The purpose of this utility is to make it easier for optimizations to
insert replacement dbg.values for instructions they are deleting. This
is useful in situations where salvageDebugInfo is inapplicable, say,
because the new dbg.value cannot refer to an operand of the dying value.
The utility is called insertReplacementDbgValues.
It assumes that the instruction 'From' is going to be deleted, and
inserts replacement dbg.values for each debug user of 'From'. The
newly-inserted dbg.values refer to 'To' instead of 'From'. Each
replacement dbg.value has the same location and variable as the debug
user it replaces, has a DIExpression determined by the result of
'RewriteExpr' applied to an old debug user of 'From', and is placed
before 'InsertBefore'.
This should simplify future patches, like D48331.
llvm-svn: 335144
This is a fixup for r334830 causing problems in polly-aosp buildbot.
Focus in r334830 was to fix a problem seen with
ConvertDebugDeclareToDebugValue involving store instructions.
It also added some asserts to find out of similar problems
existed for the ConvertDebugDeclareToDebugValue functions
involving load and phi instructions. One of those asserts seems
to blow in the polly-aosp buildbot, so I'll revert the asserts
while debugging.
llvm-svn: 335031
This is r334704 (which was reverted in r334732) with a fix for
types like x86_fp80. We need to use getTypeAllocSizeInBits and
not getTypeStoreSizeInBits to avoid dropping debug info for
such types.
Original commit msg:
> Summary:
> Do not convert a DbgDeclare to DbgValue if the store
> instruction only refer to a fragment of the variable
> described by the DbgDeclare.
>
> Problem was seen when for example having an alloca for an
> array or struct, and there were stores to individual elements.
> In the past we inserted a DbgValue intrinsics for each store,
> just as if the store wrote the whole variable.
>
> When handling store instructions we insert a DbgValue that
> indicates that the variable is "undefined", as we do not know
> which part of the variable that is updated by the store.
>
> When ConvertDebugDeclareToDebugValue is used with a load/phi
> instruction we assert that the referenced value is large enough
> to cover the whole variable. Afaict this should be true for all
> scenarios where those methods are used on trunk. If the assert
> blows in the future I guess we could simply skip to insert a
> dbg.value instruction.
>
> In the future I think we should examine which part of the variable
> that is accessed, and add a DbgValue instrinsic with an appropriate
> DW_OP_LLVM_fragment expression.
>
> Reviewers: dblaikie, aprantl, rnk
>
> Reviewed By: aprantl
>
> Subscribers: JDevlieghere, llvm-commits
>
> Tags: #debug-info
>
> Differential Revision: https://reviews.llvm.org/D48024
llvm-svn: 334830
Summary:
Do not convert a DbgDeclare to DbgValue if the store
instruction only refer to a fragment of the variable
described by the DbgDeclare.
Problem was seen when for example having an alloca for an
array or struct, and there were stores to individual elements.
In the past we inserted a DbgValue intrinsics for each store,
just as if the store wrote the whole variable.
When handling store instructions we insert a DbgValue that
indicates that the variable is "undefined", as we do not know
which part of the variable that is updated by the store.
When ConvertDebugDeclareToDebugValue is used with a load/phi
instruction we assert that the referenced value is large enough
to cover the whole variable. Afaict this should be true for all
scenarios where those methods are used on trunk. If the assert
blows in the future I guess we could simply skip to insert a
dbg.value instruction.
In the future I think we should examine which part of the variable
that is accessed, and add a DbgValue instrinsic with an appropriate
DW_OP_LLVM_fragment expression.
Reviewers: dblaikie, aprantl, rnk
Reviewed By: aprantl
Subscribers: JDevlieghere, llvm-commits
Tags: #debug-info
Differential Revision: https://reviews.llvm.org/D48024
llvm-svn: 334704
Review feedback from r328165. Split out just the one function from the
file that's used by Analysis. (As chandlerc pointed out, the original
change only moved the header and not the implementation anyway - which
was fine for the one function that was used (since it's a
template/inlined in the header) but not in general)
llvm-svn: 333954
be both simpler and substantially more efficient.
Rather than use a hand-rolled iteration technique that isn't quite the
same as RPO, use the pre-built RPO loop body traversal utility.
Once visiting the loop body in RPO, we can assert that we visit defs
before uses reliably. When this is the case, the only need to iterate is
when simplifying a def that is used by a PHI node along a back-edge.
With this patch, the first pass over the loop body is just a complete
simplification of every instruction across the loop body. When we
encounter a use of a simplified instruction that stems from a PHI node
in the loop body that has already been visited (due to some cyclic CFG,
potentially the loop itself, or a nested loop, or unstructured control
flow), we recall that specific PHI node for the second iteration.
Nothing else needs to be preserved from iteration to iteration.
On the second and later iterations, only instructions known to have
simplified inputs are considered, each time starting from a set of PHIs
that had simplified inputs along the backedges.
Dead instructions are collected along the way, but deleted in a batch at
the end of each iteration making the iterations themselves substantially
simpler. This uses a new batch API for recursively deleting dead
instructions.
This alsa changes the routine to visit subloops. Because simplification
is fundamentally transitive, we may need to visit the entire loop body,
including subloops, to handle knock-on simplification.
I've added a basic test file that helps demonstrate that all of these
changes work. It includes both straight-forward loops with
simplifications as well as interesting PHI-structures, CFG-structures,
and a nested loop case.
Differential Revision: https://reviews.llvm.org/D47407
llvm-svn: 333461
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.
In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.
Differential Revision: https://reviews.llvm.org/D43624
llvm-svn: 332240
This commit adds a wrapper for std::distance() which works with ranges.
As it would be a common case to write `distance(predecessors(BB))`, this
also introduces `pred_size()` and `succ_size()` helpers to make that
easier to write.
Differential Revision: https://reviews.llvm.org/D46668
llvm-svn: 332057
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is
!DILabel(scope: !1, name: "foo", file: !2, line: 3)
We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is
llvm.dbg.label(metadata !1)
It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.
We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.
Differential Revision: https://reviews.llvm.org/D45024
Patch by Hsiangkai Wang.
llvm-svn: 331841
Inspired by r331508, I did a grep and found these.
Mostly just change from dyn_cast to cast. Some cases also showed a dyn_cast result being converted to bool, so those I changed to isa.
llvm-svn: 331577
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
llvm-svn: 331272
This patch adds support for fragment expressions
TryToShrinkGlobalToBoolean() which were previously just dropped.
Thanks to Reid Kleckner for providing me a reproducer!
llvm-svn: 331086
Remove #include of Transforms/Scalar.h from Transform/Utils to fix layering.
Transforms depends on Transforms/Utils, not the other way around. So
remove the header and the "createStripGCRelocatesPass" function
declaration (& definition) that is unused and motivated this dependency.
Move Transforms/Utils/Local.h into Analysis because it's used by
Analysis/MemoryBuiltins.cpp.
llvm-svn: 328165
There is no point in lowering a dbg.declare describing an alloca that
has volatile loads or stores as users, since the alloca cannot be
elided. Lowering the dbg.declare will result in larger debug info that
may also have worse coverage than just describing the alloca.
rdar://problem/34496278
llvm-svn: 327092
In stage2 -O3 builds of llc, this results in small but measurable
increases in the number of variables with locations, and in the number
of unique source variables overall.
(According to llvm-dwarfdump --statistics, there are 123 additional
variables with locations, which is just a 0.006% improvement).
The size of the .debug_loc section of the llc dsym increases by 0.004%.
llvm-svn: 326629
In stage2 -O3 builds of llc, this results in a 0.3% increase in the
number of variables with locations, and a 0.2% increase in the number of
unique source variables overall.
The size of the .debug_loc section of the llc dsym increases by 0.5%.
llvm-svn: 326621
Summary:
This patch is an enhancement to propagate dbg.value information when Phis are created on behalf of LCSSA.
I noticed a case where a value carried across a loop was reported as <optimized out>.
Specifically this case:
```
int bar(int x, int y) {
return x + y;
}
int foo(int size) {
int val = 0;
for (int i = 0; i < size; ++i) {
val = bar(val, i); // Both val and i are correct
}
return val; // <optimized out>
}
```
In the above case, after all of the interesting computation completes our value
is reported as "optimized out." This change will add a dbg.value to correct this.
This patch also moves the dbg.value insertion routine from LoopRotation.cpp
into Local.cpp, so that we can share it in both places (LoopRotation and LCSSA).
Reviewers: mzolotukhin, aprantl, vsk, davide
Reviewed By: aprantl, vsk
Subscribers: dberlin, llvm-commits
Differential Revision: https://reviews.llvm.org/D42551
llvm-svn: 325926
According to the current coverage report salvageDebugInfo() is called
5.12 million times during testing and almost always returns early.
The early return depends on LocalAsMetadata::getIfExists returning null,
which involves a DenseMap lookup in an LLVMContextImpl. We can probably
speed this up by simply checking the IsUsedByMD bit in Value.
llvm-svn: 325738
Preserve debug info from a dead 'and' instruction with a constant.
Patch by Djordje Todorovic.
Differential Revision: https://reviews.llvm.org/D43163
llvm-svn: 325119
Making a width of GEP Index, which is used for address calculation, to be one of the pointer properties in the Data Layout.
p[address space]:size:memory_size:alignment:pref_alignment:index_size_in_bits.
The index size parameter is optional, if not specified, it is equal to the pointer size.
Till now, the InstCombiner normalized GEPs and extended the Index operand to the pointer width.
It works fine if you can convert pointer to integer for address calculation and all registered targets do this.
But some ISAs have very restricted instruction set for the pointer calculation. During discussions were desided to retrieve information for GEP index from the Data Layout.
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120416.html
I added an interface to the Data Layout and I changed the InstCombiner and some other passes to take the Index width into account.
This change does not affect any in-tree target. I added tests to cover data layouts with explicitly specified index size.
Differential Revision: https://reviews.llvm.org/D42123
llvm-svn: 325102
We already try to salvage debug values from no-op bitcasts and inttoptr
instructions: we should handle ptrtoint instructions as well.
This saves an additional 24,444 debug values in a stage2 build of clang,
and (according to llvm-dwarfdump --statistics) provides an additional
289 unique source variables.
llvm-svn: 324982
Here are the number of additional debug values salvaged in a stage2
build of clang:
63 SALVAGE: MUL
1250 SALVAGE: SDIV
(No values were salvaged from `srem` instructions in this experiment,
but it's a simple case to handle so we might as well.)
llvm-svn: 324976
Here are the number of additional debug values salvaged in a stage2
build of clang:
1912 SALVAGE: ASHR
405 SALVAGE: LSHR
249 SALVAGE: SHL
llvm-svn: 324975
Extend salvageDebugInfo to preserve the debug info from a dead 'or'
with a constant.
Patch by Ismail Badawi!
Differential Revision: https://reviews.llvm.org/D43129
llvm-svn: 324764
Inserting a dbg.value instruction at the start of a basic block with a
landingpad instruction triggers a verifier failure. We should be OK if
we insert the instruction a bit later.
Speculative fix for the bot failure described here:
https://reviews.llvm.org/D42551
llvm-svn: 323482
Summary:
See D37528 for a previous (non-deferred) version of this
patch and its description.
Preserves dominance in a deferred manner using a new class
DeferredDominance. This reduces the performance impact of
updating the DominatorTree at every edge insertion and
deletion. A user may call DDT->flush() within JumpThreading
for an up-to-date DT. This patch currently has one flush()
at the end of runImpl() to ensure DT is preserved across
the pass.
LVI is also preserved to help subsequent passes such as
CorrelatedValuePropagation. LVI is simpler to maintain and
is done immediately (not deferred). The code to perform the
preversation was minimally altered and simply marked as
preserved for the PassManager to be informed.
This extends the analysis available to JumpThreading for
future enhancements such as threading across loop headers.
Reviewers: dberlin, kuhar, sebpop
Reviewed By: kuhar, sebpop
Subscribers: mgorny, dmgreen, kuba, rnk, rsmith, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D40146
llvm-svn: 322401
Having a single call to findDbgUsers() allows salvageDebugInfo() to
return earlier.
Differential Revision: https://reviews.llvm.org/D41787
llvm-svn: 321915
Summary:
See D37528 for a previous (non-deferred) version of this
patch and its description.
Preserves dominance in a deferred manner using a new class
DeferredDominance. This reduces the performance impact of
updating the DominatorTree at every edge insertion and
deletion. A user may call DDT->flush() within JumpThreading
for an up-to-date DT. This patch currently has one flush()
at the end of runImpl() to ensure DT is preserved across
the pass.
LVI is also preserved to help subsequent passes such as
CorrelatedValuePropagation. LVI is simpler to maintain and
is done immediately (not deferred). The code to perfom the
preversation was minimally altered and was simply marked
as preserved for the PassManager to be informed.
This extends the analysis available to JumpThreading for
future enhancements. One example is loop boundary threading.
Reviewers: dberlin, kuhar, sebpop
Reviewed By: kuhar, sebpop
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D40146
llvm-svn: 321825
Summary:
See D37528 for a previous (non-deferred) version of this
patch and its description.
Preserves dominance in a deferred manner using a new class
DeferredDominance. This reduces the performance impact of
updating the DominatorTree at every edge insertion and
deletion. A user may call DDT->flush() within JumpThreading
for an up-to-date DT. This patch currently has one flush()
at the end of runImpl() to ensure DT is preserved across
the pass.
LVI is also preserved to help subsequent passes such as
CorrelatedValuePropagation. LVI is simpler to maintain and
is done immediately (not deferred). The code to perfom the
preversation was minimally altered and was simply marked
as preserved for the PassManager to be informed.
This extends the analysis available to JumpThreading for
future enhancements. One example is loop boundary threading.
Reviewers: dberlin, kuhar, sebpop
Reviewed By: kuhar, sebpop
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D40146
llvm-svn: 320612
Revert "[SROA] Propagate !range metadata when moving loads."
Revert "[Mem2Reg] Clang-format unformatted parts of this file. NFCI."
Davide says they broke a bot.
llvm-svn: 319131
This tries to propagate !range metadata to a pre-existing load
when a load is optimized out. This is done instead of adding an
assume because converting loads to and from assumes creates a
lot of IR.
Patch by Ariel Ben-Yehuda.
Differential Revision: https://reviews.llvm.org/D37216
llvm-svn: 319096
Summary:
Instcombine (and probably other passes) sometimes want to change the
type of an alloca. To do this, they generally create a new alloca with
the desired type, create a bitcast to make the new pointer type match
the old pointer type, replace all uses with the cast, and then simplify
the casts. We already knew how to salvage dbg.value instructions when
removing casts, but we can extend it to cover dbg.addr and dbg.declare.
Fixes a debug info quality issue uncovered in Chromium in
http://crbug.com/784609
Reviewers: aprantl, vsk
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D40042
llvm-svn: 318203
This preserves the debug info for the cast operation in the original location.
rdar://problem/33460652
Reapplied r317340 with the test moved into an ARM-specific directory.
llvm-svn: 317375
Summary: For some irreducible CFG the domtree nodes might be dead, do not update domtree for dead nodes.
Reviewers: kuhar, dberlin, hfinkel
Reviewed By: kuhar
Subscribers: llvm-commits, mcrosier
Differential Revision: https://reviews.llvm.org/D38960
llvm-svn: 316582
JumpThreading now preserves dominance and lazy value information across the
entire pass. The pass manager is also informed of this preservation with
the goal of DT and LVI being recalculated fewer times overall during
compilation.
This change prepares JumpThreading for enhanced opportunities; particularly
those across loop boundaries.
Patch by: Brian Rzycki <b.rzycki@samsung.com>,
Sebastian Pop <s.pop@samsung.com>
Differential revision: https://reviews.llvm.org/D37528
llvm-svn: 314435
The fix is to avoid invalidating our insertion point in
replaceDbgDeclare:
Builder.insertDeclare(NewAddress, DIVar, DIExpr, Loc, InsertBefore);
+ if (DII == InsertBefore)
+ InsertBefore = &*std::next(InsertBefore->getIterator());
DII->eraseFromParent();
I had to write a unit tests for this instead of a lit test because the
use list order matters in order to trigger the bug.
The reduced C test case for this was:
void useit(int*);
static inline void inlineme() {
int x[2];
useit(x);
}
void f() {
inlineme();
inlineme();
}
llvm-svn: 313905
.. as well as the two subsequent changes r313826 and r313875.
This leads to segfaults in combination with ASAN. Will forward repro
instructions to the original author (rnk).
llvm-svn: 313876
Summary:
This implements the design discussed on llvm-dev for better tracking of
variables that live in memory through optimizations:
http://lists.llvm.org/pipermail/llvm-dev/2017-September/117222.html
This is tracked as PR34136
llvm.dbg.addr is intended to be produced and used in almost precisely
the same way as llvm.dbg.declare is today, with the exception that it is
control-dependent. That means that dbg.addr should always have a
position in the instruction stream, and it will allow passes that
optimize memory operations on local variables to insert llvm.dbg.value
calls to reflect deleted stores. See SourceLevelDebugging.rst for more
details.
The main drawback to generating DBG_VALUE machine instrs is that they
usually cause LLVM to emit a location list for DW_AT_location. The next
step will be to teach DwarfDebug.cpp how to recognize more DBG_VALUE
ranges as not needing a location list, and possibly start setting
DW_AT_start_offset for variables whose lifetimes begin mid-scope.
Reviewers: aprantl, dblaikie, probinson
Subscribers: eraman, hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D37768
llvm-svn: 313825
There is no situation where this rarely-used argument cannot be
substituted with a DIExpression and removing it allows us to simplify
the DWARF backend. Note that this patch does not yet remove any of
the newly dead code.
rdar://problem/33580047
Differential Revision: https://reviews.llvm.org/D35951
llvm-svn: 309426
Summary:
It is possible for some passes to materialize a call to a libcall (ex: ldexp, exp2, etc),
but these passes will not mark the call as a gc-leaf-function. All libcalls are
actually gc-leaf-functions, so we change llvm::callsGCLeafFunction() to tell us that
available libcalls are equivalent to gc-leaf-function calls.
Reviewers: sanjoy, anna, reames
Reviewed By: anna
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D35840
llvm-svn: 309291
Summary:
As metioned in https://reviews.llvm.org/D34576, checkings in
`collectConstantCandidates` can be replaced by using
`llvm::canReplaceOperandWithVariable`.
The only special case is that `collectConstantCandidates` return false for
all `IntrinsicInst` but it is safe for us to collect constant candidates from
`IntrinsicInst`.
Reviewers: pirama, efriedma, srhines
Reviewed By: efriedma
Subscribers: llvm-commits, javed.absar
Differential Revision: https://reviews.llvm.org/D34921
llvm-svn: 307587
Summary:
`Instruction::Switch`: only first operand can be set to a non-constant value.
`Instruction::InsertValue` both the first and the second operand can be set to a non-constant value.
`Instruction::Alloca` return true for non-static allocation.
Reviewers: efriedma
Reviewed By: efriedma
Subscribers: srhines, pirama, llvm-commits
Differential Revision: https://reviews.llvm.org/D34905
llvm-svn: 307294
metadata out of InstCombine and into helpers.
NFC, this just exposes the logic used by InstCombine when propagating
metadata from one load instruction to another. The plan is to use this
in SROA to address PR32902.
If anyone has better ideas about how to factor this or name variables,
I'm all ears, but this seemed like a pretty good start and lets us make
progress on the PR.
This is based on a patch by Ariel Ben-Yehuda (D34285).
llvm-svn: 306267
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
This patch provides an initial prototype for a pass that sinks instructions based on GVN information, similar to GVNHoist. It is not yet ready for commiting but I've uploaded it to gather some initial thoughts.
This pass attempts to sink instructions into successors, reducing static
instruction count and enabling if-conversion.
We use a variant of global value numbering to decide what can be sunk.
Consider:
[ %a1 = add i32 %b, 1 ] [ %c1 = add i32 %d, 1 ]
[ %a2 = xor i32 %a1, 1 ] [ %c2 = xor i32 %c1, 1 ]
\ /
[ %e = phi i32 %a2, %c2 ]
[ add i32 %e, 4 ]
GVN would number %a1 and %c1 differently because they compute different
results - the VN of an instruction is a function of its opcode and the
transitive closure of its operands. This is the key property for hoisting
and CSE.
What we want when sinking however is for a numbering that is a function of
the *uses* of an instruction, which allows us to answer the question "if I
replace %a1 with %c1, will it contribute in an equivalent way to all
successive instructions?". The (new) PostValueTable class in GVN provides this
mapping.
This pass has some shown really impressive improvements especially for codesize already on internal benchmarks, so I have high hopes it can replace all the sinking logic in SimplifyCFG.
Differential revision: https://reviews.llvm.org/D24805
llvm-svn: 303850
This continues the changes started when computeSignBit was replaced with this new version of computeKnowBits.
Differential Revision: https://reviews.llvm.org/D33431
llvm-svn: 303773
This patch builds over https://reviews.llvm.org/rL303349 and replaces
the use of the condition only if it is safe to do so.
We should not blindly RAUW the condition if experimental.guard or assume
is a use of that
condition. This is because LVI may have used the guard/assume to
identify the
value of the condition, and RUAWing will fold the guard/assume and uses
before the guards/assumes.
Reviewers: sanjoy, reames, trentxintong, mkazantsev
Reviewed by: sanjoy, reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D33257
llvm-svn: 303633
There's no need (& a bit incorrect) to mask off the high bits of the
register reference when describing a simple bool value.
Reviewers: aprantl
Differential Revision: https://reviews.llvm.org/D31062
llvm-svn: 303117
This patch adds min/max population count, leading/trailing zero/one bit counting methods.
The min methods return answers based on bits that are known without considering unknown bits. The max methods give answers taking into account the largest count that unknown bits could give.
Differential Revision: https://reviews.llvm.org/D32931
llvm-svn: 302925
Summary:
Since I will post patch with some changes to
replaceDominatedUsesWith, it would be good to avoid
duplicating code again.
Reviewers: davide, dberlin
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32798
llvm-svn: 302575
This is a follow up to the fix in r298360 to improve the handling of debug
values when redundant LEAs are removed. The fix in r298360 effectively
discarded the debug values. This patch now attempts to preserve the debug
values by using the DWARF DW_OP_stack_value operation via prependDIExpr.
Moved functions appendOffset and prependDIExpr from Local.cpp to
DebugInfoMetadata.cpp and made them available as static member functions of
DIExpression.
Differential Revision: https://reviews.llvm.org/D31604
llvm-svn: 301630
This patch introduces a new KnownBits struct that wraps the two APInt used by computeKnownBits. This allows us to treat them as more of a unit.
Initially I've just altered the signatures of computeKnownBits and InstCombine's simplifyDemandedBits to pass a KnownBits reference instead of two separate APInt references. I'll do similar to the SelectionDAG version of computeKnownBits/simplifyDemandedBits as a separate patch.
I've added a constructor that allows initializing both APInts to the same bit width with a starting value of 0. This reduces the repeated pattern of initializing both APInts. Once place default constructed the APInts so I added a default constructor for those cases.
Going forward I would like to add more methods that will work on the pairs. For example trunc, zext, and sext occur on both APInts together in several places. We should probably add a clear method that can be used to clear both pieces. Maybe a method to check for conflicting information. A method to return (Zero|One) so we don't write it out everywhere. Maybe a method for (Zero|One).isAllOnesValue() to determine if all bits are known. I'm sure there are many other methods we can come up with.
Differential Revision: https://reviews.llvm.org/D32376
llvm-svn: 301432
Commits were:
"Use WeakVH instead of WeakTrackingVH in AliasSetTracker's UnkownInsts"
"Add a new WeakVH value handle; NFC"
"Rename WeakVH to WeakTrackingVH; NFC"
The changes assumed pointers are 8 byte aligned on all architectures.
llvm-svn: 301429
Summary:
I plan to use WeakVH to mean "nulls itself out on deletion, but does
not track RAUW" in a subsequent commit.
Reviewers: dblaikie, davide
Reviewed By: davide
Subscribers: arsenm, mehdi_amini, mcrosier, mzolotukhin, jfb, llvm-commits, nhaehnle
Differential Revision: https://reviews.llvm.org/D32266
llvm-svn: 301424
When the location description of a source variable involves arithmetic
on the value itself, it needs to be marked with DW_OP_stack_value since it
is not describing the variable's location, but rather its value.
This is a follow-up to r297971 and fixes the source testcase quoted in
the comment in debuginfo-dce.ll.
rdar://problem/30725338
This reapplies r301093 without modifications.
llvm-svn: 301210
When the location description of a source variable involves arithmetic
on the value itself, it needs to be marked with DW_OP_stack_value since it
is not describing the variable's location, but rather its value.
This is a follow-up to r297971 and fixes the source testcase quoted in
the comment in debuginfo-dce.ll.
rdar://problem/30725338
llvm-svn: 301093
The DWARF specification knows 3 kinds of non-empty simple location
descriptions:
1. Register location descriptions
- describe a variable in a register
- consist of only a DW_OP_reg
2. Memory location descriptions
- describe the address of a variable
3. Implicit location descriptions
- describe the value of a variable
- end with DW_OP_stack_value & friends
The existing DwarfExpression code is pretty much ignorant of these
restrictions. This used to not matter because we only emitted very
short expressions that we happened to get right by accident. This
patch makes DwarfExpression aware of the rules defined by the DWARF
standard and now chooses the right kind of location description for
each expression being emitted.
This would have been an NFC commit (for the existing testsuite) if not
for the way that clang describes captured block variables. Based on
how the previous code in LLVM emitted locations, DW_OP_deref
operations that should have come at the end of the expression are put
at its beginning. Fixing this means changing the semantics of
DIExpression, so this patch bumps the version number of DIExpression
and implements a bitcode upgrade.
There are two major changes in this patch:
I had to fix the semantics of dbg.declare for describing function
arguments. After this patch a dbg.declare always takes the *address*
of a variable as the first argument, even if the argument is not an
alloca.
When lowering a DBG_VALUE, the decision of whether to emit a register
location description or a memory location description depends on the
MachineLocation — register machine locations may get promoted to
memory locations based on their DIExpression. (Future) optimization
passes that want to salvage implicit debug location for variables may
do so by appending a DW_OP_stack_value. For example:
DBG_VALUE, [RBP-8] --> DW_OP_fbreg -8
DBG_VALUE, RAX --> DW_OP_reg0 +0
DBG_VALUE, RAX, DIExpression(DW_OP_deref) --> DW_OP_reg0 +0
All testcases that were modified were regenerated from clang. I also
added source-based testcases for each of these to the debuginfo-tests
repository over the last week to make sure that no synchronized bugs
slip in. The debuginfo-tests compile from source and run the debugger.
https://bugs.llvm.org/show_bug.cgi?id=32382
<rdar://problem/31205000>
Differential Revision: https://reviews.llvm.org/D31439
llvm-svn: 300522
and to expose a handle to represent the actual case rather than having
the iterator return a reference to itself.
All of this allows the iterator to be used with common STL facilities,
standard algorithms, etc.
Doing this exposed some missing facilities in the iterator facade that
I've fixed and required some work to the actual iterator to fully
support the necessary API.
Differential Revision: https://reviews.llvm.org/D31548
llvm-svn: 300032
This moves it to the iterator facade utilities giving it full random
access semantics, etc. It can also now be used with standard algorithms
like std::all_of and std::any_of and range adaptors like llvm::reverse.
Also make the semantics of iterating match what every other iterator
uses and forbid decrementing past the begin iterator. This was used as
a hacky way to work around iterator invalidation. However, every
instance trying to do this failed to actually avoid touching invalid
iterators despite the clear documentation that the removed and all
subsequent iterators become invalid including the end iterator. So I've
added a return of the next iterator to removeCase and rewritten the
loops that were doing this to correctly follow the iterator pattern of
either incremneting or removing and assigning fresh values to the
iterator and the end.
In one case we were trying to go backwards to make this cleaner but it
doesn't actually work. I've made that code match the code we use
everywhere else to remove cases as we iterate. This changes the order of
cases in one test output and I moved that test to CHECK-DAG so it
wouldn't care -- the order isn't semantically meaningful anyways.
llvm-svn: 298791
Summary:
This class is a list of AttributeSetNodes corresponding the function
prototype of a call or function declaration. This class used to be
called ParamAttrListPtr, then AttrListPtr, then AttributeSet. It is
typically accessed by parameter and return value index, so
"AttributeList" seems like a more intuitive name.
Rename AttributeSetImpl to AttributeListImpl to follow suit.
It's useful to rename this class so that we can rename AttributeSetNode
to AttributeSet later. AttributeSet is the set of attributes that apply
to a single function, argument, or return value.
Reviewers: sanjoy, javed.absar, chandlerc, pete
Reviewed By: pete
Subscribers: pete, jholewinski, arsenm, dschuff, mehdi_amini, jfb, nhaehnle, sbc100, void, llvm-commits
Differential Revision: https://reviews.llvm.org/D31102
llvm-svn: 298393
[Reapplies r297971 and punting on finding a better API for findDbgValues()]
This patch improves debug info quality in InstCombine by looking at
values that are about to be deleted, checking whether there are any
dbg.value instrinsics referring to them, and potentially encoding the
semantics of the deleted instruction into the dbg.value's
DIExpression.
In the example in the testcase (which was extracted from XNU) there is a sequence of
%4 = load %struct.entry*, %struct.entry** %next2, align 8, !dbg !41
%5 = bitcast %struct.entry* %4 to i8*, !dbg !42
%add.ptr4 = getelementptr inbounds i8, i8* %5, i64 -8, !dbg !43
%6 = bitcast i8* %add.ptr4 to %struct.entry*, !dbg !44
call void @llvm.dbg.value(metadata %struct.entry* %6, i64 0, metadata !20, metadata !21), !dbg 34
When these instructions are eliminated by instcombine one after
another, we can still salvage the otherwise dead debug info:
- Bitcasts have no effect, so have the dbg.value point to operand(0)
- Loads can be expressed via a DW_OP_deref
- Constant gep instructions can be replaced by DWARF expression arithmetic
The API introduced by this patch is not specific to instcombine and
can be useful in other places, too.
rdar://problem/30725338
Differential Revision: https://reviews.llvm.org/D30919
llvm-svn: 297994
This patch improves debug info quality in InstCombine by looking at
values that are about to be deleted, checking whether there are any
dbg.value instrinsics referring to them, and potentially encoding the
semantics of the deleted instruction into the dbg.value's
DIExpression.
In the example in the testcase (which was extracted from XNU) there is a sequence of
%4 = load %struct.entry*, %struct.entry** %next2, align 8, !dbg !41
%5 = bitcast %struct.entry* %4 to i8*, !dbg !42
%add.ptr4 = getelementptr inbounds i8, i8* %5, i64 -8, !dbg !43
%6 = bitcast i8* %add.ptr4 to %struct.entry*, !dbg !44
call void @llvm.dbg.value(metadata %struct.entry* %6, i64 0, metadata !20, metadata !21), !dbg 34
When these instructions are eliminated by instcombine one after
another, we can still salvage the otherwise dead debug info:
- Bitcasts have no effect, so have the dbg.value point to operand(0)
- Loads can be expressed via a DW_OP_deref
- Constant gep instructions can be replaced by DWARF expression arithmetic
The API introduced by this patch is not specific to instcombine and
can be useful in other places, too.
rdar://problem/30725338
Differential Revision: https://reviews.llvm.org/D30919
llvm-svn: 297971
Summary:
The LibFunc::Func enum holds enumerators named for libc functions.
Unfortunately, there are real situations, including libc implementations, where
function names are actually macros (musl uses "#define fopen64 fopen", for
example; any other transitively visible macro would have similar effects).
Strictly speaking, a conforming C++ Standard Library should provide any such
macros as functions instead (via <cstdio>). However, there are some "library"
functions which are not part of the standard, and thus not subject to this
rule (fopen64, for example). So, in order to be both portable and consistent,
the enum should not use the bare function names.
The old enum naming used a namespace LibFunc and an enum Func, with bare
enumerators. This patch changes LibFunc to be an enum with enumerators prefixed
with "LibFFunc_". (Unfortunately, a scoped enum is not sufficient to override
macros.)
There are additional changes required in clang.
Reviewers: rsmith
Subscribers: mehdi_amini, mzolotukhin, nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D28476
llvm-svn: 292848
After r289755, the AssumptionCache is no longer needed. Variables affected by
assumptions are now found by using the new operand-bundle-based scheme. This
new scheme is more computationally efficient, and also we need much less
code...
llvm-svn: 289756
so we can stop using DW_OP_bit_piece with the wrong semantics.
The entire back story can be found here:
http://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20161114/405934.html
The gist is that in LLVM we've been misinterpreting DW_OP_bit_piece's
offset field to mean the offset into the source variable rather than
the offset into the location at the top the DWARF expression stack. In
order to be able to fix this in a subsequent patch, this patch
introduces a dedicated DW_OP_LLVM_fragment operation with the
semantics that we used to apply to DW_OP_bit_piece, which is what we
actually need while inside of LLVM. This patch is complete with a
bitcode upgrade for expressions using the old format. It does not yet
fix the DWARF backend to use DW_OP_bit_piece correctly.
Implementation note: We discussed several options for implementing
this, including reserving a dedicated field in DIExpression for the
fragment size and offset, but using an custom operator at the end of
the expression works just fine and is more efficient because we then
only pay for it when we need it.
Differential Revision: https://reviews.llvm.org/D27361
rdar://problem/29335809
llvm-svn: 288683
insertUniqueBackedgeBlock in lib/Transforms/Utils/LoopSimplify.cpp now
propagates existing llvm.loop metadata to newly the added backedge.
llvm::TryToSimplifyUncondBranchFromEmptyBlock in lib/Transforms/Utils/Local.cpp
now propagates existing llvm.loop metadata to the branch instructions in the
predecessor blocks of the empty block that is removed.
Differential Revision: https://reviews.llvm.org/D26495
llvm-svn: 287341
This adds support for TSan C++ exception handling, where we need to add extra calls to __tsan_func_exit when a function is exitted via exception mechanisms. Otherwise the shadow stack gets corrupted (leaked). This patch moves and enhances the existing implementation of EscapeEnumerator that finds all possible function exit points, and adds extra EH cleanup blocks where needed.
Differential Revision: https://reviews.llvm.org/D26177
llvm-svn: 286893
LLVM developers might be surprised to learn that there are blocks
without valid insertion points (catchswitch), so it seems worth calling
that out explicitly. Also add a FIXME about what we should really be
doing if we ever need to make optimized Windows EH code debuggable.
While I'm here, make auto usage more consistent with LLVM standards and
avoid an unecessary call to insertBefore.
llvm-svn: 282521
The additional fix is:
When adding debug information to a lowered phi node in mem2reg
check that we have a valid insertion point after the phi for adding
the debug information.
This change addresses the issue in pr30468 where a lowered phi was
added before a catchswitch and no debug information should be added
after the phi in this case.
Differential Revision: https://reviews.llvm.org/D24797
llvm-svn: 282155
The routines llvm::ConvertDebugDeclareToDebugValue() always returned
a true value which was never checked at the call site; change the
function return type to void.
This NFC cleanup was approved in the review https://reviews.llvm.org/D23715
llvm-svn: 281964
When phi nodes are created in the -mem2reg phase, the @llvm.dbg.declare
entries are converted to @llvm.dbg.value entries at the place where the
store instructions existed. However no entry is created to describe
the resulting value of the phi node.
The effect of this is especially noticeable in for loops which have a
constant for the intial value; the loop control variable's location
would be described as the intial constant value in the loop body once
the -mem2reg optimization phase was run.
This change adds the creation of the @llvm.dbg.value entries to describe
variables whose location is the result of a phi node created in -mem2reg.
Also when the phi node is finally lowered to a machine instruction it
is important that the lowered "load" instruction is placed before the
associated DEBUG_VALUE entry describing the value loaded.
Differential Revision: https://reviews.llvm.org/D23715
llvm-svn: 281895
Refactor replaceDominatedUsesWith to have a flag to control whether to replace uses in BB itself.
Summary: This is in preparation for LoopSink pass which calls replaceDominatedUsesWith to update after sinking.
llvm-svn: 280949
Summary: This is in preparation for LoopSink pass which calls replaceDominatedUsesWith to update after sinking.
Reviewers: chandlerc, davidxl, danielcdh
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D24170
llvm-svn: 280427
Summary:
The correctness fix here is that when we CSE a load with another load,
we need to combine the metadata on the two loads. This matches the
behavior of other passes, like instcombine and GVN.
There's also a minor optimization improvement here: for load PRE, the
aliasing metadata on the inserted load should be the same as the
metadata on the original load. Not sure why the old code was throwing
it away.
Issue found by inspection.
Differential Revision: http://reviews.llvm.org/D21460
llvm-svn: 277977
Sanitizers set nobuiltin attribute on certain library functions to
avoid a situation where such function is neither instrumented nor
intercepted.
At the moment the list of interesting functions is hardcoded. This
change replaces it with logic based on
TargetLibraryInfo::hasOptimizedCodegen and the presense of readnone
function attribute (sanitizers are generally interested in memory
behavior of library functions).
This is expected to be a no-op change: the new logic matches exactly
the same set of functions.
r276771 (currently reverted) added mempcpy() to the list, breaking
MSan tests. With this change, r276771 can be safely re-landed.
llvm-svn: 277086
SimplifyCFG had logic to insert calls to llvm.trap for two very
particular IR patterns: stores and invokes of undef/null.
While InstCombine canonicalizes certain undefined behavior IR patterns
to stores of undef, phase ordering means that this cannot be relied upon
in general.
There are much better tools than llvm.trap: UBSan and ASan.
N.B. I could be argued into reverting this change if a clear argument as
to why it is important that we synthesize llvm.trap for stores, I'd be
hard pressed to see why it'd be useful for invokes...
llvm-svn: 273778
r273711 was reverted by r273743. The inliner needs to know about any
call sites in the inlined function. These were obscured if we replaced
a call to undef with an undef but kept the call around.
This fixes PR28298.
llvm-svn: 273753
CodeGen has hooks that allow targets to emit specialized code instead
of calls to memcmp, memchr, strcpy, stpcpy, strcmp, strlen, strnlen.
When ASan/MSan/TSan/ESan is in use, this sidesteps its interceptors, resulting
in uninstrumented memory accesses. To avoid that, make these sanitizers
mark the calls as nobuiltin.
Differential Revision: http://reviews.llvm.org/D19781
llvm-svn: 273083
When moving unsafe allocas to the unsafe stack, dbg.declare intrinsics are
updated to refer to the new location.
This change does the same to dbg.value intrinsics.
llvm-svn: 272968
We should update results of the BranchProbabilityInfo after removing block in JumpThreading. Otherwise
we will get dangling pointer inside BranchProbabilityInfo cache.
Differential Revision: http://reviews.llvm.org/D20957
llvm-svn: 272891
Also, rename recognizeBitReverseOrBSwapIdiom to recognizeBSwapOrBitReverseIdiom,
so the ordering of the MatchBSwaps and MatchBitReversals arguments are
consistent with the function name.
llvm-svn: 270715
Make it possible that TryToSimplifyUncondBranchFromEmptyBlock merges empty
basic block including lifetime intrinsics as well as phi nodes and
unconditional branch into its successor or predecessor(s).
If successor of empty block has single predecessor, all contents including
lifetime intrinsics are sinked into the successor. Otherwise, they are
hoisted into its predecessor(s) and then merged into the predecessor(s).
Patch by Josh Yoon <josh.yoon@samsung.com>!
Differential Revision: http://reviews.llvm.org/D19257
llvm-svn: 268254
This moves some logic added to EarlyCSE in rL268120 into
`llvm::isInstructionTriviallyDead`. Adds a test case for DCE to
demonstrate that passes other than EarlyCSE can now pick up on the new
information.
llvm-svn: 268126
When SimplifyCFG merges identical instructions from both sides of a diamond, it
can preserve !llvm.mem.parallel_loop_access (as it does with most of the other
metadata). There's no real data or control dependency change in this case.
llvm-svn: 267515
Summary:
`llvm.guard(false)` always bails out of the current compilation unit, so
we can prune any control flow following it.
Reviewers: hfinkel, pcc, reames
Subscribers: majnemer, reames, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D19245
llvm-svn: 266955
This changes RS4GC to lower calls to ``@llvm.experimental.deoptimize``
to gc.statepoints wrapping ``__llvm_deoptimize``, and changes
``callsGCLeafFunction`` to recognize ``@llvm.experimental.deoptimize``
as a non GC leaf function.
I've had to hard code the ``"__llvm_deoptimize"`` name in
RewriteStatepointsForGC; since ``TargetLibraryInfo`` is available only
during codegen. This isn't without precedent in the codebase, so I'm
not overtly concerned.
llvm-svn: 264456
I missed == and != when I removed implicit conversions between iterators
and pointers in r252380 since they were defined outside ilist_iterator.
Since they depend on getNodePtrUnchecked(), they indirectly rely on UB.
This commit removes all uses of these operators. (I'll delete the
operators themselves in a separate commit so that it can be easily
reverted if necessary.)
There should be NFC here.
llvm-svn: 261498
This function is used to check whether a dbg.value intrinsic has already
been inserted, but without comparing the DIExpression, it would erroneously
fire on split aggregates and only the first scalar would survive.
Found via http://reviews.llvm.org/D16867.
<rdar://problem/24456528>
llvm-svn: 261145
SCCP has code identical to changeToUnreachable's behavior, switch it
over to just call changeToUnreachable.
No functionality change intended.
llvm-svn: 258654
InstCombine and SCCP both want to remove dead code in a very particular
way but using identical means to do so. Share the code between the two.
No functionality change is intended.
llvm-svn: 258653
platforms.
With ELF, the alignment of a global variable in a shared library will
get copied into an executables linked against it, if the executable even
accesss the variable. So, it's not possible to implicitly increase
alignment based on access patterns, or you'll break existing binaries.
This happened to affect libc++'s std::cout symbol, for example. See
thread: http://thread.gmane.org/gmane.comp.compilers.clang.devel/45311
(This is a re-commit of r257719, without the bug reported in
PR26144. I've tweaked the code to not assert-fail in
enforceKnownAlignment when computeKnownBits doesn't recurse far enough
to find the underlying Alloca/GlobalObject value.)
Differential Revision: http://reviews.llvm.org/D16145
llvm-svn: 257902
There are several requirements that ended up with this design;
1. Matching bitreversals is too heavyweight for InstCombine and doesn't really need to be done so early.
2. Bitreversals and byteswaps are very related in their matching logic.
3. We want to implement support for matching more advanced bswap/bitreverse patterns like partial bswaps/bitreverses.
4. Bswaps are best matched early in InstCombine.
The result of these is that a new utility function is created in Transforms/Utils/Local.h that can be configured to search for bswaps, bitreverses or both. InstCombine uses it to find only bswaps, CGP uses it to find only bitreversals.
We can then extend the matching logic in one place only.
llvm-svn: 257875
Summary: The dbg.declare -> dbg.value conversion did not check which operand of
the store instruction the alloca was passed to. As a result code that stored the
address of an alloca, rather than storing to the alloca, would still trigger
the conversion routine, leading to the insertion of an incorrect dbg.value
intrinsic.
Reviewers: aprantl
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D16169
llvm-svn: 257787
platforms.
With ELF, the alignment of a global variable in a shared library will
get copied into an executables linked against it, if the executable even
accesss the variable. So, it's not possible to implicitly increase
alignment based on access patterns, or you'll break existing binaries.
This happened to affect libc++'s std::cout symbol, for example. See
thread: http://thread.gmane.org/gmane.comp.compilers.clang.devel/45311
llvm-svn: 257719
Summary: The dbg.declare -> dbg.value conversion looks through any zext/sext
to find a value to describe the variable (in the expectation that those
zext/sext instruction will go away later). However, those values do not
cover the entire variable and thus need a DW_OP_bit_piece.
Reviewers: aprantl
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D16061
llvm-svn: 257534
JumpThreading's runOnFunction is supposed to return true if it made any
changes. JumpThreading has a call to removeUnreachableBlocks which may
result in changes to the IR but runOnFunction didn't appropriate account
for this possibility, leading to badness.
While we are here, make sure to call LazyValueInfo::eraseBlock in
removeUnreachableBlocks; JumpThreading preserves LVI.
This fixes PR26096.
llvm-svn: 257279
In r256814, we managed to remove catchpads which were trivially redudant
because they were the same SSA value. We can do better using the same
algorithm but with a smarter datastructure by hashing the SSA values
within the catchpad and comparing them structurally.
llvm-svn: 256815
Summary:
First up is instcombine, where in the dbg.declare -> dbg.value conversion,
the llvm.dbg.value needs to be called on the actual loaded value, rather
than the address (since the whole point of this transformation is to be
able to get rid of the alloca). Further, now that that's cleaned up, we
can remove a hack in the backend, that would add an implicit OP_deref if
the argument to dbg.value was an alloca. This stems from before the
existence of DIExpression and is no longer necessary since the deref can
be expressed explicitly.
Now, in order to make sure that the tests pass with this change, we need to
correct the printing of DEBUG_VALUE comments to take into account the
expression, which wasn't taken into account before.
Unfortunately, for both these changes, there were a number of incorrect
test cases (mostly the wrong number of DW_OP_derefs, but also a couple
where the test itself was broken more badly). aprantl and I have gone
through and adjusted these test case in order to make them pass with
these fixes and in some cases to make sure they're actually testing
what they are meant to test.
Reviewers: aprantl
Subscribers: dsanders
Differential Revision: http://reviews.llvm.org/D14186
llvm-svn: 256077
