Reverted due to an internally discovered lld crash due to the underlying
StringMap changes, which turned out to be an existing lld bug that got
tickled by the StringMap changes. That's addressed in
dee8786f70a3d62b639113343fa36ef55bdbad63 so let's have another go with
this change.
Original commit message:
lldb was rehashing the string 3 times (once to determine which StringMap
to use, once to query the StringMap, once to insert) on insertion (twice
on successful lookup).
This patch allows the lldb to benefit from hash improvements in LLVM
(from djbHash to xxh3).
Though further changes would be needed to cache this value to disk - we
shouldn't rely on the StringMap::hash remaining the same in the
future/this value should not be serialized to disk. If we want cache
this value StringMap should take a hashing template parameter to allow
for a fixed hash to be requested.
This reverts commit 5bc1adff69315dcef670e9fcbe04067b5d5963fb.
Effectively reapplying the original 2e197602305be18b963928e6ae024a004a95af6d.
Reverted due to an internally discovered lld crash, which turned out to
be an existing lld bug that got tickled by this changes. That's
addressed in dee8786f70a3d62b639113343fa36ef55bdbad63 so let's have
another go with this change.
Original commit message:
Useful for lldb's const string pool, using the hash to determine which
string map to lock and query/insert.
Derived from https://reviews.llvm.org/D122974 by Luboš Luňák
This reverts commit f976719fb2cb23364957e5993f7fc3684ee15391.
Effectively reapplying 67c631d283fc96d652304199cd625be426b98f8e.
Crash identified internally in lld's use of StringMap in
`compareSections`. Will investigate offline before recommitting.
This reverts commit 67c631d283fc96d652304199cd625be426b98f8e.
Underlying StringMap API for providing a hash has caused some problems
(observed a crash in lld) - so reverting this until I can figure out/fix
what's going on there.
This reverts commit 52ba075571958e2fec8d871ddfa1ef56486b86d3.
This reverts commit 2e197602305be18b963928e6ae024a004a95af6d.
Useful for lldb's const string pool, using the hash to determine which
string map to lock and query/insert.
Derived from https://reviews.llvm.org/D122974 by Luboš Luňák
Similar to D142862.
xxh3 is significantly faster than xxh64. Switch to xxh3, as we did for
for lld and llvm-dwarfutil to increase performance (D154813 D155675).
While I think StringMap is not a bottleneck for most applications, it
seems good to eliminate the slower xxh64.
In addition, according to Erik Desjardins, an artificial benchmark of
Rust with very large constant strings improves by ~3% locally.
I have fixed all found issues (~20) separately, but one is remaining:
* ExecutionEngine/RuntimeDyld/ARM/MachO_ARM_PIC_relocations.s has a
failure due to StringMap iteration order. It now passes
with LLVM_ENABLE_REVERSE_ITERATION=on while failing with
LLVM_ENABLE_REVERSE_ITERATION=off.
Reviewed By: erikdesjardins
Differential Revision: https://reviews.llvm.org/D155781
ProgrammersManual.html says
> StringMap iteration order, however, is not guaranteed to be deterministic, so any uses which require that should instead use a std::map.
This patch makes -DLLVM_REVERSE_ITERATION=on (currently
-DLLVM_ENABLE_REVERSE_ITERATION=on works as well) shuffle StringMap
iteration order (actually flipping the hash so that elements not in the
same bucket are reversed) to catch violations, similar to D35043 for
DenseMap. This should help change the hash function (e.g., D142862,
D155781).
With a lot of fixes, there are still some violations. This patch
implements the "reverse_iteration" lit feature to skip such tests.
Eventually we should remove this feature.
`ninja check-{llvm,clang,clang-tools}` are clean with
`#define LLVM_ENABLE_REVERSE_ITERATION 1`.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D155789
This reverts commit 37eb9d13f891f7656f811516e765b929b169afe0.
Test failures have been fixed:
- ubsan failure fixed by 72eac42f21c0f45a27f3eaaff9364cbb5189b9e4
- warn-unsafe-buffer-usage-fixits-local-var-span.cpp fixed by
03cc52dfd1dbb4a59b479da55e87838fb93d2067 (wasn't related)
- test-output-format.ll failure was spurious, build failed at
https://lab.llvm.org/buildbot/#/builders/54/builds/3545 (b4431b2d945b6fc19b1a55ac6ce969a8e06e1e93)
but passed at
https://lab.llvm.org/buildbot/#/builders/54/builds/3546 (5ae99be0377248c74346096dc475af254a3fc799)
which is before my revert
b4431b2d94...5ae99be037
Original commit message:
Depends on https://reviews.llvm.org/D142861.
Alternative to https://reviews.llvm.org/D137601.
xxHash is much faster than djbHash. This makes a simple Rust test case with a large constant string 10% faster to compile.
Previous attempts at changing this hash function (e.g. https://reviews.llvm.org/D97396) had to be reverted due to breaking tests that depended on iteration order.
No additional tests fail with this patch compared to `main` when running `check-all` with `-DLLVM_ENABLE_PROJECTS="all"` (on a Linux host), so I hope I found everything that needs to be changed.
Differential Revision: https://reviews.llvm.org/D142862
Depends on https://reviews.llvm.org/D142861.
Alternative to https://reviews.llvm.org/D137601.
xxHash is much faster than djbHash. This makes a simple Rust test case with a large constant string 10% faster to compile.
Previous attempts at changing this hash function (e.g. https://reviews.llvm.org/D97396) had to be reverted due to breaking tests that depended on iteration order.
No additional tests fail with this patch compared to `main` when running `check-all` with `-DLLVM_ENABLE_PROJECTS="all"` (on a Linux host), so I hope I found everything that needs to be changed.
Differential Revision: https://reviews.llvm.org/D142862
1. Extract createTable and getHashTable functions.
2. Add the inline attribute to the getMinBucketToReserveForEntries function.
3. Remove unnecessary local variable HTSize.
Statements in the following order appear in llvm::StringMapImpl::init and llvm::StringMapImpl::RehashTable, so I extracted this code into a function. getHashTable is for the same reason, it appears in llvm::StringMapImpl::FindKey, llvm::StringMapImpl::LookupBucketFor and llvm::StringMapImpl::RehashTable.
```
auto **Table = static_cast<StringMapEntryBase **>(safe_calloc(
NewNumBuckets + 1, sizeof(StringMapEntryBase **) + sizeof(unsigned)));
// Allocate one extra bucket, set it to look filled so the iterators stop at
// end.
Table[NewNumBuckets] = (StringMapEntryBase *)2;
```
```
unsigned *HashTable = (unsigned *)(TheTable + NumBuckets + 1);
```
Reviewed By: skan, sepavloff
Differential Revision: https://reviews.llvm.org/D121934
The cleanup was manual, but assisted by "include-what-you-use". It consists in
1. Removing unused forward declaration. No impact expected.
2. Removing unused headers in .cpp files. No impact expected.
3. Removing unused headers in .h files. This removes implicit dependencies and
is generally considered a good thing, but this may break downstream builds.
I've updated llvm, clang, lld, lldb and mlir deps, and included a list of the
modification in the second part of the commit.
4. Replacing header inclusion by forward declaration. This has the same impact
as 3.
Notable changes:
- llvm/Support/TargetParser.h no longer includes llvm/Support/AArch64TargetParser.h nor llvm/Support/ARMTargetParser.h
- llvm/Support/TypeSize.h no longer includes llvm/Support/WithColor.h
- llvm/Support/YAMLTraits.h no longer includes llvm/Support/Regex.h
- llvm/ADT/SmallVector.h no longer includes llvm/Support/MemAlloc.h nor llvm/Support/ErrorHandling.h
You may need to add some of these headers in your compilation units, if needs be.
As an hint to the impact of the cleanup, running
clang++ -E -Iinclude -I../llvm/include ../llvm/lib/Support/*.cpp -std=c++14 -fno-rtti -fno-exceptions | wc -l
before: 8000919 lines
after: 7917500 lines
Reduced dependencies also helps incremental rebuilds and is more ccache
friendly, something not shown by the above metric :-)
Discourse thread on the topic: https://llvm.discourse.group/t/include-what-you-use-include-cleanup/5831
See original comment in 560ce2c70fb1fe8e4b9b5e39c54e494a50373ba8
Baiscally the default seed value results in less collision, but changes the
iteration order, which matters for a few test cases.
Differential Revision: https://reviews.llvm.org/D97396
Summary:
StringMapEntry.h can have lower dependencies, than StringMap.h, which
is useful for public headers that want to expose inline methods on
StringMapEntry<> but don't need to expose all of StringMap.h. One
example of this is mlir's Identifier.h, another example is the existing
LLVM StringPool.h.
StringPool also could use a cleanup, I'll deal with that in a follow-on
patch.
Reviewers: rriddle
Subscribers: hiraditya, dexonsmith, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77963
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
This is a recommit of r333506, which was reverted in r333518.
The original commit message is below.
In r325551 many calls of malloc/calloc/realloc were replaces with calls of
their safe counterparts defined in the namespace llvm. There functions
generate crash if memory cannot be allocated, such behavior facilitates
handling of out of memory errors on Windows.
If the result of *alloc function were checked for success, the function was
not replaced with the safe variant. In these cases the calling function made
the error handling, like:
T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T)));
if (NewElts == nullptr)
report_bad_alloc_error("Allocation of SmallVector element failed.");
Actually knowledge about the function where OOM occurred is useless. Moreover
having a single entry point for OOM handling is convenient for investigation
of memory problems. This change removes custom OOM errors handling and
replaces them with calls to functions `llvm::safe_*alloc`.
Declarations of `safe_*alloc` are moved to a separate include file, to avoid
cyclic dependency in SmallVector.h
Differential Revision: https://reviews.llvm.org/D47440
llvm-svn: 334344
This is a recommit of r333390, which was reverted in r333395, because it
caused cyclic dependency when building shared library `LLVMDemangle.so`.
In this commit `ItaniumDemangler.cpp` was not changed.
The original commit message is below.
In r325551 many calls of malloc/calloc/realloc were replaces with calls of
their safe counterparts defined in the namespace llvm. There functions
generate crash if memory cannot be allocated, such behavior facilitates
handling of out of memory errors on Windows.
If the result of *alloc function were checked for success, the function was
not replaced with the safe variant. In these cases the calling function made
the error handling, like:
T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T)));
if (NewElts == nullptr)
report_bad_alloc_error("Allocation of SmallVector element failed.");
Actually knowledge about the function where OOM occurred is useless. Moreover
having a single entry point for OOM handling is convenient for investigation
of memory problems. This change removes custom OOM errors handling and
replaces them with calls to functions `llvm::safe_*alloc`.
Declarations of `safe_*alloc` are moved to a separate include file, to avoid
cyclic dependency in SmallVector.h
Differential Revision: https://reviews.llvm.org/D47440
llvm-svn: 333506
In r325551 many calls of malloc/calloc/realloc were replaces with calls of
their safe counterparts defined in the namespace llvm. There functions
generate crash if memory cannot be allocated, such behavior facilitates
handling of out of memory errors on Windows.
If the result of *alloc function were checked for success, the function was
not replaced with the safe variant. In these cases the calling function made
the error handling, like:
T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T)));
if (NewElts == nullptr)
report_bad_alloc_error("Allocation of SmallVector element failed.");
Actually knowledge about the function where OOM occurred is useless. Moreover
having a single entry point for OOM handling is convenient for investigation
of memory problems. This change removes custom OOM errors handling and
replaces them with calls to functions `llvm::safe_*alloc`.
Declarations of `safe_*alloc` are moved to a separate include file, to avoid
cyclic dependency in SmallVector.h
Differential Revision: https://reviews.llvm.org/D47440
llvm-svn: 333390
This patch removes the HashString function from StringExtraces and
replaces its uses with calls to djbHash from DJB.h.
This change is *almost* NFC. While the algorithm is identical, the
djbHash implementation in StringExtras used 0 as its default seed while
the implementation in DJB uses 5381. The latter has been shown to result
in less collisions and improved avalanching and is used by the DWARF
accelerator tables.
Because some test were implicitly relying on the hash order, I've
reverted to using zero as a seed for the following two files:
lld/include/lld/Core/SymbolTable.h
llvm/lib/Support/StringMap.cpp
Differential revision: https://reviews.llvm.org/D43615
llvm-svn: 326091
It looks like some of our tests depend on the ordering of hashed values.
I'm reverting my changes while I try to reproduce and fix this locally.
Failing builds:
lab.llvm.org:8011/builders/lld-x86_64-darwin13/builds/18388
lab.llvm.org:8011/builders/clang-cmake-x86_64-sde-avx512-linux/builds/6743
lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-windows10pro-fast/builds/15607
llvm-svn: 326082
This removes the HashString function from StringExtraces and replaces
its uses with calls to djbHash from DJB.h
This is *almost* NFC. While the algorithm is identical, the djbHash
implementation in StringExtras used 0 as its seed while the
implementation in DJB uses 5381. The latter has been shown to result in
less collisions and improved avalanching.
https://reviews.llvm.org/D43615
(cherry picked from commit 77f7f965bc9499a9ae768a296ca5a1f7347d1d2c)
llvm-svn: 326081
This is the second part of recommit of r325224. The previous part was
committed in r325426, which deals with C++ memory allocation. Solution
for C memory allocation involved functions `llvm::malloc` and similar.
This was a fragile solution because it caused ambiguity errors in some
cases. In this commit the new functions have names like `llvm::safe_malloc`.
The relevant part of original comment is below, updated for new function
names.
Analysis of fails in the case of out of memory errors can be tricky on
Windows. Such error emerges at the point where memory allocation function
fails, but manifests itself when null pointer is used. These two points
may be distant from each other. Besides, next runs may not exhibit
allocation error.
In some cases memory is allocated by a call to some of C allocation
functions, malloc, calloc and realloc. They are used for interoperability
with C code, when allocated object has variable size and when it is
necessary to avoid call of constructors. In many calls the result is not
checked for null pointer. To simplify checks, new functions are defined
in the namespace 'llvm': `safe_malloc`, `safe_calloc` and `safe_realloc`.
They behave as corresponding standard functions but produce fatal error if
allocation fails. This change replaces the standard functions like 'malloc'
in the cases when the result of the allocation function is not checked
for null pointer.
Finally, there are plain C code, that uses malloc and similar functions. If
the result is not checked, assert statement is added.
Differential Revision: https://reviews.llvm.org/D43010
llvm-svn: 325551
Analysis of fails in the case of out of memory errors can be tricky on
Windows. Such error emerges at the point where memory allocation function
fails, but manifests itself when null pointer is used. These two points
may be distant from each other. Besides, next runs may not exhibit
allocation error.
Usual programming practice does not require checking result of 'operator
new' because it throws 'std::bad_alloc' in the case of allocation error.
However, LLVM is usually built with exceptions turned off, so 'new' can
return null pointer. This change installs custom new handler, which causes
fatal error in the case of out of memory. The handler is installed
automatically prior to call to 'main' during construction of a static
object defined in 'lib/Support/ErrorHandling.cpp'. If the application does
not use this file, the handler may be installed manually by a call to
'llvm::install_out_of_memory_new_handler', declared in
'include/llvm/Support/ErrorHandling.h".
There are calls to C allocation functions, malloc, calloc and realloc.
They are used for interoperability with C code, when allocated object has
variable size and when it is necessary to avoid call of constructors. In
many calls the result is not checked against null pointer. To simplify
checks, new functions are defined in the namespace 'llvm' with the
same names as these C function. These functions produce fatal error if
allocation fails. User should use 'llvm::malloc' instead of 'std::malloc'
in order to use the safe variant. This change replaces 'std::malloc'
in the cases when the result of allocation function is not checked against
null pointer.
Finally, there are plain C code, that uses malloc and similar functions. If
the result is not checked, assert statements are added.
Differential Revision: https://reviews.llvm.org/D43010
llvm-svn: 325224
As a follow up of the bad alloc handler patch, this patch introduces nullptr checks on pointers returned from the
malloc/realloc/calloc functions. In addition some memory size assignments are moved behind the allocation
of the corresponding memory to fulfill exception safe memory management (RAII).
patch by Klaus Kretzschmar
Differential Revision: https://reviews.llvm.org/D35414
llvm-svn: 308576
Summary:
StringMap ctor accepts an initialize size, but expect it to be
rounded to the next power of 2. The ctor can handle that directly
instead of expecting clients to round it. Also, since the map will
resize itself when 75% full, take this into account an initialize
a larger initial size to avoid any growth.
Reviewers: dblaikie
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D18344
From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 264385
This assumes that
a) finding the bucket containing the value is LIKELY
b) finding an empty bucket is LIKELY
c) growing the table is UNLIKELY
I also switched the a) and b) cases for SmallPtrSet as we seem to use
the set mostly more for insertion than for checking existence.
In a simple benchmark consisting of 2^21 insertions of 2^20 unique
pointers into a DenseMap or SmallPtrSet a few percent speedup on average,
but nothing statistically significant.
llvm-svn: 230232
Certain versions of GCC (~4.7) couldn't handle the SFINAE on access
control, but with "= delete" (hidden behind a macro for portability)
this issue is worked around/addressed.
Patch by Agustín Bergé
llvm-svn: 211525
Tombstones and full hash collisions are rare, mark the "empty"
and "no collision" paths as likely. The bug in simplifycfg
that prevented the hints from being picked during selfhost
up was fixed recently :)
llvm-svn: 162874
StringMap suffered from the same bug as DenseMap: when you explicitly
construct it with a small number of buckets, you can arrange for the
tombstone-based growth path to be followed when the number of buckets
was less than '8'. In that case, even with a full map, it would compare
'0' as not less than '0', and refuse to grow the table, leading to
inf-loops trying to find an empty bucket on the next insertion. The fix
is very simple: use '<=' as the comparison. The same fix was applied to
DenseMap as well during its recent refactoring.
Thanks to Alex Bolz for the great report and test case. =]
llvm-svn: 158725
StringMap was not properly updating NumTombstones after a clear or rehash.
This was not fatal until now because the table was growing faster than
NumTombstones could, but with the previous change of preventing infinite
growth of the table the invariant (NumItems + NumTombstones <= NumBuckets)
stopped being observed, causing infinite loops in certain situations.
Patch by José Fonseca!
llvm-svn: 128567
- Yay for '-'s and simplifications!
- I kept StringMap::GetOrCreateValue for compatibility purposes, this can
eventually go away. Likewise the StringMapEntry Create functions still follow
the old style.
- NIFC.
llvm-svn: 76888
