAlgebra' bit (which had the 
'umbrella' meaning that all flags are set) with a new bit that only applies to algebraic 
reassociation - 'AllowReassoc'.

We're also adding a bit to allow approximations for library functions called 'ApproxFunc' 
(this was initially proposed as 'libm' or similar).

...and we're out of bits. 7 bits ought to be enough for anyone, right? :) FWIW, I did 
look at getting this out of SubclassOptionalData via SubclassData (spacious 16-bits), 
but that's apparently already used for other purposes. Also, I don't think we can just 
add a field to FPMathOperator because Operator is not intended to be instantiated. 
We'll defer movement of FMF to another day.

We keep the 'fast' keyword. I thought about removing that, but seeing IR like this:
%f.fast = fadd reassoc nnan ninf nsz arcp contract afn float %op1, %op2
...made me think we want to keep the shortcut synonym.

Finally, this change is binary incompatible with existing IR as seen in the 
compatibility tests. This statement:
"Newer releases can ignore features from older releases, but they cannot miscompile 
them. For example, if nsw is ever replaced with something else, dropping it would be 
a valid way to upgrade the IR." 
( http://llvm.org/docs/DeveloperPolicy.html#ir-backwards-compatibility )
...provides the flexibility we want to make this change without requiring a new IR 
version. Ie, we're not loosening the FP strictness of existing IR. At worst, we will 
fail to optimize some previously 'fast' code because it's no longer recognized as 
'fast'. This should get fixed as we audit/squash all of the uses of 'isFast()'.

Note: an inter-dependent clang commit to use the new API name should closely follow 
commit.

Differential Revision: https://reviews.llvm.org/D39304

llvm-svn: 317488
2017-11-06 16:27:15 +00:00
Sanjay Patel 674d2c23ea [Instruction] add moveAfter() convenience function; NFCI
As suggested in D37121, here's a wrapper for removeFromParent() + insertAfter(),
but implemented using moveBefore() for symmetry/efficiency.

Differential Revision: https://reviews.llvm.org/D37239

llvm-svn: 312001
2017-08-29 14:07:48 +00:00
Konstantin Zhuravlyov bb80d3e1d3 Enhance synchscope representation
OpenCL 2.0 introduces the notion of memory scopes in atomic operations to
  global and local memory. These scopes restrict how synchronization is
  achieved, which can result in improved performance.

  This change extends existing notion of synchronization scopes in LLVM to
  support arbitrary scopes expressed as target-specific strings, in addition to
  the already defined scopes (single thread, system).

  The LLVM IR and MIR syntax for expressing synchronization scopes has changed
  to use *syncscope("<scope>")*, where <scope> can be "singlethread" (this
  replaces *singlethread* keyword), or a target-specific name. As before, if
  the scope is not specified, it defaults to CrossThread/System scope.

  Implementation details:
    - Mapping from synchronization scope name/string to synchronization scope id
      is stored in LLVM context;
    - CrossThread/System and SingleThread scopes are pre-defined to efficiently
      check for known scopes without comparing strings;
    - Synchronization scope names are stored in SYNC_SCOPE_NAMES_BLOCK in
      the bitcode.

Differential Revision: https://reviews.llvm.org/D21723

llvm-svn: 307722
2017-07-11 22:23:00 +00:00
George Burgess IV a20352e13e [LoopVectorize] Don't preserve nsw/nuw flags on shrunken ops.
If we're shrinking a binary operation, it may be the case that the new
operations wraps where the old didn't. If this happens, the behavior
should be well-defined. So, we can't always carry wrapping flags with us
when we shrink operations.

If we do, we get incorrect optimizations in cases like:

void foo(const unsigned char *from, unsigned char *to, int n) {
  for (int i = 0; i < n; i++)
    to[i] = from[i] - 128;
}

which gets optimized to:

void foo(const unsigned char *from, unsigned char *to, int n) {
  for (int i = 0; i < n; i++)
    to[i] = from[i] | 128;
}

Because:
- InstCombine turned `sub i32 %from.i, 128` into
  `add nuw nsw i32 %from.i, 128`.
- LoopVectorize vectorized the add to be `add nuw nsw <16 x i8>` with a
  vector full of `i8 128`s
- InstCombine took advantage of the fact that the newly-shrunken add
  "couldn't wrap", and changed the `add` to an `or`.

InstCombine seems happy to figure out whether we can add nuw/nsw on its
own, so I just decided to drop the flags. There are already a number of
places in LoopVectorize where we rely on InstCombine to clean up.

llvm-svn: 305053
2017-06-09 03:56:15 +00:00
Chandler Carruth 6bda14b313 Sort the remaining #include lines in include/... and lib/....
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.

I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.

This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.

Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).

llvm-svn: 304787
2017-06-06 11:49:48 +00:00
Reid Kleckner 96ab8726a3 [IR] De-virtualize ~Value to save a vptr
Summary:
Implements PR889

Removing the virtual table pointer from Value saves 1% of RSS when doing
LTO of llc on Linux. The impact on time was positive, but too noisy to
conclusively say that performance improved. Here is a link to the
spreadsheet with the original data:

https://docs.google.com/spreadsheets/d/1F4FHir0qYnV0MEp2sYYp_BuvnJgWlWPhWOwZ6LbW7W4/edit?usp=sharing

This change makes it invalid to directly delete a Value, User, or
Instruction pointer. Instead, such code can be rewritten to a null check
and a call Value::deleteValue(). Value objects tend to have their
lifetimes managed through iplist, so for the most part, this isn't a big
deal.  However, there are some places where LLVM deletes values, and
those places had to be migrated to deleteValue.  I have also created
llvm::unique_value, which has a custom deleter, so it can be used in
place of std::unique_ptr<Value>.

I had to add the "DerivedUser" Deleter escape hatch for MemorySSA, which
derives from User outside of lib/IR. Code in IR cannot include MemorySSA
headers or call the MemoryAccess object destructors without introducing
a circular dependency, so we need some level of indirection.
Unfortunately, no class derived from User may have any virtual methods,
because adding a virtual method would break User::getHungOffOperands(),
which assumes that it can find the use list immediately prior to the
User object. I've added a static_assert to the appropriate OperandTraits
templates to help people avoid this trap.

Reviewers: chandlerc, mehdi_amini, pete, dberlin, george.burgess.iv

Reviewed By: chandlerc

Subscribers: krytarowski, eraman, george.burgess.iv, mzolotukhin, Prazek, nlewycky, hans, inglorion, pcc, tejohnson, dberlin, llvm-commits

Differential Revision: https://reviews.llvm.org/D31261

llvm-svn: 303362
2017-05-18 17:24:10 +00:00
Tim Shen 04de70d3a7 [Atomic] Remove IsStore/IsLoad in the interface, and pass the instruction instead. NFC.
Now both emitLeadingFence and emitTrailingFence take the instruction
itself, instead of taking IsLoad/IsStore pairs.
Instruction::mayReadFromMemory and Instrucion::mayWriteToMemory are used
for determining those two booleans.

The instruction argument is also useful for later D32763, in
emitTrailingFence. For emitLeadingFence, it seems to have cleaner
interface with the proposed change.

Differential Revision: https://reviews.llvm.org/D32762

llvm-svn: 302539
2017-05-09 15:27:17 +00:00
Dehao Chen a75d0da91b Update VP prof metadata during inlining.
Summary: r298270 added profile update logic for branch_weights. This patch implements profile update logic for VP prof metadata too.

Reviewers: eraman, tejohnson, davidxl

Reviewed By: eraman

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D32773

llvm-svn: 302209
2017-05-05 00:47:34 +00:00
Adam Nemet cd847a8f30 [IR] Add AllowContract to FastMathFlags
-ffp-contract=fast does not currently work with LTO because it's passed as a
TargetOption to the backend rather than in the IR. This adds it to
FastMathFlags.

This is toward fixing PR25721

Differential Revision: https://reviews.llvm.org/D31164

llvm-svn: 298939
2017-03-28 20:11:52 +00:00
Craig Topper 1c78f4a0ff [IR] Share implementation for pairs of const and non-const methods using const_cast. NFCI
llvm-svn: 298830
2017-03-27 05:46:58 +00:00
Craig Topper 224b19d626 [IR] Make Instruction::isAssociative method inline. Add LLVM_READONLY to the static version.
llvm-svn: 298826
2017-03-26 23:23:29 +00:00
Dehao Chen 722e94061b Set the prof weight correctly for call instructions in DeadArgumentElimination.
Summary: In DeadArgumentElimination, the call instructions will be replaced. We also need to set the prof weights so that function inlining can find the correct profile.

Reviewers: eraman

Reviewed By: eraman

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D31143

llvm-svn: 298660
2017-03-23 23:26:00 +00:00
Dehao Chen e593049fb0 Updates branch_weights annotation for call instructions during inlining.
Summary: Inliner should update the branch_weights annotation to scale it to proper value.

Reviewers: davidxl, eraman

Reviewed By: eraman

Subscribers: zzheng, llvm-commits

Differential Revision: https://reviews.llvm.org/D30767

llvm-svn: 298270
2017-03-20 16:40:44 +00:00
Craig Topper f4fa291d83 [IR] Move a few static functions in Instruction class inline.
They just check for certain opcodes and opcode enums are available in Instruction.h.

llvm-svn: 298237
2017-03-20 06:40:39 +00:00
Sanjoy Das aa722ae84c [IR] Add a Instruction::dropPoisonGeneratingFlags helper
Summary:
The helper will be used in a later change.  This change itself is NFC
since the only user of this new function is its unit test.

Reviewers: majnemer, efriedma

Reviewed By: efriedma

Subscribers: efriedma, mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D30184

llvm-svn: 296035
2017-02-23 22:50:52 +00:00
Sanjay Patel a40c479fe9 fix documentation comments; NFC
llvm-svn: 283361
2016-10-05 18:51:12 +00:00
Xinliang David Li dc49140b44 [Profile] refactor meta data copying/swapping code
Differential Revision: http://reviews.llvm.org/D23619

llvm-svn: 279523
2016-08-23 15:39:03 +00:00
Duncan P. N. Exon Smith 362d120488 Scalar: Avoid dereferencing end() in IndVarSimplify
IndVarSimplify::sinkUnusedInvariants calls
BasicBlock::getFirstInsertionPt on the ExitBlock and moves instructions
before it.  This can return end(), so it's not safe to dereference.  Add
an iterator-based overload to Instruction::moveBefore to avoid the UB.

llvm-svn: 278886
2016-08-17 01:54:41 +00:00
David Majnemer 92f84ccf0f [IR] andIRFlags and copyIRFlags needs to handle GEP
We didn't consider the inbounds flag on GEPs leading to downstream users
introducing UB.

This fixes PR28562.

llvm-svn: 275532
2016-07-15 05:02:31 +00:00
David Majnemer 0f45572761 The absence of noreturn doesn't ensure mayReturn
There are two separate issues:
- LLVM doesn't consider infinite loops to be side effects: we happily
  hoist/sink above/below loops whose bounds are unknown.
- The absence of the noreturn attribute is insufficient for us to know
  if a function will definitely return.  Relying on noreturn in the
  middle-end for any property is an accident waiting to happen.

llvm-svn: 273762
2016-06-25 00:55:12 +00:00
David Majnemer d0ce8f1485 [GVN] Respect fast-math-flags on fcmps
We assumed that flags were only present on binary operators.  This is
not true, they may also be present on calls and fcmps.

llvm-svn: 267113
2016-04-22 06:37:51 +00:00
David Majnemer 9554c1339c [EarlyCSE] Take the intersection of flags on instructions
EarlyCSE had inconsistent behavior with regards to flag'd instructions:
- In some cases, it would pessimize if the available instruction had
  different flags by not performing CSE.
- In other cases, it would miscompile if it replaced an instruction
  which had no flags with an instruction which has flags.

Fix this by being more consistent with our flag handling by utilizing
andIRFlags.

llvm-svn: 267111
2016-04-22 06:37:45 +00:00
JF Bastien 5502e91c8b Check alloca's special state
Following up to a similar fix in MergeFunctions: r266022. This patch keeps both in sync, it would be nice to not have to do this. It doesn't look like there's an easy way to test this code directly at the moment: AFAICT all currect uses of isSameOperationAs are looking at instructions deep inside a function. IndVarSimplify/pr24952.ll and InstMerge/st_sink_* look at alloca inadvertently but are brittle tests.

llvm-svn: 266099
2016-04-12 18:06:55 +00:00
JF Bastien 3b6eaace62 NFC: keep comment up to date
MergeFunctions was refactored a while ago, and Instruction.cpp's comments went out of sync. The content did as well, will fix later.

llvm-svn: 266007
2016-04-11 22:30:37 +00:00
JF Bastien 800f87a871 NFC: make AtomicOrdering an enum class
Summary:
In the context of http://wg21.link/lwg2445 C++ uses the concept of
'stronger' ordering but doesn't define it properly. This should be fixed
in C++17 barring a small question that's still open.

The code currently plays fast and loose with the AtomicOrdering
enum. Using an enum class is one step towards tightening things. I later
also want to tighten related enums, such as clang's
AtomicOrderingKind (which should be shared with LLVM as a 'C++ ABI'
enum).

This change touches a few lines of code which can be improved later, I'd
like to keep it as NFC for now as it's already quite complex. I have
related changes for clang.

As a follow-up I'll add:
  bool operator<(AtomicOrdering, AtomicOrdering) = delete;
  bool operator>(AtomicOrdering, AtomicOrdering) = delete;
  bool operator<=(AtomicOrdering, AtomicOrdering) = delete;
  bool operator>=(AtomicOrdering, AtomicOrdering) = delete;
This is separate so that clang and LLVM changes don't need to be in sync.

Reviewers: jyknight, reames

Subscribers: jyknight, llvm-commits

Differential Revision: http://reviews.llvm.org/D18775

llvm-svn: 265602
2016-04-06 21:19:33 +00:00
Sanjay Patel f5c2d129d8 fix typos; NFC
llvm-svn: 256881
2016-01-06 00:18:29 +00:00
Sanjoy Das 2de4d0aa18 Teach haveSameSpecialState about operand bundles
llvm-svn: 255527
2015-12-14 19:11:35 +00:00
David Majnemer bbfc7219ef [IR] Remove terminatepad
It turns out that terminatepad gives little benefit over a cleanuppad
which calls the termination function.  This is not sufficient to
implement fully generic filters but MSVC doesn't support them which
makes terminatepad a little over-designed.

Depends on D15478.

Differential Revision: http://reviews.llvm.org/D15479

llvm-svn: 255522
2015-12-14 18:34:23 +00:00
David Majnemer 8a1c45d6e8 [IR] Reformulate LLVM's EH funclet IR
While we have successfully implemented a funclet-oriented EH scheme on
top of LLVM IR, our scheme has some notable deficiencies:
- catchendpad and cleanupendpad are necessary in the current design
  but they are difficult to explain to others, even to seasoned LLVM
  experts.
- catchendpad and cleanupendpad are optimization barriers.  They cannot
  be split and force all potentially throwing call-sites to be invokes.
  This has a noticable effect on the quality of our code generation.
- catchpad, while similar in some aspects to invoke, is fairly awkward.
  It is unsplittable, starts a funclet, and has control flow to other
  funclets.
- The nesting relationship between funclets is currently a property of
  control flow edges.  Because of this, we are forced to carefully
  analyze the flow graph to see if there might potentially exist illegal
  nesting among funclets.  While we have logic to clone funclets when
  they are illegally nested, it would be nicer if we had a
  representation which forbade them upfront.

Let's clean this up a bit by doing the following:
- Instead, make catchpad more like cleanuppad and landingpad: no control
  flow, just a bunch of simple operands;  catchpad would be splittable.
- Introduce catchswitch, a control flow instruction designed to model
  the constraints of funclet oriented EH.
- Make funclet scoping explicit by having funclet instructions consume
  the token produced by the funclet which contains them.
- Remove catchendpad and cleanupendpad.  Their presence can be inferred
  implicitly using coloring information.

N.B.  The state numbering code for the CLR has been updated but the
veracity of it's output cannot be spoken for.  An expert should take a
look to make sure the results are reasonable.

Reviewers: rnk, JosephTremoulet, andrew.w.kaylor

Differential Revision: http://reviews.llvm.org/D15139

llvm-svn: 255422
2015-12-12 05:38:55 +00:00
Sanjoy Das 411fdcd460 Add Instruction::getFunction; NFC
Will be used in a upcoming patch.

llvm-svn: 254975
2015-12-08 00:13:12 +00:00
Duncan P. N. Exon Smith 52888a6738 IR: Remove implicit iterator conversions from lib/IR, NFC
Stop converting implicitly between iterators and pointers/references in
lib/IR.  For convenience, I've added a `getIterator()` accessor to
`ilist_node` so that callers don't need to know how to spell the
iterator class (i.e., they can use `X.getIterator()` instead of
`Function::iterator(X)`).

I'll eventually disallow these implicit conversions entirely, but
there's a lot of code, so it doesn't make sense to do it all in one
patch.  One library or so at a time.

Why?  To root out cases of `getNextNode()` and `getPrevNode()` being
used in iterator logic.  The design of `ilist` makes that invalid when
the current node could be at the back of the list, but it happens to
"work" right now because of a bug where those functions never return
`nullptr` if you're using a half-node sentinel.  Before I can fix the
function, I have to remove uses of it that rely on it misbehaving.
(Maybe the function should just be deleted anyway?  But I don't want
deleting it -- potentially a huge project -- to block fixing
ilist/iplist.)

llvm-svn: 249782
2015-10-08 23:49:46 +00:00
David Majnemer 880c2cb097 [IR] Conservatively mark 'catchpad' as accessing memory
The exact semantics of 'catchpad' are really in the hands of the
personality routine so we shouldn't assume that they have no side
effects.

llvm-svn: 247322
2015-09-10 18:50:09 +00:00
Joseph Tremoulet 9ce71f76b9 [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

llvm-svn: 246751
2015-09-03 09:09:43 +00:00
Joseph Tremoulet 8220bcc570 [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

llvm-svn: 245797
2015-08-23 00:26:33 +00:00