We didn't have logic to correctly handle CFGs where there was more than
one EH-pad successor (these are novel with WinEH).
There were situations where a register was live in one exceptional
successor but not another but the code as written would only consider
the first exceptional successor it found.
This resulted in split points which were insufficiently early if an
invoke was present.
This fixes PR27501.
N.B. This removes getLandingPadSuccessor.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267412 91177308-0d34-0410-b5e6-96231b3b80d8
splitting edges.
MachineBasicBlock::SplitCriticalEdges will crash if a nullptr would have
been passed for the Pass argument. Do not allow that by turning this
argument into a reference.
The alternative would have been to make the Pass a truly optional
argument, but although this is easy to do, I was afraid users using it
like this would not be aware the livness information, dominator tree and
such would silently be broken.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267052 91177308-0d34-0410-b5e6-96231b3b80d8
Introduce canSplitCriticalEdge, so that clients can now query whether or
not a critical edge can be split without actually needing to split it.
This may be useful when gathering information for cost models for
instance.
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Take MachineInstr by reference instead of by pointer in SlotIndexes and
the SlotIndex wrappers in LiveIntervals. The MachineInstrs here are
never null, so this cleans up the API a bit. It also incidentally
removes a few implicit conversions from MachineInstrBundleIterator to
MachineInstr* (see PR26753).
At a couple of call sites it was convenient to convert to a range-based
for loop over MachineBasicBlock::instr_begin/instr_end, so I added
MachineBasicBlock::instrs.
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This is a little embarrassing.
When I reverted r261504 (getIterator() => getInstrIterator()) in
r261567, I did a `git grep` to see if there were new calls to
`getInstrIterator()` that I needed to migrate. There were 10-20 hits,
and I blindly did a `sed ...` before calling `ninja check`.
However, these were `MachineInstrBundleIterator::getInstrIterator()`,
which predated r261567. Perhaps coincidentally, these had an identical
name and return type.
This commit undoes my careless sed and restores
`MachineBasicBlock::iterator::getInstrIterator()`.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261577 91177308-0d34-0410-b5e6-96231b3b80d8
Split MachineBasicBlock::bundle_iterator into a separate file, and
rename the class to MachineBundleIterator.
This is a precursor to adding a `MachineInstr::getBundleIterator()`
accessor, which will eventually let us delete the final call to
getNodePtrUnchecked(), and then remove the UB from ilist_iterator.
As a drive-by, I removed an unnecessary second template parameter.
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This patch adds some missing calls to MBB::normalizeSuccProbs() in several
locations where it should be called. Those places are found by checking if the
sum of successors' probabilities is approximate one in MachineBlockPlacement
pass with some instrumented code (not in this patch).
Differential revision: http://reviews.llvm.org/D15259
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computeRegisterLiveness() was broken in that it reported dead for a
register even if a subregister was alive. I assume this was because the
results of analayzePhysRegs() are hard to understand with respect to
subregisters.
This commit: Changes the results of analyzePhysRegs (=struct
PhysRegInfo) to be clearly understandable, also renames the fields to
avoid silent breakage of third-party code (and improve the grammar).
Fix all (two) users of computeRegisterLiveness() in llvm: By reenabling
it and removing workarounds for the bug.
This fixes http://llvm.org/PR24535 and http://llvm.org/PR25033
Differential Revision: http://reviews.llvm.org/D15320
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(This is the second attempt to submit this patch. The first caused two assertion
failures and was reverted. See https://llvm.org/bugs/show_bug.cgi?id=25687)
The patch in http://reviews.llvm.org/D13745 is broken into four parts:
1. New interfaces without functional changes (http://reviews.llvm.org/D13908).
2. Use new interfaces in SelectionDAG, while in other passes treat probabilities
as weights (http://reviews.llvm.org/D14361).
3. Use new interfaces in all other passes.
4. Remove old interfaces.
This patch is 3+4 above. In this patch, MBB won't provide weight-based
interfaces any more, which are totally replaced by probability-based ones.
The interface addSuccessor() is redesigned so that the default probability is
unknown. We allow unknown probabilities but don't allow using it together
with known probabilities in successor list. That is to say, we either have a
list of successors with all known probabilities, or all unknown
probabilities. In the latter case, we assume each successor has 1/N
probability where N is the number of successors. An assertion checks if the
user is attempting to add a successor with the disallowed mixed use as stated
above. This can help us catch many misuses.
All uses of weight-based interfaces are now updated to use probability-based
ones.
Differential revision: http://reviews.llvm.org/D14973
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254377 91177308-0d34-0410-b5e6-96231b3b80d8
and the follow-up r254356: "Fix a bug in MachineBlockPlacement that may cause assertion failure during BranchProbability construction."
Asserts were firing in Chromium builds. See PR25687.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254366 91177308-0d34-0410-b5e6-96231b3b80d8
The patch in http://reviews.llvm.org/D13745 is broken into four parts:
1. New interfaces without functional changes (http://reviews.llvm.org/D13908).
2. Use new interfaces in SelectionDAG, while in other passes treat probabilities
as weights (http://reviews.llvm.org/D14361).
3. Use new interfaces in all other passes.
4. Remove old interfaces.
This patch is 3+4 above. In this patch, MBB won't provide weight-based
interfaces any more, which are totally replaced by probability-based ones.
The interface addSuccessor() is redesigned so that the default probability is
unknown. We allow unknown probabilities but don't allow using it together
with known probabilities in successor list. That is to say, we either have a
list of successors with all known probabilities, or all unknown
probabilities. In the latter case, we assume each successor has 1/N
probability where N is the number of successors. An assertion checks if the
user is attempting to add a successor with the disallowed mixed use as stated
above. This can help us catch many misuses.
All uses of weight-based interfaces are now updated to use probability-based
ones.
Differential revision: http://reviews.llvm.org/D14973
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@254348 91177308-0d34-0410-b5e6-96231b3b80d8
Re-implement `ilist_node::getNextNode()` and `getPrevNode()` without
relying on the sentinel having a "next" pointer. Instead, get access to
the owning list and compare against the `begin()` and `end()` iterators.
This only works when the node *can* get access to the owning list. The
new support is in `ilist_node_with_parent<>`, and any class `Ty`
inheriting from `ilist_node<NodeTy>` that wants `getNextNode()` and/or
`getPrevNode()` should inherit from
`ilist_node_with_parent<NodeTy, ParentTy>` instead. The requirements:
- `NodeTy` must have a `getParent()` function that returns the parent.
- `ParentTy` must have a `getSublistAccess()` static that, given a(n
ignored) `NodeTy*` (to determine which list), returns a member field
pointer to the appropriate `ilist<>`.
This isn't the cleanest way to get access to the owning list, but it
leverages the API already used in the IR hierarchy (see, e.g.,
`Instruction::getSublistAccess()`).
If anyone feels like ripping out the calls to `getNextNode()` and
`getPrevNode()` and replacing with direct iterator logic, they can also
remove the access function, etc., but as an incremental step, I'm
maintaining the API where it's currently used in tree.
If these requirements are *not* met, call sites with access to the ilist
can call `iplist<NodeTy>::getNextNode(NodeTy*)` directly, as in
ilistTest.cpp.
Why rewrite this?
The old code was broken, calling `getNext()` on a sentinel that possibly
didn't have a "next" pointer at all! The new code avoids that
particular flavour of UB (see the commit message for r252538 for more
details about the "lucky" memory layout that made this function so
interesting).
There's still some UB here: the end iterator gets downcast to `NodeTy*`,
even when it's a sentinel (which is typically
`ilist_half_node<NodeTy*>`). I'll tackle that in follow-up commits.
See this llvm-dev thread for more details:
http://lists.llvm.org/pipermail/llvm-dev/2015-October/091115.html
What's the danger?
There might be some code that relies on `getNextNode()` or
`getPrevNode()` *never* returning `nullptr` -- i.e., that relies on them
being broken when the sentinel is an `ilist_half_node<NodeTy>`. I tried
to root out those cases with the audits I did leading up to r252380, but
it's possible I missed one or two. I hope not.
(If (1) you have out-of-tree code, (2) you've reverted r252380
temporarily, and (3) you get some weird crashes with this commit, then I
recommend un-reverting r252380 and auditing the compile errors looking
for "strange" implicit conversions.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252694 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
In this implementation, LiveIntervalAnalysis invents a few register
masks on basic block boundaries that preserve no registers. The nice
thing about this is that it prevents the prologue inserter from thinking
it needs to spill all XMM CSRs, because it doesn't see any explicit
physreg defs in the MI.
Reviewers: MatzeB, qcolombet, JosephTremoulet, majnemer
Subscribers: MatzeB, llvm-commits
Differential Revision: http://reviews.llvm.org/D14407
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When optimization is disabled, edge weights that are stored in MBB won't be used so that we don't have to store them. Currently, this is done by adding successors with default weight 0, and if all successors have default weights, the weight list will be empty. But that the weight list is empty doesn't mean disabled optimization (as is stated several times in MachineBasicBlock.cpp): it may also mean all successors just have default weights.
We should discourage using default weights when adding successors, because it is very easy for users to forget update the correct edge weights instead of using default ones (one exception is that the MBB only has one successor). In order to detect such usages, it is better to differentiate using default weights from the case when optimizations is disabled.
In this patch, a new interface addSuccessorWithoutWeight(MBB*) is created for when optimization is disabled. In this case, MBB will try to maintain an empty weight list, but it cannot guarantee this as for many uses of addSuccessor() whether optimization is disabled or not is not checked. But it can guarantee that if optimization is enabled, then the weight list always has the same size of the successor list.
Differential revision: http://reviews.llvm.org/D13963
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251429 91177308-0d34-0410-b5e6-96231b3b80d8
Start removing implicit conversions to/from list iterators in CodeGen,
ala r249782 for IR. A lot more to go after this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249851 91177308-0d34-0410-b5e6-96231b3b80d8
Nothing inherits from `MachineBasicBlock`, so this should have no real
functionality change. Just makes the code easier to understand.
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Summary:
Funclets have been turned into functions by the time they hit the object
file. Make sure that they have decent names for the symbol table and
CFI directives explaining how to reason about their prologues.
Differential Revision: http://reviews.llvm.org/D13261
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getLandingPadSuccessor assumes that each invoke can have at most one EH
pad successor, but WinEH invokes can have more than one. Two out of
three callers of getLandingPadSuccessor don't use the returned
landingpad, so we can make them use this simple predicate instead.
Eventually we'll have to circle back and fix SplitKit.cpp so that
register allocation works. Baby steps.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247904 91177308-0d34-0410-b5e6-96231b3b80d8
With subregister liveness enabled we can detect the case where only
parts of a register are live in, this is expressed as a 32bit lanemask.
The current code only keeps registers in the live-in list and therefore
enumerated all subregisters affected by the lanemask. This turned out to
be too conservative as the subregister may also cover additional parts
of the lanemask which are not live. Expressing a given lanemask by
enumerating a minimum set of subregisters is computationally expensive
so the best solution is to simply change the live-in list to store the
lanemasks as well. This will reduce memory usage for targets using
subregister liveness and slightly increase it for other targets
Differential Revision: http://reviews.llvm.org/D12442
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We can now run 32-bit programs with empty catch bodies. The next step
is to change PEI so that we get funclet prologues and epilogues.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@246235 91177308-0d34-0410-b5e6-96231b3b80d8
This is friendlier to the readers as it makes it clear that the API is
not meant for vregs but just for physregs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245977 91177308-0d34-0410-b5e6-96231b3b80d8
This commit modifies the way the machine basic blocks are serialized - now the
machine basic blocks are serialized using a custom syntax instead of relying on
YAML primitives. Instead of using YAML mappings to represent the individual
machine basic blocks in a machine function's body, the new syntax uses a single
YAML block scalar which contains all of the machine basic blocks and
instructions for that function.
This is an example of a function's body that uses the old syntax:
body:
- id: 0
name: entry
instructions:
- '%eax = MOV32r0 implicit-def %eflags'
- 'RETQ %eax'
...
The same body is now written like this:
body: |
bb.0.entry:
%eax = MOV32r0 implicit-def %eflags
RETQ %eax
...
This syntax change is motivated by the fact that the bundled machine
instructions didn't map that well to the old syntax which was using a single
YAML sequence to store all of the machine instructions in a block. The bundled
machine instructions internally use flags like BundledPred and BundledSucc to
determine the bundles, and serializing them as MI flags using the old syntax
would have had a negative impact on the readability and the ease of editing
for MIR files. The new syntax allows me to serialize the bundled machine
instructions using a block construct without relying on the internal flags,
for example:
BUNDLE implicit-def dead %itstate, implicit-def %s1 ... {
t2IT 1, 24, implicit-def %itstate
%s1 = VMOVS killed %s0, 1, killed %cpsr, implicit killed %itstate
}
This commit also converts the MIR testcases to the new syntax. I developed
a script that can convert from the old syntax to the new one. I will post the
script on the llvm-commits mailing list in the thread for this commit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244982 91177308-0d34-0410-b5e6-96231b3b80d8
1. Create a utility function normalizeEdgeWeights() in MachineBranchProbabilityInfo that normalizes a list of edge weights so that the sum of then can fit in uint32_t.
2. Provide an interface in MachineBasicBlock to normalize its successors' weights.
3. Add a flag in MachineBasicBlock that tracks whether its successors' weights are normalized.
4. Provide an overload of getSumForBlock that accepts a non-const pointer to a MBB so that it can force normalizing this MBB's successors' weights.
5. Update several uses of getSumForBlock() by eliminating the once needed weight scale.
Differential Revision: http://reviews.llvm.org/D11442
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244154 91177308-0d34-0410-b5e6-96231b3b80d8
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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240842 91177308-0d34-0410-b5e6-96231b3b80d8
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!
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- Clean documentation comment
- Change the API to accept an iterator so you can actually pass
MachineBasicBlock::end() now.
- Add more "const".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238288 91177308-0d34-0410-b5e6-96231b3b80d8
This change to VirtRegRewriter::addMBBLiveIns adds live-in registers for each
MachineBasicBlock's LiveIns set without isLiveIn checks as they are being added
because doing so is expensive. After all live-in registers are added, the LiveIn
vectors are sorted and uniqued.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238008 91177308-0d34-0410-b5e6-96231b3b80d8
When "MBB->Insert(It, ...)" is called, we want It to be pointing inside the
correct basic block. No actual failures at the moment, but it's caused problems
before.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221953 91177308-0d34-0410-b5e6-96231b3b80d8
This makes front/back symmetric with begin/end, avoiding some confusion.
Added instr_front/instr_back for the old behavior, corresponding to
instr_begin/instr_end. Audited all three in-tree users of back(), all
of them look like they don't want to look inside bundles.
Fixes an assertion (PR19815) when generating debug info on mips, where a
delay slot was bundled at the end of a branch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209580 91177308-0d34-0410-b5e6-96231b3b80d8
