Remove dead virtual functions from vtables with
replaceNonMetadataUsesWith, so that CGProfile metadata gets cleaned up
correctly.
Original commit message:
Currently, it is hard for the compiler to remove unused C++ virtual
functions, because they are all referenced from vtables, which are referenced
by constructors. This means that if the constructor is called from any live
code, then we keep every virtual function in the final link, even if there
are no call sites which can use it.
This patch allows unused virtual functions to be removed during LTO (and
regular compilation in limited circumstances) by using type metadata to match
virtual function call sites to the vtable slots they might load from. This
information can then be used in the global dead code elimination pass instead
of the references from vtables to virtual functions, to more accurately
determine which functions are reachable.
To make this transformation safe, I have changed clang's code-generation to
always load virtual function pointers using the llvm.type.checked.load
intrinsic, instead of regular load instructions. I originally tried writing
this using clang's existing code-generation, which uses the llvm.type.test
and llvm.assume intrinsics after doing a normal load. However, it is possible
for optimisations to obscure the relationship between the GEP, load and
llvm.type.test, causing GlobalDCE to fail to find virtual function call
sites.
The existing linkage and visibility types don't accurately describe the scope
in which a virtual call could be made which uses a given vtable. This is
wider than the visibility of the type itself, because a virtual function call
could be made using a more-visible base class. I've added a new
!vcall_visibility metadata type to represent this, described in
TypeMetadata.rst. The internalization pass and libLTO have been updated to
change this metadata when linking is performed.
This doesn't currently work with ThinLTO, because it needs to see every call
to llvm.type.checked.load in the linkage unit. It might be possible to
extend this optimisation to be able to use the ThinLTO summary, as was done
for devirtualization, but until then that combination is rejected in the
clang driver.
To test this, I've written a fuzzer which generates random C++ programs with
complex class inheritance graphs, and virtual functions called through object
and function pointers of different types. The programs are spread across
multiple translation units and DSOs to test the different visibility
restrictions.
I've also tried doing bootstrap builds of LLVM to test this. This isn't
ideal, because only classes in anonymous namespaces can be optimised with
-fvisibility=default, and some parts of LLVM (plugins and bugpoint) do not
work correctly with -fvisibility=hidden. However, there are only 12 test
failures when building with -fvisibility=hidden (and an unmodified compiler),
and this change does not cause any new failures for either value of
-fvisibility.
On the 7 C++ sub-benchmarks of SPEC2006, this gives a geomean code-size
reduction of ~6%, over a baseline compiled with "-O2 -flto
-fvisibility=hidden -fwhole-program-vtables". The best cases are reductions
of ~14% in 450.soplex and 483.xalancbmk, and there are no code size
increases.
I've also run this on a set of 8 mbed-os examples compiled for Armv7M, which
show a geomean size reduction of ~3%, again with no size increases.
I had hoped that this would have no effect on performance, which would allow
it to awlays be enabled (when using -fwhole-program-vtables). However, the
changes in clang to use the llvm.type.checked.load intrinsic are causing ~1%
performance regression in the C++ parts of SPEC2006. It should be possible to
recover some of this perf loss by teaching optimisations about the
llvm.type.checked.load intrinsic, which would make it worth turning this on
by default (though it's still dependent on -fwhole-program-vtables).
Differential revision: https://reviews.llvm.org/D63932
llvm-svn: 375094
When on windows gnu-ar treats member names as case insensitive. This
commit implements the same behaviour.
Differential Revision: https://reviews.llvm.org/D68033
llvm-svn: 375002
Summary:
Internally in LLVM's metadata we use DW_OP_entry_value operations with
the same semantics as DWARF; that is, its operand specifies the number
of bytes that the entry value covers.
At the time of emitting entry values we don't know the emitted size of
the DWARF expression that the entry value will cover. Currently the size
is hardcoded to 1 in DIExpression, and other values causes the verifier
to fail. As the size is 1, that effectively means that we can only have
valid entry values for registers that can be encoded in one byte, which
are the registers with DWARF numbers 0 to 31 (as they can be encoded as
single-byte DW_OP_reg0..DW_OP_reg31 rather than a multi-byte
DW_OP_regx). It is a bit confusing, but it seems like llvm-dwarfdump
will print an operation "correctly", even if the byte size is less than
that, which may make it seem that we emit correct DWARF for registers
with DWARF numbers > 31. If you instead use readelf for such cases, it
will interpret the number of specified bytes as a DWARF expression. This
seems like a limitation in llvm-dwarfdump.
As suggested in D66746, a way forward would be to add an internal
variant of DW_OP_entry_value, DW_OP_LLVM_entry_value, whose operand
instead specifies the number of operations that the entry value covers,
and we then translate that into the byte size at the time of emission.
In this patch that internal operation is added. This patch keeps the
limitation that a entry value can only be applied to simple register
locations, but it will fix the issue with the size operand being
incorrect for DWARF numbers > 31.
Reviewers: aprantl, vsk, djtodoro, NikolaPrica
Reviewed By: aprantl
Subscribers: jyknight, fedor.sergeev, hiraditya, llvm-commits
Tags: #debug-info, #llvm
Differential Revision: https://reviews.llvm.org/D67492
llvm-svn: 374881
Summary:
This is a recommit, this originally landed in rL370454 but was
subsequently reverted in rL370788 due to
https://bugs.llvm.org/show_bug.cgi?id=43206
The reduced testcase was added to bcmp-negative-tests.ll
as @pr43206_different_loops - we must ensure that the SCEV's
we got are both for the same loop we are currently investigating.
Original commit message:
@mclow.lists brought up this issue up in IRC.
It is a reasonably common problem to compare some two values for equality.
Those may be just some integers, strings or arrays of integers.
In C, there is `memcmp()`, `bcmp()` functions.
In C++, there exists `std::equal()` algorithm.
One can also write that function manually.
libstdc++'s `std::equal()` is specialized to directly call `memcmp()` for
various types, but not `std::byte` from C++2a. https://godbolt.org/z/mx2ejJ
libc++ does not do anything like that, it simply relies on simple C++'s
`operator==()`. https://godbolt.org/z/er0Zwf (GOOD!)
So likely, there exists a certain performance opportunities.
Let's compare performance of naive `std::equal()` (no `memcmp()`) with one that
is using `memcmp()` (in this case, compiled with modified compiler). {F8768213}
```
#include <algorithm>
#include <cmath>
#include <cstdint>
#include <iterator>
#include <limits>
#include <random>
#include <type_traits>
#include <utility>
#include <vector>
#include "benchmark/benchmark.h"
template <class T>
bool equal(T* a, T* a_end, T* b) noexcept {
for (; a != a_end; ++a, ++b) {
if (*a != *b) return false;
}
return true;
}
template <typename T>
std::vector<T> getVectorOfRandomNumbers(size_t count) {
std::random_device rd;
std::mt19937 gen(rd());
std::uniform_int_distribution<T> dis(std::numeric_limits<T>::min(),
std::numeric_limits<T>::max());
std::vector<T> v;
v.reserve(count);
std::generate_n(std::back_inserter(v), count,
[&dis, &gen]() { return dis(gen); });
assert(v.size() == count);
return v;
}
struct Identical {
template <typename T>
static std::pair<std::vector<T>, std::vector<T>> Gen(size_t count) {
auto Tmp = getVectorOfRandomNumbers<T>(count);
return std::make_pair(Tmp, std::move(Tmp));
}
};
struct InequalHalfway {
template <typename T>
static std::pair<std::vector<T>, std::vector<T>> Gen(size_t count) {
auto V0 = getVectorOfRandomNumbers<T>(count);
auto V1 = V0;
V1[V1.size() / size_t(2)]++; // just change the value.
return std::make_pair(std::move(V0), std::move(V1));
}
};
template <class T, class Gen>
void BM_bcmp(benchmark::State& state) {
const size_t Length = state.range(0);
const std::pair<std::vector<T>, std::vector<T>> Data =
Gen::template Gen<T>(Length);
const std::vector<T>& a = Data.first;
const std::vector<T>& b = Data.second;
assert(a.size() == Length && b.size() == a.size());
benchmark::ClobberMemory();
benchmark::DoNotOptimize(a);
benchmark::DoNotOptimize(a.data());
benchmark::DoNotOptimize(b);
benchmark::DoNotOptimize(b.data());
for (auto _ : state) {
const bool is_equal = equal(a.data(), a.data() + a.size(), b.data());
benchmark::DoNotOptimize(is_equal);
}
state.SetComplexityN(Length);
state.counters["eltcnt"] =
benchmark::Counter(Length, benchmark::Counter::kIsIterationInvariant);
state.counters["eltcnt/sec"] =
benchmark::Counter(Length, benchmark::Counter::kIsIterationInvariantRate);
const size_t BytesRead = 2 * sizeof(T) * Length;
state.counters["bytes_read/iteration"] =
benchmark::Counter(BytesRead, benchmark::Counter::kDefaults,
benchmark::Counter::OneK::kIs1024);
state.counters["bytes_read/sec"] = benchmark::Counter(
BytesRead, benchmark::Counter::kIsIterationInvariantRate,
benchmark::Counter::OneK::kIs1024);
}
template <typename T>
static void CustomArguments(benchmark::internal::Benchmark* b) {
const size_t L2SizeBytes = []() {
for (const benchmark::CPUInfo::CacheInfo& I :
benchmark::CPUInfo::Get().caches) {
if (I.level == 2) return I.size;
}
return 0;
}();
// What is the largest range we can check to always fit within given L2 cache?
const size_t MaxLen = L2SizeBytes / /*total bufs*/ 2 /
/*maximal elt size*/ sizeof(T) / /*safety margin*/ 2;
b->RangeMultiplier(2)->Range(1, MaxLen)->Complexity(benchmark::oN);
}
BENCHMARK_TEMPLATE(BM_bcmp, uint8_t, Identical)
->Apply(CustomArguments<uint8_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint16_t, Identical)
->Apply(CustomArguments<uint16_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint32_t, Identical)
->Apply(CustomArguments<uint32_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint64_t, Identical)
->Apply(CustomArguments<uint64_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint8_t, InequalHalfway)
->Apply(CustomArguments<uint8_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint16_t, InequalHalfway)
->Apply(CustomArguments<uint16_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint32_t, InequalHalfway)
->Apply(CustomArguments<uint32_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint64_t, InequalHalfway)
->Apply(CustomArguments<uint64_t>);
```
{F8768210}
```
$ ~/src/googlebenchmark/tools/compare.py --no-utest benchmarks build-{old,new}/test/llvm-bcmp-bench
RUNNING: build-old/test/llvm-bcmp-bench --benchmark_out=/tmp/tmpb6PEUx
2019-04-25 21:17:11
Running build-old/test/llvm-bcmp-bench
Run on (8 X 4000 MHz CPU s)
CPU Caches:
L1 Data 16K (x8)
L1 Instruction 64K (x4)
L2 Unified 2048K (x4)
L3 Unified 8192K (x1)
Load Average: 0.65, 3.90, 4.14
---------------------------------------------------------------------------------------------------
Benchmark Time CPU Iterations UserCounters...
---------------------------------------------------------------------------------------------------
<...>
BM_bcmp<uint8_t, Identical>/512000 432131 ns 432101 ns 1613 bytes_read/iteration=1000k bytes_read/sec=2.20706G/s eltcnt=825.856M eltcnt/sec=1.18491G/s
BM_bcmp<uint8_t, Identical>_BigO 0.86 N 0.86 N
BM_bcmp<uint8_t, Identical>_RMS 8 % 8 %
<...>
BM_bcmp<uint16_t, Identical>/256000 161408 ns 161409 ns 4027 bytes_read/iteration=1000k bytes_read/sec=5.90843G/s eltcnt=1030.91M eltcnt/sec=1.58603G/s
BM_bcmp<uint16_t, Identical>_BigO 0.67 N 0.67 N
BM_bcmp<uint16_t, Identical>_RMS 25 % 25 %
<...>
BM_bcmp<uint32_t, Identical>/128000 81497 ns 81488 ns 8415 bytes_read/iteration=1000k bytes_read/sec=11.7032G/s eltcnt=1077.12M eltcnt/sec=1.57078G/s
BM_bcmp<uint32_t, Identical>_BigO 0.71 N 0.71 N
BM_bcmp<uint32_t, Identical>_RMS 42 % 42 %
<...>
BM_bcmp<uint64_t, Identical>/64000 50138 ns 50138 ns 10909 bytes_read/iteration=1000k bytes_read/sec=19.0209G/s eltcnt=698.176M eltcnt/sec=1.27647G/s
BM_bcmp<uint64_t, Identical>_BigO 0.84 N 0.84 N
BM_bcmp<uint64_t, Identical>_RMS 27 % 27 %
<...>
BM_bcmp<uint8_t, InequalHalfway>/512000 192405 ns 192392 ns 3638 bytes_read/iteration=1000k bytes_read/sec=4.95694G/s eltcnt=1.86266G eltcnt/sec=2.66124G/s
BM_bcmp<uint8_t, InequalHalfway>_BigO 0.38 N 0.38 N
BM_bcmp<uint8_t, InequalHalfway>_RMS 3 % 3 %
<...>
BM_bcmp<uint16_t, InequalHalfway>/256000 127858 ns 127860 ns 5477 bytes_read/iteration=1000k bytes_read/sec=7.45873G/s eltcnt=1.40211G eltcnt/sec=2.00219G/s
BM_bcmp<uint16_t, InequalHalfway>_BigO 0.50 N 0.50 N
BM_bcmp<uint16_t, InequalHalfway>_RMS 0 % 0 %
<...>
BM_bcmp<uint32_t, InequalHalfway>/128000 49140 ns 49140 ns 14281 bytes_read/iteration=1000k bytes_read/sec=19.4072G/s eltcnt=1.82797G eltcnt/sec=2.60478G/s
BM_bcmp<uint32_t, InequalHalfway>_BigO 0.40 N 0.40 N
BM_bcmp<uint32_t, InequalHalfway>_RMS 18 % 18 %
<...>
BM_bcmp<uint64_t, InequalHalfway>/64000 32101 ns 32099 ns 21786 bytes_read/iteration=1000k bytes_read/sec=29.7101G/s eltcnt=1.3943G eltcnt/sec=1.99381G/s
BM_bcmp<uint64_t, InequalHalfway>_BigO 0.50 N 0.50 N
BM_bcmp<uint64_t, InequalHalfway>_RMS 1 % 1 %
RUNNING: build-new/test/llvm-bcmp-bench --benchmark_out=/tmp/tmpQ46PP0
2019-04-25 21:19:29
Running build-new/test/llvm-bcmp-bench
Run on (8 X 4000 MHz CPU s)
CPU Caches:
L1 Data 16K (x8)
L1 Instruction 64K (x4)
L2 Unified 2048K (x4)
L3 Unified 8192K (x1)
Load Average: 1.01, 2.85, 3.71
---------------------------------------------------------------------------------------------------
Benchmark Time CPU Iterations UserCounters...
---------------------------------------------------------------------------------------------------
<...>
BM_bcmp<uint8_t, Identical>/512000 18593 ns 18590 ns 37565 bytes_read/iteration=1000k bytes_read/sec=51.2991G/s eltcnt=19.2333G eltcnt/sec=27.541G/s
BM_bcmp<uint8_t, Identical>_BigO 0.04 N 0.04 N
BM_bcmp<uint8_t, Identical>_RMS 37 % 37 %
<...>
BM_bcmp<uint16_t, Identical>/256000 18950 ns 18948 ns 37223 bytes_read/iteration=1000k bytes_read/sec=50.3324G/s eltcnt=9.52909G eltcnt/sec=13.511G/s
BM_bcmp<uint16_t, Identical>_BigO 0.08 N 0.08 N
BM_bcmp<uint16_t, Identical>_RMS 34 % 34 %
<...>
BM_bcmp<uint32_t, Identical>/128000 18627 ns 18627 ns 37895 bytes_read/iteration=1000k bytes_read/sec=51.198G/s eltcnt=4.85056G eltcnt/sec=6.87168G/s
BM_bcmp<uint32_t, Identical>_BigO 0.16 N 0.16 N
BM_bcmp<uint32_t, Identical>_RMS 35 % 35 %
<...>
BM_bcmp<uint64_t, Identical>/64000 18855 ns 18855 ns 37458 bytes_read/iteration=1000k bytes_read/sec=50.5791G/s eltcnt=2.39731G eltcnt/sec=3.3943G/s
BM_bcmp<uint64_t, Identical>_BigO 0.32 N 0.32 N
BM_bcmp<uint64_t, Identical>_RMS 33 % 33 %
<...>
BM_bcmp<uint8_t, InequalHalfway>/512000 9570 ns 9569 ns 73500 bytes_read/iteration=1000k bytes_read/sec=99.6601G/s eltcnt=37.632G eltcnt/sec=53.5046G/s
BM_bcmp<uint8_t, InequalHalfway>_BigO 0.02 N 0.02 N
BM_bcmp<uint8_t, InequalHalfway>_RMS 29 % 29 %
<...>
BM_bcmp<uint16_t, InequalHalfway>/256000 9547 ns 9547 ns 74343 bytes_read/iteration=1000k bytes_read/sec=99.8971G/s eltcnt=19.0318G eltcnt/sec=26.8159G/s
BM_bcmp<uint16_t, InequalHalfway>_BigO 0.04 N 0.04 N
BM_bcmp<uint16_t, InequalHalfway>_RMS 29 % 29 %
<...>
BM_bcmp<uint32_t, InequalHalfway>/128000 9396 ns 9394 ns 73521 bytes_read/iteration=1000k bytes_read/sec=101.518G/s eltcnt=9.41069G eltcnt/sec=13.6255G/s
BM_bcmp<uint32_t, InequalHalfway>_BigO 0.08 N 0.08 N
BM_bcmp<uint32_t, InequalHalfway>_RMS 30 % 30 %
<...>
BM_bcmp<uint64_t, InequalHalfway>/64000 9499 ns 9498 ns 73802 bytes_read/iteration=1000k bytes_read/sec=100.405G/s eltcnt=4.72333G eltcnt/sec=6.73808G/s
BM_bcmp<uint64_t, InequalHalfway>_BigO 0.16 N 0.16 N
BM_bcmp<uint64_t, InequalHalfway>_RMS 28 % 28 %
Comparing build-old/test/llvm-bcmp-bench to build-new/test/llvm-bcmp-bench
Benchmark Time CPU Time Old Time New CPU Old CPU New
---------------------------------------------------------------------------------------------------------------------------------------
<...>
BM_bcmp<uint8_t, Identical>/512000 -0.9570 -0.9570 432131 18593 432101 18590
<...>
BM_bcmp<uint16_t, Identical>/256000 -0.8826 -0.8826 161408 18950 161409 18948
<...>
BM_bcmp<uint32_t, Identical>/128000 -0.7714 -0.7714 81497 18627 81488 18627
<...>
BM_bcmp<uint64_t, Identical>/64000 -0.6239 -0.6239 50138 18855 50138 18855
<...>
BM_bcmp<uint8_t, InequalHalfway>/512000 -0.9503 -0.9503 192405 9570 192392 9569
<...>
BM_bcmp<uint16_t, InequalHalfway>/256000 -0.9253 -0.9253 127858 9547 127860 9547
<...>
BM_bcmp<uint32_t, InequalHalfway>/128000 -0.8088 -0.8088 49140 9396 49140 9394
<...>
BM_bcmp<uint64_t, InequalHalfway>/64000 -0.7041 -0.7041 32101 9499 32099 9498
```
What can we tell from the benchmark?
* Performance of naive equality check somewhat improves with element size,
maxing out at eltcnt/sec=1.58603G/s for uint16_t, or bytes_read/sec=19.0209G/s
for uint64_t. I think, that instability implies performance problems.
* Performance of `memcmp()`-aware benchmark always maxes out at around
bytes_read/sec=51.2991G/s for every type. That is 2.6x the throughput of the
naive variant!
* eltcnt/sec metric for the `memcmp()`-aware benchmark maxes out at
eltcnt/sec=27.541G/s for uint8_t (was: eltcnt/sec=1.18491G/s, so 24x) and
linearly decreases with element size.
For uint64_t, it's ~4x+ the elements/second.
* The call obvious is more pricey than the loop, with small element count.
As it can be seen from the full output {F8768210}, the `memcmp()` is almost
universally worse, independent of the element size (and thus buffer size) when
element count is less than 8.
So all in all, bcmp idiom does indeed pose untapped performance headroom.
This diff does implement said idiom recognition. I think a reasonable test
coverage is present, but do tell if there is anything obvious missing.
Now, quality. This does succeed to build and pass the test-suite, at least
without any non-bundled elements. {F8768216} {F8768217}
This transform fires 91 times:
```
$ /build/test-suite/utils/compare.py -m loop-idiom.NumBCmp result-new.json
Tests: 1149
Metric: loop-idiom.NumBCmp
Program result-new
MultiSourc...Benchmarks/7zip/7zip-benchmark 79.00
MultiSource/Applications/d/make_dparser 3.00
SingleSource/UnitTests/vla 2.00
MultiSource/Applications/Burg/burg 1.00
MultiSourc.../Applications/JM/lencod/lencod 1.00
MultiSource/Applications/lemon/lemon 1.00
MultiSource/Benchmarks/Bullet/bullet 1.00
MultiSourc...e/Benchmarks/MallocBench/gs/gs 1.00
MultiSourc...gs-C/TimberWolfMC/timberwolfmc 1.00
MultiSourc...Prolangs-C/simulator/simulator 1.00
```
The size changes are:
I'm not sure what's going on with SingleSource/UnitTests/vla.test yet, did not look.
```
$ /build/test-suite/utils/compare.py -m size..text result-{old,new}.json --filter-hash
Tests: 1149
Same hash: 907 (filtered out)
Remaining: 242
Metric: size..text
Program result-old result-new diff
test-suite...ingleSource/UnitTests/vla.test 753.00 833.00 10.6%
test-suite...marks/7zip/7zip-benchmark.test 1001697.00 966657.00 -3.5%
test-suite...ngs-C/simulator/simulator.test 32369.00 32321.00 -0.1%
test-suite...plications/d/make_dparser.test 89585.00 89505.00 -0.1%
test-suite...ce/Applications/Burg/burg.test 40817.00 40785.00 -0.1%
test-suite.../Applications/lemon/lemon.test 47281.00 47249.00 -0.1%
test-suite...TimberWolfMC/timberwolfmc.test 250065.00 250113.00 0.0%
test-suite...chmarks/MallocBench/gs/gs.test 149889.00 149873.00 -0.0%
test-suite...ications/JM/lencod/lencod.test 769585.00 769569.00 -0.0%
test-suite.../Benchmarks/Bullet/bullet.test 770049.00 770049.00 0.0%
test-suite...HMARK_ANISTROPIC_DIFFUSION/128 NaN NaN nan%
test-suite...HMARK_ANISTROPIC_DIFFUSION/256 NaN NaN nan%
test-suite...CHMARK_ANISTROPIC_DIFFUSION/64 NaN NaN nan%
test-suite...CHMARK_ANISTROPIC_DIFFUSION/32 NaN NaN nan%
test-suite...ENCHMARK_BILATERAL_FILTER/64/4 NaN NaN nan%
Geomean difference nan%
result-old result-new diff
count 1.000000e+01 10.00000 10.000000
mean 3.152090e+05 311695.40000 0.006749
std 3.790398e+05 372091.42232 0.036605
min 7.530000e+02 833.00000 -0.034981
25% 4.243300e+04 42401.00000 -0.000866
50% 1.197370e+05 119689.00000 -0.000392
75% 6.397050e+05 639705.00000 -0.000005
max 1.001697e+06 966657.00000 0.106242
```
I don't have timings though.
And now to the code. The basic idea is to completely replace the whole loop.
If we can't fully kill it, don't transform.
I have left one or two comments in the code, so hopefully it can be understood.
Also, there is a few TODO's that i have left for follow-ups:
* widening of `memcmp()`/`bcmp()`
* step smaller than the comparison size
* Metadata propagation
* more than two blocks as long as there is still a single backedge?
* ???
Reviewers: reames, fhahn, mkazantsev, chandlerc, craig.topper, courbet
Reviewed By: courbet
Subscribers: miyuki, hiraditya, xbolva00, nikic, jfb, gchatelet, courbet, llvm-commits, mclow.lists
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61144
llvm-svn: 374662
Currently, it is hard for the compiler to remove unused C++ virtual
functions, because they are all referenced from vtables, which are referenced
by constructors. This means that if the constructor is called from any live
code, then we keep every virtual function in the final link, even if there
are no call sites which can use it.
This patch allows unused virtual functions to be removed during LTO (and
regular compilation in limited circumstances) by using type metadata to match
virtual function call sites to the vtable slots they might load from. This
information can then be used in the global dead code elimination pass instead
of the references from vtables to virtual functions, to more accurately
determine which functions are reachable.
To make this transformation safe, I have changed clang's code-generation to
always load virtual function pointers using the llvm.type.checked.load
intrinsic, instead of regular load instructions. I originally tried writing
this using clang's existing code-generation, which uses the llvm.type.test
and llvm.assume intrinsics after doing a normal load. However, it is possible
for optimisations to obscure the relationship between the GEP, load and
llvm.type.test, causing GlobalDCE to fail to find virtual function call
sites.
The existing linkage and visibility types don't accurately describe the scope
in which a virtual call could be made which uses a given vtable. This is
wider than the visibility of the type itself, because a virtual function call
could be made using a more-visible base class. I've added a new
!vcall_visibility metadata type to represent this, described in
TypeMetadata.rst. The internalization pass and libLTO have been updated to
change this metadata when linking is performed.
This doesn't currently work with ThinLTO, because it needs to see every call
to llvm.type.checked.load in the linkage unit. It might be possible to
extend this optimisation to be able to use the ThinLTO summary, as was done
for devirtualization, but until then that combination is rejected in the
clang driver.
To test this, I've written a fuzzer which generates random C++ programs with
complex class inheritance graphs, and virtual functions called through object
and function pointers of different types. The programs are spread across
multiple translation units and DSOs to test the different visibility
restrictions.
I've also tried doing bootstrap builds of LLVM to test this. This isn't
ideal, because only classes in anonymous namespaces can be optimised with
-fvisibility=default, and some parts of LLVM (plugins and bugpoint) do not
work correctly with -fvisibility=hidden. However, there are only 12 test
failures when building with -fvisibility=hidden (and an unmodified compiler),
and this change does not cause any new failures for either value of
-fvisibility.
On the 7 C++ sub-benchmarks of SPEC2006, this gives a geomean code-size
reduction of ~6%, over a baseline compiled with "-O2 -flto
-fvisibility=hidden -fwhole-program-vtables". The best cases are reductions
of ~14% in 450.soplex and 483.xalancbmk, and there are no code size
increases.
I've also run this on a set of 8 mbed-os examples compiled for Armv7M, which
show a geomean size reduction of ~3%, again with no size increases.
I had hoped that this would have no effect on performance, which would allow
it to awlays be enabled (when using -fwhole-program-vtables). However, the
changes in clang to use the llvm.type.checked.load intrinsic are causing ~1%
performance regression in the C++ parts of SPEC2006. It should be possible to
recover some of this perf loss by teaching optimisations about the
llvm.type.checked.load intrinsic, which would make it worth turning this on
by default (though it's still dependent on -fwhole-program-vtables).
Differential revision: https://reviews.llvm.org/D63932
llvm-svn: 374539
The FileCheck utility is enhanced to support a `--ignore-case`
option. This is useful in cases where the output of Unix tools
differs in case (e.g. case not specified by Posix).
Reviewers: Bigcheese, jakehehrlich, rupprecht, espindola, alexshap, jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D68146
llvm-svn: 374538
Bring back `--threads` option which was lost in the move of the
command line argument parsing code to cl_arguments.py. Update docs
since `--workers` is preferred.
llvm-svn: 374432
Summary:
Just realized that most of the links in this page are deprecated.
So update some important reference here:
* adding PowerISA 3.0B/2.7B
* adding P8/P9 User Manual
* ELFv2 ABI and errata
Move deprecated ones into "Other documents..".
Reviewers: #powerpc, hfinkel, nemanjai
Reviewed By: hfinkel
Subscribers: shchenz, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68817
llvm-svn: 374428
Summary:
As disscused in https://bugs.llvm.org/show_bug.cgi?id=43219,
i believe it may be somewhat useful to show //some// aggregates
over all the sea of statistics provided.
Example:
```
Average Wait times (based on the timeline view):
[0]: Executions
[1]: Average time spent waiting in a scheduler's queue
[2]: Average time spent waiting in a scheduler's queue while ready
[3]: Average time elapsed from WB until retire stage
[0] [1] [2] [3]
0. 3 1.0 1.0 4.7 vmulps %xmm0, %xmm1, %xmm2
1. 3 2.7 0.0 2.3 vhaddps %xmm2, %xmm2, %xmm3
2. 3 6.0 0.0 0.0 vhaddps %xmm3, %xmm3, %xmm4
3 3.2 0.3 2.3 <total>
```
I.e. we average the averages.
Reviewers: andreadb, mattd, RKSimon
Reviewed By: andreadb
Subscribers: gbedwell, arphaman, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68714
llvm-svn: 374361
The FileCheck utility is enhanced to support a `--ignore-case`
option. This is useful in cases where the output of Unix tools
differs in case (e.g. case not specified by Posix).
Reviewers: Bigcheese, jakehehrlich, rupprecht, espindola, alexshap, jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D68146
llvm-svn: 374339
Summary:
Quote from http://eel.is/c++draft/expr.add#4:
```
4 When an expression J that has integral type is added to or subtracted
from an expression P of pointer type, the result has the type of P.
(4.1) If P evaluates to a null pointer value and J evaluates to 0,
the result is a null pointer value.
(4.2) Otherwise, if P points to an array element i of an array object x with n
elements ([dcl.array]), the expressions P + J and J + P
(where J has the value j) point to the (possibly-hypothetical) array
element i+j of x if 0≤i+j≤n and the expression P - J points to the
(possibly-hypothetical) array element i−j of x if 0≤i−j≤n.
(4.3) Otherwise, the behavior is undefined.
```
Therefore, as per the standard, applying non-zero offset to `nullptr`
(or making non-`nullptr` a `nullptr`, by subtracting pointer's integral value
from the pointer itself) is undefined behavior. (*if* `nullptr` is not defined,
i.e. e.g. `-fno-delete-null-pointer-checks` was *not* specified.)
To make things more fun, in C (6.5.6p8), applying *any* offset to null pointer
is undefined, although Clang front-end pessimizes the code by not lowering
that info, so this UB is "harmless".
Since rL369789 (D66608 `[InstCombine] icmp eq/ne (gep inbounds P, Idx..), null -> icmp eq/ne P, null`)
LLVM middle-end uses those guarantees for transformations.
If the source contains such UB's, said code may now be miscompiled.
Such miscompilations were already observed:
* https://lists.llvm.org/pipermail/llvm-commits/Week-of-Mon-20190826/687838.html
* https://github.com/google/filament/pull/1566
Surprisingly, UBSan does not catch those issues
... until now. This diff teaches UBSan about these UB's.
`getelementpointer inbounds` is a pretty frequent instruction,
so this does have a measurable impact on performance;
I've addressed most of the obvious missing folds (and thus decreased the performance impact by ~5%),
and then re-performed some performance measurements using my [[ https://github.com/darktable-org/rawspeed | RawSpeed ]] benchmark:
(all measurements done with LLVM ToT, the sanitizer never fired.)
* no sanitization vs. existing check: average `+21.62%` slowdown
* existing check vs. check after this patch: average `22.04%` slowdown
* no sanitization vs. this patch: average `48.42%` slowdown
Reviewers: vsk, filcab, rsmith, aaron.ballman, vitalybuka, rjmccall, #sanitizers
Reviewed By: rsmith
Subscribers: kristof.beyls, nickdesaulniers, nikic, ychen, dtzWill, xbolva00, dberris, arphaman, rupprecht, reames, regehr, llvm-commits, cfe-commits
Tags: #clang, #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D67122
llvm-svn: 374293
Adds links to Getting Started/Tutorials, User Guides, and Reference documentation pages to sidebar. Also adds a new section for LLVM IR on the Reference documentation page.
llvm-svn: 374214
Summary:
This adds a `-max-configs-per-opcode` option to limit the number of
configs per opcode.
Reviewers: gchatelet
Subscribers: tschuett, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68642
llvm-svn: 374054
it just happened to break the bot right when I did my push. So I'm undoing
this mornings incorrect push. I've also kicked off an email to hopefully
get the bot fixed the correct way.
llvm-svn: 374049
When the target option GuaranteedTailCallOpt is specified, calls with
the fastcc calling convention will be transformed into tail calls if
they are in tail position. This diff adds a new calling convention,
tailcc, currently supported only on X86, which behaves the same way as
fastcc, except that the GuaranteedTailCallOpt flag does not need to
enabled in order to enable tail call optimization.
Patch by Dwight Guth <dwight.guth@runtimeverification.com>!
Reviewed By: lebedev.ri, paquette, rnk
Differential Revision: https://reviews.llvm.org/D67855
llvm-svn: 373976
Earlier in the year intrinsics for lrint, llrint, lround and llround were
added to llvm. The constrained versions are now implemented here.
Reviewed by: andrew.w.kaylor, craig.topper, cameron.mcinally
Approved by: craig.topper
Differential Revision: https://reviews.llvm.org/D64746
llvm-svn: 373900
Removes Programming Documentation page. Also moves existing topics on Programming Documentation page to User Guides and Reference pages.
llvm-svn: 373856
Fixes PR43181. This option was recently added to GNU objcopy (binutils
PR24942).
`llvm-objcopy -I binary -O elf64-x86-64 --set-section-alignment .data=8` can set the alignment of .data.
Reviewed By: grimar, jhenderson, rupprecht
Differential Revision: https://reviews.llvm.org/D67656
llvm-svn: 373461
The tool reports verbose output for the DWARF debug location coverage.
The llvm-locstats for each variable or formal parameter DIE computes what
percentage from the code section bytes, where it is in scope, it has
location description. The line 0 shows the number (and the percentage) of
DIEs with no location information, but the line 100 shows the number (and
the percentage) of DIEs where there is location information in all code
section bytes (where the variable or parameter is in the scope). The line
50..59 shows the number (and the percentage) of DIEs where the location
information is in between 50 and 59 percentage of its scope covered.
Differential Revision: https://reviews.llvm.org/D66526
The cause of the test failure was resolved.
llvm-svn: 373427
The tool reports verbose output for the DWARF debug location coverage.
The llvm-locstats for each variable or formal parameter DIE computes what
percentage from the code section bytes, where it is in scope, it has
location description. The line 0 shows the number (and the percentage) of
DIEs with no location information, but the line 100 shows the number (and
the percentage) of DIEs where there is location information in all code
section bytes (where the variable or parameter is in the scope). The line
50..59 shows the number (and the percentage) of DIEs where the location
information is in between 50 and 59 percentage of its scope covered.
Differential Revision: https://reviews.llvm.org/D66526
llvm-svn: 373317
D68110 added --arch-specific (supported by GNU readelf) and made
--arm-attributes an alias for it. The tests were later migrated to use
--arch-specific.
Note, llvm-readelf --arch-specific currently just uses llvm-readobj
style output for ARM attributes. The readelf-style output is not
implemented.
Reviewed By: compnerd, kongyi, rupprecht
Differential Revision: https://reviews.llvm.org/D68196
llvm-svn: 373291
Summary: The constraint goes up to regs d15 and q7, not d16 and q8.
Subscribers: kristof.beyls, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68090
llvm-svn: 373228
The tool reports verbose output for the DWARF debug location coverage.
The llvm-locstats for each variable or formal parameter DIE computes what
percentage from the code section bytes, where it is in scope, it has
location description. The line 0 shows the number (and the percentage) of
DIEs with no location information, but the line 100 shows the number (and
the percentage) of DIEs where there is location information in all code
section bytes (where the variable or parameter is in the scope). The line
50..59 shows the number (and the percentage) of DIEs where the location
information is in between 50 and 59 percentage of its scope covered.
Differential Revision: https://reviews.llvm.org/D66526
llvm-svn: 373183
Moves existing article links on the Programming, Subsystem, and Reference documentation pages to new locations. Also moves Github Repository and Publications links to the sidebar.
llvm-svn: 373169
Adds a section to the User Guides page for articles related to building, packaging, and distributing LLVM. Includes sub-sections for CMake, Clang, and Docker.
llvm-svn: 373113
Summary:
The list of indirect labels should ALWAYS have their blockaddresses as
argument operands to the callbr (but not necessarily the other way
around). Add an invariant that checks this.
The verifier catches a bad test case that was added recently in r368478.
I think that was a simple mistake, and the test was made less strict in
regards to the precise addresses (as those weren't specifically the
point of the test).
This invariant will be used to find a reported bug.
Link: https://www.spinics.net/lists/arm-kernel/msg753473.html
Link: https://github.com/ClangBuiltLinux/linux/issues/649
Reviewers: craig.topper, void, chandlerc
Reviewed By: void
Subscribers: ychen, lebedev.ri, javed.absar, kristof.beyls, hiraditya, llvm-commits, srhines
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67196
llvm-svn: 372923
During the review of D67434, it was recommended to make fmuladd's
behavior more explicit. D67434 depends on this interpretation.
Reviewers: efriedma, jfb, reames, scanon, lebedev.ri, spatel
Reviewed By: spatel
Differential Revision: https://reviews.llvm.org/D67552
llvm-svn: 372892
The changes here are based on the corresponding diffs for allowing FMF on 'select':
D61917 <https://reviews.llvm.org/D61917>
As discussed there, we want to have fast-math-flags be a property of an FP value
because the alternative (having them on things like fcmp) leads to logical
inconsistency such as:
https://bugs.llvm.org/show_bug.cgi?id=38086
The earlier patch for select made almost no practical difference because most
unoptimized conditional code begins life as a phi (based on what I see in clang).
Similarly, I don't expect this patch to do much on its own either because
SimplifyCFG promptly drops the flags when converting to select on a minimal
example like:
https://bugs.llvm.org/show_bug.cgi?id=39535
But once we have this plumbing in place, we should be able to wire up the FMF
propagation and start solving cases like that.
The change to RecurrenceDescriptor::AddReductionVar() is required to prevent a
regression in a LoopVectorize test. We are intersecting the FMF of any
FPMathOperator there, so if a phi is not properly annotated, new math
instructions may not be either. Once we fix the propagation in SimplifyCFG, it
may be safe to remove that hack.
Differential Revision: https://reviews.llvm.org/D67564
llvm-svn: 372878
The changes here are based on the corresponding diffs for allowing FMF on 'select':
D61917
As discussed there, we want to have fast-math-flags be a property of an FP value
because the alternative (having them on things like fcmp) leads to logical
inconsistency such as:
https://bugs.llvm.org/show_bug.cgi?id=38086
The earlier patch for select made almost no practical difference because most
unoptimized conditional code begins life as a phi (based on what I see in clang).
Similarly, I don't expect this patch to do much on its own either because
SimplifyCFG promptly drops the flags when converting to select on a minimal
example like:
https://bugs.llvm.org/show_bug.cgi?id=39535
But once we have this plumbing in place, we should be able to wire up the FMF
propagation and start solving cases like that.
The change to RecurrenceDescriptor::AddReductionVar() is required to prevent a
regression in a LoopVectorize test. We are intersecting the FMF of any
FPMathOperator there, so if a phi is not properly annotated, new math
instructions may not be either. Once we fix the propagation in SimplifyCFG, it
may be safe to remove that hack.
Differential Revision: https://reviews.llvm.org/D67564
llvm-svn: 372866
The --bytes option uses the phrase "printable ASCII characters", but the
description section used simply "printable characters". To avoid any
confusion about locale impacts etc, this change adopts the former's
phrasing in both places. It also fixes a minor grammar issue in the
description.
Reviewed by: MaskRay
Differential Revision: https://reviews.llvm.org/D68016
llvm-svn: 372865
Main changes are mostly wording of some options, but this change also
fixes a switch reference so that a link is created and moves
--strip-sections into the ELF-specific area since it is only supported
for ELF currently.
llvm-svn: 372864
The tool reports verbose output for the DWARF debug location coverage.
The llvm-locstats for each variable or formal parameter DIE computes what
percentage from the code section bytes, where it is in scope, it has
location description. The line 0 shows the number (and the percentage) of
DIEs with no location information, but the line 100 shows the number (and
the percentage) of DIEs where there is location information in all code
section bytes (where the variable or parameter is in the scope). The line
50..59 shows the number (and the percentage) of DIEs where the location
information is in between 50 and 59 percentage of its scope covered.
Differential Revision: https://reviews.llvm.org/D66526
llvm-svn: 372554
Adds a new page for existing Getting Involved, Development Process, and Community Proposals articles. Also moves Mailing Lists, Meetups and social events, and IRC sections.
llvm-svn: 372487
Adds additional links to sidebar. Also removes Glossary and FAQ from LLVM Design & Overview section. (These links now reside on the sidebar.)
llvm-svn: 372469
Adds a custom sidebar to LLVM docs. Sidebar includes links to How to submit a bug and FAQ topics, as well as a Show Source link and search box.
llvm-svn: 372432
Summary:
This is the first patch in a series of patches that will implement data dependence graph in LLVM. Many of the ideas used in this implementation are based on the following paper:
D. J. Kuck, R. H. Kuhn, D. A. Padua, B. Leasure, and M. Wolfe (1981). DEPENDENCE GRAPHS AND COMPILER OPTIMIZATIONS.
This patch contains support for a basic DDGs containing only atomic nodes (one node for each instruction). The edges are two fold: def-use edges and memory-dependence edges.
The implementation takes a list of basic-blocks and only considers dependencies among instructions in those basic blocks. Any dependencies coming into or going out of instructions that do not belong to those basic blocks are ignored.
The algorithm for building the graph involves the following steps in order:
1. For each instruction in the range of basic blocks to consider, create an atomic node in the resulting graph.
2. For each node in the graph establish def-use edges to/from other nodes in the graph.
3. For each pair of nodes containing memory instruction(s) create memory edges between them. This part of the algorithm goes through the instructions in lexicographical order and creates edges in reverse order if the sink of the dependence occurs before the source of it.
Authored By: bmahjour
Reviewer: Meinersbur, fhahn, myhsu, xtian, dmgreen, kbarton, jdoerfert
Reviewed By: Meinersbur, fhahn, myhsu
Subscribers: ychen, arphaman, simoll, a.elovikov, mgorny, hiraditya, jfb, wuzish, llvm-commits, jsji, Whitney, etiotto
Tag: #llvm
Differential Revision: https://reviews.llvm.org/D65350
llvm-svn: 372238
Fix the warning.
Bugpoint.rst:124:Mismatch: both interpreted text role prefix and
reference suffix.
Note that the line no here is wrong and misleading,
the problem is in line 128, not 124.
llvm-svn: 372181
Summary:
This is the first patch in a series of patches that will implement data dependence graph in LLVM. Many of the ideas used in this implementation are based on the following paper:
D. J. Kuck, R. H. Kuhn, D. A. Padua, B. Leasure, and M. Wolfe (1981). DEPENDENCE GRAPHS AND COMPILER OPTIMIZATIONS.
This patch contains support for a basic DDGs containing only atomic nodes (one node for each instruction). The edges are two fold: def-use edges and memory-dependence edges.
The implementation takes a list of basic-blocks and only considers dependencies among instructions in those basic blocks. Any dependencies coming into or going out of instructions that do not belong to those basic blocks are ignored.
The algorithm for building the graph involves the following steps in order:
1. For each instruction in the range of basic blocks to consider, create an atomic node in the resulting graph.
2. For each node in the graph establish def-use edges to/from other nodes in the graph.
3. For each pair of nodes containing memory instruction(s) create memory edges between them. This part of the algorithm goes through the instructions in lexicographical order and creates edges in reverse order if the sink of the dependence occurs before the source of it.
Authored By: bmahjour
Reviewer: Meinersbur, fhahn, myhsu, xtian, dmgreen, kbarton, jdoerfert
Reviewed By: Meinersbur, fhahn, myhsu
Subscribers: ychen, arphaman, simoll, a.elovikov, mgorny, hiraditya, jfb, wuzish, llvm-commits, jsji, Whitney, etiotto
Tag: #llvm
Differential Revision: https://reviews.llvm.org/D65350
llvm-svn: 372162
Summary:
When reducing case for a CodeGenCrash, bugpoint may generate a new
reduced
testcase that exposes/causes another crash or break something due to
limitation.
Bugpoint does not distiguish different crashes currently,
so when this happens, bugpoint will go on reducing for the new crash,
or just abort, we can't get the case reduced for the origial crash.
An advice is added into usage doc to connect to recommend checking error
message with scripts and `-compile-command`.
Reviewers: modocache, bogner, sebpop, reames, vsk, MatzeB
Reviewed By: vsk
Subscribers: mehdi_amini, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66832
llvm-svn: 372157
Follow-up to r371983. Referring to "this program" in the description of
the --version option in the documentation isn't exactly correct, because
the docs are not part of the program, and so "this program" doesn't
really refer to anything. This patch brings the other users of this
terminology into line with the new updates to llvm-size and
llvm-strings.
Reviewed by: alexshap, MaskRay
Differential Revision: https://reviews.llvm.org/D67618
llvm-svn: 372107
Previously we only had a stub document.
Reviewed by: serge-sans-paille, MaskRay
Differential Revision: https://reviews.llvm.org/D67555
llvm-svn: 371983
Summary:
Adds the following inline asm constraints for SVE:
- Upl: One of the low eight SVE predicate registers, P0 to P7 inclusive
- Upa: SVE predicate register with full range, P0 to P15
Reviewers: t.p.northover, sdesmalen, rovka, momchil.velikov, cameron.mcinally, greened, rengolin
Reviewed By: rovka
Subscribers: javed.absar, tschuett, rkruppe, psnobl, cfe-commits, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66524
llvm-svn: 371967
GNU objcopy documents that -B is only useful with architecture-less
input (i.e. "binary" or "ihex"). After D67144, -O defaults to -I, and
-B is essentially a NOP.
* If -O is binary/ihex, GNU objcopy ignores -B.
* If -O is elf*, -B provides the e_machine field in GNU objcopy.
So to convert a blob to an ELF, `-I binary -B i386:x86-64 -O elf64-x86-64` has to be specified.
`-I binary -B i386:x86-64 -O elf64-x86-64` creates an ELF with its
e_machine field set to EM_NONE in GNU objcopy, but a regular x86_64 ELF
in elftoolchain elfcopy. Follow the elftoolchain approach (ignoring -B)
to simplify code. Users that expect their command line portable should
specify -B.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D67215
llvm-svn: 371914
llvm-readobj's document was missing --stack-sizes entirely from its
document, so this patch adds it. It also adds a note to the llvm-readelf
description that the switch is only implemented for GNU style output
currently. For reference, --stack-sizes was added in r367942.
Reviewed by: MaskRay
Differential Revision: https://reviews.llvm.org/D67548
llvm-svn: 371862
Behaviour was recently added to this switch to strip debug sections too.
See r369761.
This change also makes the description for the --strip-unneeded switch
consistent between the two docs.
Reviewed by: MaskRay
Differential Revision: https://reviews.llvm.org/D67546
llvm-svn: 371855
AVX512 instructions can cause a frequency drop on these CPUs. This
can negate the performance gains from using wider vectors. Enabling
prefer-vector-width=256 will prevent generation of zmm registers
unless explicit 512 bit operations are used in the original source
code.
I believe gcc and icc both do something similar to this by default.
Differential Revision: https://reviews.llvm.org/D67259
llvm-svn: 371694
The tool reports verbose output for the DWARF debug location coverage.
The llvm-locstats for each variable or formal parameter DIE computes what
percentage from the code section bytes, where it is in scope, it has
location description. The line 0 shows the number (and the percentage) of
DIEs with no location information, but the line 100 shows the number (and
the percentage) of DIEs where there is location information in all code
section bytes (where the variable or parameter is in the scope). The line
50..59 shows the number (and the percentage) of DIEs where the location
information is in between 50 and 59 percentage of its scope covered.
The tool will be very useful for tracking improvements regarding the
"debugging optimized code" support with LLVM ecosystem.
Differential Revision: https://reviews.llvm.org/D66526
llvm-svn: 371520
Summary:
Add an intrinsic that takes 2 unsigned integers with
the scale of them provided as the third argument and
performs fixed point multiplication on them. The
result is saturated and clamped between the largest and
smallest representable values of the first 2 operands.
This is a part of implementing fixed point arithmetic
in clang where some of the more complex operations
will be implemented as intrinsics.
Patch by: leonardchan, bjope
Reviewers: RKSimon, craig.topper, bevinh, leonardchan, lebedev.ri, spatel
Reviewed By: leonardchan
Subscribers: ychen, wuzish, nemanjai, MaskRay, jsji, jdoerfert, Ka-Ka, hiraditya, rjmccall, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57836
llvm-svn: 371308
This commit includes the following changes: Adds a Getting Involved section under Community. Moves the Development Process section under Community. Moves Sphinx Quickstart Template and How to submit an LLVM bug report from User Guides section to Getting Involved.
llvm-svn: 371127
Updates the links on the homepage by moving the User Guides, Programming Documentation, and Subsystem Documentation sections to separate pages. Also changes "Overview" to "About" at the top of the LLVM Docs homepage. This work is part of the Google Season of Docs project.
llvm-svn: 371096
Summary:
This patch renames functions that takes or returns alignment as log2, this patch will help with the transition to llvm::Align.
The renaming makes it explicit that we deal with log(alignment) instead of a power of two alignment.
A few renames uncovered dubious assignments:
- `MirParser`/`MirPrinter` was expecting powers of two but `MachineFunction` and `MachineBasicBlock` were using deal with log2(align). This patch fixes it and updates the documentation.
- `MachineBlockPlacement` exposes two flags (`align-all-blocks` and `align-all-nofallthru-blocks`) supposedly interpreted as power of two alignments, internally these values are interpreted as log2(align). This patch updates the documentation,
- `MachineFunctionexposes` exposes `align-all-functions` also interpreted as power of two alignment, internally this value is interpreted as log2(align). This patch updates the documentation,
Reviewers: lattner, thegameg, courbet
Subscribers: dschuff, arsenm, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, javed.absar, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, Jim, s.egerton, llvm-commits, courbet
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65945
llvm-svn: 371045
Add a mode in which profile read errors are not immediately treated as
fatal. In this mode, merging makes forward progress and reports failure
only if no inputs can be read.
Differential Revision: https://reviews.llvm.org/D66985
llvm-svn: 370827
Summary:
Adds the following inline asm constraints for SVE:
- w: SVE vector register with full range, Z0 to Z31
- x: Restricted to registers Z0 to Z15 inclusive.
- y: Restricted to registers Z0 to Z7 inclusive.
This change also adds the "z" modifier to interpret a register as an SVE register.
Not all of the bitconvert patterns added by this patch are used, but they have been included here for completeness.
Reviewers: t.p.northover, sdesmalen, rovka, momchil.velikov, rengolin, cameron.mcinally, greened
Reviewed By: sdesmalen
Subscribers: javed.absar, tschuett, rkruppe, psnobl, cfe-commits, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66302
llvm-svn: 370673
Summary:
Commit r366897 introduced the possibility to set a variable from an
expression, such as [[#VAR2:VAR1+3]]. While introducing this feature, it
introduced extra logic to allow using such a variable on the same line
later on. Unfortunately that extra logic is flawed as it relies on a
mapping from variable to expression defining it when the mapping is from
variable definition to expression. This flaw causes among other issues
PR42896.
This commit avoids the problem by forbidding all use of a variable
defined on the same line, and removes the now useless logic. Redesign
will be done in a later commit because it will require some amount of
refactoring first for the solution to be clean. One example is the need
for some sort of transaction mechanism to set a variable temporarily and
from an expression and rollback if the CHECK pattern does not match so
that diagnostics show the right variable values.
Reviewers: jhenderson, chandlerc, jdenny, probinson, grimar, arichardson, rnk
Subscribers: JonChesterfield, rogfer01, hfinkel, kristina, rnk, tra, arichardson, grimar, dblaikie, probinson, llvm-commits, hiraditya
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66141
llvm-svn: 370663
Some saturation examples for llvm.smul.fix.sat were not showing
the correct result. I've adjusted the operands to make sure that
we actually trigger overflow in those examples.
llvm-svn: 370566
gcc and icc pass these types in zmm registers in zmm registers.
This patch implements a quick hack to override the register
type before calling convention handling to one that is legal.
Longer term we might want to do something similar to 256-bit
integer registers on AVX1 where we just split all the operations.
Fixes PR42957
Differential Revision: https://reviews.llvm.org/D66708
llvm-svn: 370495
Summary:
@mclow.lists brought up this issue up in IRC.
It is a reasonably common problem to compare some two values for equality.
Those may be just some integers, strings or arrays of integers.
In C, there is `memcmp()`, `bcmp()` functions.
In C++, there exists `std::equal()` algorithm.
One can also write that function manually.
libstdc++'s `std::equal()` is specialized to directly call `memcmp()` for
various types, but not `std::byte` from C++2a. https://godbolt.org/z/mx2ejJ
libc++ does not do anything like that, it simply relies on simple C++'s
`operator==()`. https://godbolt.org/z/er0Zwf (GOOD!)
So likely, there exists a certain performance opportunities.
Let's compare performance of naive `std::equal()` (no `memcmp()`) with one that
is using `memcmp()` (in this case, compiled with modified compiler). {F8768213}
```
#include <algorithm>
#include <cmath>
#include <cstdint>
#include <iterator>
#include <limits>
#include <random>
#include <type_traits>
#include <utility>
#include <vector>
#include "benchmark/benchmark.h"
template <class T>
bool equal(T* a, T* a_end, T* b) noexcept {
for (; a != a_end; ++a, ++b) {
if (*a != *b) return false;
}
return true;
}
template <typename T>
std::vector<T> getVectorOfRandomNumbers(size_t count) {
std::random_device rd;
std::mt19937 gen(rd());
std::uniform_int_distribution<T> dis(std::numeric_limits<T>::min(),
std::numeric_limits<T>::max());
std::vector<T> v;
v.reserve(count);
std::generate_n(std::back_inserter(v), count,
[&dis, &gen]() { return dis(gen); });
assert(v.size() == count);
return v;
}
struct Identical {
template <typename T>
static std::pair<std::vector<T>, std::vector<T>> Gen(size_t count) {
auto Tmp = getVectorOfRandomNumbers<T>(count);
return std::make_pair(Tmp, std::move(Tmp));
}
};
struct InequalHalfway {
template <typename T>
static std::pair<std::vector<T>, std::vector<T>> Gen(size_t count) {
auto V0 = getVectorOfRandomNumbers<T>(count);
auto V1 = V0;
V1[V1.size() / size_t(2)]++; // just change the value.
return std::make_pair(std::move(V0), std::move(V1));
}
};
template <class T, class Gen>
void BM_bcmp(benchmark::State& state) {
const size_t Length = state.range(0);
const std::pair<std::vector<T>, std::vector<T>> Data =
Gen::template Gen<T>(Length);
const std::vector<T>& a = Data.first;
const std::vector<T>& b = Data.second;
assert(a.size() == Length && b.size() == a.size());
benchmark::ClobberMemory();
benchmark::DoNotOptimize(a);
benchmark::DoNotOptimize(a.data());
benchmark::DoNotOptimize(b);
benchmark::DoNotOptimize(b.data());
for (auto _ : state) {
const bool is_equal = equal(a.data(), a.data() + a.size(), b.data());
benchmark::DoNotOptimize(is_equal);
}
state.SetComplexityN(Length);
state.counters["eltcnt"] =
benchmark::Counter(Length, benchmark::Counter::kIsIterationInvariant);
state.counters["eltcnt/sec"] =
benchmark::Counter(Length, benchmark::Counter::kIsIterationInvariantRate);
const size_t BytesRead = 2 * sizeof(T) * Length;
state.counters["bytes_read/iteration"] =
benchmark::Counter(BytesRead, benchmark::Counter::kDefaults,
benchmark::Counter::OneK::kIs1024);
state.counters["bytes_read/sec"] = benchmark::Counter(
BytesRead, benchmark::Counter::kIsIterationInvariantRate,
benchmark::Counter::OneK::kIs1024);
}
template <typename T>
static void CustomArguments(benchmark::internal::Benchmark* b) {
const size_t L2SizeBytes = []() {
for (const benchmark::CPUInfo::CacheInfo& I :
benchmark::CPUInfo::Get().caches) {
if (I.level == 2) return I.size;
}
return 0;
}();
// What is the largest range we can check to always fit within given L2 cache?
const size_t MaxLen = L2SizeBytes / /*total bufs*/ 2 /
/*maximal elt size*/ sizeof(T) / /*safety margin*/ 2;
b->RangeMultiplier(2)->Range(1, MaxLen)->Complexity(benchmark::oN);
}
BENCHMARK_TEMPLATE(BM_bcmp, uint8_t, Identical)
->Apply(CustomArguments<uint8_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint16_t, Identical)
->Apply(CustomArguments<uint16_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint32_t, Identical)
->Apply(CustomArguments<uint32_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint64_t, Identical)
->Apply(CustomArguments<uint64_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint8_t, InequalHalfway)
->Apply(CustomArguments<uint8_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint16_t, InequalHalfway)
->Apply(CustomArguments<uint16_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint32_t, InequalHalfway)
->Apply(CustomArguments<uint32_t>);
BENCHMARK_TEMPLATE(BM_bcmp, uint64_t, InequalHalfway)
->Apply(CustomArguments<uint64_t>);
```
{F8768210}
```
$ ~/src/googlebenchmark/tools/compare.py --no-utest benchmarks build-{old,new}/test/llvm-bcmp-bench
RUNNING: build-old/test/llvm-bcmp-bench --benchmark_out=/tmp/tmpb6PEUx
2019-04-25 21:17:11
Running build-old/test/llvm-bcmp-bench
Run on (8 X 4000 MHz CPU s)
CPU Caches:
L1 Data 16K (x8)
L1 Instruction 64K (x4)
L2 Unified 2048K (x4)
L3 Unified 8192K (x1)
Load Average: 0.65, 3.90, 4.14
---------------------------------------------------------------------------------------------------
Benchmark Time CPU Iterations UserCounters...
---------------------------------------------------------------------------------------------------
<...>
BM_bcmp<uint8_t, Identical>/512000 432131 ns 432101 ns 1613 bytes_read/iteration=1000k bytes_read/sec=2.20706G/s eltcnt=825.856M eltcnt/sec=1.18491G/s
BM_bcmp<uint8_t, Identical>_BigO 0.86 N 0.86 N
BM_bcmp<uint8_t, Identical>_RMS 8 % 8 %
<...>
BM_bcmp<uint16_t, Identical>/256000 161408 ns 161409 ns 4027 bytes_read/iteration=1000k bytes_read/sec=5.90843G/s eltcnt=1030.91M eltcnt/sec=1.58603G/s
BM_bcmp<uint16_t, Identical>_BigO 0.67 N 0.67 N
BM_bcmp<uint16_t, Identical>_RMS 25 % 25 %
<...>
BM_bcmp<uint32_t, Identical>/128000 81497 ns 81488 ns 8415 bytes_read/iteration=1000k bytes_read/sec=11.7032G/s eltcnt=1077.12M eltcnt/sec=1.57078G/s
BM_bcmp<uint32_t, Identical>_BigO 0.71 N 0.71 N
BM_bcmp<uint32_t, Identical>_RMS 42 % 42 %
<...>
BM_bcmp<uint64_t, Identical>/64000 50138 ns 50138 ns 10909 bytes_read/iteration=1000k bytes_read/sec=19.0209G/s eltcnt=698.176M eltcnt/sec=1.27647G/s
BM_bcmp<uint64_t, Identical>_BigO 0.84 N 0.84 N
BM_bcmp<uint64_t, Identical>_RMS 27 % 27 %
<...>
BM_bcmp<uint8_t, InequalHalfway>/512000 192405 ns 192392 ns 3638 bytes_read/iteration=1000k bytes_read/sec=4.95694G/s eltcnt=1.86266G eltcnt/sec=2.66124G/s
BM_bcmp<uint8_t, InequalHalfway>_BigO 0.38 N 0.38 N
BM_bcmp<uint8_t, InequalHalfway>_RMS 3 % 3 %
<...>
BM_bcmp<uint16_t, InequalHalfway>/256000 127858 ns 127860 ns 5477 bytes_read/iteration=1000k bytes_read/sec=7.45873G/s eltcnt=1.40211G eltcnt/sec=2.00219G/s
BM_bcmp<uint16_t, InequalHalfway>_BigO 0.50 N 0.50 N
BM_bcmp<uint16_t, InequalHalfway>_RMS 0 % 0 %
<...>
BM_bcmp<uint32_t, InequalHalfway>/128000 49140 ns 49140 ns 14281 bytes_read/iteration=1000k bytes_read/sec=19.4072G/s eltcnt=1.82797G eltcnt/sec=2.60478G/s
BM_bcmp<uint32_t, InequalHalfway>_BigO 0.40 N 0.40 N
BM_bcmp<uint32_t, InequalHalfway>_RMS 18 % 18 %
<...>
BM_bcmp<uint64_t, InequalHalfway>/64000 32101 ns 32099 ns 21786 bytes_read/iteration=1000k bytes_read/sec=29.7101G/s eltcnt=1.3943G eltcnt/sec=1.99381G/s
BM_bcmp<uint64_t, InequalHalfway>_BigO 0.50 N 0.50 N
BM_bcmp<uint64_t, InequalHalfway>_RMS 1 % 1 %
RUNNING: build-new/test/llvm-bcmp-bench --benchmark_out=/tmp/tmpQ46PP0
2019-04-25 21:19:29
Running build-new/test/llvm-bcmp-bench
Run on (8 X 4000 MHz CPU s)
CPU Caches:
L1 Data 16K (x8)
L1 Instruction 64K (x4)
L2 Unified 2048K (x4)
L3 Unified 8192K (x1)
Load Average: 1.01, 2.85, 3.71
---------------------------------------------------------------------------------------------------
Benchmark Time CPU Iterations UserCounters...
---------------------------------------------------------------------------------------------------
<...>
BM_bcmp<uint8_t, Identical>/512000 18593 ns 18590 ns 37565 bytes_read/iteration=1000k bytes_read/sec=51.2991G/s eltcnt=19.2333G eltcnt/sec=27.541G/s
BM_bcmp<uint8_t, Identical>_BigO 0.04 N 0.04 N
BM_bcmp<uint8_t, Identical>_RMS 37 % 37 %
<...>
BM_bcmp<uint16_t, Identical>/256000 18950 ns 18948 ns 37223 bytes_read/iteration=1000k bytes_read/sec=50.3324G/s eltcnt=9.52909G eltcnt/sec=13.511G/s
BM_bcmp<uint16_t, Identical>_BigO 0.08 N 0.08 N
BM_bcmp<uint16_t, Identical>_RMS 34 % 34 %
<...>
BM_bcmp<uint32_t, Identical>/128000 18627 ns 18627 ns 37895 bytes_read/iteration=1000k bytes_read/sec=51.198G/s eltcnt=4.85056G eltcnt/sec=6.87168G/s
BM_bcmp<uint32_t, Identical>_BigO 0.16 N 0.16 N
BM_bcmp<uint32_t, Identical>_RMS 35 % 35 %
<...>
BM_bcmp<uint64_t, Identical>/64000 18855 ns 18855 ns 37458 bytes_read/iteration=1000k bytes_read/sec=50.5791G/s eltcnt=2.39731G eltcnt/sec=3.3943G/s
BM_bcmp<uint64_t, Identical>_BigO 0.32 N 0.32 N
BM_bcmp<uint64_t, Identical>_RMS 33 % 33 %
<...>
BM_bcmp<uint8_t, InequalHalfway>/512000 9570 ns 9569 ns 73500 bytes_read/iteration=1000k bytes_read/sec=99.6601G/s eltcnt=37.632G eltcnt/sec=53.5046G/s
BM_bcmp<uint8_t, InequalHalfway>_BigO 0.02 N 0.02 N
BM_bcmp<uint8_t, InequalHalfway>_RMS 29 % 29 %
<...>
BM_bcmp<uint16_t, InequalHalfway>/256000 9547 ns 9547 ns 74343 bytes_read/iteration=1000k bytes_read/sec=99.8971G/s eltcnt=19.0318G eltcnt/sec=26.8159G/s
BM_bcmp<uint16_t, InequalHalfway>_BigO 0.04 N 0.04 N
BM_bcmp<uint16_t, InequalHalfway>_RMS 29 % 29 %
<...>
BM_bcmp<uint32_t, InequalHalfway>/128000 9396 ns 9394 ns 73521 bytes_read/iteration=1000k bytes_read/sec=101.518G/s eltcnt=9.41069G eltcnt/sec=13.6255G/s
BM_bcmp<uint32_t, InequalHalfway>_BigO 0.08 N 0.08 N
BM_bcmp<uint32_t, InequalHalfway>_RMS 30 % 30 %
<...>
BM_bcmp<uint64_t, InequalHalfway>/64000 9499 ns 9498 ns 73802 bytes_read/iteration=1000k bytes_read/sec=100.405G/s eltcnt=4.72333G eltcnt/sec=6.73808G/s
BM_bcmp<uint64_t, InequalHalfway>_BigO 0.16 N 0.16 N
BM_bcmp<uint64_t, InequalHalfway>_RMS 28 % 28 %
Comparing build-old/test/llvm-bcmp-bench to build-new/test/llvm-bcmp-bench
Benchmark Time CPU Time Old Time New CPU Old CPU New
---------------------------------------------------------------------------------------------------------------------------------------
<...>
BM_bcmp<uint8_t, Identical>/512000 -0.9570 -0.9570 432131 18593 432101 18590
<...>
BM_bcmp<uint16_t, Identical>/256000 -0.8826 -0.8826 161408 18950 161409 18948
<...>
BM_bcmp<uint32_t, Identical>/128000 -0.7714 -0.7714 81497 18627 81488 18627
<...>
BM_bcmp<uint64_t, Identical>/64000 -0.6239 -0.6239 50138 18855 50138 18855
<...>
BM_bcmp<uint8_t, InequalHalfway>/512000 -0.9503 -0.9503 192405 9570 192392 9569
<...>
BM_bcmp<uint16_t, InequalHalfway>/256000 -0.9253 -0.9253 127858 9547 127860 9547
<...>
BM_bcmp<uint32_t, InequalHalfway>/128000 -0.8088 -0.8088 49140 9396 49140 9394
<...>
BM_bcmp<uint64_t, InequalHalfway>/64000 -0.7041 -0.7041 32101 9499 32099 9498
```
What can we tell from the benchmark?
* Performance of naive equality check somewhat improves with element size,
maxing out at eltcnt/sec=1.58603G/s for uint16_t, or bytes_read/sec=19.0209G/s
for uint64_t. I think, that instability implies performance problems.
* Performance of `memcmp()`-aware benchmark always maxes out at around
bytes_read/sec=51.2991G/s for every type. That is 2.6x the throughput of the
naive variant!
* eltcnt/sec metric for the `memcmp()`-aware benchmark maxes out at
eltcnt/sec=27.541G/s for uint8_t (was: eltcnt/sec=1.18491G/s, so 24x) and
linearly decreases with element size.
For uint64_t, it's ~4x+ the elements/second.
* The call obvious is more pricey than the loop, with small element count.
As it can be seen from the full output {F8768210}, the `memcmp()` is almost
universally worse, independent of the element size (and thus buffer size) when
element count is less than 8.
So all in all, bcmp idiom does indeed pose untapped performance headroom.
This diff does implement said idiom recognition. I think a reasonable test
coverage is present, but do tell if there is anything obvious missing.
Now, quality. This does succeed to build and pass the test-suite, at least
without any non-bundled elements. {F8768216} {F8768217}
This transform fires 91 times:
```
$ /build/test-suite/utils/compare.py -m loop-idiom.NumBCmp result-new.json
Tests: 1149
Metric: loop-idiom.NumBCmp
Program result-new
MultiSourc...Benchmarks/7zip/7zip-benchmark 79.00
MultiSource/Applications/d/make_dparser 3.00
SingleSource/UnitTests/vla 2.00
MultiSource/Applications/Burg/burg 1.00
MultiSourc.../Applications/JM/lencod/lencod 1.00
MultiSource/Applications/lemon/lemon 1.00
MultiSource/Benchmarks/Bullet/bullet 1.00
MultiSourc...e/Benchmarks/MallocBench/gs/gs 1.00
MultiSourc...gs-C/TimberWolfMC/timberwolfmc 1.00
MultiSourc...Prolangs-C/simulator/simulator 1.00
```
The size changes are:
I'm not sure what's going on with SingleSource/UnitTests/vla.test yet, did not look.
```
$ /build/test-suite/utils/compare.py -m size..text result-{old,new}.json --filter-hash
Tests: 1149
Same hash: 907 (filtered out)
Remaining: 242
Metric: size..text
Program result-old result-new diff
test-suite...ingleSource/UnitTests/vla.test 753.00 833.00 10.6%
test-suite...marks/7zip/7zip-benchmark.test 1001697.00 966657.00 -3.5%
test-suite...ngs-C/simulator/simulator.test 32369.00 32321.00 -0.1%
test-suite...plications/d/make_dparser.test 89585.00 89505.00 -0.1%
test-suite...ce/Applications/Burg/burg.test 40817.00 40785.00 -0.1%
test-suite.../Applications/lemon/lemon.test 47281.00 47249.00 -0.1%
test-suite...TimberWolfMC/timberwolfmc.test 250065.00 250113.00 0.0%
test-suite...chmarks/MallocBench/gs/gs.test 149889.00 149873.00 -0.0%
test-suite...ications/JM/lencod/lencod.test 769585.00 769569.00 -0.0%
test-suite.../Benchmarks/Bullet/bullet.test 770049.00 770049.00 0.0%
test-suite...HMARK_ANISTROPIC_DIFFUSION/128 NaN NaN nan%
test-suite...HMARK_ANISTROPIC_DIFFUSION/256 NaN NaN nan%
test-suite...CHMARK_ANISTROPIC_DIFFUSION/64 NaN NaN nan%
test-suite...CHMARK_ANISTROPIC_DIFFUSION/32 NaN NaN nan%
test-suite...ENCHMARK_BILATERAL_FILTER/64/4 NaN NaN nan%
Geomean difference nan%
result-old result-new diff
count 1.000000e+01 10.00000 10.000000
mean 3.152090e+05 311695.40000 0.006749
std 3.790398e+05 372091.42232 0.036605
min 7.530000e+02 833.00000 -0.034981
25% 4.243300e+04 42401.00000 -0.000866
50% 1.197370e+05 119689.00000 -0.000392
75% 6.397050e+05 639705.00000 -0.000005
max 1.001697e+06 966657.00000 0.106242
```
I don't have timings though.
And now to the code. The basic idea is to completely replace the whole loop.
If we can't fully kill it, don't transform.
I have left one or two comments in the code, so hopefully it can be understood.
Also, there is a few TODO's that i have left for follow-ups:
* widening of `memcmp()`/`bcmp()`
* step smaller than the comparison size
* Metadata propagation
* more than two blocks as long as there is still a single backedge?
* ???
Reviewers: reames, fhahn, mkazantsev, chandlerc, craig.topper, courbet
Reviewed By: courbet
Subscribers: hiraditya, xbolva00, nikic, jfb, gchatelet, courbet, llvm-commits, mclow.lists
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61144
llvm-svn: 370454
-Deprecate -mmpx and -mno-mpx command line options
-Remove CPUID detection of mpx for -march=native
-Remove MPX from all CPUs
-Remove MPX preprocessor define
I've left the "mpx" string in the backend so we don't fail on old IR, but its not connected to anything.
gcc has also deprecated these command line options. https://www.phoronix.com/scan.php?page=news_item&px=GCC-Patch-To-Drop-MPX
Differential Revision: https://reviews.llvm.org/D66669
llvm-svn: 370393
This implements constrained floating point intrinsics for FP to signed and
unsigned integers.
Quoting from D32319:
The purpose of the constrained intrinsics is to force the optimizer to
respect the restrictions that will be necessary to support things like the
STDC FENV_ACCESS ON pragma without interfering with optimizations when
these restrictions are not needed.
Reviewed by: Andrew Kaylor, Craig Topper, Hal Finkel, Cameron McInally, Roman Lebedev, Kit Barton
Approved by: Craig Topper
Differential Revision: http://reviews.llvm.org/D63782
llvm-svn: 370228
This implements the DWARF 5 feature described in:
http://dwarfstd.org/ShowIssue.php?issue=141212.1
To support recognizing anonymous structs:
struct A {
struct { // Anonymous struct
int y;
};
} a;
This patch adds a new (DI)flag to LLVM metadata:
ExportSymbols
Differential Revision: https://reviews.llvm.org/D66352
llvm-svn: 369781
It was causing some errors like:
Encoding error:
'ascii' codec can't decode byte 0xe2 in position 341: ordinal not in range(128)
The full traceback has been saved in /tmp/sphinx-err-y2fq4dtb.log, if you want to report the issue to the developers.
llvm-svn: 369644
Summary:
Linking between markdown and rst files is currently not supported very well, e.g. the current llvm-addr2line docs [1] link to "llvm-symbolizer" instead of "llvm-symbolizer.html". This is weirdly broken in different ways depending on which versions of sphinx and recommonmark are being used, so workaround the bug by using rst everywhere.
[1] http://llvm.org/docs/CommandGuide/llvm-addr2line.html
Reviewers: jhenderson
Reviewed By: jhenderson
Subscribers: lebedev.ri, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66305
llvm-svn: 369553
Summary:
Note: Do not submit this documentation until Scudo support is reviewed and submitted (should be #[5]).
See D60593 for further information.
This patch introduces the public-facing documentation for GWP-ASan, as well as updating the definition of one of the options, which wasn't properly merged. The document describes the design and features of GWP-ASan, as well as how to use GWP-ASan from both a user's standpoint, and development documentation for supporting allocators.
Reviewers: jfb, morehouse, vlad.tsyrklevich
Reviewed By: morehouse, vlad.tsyrklevich
Subscribers: kcc, dexonsmith, kubamracek, cryptoad, jfb, #sanitizers, llvm-commits, vlad.tsyrklevich, morehouse
Tags: #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D62875
llvm-svn: 369552
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
llvm-svn: 369013
This patch adds a ptrmask intrinsic which allows masking out bits of a
pointer that must be zero when accessing it, because of ABI alignment
requirements or a restriction of the meaningful bits of a pointer
through the data layout.
This avoids doing a ptrtoint/inttoptr round trip in some cases (e.g. tagged
pointers) and allows us to not lose information about the underlying
object.
Reviewers: nlopes, efriedma, hfinkel, sanjoy, jdoerfert, aqjune
Reviewed by: sanjoy, jdoerfert
Differential Revision: https://reviews.llvm.org/D59065
llvm-svn: 368986
It is sometimes useful to have the C++ standard library linked into the
assembly when compiling clang, particularly when distributing a compiler
onto systems that don't have a copy of stdlibc++ or libc++ installed.
This functionality should work with either GCC or Clang as the host
compiler, though statically linking libc++ (as may be required for
licensing purposes) is only possible if the host compiler is Clang with
a copy of libc++ available.
Differential Revision: https://reviews.llvm.org/D65603
llvm-svn: 368907
Summary:
Back in January I changed the minimum toolchain version required to build clang
and LLVM: D57264. Since then we've release LLVM 8, following
[our process](http://llvm.org/docs/DeveloperPolicy.html#toolchain)
it's therefore now a good time to remove the soft-error and officially deprecate
older toolchains. I tried this out last Tursday night to see if any bots
complained, and I saw no complaints. I also manually audited bots and didn't see
any bot that should break, but their toolchain information is unreliable and
some bots are offline.
Once this patch stick we'll move to C++14 as we've
[already agreed](http://lists.llvm.org/pipermail/llvm-dev/2019-January/129452.html).
Subscribers: mgorny, jkorous, dexonsmith, llvm-commits, EricWF, thakis, chandlerc
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66188
llvm-svn: 368799
A quick contrast of this ABI with the currently-implemented ABI:
- Allocation is implicitly managed by the lowering passes, which is fine
for frontends that are fine with assuming that allocation cannot fail.
This assumption is necessary to implement dynamic allocas anyway.
- The lowering attempts to fit the coroutine frame into an opaque,
statically-sized buffer before falling back on allocation; the same
buffer must be provided to every resume point. A buffer must be at
least pointer-sized.
- The resume and destroy functions have been combined; the continuation
function takes a parameter indicating whether it has succeeded.
- Conversely, every suspend point begins its own continuation function.
- The continuation function pointer is directly returned to the caller
instead of being stored in the frame. The continuation can therefore
directly destroy the frame when exiting the coroutine instead of having
to leave it in a defunct state.
- Other values can be returned directly to the caller instead of going
through a promise allocation. The frontend provides a "prototype"
function declaration from which the type, calling convention, and
attributes of the continuation functions are taken.
- On the caller side, the frontend can generate natural IR that directly
uses the continuation functions as long as it prevents IPO with the
coroutine until lowering has happened. In combination with the point
above, the frontend is almost totally in charge of the ABI of the
coroutine.
- Unique-yield coroutines are given some special treatment.
llvm-svn: 368788
Flag -show-encoding enables the printing of instruction encodings as part of the
the instruction info view.
Example (with flags -mtriple=x86_64-- -mcpu=btver2):
Instruction Info:
[1]: #uOps
[2]: Latency
[3]: RThroughput
[4]: MayLoad
[5]: MayStore
[6]: HasSideEffects (U)
[7]: Encoding Size
[1] [2] [3] [4] [5] [6] [7] Encodings: Instructions:
1 2 1.00 4 c5 f0 59 d0 vmulps %xmm0, %xmm1, %xmm2
1 4 1.00 4 c5 eb 7c da vhaddps %xmm2, %xmm2, %xmm3
1 4 1.00 4 c5 e3 7c e3 vhaddps %xmm3, %xmm3, %xmm4
In this example, column Encoding Size is the size in bytes of the instruction
encoding. Column Encodings reports the actual instruction encodings as byte
sequences in hex (objdump style).
The computation of encodings is done by a utility class named mca::CodeEmitter.
In future, I plan to expose the CodeEmitter to the instruction builder, so that
information about instruction encoding sizes can be used by the simulator. That
would be a first step towards simulating the throughput from the decoders in the
hardware frontend.
Differential Revision: https://reviews.llvm.org/D65948
llvm-svn: 368432
Summary:
There aren't very many requirements on the legalization rules but we should
document them.
Reviewers: aditya_nandakumar, volkan, bogner, paquette, aemerson, rovka, arsenm, Petar.Avramovic
Subscribers: wdng, kristof.beyls, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62423
# Conflicts:
# llvm/docs/GlobalISel.rst
llvm-svn: 368321
For some targets the LICM pass can result in sub-optimal code in some
cases where it would be better not to run the pass, but it isn't
always possible to suppress the transformations heuristically.
Where the front-end has insight into such cases it is beneficial
to attach loop metadata to disable the pass - this change adds the
llvm.licm.disable metadata to enable that.
Differential Revision: https://reviews.llvm.org/D64557
llvm-svn: 368296
Summary:
The information for -info -thin -create -replace and -segalign flags are added to llvm-lipo.rst
Test Plan:
Reviewers: smeenai, alexshap, compnerd, mtrent
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65676
llvm-svn: 368235
This reverts commits:
"Added Delta IR Reduction Tool"
"[Bugpoint redesign] Added Pass to Remove Global Variables"
"Added Tool as Dependency to tests & fixed warnings"
Reduce/remove-funcs.ll is failing on bots.
llvm-svn: 368122
A function is "no-return" if we never reach a return instruction, either
because there are none or the ones that exist are dead.
Test have been adjusted:
- either noreturn was added, or
- noreturn was avoided by modifying the code.
The new noreturn_{sync,async} test make sure we do handle invoke
instructions with a noreturn (and potentially nowunwind) callee
correctly, even in the presence of potential asynchronous exceptions.
llvm-svn: 367948
This has come up twice already (once in pr42763 and once in the commit thread), so give warning of a new way in which UB can result in unexpected program behavior.
llvm-svn: 367941
For consistency with normal instructions and clarity when reading IR,
it's best to print the %0, %1, ... names of function arguments in
definitions.
Also modifies the parser to accept IR in that form for obvious reasons.
llvm-svn: 367755
Previously, debuginfo types are annotated to
IR builtin preserve_struct_access_index() and
preserve_union_access_index(), but not
preserve_array_access_index(). The debug info
is useful to identify the root type name which
later will be used for type comparison.
For user access without explicit type conversions,
the previous scheme works as we can ignore intermediate
compiler generated type conversions (e.g., from union types to
union members) and still generate correct access index string.
The issue comes with user explicit type conversions, e.g.,
converting an array to a structure like below:
struct t { int a; char b[40]; };
struct p { int c; int d; };
struct t *var = ...;
... __builtin_preserve_access_index(&(((struct p *)&(var->b[0]))->d)) ...
Although BPF backend can derive the type of &(var->b[0]),
explicit type annotation make checking more consistent
and less error prone.
Another benefit is for multiple dimension array handling.
For example,
struct p { int c; int d; } g[8][9][10];
... __builtin_preserve_access_index(&g[2][3][4].d) ...
It would be possible to calculate the number of "struct p"'s
before accessing its member "d" if array debug info is
available as it contains each dimension range.
This patch enables to annotate IR builtin preserve_array_access_index()
with proper debuginfo type. The unit test case and language reference
is updated as well.
Signed-off-by: Yonghong Song <yhs@fb.com>
Differential Revision: https://reviews.llvm.org/D65664
llvm-svn: 367724
ThreadSafeModule/ThreadSafeContext are used to manage lifetimes and locking
for LLVMContexts in ORCv2. Prior to this patch contexts were locked as soon
as an associated Module was emitted (to be compiled and linked), and were not
unlocked until the emit call returned. This could lead to deadlocks if
interdependent modules that shared contexts were compiled on different threads:
when, during emission of the first module, the dependence was discovered the
second module (which would provide the required symbol) could not be emitted as
the thread emitting the first module still held the lock.
This patch eliminates this possibility by moving to a finer-grained locking
scheme. Each client holds the module lock only while they are actively operating
on it. To make this finer grained locking simpler/safer to implement this patch
removes the explicit lock method, 'getContextLock', from ThreadSafeModule and
replaces it with a new method, 'withModuleDo', that implicitly locks the context,
calls a user-supplied function object to operate on the Module, then implicitly
unlocks the context before returning the result.
ThreadSafeModule TSM = getModule(...);
size_t NumFunctions = TSM.withModuleDo(
[](Module &M) { // <- context locked before entry to lambda.
return M.size();
});
Existing ORCv2 layers that operate on ThreadSafeModules are updated to use the
new method.
This method is used to introduce Module locking into each of the existing
layers.
llvm-svn: 367686
This patch adds a new llvm-mca flag named -print-imm-hex.
By default, the instruction printer prints immediate operands as decimals. Flag
-print-imm-hex enables the instruction printer to print those operands in hex.
This patch also adds support for MASM binary and hex literal numbers (example
0FFh, 101b).
Added tests to verify the behavior of the new flag. Tests also verify that masm
numeric literal operands are now recognized.
Differential Revision: https://reviews.llvm.org/D65588
llvm-svn: 367671
The note in the documentation suggests this restriction is a compile
time optimization for architectures that make heavy use of
bundling. Allowing virtual registers in a bundle is useful for some
(non-R600) AMDGPU use cases and are infrequent enough to matter.
A more common AMDGPU use case has already been using virtual registers
in bundles since r333691, although never calling finalizeBundle on
them and manually creating the use/def list on the BUNDLE
instruction. This is also relatively infrequent, and only happens for
consecutive sequences of some load/store types.
llvm-svn: 367597
In the approval of D65299, commited as rL367440, I mentioned that my
proposed wording was lacking the word "maximal". It is added now for
correctness.
llvm-svn: 367445
Add user enabled option to create lipo with symlink to llvm-lipo
Used rL326381 for reference.
Differential Revision: https://reviews.llvm.org/D65477
llvm-svn: 367444
Given the example:
header:
br i1 %c, label %next, label %header
next:
br i1 %c2, label %exit, label %header
We end up with a loop containing both header and next. Given that, the describing the loop in terms of cycles is confusing since we have multiple distinct cycles within a single Loop. Standardize on the SCC to clarify.
Differential Revision: https://reviews.llvm.org/D65299
llvm-svn: 367440
Add cmake to the list of packages required for compiling LLVM.
Also move make to the bottom of the list and mark it as optional.
Differential Revision: https://reviews.llvm.org/D65438
llvm-svn: 367395
Summary: The minimum compilers support all have alignas, and we don't use LLVM_ALIGNAS anywhere anymore. This also removes an MSVC diagnostic which, according to the comment above, isn't relevant anymore.
Reviewers: rnk
Subscribers: mgorny, jkorous, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D65458
llvm-svn: 367383
Add a new serializer, using a binary format based on the LLVM bitstream
format.
This format provides a way to serialize the remarks in two modes:
1) Separate mode: the metadata is separate from the remark entries.
2) Standalone mode: the metadata and the remark entries are in the same
file.
The format contains:
* a meta block: container version, container type, string table,
external file path, remark version
* a remark block: type, remark name, pass name, function name, debug
file, debug line, debug column, hotness, arguments (key, value, debug
file, debug line, debug column)
A string table is required for this format, which will be dumped in the
meta block to be consumed before parsing the remark blocks.
On clang itself, we noticed a size reduction of 13.4x compared to YAML,
and a compile-time reduction of between 1.7% and 3.5% on CTMark.
Differential Revision: https://reviews.llvm.org/D63466
Original llvm-svn: 367364
Revert llvm-svn: 367370
llvm-svn: 367372
Add a new serializer, using a binary format based on the LLVM bitstream
format.
This format provides a way to serialize the remarks in two modes:
1) Separate mode: the metadata is separate from the remark entries.
2) Standalone mode: the metadata and the remark entries are in the same
file.
The format contains:
* a meta block: container version, container type, string table,
external file path, remark version
* a remark block: type, remark name, pass name, function name, debug
file, debug line, debug column, hotness, arguments (key, value, debug
file, debug line, debug column)
A string table is required for this format, which will be dumped in the
meta block to be consumed before parsing the remark blocks.
On clang itself, we noticed a size reduction of 13.4x compared to YAML,
and a compile-time reduction of between 1.7% and 3.5% on CTMark.
Differential Revision: https://reviews.llvm.org/D63466
llvm-svn: 367364
Summary:
return_call and return_call_indirect are only valid if the return
types of the callee and caller match. We were previously not enforcing
that, which was producing invalid modules.
Reviewers: aheejin
Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65246
llvm-svn: 367339
The default mode is separate, where the metadata is serialized
separately from the remarks.
Another mode is the standalone mode, where the metadata is serialized
before the remarks, on the same stream.
llvm-svn: 367328
This adds support to the yaml remark parser to be able to parse remarks
directly from the metadata.
This supports parsing separate metadata and following the external file
with the associated metadata, and also a standalone file containing
metadata + remarks all together.
Original llvm-svn: 367148
Revert llvm-svn: 367151
This has a fix for gcc builds.
llvm-svn: 367155
This adds support to the yaml remark parser to be able to parse remarks
directly from the metadata.
This supports parsing separate metadata and following the external file
with the associated metadata, and also a standalone file containing
metadata + remarks all together.
llvm-svn: 367148
This adds a new vectorize predication loop hint:
#pragma clang loop vectorize_predicate(enable)
that can be used to indicate to the vectoriser that all (load/store)
instructions should be predicated (masked). This allows, for example, folding
of the remainder loop into the main loop.
This patch will be followed up with D64916 and D65197. The former is a
refactoring in the loopvectorizer and the groundwork to make tail loop folding
a more general concept, and in the latter the actual tail loop folding
transformation will be implemented.
Differential Revision: https://reviews.llvm.org/D64744
llvm-svn: 366989
I've noticed a lot of confusion around this area recently with key terms being misused in a number of threads. To help reign that in, let's go ahead and document the current terminology and meaning thereof.
My hope is to grow this over time into a broader discussion of canonical loop forms - yes, there are more than one ... many more than one - but for the moment, simply having the key terminology is a good stopping place.
Note: I am landing this *without* an LGTM. All feedback so far has been positive, and trying to apply all of the suggested changes/extensions would cause the review to never end. Instead, I decided to land it with the obvious fixes made based on reviewer comments, then iterate from there.
Differential Revision: https://reviews.llvm.org/D65164
llvm-svn: 366960
Summary:
This patch is part of a patch series to add support for FileCheck
numeric expressions. This specific patch lift the restriction for a
numeric expression to either be a variable definition or a numeric
expression to try to match.
This commit allows a numeric variable to be set to the result of the
evaluation of a numeric expression after it has been matched
successfully. When it happens, the variable is allowed to be used on
the same line since its value is known at match time.
It also makes use of this possibility to reuse the parsing code to
parse a command-line definition by crafting a mirror string of the
-D option with the equal sign replaced by a colon sign, e.g. for option
'-D#NUMVAL=10' it creates the string
'-D#NUMVAL=10 (parsed as [[#NUMVAL:10]])' where the numeric expression
is parsed to define NUMVAL. This result in a few tests needing updating
for the location diagnostics on top of the tests for the new feature.
It also enables empty numeric expression which match any number without
defining a variable. This is done here rather than in commit #5 of the
patch series because it requires to dissociate automatic regex insertion
in RegExStr from variable definition which would make commit #5 even
bigger than it already is.
Copyright:
- Linaro (changes up to diff 183612 of revision D55940)
- GraphCore (changes in later versions of revision D55940 and
in new revision created off D55940)
Reviewers: jhenderson, chandlerc, jdenny, probinson, grimar, arichardson, rnk
Subscribers: hiraditya, llvm-commits, probinson, dblaikie, grimar, arichardson, tra, rnk, kristina, hfinkel, rogfer01, JonChesterfield
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60388
> llvm-svn: 366860
llvm-svn: 366897
Summary:
This patch is part of a patch series to add support for FileCheck
numeric expressions. This specific patch lift the restriction for a
numeric expression to either be a variable definition or a numeric
expression to try to match.
This commit allows a numeric variable to be set to the result of the
evaluation of a numeric expression after it has been matched
successfully. When it happens, the variable is allowed to be used on
the same line since its value is known at match time.
It also makes use of this possibility to reuse the parsing code to
parse a command-line definition by crafting a mirror string of the
-D option with the equal sign replaced by a colon sign, e.g. for option
'-D#NUMVAL=10' it creates the string
'-D#NUMVAL=10 (parsed as [[#NUMVAL:10]])' where the numeric expression
is parsed to define NUMVAL. This result in a few tests needing updating
for the location diagnostics on top of the tests for the new feature.
It also enables empty numeric expression which match any number without
defining a variable. This is done here rather than in commit #5 of the
patch series because it requires to dissociate automatic regex insertion
in RegExStr from variable definition which would make commit #5 even
bigger than it already is.
Copyright:
- Linaro (changes up to diff 183612 of revision D55940)
- GraphCore (changes in later versions of revision D55940 and
in new revision created off D55940)
Reviewers: jhenderson, chandlerc, jdenny, probinson, grimar, arichardson, rnk
Subscribers: hiraditya, llvm-commits, probinson, dblaikie, grimar, arichardson, tra, rnk, kristina, hfinkel, rogfer01, JonChesterfield
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60388
llvm-svn: 366860
This exposes better support to use a string table with a format through
an actual new remark::Format, called yaml-strtab.
This can now be used with -fsave-optimization-record=yaml-strtab.
llvm-svn: 366849
Summary:
Allow IntToPtrInst to carry !dereferenceable metadata tag.
This is valid since !dereferenceable can be only be applied to
pointer type values.
Change-Id: If8a6e3c616f073d51eaff52ab74535c29ed497b4
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64954
llvm-svn: 366826
Until recently, Python_ADDITIONAL_VERSIONS was used to limit LLVM's
Python support to 2.7. Now that both LLVM and LLDB both support Python
3, there's no longer a need to put an arbitrary limit on this.
However, instead of removing the variable, r365692 expanded the list,
which has the (presumably unintentional) side-effect of expression
preference for Python 3.
Instead, as Michal proposed in the original code review, we should just
not set the list at all, and let CMake pick whatever Python interpreter
you have in your path.
This patch removes the Python_ADDITIONAL_VERSIONS variable in llvm,
clang and lld. I've also updated the docs with the default behavior and
how to force a different Python version to be used.
Differential revision: https://reviews.llvm.org/D64894
llvm-svn: 366447
Before, everything was based on some kind of type erased parser
implementation which container a lot of boilerplate code when multiple
formats were to be supported.
This simplifies it by:
* the remark now owns its arguments
* *always* returning an error from the implementation side
* working around the way the YAML parser reports errors: catch them through
callbacks and re-insert them in a proper llvm::Error
* add a CParser wrapper that is used when implementing the C API to
avoid cluttering the C++ API with useless state
* LLVMRemarkParserGetNext now returns an object that needs to be
released to avoid leaking resources
* add a new API to dispose of a remark entry: LLVMRemarkEntryDispose
llvm-svn: 366217
Add "memtag" sanitizer that detects and mitigates stack memory issues
using armv8.5 Memory Tagging Extension.
It is similar in principle to HWASan, which is a software implementation
of the same idea, but there are enough differencies to warrant a new
sanitizer type IMHO. It is also expected to have very different
performance properties.
The new sanitizer does not have a runtime library (it may grow one
later, along with a "debugging" mode). Similar to SafeStack and
StackProtector, the instrumentation pass (in a follow up change) will be
inserted in all cases, but will only affect functions marked with the
new sanitize_memtag attribute.
Reviewers: pcc, hctim, vitalybuka, ostannard
Subscribers: srhines, mehdi_amini, javed.absar, kristof.beyls, hiraditya, cryptoad, steven_wu, dexonsmith, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D64169
llvm-svn: 366123
This is a followup patch for https://reviews.llvm.org/D61810/new/,
which adds new intrinsics preserve_{array,union,struct}_access_index.
Currently, only BPF backend utilizes preserve_{array,union,struct}_access_index
intrinsics, so all tests are compiled with BPF target.
https://reviews.llvm.org/D61524 already added some tests for these
intrinsics, but some of them pretty complex.
This patch added a few unit test cases focusing on individual intrinsic
functions.
Also made a few clarification on language reference for these intrinsics.
Differential Revision: https://reviews.llvm.org/D64606
llvm-svn: 366038
Summary:
This patch is part of a patch series to add support for FileCheck
numeric expressions. This specific patch extend numeric expression to
support an arbitrary number of operands, either variable or literals.
Copyright:
- Linaro (changes up to diff 183612 of revision D55940)
- GraphCore (changes in later versions of revision D55940 and
in new revision created off D55940)
Reviewers: jhenderson, chandlerc, jdenny, probinson, grimar, arichardson, rnk
Subscribers: hiraditya, llvm-commits, probinson, dblaikie, grimar, arichardson, tra, rnk, kristina, hfinkel, rogfer01, JonChesterfield
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60387
llvm-svn: 366001
Summary: This moves away from defaulting to a.out and uses stdin only if stdin has a file redirected to it. This has been discussed on the llvm-dev mailing list [[ https://lists.llvm.org/pipermail/llvm-dev/2019-July/133642.html | here ]].
Reviewers: jhenderson, rupprecht, MaskRay, chrisjackson
Reviewed By: jhenderson, MaskRay
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64290
llvm-svn: 365889
Introduce and deduce "nosync" function attribute to indicate that a function
does not synchronize with another thread in a way that other thread might free memory.
Reviewers: jdoerfert, jfb, nhaehnle, arsenm
Subscribers: wdng, hfinkel, nhaenhle, mehdi_amini, steven_wu,
dexonsmith, arsenm, uenoku, hiraditya, jfb, llvm-commits
Differential Revision: https://reviews.llvm.org/D62766
llvm-svn: 365830
Summary:
Remove references to the multirepo and update the document to
reflect the current state of the github repository.
Reviewers: mehdi_amini, jyknight
Subscribers: jdoerfert, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D58420
llvm-svn: 365645
This adds documentation that describes remarks in LLVM.
It aims at explaining what remarks are, how to enable them, and what
users can do with the different modes.
It lists all the available flags in LLVM (excluding clang), and
describes the expected YAML structure as well as the tools that support
the YAML format today.
Differential Revision: https://reviews.llvm.org/D64355
llvm-svn: 365578
Dump the DWARF information about call sites and call site parameters into
debug info sections.
The patch also provides an interface for the interpretation of instructions
that could load values of a call site parameters in order to generate DWARF
about the call site parameters.
([13/13] Introduce the debug entry values.)
Co-authored-by: Ananth Sowda <asowda@cisco.com>
Co-authored-by: Nikola Prica <nikola.prica@rt-rk.com>
Co-authored-by: Ivan Baev <ibaev@cisco.com>
Differential Revision: https://reviews.llvm.org/D60716
llvm-svn: 365467
Some of the wording in the doc (taken largely from the help text), was a
little imprecise in some cases, so this patch makes it a little more
precise.
Reviewed by: JDevlieghere, probinson
Differential Revision: https://reviews.llvm.org/D64332
llvm-svn: 365451
For background of BPF CO-RE project, please refer to
http://vger.kernel.org/bpfconf2019.html
In summary, BPF CO-RE intends to compile bpf programs
adjustable on struct/union layout change so the same
program can run on multiple kernels with adjustment
before loading based on native kernel structures.
In order to do this, we need keep track of GEP(getelementptr)
instruction base and result debuginfo types, so we
can adjust on the host based on kernel BTF info.
Capturing such information as an IR optimization is hard
as various optimization may have tweaked GEP and also
union is replaced by structure it is impossible to track
fieldindex for union member accesses.
Three intrinsic functions, preserve_{array,union,struct}_access_index,
are introducted.
addr = preserve_array_access_index(base, index, dimension)
addr = preserve_union_access_index(base, di_index)
addr = preserve_struct_access_index(base, gep_index, di_index)
here,
base: the base pointer for the array/union/struct access.
index: the last access index for array, the same for IR/DebugInfo layout.
dimension: the array dimension.
gep_index: the access index based on IR layout.
di_index: the access index based on user/debuginfo types.
For example, for the following example,
$ cat test.c
struct sk_buff {
int i;
int b1:1;
int b2:2;
union {
struct {
int o1;
int o2;
} o;
struct {
char flags;
char dev_id;
} dev;
int netid;
} u[10];
};
static int (*bpf_probe_read)(void *dst, int size, const void *unsafe_ptr)
= (void *) 4;
#define _(x) (__builtin_preserve_access_index(x))
int bpf_prog(struct sk_buff *ctx) {
char dev_id;
bpf_probe_read(&dev_id, sizeof(char), _(&ctx->u[5].dev.dev_id));
return dev_id;
}
$ clang -target bpf -O2 -g -emit-llvm -S -mllvm -print-before-all \
test.c >& log
The generated IR looks like below:
...
define dso_local i32 @bpf_prog(%struct.sk_buff*) #0 !dbg !15 {
%2 = alloca %struct.sk_buff*, align 8
%3 = alloca i8, align 1
store %struct.sk_buff* %0, %struct.sk_buff** %2, align 8, !tbaa !45
call void @llvm.dbg.declare(metadata %struct.sk_buff** %2, metadata !43, metadata !DIExpression()), !dbg !49
call void @llvm.lifetime.start.p0i8(i64 1, i8* %3) #4, !dbg !50
call void @llvm.dbg.declare(metadata i8* %3, metadata !44, metadata !DIExpression()), !dbg !51
%4 = load i32 (i8*, i32, i8*)*, i32 (i8*, i32, i8*)** @bpf_probe_read, align 8, !dbg !52, !tbaa !45
%5 = load %struct.sk_buff*, %struct.sk_buff** %2, align 8, !dbg !53, !tbaa !45
%6 = call [10 x %union.anon]* @llvm.preserve.struct.access.index.p0a10s_union.anons.p0s_struct.sk_buffs(
%struct.sk_buff* %5, i32 2, i32 3), !dbg !53, !llvm.preserve.access.index !19
%7 = call %union.anon* @llvm.preserve.array.access.index.p0s_union.anons.p0a10s_union.anons(
[10 x %union.anon]* %6, i32 1, i32 5), !dbg !53
%8 = call %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(
%union.anon* %7, i32 1), !dbg !53, !llvm.preserve.access.index !26
%9 = bitcast %union.anon* %8 to %struct.anon.0*, !dbg !53
%10 = call i8* @llvm.preserve.struct.access.index.p0i8.p0s_struct.anon.0s(
%struct.anon.0* %9, i32 1, i32 1), !dbg !53, !llvm.preserve.access.index !34
%11 = call i32 %4(i8* %3, i32 1, i8* %10), !dbg !52
%12 = load i8, i8* %3, align 1, !dbg !54, !tbaa !55
%13 = sext i8 %12 to i32, !dbg !54
call void @llvm.lifetime.end.p0i8(i64 1, i8* %3) #4, !dbg !56
ret i32 %13, !dbg !57
}
!19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "sk_buff", file: !3, line: 1, size: 704, elements: !20)
!26 = distinct !DICompositeType(tag: DW_TAG_union_type, scope: !19, file: !3, line: 5, size: 64, elements: !27)
!34 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !26, file: !3, line: 10, size: 16, elements: !35)
Note that @llvm.preserve.{struct,union}.access.index calls have metadata llvm.preserve.access.index
attached to instructions to provide struct/union debuginfo type information.
For &ctx->u[5].dev.dev_id,
. The "%6 = ..." represents struct member "u" with index 2 for IR layout and index 3 for DI layout.
. The "%7 = ..." represents array subscript "5".
. The "%8 = ..." represents union member "dev" with index 1 for DI layout.
. The "%10 = ..." represents struct member "dev_id" with index 1 for both IR and DI layout.
Basically, traversing the use-def chain recursively for the 3rd argument of bpf_probe_read() and
examining all preserve_*_access_index calls, the debuginfo struct/union/array access index
can be achieved.
The intrinsics also contain enough information to regenerate codes for IR layout.
For array and structure intrinsics, the proper GEP can be constructed.
For union intrinsics, replacing all uses of "addr" with "base" should be enough.
The test case ThinLTO/X86/lazyload_metadata.ll is adjusted to reflect the
new addition of the metadata.
Signed-off-by: Yonghong Song <yhs@fb.com>
Differential Revision: https://reviews.llvm.org/D61810
llvm-svn: 365423
For background of BPF CO-RE project, please refer to
http://vger.kernel.org/bpfconf2019.html
In summary, BPF CO-RE intends to compile bpf programs
adjustable on struct/union layout change so the same
program can run on multiple kernels with adjustment
before loading based on native kernel structures.
In order to do this, we need keep track of GEP(getelementptr)
instruction base and result debuginfo types, so we
can adjust on the host based on kernel BTF info.
Capturing such information as an IR optimization is hard
as various optimization may have tweaked GEP and also
union is replaced by structure it is impossible to track
fieldindex for union member accesses.
Three intrinsic functions, preserve_{array,union,struct}_access_index,
are introducted.
addr = preserve_array_access_index(base, index, dimension)
addr = preserve_union_access_index(base, di_index)
addr = preserve_struct_access_index(base, gep_index, di_index)
here,
base: the base pointer for the array/union/struct access.
index: the last access index for array, the same for IR/DebugInfo layout.
dimension: the array dimension.
gep_index: the access index based on IR layout.
di_index: the access index based on user/debuginfo types.
For example, for the following example,
$ cat test.c
struct sk_buff {
int i;
int b1:1;
int b2:2;
union {
struct {
int o1;
int o2;
} o;
struct {
char flags;
char dev_id;
} dev;
int netid;
} u[10];
};
static int (*bpf_probe_read)(void *dst, int size, const void *unsafe_ptr)
= (void *) 4;
#define _(x) (__builtin_preserve_access_index(x))
int bpf_prog(struct sk_buff *ctx) {
char dev_id;
bpf_probe_read(&dev_id, sizeof(char), _(&ctx->u[5].dev.dev_id));
return dev_id;
}
$ clang -target bpf -O2 -g -emit-llvm -S -mllvm -print-before-all \
test.c >& log
The generated IR looks like below:
...
define dso_local i32 @bpf_prog(%struct.sk_buff*) #0 !dbg !15 {
%2 = alloca %struct.sk_buff*, align 8
%3 = alloca i8, align 1
store %struct.sk_buff* %0, %struct.sk_buff** %2, align 8, !tbaa !45
call void @llvm.dbg.declare(metadata %struct.sk_buff** %2, metadata !43, metadata !DIExpression()), !dbg !49
call void @llvm.lifetime.start.p0i8(i64 1, i8* %3) #4, !dbg !50
call void @llvm.dbg.declare(metadata i8* %3, metadata !44, metadata !DIExpression()), !dbg !51
%4 = load i32 (i8*, i32, i8*)*, i32 (i8*, i32, i8*)** @bpf_probe_read, align 8, !dbg !52, !tbaa !45
%5 = load %struct.sk_buff*, %struct.sk_buff** %2, align 8, !dbg !53, !tbaa !45
%6 = call [10 x %union.anon]* @llvm.preserve.struct.access.index.p0a10s_union.anons.p0s_struct.sk_buffs(
%struct.sk_buff* %5, i32 2, i32 3), !dbg !53, !llvm.preserve.access.index !19
%7 = call %union.anon* @llvm.preserve.array.access.index.p0s_union.anons.p0a10s_union.anons(
[10 x %union.anon]* %6, i32 1, i32 5), !dbg !53
%8 = call %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(
%union.anon* %7, i32 1), !dbg !53, !llvm.preserve.access.index !26
%9 = bitcast %union.anon* %8 to %struct.anon.0*, !dbg !53
%10 = call i8* @llvm.preserve.struct.access.index.p0i8.p0s_struct.anon.0s(
%struct.anon.0* %9, i32 1, i32 1), !dbg !53, !llvm.preserve.access.index !34
%11 = call i32 %4(i8* %3, i32 1, i8* %10), !dbg !52
%12 = load i8, i8* %3, align 1, !dbg !54, !tbaa !55
%13 = sext i8 %12 to i32, !dbg !54
call void @llvm.lifetime.end.p0i8(i64 1, i8* %3) #4, !dbg !56
ret i32 %13, !dbg !57
}
!19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "sk_buff", file: !3, line: 1, size: 704, elements: !20)
!26 = distinct !DICompositeType(tag: DW_TAG_union_type, scope: !19, file: !3, line: 5, size: 64, elements: !27)
!34 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !26, file: !3, line: 10, size: 16, elements: !35)
Note that @llvm.preserve.{struct,union}.access.index calls have metadata llvm.preserve.access.index
attached to instructions to provide struct/union debuginfo type information.
For &ctx->u[5].dev.dev_id,
. The "%6 = ..." represents struct member "u" with index 2 for IR layout and index 3 for DI layout.
. The "%7 = ..." represents array subscript "5".
. The "%8 = ..." represents union member "dev" with index 1 for DI layout.
. The "%10 = ..." represents struct member "dev_id" with index 1 for both IR and DI layout.
Basically, traversing the use-def chain recursively for the 3rd argument of bpf_probe_read() and
examining all preserve_*_access_index calls, the debuginfo struct/union/array access index
can be achieved.
The intrinsics also contain enough information to regenerate codes for IR layout.
For array and structure intrinsics, the proper GEP can be constructed.
For union intrinsics, replacing all uses of "addr" with "base" should be enough.
Signed-off-by: Yonghong Song <yhs@fb.com>
Differential Revision: https://reviews.llvm.org/D61810
llvm-svn: 365352
Summary of changes:
- added description of GFX10;
- added description of operands sccz, vccz, lds_direct, etc;
- minor bugfixing and improvements.
llvm-svn: 365347
This patch adds a function attribute, nofree, to indicate that a function does
not, directly or indirectly, call a memory-deallocation function (e.g., free,
C++'s operator delete).
Reviewers: jdoerfert
Differential Revision: https://reviews.llvm.org/D49165
llvm-svn: 365336
Similar to `FILECHECK_OPTS` for FileCheck, `LIT_OPTS` makes it easy to
adjust lit behavior when running the test suite via ninja. For
example:
```
$ LIT_OPTS='--time-tests -vv --filter=threadprivate' \
ninja check-clang-openmp
```
Reviewed By: probinson
Differential Revision: https://reviews.llvm.org/D64135
llvm-svn: 365313
We briefly referred to being able to specify --target=binary without
explaining what binary input/output meant. This change adds a section on
this.
Reviewed by: MaskRay, abrachet
Differential Revision: https://reviews.llvm.org/D64245
llvm-svn: 365312
--section-data, --section-relocations and --section-symbols have no
effect for GNU style ouput. This patch changes the docs to point this
out, as it has caught me out on a couple of occasions.
See also https://bugs.llvm.org/show_bug.cgi?id=42522.
llvm-svn: 365221
Reintroduces the scalable vector IR type from D32530, after it was reverted
a couple of times due to increasing chromium LTO build times. This latest
incarnation removes the walk over aggregate types from the verifier entirely,
in favor of rejecting scalable vectors in the isValidElementType methods in
ArrayType and StructType. This removes the 70% degradation observed with
the second repro tarball from PR42210.
Reviewers: thakis, hans, rengolin, sdesmalen
Reviewed By: sdesmalen
Differential Revision: https://reviews.llvm.org/D64079
llvm-svn: 365203
Summary: Changes "see also" links to use :manpage: instead of plain text or the form `name|name` which was being treated literally, not as a link.
Reviewers: jhenderson, rupprecht
Reviewed By: jhenderson
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63970
llvm-svn: 365159
The --show-children option description describes what it does, and
references the =<offset> parameter of section dump switches. I don't
think it needs to be explained again in the documentation of the
section dump switches too.
Reviewed by: JDevlieghere
Differential Revision: https://reviews.llvm.org/D64132
llvm-svn: 365115
Summary: Removed excess new lines from documentations. As far as I can tell, it seems as though restructured text is agnostic to new lines, the use of new lines was inconsistent and had no effect on how the files were being displayed.
Reviewers: jhenderson, rupprecht, JDevlieghere
Reviewed By: jhenderson
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63971
llvm-svn: 365105
This patch addresses https://bugs.llvm.org/show_bug.cgi?id=42183 by replacing
the stub markdown doc for llvm-objcopy with a full one describing the current
options available in llvm-objcopy.
Reviewed by: jakehehrlich, MaskRay
Differential Revision: https://reviews.llvm.org/D63820
llvm-svn: 365042
The autoconf build system support has been removed a while ago, remove
some outdated references.
Differential Revision: https://reviews.llvm.org/D63608
llvm-svn: 365013
Previously, the llvm-readelf documentation was essentially just a list
of differences to llvm-readobj. Since llvm-readelf is the more likely
goto tool for many people migrating to the LLVM toolchain, it seems like
it would be helpful to document all the switches in the llvm-readelf
document too. This change expands the options listed accordingly.
Additionally, they are unlikely to care what the differences are to
llvm-readobj, since they won't be familiar with the latter as there is
no GNU equivalent, so this change moves the "differences" section to
llvm-readobj's documentation.
Reviewed by: peter.smith
Differential Revision: https://reviews.llvm.org/D63826
llvm-svn: 364800
This change is a result of discussions on list: "GlobalISel: Ambiguous intrinsic semantics problem"
Differential Revision: https://reviews.llvm.org/D59657
llvm-svn: 364610
Update the doc after llvm-svn: 364121 is landed.
With two more trivial fixes that are not related to
--disassemble-functions but still about llvm-objdump.
Reviewers: jhenderson, grimar, MaskRay, rupprecht, peter.smith
Reviewed by: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D63787
llvm-svn: 364573
This patch introduces a new function attribute, willreturn, to indicate
that a call of this function will either exhibit undefined behavior or
comes back and continues execution at a point in the existing call stack
that includes the current invocation.
This attribute guarantees that the function does not have any endless
loops, endless recursion, or terminating functions like abort or exit.
Patch by Hideto Ueno (@uenoku)
Reviewers: jdoerfert
Subscribers: mehdi_amini, hiraditya, steven_wu, dexonsmith, lebedev.ri, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62801
llvm-svn: 364555
The "See Also" section for llvm-nm didn't actually contain any links,
and the tools referred to didn't make much sense (referring to non-LLVM
tools, when we have equivalents, or tools that aren't really to do with
symbol dumping). llvm-objdump's didn't refer to llvm-readelf.
Reviewed by: grimar
Differential Revision: https://reviews.llvm.org/D63875
llvm-svn: 364552
We saw a 70% ThinLTO link time increase in Chromium for Android, see
crbug.com/978817. Sounds like more of PR42210.
> Recommit of D32530 with a few small changes:
> - Stopped recursively walking through aggregates in
> the verifier, so that we don't impose too much
> overhead on large modules under LTO (see PR42210).
> - Changed tests to match; the errors are slightly
> different since they only report the array or
> struct that actually contains a scalable vector,
> rather than all aggregates which contain one in
> a nested member.
> - Corrected an older comment
>
> Reviewers: thakis, rengolin, sdesmalen
>
> Reviewed By: sdesmalen
>
> Differential Revision: https://reviews.llvm.org/D63321
llvm-svn: 364543
Add the IR and the AsmPrinter parts for handling of the DW_OP_entry_values
DWARF operation.
([11/13] Introduce the debug entry values.)
Co-authored-by: Ananth Sowda <asowda@cisco.com>
Co-authored-by: Nikola Prica <nikola.prica@rt-rk.com>
Co-authored-by: Ivan Baev <ibaev@cisco.com>
Differential Revision: https://reviews.llvm.org/D60866
llvm-svn: 364542
Sphinx allows for definitions of command-line options using
`.. option <name>` and references to those options via `:option:<name>`.
However, it looks like there is no scoping of these options by default,
meaning that links can end up pointing to incorrect documents. See for
example the llvm-mca document, which contains references to -o that,
prior to this patch, pointed to a different document. What's worse is
that these links appear to be non-deterministic in which one is picked
(on my machine, some references end up pointing to opt, whereas on the
live docs, they point to llvm-dwarfdump, for example).
The fix is to add the .. program <name> tag. This essentially namespaces
the options (definitions and references) to the named program, ensuring
that the links are kept correct.
Reviwed by: andreadb
Differential Revision: https://reviews.llvm.org/D63873
llvm-svn: 364538
Add an attribute into the MachineFunction that tracks call site info.
([8/13] Introduce the debug entry values.)
Co-authored-by: Ananth Sowda <asowda@cisco.com>
Co-authored-by: Nikola Prica <nikola.prica@rt-rk.com>
Co-authored-by: Ivan Baev <ibaev@cisco.com>
Differential Revision: https://reviews.llvm.org/D61061
llvm-svn: 364506
A unique DISubprogram may be attached to a function declaration used for
call site debug info.
([6/13] Introduce the debug entry values.)
Co-authored-by: Ananth Sowda <asowda@cisco.com>
Co-authored-by: Nikola Prica <nikola.prica@rt-rk.com>
Co-authored-by: Ivan Baev <ibaev@cisco.com>
Differential Revision: https://reviews.llvm.org/D60713
llvm-svn: 364500
Summary:
Implements direct and indirect tail calls enabled by the 'tail-call'
feature in both DAG ISel and FastISel. Updates existing call tests and
adds new tests including a binary encoding test.
Reviewers: aheejin
Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62877
llvm-svn: 364445
As detailed in https://bugs.llvm.org/show_bug.cgi?id=42253, there were a
number of issues in the llvm-symbolizer documentation. This patch fixes
them by:
1. Adding [addresses...] to the synopsis, and matching the formatting
of other tools.
2. Rewriting the description to fix grammar issues and mention other
usage options.
3. Rewriting the examples to be easier to read.
4. Re-ordering the options into alphabetical order.
5. Improving the text of some of the option descriptions, and adding
some examples to individual options.
6. Splitting the Mach-O options into a separate section of the
document.
7. Standardizing on double dashes for long options throughout the file.
8. Adding a reference to the llvm-addr2line document.
Reviewed by: mtrent, ikudrin
Differential Revision: https://reviews.llvm.org/D63651
llvm-svn: 364410
Introduce the debug info flag that indicates that a parameter has unchanged
value throughout a function. This info will be used to emit the expressions
with DW_OP_entry_value.
([4/13] Introduce the debug entry values.)
Co-authored-by: Ananth Sowda <asowda@cisco.com>
Co-authored-by: Nikola Prica <nikola.prica@rt-rk.com>
Co-authored-by: Ivan Baev <ibaev@cisco.com>
Differential Revision: https://reviews.llvm.org/D58034
llvm-svn: 364406
"To" selects an odd-numbered GPR, and "Te" an even one. There are some
8.1-M instructions that have one too few bits in their register fields
and require registers of particular parity, without necessarily using
a consecutive even/odd pair.
Also, the constraint letter "t" should select an MVE q-register, when
MVE is present. This didn't need any source changes, but some extra
tests have been added.
Reviewers: dmgreen, samparker, SjoerdMeijer
Subscribers: javed.absar, eraman, kristof.beyls, hiraditya, cfe-commits, llvm-commits
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D60709
llvm-svn: 364331
There were a number of issues with the llvm-readobj documentation. The
following points were raised in https://bugs.llvm.org/show_bug.cgi?id=42255,
and have been fixed in this patch:
1. The description section claimed "The tool and its output is
primarily designed for use in FileCheck-based tests" which is not
really the case any more.
2. The documentation used single-dash long options for option names,
but references in the help text to other options exclusively used
double-dashes. Fixed by standardising on double-dashes for all
long-form options.
3. The majority of options available and in the help text were not
present in the documentation. This patch adds them.
4. Several aliases, both long and short, were missing, e.g. --relocs.
Additionally, this patch improves the documentation by:
1. Splitting the options into categories based on the file format they
are specific to.
2. Updating the Exit Status section to correctly mention that errors
lead to a non-zero exit code.
3. Adding a See Also section referencing other similar LLVM tools.
4. Improving/correcting some of the descriptions of options that did
not quite match up with what llvm-readobj does.
Reviewed by: peter.smith, MaskRay, mtrent
Differential Revision: https://reviews.llvm.org/D63719
llvm-svn: 364306
Summary:
The directive defines a symbol as an group/local memory (LDS) symbol.
LDS symbols behave similar to common symbols for the purposes of ELF,
using the processor-specific SHN_AMDGPU_LDS as section index.
It is the linker and/or runtime loader's job to "instantiate" LDS symbols
and resolve relocations that reference them.
It is not possible to initialize LDS memory (not even zero-initialize
as for .bss).
We want to be able to link together objects -- starting with relocatable
objects, but possible expanding to shared objects in the future -- that
access LDS memory in a flexible way.
LDS memory is in an address space that is entirely separate from the
address space that contains the program image (code and normal data),
so having program segments for it doesn't really make sense.
Furthermore, we want to be able to compile multiple kernels in a
compilation unit which have disjoint use of LDS memory. In that case,
we may want to place LDS symbols differently for different kernels
to save memory (LDS memory is very limited and physically private to
each kernel invocation), so we can't simply place LDS symbols in a
.lds section.
Hence this solution where LDS symbols always stay undefined.
Change-Id: I08cbc37a7c0c32f53f7b6123aa0afc91dbc1748f
Reviewers: arsenm, rampitec, t-tye, b-sumner, jsjodin
Subscribers: kzhuravl, jvesely, wdng, yaxunl, dstuttard, tpr, rupprecht, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61493
llvm-svn: 364296
There was a stub for llvm-cxxfilt, but it didn't describe the options.
Additionally, it was in markdown, which was causing issues, so as
discussed in https://reviews.llvm.org/D63211, this change replaces the
existing stub with an RST file.
Reviewed by: MaskRay, mattd
Differential Revision: https://reviews.llvm.org/D63722
llvm-svn: 364287
There were several options missing from the documentation. This patch
adds them as well as improving some wording and separating the Mach-O
only options into a separate section.
Fixes https://bugs.llvm.org/show_bug.cgi?id=42234.
Reviewed by: MaskRay
Differential Revision: https://reviews.llvm.org/D63655
llvm-svn: 364176
The existing symbol code documentation was very incomplete. This patch
adds the missing codes, and defines them based on the current code
behaviour.
Fixes https://bugs.llvm.org/show_bug.cgi?id=42231.
Reviewed by: rupprecht, mtrent, MaskRay
Differential Revision: https://reviews.llvm.org/D63327
llvm-svn: 364171
Many LLVM-based tools already support response files (i.e. files
containing a list of options, specified with '@'). This change simply
updates the documentation and help text for some of these tools to
include it. I haven't attempted to fix all tools, just a selection that
I am interested in.
I've taken the opportunity to add some tests for --help behaviour, where
they were missing. We could expand these tests, but I don't think that's
within scope of this patch.
This fixes https://bugs.llvm.org/show_bug.cgi?id=42233 and
https://bugs.llvm.org/show_bug.cgi?id=42236.
Reviewed by: grimar, MaskRay, jkorous
Differential Revision: https://reviews.llvm.org/D63597
llvm-svn: 364036
The llvm-objdump document was missing many options, and there were also
some style issues with it. This patches fixes all but the first issue
listed in https://bugs.llvm.org/show_bug.cgi?id=42249 by:
1. Adding missing options and commands.
2. Standardising on double dashes for long-options throughout.
3. Moving Mach-O specific options to a separate section.
4. Removing options that don't exist or aren't relevant to
llvm-objdump.
Reviewed by: MaskRay, mtrent, alexshap
Differential Revision: https://reviews.llvm.org/D63606
llvm-svn: 364019
Summary:
Stop referring to "numeric expression", using simply the term
"expression" instead. Likewise for numeric operation since operations
are only used in numeric expressions.
Reviewers: jhenderson, jdenny, probinson, arichardson
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63500
llvm-svn: 363901
Recommit of D32530 with a few small changes:
- Stopped recursively walking through aggregates in
the verifier, so that we don't impose too much
overhead on large modules under LTO (see PR42210).
- Changed tests to match; the errors are slightly
different since they only report the array or
struct that actually contains a scalable vector,
rather than all aggregates which contain one in
a nested member.
- Corrected an older comment
Reviewers: thakis, rengolin, sdesmalen
Reviewed By: sdesmalen
Differential Revision: https://reviews.llvm.org/D63321
llvm-svn: 363658
This patch documents that LLVM does not describe all changes in variable
locations during the prologue and the epilogue. The debugger doesn't /
shouldn't step through that portion of the function anyway, and describing
every location through such stages would bloat location lists.
Perform some minor cleanup at the same time,
* Fix an enumerated list
* Document that dbg.declare intrinsics have their variable location recorded
in a MachineFunction table, not with DBG_VALUE meta-insts
* Adds frame-indexes to the list of things that can be operands to
DBG_VALUEs.
Differential Revision: https://reviews.llvm.org/D63083
llvm-svn: 363654
The goal is to improve hwasan's error reporting for stack use-after-return by
recording enough information to allow the specific variable that was accessed
to be identified based on the pointer's tag. Currently we record the PC and
lower bits of SP for each stack frame we create (which will eventually be
enough to derive the base tag used by the stack frame) but that's not enough
to determine the specific tag for each variable, which is the stack frame's
base tag XOR a value (the "tag offset") that is unique for each variable in
a function.
In IR, the tag offset is most naturally represented as part of a location
expression on the llvm.dbg.declare instruction. However, the presence of the
tag offset in the variable's actual location expression is likely to confuse
debuggers which won't know about tag offsets, and moreover the tag offset
is not required for a debugger to determine the location of the variable on
the stack, so at the DWARF level it is represented as an attribute so that
it will be ignored by debuggers that don't know about it.
Differential Revision: https://reviews.llvm.org/D63119
llvm-svn: 363635
The docs and help text for --show-parents and --show-children were a bit
inconsistent. The help text claimed they had an effect when "=<offset>"
was used, whereas the doc said it had an effect when "--find" or
"--name" were used. This change changes the doc to mention "=<offset>"
and removes this reference from the help text, to avoid having a very
long description in the help text (it still says "when selectively
printing entries").
Reviewed by: JDevlieghere, aprantl
Differential Revision: https://reviews.llvm.org/D63275
llvm-svn: 363380
Support loading code coverage data from regular archives, thin archives,
and from MachO universal binaries which contain archives.
Testing: check-llvm, check-profile (with {A,UB}San enabled)
rdar://51538999
Differential Revision: https://reviews.llvm.org/D63232
llvm-svn: 363325
I find the current documentation of poison somewhat confusing,
mainly because its use of "undefined behavior" doesn't seem to
align with our usual interpretation (of immediate UB). Especially
the sentence "any instruction that has a dependence on a poison
value has undefined behavior" is very confusing.
Clarify poison semantics by:
* Replacing the introductory paragraph with the standard rationale
for having poison values.
* Spelling out that instructions depending on poison return poison.
* Spelling out how we go from a poison value to immediate undefined
behavior and give the two examples we currently use in ValueTracking.
* Spelling out that side effects depending on poison are UB.
Differential Revision: https://reviews.llvm.org/D63044
llvm-svn: 363320
This fixes https://bugs.llvm.org/show_bug.cgi?id=42185.
llvm-dwarfdump's documentation was missing a number of options and other
behaviours. This change tries to fix up the documentation by adding
these missing items.
Reviewed by: JDevlieghere
Differential Revision: https://reviews.llvm.org/D63217
llvm-svn: 363264
This patch uses the mechanism from D62995 to strengthen the
definitions of the reduction intrinsics by letting the scalar
result/accumulator type be overloaded from the vector element type.
For example:
; The LLVM LangRef specifies that the scalar result must equal the
; vector element type, but this is not checked/enforced by LLVM.
declare i32 @llvm.experimental.vector.reduce.or.i32.v4i32(<4 x i32> %a)
This patch changes that into:
declare i32 @llvm.experimental.vector.reduce.or.v4i32(<4 x i32> %a)
Which has the type-constraint more explicit and causes LLVM to check
the result type with the vector element type.
Reviewers: RKSimon, arsenm, rnk, greened, aemerson
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D62996
llvm-svn: 363240
The information for -archs flag is added to llvm-lipo.rst.
Patch by Anusha Basana <anusha.basana@gmail.com>
Differential Revision: https://reviews.llvm.org/D63100
llvm-svn: 363182
Summary: In this patch, I updated `load` instruction syntax and fixed function definition. Besides, I re-named some variables to make them obey SSA rule.
Reviewers: MaskRay
Reviewed By: MaskRay
Subscribers: llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63186
llvm-svn: 363142
The --print-size help text and documentation claimed that the size was
printed instead of the address, but this is incorrect. It is printed as
well as the address. This patch fixes this issue.
Reviewed by: MaskRay, mtrent, ruiu
Differential Revision: https://reviews.llvm.org/D63142
llvm-svn: 363136
Summary:
This splits out a section in the command guide for llvm tools that can be used as replacements for GNU tools. For pages that didn't exist, I added stub pages that can be individually filled in by followup patches.
Tested by running `ninja docs-llvm-html` and inspecting locally.
Reviewers: jhenderson, MaskRay, grimar, alexshap
Reviewed By: jhenderson, MaskRay, grimar
Subscribers: smeenai, arphaman, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D63014
llvm-svn: 363100
